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Sample records for cre recombinase correlates

  1. Generation of chickens expressing Cre recombinase.

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    Leighton, Philip A; Pedersen, Darlene; Ching, Kathryn; Collarini, Ellen J; Izquierdo, Shelley; Jacob, Roy; van de Lavoir, Marie-Cecile

    2016-10-01

    Cre recombinase has been extensively used for genome engineering in transgenic mice yet its use in other species has been more limited. Here we describe the generation of transgenic chickens expressing Cre recombinase. Green fluorescent protein (GFP)-positive chicken primordial germ cells were stably transfected with β-actin-Cre-recombinase using phiC31 integrase and transgenic chickens were generated. Cre recombinase activity was verified by mating Cre birds to birds carrying a floxed transgene. Floxed sequences were only excised in offspring from roosters that inherited the Cre recombinase but were excised in all offspring from hens carrying the Cre recombinase irrespective of the presence of the Cre transgene. The Cre recombinase transgenic birds were healthy and reproductively normal. The Cre and GFP genes in two of the lines were closely linked whereas the genes segregated independently in a third line. These founders allowed development of GFP-expressing and non-GFP-expressing Cre recombinase lines. These lines of birds create a myriad of opportunities to study developmentally-regulated and tissue-specific expression of transgenes in chickens.

  2. Spontaneous recombinase activity of Cre-ERT2 in vivo.

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    Kristianto, Jasmin; Johnson, Michael G; Zastrow, Ryley K; Radcliff, Abigail B; Blank, Robert D

    2017-06-01

    Inducible Cre-ERT recombinase technology is widely used for gene targeting studies. The second generation of inducible Cre-ERT recombinase, hemizygous B6.129S-Tg(UBC-cre/ERT2)1Ejb/J (hereafter abbreviated as Cre-ERT2), a fusion of a mutated estrogen receptor and Cre recombinase, was engineered to be more efficient and specific than the original Cre-ERT. The putative mechanism of selective Cre-mediated recombination is Cre sequestration in the cytoplasm in the basal state with translocation to the nucleus only in the presence of tamoxifen. We utilized both a reporter mouse (B6.129 (Cg)-Gt(ROSA)26Sor tm4(ACTB-tdTomato,-EGFP)Luo /J) and endothelin converting enzyme-1 floxed transgenic mouse line to evaluate Cre-ERT2 activity. We observed spontaneous Cre activity in both settings. Unintended Cre activity is a confounding factor that has a potentially large impact on data interpretation. Thus, it is important to consider background Cre activity in experimental design.

  3. A new location to split Cre recombinase for protein fragment complementation.

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    Rajaee, Maryam; Ow, David W

    2017-11-01

    We have previously described a recombinase-mediated gene stacking system in which the Cre recombinase is used to remove lox-site flanked DNA no longer needed after each round of Bxb1 integrase-mediated site-specific integration. The Cre recombinase can be conveniently introduced by hybridization with a cre-expressing plant. However, maintaining an efficient cre-expressing line over many generations can be a problem, as high production of this DNA-binding protein might interfere with normal chromosome activities. To counter this selection against high Cre activity, we considered a split-cre approach, in which Cre activity is reconstituted after separate parts of Cre are brought into the same genome by hybridization. To insure that the recombinase-mediated gene stacking system retains its freedom to operate, we tested for new locations to split Cre into complementing fragments. In this study, we describe testing four new locations for splitting the Cre recombinase for protein fragment complementation and show that the two fragments of Cre split between Lys244 and Asn245 can reconstitute activity that is comparable to that of wild-type Cre. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  4. Cre recombinase expression can result in phenotypic aberrations in plants

    NARCIS (Netherlands)

    Coppoolse, E.; Vroomen, de M.J.; Roelofs, D.; Smit, J.; Gennip, van F.; Hersmus, B.J.M.; Nijkamp, H.J.J.; Haaren, van M.J.

    2003-01-01

    The cre recombinase gene was stably introduced and expressed in tomato, petunia and Nicotiana tabacum. Some plants expressing the cre gene driven by a CaMV 35S promoter displayed growth retardation and a distinct pattern of chlorosis in their leaves. Although no direct relation can be proven between

  5. Cre recombinase expression can result in phenotypic aberrations in plants

    NARCIS (Netherlands)

    Coppoolse, Eric R; de Vroomen, Marianne J; Roelofs, Dick; Smit, Jaap; van Gennip, Femke; Hersmus, Bart J M; Nijkamp, H John J; van Haaren, Mark J J

    The cre recombinase gene was stably introduced and expressed in tomato, petunia and Nicotiana tabacum. Some plants expressing the cre gene driven by a CaMV 35S promoter displayed growth retardation and a distinct pattern of chlorosis in their leaves. Although no direct relation can be proven between

  6. Marker Removal in Transgenic Plants Using Cre Recombinase Delivered with Potato Virus X.

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    Kopertekh, Lilya; Schiemann, Joachim

    2017-01-01

    In this chapter we present an alternative method to develop marker-free transgenic plants. It makes use of the Cre/loxP recombination system from bacteriophage P1 and consists of two essential components. The first component is the transgenic plant containing a loxP-flanked marker gene. The second component is a cre transient expression vector based on potato virus X. The great benefit of this transient delivery method consists in the avoidance of stable integration of the cre recombinase gene into the plant genome. Upon infection of the loxP-target plant with PVX-Cre, the virus spreads systemically through the plant and causes the recombinase-mediated excision of the marker gene. Marker-free transgenic loci can be transmitted to the progeny by plant regeneration from PVX-Cre systemically infected leaves or self-pollination of virus-infected plants. The protocol covers generation of loxP-target transgenic plants, PVX-mediated delivery of Cre recombinase protein, phenotypic and molecular analysis of recombination events, and transmission of marker-free transgenic loci to the next generation. The transient expression system described in this chapter can be adapted for marker gene removal in other plant species that are amenable for virus infection.

  7. Regulation of Cre recombinase by ligand-induced complementation of inactive fragments.

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    Jullien, Nicolas; Sampieri, François; Enjalbert, Alain; Herman, Jean-Paul

    2003-11-01

    Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. To overcome this, we have developed DiCre, a regulatable fragment complementation system for Cre. The enzyme was split into two moieties that were fused to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12-rapamycin-associated protein), respectively. These can be efficiently heterodimerized by rapamycin. Several variants, based on splitting Cre at different sites and using different linker peptides, were tested in an indicator cell line. The fusion proteins, taken separately, had no recombinase activity. Stable transformants, co-expressing complementing fragments based on splitting Cre between Asn59 and Asn60, displayed low background activity affecting 0.05-0.4% of the cells. Rapamycin induced a rapid recombination, reaching 100% by 48-72 h, with an EC50 of 0.02 nM. Thus, ligand-induced dimerization can efficiently regulate Cre, and should be useful to achieve a tight temporal control of its activity, such as in the case of the creation of conditional knock-out animals.

  8. Construction of Marker-Free Transgenic Strains of Chlamydomonas reinhardtii Using a Cre/loxP-Mediated Recombinase System.

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    Kasai, Yuki; Harayama, Shigeaki

    2016-01-01

    The Escherichia coli bacteriophage P1 encodes a site-specific recombinase called Cre and two 34-bp target sites of Cre recombinase called loxP. The Cre/loxP system has been used to achieve targeted insertion and precise deletion in many animal and plant genomes. The Cre/loxP system has particularly been used for the removal of selectable marker genes to create marker-free transgenic organisms. For the first time, we applied the Cre/loxP-mediated site-specific recombination system to Chlamydomonas reinhardtii to construct marker-free transgenic strains. Specifically, C. reinhardtii strains cc4350 and cc124 carrying an aphVIII expression cassette flanked by two direct repeats of loxP were constructed. Separately, a synthetic Cre recombinase gene (CrCRE), the codons of which were optimized for expression in C. reinhardtii, was synthesized, and a CrCRE expression cassette was introduced into strain cc4350 carrying a single copy of the loxP-flanked aphVIII expression cassette. Among 46 transformants carrying the CrCRE expression cassette stably, the excision of aphVIII by CrCre recombinase was observed only in one transformant. We then constructed an expression cassette of an in-frame fusion of ble to CrCRE via a short linker peptide. The product of ble (Ble) is a bleomycin-binding protein that confers resistance to bleomycin-related antibiotics such as Zeocin and localizes in the nucleus. Therefore, the ble-(linker)-CrCRE fusion protein is expected to localize in the nucleus. When the ble-(linker)-CrCRE expression cassette was integrated into the genome of strain cc4350 carrying a single copy of the loxP-flanked aphVIII expression cassette, CrCre recombinase-mediated excision of the aphVIII expression cassette was observed at a frequency higher than that in stable transformants of the CrCRE expression cassette. Similarly, from strain cc124 carrying a single loxP-flanked aphVIII expression cassette, the aphVIII expression cassette was successfully excised after

  9. Cell Type-Specific Manipulation with GFP-Dependent Cre Recombinase

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    Tang, Jonathan C Y; Rudolph, Stephanie; Dhande, Onkar S; Abraira, Victoria E; Choi, Seungwon; Lapan, Sylvain; Drew, Iain R; Drokhlyansky, Eugene; Huberman, Andrew D; Regehr, Wade G; Cepko, Constance L

    2016-01-01

    Summary There are many transgenic GFP reporter lines that allow visualization of specific populations of cells. Using such lines for functional studies requires a method that transforms GFP into a molecule that enables genetic manipulation. Here we report the creation of a method that exploits GFP for gene manipulation, Cre Recombinase Dependent on GFP (CRE-DOG), a split component system that uses GFP and its derivatives to directly induce Cre/loxP recombination. Using plasmid electroporation and AAV viral vectors, we delivered CRE-DOG to multiple GFP mouse lines, leading to effective recombination selectively in GFP-labeled cells. Further, CRE-DOG enabled optogenetic control of these neurons. Beyond providing a new set of tools for manipulation of gene expression selectively in GFP+ cells, we demonstrate that GFP can be used to reconstitute the activity of a protein not known to have a modular structure, suggesting that this strategy might be applicable to a wide range of proteins. PMID:26258682

  10. Using the Textpresso Site-Specific Recombinases Web server to identify Cre expressing mouse strains and floxed alleles.

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    Condie, Brian G; Urbanski, William M

    2014-01-01

    Effective tools for searching the biomedical literature are essential for identifying reagents or mouse strains as well as for effective experimental design and informed interpretation of experimental results. We have built the Textpresso Site Specific Recombinases (Textpresso SSR) Web server to enable researchers who use mice to perform in-depth searches of a rapidly growing and complex part of the mouse literature. Our Textpresso Web server provides an interface for searching the full text of most of the peer-reviewed publications that report the characterization or use of mouse strains that express Cre or Flp recombinase. The database also contains most of the publications that describe the characterization or analysis of strains carrying conditional alleles or transgenes that can be inactivated or activated by site-specific recombinases such as Cre or Flp. Textpresso SSR complements the existing online databases that catalog Cre and Flp expression patterns by providing a unique online interface for the in-depth text mining of the site specific recombinase literature.

  11. Delivery of the Cre recombinase by a self-deleting lentiviral vector: efficient gene targeting in vivo

    NARCIS (Netherlands)

    Pfeifer, A.; Brandon, E. P.; Kootstra, N.; Gage, F. H.; Verma, I. M.

    2001-01-01

    The Cre recombinase (Cre) from bacteriophage P1 is an important tool for genetic engineering in mammalian cells. We constructed lentiviral vectors that efficiently deliver Cre in vitro and in vivo. Surprisingly, we found a significant reduction in proliferation and an accumulation in the G(2)/M

  12. Cytokeratin 19 promoter directs the expression of Cre recombinase in various epithelia of transgenic mice.

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    Zhao, Gui-Feng; Zhao, Shuang; Liu, Jia-Jie; Wu, Ji-Cheng; He, Hao-Yu; Ding, Xiao-Qing; Yu, Xue-Wen; Huang, Ke-Qiang; Li, Zhi-Jie; Zheng, Hua-Chuan

    2017-03-14

    Cytokeratin 19 (K19) is expressed in various differentiated cells, including gastric, intestinal and bronchial epithelial cells, and liver duct cells. Here, we generated a transgenic mouse line, K19-Cre, in which the expression of Cre recombinase was controlled by the promoter of K19. To test the tissue distribution and excision activity of Cre recombinase, K19-Cre transgenic mice were bred with Rosa26 reporter strain and a mouse strain that carries PTEN conditional alleles (PTENLoxp/Loxp). At mRNA level, Cre was strongly expressed in the stomach, lung and intestine, while in stomach, lung, and liver at protein level. The immunoreactivity to Cre was strongly observed the cytoplasm of gastric, bronchial and intestinal epithelial cells. Cre activity was detectable in gastric, bronchial and intestinal epithelial cells, according to LacZ staining. In K19-Cre/PTEN Loxp/Loxp mice, PTEN was abrogated in stomach, intestine, lung, liver and breast, the former two of which were verified by in situ PCR. There appeared breast cancer with PTEN loss. These data suggest that K19 promoter may be a useful tool to study the pathophysiological functions of cytokeratin 19-positive cells, especially gastrointestinal epithelial cells. Cell specificity of neoplasia is not completely attributable to the cell-specific expression of oncogenes and cell-specific loss of tumor suppressor genes.

  13. Targeting of Mesenchymal Stromal Cells by Cre-Recombinase Transgenes Commonly Used to Target Osteoblast Lineage Cells.

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    Zhang, Jingzhu; Link, Daniel C

    2016-11-01

    The targeting specificity of tissue-specific Cre-recombinase transgenes is a key to interpreting phenotypes associated with their use. The Ocn-Cre and Dmp1-Cre transgenes are widely used to target osteoblasts and osteocytes, respectively. Here, we used high-resolution microscopy of bone sections and flow cytometry to carefully define the targeting specificity of these transgenes. These transgenes were crossed with Cxcl12 gfp mice to identify Cxcl12-abundant reticular (CAR) cells, which are a perivascular mesenchymal stromal population implicated in hematopoietic stem/progenitor cell maintenance. We show that in addition to osteoblasts, Ocn-Cre targets a majority of CAR cells and arteriolar pericytes. Surprisingly, Dmp1-Cre also targets a subset of CAR cells, in which expression of osteoblast-lineage genes is enriched. Finally, we introduce a new tissue-specific Cre-recombinase, Tagln-Cre, which efficiently targets osteoblasts, a majority of CAR cells, and both venous sinusoidal and arteriolar pericytes. These data show that Ocn-Cre and Dmp1-Cre target broader stromal cell populations than previously appreciated and may aid in the design of future studies. Moreover, these data highlight the heterogeneity of mesenchymal stromal cells in the bone marrow and provide tools to interrogate this heterogeneity. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

  14. Dermal Delivery of Constructs Encoding Cre Recombinase to Induce Skin Tumors in PtenLoxP/LoxP;BrafCA/+ Mice

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    Marcel A. Deken

    2016-12-01

    Full Text Available Current genetically-engineered mouse melanoma models are often based on Tyr::CreERT2-controlled MAPK pathway activation by the BRAFV600E mutation and PI3K pathway activation by loss of PTEN. The major drawback of these models is the occurrence of spontaneous tumors caused by leakiness of the Tyr::CreERT2 system, hampering long-term experiments. To address this problem, we investigated several approaches to optimally provide local delivery of Cre recombinase, including injection of lentiviral particles, DNA tattoo administration and particle-mediated gene transfer, to induce melanomas in PtenLoxP/LoxP;BrafCA/+ mice lacking the Tyr::CreERT2 allele. We found that dermal delivery of the Cre recombinase gene under the control of a non-specific CAG promoter induced the formation of melanomas, but also keratoacanthoma and squamous cell carcinomas. Delivery of Cre recombinase DNA under the control of melanocyte-specific promoters in PtenLoxP/LoxP;BrafCA/+ mice resulted in sole melanoma induction. The growth rate and histological features of the induced tumors were similar to 4-hydroxytamoxifen-induced tumors in Tyr::CreERT2;PtenLoxP/LoxP;BrafCA/+ mice, while the onset of spontaneous tumors was prevented completely. These novel induction methods will allow long-term experiments in mouse models of skin malignancies.

  15. Transgenic mice for a tamoxifen-induced, conditional expression of the Cre recombinase in osteoclasts.

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    Maria Arantzazu Sanchez-Fernandez

    Full Text Available BACKGROUND: Studies on osteoclasts, the bone resorbing cells, have remained limited due to the lack of transgenic mice allowing the conditional knockout of genes in osteoclasts at any time during development or adulthood. METHODOLOGY/PRINCIPAL FINDING: We report here on the generation of transgenic mice which specifically express a tamoxifen-inducible Cre recombinase in osteoclasts. These mice, generated on C57BL/6 and FVB background, express a fusion Cre recombinase-ERT2 protein whose expression is driven by the promoter of cathepsin K (CtsK, a gene highly expressed in osteoclasts. We tested the cellular specificity of Cre activity in CtsKCreERT2 strains by breeding with Rosa26LacZ reporter mice. PCR and histological analyses of the CtsKCreERT2LacZ positive adult mice and E17.5 embryos show that Cre activity is restricted largely to bone tissue. In vitro, primary osteoclasts derived from the bone marrow of CtsKCreERT2+/-LacZ+/- adult mice show a Cre-dependent β-galactosidase activity after tamoxifen stimulation. CONCLUSIONS/SIGNIFICANCE: We have generated transgenic lines that enable the tamoxifen-induced, conditional deletion of loxP-flanked genes in osteoclasts, thus circumventing embryonic and postnatal gene lethality and avoiding gene deletion in other cell types. Such CtsKCreERT2 mice provide a convenient tool to study in vivo the different facets of osteoclast function in bone physiology during different developmental stages and adulthood of mice.

  16. Heme oxygenase-1 expression protects the heart from acute injury caused by inducible Cre recombinase.

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    Hull, Travis D; Bolisetty, Subhashini; DeAlmeida, Angela C; Litovsky, Silvio H; Prabhu, Sumanth D; Agarwal, Anupam; George, James F

    2013-08-01

    The protective effect of heme oxygenase-1 (HO-1) expression in cardiovascular disease has been previously demonstrated using transgenic animal models in which HO-1 is constitutively overexpressed in the heart. However, the temporal requirements for protection by HO-1 induction relative to injury have not been investigated, but are essential to employ HO-1 as a therapeutic strategy in human cardiovascular disease states. Therefore, we generated mice with cardiac-specific, tamoxifen (TAM)-inducible overexpression of a human HO-1 (hHO-1) transgene (myosin heavy chain (MHC)-HO-1 mice) by breeding mice with cardiac-specific expression of a TAM-inducible Cre recombinase (MHC-Cre mice), with mice containing an hHO-1 transgene preceded by a floxed-stop signal. MHC-HO-1 mice overexpress HO-1 mRNA and the enzymatically active protein following TAM administration (40 mg/kg body weight on 2 consecutive days). In MHC-Cre controls, TAM administration leads to severe, acute cardiac toxicity, cardiomyocyte necrosis, and 80% mortality by day 3. This cardiac toxicity is accompanied by a significant increase in inflammatory cells in the heart that are predominantly neutrophils. In MHC-HO-1 mice, HO-1 overexpression ameliorates the depression of cardiac function and high mortality rate observed in MHC-Cre mice following TAM administration and attenuates cardiomyocyte necrosis and neutrophil infiltration. These results highlight that HO-1 induction is sufficient to prevent the depression of cardiac function observed in mice with TAM-inducible Cre recombinase expression by protecting the heart from necrosis and neutrophil infiltration. These findings are important because MHC-Cre mice are widely used in cardiovascular research despite the limitations imposed by Cre-induced cardiac toxicity, and also because inflammation is an important pathological component of many human cardiovascular diseases.

  17. Generation of NSE-MerCreMer transgenic mice with tamoxifen inducible Cre activity in neurons.

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    Mandy Ka Man Kam

    Full Text Available To establish a genetic tool for conditional deletion or expression of gene in neurons in a temporally controlled manner, we generated a transgenic mouse (NSE-MerCreMer, which expressed a tamoxifen inducible type of Cre recombinase specifically in neurons. The tamoxifen inducible Cre recombinase (MerCreMer is a fusion protein containing Cre recombinase with two modified estrogen receptor ligand binding domains at both ends, and is driven by the neural-specific rat neural specific enolase (NSE promoter. A total of two transgenic lines were established, and expression of MerCreMer in neurons of the central and enteric nervous systems was confirmed. Transcript of MerCreMer was detected in several non-neural tissues such as heart, liver, and kidney in these lines. In the background of the Cre reporter mouse strain Rosa26R, Cre recombinase activity was inducible in neurons of adult NSE-MerCreMer mice treated with tamoxifen by intragastric gavage, but not in those fed with corn oil only. We conclude that NSE-MerCreMer lines will be useful for studying gene functions in neurons for the conditions that Cre-mediated recombination resulting in embryonic lethality, which precludes investigation of gene functions in neurons through later stages of development and in adult.

  18. Redesign of the monomer–monomer interface of Cre recombinase yields an obligate heterotetrameric complex

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    Zhang, Chi; Myers, Connie A.; Qi, Zongtai; Mitra, Robi D.; Corbo, Joseph C.; Havranek, James J.

    2015-01-01

    Cre recombinase catalyzes the cleavage and religation of DNA at loxP sites. The enzyme is a homotetramer in its functional state, and the symmetry of the protein complex enforces a pseudo-palindromic symmetry upon the loxP sequence. The Cre-lox system is a powerful tool for many researchers. However, broader application of the system is limited by the fixed sequence preferences of Cre, which are determined by both the direct DNA contacts and the homotetrameric arrangement of the Cre monomers. As a first step toward achieving recombination at arbitrary asymmetric target sites, we have broken the symmetry of the Cre tetramer assembly. Using a combination of computational and rational protein design, we have engineered an alternative interface between Cre monomers that is functional yet incompatible with the wild-type interface. Wild-type and engineered interface halves can be mixed to create two distinct Cre mutants, neither of which are functional in isolation, but which can form an active heterotetramer when combined. When these distinct mutants possess different DNA specificities, control over complex assembly directly discourages recombination at unwanted half-site combinations, enhancing the specificity of asymmetric site recombination. The engineered Cre mutants exhibit this assembly pattern in a variety of contexts, including mammalian cells. PMID:26365240

  19. Tie-1-directed expression of Cre recombinase in endothelial cells of embryoid bodies and transgenic mice

    DEFF Research Database (Denmark)

    Gustafsson, E; Brakebusch, C; Hietanen, K

    2001-01-01

    Tissue-specific gene inactivation using the Cre-loxP system has become an important tool to unravel functions of genes when the conventional null mutation is lethal. We report here the generation of a transgenic mouse line expressing Cre recombinase in endothelial cells. In order to avoid...... the production and screening of multiple transgenic lines we used embryonic stem cell and embryoid body technology to identify recombinant embryonic stem cell clones with high, endothelial-specific Cre activity. One embryonic stem cell clone that showed high Cre activity in endothelial cells was used to generate...... germline chimeras. The in vivo efficiency and specificity of the transgenic Cre was analysed by intercrossing the tie-1-Cre line with the ROSA26R reporter mice. At initial stages of vascular formation (E8-9), LacZ staining was detected in almost all cells of the forming vasculature. Between E10 and birth...

  20. Cell-specific cre recombinase expression allows selective ablation of glutamate receptors from mouse horizontal cells.

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    Sebastian Ströh

    Full Text Available In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57, a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99% and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl. In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼ 50% in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼ 75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less

  1. Cell-Specific Cre Recombinase Expression Allows Selective Ablation of Glutamate Receptors from Mouse Horizontal Cells

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    Janssen-Bienhold, Ulrike; Schultz, Konrad; Cimiotti, Kerstin; Weiler, Reto; Willecke, Klaus; Dedek, Karin

    2013-01-01

    In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57), a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99%) and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl). In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼50%) in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less excitatory input

  2. Identification of a minimal functional linker in human topoisomerase I by domain swapping with Cre recombinase

    DEFF Research Database (Denmark)

    Hougaard, Rikke Frøhlich; Juul, Sissel; Vinther, Maria

    2008-01-01

    . In this study we replace 86 amino acids including the linker domain of the cellular type IB topoisomerase, human topoisomerase I, with four, six, or eight amino acids from the corresponding short loop region in Cre recombinase. In vitro characterization of the resulting chimeras, denoted Cropos, reveals...

  3. Redesign of the monomer-monomer interface of Cre recombinase yields an obligate heterotetrameric complex.

    Science.gov (United States)

    Zhang, Chi; Myers, Connie A; Qi, Zongtai; Mitra, Robi D; Corbo, Joseph C; Havranek, James J

    2015-10-15

    Cre recombinase catalyzes the cleavage and religation of DNA at loxP sites. The enzyme is a homotetramer in its functional state, and the symmetry of the protein complex enforces a pseudo-palindromic symmetry upon the loxP sequence. The Cre-lox system is a powerful tool for many researchers. However, broader application of the system is limited by the fixed sequence preferences of Cre, which are determined by both the direct DNA contacts and the homotetrameric arrangement of the Cre monomers. As a first step toward achieving recombination at arbitrary asymmetric target sites, we have broken the symmetry of the Cre tetramer assembly. Using a combination of computational and rational protein design, we have engineered an alternative interface between Cre monomers that is functional yet incompatible with the wild-type interface. Wild-type and engineered interface halves can be mixed to create two distinct Cre mutants, neither of which are functional in isolation, but which can form an active heterotetramer when combined. When these distinct mutants possess different DNA specificities, control over complex assembly directly discourages recombination at unwanted half-site combinations, enhancing the specificity of asymmetric site recombination. The engineered Cre mutants exhibit this assembly pattern in a variety of contexts, including mammalian cells. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. Cre recombinase expression or topical tamoxifen treatment do not affect retinal structure and function, neuronal vulnerability or glial reactivity in the mouse eye.

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    Boneva, S K; Groß, T R; Schlecht, A; Schmitt, S I; Sippl, C; Jägle, H; Volz, C; Neueder, A; Tamm, E R; Braunger, B M

    2016-06-14

    Mice with a constitutive or tamoxifen-induced Cre recombinase (Cre) expression are frequently used research tools to allow the conditional deletion of target genes via the Cre-loxP system. Here we analyzed for the first time in a comprehensive and comparative way, whether retinal Cre expression or topical tamoxifen treatment itself would cause structural or functional changes, including changes in the expression profiles of molecular markers, glial reactivity and photoreceptor vulnerability. To this end, we characterized the transgenic α-Cre, Lmop-Cre and the tamoxifen-inducible CAGG-CreER™ mouse lines, all having robust Cre expression in the neuronal retina. In addition, we characterized the effects of topical tamoxifen treatment itself in wildtype mice. We performed morphometric analyses, immunohistochemical staining, in vivo ERG and angiography analyses and realtime RT-PCR analyses. Furthermore, the influence of Cre recombinase or topical tamoxifen exposure on neuronal vulnerability was studied by using light damage as a model for photoreceptor degeneration. Taken together, neither the expression of Cre, nor topical tamoxifen treatment caused detectable changes in retinal structure and function, the expression profiles of investigated molecular markers, glial reactivity and photoreceptor vulnerability. We conclude that the Cre-loxP system and its induction through tamoxifen is a safe and reliable method to delete desired target genes in the neural retina. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. A novel Cre recombinase imaging system for tracking lymphotropic virus infection in vivo.

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    Bernadette M Dutia

    2009-08-01

    Full Text Available Detection, isolation, and identification of individual virus infected cells during long term infection are critical to advance our understanding of mechanisms of pathogenesis for latent/persistent viruses. However, current approaches to study these viruses in vivo have been hampered by low sensitivity and effects of cell-type on expression of viral encoded reporter genes. We have designed a novel Cre recombinase (Cre-based murine system to overcome these problems, and thereby enable tracking and isolation of individual in vivo infected cells.Murine gammaherpesvirus 68 (MHV-68 was used as a prototypic persistent model virus. A Cre expressing recombinant virus was constructed and characterised. The virus is attenuated both in lytic virus replication, producing ten-fold lower lung virus titres than wild type virus, and in the establishment of latency. However, despite this limitation, when the sEGFP7 mouse line containing a Cre-activated enhanced green fluorescent protein (EGFP was infected with the Cre expressing virus, sites of latent and persistent virus infection could be identified within B cells and macrophages of the lymphoid system on the basis of EGFP expression. Importantly, the use of the sEGFP7 mouse line which expresses high levels of EGFP allowed individual virus positive cells to be purified by FACSorting. Virus gene expression could be detected in these cells. Low numbers of EGFP positive cells could also be detected in the bone marrow.The use of this novel Cre-based virus/mouse system allowed identification of individual latently infected cells in vivo and may be useful for the study and long-term monitoring of other latent/persistent virus infections.

  6. Imaging Voltage in Genetically Defined Neuronal Subpopulations with a Cre Recombinase-Targeted Hybrid Voltage Sensor.

    Science.gov (United States)

    Bayguinov, Peter O; Ma, Yihe; Gao, Yu; Zhao, Xinyu; Jackson, Meyer B

    2017-09-20

    Genetically encoded voltage indicators create an opportunity to monitor electrical activity in defined sets of neurons as they participate in the complex patterns of coordinated electrical activity that underlie nervous system function. Taking full advantage of genetically encoded voltage indicators requires a generalized strategy for targeting the probe to genetically defined populations of cells. To this end, we have generated a mouse line with an optimized hybrid voltage sensor (hVOS) probe within a locus designed for efficient Cre recombinase-dependent expression. Crossing this mouse with Cre drivers generated double transgenics expressing hVOS probe in GABAergic, parvalbumin, and calretinin interneurons, as well as hilar mossy cells, new adult-born neurons, and recently active neurons. In each case, imaging in brain slices from male or female animals revealed electrically evoked optical signals from multiple individual neurons in single trials. These imaging experiments revealed action potentials, dynamic aspects of dendritic integration, and trial-to-trial fluctuations in response latency. The rapid time response of hVOS imaging revealed action potentials with high temporal fidelity, and enabled accurate measurements of spike half-widths characteristic of each cell type. Simultaneous recording of rapid voltage changes in multiple neurons with a common genetic signature offers a powerful approach to the study of neural circuit function and the investigation of how neural networks encode, process, and store information. SIGNIFICANCE STATEMENT Genetically encoded voltage indicators hold great promise in the study of neural circuitry, but realizing their full potential depends on targeting the sensor to distinct cell types. Here we present a new mouse line that expresses a hybrid optical voltage sensor under the control of Cre recombinase. Crossing this line with Cre drivers generated double-transgenic mice, which express this sensor in targeted cell types. In

  7. Cre recombinase activity is inhibited in vivo but not ex vivo by a mutation in the asymmetric spacer region of the distal loxP site.

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    Arguello, Tania; Moraes, Carlos T

    2015-11-01

    The cre/loxP recombination system is a valuable tool used to generate tissue specific genomic rearrangements in mouse models. The deletion of a region of interest flanked by two loxP sites is accomplished by the recombinase (cre) enzyme, which binds to the inverted repeat segments of two loxP sites and recognition of a conserved TA sequence in the asymmetric central spacer region "ATAACTTCGTATA -NNNTANNN-TATACGAAGTTAT. In vivo, we found that a single T to C mutation at position 4 of the central spacer region in the distal (3') loxP site, completely inhibited the recombination reaction in two conditional mouse models. These mice were generated using a mitochondrial methionyl-tRNA formyltransferase (Mtfmt) gene targeted construct and cre transgene under the control of tissue-specific promoters: calcium/calmodulin-dependent kinase II alpha (Camk2a-cre) and myosin light polypeptide 1 (Myl1-cre). Surprisingly, transient transfection of a plasmid expressing cre in dermal fibroblasts derived from the same mutant floxed Mtfmt((loxP/loxP)) mice line, successfully deleted the region of interest. This study demonstrates the sequence specificity required in vivo, the possibility of bypassing this limitation by expressing high levels of cre recombinase ex vivo and raises concerns related to the quality control of large scale production of gene targeted constructs and mice. genesis 53:695-700, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  8. Targeted transgene insertion into the CHO cell genome using Cre recombinase-incorporating integrase-defective retroviral vectors.

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    Kawabe, Yoshinori; Shimomura, Takuya; Huang, Shuohao; Imanishi, Suguru; Ito, Akira; Kamihira, Masamichi

    2016-07-01

    Retroviral vectors have served as efficient gene delivery tools in various biotechnology fields. However, viral DNA is randomly inserted into the genome, which can cause problems, such as insertional mutagenesis and gene silencing. Previously, we reported a site-specific gene integration system, in which a transgene is integrated into a predetermined chromosomal locus of Chinese hamster ovary (CHO) cells using integrase-defective retroviral vectors (IDRVs) and Cre recombinase. In this system, a Cre expression plasmid is transfected into founder cells before retroviral transduction. In practical applications of site-specific gene modification such as for hard-to-transfect cells or for in vivo gene delivery, both the transgene and the Cre protein into retroviral virions should be encapsulate. Here, we generated novel hybrid IDRVs in which viral genome and enzymatically active Cre can be delivered (Cre-IDRVs). Cre-IDRVs encoding marker genes, neomycin resistance and enhanced green fluorescent protein (EGFP), flanked by wild-type and mutated loxP sites were produced using an expression plasmid for a chimeric protein of Cre and retroviral gag-pol. After analyzing the incorporation of the Cre protein into retroviral virions by Western blotting, the Cre-IDRV was infected into founder CHO cells, in which marker genes (hygromycin resistance and red fluorescent protein) flanked with corresponding loxP sites are introduced into the genome. G418-resistant colonies expressing GFP appeared and the site-specific integration of the transgene into the expected chromosomal site was confirmed by PCR and sequencing of amplicons. Moreover, when Cre-IDRV carried a gene expression unit for a recombinant antibody, the recombinant cells in which the antibody expression cassette was integrated in a site-specific manner were generated and the cells produced the recombinant antibody. This method may provide a promising tool to perform site-specific gene modification according to Cre

  9. Conditional transgenesis using Dimerizable Cre (DiCre).

    Science.gov (United States)

    Jullien, Nicolas; Goddard, Isabelle; Selmi-Ruby, Samia; Fina, Jean-Luc; Cremer, Harold; Herman, Jean-Paul

    2007-12-26

    Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. We have recently developed a conceptually new approach to regulate Cre recombinase, that we have called Dimerizable Cre or DiCre. It is based on splitting Cre into two inactive moieties and fusing them to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12-rapamycin associated protein), respectively. These latter can be efficiently hetero-dimerized by rapamycin, leading to the reinstatement of Cre activity. We have been able to show, using in vitro approaches, that this ligand-induced dimerization is an efficient way to regulate Cre activity, and presents a low background activity together with a high efficiency of recombination following dimerization. To test the in vivo performance of this system, we have, in the present work, knocked-in DiCre into the Rosa26 locus of mice. To evaluate the performance of the DiCre system, mice have been mated with indicator mice (Z/EG or R26R) and Cre-induced recombination was examined following activation of DiCre by rapamycin during embryonic development or after birth of progenies. No recombination could be observed in the absence of treatment of the animals, indicating a lack of background activity of DiCre in the absence of rapamycin. Postnatal rapamycin treatment (one to five daily injection, 10 mg/kg i.p) induced recombination in a number of different tissues of progenies such as liver, heart, kidney, muscle, etc. On the other hand, recombination was at a very low level following in utero treatment of DiCrexR26R mice. In conclusion, DiCre has indeed the potentiality to be used to establish conditional Cre-deleter mice. An added advantage of this system is that, contrary to other modulatable Cre systems, it offers the possibility of obtaining regulated recombination in a combinatorial manner, i.e. induce recombination at

  10. Conditional transgenesis using Dimerizable Cre (DiCre.

    Directory of Open Access Journals (Sweden)

    Nicolas Jullien

    Full Text Available Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. We have recently developed a conceptually new approach to regulate Cre recombinase, that we have called Dimerizable Cre or DiCre. It is based on splitting Cre into two inactive moieties and fusing them to FKBP12 (FK506-binding protein and FRB (binding domain of the FKBP12-rapamycin associated protein, respectively. These latter can be efficiently hetero-dimerized by rapamycin, leading to the reinstatement of Cre activity. We have been able to show, using in vitro approaches, that this ligand-induced dimerization is an efficient way to regulate Cre activity, and presents a low background activity together with a high efficiency of recombination following dimerization. To test the in vivo performance of this system, we have, in the present work, knocked-in DiCre into the Rosa26 locus of mice. To evaluate the performance of the DiCre system, mice have been mated with indicator mice (Z/EG or R26R and Cre-induced recombination was examined following activation of DiCre by rapamycin during embryonic development or after birth of progenies. No recombination could be observed in the absence of treatment of the animals, indicating a lack of background activity of DiCre in the absence of rapamycin. Postnatal rapamycin treatment (one to five daily injection, 10 mg/kg i.p induced recombination in a number of different tissues of progenies such as liver, heart, kidney, muscle, etc. On the other hand, recombination was at a very low level following in utero treatment of DiCrexR26R mice. In conclusion, DiCre has indeed the potentiality to be used to establish conditional Cre-deleter mice. An added advantage of this system is that, contrary to other modulatable Cre systems, it offers the possibility of obtaining regulated recombination in a combinatorial manner, i.e. induce

  11. Spatial and temporal lineage analysis of a Pitx3-driven Cre-recombinase knock-in mouse model.

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    Marten P Smidt

    Full Text Available Development and function of mesodiencephalic dopaminergic (mdDA neurons has received a lot of scientific interest since these neurons are critically involved in neurological diseases as Parkinson and psychiatric diseases as schizophrenia, depression and attention deficit hyperactivity disorder (ADHD. The understanding of the molecular processes that lead to normal development and function of mdDA neurons has provided insight in the pathology and provided critical information on new treatment paradigms. In order to be able to study specific genetic ablation in mdDA neurons a new tools was developed that drives Cre-recombinase under the control of the Pitx3 locus. The Pitx3 gene is well known for its specific expression in mdDA neurons and is present at the onset of terminal differentiation. Analysis of newly generated Pitx3-Cre knock-in mice shows that Cre expression, measured through the activation of eYfp by removal of a "Stop" signal (LoxP-Stop-LoxP-eYfp reporter mouse, is present at the onset of terminal differentiation and mimics closely the native Pitx3 expression domain. In conclusion, we present here a new Cre-driver mouse model to be used in the restricted ablation of interesting genes in mdDA neurons in order to improve our understanding of the underlying molecular programming.

  12. Efficient delivery of Cre-recombinase to neurons in vivo and stable transduction of neurons using adeno-associated and lentiviral vectors

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    Sablitzky Fred

    2004-01-01

    Full Text Available Abstract Background Inactivating genes in vivo is an important technique for establishing their function in the adult nervous system. Unfortunately, conventional knockout mice may suffer from several limitations including embryonic or perinatal lethality and the compensatory regulation of other genes. One approach to producing conditional activation or inactivation of genes involves the use of Cre recombinase to remove loxP-flanked segments of DNA. We have studied the effects of delivering Cre to the hippocampus and neocortex of adult mice by injecting replication-deficient adeno-associated virus (AAV and lentiviral (LV vectors into discrete regions of the forebrain. Results Recombinant AAV-Cre, AAV-GFP (green fluorescent protein and LV-Cre-EGFP (enhanced GFP were made with the transgene controlled by the cytomegalovirus promoter. Infecting 293T cells in vitro with AAV-Cre and LV-Cre-EGFP resulted in transduction of most cells as shown by GFP fluorescence and Cre immunoreactivity. Injections of submicrolitre quantities of LV-Cre-EGFP and mixtures of AAV-Cre with AAV-GFP into the neocortex and hippocampus of adult Rosa26 reporter mice resulted in strong Cre and GFP expression in the dentate gyrus and moderate to strong labelling in specific regions of the hippocampus and in the neocortex, mainly in neurons. The pattern of expression of Cre and GFP obtained with AAV and LV vectors was very similar. X-gal staining showed that Cre-mediated recombination had occurred in neurons in the same regions of the brain, starting at 3 days post-injection. No obvious toxic effects of Cre expression were detected even after four weeks post-injection. Conclusion AAV and LV vectors are capable of delivering Cre to neurons in discrete regions of the adult mouse brain and producing recombination.

  13. Chromosomal localisation of the CD4cre transgene in B6·Cg-Tg(Cd4-cre)1Cwi mice.

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    Westendorf, Kerstin; Durek, Pawel; Ayew, Samia; Mashreghi, Mir-Farzin; Radbruch, Andreas

    2016-09-01

    The B6·Cg-Tg(Cd4-cre)1Cwi line expresses CRE recombinase under the control of the promoter and regulatory elements of the Cd4 gene. Here we show that CRE recombinase expression reduces the number and frequencies of CD4 positive subsets in a dose-dependent manner and localize the integration site of the transgenic construct to position 60335693-60341285 (qD) of chromosome 3. The insert contains at least 15 complete sequential copies of the transgenic construct. Based on this information we describe a novel PCR assay for genetic typing of transgenic mice. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Germline recombination in a novel Cre transgenic line, Prl3b1-Cre mouse.

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    Al-Soudy, Al-Sayed; Nakanishi, Tsuyoshi; Mizuno, Seiya; Hasegawa, Yoshikazu; Shawki, Hossam H; Katoh, Megumi C; Basha, Walaa A; Ibrahim, Abdelaziz E; El-Shemy, Hany A; Iseki, Hiroyoshi; Yoshiki, Atsushi; Hiromori, Youhei; Nagase, Hisamitsu; Takahashi, Satoru; Oishi, Hisashi; Sugiyama, Fumihiro

    2016-07-01

    Spermatogenesis is a complex and highly regulated process by which spermatogonial stem cells differentiate into spermatozoa. To better understand the molecular mechanisms of the process, the Cre/loxP system has been widely utilized for conditional gene knockout in mice. In this study, we generated a transgenic mouse line that expresses Cre recombinase under the control of the 2.5 kbp of the Prolactin family 3, subfamily b, member 1 (Prl3b1) gene promoter (Prl3b1-cre). Prl3b1 was initially reported to code for placental lactogen 2 (PL-2) protein in placenta along with increased expression toward the end of pregnancy. PL-2 was found to be expressed in germ cells in the testis, especially in spermatocytes. To analyze the specificity and efficiency of Cre recombinase activity in Prl3b1-cre mice, the mice were mated with reporter R26GRR mice, which express GFP ubiquitously before and tdsRed exclusively after Cre recombination. The systemic examination of Prl3b1-cre;R26GRR mice revealed that tdsRed-positive cells were detected only in the testis and epididymis. Fluorescence imaging of Prl3b1-cre;R26GRR testes suggested that Cre-mediated recombination took place in the germ cells with approximately 74% efficiency determined by in vitro fertilization. In conclusion, our results suggest that the Prl3b1-cre mice line provides a unique resource to understand testicular germ-cell development. genesis 54:389-397, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Viral Cre-LoxP tools aid genome engineering in mammalian cells.

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    Sengupta, Ranjita; Mendenhall, Amy; Sarkar, Nandita; Mukherjee, Chandreyee; Afshari, Amirali; Huang, Joseph; Lu, Biao

    2017-01-01

    Targeted nucleases have transformed genome editing technology, providing more efficient methods to make targeted changes in mammalian genome. In parallel, there is an increasing demand of Cre-LoxP technology for complex genome manipulation such as large deletion, addition, gene fusion and conditional removal of gene sequences at the target site. However, an efficient and easy-to-use Cre-recombinase delivery system remains lacking. We designed and constructed two sets of expression vectors for Cre-recombinase using two highly efficient viral systems, the integrative lentivirus and non-integrative adeno associated virus. We demonstrate the effectiveness of those methods in Cre-delivery into stably-engineered HEK293 cells harboring LoxP-floxed red fluorescent protein (RFP) and puromycin (Puro) resistant reporters. The delivered Cre recombinase effectively excised the floxed RFP-Puro either directly or conditionally, therefore validating the function of these molecular tools. Given the convenient options of two selections markers, these viral-based systems offer a robust and easy-to-use tool for advanced genome editing, expanding complicated genome engineering to a variety of cell types and conditions. We have developed and functionally validated two viral-based Cre-recombinase delivery systems for efficient genome manipulation in various mammalian cells. The ease of gene delivery with the built-in reporters and inducible element enables live cell monitoring, drug selection and temporal knockout, broadening applications of genome editing.

  16. Single molecule TPM analysis of the catalytic pentad mutants of Cre and Flp site-specific recombinases: contributions of the pentad residues to the pre-chemical steps of recombination

    Science.gov (United States)

    Fan, Hsiu-Fang; Cheng, Yong-Song; Ma, Chien-Hui; Jayaram, Makkuni

    2015-01-01

    Cre and Flp site-specific recombinase variants harboring point mutations at their conserved catalytic pentad positions were characterized using single molecule tethered particle motion (TPM) analysis. The findings reveal contributions of these amino acids to the pre-chemical steps of recombination. They suggest functional differences between positionally conserved residues in how they influence recombinase-target site association and formation of ‘non-productive’, ‘pre-synaptic’ and ‘synaptic’ complexes. The most striking difference between the two systems is noted for the single conserved lysine. The pentad residues in Cre enhance commitment to recombination by kinetically favoring the formation of pre-synaptic complexes. These residues in Flp serve a similar function by promoting Flp binding to target sites, reducing non-productive binding and/or enhancing the rate of assembly of synaptic complexes. Kinetic comparisons between Cre and Flp, and between their derivatives lacking the tyrosine nucleophile, are consistent with a stronger commitment to recombination in the Flp system. The effect of target site orientation (head-to-head or head-to-tail) on the TPM behavior of synapsed DNA molecules supports the selection of anti-parallel target site alignment prior to the chemical steps. The integrity of the synapse, whose establishment/stability is fostered by strand cleavage in the case of Flp but not Cre, appears to be compromised by the pentad mutations. PMID:25765648

  17. The generation and characterization of novel Col1a1FRT-Cre-ER-T2-FRT and Col1a1FRT-STOP-FRT-Cre-ER-T2 mice for sequential mutagenesis

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    Minsi Zhang

    2015-09-01

    Full Text Available Novel genetically engineered mouse models using the Cre-loxP or the Flp-FRT systems have generated useful reagents to manipulate the mouse genome in a temporally-regulated and tissue-specific manner. By incorporating a constitutive Cre driver line into a mouse model in which FRT-regulated genes in other cell types are regulated by Flp-FRT recombinase, gene expression can be manipulated simultaneously in separate tissue compartments. This application of dual recombinase technology can be used to dissect the role of stromal cells in tumor development and cancer therapy. Generating mice in which Cre-ERT2 is expressed under Flp-FRT-mediated regulation would enable step-wise manipulation of the mouse genome using dual recombinase technology. Such next-generation mouse models would enable sequential mutagenesis to better model cancer and define genes required for tumor maintenance. Here, we generated novel genetically engineered mice that activate or delete Cre-ERT2 in response to Flp recombinase. To potentially utilize the large number of Cre-loxP-regulated transgenic alleles that have already been targeted into the Rosa26 locus, such as different reporters and mutant genes, we targeted the two novel Cre-ERT2 alleles into the endogenous Col1a1 locus for ubiquitous expression. In the Col1a1FRT-Cre-ER-T2-FRT mice, Flp deletes Cre-ERT2, so that Cre-ERT2 is only expressed in cells that have never expressed Flp. In contrast, in the Col1a1FRT-STOP-FRT-Cre-ER-T2 mice, Flp removes the STOP cassette to allow Cre-ERT2 expression so that Cre-ERT2 is only expressed in cells that previously expressed Flp. These two new novel mouse strains will be complementary to each other and will enable the exploration of complex biological questions in development, normal tissue homeostasis and cancer.

  18. The generation and characterization of novel Col1a1FRT-Cre-ER-T2-FRT and Col1a1FRT-STOP-FRT-Cre-ER-T2 mice for sequential mutagenesis

    Science.gov (United States)

    Zhang, Minsi; Kirsch, David G.

    2015-01-01

    ABSTRACT Novel genetically engineered mouse models using the Cre-loxP or the Flp-FRT systems have generated useful reagents to manipulate the mouse genome in a temporally-regulated and tissue-specific manner. By incorporating a constitutive Cre driver line into a mouse model in which FRT-regulated genes in other cell types are regulated by Flp-FRT recombinase, gene expression can be manipulated simultaneously in separate tissue compartments. This application of dual recombinase technology can be used to dissect the role of stromal cells in tumor development and cancer therapy. Generating mice in which Cre-ERT2 is expressed under Flp-FRT-mediated regulation would enable step-wise manipulation of the mouse genome using dual recombinase technology. Such next-generation mouse models would enable sequential mutagenesis to better model cancer and define genes required for tumor maintenance. Here, we generated novel genetically engineered mice that activate or delete Cre-ERT2 in response to Flp recombinase. To potentially utilize the large number of Cre-loxP-regulated transgenic alleles that have already been targeted into the Rosa26 locus, such as different reporters and mutant genes, we targeted the two novel Cre-ERT2 alleles into the endogenous Col1a1 locus for ubiquitous expression. In the Col1a1FRT-Cre-ER-T2-FRT mice, Flp deletes Cre-ERT2, so that Cre-ERT2 is only expressed in cells that have never expressed Flp. In contrast, in the Col1a1FRT-STOP-FRT-Cre-ER-T2 mice, Flp removes the STOP cassette to allow Cre-ERT2 expression so that Cre-ERT2 is only expressed in cells that previously expressed Flp. These two new novel mouse strains will be complementary to each other and will enable the exploration of complex biological questions in development, normal tissue homeostasis and cancer. PMID:26183214

  19. Construction of a viral T2A-peptide based knock-in mouse model for enhanced Cre recombinase activity and fluorescent labeling of podocytes.

    Science.gov (United States)

    Koehler, Sybille; Brähler, Sebastian; Braun, Fabian; Hagmann, Henning; Rinschen, Markus M; Späth, Martin R; Höhne, Martin; Wunderlich, F Thomas; Schermer, Bernhard; Benzing, Thomas; Brinkkoetter, Paul T

    2017-06-01

    Podocyte injury is a key event in glomerular disease leading to proteinuria and opening the path toward glomerular scarring. As a consequence, glomerular research strives to discover molecular mechanisms and signaling pathways affecting podocyte health. The hNphs2.Cre mouse model has been a valuable tool to manipulate podocyte-specific genes and to label podocytes for lineage tracing and purification. Here we designed a novel podocyte-specific tricistronic Cre mouse model combining codon improved Cre expression and fluorescent cell labeling with mTomato under the control of the endogenous Nphs2 promoter using viral T2A-peptides. Independent expression of endogenous podocin, codon improved Cre, and mTomato was confirmed by immunofluorescence, fluorescent activated cell sorting and protein analyses. Nphs2 pod.T2A.ciCre.T2A.mTomato/wild-type mice developed normally and did not show any signs of glomerular disease or off-target effects under basal conditions and in states of disease. Nphs2 pod.T2A.ciCre.T2A.mTomato/wild-type -mediated gene recombination was superior to conventional hNphs2.Cre mice-mediated gene recombination. Last, we compared Cre efficiency in a disease model by mating Nphs2 pod.T2A.ciCre.T2A.mTomato/wild-type and hNphs2.Cre mice to Phb2 fl/fl mice. The podocyte-specific Phb2 knockout by Nphs2 pod.T2A.ciCre.T2A.mTomato/wild-type mice resulted in an aggravated glomerular injury as compared to a podocyte-specific Phb2 gene deletion triggered by hNphs2.Cre. Thus, we generated the first tricistronic podocyte mouse model combining enhanced Cre recombinase efficiency and fluorescent labeling in podocytes without the need for additional matings with conventional reporter mouse lines. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  20. Robust inducible Cre recombinase activity in the human malaria parasite Plasmodium falciparum enables efficient gene deletion within a single asexual erythrocytic growth cycle.

    Science.gov (United States)

    Collins, Christine R; Das, Sujaan; Wong, Eleanor H; Andenmatten, Nicole; Stallmach, Robert; Hackett, Fiona; Herman, Jean-Paul; Müller, Sylke; Meissner, Markus; Blackman, Michael J

    2013-05-01

    Asexual blood stages of the malaria parasite, which cause all the pathology associated with malaria, can readily be genetically modified by homologous recombination, enabling the functional study of parasite genes that are not essential in this part of the life cycle. However, no widely applicable method for conditional mutagenesis of essential asexual blood-stage malarial genes is available, hindering their functional analysis. We report the application of the DiCre conditional recombinase system to Plasmodium falciparum, the causative agent of the most dangerous form of malaria. We show that DiCre can be used to obtain rapid, highly regulated site-specific recombination in P. falciparum, capable of excising loxP-flanked sequences from a genomic locus with close to 100% efficiency within the time-span of a single erythrocytic growth cycle. DiCre-mediated deletion of the SERA5 3' UTR failed to reduce expression of the gene due to the existence of alternative cryptic polyadenylation sites within the modified locus. However, we successfully used the system to recycle the most widely used drug resistance marker for P. falciparum, human dihydrofolate reductase, in the process producing constitutively DiCre-expressing P. falciparum clones that have broad utility for the functional analysis of essential asexual blood-stage parasite genes. © 2013 John Wiley & Sons Ltd.

  1. Pou4f2 knock-in Cre mouse: A multifaceted genetic tool for vision researchers.

    Science.gov (United States)

    Simmons, Aaron B; Bloomsburg, Samuel J; Billingslea, Samuel A; Merrill, Morgan M; Li, Shuai; Thomas, Marshall W; Fuerst, Peter G

    2016-01-01

    A transgenic mouse that expresses Cre recombinase under control of the Pou4f2-promoter (also referred to as Brn-3b and Brn-3.2) was characterized. Pou4f2 expression has been reported in a subset of retinal ganglion cells (RGCs) in the retina, in the midbrain, and in the germline. In this study, we characterize the expression pattern of this Cre-recombinase line and report its utility in targeted deletion, temporal deletion, RGC depletion, and germline targeting, which can be regulated by the sex of the Cre-carrying mouse. Pou4f2(Cre) was mapped by using a combination of PCR and sequencing of PCR products to better understand the construct and to locate where it was inserted within the Pou4f2 locus. Cre expression patterns were examined by crossing Pou4f2(Cre/+) mice to Cre reporter mice. Immunohistochemistry was used to further define the pattern of Cre expression and Cre-mediated recombination within the retina, brain, and other tissues. An internal ribosome entry site (IRES)-Cre cassette was inserted into the Pou4f2 gene disrupting normal gene function, as verified by the depletion of RGCs in mice homozygous for the insert. Pou4f2(Cre) expression was observed in the retina, brain, peripheral neurons, and male germ cells. Germline recombination was observed when the sire carried the Cre and the target for recombination. In all other breeding schemes, recombination was observed within subsets of cells within the retina, brain, intestines, heart, and gonads. In the retina, Cre efficiently targets recombination in neurons within the RGC layer (RGL), the inner nuclear layer (INL), and a small percentage of photoreceptors, activity that has not been previously reported. Unlike most other Cre lines active in the inner retina, recombination in Müller and other glia was not observed in mice carrying Pou4f2(Cre) . Within the visual centers of the brain, Cre targets recombination in about 15% of cells within the superchiasmatic nucleus, lateral geniculate nucleus, and

  2. Recombinase-driver rat lines: tools, techniques, and optogenetic application to dopamine-mediated reinforcement.

    Science.gov (United States)

    Witten, Ilana B; Steinberg, Elizabeth E; Lee, Soo Yeun; Davidson, Thomas J; Zalocusky, Kelly A; Brodsky, Matthew; Yizhar, Ofer; Cho, Saemi L; Gong, Shiaoching; Ramakrishnan, Charu; Stuber, Garret D; Tye, Kay M; Janak, Patricia H; Deisseroth, Karl

    2011-12-08

    Currently there is no general approach for achieving specific optogenetic control of genetically defined cell types in rats, which provide a powerful experimental system for numerous established neurophysiological and behavioral paradigms. To overcome this challenge we have generated genetically restricted recombinase-driver rat lines suitable for driving gene expression in specific cell types, expressing Cre recombinase under the control of large genomic regulatory regions (200-300 kb). Multiple tyrosine hydroxylase (Th)::Cre and choline acetyltransferase (Chat)::Cre lines were produced that exhibited specific opsin expression in targeted cell types. We additionally developed methods for utilizing optogenetic tools in freely moving rats and leveraged these technologies to clarify the causal relationship between dopamine (DA) neuron firing and positive reinforcement, observing that optical stimulation of DA neurons in the ventral tegmental area (VTA) of Th::Cre rats is sufficient to support vigorous intracranial self-stimulation (ICSS). These studies complement existing targeting approaches by extending the generalizability of optogenetics to traditionally non-genetically-tractable but vital animal models. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Tamoxifen-independent recombination in the RIP-CreER mouse.

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    Yanmei Liu

    Full Text Available BACKGROUND: The inducible Cre-lox system is a valuable tool to study gene function in a spatial and time restricted fashion in mouse models. This strategy relies on the limited background activity of the modified Cre recombinase (CreER in the absence of its inducer, the competitive estrogen receptor ligand, tamoxifen. The RIP-CreER mouse (Tg (Ins2-cre/Esr1 1Dam is among the few available β-cell specific CreER mouse lines and thus it has been often used to manipulate gene expression in the insulin-producing cells of the endocrine pancreas. PRINCIPAL FINDINGS: Here, we report the detection of tamoxifen-independent Cre activity as early as 2 months of age in RIP-CreER mice crossed with three distinct reporter strains. SIGNIFICANCE: Evidence of Cre-mediated recombination of floxed alleles even in the absence of tamoxifen administration should warrant cautious use of this mouse for the study of pancreatic β-cells.

  4. Generation of Elf5-Cre knockin mouse strain for trophoblast-specific gene manipulation.

    Science.gov (United States)

    Kong, Shuangbo; Liang, Guixian; Tu, Zhaowei; Chen, Dunjin; Wang, Haibin; Lu, Jinhua

    2018-04-01

    Placental development is a complex and highly controlled process during which trophoblast stem cells differentiate to various trophoblast subtypes. The early embryonic death of systemic gene knockout models hampers the investigation of these genes that might play important roles during placentation. A trophoblast specific Cre mouse model would be of great help for dissecting out the potential roles of these genes during placental development. For this purpose, we generate a transgenic mouse with the Cre recombinase inserted into the endogenous locus of Elf5 gene that is expressed specifically in placental trophoblast cells. To analyze the specificity and efficiency of Cre recombinase activity in Elf5-Cre mice, we mated Elf5-Cre mice with Rosa26 mT/mG reporter mice, and found that Elf5-Cre transgene is expressed specifically in the trophoectoderm as early as embryonic day 4.5 (E4.5). By E12.5, the activity of Elf5-Cre transgene was detected exclusively in all derivatives of trophoblast lineages, including spongiotrophoblast, giant cells, and labyrinth trophoblasts. In addition, Elf5-Cre transgene was also active during spermatogenesis, from spermatids to mature sperms, which is consistent with the endogenous Elf5 expression in testis. Collectively, our results provide a unique tool to delete specific genes selectively and efficiently in trophoblast lineage during placentation. © 2018 Wiley Periodicals, Inc.

  5. Contemporary zebrafish transgenesis with Tol2 and application for Cre/lox recombination experiments.

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    Felker, A; Mosimann, C

    2016-01-01

    Spatiotemporal transgene regulation by transgenic DNA recombinases is a central tool for reverse genetics in multicellular organisms, with excellent applications for misexpression and lineage tracing experiments. One of the most widespread technologies for this purpose is Cre recombinase-controlled lox site recombination that is attracting increasing interest in the zebrafish field. Tol2-mediated zebrafish transgenesis provides a stable platform to integrate lox cassette transgenes, while the amenability of the zebrafish embryo to drug treatments makes the model an ideal candidate for tamoxifen-inducible CreERT2 experiments. In addition, advanced transgenesis technologies such as phiC31 or CRISPR-Cas9-based knock-ins are even further promoting zebrafish transgenesis for Cre/lox applications. In this chapter, we will first introduce the basics of Cre/lox methodology, CreERT2 regulation by tamoxifen, as well as the utility of Tol2 and other contemporary transgenesis techniques for Cre/lox experiments. We will then outline in detail practical experimental steps for efficient transgenesis toward the creation of single-insertion transgenes and will introduce protocols for 4-hydroxytamoxifen-mediated CreERT2 induction to perform spatiotemporal lox transgene regulation experiments in zebrafish embryos. Last, we will discuss advanced experimental applications of Cre/lox beyond traditional lineage tracing approaches. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Fshb-iCre mice are efficient and specific Cre deleters for the gonadotrope lineage.

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    Wang, Huizhen; Hastings, Richard; Miller, William L; Kumar, T Rajendra

    2016-01-05

    Genetic analysis of development and function of the gonadotrope cell lineage within mouse anterior pituitary has been greatly facilitated by at least three currently available Cre strains in which Cre was either knocked into the Gnrhr locus or expressed as a transgene from Cga and Lhb promoters. However, in each case there are some limitations including CRE expression in thyrotropes within pituitary or ectopic expression outside of pituitary, for example in some populations of neurons or gonads. Hence, these Cre strains often pose problems with regard to undesirable deletion of alleles in non-gonadotrope cells, fertility and germline transmission of mutant alleles. Here, we describe generation and characterization of a new Fshb-iCre deleter strain using 4.7 kb of ovine Fshb promoter regulatory sequences driving iCre expression exclusively in the gonadotrope lineage within anterior pituitary. Fshb-iCre mice develop normally, display no ectopic CRE expression in gonads and are fertile. When crossed onto a loxP recombination-mediated red to green color switch reporter mouse genetic background, in vivo CRE recombinase activity is detectable in gonadotropes at more than 95% efficiency and the GFP-tagged gonadotropes readily purified by fluorescence activated cell sorting. We demonstrate the applicability of this Fshb-iCre deleter strain in a mouse model in which Dicer is efficiently and selectively deleted in gonadotropes. We further show that loss of DICER-dependent miRNAs in gonadotropes leads to profound suppression of gonadotropins resulting in male and female infertility. Thus, Fshb-iCre mice serve as a new genetic tool to efficiently manipulate gonadotrope-specific gene expression in vivo. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Cre-expressing neurons in the cortical white matter of Ntsr1-Cre GN220 mice.

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    Sundberg, Sofie C; Granseth, Björn

    2018-03-23

    Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population. The other half seems to be a distinct white matter (WM) neuron sub-population that we estimate to constitute 2-4% of the total cortical Cre-expressing population. Staining for the neuronal marker Neuronal nuclei (NeuN) revealed that about 15-40% of WM neurons are Cre-expressing. Thus, the potential contribution from WM neurons needs to be considered when interpreting the results from experiments using the Ntsr1-Cre GN220 mouse for investigating corticothalamic neuronal function. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Lactation Defect in a Widely Used MMTV-Cre Transgenic Line of Mice

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    Yuan, Taichang; Wang, Yongping; Pao, Lily; Anderson, Steve M.; Gu, Haihua

    2011-01-01

    Background MMTV-Cre mouse lines have played important roles in our understanding about the functions of numerous genes in mouse mammary epithelial cells during mammary gland development and tumorigenesis. However, numerous studies have not included MMTV-Cre mice as controls, and many investigators have not indicated which of the different MMTV-Cre founder lines were used in their studies. Here, we describe a lactation defect that severely limits the use of one of the most commonly used MMTV-Cre founder lines. Methodology/Principal Findings To explore the role of protein tyrosine phosphatase Shp1 in mammary gland development, mice bearing the floxed Shp1 gene were crossed with MMTV-Cre mice and mammary gland development was examined by histological and biochemical techniques, while lactation competency was assessed by monitoring pup growth. Surprisingly, both the Shp1fl/+;MMTV-Cre and MMTV-Cre female mice displayed a severe lactation defect when compared to the Shp1 fl/+ control mice. Histological and biochemical analyses reveal that female mice expressing the MMTV-Cre transgene, either alone or in combination with floxed genes, exhibit defects in lobuloalveolar expansion, presence of large cytoplasmic lipid droplets in luminal alveolar epithelial cells postpartum, and precocious induction of involution. Using a PCR-based genotyping method, the three different founder lines can be distinguished, and we determined that the MMTV-Cre line A, the most widely used MMTV-Cre founder line, exhibits a profound lactation defect that limits its use in studies on mammary gland development. Conclusions/Significance The identification of a lactation defect in the MMTV-Cre line A mice indicates that investigators must use MMTV-Cre alone mice as control in studies that utilize Cre recombinase to excise genes of interest from mammary epithelial cells. Our results also suggest that previous results obtained in studies using the MMTV-Cre line A line should be re-evaluated if the

  9. Application of a novel regulatable Cre recombinase system to define the role of liver and gut metabolism in drug oral bioavailability.

    Science.gov (United States)

    Henderson, Colin J; McLaughlin, Lesley A; Osuna-Cabello, Maria; Taylor, Malcolm; Gilbert, Ian; McLaren, Aileen W; Wolf, C Roland

    2015-02-01

    The relative contribution of hepatic compared with intestinal oxidative metabolism is a crucial factor in drug oral bioavailability and therapeutic efficacy. Oxidative metabolism is mediated by the cytochrome P450 mono-oxygenase system to which cytochrome P450 reductase (POR) is the essential electron donor. In order to study the relative importance of these pathways in drug disposition, we have generated a novel mouse line where Cre recombinase is driven off the endogenous Cyp1a1 gene promoter; this line was then crossed on to a floxed POR mouse. A 40 mg/kg dose of the Cyp1a1 inducer 3-methylcholanthrene (3MC) eliminated POR expression in both liver and small intestine, whereas treatment at 4 mg/kg led to a more targeted deletion in the liver. Using this approach, we have studied the pharmacokinetics of three probe drugs--paroxetine, midazolam, nelfinavir--and show that intestinal metabolism is a determinant of oral bioavailability for the two latter compounds. The Endogenous Reductase Locus (ERL) mouse represents a significant advance on previous POR deletion models as it allows direct comparison of hepatic and intestinal effects on drug and xenobiotic clearance using lower doses of a single Cre inducing agent, and in addition minimizes any cytotoxic effects, which may compromise interpretation of the experimental data.

  10. A photoactivatable Cre-loxP recombination system for optogenetic genome engineering.

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    Kawano, Fuun; Okazaki, Risako; Yazawa, Masayuki; Sato, Moritoshi

    2016-12-01

    Genome engineering techniques represented by the Cre-loxP recombination system have been used extensively for biomedical research. However, powerful and useful techniques for genome engineering that have high spatiotemporal precision remain elusive. Here we develop a highly efficient photoactivatable Cre recombinase (PA-Cre) to optogenetically control genome engineering in vivo. PA-Cre is based on the reassembly of split Cre fragments by light-inducible dimerization of the Magnet system. PA-Cre enables sharp induction (up to 320-fold) of DNA recombination and is efficiently activated even by low-intensity illumination (∼0.04 W m -2 ) or short periods of pulsed illumination (∼30 s). We demonstrate that PA-Cre allows for efficient DNA recombination in an internal organ of living mice through noninvasive external illumination using a LED light source. The present PA-Cre provides a powerful tool to greatly facilitate optogenetic genome engineering in vivo.

  11. A new Cre driver mouse line, Tcf21/Pod1-Cre, targets metanephric mesenchyme.

    Directory of Open Access Journals (Sweden)

    Yoshiro Maezawa

    Full Text Available Conditional gene targeting in mice has provided great insight into the role of gene function in kidney development and disease. Although a number of Cre-driver mouse strains already exist for the kidney, development of additional strains with unique expression patterns is needed. Here we report the generation and validation of a Tcf21/Pod1-Cre driver strain that expresses Cre recombinase throughout the condensing and stromal mesenchyme of developing kidneys and in their derivatives including epithelial components of the nephron and interstitial cells. To test the efficiency of this line, we crossed it to mice transgenic for either loss or gain of function β-catenin conditional alleles. Mice with deletion of β-catenin from Tcf21-expressing cells are born with hypoplastic kidneys, hydroureters and hydronephrosis. By contrast, Tcf21-Cre driven gain of function for β-catenin in mice results in fused midline kidneys and hypoplastic kidneys. Finally, we report the first renal mesenchymal deletion of Patched1 (Ptch1, the receptor for sonic hedgehog (Shh, which results in renal cysts demonstrating a functional role of Shh signaling pathway in renal cystogensis. In summary, we report the generation and validation of a new Cre driver strain that provides robust excision in metanephric mesenchyme.

  12. Enzymatic engineering of the porcine genome with transposons and recombinases

    Directory of Open Access Journals (Sweden)

    Carlson Daniel F

    2007-07-01

    Full Text Available Abstract Background Swine is an important agricultural commodity and biomedical model. Manipulation of the pig genome provides opportunity to improve production efficiency, enhance disease resistance, and add value to swine products. Genetic engineering can also expand the utility of pigs for modeling human disease, developing clinical treatment methodologies, or donating tissues for xenotransplantation. Realizing the full potential of pig genetic engineering requires translation of the complete repertoire of genetic tools currently employed in smaller model organisms to practical use in pigs. Results Application of transposon and recombinase technologies for manipulation of the swine genome requires characterization of their activity in pig cells. We tested four transposon systems- Sleeping Beauty, Tol2, piggyBac, and Passport in cultured porcine cells. Transposons increased the efficiency of DNA integration up to 28-fold above background and provided for precise delivery of 1 to 15 transgenes per cell. Both Cre and Flp recombinase were functional in pig cells as measured by their ability to remove a positive-negative selection cassette from 16 independent clones and over 20 independent genomic locations. We also demonstrated a Cre-dependent genetic switch capable of eliminating an intervening positive-negative selection cassette and activating GFP expression from episomal and genome-resident transposons. Conclusion We have demonstrated for the first time that transposons and recombinases are capable of mobilizing DNA into and out of the porcine genome in a precise and efficient manner. This study provides the basis for developing transposon and recombinase based tools for genetic engineering of the swine genome.

  13. Supporting conditional mouse mutagenesis with a comprehensive cre characterization resource

    Science.gov (United States)

    Heffner, Caleb S.; Herbert Pratt, C.; Babiuk, Randal P.; Sharma, Yashoda; Rockwood, Stephen F.; Donahue, Leah R.; Eppig, Janan T.; Murray, Stephen A.

    2012-01-01

    Full realization of the value of the loxP-flanked alleles generated by the International Knockout Mouse Consortium will require a large set of well-characterized cre-driver lines. However, many cre driver lines display excision activity beyond the intended tissue or cell type, and these data are frequently unavailable to the potential user. Here we describe a high-throughput pipeline to extend characterization of cre driver lines to document excision activity in a wide range of tissues at multiple time points and disseminate these data to the scientific community. Our results show that the majority of cre strains exhibit some degree of unreported recombinase activity. In addition, we observe frequent mosaicism, inconsistent activity and parent-of-origin effects. Together, these results highlight the importance of deep characterization of cre strains, and provide the scientific community with a critical resource for cre strain information. PMID:23169059

  14. Characterization of intravitreally delivered capsid mutant AAV2-Cre vector to induce tissue-specific mutations in murine retinal ganglion cells.

    Science.gov (United States)

    Langouet-Astrie, Christophe J; Yang, Zhiyong; Polisetti, Sraavya M; Welsbie, Derek S; Hauswirth, William W; Zack, Donald J; Merbs, Shannath L; Enke, Raymond A

    2016-10-01

    Targeted expression of Cre recombinase in murine retinal ganglion cells (RGCs) by viral vector is an effective strategy for creating tissue-specific gene knockouts for investigation of genetic contribution to RGC degeneration associated with optic neuropathies. Here we characterize dosage, efficacy and toxicity for sufficient intravitreal delivery of a capsid mutant Adeno-associated virus 2 (AAV2) vector encoding Cre recombinase. Wild type and Rosa26 (R26) LacZ mice were intravitreally injected with capsid mutant AAV2 viral vectors. Murine eyes were harvested at intervals ranging from 2 weeks to 15 weeks post-injection and were assayed for viral transduction, transgene expression and RGC survival. 10(9) vector genomes (vg) were sufficient for effective in vivo targeting of murine ganglion cell layer (GCL) retinal neurons. Transgene expression was observed as early as 2 weeks post-injection of viral vectors and persisted to 11 weeks. Early expression of Cre had no significant effect on RGC survival, while significant RGC loss was detected beginning 5 weeks post-injection. Early expression of viral Cre recombinase was robust, well-tolerated and predominantly found in GCL neurons suggesting this strategy can be effective in short-term RGC-specific mutation studies in experimental glaucoma models such as optic nerve crush and transection experiments. RGC degeneration with Cre expression for more than 4 weeks suggests that Cre toxicity is a limiting factor for targeted mutation strategies in RGCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Intein-mediated Cre protein assembly for transgene excision in hybrid progeny of transgenic Arabidopsis.

    Science.gov (United States)

    Ge, Jia; Wang, Lijun; Yang, Chen; Ran, Lingyu; Wen, Mengling; Fu, Xianan; Fan, Di; Luo, Keming

    2016-10-01

    An approach for restoring recombination activity of complementation split-Cre was developed to excise the transgene in hybrid progeny of GM crops. Growing concerns about the biosafety of genetically modified (GM) crops has currently become a limited factor affecting the public acceptance. Several approaches have been developed to generate selectable-marker-gene-free GM crops. However, no strategy was reported to be broadly applicable to hybrid crops. Previous studies have demonstrated that complementation split-Cre recombinase restored recombination activity in transgenic plants. In this study, we found that split-Cre mediated by split-intein Synechocystis sp. DnaE had high recombination efficiency when Cre recombinase was split at Asp232/Asp233 (866 bp). Furthermore, we constructed two plant expression vectors, pCA-NCre-In and pCA-Ic-CCre, containing NCre866-In and Ic-CCre866 fragments, respectively. After transformation, parent lines of transgenic Arabidopsis with one single copy were generated and used for hybridization. The results of GUS staining demonstrated that the recombination activity of split-Cre could be reassembled in these hybrid progeny of transgenic plants through hybridization and the foreign genes flanked by two loxP sites were efficiently excised. Our strategy may provide an effective approach for generating the next generation of GM hybrid crops without biosafety concerns.

  16. Real-time single-molecule tethered particle motion experiments reveal the kinetics and mechanisms of Cre-mediated site-specific recombination

    Science.gov (United States)

    Fan, Hsiu-Fang

    2012-01-01

    Tyrosine family recombinases (YRs) are widely utilized in genome engineering systems because they can easily direct DNA rearrangement. Cre recombinases, one of the most commonly used types of YRs, catalyze site-specific recombination between two loxP sites without the need for high-energy cofactors, other accessory proteins or a specific DNA target sequence between the loxP sites. Previous structural, analytical ultracentrifuge and electrophoretic analyses have provided details of the reaction kinetics and mechanisms of Cre recombinase activity; whether there are reaction intermediates or side pathways involved has been left unaddressed. Using tethered particle motion (TPM), the Cre-mediated site-specific recombination process has been delineated, from beginning to end, at the single-molecule level, including the formation of abortive complexes and wayward complexes blocking inactive nucleoprotein complexes from entering the recombination process. Reversibility in the strand-cleavage/-ligation process and the formation of a thermally stable Holliday junction intermediate were observed within the Cre-mediated site-specific recombination process. Rate constants for each elementary step, which explain the overall reaction outcomes under various conditions, were determined. Taking the findings of this study together, they demonstrate the potential of single-molecule methodology as an alternative approach for exploring reaction mechanisms in detail. PMID:22467208

  17. Cre-expressing neurons in visual cortex of Ntsr1-Cre GN220 mice are corticothalamic and are depolarized by acetylcholine.

    Science.gov (United States)

    Sundberg, Sofie Charlotte; Lindström, Sarah Helen; Sanchez, Gonzalo Manuel; Granseth, Björn

    2018-01-01

    The Ntsr1-Cre GN220 mouse expresses Cre-recombinase in corticothalamic (CT) neurons in neocortical layer 6. It is not known if the other major types of pyramidal neurons in this layer also express this enzyme. By electrophysiological recordings in slices and histological analysis of the uptake of retrogradely transported beads we show that Cre-positive neurons are CT and not corticocortical or corticoclaustral types. Furthermore, we show that Ntsr1-Cre-positive cells are immuno-positive for the nuclear transcription factor Forkhead box protein P2 (FoxP2). We conclude that Cre-expression is limited to a specific type of pyramidal neuron: CT. However, it appears as not all CT neurons are Cre-expressing; there are indications that the penetrance of the gene is about 90%. We demonstrate the utility of assigning a specific identity to individual neurons by determining that the CT neurons are potently modulated by acetylcholine acting on both nicotinic and muscarinic acetylcholine receptors. These results corroborate the suggested function of these neurons in regulating the gain of thalamocortical transfer of sensory information depending on attentional demand and state of arousal. © 2017 Wiley Periodicals, Inc.

  18. Cre Activated and Inactivated Recombinant Adeno-Associated Viral Vectors for Neuronal Anatomical Tracing or Activity Manipulation.

    Science.gov (United States)

    Saunders, Arpiar; Sabatini, Bernardo L

    2015-07-01

    Recombinant adeno-associated viruses (rAAVs) transcriptionally activated by Cre recombinase (Cre-On) are powerful tools for determining the anatomy and function of genetically defined neuronal types in transgenic Cre driver mice. Here we describe how rAAVs transcriptionally inactivated by Cre (Cre-Off) can be used in conjunction with Cre-On rAAVs or genomic Cre-reporter alleles to study brain circuits. Intracranial injection of Cre-On/Cre-Off rAAVs into spatially intermingled Cre(+) and Cre(-) neurons allows these populations to be differentially labeled or manipulated within individual animals. This comparison helps define the unique properties of Cre(+) neurons, highlighting the specialized role they play in their constituent brain circuits. This protocol touches on the conceptual and experimental background of Cre-Off rAAV systems, including caveats and methods of validation. Copyright © 2015 John Wiley & Sons, Inc.

  19. Mef2c-F10N enhancer driven β-galactosidase (LacZ) and Cre recombinase mice facilitate analyses of gene function and lineage fate in neural crest cells.

    Science.gov (United States)

    Aoto, Kazushi; Sandell, Lisa L; Butler Tjaden, Naomi E; Yuen, Kobe C; Watt, Kristin E Noack; Black, Brian L; Durnin, Michael; Trainor, Paul A

    2015-06-01

    Neural crest cells (NCC) comprise a multipotent, migratory stem cell and progenitor population that gives rise to numerous cell and tissue types within a developing embryo, including craniofacial bone and cartilage, neurons and glia of the peripheral nervous system, and melanocytes within the skin. Here we describe two novel stable transgenic mouse lines suitable for lineage tracing and analysis of gene function in NCC. Firstly, using the F10N enhancer of the Mef2c gene (Mef2c-F10N) linked to LacZ, we generated transgenic mice (Mef2c-F10N-LacZ) that express LacZ in the majority, if not all migrating NCC that delaminate from the neural tube. Mef2c-F10N-LacZ then continues to be expressed primarily in neurogenic, gliogenic and melanocytic NCC and their derivatives, but not in ectomesenchymal derivatives. Secondly, we used the same Mef2c-F10N enhancer together with Cre recombinase to generate transgenic mice (Mef2c-F10N-Cre) that can be used to indelibly label, or alter gene function in, migrating NCC and their derivatives. At early stages of development, Mef2c-F10N-LacZ and Mef2c-F10N-Cre label NCC in a pattern similar to Wnt1-Cre mice, with the exception that Mef2c-F10N-LacZ and Mef2c-F10N-Cre specifically label NCC that have delaminated from the neural plate, while premigratory NCC are not labeled. Thus, our Mef2c-F10N-LacZ and Mef2c-F10N-Cre transgenic mice provide new resources for tracing migratory NCC and analyzing gene function in migrating and differentiating NCC independently of NCC formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Cre Recombinase: You Can't Live with It, and You Can't Live Without It.

    Science.gov (United States)

    Le, Yun-Zheng; Zhu, Meili; Anderson, Robert E

    2016-01-01

    The development of conditional gene targeting has greatly advanced our knowledge of human retinal diseases, but issues have arisen related to the use of some Cre-expressing mouse lines. In this article, we discuss potential problems associated with transgenic Cre expression-induced degeneration and alteration of rod photoreceptors and retinal pigment epithelium (RPE). Our strategy for circumventing RPE degeneration by induced transient Cre expression uses a single intravitreal doxycycline injection in a tetracycline-inducible RPE-specific Cre mouse line, which results in productive Cre-mediated recombination efficiently in the RPE. As constitutive expression of Cre in the RPE alters RPE biology, this inducible Cre/lox system provides an opportunity for conditional gene targeting in the RPE, a tissue that is closely related to photoreceptor degeneration, age-related macular degeneration, and diabetic retinopathy.

  1. Prolonged Cre expression driven by the α-myosin heavy chain promoter can be cardiotoxic.

    Science.gov (United States)

    Pugach, Emily K; Richmond, Phillip A; Azofeifa, Joseph G; Dowell, Robin D; Leinwand, Leslie A

    2015-09-01

    Studying the importance of genetic factors in a desired cell type or tissue necessitates the use of precise genetic tools. With the introduction of bacteriophage Cre recombinase/loxP mediated DNA editing and promoter-specific Cre expression, it is feasible to generate conditional knockout mice in which particular genes are disrupted in a cell type-specific manner in vivo. In cardiac myocytes, this is often achieved through α-myosin heavy chain promoter (αMyHC)-driven Cre expression in conjunction with a loxP-site flanked gene of interest. Recent studies in other cell types demonstrate toxicity of Cre expression through induction of DNA damage. However, it is unclear to what extent the traditionally used αMyHC-Cre line [1] may exhibit cardiotoxicity. Further, the genotype of αMyHC-Cre(+/-) is not often included as a control group in cardiac myocyte-specific knockout studies. Here we present evidence that these αMyHC-Cre(+/-) mice show molecular signs of cardiac toxicity by 3months of age and exhibit decreased cardiac function by 6months of age compared to wild-type littermates. Hearts from αMyHC-Cre(+/-) mice also display evidence of fibrosis, inflammation, and DNA damage. Interestingly, some of the early functional changes observed in αMyHC-Cre(+/-) mice are sexually dimorphic. Given the high level of Cre recombinase expression resulting from expression from the αMyHC promoter, we asked if degenerate loxP-like sites naturally exist in the mouse genome and if so, whether they are affected by Cre in the absence of canonical loxP-sites. Using a novel bioinformatics search tool, we identified 619 loxP-like sites with 4 or less mismatches to the canonical loxP-site. 227 sites overlapped with annotated genes and 55 of these genes were expressed in cardiac muscle. Expression of ~26% of the 27 genes tested was disrupted in αMyHC-Cre(+/-) mice indicating potential targeting by Cre. Taken together, these results highlight both the importance of using αMyHC-Cre mice

  2. A non-specific effect associated with conditional transgene expression based on Cre-loxP strategy in mice.

    Directory of Open Access Journals (Sweden)

    Linghua Qiu

    Full Text Available Transgenes flanked by loxP sites have been widely used to generate transgenic mice where the transgene expression can be controlled spatially and temporally by Cre recombinase. Data from this approach has led to important conclusions in cancer, neurodevelopment and neurodegeneration. Using this approach to conditionally express micro RNAs (miRNAs in mice, we found that Cre-mediated recombination in neural progenitor cells caused microcephaly in five of our ten independent transgenic lines. This effect was not associated with the types or the quantity of miRNAs being expressed, nor was it associated with specific target knockdown. Rather, it was correlated with the presence of multiple tandem transgene copies and inverted (head-to-head or tail-to-tail transgene repeats. The presence of these inverted repeats caused a high level of cell death in the ventricular zone of the embryonic brain, where Cre was expressed. Therefore, results from this Cre-loxP approach to generate inducible transgenic alleles must be interpreted with caution and conclusions drawn in previous reports may need reexamination.

  3. Novel recombinant adeno-associated viruses for Cre activated and inactivated transgene expression in neurons

    Science.gov (United States)

    Saunders, Arpiar; Johnson, Caroline A.; Sabatini, Bernardo L.

    2012-01-01

    Understanding the organization of the nervous system requires methods for dissecting the contributions of each component cell type to circuit function. One widely used approach combines genetic targeting of Cre recombinase to specific cell populations with infection of recombinant adeno-associated viruses (rAAVs) whose transgene expression is activated by Cre (“Cre-On”). Distinguishing how the Cre-expressing neurons differ functionally from neighboring Cre-negative neurons requires rAAVs that are inactivated by Cre (“Cre-Off”) and can be used in tandem with Cre-On viruses. Here we introduce two rAAV vectors that are inactivated by Cre and carry different fluorophore and optogenetic constructs. We demonstrate single and dual rAAV systems to achieve Cre-On and Cre-Off expression in spatially-intermingled cell populations of the striatum. Using these systems, we uncovered cryptic genomic interactions that occur between multiple Cre-sensitive rAAVs or between Cre-sensitive rAAVs and somatic Cre-conditional alleles and devised methods to avoid these interactions. Our data highlight both important experimental caveats associated with Cre-dependent rAAV use as well as opportunities for the development of improved rAAVs for gene delivery. PMID:22866029

  4. CRISPR/Cas9-mediated targeting of the Rosa26 locus produces Cre reporter rat strains for monitoring Cre-loxP-mediated lineage tracing.

    Science.gov (United States)

    Ma, Yuanwu; Yu, Lei; Pan, Shuo; Gao, Shan; Chen, Wei; Zhang, Xu; Dong, Wei; Li, Jing; Zhou, Rui; Huang, Lan; Han, Yunlin; Bai, Lin; Zhang, Li; Zhang, Lianfeng

    2017-10-01

    The rat is an important laboratory animal for physiological, toxicological and pharmacological studies. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) is a simple and efficient tool to generate precise genetic modifications in rats, which will promote the accumulation of genetic resources and enable more precise studies of gene function. To monitor Cre-loxP-mediated excision in vivo, we generated a Cre reporter rat strain (Rosa26-imCherry) by knockin of a Cre reporter cassette at the Rosa26 locus using CRISPR/Cas9. Rosa26-imCherry rats exhibited inducible expression of the mCherry cassette (imCherry) using the Cre-loxP system, whereas normal rats exhibited ubiquitous expression of eGFP but not mCherry in the whole body. Injection of adeno-associated virus serotype 9-Cre into the hippocampus and skeletal muscle resulted in mCherry expression in virus-infected cells. Cre-loxP-mediated mCherry expression was then evaluated by crossing Rosa26-imCherry rats with transgenic rats ubiquitously expressing CAG-Cre, heart-specific α-MHC-Cre transgenic rats and liver-specific Alb-Cre knockin rats. Finally, using the established system the expression pattern of Cre driven by two endogenous gene promoters (Wfs1-Cre knockin rat, FabP2-Cre knockin rat) was traced. In summary, we demonstrated excision of the loxP-flanked allele in Rosa26-imCherry rats via activation of mCherry expression in the presence of Cre recombinase. This newly established Rosa26-imCherry rat strain represents a useful tool to facilitate Cre-expression pattern determination and tracing experiments. © 2017 Federation of European Biochemical Societies.

  5. Inducible targeting of CNS astrocytes in Aldh1l1-CreERT2 BAC transgenic mice.

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    Winchenbach, Jan; Düking, Tim; Berghoff, Stefan A; Stumpf, Sina K; Hülsmann, Swen; Nave, Klaus-Armin; Saher, Gesine

    2016-01-01

    Background: Studying astrocytes in higher brain functions has been hampered by the lack of genetic tools for the efficient expression of inducible Cre recombinase throughout the CNS, including the neocortex. Methods: Therefore, we generated BAC transgenic mice, in which CreERT2 is expressed under control of the Aldh1l1 regulatory region. Results: When crossbred to Cre reporter mice, adult Aldh1l1-CreERT2 mice show efficient gene targeting in astrocytes. No such Cre-mediated recombination was detectable in CNS neurons, oligodendrocytes, and microglia. As expected, Aldh1l1-CreERT2 expression was evident in several peripheral organs, including liver and kidney. Conclusions: Taken together, Aldh1l1-CreERT2 mice are a useful tool for studying astrocytes in neurovascular coupling, brain metabolism, synaptic plasticity and other aspects of neuron-glia interactions.

  6. Foxn1[Cre] Expression in the Male Germline.

    Science.gov (United States)

    Shi, Jianjun; Getun, Irina; Torres, Bivian; Petrie, Howard T

    2016-01-01

    Foxn1 (forkhead box N1), also known as the nude gene or winged-helix nude (Whn), is a forkhead transcription factor thought to be restricted to keratinocytes in the skin and thymus. Consistent with this tissue distribution, spontaneous or targeted mutation of Foxn1 results in the absence of both hair and a thymus. Genetic manipulation of the Foxn1 locus thus represents a powerful tool for tissue specific gene control in the skin and thymus, and tools such as Cre recombinase under control of the Foxn1 locus are widely used for this purpose. Unexpectedly, we show that Foxn1[Cre] exhibits unexpected activity in male germ cells, resulting in ubiquitous targeting of loxP-flanked alleles in all tissues in offspring from Foxn1[Cre] expressing male mice. Inheritance of recombined loxP alleles occurs independently of Cre inheritance (i.e., offspring lacking Cre nonetheless exhibit recombined alleles), suggesting that Foxn1[Cre] induced recombination in male germ cells must occur prior to meiosis in diploid germ cells. Together with previously published data, our results show that Foxn1, and alleles under its control, are expressed in the pre-meiotic male germline, revealing a new tool for germline targeting of genes, and raising important concerns for gender selection when using Foxn1 regulatory elements.

  7. Optimizing tamoxifen-inducible Cre/loxp system to reduce tamoxifen effect on bone turnover in long bones of young mice.

    Science.gov (United States)

    Zhong, Zhendong A; Sun, Weihua; Chen, Haiyan; Zhang, Hongliang; Lay, Yu-An E; Lane, Nancy E; Yao, Wei

    2015-12-01

    For tamoxifen-dependent Cre recombinase, also known as CreER recombinase, tamoxifen (TAM) is used to activate the Cre to generate time- and tissue-specific mouse mutants. TAM is a potent CreER system inducer; however, TAM is also an active selective estrogen receptor modulator (SERM) that can influence bone homeostasis. The purpose of this study was to optimize the TAM dose for Cre recombinase activation while minimizing the effects of TAM on bone turnover in young growing mice. To evaluate the effects of TAM on bone turnover and bone mass, 1-month-old wild-type male and female mice were intraperitoneally injected with TAM at 0, 1, 10 or 100mg/kg/day for four consecutive days, or 100, 300 mg/kg/day for one day. The distal femurs were analyzed one month after the last TAM injection by microCT, mechanical test, and surface-based bone histomorphometry. Similar doses of TAM were used in Col1 (2.3 kb)-CreERT2; mT/mG reporter male mice to evaluate the dose-dependent efficacy of Cre-ER activation in bone tissue. A TAM dose of 100 mg/kg × 4 days significantly increased trabecular bone volume/total volume (BV/TV) of the distal femur, femur length, bone strength, and serum bone turnover markers compared to the 0mg control group. In contrast, TAM doses ≤ 10 mg/kg did not significantly change any of these parameters compared to the 0mg group, although a higher bone strength was observed in the 10mg group. Surface-based histomorphometry revealed that the 100mg/kg dose of TAM dose significantly increased trabecular bone formation and decreased periosteal bone formation at 1-week post-TAM treatment. Using the reporter mouse model Col1-CreERT2; mT/mG, we found that 10mg/kg TAM induced Col1-CreERT2 activity in bone at a comparable level to the 100mg/kg dose. TAM treatment at 100mg/kg/day × 4 days significantly affects bone homeostasis, resulting in an anabolic bone effect on trabecular bone in 1-month-old male mice. However, a lower dose of TAM at 10 mg/kg/day × 4 days can

  8. Generation of brain tumours in mice by Cre-mediated recombination of neural progenitors in situ with the tamoxifen metabolite endoxifen

    Directory of Open Access Journals (Sweden)

    Anna Benedykcinska

    2016-02-01

    Full Text Available Targeted cell- or region-specific gene recombination is widely used in the functional analysis of genes implicated in development and disease. In the brain, targeted gene recombination has become a mainstream approach to study neurodegeneration or tumorigenesis. The use of the Cre-loxP system to study tumorigenesis in the adult central nervous system (CNS can be limited, when the promoter (such as GFAP is also transiently expressed during development, which can result in the recombination of progenies of different lineages. Engineering of transgenic mice expressing Cre recombinase fused to a mutant of the human oestrogen receptor (ER allows the circumvention of transient developmental Cre expression by inducing recombination in the adult organism. The recombination of loxP sequences occurs only in the presence of tamoxifen. Systemic administration of tamoxifen can, however, exhibit toxicity and might also recombine unwanted cell populations if the promoter driving Cre expression is active at the time of tamoxifen administration. Here, we report that a single site-specific injection of an active derivative of tamoxifen successfully activates Cre recombinase and selectively recombines tumour suppressor genes in neural progenitor cells of the subventricular zone in mice, and we demonstrate its application in a model for the generation of intrinsic brain tumours.

  9. Generation of brain tumours in mice by Cre-mediated recombination of neural progenitors in situ with the tamoxifen metabolite endoxifen.

    Science.gov (United States)

    Benedykcinska, Anna; Ferreira, Andreia; Lau, Joanne; Broni, Jessica; Richard-Loendt, Angela; Henriquez, Nico V; Brandner, Sebastian

    2016-02-01

    Targeted cell- or region-specific gene recombination is widely used in the functional analysis of genes implicated in development and disease. In the brain, targeted gene recombination has become a mainstream approach to study neurodegeneration or tumorigenesis. The use of the Cre-loxP system to study tumorigenesis in the adult central nervous system (CNS) can be limited, when the promoter (such as GFAP) is also transiently expressed during development, which can result in the recombination of progenies of different lineages. Engineering of transgenic mice expressing Cre recombinase fused to a mutant of the human oestrogen receptor (ER) allows the circumvention of transient developmental Cre expression by inducing recombination in the adult organism. The recombination of loxP sequences occurs only in the presence of tamoxifen. Systemic administration of tamoxifen can, however, exhibit toxicity and might also recombine unwanted cell populations if the promoter driving Cre expression is active at the time of tamoxifen administration. Here, we report that a single site-specific injection of an active derivative of tamoxifen successfully activates Cre recombinase and selectively recombines tumour suppressor genes in neural progenitor cells of the subventricular zone in mice, and we demonstrate its application in a model for the generation of intrinsic brain tumours. © 2016. Published by The Company of Biologists Ltd.

  10. Cre-dependent DNA recombination activates a STING-dependent innate immune response

    Science.gov (United States)

    Pépin, Geneviève; Ferrand, Jonathan; Höning, Klara; Jayasekara, W. Samantha N.; Cain, Jason E.; Behlke, Mark A.; Gough, Daniel J.; G. Williams, Bryan R.; Hornung, Veit

    2016-01-01

    Abstract Gene-recombinase technologies, such as Cre/loxP-mediated DNA recombination, are important tools in the study of gene function, but have potential side effects due to damaging activity on DNA. Here we show that DNA recombination by Cre instigates a robust antiviral response in mammalian cells, independent of legitimate loxP recombination. This is due to the recruitment of the cytosolic DNA sensor STING, concurrent with Cre-dependent DNA damage and the accumulation of cytoplasmic DNA. Importantly, we establish a direct interplay between this antiviral response and cell–cell interactions, indicating that low cell densities in vitro could be useful to help mitigate these effects of Cre. Taking into account the wide range of interferon stimulated genes that may be induced by the STING pathway, these results have broad implications in fields such as immunology, cancer biology, metabolism and stem cell research. Further, this study sets a precedent in the field of gene-engineering, possibly applicable to other enzymatic-based genome editing technologies. PMID:27166376

  11. Neuropilin-2 genomic elements drive cre recombinase expression in primitive blood, vascular and neuronal lineages.

    Science.gov (United States)

    Wiszniak, Sophie; Scherer, Michaela; Ramshaw, Hayley; Schwarz, Quenten

    2015-11-01

    We have established a novel Cre mouse line, using genomic elements encompassing the Nrp2 locus, present within a bacterial artificial chromosome clone. By crossing this Cre driver line to R26R LacZ reporter mice, we have documented the temporal expression and lineage traced tissues in which Cre is expressed. Nrp2-Cre drives expression in primitive blood cells arising from the yolk sac, venous and lymphatic endothelial cells, peripheral sensory ganglia, and the lung bud. This mouse line will provide a new tool to researchers wishing to study the development of various tissues and organs in which this Cre driver is expressed, as well as allow tissue-specific knockout of genes of interest to study protein function. This work also presents the first evidence for expression of Nrp2 protein in a mesodermal progenitor with restricted hematopoietic potential, which will significantly advance the study of primitive erythropoiesis. genesis 53:709-717, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  12. Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites

    Science.gov (United States)

    Dorà, Natalie J.; Collinson, J. Martin; Hill, Robert E.; West, John D.

    2014-01-01

    Eye phenotypes were investigated in Le-CreTg/−; Pax6fl/+ mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6+/− eye phenotypes, hemizygous Le-CreTg/− and heterozygous Pax6fl/+mice were crossed onto the CBA/Ca genetic background. After the Le-Cre transgene had been backcrossed to CBA/Ca for seven generations, significant eye abnormalities occurred in some hemizygous Le-CreTg/−; Pax6+/+ controls (without a floxed Pax6fl allele) as well as experimental Le-CreTg/−; Pax6fl/+ mice. However, no abnormalities were seen in Le-Cre−/−; Pax6fl/+ or Le-Cre−/−; Pax6+/+ controls (without the Le-Cre transgene). The severity and frequency of the eye abnormalities in Le-CreTg/−; Pax6+/+ control mice diminished after backcrossing Le-CreTg/− mice to the original FVB/N strain for two generations, showing that the effect was reversible. This genetic background effect suggests that the eye abnormalities are a consequence of an interaction between the Le-Cre transgene and alleles of unknown modifier genes present in certain genetic backgrounds. The abnormalities were also ameliorated by introducing additional Pax6 gene copies on a CBA/Ca background, suggesting involvement of Pax6 depletion in Le-CreTg/−; Pax6+/+ mice rather than direct action of Cre recombinase on cryptic pseudo-loxP sites. One possibility is that expression of Cre recombinase from the Pax6-Le regulatory sequences in the Le-Cre transgene depletes cofactors required for endogenous Pax6 gene expression. Our observation that eye abnormalities can occur in hemizygous Le-CreTg/−; Pax6+/+ mice, in the absence of a floxed allele, demonstrates the importance of including all the relevant genetic controls in Cre-loxP experiments. PMID:25272013

  13. Phenotypically silent Cre recombination within the postnatal ventricular conduction system.

    Science.gov (United States)

    Bhattacharyya, Samadrita; Bhakta, Minoti; Munshi, Nikhil Vilas

    2017-01-01

    The cardiac conduction system (CCS) is composed of specialized cardiomyocytes that initiate and maintain cardiac rhythm. Any perturbation to the normal sequence of electrical events within the heart can result in cardiac arrhythmias. To understand how cardiac rhythm is established at the molecular level, several genetically modified mouse lines expressing Cre recombinase within specific CCS compartments have been created. In general, Cre driver lines have been generated either by homologous recombination of Cre into an endogenous locus or Cre expression driven by a randomly inserted transgene. However, haploinsufficiency of the endogenous gene compromises the former approach, while position effects negatively impact the latter. To address these limitations, we generated a Cre driver line for the ventricular conduction system (VCS) that preserves endogenous gene expression by targeting the Contactin2 (Cntn2) 3' untranslated region (3'UTR). Here we show that Cntn23'UTR-IRES-Cre-EGFP/+ mice recombine floxed alleles within the VCS and that Cre expression faithfully recapitulates the spatial distribution of Cntn2 within the heart. We further demonstrate that Cre expression initiates after birth with preservation of native Cntn2 protein. Finally, we show that Cntn23'UTR-IRES-Cre-EGFP/+ mice maintain normal cardiac mechanical and electrical function. Taken together, our results establish a novel VCS-specific Cre driver line without the adverse consequences of haploinsufficiency or position effects. We expect that our new mouse line will add to the accumulating toolkit of CCS-specific mouse reagents and aid characterization of the cell-autonomous molecular circuitry that drives VCS maintenance and function.

  14. Age- and Gene-Dosage–Dependent Cre-Induced Abnormalities in the Retinal Pigment Epithelium

    Science.gov (United States)

    He, Lizhi; Marioutina, Mariya; Dunaief, Joshua L.; Marneros, Alexander G.

    2015-01-01

    To conditionally inactivate genes in the retinal pigment epithelium (RPE) transgenic mouse strains have been developed, in which Cre recombinase (Cre) expression is driven by an RPE-specific gene promoter. The RPE is a quiescent epithelium, and continuous expression of Cre could affect its function. Here, we tested the hypothesis that continuous postnatal Cre expression in the RPE may lead to cellular abnormalities, which may depend on both age and Cre gene dosage. We therefore examined the eyes of homozygous and heterozygous VMD2-Cre mice at various ages. In VMD2-Cre heterozygous mice variable progressive age-dependent RPE abnormalities were noticed, including attenuation of phalloidin and cytoplasmic active β-catenin staining, reduced cell size, and loss of the typical honeycomb pattern of RPE morphology in those RPE cells that stained for Cre. These morphological RPE abnormalities were not noticed in Cre-negative RPE cells in VMD2-Cre or age-matched control mice. In addition, an abnormal number and morphology of cell nuclei were noticed in a subset of Cre-expressing RPE cells in aged heterozygous VMD2-Cre mice, whereas more severe nuclear abnormalities were observed already in young homozygous VMD2-Cre mice. Thus, continuous postnatal expression of Cre causes abnormalities in the RPE in an age- and Cre gene dosage-dependent manner, which needs to be considered in the interpretation of gene targeting studies in the RPE. PMID:24854863

  15. Preserved dopaminergic homeostasis and dopamine-related behaviour in hemizygous TH-Cre mice.

    Science.gov (United States)

    Runegaard, Annika H; Jensen, Kathrine L; Fitzpatrick, Ciarán M; Dencker, Ditte; Weikop, Pia; Gether, Ulrik; Rickhag, Mattias

    2017-01-01

    Cre-driver mouse lines have been extensively used as genetic tools to target and manipulate genetically defined neuronal populations by expression of Cre recombinase under selected gene promoters. This approach has greatly advanced neuroscience but interpretations are hampered by the fact that most Cre-driver lines have not been thoroughly characterized. Thus, a phenotypic characterization is of major importance to reveal potential aberrant phenotypes prior to implementation and usage to selectively inactivate or induce transgene expression. Here, we present a biochemical and behavioural assessment of the dopaminergic system in hemizygous tyrosine hydroxylase (TH)-Cre mice in comparison to wild-type (WT) controls. Our data show that TH-Cre mice display preserved dopaminergic homeostasis with unaltered levels of TH and dopamine as well as unaffected dopamine turnover in striatum. TH-Cre mice also show preserved dopamine transporter expression and function supporting sustained dopaminergic transmission. In addition, TH-Cre mice demonstrate normal responses in basic behavioural paradigms related to dopaminergic signalling including locomotor activity, reward preference and anxiolytic behaviour. Our results suggest that TH-Cre mice represent a valid tool to study the dopamine system, though careful characterization must always be performed to prevent false interpretations following Cre-dependent transgene expression and manipulation of selected neuronal pathways. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  16. Heterogeneous transgene expression in the retinas of the TH-RFP, TH-Cre, TH-BAC-Cre and DAT-Cre mouse lines.

    Science.gov (United States)

    Vuong, H E; Pérez de Sevilla Müller, L; Hardi, C N; McMahon, D G; Brecha, N C

    2015-10-29

    Transgenic mouse lines are essential tools for understanding the connectivity, physiology and function of neuronal circuits, including those in the retina. This report compares transgene expression in the retina of a tyrosine hydroxylase (TH)-red fluorescent protein (RFP) mouse line with three catecholamine-related Cre recombinase mouse lines [TH-bacterial artificial chromosome (BAC)-, TH-, and dopamine transporter (DAT)-Cre] that were crossed with a ROSA26-tdTomato reporter line. Retinas were evaluated and immunostained with commonly used antibodies including those directed to TH, GABA and glycine to characterize the RFP or tdTomato fluorescent-labeled amacrine cells, and an antibody directed to RNA-binding protein with multiple splicing to identify ganglion cells. In TH-RFP retinas, types 1 and 2 dopamine (DA) amacrine cells were identified by their characteristic cellular morphology and type 1 DA cells by their expression of TH immunoreactivity. In the TH-BAC-, TH-, and DAT-tdTomato retinas, less than 1%, ∼ 6%, and 0%, respectively, of the fluorescent cells were the expected type 1 DA amacrine cells. Instead, in the TH-BAC-tdTomato retinas, fluorescently labeled AII amacrine cells were predominant, with some medium diameter ganglion cells. In TH-tdTomato retinas, fluorescence was in multiple neurochemical amacrine cell types, including four types of polyaxonal amacrine cells. In DAT-tdTomato retinas, fluorescence was in GABA immunoreactive amacrine cells, including two types of bistratified and two types of monostratified amacrine cells. Although each of the Cre lines was generated with the intent to specifically label DA cells, our findings show a cellular diversity in Cre expression in the adult retina and indicate the importance of careful characterization of transgene labeling patterns. These mouse lines with their distinctive cellular labeling patterns will be useful tools for future studies of retinal function and visual processing. Published by Elsevier

  17. The cre-inducer doxycycline lowers cytokine and chemokine transcript levels in the gut of mice

    DEFF Research Database (Denmark)

    Hansen, Axel Kornerup; Malm, Sara Astrup; Metzdorff, Stine B.

    2017-01-01

    The antibiotic doxycycline is used as an inducer of recombinase (cre)-based conditional gene knockout in mice, which is a common tool to show the effect of disrupted gene functions only in one period of a research animal’s life. However, other types of such antibiotics have been shown to have...

  18. Split-Cre complementation restores combination activity on transgene excision in hair roots of transgenic tobacco.

    Directory of Open Access Journals (Sweden)

    Mengling Wen

    Full Text Available The Cre/loxP system is increasingly exploited for genetic manipulation of DNA in vitro and in vivo. It was previously reported that inactive ''split-Cre'' fragments could restore Cre activity in transgenic mice when overlapping co-expression was controlled by two different promoters. In this study, we analyzed recombination activities of split-Cre proteins, and found that no recombinase activity was detected in the in vitro recombination reaction in which only the N-terminal domain (NCre of split-Cre protein was expressed, whereas recombination activity was obtained when the C-terminal (CCre or both NCre and CCre fragments were supplied. We have also determined the recombination efficiency of split-Cre proteins which were co-expressed in hair roots of transgenic tobacco. No Cre recombination event was observed in hair roots of transgenic tobacco when the NCre or CCre genes were expressed alone. In contrast, an efficient recombination event was found in transgenic hairy roots co-expressing both inactive split-Cre genes. Moreover, the restored recombination efficiency of split-Cre proteins fused with the nuclear localization sequence (NLS was higher than that of intact Cre in transgenic lines. Thus, DNA recombination mediated by split-Cre proteins provides an alternative method for spatial and temporal regulation of gene expression in transgenic plants.

  19. Activation Kinetics and Off-Target Effects of Thymus-Initiated Cre Transgenes

    Science.gov (United States)

    Shi, Jianjun; Petrie, Howard T.

    2012-01-01

    The bacteriophage enzyme Cre is a site-specific recombinase widely used to delete loxP-flanked DNA sequences in lineage-specific fashion. Several mouse lines that direct Cre expression to lymphoid progenitors in the thymus have been established, but a side-by-side comparison of when they first become active, and/or their relative efficiency at various developmental stages, has been lacking. In this study, we evaluated these in four common Cre transgenic strains with thymus-initiated promoters (Lck, Cd2, or Cd4). We found that while all of them eventually labeled nearly all thymocytes, their kinetics were dramatically different, and other than Cd4[Cre], did not faithfully recapitulate the expression pattern of the corresponding endogenous gene. Perhaps even more importantly, while thymuses from some strains compared favorably to thymuses from control (Cre-negative) mice, we found that Cre expression could also result in off-target effects, including moderate to severe decreases in thymic cellularity. These effects occurred in the absence of loxP-flanked DNA target genes, and were dose and copy number dependent. Loss of cellularity was attributable to a specific decrease in CD4+8+ immature cells, and corresponds to an increased rate of programmed cell death. In addition to a comprehensive analysis of activation kinetics in thymus-initiated Cre transgenes, our data show that Cre is toxic to CD4+8+ cells in a dose-dependent fashion, and emphasize that the choice of thymus-initiated Cre strain is critically important for minimizing off-target effects of Cre. PMID:23049709

  20. A recombinase-mediated transcriptional induction system in transgenic plants

    DEFF Research Database (Denmark)

    Hoff, T; Schnorr, K M; Mundy, J

    2001-01-01

    We constructed and tested a Cre-loxP recombination-mediated vector system termed pCrox for use in transgenic plants. In this system, treatment of Arabidopsis under inducing conditions mediates an excision event that removes an intervening piece of DNA between a promoter and the gene to be expressed......-mediated GUS activation. Induction was shown to be possible at essentially any stage of plant growth. This single vector system circumvents the need for genetic crosses required by other, dual recombinase vector systems. The pCrox system may prove particularly useful in instances where transgene over...

  1. Cell-penetrating peptide-driven Cre recombination in porcine primary cells and generation of marker-free pigs.

    Science.gov (United States)

    Kang, Qianqian; Sun, Zhaolin; Zou, Zhiyuan; Wang, Ming; Li, Qiuyan; Hu, Xiaoxiang; Li, Ning

    2018-01-01

    Cell-penetrating peptides (CPPs) have been increasingly used to deliver various molecules, both in vitro and in vivo. However, there are no reports of CPPs being used in porcine fetal fibroblasts (PFFs). The increased use of transgenic pigs for basic research and biomedical applications depends on the availability of technologies for efficient genetic-modification of PFFs. Here, we report that three CPPs (CPP5, TAT, and R9) can efficiently deliver active Cre recombinase protein into PFFs via an energy-dependent endocytosis pathway. The three CPP-Cre proteins can enter PFFs and subsequently perform recombination with different efficiencies. The recombination efficacy of CPP5-Cre was found to be nearly 90%. The rate-limiting step for CPP-Cre-mediated recombination was the step of endosome escape. HA2 and chloroquine were found to improve the recombination efficiency of TAT-Cre. Furthermore, we successfully obtained marker-free transgenic pigs using TAT-Cre and CPP5-Cre. We provide a framework for the development of CPP-based farm animal transgenic technologies that would be beneficial to agriculture and biomedicine.

  2. Site-specific modification of genome with cell-permeable Cre fusion protein in preimplantation mouse embryo

    International Nuclear Information System (INIS)

    Kim, Kyoungmi; Kim, Hwain; Lee, Daekee

    2009-01-01

    Site-specific recombination (SSR) by Cre recombinase and its target sequence, loxP, is a valuable tool in genetic analysis of gene function. Recently, several studies reported successful application of Cre fusion protein containing protein transduction peptide for inducing gene modification in various mammalian cells including ES cell as well as in the whole animal. In this study, we show that a short incubation of preimplantation mouse embryos with purified cell-permeable Cre fusion protein results in efficient SSR. X-Gal staining of preimplantation embryos, heterozygous for Gtrosa26 tm1Sor , revealed that treatment of 1-cell or 2-cell embryos with 3 μM of Cre fusion protein for 2 h leads to Cre-mediated excision in 70-85% of embryos. We have examined the effect of the concentration of the Cre fusion protein and the duration of the treatment on embryonic development, established a condition for full term development and survival to adulthood, and demonstrated the germ line transmission of excised Gtrosa26 allele. Potential applications and advantages of the highly efficient technique described here are discussed.

  3. RecET driven chromosomal gene targeting to generate a RecA deficient Escherichia coli strain for Cre mediated production of minicircle DNA

    Directory of Open Access Journals (Sweden)

    Coutelle Charles

    2006-03-01

    Full Text Available Abstract Background Minicircle DNA is the non-replicating product of intramolecular site-specific recombination within a bacterial minicircle producer plasmid. Minicircle DNA can be engineered to contain predominantly human sequences which have a low content of CpG dinucleotides and thus reduced immunotoxicity for humans, whilst the immunogenic bacterial origin and antibiotic resistance marker gene sequences are entirely removed by site-specific recombination. This property makes minicircle DNA an excellent vector for non-viral gene therapy. Large-scale production of minicircle DNA requires a bacterial strain expressing tightly controlled site-specific recombinase, such as Cre recombinase. As recombinant plasmids tend to be more stable in RecA-deficient strains, we aimed to construct a recA- bacterial strain for generation of minicircle vector DNA with less chance of unwanted deletions. Results We describe here the construction of the RecA-deficient minicircle DNA producer Escherichia coli HB101Cre with a chromosomally located Cre recombinase gene under the tight control of the araC regulon. The Cre gene expression cassette was inserted into the chromosomal lacZ gene by creating transient homologous recombination proficiency in the recA- strain HB101 using plasmid-born recET genes and homology-mediated chromosomal "pop-in, pop-out" of the plasmid pBAD75Cre containing the Cre gene and a temperature sensitive replication origin. Favourably for the Cre gene placement, at the "pop-out" step, the observed frequency of RecET-led recombination between the proximal regions of homology was 10 times higher than between the distal regions. Using the minicircle producing plasmid pFIXluc containing mutant loxP66 and loxP71 sites, we isolated pure minicircle DNA from the obtained recA- producer strain HB101Cre. The minicircle DNA preparation consisted of monomeric and, unexpectedly, also multimeric minicircle DNA forms, all containing the hybrid loxP66

  4. Inducible targeting of CNS astrocytes in Aldh1l1-CreERT2 BAC transgenic mice [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Jan Winchenbach

    2016-12-01

    Full Text Available Background: Studying astrocytes in higher brain functions has been hampered by the lack of genetic tools for the efficient expression of inducible Cre recombinase throughout the CNS, including the neocortex. Methods: Therefore, we generated BAC transgenic mice, in which CreERT2 is expressed under control of the Aldh1l1 regulatory region. Results: When crossbred to Cre reporter mice, adult Aldh1l1-CreERT2 mice show efficient gene targeting in astrocytes. No such Cre-mediated recombination was detectable in CNS neurons, oligodendrocytes, and microglia. As expected, Aldh1l1-CreERT2 expression was evident in several peripheral organs, including liver and kidney. Conclusions: Taken together, Aldh1l1-CreERT2 mice are a useful tool for studying astrocytes in neurovascular coupling, brain metabolism, synaptic plasticity and other aspects of neuron-glia interactions.

  5. Generation of a KOR-Cre knockin mouse strain to study cells involved in kappa opioid signaling.

    Science.gov (United States)

    Cai, Xiaoyun; Huang, Huizhen; Kuzirian, Marissa S; Snyder, Lindsey M; Matsushita, Megumi; Lee, Michael C; Ferguson, Carolyn; Homanics, Gregg E; Barth, Alison L; Ross, Sarah E

    2016-01-01

    The kappa opioid receptor (KOR) has numerous important roles in the nervous system including the modulation of mood, reward, pain, and itch. In addition, KOR is expressed in many non-neuronal tissues. However, the specific cell types that express KOR are poorly characterized. Here, we report the development of a KOR-Cre knockin allele, which provides genetic access to cells that express KOR. In this mouse, Cre recombinase (Cre) replaces the initial coding sequence of the Opkr1 gene (encoding the kappa opioid receptor). We demonstrate that the KOR-Cre allele mediates recombination by embryonic day 14.5 (E14.5). Within the brain, KOR-Cre shows expression in numerous areas including the cerebral cortex, nucleus accumbens and striatum. In addition, this allele is expressed in epithelium and throughout many regions of the body including the heart, lung, and liver. Finally, we reveal that KOR-Cre mediates recombination of a subset of bipolar and amacrine cells in the retina. Thus, the KOR-Cre mouse line is a valuable new tool for conditional gene manipulation to enable the study of KOR. © 2015 Wiley Periodicals, Inc.

  6. Cre Fused with RVG Peptide Mediates Targeted Genome Editing in Mouse Brain Cells In Vivo.

    Science.gov (United States)

    Zou, Zhiyuan; Sun, Zhaolin; Li, Pan; Feng, Tao; Wu, Sen

    2016-12-14

    Cell penetrating peptides (CPPs) are short peptides that can pass through cell membranes. CPPs can facilitate the cellular entry of proteins, macromolecules, nanoparticles and drugs. RVG peptide (RVG hereinafter) is a 29-amino-acid CPP derived from a rabies virus glycoprotein that can cross the blood-brain barrier (BBB) and enter brain cells. However, whether RVG can be used for genome editing in the brain has not been reported. In this work, we combined RVG with Cre recombinase for bacterial expression. The purified RVG-Cre protein cut plasmids in vitro and traversed cell membranes in cultured Neuro2a cells. By tail vein-injecting RVG-Cre into Cre reporter mouse lines mTmG and Rosa26 lacZ , we demonstrated that RVG-Cre could target brain cells and achieve targeted somatic genome editing in adult mice. This direct delivery of the gene-editing enzyme protein into mouse brains with RVG is much safer than plasmid- or viral-based methods, holding promise for further applications in the treatment of various brain diseases.

  7. Simultaneous and Sequential Integration by Cre/loxP Site-Specific Recombination in Saccharomyces cerevisiae.

    Science.gov (United States)

    Choi, Ho-Jung; Kim, Yeon-Hee

    2018-05-28

    A Cre/ loxP -δ-integration system was developed to allow sequential and simultaneous integration of a multiple gene expression cassette in Saccharomyces cerevisiae . To allow repeated integrations, the reusable Candida glabrata MARKER ( CgMARKER ) carrying loxP sequences was used, and the integrated CgMARKER was efficiently removed by inducing Cre recombinase. The XYLP and XYLB genes encoding endoxylanase and β-xylosidase, respectively, were used as model genes for xylan metabolism in this system, and the copy number of these genes was increased to 15.8 and 16.9 copies/cell, respectively, by repeated integration. This integration system is a promising approach for the easy construction of yeast strains with enhanced metabolic pathways through multicopy gene expression.

  8. Molecular switch of Cre/loxP for radiation modulated gene therapy on hepatoma

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Y.-J. [Institute of Radiological Sciences, National Yang-Ming University, Taiwan (China); Chen, Fu-Du [Institute of Radiological Sciences, National Yang-Ming University, Taiwan (China); Institute of Radiological Sciences, Central Taiwan University of Science and Technology, Taiwan (China); Wang, F.H. [National Yang-Ming University Medical School, Taiwan (China); Ke, C.C. [National PET/Cyclotron Center, Taipei Veterans General Hospital, Taiwan (China); Wang, H.-E. [Institute of Radiological Sciences, National Yang-Ming University, Taiwan (China); Liu, R.-S. [Institute of Radiological Sciences, National Yang-Ming University, Taiwan (China) and National Yang-Ming University Medical School, Taiwan (China) and National PET/Cyclotron Center, Taipei Veterans General Hospital, Taiwan (China)]. E-mail: maimai5010@yahoo.com.tw

    2007-02-01

    For the purpose of enhancement of AFP promoter for the use of radiation modulated gene therapy for hepatocellular carcinoma (HCC), we combined hepatitis B virus (HBV) enhancer II with AFP promoter which shows the selectivity to the target cells to control the Cre/loxP system. Different gene constructs, pE4luc, pE4Tk, EIIAPA-Cre, E4CMV-STOP-Tk and chimeric promoters combined with HBV enhancer were constructed and transfected into HepG2, HeLa and NIH-3T3 cell lines. Cell experiments revealed that E4 enhancer responses to radiation best after 60 h irradiation at a dose range of 5-7 Gy in HepG2 stable clone. The EIIAPA promoter provided high specificity to hepatoma and activated the Cre downstream and removed the stop cassette only in hepatoma cells. After removal of the stop cassette, the E4 response to radiation could encode more Tk protein and kill more tumor cells. In summary, the chimeric EIIAPA promoter can stringently control the expression of Cre recombinase only in HCC. The radiation effect of the EIIAPA-Cre and E4CMV-STOP-Tk system shows promising results in terms of cell survival of HCC.

  9. Molecular switch of Cre/loxP for radiation modulated gene therapy on hepatoma

    International Nuclear Information System (INIS)

    Hsieh, Y.-J.; Chen, Fu-Du; Wang, F.H.; Ke, C.C.; Wang, H.-E.; Liu, R.-S.

    2007-01-01

    For the purpose of enhancement of AFP promoter for the use of radiation modulated gene therapy for hepatocellular carcinoma (HCC), we combined hepatitis B virus (HBV) enhancer II with AFP promoter which shows the selectivity to the target cells to control the Cre/loxP system. Different gene constructs, pE4luc, pE4Tk, EIIAPA-Cre, E4CMV-STOP-Tk and chimeric promoters combined with HBV enhancer were constructed and transfected into HepG2, HeLa and NIH-3T3 cell lines. Cell experiments revealed that E4 enhancer responses to radiation best after 60 h irradiation at a dose range of 5-7 Gy in HepG2 stable clone. The EIIAPA promoter provided high specificity to hepatoma and activated the Cre downstream and removed the stop cassette only in hepatoma cells. After removal of the stop cassette, the E4 response to radiation could encode more Tk protein and kill more tumor cells. In summary, the chimeric EIIAPA promoter can stringently control the expression of Cre recombinase only in HCC. The radiation effect of the EIIAPA-Cre and E4CMV-STOP-Tk system shows promising results in terms of cell survival of HCC

  10. Functionally Complete Excision of Conditional Alleles in the Mouse Suprachiasmatic Nucleus by Vgat-ires-Cre.

    Science.gov (United States)

    Weaver, David R; van der Vinne, Vincent; Giannaris, E Lela; Vajtay, Thomas J; Holloway, Kristopher L; Anaclet, Christelle

    2018-04-01

    Mice with targeted gene disruption have provided important information about the molecular mechanisms of circadian clock function. A full understanding of the roles of circadian-relevant genes requires manipulation of their expression in a tissue-specific manner, ideally including manipulation with high efficiency within the suprachiasmatic nuclei (SCN). To date, conditional manipulation of genes within the SCN has been difficult. In a previously developed mouse line, Cre recombinase was inserted into the vesicular GABA transporter (Vgat) locus. Since virtually all SCN neurons are GABAergic, this Vgat-Cre line seemed likely to have high efficiency at disrupting conditional alleles in SCN. To test this premise, the efficacy of Vgat-Cre in excising conditional (fl, for flanked by LoxP) alleles in the SCN was examined. Vgat-Cre-mediated excision of conditional alleles of Clock or Bmal1 led to loss of immunostaining for products of the targeted genes in the SCN. Vgat-Cre + ; Clock fl/fl ; Npas2 m/m mice and Vgat-Cre + ; Bmal1 fl/fl mice became arrhythmic immediately upon exposure to constant darkness, as expected based on the phenotype of mice in which these genes are disrupted throughout the body. The phenotype of mice with other combinations of Vgat-Cre + , conditional Clock, and mutant Npas2 alleles also resembled the corresponding whole-body knockout mice. These data indicate that the Vgat-Cre line is useful for Cre-mediated recombination within the SCN, making it useful for Cre-enabled technologies including gene disruption, gene replacement, and opto- and chemogenetic manipulation of the SCN circadian clock.

  11. Reappraisal of VAChT-Cre: Preference in slow motor neurons innervating type I or IIa muscle fibers.

    Science.gov (United States)

    Misawa, Hidemi; Inomata, Daijiro; Kikuchi, Miseri; Maruyama, Sae; Moriwaki, Yasuhiro; Okuda, Takashi; Nukina, Nobuyuki; Yamanaka, Tomoyuki

    2016-11-01

    VAChT-Cre.Fast and VAChT-Cre.Slow mice selectively express Cre recombinase in approximately one half of postnatal somatic motor neurons. The mouse lines have been used in various studies with selective genetic modifications in adult motor neurons. In the present study, we crossed VAChT-Cre lines with a reporter line, CAG-Syp/tdTomato, in which synaptophysin-tdTomato fusion proteins are efficiently sorted to axon terminals, making it possible to label both cell bodies and axon terminals of motor neurons. In the mice, Syp/tdTomato fluorescence preferentially co-localized with osteopontin, a recently discovered motor neuron marker for slow-twitch fatigue-resistant (S) and fast-twitch fatigue-resistant (FR) types. The fluorescence did not preferentially co-localize with matrix metalloproteinase-9, a marker for fast-twitch fatigable (FF) motor neurons. In the neuromuscular junctions, Syp/tdTomato fluorescence was detected mainly in motor nerve terminals that innervate type I or IIa muscle fibers. These results suggest that the VAChT-Cre lines are Cre-drivers that have selectivity in S and FR motor neurons. In order to avoid confusion, we have changed the mouse line names from VAChT-Cre.Fast and VAChT-Cre.Slow to VAChT-Cre.Early and VAChT-Cre.Late, respectively. The mouse lines will be useful tools to study slow-type motor neurons, in relation to physiology and pathology. © 2016 Wiley Periodicals, Inc.

  12. Generation of a tenascin-C-CreER2 knockin mouse line for conditional DNA recombination in renal medullary interstitial cells.

    Directory of Open Access Journals (Sweden)

    Wenjuan He

    Full Text Available Renal medullary interstitial cells (RMIC are specialized fibroblast-like cells that exert important functions in maintaining body fluid homeostasis and systemic blood pressure. Here, we generated a RMIC specific tenascin-C promoter driven inducible CreER2 knockin mouse line with an EGFP reporter. Similar as endogenous tenascin-C expression, the reporter EGFP expression in the tenascin-C-CreER2(+/- mice was observed in the inner medulla of the kidney, and co-localized with COX2 but not with AQP2 or AQP1, suggesting selective expression in RMICs. After recombination (tenascin-C-CreER2(+/-/ROSA26-lacZ(+/- mice + tamoxifen, β-gal activity was restricted to the cells in the inner medulla of the kidney, and didn't co-localize with AQP2, consistent with selective Cre recombinase activity in RMICs. Cre activity was not obvious in other major organs or without tamoxifen treatment. This inducible RMIC specific Cre mouse line should therefore provide a novel tool to manipulate genes of interest in RMICs.

  13. Atrial cardiomyocyte-specific expression of Cre recombinase driven by an Nppa gene fragment

    NARCIS (Netherlands)

    de Lange, Frederik J.; Moorman, Antoon F. M.; Christoffels, Vincent M.

    2003-01-01

    To study the development of the atria, we produced a transgenic mouse line that expresses Cre under the regulatory control of a 7 kbp fragment of the Natriuretic peptide precursor type A gene (Nppa), from -3 kbp to +4 kbp relative to the transcription start site. Crossing this line with the R26R and

  14. An Lck-cre transgene accelerates autoantibody production and lupus development in (NZB × NZW)F1 mice

    Science.gov (United States)

    Nelson, Richard K.; Gould, Karen A.

    2015-01-01

    Lupus is an autoimmune disease characterized by the development of antinuclear autoantibodies and immune complex-mediated tissue damage. T cells in lupus patients appear to undergo apoptosis at an increased rate, and this enhanced T cell apoptosis has been postulated to contribute to lupus pathogenesis by increasing autoantigen load. However, there is no direct evidence to support this hypothesis. In this study, we show that an Lck-cre transgene, which increases T cell apoptosis as a result of T cell specific expression of cre recombinase, accelerates the development of autoantibodies and nephritis in lupus-prone (NZB×NZW)F1 mice. Although the enhanced T cell apoptosis in Lck-cre transgenic mice resulted in an overall decrease in the relative abundance of splenic CD4+ and CD8+ T cells, the proportion of activated CD4+ T cells was increased and no significant change was observed in the relative abundance of suppressive T cells. We postulate that the Lck-cre transgene promoted lupus by enhancing T cells apoptosis, which, in conjunction with the impaired clearance of apoptotic cells in lupus-prone mice, increased the nuclear antigen load and accelerated the development of anti-nuclear autoantibodies. Furthermore, our results also underscore the importance of including cre-only controls in studies using the cre-lox system. PMID:26385218

  15. Mouse model of proximal colon-specific tumorigenesis driven by microsatellite instability-induced Cre-mediated inactivation of Apc and activation of Kras.

    Science.gov (United States)

    Kawaguchi, Yasuo; Hinoi, Takao; Saito, Yasufumi; Adachi, Tomohiro; Miguchi, Masashi; Niitsu, Hiroaki; Sasada, Tatsunari; Shimomura, Manabu; Egi, Hiroyuki; Oka, Shiro; Tanaka, Shinji; Chayama, Kazuaki; Sentani, Kazuhiro; Oue, Naohide; Yasui, Wataru; Ohdan, Hideki

    2016-05-01

    KRAS gene mutations are found in 40-50% of colorectal cancer cases, but their functional contribution is not fully understood. To address this issue, we generated genetically engineered mice with colon tumors expressing an oncogenic Kras(G12D) allele in the context of the Adenomatous polyposis coli (Apc) deficiency to compare them to tumors harboring Apc deficiency alone. CDX2P9.5-G22Cre (referred to as G22Cre) mice showing inducible Cre recombinase transgene expression in the proximal colon controlled under the CDX2 gene promoter were intercrossed with Apc (flox/flox) mice and LSL-Kras (G12D) mice carrying loxP-flanked Apc and Lox-Stop-Lox oncogenic Kras(G12D) alleles, respectively, to generate G22Cre; Apc(flox/flox); Kras(G12D) and G22Cre; Apc(flox/flox); KrasWT mice. Gene expression profiles of the tumors were analyzed using high-density oligonucleotide arrays. Morphologically, minimal difference in proximal colon tumor was observed between the two mouse models. Consistent with previous findings in vitro, Glut1 transcript and protein expression was up-regulated in the tumors of G22Cre;Apc (flox/flox) ; Kras(G12D) mice. Immunohistochemical staining analysis revealed that GLUT1 protein expression correlated with KRAS mutations in human colorectal cancer. Microarray analysis identified 11 candidate genes upregulated more than fivefold and quantitative PCR analysis confirmed that Aqp8, Ttr, Qpct, and Slc26a3 genes were upregulated 3.7- to 30.2-fold in tumors with mutant Kras. These results demonstrated the validity of the G22Cre; Apc(flox/flox) ;Kras (G12D) mice as a new mouse model with oncogenic Kras activation. We believe that this model can facilitate efforts to define novel factors that contribute to the pathogenesis of human colorectal cancer with KRAS mutations.

  16. Cre-mediated cell ablation contests mast cell contribution in models of antibody- and T cell-mediated autoimmunity.

    Science.gov (United States)

    Feyerabend, Thorsten B; Weiser, Anne; Tietz, Annette; Stassen, Michael; Harris, Nicola; Kopf, Manfred; Radermacher, Peter; Möller, Peter; Benoist, Christophe; Mathis, Diane; Fehling, Hans Jörg; Rodewald, Hans-Reimer

    2011-11-23

    Immunological functions of mast cells remain poorly understood. Studies in Kit mutant mice suggest key roles for mast cells in certain antibody- and T cell-mediated autoimmune diseases. However, Kit mutations affect multiple cell types of both immune and nonimmune origin. Here, we show that targeted insertion of Cre-recombinase into the mast cell carboxypeptidase A3 locus deleted mast cells in connective and mucosal tissues by a genotoxic Trp53-dependent mechanism. Cre-mediated mast cell eradication (Cre-Master) mice had, with the exception of a lack of mast cells and reduced basophils, a normal immune system. Cre-Master mice were refractory to IgE-mediated anaphylaxis, and this defect was rescued by mast cell reconstitution. This mast cell-deficient strain was fully susceptible to antibody-induced autoimmune arthritis and to experimental autoimmune encephalomyelitis. Differences comparing Kit mutant mast cell deficiency models to selectively mast cell-deficient mice call for a systematic re-evaluation of immunological functions of mast cells beyond allergy. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Conditional and inducible transgene expression in endothelial and hematopoietic cells using Cre/loxP and tetracycline-off systems.

    Science.gov (United States)

    Liu, Ju; Deutsch, Urban; Fung, Iris; Lobe, Corrinne G

    2014-11-01

    In the present study, the tetracycline-off and Cre/ loxP systems were combined to gain temporal and spatial control of transgene expression. Mice were generated that carried three transgenes: Tie2-tTA, tet-O-Cre and either the ZEG or ZAP reporter. Tie2-tTA directs expression of tetracycline-controlled transactivator (tTA) in endothelial and hematopoietic cells under the control of the Tie2 promoter. Tet-O-Cre produces Cre recombinase from a minimal promoter containing the tet-operator (tetO). ZEG or ZAP contains a strong promoter and a loxP -flanked stop sequence, followed by an enhanced green fluorescence protein (EGFP) or human placental alkaline phosphatase (hPLAP) reporter. In the presence of tetracycline, the tTA transactivator produced by Tie-2-tTA is disabled and Cre is not expressed. In the absence of tetracycline, the tTA binds tet-O-Cre to drive the expression of Cre, which recombines the loxP sites of the ZEG or ZAP transgene and results in reporter gene expression. In the present study, the expression of the ZEG or ZAP reporter genes in embryos and adult animals with and without tetracycline treatment was examined. In the presence of tetracycline, no reporter gene expression was observed. When tetracycline was withdrawn, Cre excision was activated and the reporter genes were detected in endothelial and hematopoietic cells. These results demonstrate that this system may be used to bypass embryonic lethality and access adult phenotypes.

  18. lck-Driven Cre Expression Alters T Cell Development in the Thymus and the Frequencies and Functions of Peripheral T Cell Subsets.

    Science.gov (United States)

    Carow, Berit; Gao, Yu; Coquet, Jonathan; Reilly, Marie; Rottenberg, Martin E

    2016-09-15

    Conditional gene targeting using the bacteriophage-derived Cre recombinase is widely applied for functional gene studies in mice. Mice transgenic for Cre under the control of the lck gene promoter are used to study the role of loxP-targeted genes in T cell development and function. In this article, we show a striking 65% reduction in cellularity, preferential development of γδ versus αβ T cells, and increased expression of IL-7R in the thymus of mice expressing Cre under the proximal lck promoter (lck-cre(+) mice). The transition from CD4/CD8 double-negative to double-positive cells was blocked, and lck-cre(+) double-positive cells were more prone to apoptosis and showed higher levels of Cre expression. Importantly, numbers of naive T cells were reduced in spleens and lymph nodes of lck-cre(+) mice. In contrast, frequencies of γδ T cells, CD44(+)CD62L(-) effector T cells, and Foxp3(+) regulatory T cells were elevated, as was the frequency of IFN-γ-secreting CD4(+) and CD8(+) T cells. A literature survey of 332 articles that used lck-cre(+) mice for deletion of floxed genes indicated that results are statistically influenced by the control used (lck-cre(+) or lck-cre(-)), more frequently resembling the lck-cre(+) phenotype described in this article if lck-cre(-) controls were used. Altogether, care should be taken when interpreting published results and to properly control targeted gene deletions using the lck-cre(+) strain. Copyright © 2016 by The American Association of Immunologists, Inc.

  19. Discovery of Novel Drugs to Improve Bone Health in Neurofibromatosis Type 1: The Wnt/Beta-Catenin Pathway in Fracture Repair and Pseudarthrosis

    Science.gov (United States)

    2015-08-01

    gene can be deleted when cells are exposed to Cre-Recombinase were studied. An adenovirus expressing Cre-Recombinase was injected to the fracture ...alleles in fracture repair infection with an adenovirus-expressing cre-recombinase (Ad-cre) is used. With this approach, data from our lab and others...previously reported and used in our work examining β-catenin in fracture healing2. The floxed alleles were activated using infection with Ad- cre before and

  20. Cold inducible promoter driven Cre-lox system proved to be highly efficient for marker gene excision in transgenic barley.

    Science.gov (United States)

    Éva, Csaba; Téglás, Flóra; Zelenyánszki, Helga; Tamás, Cecília; Juhász, Angéla; Mészáros, Klára; Tamás, László

    2018-01-10

    A Cre-lox based auto-excision strategy has been adapted for barley, capable of cre and selectable marker gene (SMG) removal. The cold inducible wheat promoter called wcs120 was utilised for driving Cre expression. The binary vector was carrying the transgene (uidA) and a so called 'recombination cassette' flanked by the lox sequences. This part included both the recombinase gene and the SMG (bar) under the control of a constitutive promoter. T 0 , T 1 and T 2 transgenic plants were subjected to low temperature (at 4°C, 10°C and 12°C) at different developmental stages to induce recombination. The presence of uidA, cre, and bar genes and recombination footprints were studied by PCR and DNA sequencing, while cre transcription was followed by qRT-PCR. These analyses indicated that, cold treatment of the germinating seeds (4°C for 3days) followed by plant growing at higher temperature (24°C) has been the most efficient (90-100%), and this treatment lead to heritable changes in the genome. Thermal separation of Cre accumulation (at low temperature) from Cre enzyme activity (at higher temperature) could have prevented the premature excision of its own encoding gene, and lead to high expression level thereby increasing recombination frequency. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. STIM1fl/fl Ksp-Cre Mouse has Impaired Renal Water Balance

    Directory of Open Access Journals (Sweden)

    Liudmila Cebotaru

    2016-06-01

    Full Text Available Background/AIM: STIM1 is as an essential component in store operated Ca2+ entry. However give the paucity of information on the role of STIM1 in kidney, the aim was to study the function of STIM1 in the medulla of the kidney. Methods: we crossed a Ksp-cre mouse with another mouse containing two loxP sites flanking Exon 6 of STIM1. The Ksp-cre mouse is based upon the Ksp-cadherin gene promoter which expresses cre recombinase in developing nephrons, collecting ducts (SD and thick ascending limbs (TAL of the loop of Henle. Results: The offspring of these mice are viable without gross morphological changes, however, we noticed that the STIM1 Ksp-cre knockout mice produced more urine compared to control. To examine this more carefully, we fed mice low (LP and high protein (HP diets respectively. When mice were fed HP diet STIM1 ko mice had significantly increased urinary volume and lower specific gravity compared to wt mice. In STIM1 ko mice fed HP diet urine creatinine and urea were significantly lower compared to wt mice fed HP diet, however the fractional excretion was the same. Conclusion: These data support the idea that STIM1 ko mice have impaired urinary concentrating ability when challenged with HP diet is most likely caused by impaired Ca2+-dependent signal transduction through the vasopressin receptor cascade.

  2. An Lck-cre transgene accelerates autoantibody production and lupus development in (NZB × NZW)F1 mice.

    Science.gov (United States)

    Nelson, R K; Gould, K A

    2016-02-01

    Lupus is an autoimmune disease characterized by the development of antinuclear autoantibodies and immune complex-mediated tissue damage. T cells in lupus patients appear to undergo apoptosis at an increased rate, and this enhanced T cell apoptosis has been postulated to contribute to lupus pathogenesis by increasing autoantigen load. However, there is no direct evidence to support this hypothesis. In this study, we show that an Lck-cre transgene, which increases T cell apoptosis as a result of T cell-specific expression of cre recombinase, accelerates the development of autoantibodies and nephritis in lupus-prone (NZB × NZW)F1 mice. Although the enhanced T cell apoptosis in Lck-cre transgenic mice resulted in an overall decrease in the relative abundance of splenic CD4(+) and CD8(+) T cells, the proportion of activated CD4(+) T cells was increased and no significant change was observed in the relative abundance of suppressive T cells. We postulate that the Lck-cre transgene promoted lupus by enhancing T cell apoptosis, which, in conjunction with the impaired clearance of apoptotic cells in lupus-prone mice, increased the nuclear antigen load and accelerated the development of anti-nuclear autoantibodies. Furthermore, our results also underscore the importance of including cre-only controls in studies using the cre-lox system. © The Author(s) 2015.

  3. Broader expression of the mouse platelet factor 4-cre transgene beyond the megakaryocyte lineage.

    Science.gov (United States)

    Pertuy, F; Aguilar, A; Strassel, C; Eckly, A; Freund, J-N; Duluc, I; Gachet, C; Lanza, F; Léon, C

    2015-01-01

    Transgenic mice expressing cre recombinase under the control of the platelet factor 4 (Pf4) promoter, in the context of a 100-kb bacterial artificial chromosome, have become a valuable tool with which to study genetic modifications in the platelet lineage. However, the specificity of cre expression has recently been questioned, and the time of its onset during megakaryopoiesis remains unknown. To characterize the expression of this transgene, we used double-fluorescent cre reporter mice. In the bone marrow, Pf4-cre-mediated recombination had occurred in all CD42-positive megakaryocytes as early as stage I of maturation, and in rare CD42-negative cells. In circulating blood, all platelets had recombined, along with only a minor fraction of CD45-positive cells. However, we found that all tissues contained recombined cells of monocyte/macrophage origin. When recombined, these cells might potentially modify the function of the tissues under particular conditions, especially inflammatory conditions, which further increase recombination in immune cells. Unexpectedly, a subset of epithelial cells from the distal colon showed signs of recombination resulting from endogenous Pf4-cre expression. This is probably the basis of the unexplained colon tumors developed by Apc(flox/flox) ;Pf4-cre mice, generated in a separate study on the role of Apc in platelet formation. Altogether, our results indicate early recombination with full penetrance in megakaryopoiesis, and confirm the value of Pf4-cre mice for the genetic engineering of megakaryocytes and platelets. However, care must be taken when investigating the role of platelets in processes outside hemostasis, especially when immune cells might be involved. © 2014 International Society on Thrombosis and Haemostasis.

  4. Sexually dimorphic distribution of Prokr2 neurons revealed by the Prokr2-Cre mouse model.

    Science.gov (United States)

    Mohsen, Zaid; Sim, Hosung; Garcia-Galiano, David; Han, Xingfa; Bellefontaine, Nicole; Saunders, Thomas L; Elias, Carol F

    2017-12-01

    Prokineticin receptor 2 (PROKR2) is predominantly expressed in the mammalian central nervous system. Loss-of-function mutations of PROKR2 in humans are associated with Kallmann syndrome due to the disruption of gonadotropin releasing hormone neuronal migration and deficient olfactory bulb morphogenesis. PROKR2 has been also implicated in the neuroendocrine control of GnRH neurons post-migration and other physiological systems. However, the brain circuitry and mechanisms associated with these actions have been difficult to investigate mainly due to the widespread distribution of Prokr2-expressing cells, and the lack of animal models and molecular tools. Here, we describe the generation, validation and characterization of a new mouse model that expresses Cre recombinase driven by the Prokr2 promoter, using CRISPR-Cas9 technology. Cre expression was visualized using reporter genes, tdTomato and GFP, in males and females. Expression of Cre-induced reporter genes was found in brain sites previously described to express Prokr2, e.g., the paraventricular and the suprachiasmatic nuclei, and the area postrema. The Prokr2-Cre mouse model was further validated by colocalization of Cre-induced GFP and Prokr2 mRNA. No disruption of Prokr2 expression, GnRH neuronal migration or fertility was observed. Comparative analysis of Prokr2-Cre expression in male and female brains revealed a sexually dimorphic distribution confirmed by in situ hybridization. In females, higher Cre activity was found in the medial preoptic area, ventromedial nucleus of the hypothalamus, arcuate nucleus, medial amygdala and lateral parabrachial nucleus. In males, Cre was higher in the amygdalo-hippocampal area. The sexually dimorphic pattern of Prokr2 expression indicates differential roles in reproductive function and, potentially, in other physiological systems.

  5. A next-generation dual-recombinase system for time and host specific targeting of pancreatic cancer

    Science.gov (United States)

    Schachtler, Christina; Zukowska, Magdalena; Eser, Stefan; Feyerabend, Thorsten B.; Paul, Mariel C.; Eser, Philipp; Klein, Sabine; Lowy, Andrew M.; Banerjee, Ruby; Yang, Fangtang; Lee, Chang-Lung; Moding, Everett J.; Kirsch, David G.; Scheideler, Angelika; Alessi, Dario R.; Varela, Ignacio; Bradley, Allan; Kind, Alexander; Schnieke, Angelika E.; Rodewald, Hans-Reimer; Rad, Roland; Schmid, Roland M.; Schneider, Günter; Saur, Dieter

    2014-01-01

    Genetically engineered mouse models (GEMMs) have dramatically improved our understanding of tumor evolution and therapeutic resistance. However, sequential genetic manipulation of gene expression and targeting of the host is almost impossible using conventional Cre-loxP–based models. We have developed an inducible dual-recombinase system by combining flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies to improve GEMMs of pancreatic cancer. This enables investigation of multistep carcinogenesis, genetic manipulation of tumor subpopulations (such as cancer stem cells), selective targeting of the tumor microenvironment and genetic validation of therapeutic targets in autochthonous tumors on a genome-wide scale. As a proof of concept, we performed tumor cell–autonomous and nonautonomous targeting, recapitulated hallmarks of human multistep carcinogenesis, validated genetic therapy by 3-phosphoinositide-dependent protein kinase inactivation as well as cancer cell depletion and show that mast cells in the tumor microenvironment, which had been thought to be key oncogenic players, are dispensable for tumor formation. PMID:25326799

  6. A next-generation dual-recombinase system for time- and host-specific targeting of pancreatic cancer.

    Science.gov (United States)

    Schönhuber, Nina; Seidler, Barbara; Schuck, Kathleen; Veltkamp, Christian; Schachtler, Christina; Zukowska, Magdalena; Eser, Stefan; Feyerabend, Thorsten B; Paul, Mariel C; Eser, Philipp; Klein, Sabine; Lowy, Andrew M; Banerjee, Ruby; Yang, Fangtang; Lee, Chang-Lung; Moding, Everett J; Kirsch, David G; Scheideler, Angelika; Alessi, Dario R; Varela, Ignacio; Bradley, Allan; Kind, Alexander; Schnieke, Angelika E; Rodewald, Hans-Reimer; Rad, Roland; Schmid, Roland M; Schneider, Günter; Saur, Dieter

    2014-11-01

    Genetically engineered mouse models (GEMMs) have dramatically improved our understanding of tumor evolution and therapeutic resistance. However, sequential genetic manipulation of gene expression and targeting of the host is almost impossible using conventional Cre-loxP-based models. We have developed an inducible dual-recombinase system by combining flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies to improve GEMMs of pancreatic cancer. This enables investigation of multistep carcinogenesis, genetic manipulation of tumor subpopulations (such as cancer stem cells), selective targeting of the tumor microenvironment and genetic validation of therapeutic targets in autochthonous tumors on a genome-wide scale. As a proof of concept, we performed tumor cell-autonomous and nonautonomous targeting, recapitulated hallmarks of human multistep carcinogenesis, validated genetic therapy by 3-phosphoinositide-dependent protein kinase inactivation as well as cancer cell depletion and show that mast cells in the tumor microenvironment, which had been thought to be key oncogenic players, are dispensable for tumor formation.

  7. A Trp53fl/flPtenfl/fl mouse model of undifferentiated pleomorphic sarcoma mediated by adeno-Cre injection and in vivo bioluminescence imaging.

    Directory of Open Access Journals (Sweden)

    Marisa R Buchakjian

    Full Text Available Genetic mouse models of soft tissue sarcoma provide critical insights into disease pathophysiology, which are oftentimes unable to be extracted from human tumor samples or xenograft models. In this study we describe a mouse model of soft tissue sarcoma mediated by adenoviral-Cre recombinase injection into Trp53fl/fl/Ptenfl/fl lox-stop-lox luciferase mice. Injection of adenovirus expressing Cre recombinase, either subcutaneously or intramuscularly in two experimental groups, results in viral infection and gene recombination with 100% penetrance within the first 24 hours following injection. Luciferase expression measured by real-time bioluminescence imaging increases over time, with an initial robust increase following viral injection, followed by a steady rise over the next several weeks as primary tumors develop and grow. Intramuscular injections were more commonly associated with evidence of systemic viral distribution than subcutaneous injections. All mice developed soft tissue sarcomas at the primary injection site, with histological examination identifying 93% of tumors as invasive pleomorphic sarcomas based on microscopic morphology and immunohistochemical expression of sarcoma markers. A lymphocytic infiltrate was present in 64% of the sarcomas in this immunocompetent model and 71% of tumors expressed PD-L1. This is the first report of a viral-Cre mediated Trp53/Pten mouse model of undifferentiated pleomorphic sarcoma. The bioluminescence imaging feature, along with high penetrance of the model and its immunological characteristics, makes it suited for pre-clinical studies of soft tissue sarcoma.

  8. Discovery of Nigri/nox and Panto/pox site-specific recombinase systems facilitates advanced genome engineering.

    Science.gov (United States)

    Karimova, Madina; Splith, Victoria; Karpinski, Janet; Pisabarro, M Teresa; Buchholz, Frank

    2016-07-22

    Precise genome engineering is instrumental for biomedical research and holds great promise for future therapeutic applications. Site-specific recombinases (SSRs) are valuable tools for genome engineering due to their exceptional ability to mediate precise excision, integration and inversion of genomic DNA in living systems. The ever-increasing complexity of genome manipulations and the desire to understand the DNA-binding specificity of these enzymes are driving efforts to identify novel SSR systems with unique properties. Here, we describe two novel tyrosine site-specific recombination systems designated Nigri/nox and Panto/pox. Nigri originates from Vibrio nigripulchritudo (plasmid VIBNI_pA) and recombines its target site nox with high efficiency and high target-site selectivity, without recombining target sites of the well established SSRs Cre, Dre, Vika and VCre. Panto, derived from Pantoea sp. aB, is less specific and in addition to its native target site, pox also recombines the target site for Dre recombinase, called rox. This relaxed specificity allowed the identification of residues that are involved in target site selectivity, thereby advancing our understanding of how SSRs recognize their respective DNA targets.

  9. Establishment of a Cre recombinase based mutagenesis protocol for markerless gene deletion in Streptococcus suis.

    Science.gov (United States)

    Koczula, A; Willenborg, J; Bertram, R; Takamatsu, D; Valentin-Weigand, P; Goethe, R

    2014-12-01

    The lack of knowledge about pathogenicity mechanisms of Streptococcus (S.) suis is, at least partially, attributed to limited methods for its genetic manipulation. Here, we established a Cre-lox based recombination system for markerless gene deletions in S. suis serotype 2 with high selective pressure and without undesired side effects. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. The Dmp1-SOST Transgene Interacts With and Downregulates the Dmp1-Cre Transgene and the Rosa(Notch) Allele.

    Science.gov (United States)

    Zanotti, Stefano; Canalis, Ernesto

    2016-05-01

    Activation of Notch1 in osteocytes of Rosa(Notch) mice, where a loxP-flanked STOP cassette and the Nicd coding sequence were targeted to the reverse orientation splice acceptor (Rosa)26 locus, causes osteopetrosis associated with suppressed Sost expression and enhanced Wnt signaling. To determine whether Sost downregulation mediates the effects of Notch activation in osteocytes, Rosa(Notch) mice were crossed with transgenics expressing Cre recombinase or SOST under the control of the dentin matrix protein (Dmp)1 promoter. Dmp1-SOST transgenics displayed vertebral osteopenia and a modest femoral cancellous and cortical bone phenotype, whereas hemizygous Dmp1-Cre transgenics heterozygous for the Rosa(Notch) allele (Dmp1-Cre;Rosa(Notch)) exhibited osteopetrosis. The phenotype of Notch activation in osteocytes was prevented in Dmp1-Cre;Rosa(Notch) mice hemizygous for the Dmp1-SOST transgene. The effect was associated with downregulated Notch signaling and suppressed Dmp1 and Rosa26 expression. To test whether SOST regulates Notch expression in osteocytes, cortical bone cultures from Dmp1-Cre;Rosa(Notch) mice or from Rosa(Notch) control littermates were exposed to recombinant human SOST. The addition of SOST had only modest effects on Notch target gene mRNA levels and suppressed Dmp1, but not Cre or Rosa26, expression. These findings suggest that prevention of the Dmp1-Cre;Rosa(Notch) skeletal phenotype by Dmp1-SOST is not secondary to SOST expression but to interactions among the Dmp1-SOST and Dmp1-Cre transgenes and the Rosa26 locus. In conclusion, the Dmp1-SOST transgene suppresses the expression of the Dmp1-Cre transgene and of Rosa26. © 2015 Wiley Periodicals, Inc.

  11. Altered Baseline and Nicotine-Mediated Behavioral and Cholinergic Profiles in ChAT-Cre Mouse Lines.

    Science.gov (United States)

    Chen, Edison; Lallai, Valeria; Sherafat, Yasmine; Grimes, Nickolas P; Pushkin, Anna N; Fowler, J P; Fowler, Christie D

    2018-02-28

    The recent development of transgenic rodent lines expressing cre recombinase in a cell-specific manner, along with advances in engineered viral vectors, has permitted in-depth investigations into circuit function. However, emerging evidence has begun to suggest that genetic modifications may introduce unexpected caveats. In the current studies, we sought to extensively characterize male and female mice from both the ChAT (BAC) -Cre mouse line, created with the bacterial artificial chromosome (BAC) method, and ChAT (IRES) -Cre mouse line, generated with the internal ribosome entry site (IRES) method. ChAT (BAC) -Cre transgenic and wild-type mice did not differ in general locomotor behavior, anxiety measures, drug-induced cataplexy, nicotine-mediated hypolocomotion, or operant food training. However, ChAT (BAC) -Cre transgenic mice did exhibit significant deficits in intravenous nicotine self-administration, which paralleled an increase in vesicular acetylcholine transporter and choline acetyltransferase (ChAT) hippocampal expression. For the ChAT (IRES) -Cre line, transgenic mice exhibited deficits in baseline locomotor, nicotine-mediated hypolocomotion, and operant food training compared with wild-type and hemizygous littermates. No differences among ChAT (IRES) -Cre wild-type, hemizygous, and transgenic littermates were found in anxiety measures, drug-induced cataplexy, and nicotine self-administration. Given that increased cre expression was present in the ChAT (IRES) -Cre transgenic mice, as well as a decrease in ChAT expression in the hippocampus, altered neuronal function may underlie behavioral phenotypes. In contrast, ChAT (IRES) -Cre hemizygous mice were more similar to wild-type mice in both protein expression and the majority of behavioral assessments. As such, interpretation of data derived from ChAT-Cre rodents must consider potential limitations dependent on the line and/or genotype used in research investigations. SIGNIFICANCE STATEMENT Altered

  12. Mammary Specific Expression of Cre Recombinase Under the Control of an Endogenous MMTV LTR: A Conditional Knock-Out System

    National Research Council Canada - National Science Library

    Czarneski, Jennifer

    2000-01-01

    .... Mice that carried the Mtv-17 Cre fusion vector would then be mated to mice that had the p53 locus flanked by loxP sites, resulting in the tissue-specific loss of p53 in the mammary gland only. The prediction is that these animals would only develop mammary and not other tumors. We believed that the cre-transgenic mice would also prove useful for other investigators in the mammary gland development and tumorigenesis field.

  13. R/L, a double reporter mouse line that expresses luciferase gene upon Cre-mediated excision, followed by inactivation of mRFP expression.

    Science.gov (United States)

    Jia, Junshuang; Lin, Xiaolin; Lin, Xia; Lin, Taoyan; Chen, Bangzhu; Hao, Weichao; Cheng, Yushuang; Liu, Yu; Dian, Meijuan; Yao, Kaitai; Xiao, Dong; Gu, Weiwang

    2016-10-01

    The Cre/loxP system has become an important tool for the conditional gene knockout and conditional gene expression in genetically engineered mice. The applications of this system depend on transgenic reporter mouse lines that provide Cre recombinase activity with a defined cell type-, tissue-, or developmental stage-specificity. To develop a sensitive assay for monitoring Cre-mediated DNA excisions in mice, we generated Cre-mediated excision reporter mice, designated R/L mice (R/L: mRFP(monomeric red fluorescent protein)/luciferase), express mRFP throughout embryonic development and adult stages, while Cre-mediated excision deletes a loxP-flanked mRFP reporter gene and STOP sequence, thereby activating the expression of the second reporter gene luciferase, as assayed by in vivo and ex vivo bioluminescence imaging. After germ line deletion of the floxed mRFP and STOP sequence in R/L mice by EIIa-Cre mice, the resulting luciferase transgenic mice in which the loxP-mRFP-STOP-loxP cassette is excised from all cells express luciferase in all tissues and organs examined. The expression of luciferase transgene was activated in liver of RL/Alb-Cre double transgenic mice and in brain of RL/Nestin-Cre double transgenic mice when R/L reporter mice were mated with Alb-Cre mice and Nestin-Cre mice, respectively. Our findings reveal that the double reporter R/L mouse line is able to indicate the occurrence of Cre-mediated excision from early embryonic to adult lineages. Taken together, these findings demonstrate that the R/L mice serve as a sensitive reporter for Cre-mediated DNA excision both in living animals and in organs, tissues, and cells following necropsy.

  14. Improved gene amplification by cell-cycle engineering combined with the Cre-loxP system in Chinese hamster ovary cells.

    Science.gov (United States)

    Matsuyama, Rima; Tsutsui, Tomomi; Lee, Kyoung Ho; Onitsuka, Masayoshi; Omasa, Takeshi

    2015-12-01

    The dihydrofolate reductase gene amplification system is widely used in Chinese hamster ovary (CHO) cells for the industrial production of therapeutic proteins. To enhance the efficiency of conventional gene amplification systems, we previously presented a novel method using cell-cycle checkpoint engineering. Here, we constructed high-producing and stable cells by the conditional expression of mutant cell division cycle 25 homolog B (CDC25B) using the Cre-loxP system. A bispecific antibody-producing CHO DG44-derived cell line was transfected with floxed mutant CDC25B. After inducing gene amplification in the presence of 250 nM methotrexate, mutant CDC25B sequence was removed by Cre recombinase protein expression. Overexpression of the floxed mutant CDC25B significantly enhanced the efficiency of transgene amplification and productivity. Moreover, the specific production rate of the isolated clone CHO Cre-1 and Cre-2 were approximately 11-fold and 15-fold higher than that of mock-transfected clone CHO Mock-S. Chromosomal aneuploidy was increased by mutant CDC25B overexpression, but Cre-1 and Cre-2 did not show any changes in chromosome number during long-term cultivation, as is the case with CHO Mock-S. Our results suggest that high-producing and stable cells can be constructed by conditionally controlling a cell-cycle checkpoint integrated in conventional gene amplification systems. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. Nucleic acid constructs containing orthogonal site selective recombinases (OSSRs)

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Joshua M.; Anderson, J. Christopher; Dueber, John E.

    2017-08-29

    The present invention provides for a recombinant nucleic acid comprising a nucleotide sequence comprising a plurality of constructs, wherein each construct independently comprises a nucleotide sequence of interest flanked by a pair of recombinase recognition sequences. Each pair of recombinase recognition sequences is recognized by a distinct recombinase. Optionally, each construct can, independently, further comprise one or more genes encoding a recombinase capable of recognizing the pair of recombinase recognition sequences of the construct. The recombinase can be an orthogonal (non-cross reacting), site-selective recombinase (OSSR).

  16. Nestin-Cre Mice Are Affected by Hypopituitarism, Which Is Not Due to Significant Activity of the Transgene in the Pituitary Gland

    Science.gov (United States)

    Galichet, Christophe; Lovell-Badge, Robin; Rizzoti, Karine

    2010-01-01

    Nestin-Cre mice express Cre recombinase under control of the rat nestin promoter and central nervous system (CNS) enhancer. While endogenous Nestin is expressed in some other tissues including the pituitary gland, Nestin-Cre mice induce recombination predominantly in the CNS. For this reason, they have been widely used to explore gene function or cell fate in the latter. Pituitary hormonal deficiencies, or hypopituitarism, are associated with a wide range of symptoms and with a significant morbidity. These can have a neural and/or a pituitary origin as the gland's secretions are controlled by the hypothalamus. We report here that Nestin-Cre mice themselves are affected by mild hypopituitarism. Hence, physiological consequences are expected, especially in combination with defects resulting from Cre mediated deletion of any gene under investigation. To further investigate the origin of this phenotype, we re-examined the activity of the transgene. We compared it with expression of Nestin itself in the context of the hypothalamo-pituitary axis, especially in the light of a recent report showing pituitary Nestin-Cre activity, which contrasts with previous data. Our results disagree with those of this recent study and do not support the claim that Nestin positive cells are present in the pituitary anlagen, the Rathke's pouch (RP). Moreover we did not observe any significant activity in the post-natal pituitary, in agreement with the initial report. PMID:20625432

  17. Generation of Oxtr cDNA(HA)-Ires-Cre Mice for Gene Expression in an Oxytocin Receptor Specific Manner.

    Science.gov (United States)

    Hidema, Shizu; Fukuda, Tomokazu; Hiraoka, Yuichi; Mizukami, Hiroaki; Hayashi, Ryotaro; Otsuka, Ayano; Suzuki, Shingo; Miyazaki, Shinji; Nishimori, Katsuhiko

    2016-05-01

    The neurohypophysial hormone oxytocin (OXT) and its receptor (OXTR) have critical roles in the regulation of pro-social behaviors, including social recognition, pair bonding, parental behavior, and stress-related responses. Supporting this hypothesis, a portion of patients suffering from autism spectrum disorder have mutations, such as single nucleotide polymorphisms, or epigenetic modifications in their OXTR gene. We previously reported that OXTR-deficient mice exhibit pervasive social deficits, indicating the critical role of OXTR in social behaviors. In the present study, we generated Oxtr cDNA(HA)-Ires-Cre knock-in mice, expressing both OXTR and Cre recombinase under the control of the endogenous Oxtr promoter. Knock-in cassette of Oxtr cDNA(HA)-Ires-Cre consisted of Oxtr cDNA tagged with the hemagglutinin epitope at the 3' end (Oxtr cDNA(HA)), internal ribosomal entry site (Ires), and Cre. Cre was expressed in the uterus, mammary gland, kidney, and brain of Oxtr cDNA(HA)-Ires-Cre knock-in mice. Furthermore, the distribution of Cre in the brain was similar to that observed in Oxtr-Venus fluorescent protein expressing mice (Oxtr-Venus), another animal model previously generated by our group. Social behavior of Oxtr cDNA(HA)-Ires-Cre knock-in mice was similar to that of wild-type animals. We demonstrated that this construct is expressed in OXTR-expressing neurons specifically after an infection with the recombinant adeno-associated virus carrying the flip-excision switch vector. Using this system, we showed the transport of the wheat-germ agglutinin tracing molecule from the OXTR-expressing neurons to the innervated neurons in knock-in mice. This study might contribute to the monosynaptic analysis of neuronal circuits and to the optogenetic analysis of neurons expressing OXTR. © 2015 Wiley Periodicals, Inc.

  18. Construction of permanently inducible miRNA-based expression vectors using site-specific recombinases

    Directory of Open Access Journals (Sweden)

    Garwick-Coppens Sara E

    2011-11-01

    Full Text Available Abstract Background RNA interference (RNAi is a conserved gene silencing mechanism mediated by small inhibitory microRNAs (miRNAs. Promoter-driven miRNA expression vectors have emerged as important tools for delivering natural or artificially designed miRNAs to eukaryotic cells and organisms. Such systems can be used to query the normal or pathogenic functions of natural miRNAs or messenger RNAs, or to therapeutically silence disease genes. Results As with any molecular cloning procedure, building miRNA-based expression constructs requires a time investment and some molecular biology skills. To improve efficiency and accelerate the construction process, we developed a method to rapidly generate miRNA expression vectors using recombinases instead of more traditional cut-and-paste molecular cloning techniques. In addition to streamlining the construction process, our cloning strategy provides vectors with added versatility. In our system, miRNAs can be constitutively expressed from the U6 promoter, or inducibly expressed by Cre recombinase. We also engineered a built-in mechanism to destroy the vector with Flp recombinase, if desired. Finally, to further simplify the construction process, we developed a software package that automates the prediction and design of optimal miRNA sequences using our system. Conclusions We designed and tested a modular system to rapidly clone miRNA expression cassettes. Our strategy reduces the hands-on time required to successfully generate effective constructs, and can be implemented in labs with minimal molecular cloning expertise. This versatile system provides options that permit constitutive or inducible miRNA expression, depending upon the needs of the end user. As such, it has utility for basic or translational applications.

  19. Bypass of lethality with mosaic mice generated by Cre-loxP-mediated recombination.

    Science.gov (United States)

    Betz, U A; Vosshenrich, C A; Rajewsky, K; Müller, W

    1996-10-01

    The analysis of gene function based on the generation of mutant mice by homologous recombination in embryonic stem cells is limited if gene disruption results in embryonic lethality. Mosaic mice, which contain a certain proportion of mutant cells in all organs, allow lethality to be circumvented and the potential of mutant cells to contribute to different cell lineages to be analyzed. To generate mosaic animals, we used the bacteriophage P1-derived Cre-loxP recombination system, which allows gene alteration by Cre-mediated deletion of loxP-flanked gene segments. We generated nestin-cre transgenic mouse lines, which expressed the Cre recombinase under the control of the rat nestin promoter and its second intron enhancer. In crosses to animals carrying a loxP-flanked target gene, partial deletion of the loxP-flanked allele occurred before day 10.5 post coitum and was detectable in all adult organs examined, including germ-line cells. Using this approach, we generated mosaic mice containing cells deficient in the gamma-chain of the interleukin-2 receptor (IL-2R gamma); in these animals, the IL-2R gamma-deficient cells were underrepresented in the thymus and spleen. Because mice deficient in DNA polymerase beta die perinatally, we studied the effects of DNA polymerase beta deficiency in mosaic animals. We found that some of the mosaic polymerase beta-deficient animals were viable, but were often reduced in size and weight. The fraction of DNA polymerase beta-deficient cells in mosaic embryos decreased during embryonic development, presumably because wild-type cells had a competitive advantage. The nestin-cre transgenic mice can be used to generate mosaic animals in which target genes are mutated by Cre-mediated recombination of loxP-flanked target genes. By using mosaic animals, embryonic lethality can be bypassed and cell lineages for whose development a given target gene is critical can be identified. In the case of DNA polymerase beta, deficient cells are already

  20. Self-excising Cre/mutant lox marker recycling system for multiple gene integrations and consecutive gene deletions in Aspergillus oryzae.

    Science.gov (United States)

    Zhang, Silai; Ban, Akihiko; Ebara, Naoki; Mizutani, Osamu; Tanaka, Mizuki; Shintani, Takahiro; Gomi, Katsuya

    2017-04-01

    In this study, we developed a self-excising Cre/loxP-mediated marker recycling system with mutated lox sequences to introduce a number of biosynthetic genes into Aspergillus oryzae. To construct the self-excising marker cassette, both the selectable marker, the Aspergillus nidulans adeA gene, and the Cre recombinase gene (cre), conditionally expressed by the xylanase-encoding gene promoter, were designed to be located between the mutant lox sequences, lox66 and lox71. However, construction of the plasmid failed, possibly owing to a slight expression of cre downstream of the fungal gene promoter in Escherichia coli. Hence, to avoid the excision of the cassette in E. coli, a 71-bp intron of the A. oryzae xynG2 gene was inserted into the cre gene. The A. oryzae adeA deletion mutant was transformed with the resulting plasmid in the presence of glucose, and the transformants were cultured in medium containing xylose as the sole carbon source. PCR analysis of genomic DNA from resultant colonies revealed the excision of both the marker and Cre expression construct, indicating that the self-excising marker cassette was efficient at removing the selectable marker. Using the marker recycling system, hyperproduction of kojic acid could be achieved in A. oryzae by the introduction of two genes that encode oxidoreductase and transporter. Furthermore, we also constructed an alternative marker recycling cassette bearing the A. nidulans pyrithiamine resistant gene (ptrA) as a dominant selectable marker. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. Double transduction of a Cre/LoxP lentiviral vector: a simple method to generate kidney cell-specific knockdown mice.

    Science.gov (United States)

    Nam, Bo Young; Kim, Dong Ki; Park, Jung Tak; Kang, Hye-Young; Paeng, Jisun; Kim, Seonghun; Park, Jimin; Um, Jae Eun; Oh, Hyung Jung; Han, Seung Hyeok; Yoo, Tae-Hyun; Kang, Shin-Wook

    2015-12-15

    In a lentivirus-based gene delivery system, the incorporated gene is continuously expressed for a long time. In this study, we devised a simple way to knock down a specific gene in a kidney cell-specific pattern in adult mice by lentivirus-assisted transfer of short hairpin RNA (shRNA). Kidney collecting duct (CD)-specific aquaporin-3 (AQP3)-knockdown mice were generated by consecutive injection of Hoxb7-Cre-expressing lentivirus (LV-Hoxb7 Cre) and loxP-AQP3 shRNA-expressing lentivirus (LV-loxP shAQP3) in adult C57BL6/J mice. LV-Hoxb7 Cre was designed to express mCherry, while LV-loxP shAQP3 was designed with a floxed enhanced green fluorescent protein (EGFP)-tagged stop sequence, and thus EGFP would be expressed only in the absence of Cre recombination. In mice treated with LV-Hoxb7 Cre alone, mCherry protein expression, which indicates the presence of Cre recombinase, occurred only in CD cells. However, LV-loxP shAQP3 injection alone resulted in an increase in EGFP expression in all kidney cells, indicating the transcription of the floxed region. When LV-Hoxb7 Cre and LV-loxP shAQP3 were sequentially transduced, EGFP expression was attenuated while mCherry expression was sustained in CD cells, demonstrating a CD cell-specific recombination of the floxed region. AQP3 expression in mice injected with LV-Hoxb7 Cre or LV-loxP shAQP3 alone did not differ, but consecutive injection of LV-Hoxb7 Cre and LV-loxP shAQP3 significantly reduced AQP3 expression in CD cells. However, the expression levels of AQP3 were not altered in other cell types. Double transduction of Cre- and loxP-based lentivirus can easily generate kidney cell-specific knockdown mice, and this method might be applicable to other species. Copyright © 2015 the American Physiological Society.

  2. A self-excising Cre recombinase allows efficient recombination of multiple ectopic heterospecific lox sites in transgenic tobacco

    NARCIS (Netherlands)

    Mlynarova, L.; Nap, J.P.H.

    2003-01-01

    To study the impact of different DNA configurations on the stability of transgene expression, a variant of the cre gene was developed. This variant allows for the highly efficient in planta removal of its own loxP-flanked coding sequence as well as other DNAs flanked by ectopic heterospecific lox

  3. Recombinase-mediated reprogramming and dystrophin gene addition in mdx mouse induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Chunli Zhao

    Full Text Available A cell therapy strategy utilizing genetically-corrected induced pluripotent stem cells (iPSC may be an attractive approach for genetic disorders such as muscular dystrophies. Methods for genetic engineering of iPSC that emphasize precision and minimize random integration would be beneficial. We demonstrate here an approach in the mdx mouse model of Duchenne muscular dystrophy that focuses on the use of site-specific recombinases to achieve genetic engineering. We employed non-viral, plasmid-mediated methods to reprogram mdx fibroblasts, using phiC31 integrase to insert a single copy of the reprogramming genes at a safe location in the genome. We next used Bxb1 integrase to add the therapeutic full-length dystrophin cDNA to the iPSC in a site-specific manner. Unwanted DNA sequences, including the reprogramming genes, were then precisely deleted with Cre resolvase. Pluripotency of the iPSC was analyzed before and after gene addition, and ability of the genetically corrected iPSC to differentiate into myogenic precursors was evaluated by morphology, immunohistochemistry, qRT-PCR, FACS analysis, and intramuscular engraftment. These data demonstrate a non-viral, reprogramming-plus-gene addition genetic engineering strategy utilizing site-specific recombinases that can be applied easily to mouse cells. This work introduces a significant level of precision in the genetic engineering of iPSC that can be built upon in future studies.

  4. Cre/loxP-mediated adenovirus type 5 packaging signal excision demonstrates that core element VI is sufficient for virus packaging

    International Nuclear Information System (INIS)

    Maeda, Yasushi; Kimura, En; Uchida, Yuji; Nishida, Yasuto; Yamashita, Satoshi; Arima, Toshiyuki; Uchino, Makoto

    2003-01-01

    Previous analyses have demonstrated that packaging of the adenovirus type 5 (Ad5) genome is dependent on at least seven cis-acting elements, called AI to AVII, which are located in the left-end region of the genome. These elements have different packaging efficiencies, and without AI through AV, viral DNA cannot be packaged. Here we report the identification of the cis-acting Ad5 packaging domain in vivo by using the Cre/loxP system. We found that an adenoviral DNA fragment (nt 192 to nt 358), which includes elements AI to AV, is excised by Cre recombinase and packaged into capsids. Furthermore, this mutant adenovirus replicated so efficiently by repetitive propagation that its purification by CsCI equilibrium gradient was possible. This study clarified that the region from nt 358 to nt 454 on the viral genome is sufficient for packaging. Recently, the helper-dependent adenoviral vector (HDAd) construction system has been developed for the purpose of gene therapy. This system uses a helper virus with two parallel loxP sites flanking the packaging signal. This region is eliminated by Cre-mediated excision, which prevents helper virus packaging. Our data provide useful information regarding factors affecting efficient elimination

  5. Adenovirus-mediated truncated Bid overexpression induced by the Cre/LoxP system promotes the cell apoptosis of CD133+ ovarian cancer stem cells.

    Science.gov (United States)

    Long, Qifang; Yang, Ru; Lu, Weixian; Zhu, Weipei; Zhou, Jundong; Zheng, Cui; Zhou, Dongmei; Yu, Ling; Wu, Jinchang

    2017-01-01

    Cancer stem cells are a small subset of cancer cells that contribute to cancer progression, metastasis, chemoresistance and recurrence. CD133-positive (CD133+) ovarian cancer cells have been identified as ovarian cancer stem cells. Adenovirus-mediated gene therapy is an innovative therapeutic method for cancer treatment. In the present study, we aimed to develop a new gene therapy to specifically eliminate CD133+ ovarian cancer stem cells by targeting CD133. We used the Cre/LoxP system to augment the selective expression of the truncated Bid (tBid) gene as suicide gene therapy in CD133+ ovarian cancer stem cells. The adenovirus (Ad)-CD133-Cre expressing Cre recombinase under the control of the CD133 promoter and Ad-CMV-LoxP-Neo-LoxP-tBid expressing tBid under the control of the CMV promoter were successfully constructed using the Cre/LoxP switching system. The co-infection of Ad-CMV-LoxP-Neo-LoxP-tBid and Ad-CD133-Cre selectively induced tBid overexpression, which inhibited cell growth and triggered the cell apoptosis of CD133+ ovarian cancer stem cells. The Cre/LoxP system-mediated tBid overexpression activated the pro-apoptotic signaling pathway and augmented the cytotoxic effect of cisplatin in CD133+ ovarian cancer stem cells. Furthermore, in xenograft experiments, co-infection with the two recombinant adenoviruses markedly suppressed tumor growth in vivo and promoted cell apoptosis in tumor tissues. Taken together, the present study provides evidence that the adenovirus-mediated tBid overexpression induced by the Cre/LoxP system can effectively eliminate CD133+ ovarian cancer stem cells, representing a novel therapeutic strategy for the treatment of ovarian cancer.

  6. An easy method for preparation of Cre-loxP regulated fluorescent adenoviral expression vectors and its application for direct reprogramming into hepatocytes

    Directory of Open Access Journals (Sweden)

    Chitose Kurihara

    2016-12-01

    Full Text Available The recombinant adenoviral gene expression system is a powerful tool for gene delivery. However, it is difficult to obtain high titers of infectious virus, principally due to the toxicity of the expressed gene which affects on virus replication in the host HEK293 cells. To avoid these problems, we generated a Cre-loxP-regulated fluorescent universal vector (termed pAxCALRL. This vector produces recombinant adenoviruses that express the red fluorescent protein (RFP instead of the inserted gene during proliferation, which limits toxicity and can be used to monitor viral replication. Expression of the gene of interest is induced by co-infection with an adenovirus that expresses Cre-recombinase (AxCANCre. Recombinant adenovirus produced by this system that express Hnf4α and Foxa2 were used to reprogram mouse embryo fibroblast (MEF into induced-hepatocyte-like cells (iHep following several rounds of infection, demonstrating the efficacy of this new system.

  7. Chimeric TALE recombinases with programmable DNA sequence specificity.

    Science.gov (United States)

    Mercer, Andrew C; Gaj, Thomas; Fuller, Roberta P; Barbas, Carlos F

    2012-11-01

    Site-specific recombinases are powerful tools for genome engineering. Hyperactivated variants of the resolvase/invertase family of serine recombinases function without accessory factors, and thus can be re-targeted to sequences of interest by replacing native DNA-binding domains (DBDs) with engineered zinc-finger proteins (ZFPs). However, imperfect modularity with particular domains, lack of high-affinity binding to all DNA triplets, and difficulty in construction has hindered the widespread adoption of ZFPs in unspecialized laboratories. The discovery of a novel type of DBD in transcription activator-like effector (TALE) proteins from Xanthomonas provides an alternative to ZFPs. Here we describe chimeric TALE recombinases (TALERs): engineered fusions between a hyperactivated catalytic domain from the DNA invertase Gin and an optimized TALE architecture. We use a library of incrementally truncated TALE variants to identify TALER fusions that modify DNA with efficiency and specificity comparable to zinc-finger recombinases in bacterial cells. We also show that TALERs recombine DNA in mammalian cells. The TALER architecture described herein provides a platform for insertion of customized TALE domains, thus significantly expanding the targeting capacity of engineered recombinases and their potential applications in biotechnology and medicine.

  8. Generation of knock-in mice that express nuclear enhanced green fluorescent protein and tamoxifen-inducible Cre recombinase in the notochord from Foxa2 and T loci.

    Science.gov (United States)

    Imuta, Yu; Kiyonari, Hiroshi; Jang, Chuan-Wei; Behringer, Richard R; Sasaki, Hiroshi

    2013-03-01

    The node and the notochord are important embryonic signaling centers that control embryonic pattern formation. Notochord progenitor cells present in the node and later in the posterior end of the notochord move anteriorly to generate the notochord. To understand the dynamics of cell movement during notochord development and the molecular mechanisms controlling this event, analyses of cell movements using time-lapse imaging and conditional manipulation of gene activities are required. To achieve this goal, we generated two knock-in mouse lines that simultaneously express nuclear enhanced green fluorescent protein (EGFP) and tamoxifen-inducible Cre, CreER(T2) , from two notochord gene loci, Foxa2 and T (Brachury). In Foxa2(nEGFP-CreERT2/+) and T(nEGFP-CreERT2/+) embryos, nuclei of the Foxa2 or T-expressing cells, which include the node, notochord, and endoderm (Foxa2) or wide range of posterior mesoderm (T), were labeled with EGFP at intensities that can be used for live imaging. Cre activity was also induced in cells expressing Foxa2 and T 1 day after tamoxifen administration. These mice are expected to be useful tools for analyzing the mechanisms of notochord development. Copyright © 2013 Wiley Periodicals, Inc.

  9. High-resolution labeling and functional manipulation of specific neuron types in mouse brain by Cre-activated viral gene expression.

    Directory of Open Access Journals (Sweden)

    Sandra J Kuhlman

    2008-04-01

    Full Text Available We describe a method that combines Cre-recombinase knockin mice and viral-mediated gene transfer to genetically label and functionally manipulate specific neuron types in the mouse brain. We engineered adeno-associated viruses (AAVs that express GFP, dsRedExpress, or channelrhodopsin (ChR2 upon Cre/loxP recombination-mediated removal of a transcription-translation STOP cassette. Fluorescent labeling was sufficient to visualize neuronal structures with synaptic resolution in vivo, and ChR2 expression allowed light activation of neuronal spiking. The structural dynamics of a specific class of neocortical neuron, the parvalbumin-containing (Pv fast-spiking GABAergic interneuron, was monitored over the course of a week. We found that although the majority of Pv axonal boutons were stable in young adults, bouton additions and subtractions on axonal shafts were readily observed at a rate of 10.10% and 9.47%, respectively, over 7 days. Our results indicate that Pv inhibitory circuits maintain the potential for structural re-wiring in post-adolescent cortex. With the generation of an increasing number of Cre knockin mice and because viral transfection can be delivered to defined brain regions at defined developmental stages, this strategy represents a general method to systematically visualize the structure and manipulate the function of different cell types in the mouse brain.

  10. Generation of Pet1210-Cre Transgenic Mouse Line Reveals Non-Serotonergic Expression Domains of Pet1 Both in CNS and Periphery

    Science.gov (United States)

    Pelosi, Barbara; Migliarini, Sara; Pacini, Giulia; Pratelli, Marta; Pasqualetti, Massimo

    2014-01-01

    Neurons producing serotonin (5-hydroxytryptamine, 5-HT) constitute one of the most widely distributed neuronal networks in the mammalian central nervous system (CNS) and exhibit a profuse innervation throughout the CNS already at early stages of development. Serotonergic neuron specification is controlled by a combination of secreted molecules and transcription factors such as Shh, Fgf4/8, Nkx2.2, Lmx1b and Pet1. In the mouse, Pet1 mRNA expression appears between 10 and 11 days post coitum (dpc) in serotonergic post-mitotic precursors and persists in serotonergic neurons up to adulthood, where it promotes the expression of genes defining the mature serotonergic phenotype such as tryptophan hydroxylase 2 (Tph2) and serotonin transporter (SERT). Hence, the generation of genetic tools based on Pet1 specific expression represents a valuable approach to study the development and function of the serotonergic system. Here, we report the generation of a Pet1210-Cre transgenic mouse line in which the Cre recombinase is expressed under the control of a 210 kb fragment from the Pet1 genetic locus to ensure a reliable and faithful control of somatic recombination in Pet1 cell lineage. Besides Cre-mediated recombination accurately occurred in the serotonergic system as expected and according to previous studies, Pet1210-Cre transgenic mouse line allowed us to identify novel, so far uncharacterized, Pet1 expression domains. Indeed, we showed that in the raphe Pet1 is expressed also in a non-serotonergic neuronal population intermingled with Tph2-expressing cells and mostly localized in the B8 and B9 nuclei. Moreover, we detected Cre-mediated recombination also in the developing pancreas and in the ureteric bud derivatives of the kidney, where it reflected a specific Pet1 expression. Thus, Pet1210-Cre transgenic mouse line faithfully drives Cre-mediated recombination in all Pet1 expression domains representing a valuable tool to genetically manipulate serotonergic and non

  11. cre siklusu ve kanser

    OpenAIRE

    Cabadak, Hülya

    2008-01-01

    cre çogalması ve hücre siklusunun ilerlemesi büyümenin kontrolünde rolü olan genlerin ekspresyonu ile baglantılıdır. Ökaryot hücre siklusuM(mitoz) G , S ve G fazlarından olusmaktadır. Bu süreçte hücre uyarımı ve büyüme meydana gelir veya hücre G fazında durmaktadır. Hücre siklusunda G -S geçisinde, G -Mgeçisinde ve metafaz-anafaz geçisinde kontrol noktaları bulunmaktadır. Hücre siklusu siklin bagımlı kinazlar (cdk, katalitik altbirim) ve siklin (cyc, düzenleyici altbirim) tarafı...

  12. A Novel Mgp-Cre Knock-In Mouse Reveals an Anticalcification/Antistiffness Candidate Gene in the Trabecular Meshwork and Peripapillary Scleral Region.

    Science.gov (United States)

    Borrás, Teresa; Smith, Matthew H; Buie, LaKisha K

    2015-04-01

    Soft tissue calcification is a pathological condition. Matrix Gla (MGP) is a potent mineralization inhibitor secreted by cartilage chondrocytes and arteries' vascular smooth muscle cells. Mgp knock-out mice die at 6 weeks due to massive arterial calcification. Arterial calcification results in arterial stiffness and higher systolic blood pressure. Intriguingly, MGP was highly abundant in trabecular meshwork (TM). Because tissue stiffness is relevant to glaucoma, we investigated which additional eye tissues use Mgp's function using knock-in mice. An Mgp-Cre-recombinase coding sequence (Cre) knock-in mouse, containing Mgp DNA plus an internal ribosomal entry site (IRES)-Cre-cassette was generated by homologous recombination. Founders were crossed with Cre-mediated reporter mouse R26R-lacZ. Their offspring expresses lacZ where Mgp is transcribed. Eyes from MgpCre/+;R26RlacZ/+ (Mgp-lacZ knock-in) and controls, 1 to 8 months were assayed for β-gal enzyme histochemistry. As expected, Mgp-lacZ knock-in's TM was intensely blue. In addition, this mouse revealed high specific expression in the sclera, particularly in the peripapillary scleral region (ppSC). Ciliary muscle and sclera above the TM were also positive. Scleral staining was located immediately underneath the choroid (chondrocyte layer), began midsclera and was remarkably high in the ppSC. Cornea, iris, lens, ciliary body, and retina were negative. All mice exhibited similar staining patterns. All controls were negative. Matrix Gla's restricted expression to glaucoma-associated tissues from anterior and posterior segments suggests its involvement in the development of the disease. Matrix Gla's anticalcification/antistiffness properties in the vascular tissue, together with its high TM and ppCS expression, place this gene as a strong candidate for TM's softness and sclera's stiffness regulation in glaucoma.

  13. Knockin of Cre Gene at Ins2 Locus Reveals No Cre Activity in Mouse Hypothalamic Neurons.

    Science.gov (United States)

    Li, Ling; Gao, Lin; Wang, Kejia; Ma, Xianhua; Chang, Xusheng; Shi, Jian-Hui; Zhang, Ye; Yin, Kai; Liu, Zhimin; Shi, Yuguang; Xie, Zhifang; Zhang, Weiping J

    2016-02-02

    The recombination efficiency and cell specificity of Cre driver lines are critical for exploring pancreatic β cell biology with the Cre/LoxP approach. Some commonly used Cre lines are based on the short Ins2 promoter fragment and show recombination activity in hypothalamic neurons; however, whether this stems from endogenous Ins2 promoter activity remains controversial. In this study, we generated Ins2-Cre knockin mice with a targeted insertion of IRES-Cre at the Ins2 locus and demonstrated with a cell lineage tracing study that the Ins2 gene is not transcriptionally active in the hypothalamus. The Ins2-Cre driver line displayed robust Cre expression and activity in pancreatic β cells without significant alterations in insulin expression. In the brain, Cre activity was mainly restricted to the choroid plexus, without significant recombination detected in the hippocampus or hypothalamus by the LacZ or fluorescent tdTomato reporters. Furthermore, Ins2-Cre mice exhibited normal glucose tolerance and insulin secretion upon glucose stimulation in vivo. In conclusion, this Ins2-Cre driver line allowed high-fidelity detection of endogenous Ins2 promoter activity in vivo, and the negative activity in the hypothalamus demonstrated that this system is a promising alternative tool for studying β cell biology.

  14. Excision of a viral reprogramming cassette by delivery of synthetic Cre mRNA

    Science.gov (United States)

    Loh, Yuin-Han; Yang, Jimmy Chen; De Los Angeles, Alejandro; Guo, Chunguang; Cherry, Anne; Rossi, Derrick J.; Park, In-Hyun; Daley, George Q.

    2012-01-01

    The generation of patient-specific induced pluripotent stem (iPS) cells provides an invaluable resource for cell therapy, in vitro modeling of human disease, and drug screening. To date, most human iPS cells have been generated with integrating retro- and lenti-viruses and are limited in their potential utility because residual transgene expression may alter their differentiation potential or induce malignant transformation. Alternatively, transgene-free methods using adenovirus and protein transduction are limited by low efficiency. This report describes a protocol for the generation of transgene-free human induced pluripotent stem cells using retroviral transfection of a single vector, which includes the coding sequences of human OCT4, SOX2, KLF4, and cMYC linked with picornaviral 2A plasmids. Moreover, after reprogramming has been achieved, this cassette can be removed using mRNA transfection of Cre recombinase. The method described herein to excise reprogramming factors with ease and efficiency facilitates the experimental generation and use of transgene-free human iPS cells. PMID:22605648

  15. Specific and spatial labeling of P0-Cre versus Wnt1-Cre in cranial neural crest in early mouse embryos.

    Science.gov (United States)

    Chen, Guiqian; Ishan, Mohamed; Yang, Jingwen; Kishigami, Satoshi; Fukuda, Tomokazu; Scott, Greg; Ray, Manas K; Sun, Chenming; Chen, Shi-You; Komatsu, Yoshihiro; Mishina, Yuji; Liu, Hong-Xiang

    2017-06-01

    P0-Cre and Wnt1-Cre mouse lines have been widely used in combination with loxP-flanked mice to label and genetically modify neural crest (NC) cells and their derivatives. Wnt1-Cre has been regarded as the gold standard and there have been concerns about the specificity of P0-Cre because it is not clear about the timing and spatial distribution of the P0-Cre transgene in labeling NC cells at early embryonic stages. We re-visited P0-Cre and Wnt1-Cre models in the labeling of NC cells in early mouse embryos with a focus on cranial NC. We found that R26-lacZ Cre reporter responded to Cre activity more reliably than CAAG-lacZ Cre reporter during early embryogenesis. Cre immunosignals in P0-Cre and reporter (lacZ and RFP) activity in P0-Cre/R26-lacZ and P0-Cre/R26-RFP embryos was detected in the cranial NC and notochord regions in E8.0-9.5 (4-19 somites) embryos. P0-Cre transgene expression was observed in migrating NC cells and was more extensive in the forebrain and hindbrain but not apparent in the midbrain. Differences in the Cre distribution patterns of P0-Cre and Wnt1-Cre were profound in the midbrain and hindbrain regions, that is, extensive in the midbrain of Wnt1-Cre and in the hindbrain of P0-Cre embryos. The difference between P0-Cre and Wnt1-Cre in labeling cranial NC may provide a better explanation of the differential distributions of their NC derivatives and of the phenotypes caused by Cre-driven genetic modifications. © 2017 Wiley Periodicals, Inc.

  16. An X-linked Myh11-CreERT2 mouse line resulting from Y to X chromosome-translocation of the Cre allele.

    Science.gov (United States)

    Liao, Mingmei; Zhou, Junmei; Wang, Fen; Ali, Yasmin H; Chan, Kelvin L; Zou, Fei; Offermanns, Stefan; Jiang, Zhisheng; Jiang, Zhihua

    2017-09-01

    The Myh11-CreER T2 mouse line (Cre + ) has gained increasing application because of its high lineage specificity relative to other Cre drivers targeting smooth muscle cells (SMCs). This Cre allele, however, was initially inserted into the Y chromosome (X/Y Cre+ ), which excluded its application in female mice. Our group established a Cre + colony from male ancestors. Surprisingly, genotype screening identified female carriers that stably transmitted the Cre allele to the following generations. Crossbreeding experiments revealed a pattern of X-linked inheritance for the transgene (k > 1000), indicating that these female carries acquired the Cre allele through a mechanism of Y to X chromosome translocation. Further characterization demonstrated that in hemizygous X/X Cre+ mice Cre activity was restricted to a subset arterial SMCs, with Cre expression in arteries decreased by 50% compared to X/Y Cre+ mice. This mosaicism, however, diminished in homozygous X Cre+ /X Cre+ mice. In a model of aortic aneurysm induced by a SMC-specific Tgfbr1 deletion, the homozygous X Cre+ /X Cre+ Cre driver unmasked the aortic phenotype that is otherwise subclinical when driven by the hemizygous X/X Cre+ Cre line. In conclusion, the Cre allele carried by this female mouse line is located on the X chromosome and subjected to X-inactivation. The homozygous X Cre+ /X Cre+ mice produce uniform Cre activity in arterial SMCs. © 2017 Wiley Periodicals, Inc.

  17. Dwarfism in homozygous Agc1CreERT mice is associated with decreased expression of aggrecan.

    Science.gov (United States)

    Rashid, Harunur; Chen, Haiyan; Hassan, Quamarul; Javed, Amjad

    2017-10-01

    Aggrecan (Acan), a large proteoglycan is abundantly expressed in cartilage tissue. Disruption of Acan gene causes dwarfism and perinatal lethality of homozygous mice. Because of sustained expression of Acan in the growth plate and articular cartilage, Agc Cre model has been developed for the regulated ablation of target gene in chondrocytes. In this model, the IRES-CreERT-Neo-pgk transgene is knocked-in the 3'UTR of the Acan gene. We consistently noticed variable weight and size among the Agc Cre littermates, prompting us to examine the cause of this phenotype. Wild-type, Cre-heterozygous (Agc +/Cre ), and Cre-homozygous (Agc Cre/Cre ) littermates were indistinguishable at birth. However, by 1-month, Agc Cre/Cre mice showed a significant reduction in body weight (18-27%) and body length (19-22%). Low body weight and dwarfism was sustained through adulthood and occurred in both genders. Compared with wild-type and Agc +/Cre littermates, long bones and vertebrae were shorter in Agc Cre/Cre mice. Histological analysis of Agc Cre/Cre mice revealed a significant reduction in the length of the growth plate and the thickness of articular cartilage. The amount of proteoglycan deposited in the cartilage of Agc Cre/Cre mice was nearly half of the WT littermates. Analysis of gene expression indicates impaired differentiation of chondrocyte in hyaline cartilage of Agc Cre/Cre mice. Notably, both Acan mRNA and protein was reduced by 50% in Agc Cre/Cre mice. A strong correlation was noted between the level of Acan mRNA and the body length. Importantly, Agc +/Cre mice showed no overt skeletal phenotype. Thus to avoid misinterpretation of data, only the Agc +/Cre mice should be used for conditional deletion of a target gene in the cartilage tissue. © 2017 Wiley Periodicals, Inc.

  18. Male germline recombination of a conditional allele by the widely used Dermo1-cre (Twist2-cre) transgene.

    Science.gov (United States)

    He, Yun; Sun, Xiumei; Wang, Li; Mishina, Yuji; Guan, Jun-Lin; Liu, Fei

    2017-09-01

    Conditional gene knockout using the Cre/loxP system is instrumental in advancing our understanding of the function of genes in a wide range of disciplines. It is becoming increasingly apparent in the literature that recombination mediated by some Cre transgenes can occur in unexpected tissues. Dermo1-Cre (Twist2-Cre) has been widely used to target skeletal lineage cells as well as other mesoderm-derived cells. Here we report that Dermo1-Cre exhibits spontaneous male germline recombination activity leading to a Cre-mediated recombination of a floxed Ptk2 (Protein tyrosine kinase 2, also known as Fak [Focal adhesion kinase]) allele but not a floxed Rb1cc1 (RB1 inducible coiled-coil 1, also known as Fip200 [FAK-family Interacting Protein of 200 kDa]) allele at high frequency. This ectopic germline activity of Dermo1-Cre occurred in all or none manner in a given litter. We demonstrated that the occurrence of germline recombination activity of Dermo1-Cre transgene can be avoided by using female mice as parental Dermo1-Cre carriers. © 2017 Wiley Periodicals, Inc.

  19. Relationship of the CreBC two-component regulatory system and inner membrane protein CreD with swimming motility in Stenotrophomonas maltophilia.

    Directory of Open Access Journals (Sweden)

    Hsin-Hui Huang

    Full Text Available The CreBC two-component system (TCS is a conserved regulatory system found in Escherichia coli, Aeromonas spp., Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. In this study, we determined how CreBC TCS regulates secreted protease activities and swimming motility using creB, creC, and creBC in-frame deletion mutants (KJΔCreB, KJΔCreC, and KJΔBC of S. maltophilia KJ. Compared to wild-type KJ, KJΔCreB had a comparable secreted protease activity; however, the secreted protease activities were obviously reduced in KJΔCreC and KJΔBC, suggesting that CreC works together with another unidentified response regulator (not CreB to regulate secreted protease activity. Single gene inactivation of creB or creC resulted in mutants with an enhanced swimming motility, and this phenotype was exacerbated in a double mutant KJΔBC. To elucidate the underlying mechanism responsible for the ΔcreBC-mediated swimming enhancement, flagella morphology observation, RNA-seq based transcriptome assay, qRT-PCR, and membrane integrity and potential assessment were performed. Flagella morphological observation ruled out the possibility that swimming enhancement was due to altered flagella morphology. CreBC inactivation upregulated the expression of creD and flagella-associated genes encoding the basal body- and motor-associated proteins. Furthermore, KJΔBC had an increased membrane susceptibility to Triton X-100 and CreD upregulation in KJΔBC partially alleviated the compromise of membrane integrity. The impact of creBC TCS on bacterial membrane potential was assessed by carbonyl cyanide m-chlorophenyl hydrazine (CCCP50 concentration at which 50% of bacterial swimming is inhibited. CCCP50 of wild-type KJ increased when creBC was deleted, indicating an association between the higher membrane potential of KJΔBC cells and enhanced motility. Upregulation of the basal body- and motor-associated genes of flagella in KJΔBC cells may explain the increased

  20. Risk Factors for Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae (CP-CRE) Acquisition Among Contacts of Newly Diagnosed CP-CRE Patients.

    Science.gov (United States)

    Schwartz-Neiderman, Anat; Braun, Tali; Fallach, Noga; Schwartz, David; Carmeli, Yehuda; Schechner, Vered

    2016-10-01

    OBJECTIVE Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) are extremely drug-resistant pathogens. Screening of contacts of newly identified CP-CRE patients is an important step to limit further transmission. We aimed to determine the risk factors for CP-CRE acquisition among patients exposed to a CP-CRE index patient. METHODS A matched case-control study was performed in a tertiary care hospital in Israel. The study population was comprised of patients who underwent rectal screening for CP-CRE following close contact with a newly identified CP-CRE index patient. Cases were defined as positive tests for CP-CRE. For each case patient, 2 matched controls were randomly selected from the pool of contacts who tested negative for CP-CRE following exposure to the same index case. Bivariate and multivariate analyses were conducted using conditional logistic regression. RESULTS In total, 53 positive contacts were identified in 40 unique investigations (896 tests performed on 735 contacts) between October 6, 2008, and June 7, 2012. bla KPC was the only carbapenemase identified. In multivariate analysis, risk factors for CP-CRE acquisition among contacts were (1) contact with an index patient for ≥3 days (odds ratio [OR], 9.8; 95% confidence interval [CI], 2.0-48.9), (2) mechanical ventilation (OR, 4.1; 95% CI, 1.4-11.9), and (3) carriage or infection with another multidrug-resistant organism (MDRO; OR, 2.6; 95% CI, 1.0-7.1). Among patients who received antibiotics, cephalosporins were associated with a lower risk of acquisition. CONCLUSIONS Patient characteristics (ventilation and carriage of another MDRO) as well as duration of contact are risk factors for CP-CRE acquisition among contacts. The role of cephalosporins requires further study. Infect Control Hosp Epidemiol 2016;1-7.

  1. Osterix-Cre transgene causes craniofacial bone development defect

    Science.gov (United States)

    Wang, Li; Mishina, Yuji; Liu, Fei

    2015-01-01

    The Cre/loxP system has been widely used to generate tissue-specific gene knockout mice. Inducible (Tet-off) Osx-GFP::Cre (Osx-Cre) mouse line that targets osteoblasts is widely used in the bone research field. In this study, we investigated the effect of Osx-Cre on craniofacial bone development. We found that newborn Osx-Cre mice showed severe hypomineralization in parietal, frontal, and nasal bones as well as the coronal sutural area when compared to control mice. As the mice matured the intramembranous bone hypomineralization phenotype became less severe. The major hypomineralization defect in parietal, frontal, and nasal bones had mostly disappeared by postnatal day 21, but the defect in sutural areas persisted. Importantly, Doxycycline treatment eliminated cranial bone defects at birth which indicates that Cre expression may be responsible for the phenotype. In addition, we showed that the primary calvarial osteoblasts isolated from neonatal Osx-Cre mice had comparable differentiation ability compared to their littermate controls. This study reinforces the idea that Cre positive litter mates are indispensable controls in studies using conditional gene deletion. PMID:25550101

  2. Homologous Recombination in Protozoan Parasites and Recombinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Andrew A. Kelso

    2017-09-01

    Full Text Available Homologous recombination (HR is a DNA double-strand break (DSB repair pathway that utilizes a homologous template to fully repair the damaged DNA. HR is critical to maintain genome stability and to ensure genetic diversity during meiosis. A specialized class of enzymes known as recombinases facilitate the exchange of genetic information between sister chromatids or homologous chromosomes with the help of numerous protein accessory factors. The majority of the HR machinery is highly conserved among eukaryotes. In many protozoan parasites, HR is an essential DSB repair pathway that allows these organisms to adapt to environmental conditions and evade host immune systems through genetic recombination. Therefore, small molecule inhibitors, capable of disrupting HR in protozoan parasites, represent potential therapeutic options. A number of small molecule inhibitors were identified that disrupt the activities of the human recombinase RAD51. Recent studies have examined the effect of two of these molecules on the Entamoeba recombinases. Here, we discuss the current understandings of HR in the protozoan parasites Trypanosoma, Leishmania, Plasmodium, and Entamoeba, and we review the small molecule inhibitors known to disrupt human RAD51 activity.

  3. Increased production of biomass-degrading enzymes by double deletion of creA and creB genes involved in carbon catabolite repression in Aspergillus oryzae.

    Science.gov (United States)

    Ichinose, Sakurako; Tanaka, Mizuki; Shintani, Takahiro; Gomi, Katsuya

    2018-02-01

    In a previous study, we reported that a double gene deletion mutant for CreA and CreB, which constitute the regulatory machinery involved in carbon catabolite repression, exhibited improved production of α-amylase compared with the wild-type strain and single creA or creB deletion mutants in Aspergillus oryzae. Because A. oryzae can also produce biomass-degrading enzymes, such as xylolytic and cellulolytic enzymes, we examined the production levels of those enzymes in deletion mutants in this study. Xylanase and β-glucosidase activities in the wild-type were hardly detected in submerged culture containing xylose as the carbon source, whereas those enzyme activities were significantly increased in the single creA deletion (ΔcreA) and double creA and creB deletion (ΔcreAΔcreB) mutants. In particular, the ΔcreAΔcreB mutant exhibited >100-fold higher xylanase and β-glucosidase activities than the wild-type. Moreover, in solid-state culture, the β-glucosidase activity of the double deletion mutant was >7-fold higher than in the wild-type. These results suggested that deletion of both creA and creB genes could also efficiently improve the production levels of biomass-degrading enzymes in A. oryzae. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. A novel genetic tool for metabolic optimization of Corynebacterium glutamicum: efficient and repetitive chromosomal integration of synthetic promoter-driven expression libraries

    DEFF Research Database (Denmark)

    Shen, Jing; Chen, Jun; Jensen, Peter Ruhdal

    2017-01-01

    readily could integrate into the attB site in this strain providing expression of the corresponding integrase. Subsequent expression of the Cre recombinase promoted recombination between the modified loxP sites, resulting in a strain only retaining the target insertions and an attB site. To simplify...... the procedure, non-replicating circular expression units for the phage integrase and the Cre recombinase were used. As a showcase, we used the tool to construct a battery of strains simultaneously expressing the two reporter genes, lacZ (encoding β-galactosidase) and gusA (encoding β...

  5. Cereal cyst nematode resistance conferred by the Cre7 gene from Aegilops triuncialis and its relationship with Cre genes from Australian wheat cultivars

    OpenAIRE

    Montes, Maria Jesus; Andrés, María Fe; Sin, E.; Lopez Braña, Isidoro; Martín-Sánchez, J.A.; Romero, M.D.; Delibes Castro, Angeles

    2008-01-01

    Cereal cyst nematode (CCN; Heterodera avenae Woll.) is a root pathogen of cereal crops that can cause severe yield losses in wheat (Triticum aestivum). Differential host–nematode interactions occur in wheat cultivars carrying different CCN resistance (Cre) genes. The objective of this study was to determine the CCN resistance conferred by the Cre7 gene from Aegilops triuncialis in a 42-chromosome introgression line and to assess the effects of the Cre1, Cre3, Cre4, and Cre8 genes present in A...

  6. Cre-/IoxP-Mediated Recombination between the SIL and SCL Genes Leads to a Block in T-Cell Development at the CD4-CD8- to CD4+CD8+ Transition

    Directory of Open Access Journals (Sweden)

    Yue Cheng

    2007-04-01

    Full Text Available In the most common form of stem cell leukemia (SCL gene rearrangement, an interstitial deletion of 82 kb brings SCL under the control of regulatory elements that normally govern expression of the ubiquitously expressed SCL interrupting locus (SIL gene, which is located directly upstream of SCL. To investigate the effect of this fusion in a mouse model, a bacterial artificial chromosome (BAC clone containing both human SIL and SCL genes was isolated, and IoxP sites were inserted into intron 1 of both the SIL and SCL genes, corresponding to the sites at which recombination occurs in human T-cell acute lymphocytic leukemia patients. This BAC clone was used to generate transgenic SILIoxloxSCL mice. These transgenic mice were subsequently bred to Lck-Cre mice that express the Cre recombinase specifically in the thymus. The BAC transgene was recombined between the two IoxP sites in over 50% of the thymocytes from SILIoxloxSCL/Cre double-transgenic mice, bringing the SCL gene under the direct control of SIL regulatory elements. Aberrant SCL gene expression in the thymus was verified by reverse transcription- polymerase chain reaction. Using FACS analysis, we found that mice carrying both SILIoxloxSCL and Cre transgenes have increased CD4-/CD8- thymocytes compared with transgenenegative mice. In the spleen, these transgenic mice show a marked reduction in the number of mature CD4+ or CD8+ cells. These results demonstrate that conditional activation of SCL under control of SIL regulatory elements can impair normal T-cell development.

  7. Excision of HIV-1 proviral DNA by recombinant cell permeable tre-recombinase.

    Directory of Open Access Journals (Sweden)

    Lakshmikanth Mariyanna

    Full Text Available Over the previous years, comprehensive studies on antiretroviral drugs resulted in the successful introduction of highly active antiretroviral therapy (HAART into clinical practice for treatment of HIV/AIDS. However, there is still need for new therapeutic approaches, since HAART cannot eradicate HIV-1 from the infected organism and, unfortunately, can be associated with long-term toxicity and the development of drug resistance. In contrast, novel gene therapy strategies may have the potential to reverse the infection by eradicating HIV-1. For example, expression of long terminal repeat (LTR-specific recombinase (Tre-recombinase has been shown to result in chromosomal excision of proviral DNA and, in consequence, in the eradication of HIV-1 from infected cell cultures. However, the delivery of Tre-recombinase currently depends on the genetic manipulation of target cells, a process that is complicating such therapeutic approaches and, thus, might be undesirable in a clinical setting. In this report we demonstrate that E.coli expressed Tre-recombinases, tagged either with the protein transduction domain (PTD from the HIV-1 Tat trans-activator or the translocation motif (TLM of the Hepatitis B virus PreS2 protein, were able to translocate efficiently into cells and showed significant recombination activity on HIV-1 LTR sequences. Tre activity was observed using episomal and stable integrated reporter constructs in transfected HeLa cells. Furthermore, the TLM-tagged enzyme was able to excise the full-length proviral DNA from chromosomal integration sites of HIV-1-infected HeLa and CEM-SS cells. The presented data confirm Tre-recombinase activity on integrated HIV-1 and provide the basis for the non-genetic transient application of engineered recombinases, which may be a valuable component of future HIV eradication strategies.

  8. Stereospecific suppression of active site mutants by methylphosphonate substituted substrates reveals the stereochemical course of site-specific DNA recombination

    OpenAIRE

    Rowley, Paul A.; Kachroo, Aashiq H.; Ma, Chien-Hui; Maciaszek, Anna D.; Guga, Piotr; Jayaram, Makkuni

    2015-01-01

    Tyrosine site-specific recombinases, which promote one class of biologically important phosphoryl transfer reactions in DNA, exemplify active site mechanisms for stabilizing the phosphate transition state. A highly conserved arginine duo (Arg-I; Arg-II) of the recombinase active site plays a crucial role in this function. Cre and Flp recombinase mutants lacking either arginine can be rescued by compensatory charge neutralization of the scissile phosphate via methylphosphonate (MeP) modificati...

  9. Multicenter Clinical and Molecular Epidemiological Analysis of Bacteremia Due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE Epicenter of the United States

    Science.gov (United States)

    Chen, Liang; Patel, Gopi; Gomez-Simmonds, Angela; Weston, Gregory; Kim, Angela C.; Seo, Susan K.; Rosenthal, Marnie E.; Sperber, Steven J.; Jenkins, Stephen G.; Hamula, Camille L.; Uhlemann, Anne-Catrin; Levi, Michael H.; Fries, Bettina C.; Juretschko, Stefan; Rojtman, Albert D.; Hong, Tao; Mathema, Barun; Jacobs, Michael R.; Walsh, Thomas J.; Bonomo, Robert A.; Kreiswirth, Barry N.

    2017-01-01

    ABSTRACT Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics. PMID:28167547

  10. Tissue-specifically regulated site-specific excision of selectable marker genes in bivalent insecticidal, genetically-modified rice.

    Science.gov (United States)

    Hu, Zhan; Ding, Xuezhi; Hu, Shengbiao; Sun, Yunjun; Xia, Liqiu

    2013-12-01

    Marker-free, genetically-modified rice was created by the tissue-specifically regulated Cre/loxP system, in which the Cre recombinase gene and hygromycin phosphotransferase gene (hpt) were flanked by two directly oriented loxP sites. Cre expression was activated by the tissue-specific promoter OsMADS45 in flower or napin in seed, resulting in simultaneous excision of the recombinase and marker genes. Segregation of T1 progeny was performed to select recombined plants. The excision was confirmed by PCR, Southern blot and sequence analyses indicating that efficiency varied from 10 to 53 % for OsMADS45 and from 12 to 36 % for napin. The expression of cry1Ac and vip3A was detected by RT-PCR analysis in marker-free transgenic rice. These results suggested that our tissue-specifically regulated Cre/loxP system could auto-excise marker genes from transgenic rice and alleviate public concerns about the security of GM crops.

  11. Conditional Gene Expression in the Mouse Inner Ear Using Cre-loxP

    OpenAIRE

    Cox, Brandon C.; Liu, Zhiyong; Lagarde, Marcia M. Mellado; Zuo, Jian

    2012-01-01

    In recent years, there has been significant progress in the use of Cre-loxP technology for conditional gene expression in the inner ear. Here, we introduce the basic concepts of this powerful technology, emphasizing the differences between Cre and CreER. We describe the creation and Cre expression pattern of each Cre and CreER mouse line that has been reported to have expression in auditory and vestibular organs. We compare the Cre expression patterns between Atoh1-CreERTM and Atoh1-CreERT2 a...

  12. Building Cre Knockin Rat Lines Using CRISPR/Cas9.

    Science.gov (United States)

    Ma, Yuanwu; Zhang, Lianfeng; Huang, Xingxu

    2017-01-01

    Conditional gene inactivation strategy helps researchers to study the gene functions that are critical in embryogenesis or in defined tissues of adulthood. The Cre/loxP system is widely used for conditional gene inactivation/activation in cells or organisms. Cre knockin animal lines are essential for gene expression or inactivation in a spatially and temporally restricted manner. However, to generate a Cre knockin line by traditional approach is laborious. Recently, the clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) has been proven as a simple and efficient genome-editing tool. We have used CRISPR/Cas9 system to generate rat strains that carry Cre genes in different targeted gene loci by direct delivery of gRNAs/Cas9/donors into fertilized eggs. Here, we described a stepwise procedure for the generation of Cre knockin rat, including target site selection, RNA preparation, the construction of the template donor, pronuclear injection, and the genotyping of precise Cre insertion in F 0 rats. Taken together, the establishment of Cre knockin line can be achieved within 6 weeks.

  13. Commission for Energy regulation (CRE) - Activity report June 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2007 activity report of CRE. Content: A - Towards a single European energy market: Birth of a single European energy market (Origins of Europe of Energy, Emergence of a European energy policy); Main European Community guiding lines (European governance as regards energy, Guiding principles for the internal energy market); European Community activities (European Commission reports, Electricity and gas Regional Initiatives); Organisation and coordination of European regulators (Joint organisation of European regulators, CRE's relations with European Community institutions); CRE's European activities (Regional integration of gas markets, Regional integration of electricity markets, Operation of the European interconnected electricity grid and security of supply, CRE's other European activities); B - CRE action at national level: Grids/networks and infrastructures (General information, Electricity grids, Regulation of gas networks and infrastructures); Markets (Changes in the regulatory and legislative contexts of electricity and natural gas markets, Electricity markets

  14. Commission for Energy regulation (CRE) - Activity report June 2007

    International Nuclear Information System (INIS)

    2007-01-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2007 activity report of CRE. Content: A - Towards a single European energy market: Birth of a single European energy market (Origins of Europe of Energy, Emergence of a European energy policy); Main European Community guiding lines (European governance as regards energy, Guiding principles for the internal energy market); European Community activities (European Commission reports, Electricity and gas Regional Initiatives); Organisation and coordination of European regulators (Joint organisation of European regulators, CRE's relations with European Community institutions); CRE's European activities (Regional integration of gas markets, Regional integration of electricity markets, Operation of the European interconnected electricity grid and security of supply, CRE's other European activities); B - CRE action at national level: Grids/networks and infrastructures (General information, Electricity grids, Regulation of gas networks and infrastructures); Markets (Changes in the regulatory and legislative contexts of electricity and natural gas markets, Electricity markets, Natural gas

  15. Multicenter Clinical and Molecular Epidemiological Analysis of Bacteremia Due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE Epicenter of the United States.

    Science.gov (United States)

    Satlin, Michael J; Chen, Liang; Patel, Gopi; Gomez-Simmonds, Angela; Weston, Gregory; Kim, Angela C; Seo, Susan K; Rosenthal, Marnie E; Sperber, Steven J; Jenkins, Stephen G; Hamula, Camille L; Uhlemann, Anne-Catrin; Levi, Michael H; Fries, Bettina C; Tang, Yi-Wei; Juretschko, Stefan; Rojtman, Albert D; Hong, Tao; Mathema, Barun; Jacobs, Michael R; Walsh, Thomas J; Bonomo, Robert A; Kreiswirth, Barry N

    2017-04-01

    Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types ( cps ), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae , Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC- Kp ). The wzi154 allele, corresponding to cps-2 , was present in 93% of KPC-3- Kp , whereas KPC-2- Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3- Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3- Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics. Copyright © 2017 American Society for Microbiology.

  16. Cardiac-specific activation of Cre expression at late fetal development

    International Nuclear Information System (INIS)

    Opherk, Jan P.; Yampolsky, Peter; Hardt, Stefan E.; Schoels, Wolfgang; Katus, Hugo A.; Koenen, Michael; Zehelein, Joerg

    2007-01-01

    In a first step towards dissecting molecular mechanisms that contribute to the development of cardiac diseases, we have generated transgenic mice that express a Cre-GFP fusion protein under the transcriptional control of a 4.3 kb murine cardiac Troponin I gene (cTnI) promoter. Cre-GFP expression, similar in three transgenic lines, is described in one line. In mouse embryos, transgenic for the Cre-GFP and ROSA lacZ reporter allele, first Cre-mediated recombination appeared at 16.5 dpc selectively at the heart. Like the endogenous cTnI gene, transgenic Cre expression showed a slow rise through fetal development that increased neonatally. Bitransgenic hearts, stained at 30 days of age, showed intense signals in ventricular and atrial myocytes while no recombination occurred in other tissues. The delayed onset of Cre activity in cTnI-Cre mice could provide a useful genetic tool to evaluate the function of loxP targeted cardiac genes without interference of recombination during early heart development

  17. Somatostatin-IRES-Cre Mice: Between Knockout and Wild-Type?

    Science.gov (United States)

    Viollet, Cécile; Simon, Axelle; Tolle, Virginie; Labarthe, Alexandra; Grouselle, Dominique; Loe-Mie, Yann; Simonneau, Michel; Martel, Guillaume; Epelbaum, Jacques

    2017-01-01

    The neuropeptide somatostatin (SOM) is widely expressed in rodent brain and somatostatin-IRES-Cre (SOM-cre) mouse strains are increasingly used to unravel the physiology of SOM-containing neurons. However, while knock-in targeting strategy greatly improves Cre-Lox system accuracy, recent reports have shown that genomic insertion of Cre construct per se can markedly affect physiological function. We show that Cre transgene insertion into the 3'UTR of the somatostatin gene leads to the selective and massive depletion of endogenous SOM in all tested brain regions. It also strongly impacts SOM-related neuroendocrine responses in a similar manner to what has been reported for SST KO mice: increased corticosterone levels after 30-min restraint stress, decreased amplitude and regularity of ultradian growth hormone secretory patterns accompanied by changes in sexually dimorphic liver gene expression ( serpina1, Cyp2b9, Cyp2a4, Cyp2d9, and Cyp7b1 ). In addition to demonstrating the need for examination of the consequences of Cre transgenesis, these results also reveal how this SOM-cre strain may be a useful tool in studying the functional consequences of moderate to low SOM levels as reported in neurological and psychiatric disorders.

  18. Tg(Th-Cre)FI172Gsat (Th-Cre) defines neurons that are required for full hypercapnic and hypoxic reflexes.

    Science.gov (United States)

    Sun, Jenny J; Ray, Russell S

    2017-08-15

    The catecholaminergic (CA) system has been implicated in many facets of breathing control and offers an important target to better comprehend the underlying etiologies of both developmental and adult respiratory pathophysiologies. Here, we used a noninvasive DREADD-based pharmacogenetic approach to acutely perturb Tg(Th-Cre)FI172Gsat ( Th-Cre )-defined neurons in awake and unrestrained mice in an attempt to characterize CA function in breathing. We report that clozapine-N-oxide (CNO)-DREADD-mediated inhibition of Th-Cre -defined neurons results in blunted ventilatory responses under respiratory challenge. Under a hypercapnic challenge (5% CO 2 /21% O 2 /74% N 2 ), perturbation of Th-Cre neurons results in reduced f R , [Formula: see text] and [Formula: see text] Under a hypoxic challenge (10% O 2 /90% N 2 ), we saw reduced f R , [Formula: see text] and [Formula: see text], in addition to instability in both interbreath interval and tidal volume, resulting in a Cheyne-Stokes-like respiratory pattern. These findings demonstrate the necessity of Th-Cre -defined neurons for the hypercapnic and hypoxic ventilatory responses and breathing stability during hypoxia. However, given the expanded non-CA expression domains of the Tg(Th-Cre)FI172Gsat mouse line found in the brainstem, full phenotypic effect cannot be assigned solely to CA neurons. Nonetheless, this work identifies a key respiratory population that may lead to further insights into the circuitry that maintains respiratory stability in the face of homeostatic challenges. © 2017. Published by The Company of Biologists Ltd.

  19. Extracellular vesicle-mediated transfer of genetic information between the hematopoietic system and the brain in response to inflammation.

    Directory of Open Access Journals (Sweden)

    Kirsten Ridder

    2014-06-01

    Full Text Available Mechanisms behind how the immune system signals to the brain in response to systemic inflammation are not fully understood. Transgenic mice expressing Cre recombinase specifically in the hematopoietic lineage in a Cre reporter background display recombination and marker gene expression in Purkinje neurons. Here we show that reportergene expression in neurons is caused by intercellular transfer of functional Cre recombinase messenger RNA from immune cells into neurons in the absence of cell fusion. In vitro purified secreted extracellular vesicles (EVs from blood cells contain Cre mRNA, which induces recombination in neurons when injected into the brain. Although Cre-mediated recombination events in the brain occur very rarely in healthy animals, their number increases considerably in different injury models, particularly under inflammatory conditions, and extend beyond Purkinje neurons to other neuronal populations in cortex, hippocampus, and substantia nigra. Recombined Purkinje neurons differ in their miRNA profile from their nonrecombined counterparts, indicating physiological significance. These observations reveal the existence of a previously unrecognized mechanism to communicate RNA-based signals between the hematopoietic system and various organs, including the brain, in response to inflammation.

  20. Infection control implications of heterogeneous resistance mechanisms in carbapenem-resistant Enterobacteriaceae (CRE).

    Science.gov (United States)

    Goodman, K E; Simner, P J; Tamma, P D; Milstone, A M

    2016-01-01

    The Centers for Disease Control and Prevention (CDC) defines carbapenem-resistant Enterobacteriaceae (CRE) based upon a phenotypic demonstration of carbapenem resistance. However, considerable heterogeneity exists within this definitional umbrella. CRE may mechanistically differ by whether they do or do not produce carbapenemases. Moreover, patients can acquire CRE through multiple pathways: endogenously through antibiotic selective pressure on intestinal microbiota, exogenously through horizontal transmission or through a combination of these factors. Some evidence suggests that non-carbapenemase-producing CRE may be more frequently acquired by antibiotic exposure and carbapenemase-producing CRE via horizontal transmission, but definitive data are lacking. This review examines types of CRE resistance mechanisms, antibiotic exposure and horizontal transmission pathways of CRE acquisition, and the implications of these heterogeneities to the development of evidence-based CRE healthcare epidemiology policies. In our Expert Commentary & Five-Year View, we outline specific nosocomial CRE knowledge gaps and potential methodological approaches for their resolution.

  1. Tamoxifen dosing for Cre-mediated recombination in experimental bronchopulmonary dysplasia.

    Science.gov (United States)

    Ruiz-Camp, Jordi; Rodríguez-Castillo, José Alberto; Herold, Susanne; Mayer, Konstantin; Vadász, István; Tallquist, Michelle D; Seeger, Werner; Ahlbrecht, Katrin; Morty, Rory E

    2017-02-01

    Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth characterized by blunted post-natal lung development. BPD can be modelled in mice by exposure of newborn mouse pups to elevated oxygen levels. Little is known about the mechanisms of perturbed lung development associated with BPD. The advent of transgenic mice, where genetic rearrangements can be induced in particular cell-types at particular time-points during organogenesis, have great potential to explore the pathogenic mechanisms at play during arrested lung development. Many inducible, conditional transgenic technologies available rely on the application of the estrogen-receptor modulator, tamoxifen. While tamoxifen is well-tolerated and has been widely employed in adult mice, or in healthy developing mice; tamoxifen is not well-tolerated in combination with hyperoxia, in the most widely-used mouse model of BPD. To address this, we set out to establish a safe and effective tamoxifen dosing regimen that can be used in newborn mouse pups subjected to injurious stimuli, such as exposure to elevated levels of environmental oxygen. Our data reveal that a single intraperitoneal dose of tamoxifen of 0.2 mg applied to newborn mouse pups in 10 μl Miglyol vehicle was adequate to successfully drive Cre recombinase-mediated genome rearrangements by the fifth day of life, in a murine model of BPD. The number of recombined cells was comparable to that observed in regular tamoxifen administration protocols. These findings will be useful to investigators where tamoxifen dosing is problematic in the background of injurious stimuli and mouse models of human and veterinary disease.

  2. Lack of functional specialization of neurons in the mouse primary visual cortex that have expressed calretinin

    Directory of Open Access Journals (Sweden)

    Daniela eCamillo

    2014-09-01

    Full Text Available Calretinin is a calcium-binding protein often used as a marker for a subset of inhibitory interneurons in the mammalian neocortex. We studied the labeled cells in offspring from a cross of a Cre-dependent reporter line with the CR-ires-Cre mice, which express Cre-recombinase in the same pattern as calretinin. We found that in the mature visual cortex, only a minority of the cells that have expressed calretinin and Cre-recombinase during their lifetime is GABAergic and only about 20% are immunoreactive for calretinin. The reason behind this is that calretinin is transiently expressed in many cortical pyramidal neurons during development. To determine whether neurons that express or have expressed calretinin share any distinct functional characteristics, we recorded their visual response properties using GCaMP6s calcium imaging. The average orientation selectivity, size tuning, and temporal and spatial frequency tuning of this group of cells, however, match the response profile of the general neuronal population, revealing the lack of functional specialization for the features studied.

  3. Cre-loxP-Mediated Recombination: General Principles and Experimental Considerations.

    Science.gov (United States)

    McLellan, Micheal A; Rosenthal, Nadia A; Pinto, Alexander R

    2017-03-02

    The cre-loxP-mediated recombination system (the "cre-loxP system") is an integral experimental tool for mammalian genetics and cell biology. Use of the system has greatly expanded our ability to precisely interrogate gene function in the mouse, providing both spatial and temporal control of gene expression. This has been largely due to the simplicity of its use and its adaptability to address diverse biological questions. While the use of the cre-loxP system is becoming increasingly widespread, in particular because of growing availability of conditional mouse mutants, many considerations need to be taken into account when utilizing the cre-loxP system. This review provides an overview of the cre-loxP system and its various permutations. It addresses the limitations of cre-loxP technology and related considerations for experimental design, and it discusses alternative strategies for site-specific genetic recombination and integration. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. Expression and Functions of CreD, an Inner Membrane Protein in Stenotrophomonas maltophilia

    OpenAIRE

    Huang, Hsin-Hui; Lin, Yi-Tsung; Chen, Wei-Ching; Huang, Yi-Wei; Chen, Shiang-Jiuun; Yang, Tsuey-Ching

    2015-01-01

    CreBC is a highly conserved two-component regulatory system (TCS) in several gram-negative bacteria, including Escherichia coli, Aeromonas spp., Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. CreD is a conserved gene that encodes a predicted inner-membrane protein and is located near the creBC loci. Activation of CreBC increases creD expression; therefore, creD expression is generally used as a measure of CreBC activation in E. coli, Aeromonas spp., and P. aeruginosa systems. In th...

  5. Commission for Energy regulation (CRE) - Activity report june 2008; Commission de regulation de l'energie (CRE) - Rapport d'activite juin 2008

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2008 activity report of CRE. Content: A - How CRE works: CRE regulatory authority and organisation: Powers, Organisation; Budget resources; Personnel; B - The Standing Committee for Dispute Settlement and Sanctions (CoRDiS) activity: Admissibility, Authority; C - Building a single European energy market: Overview; Organisation and coordination of the main European regulators (Work carried out collectively by European regulators, Regulator organisation and development, CRE's relations with European Community institutions, Development of CEER activities outside the European Union); CRE's European activities (The contribution of European regulators to the Third Energy Package, Integration of gas markets, Integration of electricity markets, Operation of the European interconnected electricity grid and security of supply, Opening up markets to benefit consumers); European Community activities (The European Commission's proposals for the internal energy market: the Third Energy Package, The European Commission's proposals for fighting climate change: the Climate Package, Infringement

  6. Regulation of glycogen metabolism by the CRE-1, RCO-1 and RCM-1 proteins in Neurospora crassa. The role of CRE-1 as the central transcriptional regulator.

    Science.gov (United States)

    Cupertino, Fernanda Barbosa; Virgilio, Stela; Freitas, Fernanda Zanolli; Candido, Thiago de Souza; Bertolini, Maria Célia

    2015-04-01

    The transcription factor CreA/Mig1/CRE-1 is a repressor protein that regulates the use of alternative carbon sources via a mechanism known as Carbon Catabolite Repression (CCR). In Saccharomyces cerevisiae, Mig1 recruits the complex Ssn6-Tup1, the Neurospora crassa RCM-1 and RCO-1 orthologous proteins, respectively, to bind to promoters of glucose-repressible genes. We have been studying the regulation of glycogen metabolism in N. crassa and the identification of the RCO-1 corepressor as a regulator led us to investigate the regulatory role of CRE-1 in this process. Glycogen content is misregulated in the rco-1(KO), rcm-1(RIP) and cre-1(KO) strains, and the glycogen synthase phosphorylation is decreased in all strains, showing that CRE-1, RCO-1 and RCM-1 proteins are involved in glycogen accumulation and in the regulation of GSN activity by phosphorylation. We also confirmed the regulatory role of CRE-1 in CCR and its nuclear localization under repressing condition in N. crassa. The expression of all glycogenic genes is misregulated in the cre-1(KO) strain, suggesting that CRE-1 also controls glycogen metabolism by regulating gene expression. The existence of a high number of the Aspergillus nidulans CreA motif (5'-SYGGRG-3') in the glycogenic gene promoters led us to analyze the binding of CRE-1 to some DNA motifs both in vitro by DNA gel shift and in vivo by ChIP-qPCR analysis. CRE-1 bound in vivo to all motifs analyzed demonstrating that it down-regulates glycogen metabolism by controlling gene expression and GSN phosphorylation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Nrl-Cre transgenic mouse mediates loxP recombination in developing rod photoreceptors.

    Science.gov (United States)

    Brightman, Diana S; Razafsky, David; Potter, Chloe; Hodzic, Didier; Chen, Shiming

    2016-03-01

    The developing mouse retina is a tractable model for studying neurogenesis and differentiation. Although transgenic Cre mouse lines exist to mediate conditional genetic manipulations in developing mouse retinas, none of them act specifically in early developing rods. For conditional genetic manipulations of developing retinas, a Nrl-Cre mouse line in which the Nrl promoter drives expression of Cre in rod precursors was created. The results showed that Nrl-Cre expression was specific to the retina where it drives rod-specific recombination with a temporal pattern similar to endogenous Nrl expression during retinal development. This Nrl-Cre transgene does not negatively impact retinal structure and function. Taken together, the data suggested that the Nrl-Cre mouse line was a valuable tool to drive Cre-mediated recombination specifically in developing rods. © 2016 Wiley Periodicals, Inc.

  8. The effect of conditional inactivation of beta 1 integrins using twist 2 Cre, Osterix Cre and osteocalcin Cre lines on skeletal phenotype.

    Science.gov (United States)

    Shekaran, Asha; Shoemaker, James T; Kavanaugh, Taylor E; Lin, Angela S; LaPlaca, Michelle C; Fan, Yuhong; Guldberg, Robert E; García, Andrés J

    2014-11-01

    Skeletal development and growth are complex processes regulated by multiple microenvironmental cues, including integrin-ECM interactions. The β1 sub-family of integrins is the largest integrin sub-family and constitutes the main integrin binding partners of collagen I, the major ECM component of bone. As complete β1 integrin knockout results in embryonic lethality, studies of β1 integrin function in vivo rely on tissue-specific gene deletions. While multiple in vitro studies indicate that β1 integrins are crucial regulators of osteogenesis and mineralization, in vivo osteoblast-specific perturbations of β1 integrins have resulted in mild and sometimes contradictory skeletal phenotypes. To further investigate the role of β1 integrins on skeletal phenotype, we used the Twist2-Cre, Osterix-Cre and osteocalcin-Cre lines to generate conditional β1 integrin deletions, where Cre is expressed primarily in mesenchymal condensation, pre-osteoblast, and mature osteoblast lineage cells respectively within these lines. Mice with Twist2-specific β1 integrin disruption were smaller, had impaired skeletal development, especially in the craniofacial and vertebral tissues at E19.5, and did not survive beyond birth. Osterix-specific β1 integrin deficiency resulted in viable mice which were normal at birth but displayed early defects in calvarial ossification, incisor eruption and growth as well as femoral bone mineral density, structure, and mechanical properties. Although these defects persisted into adulthood, they became milder with age. Finally, a lack of β1 integrins in mature osteoblasts and osteocytes resulted in minor alterations to femur structure but had no effect on mineral density, biomechanics or fracture healing. Taken together, our data indicate that β1 integrin expression in early mesenchymal condensations play an important role in skeletal ossification, while β1 integrin-ECM interactions in pre-osteoblast, odontoblast- and hypertrophic chondryocyte

  9. Beyond knockouts: cre resources for conditional mutagenesis

    Science.gov (United States)

    Murray, Stephen A.; Eppig, Janan T.; Smedley, Damian; Simpson, Elizabeth M.; Rosenthal, Nadia

    2013-01-01

    With the effort of the International Phenotyping Consortium (IMPC) to produce thousands of strains with conditional potential gathering steam, there is growing recognition that it must be supported by a rich toolbox of cre driver strains. The approaches to build cre strains have evolved in both sophistication and reliability, replacing first generation strains with tools that can target individual cell populations with incredible precision and specificity. The modest set of cre drivers generated by individual labs over the past 15+ years is now growing rapidly, thanks to a number of large-scale projects to produce new cre strains for the community. The power of this growing resource, however, depends upon the proper deep characterization of strain function, as even the best designed strain can display a variety of undesirable features that must be considered in experimental design. This must be coupled with the parallel development of informatics tools to provide functional data to the user, and facilitated access to the strains through public repositories. We will discuss the current progress on all of these fronts and the challenges that remain to ensure the scientific community can capitalize on the tremendous number of mouse resources at their disposal. PMID:22926223

  10. Hydrodynamic Delivery of Cre Protein to Lineage-Mark or Time-Stamp Mouse Hepatocytes In situ

    Science.gov (United States)

    Sonsteng, Katherine M.; Prigge, Justin R.; Talago, Emily A.; June, Ronald K.; Schmidt, Edward E.

    2014-01-01

    Cre-responsive fluorescent marker alleles are powerful tools for cell lineage tracing in mice; however their utility is limited by regulation of Cre activity. When targeting hepatocytes, hydrodynamic delivery of a Cre-expression plasmid can convert Cre-responsive alleles without inducing the intracellular or systemic antiviral responses often associated with viral-derived Cre-expression vectors. In this method, rapid high-volume intravenous inoculation induces hepatocyte-targeted uptake of extracellular molecules. Here we tested whether hydrodynamic delivery of Cre protein or Cre fused to the HIV-TAT cell-penetrating peptide could convert Cre-responsive reporters in hepatocytes of mice. Hydrodynamic delivery of 2 nmol of either Cre or TAT-Cre protein converted the reporter allele in 5 to 20% of hepatocytes. Neither protein gave detectable Cre activity in endothelia, non-liver organs, or non-hepatocyte cells in liver. Using mice homozygous for a Cre-responsive marker that directs red- (Cre-naïve) or green- (Cre-converted) fluorescent proteins to the nucleus, we assessed sub-saturation Cre-activity. One month after hydrodynamic inoculation with Cre protein, 58% of hepatocyte nuclei that were green were also red, indicating that less than half of the hepatocytes that had obtained enough Cre to convert one marker allele to green were able to convert all alleles. For comparison, one month after hydrodynamic delivery of a Cre-expression plasmid with a weak promoter, only 26% of the green nuclei were also red. Our results show that hydrodynamic delivery of Cre protein allows rapid allelic conversion in hepatocytes, but Cre-activity is sub-saturating so many cells will not convert multiple Cre-responsive alleles. PMID:24626158

  11. Spontaneous chondroma formation in CD2-Cre-driven Erk-deficient mice.

    Science.gov (United States)

    Shiokawa, Moe; Lu, Xiuyuan; Miyake, Yasunobu; Ishikawa, Eri; Pagès, Gilles; Pouysségur, Jacques; Ogata, Masato; Yamasaki, Sho

    2017-12-18

    Lineage-specific Cre Tg mice are widely used to delineate the functions of genes in a tissue-specific manner. Several T-cell-specific promoter cassettes have been developed; however, the activities of those promoters in non-T cells have not been investigated extensively. Here, we report that CD2-Cre-mediated deletion of Erk proteins by generating CD2-Cre × Erk1-/-Erk2flox/flox (Erk∆CD2-Cre) mice results in abnormal cartilage hyperplasia. Histological analysis revealed that this abnormality is caused by aberrant hyperplasia of chondrocytes. The presence of Erk-deficient T cells is not required for this chondroma formation, as it was similarly observed in the absence of T cells in a CD3ε-deficient background. In addition, adoptive transfer of bone marrow cells from Erk∆CD2-Cre mice to wild-type recipients did not cause chondroma formation, suggesting that Erk-deficient non-immune cells are responsible for this abnormality. By tracing Cre-expressed tissues using a ROSA26-STOP-RFP allele, we found that the chondroma emitted RFP fluorescence, indicating that functional Cre is expressed in hyperplastic chondrocytes in Erk∆CD2-Cre mice. Furthermore, RFP+ chondrocytes were also found in an Erk-sufficient background, albeit without aberrant growth. These results suggest that unexpected expression of CD2-driven Cre in chondrocytes generates Erk-deficient chondrocytes, resulting in hyperplastic cartilage formation. Recently, two independent reports showed that CD4-Cre-mediated Ras-Erk signaling ablation led to similar abnormal cartilage formation (Guittard, G., Gallardo, D. L., Li, W. et al. 2017. Unexpected cartilage phenotype in CD4-Cre-conditional SOS-deficient mice. Front. Immunol. 8:343; Wehenkel, M., Corr, M., Guy, C. S. et al. 2017. Extracellular signal-regulated kinase signaling in CD4-expressing cells inhibits osteochondromas. Front. Immunol. 8:482). Together with these reports, our study suggests that an unexpected link exists between T-like cell and

  12. Variation of CRE with exponents of time and number of fractions

    International Nuclear Information System (INIS)

    Supe, S.J.; Rao, S.M.; Sawant, S.G.; Bisht, J.S.

    1976-01-01

    The concept of NSD has been modified into TDF's by Orton and Ellis and CRE's by Kirk et al. It was aimed to study the variability of these new concepts on the exponents of time and number of fractions. It was found that TDF has larger variation with the exponents compared to that of CRE. The use of CRE and NSD for solving the treatment scheduling problems or for intercomparison of various regimes has been simplified by providing readymade estimation of CRE for various doses/fraction with increasing number of fractions. As there is increasing evidence for the change of exponents J and H, nomograms are presented to determine the CRE for various values of J and H. The variation of decay correction factors with the exponent H is also evaluated and is presented. This will help various radiotherapists to use CRE and the decay correction factors consistent with their clinical findings. (orig.) [de

  13. Initial characterization of the Pf-Int recombinase from the malaria parasite Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Mehdi Ghorbal

    Full Text Available Genetic variation is an essential means of evolution and adaptation in many organisms in response to environmental change. Certain DNA alterations can be carried out by site-specific recombinases (SSRs that fall into two families: the serine and the tyrosine recombinases. SSRs are seldom found in eukaryotes. A gene homologous to a tyrosine site-specific recombinase has been identified in the genome of Plasmodium falciparum. The sequence is highly conserved among five other members of Plasmodia.The predicted open reading frame encodes for a ∼57 kDa protein containing a C-terminal domain including the putative tyrosine recombinase conserved active site residues R-H-R-(H/W-Y. The N-terminus has the typical alpha-helical bundle and potentially a mixed alpha-beta domain resembling that of λ-Int. Pf-Int mRNA is expressed differentially during the P. falciparum erythrocytic life stages, peaking in the schizont stage. Recombinant Pf-Int and affinity chromatography of DNA from genomic or synthetic origin were used to identify potential DNA targets after sequencing or micro-array hybridization. Interestingly, the sequences captured also included highly variable subtelomeric genes such as var, rif, and stevor sequences. Electrophoretic mobility shift assays with DNA were carried out to verify Pf-Int/DNA binding. Finally, Pf-Int knock-out parasites were created in order to investigate the biological role of Pf-Int.Our data identify for the first time a malaria parasite gene with structural and functional features of recombinases. Pf-Int may bind to and alter DNA, either in a sequence specific or in a non-specific fashion, and may contribute to programmed or random DNA rearrangements. Pf-Int is the first molecular player identified with a potential role in genome plasticity in this pathogen. Finally, Pf-Int knock-out parasite is viable showing no detectable impact on blood stage development, which is compatible with such function.

  14. Commission for Energy regulation (CRE) - Activity report june 2008

    International Nuclear Information System (INIS)

    2008-01-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2008 activity report of CRE. Content: A - How CRE works: CRE regulatory authority and organisation: Powers, Organisation; Budget resources; Personnel; B - The Standing Committee for Dispute Settlement and Sanctions (CoRDiS) activity: Admissibility, Authority; C - Building a single European energy market: Overview; Organisation and coordination of the main European regulators (Work carried out collectively by European regulators, Regulator organisation and development, CRE's relations with European Community institutions, Development of CEER activities outside the European Union); CRE's European activities (The contribution of European regulators to the Third Energy Package, Integration of gas markets, Integration of electricity markets, Operation of the European interconnected electricity grid and security of supply, Opening up markets to benefit consumers); European Community activities (The European Commission's proposals for the internal energy market: the Third Energy Package, The European Commission's proposals for fighting climate change: the Climate Package, Infringement

  15. Structure of a hexameric form of RadA recombinase from Methanococcus voltae

    International Nuclear Information System (INIS)

    Du, Liqin; Luo, Yu

    2012-01-01

    Hexameric rings of RadA recombinase from M. voltae have been crystallized. Structural comparisons suggest that homologues of RadA tend to form double-ringed assemblies. Archaeal RadA proteins are close homologues of eukaryal Rad51 and DMC1 proteins and are remote homologues of bacterial RecA proteins. For the repair of double-stranded breaks in DNA, these recombinases promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. This DNA-repair function also plays a key role in the resistance of cancer cells to chemotherapy and radiotherapy and in the resistance of bacterial cells to antibiotics. A hexameric form of a truncated Methanococcus voltae RadA protein devoid of its small N-terminal domain has been crystallized. The RadA hexamers further assemble into two-ringed assemblies. Similar assemblies can be observed in the crystals of Pyrococcus furiosus RadA and Homo sapiens DMC1. In all of these two-ringed assemblies the DNA-interacting L1 region of each protomer points inward towards the centre, creating a highly positively charged locus. The electrostatic characteristics of the central channels can be utilized in the design of novel recombinase inhibitors

  16. Commission for Energy regulation (CRE) - Activity report june 2008; Commission de regulation de l'energie (CRE) - Rapport d'activite juin 2008

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2008 activity report of CRE. Content: A - How CRE works: CRE regulatory authority and organisation: Powers, Organisation; Budget resources; Personnel; B - The Standing Committee for Dispute Settlement and Sanctions (CoRDiS) activity: Admissibility, Authority; C - Building a single European energy market: Overview; Organisation and coordination of the main European regulators (Work carried out collectively by European regulators, Regulator organisation and development, CRE's relations with European Community institutions, Development of CEER activities outside the European Union); CRE's European activities (The contribution of European regulators to the Third Energy Package, Integration of gas markets, Integration of electricity markets, Operation of the European interconnected electricity grid and security of supply, Opening up markets to benefit consumers); European Community activities (The European Commission's proposals for the internal energy market: the Third Energy Package, The European Commission's proposals for fighting climate change: the Climate

  17. Commission for Energy regulation (CRE) - Activity report june 2006

    International Nuclear Information System (INIS)

    2006-01-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2006 activity report of CRE. Content: A - Opening of the electricity and natural gas markets to household consumers on 1 July 2007: CRE at the service of eligible customers (Information for eligible customers, Improved knowledge of non-household customers); Monitoring of the non-discrimination, transparency and independence of system operators (Drafting and distribution of codes of good conduct for system operators, The necessary improvement of system operator independence); Preparing the practical methods of opening: GTE 2007 and GTG 2007 (The necessary simplification of relations between operators and customers, Achieving a greater level of consumer information and protection, The clearly defined stages of the 'customer pathway', Profiling and settlement mechanisms: turning experience feedback from 2004 to good account); Persisting uncertainties and hurdles (The need for a suitable regulatory and legislative platform, Hurdles to the opening of the household market); B - Regulation of the natural gas market: The gas market in the European context (Increasing weight of imports in gas

  18. Commission for Energy regulation (CRE) - Activity report june 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2006 activity report of CRE. Content: A - Opening of the electricity and natural gas markets to household consumers on 1 July 2007: CRE at the service of eligible customers (Information for eligible customers, Improved knowledge of non-household customers); Monitoring of the non-discrimination, transparency and independence of system operators (Drafting and distribution of codes of good conduct for system operators, The necessary improvement of system operator independence); Preparing the practical methods of opening: GTE 2007 and GTG 2007 (The necessary simplification of relations between operators and customers, Achieving a greater level of consumer information and protection, The clearly defined stages of the 'customer pathway', Profiling and settlement mechanisms: turning experience feedback from 2004 to good account); Persisting uncertainties and hurdles (The need for a suitable regulatory and legislative platform, Hurdles to the opening of the household market); B - Regulation of the natural gas market: The gas market in the European context (Increasing weight of

  19. Generation and analysis of an improved Foxg1-IRES-Cre driver mouse line.

    Science.gov (United States)

    Kawaguchi, Daichi; Sahara, Setsuko; Zembrzycki, Andreas; O'Leary, Dennis D M

    2016-04-01

    Foxg1 expression is highly restricted to the telencephalon and other head structures in the early embryo. This expression pattern has been exploited to generate conditional knockout mice, based on a widely used Foxg1-Cre knock-in line (Foxg1(tm1(cre)Skm)), in which the Foxg1 coding region was replaced by the Cre gene. The utility of this line, however, is severely hampered for two reasons: (1) Foxg1-Cre mice display ectopic and unpredictable Cre activity, and (2) Foxg1 haploinsufficiency can produce neurodevelopmental phenotypes. To overcome these issues, we have generated a new Foxg1-IRES-Cre knock-in mouse line, in which an IRES-Cre cassette was inserted in the 3'UTR of Foxg1 locus, thus preserving the endogenous Foxg1 coding region and un-translated gene regulatory sequences in the 3'UTR, including recently discovered microRNA target sites. We further demonstrate that the new Foxg1-IRES-Cre line displays consistent Cre activity patterns that recapitulated the endogenous Foxg1 expression at embryonic and postnatal stages without causing defects in cortical development. We conclude that the new Foxg1-IRES-Cre mouse line is a unique and advanced tool for studying genes involved in the development of the telencephalon and other Foxg1-expressing regions starting from early embryonic stages. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Tissue Specific Expression of Cre in Rat Tyrosine Hydroxylase and Dopamine Active Transporter-Positive Neurons.

    Science.gov (United States)

    Liu, Zhenyi; Brown, Andrew; Fisher, Dan; Wu, Yumei; Warren, Joe; Cui, Xiaoxia

    2016-01-01

    The rat is a preferred model system over the mouse for neurological studies, and cell type-specific Cre expression in the rat enables precise ablation of gene function in neurons of interest, which is especially valuable for neurodegenerative disease modeling and optogenetics. Yet, few such Cre rats are available. Here we report the characterization of two Cre rats, tyrosine hydroxylase (TH)-Cre and dopamine active transporter (DAT or Slc6a3)-Cre, by using a combination of immunohistochemistry (IHC) and mRNA fluorescence in situ hybridization (FISH) as well as a fluorescent reporter for Cre activity. We detected Cre expression in expected neurons in both Cre lines. Interestingly, we also found that in Th-Cre rats, but not DAT-Cre rats, Cre is expressed in female germ cells, allowing germline excision of the floxed allele and hence the generation of whole-body knockout rats. In summary, our data demonstrate that targeted integration of Cre cassette lead to faithful recapitulation of expression pattern of the endogenous promoter, and mRNA FISH, in addition to IHC, is an effective method for the analysis of the spatiotemporal gene expression patterns in the rat brain, alleviating the dependence on high quality antibodies that are often not available against rat proteins. The Th-Cre and the DAT-Cre rat lines express Cre in selective subsets of dopaminergic neurons and should be particularly useful for researches on Parkinson's disease.

  1. Corporate branding: an exploration of the influence of CRE

    NARCIS (Netherlands)

    Appel - Meulenbroek, H.A.J.A.; Havermans, D.W.Q.; Janssen, I.I.; Kempen, van A.J.M.

    2010-01-01

    Purpose – The purpose of this paper is to understand how corporate real estate (CRE) can add value to corporate branding and how corporate branding strategies for CRE can be determined. Design/methodology/approach – The paper presents a theoretical background for corporate branding and real estate

  2. Pdgfrb-Cre targets lymphatic endothelial cells of both venous and non-venous origins.

    Science.gov (United States)

    Ulvmar, Maria H; Martinez-Corral, Ines; Stanczuk, Lukas; Mäkinen, Taija

    2016-06-01

    The Pdgfrb-Cre line has been used as a tool to specifically target pericytes and vascular smooth muscle cells. Recent studies showed additional targeting of cardiac and mesenteric lymphatic endothelial cells (LECs) by the Pdgfrb-Cre transgene. In the heart, this was suggested to provide evidence for a previously unknown nonvenous source of LECs originating from yolk sac (YS) hemogenic endothelium (HemEC). Here we show that Pdgfrb-Cre does not, however, target YS HemEC or YS-derived erythro-myeloid progenitors (EMPs). Instead, a high proportion of ECs in embryonic blood vessels of multiple organs, as well as venous-derived LECs were targeted. Assessment of temporal Cre activity using the R26-mTmG double reporter suggested recent occurrence of Pdgfrb-Cre recombination in both blood and lymphatic ECs. It thus cannot be excluded that Pdgfrb-Cre mediated targeting of LECs is due to de novo expression of the Pdgfrb-Cre transgene or their previously established venous endothelial origin. Importantly, Pdgfrb-Cre targeting of LECs does not provide evidence for YS HemEC origin of the lymphatic vasculature. Our results highlight the need for careful interpretation of lineage tracing using constitutive Cre lines that cannot discriminate active from historical expression. The early vascular targeting by the Pdgfrb-Cre also warrants consideration for its use in studies of mural cells. genesis 54:350-358, 2016. © 2016 The Authors. Genesis Published by Wiley Periodicals, Inc. © 2016 The Authors. Genesis Published by Wiley Periodicals, Inc.

  3. Commission for Energy regulation (CRE) - Activity report June 2004

    International Nuclear Information System (INIS)

    2004-01-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2004 activity report of CRE. Content: A - Opening of the gas and electricity markets for professional customers on 1 July 2004; B - Regulation of the gas market: Gas markets and players (The European environment, The French gas market); Regulation of the gas market (Implementing regulation, Works planned for the coming year; C - Regulation of the electricity market: The electricity markets and players (The European electricity markets, The French electricity market, Monitoring the electricity market); Regulation of the French electricity market (Access to public grid, Cross-border exchanges, Un-bundled accounting principles); The public electricity service in the regulated market (Content of the public service, Public service charges, Electricity production public service financing, Electricity sales tariffs) D - The working of CRE: How CRE exercises its jurisdiction, Tools; E - Appendices: Glossary, Units and conversions, Council of European Energy Regulators, Index of tables and figures

  4. Generation of CRISPR/Cas9-mediated bicistronic knock-in ins1-cre driver mice.

    Science.gov (United States)

    Hasegawa, Yoshikazu; Hoshino, Yoshikazu; Ibrahim, Abdelaziz E; Kato, Kanako; Daitoku, Yoko; Tanimoto, Yoko; Ikeda, Yoshihisa; Oishi, Hisashi; Takahashi, Satoru; Yoshiki, Atsushi; Yagami, Ken-Ichi; Iseki, Hiroyoshi; Mizuno, Seiya; Sugiyama, Fumihiro

    2016-07-29

    In the present study, we generated novel cre driver mice for gene manipulation in pancreatic β cells. Using the CRISPR/Cas9 system, stop codon sequences of Ins1 were targeted for insertion of cre, including 2A sequences. A founder of C57BL/6J-Ins1(em1 (cre) Utr) strain was produced from an oocyte injected with pX330 containing the sequences encoding gRNA and Cas9 and a DNA donor plasmid carrying 2A-cre. (R26GRR x C57BL/6J-Ins1(em1 (cre) Utr)) F1 mice were histologically characterized for cre-loxP recombination in the embryonic and adult stages; cre-loxP recombination was observed in all pancreatic islets examined in which almost all insulin-positive cells showed tdsRed fluorescence, suggesting β cell-specific recombination. Furthermore, there were no significant differences in results of glucose tolerance test among genotypes (homo/hetero/wild). Taken together, these observations indicated that C57BL/6J-Ins1(em1 (cre) Utr) is useful for studies of glucose metabolism and the strategy of bicistronic cre knock-in using the CRISPR/Cas9 system could be useful for production of cre driver mice.

  5. Preserved dopaminergic homeostasis and dopamine-related behaviour in hemizygous TH-Cre mice

    DEFF Research Database (Denmark)

    Thomsen, Annika Højrup Runegaard; Jensen, Kathrine L; Fitzpatrick, Ciarán M

    2017-01-01

    assessment of the dopaminergic system in hemizygous tyrosine hydroxylase (TH)-Cre mice in comparison to wild-type (WT) controls. Our data show that TH-Cre mice display preserved dopaminergic homeostasis with unaltered levels of TH and dopamine as well as unaffected dopamine turnover in striatum. TH-Cre mice...

  6. New inducible genetic method reveals critical roles of GABA in the control of feeding and metabolism.

    Science.gov (United States)

    Meng, Fantao; Han, Yong; Srisai, Dollada; Belakhov, Valery; Farias, Monica; Xu, Yong; Palmiter, Richard D; Baasov, Timor; Wu, Qi

    2016-03-29

    Currently available inducible Cre/loxP systems, despite their considerable utility in gene manipulation, have pitfalls in certain scenarios, such as unsatisfactory recombination rates and deleterious effects on physiology and behavior. To overcome these limitations, we designed a new, inducible gene-targeting system by introducing an in-frame nonsense mutation into the coding sequence of Cre recombinase (nsCre). Mutant mRNAs transcribed from nsCre transgene can be efficiently translated into full-length, functional Cre recombinase in the presence of nonsense suppressors such as aminoglycosides. In a proof-of-concept model, GABA signaling from hypothalamic neurons expressing agouti-related peptide (AgRP) was genetically inactivated within 4 d after treatment with a synthetic aminoglycoside. Disruption of GABA synthesis in AgRP neurons in young adult mice led to a dramatic loss of body weight due to reduced food intake and elevated energy expenditure; they also manifested glucose intolerance. In contrast, older mice with genetic inactivation of GABA signaling by AgRP neurons had only transient reduction of feeding and body weight; their energy expenditure and glucose tolerance were unaffected. These results indicate that GABAergic signaling from AgRP neurons plays a key role in the control of feeding and metabolism through an age-dependent mechanism. This new genetic technique will augment current tools used to elucidate mechanisms underlying many physiological and neurological processes.

  7. The Carboxy-Terminal ?N Helix of the Archaeal XerA Tyrosine Recombinase Is a Molecular Switch to Control Site-Specific Recombination

    OpenAIRE

    Serre, Marie-Claude; El Arnaout, Toufic; Brooks, Mark A.; Durand, Dominique; Lisboa, Johnny; Lazar, Noureddine; Raynal, Bertrand; van Tilbeurgh, Herman; Quevillon-Cheruel, Sophie

    2013-01-01

    Tyrosine recombinases are conserved in the three kingdoms of life. Here we present the first crystal structure of a full-length archaeal tyrosine recombinase, XerA from Pyrococcus abyssi, at 3.0 Å resolution. In the absence of DNA substrate XerA crystallizes as a dimer where each monomer displays a tertiary structure similar to that of DNA-bound Tyr-recombinases. Active sites are assembled in the absence of dif except for the catalytic Tyr, which is extruded and located equidistant from each ...

  8. Commission for Energy regulation (CRE) - Activity report June 2004

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2004 activity report of CRE. Content: A - Opening of the gas and electricity markets for professional customers on 1 July 2004; B - Regulation of the gas market: Gas markets and players (The European environment, The French gas market); Regulation of the gas market (Implementing regulation, Works planned for the coming year; C - Regulation of the electricity market: The electricity markets and players (The European electricity markets, The French electricity market, Monitoring the electricity market); Regulation of the French electricity market (Access to public grid, Cross-border exchanges, Un-bundled accounting principles); The public electricity service in the regulated market (Content of the public service, Public service charges, Electricity production public service financing, Electricity sales tariffs) D - The working of CRE: How CRE exercises its jurisdiction, Tools; E - Appendices: Glossary, Units and conversions, Council of European Energy Regulators, Index of tables and figures.

  9. Osteocytes, not Osteoblasts or Lining Cells, are the Main Source of the RANKL Required for Osteoclast Formation in Remodeling Bone.

    Directory of Open Access Journals (Sweden)

    Jinhu Xiong

    Full Text Available The cytokine receptor activator of nuclear factor kappa B ligand (RANKL, encoded by the Tnfsf11 gene, is essential for osteoclastogenesis and previous studies have shown that deletion of the Tnfsf11 gene using a Dmp1-Cre transgene reduces osteoclast formation in cancellous bone by more than 70%. However, the Dmp1-Cre transgene used in those studies leads to recombination in osteocytes, osteoblasts, and lining cells making it unclear whether one or more of these cell types produce the RANKL required for osteoclast formation in cancellous bone. Because osteoblasts, osteocytes, and lining cells have distinct locations and functions, distinguishing which of these cell types are sources of RANKL is essential for understanding the orchestration of bone remodeling. To distinguish between these possibilities, we have now created transgenic mice expressing the Cre recombinase under the control of regulatory elements of the Sost gene, which is expressed in osteocytes but not osteoblasts or lining cells in murine bone. Activity of the Sost-Cre transgene in osteocytes, but not osteoblast or lining cells, was confirmed by crossing Sost-Cre transgenic mice with tdTomato and R26R Cre-reporter mice, which express tdTomato fluorescent protein or LacZ, respectively, only in cells expressing the Cre recombinase or their descendants. Deletion of the Tnfsf11 gene in Sost-Cre mice led to a threefold decrease in osteoclast number in cancellous bone and increased cancellous bone mass, mimicking the skeletal phenotype of mice in which the Tnfsf11 gene was deleted using the Dmp1-Cre transgene. These results demonstrate that osteocytes, not osteoblasts or lining cells, are the main source of the RANKL required for osteoclast formation in remodeling cancellous bone.

  10. Rapid Increase in Prevalence of Carbapenem-Resistant Enterobacteriaceae (CRE) and Emergence of Colistin Resistance Gene mcr-1 in CRE in a Hospital in Henan, China.

    Science.gov (United States)

    Li, Yi; Sun, Qiao-Ling; Shen, Yingbo; Zhang, Yangjunna; Yang, Jun-Wen; Shu, Ling-Bin; Zhou, Hong-Wei; Wang, Yang; Wang, Bing; Zhang, Rong; Wang, Shaolin; Shen, Zhangqi

    2018-04-01

    The global spread of carbapenem-resistant Enterobacteriaceae (CRE) is one of the most severe threats to human health in a clinical setting. The recent emergence of plasmid-mediated colistin resistance gene mcr-1 among CRE strains greatly compromises the use of colistin as a last resort for the treatment of infections caused by CRE. This study aimed to understand the current epidemiological trends and characteristics of CRE from a large hospital in Henan, the most populous province in China. From 2014 to 2016, a total of 7,249 Enterobacteriaceae isolates were collected from clinical samples, among which 18.1% (1,311/7,249) were carbapenem resistant. Carbapenem-resistant Klebsiella pneumoniae and carbapenem-resistant Escherichia coli were the two most common CRE species, with Klebsiella pneumoniae carbapenemases (KPC) and New Delhi metallo-β-lactamases (NDM), respectively, responsible for the carbapenem resistance of the two species. Notably, >57.0% ( n = 589) of the K. pneumoniae isolates from the intensive care unit were carbapenem resistant. Furthermore, bla NDM-5 and mcr-1 were found to coexist in one E. coli isolate, which exhibited resistance to almost all tested antibiotics. Overall, we observed a significant increase in the prevalence of CRE isolates during the study period and suggest that carbapenems may no longer be considered to be an effective treatment for infections caused by K. pneumoniae in the studied hospital. Copyright © 2018 American Society for Microbiology.

  11. CGRPα within the Trpv1-Cre population contributes to visceral nociception.

    Science.gov (United States)

    Spencer, Nick J; Magnúsdóttir, Elín I; Jakobsson, Jon E T; Kestell, Garreth; Chen, Bao Nan; Morris, David; Brookes, Simon J; Lagerström, Malin C

    2018-02-01

    The role of calcitonin gene-related peptide (CGRP) in visceral and somatic nociception is incompletely understood. CGRPα is highly expressed in sensory neurons of dorsal root ganglia and particularly in neurons that also express the transient receptor potential cation channel subfamily V member 1 (Trpv1). Therefore, we investigated changes in visceral and somatic nociception following deletion of CGRPα from the Trpv1-Cre population using the Cre/lox system. In control mice, acetic acid injection (0.6%, ip) caused significant immobility (time stationary), an established indicator of visceral pain. In CGRPα-mCherry lx/lx ;Trpv1-Cre mice, the duration of immobility was significantly less than controls, and the distance CGRPα-mCherry lx/lx ;Trpv1-Cre mice traveled over 20 min following acetic acid was significantly greater than controls. However, following acetic acid injection, there was no difference between genotypes in the writhing reflex, number of abdominal licks, or forepaw wipes of the cheek. CGRPα-mCherry lx/lx ;Trpv1-Cre mice developed more pronounced inflammation-induced heat hypersensitivity above baseline values compared with controls. However, analyses of noxious acute heat or cold transmission revealed no difference between genotypes. Also, odor avoidance test, odor preference test, and buried food test for olfaction revealed no differences between genotypes. Our findings suggest that CGRPα-mediated transmission within the Trpv1-Cre population plays a significant role in visceral nociceptive pathways underlying voluntary movement. Monitoring changes in movement over time is a sensitive parameter to identify differences in visceral nociception, compared with writhing reflexes, abdominal licks, or forepaw wipes of the cheek that were unaffected by deletion of CGRPα- from Trpv1-Cre population and likely utilize different mechanisms. NEW & NOTEWORTHY The neuropeptide calcitonin gene-related peptide (CGRP) is highly colocalized with transient receptor

  12. Teh CRE system applied to continuous irradiation. A Physician's view. Chapter 30

    International Nuclear Information System (INIS)

    Watson, E.R.

    1980-01-01

    The CRE system, used in radiotherapy, is an attempt at a simple, empirical model predicting the response of tissue to irradiation. The two basic formulae used in the CRE system are given followed by a consideration of a number of variable factors which may influence the CRE values. The Cathetron afterloading radiotherapy device demands a completely different schedule from those to which the CRE system is normally applied. The problem of converting a continuous intracavitary schedule to one of fractionated intracavitary treatment for the Cathetron is considered particularly in relation to the volume effect of continuous radiation and also to the wide variation of dose across the volume. It is concluded that in the present state of knowledge it would be unwise to make confident predictions of Cathetron doses on the basis of empirical descriptions such as the CRE. (U.K.)

  13. Usability as the Key Factor to the Design of a Web Server for the CReF Protein Structure Predictor: The wCReF

    Directory of Open Access Journals (Sweden)

    Vanessa Stangherlin Machado Paixão-Cortes

    2018-01-01

    Full Text Available Protein structure prediction servers use various computational methods to predict the three-dimensional structure of proteins from their amino acid sequence. Predicted models are used to infer protein function and guide experimental efforts. This can contribute to solving the problem of predicting tertiary protein structures, one of the main unsolved problems in bioinformatics. The challenge is to understand the relationship between the amino acid sequence of a protein and its three-dimensional structure, which is related to the function of these macromolecules. This article is an extended version of the article wCReF: The Web Server for the Central Residue Fragment-based Method (CReF Protein Structure Predictor, published in the 14th International Conference on Information Technology: New Generations. In the first version, we presented the wCReF, a protein structure prediction server for the central residue fragment-based method. The wCReF interface was developed with a focus on usability and user interaction. With this tool, users can enter the amino acid sequence of their target protein and obtain its approximate 3D structure without the need to install all the multitude of necessary tools. In this extended version, we present the design process of the prediction server in detail, which includes: (A identification of user needs: aiming at understanding the features of a protein structure prediction server, the end user profiles and the commonly-performed tasks; (B server usability inspection: in order to define wCReF’s requirements and features, we have used heuristic evaluation guided by experts in both the human-computer interaction and bioinformatics domain areas, applied to the protein structure prediction servers I-TASSER, QUARK and Robetta; as a result, changes were found in all heuristics resulting in 89 usability problems; (C software requirements document and prototype: assessment results guiding the key features that wCReF must

  14. A Study of Plazomicin Compared With Colistin in Patients With Infection Due to Carbapenem-Resistant Enterobacteriaceae (CRE)

    Science.gov (United States)

    2016-10-03

    Bloodstream Infections (BSI) Due to CRE; Hospital-Acquired Bacterial Pneumonia (HABP) Due to CRE; Ventilator-Associated Bacterial Pneumonia (VABP) Due to CRE; Complicated Urinary Tract Infection (cUTI) Due to CRE; Acute Pyelonephritis (AP) Due to CRE

  15. Tamoxifen-Containing Eye Drops Successfully Trigger Cre-Mediated Recombination in the Entire Eye.

    Science.gov (United States)

    Schlecht, Anja; Leimbeck, Sarah V; Tamm, Ernst R; Braunger, Barbara M

    2016-01-01

    Embryonic lethality in mice with targeted gene deletion is a major issue that can be circumvented by using Cre-loxP-based animal models. Various inducible Cre systems are available, e.g. such that are activated following tamoxifen treatment, and allow deletion of a specific target gene at any desired time point during the life span of the animal. In this study, we describe the efficiency of topical tamoxifen administration by eye drops using a Cre- reporter mouse strain (R26R). We report that tamoxifen-responsive CAGGCre-ER (TM) mice show a robust Cre- mediated recombination throughout the entire eye.

  16. Targeted knock-in of CreER T2 in zebrafish using CRISPR/Cas9.

    Science.gov (United States)

    Kesavan, Gokul; Hammer, Juliane; Hans, Stefan; Brand, Michael

    2018-04-01

    New genome-editing approaches, such as the CRISPR/Cas system, have opened up great opportunities to insert or delete genes at targeted loci and have revolutionized genetics in model organisms like the zebrafish. The Cre-loxp recombination system is widely used to activate or inactivate genes with high spatial and temporal specificity. Using a CRISPR/Cas9-mediated knock-in strategy, we inserted a zebrafish codon-optimized CreER T2 transgene at the otx2 gene locus to generate a conditional Cre-driver line. We chose otx2 as it is a patterning gene of the anterior neural plate that is expressed during early development. By knocking in CreER T2 upstream of the endogenous ATG of otx2, we utilized this gene's native promoter and enhancer elements to perfectly match CreER T2 and endogenous otx2 expression patterns. Next, by combining this novel driver line with a Cre-dependent reporter line, we show that only in the presence of tamoxifen can efficient Cre-loxp-mediated recombination be achieved in the anterior neural plate-derived tissues like the telencephalon, the eye and the optic tectum. Our results imply that the otx2:CreER T2 transgenic fish will be a valuable tool for lineage tracing and conditional mutant studies in larval and adult zebrafish.

  17. Site-specific DNA Inversion by Serine Recombinases

    Science.gov (United States)

    2015-01-01

    Reversible site-specific DNA inversion reactions are widely distributed in bacteria and their viruses. They control a range of biological reactions that most often involve alterations of molecules on the surface of cells or phage. These programmed DNA rearrangements usually occur at a low frequency, thereby preadapting a small subset of the population to a change in environmental conditions, or in the case of phages, an expanded host range. A dedicated recombinase, sometimes with the aid of additional regulatory or DNA architectural proteins, catalyzes the inversion of DNA. RecA or other components of the general recombination-repair machinery are not involved. This chapter discusses site-specific DNA inversion reactions mediated by the serine recombinase family of enzymes and focuses on the extensively studied serine DNA invertases that are stringently controlled by the Fis-bound enhancer regulatory system. The first section summarizes biological features and general properties of inversion reactions by the Fis/enhancer-dependent serine invertases and the recently described serine DNA invertases in Bacteroides. Mechanistic studies of reactions catalyzed by the Hin and Gin invertases are then discussed in more depth, particularly with regards to recent advances in our understanding of the function of the Fis/enhancer regulatory system, the assembly of the active recombination complex (invertasome) containing the Fis/enhancer, and the process of DNA strand exchange by rotation of synapsed subunit pairs within the invertasome. The role of DNA topological forces that function in concert with the Fis/enhancer controlling element in specifying the overwhelming bias for DNA inversion over deletion and intermolecular recombination is emphasized. PMID:25844275

  18. A Nestin-cre transgenic mouse is insufficient for recombination in early embryonic neural progenitors

    Directory of Open Access Journals (Sweden)

    Huixuan Liang

    2012-09-01

    Nestin-cre transgenic mice have been widely used to direct recombination to neural stem cells (NSCs and intermediate neural progenitor cells (NPCs. Here we report that a readily utilized, and the only commercially available, Nestin-cre line is insufficient for directing recombination in early embryonic NSCs and NPCs. Analysis of recombination efficiency in multiple cre-dependent reporters and a genetic mosaic line revealed consistent temporal and spatial patterns of recombination in NSCs and NPCs. For comparison we utilized a knock-in Emx1cre line and found robust recombination in NSCs and NPCs in ventricular and subventricular zones of the cerebral cortices as early as embryonic day 12.5. In addition we found that the rate of Nestin-cre driven recombination only reaches sufficiently high levels in NSCs and NPCs during late embryonic and early postnatal periods. These findings are important when commercially available cre lines are considered for directing recombination to embryonic NSCs and NPCs.

  19. Commission for Energy regulation (CRE) - Activity report June 2005; Commission de regulation de l'energie (CRE) - Rapport d'activite juin 2005

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2005 activity report of CRE. Content: A - The opening of the markets in France and in Europe: The opening of the markets one year after 1 July 2004 (An especially important step, Electricity and gas: a common framework with structural differences, The coexistence of market prices and regulated tariffs); The European texts of 26 June 2003 (Texts to give new impetus, Texts to harmonize the role and powers of national regulators, Texts to guarantee the independence of system operators, Texts to ensure transparent and non-discriminatory access to networks, Texts providing for strengthening of interconnections); The outlook for 2007, a fully open market (1 July 2007: a date set by the directives, Priority given to informing and protecting consumers); B - Regulation of the natural gas market: The gas market in the European context (Europe's dependency on imports is increasing, Gas prices increased considerably across the whole of Europe in 2004, The European gas scene continues to be dominated by a small number of players, Gas infrastructures need to be developed in Europe, The new European

  20. Efficient delivery of genome-editing proteins using bioreducible lipid nanoparticles

    Science.gov (United States)

    A central challenge to the development of protein-based therapeutics is the inefficiency of delivery of protein cargo across the mammalian cell membrane, including escape from endosomes. Here we report that combining bioreducible lipid nanoparticles with negatively supercharged Cre recombinase or an...

  1. Temporally-controlled site-specific recombination in zebrafish.

    Directory of Open Access Journals (Sweden)

    Stefan Hans

    Full Text Available Conventional use of the site-specific recombinase Cre is a powerful technology in mouse, but almost absent in other vertebrate model organisms. In zebrafish, Cre-mediated recombination efficiency was previously very low. Here we show that using transposon-mediated transgenesis, Cre is in fact highly efficient in this organism. Furthermore, temporal control of recombination can be achieved by using the ligand-inducible CreER(T2. Site-specific recombination only occurs upon administration of the drug tamoxifen (TAM or its active metabolite, 4-hydroxy-tamoxifen (4-OHT. Cre-mediated recombination is detectable already 4 or 2 hours after administration of TAM or 4-OHT, demonstrating fast recombination kinetics. In addition, low doses of TAM allow mosaic labeling of single cells. Combined, our results show that conditional Cre/lox will be a valuable tool for both, embryonic and adult zebrafish studies. Furthermore, single copy insertion transgenesis of Cre/lox constructs suggest a strategy suitable also for other organisms.

  2. Potential economic burden of carbapenem-resistant Enterobacteriaceae (CRE) in the United States.

    Science.gov (United States)

    Bartsch, S M; McKinnell, J A; Mueller, L E; Miller, L G; Gohil, S K; Huang, S S; Lee, B Y

    2017-01-01

    The Centers for Disease Control and Prevention considers carbapenem-resistant Enterobacteriaceae (CRE) an urgent public health threat; however, its economic burden is unknown. We developed a CRE clinical and economics outcomes model to determine the cost of CRE infection from the hospital, third-party payer, and societal, perspectives and to evaluate the health and economic burden of CRE to the USA. Depending on the infection type, the median cost of a single CRE infection can range from $22 484 to $66 031 for hospitals, $10 440 to $31 621 for third-party payers, and $37 778 to $83 512 for society. An infection incidence of 2.93 per 100 000 population in the USA (9418 infections) would cost hospitals $275 million (95% CR $217-334 million), third-party payers $147 million (95% CR $129-172 million), and society $553 million (95% CR $303-1593 million) with a 25% attributable mortality, and would result in the loss of 8841 (95% CR 5805-12 420) quality-adjusted life years. An incidence of 15 per 100 000 (48 213 infections) would cost hospitals $1.4 billion (95% CR $1.1-1.7 billion), third-party payers $0.8 billion (95% CR $0.6-0.8 billion), and society $2.8 billion (95% CR $1.6-8.2 billion), and result in the loss of 45 261 quality-adjusted life years. The cost of CRE is higher than the annual cost of many chronic diseases and of many acute diseases. Costs rise proportionally with the incidence of CRE, increasing by 2.0 times, 3.4 times, and 5.1 times for incidence rates of 6, 10, and 15 per 100 000 persons. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  3. BIOCHEMICAL AND PHYLOGENETIC STUDIES OF CreD OF Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Muhammad Tausif Chaudhry

    2015-06-01

    Full Text Available CreD characterized as Mg2+-dependent phosphohydrolase with conserved HD domain was involved in 4-cresol metabolism in Corynebacterium glutamicum. Native molecular mass of 54 kDa suggested that the biological unit is a dimer. No deoxynucleotide triphosphate triphosphohydrolase (dNTPase activity was detected for CreD. The apparent Km and Vmax values for 4-nitrophenyl phosphate were 0.35 mM and 16.23 M min-1 mg-1, respectively, while calculated values for kcat and kcat/Km were 0.4 s-1 and 1.14103 M-1 s-1, respectively. Among thiol group inhibitors, iodoacetic acid significantly inhibited phosphohydrolase activity. Sequence identity and phylogenetic analysis suggested universal existence of CreD homologues. Involvement of HD-domain hydrolase in aromatic degradation has not been reported before.

  4. A Novel Dual-cre Motif Enables Two-Way Autoregulation of CcpA in Clostridium acetobutylicum.

    Science.gov (United States)

    Zhang, Lu; Liu, Yanqiang; Yang, Yunpeng; Jiang, Weihong; Gu, Yang

    2018-04-15

    The master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to a cis -acting catabolite-responsive element ( cre ), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual- cre motif that is employed by the CcpA in Clostridium acetobutylicum , a typical solventogenic Clostridium species, for autoregulation. Two cre sites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual- cre motif, cre P , in the promoter region, positively regulates ccpA transcription, whereas cre ORF , in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA bound cre P more strongly than cre ORF in vitro , the in vivo assay showed that cre ORF -based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation of cre ORF was made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA in C. acetobutylicum and, moreover, contributes a new engineering strategy for this industrial strain. IMPORTANCE CcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual- cre motif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular

  5. Physiological characterisation of recombinant Aspergillus nidulans strains with different creA genotypes expressing A-oryzae alpha-amylase

    DEFF Research Database (Denmark)

    Agger, Teit; Petersen, J.B.; O'Connor, S.M.

    2002-01-01

    The physiology of three strains of Aspergillus nidulans was examined-a creA deletion strain, a wild type creA genotype and a strain containing extra copies of the creA gene, all producing Aspergillus oryzae alpha-amylase. The strains were cultured in batch and continuous cultivations and the biom......The physiology of three strains of Aspergillus nidulans was examined-a creA deletion strain, a wild type creA genotype and a strain containing extra copies of the creA gene, all producing Aspergillus oryzae alpha-amylase. The strains were cultured in batch and continuous cultivations...... and the biomass formation and alpha-amylase production was characterised. Overexpression of the creA gene resulted in a lower maximum specific growth rate and a slightly higher repression of the alpha-amylase production during conditions with high glucose concentration. No expression of creA also resulted...... in a decreased maximum specific growth rate, but also in drastic changes in morphology. Furthermore, the expression of alpha-amylase was completely derepressed and creA thus seems to be the only regulatory protein responsible for glucose repression of alpha-amylase expression. The effect of different carbon...

  6. Activation of hypothalamic RIP-Cre neurons promotes beiging of WAT via sympathetic nervous system.

    Science.gov (United States)

    Wang, Baile; Li, Ang; Li, Xiaomu; Ho, Philip Wl; Wu, Donghai; Wang, Xiaoqi; Liu, Zhuohao; Wu, Kelvin Kl; Yau, Sonata Sy; Xu, Aimin; Cheng, Kenneth Ky

    2018-04-01

    Activation of brown adipose tissue (BAT) and beige fat by cold increases energy expenditure. Although their activation is known to be differentially regulated in part by hypothalamus, the underlying neural pathways and populations remain poorly characterized. Here, we show that activation of rat-insulin-promoter-Cre (RIP-Cre) neurons in ventromedial hypothalamus (VMH) preferentially promotes recruitment of beige fat via a selective control of sympathetic nervous system (SNS) outflow to subcutaneous white adipose tissue (sWAT), but has no effect on BAT Genetic ablation of APPL2 in RIP-Cre neurons diminishes beiging in sWAT without affecting BAT, leading to cold intolerance and obesity in mice. Such defects are reversed by activation of RIP-Cre neurons, inactivation of VMH AMPK, or treatment with a β3-adrenergic receptor agonist. Hypothalamic APPL2 enhances neuronal activation in VMH RIP-Cre neurons and raphe pallidus, thereby eliciting SNS outflow to sWAT and subsequent beiging. These data suggest that beige fat can be selectively activated by VMH RIP-Cre neurons, in which the APPL2-AMPK signaling axis is crucial for this defending mechanism to cold and obesity. © 2018 The Authors.

  7. Screening strategy to generate cell specific recombination: a case report with the RIP-Cre mice.

    Science.gov (United States)

    Spinelli, Valeria; Martin, Céline; Dorchies, Emilie; Vallez, Emmanuelle; Dehondt, Hélène; Trabelsi, Mohamed-Sami; Tailleux, Anne; Caron, Sandrine; Staels, Bart

    2015-10-01

    Conditional gene knockout technology is a powerful tool to study the function of a gene in a specific tissue, organ or cell lineage. The most commonly used procedure applies the Cre-LoxP strategy, where the choice of the Cre driver promoter is critical to determine the efficiency and specificity of the system. However, a considered choice of an appropriate promoter does not always protect against the risk of unwanted recombination and the consequent deletion of the gene in other tissues than the desired one(s), due to phenomena of non-specific activation of the Cre transgene. Furthermore, the causes of these phenomena are not completely understood and this can potentially affect every strain of Cre-mice. In our study on the deletion of a same gene in two different tissues, we show that the incidence rate of non-specific recombination in unwanted tissues depends on the Cre driver strain, ranging from 100%, rendering it useless (aP2-Cre strain), to ~5%, which is still compatible with their use (RIP-Cre strain). The use of a simple PCR strategy conceived to detect this occurrence is indispensable when producing a tissue-specific knockout mouse. Therefore, when choosing the Cre-driver promoter, researchers not only have to be careful about its tissue-specificity and timing of activation, but should also include a systematical screening in order to exclude mice in which atypical recombination has occurred and to limit the unnecessary use of laboratory animals in uninterpretable experiments.

  8. Commission for Energy regulation (CRE) - Activity report June 2005

    International Nuclear Information System (INIS)

    2005-01-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2005 activity report of CRE. Content: A - The opening of the markets in France and in Europe: The opening of the markets one year after 1 July 2004 (An especially important step, Electricity and gas: a common framework with structural differences, The coexistence of market prices and regulated tariffs); The European texts of 26 June 2003 (Texts to give new impetus, Texts to harmonize the role and powers of national regulators, Texts to guarantee the independence of system operators, Texts to ensure transparent and non-discriminatory access to networks, Texts providing for strengthening of interconnections); The outlook for 2007, a fully open market (1 July 2007: a date set by the directives, Priority given to informing and protecting consumers); B - Regulation of the natural gas market: The gas market in the European context (Europe's dependency on imports is increasing, Gas prices increased considerably across the whole of Europe in 2004, The European gas scene continues to be dominated by a small number of players, Gas infrastructures need to be developed in Europe, The new European

  9. High-fidelity Glucagon-CreER mouse line generated by CRISPR-Cas9 assisted gene targeting

    Directory of Open Access Journals (Sweden)

    Amanda M. Ackermann

    2017-03-01

    Full Text Available Objective: α-cells are the second most prominent cell type in pancreatic islets and are responsible for producing glucagon to increase plasma glucose levels in times of fasting. α-cell dysfunction and inappropriate glucagon secretion occur in both type 1 and type 2 diabetes. Thus, there is growing interest in studying both normal function and pathophysiology of α-cells. However, tools to target gene ablation or activation specifically of α-cells have been limited, compared to those available for β-cells. Previous Glucagon-Cre and Glucagon-CreER transgenic mouse lines have suffered from transgene silencing, and the only available Glucagon-CreER “knock-in” mouse line results in glucagon haploinsufficiency, which can confound the interpretation of gene deletion analyses. Therefore, we sought to develop a Glucagon-CreERT2 mouse line that would maintain normal glucagon expression and would be less susceptible to transgene silencing. Methods: We utilized CRISPR-Cas9 technology to insert an IRES-CreERT2 sequence into the 3′ UTR of the Glucagon (Gcg locus in mouse embryonic stem cells (ESCs. Targeted ESC clones were then injected into mouse blastocysts to obtain Gcg-CreERT2 mice. Recombination efficiency in GCG+ pancreatic α-cells and glucagon-like peptide 1 positive (GLP1+ enteroendocrine L-cells was measured in Gcg-CreERT2;Rosa26-LSL-YFP mice injected with tamoxifen during fetal development and adulthood. Results: Tamoxifen injection of Gcg-CreERT2;Rosa26-LSL-YFP mice induced high recombination efficiency of the Rosa26-LSL-YFP locus in perinatal and adult α-cells (88% and 95%, respectively, as well as in first-wave fetal α-cells (36% and adult enteroendocrine L-cells (33%. Mice homozygous for the Gcg-CreERT2 allele were phenotypically normal. Conclusions: We successfully derived a Gcg-CreERT2 mouse line that expresses CreERT2 in pancreatic α-cells and enteroendocrine L-cells without disrupting preproglucagon gene expression. These mice

  10. Silencing inhibits Cre-mediated recombination of the Z/AP and Z/EG reporters in adult cells.

    Directory of Open Access Journals (Sweden)

    Michael A Long

    Full Text Available BACKGROUND: The Cre-loxP system has been used to enable tissue specific activation, inactivation and mutation of many genes in vivo and has thereby greatly facilitated the genetic dissection of several cellular and developmental processes. In such studies, Cre-reporter strains, which carry a Cre-activated marker gene, are frequently utilized to validate the expression profile of Cre transgenes, to act as a surrogate marker for excision of a second allele, and to irreversibly label cells for lineage tracing experiments. PRINCIPAL FINDINGS: We have studied three commonly used Cre-reporter strains, Z/AP, Z/EG and R26R-EYFP and have demonstrated that although each reporter can be reliably activated by Cre during early development, exposure to Cre in adult hematopoietic cells results in a much lower frequency of marker-positive cells in the Z/AP or Z/EG strains than in the R26R-EYFP strain. In marker negative cells derived from the Z/AP and Z/EG strains, the transgenic promoter is methylated and Cre-mediated recombination of the locus is inhibited. CONCLUSIONS: These results show that the efficiency of Cre-mediated recombination is not only dependent on the genomic context of a given loxP-flanked sequence, but also on stochastic epigenetic mechanisms underlying transgene variegation. Furthermore, our data highlights the potential shortcomings of utilizing the Z/AP and Z/EG reporters as surrogate markers of excision or in lineage tracing experiments.

  11. Silencing inhibits Cre-mediated recombination of the Z/AP and Z/EG reporters in adult cells.

    Science.gov (United States)

    Long, Michael A; Rossi, Fabio M V

    2009-01-01

    The Cre-loxP system has been used to enable tissue specific activation, inactivation and mutation of many genes in vivo and has thereby greatly facilitated the genetic dissection of several cellular and developmental processes. In such studies, Cre-reporter strains, which carry a Cre-activated marker gene, are frequently utilized to validate the expression profile of Cre transgenes, to act as a surrogate marker for excision of a second allele, and to irreversibly label cells for lineage tracing experiments. We have studied three commonly used Cre-reporter strains, Z/AP, Z/EG and R26R-EYFP and have demonstrated that although each reporter can be reliably activated by Cre during early development, exposure to Cre in adult hematopoietic cells results in a much lower frequency of marker-positive cells in the Z/AP or Z/EG strains than in the R26R-EYFP strain. In marker negative cells derived from the Z/AP and Z/EG strains, the transgenic promoter is methylated and Cre-mediated recombination of the locus is inhibited. These results show that the efficiency of Cre-mediated recombination is not only dependent on the genomic context of a given loxP-flanked sequence, but also on stochastic epigenetic mechanisms underlying transgene variegation. Furthermore, our data highlights the potential shortcomings of utilizing the Z/AP and Z/EG reporters as surrogate markers of excision or in lineage tracing experiments.

  12. Model - SEO - serious ovarian cancer | Center for Cancer Research

    Science.gov (United States)

    Genetically engineered mouse model Developed in house Genetic aberrations: Inactivation of Rb tumor suppression (via K18-T121 transgene) Tp53 loss or mutation (R172H) Brca1 or Brca2 loss Induction by injection of adenovirus expressing Cre recombinase under the ovrian bursa Pathology:

  13. Spinal Hb9::Cre-derived excitatory interneurons contribute to rhythm generation in the mouse.

    Science.gov (United States)

    Caldeira, Vanessa; Dougherty, Kimberly J; Borgius, Lotta; Kiehn, Ole

    2017-01-27

    Rhythm generating neurons are thought to be ipsilaterally-projecting excitatory neurons in the thoracolumbar mammalian spinal cord. Recently, a subset of Shox2 interneurons (Shox2 non-V2a INs) was found to fulfill these criteria and make up a fraction of the rhythm-generating population. Here we use Hb9::Cre mice to genetically manipulate Hb9::Cre-derived excitatory interneurons (INs) in order to determine the role of these INs in rhythm generation. We demonstrate that this line captures a consistent population of spinal INs which is mixed with respect to neurotransmitter phenotype and progenitor domain, but does not overlap with the Shox2 non-V2a population. We also show that Hb9::Cre-derived INs include the comparatively small medial population of INs which continues to express Hb9 postnatally. When excitatory neurotransmission is selectively blocked by deleting Vglut2 from Hb9::Cre-derived INs, there is no difference in left-right and/or flexor-extensor phasing between these cords and controls, suggesting that excitatory Hb9::Cre-derived INs do not affect pattern generation. In contrast, the frequencies of locomotor activity are significantly lower in cords from Hb9::Cre-Vglut2 Δ/Δ mice than in cords from controls. Collectively, our findings indicate that excitatory Hb9::Cre-derived INs constitute a distinct population of neurons that participates in the rhythm generating kernel for spinal locomotion.

  14. Anatomical characterization of cre driver mice for neural circuit mapping and manipulation

    Directory of Open Access Journals (Sweden)

    Julie Ann Harris

    2014-07-01

    Full Text Available Significant advances in circuit-level analyses of the brain require tools that allow for labeling, modulation of gene expression, and monitoring and manipulation of cellular activity in specific cell types and/or anatomical regions. Large-scale projects and individual laboratories have produced hundreds of gene-specific promoter-driven Cre mouse lines invaluable for enabling genetic access to subpopulations of cells in the brain. However, the potential utility of each line may not be fully realized without systematic whole brain characterization of transgene expression patterns. We established a high-throughput in situ hybridization, imaging and data processing pipeline to describe whole brain gene expression patterns in Cre driver mice. Currently, anatomical data from over 100 Cre driver lines are publicly available via the Allen Institute’s Transgenic Characterization database, which can be used to assist researchers in choosing the appropriate Cre drivers for functional, molecular, or connectional studies of different regions and/or cell types in the brain.

  15. Anatomical characterization of Cre driver mice for neural circuit mapping and manipulation

    Science.gov (United States)

    Harris, Julie A.; Hirokawa, Karla E.; Sorensen, Staci A.; Gu, Hong; Mills, Maya; Ng, Lydia L.; Bohn, Phillip; Mortrud, Marty; Ouellette, Benjamin; Kidney, Jolene; Smith, Kimberly A.; Dang, Chinh; Sunkin, Susan; Bernard, Amy; Oh, Seung Wook; Madisen, Linda; Zeng, Hongkui

    2014-01-01

    Significant advances in circuit-level analyses of the brain require tools that allow for labeling, modulation of gene expression, and monitoring and manipulation of cellular activity in specific cell types and/or anatomical regions. Large-scale projects and individual laboratories have produced hundreds of gene-specific promoter-driven Cre mouse lines invaluable for enabling genetic access to subpopulations of cells in the brain. However, the potential utility of each line may not be fully realized without systematic whole brain characterization of transgene expression patterns. We established a high-throughput in situ hybridization (ISH), imaging and data processing pipeline to describe whole brain gene expression patterns in Cre driver mice. Currently, anatomical data from over 100 Cre driver lines are publicly available via the Allen Institute's Transgenic Characterization database, which can be used to assist researchers in choosing the appropriate Cre drivers for functional, molecular, or connectional studies of different regions and/or cell types in the brain. PMID:25071457

  16. CRE communication on the work of the GTE 2007 and GTG 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-09-15

    The work conducted in the first half of 2006 by the Electricity Working Group (GTE) and Gas Working Group (GTG) consultation bodies set up by the Commission de regulation de l'energie (CRE), has specified the practical conditions for market operation defined in CRE communication of 10 January 2006. The CRE decision of 26 May 2005, has led to the creation of a consumer committee within the GTE and GTG allowing the expectations of gas and electricity consumers to be given greater consideration. During the first half of 2006, this consumer committee defined consumers needs in terms of information and protection, and set recommendations, whose application is one of the priorities over the coming months. The consumer committee has become a plenary committee for gas and electricity consumers, with the same stature as the GTE and GTG plenary committees. Following a round table with the players on 14 September 2006, CRE presents the decisions made and guidelines adopted for the coming months in this communication. (author)

  17. CRE communication on the work of the GTE 2007 and GTG 2007

    International Nuclear Information System (INIS)

    2006-09-01

    The work conducted in the first half of 2006 by the Electricity Working Group (GTE) and Gas Working Group (GTG) consultation bodies set up by the Commission de regulation de l'energie (CRE), has specified the practical conditions for market operation defined in CRE communication of 10 January 2006. The CRE decision of 26 May 2005, has led to the creation of a consumer committee within the GTE and GTG allowing the expectations of gas and electricity consumers to be given greater consideration. During the first half of 2006, this consumer committee defined consumers needs in terms of information and protection, and set recommendations, whose application is one of the priorities over the coming months. The consumer committee has become a plenary committee for gas and electricity consumers, with the same stature as the GTE and GTG plenary committees. Following a round table with the players on 14 September 2006, CRE presents the decisions made and guidelines adopted for the coming months in this communication. (author)

  18. Prolactin receptors in Rip-cre cells, but not in AgRP neurones, are involved in energy homeostasis.

    Science.gov (United States)

    Ladyman, S R; MacLeod, M A; Khant Aung, Z; Knowles, P; Phillipps, H R; Brown, R S E; Grattan, D R

    2017-10-01

    Among its many functions, prolactin has been implicated in energy homeostasis, particularly during pregnancy and lactation. The arcuate nucleus is a key site in the regulation of energy balance. The present study aimed to examine whether arcuate nucleus neuronal populations involved in energy homeostasis are prolactin responsive and whether they can mediate the effects of prolactin on energy homeostasis. To determine whether Agrp neurones or Rip-Cre neurones are prolactin responsive, transgenic mice expressing the reporter td-tomato in Agrp neurones (td-tomato/Agrp-Cre) or Rip-Cre neurones (td-tomato/Rip-Cre) were treated with prolactin and perfused 45 minutes later. Brains were processed for double-labelled immunohistochemistry for pSTAT5, a marker of prolactin-induced intracellular signalling, and td-tomato. In addition, Agrp-Cre mice and Rip-Cre mice were crossed with mice in which the prolactin receptor gene (Prlr) was flanked with LoxP sites (Prlr lox/lox mice). The Prlr lox/lox construct was designed such that Cre-mediated recombination resulted in deletion of the Prlr and expression of green fluorescent protein (GFP) in its place. In td-tomato/Rip-Cre mice, prolactin-induced pSTAT5 was co-localised with td-tomato, indicating that there is a subpopulation of Rip-Cre neurones in the arcuate nucleus that respond to prolactin. Furthermore, mice with a specific deletion of Prlr in Rip-Cre neurones had lower body weights, increased oxygen consumption, increased running wheel activity and numerous cells in the arcuate nucleus had positive GFP staining indicating deletion of Prlr from Rip-Cre neurones. By contrast, no co-localisation of td-tomato and pSTAT5 was observed in td-tomato/Agrp-Cre mice after prolactin treatment. Moreover, Prlr lox/lox /Agrp-Cre mice had no positive GFP staining in the arcuate nucleus and did not differ in body weight compared to littermate controls. Overall, these results indicate that Rip-Cre neurones in the arcuate nucleus are

  19. A BAC-based transgenic mouse specifically expresses an inducible Cre in the urothelium.

    Directory of Open Access Journals (Sweden)

    Tian Huai Shen

    Full Text Available Cre-loxp mediated conditional knockout strategy has played critical roles for revealing functions of many genes essential for development, as well as the causal relationships between gene mutations and diseases in the postnatal adult mice. One key factor of this strategy is the availability of mice with tissue- or cell type-specific Cre expression. However, the success of the traditional molecular cloning approach to generate mice with tissue specific Cre expression often depends on luck. Here we provide a better alternative by using bacterial artificial chromosome (BAC-based recombineering to insert iCreERT2 cDNA at the ATG start of the Upk2 gene. The BAC-based transgenic mice express the inducible Cre specifically in the urothelium as demonstrated by mRNA expression and staining for LacZ expression after crossing with a Rosa26 reporter mouse. Taking into consideration the size of the gene of interest and neighboring genes included in a BAC, this method should be widely applicable for generation of mice with tissue specific gene expression or deletions in a more specific manner than previously reported.

  20. Deletion of creB in Aspergillus oryzae increases secreted hydrolytic enzyme activity.

    Science.gov (United States)

    Hunter, A J; Morris, T A; Jin, B; Saint, C P; Kelly, J M

    2013-09-01

    Aspergillus oryzae has been used in the food and beverage industry for centuries, and industrial strains have been produced by multiple rounds of selection. Targeted gene deletion technology is particularly useful for strain improvement in such strains, particularly when they do not have a well-characterized meiotic cycle. Phenotypes of an Aspergillus nidulans strain null for the CreB deubiquitinating enzyme include effects on growth and repression, including increased activity levels of various enzymes. We show that Aspergillus oryzae contains a functional homologue of the CreB deubiquitinating enzyme and that a null strain shows increased activity levels of industrially important secreted enzymes, including cellulases, xylanases, amylases, and proteases, as well as alleviated inhibition of spore germination on glucose medium. Reverse transcription-quantitative PCR (RT-qPCR) analysis showed that the increased levels of enzyme activity in both Aspergillus nidulans and Aspergillus oryzae are mirrored at the transcript level, indicating transcriptional regulation. We report that Aspergillus oryzae DAR3699, originally isolated from soy fermentation, has a similar phenotype to that of a creB deletion mutant of the RIB40 strain, and it contains a mutation in the creB gene. Collectively, the results for Aspergillus oryzae, Aspergillus nidulans, Trichoderma reesei, and Penicillium decumbens show that deletion of creB may be broadly useful in diverse fungi for increasing production of a variety of enzymes.

  1. Deletion of Munc18-1 in 5-HT Neurons Results in Rapid Degeneration of the 5-HT System and Early Postnatal Lethality

    NARCIS (Netherlands)

    Dudok, J.J.; Groffen, A.J.A.; Toonen, R.F.G.; Verhage, M.

    2011-01-01

    The serotonin (5-HT) system densely innervates many brain areas and is important for proper brain development. To specifically ablate the 5-HT system we generated mutant mice carrying a floxed Munc18-1 gene and Cre recombinase driven by the 5-HT-specific serotonin reuptake transporter (SERT)

  2. Disruption of Trichoderma reesei cre2, encoding an ubiquitin C-terminal hydrolase, results in increased cellulase activity

    Science.gov (United States)

    2011-01-01

    Background The filamentous fungus Trichoderma reesei (Hypocrea jecorina) is an important source of cellulases for use in the textile and alternative fuel industries. To fully understand the regulation of cellulase production in T. reesei, the role of a gene known to be involved in carbon regulation in Aspergillus nidulans, but unstudied in T. reesei, was investigated. Results The T. reesei orthologue of the A. nidulans creB gene, designated cre2, was identified and shown to be functional through heterologous complementation of a creB mutation in A. nidulans. A T. reesei strain was constructed using gene disruption techniques that contained a disrupted cre2 gene. This strain, JKTR2-6, exhibited phenotypes similar to the A. nidulans creB mutant strain both in carbon catabolite repressing, and in carbon catabolite derepressing conditions. Importantly, the disruption also led to elevated cellulase levels. Conclusions These results demonstrate that cre2 is involved in cellulase expression. Since the disruption of cre2 increases the amount of cellulase activity, without severe morphological affects, targeting creB orthologues for disruption in other industrially useful filamentous fungi, such as Aspergillus oryzae, Trichoderma harzianum or Aspergillus niger may also lead to elevated hydrolytic enzyme activity in these species. PMID:22070776

  3. Disruption of Trichoderma reesei cre2, encoding an ubiquitin C-terminal hydrolase, results in increased cellulase activity

    Directory of Open Access Journals (Sweden)

    Denton Jai A

    2011-11-01

    Full Text Available Abstract Background The filamentous fungus Trichoderma reesei (Hypocrea jecorina is an important source of cellulases for use in the textile and alternative fuel industries. To fully understand the regulation of cellulase production in T. reesei, the role of a gene known to be involved in carbon regulation in Aspergillus nidulans, but unstudied in T. reesei, was investigated. Results The T. reesei orthologue of the A. nidulans creB gene, designated cre2, was identified and shown to be functional through heterologous complementation of a creB mutation in A. nidulans. A T. reesei strain was constructed using gene disruption techniques that contained a disrupted cre2 gene. This strain, JKTR2-6, exhibited phenotypes similar to the A. nidulans creB mutant strain both in carbon catabolite repressing, and in carbon catabolite derepressing conditions. Importantly, the disruption also led to elevated cellulase levels. Conclusions These results demonstrate that cre2 is involved in cellulase expression. Since the disruption of cre2 increases the amount of cellulase activity, without severe morphological affects, targeting creB orthologues for disruption in other industrially useful filamentous fungi, such as Aspergillus oryzae, Trichoderma harzianum or Aspergillus niger may also lead to elevated hydrolytic enzyme activity in these species.

  4. Anomalous baroreflex functionality inherent in floxed and Cre-Lox mice: an overlooked physiological phenotype.

    Science.gov (United States)

    Tsai, Ching-Yi; Poon, Yan-Yuen; Chen, Chang-Han; Chan, Samuel H H

    2017-10-01

    The last two decades have seen the emergence of Cre-Lox recombination as one of the most powerful and versatile technologies for cell-specific genetic engineering of mammalian cells. Understandably, the primary concerns in the practice of Cre-Lox recombination are whether the predicted genome has been correctly modified and the targeted phenotypes expressed. Rarely are the physiological conditions of the animals routinely examined because the general assumption is that they are normal. Based on corroborative results from radiotelemetric recording, power spectral analysis, and magnetic resonance imaging/diffusion tensor imaging in brain-derived neurotrophic factor-floxed mice, the present study revealed that this assumption requires amendment. We found that despite comparable blood pressure and heart rate with C57BL/6 or Cre mice under the conscious state, floxed and Cre-Lox mice exhibited diminished baroreflex-mediated sympathetic vasomotor tone and cardiac vagal baroreflex. We further found that the capacity and plasticity of baroreflex of these two strains of mice under isoflurane anesthesia were retarded, as reflected by reduced connectivity between the nucleus tractus solitarii and rostral ventrolateral medulla or nucleus ambiguus. The identification of anomalous baroreflex functionality inherent in floxed and Cre-Lox mice points to the importance of incorporating physiological phenotypes into studies that engage gene manipulations such as Cre-Lox recombination. NEW & NOTEWORTHY We established that anomalous baroreflex functionality is inherent in floxed and Cre-Lox mice. These two mouse strains exhibited diminished baroreflex-mediated sympathetic vasomotor tone and cardiac vagal baroreflex under the conscious state, retarded capacity and plasticity of baroreflex under isoflurane anesthesia, and reduced connectivity between key nuclei in the baroreflex neural circuits. Copyright © 2017 the American Physiological Society.

  5. Cre-mediated stress affects sirtuin expression levels, peroxisome biogenesis and metabolism, antioxidant and proinflammatory signaling pathways.

    Directory of Open Access Journals (Sweden)

    Yu Xiao

    Full Text Available Cre-mediated excision of loxP sites is widely used in mice to manipulate gene function in a tissue-specific manner. To analyze phenotypic alterations related to Cre-expression, we have used AMH-Cre-transgenic mice as a model system. Different Cre expression levels were obtained by investigation of C57BL/6J wild type as well as heterozygous and homozygous AMH-Cre-mice. Our results indicate that Cre-expression itself in Sertoli cells already has led to oxidative stress and lipid peroxidation (4-HNE lysine adducts, inducing PPARα/γ, peroxisome proliferation and alterations of peroxisome biogenesis (PEX5, PEX13 and PEX14 as well as metabolic proteins (ABCD1, ABCD3, MFP1, thiolase B, catalase. In addition to the strong catalase increase, a NRF2- and FOXO3-mediated antioxidative response (HMOX1 of the endoplasmic reticulum and mitochondrial SOD2 and a NF-κB activation were noted. TGFβ1 and proinflammatory cytokines like IL1, IL6 and TNFα were upregulated and stress-related signaling pathways were induced. Sertoli cell mRNA-microarray analysis revealed an increase of TNFR2-signaling components. 53BP1 recruitment and expression levels for DNA repair genes as well as for p53 were elevated and the ones for related sirtuin deacetylases affected (SIRT 1, 3-7 in Sertoli cells. Under chronic Cre-mediated DNA damage conditions a strong downregulation of Sirt1 was observed, suggesting that the decrease of this important coordinator between DNA repair and metabolic signaling might induce the repression release of major transcription factors regulating metabolic and cytokine-mediated stress pathways. Indeed, caspase-3 was activated and increased germ cell apoptosis was observed, suggesting paracrine effects. In conclusion, the observed wide stress-induced effects and metabolic alterations suggest that it is essential to use the correct control animals (Cre/Wt with matched Cre expression levels to differentiate between Cre-mediated and specific gene-knock out

  6. Cre-Mediated Stress Affects Sirtuin Expression Levels, Peroxisome Biogenesis and Metabolism, Antioxidant and Proinflammatory Signaling Pathways

    Science.gov (United States)

    Xiao, Yu; Karnati, Srikanth; Qian, Guofeng; Nenicu, Anca; Fan, Wei; Tchatalbachev, Svetlin; Höland, Anita; Hossain, Hamid; Guillou, Florian; Lüers, Georg H.; Baumgart-Vogt, Eveline

    2012-01-01

    Cre-mediated excision of loxP sites is widely used in mice to manipulate gene function in a tissue-specific manner. To analyze phenotypic alterations related to Cre-expression, we have used AMH-Cre-transgenic mice as a model system. Different Cre expression levels were obtained by investigation of C57BL/6J wild type as well as heterozygous and homozygous AMH-Cre-mice. Our results indicate that Cre-expression itself in Sertoli cells already has led to oxidative stress and lipid peroxidation (4-HNE lysine adducts), inducing PPARα/γ, peroxisome proliferation and alterations of peroxisome biogenesis (PEX5, PEX13 and PEX14) as well as metabolic proteins (ABCD1, ABCD3, MFP1, thiolase B, catalase). In addition to the strong catalase increase, a NRF2- and FOXO3-mediated antioxidative response (HMOX1 of the endoplasmic reticulum and mitochondrial SOD2) and a NF-κB activation were noted. TGFβ1 and proinflammatory cytokines like IL1, IL6 and TNFα were upregulated and stress-related signaling pathways were induced. Sertoli cell mRNA-microarray analysis revealed an increase of TNFR2-signaling components. 53BP1 recruitment and expression levels for DNA repair genes as well as for p53 were elevated and the ones for related sirtuin deacetylases affected (SIRT 1, 3-7) in Sertoli cells. Under chronic Cre-mediated DNA damage conditions a strong downregulation of Sirt1 was observed, suggesting that the decrease of this important coordinator between DNA repair and metabolic signaling might induce the repression release of major transcription factors regulating metabolic and cytokine-mediated stress pathways. Indeed, caspase-3 was activated and increased germ cell apoptosis was observed, suggesting paracrine effects. In conclusion, the observed wide stress-induced effects and metabolic alterations suggest that it is essential to use the correct control animals (Cre/Wt) with matched Cre expression levels to differentiate between Cre-mediated and specific gene-knock out

  7. Notch Inhibits Osteoblast Differentiation and Causes Osteopenia

    Science.gov (United States)

    Zanotti, Stefano; Smerdel-Ramoya, Anna; Stadmeyer, Lisa; Durant, Deena; Radtke, Freddy; Canalis, Ernesto

    2008-01-01

    Notch receptors are determinants of cell fate decisions. To define the role of Notch in the adult skeleton, we created transgenic mice overexpressing the Notch intracellular domain (NICD) under the control of the type I collagen promoter. First-generation transgenics were small and osteopenic. Bone histomorphometry revealed that NICD caused a decrease in bone volume, secondary to a reduction in trabecular number; osteoblast and osteoclast number were decreased. Low fertility of founder mice and lethality of young pups did not allow the complete establishment of transgenic lines. To characterize the effect of Notch overexpression in vitro, NICD was induced in osteoblasts and stromal cells from Rosanotch mice, in which a STOP cassette flanked by loxP sites is upstream of NICD, by transduction with an adenoviral vector expressing Cre recombinase (Cre) under the control of the cytomegalovirus (CMV) promoter (Ad-CMV-Cre). NICD impaired osteoblastogenesis and inhibited Wnt/β-catenin signaling. To determine the effects of notch1 deletion in vivo, mice in which notch1 was flanked by loxP sequences (notch1loxP/loxP) were mated with mice expressing Cre recombinase under the control of the osteocalcin promoter. Conditional null notch1 mice had no obvious skeletal phenotype, possibly because of rescue by notch2; however, 1-month-old females exhibited a modest increase in osteoclast surface and eroded surface. Osteoblasts from notch1loxP/loxP mice, transduced with Ad-CMV-Cre and transfected with Notch2 small interfering RNA, displayed increased alkaline phosphatase activity. In conclusion, Notch signaling in osteoblasts causes osteopenia and impairs osteo-blastogenesis by inhibiting the Wnt/β-catenin pathway. PMID:18420737

  8. CDC Vital Signs: Making Health Care Safer -- Stop Infections from Lethal CRE Germs Now

    Science.gov (United States)

    ... to patients with CRE; and improving use of gloves and gowns. Result: The percentage of patients who got CRE at the facility dropped from 44% to 0. Top of Page What Can Be Done Federal Government ...

  9. Production of Cellulases by Rhizopus stolonifer from Glucose-Containing Media Based on the Regulation of Transcriptional Regulator CRE.

    Science.gov (United States)

    Zhang, Yingyiing; Tang, Bin; Du, Guocheng

    2017-03-28

    Carbon catabolite repression is a crucial regulation mechanism in microorganisms, but its characteristic in Rhizopus is still unclear. We extracted a carbon regulation gene, cre , that encoded a carbon catabolite repressor protein (CRE) from Rhizopus stolonifer TP-02, and studied the regulation of CRE by real-time qPCR. CRE responded to glucose in a certain range, where it could significantly regulate part of the cellulase genes ( eg, bg, and cbh2 ) without cbh1 . In the comparison of the response of cre and four cellulase genes to carboxymethylcellulose sodium and a simple carbon source (lactose), the effect of CRE was only related to the concentration of reducing sugars. By regulating the reducing sugars to range from 0.4% to 0.6%, a glucose-containing medium with lactose as the inducer could effectively induce cellulases without the repression of CRE. This regulation method could potentially reduce the cost of enzymes produced in industries and provide a possible solution to achieve the large-scale synthesis of cellulases.

  10. Fabp4-Cre-mediated Sirt6 deletion impairs adipose tissue function and metabolic homeostasis in mice.

    Science.gov (United States)

    Xiong, Xiwen; Zhang, Cuicui; Zhang, Yang; Fan, Rui; Qian, Xinlai; Dong, X Charlie

    2017-06-01

    SIRT6 is a member of sirtuin family of deacetylases involved in diverse processes including genome stability, metabolic homeostasis and anti-inflammation. However, its function in the adipose tissue is not well understood. To examine the metabolic function of SIRT6 in the adipose tissue, we generated two mouse models that are deficient in Sirt6 using the Cre-lox approach. Two commonly used Cre lines that are driven by either the mouse Fabp4 or Adipoq gene promoter were chosen for this study. The Sirt6- knockout mice generated by the Fabp4-Cre line ( Sirt6 f/f : Fabp4-Cre) had a significant increase in both body weight and fat mass and exhibited glucose intolerance and insulin resistance as compared with the control wild-type mice. At the molecular levels, the Sirt6 f/f :Fabp4-Cre-knockout mice had increased expression of inflammatory genes including F4/80, TNFα, IL-6 and MCP-1 in both white and brown adipose tissues. Moreover, the knockout mice showed decreased expression of the adiponectin gene in the white adipose tissue and UCP1 in the brown adipose tissue, respectively. In contrast, the Sirt6 knockout mice generated by the Adipoq-Cre line ( Sirt6 f/f :Adipoq-Cre) only had modest insulin resistance. In conclusion, our data suggest that the function of SIRT6 in the Fabp4-Cre-expressing cells in addition to mature adipocytes plays a critical role in body weight maintenance and metabolic homeostasis. © 2017 Society for Endocrinology.

  11. Vika/vox, a novel efficient and specific Cre/loxP-like site-specific recombination system

    Science.gov (United States)

    Karimova, Madina; Abi-Ghanem, Josephine; Berger, Nicolas; Surendranath, Vineeth; Pisabarro, Maria Teresa; Buchholz, Frank

    2013-01-01

    Targeted genome engineering has become an important research area for diverse disciplines, with site-specific recombinases (SSRs) being among the most popular genome engineering tools. Their ability to trigger excision, integration, inversion and translocation has made SSRs an invaluable tool to manipulate DNA in vitro and in vivo. However, sophisticated strategies that combine different SSR systems are ever increasing. Hence, the demand for additional precise and efficient recombinases is dictated by the increasing complexity of the genetic studies. Here, we describe a novel site-specific recombination system designated Vika/vox. Vika originates from a degenerate bacteriophage of Vibrio coralliilyticus and shares low sequence similarity to other tyrosine recombinases, but functionally carries out a similar type of reaction. We demonstrate that Vika is highly specific in catalyzing vox recombination without recombining target sites from other SSR systems. We also compare the recombination activity of Vika/vox with other SSR systems, providing a guideline for deciding on the most suitable enzyme for a particular application and demonstrate that Vika expression does not cause cytotoxicity in mammalian cells. Our results show that Vika/vox is a novel powerful and safe instrument in the ‘genetic toolbox’ that can be used alone or in combination with other SSRs in heterologous hosts. PMID:23143104

  12. Commission for Energy regulation (CRE) - Activity report June 2005; Commission de regulation de l'energie (CRE) - Rapport d'activite juin 2005

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    CRE is the French commission for energy regulation. CRE's remit is to assist in ensuring the proper operation of the electricity and natural gas markets for the benefit of the end-user. In particular, CRE ensures that the conditions of access to electricity and natural gas transmission and distribution systems do not hinder the development of competition. It monitors, for the electricity and natural gas sectors, all transactions made between suppliers, traders and producers, all transactions made on the organised markets and cross-border trading. It ensures that suppliers, traders and producers propose offers that are consistent with their financial and technical constraints. It monitors the implementation of and compliance with regulations giving consumers the right to choose their supplier in a competitive market, and allowing new suppliers to enter the market. This document is the 2005 activity report of CRE. Content: A - The opening of the markets in France and in Europe: The opening of the markets one year after 1 July 2004 (An especially important step, Electricity and gas: a common framework with structural differences, The coexistence of market prices and regulated tariffs); The European texts of 26 June 2003 (Texts to give new impetus, Texts to harmonize the role and powers of national regulators, Texts to guarantee the independence of system operators, Texts to ensure transparent and non-discriminatory access to networks, Texts providing for strengthening of interconnections); The outlook for 2007, a fully open market (1 July 2007: a date set by the directives, Priority given to informing and protecting consumers); B - Regulation of the natural gas market: The gas market in the European context (Europe's dependency on imports is increasing, Gas prices increased considerably across the whole of Europe in 2004, The European gas scene continues to be dominated by a small number of players, Gas infrastructures need to be developed in Europe, The new

  13. Overlapping ETS and CRE Motifs (G/CCGGAAGTGACGTCA) Preferentially Bound by GABPα and CREB Proteins

    Science.gov (United States)

    Chatterjee, Raghunath; Zhao, Jianfei; He, Ximiao; Shlyakhtenko, Andrey; Mann, Ishminder; Waterfall, Joshua J.; Meltzer, Paul; Sathyanarayana, B. K.; FitzGerald, Peter C.; Vinson, Charles

    2012-01-01

    Previously, we identified 8-bps long DNA sequences (8-mers) that localize in human proximal promoters and grouped them into known transcription factor binding sites (TFBS). We now examine split 8-mers consisting of two 4-mers separated by 1-bp to 30-bps (X4-N1-30-X4) to identify pairs of TFBS that localize in proximal promoters at a precise distance. These include two overlapping TFBS: the ETS⇔ETS motif (C/GCCGGAAGCGGAA) and the ETS⇔CRE motif (C/GCGGAAGTGACGTCAC). The nucleotides in bold are part of both TFBS. Molecular modeling shows that the ETS⇔CRE motif can be bound simultaneously by both the ETS and the B-ZIP domains without protein-protein clashes. The electrophoretic mobility shift assay (EMSA) shows that the ETS protein GABPα and the B-ZIP protein CREB preferentially bind to the ETS⇔CRE motif only when the two TFBS overlap precisely. In contrast, the ETS domain of ETV5 and CREB interfere with each other for binding the ETS⇔CRE. The 11-mer (CGGAAGTGACG), the conserved part of the ETS⇔CRE motif, occurs 226 times in the human genome and 83% are in known regulatory regions. In vivo GABPα and CREB ChIP-seq peaks identified the ETS⇔CRE as the most enriched motif occurring in promoters of genes involved in mRNA processing, cellular catabolic processes, and stress response, suggesting that a specific class of genes is regulated by this composite motif. PMID:23050235

  14. Rearrangement of RAG-1 recombinase gene in radiation-sensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Weaver, P.

    1994-01-01

    The recent cloning and characterization of recombinase genes (RAG- 1/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice (wst). Our results revealed expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/sm-bullet mice). In thymus tissue, a small RAG-1 transcript was detected in wst/wst mice that was not evident in thymus from control mice. In wst/lg-bullet mice, a two-fold increase in RAG-1 mRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/sm-bullet and not from wst;/wst or parental control BCF 1 mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage

  15. Establishment of a tamoxifen-inducible Cre-driver mouse strain for widespread and temporal genetic modification in adult mice.

    Science.gov (United States)

    Ichise, Hirotake; Hori, Akiko; Shiozawa, Seiji; Kondo, Saki; Kanegae, Yumi; Saito, Izumu; Ichise, Taeko; Yoshida, Nobuaki

    2016-07-29

    Temporal genetic modification of mice using the ligand-inducible Cre/loxP system is an important technique that allows the bypass of embryonic lethal phenotypes and access to adult phenotypes. In this study, we generated a tamoxifen-inducible Cre-driver mouse strain for the purpose of widespread and temporal Cre recombination. The new line, named CM32, expresses the GFPneo-fusion gene in a wide variety of tissues before FLP recombination and tamoxifen-inducible Cre after FLP recombination. Using FLP-recombined CM32 mice (CM32Δ mice) and Cre reporter mouse lines, we evaluated the efficiency of Cre recombination with and without tamoxifen administration to adult mice, and found tamoxifen-dependent induction of Cre recombination in a variety of adult tissues. In addition, we demonstrated that conditional activation of an oncogene could be achieved in adults using CM32Δ mice. CM32Δ;T26 mice, which harbored a Cre recombination-driven, SV40 large T antigen-expressing transgene, were viable and fertile. No overt phenotype was found in the mice up to 3 months after birth. Although they displayed pineoblastomas (pinealoblastomas) and/or thymic enlargement due to background Cre recombination by 6 months after birth, they developed epidermal hyperplasia when administered tamoxifen. Collectively, our results suggest that the CM32Δ transgenic mouse line can be applied to the assessment of adult phenotypes in mice with loxP-flanked transgenes.

  16. Targeted deletion of RANKL in M cell inducer cells by the Col6a1-Cre driver.

    Science.gov (United States)

    Nagashima, Kazuki; Sawa, Shinichiro; Nitta, Takeshi; Prados, Alejandro; Koliaraki, Vasiliki; Kollias, George; Nakashima, Tomoki; Takayanagi, Hiroshi

    2017-11-04

    The gut-associated lymphoid tissues (GALTs), including Peyer's patches (PPs), cryptopatches (CPs) and isolated lymphoid follicles (ILFs), establish a host-microbe symbiosis by the promotion of immune reactions against gut microbes. Microfold cell inducer (MCi) cells in GALTs are the recently identified mesenchymal cells that express the cytokine RANKL and initiate bacteria-specific immunoglobulin A (IgA) production via induction of microfold (M) cell differentiation. In the previous study, the Twist2-Cre driver was utilized for gene deletion in mesenchymal cells including MCi cells. In order to investigate MCi cells more extensively, it will be necessary to develop experimental tools in addition to the Twist2-Cre driver mice and characterize such drivers in specificity and efficiency. Here we show that M cell differentiation and IgA production are impaired in the targeted deletion of RANKL by the Col6a1-Cre driver. We compared Col6a1-Cre with Twist2-Cre in terms of the specificity for mesenchymal cells in GALTs. Col6a1-Cre CAG-CAT-EGFP mice exhibited EGFP expression in podoplanin + CD31 - cells including MCi cells, while Twist2-Cre mice were shown to target endothelial cells and podoplanin + CD31 - cells. Tnfsf11 fl/Δ Col6a1-Cre mice exhibited the absence of M cells and severe IgA reduction together with an alteration in gut microbial composition. Moreover, we analyzed germ free mice to test whether changes in the microbiota are the cause of M cell deficiency. M cell differentiation was normal in the CPs/ILFs of germ free mice, indicating that MCi cells induce M cells independently of microbial colonization. This study demonstrates that Col6a1-Cre driver mice are as useful as Twist2-Cre driver mice for functional analyses of GALT-resident mesenchymal cells, including MCi cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Carbapenem-resistant Enterobacteriaceae colonization (CRE) and subsequent risk of infection and 90-day mortality in critically ill patients, an observational study.

    Science.gov (United States)

    McConville, Thomas Howe; Sullivan, Sean Berger; Gomez-Simmonds, Angela; Whittier, Susan; Uhlemann, Anne-Catrin

    2017-01-01

    Carbapenem-resistant Enterobacteriaceae (CRE) have emerged as an urgent public health threat. Intestinal colonization with CRE has been identified as a risk factor for the development of systemic CRE infection, but has not been compared to colonization with third and/or fourth generation cephalosporin-resistant (Ceph-R) Enterobacteriaceae. Moreover, the risk conferred by colonization on adverse outcomes is less clear, particularly in critically ill patients admitted to the intensive care unit (ICU). We carried out a cohort study of consecutive adult patients screened for rectal colonization with CRE or Ceph-R upon ICU entry between April and July 2013. We identified clinical variables and assessed the relationship between CRE or Ceph-R colonization and subsequent systemic CRE infection within 30 days (primary outcome) and all-cause mortality within 90 days (secondary outcome). Among 338 ICU patients, 94 (28%) were colonized with either Ceph-R or CRE. 26 patients developed CRE infection within 30 days of swab collection; 47% (N = 17/36) of CRE-colonized and 3% (N = 2/58) of Ceph-R colonized patients. 36% (N = 13/36) of CRE-colonized patients died within 90 days compared to 31% (N = 18/58) of Ceph-R-colonized and 15% (N = 37/244) of non-colonized patients. In a multivariable analysis, CRE colonization independently predicted development of a systemic CRE infection at 30 days (aOR 10.8, 95% CI2.8-41.9, p = 0.0006); Ceph-R colonization did not (aOR 0.5, 95% CI0.1-3.3, p = 0.5). CRE colonization was associated with increased 90-day mortality in a univariable analysis (p-value 0.001), in a multivariable model, previous hospitalization and medical ICU admission were independent predictors of 90-day mortality whereas CRE colonization approached significance (aOR 2.3, 95% CI1.0-5.3, p = 0.056). Our study highlights the increased risk of CRE infection and mortality in patients with CRE colonization at the time of ICU admission. Future studies are needed to assess how CRE

  18. Cre/lox-based multiple markerless gene disruption in the genome of the extreme thermophile Thermus thermophilus.

    Science.gov (United States)

    Togawa, Yoichiro; Nunoshiba, Tatsuo; Hiratsu, Keiichiro

    2018-02-01

    Markerless gene-disruption technology is particularly useful for effective genetic analyses of Thermus thermophilus (T. thermophilus), which have a limited number of selectable markers. In an attempt to develop a novel system for the markerless disruption of genes in T. thermophilus, we applied a Cre/lox system to construct a triple gene disruptant. To achieve this, we constructed two genetic tools, a loxP-htk-loxP cassette and cre-expressing plasmid, pSH-Cre, for gene disruption and removal of the selectable marker by Cre-mediated recombination. We found that the Cre/lox system was compatible with the proliferation of the T. thermophilus HB27 strain at the lowest growth temperature (50 °C), and thus succeeded in establishing a triple gene disruptant, the (∆TTC1454::loxP, ∆TTC1535KpnI::loxP, ∆TTC1576::loxP) strain, without leaving behind a selectable marker. During the process of the sequential disruption of multiple genes, we observed the undesired deletion and inversion of the chromosomal region between multiple loxP sites that were induced by Cre-mediated recombination. Therefore, we examined the effects of a lox66-htk-lox71 cassette by exploiting the mutant lox sites, lox66 and lox71, instead of native loxP sites. We successfully constructed a (∆TTC1535::lox72, ∆TTC1537::lox72) double gene disruptant without inducing the undesired deletion of the 0.7-kbp region between the two directly oriented lox72 sites created by the Cre-mediated recombination of the lox66-htk-lox71 cassette. This is the first demonstration of a Cre/lox system being applicable to extreme thermophiles in a genetic manipulation. Our results indicate that this system is a powerful tool for multiple markerless gene disruption in T. thermophilus.

  19. FLP recombinase-mediated site-specific recombination in silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Ding-Pei Long

    Full Text Available A comprehensive understanding of gene function and the production of site-specific genetically modified mutants are two major goals of genetic engineering in the post-genomic era. Although site-specific recombination systems have been powerful tools for genome manipulation of many organisms, they have not yet been established for use in the manipulation of the silkworm Bombyx mori genome. In this study, we achieved site-specific excision of a target gene at predefined chromosomal sites in the silkworm using a FLP/FRT site-specific recombination system. We first constructed two stable transgenic target silkworm strains that both contain a single copy of the transgene construct comprising a target gene expression cassette flanked by FRT sites. Using pre-blastoderm microinjection of a FLP recombinase helper expression vector, 32 G3 site-specific recombinant transgenic individuals were isolated from five of 143 broods. The average frequency of FLP recombinase-mediated site-specific excision in the two target strains genome was approximately 3.5%. This study shows that it is feasible to achieve site-specific recombination in silkworms using the FLP/FRT system. We conclude that the FLP/FRT system is a useful tool for genome manipulation in the silkworm. Furthermore, this is the first reported use of the FLP/FRT system for the genetic manipulation of a lepidopteran genome and thus provides a useful reference for the establishment of genome manipulation technologies in other lepidopteran species.

  20. A high throughput Cre–lox activated viral membrane fusion assay identifies pharmacological inhibitors of HIV entry

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Anthony M. [Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, Immunology Institute, New York, NY (United States); Cheung, Pamela [Integrated Screening Core, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Swartz, Talia H.; Li, Hongru [Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, Immunology Institute, New York, NY (United States); Tsibane, Tshidi [Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Durham, Natasha D. [Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, Immunology Institute, New York, NY (United States); Basler, Christopher F. [Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Felsenfeld, Dan P. [Integrated Screening Core, Icahn School of Medicine at Mount Sinai, New York, NY (United States); Chen, Benjamin K., E-mail: benjamin.chen@mssm.edu [Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, Immunology Institute, New York, NY (United States)

    2016-03-15

    Enveloped virus entry occurs when viral and cellular membranes fuse releasing particle contents into the target cell. Human immunodeficiency virus (HIV) entry occurs by cell-free virus or virus transferred between infected and uninfected cells through structures called virological synapses. We developed a high-throughput cell-based assay to identify small molecule inhibitors of cell-free or virological synapse-mediated entry. An HIV clone carrying Cre recombinase as a Gag-internal gene fusion releases active Cre into cells upon viral entry activating a recombinatorial gene switch changing dsRed to GFP-expression. A screen of a 1998 known-biological profile small molecule library identified pharmacological HIV entry inhibitors that block both cell-free and cell-to-cell infection. Many top hits were noted as HIV inhibitors in prior studies, but not previously recognized as entry antagonists. Modest therapeutic indices for simvastatin and nigericin were observed in confirmatory HIV infection assays. This robust assay is adaptable to study HIV and heterologous viral pseudotypes. - Highlights: • Cre recombinase viral fusion assay screens cell-free or cell–cell entry inhibitors. • This Gag-iCre based assay is specific for the entry step of HIV replication. • Screened a library of known pharmacologic compounds for HIV fusion antagonists. • Many top hits were previously noted as HIV inhibitors, but here are classified as entry antagonists. Many top hits were previously noted as HIV inhibitors, but not as entry antagonists. • The assay is compatible with pseudotyping with HIV and heterologous viruses.

  1. A high throughput Cre–lox activated viral membrane fusion assay identifies pharmacological inhibitors of HIV entry

    International Nuclear Information System (INIS)

    Esposito, Anthony M.; Cheung, Pamela; Swartz, Talia H.; Li, Hongru; Tsibane, Tshidi; Durham, Natasha D.; Basler, Christopher F.; Felsenfeld, Dan P.; Chen, Benjamin K.

    2016-01-01

    Enveloped virus entry occurs when viral and cellular membranes fuse releasing particle contents into the target cell. Human immunodeficiency virus (HIV) entry occurs by cell-free virus or virus transferred between infected and uninfected cells through structures called virological synapses. We developed a high-throughput cell-based assay to identify small molecule inhibitors of cell-free or virological synapse-mediated entry. An HIV clone carrying Cre recombinase as a Gag-internal gene fusion releases active Cre into cells upon viral entry activating a recombinatorial gene switch changing dsRed to GFP-expression. A screen of a 1998 known-biological profile small molecule library identified pharmacological HIV entry inhibitors that block both cell-free and cell-to-cell infection. Many top hits were noted as HIV inhibitors in prior studies, but not previously recognized as entry antagonists. Modest therapeutic indices for simvastatin and nigericin were observed in confirmatory HIV infection assays. This robust assay is adaptable to study HIV and heterologous viral pseudotypes. - Highlights: • Cre recombinase viral fusion assay screens cell-free or cell–cell entry inhibitors. • This Gag-iCre based assay is specific for the entry step of HIV replication. • Screened a library of known pharmacologic compounds for HIV fusion antagonists. • Many top hits were previously noted as HIV inhibitors, but here are classified as entry antagonists. Many top hits were previously noted as HIV inhibitors, but not as entry antagonists. • The assay is compatible with pseudotyping with HIV and heterologous viruses.

  2. The carboxy-terminal αN helix of the archaeal XerA tyrosine recombinase is a molecular switch to control site-specific recombination.

    Science.gov (United States)

    Serre, Marie-Claude; El Arnaout, Toufic; Brooks, Mark A; Durand, Dominique; Lisboa, Johnny; Lazar, Noureddine; Raynal, Bertrand; van Tilbeurgh, Herman; Quevillon-Cheruel, Sophie

    2013-01-01

    Tyrosine recombinases are conserved in the three kingdoms of life. Here we present the first crystal structure of a full-length archaeal tyrosine recombinase, XerA from Pyrococcus abyssi, at 3.0 Å resolution. In the absence of DNA substrate XerA crystallizes as a dimer where each monomer displays a tertiary structure similar to that of DNA-bound Tyr-recombinases. Active sites are assembled in the absence of dif except for the catalytic Tyr, which is extruded and located equidistant from each active site within the dimer. Using XerA active site mutants we demonstrate that XerA follows the classical cis-cleavage reaction, suggesting rearrangements of the C-terminal domain upon DNA binding. Surprisingly, XerA C-terminal αN helices dock in cis in a groove that, in bacterial tyrosine recombinases, accommodates in trans αN helices of neighbour monomers in the Holliday junction intermediates. Deletion of the XerA C-terminal αN helix does not impair cleavage of suicide substrates but prevents recombination catalysis. We propose that the enzymatic cycle of XerA involves the switch of the αN helix from cis to trans packing, leading to (i) repositioning of the catalytic Tyr in the active site in cis and (ii) dimer stabilisation via αN contacts in trans between monomers.

  3. The carboxy-terminal αN helix of the archaeal XerA tyrosine recombinase is a molecular switch to control site-specific recombination.

    Directory of Open Access Journals (Sweden)

    Marie-Claude Serre

    Full Text Available Tyrosine recombinases are conserved in the three kingdoms of life. Here we present the first crystal structure of a full-length archaeal tyrosine recombinase, XerA from Pyrococcus abyssi, at 3.0 Å resolution. In the absence of DNA substrate XerA crystallizes as a dimer where each monomer displays a tertiary structure similar to that of DNA-bound Tyr-recombinases. Active sites are assembled in the absence of dif except for the catalytic Tyr, which is extruded and located equidistant from each active site within the dimer. Using XerA active site mutants we demonstrate that XerA follows the classical cis-cleavage reaction, suggesting rearrangements of the C-terminal domain upon DNA binding. Surprisingly, XerA C-terminal αN helices dock in cis in a groove that, in bacterial tyrosine recombinases, accommodates in trans αN helices of neighbour monomers in the Holliday junction intermediates. Deletion of the XerA C-terminal αN helix does not impair cleavage of suicide substrates but prevents recombination catalysis. We propose that the enzymatic cycle of XerA involves the switch of the αN helix from cis to trans packing, leading to (i repositioning of the catalytic Tyr in the active site in cis and (ii dimer stabilisation via αN contacts in trans between monomers.

  4. Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

    Directory of Open Access Journals (Sweden)

    Jose Luis Ramirez-GarciaLuna

    Full Text Available In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1 mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2 re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3 the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

  5. Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

    Science.gov (United States)

    Ramirez-GarciaLuna, Jose Luis; Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H; Li, Ailian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Henderson, Janet E; Martineau, Paul A

    2017-01-01

    In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

  6. Androgen receptor signalling in Vascular Endothelial cells is dispensable for spermatogenesis and male fertility

    Directory of Open Access Journals (Sweden)

    O'Hara Laura

    2012-01-01

    Full Text Available Abstract Background Androgen signalling is essential both for male development and function of the male reproductive system in adulthood. Within the adult testis, Germ cells (GC do not express androgen receptor (AR suggesting androgen-mediated promotion of spermatogenesis must act via AR-expressing somatic cell-types. Several recent studies have exploited the Cre/lox system of conditional gene-targeting to ablate AR function from key somatic cell-types in order to establish the cell-specific role of AR in promotion of male fertility. In this study, we have used a similar approach to specifically ablate AR-signalling from Vascular Endothelial (VE cells, with a view to defining the significance of androgen signalling within this cell-type on spermatogenesis. Findings AR expression in VE cells of the testicular vasculature was confirmed using an antibody against AR. A Cre-inducible fluorescent reporter line was used to empirically establish the utility of a mouse line expressing Cre Recombinase driven by the Tie2-Promoter, for targeting VE cells. Immunofluorescent detection revealed expression of YFP (and therefore Cre Recombinase function limited to VE cells and an interstitial population of cells, believed to be macrophages, that did not express AR. Mating of Tie2-Cre males to females carrying a floxed AR gene produced Vascular Endothelial Androgen Receptor Knockout (VEARKO mice and littermate controls. Ablation of AR from all VE cells was confirmed; however, no significant differences in bodyweight or reproductive tissue weights could be detected in VEARKO animals and spermatogenesis and fertility was unaffected. Conclusions We demonstrate the successful generation and empirical validation of a cell-specific knockout of AR from VE cells, and conclude that AR expression in VE cells is not essential for spermatogenesis or male fertility.

  7. Cre-Lox Neurogenetics: 20 Years of Versatile Applications in Brain Research and Counting….

    Science.gov (United States)

    Tsien, Joe Z

    2016-01-01

    Defining and manipulating specific neurons in the brain has garnered enormous interest in recent years, because such an approach is now widely recognized as crucial for deepening our understanding of how the brain works. When I started exploring the Cre-loxP recombination for brain research in the early 1990s, it was written off as a dead-end project by a young fool. Yet over the past 20 years, Cre-lox recombination-mediated neurogenetics has emerged as one of the most powerful and versatile technology platforms for cell-specific gene knockouts, transgenic overexpression, Brainbow imaging, neural pathway tracing with retrovirus and CLARITY, chemical genetics, and optogenetics. Its popularity and greater utility in neuroscience research is also largely thanks to the NIH's bold Blueprint for Neuroscience Research Initiative to launch several Cre-driver resource projects, as well as individual laboratories and private research organizations. With newly-discovered, genetically-encoded molecules that are capable of responding to sonar and magnetic stimulation, for sonogenetics or magnetogenetics, respectively, or detecting rapid voltage changes in neurons, Cre-lox neurogenetics will continue to aid brain research for years to come.

  8. The FEM simulation of continuous rotary extrusion (CRE) of aluminum alloy AA3003

    Science.gov (United States)

    Rajendran, Nijenthan; Valberg, Henry; Misiolek, Wojciech Z.

    2017-10-01

    Continuous Rotary Extrusion (CRE) process is also known in literature under Conform TM name and it is mainly used for the continuous extrusion of Aluminum and Copper alloys. CRE use a feedstock in the form of rod, powders and chips, which are fed into the groove of the rotating wheel. As the wheel rotates the feedstock moves along with it due to friction with the wheel. Once the feedstock reaches the abutment the material deforms plastically and it is extruded through the die. CRE has lot to offer when compared to other more conventional extrusion processes such as low energy input, no limit in billet length as it is a continuous process as well as improved material physical properties due to plastic deformation under constant parameters. In this work a FEM model has been developed using Deform TM 3D, to study the metal flow and state variables of AA3003 CRE extrusion. The effect of extrusion wheel velocity has been investigated. The results show that increase in wheel velocity will heat up the feedstock metal due to high shear deformation and higher friction, which significantly changes metal flow conditions at the die exit.

  9. The effect of CreA in glucose and xylose catabolism in Aspergillus nidulans

    DEFF Research Database (Denmark)

    Prathumpai, Wai; Mcintyre, Mhairi; Nielsen, Jens

    2004-01-01

    The catabolism of glucose and xylose was studied in a wild type and creA deleted (carbon catabolite de-repressed) strain of Aspergillus nidulans. Both strains were cultivated in bioreactors with either glucose or xylose as the sole carbon source, or in the presence of both sugars. In the cultivat......The catabolism of glucose and xylose was studied in a wild type and creA deleted (carbon catabolite de-repressed) strain of Aspergillus nidulans. Both strains were cultivated in bioreactors with either glucose or xylose as the sole carbon source, or in the presence of both sugars...... on the sugar mixture, glucose repression of xylose utilisation was observed; with xylose utilisation occurring only after glucose was depleted. This phenomenon was not seen in the creA deleted strain, where glucose and xylose were catabolised simultaneously. Measurement of key metabolites and the activities...... of key enzymes in the xylose utilisation pathway revealed that xylose metabolism was occurring in the creA deleted strain, even at high glucose concentrations. Conversely, in the wild type strain, activities of the key enzymes for xylose metabolism increased only when the effects of glucose repression...

  10. Limited impact on glucose homeostasis of leptin receptor deletion from insulin- or proglucagon-expressing cells

    Directory of Open Access Journals (Sweden)

    Helen Soedling

    2015-09-01

    Conclusions/interpretation: The use here of a highly selective Cre recombinase indicates that leptin signalling plays a relatively minor, age- and sex-dependent role in the control of β cell function in the mouse. No in vivo role for leptin receptors on α cells, nor in other proglucagon-expressing cells, was detected in this study.

  11. Nerve growth factor enhances the CRE-dependent transcriptional activity activated by nobiletin in PC12 cells.

    Science.gov (United States)

    Takito, Jiro; Kimura, Junko; Kajima, Koji; Uozumi, Nobuyuki; Watanabe, Makoto; Yokosuka, Akihito; Mimaki, Yoshihiro; Nakamura, Masanori; Ohizumi, Yasushi

    2016-07-01

    Prevention and treatment of Alzheimer disease are urgent problems for elderly people in developed countries. We previously reported that nobiletin, a poly-methoxylated flavone from the citrus peel, improved the symptoms in various types of animal models of memory loss and activated the cAMP responsive element (CRE)-dependent transcription in PC12 cells. Nobiletin activated the cAMP/PKA/MEK/Erk/MAPK signaling pathway without using the TrkA signaling activated by nerve growth factor (NGF). Here, we examined the effect of combination of nobiletin and NGF on the CRE-dependent transcription in PC12 cells. Although NGF alone had little effect on the CRE-dependent transcription, NGF markedly enhanced the CRE-dependent transcription induced by nobiletin. The NGF-induced enhancement was neutralized by a TrkA antagonist, K252a. This effect of NGF was effective on the early signaling event elicited by nobiletin. These results suggested that there was crosstalk between NGF and nobiletin signaling in activating the CRE-dependent transcription in PC12 cells.

  12. Cre/lox-assisted non-invasive in vivo tracking of specific cell populations by positron emission tomography.

    Science.gov (United States)

    Thunemann, Martin; Schörg, Barbara F; Feil, Susanne; Lin, Yun; Voelkl, Jakob; Golla, Matthias; Vachaviolos, Angelos; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Olbrich, Marcus; Ehrlichmann, Walter; Reischl, Gerald; Griessinger, Christoph M; Langer, Harald F; Gawaz, Meinrad; Lang, Florian; Schäfers, Michael; Kneilling, Manfred; Pichler, Bernd J; Feil, Robert

    2017-09-05

    Many pathophysiological processes are associated with proliferation, migration or death of distinct cell populations. Monitoring specific cell types and their progeny in a non-invasive, longitudinal and quantitative manner is still challenging. Here we show a novel cell-tracking system that combines Cre/lox-assisted cell fate mapping with a thymidine kinase (sr39tk) reporter gene for cell detection by positron emission tomography (PET). We generate Rosa26-mT/sr39tk PET reporter mice and induce sr39tk expression in platelets, T lymphocytes or cardiomyocytes. As proof of concept, we demonstrate that our mouse model permits longitudinal PET imaging and quantification of T-cell homing during inflammation and cardiomyocyte viability after myocardial infarction. Moreover, Rosa26-mT/sr39tk mice are useful for whole-body characterization of transgenic Cre mice and to detect previously unknown Cre activity. We anticipate that the Cre-switchable PET reporter mice will be broadly applicable for non-invasive long-term tracking of selected cell populations in vivo.Non-invasive cell tracking is a powerful method to visualize cells in vivo under physiological and pathophysiological conditions. Here Thunemann et al. generate a mouse model for in vivo tracking and quantification of specific cell types by combining a PET reporter gene with Cre-dependent activation that can be exploited for any cell population for which a Cre mouse line is available.

  13. Isoeffect lines using TDF and CRE concepts

    International Nuclear Information System (INIS)

    Supe, S.J.; Sasane, J.B.; Supe, D.S.

    1980-01-01

    Isoeffect lines based on Ellis' Nominal Standard Dose concept, Orton's Time Dose and Fractionation Factor (TDF) concept, and Kirk et al's Cumulative Radiation Effect (CRE) concept give differing results of treatment planning. Experience with isoeffect lines based on the above concepts in planning in case of radiotherapy for carcinoma of bladder and carcinoma of uterine cervix is narrated. (M.G.B.)

  14. Induced Pluripotent Stem Cells Generated from P0-Cre;Z/EG Transgenic Mice.

    Science.gov (United States)

    Ogawa, Yasuhiro; Eto, Akira; Miyake, Chisato; Tsuchida, Nana; Miyake, Haruka; Takaku, Yasuhiro; Hagiwara, Hiroaki; Oishi, Kazuhiko

    2015-01-01

    Neural crest (NC) cells are a migratory, multipotent cell population that arises at the neural plate border, and migrate from the dorsal neural tube to their target tissues, where they differentiate into various cell types. Abnormal development of NC cells can result in severe congenital birth defects. Because only a limited number of cells can be obtained from an embryo, mechanistic studies are difficult to perform with directly isolated NC cells. Protein zero (P0) is expressed by migrating NC cells during the early embryonic period. In the P0-Cre;Z/EG transgenic mouse, transient activation of the P0 promoter induces Cre-mediated recombination, indelibly tagging NC-derived cells with enhanced green fluorescent protein (EGFP). Induced pluripotent stem cell (iPSC) technology offers new opportunities for both mechanistic studies and development of stem cell-based therapies. Here, we report the generation of iPSCs from the P0-Cre;Z/EG mouse. P0-Cre;Z/EG mouse-derived iPSCs (P/G-iPSCs) exhibited pluripotent stem cell properties. In lineage-directed differentiation studies, P/G-iPSCs were efficiently differentiated along the neural lineage while expressing EGFP. These results suggest that P/G-iPSCs are useful to study NC development and NC-associated diseases.

  15. Induced Pluripotent Stem Cells Generated from P0-Cre;Z/EG Transgenic Mice.

    Directory of Open Access Journals (Sweden)

    Yasuhiro Ogawa

    Full Text Available Neural crest (NC cells are a migratory, multipotent cell population that arises at the neural plate border, and migrate from the dorsal neural tube to their target tissues, where they differentiate into various cell types. Abnormal development of NC cells can result in severe congenital birth defects. Because only a limited number of cells can be obtained from an embryo, mechanistic studies are difficult to perform with directly isolated NC cells. Protein zero (P0 is expressed by migrating NC cells during the early embryonic period. In the P0-Cre;Z/EG transgenic mouse, transient activation of the P0 promoter induces Cre-mediated recombination, indelibly tagging NC-derived cells with enhanced green fluorescent protein (EGFP. Induced pluripotent stem cell (iPSC technology offers new opportunities for both mechanistic studies and development of stem cell-based therapies. Here, we report the generation of iPSCs from the P0-Cre;Z/EG mouse. P0-Cre;Z/EG mouse-derived iPSCs (P/G-iPSCs exhibited pluripotent stem cell properties. In lineage-directed differentiation studies, P/G-iPSCs were efficiently differentiated along the neural lineage while expressing EGFP. These results suggest that P/G-iPSCs are useful to study NC development and NC-associated diseases.

  16. Cre/lox Studies Identify Resident Macrophages as the Major Source of Circulating Coagulation Factor XIII-A.

    Science.gov (United States)

    Beckers, Cora M L; Simpson, Kingsley R; Griffin, Kathryn J; Brown, Jane M; Cheah, Lih T; Smith, Kerrie A; Vacher, Jean; Cordell, Paul A; Kearney, Mark T; Grant, Peter J; Pease, Richard J

    2017-08-01

    To establish the cellular source of plasma factor (F)XIII-A. A novel mouse floxed for the F13a1 gene, FXIII-A flox/flox (Flox), was crossed with myeloid- and platelet-cre-expressing mice, and cellular FXIII-A mRNA expression and plasma and platelet FXIII-A levels were measured. The platelet factor 4-cre.Flox cross abolished platelet FXIII-A and reduced plasma FXIII-A to 23±3% ( P cre on plasma FXIII-A was exerted outside of the megakaryocyte lineage because plasma FXIII-A was not reduced in the Mpl -/- mouse, despite marked thrombocytopenia. In support of this, platelet factor 4-cre depleted FXIII-A mRNA in brain, aorta, and heart of floxed mice, where FXIII-A pos cells were identified as macrophages as they costained with CD163. In the integrin αM-cre.Flox and the double copy lysozyme 2-cre.cre.Flox crosses, plasma FXIII-A was reduced to, respectively, 75±5% ( P =0.003) and 30±7% ( P <0.001), with no change in FXIII-A content per platelet, further consistent with a macrophage origin of plasma FXIII-A. The change in plasma FXIII-A levels across the various mouse genotypes mirrored the change in FXIII-A mRNA expression in aorta. Bone marrow transplantation of FXIII-A +/+ bone marrow into FXIII-A -/- mice both restored plasma FXIII-A to normal levels and replaced aortic and cardiac FXIII-A mRNA, while its transplantation into FXIII-A +/+ mice did not increase plasma FXIII-A levels, suggesting that a limited population of niches exists that support FXIII-A-releasing cells. This work suggests that resident macrophages maintain plasma FXIII-A and exclude the platelet lineage as a major contributor. © 2017 The Authors.

  17. Unintended targeting of Dmp1-Cre reveals a critical role for Bmpr1a signaling in the gastrointestinal mesenchyme of adult mice.

    Science.gov (United States)

    Lim, Joohyun; Burclaff, Joseph; He, Guangxu; Mills, Jason C; Long, Fanxin

    2017-01-01

    Cre/loxP technology has been widely used to study cell type-specific functions of genes. Proper interpretation of such data critically depends on a clear understanding of the tissue specificity of Cre expression. The Dmp1-Cre mouse, expressing Cre from a 14-kb DNA fragment of the mouse Dmp1 gene, has become a common tool for studying gene function in osteocytes, but the presumed cell specificity is yet to be fully established. By using the Ai9 reporter line that expresses a red fluorescent protein upon Cre recombination, we find that in 2-month-old mice, Dmp1-Cre targets not only osteocytes within the bone matrix but also osteoblasts on the bone surface and preosteoblasts at the metaphyseal chondro-osseous junction. In the bone marrow, Cre activity is evident in certain stromal cells adjacent to the blood vessels, but not in adipocytes. Outside the skeleton, Dmp1-Cre marks not only the skeletal muscle fibers, certain cells in the cerebellum and the hindbrain but also gastric and intestinal mesenchymal cells that express Pdgfra . Confirming the utility of Dmp1-Cre in the gastrointestinal mesenchyme, deletion of Bmpr1a with Dmp1-Cre causes numerous large polyps along the gastrointestinal tract, consistent with prior work involving inhibition of BMP signaling. Thus, caution needs to be exercised when using Dmp1-Cre because it targets not only the osteoblast lineage at an earlier stage than previously appreciated, but also a number of non-skeletal cell types.

  18. System's flips in climate-related energy (CRE) systems

    Science.gov (United States)

    Ramos, Maria-Helena; Creutin, Jean-Dominique; Engeland, Kolbjørn; François, Baptiste; Renard, Benjamin

    2014-05-01

    Several modern environmental questions invite to explore the complex relationships between natural phenomena and human behaviour at a range of space and time scales. This usually involves a number of cause-effect (causal) relationships, linking actions and events. In lay terms, 'effect' can be defined as 'what happened' and 'cause', 'why something happened.' In a changing world or merely moving from one scale to another, shifts in perspective are expected, bringing some phenomena into the foreground and putting others to the background. Systems can thus flip from one set of causal structures to another in response to environmental perturbations and human innovations or behaviors, for instance, as space-time signatures are modified. The identification of these flips helps in better understanding and predicting how societies and stakeholders react to a shift in perspective. In this study, our motivation is to investigate possible consequences of the shift to a low carbon economy in terms of socio-technico systems' flips. The focus is on the regional production of Climate-Related Energy (CRE) (hydro-, wind- and solar-power). We search for information on historic shifts that may help defining the forcing conditions of abrupt changes and extreme situations. We identify and present a series of examples in which we try to distinguish the various tipping points, thresholds, breakpoints and regime shifts that are characteristic of complex systems in the CRE production domain. We expect that with these examples our comprehension of the question will be enriched, providing us the elements needed to better validate modeling attempts, to predict and manage flips of complex CRE production systems. The work presented is part of the FP7 project COMPLEX (Knowledge based climate mitigation systems for a low carbon economy; http://www.complex.ac.uk/).

  19. Spinal Hb9::Cre-derived excitatory interneurons contribute to rhythm generation in the mouse

    DEFF Research Database (Denmark)

    Caldeira, Vanessa; Dougherty, Kimberly J.; Borgius, Lotta

    2017-01-01

    Rhythm generating neurons are thought to be ipsilaterally-projecting excitatory neurons in the thoracolumbar mammalian spinal cord. Recently, a subset of Shox2 interneurons (Shox2 non-V2a INs) was found to fulfill these criteria and make up a fraction of the rhythm-generating population. Here we...... than in cords from controls. Collectively, our findings indicate that excitatory Hb9::Cre-derived INs constitute a distinct population of neurons that participates in the rhythm generating kernel for spinal locomotion....... use Hb9::Cre mice to genetically manipulate Hb9::Cre-derived excitatory interneurons (INs) in order to determine the role of these INs in rhythm generation. We demonstrate that this line captures a consistent population of spinal INs which is mixed with respect to neurotransmitter phenotype...

  20. Isoeffect lines using TDF and CRE concepts

    International Nuclear Information System (INIS)

    Supe, S.J.; Sasane, J.B.; Gupta, M.K.; Supe, D.S.

    1979-01-01

    In most of the radiotherapy centres the treatment planning is based on isodose lines. Isoeffect lines are also being drawn based on the concepts of TDFs and CREs. A study has been made of whether the isoeffect lines based on the concepts of TDFs, CRes and the physical isodose lines are identical in all the treatment situations. Isoeffects lines for a few treatment schedules involving treatment of carcinoma of the bladder, treatment of cancer of the uterine cervix by combined intracavitary and external beam therapies and intracavitary therapy alone have been obtained and compared. The effect of treatment mode on the isoeffect lines has also been studied. It was found that the isodose curves and the isoeffect lines using the TDF and CRE concepts were not identical in all situations. Therefore, the ultimate treatment plans based on these isoeffect lines will not be exactly the same. The dependence of the isoeffect lines with the variation of the exponents of time and number of fractions used in the empirical relationship for NSD have also been investigated. Clinical trials have been initiated in the case of cancer of the bladder and cervix uterus based on the isodose curves and isoeffect lines using CRE and TDF concepts. (author)

  1. Rearrangement of RAG-1 recombinase gene in radiation-sensitive ''wasted'' mice

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Libertin, C.R.; Weaver, P.; Churchill, M.; Chang-Liu, C.M.

    1993-01-01

    Mice recessive for the autosomal gene ''wasted'' (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (RAG-1/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed expression of RAG-1 mRNA in spinal cord (but not brain) of control mice; no expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/· mice). In thymus tissue, a small RAG-1 transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/· mice, a two-fold increase in RAG-1 MRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/· and not from wst/wst or parental control BCF 1 mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage

  2. Rearrangement of RAG-1 recombinase gene in radiation-sensitive ``wasted`` mice

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, G.E. [Argonne National Lab., IL (United States)]|[Loyola Univ., Maywood, IL (United States); Libertin, C.R.; Weaver, P. [Loyola Univ., Maywood, IL (United States); Churchill, M.; Chang-Liu, C.M. [Argonne National Lab., IL (United States)

    1993-09-01

    Mice recessive for the autosomal gene ``wasted`` (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (RAG-1/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed expression of RAG-1 mRNA in spinal cord (but not brain) of control mice; no expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/{center_dot} mice). In thymus tissue, a small RAG-1 transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/{center_dot} mice, a two-fold increase in RAG-1 MRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/{center_dot} and not from wst/wst or parental control BCF{sub 1} mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

  3. Nonlocal symmetry and explicit solutions from the CRE method of the Boussinesq equation

    Science.gov (United States)

    Zhao, Zhonglong; Han, Bo

    2018-04-01

    In this paper, we analyze the integrability of the Boussinesq equation by using the truncated Painlevé expansion and the CRE method. Based on the truncated Painlevé expansion, the nonlocal symmetry and Bäcklund transformation of this equation are obtained. A prolonged system is introduced to localize the nonlocal symmetry to the local Lie point symmetry. It is proved that the Boussinesq equation is CRE solvable. The two-solitary-wave fusion solutions, single soliton solutions and soliton-cnoidal wave solutions are presented by means of the Bäcklund transformations.

  4. Development of CRTEIL and CETRIZ, Cre-loxP-Based Systems, Which Allow Change of Expression of Red to Green or Green to Red Fluorescence upon Transfection with a Cre-Expression Vector

    Directory of Open Access Journals (Sweden)

    Masato Ohtsuka

    2009-01-01

    Full Text Available We developed Cre-loxP-based systems, termed CRTEIL and CETRIZ, which allow gene switching in a noninvasive manner. Single transfection with pCRTEIL resulted in predominant expression of red fluorescence. Cotransfection with pCRTEIL and Cre-expression plasmid (pCAG/NCre caused switching from red to green fluorescence. Similarly, cotransfection with pCETRIZ and pCAG/NCre resulted in change of green to red fluorescence. These noninvasive systems will be useful in cell lineage analysis, since descendants of cells exhibiting newly activated gene expression can be continuously monitored in noninvasive fashion.

  5. Development of a recombinase polymerase amplification assay for Vibrio parahaemolyticus detection with an internal amplification control.

    Science.gov (United States)

    Yang, Huan-Lan; Wei, Shuang; Gooneratne, Ravi; Mutukumira, Anthony N; Ma, Xue-Jun; Tang, Shu-Ze; Wu, Xi-Yang

    2018-04-01

    A novel RPA-IAC assay using recombinase polymerase and an internal amplification control (IAC) for Vibrio parahaemolyticus detection was developed. Specific primers were designed based on the coding sequence for the toxR gene in V. parahaemolyticus. The recombinase polymerase amplification (RPA) reaction was conducted at a constant low temperature of 37 °C for 20 min. Assay specificity was validated by using 63 Vibrio strains and 10 non-Vibrio bacterial species. In addition, a competitive IAC was employed to avoid false-negative results, which co-amplified simultaneously with the target sequence. The sensitivity of the assay was determined as 3 × 10 3 CFU/mL, which is decidedly more sensitive than the established PCR method. This method was then used to test seafood samples that were collected from local markets. Seven out of 53 different raw seafoods were detected as V. parahaemolyticus-positive, which were consistent with those obtained using traditional culturing method and biochemical assay. This novel RPA-IAC assay provides a rapid, specific, sensitive, and more convenient detection method for V. parahaemolyticus.

  6. Rearrangement of Rag-1 recombinase gene in DNA-repair deficient/immunodeficient ``wasted`` mice

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, G.E.; Weaver, P.; Churchill, M.; Chang-Liu, C-M. [Argonne National Lab., IL (United States); Libertin, C.R. [Loyola Univ., Maywood, IL (United States)

    1992-11-01

    Mice recessive for the autosomal gene ``wasted`` (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (Rag-l/Rag-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed that in thymus tissue, a small Rag-I transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/{sm_bullet} mice, a two-fold increase in Rag-1 mRNA was evident in thymus tissue. Rag-2 mRNA could only be detected in thymus tissue from wst/{sm_bullet} and not from wst/wst or parental control BCF, mice. Southern blots revealed a rearrangement or deletion within the Rag-1 gene of affected wasted mice that was not evident in known strain-specific parental or littermate controls. These results support the idea that the Rag-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

  7. Generation of an inducible colon-specific Cre enzyme mouse line for colon cancer research.

    Science.gov (United States)

    Tetteh, Paul W; Kretzschmar, Kai; Begthel, Harry; van den Born, Maaike; Korving, Jeroen; Morsink, Folkert; Farin, Henner; van Es, Johan H; Offerhaus, G Johan A; Clevers, Hans

    2016-10-18

    Current mouse models for colorectal cancer often differ significantly from human colon cancer, being largely restricted to the small intestine. Here, we aim to develop a colon-specific inducible mouse model that can faithfully recapitulate human colon cancer initiation and progression. Carbonic anhydrase I (Car1) is a gene expressed uniquely in colonic epithelial cells. We generated a colon-specific inducible Car1 CreER knock-in (KI) mouse with broad Cre activity in epithelial cells of the proximal colon and cecum. Deletion of the tumor suppressor gene Apc using the Car1 CreER KI caused tumor formation in the cecum but did not yield adenomas in the proximal colon. Mutation of both Apc and Kras yielded microadenomas in both the cecum and the proximal colon, which progressed to macroadenomas with significant morbidity. Aggressive carcinomas with some invasion into lymph nodes developed upon combined induction of oncogenic mutations of Apc, Kras, p53, and Smad4 Importantly, no adenomas were observed in the small intestine. Additionally, we observed tumors from differentiated Car1-expressing cells with Apc/Kras mutations, suggesting that a top-down model of intestinal tumorigenesis can occur with multiple mutations. Our results establish the Car1 CreER KI as a valuable mouse model to study colon-specific tumorigenesis and metastasis as well as cancer-cell-of-origin questions.

  8. Down-regulation of Irf8 by Lyz2-cre/loxP accelerates osteoclast differentiation in vitro.

    Science.gov (United States)

    Saito, Emi; Suzuki, Dai; Kurotaki, Daisuke; Mochizuki, Ayako; Manome, Yoko; Suzawa, Tetsuo; Toyoshima, Yoichi; Ichikawa, Takahiro; Funatsu, Takahiro; Inoue, Tomio; Takami, Masamichi; Tamura, Tomohiko; Inagaki, Katsunori; Kamijo, Ryutaro

    2017-06-01

    Interferon regulatory factor 8 (Irf8) is a transcription factor that negatively regulates osteoclast differentiation and Irf8 global knockout (Irf8 -/- ) mice have been shown to have reduced bone volume resulting from increased osteoclast numbers. However, detailed analysis of the functions of Irf8 in osteoclast precursors with a monocyte/macrophage linage is difficult, because the population and properties of hematopoietic cells in Irf8 -/- mice are severely altered. Therefore, to clearly elucidate the functions of Irf8 during osteoclastogenesis, we established myeloid cell-specific Irf8 conditional knockout (Irf8 fl/fl ;Lyz2 cre/+ ) mice. We found that trabecular bone volume in the Irf8 fl/fl ;Lyz2 cre/+ mice was not significantly affected, while exposure to M-CSF and RANKL significantly increased TRAP activity in vitro in osteoclasts that underwent osteoclastogenesis from bone marrow-derived macrophages (BMMs) induced from bone marrow cells (BMCs) of those mice by addition of M-CSF. Our results also showed that expression of Irf8 mRNA and protein in BMMs obtained from Irf8 fl/fl ;Lyz2 cre/+ mice and cultured with M-CSF was reduced. These findings predicted that Lyz2/Lyz2-cre expression is induced when BMCs differentiate into BMMs in cultures with M-CSF. In osteoclast differentiation cultures, Lyz2 was gradually increased by M-CSF during the first 3 days of culture, then rapidly decreased by the addition of RANKL with M-CSF during the next 3 days. Furthermore, BMCs differentiated into osteoclasts while maintaining a low level of Lyz2 expression when cultured simultaneously with both M-CSF and RANKL from the initiation of culture. These findings suggest that Lyz2-cre expression is induced along with differentiation to BMMs by BMCs obtained from Irf8 fl/fl ;Lyz2 cre/+ mice and cultured with M-CSF. In addition, Irf8 was down-regulated by activation of the cre/loxP recombination system in BMMs and osteoclastogenesis was accelerated. Based on our results, we propose

  9. Cloning-free genome engineering in Sinorhizobium meliloti advances applications of Cre/loxP site-specific recombination.

    Science.gov (United States)

    Döhlemann, Johannes; Brennecke, Meike; Becker, Anke

    2016-09-10

    The soil-dwelling α-proteobacterium Sinorhizobium meliloti serves as model for studies of symbiotic nitrogen fixation, a highly important process in sustainable agriculture. Here, we report advancements of the genetic toolbox accelerating genome editing in S. meliloti. The hsdMSR operon encodes a type-I restriction-modification (R-M) system. Transformation of S. meliloti is counteracted by the restriction endonuclease HsdR degrading DNA which lacks the appropriate methylation pattern. We provide a stable S. meliloti hsdR deletion mutant showing enhanced transformation with Escherichia coli-derived plasmid DNA and demonstrate that using an E. coli plasmid donor, expressing S. meliloti methyl transferase genes, is an alternative strategy of increasing the transformation efficiency of S. meliloti. Furthermore, we devise a novel cloning-free genome editing (CFGE) method for S. meliloti, Agrobacterium tumefaciens and Xanthomonas campestris, and demonstrate the applicability of this method for intricate applications of the Cre/lox recombination system in S. meliloti. An enhanced Cre/lox system, allowing for serial deletions of large genomic regions, was established. An assay of lox spacer mutants identified a set of lox sites mediating specific recombination. The availability of several non-promiscuous Cre recognition sites enables simultaneous specific Cre/lox recombination events. CFGE combined with Cre/lox recombination is put forward as powerful approach for targeted genome editing, involving serial steps of manipulation to expedite the genetic accessibility of S. meliloti as chassis. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Adipocyte-specific protein tyrosine phosphatase 1B deletion increases lipogenesis, adipocyte cell size and is a minor regulator of glucose homeostasis.

    Directory of Open Access Journals (Sweden)

    Carl Owen

    Full Text Available Protein tyrosine phosphatase 1B (PTP1B, a key negative regulator of leptin and insulin signaling, is positively correlated with adiposity and contributes to insulin resistance. Global PTP1B deletion improves diet-induced obesity and glucose homeostasis via enhanced leptin signaling in the brain and increased insulin signaling in liver and muscle. However, the role of PTP1B in adipocytes is unclear, with studies demonstrating beneficial, detrimental or no effect(s of adipose-PTP1B-deficiency on body mass and insulin resistance. To definitively establish the role of adipocyte-PTP1B in body mass regulation and glucose homeostasis, adipocyte-specific-PTP1B knockout mice (adip-crePTP1B(-/- were generated using the adiponectin-promoter to drive Cre-recombinase expression. Chow-fed adip-crePTP1B(-/- mice display enlarged adipocytes, despite having similar body weight/adiposity and glucose homeostasis compared to controls. High-fat diet (HFD-fed adip-crePTP1B(-/- mice display no differences in body weight/adiposity but exhibit larger adipocytes, increased circulating glucose and leptin levels, reduced leptin sensitivity and increased basal lipogenesis compared to controls. This is associated with decreased insulin receptor (IR and Akt/PKB phosphorylation, increased lipogenic gene expression and increased hypoxia-induced factor-1-alpha (Hif-1α expression. Adipocyte-specific PTP1B deletion does not beneficially manipulate signaling pathways regulating glucose homeostasis, lipid metabolism or adipokine secretion in adipocytes. Moreover, PTP1B does not appear to be the major negative regulator of the IR in adipocytes.

  11. Extracellular signal-regulated kinase 1 and 2 are not required for GnRH neuron development and normal female reproductive axis function in mice.

    Science.gov (United States)

    Wierman, Margaret E; Xu, Mei; Pierce, A; Bliesner, B; Bliss, S P; Roberson, M S

    2012-01-01

    Selective deletion of extracellular signal-regulated kinase (ERK) 1 and ERK2 in the pituitary gonadotrope and ovarian granulosa cells disrupts female reproductive axis function. Thus, we asked if ERK1 and ERK2 are critical for GnRH neuron ontogeny or the central control of female reproductive function. GnRH-Cre-recombinase (Cre+) expressing mice were crossed with mice with a global deletion of ERK1 and a floxed ERK2 allele (Erk1-/Erk2fl/fl) to selectively delete ERK2 in GnRH neurons. Cre-recombinase mRNA was selectively expressed in the brain of Cre+ mice. GnRH neuron number and location were determined during embryogenesis and in the adult. GnRH neuron counts at E15 did not differ between experimental and control groups (1,198 ± 65 and 1,160 ± 80 respectively, p = NS). In adults, numbers of GnRH neurons in the GnRHCre+Erk1-/Erk2- mice (741 ± 157) were similar to those in controls (756 ± 7), without alteration in their distribution across the forebrain. ERK1 and 2 deficiency did not alter the timing of vaginal opening, age at first estrus, or estrous cyclicity. Although ERK1 and 2 are components of a dominant signaling pathway in GnRH neuronal cells that modulates survival and control of GnRH gene expression, other signaling pathways compensate for their deletion in vivo to allow GnRH neuron survival and targeting and normal onset of female sexual maturation and reproductive function. In contrast to effects at the pituitary and the ovary, ERK1 and ERK2 are dispensable at the level of the GnRH neuron. Copyright © 2011 S. Karger AG, Basel.

  12. Transient Cnp expression by early progenitors causes Cre-Lox-based reporter lines to map profoundly different fates.

    Science.gov (United States)

    Tognatta, Reshmi; Sun, Wenjing; Goebbels, Sandra; Nave, Klaus-Armin; Nishiyama, Akiko; Schoch, Susanne; Dimou, Leda; Dietrich, Dirk

    2017-02-01

    NG2 expressing oligodendroglial precursor cells are ubiquitous in the central nervous system and the only cell type cycling throughout life. Previous fate mapping studies have remained inconsistent regarding the question whether NG2 cells are capable of generating certain types of neurons. Here, we use CNP-Cre mice to map the fate of a sub-population of NG2 cells assumed to be close to differentiation. When crossing these mice with the ROSA26/YFP Cre-reporter line we discovered large numbers of reporter-expressing pyramidal neurons in the piriform and dorsal cortex. In contrast, when using Z/EG reporter mice to track the fate of Cnp-expressing NG2 cells only oligodendroglial cells were found reporter positive. Using BrdU-based birth dating protocols and inducible NG2CreER:ROSA26/YFP mice we show that YFP positive neurons are generated from radial glial cells and that these radial glial cells display temporary and low level activity of certain oligodendroglial genes sufficient to recombine the Cre-inducible reporter gene in ROSA26/YFP but not in Z/EG mice. Taken together, we did not obtain evidence for generation of neurons from NG2 cells. Our results suggest that with an appropriate reporter system Cnp activity can be used to define a proliferative subpopulation of NG2 cells committed to generate oligodendrocytes. However, the strikingly different results obtained from ROSA26/YFP versus Z/EG mice demonstrate that the choice of Cre-reporter line can be of crucial importance for fate mapping studies and other applications of the Cre-lox technology. GLIA 2017;65:342-359. © 2016 Wiley Periodicals, Inc.

  13. Size does matter: Cre-mediated somatic deletion efficiency depends on the distance between the target lox-sites

    NARCIS (Netherlands)

    Coppoolse, E.R.; Vroomen, de M.J.; Gennip, van F.; Hersmus, B.J.M.; Haaren, van M.J.

    2005-01-01

    Cre/lox recombination in vivo has become an important tool to induce chromosomal rearrangements like deletions. Using a combination of Ds transposition and Cre/lox recombination in two independent experiments on chromosomes 6 and 7 of tomato, two sets of somatic deletions up to a size of 200 kb were

  14. Flavonoids and Auxin Transport Inhibitors Rescue Symbiotic Nodulation in the Medicago truncatula Cytokinin Perception Mutant cre1

    Science.gov (United States)

    Ng, Jason Liang Pin; Hassan, Samira; Truong, Thy T.; Hocart, Charles H.; Laffont, Carole; Frugier, Florian; Mathesius, Ulrike

    2015-01-01

    Initiation of symbiotic nodules in legumes requires cytokinin signaling, but its mechanism of action is largely unknown. Here, we tested whether the failure to initiate nodules in the Medicago truncatula cytokinin perception mutant cre1 (cytokinin response1) is due to its altered ability to regulate auxin transport, auxin accumulation, and induction of flavonoids. We found that in the cre1 mutant, symbiotic rhizobia cannot locally alter acro- and basipetal auxin transport during nodule initiation and that these mutants show reduced auxin (indole-3-acetic acid) accumulation and auxin responses compared with the wild type. Quantification of flavonoids, which can act as endogenous auxin transport inhibitors, showed a deficiency in the induction of free naringenin, isoliquiritigenin, quercetin, and hesperetin in cre1 roots compared with wild-type roots 24 h after inoculation with rhizobia. Coinoculation of roots with rhizobia and the flavonoids naringenin, isoliquiritigenin, and kaempferol, or with the synthetic auxin transport inhibitor 2,3,5,-triiodobenzoic acid, rescued nodulation efficiency in cre1 mutants and allowed auxin transport control in response to rhizobia. Our results suggest that CRE1-dependent cytokinin signaling leads to nodule initiation through the regulation of flavonoid accumulation required for local alteration of polar auxin transport and subsequent auxin accumulation in cortical cells during the early stages of nodulation. PMID:26253705

  15. CRE answer to the European Commission public consultation on the new electricity market design

    International Nuclear Information System (INIS)

    Ladoucette, Philippe de

    2015-01-01

    On July 15, 2015, the European Commission launched a public consultation on the new Electricity Market Design. All National Regulatory Authorities (NRAs), and CRE in particular, contributed to the joint ACER-CEER response to the consultation. CRE supports this joint response, and further develops some topics in this document, building on its particular experience in the implementation of the internal energy market: implementation of the network codes, in particular those regarding the markets, development of demand-side flexibility, development of interconnections, and alignment of fragmented balancing markets

  16. Rearrangement of RAG-1 recombinase gene in DNA-repair deficient ``wasted`` mice

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, G.E.; Libertin, C.R.; Weaver, P. [Loyola Univ., Chicago, IL (United States); Churchill, M.; Chang-Liu, C.M. [Argonne National Lab., IL (United States)

    1993-11-01

    Mice recessive for the autosomal gene ``wasted`` wst display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (RAG-l/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed expression of RAG-1 mRNA in spinal cord (but not brain) of control mice; no expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/{center_dot}mice). In thymus tissue, a small RAG-1 transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/{center_dot}mice, a two-fold increase in RAG-1 mRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/{center_dot} and not from wst/wst or parental control BCF{sub 1} mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

  17. Structural and functional characterization of the coxsackievirus B3 CRE(2C): role of CRE(2C) in negative- and positive-strand RNA synthesis.

    NARCIS (Netherlands)

    Ooij, M.J.M. van; Vogt, D.A.; Paul, A.; Castro, C.; Kuijpers, J.M.; Kuppeveld, F.J.M. van; Cameron, C.E.; Wimmer, E.; Andino, R.; Melchers, W.J.G.

    2006-01-01

    A stem-loop element located within the 2C-coding region of the coxsackievirus B3 (CVB3) genome has been proposed to function as a cis-acting replication element (CRE). It is shown here that disruption of this structure indeed interfered with viral RNA replication in vivo and abolished uridylylation

  18. Generation and characterization of PDGFRα-GFPCreERT2 knock-In mouse line.

    Science.gov (United States)

    Miwa, Hiroyuki; Era, Takumi

    2015-05-01

    Platelet-derived growth factor (PDGF) and its receptor play an important role in embryogenesis. PDGF receptor α (PDGFRα) is expressed specifically in the embryonic day 7.5 (E7.5) mesoderm and in the E9.5 neural crest among other tissues. PDGFRα-expressing cells and their descendants are involved in the formation of various tissues. To trace PDGFRα-expressing cells in vivo, we generated a knock-in mouse line that expressed a fusion protein of green fluorescent protein (GFP), Cre recombinase (Cre), and mutated estrogen receptor ligand-binding domain (ERT2) under the control of the PDGFRα promoter. In these mice, Cre activity in PDGFRα-expressing cells could be induced by tamoxifen treatment. Taken together, our results suggest that the knock-in mouse line generated here could be useful for studying PDGFRα-expressing cells and their descendants in vivo at various stages of development. © 2015 Wiley Periodicals, Inc.

  19. A Novel Reporter Rat Strain That Conditionally Expresses the Bright Red Fluorescent Protein tdTomato.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Igarashi

    Full Text Available Despite the strength of the Cre/loxP recombination system in animal models, its application in rats trails that in mice because of the lack of relevant reporter strains. Here, we generated a floxed STOP tdTomato rat that conditionally expresses a red fluorescent protein variant (tdTomato in the presence of exogenous Cre recombinase. The tdTomato signal vividly visualizes neurons including their projection fibers and spines without any histological enhancement. In addition, a transgenic rat line (FLAME that ubiquitously expresses tdTomato was successfully established by injecting intracytoplasmic Cre mRNA into fertilized ova. Our rat reporter system will facilitate connectome studies as well as the visualization of the fine structures of genetically identified cells for long periods both in vivo and ex vivo. Furthermore, FLAME is an ideal model for organ transplantation research owing to improved traceability of cells/tissues.

  20. Real Time Visualization and Manipulation of the Metastatic Trajectory ofBreast Cancer Cell

    Science.gov (United States)

    2017-09-01

    AWARD NUMBER: W81XWH-13-1-0173 TITLE: Real-Time Visualization and Manipulation of the Metastatic Trajectory of Breast Cancer Cells ...of this work was to engineer breast cancer cells to irreversibly alter the genome of nearby cells through exosomal transfer of Cre recombinase from...the cancer cells to surrounding cells . Our goal was to use this study to activate green fluorescent protein in the host reporter cells in the

  1. OMNeT++ BENZETİM ARACI KULLANILARAK MOBİL IPV6 KATMAN-2 HÜCRE GEÇİŞİ BAŞARIMININ ANALİZİ

    Directory of Open Access Journals (Sweden)

    Gürcan ÇETİN

    2015-04-01

    Full Text Available Bir Mobil Düğüm (Mobile Node - MN aktif iletişimi sürdürürken pürüzsüz bir hücre geçişi sağlamak Mobil IP sürüm 6 (MIPv6 için en önemli etkenlerden birisidir. Pürüzsüz bir hücre geçişi, MIPv6 protokolünde açıkça tanımlanan hareketliliğin tespit edilmesi, yeni bir adresin yapılandırılması ve bağlama güncellemesi işlemleri sırasındaki gecikme sürelerinin azaltılması ya da sonlandırılması ile gerçekleştirilebilir. Ancak, MIPv6 hücre geçişi süreci Katman2 (Layer2- L2 ve Katman-3 (Layer 3 – L3 işlemleri nedeniyle oldukça karmaşıktır ve bu dezavantaj özellikle makro hareketlilikte ve gerçek zamanlı iletişimde performansta önemli derecede azalmaya neden olur. L3 hücre geçişi MIPv6 hücre geçişinin en önemli faktörüdür çünkü toplam hücre geçişi gecikmesinin büyük bir bölümü bu aşamada meydana gelir. Diğer taraftan, L2 hücre geçişişi L3 hücre geçişine göre çok daha az kayıp ile sonuçlanır. Ancak, L2 hücre geçişi üzerine yapılan çalışmalar da literatürde önemli yer tutmaktadır. Çünkü L2 hücre geçişi sırasında gerçekleşen olaylar L3 hücre geçişini önceden tetikleyebilmektedir. Bu sayede, pürüzsüz hücre geçişi teknikleri bu şekilde gerçekleştirilmektedir. L2 yaklaşımı L3 tabanlı çözümlere göre çok daha hızlıdır. Buna rağmen bu yöntemlerde L2 hücre geçişi gecikmesi kadar sınırlıdırlar. Bu makalede, biz MIPv6 hücre geçişindeki L2 gecikmelerini OMNeT++ benzetim ortamını kullanarak analiz ettik. Bu analizler, L2 hücre geçişi gecikmelerinin bileşenlerini ayrı ayrı gösterecektir

  2. Unexpected Cartilage Phenotype in CD4-Cre-Conditional SOS-Deficient Mice.

    Science.gov (United States)

    Guittard, Geoffrey; Gallardo, Devorah L; Li, Wenmei; Melis, Nicolas; Lui, Julian C; Kortum, Robert L; Shakarishvili, Nicholas G; Huh, Sunmee; Baron, Jeffrey; Weigert, Roberto; Kramer, Joshua A; Samelson, Lawrence E; Sommers, Connie L

    2017-01-01

    RAS signaling is central to many cellular processes and SOS proteins promote RAS activation. To investigate the role of SOS proteins in T cell biology, we crossed Sos1 f/f Sos2 -/- mice to CD4-Cre transgenic mice. We previously reported an effect of these mutations on T cell signaling and T cell migration. Unexpectedly, we observed nodules on the joints of greater than 90% of these mutant mice at 5 months of age, especially on the carpal joints. As the mice aged further, some also displayed joint stiffness, hind limb paralysis, and lameness. Histological analysis indicated that the abnormal growth in joints originated from dysplastic chondrocytes. Second harmonic generation imaging of the carpal nodules revealed that nodules were encased by rich collagen fibrous networks. Nodules formed in mice also deficient in RAG2, indicating that conventional T cells, which undergo rearrangement of the T cell antigen receptor, are not required for this phenotype. CD4-Cre expression in a subset of cells, either immune lineage cells (e.g., non-conventional T cells) or non-immune lineage cells (e.g., chondrocytes) likely mediates the dramatic phenotype observed in this study. Disruptions of genes in the RAS signaling pathway are especially likely to cause this phenotype. These results also serve as a cautionary tale to those intending to use CD4-Cre transgenic mice to specifically delete genes in conventional T cells.

  3. α-Fetoprotein promoter-driven Cre/LoxP-switched RNA interference for hepatocellular carcinoma tissue-specific target therapy.

    Directory of Open Access Journals (Sweden)

    Yuan-Fei Peng

    Full Text Available RNA interference (RNAi has recently emerged as a potential treatment modality for hepatocellular carcinoma (HCC therapy, but the lack of cellular targets and sustained efficacy limits its application. The purpose of this study is to develop an HCC tissue-specific RNAi system and investigate its possibility for HCC treatment.Two different HCC-specific RNAi systems in which therapeutic miRNA or shRNA against target gene (Beclin 1 was directly or indirectly driven by alpha-fetoprotein promoter (AFP-miRNA and AFP-Cre/LoxP-shRNA were constructed. Human HCC cell lines (HepG2, Hep3B and HCCLM3 and non-HCC cell lines (L-02, Hela and SW1116 were infected with the systems. The effectiveness and tissue-specificity of the systems were examined by Q-PCR and western blot analysis. The efficacy of the systems was further tested in mouse model of HCC by intravenous or intratumoral administration. The feasibility of the system for HCC treatment was evaluated by applying the system as adjuvant therapy to enhance sorafenib treatment. An AFP-Cre/LoxP-shRNA system targeting Atg5 gene (AFP-Cre/LoxP-shRNA-Atg5 was constructed and its efficacy in sensitizing HCC cells (MHCC97L/PLC to sorafenib treatment was examined by apoptosis assay in vitro and tumorigenesis assay in vivo.The AFP-miRNA system could silence target gene (Beclin 1 but required a high titer which was lethal to target cells. The AFP-Cre/LoxP-shRNA system could efficiently knockdown target gene while maintain high HCC specificity. Intratumoral injection of the AFP-Cre/LoxP-shRNA system could efficiently silence target gene (Beclin 1 in vivo while intravenous administration could not. The AFP-Cre/LoxP-shRNA system target Atg5 gene could significantly sensitize MHCC97L/PLC cells to sorafenib-induced apoptosis in vitro and tumor growth suppression in vivo.An efficient HCC tissue-specific RNAi system (AFP-Cre/LoxP-shRNA was successfully established. The system provides a usable tool for HCC-specific RNAi

  4. Quantitative measures of CRE and its link with organizational performance

    NARCIS (Netherlands)

    Appel - Meulenbroek, H.A.J.A.

    2007-01-01

    For CREM (Corporate Real Estate Management) to be able to deliver added value to its client organisation, it has to know 1) which CRE aspects influence its employees, processes, machinery, visitors, etc, 2) how these aspects influence performance and 3) how to measure and manage them. Analysis of

  5. Use of Cre/loxP recombination to swap cell binding motifs on the adenoviral capsid protein IX

    International Nuclear Information System (INIS)

    Poulin, Kathy L.; Tong, Grace; Vorobyova, Olga; Pool, Madeline; Kothary, Rashmi; Parks, Robin J.

    2011-01-01

    We used Cre/loxP recombination to swap targeting ligands present on the adenoviral capsid protein IX (pIX). A loxP-flanked sequence encoding poly-lysine (pK-binds heparan sulfate proteoglycans) was engineered onto the 3'-terminus of pIX, and the resulting fusion protein allowed for routine virus propagation. Growth of this virus on Cre-expressing cells removed the pK coding sequence, generating virus that could only infect through alternative ligands, such as a tyrosine kinase receptor A (TrkA)-binding motif engineered into the capsid fibre protein for enhanced infection of neuronal cells. We used a similar approach to swap the pK motif on pIX for a sequence encoding a single-domain antibody directed towards CD66c for targeted infection of cancer cells; Cre-mediated removal of the pK-coding sequence simultaneously placed the single-domain antibody coding sequence in frame with pIX. Thus, we have developed a simple method to propagate virus lacking native viral tropism but containing cell-specific binding ligands. - Highlights: → We describe a method to grow virus lacking native tropism but containing novel cell-binding ligands. → Cre/loxP recombination was used to modify the adenovirus genome. → A targeting ligand present on capsid protein IX was removed or replaced using recombination. → Cre-loxP was also used to 'swap' the identity of the targeting ligand present on pIX.

  6. Molecular Basis for Enhancement of the Meiotic DMCI Recombinase by RAD51AP1

    Energy Technology Data Exchange (ETDEWEB)

    Dray, Eloise; Dunlop, Myun Hwa; Kauppi, Liisa; San Filippo, Joseph San; Wiese, Claudia; Tsai, Miaw-Sheue; Begovic, Sead; Schild, David; Jasin, Maria; Keeney, Scott; Sung, Patrick

    2010-11-05

    Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 Associated Protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional co-operation is dependent on complex formation between DMC1 and RAD51AP1, and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci co-localize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.

  7. Development of the recombinase-based in vivo expression technology in Streptococcus thermophilus and validation using the lactose operon promoter

    NARCIS (Netherlands)

    Junjua, M.; Galia, W.; Gaci, N.; Uriot, O.; Genay, M.; Bachmann, H.; Kleerebezem, M.; Dary, A.; Roussel, Y.

    2014-01-01


    Aims

    To construct and validate the recombinase-based in vivo expression technology (R-IVET) tool in Streptococcus thermophilus (ST).

    Methods and Results

    The R-IVET system we constructed in the LMD-9 strain includes the plasmid pULNcreB allowing transcriptional fusion

  8. Skeletal muscle gene expression after myostatin knockout in mature mice Address for reprint requests and other correspondence: S. Welle, Univ. of Rochester Medical Center, 601 Elmwood Ave., Box 693, Rochester, NY 14642 (e-mail: ).

    OpenAIRE

    Welle, Stephen; Cardillo, Andrew; Zanche, Michelle; Tawil, Rabi

    2009-01-01

    There is much interest in developing anti-myostatin agents to reverse or prevent muscle atrophy in adults, so it is important to characterize the effects of reducing myostatin activity after normal muscle development. For assessment of the effect of loss of myostatin signaling on gene expression in muscle, RNA from mice with postdevelopmental myostatin knockout was analyzed with oligonucleotide microarrays. Myostatin was undetectable in muscle within 2 wk after Cre recombinase activation in 4...

  9. High burden of Carbapenem-resistant Enterobacteriaceae (CRE) fecal carriage at a teaching hospital: cost-effectiveness of screening in low-resource setting.

    Science.gov (United States)

    Zaidah, Abdul Rahman; Mohammad, Nurul Izzah; Suraiya, Siti; Harun, Azian

    2017-01-01

    Infections by multidrug-resistant gram-negative bacteria (MDR-GNB) have been continuously growing and pose challenge to health institution globally. Carbapenem-resistant Enterobacteriacea (CRE) was identified as one of the MDR-GNB which has limited treatment options and higher mortality compared to those of sensitive strains. We report an increased burden of CRE fecal carriage at a hospital in the North-eastern region of Malaysia. A retrospective descriptive study from August 2013 to December 2015 was conducted in the Medical Microbiology & Parasitology laboratory of Hospital Universiti Sains Malaysia, which is a tertiary teaching hospital with more than 700 beds. This hospital treats patients with various medical and surgical conditions. Suspected CRE from any clinical specimens received by the laboratory was identified and confirmed using standard protocols. Polymerase chain reaction (PCR) assay was performed to determine the genotype. Altogether, 8306 Enterobacteriaceae was isolated from various clinical specimens during the study period and 477/8306 (5.74%) were CRE. Majority of the isolated CRE were Klebsiella [408/477, (85.5%)], of which Klebsiella pneumoniae was the predominant species, 388/408 (95%). CRE were mainly isolated from rectal swab (screening), 235/477 (49.3%); urine, 76/477 (15.9%); blood, 46/477 (9.6%) and about 7.1% from tracheal aspirate. One hundred and thirty-six isolates were subjected to genotype determination and., 112/136 (82.4%) showed positive detection of New Delhi metallo-β-lactamase 1 (NDM-1) gene ( bla NDM1 ). The study noted a high numbers of CRE isolated especially from rectal swabs. Active screening results in significant cost pressures and therefore should be revisited and revised, especially in low resource settings.

  10. Agreement of quadratic and CRE models in predicting the late effects of continuous low dose-rate radiotherapy; and reply

    International Nuclear Information System (INIS)

    O'Donoghue, J.A.

    1986-01-01

    These letters discuss the problems associated with the fact that the normal tissue isoeffect formulae based on the Ellis equation (1969) do not correctly account for the late-occurring effects of fractionated radiotherapy, and with the extension of the linear quadratic model to include continuous low dose-rate radiotherapy with constant or decaying sources by R.G. Dale (1985). J.A. O'Donoghue points out that the 'late effects' and CRE curves correspond closely, whilst the 'acute effects; and CRE curves are in obvious disagreement. For continuous low-dose-rate radiotherapy, the CRE and late effects quadratic model are in agreement. Useful bibliography. (U.K.)

  11. Generation of mice harbouring a conditional loss-of-function allele of Gata6

    Directory of Open Access Journals (Sweden)

    Duncan Stephen A

    2006-04-01

    Full Text Available Abstract The zinc finger transcription factor GATA6 is believed to have important roles in the development of several organs including the liver, gastrointestinal tract and heart. However, analyses of the contribution of GATA6 toward organogenesis have been hampered because Gata6-/- mice fail to develop beyond gastrulation due to defects in extraembryonic endoderm function. We have therefore generated a mouse line harbouring a conditional loss-of-function allele of Gata6 using Cre/loxP technology. LoxP elements were introduced into introns flanking exon 2 of the Gata6 gene by homologous recombination in ES cells. Mice containing this altered allele were bred to homozygosity and were found to be viable and fertile. To assess the functional integrity of the loxP sites and to confirm that we had generated a Gata6 loss-of-function allele, we bred Gata6 'floxed' mice to EIIa-Cre mice in which Cre is ubiquitously expressed, and to Villin-Cre mice that express Cre in the epithelial cells of the intestine. We conclude that we have generated a line of mice in which GATA6 activity can be ablated in a cell type specific manner by expression of Cre recombinase. This line of mice can be used to establish the role of GATA6 in regulating embryonic development and various aspects of mammalian physiology.

  12. Rearrangement of Rag-1 recombinase gene in DNA-repair deficient/immunodeficient wasted'' mice

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, G.E.; Weaver, P.; Churchill, M.; Chang-Liu, C-M. (Argonne National Lab., IL (United States)); Libertin, C.R. (Loyola Univ., Maywood, IL (United States))

    1992-01-01

    Mice recessive for the autosomal gene wasted'' (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (Rag-l/Rag-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed that in thymus tissue, a small Rag-I transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/[sm bullet] mice, a two-fold increase in Rag-1 mRNA was evident in thymus tissue. Rag-2 mRNA could only be detected in thymus tissue from wst/[sm bullet] and not from wst/wst or parental control BCF, mice. Southern blots revealed a rearrangement or deletion within the Rag-1 gene of affected wasted mice that was not evident in known strain-specific parental or littermate controls. These results support the idea that the Rag-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

  13. Healthcare Antibiotic Resistance Prevalence - DC (HARP-DC): A Regional Prevalence Assessment of Carbapenem-Resistant Enterobacteriaceae (CRE) in Healthcare Facilities in Washington, District of Columbia.

    Science.gov (United States)

    Reuben, Jacqueline; Donegan, Nancy; Wortmann, Glenn; DeBiasi, Roberta; Song, Xiaoyan; Kumar, Princy; McFadden, Mary; Clagon, Sylvia; Mirdamadi, Janet; White, Diane; Harris, Jo Ellen; Browne, Angella; Hooker, Jane; Yochelson, Michael; Walker, Milena; Little, Gary; Jernigan, Gail; Hansen, Kathleen; Dockery, Brenda; Sinatro, Brendan; Blaylock, Morris; Harmon, Kimary; Iyengar, Preetha; Wagner, Trevor; Nelson, Jo Anne

    2017-08-01

    OBJECTIVE Carbapenem-resistant Enterobacteriaceae (CRE) are a significant clinical and public health concern. Understanding the distribution of CRE colonization and developing a coordinated approach are key components of control efforts. The prevalence of CRE in the District of Columbia is unknown. We sought to determine the CRE colonization prevalence within healthcare facilities (HCFs) in the District of Columbia using a collaborative, regional approach. DESIGN Point-prevalence study. SETTING This study included 16 HCFs in the District of Columbia: all 8 acute-care hospitals (ACHs), 5 of 19 skilled nursing facilities, 2 (both) long-term acute-care facilities, and 1 (the sole) inpatient rehabilitation facility. PATIENTS Inpatients on all units excluding psychiatry and obstetrics-gynecology. METHODS CRE identification was performed on perianal swab samples using real-time polymerase chain reaction, culture, and antimicrobial susceptibility testing (AST). Prevalence was calculated by facility and unit type as the number of patients with a positive result divided by the total number tested. Prevalence ratios were compared using the Poisson distribution. RESULTS Of 1,022 completed tests, 53 samples tested positive for CRE, yielding a prevalence of 5.2% (95% CI, 3.9%-6.8%). Of 726 tests from ACHs, 36 (5.0%; 95% CI, 3.5%-6.9%) were positive. Of 244 tests from long-term-care facilities, 17 (7.0%; 95% CI, 4.1%-11.2%) were positive. The relative prevalence ratios by facility type were 0.9 (95% CI, 0.5-1.5) and 1.5 (95% CI, 0.9-2.6), respectively. No CRE were identified from the inpatient rehabilitation facility. CONCLUSION A baseline CRE prevalence was established, revealing endemicity across healthcare settings in the District of Columbia. Our study establishes a framework for interfacility collaboration to reduce CRE transmission and infection. Infect Control Hosp Epidemiol 2017;38:921-929.

  14. High burden of Carbapenem-resistant Enterobacteriaceae (CRE fecal carriage at a teaching hospital: cost-effectiveness of screening in low-resource setting

    Directory of Open Access Journals (Sweden)

    Abdul Rahman Zaidah

    2017-05-01

    Full Text Available Abstract Background Infections by multidrug-resistant gram-negative bacteria (MDR-GNB have been continuously growing and pose challenge to health institution globally. Carbapenem-resistant Enterobacteriacea (CRE was identified as one of the MDR-GNB which has limited treatment options and higher mortality compared to those of sensitive strains. We report an increased burden of CRE fecal carriage at a hospital in the North-eastern region of Malaysia. Methods A retrospective descriptive study from August 2013 to December 2015 was conducted in the Medical Microbiology & Parasitology laboratory of Hospital Universiti Sains Malaysia, which is a tertiary teaching hospital with more than 700 beds. This hospital treats patients with various medical and surgical conditions. Suspected CRE from any clinical specimens received by the laboratory was identified and confirmed using standard protocols. Polymerase chain reaction (PCR assay was performed to determine the genotype. Results Altogether, 8306 Enterobacteriaceae was isolated from various clinical specimens during the study period and 477/8306 (5.74% were CRE. Majority of the isolated CRE were Klebsiella [408/477, (85.5%], of which Klebsiella pneumoniae was the predominant species, 388/408 (95%. CRE were mainly isolated from rectal swab (screening, 235/477 (49.3%; urine, 76/477 (15.9%; blood, 46/477 (9.6% and about 7.1% from tracheal aspirate. One hundred and thirty-six isolates were subjected to genotype determination and., 112/136 (82.4% showed positive detection of New Delhi metallo-β-lactamase 1 (NDM-1 gene (bla NDM1. Conclusion The study noted a high numbers of CRE isolated especially from rectal swabs. Active screening results in significant cost pressures and therefore should be revisited and revised, especially in low resource settings.

  15. Tracing notochord-derived cells using a Noto-cre mouse: implications for intervertebral disc development.

    Science.gov (United States)

    McCann, Matthew R; Tamplin, Owen J; Rossant, Janet; Séguin, Cheryle A

    2012-01-01

    Back pain related to intervertebral disc degeneration is the most common musculoskeletal problem, with a lifetime prevalence of 82%. The lack of effective treatment for this widespread problem is directly related to our limited understanding of disc development, maintenance and degeneration. The aim of this study was to determine the developmental origins of nucleus pulposus cells within the intervertebral disc using a novel notochord-specific Cre mouse. To trace the fate of notochordal cells within the intervertebral disc, we derived a notochord-specific Cre mouse line by targeting the homeobox gene Noto. Expression of this gene is restricted to the node and the posterior notochord during gastrulation [embryonic day 7.5 (E7.5)-E12.5]. The Noto-cre mice were crossed with a conditional lacZ reporter for visualization of notochord fate in whole-mount embryos. We performed lineage-tracing experiments to examine the contribution of the notochord to spinal development from E12.5 through to skeletally mature mice (9 months). Fate mapping studies demonstrated that, following elongation and formation of the primitive axial skeleton, the notochord gives rise to the nucleus pulposus in fully formed intervertebral discs. Cellular localization of β-galactosidase (encoded by lacZ) and cytokeratin-8 demonstrated that both notochordal cells and chondrocyte-like nucleus pulposus cells are derived from the embryonic notochord. These studies establish conclusively that notochordal cells act as embryonic precursors to all cells found within the nucleus pulposus of the mature intervertebral disc. This suggests that notochordal cells might serve as tissue-specific progenitor cells within the disc and establishes the Noto-cre mouse as a unique tool to interrogate the contribution of notochordal cells to both intervertebral disc development and disc degeneration.

  16. Rapid In Vivo Validation of Tumor Suppressor Gene Function in Prostate Cancer Progression

    Science.gov (United States)

    2016-07-01

    identification of the best sgRNA sequences and accelerated our ability to move to the in vivo studies proposed in Aim2. Our goal was to use CRISPR / Cas ...and to initiate prostate cancer in the mouse after injection of lentiviral particles expressing CRISPR / Cas components and Cre recombinase. Our initial...in vivo Our goal was to use CRISPR / Cas lentiviral transduction of the adult prostate to inactivate p53 or Rb. We aimed to recapitulate the effects of

  17. Microenvironment-Programmed Metastatic Prostate Cancer Stem Cells (mPCSCs)

    Science.gov (United States)

    2015-10-01

    with meta- static prostate cancer and serum prostate- specific antigen levels of < 10 ng/mL. BJU Int. 2005; 96:303–307. 59. Davis JN, Wojno KJ...renewal in vivo. As an example, in a recent study, prostate- specific antigen (PSA)-positive (PSAþ) and PSA/lo human prostate cancer cells were...In addition, transgene inser- tion of Cre recombinase under the control of a specific pro - moter may alter the function of the endogenous locus via

  18. Relation between extent of myostatin depletion and muscle growth in mature mice

    OpenAIRE

    Welle, Stephen; Burgess, Kerri; Thornton, Charles A.; Tawil, Rabi

    2009-01-01

    Myostatin is a negative regulator of muscle growth and fiber size. Changes in myostatin expression might contribute to changes in muscle mass associated with various conditions, and reducing the amount of active myostatin is a potential strategy for preventing or reversing muscle atrophy. The present study was done to determine the extent to which myostatin levels must decline to induce growth of mature muscles. Myostatin expression was reduced by activating Cre recombinase in adult mice with...

  19. Permanent Genetic Access to Transiently Active Neurons via TRAP: Targeted Recombination in Active Populations

    OpenAIRE

    Guenthner, Casey J.; Miyamichi, Kazunari; Yang, Helen H.; Heller, H. Craig; Luo, Liqun

    2013-01-01

    Targeting genetically encoded tools for neural circuit dissection to relevant cellular populations is a major challenge in neurobiology. We developed a new approach, Targeted Recombination in Active Populations (TRAP), to obtain genetic access to neurons that were activated by defined stimuli. This method utilizes mice in which the tamoxifen-dependent recombinase CreERT2 is expressed in an activity-dependent manner from the loci of the immediate early genes Arc and Fos. Active cells that expr...

  20. Improved α-Amylase Production by Dephosphorylation Mutation of CreD, an Arrestin-Like Protein Required for Glucose-Induced Endocytosis of Maltose Permease and Carbon Catabolite Derepression in Aspergillus oryzae.

    Science.gov (United States)

    Tanaka, Mizuki; Hiramoto, Tetsuya; Tada, Hinako; Shintani, Takahiro; Gomi, Katsuya

    2017-07-01

    Aspergillus oryzae produces copious amount of amylolytic enzymes, and MalP, a major maltose permease, is required for the expression of amylase-encoding genes. The expression of these genes is strongly repressed by carbon catabolite repression (CCR) in the presence of glucose. MalP is transported from the plasma membrane to the vacuole by endocytosis, which requires the homolog of E6-AP carboxyl terminus ubiquitin ligase HulA, an ortholog of yeast Rsp5. In yeast, arrestin-like proteins mediate endocytosis as adaptors of Rsp5 and transporters. In the present study, we examined the involvement of CreD, an arrestin-like protein, in glucose-induced MalP endocytosis and CCR of amylase-encoding genes. Deletion of creD inhibited the glucose-induced endocytosis of MalP, and CreD showed physical interaction with HulA. Phosphorylation of CreD was detected by Western blotting, and two serine residues were determined as the putative phosphorylation sites. However, the phosphorylation state of the serine residues did not regulate MalP endocytosis and its interaction with HulA. Although α-amylase production was significantly repressed by creD deletion, both phosphorylation and dephosphorylation mimics of CreD had a negligible effect on α-amylase activity. Interestingly, dephosphorylation of CreD was required for CCR relief of amylase genes that was triggered by disruption of the deubiquitinating enzyme-encoding gene creB The α-amylase activity of the creB mutant was 1.6-fold higher than that of the wild type, and the dephosphorylation mimic of CreD further improved the α-amylase activity by 2.6-fold. These results indicate that a combination of the dephosphorylation mutation of CreD and creB disruption increased the production of amylolytic enzymes in A. oryzae IMPORTANCE In eukaryotes, glucose induces carbon catabolite repression (CCR) and proteolytic degradation of plasma membrane transporters via endocytosis. Glucose-induced endocytosis of transporters is mediated by

  1. DNA cytosine methylation in the bovine leukemia virus promoter is associated with latency in a lymphoma-derived B-cell line: potential involvement of direct inhibition of cAMP-responsive element (CRE)-binding protein/CRE modulator/activation transcription factor binding.

    Science.gov (United States)

    Pierard, Valérie; Guiguen, Allan; Colin, Laurence; Wijmeersch, Gaëlle; Vanhulle, Caroline; Van Driessche, Benoît; Dekoninck, Ann; Blazkova, Jana; Cardona, Christelle; Merimi, Makram; Vierendeel, Valérie; Calomme, Claire; Nguyên, Thi Liên-Anh; Nuttinck, Michèle; Twizere, Jean-Claude; Kettmann, Richard; Portetelle, Daniel; Burny, Arsène; Hirsch, Ivan; Rohr, Olivier; Van Lint, Carine

    2010-06-18

    Bovine leukemia virus (BLV) proviral latency represents a viral strategy to escape the host immune system and allow tumor development. Besides the previously demonstrated role of histone deacetylation in the epigenetic repression of BLV expression, we showed here that BLV promoter activity was induced by several DNA methylation inhibitors (such as 5-aza-2'-deoxycytidine) and that overexpressed DNMT1 and DNMT3A, but not DNMT3B, down-regulated BLV promoter activity. Importantly, cytosine hypermethylation in the 5'-long terminal repeat (LTR) U3 and R regions was associated with true latency in the lymphoma-derived B-cell line L267 but not with defective latency in YR2 cells. Moreover, the virus-encoded transactivator Tax(BLV) decreased DNA methyltransferase expression levels, which could explain the lower level of cytosine methylation observed in the L267(LTaxSN) 5'-LTR compared with the L267 5'-LTR. Interestingly, DNA methylation inhibitors and Tax(BLV) synergistically activated BLV promoter transcriptional activity in a cAMP-responsive element (CRE)-dependent manner. Mechanistically, methylation at the -154 or -129 CpG position (relative to the transcription start site) impaired in vitro binding of CRE-binding protein (CREB) transcription factors to their respective CRE sites. Methylation at -129 CpG alone was sufficient to decrease BLV promoter-driven reporter gene expression by 2-fold. We demonstrated in vivo the recruitment of CREB/CRE modulator (CREM) and to a lesser extent activating transcription factor-1 (ATF-1) to the hypomethylated CRE region of the YR2 5'-LTR, whereas we detected no CREB/CREM/ATF recruitment to the hypermethylated corresponding region in the L267 cells. Altogether, these findings suggest that site-specific DNA methylation of the BLV promoter represses viral transcription by directly inhibiting transcription factor binding, thereby contributing to true proviral latency.

  2. Consultation organised by CRE and CREG on the France-Belgium interconnection; Consultation organisee par la CRE et la CREG relative a la gestion de l'interconnexion France-Belgique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    In June 2002, RTE and ELIA put forward a proposal to CRE and CREG for setting up a new joint mechanism for allocating capacity on the Franco-Belgian border. As it contained a number of improvements, the regulators authorised its use as from July 1, 2002. At the same time, they announced that users would be consulted during Autumn 2002 on the way RTE's and ELIA's commitments had been reflected in contractual terms, the transparency of the allocation process, the new mechanism's overall efficiency and the possibility of allocating capacity on an annual basis. CRE and CREG ask everybody concerned by electricity transfers between France and Belgium to give his or her opinion on the way in which the interconnections new operating conditions contribute at present, or could contribute in the future, to developing fair and efficient competition on European Union electricity markets. (author)

  3. Rapid and sensitive detection of canine parvovirus type 2 by recombinase polymerase amplification.

    Science.gov (United States)

    Wang, Jianchang; Liu, Libing; Li, Ruiwen; Wang, Jinfeng; Fu, Qi; Yuan, Wanzhe

    2016-04-01

    A novel recombinase polymerase amplification (RPA)-based method for detection of canine parvovirus type 2 (CPV-2) was developed. Sensitivity analysis showed that the detection limit of RPA was 10 copies of CPV-2 genomic DNA. RPA amplified both CPV-2a and -2b DNA but did not amplify the template of other important dog viruses (CCoV, PRV or CDV), demonstrating high specificity. The method was further validated with 57 canine fecal samples. An outstanding advantage of RPA is that it is an isothermal reaction and can be performed in a water bath, making RPA a potential alternative method for CPV-2 detection in resource-limited settings.

  4. Development of a rapid diagnostic assay for the detection of tomato chlorotic dwarf viroid based on isothermal reverse-transcription-recombinase polymerase amplification

    Science.gov (United States)

    A molecular diagnostic assay utilizing reverse transcription-recombinase polymerase amplification (RT-RPA) at an isothermal constant temperature of 39 °C and target-specific primers and probe were developed for the rapid, sensitive, and specific detection of tomato chlorotic dwarf viroid (TCDVd) in ...

  5. Role of allosteric switch residue histidine 195 in maintaining active-site asymmetry in presynaptic filaments of bacteriophage T4 UvsX recombinase.

    Science.gov (United States)

    Farb, Joshua N; Morrical, Scott W

    2009-01-16

    Recombinases of the highly conserved RecA/Rad51 family play central roles in homologous recombination and DNA double-stranded break repair. RecA/Rad51 enzymes form presynaptic filaments on single-stranded DNA (ssDNA) that are allosterically activated to catalyze ATPase and DNA strand-exchange reactions. Information is conveyed between DNA- and ATP-binding sites, in part, by a highly conserved glutamine residue (Gln194 in Escherichia coli RecA) that acts as an allosteric switch. The T4 UvsX protein is a divergent RecA ortholog and contains histidine (His195) in place of glutamine at the allosteric switch position. UvsX and RecA catalyze similar strand-exchange reactions, but differ in other properties. UvsX produces both ADP and AMP as products of its ssDNA-dependent ATPase activity--a property that is unique among characterized recombinases. Details of the kinetics of ssDNA-dependent ATP hydrolysis reactions indicate that UvsX-ssDNA presynaptic filaments are asymmetric and contain two classes of ATPase active sites: one that generates ADP, and another that generates AMP. Active-site asymmetry is reduced by mutations at the His195 position, since UvsX-H195Q and UvsX-H195A mutants both exhibit stronger ssDNA-dependent ATPase activity, with lower cooperativity and markedly higher ADP/AMP product ratios, than wild-type UvsX. Reduced active-site asymmetry correlates strongly with reduced ssDNA-binding affinity and DNA strand-exchange activity in both H195Q and H195A mutants. These and other results support a model in which allosteric switch residue His195 controls the formation of an asymmetric conformation of UvsX-ssDNA filaments that is active in DNA strand exchange. The implications of our findings for UvsX recombination functions, and for RecA functions in general, are discussed.

  6. Layer- and column-specific knockout of NMDA receptors in pyramidal neurons of the mouse barrel cortex.

    Directory of Open Access Journals (Sweden)

    Rachel Aronoff

    2007-11-01

    Full Text Available Viral vectors injected into the mouse brain offer the possibility for localized genetic modifications in a highly controlled manner. Lentivector injection into mouse neocortex transduces cells within a diameter of approximately 200µm, which closely matches the lateral scale of a column in barrel cortex. The depth and volume of the injection determines which cortical layer is transduced. Furthermore, transduced gene expression from the lentivector can be limited to predominantly pyramidal neurons by using a 1.3kb fragment of the αCaMKII promoter. This technique therefore allows genetic manipulation of a specific cell type in defined columns and layers of the neocortex. By expressing Cre recombinase from such a lentivector in gene-targeted mice carrying a floxed gene, highly specific genetic lesions can be induced. Here, we demonstrate the utility of this approach by specifically knocking out NMDA receptors (NMDARs in pyramidal neurons in the somatosensory barrel cortex of gene-targeted mice carrying floxed NMDAR 1 genes. Neurons transduced with lentivector encoding GFP and Cre recombinase exhibit not only reductions in NMDAR 1 mRNA levels, but reduced NMDAR-dependent currents and pairing-induced synaptic potentiation. This technique for knockout of NMDARs in a cell type, column- and layer-specific manner in the mouse somatosensory cortex may help further our understanding of the functional roles of NMDARs in vivo during sensory perception and learning.

  7. Recombinase Activating Gene 1 Deficiencies Without Omenn Syndrome May Also Present With Eosinophilia and Bone Marrow Fibrosis

    OpenAIRE

    Ulusoy, Ezgi; Karaca, Neslihan Edeer; Azarsiz, Elif; Berdeli, Afig; Aksu, Guzide; Kutukculer, Necil

    2016-01-01

    Background Severe combined immunodeficiency (SCID) syndromes are a heterogenous group of diseases characterized by impairment in both cellular and humoral immunity with a range of genetic disorders. Complete recombinase activating gene (RAG) deficiency is associated with classical T-B-NK+ SCID which is the most common phenotype of Turkish SCID patients. There is a broad spectrum of hypomorfic RAG mutations including Omenn syndrome, leaky or atypical SCID with expansion of ?? T cells, autoimmu...

  8. Cre/lox system to develop selectable marker free transgenic tobacco plants conferring resistance against sap sucking homopteran insect.

    Science.gov (United States)

    Chakraborti, Dipankar; Sarkar, Anindya; Mondal, Hossain A; Schuermann, David; Hohn, Barbara; Sarmah, Bidyut K; Das, Sampa

    2008-10-01

    A binary expression vector was constructed containing the insecticidal gene Allium sativum leaf agglutinin (ASAL), and a selectable nptII marker gene cassette, flanked by lox sites. Similarly, another binary vector was developed with the chimeric cre gene construct. Transformed tobacco plants were generated with these two independent vectors. Each of the T(0) lox plants was crossed with T(0) Cre plants. PCR analyses followed by the sequencing of the target T-DNA part of the hybrid T(1) plants demonstrated the excision of the nptII gene in highly precised manner in certain percentage of the T(1) hybrid lines. The frequency of such marker gene excision was calculated to be 19.2% in the hybrids. Marker free plants were able to express ASAL efficiently and reduce the survivability of Myzus persiceae, the deadly pest of tobacco significantly, compared to the control tobacco plants. Results of PCR and Southern blot analyses of some of the T(2) plants detected the absence of cre as well as nptII genes. Thus, the crossing strategy involving Cre/lox system for the excision of marker genes appears to be very effective and easy to execute. Documentation of such marker excision phenomenon in the transgenic plants expressing the important insecticidal protein for the first time has a great significance from agricultural and biotechnological points of view.

  9. Development of a general-purpose method for cell purification using Cre/loxP-mediated recombination.

    Science.gov (United States)

    Kuroki, Shunsuke; Akiyoshi, Mika; Ideguchi, Ko; Kitano, Satsuki; Miyachi, Hitoshi; Hirose, Michiko; Mise, Nathan; Abe, Kuniya; Ogura, Atsuo; Tachibana, Makoto

    2015-06-01

    A mammalian body is composed of more than 200 different types of cells. The purification of a certain cell type from tissues/organs enables a wide variety of studies. One popular cell purification method is immunological isolation, using antibodies against specific cell surface antigens. However, this is not a general-purpose method, since suitable antigens have not been found in certain cell types, including embryonic gonadal somatic cells and Sertoli cells. To address this issue, we established a knock-in mouse line, named R26 KI, designed to express the human cell surface antigen hCD271 through Cre/loxP-mediated recombination. First, we used the R26 Kl mouse line to purify embryonic gonadal somatic cells. Gonadal somatic cells were purified from the R26 KI; Nr5a1-Cre-transgenic (tg) embryos almost equally as efficiently as from Nr5a1-hCD271-tg embryos. Second, we used the R26 KI mouse line to purify Sertoli cells successfully from R26 KI; Amh-Cre-tg testes. In summary, we propose that the R26 KI mouse line is a powerful tool for the purification of various cell types. © 2015 Wiley Periodicals, Inc.

  10. v-src induction of the TIS10/PGS2 prostaglandin synthase gene is mediated by an ATF/CRE transcription response element.

    Science.gov (United States)

    Xie, W; Fletcher, B S; Andersen, R D; Herschman, H R

    1994-10-01

    We recently reported the cloning of a mitogen-inducible prostaglandin synthase gene, TIS10/PGS2. In addition to growth factors and tumor promoters, the v-src oncogene induces TIS10/PGS2 expression in 3T3 cells. Deletion analysis, using luciferase reporters, identifies a region between -80 and -40 nucleotides 5' of the TIS10/PGS2 transcription start site that mediates pp60v-src induction in 3T3 cells. This region contains the sequence CGTCACGTG, which includes overlapping ATF/CRE (CGTCA) and E-box (CACGTG) sequences. Gel shift-oligonucleotide competition experiments with nuclear extracts from cells stably transfected with a temperature-sensitive v-src gene demonstrate that the CGTCACGTG sequence can bind proteins at both the ATF/CRE and E-box sequences. Dominant-negative CREB and Myc proteins that bind DNA, but do not transactivate, block v-src induction of a luciferase reporter driven by the first 80 nucleotides of the TIS10/PGS2 promoter. Mutational analysis distinguishes which TIS10/PGS2 cis-acting element mediates pp60v-src induction. E-box mutation has no effect on the fold induction in response to pp60v-src. In contrast, ATF/CRE mutation attenuates the pp60v-src response. Antibody supershift and methylation interference experiments demonstrate that CREB and at least one other ATF transcription factor in these extracts bind to the TIS10/PGS2 ATF/CRE element. Expression of a dominant-negative ras gene also blocks TIS10/PGS2 induction by v-src. Our data suggest that Ras mediates pp60v-src activation of an ATF transcription factor, leading to induced TIS10/PGS2 expression via the ATF/CRE element of the TIS10/PGS2 promoter. This is the first description of v-src activation of gene expression via an ATF/CRE element.

  11. Evidence from cosmic ray exposure (CRE) dating for the existence of a pre-Minoan caldera on Santorini, Greece

    Science.gov (United States)

    Athanassas, C. D.; Bourlès, D. L.; Braucher, R.; Druitt, T. H.; Nomikou, P.; Léanni, L.

    2016-05-01

    Cosmic ray exposure (CRE) dating was performed on the caldera cliffs of Santorini with the aim of detecting cliff segments predating the Minoan eruption (17th century BCE). The methodology involved the determination of in situ-produced cosmogenic 36Cl concentration in basaltic-to-rhyodacitic whole rocks cropping out in the cliffs. After the samples were processed following the chemical protocol of 36Cl preparation for silicate rocks, 36Cl concentrations were measured by accelerator mass spectrometry (AMS). Important challenges during the implementation procedure were related to large amounts of radiogenic 36Cl, complex modeling of inherited 36Cl, and dominance of the thermal and epithermal (low-energy) neutron capture production pathway. Nevertheless, quantitative assessments on the basis of the contribution of the low-energy neutron capture pathway percent to the total production rate validated the calculated CRE dates. Current CRE ages demonstrate that an ancient caldera existed on pre-Minoan Santorini, occupying at least the northern half of the modern-day caldera.

  12. Lactoferricin B Inhibits the Phosphorylation of the Two-Component System Response Regulators BasR and CreB*

    Science.gov (United States)

    Ho, Yu-Hsuan; Sung, Tzu-Cheng; Chen, Chien-Sheng

    2012-01-01

    Natural antimicrobial peptides provide fundamental protection for multicellular organisms from microbes, such as Lactoferricin B (Lfcin B). Many studies have shown that Lfcin B penetrates the cell membrane and has intracellular activities. To elucidate the intracellular behavior of Lfcin B, we first used Escherichia coli K12 proteome chips to identify the intracellular targets of Lfcin B. The results showed that Lfcin B binds to two response regulators, BasR and CreB, of the two-component system. For further analysis, we conducted several in vitro and in vivo experiments and utilized bioinformatics methods. The electrophoretic mobility shift assays and kinase assays indicate that Lfcin B inhibits the phosphorylation of the response regulators (BasR and CreB) and their cognate sensor kinases (BasS and CreC). Antibacterial assays showed that Lfcin B reduced E. coli's tolerance to environmental stimuli, such as excessive ferric ions and minimal medium conditions. This is the first study to show that an antimicrobial peptide inhibits the growth of bacteria by influencing the phosphorylation of a two-component system directly. PMID:22138548

  13. Lactoferricin B inhibits the phosphorylation of the two-component system response regulators BasR and CreB.

    Science.gov (United States)

    Ho, Yu-Hsuan; Sung, Tzu-Cheng; Chen, Chien-Sheng

    2012-04-01

    Natural antimicrobial peptides provide fundamental protection for multicellular organisms from microbes, such as Lactoferricin B (Lfcin B). Many studies have shown that Lfcin B penetrates the cell membrane and has intracellular activities. To elucidate the intracellular behavior of Lfcin B, we first used Escherichia coli K12 proteome chips to identify the intracellular targets of Lfcin B. The results showed that Lfcin B binds to two response regulators, BasR and CreB, of the two-component system. For further analysis, we conducted several in vitro and in vivo experiments and utilized bioinformatics methods. The electrophoretic mobility shift assays and kinase assays indicate that Lfcin B inhibits the phosphorylation of the response regulators (BasR and CreB) and their cognate sensor kinases (BasS and CreC). Antibacterial assays showed that Lfcin B reduced E. coli's tolerance to environmental stimuli, such as excessive ferric ions and minimal medium conditions. This is the first study to show that an antimicrobial peptide inhibits the growth of bacteria by influencing the phosphorylation of a two-component system directly.

  14. Role of ptsP, orfT, and sss recombinase genes in root colonization by Pseudomonas fluorescens Q8r1-96.

    Science.gov (United States)

    Mavrodi, Olga V; Mavrodi, Dmitri V; Weller, David M; Thomashow, Linda S

    2006-11-01

    Pseudomonas fluorescens Q8r1-96 produces 2,4-diacetylphloroglucinol (2,4-DAPG), a polyketide antibiotic that suppresses a wide variety of soilborne fungal pathogens, including Gaeumannomyces graminis var. tritici, which causes take-all disease of wheat. Strain Q8r1-96 is representative of the D-genotype of 2,4-DAPG producers, which are exceptional because of their ability to aggressively colonize and maintain large populations on the roots of host plants, including wheat, pea, and sugar beet. In this study, three genes, an sss recombinase gene, ptsP, and orfT, which are important in the interaction of Pseudomonas spp. with various hosts, were investigated to determine their contributions to the unusual colonization properties of strain Q8r1-96. The sss recombinase and ptsP genes influence global processes, including phenotypic plasticity and organic nitrogen utilization, respectively. The orfT gene contributes to the pathogenicity of Pseudomonas aeruginosa in plants and animals and is conserved among saprophytic rhizosphere pseudomonads, but its function is unknown. Clones containing these genes were identified in a Q8r1-96 genomic library, sequenced, and used to construct gene replacement mutants of Q8r1-96. Mutants were characterized to determine their 2,4-DAPG production, motility, fluorescence, colony morphology, exoprotease and hydrogen cyanide (HCN) production, carbon and nitrogen utilization, and ability to colonize the rhizosphere of wheat grown in natural soil. The ptsP mutant was impaired in wheat root colonization, whereas mutants with mutations in the sss recombinase gene and orfT were not. However, all three mutants were less competitive than wild-type P. fluorescens Q8r1-96 in the wheat rhizosphere when they were introduced into the soil by paired inoculation with the parental strain.

  15. Recombinase polymerase and enzyme-linked immunosorbent assay as a DNA amplification-detection strategy for food analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santiago-Felipe, S.; Tortajada-Genaro, L.A.; Puchades, R.; Maquieira, A., E-mail: amaquieira@qim.upv.es

    2014-02-06

    Graphical abstract: -- Highlights: •Recombinase polymerase amplification is a powerful DNA method operating at 40 °C. •The combination RPA–ELISA gives excellent performances for high-throughput analysis. •Screening of food safety threats has been done using standard laboratory equipment. •Allergens, GMOs, bacteria, and fungi have been successfully determined. -- Abstract: Polymerase chain reaction in conjunction with enzyme-linked immunosorbent assay (PCR–ELISA) is a well-established technique that provides a suitable rapid, sensitive, and selective method for a broad range of applications. However, the need for precise rapid temperature cycling of PCR is an important drawback that can be overcome by employing isothermal amplification reactions such as recombinase polymerase amplification (RPA). The RPA–ELISA combination is proposed for amplification at a low, constant temperature (40 °C) in a short time (40 min), for the hybridisation of labelled products to specific 5′-biotinylated probes/streptavidin in coated microtiter plates at room temperature, and for detection by colorimetric immunoassay. RPA–ELISA was applied to screen common safety threats in foodstuffs, such as allergens (hazelnut, peanut, soybean, tomato, and maize), genetically modified organisms (P35S and TNOS), pathogenic bacteria (Salmonella sp. and Cronobacter sp.), and fungi (Fusarium sp.). Satisfactory sensitivity and reproducibility results were achieved for all the targets. The RPA–ELISA technique does away with thermocycling and provides a suitable sensitive, specific, and cost-effective method for routine applications, and proves particularly useful for resource-limited settings.

  16. Recombinase polymerase and enzyme-linked immunosorbent assay as a DNA amplification-detection strategy for food analysis

    International Nuclear Information System (INIS)

    Santiago-Felipe, S.; Tortajada-Genaro, L.A.; Puchades, R.; Maquieira, A.

    2014-01-01

    Graphical abstract: -- Highlights: •Recombinase polymerase amplification is a powerful DNA method operating at 40 °C. •The combination RPA–ELISA gives excellent performances for high-throughput analysis. •Screening of food safety threats has been done using standard laboratory equipment. •Allergens, GMOs, bacteria, and fungi have been successfully determined. -- Abstract: Polymerase chain reaction in conjunction with enzyme-linked immunosorbent assay (PCR–ELISA) is a well-established technique that provides a suitable rapid, sensitive, and selective method for a broad range of applications. However, the need for precise rapid temperature cycling of PCR is an important drawback that can be overcome by employing isothermal amplification reactions such as recombinase polymerase amplification (RPA). The RPA–ELISA combination is proposed for amplification at a low, constant temperature (40 °C) in a short time (40 min), for the hybridisation of labelled products to specific 5′-biotinylated probes/streptavidin in coated microtiter plates at room temperature, and for detection by colorimetric immunoassay. RPA–ELISA was applied to screen common safety threats in foodstuffs, such as allergens (hazelnut, peanut, soybean, tomato, and maize), genetically modified organisms (P35S and TNOS), pathogenic bacteria (Salmonella sp. and Cronobacter sp.), and fungi (Fusarium sp.). Satisfactory sensitivity and reproducibility results were achieved for all the targets. The RPA–ELISA technique does away with thermocycling and provides a suitable sensitive, specific, and cost-effective method for routine applications, and proves particularly useful for resource-limited settings

  17. Notchless is required for axial skeleton formation in mice.

    Directory of Open Access Journals (Sweden)

    Sarah Beck-Cormier

    Full Text Available Maintenance of cell survival is essential for proper embryonic development. In the mouse, Notchless homolog 1 (Drosophila (Nle1 is instrumental for survival of cells of the inner cell mass upon implantation. Here, we analyze the function of Nle1 after implantation using the Meox2(tm1(creSor mouse that expresses the Cre recombinase specifically in the epiblast at E5.5. First, we find that NLE1 function is required in epiblast cells, as Nle1-deficient cells are rapidly eliminated. In this report, we also show that the Meox2(Cre transgene is active in specific tissues during organogenesis. In particular, we detect high Cre expression in the vertebral column, ribs, limbs and tailbud. We took advantage of this dynamic expression profile to analyze the effects of inducing mosaic deletion of Nle1 in the embryo. We show that Nle1 deletion in this context, results in severe developmental anomalies leading to lethality at birth. Mutant embryos display multiple developmental defects in particular during axial skeletal formation. We also provide evidence that axial defects are due to an increase in apoptotic cell death in the somite at E9.5. These data demonstrate an essential role for Nle1 during organogenesis and in particular during axial development.

  18. Notchless is required for axial skeleton formation in mice.

    Science.gov (United States)

    Beck-Cormier, Sarah; Escande, Marie; Souilhol, Céline; Vandormael-Pournin, Sandrine; Sourice, Sophie; Pilet, Paul; Babinet, Charles; Cohen-Tannoudji, Michel

    2014-01-01

    Maintenance of cell survival is essential for proper embryonic development. In the mouse, Notchless homolog 1 (Drosophila) (Nle1) is instrumental for survival of cells of the inner cell mass upon implantation. Here, we analyze the function of Nle1 after implantation using the Meox2(tm1(cre)Sor) mouse that expresses the Cre recombinase specifically in the epiblast at E5.5. First, we find that NLE1 function is required in epiblast cells, as Nle1-deficient cells are rapidly eliminated. In this report, we also show that the Meox2(Cre) transgene is active in specific tissues during organogenesis. In particular, we detect high Cre expression in the vertebral column, ribs, limbs and tailbud. We took advantage of this dynamic expression profile to analyze the effects of inducing mosaic deletion of Nle1 in the embryo. We show that Nle1 deletion in this context, results in severe developmental anomalies leading to lethality at birth. Mutant embryos display multiple developmental defects in particular during axial skeletal formation. We also provide evidence that axial defects are due to an increase in apoptotic cell death in the somite at E9.5. These data demonstrate an essential role for Nle1 during organogenesis and in particular during axial development.

  19. Localization of recombination proteins and Srs2 reveals anti-recombinase function in vivo

    DEFF Research Database (Denmark)

    Burgess, Rebecca C; Lisby, Michael; Altmannova, Veronika

    2009-01-01

    , and surprisingly, can form in the absence of Rad52 mediation. However, these Rad51 foci do not represent repair-proficient filaments, as determined by recombination assays. Antagonistic roles for Rad52 and Srs2 in Rad51 filament formation are also observed in vitro. Furthermore, we provide evidence that Srs2......Homologous recombination (HR), although an important DNA repair mechanism, is dangerous to the cell if improperly regulated. The Srs2 "anti-recombinase" restricts HR by disassembling the Rad51 nucleoprotein filament, an intermediate preceding the exchange of homologous DNA strands. Here, we...... removes Rad51 indiscriminately from DNA, while the Rad52 protein coordinates appropriate filament reformation. This constant breakdown and rebuilding of filaments may act as a stringent quality control mechanism during HR....

  20. Matrix metalloproteinase-9 (MMP9) is involved in the TNF-α-induced fusion of human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells.

    Science.gov (United States)

    Weiler, Julian; Mohr, Marieke; Zänker, Kurt S; Dittmar, Thomas

    2018-04-10

    In addition to physiological events such as fertilisation, placentation, osteoclastogenesis, or tissue regeneration/wound healing, cell fusion is involved in pathophysiological conditions such as cancer. Cell fusion, which applies to both the proteins and conditions that induce the merging of two or more cells, is not a fully understood process. Inflammation/pro-inflammatory cytokines might be a positive trigger for cell fusion. Using a Cre-LoxP-based cell fusion assay we demonstrated that the fusion between human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells was induced by the pro-inflammatory cytokine tumour necrosis factor-α (TNF-α). The gene expression profile of the cells in the presence of TNF-α and under normoxic and hypoxic conditions was analysed by cDNA microarray analysis. cDNA microarray data were verified by qPCR, PCR, Western blot and zymography. Quantification of cell fusion events was determined by flow cytometry. Proteins of interest were either blocked or knocked-down using a specific inhibitor, siRNA or a blocking antibody. The data showed an up-regulation of various genes, including claudin-1 (CLDN1), ICAM1, CCL2 and MMP9 in M13SV1-Cre and/or MDA-MB-435-pFDR1 cells. Inhibition of these proteins using a blocking ICAM1 antibody, CLDN1 siRNA or an MMP9 inhibitor showed that only the blockage of MMP9 was correlated with a decreased fusion rate of the cells. Likewise, the tetracycline-based antibiotic minocycline, which exhibits anti-inflammatory properties, was also effective in both inhibiting the TNF-α-induced MMP9 expression in M13SV1-Cre cells and blocking the TNF-α-induced fusion frequency of human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells. The matrix metalloproteinase-9 (MMP9) is most likely involved in the TNF-α-mediated fusion of human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells. Likewise, our data indicate that the tetracycline

  1. Down, But Not Out: Partial Elimination of Androgen Receptors in the Male Mouse Brain Does Not Affect Androgenic Regulation of Anxiety or HPA Activity.

    Science.gov (United States)

    Chen, Chieh V; Brummet, Jennifer L; Jordan, Cynthia L; Breedlove, S Marc

    2016-02-01

    We previously found that androgen receptor (AR) activity mediates two effects of T in adult male mice: reduction of anxiety-like behaviors and dampening of the hypothalamic-pituitary-adrenal response to stress. To determine whether brain ARs mediate these effects, we used the Cre/loxP technology seeking to disable AR throughout the central nervous system (CNS). Female mice carrying the floxed AR allele (ARlox) were crossed with males carrying cre recombinase transgene controlled by the nestin promoter (NesCre), producing cre in developing neurons and glia. Among male offspring, four genotypes resulted: males carrying ARlox and NesCre (NesARko), and three control groups (wild types, NesCre, and ARlox). Reporter mice indicated ubiquitous Cre expression throughout the CNS. Nevertheless, AR immunocytochemistry in NesARko mice revealed efficient knockout (KO) of AR in some brain regions (hippocampus and medial prefrontal cortex [mPFC]), but not others. Substantial AR protein was seen in the amygdala and hypothalamus among other regions, whereas negligible AR remained in others like the bed nucleus of the stria terminalis and dorsal periaqueductal gray. This selective KO allowed for testing the role of AR in hippocampus and mPFC. Males were castrated and implanted with T at postnatal day 60 before testing on postnatal day 90-100. In contrast with males with global KO of AR, T still modulated anxiety-related behavior and hypothalamic-pituitary-adrenal activity in NesARko males. These results leave open the possibility that AR acting in the CNS mediates these effects of T, but demonstrate that AR is not required in the hippocampus or mPFC for T's anxiolytic effects.

  2. v-src Induction of the TIS10/PGS2 prostaglandin synthase gene is mediated by an ATF/CRE transcription response element

    Energy Technology Data Exchange (ETDEWEB)

    Xie, W.; Fletcher, B.S.; Andersen, R.D.; Herschman, H.R. [Univ. of California, Los Angeles, CA (United States)

    1994-10-01

    The authors recently reported the cloning of a mitogen-inducible prostaglandin synthase gene, TIS10/PGS2. In addition to growth factor and tumor promoters, the v-src oncogene induces TIS10/PGS2 expression in 3T3 cells. Deletion analysis, using luciferase reporters, identifies a region between -80 and -40 nucleotides 5{prime} of the TIS10/PGS2 transcription start site that mediates pp60{sup v-src} induction in 3T3 cells. This region contains the sequence CGTCACGTG, which includes overlapping ATF/CRE (CGTCA) and E-box (CACGTG) sequences. Gel shift-oligonucleotide competition experiments with nuclear extracts from cells stably transfected with a temperature-sensitive v-src gene demonstrate that the CGTCACGTG sequence can bind proteins at both the AFT/CRE and E-box sequences. Dominant-negative CREB and Myc proteins that bind DNA, but do not transactivate, block v-src induction of a luciferase reporter driven by the first 80 nucleotides of the TIS10/PGS2 promoter. Mutational analysis distinguishes which TIS10/PGS2 cis-acting element mediates pp60{sup v-src} induction. E-box mutation has no effect on the fold induction in response to pp60{sup v-src}. In contrast, ATF/CRE mutation attenuates the pp{sup v-src} response. Antibody supershift and methylation interference experiments demonstrate that CREB and at least one other ATF transcription factor in these extracts bind to the TIS10/PGS2 ATF/CRE element. Expression of a dominant-negative ras gene also blocks TIS10/PGS2 induction by v-src. The data suggest that Ras mediates pp60{sup v-src} activation of an ATF transcription factor, leading to induced TIS10/PGS2 expression via the ATF/CRE element of the TIS10/PGS2 promoter. This is the first description of v-src activation of gene expression via an ATF/CRE element. 64 refs., 8 figs.

  3. Pivotal Role of O-GlcNAc Modification in Cold-Induced Thermogenesis by Brown Adipose Tissue Through Mitochondrial Biogenesis.

    Science.gov (United States)

    Ohashi, Natsuko; Morino, Katsutaro; Ida, Shogo; Sekine, Osamu; Lemecha, Mengistu; Kume, Shinji; Park, Shi-Young; Choi, Cheol Soo; Ugi, Satoshi; Maegawa, Hiroshi

    2017-09-01

    Adipose tissues considerably influence metabolic homeostasis, and both white (WAT) and brown (BAT) adipose tissue play significant roles in lipid and glucose metabolism. O -linked N -acetylglucosamine ( O -GlcNAc) modification is characterized by the addition of N -acetylglucosamine to various proteins by O -GlcNAc transferase (Ogt), subsequently modulating various cellular processes. However, little is known about the role of O -GlcNAc modification in adipose tissues. Here, we report the critical role of O -GlcNAc modification in cold-induced thermogenesis. Deletion of Ogt in WAT and BAT using adiponectin promoter-driven Cre recombinase resulted in severe cold intolerance with decreased uncoupling protein 1 (Ucp1) expression. Furthermore, Ogt deletion led to decreased mitochondrial protein expression in conjunction with decreased peroxisome proliferator-activated receptor γ coactivator 1-α protein expression. This phenotype was further confirmed by deletion of Ogt in BAT using Ucp1 promoter-driven Cre recombinase, suggesting that O -GlcNAc modification in BAT is responsible for cold-induced thermogenesis. Hypothermia was significant under fasting conditions. This effect was mitigated after normal diet consumption but not after consumption of a fatty acid-rich ketogenic diet lacking carbohydrates, suggesting impaired diet-induced thermogenesis, particularly by fat. In conclusion, O -GlcNAc modification is essential for cold-induced thermogenesis and mitochondrial biogenesis in BAT. Glucose flux into BAT may be a signal to maintain BAT physiological responses. © 2017 by the American Diabetes Association.

  4. A CRE/AP-1-like motif is essential for induced syncytin-2 expression and fusion in human trophoblast-like model.

    Directory of Open Access Journals (Sweden)

    Chirine Toufaily

    Full Text Available Syncytin-2 is encoded by the envelope gene of Endogenous Retrovirus-FRD (ERVFRD-1 and plays a critical role in fusion of placental trophoblasts leading to the formation of the multinucleated syncytiotrophoblast. Its expression is consequently regulated in a strict manner. In the present study, we have identified a forskolin-responsive region located between positions -300 to -150 in the Syncytin-2 promoter region. This 150 bp region in the context of a minimal promoter mediated an 80-fold induction of promoter activity following forskolin stimulation. EMSA analyses with competition experiments with nuclear extracts from forskolin-stimulated BeWo cells demonstrated that the -211 to -177 region specifically bound two forskolin-induced complexes, one of them containing a CRE/AP-1-like motif. Site-directed mutagenesis of the CRE/AP-1 binding site in the context of the Syncytin-2 promoter or a heterologous promoter showed that this motif was mostly essential for forskolin-induced promoter activity. Transfection experiments with dominant negative mutants and constitutively activated CREB expression vectors in addition to Chromatin Immunoprecipitation suggested that a CREB family member, CREB2 was binding and acting through the CRE/AP-1 motif. We further demonstrated the binding of JunD to this same motif. Similar to forskolin and soluble cAMP, CREB2 and JunD overexpression induced Syncytin-2 promoter activity in a CRE/AP-1-dependent manner and Syncytin-2 expression. In addition, BeWo cell fusion was induced by both CREB2 and JunD overexpression, while being repressed following silencing of either gene. These results thereby demonstrate that induced expression of Syncytin-2 is highly dependent on the interaction of bZIP-containing transcription factors to a CRE/AP-1 motif and that this element is important for the regulation of Syncytin-2 expression, which results in the formation of the peripheral syncytiotrophoblast layer.

  5. Grin1 receptor deletion within CRF neurons enhances fear memory.

    Directory of Open Access Journals (Sweden)

    Georgette Gafford

    Full Text Available Corticotropin releasing factor (CRF dysregulation is implicated in mood and anxiety disorders such as posttraumatic stress disorder (PTSD. CRF is expressed in areas engaged in fear and anxiety processing including the central amygdala (CeA. Complicating our ability to study the contribution of CRF-containing neurons to fear and anxiety behavior is the wide variety of cell types in which CRF is expressed. To manipulate specific subpopulations of CRF containing neurons, our lab has developed a mouse with a Cre recombinase gene driven by a CRF promoter (CRFp3.0Cre (Martin et al., 2010. In these studies, mice that have the gene that encodes NR1 (Grin1 flanked by loxP sites (floxed were crossed with our previously developed CRFp3.0Cre mouse to selectively disrupt Grin1 within CRF containing neurons (Cre+/fGrin1+. We find that disruption of Grin1 in CRF neurons did not affect baseline levels of anxiety, locomotion, pain sensitivity or exploration of a novel object. However, baseline expression of Grin1 was decreased in Cre+/fGrin1+ mice as measured by RTPCR. Cre+/fGrin1+ mice showed enhanced auditory fear acquisition and retention without showing any significant effect on fear extinction. We measured Gria1, the gene that encodes AMPAR1 and the CREB activator Creb1 in the amygdala of Cre+/fGrin1+ mice after fear conditioning. Both Gria1 and Creb1 were enhanced in the amygdala after training. To determine if the Grin1-expressing CRF neurons within the CeA are responsible for the enhancement of fear memory in adults, we infused a lentivirus with Cre driven by a CRF promoter (LV pCRF-Cre/fGrin1+ into the CeA of floxed Grin1 mice. Cre driven deletion of Grin1 specifically within CRF expressing cells in the CeA also resulted in enhanced fear memory acquisition and retention. Altogether, these findings suggest that selective disruption of Grin1 within CeA CRF neurons strongly enhances fear memory.

  6. Cdk5 modulates cocaine reward, motivation, and striatal neuron excitability.

    Science.gov (United States)

    Benavides, David R; Quinn, Jennifer J; Zhong, Ping; Hawasli, Ammar H; DiLeone, Ralph J; Kansy, Janice W; Olausson, Peter; Yan, Zhen; Taylor, Jane R; Bibb, James A

    2007-11-21

    Cyclin-dependent kinase 5 (Cdk5) regulates dopamine neurotransmission and has been suggested to serve as a homeostatic target of chronic psychostimulant exposure. To study the role of Cdk5 in the modulation of the cellular and behavioral effects of psychoactive drugs of abuse, we developed Cre/loxP conditional knock-out systems that allow temporal and spatial control of Cdk5 expression in the adult brain. Here, we report the generation of Cdk5 conditional knock-out (cKO) mice using the alphaCaMKII promoter-driven Cre transgenic line (CaMKII-Cre). In this model system, loss of Cdk5 in the adult forebrain increased the psychomotor-activating effects of cocaine. Additionally, these CaMKII-Cre Cdk5 cKO mice show enhanced incentive motivation for food as assessed by instrumental responding on a progressive ratio schedule of reinforcement. Behavioral changes were accompanied by increased excitability of medium spiny neurons in the nucleus accumbens (NAc) in Cdk5 cKO mice. To study NAc-specific effects of Cdk5, another model system was used in which recombinant adeno-associated viruses expressing Cre recombinase caused restricted loss of Cdk5 in NAc neurons. Targeted knock-out of Cdk5 in the NAc facilitated cocaine-induced locomotor sensitization and conditioned place preference for cocaine. These results suggest that Cdk5 acts as a negative regulator of neuronal excitability in the NAc and that Cdk5 may govern the behavioral effects of cocaine and motivation for reinforcement.

  7. Subset of Cortical Layer 6b Neurons Selectively Innervates Higher Order Thalamic Nuclei in Mice.

    Science.gov (United States)

    Hoerder-Suabedissen, Anna; Hayashi, Shuichi; Upton, Louise; Nolan, Zachary; Casas-Torremocha, Diana; Grant, Eleanor; Viswanathan, Sarada; Kanold, Patrick O; Clasca, Francisco; Kim, Yongsoo; Molnár, Zoltán

    2018-05-01

    The thalamus receives input from 3 distinct cortical layers, but input from only 2 of these has been well characterized. We therefore investigated whether the third input, derived from layer 6b, is more similar to the projections from layer 6a or layer 5. We studied the projections of a restricted population of deep layer 6 cells ("layer 6b cells") taking advantage of the transgenic mouse Tg(Drd1a-cre)FK164Gsat/Mmucd (Drd1a-Cre), that selectively expresses Cre-recombinase in a subpopulation of layer 6b neurons across the entire cortical mantle. At P8, 18% of layer 6b neurons are labeled with Drd1a-Cre::tdTomato in somatosensory cortex (SS), and some co-express known layer 6b markers. Using Cre-dependent viral tracing, we identified topographical projections to higher order thalamic nuclei. VGluT1+ synapses formed by labeled layer 6b projections were found in posterior thalamic nucleus (Po) but not in the (pre)thalamic reticular nucleus (TRN). The lack of TRN collaterals was confirmed with single-cell tracing from SS. Transmission electron microscopy comparison of terminal varicosities from layer 5 and layer 6b axons in Po showed that L6b varicosities are markedly smaller and simpler than the majority from L5. Our results suggest that L6b projections to the thalamus are distinct from both L5 and L6a projections.

  8. CRE deliberation concerning balancing regime developments for the natural gas transmission network in France

    International Nuclear Information System (INIS)

    2006-06-01

    GRTgaz has presented a project of progressive changeover to a new market-based balancing system, according to the following principles: quantities of gas required to ensure transmission network balancing are purchased from or sold on the daily and intra-day market by transmission system operators (TSOs); a daily gas balancing price reflecting actual costs borne by every TSO is defined according to these purchases and sales; every day, each shipper residual position after use of the available flexibility and tolerance, is cleared off by transactions at the daily balancing gas price, under terms encouraging shippers to minimise their imbalance. In order to incorporate current development of the French market, which still has low liquidity, GRTgaz proposes to progressively develop the volume of its market transactions. Within this context, from 4 May to 6 June 2006, CRE organised a public consultation concerning balancing regime developments, a summary of which is presented. The last part concerns the CRE decisions. (A.L.B.)

  9. The aging behavior of types 308 and 308CRE stainless steels and its effect on mechanical properties

    International Nuclear Information System (INIS)

    Vitek, J.M.; David, S.A.

    1987-01-01

    Aging of 308 and 308CRE SS was studied at 475 to 850 0 C for aging times up to 10,000 hours. Above 550 0 C, aging of 308 steel resulted in precipitation of carbides and the transformation of ferrite to sigma phase or the formation of sigma phase in initially ferrite-free material. The elevated-temperature aging of 308CRE steel resulted in the precipitation of titanium-rich carbides, nitrides, and sulfides, and the transformation of ferrite to sigma phase. The distribution of precipitates was affected by the initial condition of the materials. The elevated-temperature creep properties, and in particular the improved properties of 308CRE, were related to the precipitate distribution. Below 550 0 C, aging of welded type 308 steel, precipitation of G-phase within the ferrite was observed, as well as the decomposition of ferrite into alpha and alpha prime. With the help of a novel mechanical properties microprobe, which was capable of determining the hardness of the minor constituent ferrite phase, the hardness behavior as a function of aging could be related to the microstructures. These results are interpreted in terms of the potential susceptibility of these alloys to 475 0 C embrittlement

  10. Conditional IL-2 gene deletion: consequences for T cell proliferation

    Directory of Open Access Journals (Sweden)

    Kendall A Smith

    2012-05-01

    Full Text Available To explore the role of interleukin-2 (IL-2 in T cell proliferation, and to circumvent the IL-2 deficiency autoimmune syndrome of conventional il2 gene deletion, mice were created to allow conditional il2 gene deletion when treated with the estrogen analogue, tamoxifen (TAM as adults. Splenocytes from four different mouse strains, C57Bl/6 wild type (WT, conventional IL-2 (-/-, TAM-treated Cre recombinase negative (Cre-/IL2fl/fl, and Cre+/IL-2fl/fl (Cre+, were activated with anti-CD3 and anti-CD28, and monitored for CD4+ and CD8+ T cell lymphocyte blastogenesis, aerobic glycolysis, BrdU incorporation into newly synthesized DNA, and CFSE dye dilution to monitor cell division. IL-2 production was monitored by quantitative ELISA and multiple additional cytokines were monitored by protein-bead arrays. Splenocytes from conventional IL-2 (-/- and TAM-treated Cre+ mice resulted in undetectable IL-2 production, so that both strains were IL-2 deficient. As monitored by flow cytometry, activated CD4+ and CD8+ T cells from WT, Cre+ and Cre- mice all underwent blastogenesis, whereas far fewer cells from conventional IL-2 (-/- mice did so. By comparison, only cells from IL-2 sufficient WT and Cre- switched to aerobic glycolysis as evidenced by a drop in media pH. Blastogenesis was mirrored by BrdU incorporation and CFSE dye dilution by CD4+ and CD8+ T cells from WT, Cre+ and Cre- mice, which were all equivalent, while proliferation of cells from conventional IL-2 (-/- mice was compromised. Splenocytes from IL-2 deficient conventional IL-2 (-/- mice produced low or undetectable other γc-chain cytokines (IL-4, IL-7, IL-9, IL-13, IL-15, and IL-21, whereas production of these γc-chain cytokines from IL-2-deficient conditional IL-2 (-/- Cre+ mice were comparable with WT and Cre- mice. These results indicate that CD4+ and CD8+ T cell blastogenesis cannot be attributable to IL-2 alone, but a switch to aerobic glycolysis is attributable to IL-2, and proliferation

  11. Defining POMC neurons using transgenic reagents: impact of transient Pomc expression in diverse immature neuronal populations.

    Science.gov (United States)

    Padilla, Stephanie L; Reef, Daniel; Zeltser, Lori M

    2012-03-01

    Melanocortin signaling plays a central role in the regulation of phenotypes related to body weight and energy homeostasis. To specifically target and study the function of proopiomelanocortin (POMC) neurons, Pomc promoter elements have been utilized to generate reporter and Cre recombinase transgenic reagents. Across gestation, we find that Pomc is dynamically expressed in many sites in the developing mouse forebrain, midbrain, hindbrain, spinal cord, and retina. Although Pomc expression in most embryonic brain regions is transient, it is sufficient to direct Cre-mediated recombination of floxed alleles. We visualize the populations affected by this transgene by crossing Pomc-Cre mice to ROSA reporter strains and identify 62 sites of recombination throughout the adult brain, including several nuclei implicated in energy homeostasis regulation. To compare the relationship between acute Pomc promoter activity and Pomc-Cre-mediated recombination at the single cell level, we crossed Pomc-enhanced green fluorescent protein (eGFP) and Pomc-Cre;ROSA-tdTomato lines. We detect the highest concentration of Pomc-eGFP+ cells in the arcuate nucleus of the hypothalamus and dentate gyrus but also observe smaller populations of labeled cells in the nucleus of the solitary tract, periventricular zone of the third ventricle, and cerebellum. Consistent with the dynamic nature of Pomc expression in the embryo, the vast majority of neurons marked with the tdTomato reporter do not express eGFP in the adult. Thus, recombination in off-target sites could contribute to physiological phenotypes using Pomc-Cre transgenics. For example, we find that approximately 83% of the cells in the arcuate nucleus of the hypothalamus immunoreactive for leptin-induced phosphorylated signal transducer and activator of transcription 3 are marked with Pomc-Cre;ROSA-tdTomato; only 13% of these are eGFP+ POMC neurons.

  12. A powerful transgenic tool for fate mapping and functional analysis of newly generated neurons

    Directory of Open Access Journals (Sweden)

    Vogt Weisenhorn Daniela M

    2010-12-01

    Full Text Available Abstract Background Lack of appropriate tools and techniques to study fate and functional integration of newly generated neurons has so far hindered understanding of neurogenesis' relevance under physiological and pathological conditions. Current analyses are either dependent on mitotic labeling, for example BrdU-incorporation or retroviral infection, or on the detection of transient immature neuronal markers. Here, we report a transgenic mouse model (DCX-CreERT2 for time-resolved fate analysis of newly generated neurons. This model is based on the expression of a tamoxifen-inducible Cre recombinase under the control of a doublecortin (DCX promoter, which is specific for immature neuronal cells in the CNS. Results In the DCX-CreERT2 transgenic mice, expression of CreERT2 was restricted to DCX+ cells. In the CNS of transgenic embryos and adult DCX-CreERT2 mice, tamoxifen administration caused the transient translocation of CreERT2 to the nucleus, allowing for the recombination of loxP-flanked sequences. In our system, tamoxifen administration at E14.5 resulted in reporter gene activation throughout the developing CNS of transgenic embryos. In the adult CNS, neurogenic regions were the primary sites of tamoxifen-induced reporter gene activation. In addition, reporter expression could also be detected outside of neurogenic regions in cells physiologically expressing DCX (e.g. piriform cortex, corpus callosum, hypothalamus. Four weeks after recombination, the vast majority of reporter-expressing cells were found to co-express NeuN, revealing the neuronal fate of DCX+ cells upon maturation. Conclusions This first validation demonstrates that our new DCX-CreERT2 transgenic mouse model constitutes a powerful tool to investigate neurogenesis, migration and their long-term fate of neuronal precursors. Moreover, it allows for a targeted activation or deletion of specific genes in neuronal precursors and will thereby contribute to unravel the molecular

  13. Rac1 Dosage Is Crucial for Normal Endochondral Bone Growth.

    Science.gov (United States)

    Suzuki, Dai; Bush, Jason R; Bryce, Dawn-Marie; Kamijo, Ryutaro; Beier, Frank

    2017-10-01

    Rac1, a member of the small Rho GTPase family, plays multiple cellular roles. Studies of mice conditionally lacking Rac1 have revealed essential roles for Rac1 in various tissues, including cartilage and limb mesenchyme, where Rac1 loss produces dwarfism and long bone shortening. To gain further insight into the role of Rac1 in skeletal development, we have used transgenic mouse lines to express a constitutively active (ca) Rac1 mutant protein in a Cre recombinase-dependent manner. Overexpression of caRac1 in limb bud mesenchyme or chondrocytes leads to reduced body weight and shorter bones compared with control mice. Histological analysis of growth plates showed that caRac1;Col2-Cre mice displayed ectopic hypertrophic chondrocytes in the proliferative zone and enlarged hypertrophic zones. These mice also displayed a reduced proportion of proliferating cell nuclear antigen-positive cells in the proliferative zone and nuclear β-catenin localization in the ectopic hypertrophic chondrocytes. Importantly, overexpression of caRac1 partially rescued the phenotypes of Rac1fl/fl;Col2-Cre and Rac1fl/fl;Prx1-Cre conditional knockout mice, including body weight, bone length, and growth plate disorganization. These results suggest that tight regulation of Rac1 activity is necessary for normal cartilage development. Copyright © 2017 Endocrine Society.

  14. A Convenient Cas9-based Conditional Knockout Strategy for Simultaneously Targeting Multiple Genes in Mouse.

    Science.gov (United States)

    Chen, Jiang; Du, Yinan; He, Xueyan; Huang, Xingxu; Shi, Yun S

    2017-03-31

    The most powerful way to probe protein function is to characterize the consequence of its deletion. Compared to conventional gene knockout (KO), conditional knockout (cKO) provides an advanced gene targeting strategy with which gene deletion can be performed in a spatially and temporally restricted manner. However, for most species that are amphiploid, the widely used Cre-flox conditional KO (cKO) system would need targeting loci in both alleles to be loxP flanked, which in practice, requires time and labor consuming breeding. This is considerably significant when one is dealing with multiple genes. CRISPR/Cas9 genome modulation system is advantaged in its capability in targeting multiple sites simultaneously. Here we propose a strategy that could achieve conditional KO of multiple genes in mouse with Cre recombinase dependent Cas9 expression. By transgenic construction of loxP-stop-loxP (LSL) controlled Cas9 (LSL-Cas9) together with sgRNAs targeting EGFP, we showed that the fluorescence molecule could be eliminated in a Cre-dependent manner. We further verified the efficacy of this novel strategy to target multiple sites by deleting c-Maf and MafB simultaneously in macrophages specifically. Compared to the traditional Cre-flox cKO strategy, this sgRNAs-LSL-Cas9 cKO system is simpler and faster, and would make conditional manipulation of multiple genes feasible.

  15. Metabolic impact of adult-onset, isolated, growth hormone deficiency (AOiGHD due to destruction of pituitary somatotropes.

    Directory of Open Access Journals (Sweden)

    Raul M Luque

    2011-01-01

    Full Text Available Growth hormone (GH inhibits fat accumulation and promotes protein accretion, therefore the fall in GH observed with weight gain and normal aging may contribute to metabolic dysfunction. To directly test this hypothesis a novel mouse model of adult onset-isolated GH deficiency (AOiGHD was generated by cross breeding rat GH promoter-driven Cre recombinase mice (Cre with inducible diphtheria toxin receptor mice (iDTR and treating adult Cre(+/-,iDTR(+/- offspring with DT to selectively destroy the somatotrope population of the anterior pituitary gland, leading to a reduction in circulating GH and IGF-I levels. DT-treated Cre(-/-,iDTR(+/- mice were used as GH-intact controls. AOiGHD improved whole body insulin sensitivity in both low-fat and high-fat fed mice. Consistent with improved insulin sensitivity, indirect calorimetry revealed AOiGHD mice preferentially utilized carbohydrates for energy metabolism, as compared to GH-intact controls. In high-fat, but not low-fat fed AOiGHD mice, fat mass increased, hepatic lipids decreased and glucose clearance and insulin output were impaired. These results suggest the age-related decline in GH helps to preserve systemic insulin sensitivity, and in the context of moderate caloric intake, prevents the deterioration in metabolic function. However, in the context of excess caloric intake, low GH leads to impaired insulin output, and thereby could contribute to the development of diabetes.

  16. Selectable antibiotic resistance marker gene-free transgenic rice harbouring the garlic leaf lectin gene exhibits resistance to sap-sucking planthoppers.

    Science.gov (United States)

    Sengupta, Subhadipa; Chakraborti, Dipankar; Mondal, Hossain A; Das, Sampa

    2010-03-01

    Rice, the major food crop of world is severely affected by homopteran sucking pests. We introduced coding sequence of Allium sativum leaf agglutinin, ASAL, in rice cultivar IR64 to develop sustainable resistance against sap-sucking planthoppers as well as eliminated the selectable antibiotic-resistant marker gene hygromycin phosphotransferase (hpt) exploiting cre/lox site-specific recombination system. An expression vector was constructed containing the coding sequence of ASAL, a potent controlling agent against green leafhoppers (GLH, Nephotettix virescens) and brown planthopper (BPH, Nilaparvata lugens). The selectable marker (hpt) gene cassette was cloned within two lox sites of the same vector. Alongside, another vector was developed with chimeric cre recombinase gene cassette. Reciprocal crosses were performed between three single-copy T(0) plants with ASAL- lox-hpt-lox T-DNA and three single-copy T(0) plants with cre-bar T-DNA. Marker gene excisions were detected in T(1) hybrids through hygromycin sensitivity assay. Molecular analysis of T(1) plants exhibited 27.4% recombination efficiency. T(2) progenies of L03C04(1) hybrid parent showed 25% cre negative ASAL-expressing plants. Northern blot, western blot and ELISA showed significant level of ASAL expression in five marker-free T(2) progeny plants. In planta bioassay of GLH and BPH performed on these T(2) progenies exhibited radical reduction in survivability and fecundity compared with the untransformed control plants.

  17. Ins1 Cre knock-in mice for beta cell-specific gene recombination

    OpenAIRE

    Thorens Bernard; Tarussio David; Maestro Miguel Angel; Maestro Miguel Angel; Rovira Meritxell; Rovira Meritxell; Heikkilä Eija; Ferrer Jorge; Ferrer Jorge; Ferrer Jorge

    2013-01-01

    Aims/hypothesis Pancreatic beta cells play a central role in the control of glucose homeostasis by secreting insulin to stimulate glucose uptake by peripheral tissues. Understanding the molecular mechanisms that control beta cell function and plasticity has critical implications for the pathophysiology and therapy of major forms of diabetes. Selective gene inactivation in pancreatic beta cells, using the Cre-lox system, is a powerful approach to assess the role of particular genes in beta cel...

  18. Recombinase, chromosomal translocations and lymphoid neoplasia: targeting mistakes and repair failures.

    Science.gov (United States)

    Marculescu, Rodrig; Vanura, Katrina; Montpellier, Bertrand; Roulland, Sandrine; Le, Trang; Navarro, Jean-Marc; Jäger, Ulrich; McBlane, Fraser; Nadel, Bertrand

    2006-09-08

    A large number of lymphoid malignancies is characterized by specific chromosomal translocations, which are closely linked to the initial steps of pathogenesis. The hallmark of these translocations is the ectopic activation of a silent proto-oncogene through its relocation at the vicinity of an active regulatory element. Due to the unique feature of lymphoid cells to somatically rearrange and mutate receptor genes, and to the corresponding strong activity of the immune enhancers/promoters at that stage of cell development, B- and T-cell differentiation pathways represent propitious targets for chromosomal translocations and oncogene activation. Recent progress in the understanding of the V(D)J recombination process has allowed a more accurate definition of the translocation mechanisms involved, and has revealed that V(D)J-mediated translocations result both from targeting mistakes of the recombinase, and from illegitimate repair of the V(D)J recombination intermediates. Surprisingly, V(D)J-mediated translocations turn out to be restricted to two specific sub-types of lymphoid malignancies, T-cell acute lymphoblastic leukemias, and a restricted set of mature B-cell Non-Hodgkin's lymphomas.

  19. Endogenous n-3 Polyunsaturated Fatty Acids Delay Progression of Pancreatic Ductal Adenocarcinoma in Fat-1-p48Cre/+-LSL-KrasG12D/+ Mice

    Directory of Open Access Journals (Sweden)

    Altaf Mohammed

    2012-12-01

    Full Text Available Preclinical studies suggest that diets rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs may be beneficial for prevention of pancreatic cancer. Nutritional intervention studies are often complex, and there is no clear evidence, without potential confounding factors, on whether conversion of n-6 PUFAs to n-3 PUFAs in pancreatic tissues would provide protection. Experiments were designed using n-3 fatty acid desaturase (Fat-1 transgenic mice, which can convert n-6 PUFA to n-3 FAs endogenously, to determine the impact of n-3 PUFAs on pancreatic intraepithelial neoplasms (PanINs and their progression to pancreatic ductal adenocarcinoma (PDAC. Six-weekold female p48Cre/+-LSL-KrasG12D/+ andcompoundFat-1-p48Cre/+-LSL-KrasG12D/+ mice were fed (AIN-76A diets containing 10% safflower oil for 35 weeks. Pancreata were evaluated histopathologically for PanINs and PDAC. Results showed a dramatic reduction in incidence of PDAC (84%; P 85%; P < .05–0.01 in pancreas of compound transgenic mice than in those of p48Cre/+-LSL-KrasG12D/+ mice. Molecular analysis of the pancreas showed a significant down-regulation of proliferating cell nuclear antigen, cyclooxygenase-2, 5-lipoxygenase (5-LOX, 5-LOX-activating protein, Bcl-2, and cyclin D1 expression levels in Fat-1-p48Cre/+-LSL-KrasG12D/+ mice compared to p48Cre/+-LSL-KrasG12D/+ mice. These data highlight the promise of dietary n-3 FAs for chemoprevention of pancreatic cancer in high-risk individuals.

  20. Connexin 43-Mediated Astroglial Metabolic Networks Contribute to the Regulation of the Sleep-Wake Cycle.

    Science.gov (United States)

    Clasadonte, Jerome; Scemes, Eliana; Wang, Zhongya; Boison, Detlev; Haydon, Philip G

    2017-09-13

    Astrocytes produce and supply metabolic substrates to neurons through gap junction-mediated astroglial networks. However, the role of astroglial metabolic networks in behavior is unclear. Here, we demonstrate that perturbation of astroglial networks impairs the sleep-wake cycle. Using a conditional Cre-Lox system in mice, we show that knockout of the gap junction subunit connexin 43 in astrocytes throughout the brain causes excessive sleepiness and fragmented wakefulness during the nocturnal active phase. This astrocyte-specific genetic manipulation silenced the wake-promoting orexin neurons located in the lateral hypothalamic area (LHA) by impairing glucose and lactate trafficking through astrocytic networks. This global wakefulness instability was mimicked with viral delivery of Cre recombinase to astrocytes in the LHA and rescued by in vivo injections of lactate. Our findings propose a novel regulatory mechanism critical for maintaining normal daily cycle of wakefulness and involving astrocyte-neuron metabolic interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Permanent genetic access to transiently active neurons via TRAP: targeted recombination in active populations.

    Science.gov (United States)

    Guenthner, Casey J; Miyamichi, Kazunari; Yang, Helen H; Heller, H Craig; Luo, Liqun

    2013-06-05

    Targeting genetically encoded tools for neural circuit dissection to relevant cellular populations is a major challenge in neurobiology. We developed an approach, targeted recombination in active populations (TRAP), to obtain genetic access to neurons that were activated by defined stimuli. This method utilizes mice in which the tamoxifen-dependent recombinase CreER(T2) is expressed in an activity-dependent manner from the loci of the immediate early genes Arc and Fos. Active cells that express CreER(T2) can only undergo recombination when tamoxifen is present, allowing genetic access to neurons that are active during a time window of less than 12 hr. We show that TRAP can provide selective access to neurons activated by specific somatosensory, visual, and auditory stimuli and by experience in a novel environment. When combined with tools for labeling, tracing, recording, and manipulating neurons, TRAP offers a powerful approach for understanding how the brain processes information and generates behavior. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Critical Religious Education (CRE) in Practice: Evaluating the Reception of an Introductory Scheme of Work

    Science.gov (United States)

    Goodman, Angela

    2018-01-01

    Critical Religious Education (CRE) is a contemporary pedagogy of religious education developed by Andrew Wright and various colleagues over the past two decades. There has been widespread academic discourse about the pedagogy in theory but increasingly commentators have called for examples of it in practice. Over the past seven years a writing…

  3. Investigation by CRE into record high electricity prices on Powernext Day-ahead Auction in October and November 2007. Analysis report

    International Nuclear Information System (INIS)

    2008-01-01

    In October and November 2007, electricity prices hit record highs on the Powernext Day-Ahead Auction trading platform. While, during the first nine months of the year, prices for delivery between 6 pm and 8 pm averaged euros 36 /MWh, rising to a maximum of euros 118 /MWh, they spiked at: - euros 1,236 /MWh for delivery on Monday, 29 October 2007 between 6 pm and 7 pm; - euros 2,500 /MWh for delivery on Monday, 12 November 2007 between 8 pm and 9 pm; - euros 1,762 /MWh for delivery on Thursday, 15 November 2007 between 6 pm and 7 pm. Day ahead prices of electricity have a major effect on the procurement costs of suppliers, and consequently on the formation of selling prices to end consumers. Article 28 of French Act No.2000-108 of 10 February 2000 stipulates that CRE 'shall monitor, for electricity and natural gas, all transactions made between suppliers, brokers and producers, all transactions made on the organised markets and cross-border trading. It shall ensure that bids made by suppliers, brokers and producers are consistent with their financial and technical requirements'. Article 33 of the same Act specifies that, 'In performing the tasks entrusted to it, the French Energy Regulatory Commission (CRE) may gather any information it requires from the Ministers for the Economy and for Energy, from public electricity transmission and distribution system operators, from operators of infrastructures for the natural gas transmission and distribution networks and operators of liquefied natural gas facilities, as well as from any other company involved in the electricity and natural gas market. It may also call upon any person whose evidence it deems necessary for the purposes of its investigations'. In this context, and in application of its duty to monitor the electricity wholesale markets, CRE has undertaken an investigation to analyse the mechanisms underlying the formation of such high prices. To this end, CRE gathered information relative to decisions taken by

  4. Cell-type-specific roles for COX-2 in UVB-induced skin cancer

    Science.gov (United States)

    Herschman, Harvey

    2014-01-01

    In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2 flox/flox mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2 flox/flox;K14Cre + mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2 flox/flox;K14Cre + papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2 flox/flox; LysMCre + myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. PMID:24469308

  5. Fibroblast growth factor receptor signaling is essential for normal mammary gland development and stem cell function.

    Science.gov (United States)

    Pond, Adam C; Bin, Xue; Batts, Torey; Roarty, Kevin; Hilsenbeck, Susan; Rosen, Jeffrey M

    2013-01-01

    Fibroblast growth factor (FGF) signaling plays an important role in embryonic stem cells and adult tissue homeostasis, but the function of FGFs in mammary gland stem cells is less well defined. Both FGFR1 and FGFR2 are expressed in basal and luminal mammary epithelial cells (MECs), suggesting that together they might play a role in mammary gland development and stem cell dynamics. Previous studies have demonstrated that the deletion of FGFR2 resulted only in transient developmental defects in branching morphogenesis. Using a conditional deletion strategy, we investigated the consequences of FGFR1 deletion alone and then the simultaneous deletion of both FGFR1 and FGFR2 in the mammary epithelium. FGFR1 deletion using a keratin 14 promoter-driven Cre-recombinase resulted in an early, yet transient delay in development. However, no reduction in functional outgrowth potential was observed following limiting dilution transplantation analysis. In contrast, a significant reduction in outgrowth potential was observed upon the deletion of both FGFR1 and FGFR2 in MECs using adenovirus-Cre. Additionally, using a fluorescent reporter mouse model to monitor Cre-mediated recombination, we observed a competitive disadvantage following transplantation of both FGFR1/R2-null MECs, most prominently in the basal epithelial cells. This correlated with the complete loss of the mammary stem cell repopulating population in the FGFR1/R2-attenuated epithelium. FGFR1/R2-null MECs were partially rescued in chimeric outgrowths containing wild-type MECs, suggesting the potential importance of paracrine mechanisms involved in the maintenance of the basal epithelial stem cells. These studies document the requirement for functional FGFR signaling in mammary stem cells during development. Copyright © 2012 AlphaMed Press.

  6. Cell-Specific Loss of SNAP25 from Cortical Projection Neurons Allows Normal Development but Causes Subsequent Neurodegeneration.

    Science.gov (United States)

    Hoerder-Suabedissen, Anna; Korrell, Kim V; Hayashi, Shuichi; Jeans, Alexander; Ramirez, Denise M O; Grant, Eleanor; Christian, Helen C; Kavalali, Ege T; Wilson, Michael C; Molnár, Zoltán

    2018-05-30

    Synaptosomal associated protein 25 kDa (SNAP25) is an essential component of the SNARE complex regulating synaptic vesicle fusion. SNAP25 deficiency has been implicated in a variety of cognitive disorders. We ablated SNAP25 from selected neuronal populations by generating a transgenic mouse (B6-Snap25tm3mcw (Snap25-flox)) with LoxP sites flanking exon5a/5b. In the presence of Cre-recombinase, Snap25-flox is recombined to a truncated transcript. Evoked synaptic vesicle release is severely reduced in Snap25 conditional knockout (cKO) neurons as shown by live cell imaging of synaptic vesicle fusion and whole cell patch clamp recordings in cultured hippocampal neurons. We studied Snap25 cKO in subsets of cortical projection neurons in vivo (L5-Rbp4-Cre; L6-Ntsr1-Cre; L6b-Drd1a-Cre). cKO neurons develop normal axonal projections, but axons are not maintained appropriately, showing signs of swelling, fragmentation and eventually complete absence. Onset and progression of degeneration are dependent on the neuron type, with L5 cells showing the earliest and most severe axonal loss. Ultrastructural examination revealed that cKO neurites contain autophagosome/lysosome-like structures. Markers of inflammation such as Iba1 and lipofuscin are increased only in adult cKO cortex. Snap25 cKO can provide a model to study genetic interactions with environmental influences in several disorders.

  7. Morphological study of tooth development in podoplanin-deficient mice.

    Directory of Open Access Journals (Sweden)

    Kenyo Takara

    Full Text Available Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

  8. Morphological study of tooth development in podoplanin-deficient mice.

    Science.gov (United States)

    Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

    2017-01-01

    Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone.

  9. Novel migrating mouse neural crest cell assay system utilizing P0-Cre/EGFP fluorescent time-lapse imaging

    Directory of Open Access Journals (Sweden)

    Kawakami Minoru

    2011-11-01

    Full Text Available Abstract Background Neural crest cells (NCCs are embryonic, multipotent stem cells. Their long-range and precision-guided migration is one of their most striking characteristics. We previously reported that P0-Cre/CAG-CAT-lacZ double-transgenic mice showed significant lacZ expression in tissues derived from NCCs. Results In this study, by embedding a P0-Cre/CAG-CAT-EGFP embryo at E9.5 in collagen gel inside a culture glass slide, we were able to keep the embryo developing ex vivo for more than 24 hours; this development was with enough NCC fluorescent signal intensity to enable single-cell resolution analysis, with the accompanying NCC migration potential intact and with the appropriate NCC response to the extracellular signal maintained. By implantation of beads with absorbed platelet-derived growth factor-AA (PDGF-AA, we demonstrated that PDGF-AA acts as an NCC-attractant in embryos. We also performed assays with NCCs isolated from P0-Cre/CAG-CAT-EGFP embryos on culture plates. The neuromediator 5-hydroxytryptamine (5-HT has been known to regulate NCC migration. We newly demonstrated that dopamine, in addition to 5-HT, stimulated NCC migration in vitro. Two NCC populations, with different axial levels of origins, showed unique distribution patterns regarding migration velocity and different dose-response patterns to both 5-HT and dopamine. Conclusions Although avian species predominated over the other species in the NCC study, our novel system should enable us to use mice to assay many different aspects of NCCs in embryos or on culture plates, such as migration, division, differentiation, and apoptosis.

  10. Being a Learner Using Social Media in School: The Case of Space2cre8

    Science.gov (United States)

    Vasbø, Kristin Beate; Silseth, Kenneth; Erstad, Ola

    2014-01-01

    The aim of this article is to gain knowledge about what it means to be a learner using social media in an educational setting. The article presents an ethnographic study of students in a multiethnic community in Oslo who participate in a social networking site called Space2cre8 (S28). In this article, we set out to explore the kind of space for…

  11. Detection and Characterization of Viral Species/Subspecies Using Isothermal Recombinase Polymerase Amplification (RPA) Assays.

    Science.gov (United States)

    Glais, Laurent; Jacquot, Emmanuel

    2015-01-01

    Numerous molecular-based detection protocols include an amplification step of the targeted nucleic acids. This step is important to reach the expected sensitive detection of pathogens in diagnostic procedures. Amplifications of nucleic acid sequences are generally performed, in the presence of appropriate primers, using thermocyclers. However, the time requested to amplify molecular targets and the cost of the thermocycler machines could impair the use of these methods in routine diagnostics. Recombinase polymerase amplification (RPA) technique allows rapid (short-term incubation of sample and primers in an enzymatic mixture) and simple (isothermal) amplification of molecular targets. RPA protocol requires only basic molecular steps such as extraction procedures and agarose gel electrophoresis. Thus, RPA can be considered as an interesting alternative to standard molecular-based diagnostic tools. In this paper, the complete procedures to set up an RPA assay, applied to detection of RNA (Potato virus Y, Potyvirus) and DNA (Wheat dwarf virus, Mastrevirus) viruses, are described. The proposed procedure allows developing species- or subspecies-specific detection assay.

  12. Recombinase polymerase amplification: Emergence as a critical molecular technology for rapid, low-resource diagnostics.

    Science.gov (United States)

    James, Ameh; Macdonald, Joanne

    2015-01-01

    Isothermal molecular diagnostics are bridging the technology gap between traditional diagnostics and polymerase chain reaction-based methods. These new techniques enable timely and accurate testing, especially in settings where there is a lack of infrastructure to support polymerase chain reaction facilities. Despite this, there is a significant lack of uptake of these technologies in developing countries where they are highly needed. Among these novel isothermal technologies, recombinase polymerase amplification (RPA) holds particular potential for use in developing countries. This rapid nucleic acid amplification approach is fast, highly sensitive and specific, and amenable to countries with a high burden of infectious diseases. Implementation of RPA technology in developing countries is critically required to assess limitations and potentials of the diagnosis of infectious disease, and may help identify impediments that prevent adoption of new molecular technologies in low resource- and low skill settings. This review focuses on approaching diagnosis of infectious disease with RPA.

  13. Enhancement of the RAD51 Recombinase Activity by the Tumor Suppressor PALB2

    Energy Technology Data Exchange (ETDEWEB)

    Dray, Eloise; Etchin, Julia; Wiese, Claudia; Saro, Dorina; Williams, Gareth J.; Hammel, Michal; Yu, Xiong; Galkin, Vitold E.; Liu, Dongqing; Tsai, Miaw-Sheue; Sy, Shirley M-H.; Egelman, Edward; Chen, Junjie; Sung, Patrick; Schild, D.

    2010-08-24

    Homologous recombination mediated by the RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-stranded breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2 in the enhancement of RAD51's ability to form the D-loop. We show that PALB2 binds DNA and physically interacts with RAD51. Importantly, while PALB2 alone stimulates D-loop formation, a cooperative effect is seen with RAD51AP1, an enhancer of RAD51. This stimulation stems from PALB2's ability to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results help unveil a multi-faceted role of PALB2 in chromosome damage repair. Since PALB2 mutations can cause breast and other tumors or lead to Fanconi anemia, our findings are important for understanding the mechanism of tumor suppression in humans.

  14. Generation of ERα-floxed and knockout mice using the Cre/LoxP system

    International Nuclear Information System (INIS)

    Antonson, P.; Omoto, Y.; Humire, P.; Gustafsson, J.-Å.

    2012-01-01

    Highlights: ► ERα floxed and knockout mice were generated. ► Disruption of the ERα gene results in sterility in both male and female mice. ► ERα −/− mice have ovaries with hemorrhagic follicles and hypoplastic uterus. ► Female ERα −/− mice develop obesity. -- Abstract: Estrogen receptor alpha (ERα) is a nuclear receptor that regulates a range of physiological processes in response to estrogens. In order to study its biological role, we generated a floxed ERα mouse line that can be used to knock out ERα in selected tissues by using the Cre/LoxP system. In this study, we established a new ERα knockout mouse line by crossing the floxed ERα mice with Cre deleter mice. Here we show that genetic disruption of the ERα gene in all tissues results in sterility in both male and female mice. Histological examination of uterus and ovaries revealed a dramatically atrophic uterus and hemorrhagic cysts in the ovary. These results suggest that infertility in female mice is the result of functional defects of the reproductive tract. Moreover, female knockout mice are hyperglycemic, develop obesity and at the age of 4 months the body weight of these mice was more than 20% higher compared to wild type littermates and this difference increased over time. Our results demonstrate that ERα is necessary for reproductive tract development and has important functions as a regulator of metabolism in females.

  15. Sensitivity of TDF and CRE to variations in exponents of N and T

    International Nuclear Information System (INIS)

    Orton, C.G.

    1976-01-01

    A typical example is given of the calculation by two methods of the value of the radiation dose given in 20 treatments at 5 fractions per week to be equivalent to 6000 rad given in 30 treatments also at 5 fractions per week. The solutions obtained were identical and demonstrated that, in normal clinical practice, whatever values are chosen for the exponents of N and T in the basic NSD equation, the CRE (Kirk, J., Gray, W.M., and Watson, E.R., 1971, Clinical Radiology, vol. 22, 145) and TDF (Orton, C.G., and Ellis, F., 1973, Br. J. Radiol., vol. 46, 529) methods are exactly equivalent. The variations in the values calculated by the TDF method of the dose/fraction in the same example for differing values of the exponents of N and T were typically less than +- 3%, and even for more drastic changes a variation of less than 5% resulted. The TDF and CRE methods are not therefore very sensitive to changes in these exponents. It is emphasized that since CREs are not linearly additive, application of the TDF method greatly reduces the probability of arithmetical error, particularly for more complex treatment regimes. The TDF method should however be applied with great caution if the time, dose or fractionation differ significantly from that used in conventional radiotherapeutic practice, since the theory was based on clinical evidence obtained by retrospective analysis of typical radiotherapy data. (U.K.)

  16. Sensitivity of TDF and CRE to variations in exponents of N and T

    Energy Technology Data Exchange (ETDEWEB)

    Orton, C G [Rhode Island Hospital, Providence (USA). Dept. of Radiation Oncology

    1976-10-01

    A typical example is given of the calculation by two methods of the value of the radiation dose given in 20 treatments at 5 fractions per week to be equivalent to 6000 rad given in 30 treatments also at 5 fractions per week. The solutions obtained were identical and demonstrated that, in normal clinical practice, whatever values are chosen for the exponents of N and T in the basic NSD equation, the CRE (Kirk, J., Gray, W.M., and Watson, E.R., 1971, Clinical Radiology, vol. 22, 145) and TDF (Orton, C.G., and Ellis, F., 1973, Br. J. Radiol., vol. 46, 529) methods are exactly equivalent. The variations in the values calculated by the TDF method of the dose/fraction in the same example for differing values of the exponents of N and T were typically less than +- 3%, and even for more drastic changes a variation of less than 5% resulted. The TDF and CRE methods are not therefore very sensitive to changes in these exponents. It is emphasized that since CREs are not linearly additive, application of the TDF method greatly reduces the probability of arithmetical error, particularly for more complex treatment regimes. The TDF method should however be applied with great caution if the time, dose or fractionation differ significantly from that used in conventional radiotherapeutic practice, since the theory was based on clinical evidence obtained by retrospective analysis of typical radiotherapy data.

  17. Proglucagon Promoter Cre-Mediated AMPK Deletion in Mice Increases Circulating GLP-1 Levels and Oral Glucose Tolerance.

    Directory of Open Access Journals (Sweden)

    Sophie R Sayers

    Full Text Available Enteroendocrine L-cells synthesise and release the gut hormone glucagon-like peptide-1 (GLP-1 in response to food transit. Deletion of the tumour suppressor kinase LKB1 from proglucagon-expressing cells leads to the generation of intestinal polyps but no change in circulating GLP-1 levels. Here, we explore the role of the downstream kinase AMP-activated protein kinase (AMPK in these cells.Loss of AMPK from proglucagon-expressing cells was achieved using a preproglucagon promoter-driven Cre (iGluCre to catalyse recombination of floxed alleles of AMPKα1 and α2. Oral and intraperitoneal glucose tolerance were measured using standard protocols. L-cell mass was measured by immunocytochemistry. Hormone and peptide levels were measured by electrochemical-based luminescence detection or radioimmunoassay.Recombination with iGluCre led to efficient deletion of AMPK from intestinal L- and pancreatic alpha-cells. In contrast to mice rendered null for LKB1 using the same strategy, mice deleted for AMPK displayed an increase (WT: 0.05 ± 0.01, KO: 0.09±0.02%, p<0.01 in L-cell mass and elevated plasma fasting (WT: 5.62 ± 0.800 pg/ml, KO: 14.5 ± 1.870, p<0.01 and fed (WT: 15.7 ± 1.48pg/ml, KO: 22.0 ± 6.62, p<0.01 GLP-1 levels. Oral, but not intraperitoneal, glucose tolerance was significantly improved by AMPK deletion, whilst insulin and glucagon levels were unchanged despite an increase in alpha to beta cell ratio (WT: 0.23 ± 0.02, KO: 0.33 ± 0.03, p<0.01.AMPK restricts L-cell growth and GLP-1 secretion to suppress glucose tolerance. Targeted inhibition of AMPK in L-cells may thus provide a new therapeutic strategy in some forms of type 2 diabetes.

  18. Heterogeneous asymmetric recombinase polymerase amplification (haRPA) for rapid hygiene control of large-volume water samples.

    Science.gov (United States)

    Elsäßer, Dennis; Ho, Johannes; Niessner, Reinhard; Tiehm, Andreas; Seidel, Michael

    2018-04-01

    Hygiene of drinking water is periodically controlled by cultivation and enumeration of indicator bacteria. Rapid and comprehensive measurements of emerging pathogens are of increasing interest to improve drinking water safety. In this study, the feasibility to detect bacteriophage PhiX174 as a potential indicator for virus contamination in large volumes of water is demonstrated. Three consecutive concentration methods (continuous ultrafiltration, monolithic adsorption filtration, and centrifugal ultrafiltration) were combined to concentrate phages stepwise from 1250 L drinking water into 1 mL. Heterogeneous asymmetric recombinase polymerase amplification (haRPA) is applied as rapid detection method. Field measurements were conducted to test the developed system for hygiene online monitoring under realistic conditions. We could show that this system allows the detection of artificial contaminations of bacteriophage PhiX174 in drinking water pipelines. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. K-Ras and β-catenin mutations cooperate with Fgfr3 mutations in mice to promote tumorigenesis in the skin and lung, but not in the bladder

    Directory of Open Access Journals (Sweden)

    Imran Ahmad

    2011-07-01

    The human fibroblast growth factor receptor 3 (FGFR3 gene is frequently mutated in superficial urothelial cell carcinoma (UCC. To test the functional significance of FGFR3 activating mutations as a ‘driver’ of UCC, we targeted the expression of mutated Fgfr3 to the murine urothelium using Cre-loxP recombination driven by the uroplakin II promoter. The introduction of the Fgfr3 mutations resulted in no obvious effect on tumorigenesis up to 18 months of age. Furthermore, even when the Fgfr3 mutations were introduced together with K-Ras or β-catenin (Ctnnb1 activating mutations, no urothelial dysplasia or UCC was observed. Interestingly, however, owing to a sporadic ectopic Cre recombinase expression in the skin and lung of these mice, Fgfr3 mutation caused papilloma and promoted lung tumorigenesis in cooperation with K-Ras and β-catenin activation, respectively. These results indicate that activation of FGFR3 can cooperate with other mutations to drive tumorigenesis in a context-dependent manner, and support the hypothesis that activation of FGFR3 signaling contributes to human cancer.

  20. Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells.

    Science.gov (United States)

    Sato, Hiroshi; Kato, Hiroki; Yamaza, Haruyoshi; Masuda, Keiji; Nguyen, Huong Thi Nguyen; Pham, Thanh Thi Mai; Han, Xu; Hirofuji, Yuta; Nonaka, Kazuaki

    2017-01-01

    Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk) gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV). Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.

  1. Cellular origins of cold-induced brown adipocytes in adult mice.

    Science.gov (United States)

    Lee, Yun-Hee; Petkova, Anelia P; Konkar, Anish A; Granneman, James G

    2015-01-01

    This work investigated how cold stress induces the appearance of brown adipocytes (BAs) in brown and white adipose tissues (WATs) of adult mice. In interscapular brown adipose tissue (iBAT), cold exposure increased proliferation of endothelial cells and interstitial cells expressing platelet-derived growth factor receptor, α polypeptide (PDGFRα) by 3- to 4-fold. Surprisingly, brown adipogenesis and angiogenesis were largely restricted to the dorsal edge of iBAT. Although cold stress did not increase proliferation in inguinal white adipose tissue (ingWAT), the percentage of BAs, defined as multilocular adipocytes that express uncoupling protein 1, rose from undetectable to 30% of total adipocytes. To trace the origins of cold-induced BAs, we genetically tagged PDGFRα(+) cells and adipocytes prior to cold exposure, using Pdgfra-Cre recombinase estrogen receptor T2 fusion protein (CreER(T2)) and adiponectin-CreER(T2), respectively. In iBAT, cold stress triggered the proliferation and differentiation of PDGFRα(+) cells into BAs. In contrast, all newly observed BAs in ingWAT (5207 out of 5207) were derived from unilocular adipocytes tagged by adiponectin-CreER(T2)-mediated recombination. Surgical denervation of iBAT reduced cold-induced brown adipogenesis by >85%, whereas infusion of norepinephrine (NE) mimicked the effects of cold in warm-adapted mice. NE-induced de novo brown adipogenesis in iBAT was eliminated in mice lacking β1-adrenergic receptors. These observations identify a novel tissue niche for brown adipogenesis in iBAT and further define depot-specific mechanisms of BA recruitment. © FASEB.

  2. Ablation of kappa-opioid receptors from brain dopamine neurons has anxiolytic-like effects and enhances cocaine-induced plasticity.

    Science.gov (United States)

    Van't Veer, Ashlee; Bechtholt, Anita J; Onvani, Sara; Potter, David; Wang, Yujun; Liu-Chen, Lee-Yuan; Schütz, Günther; Chartoff, Elena H; Rudolph, Uwe; Cohen, Bruce M; Carlezon, William A

    2013-07-01

    Brain kappa-opioid receptors (KORs) are implicated in states of motivation and emotion. Activation of KORs negatively regulates mesolimbic dopamine (DA) neurons, and KOR agonists produce depressive-like behavioral effects. To further evaluate how KOR function affects behavior, we developed mutant mice in which exon 3 of the KOR gene (Oprk1) was flanked with Cre-lox recombination (loxP) sites. By breeding these mice with lines that express Cre-recombinase (Cre) in early embryogenesis (EIIa-Cre) or only in DA neurons (dopamine transporter (DAT)-Cre), we developed constitutive KOR knockouts (KOR(-/-)) and conditional knockouts that lack KORs in DA-containing neurons (DAT-KOR(lox/lox)). Autoradiography demonstrated complete ablation of KOR binding in the KOR(-/-) mutants, and reduced binding in the DAT-KOR(lox/lox) mutants. Quantitative reverse transcription PCR (qPCR) studies confirmed that KOR mRNA is undetectable in the constitutive mutants and reduced in the midbrain DA systems of the conditional mutants. Behavioral characterization demonstrated that these mutant lines do not differ from controls in metrics, including hearing, vision, weight, and locomotor activity. Whereas KOR(-/-) mice appeared normal in the open field and light/dark box tests, DAT-KOR(lox/lox) mice showed reduced anxiety-like behavior, an effect that is broadly consistent with previously reported effects of KOR antagonists. Sensitization to the locomotor-stimulating effects of cocaine appeared normal in KOR(-/-) mutants, but was exaggerated in DAT-KOR(lox/lox) mutants. Increased sensitivity to cocaine in the DAT-KOR(lox/lox) mutants is consistent with a role for KORs in negative regulation of DA function, whereas the lack of differences in the KOR(-/-) mutants suggests compensatory adaptations after constitutive receptor ablation. These mouse lines may be useful in future studies of KOR function.

  3. Constitutive stimulatory G protein activity in limb mesenchyme impairs bone growth.

    Science.gov (United States)

    Karaca, Anara; Malladi, Vijayram Reddy; Zhu, Yan; Tafaj, Olta; Paltrinieri, Elena; Wu, Joy Y; He, Qing; Bastepe, Murat

    2018-05-01

    GNAS mutations leading to constitutively active stimulatory G protein alpha-subunit (Gsα) cause different tumors, fibrous dysplasia of bone, and McCune-Albright syndrome, which are typically not associated with short stature. Enhanced signaling of the parathyroid hormone/parathyroid hormone-related peptide receptor, which couples to multiple G proteins including Gsα, leads to short bones with delayed endochondral ossification. It has remained unknown whether constitutive Gsα activity also impairs bone growth. Here we generated mice expressing a constitutively active Gsα mutant (Gsα-R201H) conditionally upon Cre recombinase (cGsα R201H mice). Gsα-R201H was expressed in cultured bone marrow stromal cells from cGsα R201H mice upon adenoviral-Cre transduction. When crossed with mice in which Cre is expressed in a tamoxifen-regulatable fashion (CAGGCre-ER™), tamoxifen injection resulted in mosaic expression of the transgene in double mutant offspring. We then crossed the cGsα R201H mice with Prx1-Cre mice, in which Cre is expressed in early limb-bud mesenchyme. The double mutant offspring displayed short limbs at birth, with narrow hypertrophic chondrocyte zones in growth plates and delayed formation of secondary ossification center. Consistent with enhanced Gsα signaling, bone marrow stromal cells from these mice demonstrated increased levels of c-fos mRNA. Our findings indicate that constitutive Gsα activity during limb development disrupts endochondral ossification and bone growth. Given that Gsα haploinsufficiency also leads to short bones, as in patients with Albright's hereditary osteodystrophy, these results suggest that a tight control of Gsα activity is essential for normal growth plate physiology. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Generation of an allelic series of knock-in mice using recombinase-mediated cassette exchange (RMCE).

    Science.gov (United States)

    Roebroek, Anton J M; Van Gool, Bart

    2014-01-01

    Molecular genetic strategies applying embryonic stem cell (ES cell) technologies to study the function of a gene in mice or to generate a mouse model for a human disease are continuously under development. Next to (conditional) inactivation of genes the application and importance of approaches to generate knock-in mutations are increasing. In this chapter the principle and application of recombinase-mediated cassette exchange (RMCE) are discussed as being a new emerging knock-in strategy, which enables easy generation of a series of different knock-in mutations within one gene. An RMCE protocol, which was used to generate a series of different knock-in mutations in the Lrp1 gene of ES cells, is described in detail as an example of how RMCE can be used to generate highly efficiently an allelic series of differently modified ES cell clones from a parental modified ES cell clone. Subsequently the differently modified ES cell clones can be used to generate an allelic series of mutant knock-in mice.

  5. Msh2 acts in medium-spiny striatal neurons as an enhancer of CAG instability and mutant huntingtin phenotypes in Huntington's disease knock-in mice.

    Directory of Open Access Journals (Sweden)

    Marina Kovalenko

    Full Text Available The CAG trinucleotide repeat mutation in the Huntington's disease gene (HTT exhibits age-dependent tissue-specific expansion that correlates with disease onset in patients, implicating somatic expansion as a disease modifier and potential therapeutic target. Somatic HTT CAG expansion is critically dependent on proteins in the mismatch repair (MMR pathway. To gain further insight into mechanisms of somatic expansion and the relationship of somatic expansion to the disease process in selectively vulnerable MSNs we have crossed HTT CAG knock-in mice (HdhQ111 with mice carrying a conditional (floxed Msh2 allele and D9-Cre transgenic mice, in which Cre recombinase is expressed specifically in MSNs within the striatum. Deletion of Msh2 in MSNs eliminated Msh2 protein in those neurons. We demonstrate that MSN-specific deletion of Msh2 was sufficient to eliminate the vast majority of striatal HTT CAG expansions in HdhQ111 mice. Furthermore, MSN-specific deletion of Msh2 modified two mutant huntingtin phenotypes: the early nuclear localization of diffusely immunostaining mutant huntingtin was slowed; and the later development of intranuclear huntingtin inclusions was dramatically inhibited. Therefore, Msh2 acts within MSNs as a genetic enhancer both of somatic HTT CAG expansions and of HTT CAG-dependent phenotypes in mice. These data suggest that the selective vulnerability of MSNs may be at least in part contributed by the propensity for somatic expansion in these neurons, and imply that intervening in the expansion process is likely to have therapeutic benefit.

  6. Exploiting CReP for Knowledge Retrieval and Use in Complex Domains

    Science.gov (United States)

    Manenti, Lorenza; Sartori, Fabio

    Case Based Reasoning (CBR) is a Knowledge Management approach that consists in the development of decision support systems where problem are solved by analogy with similar problem solved in the past. In this way, the system supports users in finding solutions without starting from scratch. CBR has become a very important research topic in Artificial Intelligence, with the definition of methodologies and architectural patterns for supporting developers in the design and implementation of case-based systems. The paper presents one of this frameworks, namely CReP, an on-going research project of the Artificial Intelligence Laboratory (L.Int.Ar.) of University of Milan-Bicocca, focusing on the integration between CBR paradigm and metadata approach to obtain domain-independent case structure and retrieval algorithm definition.

  7. Structure of a filament of stacked octamers of human DMC1 recombinase

    International Nuclear Information System (INIS)

    Du, Liqin; Luo, Yu

    2013-01-01

    Octameric rings of DMC1 stacked into filaments in the crystal. Similar DMC1–DNA filaments have been observed previously using electron microscopy. Eukaryal DMC1 proteins play a central role in homologous recombination in meiosis by assembling at the sites of programmed DNA double-strand breaks and carrying out a search for allelic DNA sequences located on homologous chromatids. They are close homologs of eukaryal Rad51 and archaeal RadA proteins and are remote homologs of bacterial RecA proteins. These recombinases (also called DNA strand-exchange proteins) promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. An octameric form of a truncated human DMC1 devoid of its small N-terminal domain (residues 1–83) has been crystallized. The structure of the truncated DMC1 octamer is similar to that of the previously reported full-length DMC1 octamer, which has disordered N-terminal domains. In each protomer, only the ATP cap regions (Asp317–Glu323) show a noticeable conformational difference. The truncated DMC1 octamers further stack with alternate polarity into a filament. Similar filamentous assemblies of DMC1 have been observed to form on DNA by electron microscopy

  8. Rapid and sensitive detection of canine distemper virus by real-time reverse transcription recombinase polymerase amplification.

    Science.gov (United States)

    Wang, Jianchang; Wang, Jinfeng; Li, Ruiwen; Liu, Libing; Yuan, Wanzhe

    2017-08-15

    Canine distemper, caused by Canine distemper virus (CDV), is a highly contagious and fatal systemic disease in free-living and captive carnivores worldwide. Recombinase polymerase amplification (RPA), as an isothermal gene amplification technique, has been explored for the molecular detection of diverse pathogens. A real-time reverse transcription RPA (RT-RPA) assay for the detection of canine distemper virus (CDV) using primers and exo probe targeting the CDV nucleocapsid protein gene was developed. A series of other viruses were tested by the RT-RPA.Thirty-two field samples were further tested by RT-RPA, and the resuts were compared with those obtained by the real-time RT-PCR. The RT-RPA assay was performed successfully at 40 °C, and the results were obtained within 3 min-12 min. The assay could detect CDV, but did not show cross-detection of canine parvovirus-2 (CPV-2), canine coronavirus (CCoV), canine parainfluenza virus (CPIV), pseudorabies virus (PRV) or Newcastle disease virus (NDV), demonstrating high specificity. The analytical sensitivity of RT-RPA was 31.8 copies in vitro transcribed CDV RNA, which is 10 times lower than the real-time RT-PCR. The assay performance was validated by testing 32 field samples and compared to real-time RT-PCR. The results indicated an excellent correlation between RT-RPA and a reference real-time RT-PCR method. Both assays provided the same results, and R 2 value of the positive results was 0.947. The results demonstrated that the RT-RPA assay offers an alternative tool for simple, rapid, and reliable detection of CDV both in the laboratory and point-of-care facility, especially in the resource-limited settings.

  9. Creating Transgenic shRNA Mice by Recombinase-Mediated Cassette Exchange

    Science.gov (United States)

    Premsrirut, Prem K.; Dow, Lukas E.; Park, Youngkyu; Hannon, Gregory J.; Lowe, Scott W.

    2014-01-01

    RNA interference (RNAi) enables sequence-specific, experimentally induced silencing of virtually any gene by tapping into innate regulatory mechanisms that are conserved among most eukaryotes. The principles that enable transgenic RNAi in cell lines can also be used to create transgenic animals, which express short-hairpin RNAs (shRNAs) in a regulated or tissue-specific fashion. However, RNAi in transgenic animals is somewhat more challenging than RNAi in cultured cells. The activities of promoters that are commonly used for shRNA expression in cell culture can vary enormously in different tissues, and founder lines also typically vary in transgene expression due to the effects of their single integration sites. There are many ways to produce mice carrying shRNA transgenes and the method described here uses recombinase-mediated cassette exchange (RMCE). RMCE permits insertion of the shRNA transgene into a well-characterized locus that gives reproducible and predictable expression in each founder and enhances the probability of potent expression in many cell types. This procedure is more involved and complex than simple pronuclear injection, but if even a few shRNA mice are envisioned, for example, to probe the functions of several genes, the effort of setting up the processes outlined below are well worthwhile. Note that when creating a transgenic mouse, one should take care to use the most potent shRNA possible. As a rule of thumb, the sequence chosen should provide >90% knockdown when introduced into cultured cells at single copy (e.g., on retroviral infection at a multiplicity of ≤0.3). PMID:24003198

  10. Mechanosensory and ATP Release Deficits following Keratin14-Cre-Mediated TRPA1 Deletion Despite Absence of TRPA1 in Murine Keratinocytes.

    Directory of Open Access Journals (Sweden)

    Katherine J Zappia

    Full Text Available Keratinocytes are the first cells that come into direct contact with external tactile stimuli; however, their role in touch transduction in vivo is not clear. The ion channel Transient Receptor Potential Ankyrin 1 (TRPA1 is essential for some mechanically-gated currents in sensory neurons, amplifies mechanical responses after inflammation, and has been reported to be expressed in human and mouse skin. Other reports have not detected Trpa1 mRNA transcripts in human or mouse epidermis. Therefore, we set out to determine whether selective deletion of Trpa1 from keratinocytes would impact mechanosensation. We generated K14Cre-Trpa1fl/fl mice lacking TRPA1 in K14-expressing cells, including keratinocytes. Surprisingly, Trpa1 transcripts were very poorly detected in epidermis of these mice or in controls, and detection was minimal enough to preclude observation of Trpa1 mRNA knockdown in the K14Cre-Trpa1fl/fl mice. Unexpectedly, these K14Cre-Trpa1fl/fl mice nonetheless exhibited a pronounced deficit in mechanosensitivity at the behavioral and primary afferent levels, and decreased mechanically-evoked ATP release from skin. Overall, while these data suggest that the intended targeted deletion of Trpa1 from keratin 14-expressing cells of the epidermis induces functional deficits in mechanotransduction and ATP release, these deficits are in fact likely due to factors other than reduction of Trpa1 expression in adult mouse keratinocytes because they express very little, if any, Trpa1.

  11. Conserved amino acid motifs from the novel Piv/MooV family of transposases and site-specific recombinases are required for catalysis of DNA inversion by Piv.

    Science.gov (United States)

    Tobiason, D M; Buchner, J M; Thiel, W H; Gernert, K M; Karls, A C

    2001-02-01

    Piv, a site-specific invertase from Moraxella lacunata, exhibits amino acid homology with the transposases of the IS110/IS492 family of insertion elements. The functions of conserved amino acid motifs that define this novel family of both transposases and site-specific recombinases (Piv/MooV family) were examined by mutagenesis of fully conserved amino acids within each motif in Piv. All Piv mutants altered in conserved residues were defective for in vivo inversion of the M. lacunata invertible DNA segment, but competent for in vivo binding to Piv DNA recognition sequences. Although the primary amino acid sequences of the Piv/MooV recombinases do not contain a conserved DDE motif, which defines the retroviral integrase/transposase (IN/Tnps) family, the predicted secondary structural elements of Piv align well with those of the IN/Tnps for which crystal structures have been determined. Molecular modelling of Piv based on these alignments predicts that E59, conserved as either E or D in the Piv/MooV family, forms a catalytic pocket with the conserved D9 and D101 residues. Analysis of Piv E59G confirms a role for E59 in catalysis of inversion. These results suggest that Piv and the related IS110/IS492 transposases mediate DNA recombination by a common mechanism involving a catalytic DED or DDD motif.

  12. Generation of ER{alpha}-floxed and knockout mice using the Cre/LoxP system

    Energy Technology Data Exchange (ETDEWEB)

    Antonson, P., E-mail: per.antonson@ki.se [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Omoto, Y.; Humire, P. [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Gustafsson, J.-A. [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204 (United States)

    2012-08-10

    Highlights: Black-Right-Pointing-Pointer ER{alpha} floxed and knockout mice were generated. Black-Right-Pointing-Pointer Disruption of the ER{alpha} gene results in sterility in both male and female mice. Black-Right-Pointing-Pointer ER{alpha}{sup -/-} mice have ovaries with hemorrhagic follicles and hypoplastic uterus. Black-Right-Pointing-Pointer Female ER{alpha}{sup -/-} mice develop obesity. -- Abstract: Estrogen receptor alpha (ER{alpha}) is a nuclear receptor that regulates a range of physiological processes in response to estrogens. In order to study its biological role, we generated a floxed ER{alpha} mouse line that can be used to knock out ER{alpha} in selected tissues by using the Cre/LoxP system. In this study, we established a new ER{alpha} knockout mouse line by crossing the floxed ER{alpha} mice with Cre deleter mice. Here we show that genetic disruption of the ER{alpha} gene in all tissues results in sterility in both male and female mice. Histological examination of uterus and ovaries revealed a dramatically atrophic uterus and hemorrhagic cysts in the ovary. These results suggest that infertility in female mice is the result of functional defects of the reproductive tract. Moreover, female knockout mice are hyperglycemic, develop obesity and at the age of 4 months the body weight of these mice was more than 20% higher compared to wild type littermates and this difference increased over time. Our results demonstrate that ER{alpha} is necessary for reproductive tract development and has important functions as a regulator of metabolism in females.

  13. An AAV9 coding for frataxin clearly improved the symptoms and prolonged the life of Friedreich ataxia mouse models

    Directory of Open Access Journals (Sweden)

    Catherine Gérard

    2014-01-01

    Full Text Available Friedreich ataxia (FRDA is a genetic disease due to increased repeats of the GAA trinucleotide in intron 1 of the frataxin gene. This mutation leads to a reduced expression of frataxin. We have produced an adeno-associated virus (AAV9 coding for human frataxin (AAV9-hFXN. This AAV was delivered by intraperitoneal (IP injection to young conditionally knockout mice in which the frataxin gene had been knocked-out in some tissues during embryogenesis by breeding them with mice expressing the Cre recombinase gene under the muscle creatine kinase (MCK or the neuron-specific enolase (NSE promoter. In the first part of the study, different doses of virus were tested from 6 × 1011 v.p. to 6 × 109 v.p. in NSE-cre mice and all leading to an increase in life spent of the mice. The higher and the lower dose were also tested in MCK-cre mice. A single administration of the AAV9-hFXN at 6 × 1011 v.p. more than doubled the life of these mice. In fact the MCK-cre mice treated with the AAV9-hFXN were sacrificed for further molecular investigations at the age of 29 weeks without apparent symptoms. Echography analysis of the heart function clearly indicated that the cardiac systolic function was better preserved in the mice that received 6 × 1011 v.p. of AAV9-hFXN. The human frataxin protein was detected by ELISA in the heart, brain, muscles, kidney, and liver with the higher dose of virus in both mouse models. Thus, gene therapy with an AAV9-hFXN is a potential treatment of FRDA.

  14. Neural crest contribution to lingual mesenchyme, epithelium and developing taste papillae and taste buds.

    Science.gov (United States)

    Liu, Hong-Xiang; Komatsu, Yoshihiro; Mishina, Yuji; Mistretta, Charlotte M

    2012-08-15

    The epithelium of mammalian tongue hosts most of the taste buds that transduce gustatory stimuli into neural signals. In the field of taste biology, taste bud cells have been described as arising from "local epithelium", in distinction from many other receptor organs that are derived from neurogenic ectoderm including neural crest (NC). In fact, contribution of NC to both epithelium and mesenchyme in the developing tongue is not fully understood. In the present study we used two independent, well-characterized mouse lines, Wnt1-Cre and P0-Cre that express Cre recombinase in a NC-specific manner, in combination with two Cre reporter mouse lines, R26R and ZEG, and demonstrate a contribution of NC-derived cells to both tongue mesenchyme and epithelium including taste papillae and taste buds. In tongue mesenchyme, distribution of NC-derived cells is in close association with taste papillae. In tongue epithelium, labeled cells are observed in an initial scattered distribution and progress to a clustered pattern between papillae, and within papillae and early taste buds. This provides evidence for a contribution of NC to lingual epithelium. Together with previous reports for the origin of taste bud cells from local epithelium in postnatal mouse, we propose that NC cells migrate into and reside in the epithelium of the tongue primordium at an early embryonic stage, acquire epithelial cell phenotypes, and undergo cell proliferation and differentiation that is involved in the development of taste papillae and taste buds. Our findings lead to a new concept about derivation of taste bud cells that include a NC origin. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Establishment of recombinase polymerase amplification assay for five hemorrhagic fever-related viruses

    Directory of Open Access Journals (Sweden)

    Xue-feng CAO

    2017-08-01

    Full Text Available Objective To establish a one-step recombinase polymerase amplification (RPA method for pathogen screening and rapid detection in the field targeting for five hemorrhagic fever related viruses (Zaire ebola virus, Sudan ebola virus, Marburg virus, Lassa virus and Yellow fever virus. Methods The specific nucleic acid (NA fragments of each virus were selected as target genes by genome sequence analysis, and the primers and probes for RPA assays were designed according to the sequence. A series of diluted template genes were used for RPA detection to determine the sensitivity. The hemorrhagic fever-related viral nucleic acids were used for RPA detection to determine the specificity. The amplification experiments were carried out at different temperature ranging from 37℃ to 42℃ to validate the reaction temperature range. Results The RPA reaction systems of the five hemorrhagic fever viruses could effectively amplify the target genes, the sensitivities were between 1.5×102 and 1.5×103 copies. No cross reactions existed with the other hemorrhagic fever-related viral genes. Meanwhile, RPA assay could effectively amplify the target genes at 37-42℃. Conclusion The isothermal RPA assays of five hemorrhagic fever viruses are established, which may amply target genes fast and react at a wide temperature range, and be potentially useful for in field pathogens detection. DOI: 10.11855/j.issn.0577-7402.2017.06.09

  16. Recombinase Polymerase Amplification Assay for Rapid Diagnostics of Dengue Infection.

    Directory of Open Access Journals (Sweden)

    Ahmed Abd El Wahed

    Full Text Available Over 2.5 billion people are exposed to the risk of contracting dengue fever (DF. Early diagnosis of DF helps to diminish its burden on public health. Real-time reverse transcription polymerase amplification assays (RT-PCR are the standard method for molecular detection of the dengue virus (DENV. Real-time RT-PCR analysis is not suitable for on-site screening since mobile devices are large, expensive, and complex. In this study, two RT-recombinase polymerase amplification (RT-RPA assays were developed to detect DENV1-4.Using two quantitative RNA molecular standards, the analytical sensitivity of a RT-RPA targeting the 3´non-translated region of DENV1-4 was found to range from 14 (DENV4 to 241 (DENV1-3 RNA molecules detected. The assay was specific and did not cross detect other Flaviviruses. The RT-RPA assay was tested in a mobile laboratory combining magnetic-bead based total nucleic acid extraction and a portable detection device in Kedougou (Senegal and in Bangkok (Thailand. In Kedougou, the RT-RPA was operated at an ambient temperature of 38 °C with auxiliary electricity tapped from a motor vehicle and yielded a clinical sensitivity and specificity of 98% (n=31 and 100% (n=23, respectively. While in the field trial in Bangkok, the clinical sensitivity and specificity were 72% (n=90 and 100%(n=41, respectively.During the first 5 days of infection, the developed DENV1-4 RT-RPA assays constitute a suitable accurate and rapid assay for DENV diagnosis. Moreover, the use of a portable fluorescence-reading device broadens its application potential to the point-of-care for outbreak investigations.

  17. Site-specific recombination in the chicken genome using Flipase recombinase-mediated cassette exchange.

    Science.gov (United States)

    Lee, Hong Jo; Lee, Hyung Chul; Kim, Young Min; Hwang, Young Sun; Park, Young Hyun; Park, Tae Sub; Han, Jae Yong

    2016-02-01

    Targeted genome recombination has been applied in diverse research fields and has a wide range of possible applications. In particular, the discovery of specific loci in the genome that support robust and ubiquitous expression of integrated genes and the development of genome-editing technology have facilitated rapid advances in various scientific areas. In this study, we produced transgenic (TG) chickens that can induce recombinase-mediated gene cassette exchange (RMCE), one of the site-specific recombination technologies, and confirmed RMCE in TG chicken-derived cells. As a result, we established TG chicken lines that have, Flipase (Flp) recognition target (FRT) pairs in the chicken genome, mediated by piggyBac transposition. The transgene integration patterns were diverse in each TG chicken line, and the integration diversity resulted in diverse levels of expression of exogenous genes in each tissue of the TG chickens. In addition, the replaced gene cassette was expressed successfully and maintained by RMCE in the FRT predominant loci of TG chicken-derived cells. These results indicate that targeted genome recombination technology with RMCE could be adaptable to TG chicken models and that the technology would be applicable to specific gene regulation by cis-element insertion and customized expression of functional proteins at predicted levels without epigenetic influence. © FASEB.

  18. The electricity bill may rise by 30% between now and 2017, according to the CRE

    International Nuclear Information System (INIS)

    Anon.

    2013-01-01

    The CRE (French Regulatory Commission for Electricity) expects a rise of 30% in the electricity price for households in the next five years in France, the rise would only be of 16% for enterprises. The study shows that one third of this rise is due to the contribution to the public service of electricity whose main purpose is to finance the development of renewable energies. The rise will also cover the investments that have to be made in the power grid and in the means of production of electricity. (A.C.)

  19. Engineering of Systematic Elimination of a Targeted Chromosome in Human Cells

    Directory of Open Access Journals (Sweden)

    Hiroshi Sato

    2017-01-01

    Full Text Available Embryonic trisomy leads to abortion or congenital genetic disorders in humans. The most common autosomal chromosome abnormalities are trisomy of chromosomes 13, 18, and 21. Although alteration of gene dosage is thought to contribute to disorders caused by extra copies of chromosomes, genes associated with specific disease phenotypes remain unclear. To generate a normal cell from a trisomic cell as a means of etiological analysis or candidate therapy for trisomy syndromes, we developed a system to eliminate a targeted chromosome from human cells. Chromosome 21 was targeted by integration of a DNA cassette in HeLa cells that harbored three copies of chromosome 21. The DNA cassette included two inverted loxP sites and a herpes simplex virus thymidine kinase (HSV-tk gene. This system causes missegregation of chromosome 21 after expression of Cre recombinase and subsequently enables the selection of cells lacking the chromosome by culturing in a medium that includes ganciclovir (GCV. Cells harboring only two copies of chromosome 21 were efficiently induced by transfection of a Cre expression vector, indicating that this approach is useful for eliminating a targeted chromosome.

  20. Scap is required for sterol synthesis and crypt growth in intestinal mucosa.

    Science.gov (United States)

    McFarlane, Matthew R; Cantoria, Mary Jo; Linden, Albert G; January, Brandon A; Liang, Guosheng; Engelking, Luke J

    2015-08-01

    SREBP cleavage-activating protein (Scap) is an endoplasmic reticulum membrane protein required for cleavage and activation of sterol regulatory element-binding proteins (SREBPs), which activate the transcription of genes in sterol and fatty acid biosynthesis. Liver-specific loss of Scap is well tolerated; hepatic synthesis of sterols and fatty acids is reduced, but mice are otherwise healthy. To determine whether Scap loss is tolerated in the intestine, we generated a mouse model (Vil-Scap(-)) in which tamoxifen-inducible Cre-ER(T2), a fusion protein of Cre recombinase with a mutated ligand binding domain of the human estrogen receptor, ablates Scap in intestinal mucosa. After 4 days of tamoxifen, Vil-Scap(-) mice succumb with a severe enteropathy and near-complete collapse of intestinal mucosa. Organoids grown ex vivo from intestinal crypts of Vil-Scap(-) mice are readily killed when Scap is deleted by 4-hydroxytamoxifen. Death is prevented when culture medium is supplemented with cholesterol and oleate. These data show that, unlike the liver, the intestine requires Scap to sustain tissue integrity by maintaining the high levels of lipid synthesis necessary for proliferation of intestinal crypts. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

  1. Mast cells are dispensable for normal and activin-promoted wound healing and skin carcinogenesis.

    Science.gov (United States)

    Antsiferova, Maria; Martin, Caroline; Huber, Marcel; Feyerabend, Thorsten B; Förster, Anja; Hartmann, Karin; Rodewald, Hans-Reimer; Hohl, Daniel; Werner, Sabine

    2013-12-15

    The growth and differentiation factor activin A is a key regulator of tissue repair, inflammation, fibrosis, and tumorigenesis. However, the cellular targets, which mediate the different activin functions, are still largely unknown. In this study, we show that activin increases the number of mature mast cells in mouse skin in vivo. To determine the relevance of this finding for wound healing and skin carcinogenesis, we mated activin transgenic mice with CreMaster mice, which are characterized by Cre recombinase-mediated mast cell eradication. Using single- and double-mutant mice, we show that loss of mast cells neither affected the stimulatory effect of overexpressed activin on granulation tissue formation and reepithelialization of skin wounds nor its protumorigenic activity in a model of chemically induced skin carcinogenesis. Furthermore, mast cell deficiency did not alter wounding-induced inflammation and new tissue formation or chemically induced angiogenesis and tumorigenesis in mice with normal activin levels. These findings reveal that mast cells are not major targets of activin during wound healing and skin cancer development and also argue against nonredundant functions of mast cells in wound healing and skin carcinogenesis in general.

  2. Dissection of the Mouse Pancreas for Histological Analysis and Metabolic Profiling.

    Science.gov (United States)

    Veite-Schmahl, Michelle J; Regan, Daniel P; Rivers, Adam C; Nowatzke, Joseph F; Kennedy, Michael A

    2017-08-19

    We have been investigating the pancreas specific transcription factor, 1a cre-recombinase; lox-stop-lox- Kristen rat sarcoma, glycine to aspartic acid at the 12 codon (Ptf1a cre/+ ;LSL-Kras G12D/+ ) mouse strain as a model of human pancreatic cancer. The goal of our current studies is to identify novel metabolic biomarkers of pancreatic cancer progression. We have performed metabolic profiling of urine, feces, blood, and pancreas tissue extracts, as well as histological analyses of the pancreas to stage the cancer progression. The mouse pancreas is not a well-defined solid organ like in humans, but rather is a diffusely distributed soft tissue that is not easily identified by individuals unfamiliar with mouse internal anatomy or by individuals that have little or no experience performing mouse organ dissections. The purpose of this article is to provide a detailed step-wise visual demonstration to guide novices in the removal of the mouse pancreas by dissection. This article should be especially valuable to students and investigators new to research that requires harvesting of the mouse pancreas by dissection for metabolic profiling or histological analyses.

  3. Acute Vhl gene inactivation induces cardiac HIF-dependent erythropoietin gene expression.

    Directory of Open Access Journals (Sweden)

    Marta Miró-Murillo

    Full Text Available Von Hippel Lindau (Vhl gene inactivation results in embryonic lethality. The consequences of its inactivation in adult mice, and of the ensuing activation of the hypoxia-inducible factors (HIFs, have been explored mainly in a tissue-specific manner. This mid-gestation lethality can be also circumvented by using a floxed Vhl allele in combination with an ubiquitous tamoxifen-inducible recombinase Cre-ER(T2. Here, we characterize a widespread reduction in Vhl gene expression in Vhl(floxed-UBC-Cre-ER(T2 adult mice after dietary tamoxifen administration, a convenient route of administration that has yet to be fully characterized for global gene inactivation. Vhl gene inactivation rapidly resulted in a marked splenomegaly and skin erythema, accompanied by renal and hepatic induction of the erythropoietin (Epo gene, indicative of the in vivo activation of the oxygen sensing HIF pathway. We show that acute Vhl gene inactivation also induced Epo gene expression in the heart, revealing cardiac tissue to be an extra-renal source of EPO. Indeed, primary cardiomyocytes and HL-1 cardiac cells both induce Epo gene expression when exposed to low O(2 tension in a HIF-dependent manner. Thus, as well as demonstrating the potential of dietary tamoxifen administration for gene inactivation studies in UBC-Cre-ER(T2 mouse lines, this data provides evidence of a cardiac oxygen-sensing VHL/HIF/EPO pathway in adult mice.

  4. Identification of G Protein-Coupled Receptors (GPCRs in Primary Cilia and Their Possible Involvement in Body Weight Control.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Omori

    Full Text Available Primary cilia are sensory organelles that harbor various receptors such as G protein-coupled receptors (GPCRs. We analyzed subcellular localization of 138 non-odorant GPCRs. We transfected GPCR expression vectors into NIH3T3 cells, induced ciliogenesis by serum starvation, and observed subcellular localization of GPCRs by immunofluorescent staining. We found that several GPCRs whose ligands are involved in feeding behavior, including prolactin-releasing hormone receptor (PRLHR, neuropeptide FF receptor 1 (NPFFR1, and neuromedin U receptor 1 (NMUR1, localized to the primary cilia. In addition, we found that a short form of dopamine receptor D2 (DRD2S is efficiently transported to the primary cilia, while a long form of dopamine receptor D2 (DRD2L is rarely transported to the primary cilia. Using an anti-Prlhr antibody, we found that Prlhr localized to the cilia on the surface of the third ventricle in the vicinity of the hypothalamic periventricular nucleus. We generated the Npy2r-Cre transgenic mouse line in which Cre-recombinase is expressed under the control of the promoter of Npy2r encoding a ciliary GPCR. By mating Npy2r-Cre mice with Ift80 flox mice, we generated Ift80 conditional knockout (CKO mice in which Npy2r-positive cilia were diminished in number. We found that Ift80 CKO mice exhibited a body weight increase. Our results suggest that Npy2r-positive cilia are important for body weight control.

  5. Identification of G Protein-Coupled Receptors (GPCRs) in Primary Cilia and Their Possible Involvement in Body Weight Control.

    Science.gov (United States)

    Omori, Yoshihiro; Chaya, Taro; Yoshida, Satoyo; Irie, Shoichi; Tsujii, Toshinori; Furukawa, Takahisa

    2015-01-01

    Primary cilia are sensory organelles that harbor various receptors such as G protein-coupled receptors (GPCRs). We analyzed subcellular localization of 138 non-odorant GPCRs. We transfected GPCR expression vectors into NIH3T3 cells, induced ciliogenesis by serum starvation, and observed subcellular localization of GPCRs by immunofluorescent staining. We found that several GPCRs whose ligands are involved in feeding behavior, including prolactin-releasing hormone receptor (PRLHR), neuropeptide FF receptor 1 (NPFFR1), and neuromedin U receptor 1 (NMUR1), localized to the primary cilia. In addition, we found that a short form of dopamine receptor D2 (DRD2S) is efficiently transported to the primary cilia, while a long form of dopamine receptor D2 (DRD2L) is rarely transported to the primary cilia. Using an anti-Prlhr antibody, we found that Prlhr localized to the cilia on the surface of the third ventricle in the vicinity of the hypothalamic periventricular nucleus. We generated the Npy2r-Cre transgenic mouse line in which Cre-recombinase is expressed under the control of the promoter of Npy2r encoding a ciliary GPCR. By mating Npy2r-Cre mice with Ift80 flox mice, we generated Ift80 conditional knockout (CKO) mice in which Npy2r-positive cilia were diminished in number. We found that Ift80 CKO mice exhibited a body weight increase. Our results suggest that Npy2r-positive cilia are important for body weight control.

  6. The impact of Mexico's CRE regulation on Pemex marketing

    International Nuclear Information System (INIS)

    Martinez, A.

    1997-01-01

    The past, present and future of the natural gas industry in Mexico was reviewed. As far as the past is concerned, Pemex-Gas was a state monopoly, not subject to an independent regulatory authority. It was primarily concerned with providing natural gas to domestic consumers, it engaged in minimal marketing activities, and it was highly centralized. In the country as a whole, there was a notable indifference to regulation, and an almost total absence of a regulatory culture. Natural gas was seen as a minor byproduct of petroleum, not as an engine of economic growth. Reforms introduced in May 1995 attempt to institute revolutionary changes by creating a federal regulatory commission, (Comision Reguladora de Energia, CRE for short), and strongly encouraging private sector involvement in the storage, transmission and distribution of natural gas, while reserving exclusive jurisdiction for exploration and production to the State. Provisions of the new natural gas legislation were explained, including the impact on transportation, distribution and retail sales by the State Gas company, Pemex-Gas, and its assigned leading role in bringing about the legislated changes. A fully functioning open access system is expected to be in place by November 1997

  7. Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, Claudia; Dray, Eloise; Groesser, Torsten; San Filippo,Joseph; Shi, Idina; Collins, David W.; Tsai, Miaw-Sheue; Williams,Gareth; Rydberg, Bjorn; Sung, Patrick; Schild, David

    2007-04-11

    Homologous recombination (HR) repairs chromosome damage and is indispensable for tumor suppression in humans. RAD51 mediates the DNA strand pairing step in HR. RAD51AP1 (RAD51 Associated Protein 1) is a RAD51-interacting protein whose function has remained elusive. Knockdown of RAD51AP1 in human cells by RNA interference engenders sensitivity to different types of genotoxic stress. Moreover, RAD51AP1-depleted cells are impaired for the recombinational repair of a DNA double-strand break and exhibit chromatid breaks both spontaneously and upon DNA damaging treatment. Purified RAD51AP1 binds dsDNA and RAD51, and it greatly stimulates the RAD51-mediated D-loop reaction. Biochemical and cytological results show that RAD51AP1 functions at a step subsequent to the assembly of the RAD51-ssDNA nucleoprotein filament. Our findings provide the first evidence that RAD51AP1 helps maintain genomic integrity via RAD51 recombinase enhancement.

  8. A novel system for simultaneous or sequential integration of multiple gene-loading vectors into a defined site of a human artificial chromosome.

    Science.gov (United States)

    Suzuki, Teruhiko; Kazuki, Yasuhiro; Oshimura, Mitsuo; Hara, Takahiko

    2014-01-01

    Human artificial chromosomes (HACs) are gene-delivery vectors suitable for introducing large DNA fragments into mammalian cells. Although a HAC theoretically incorporates multiple gene expression cassettes of unlimited DNA size, its application has been limited because the conventional gene-loading system accepts only one gene-loading vector (GLV) into a HAC. We report a novel method for the simultaneous or sequential integration of multiple GLVs into a HAC vector (designated as the SIM system) via combined usage of Cre, FLP, Bxb1, and φC31 recombinase/integrase. As a proof of principle, we first attempted simultaneous integration of three GLVs encoding EGFP, Venus, and TdTomato into a gene-loading site of a HAC in CHO cells. These cells successfully expressed all three fluorescent proteins. Furthermore, microcell-mediated transfer of HACs enabled the expression of those fluorescent proteins in recipient cells. We next demonstrated that GLVs could be introduced into a HAC one-by-one via reciprocal usage of recombinase/integrase. Lastly, we introduced a fourth GLV into a HAC after simultaneous integration of three GLVs by FLP-mediated DNA recombination. The SIM system expands the applicability of HAC vectors and is useful for various biomedical studies, including cell reprogramming.

  9. A novel system for simultaneous or sequential integration of multiple gene-loading vectors into a defined site of a human artificial chromosome.

    Directory of Open Access Journals (Sweden)

    Teruhiko Suzuki

    Full Text Available Human artificial chromosomes (HACs are gene-delivery vectors suitable for introducing large DNA fragments into mammalian cells. Although a HAC theoretically incorporates multiple gene expression cassettes of unlimited DNA size, its application has been limited because the conventional gene-loading system accepts only one gene-loading vector (GLV into a HAC. We report a novel method for the simultaneous or sequential integration of multiple GLVs into a HAC vector (designated as the SIM system via combined usage of Cre, FLP, Bxb1, and φC31 recombinase/integrase. As a proof of principle, we first attempted simultaneous integration of three GLVs encoding EGFP, Venus, and TdTomato into a gene-loading site of a HAC in CHO cells. These cells successfully expressed all three fluorescent proteins. Furthermore, microcell-mediated transfer of HACs enabled the expression of those fluorescent proteins in recipient cells. We next demonstrated that GLVs could be introduced into a HAC one-by-one via reciprocal usage of recombinase/integrase. Lastly, we introduced a fourth GLV into a HAC after simultaneous integration of three GLVs by FLP-mediated DNA recombination. The SIM system expands the applicability of HAC vectors and is useful for various biomedical studies, including cell reprogramming.

  10. K-3 vitamininin sıçan glioma (C6) ve insan glioblastomamultiforme hücre çoğalmasına invitro etkileri

    OpenAIRE

    Öztopçu, Pınar; Kabadere, Selda; Uyar, Ruhi

    2005-01-01

    Amaç: Glioblastoma multiforme beyin dokusu içerisine hızla yayılan ve onu yıkıma ugratan, sinir sisteminde görülme sıklıgı yüksek oldukça tehlikeli bir tümör çesididir. K-3 vitamininin çesitli kanser hücre dizileri üzerinde hücre çogalmasını baskılayıcı etkisi oldugu bildirilmektedir. Çalısmamızda K-3 vitamininin, sıçan glioma (C6) ve insan glioblastoma multiforme hücrelerinin çogalması üzerindeki baskılayıcı etkilerini karsılastırarak belirlemeyi amaçladık. Yöntem: K-3 vitamin...

  11. Duplex recombinase polymerase amplification assays incorporating competitive internal controls for bacterial meningitis detection.

    Science.gov (United States)

    Higgins, Owen; Clancy, Eoin; Forrest, Matthew S; Piepenburg, Olaf; Cormican, Martin; Boo, Teck Wee; O'Sullivan, Nicola; McGuinness, Claire; Cafferty, Deirdre; Cunney, Robert; Smith, Terry J

    2018-04-01

    Recombinase polymerase amplification (RPA) is an isothermal nucleic acid amplification technology that provides rapid and robust infectious disease pathogen detection, ideal for point-of-care (POC) diagnostics in disease-prevalent low-resource countries. We have developed and evaluated three duplex RPA assays incorporating competitive internal controls for the detection of leading bacterial meningitis pathogens. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae singleplex RPA assays were initially developed and evaluated, demonstrating 100% specificity with limits of detection of 4.1, 8.5 and 3.9 genome copies per reaction, respectively. Each assay was further developed into internally controlled duplex RPA assays via the incorporation of internal amplification control templates. Clinical performance of each internally controlled duplex RPA assay was evaluated by testing 64 archived PCR-positive clinical samples. Compared to real-time PCR, all duplex RPA assays demonstrated 100% diagnostic specificity, with diagnostic sensitivities of 100%, 86.3% and 100% for the S. pneumoniae, N. meningitidis and H. influenzae assays, respectively. This study details the first report of internally controlled duplex RPA assays for the detection of bacterial meningitis pathogens: S. pneumoniae, N. meningitidis and H. influenzae. We have successfully demonstrated the clinical diagnostic utility of each duplex RPA assay, introducing effective diagnostic technology for POC bacterial meningitis identification in disease-prevalent developing countries. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. A recombinase polymerase amplification assay for rapid detection of Crimean-Congo Haemorrhagic fever Virus infection.

    Directory of Open Access Journals (Sweden)

    Laura C Bonney

    2017-10-01

    Full Text Available Crimean-Congo Haemorrhagic fever Virus (CCHFV is a rapidly emerging vector-borne pathogen and the cause of a virulent haemorrhagic fever affecting large parts of Europe, Africa, the Middle East and Asia.An isothermal recombinase polymerase amplification (RPA assay was successfully developed for molecular detection of CCHFV. The assay showed rapid (under 10 minutes detection of viral extracts/synthetic virus RNA of all 7 S-segment clades of CCHFV, with high target specificity. The assay was shown to tolerate the presence of inhibitors in crude preparations of mock field samples, indicating that this assay may be suitable for use in the field with minimal sample preparation. The CCHFV RPA was successfully used to screen and detect CCHFV positives from a panel of clinical samples from Tajikistan.The assay is a rapid, isothermal, simple-to-perform molecular diagnostic, which can be performed on a light, portable real-time detection device. It is ideally placed therefore for use as a field-diagnostic or in-low resource laboratories, for monitoring of CCHF outbreaks at the point-of-need, such as in remote rural regions in affected countries.

  13. Isothermal Recombinase Polymerase amplification (RPA) of Schistosoma haematobium DNA and oligochromatographic lateral flow detection.

    Science.gov (United States)

    Rosser, A; Rollinson, D; Forrest, M; Webster, B L

    2015-09-04

    Accurate diagnosis of urogenital schistosomiasis is vital for surveillance/control programs. Amplification of schistosome DNA in urine by PCR is sensitive and specific but requires infrastructure, financial resources and skilled personnel, often not available in endemic areas. Recombinase Polymerase Amplification (RPA) is an isothermal DNA amplification/detection technology that is simple, rapid, portable and needs few resources. Here a Schistosoma haematobium RPA assay was developed and adapted so that DNA amplicons could be detected using oligochromatographic Lateral Flow (LF) strips. The assay successfully amplified S. haematobium DNA at 30-45 °C in 10 mins and was sensitive to a lower limit of 100 fg of DNA. The assay was also successful with the addition of crude urine, up to 5% of the total reaction volume. Cross amplification occurred with other schistosome species but not with other common urine microorganisms. The LF-RPA assay developed here can amplify and detect low levels of S. haematobium DNA. Reactions are rapid, require low temperatures and positive reactions are interpreted using lateral flow strips, reducing the need for infrastructure and resources. This together with an ability to withstand inhibitors within urine makes RPA a promising technology for further development as a molecular diagnostic tool for urogenital schistosomiasis.

  14. Conditional Expression of Wnt4 during Chondrogenesis Leads to Dwarfism in Mice

    Science.gov (United States)

    Lee, Hu-Hui; Behringer, Richard R.

    2007-01-01

    Wnts are expressed in the forming long bones, suggesting roles in skeletogenesis. To examine the action of Wnts in skeleton formation, we developed a genetic system to conditionally express Wnt4 in chondrogenic tissues of the mouse. A mouse Wnt4 cDNA was introduced into the ubiquitously expressed Rosa26 (R26) locus by gene targeting in embryonic stem (ES) cells. The expression of Wnt4 from the R26 locus was blocked by a neomycin selection cassette flanked by loxP sites (floxneo) that was positioned between the Rosa26 promoter and the Wnt4 cDNA, creating the allele designated R26floxneoWnt4. Wnt4 expression was activated during chondrogenesis using Col2a1-Cre transgenic mice that express Cre recombinase in differentiating chondrocytes. R26floxneoWnt4; Col2a1-Cre double heterozygous mice exhibited a growth deficiency, beginning approximately 7 to 10 days after birth, that resulted in dwarfism. In addition, they also had craniofacial abnormalities, and delayed ossification of the lumbar vertebrae and pelvic bones. Histological analysis revealed a disruption in the organization of the growth plates and a delay in the onset of the primary and secondary ossification centers. Molecular studies showed that Wnt4 overexpression caused decreased proliferation and altered maturation of chondrocytes. In addition, R26floxneoWnt4; Col2a1-Cre mice had decreased expression of vascular endothelial growth factor (VEGF). These studies demonstrate that Wnt4 overexpression leads to dwarfism in mice. The data indicate that Wnt4 levels must be regulated in chondrocytes for normal growth plate development and skeletogenesis. Decreased VEGF expression suggests that defects in vascularization may contribute to the dwarf phenotype. PMID:17505543

  15. Conditional expression of Wnt4 during chondrogenesis leads to dwarfism in mice.

    Directory of Open Access Journals (Sweden)

    Hu-Hui Lee

    Full Text Available Wnts are expressed in the forming long bones, suggesting roles in skeletogenesis. To examine the action of Wnts in skeleton formation, we developed a genetic system to conditionally express Wnt4 in chondrogenic tissues of the mouse. A mouse Wnt4 cDNA was introduced into the ubiquitously expressed Rosa26 (R26 locus by gene targeting in embryonic stem (ES cells. The expression of Wnt4 from the R26 locus was blocked by a neomycin selection cassette flanked by loxP sites (floxneo that was positioned between the Rosa26 promoter and the Wnt4 cDNA, creating the allele designated R26(floxneoWnt4. Wnt4 expression was activated during chondrogenesis using Col2a1-Cre transgenic mice that express Cre recombinase in differentiating chondrocytes. R26(floxneoWnt4; Col2a1-Cre double heterozygous mice exhibited a growth deficiency, beginning approximately 7 to 10 days after birth, that resulted in dwarfism. In addition, they also had craniofacial abnormalities, and delayed ossification of the lumbar vertebrae and pelvic bones. Histological analysis revealed a disruption in the organization of the growth plates and a delay in the onset of the primary and secondary ossification centers. Molecular studies showed that Wnt4 overexpression caused decreased proliferation and altered maturation of chondrocytes. In addition, R26(floxneoWnt4; Col2a1-Cre mice had decreased expression of vascular endothelial growth factor (VEGF. These studies demonstrate that Wnt4 overexpression leads to dwarfism in mice. The data indicate that Wnt4 levels must be regulated in chondrocytes for normal growth plate development and skeletogenesis. Decreased VEGF expression suggests that defects in vascularization may contribute to the dwarf phenotype.

  16. New Clox Systems for rapid and efficient gene disruption in Candida albicans.

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    Shahida Shahana

    Full Text Available Precise genome modification is essential for the molecular dissection of Candida albicans, and is yielding invaluable information about the roles of specific gene functions in this major fungal pathogen of humans. C. albicans is naturally diploid, unable to undergo meiosis, and utilizes a non-canonical genetic code. Hence, specialized tools have had to be developed for gene disruption in C. albicans that permit the deletion of both target alleles, and in some cases, the recycling of the Candida-specific selectable markers. Previously, we developed a tool based on the Cre recombinase, which recycles markers in C. albicans with 90-100% efficiency via site-specific recombination between loxP sites. Ironically, the utility of this system was hampered by the extreme efficiency of Cre, which prevented the construction in Escherichia coli of stable disruption cassettes carrying a methionine-regulatable CaMET3p-cre gene flanked by loxP sites. Therefore, we have significantly enhanced this system by engineering new Clox cassettes that carry a synthetic, intron-containing cre gene. The Clox kit facilitates efficient transformation and marker recycling, thereby simplifying and accelerating the process of gene disruption in C. albicans. Indeed, homozygous mutants can be generated and their markers resolved within two weeks. The Clox kit facilitates strategies involving single marker recycling or multi-marker gene disruption. Furthermore, it includes the dominant NAT1 marker, as well as URA3, HIS1 and ARG4 cassettes, thereby permitting the manipulation of clinical isolates as well as genetically marked strains of C. albicans. The accelerated gene disruption strategies afforded by this new Clox system are likely to have a profound impact on the speed with which C. albicans pathobiology can be dissected.

  17. Ultraviolet B (UVB) induction of the c-fos promoter is mediated by phospho-cAMP response element binding protein (CREB) binding to CRE and c-fos activator protein 1 site (FAP1) cis elements.

    Science.gov (United States)

    Gonzales, Melissa; Bowden, G Tim

    2002-06-26

    The ultraviolet B (UVB) portion (280-320 nm) of the ultraviolet spectrum has been shown to contribute to the development of non-melanoma skin cancer in humans. Research in the human keratinocyte cell line, HaCaT, revealed that UVB irradiation caused the upregulation of the transcription factor activator protein-1 (AP-1). The AP-1 complex formed in UVB-irradiated HaCaT cells is specifically composed of c-fos and Jun D. c-Fos expression was induced in a manner that correlated with the UVB-induced activation of AP-1. To investigate how c-fos expression is regulated by UVB irradiation, the role of each of four cis elements within the c-fos promoter was evaluated. Clustered point mutations at the sis inducible element (SIE), serum response element (SRE), c-fos AP-1 site (FAP1), or cyclic AMP response elements (CRE) significantly inhibited UVB induction of the c-fos promoter. This indicated that all four cis elements are required for maximum promoter activity. The CRE and FAP1 elements were the two most active cis elements that mediate the UVB transactivation of c-fos. Homodimers of phosphorylated cAMP response element binding protein (CREB) were induced by UVB irradiation to bind to each of these elements. Therefore, CREB may function as an important regulatory protein in the UVB-induced expression of c-fos.

  18. Factors influencing Recombinase polymerase amplification (RPA) assay outcomes at point of care.

    Science.gov (United States)

    Lillis, Lorraine; Siverson, Joshua; Lee, Arthur; Cantera, Jason; Parker, Mathew; Piepenburg, Olaf; Lehman, Dara A; Boyle, David S

    2016-04-01

    Recombinase Polymerase Amplification (RPA) can be used to detect pathogen-specific DNA or RNA in under 20 min without the need for complex instrumentation. These properties enable its potential use in resource limited settings. However, there are concerns that deviations from the manufacturer's protocol and/or storage conditions could influence its performance in low resource settings. RPA amplification relies upon viscous crowding agents for optimal nucleic acid amplification, and thus an interval mixing step after 3-6 min of incubation is recommended to distribute amplicons and improve performance. In this study we used a HIV-1 RPA assay to evaluate the effects of this mixing step on assay performance. A lack of mixing led to a longer time to amplification and inferior detection signal, compromising the sensitivity of the assay. However lowering the assay volume from 50 μL to 5 μL showed similar sensitivity with or without mixing. We present the first peer-reviewed study that assesses long term stability of RPA reagents without a cold chain. Reagents stored at -20 °C, and 25 °C for up to 12 weeks were able to detect 10 HIV-1 DNA copies. Reagents stored at 45 °C for up to 3 weeks were able to detect 10 HIV-1 DNA copies, with reduced sensitivity only after >3 weeks at 45 °C. Together our results show that reducing reaction volumes bypassed the need for the mixing step and that RPA reagents were stable even when stored for 3 weeks at very high temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange*

    Science.gov (United States)

    Borgogno, María V.; Monti, Mariela R.; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E.; Pezza, Roberto J.

    2016-01-01

    Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3′ end of the initiating DNA strand have a small effect, whereas most mismatches near the 5′ end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. PMID:26709229

  20. Efficient generation of long-distance conditional alleles using recombineering and a dual selection strategy in replicate plates

    Directory of Open Access Journals (Sweden)

    Liang Hong-Erh

    2009-07-01

    Full Text Available Abstract Background Conditional knockout mice are a useful tool to study the function of gene products in a tissue-specific or inducible manner. Classical approaches to generate targeting vectors for conditional alleles are often limited by the availability of suitable restriction sites. Furthermore, plasmid-based targeting vectors can only cover a few kB of DNA which precludes the generation of targeting vectors where the two loxP sites are placed far apart. These limitations have been overcome in the recent past by using homologous recombination of bacterial artificial chromosomes (BACs in Escherichia coli to produce large targeting vector containing two different loxP-flanked selection cassettes so that a single targeting event is sufficient to introduce loxP-sites a great distances into the mouse genome. However, the final targeted allele should be free of selection cassettes and screening for correct removal of selection cassettes can be a laborious task. Therefore, we developed a new strategy to rapidly identify ES cells containing the desired allele. Results Using BAC recombineering we generated a single targeting vector which contained two different selection cassettes that were flanked by loxP-loxP sites or by FRT-FRT/loxP sites so that they could be deleted sequentially by Cre- and FLPe-recombinases, respectively. Transfected ES cells were first selected in the presence of both antibiotics in vitro before correctly targeted clones were identified by Southern blot. After transfection of a Cre recombinase expression plasmid ES cell clones were selected on replicate plates to identify those clones which maintained the FRT-FRT/loxP flanked cassette and lost the loxP-loxP flanked cassette. Using this strategy facilitated the identification of ES cell clones containing the desired allele before blastocyst injection. Conclusion The strategy of ES cell cultures in replicate plates proved to be very efficient in identifying ES cells that had

  1. Rapid detection of Mycobacterium tuberculosis by recombinase polymerase amplification.

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    David S Boyle

    Full Text Available Improved access to effective tests for diagnosing tuberculosis (TB has been designated a public health priority by the World Health Organisation. In high burden TB countries nucleic acid based TB tests have been restricted to centralised laboratories and specialised research settings. Requirements such as a constant electrical supply, air conditioning and skilled, computer literate operators prevent implementation of such tests in many settings. Isothermal DNA amplification technologies permit the use of simpler, less energy intensive detection platforms more suited to low resource settings that allow the accurate diagnosis of a disease within a short timeframe. Recombinase Polymerase Amplification (RPA is a rapid, low temperature isothermal DNA amplification reaction. We report here RPA-based detection of Mycobacterium tuberculosis complex (MTC DNA in <20 minutes at 39 °C. Assays for two MTC specific targets were investigated, IS6110 and IS1081. When testing purified MTC genomic DNA, limits of detection of 6.25 fg (IS6110 and 20 fg (IS1081were consistently achieved. When testing a convenience sample of pulmonary specimens from suspected TB patients, RPA demonstrated superior accuracy to indirect fluorescence microscopy. Compared to culture, sensitivities for the IS1081 RPA and microscopy were 91.4% (95%CI: 85, 97.9 and 86.1% (95%CI: 78.1, 94.1 respectively (n = 71. Specificities were 100% and 88.6% (95% CI: 80.8, 96.1 respectively. For the IS6110 RPA and microscopy sensitivities of 87.5% (95%CI: 81.7, 93.2 and 70.8% (95%CI: 62.9, 78.7 were obtained (n = 90. Specificities were 95.4 (95% CI: 92.3,98.1 and 88% (95% CI: 83.6, 92.4 respectively. The superior specificity of RPA for detecting tuberculosis was due to the reduced ability of fluorescence microscopy to distinguish Mtb complex from other acid fast bacteria. The rapid nature of the RPA assay and its low energy requirement compared to other amplification technologies suggest RPA-based TB

  2. Regulation of Recombination between gtfB/gtfC Genes in Streptococcus mutans by Recombinase A

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    Satoko Inagaki

    2013-01-01

    Full Text Available Streptococcus mutans produces 3 types of glucosyltransferases (GTFs, whose cooperative action is essential for cellular adhesion. The recombinase A (RecA protein is required for homologous recombination. In our previous study, we isolated several strains with a smooth colony morphology and low GTF activity, characteristics speculated to be derived from the GTF fusions. The purpose of the present study was to investigate the mechanism of those fusions. S. mutans strain MT8148 was grown in the presence of recombinant RecA (rRecA protein, after which smooth colonies were isolated. The biological functions and sequences of the gtfB and gtfC genes of this as well as other clinical strains were determined. The sucrose-dependent adherence rates of those strains were reduced as compared to that of MT8148. Determination of the sequences of the gtfB and gtfC genes showed that an approximately 3500 bp region was deleted from the area between them. Furthermore, expression of the recA gene was elevated in those strains as compared to MT8148. These results suggest that RecA has an important role in fusions of gtfB and gtfC genes, leading to alteration of colony morphology and reduction in sucrose-dependent adhesion.

  3. New Fpg probe chemistry for direct detection of recombinase polymerase amplification on lateral flow strips.

    Science.gov (United States)

    Powell, Michael L; Bowler, Frank R; Martinez, Aurore J; Greenwood, Catherine J; Armes, Niall; Piepenburg, Olaf

    2018-02-15

    Rapid, cost-effective and sensitive detection of nucleic acids has the ability to improve upon current practices employed for pathogen detection in diagnosis of infectious disease and food testing. Furthermore, if assay complexity can be reduced, nucleic acid amplification tests could be deployed in resource-limited and home use scenarios. In this study, we developed a novel Fpg (Formamidopyrimidine DNA glycosylase) probe chemistry, which allows lateral flow detection of amplification in undiluted recombinase polymerase amplification (RPA) reactions. The prototype nucleic acid lateral flow chemistry was applied to a human genomic target (rs1207445), Campylobacter jejuni 16S rDNA and two genetic markers of the important food pathogen E. coli O157:H7. All four assays have an analytical sensitivity between 10 and 100 copies DNA per amplification. Furthermore, the assay is performed with fewer hands-on steps than using the current RPA Nfo lateral flow method as dilution of amplicon is not required for lateral flow analysis. Due to the simplicity of the workflow, we believe that the lateral flow chemistry for direct detection could be readily adapted to a cost-effective single-use consumable, ideal for use in non-laboratory settings. Copyright © 2017. Published by Elsevier Inc.

  4. Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange.

    Science.gov (United States)

    Borgogno, María V; Monti, Mariela R; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E; Pezza, Roberto J

    2016-03-04

    Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3' end of the initiating DNA strand have a small effect, whereas most mismatches near the 5' end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Effects of rolipram, a phosphodiesterase 4 inhibitor, in combination with imipramine on depressive behavior, CRE-binding activity and BDNF level in learned helplessness rats.

    Science.gov (United States)

    Itoh, Tetsuji; Tokumura, Miwa; Abe, Kohji

    2004-09-13

    The brain cAMP regulating system and its downstream elements play a pivotal role in the therapeutic effects of antidepressants. We previously reported the increase in activities of phosphodiesterase 4, a major phosphodiesterase isozyme hydrolyzing cAMP, in the frontal cortex and hippocampus of learned helplessness rats, an animal model for depression. The present study was undertaken to examine the combination of effects of rolipram, a phosphodiesterase 4 inhibitor, with imipramine, a typical tricyclic antidepressant, on depressive behavior in learned helplessness rats. Concurrently, cAMP-response element (CRE)-binding activity and brain-derived neurotrophic factor (BDNF) levels related to the therapeutic effects of antidepressants were determined. Repeated administration of imipramine (1.25-10 mg/kg, i.p.) or rolipram (1.25 mg/kg, i.p.) reduced the number of escape failures in learned helplessness rats. Imipramine could not completely ameliorate the escape behavior to a level similar to that of non-stressed rats even at 10 mg/kg. However, repeated coadministration of rolipram with imipramine (1.25 and 2.5 mg/kg, respectively) almost completely eliminated the escape failures in learned helplessness rats. The reduction of CRE-binding activities and BDNF levels in the frontal cortex or hippocampus in learned helplessness rats were ameliorated by treatment with imipramine or rolipram alone. CRE-binding activities and/or BDNF levels of the frontal cortex and hippocampus were significantly increased by treatment with a combination of rolipram and imipramine compared to those in imipramine-treated rats. These results indicated that coadministration of phosphodiesterase type 4 inhibitors with antidepressants may be more effective for depression therapy and suggest that elevation of the cAMP signal transduction pathway is involved in the antidepressive effects.

  6. Relationship between neurometabolite derangement and neurocognitive dysfunction in systemic lupus erythematosus.

    Science.gov (United States)

    Brooks, W M; Jung, R E; Ford, C C; Greinel, E J; Sibbitt, W L

    1999-01-01

    To determine the relationship between neurochemical markers of brain injury and brain dysfunction associated with systemic lupus erythematosus (SLE). Patients with SLE (n = 12) were studied using magnetic resonance spectroscopic imaging at 1.5 Tesla to determine neurochemistry and a neurocognitive testing battery to determine brain dysfunction. N-acetylaspartate (NAA), creatine (Cre), and choline (Cho) concentrations were measured in white (WM) and gray (GM) matter and expressed as the ratios NAA/Cho, NAA/Cre, and Cho/Cre. Neurocognitive testing results were expressed as a composite z score. Disease activity was quantified by SLE Disease Activity Index (SLEDAI) and disease injury by Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology Damage Index. Neurochemical measures of brain injury were correlated with neurocognitive testing z scores: NAA/Cho in WM (r = 0.77, p = 0.003) and GM (r = 0.67, p = 0.017); WM Cho/Cre also correlated with total z score (r = -0.74, p = 0.006). Neurometabolite ratios and SLICC were correlated: GM NAA/Cho (r = -0.70, p = 0.011 ) and NAA/Cre (r = -0.71, p = 0.01) and WM Cho/Cre (r = 0.66, p = 0.02). Correlations between neurometabolite ratios and SLEDAI did not reach significance. Brain function is closely correlated with brain injury assessed noninvasively by proton magnetic resonance spectroscopy. This important finding further supports the use of magnetic resonance spectroscopy to evaluate brain injury in SLE.

  7. Efficient Recombinase-Mediated Cassette Exchange in hPSCs to Study the Hepatocyte Lineage Reveals AAVS1 Locus-Mediated Transgene Inhibition

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    Laura Ordovás

    2015-11-01

    Full Text Available Tools for rapid and efficient transgenesis in “safe harbor” loci in an isogenic context remain important to exploit the possibilities of human pluripotent stem cells (hPSCs. We created hPSC master cell lines suitable for FLPe recombinase-mediated cassette exchange (RMCE in the AAVS1 locus that allow generation of transgenic lines within 15 days with 100% efficiency and without random integrations. Using RMCE, we successfully incorporated several transgenes useful for lineage identification, cell toxicity studies, and gene overexpression to study the hepatocyte lineage. However, we observed unexpected and variable transgene expression inhibition in vitro, due to DNA methylation and other unknown mechanisms, both in undifferentiated hESC and differentiating hepatocytes. Therefore, the AAVS1 locus cannot be considered a universally safe harbor locus for reliable transgene expression in vitro, and using it for transgenesis in hPSC will require careful assessment of the function of individual transgenes.

  8. JMJD3 Is Crucial for the Female AVPV RIP-Cre Neuron-Controlled Kisspeptin-Estrogen Feedback Loop and Reproductive Function.

    Science.gov (United States)

    Song, Anying; Jiang, Shujun; Wang, Qinghua; Zou, Jianghuan; Lin, Zhaoyu; Gao, Xiang

    2017-06-01

    The hypothalamic-pituitary-gonadal axis controls development, reproduction, and metabolism. Although most studies have focused on the hierarchy from the brain to the gonad, many questions remain unresolved concerning the feedback from the gonad to the central nervous system, especially regarding the potential epigenetic modifications in hypothalamic neurons. In the present report, we generated genetically modified mice lacking histone H3 lysine 27 (H3K27) demethylase Jumonji domain-containing 3 (JMJD3) in hypothalamic rat-insulin-promoter-expressing neurons (RIP-Cre neurons). The female mutant mice displayed late-onset obesity owing to reduced locomotor activity and decreased energy expenditure. JMJD3 deficiency in RIP-Cre neurons also results in delayed pubertal onset, an irregular estrous cycle, impaired fertility, and accelerated ovarian failure in female mice owing to the dysregulation of the hypothalamic-ovarian axis. We found that JMJD3 directly regulates Kiss1 gene expression by binding to the Kiss1 promoter and triggering H3K27me3 demethylation in the anteroventral periventricular (AVPV) nucleus. Further study confirmed that the aberrations arose from impaired kisspeptin signaling in the hypothalamic AVPV nucleus and subsequent estrogen deficiency. Estrogen replacement therapy can reverse obesity in mutant mice. Moreover, we demonstrated that Jmjd3 is an estrogen target gene in the hypothalamus. These results provide direct genetic and molecular evidence that JMJD3 is a key mediator for the kisspeptin-estrogen feedback loop. Copyright © 2017 Endocrine Society.

  9. Perturbations of NAD+ salvage systems impact mitochondrial function and energy homeostasis in mouse myoblasts and intact skeletal muscle

    DEFF Research Database (Denmark)

    Andersen, Marianne Agerholm; Dall, Morten; Jensen, Benjamin Anderschou Holbech

    2018-01-01

    Nicotinamide adenine dinucleotide (NAD+) can be synthesized by nicotinamide phosphoribosyltransferase (NAMPT). We aimed to determine the role of NAMPT for maintaining NAD+ levels, mitochondrial function, and metabolic homeostasis in skeletal muscle cells. We generated stable Nampt knockdown (sh......Nampt KD) C2C12 cells using a shRNA lentiviral approach. Moreover, we applied gene electrotransfer to express cre recombinase in tibialis anterior muscle of floxed Nampt mice. In shNampt KD C2C12 myoblasts, Nampt and NAD+ levels were reduced by 70% and 50%, respectively, and maximal respiratory capacity...... was reduced by 25%. Moreover, anaerobic glycolytic flux increased by 55% and 2-deoxyglucose uptake increased by 25% in shNampt KD cells. Treatment with the NAD+ precursor nicotinamide riboside restored NAD+ levels in shNampt cells and increased maximal respiratory capacity by 18% and 32% in control and sh...

  10. Single-Step Generation of Conditional Knockout Mouse Embryonic Stem Cells

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    Matyas Flemr

    2015-07-01

    Full Text Available Induction of double-strand DNA breaks (DSBs by engineered nucleases, such as CRISPR/Cas9 or transcription activator-like effector nucleases (TALENs, stimulates knockin of exogenous DNA fragments via homologous recombination (HR. However, the knockin efficiencies reported so far have not allowed more complex in vitro genome modifications such as, for instance, simultaneous integration of a DNA fragment at two distinct genomic sites. We developed a reporter system to enrich for cells with engineered nuclease-assisted HR events. Using this system in mouse embryonic stem cells (mESCs, we achieve single-step biallelic and seamless integration of two loxP sites for Cre recombinase-mediated inducible gene knockout, as well as biallelic endogenous gene tagging with high efficiency. Our approach reduces the time and resources required for conditional knockout mESC generation dramatically.

  11. Cre/lox-recombinase-mediated cassette exchange for reversible site-specific genomic targeting of the disease vector, Aedes aegypti

    Science.gov (United States)

    Site-specific genome modification is an important tool for mosquito functional genomics studies that help to uncover gene functions, identify gene regulatory elements, and perform comparative gene expression studies, all of which contribute to a better understanding of mosquito biology and are thus ...

  12. Activation of Six1 Expression in Vertebrate Sensory Neurons.

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    Shigeru Sato

    Full Text Available SIX1 homeodomain protein is one of the essential key regulators of sensory organ development. Six1-deficient mice lack the olfactory epithelium, vomeronasal organs, cochlea, vestibule and vestibuloacoustic ganglion, and also show poor neural differentiation in the distal part of the cranial ganglia. Simultaneous loss of both Six1 and Six4 leads to additional abnormalities such as small trigeminal ganglion and abnormal dorsal root ganglia (DRG. The aim of this study was to understand the molecular mechanism that controls Six1 expression in sensory organs, particularly in the trigeminal ganglion and DRG. To this end, we focused on the sensory ganglia-specific Six1 enhancer (Six1-8 conserved between chick and mouse. In vivo reporter assays using both animals identified an important core region comprising binding consensus sequences for several transcription factors including nuclear hormone receptors, TCF/LEF, SMAD, POU homeodomain and basic-helix-loop-helix proteins. The results provided information on upstream factors and signals potentially relevant to Six1 regulation in sensory neurons. We also report the establishment of a new transgenic mouse line (mSix1-8-NLSCre that expresses Cre recombinase under the control of mouse Six1-8. Cre-mediated recombination was detected specifically in ISL1/2-positive sensory neurons of Six1-positive cranial sensory ganglia and DRG. The unique features of the mSix1-8-NLSCre line are the absence of Cre-mediated recombination in SOX10-positive glial cells and central nervous system and ability to induce recombination in a subset of neurons derived from the olfactory placode/epithelium. This mouse model can be potentially used to advance research on sensory development.

  13. Communication from the CRE relative to the calculation of the charges of the power production public utility for the year 2002; Communication de la CRE relative au calcul des charges du service public de la production d'electricite pour l'annee 2002

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-05-01

    After having analyzed the answers given to the public inquiry about the methods used for the calculation of the saved costs, the French commission of electricity regulation (CRE) indicates in this document the trends it has retained for the calculation of the charges of the power production public utility for 2002: cost overruns due to the obligation of purchase and to the purchase contracts anterior to the law from February 10, 2000; production cost overruns in non-interconnected areas (Corsica and overseas departments). (J.S.)

  14. Ihh and PTH1R signaling in limb mesenchyme is required for proper segmentation and subsequent formation and growth of digit bones.

    Science.gov (United States)

    Amano, Katsuhiko; Densmore, Michael; Fan, Yi; Lanske, Beate

    2016-02-01

    Digit formation is a process, which requires the proper segmentation, formation and growth of phalangeal bones and is precisely regulated by several important factors. One such factor is Ihh, a gene linked to BDA1 and distal symphalangism in humans. In existing mouse models, mutations in Ihh have been shown to cause multiple synostosis in the digits but lead to perinatal lethality. To better study the exact biological and pathological events which occur in these fused digits, we used a more viable Prx1-Cre;Ihh(fl/fl) model in which Cre recombinase is expressed during mesenchymal condensation in the earliest limb buds at E9.5 dpc and found that mutant digits continuously fuse postnatally until phalanges are finally replaced by an unsegmented "one-stick bone". Mutant mice displayed osteocalcin-positive mature osteoblasts, but had reduced proliferation and abnormal osteogenesis. Because of the close interaction between Ihh and PTHrP during endochondral ossification, we also examined the digits of Prx1-Cre;PTH1R(fl/fl) mice, where the receptor for PTHrP was conditionally deleted. Surprisingly, we found PTH1R deletion caused symphalangism, demonstrating another novel function of PTH1R signaling in digit formation. We characterized the symphalangism process whereby initial cartilaginous fusion prevented epiphyseal growth plate formation, resulting in resorption and replacement of the remaining cartilage by bony tissue. Chondrocyte differentiation displayed abnormal directionality in both mutants. Lastly, Prx1-Cre;Ihh(fl/fl);Jansen Tg mice, in which a constitutively active PTH1R allele was introduced into Ihh mutants, were established to address the possible involvement of PTH1R signaling in Ihh mutant digits. These rescue mice failed to show significantly improved phenotype, suggesting that PTH1R signaling in chondrocytes is not sufficient to restore digit formation. Our results demonstrate that Ihh and PTH1R signaling in limb mesenchyme are both essential to regulate

  15. Conditional inactivation of p53 in mouse ovarian surface epithelium does not alter MIS driven Smad2-dominant negative epithelium-lined inclusion cysts or teratomas.

    Directory of Open Access Journals (Sweden)

    Suzanne M Quartuccio

    Full Text Available Epithelial ovarian cancer is the most lethal gynecological malignancy among US women. The etiology of this disease, although poorly understood, may involve the ovarian surface epithelium or the epithelium of the fallopian tube fimbriae as the progenitor cell. Disruptions in the transforming growth factor beta (TGFβ pathway and p53 are frequently found in chemotherapy-resistant serous ovarian tumors. Transgenic mice expressing a dominant negative form of Smad2 (Smad2DN, a downstream transcription factor of the TGFβ signaling pathway, targeted to tissues of the reproductive tract were created on a FVB background. These mice developed epithelium-lined inclusion cysts, a potential precursor lesion to ovarian cancer, which morphologically resembled oviductal epithelium but exhibited protein expression more closely resembling the ovarian surface epithelium. An additional genetic "hit" of p53 deletion was predicted to result in ovarian tumors. Tissue specific deletion of p53 in the ovaries and oviducts alone was attempted through intrabursal or intraoviductal injection of Cre-recombinase expressing adenovirus (AdCreGFP into p53 (flox/flox mice. Ovarian bursal cysts were detected in some mice 6 months after intrabursal injection. No pathological abnormalities were detected in mice with intraoviductal injections, which may be related to decreased infectivity of the oviductal epithelium with adenovirus as compared to the ovarian surface epithelium. Bitransgenic mice, expressing both the Smad2DN transgene and p53 (flox/flox, were then exposed to AdCreGFP in the bursa and oviductal lumen. These mice did not develop any additional phenotypes. Exposure to AdCreGFP is not an effective methodology for conditional deletion of floxed genes in oviductal epithelium and tissue specific promoters should be employed in future mouse models of the disease. In addition, a novel phenotype was observed in mice with high expression of the Smad2DN transgene as validated

  16. A Stabilizing Feedback Between Cloud Radiative Effects and Greenland Surface Melt: Verification From Multi-year Automatic Weather Station Measurements

    Science.gov (United States)

    Zender, C. S.; Wang, W.; van As, D.

    2017-12-01

    Clouds have strong impacts on Greenland's surface melt through the interaction with the dry atmosphere and reflective surfaces. However, their effects are uncertain due to the lack of in situ observations. To better quantify cloud radiative effects (CRE) in Greenland, we analyze and interpret multi-year radiation measurements from 30 automatic weather stations encompassing a broad range of climatological and topographical conditions. During melt season, clouds warm surface over most of Greenland, meaning the longwave greenhouse effect outweighs the shortwave shading effect; on the other hand, the spatial variability of net (longwave and shortwave) CRE is dominated by shortwave CRE and in turn by surface albedo, which controls the potential absorption of solar radiation when clouds are absent. The net warming effect decreases with shortwave CRE from high to low altitudes and from north to south (Fig. 1). The spatial correlation between albedo and net CRE is strong (r=0.93, palbedo determines the net CRE seasonal trend, which decreases from May to July and increases afterwards. On an hourly timescale, we find two distinct radiative states in Greenland (Fig. 2). The clear state is characterized by clear-sky conditions or thin clouds, when albedo and solar zenith angle (SZA) weakly correlates with CRE. The cloudy state is characterized by opaque clouds, when the combination of albedo and SZA strongly correlates with CRE (r=0.85, palbedo and solar zenith angle, explains the majority of the CRE variation in spatial distribution, seasonal trend in the ablation zone, and in hourly variability in the cloudy radiative state. Clouds warm the brighter and colder surfaces of Greenland, enhance snow melt, and tend to lower the albedo. Clouds cool the darker and warmer surfaces, inhibiting snow melt, which increases albedo, and thus stabilizes surface melt. This stabilizing mechanism may also occur over sea ice, helping to forestall surface melt as the Arctic becomes dimmer.

  17. Recombinase polymerase amplification (RPA) of CaMV-35S promoter and nos terminator for rapid detection of genetically modified crops.

    Science.gov (United States)

    Xu, Chao; Li, Liang; Jin, Wujun; Wan, Yusong

    2014-10-10

    Recombinase polymerase amplification (RPA) is a novel isothermal DNA amplification and detection technology that enables the amplification of DNA within 30 min at a constant temperature of 37-42 °C by simulating in vivo DNA recombination. In this study, based on the regulatory sequence of the cauliflower mosaic virus 35S (CaMV-35S) promoter and the Agrobacterium tumefaciens nopaline synthase gene (nos) terminator, which are widely incorporated in genetically modified (GM) crops, we designed two sets of RPA primers and established a real-time RPA detection method for GM crop screening and detection. This method could reliably detect as few as 100 copies of the target molecule in a sample within 15-25 min. Furthermore, the real-time RPA detection method was successfully used to amplify and detect DNA from samples of four major GM crops (maize, rice, cotton, and soybean). With this novel amplification method, the test time was significantly shortened and the reaction process was simplified; thus, this method represents an effective approach to the rapid detection of GM crops.

  18. Recombinase Polymerase Amplification (RPA of CaMV-35S Promoter and nos Terminator for Rapid Detection of Genetically Modified Crops

    Directory of Open Access Journals (Sweden)

    Chao Xu

    2014-10-01

    Full Text Available Recombinase polymerase amplification (RPA is a novel isothermal DNA amplification and detection technology that enables the amplification of DNA within 30 min at a constant temperature of 37–42 °C by simulating in vivo DNA recombination. In this study, based on the regulatory sequence of the cauliflower mosaic virus 35S (CaMV-35S promoter and the Agrobacterium tumefaciens nopaline synthase gene (nos terminator, which are widely incorporated in genetically modified (GM crops, we designed two sets of RPA primers and established a real-time RPA detection method for GM crop screening and detection. This method could reliably detect as few as 100 copies of the target molecule in a sample within 15–25 min. Furthermore, the real-time RPA detection method was successfully used to amplify and detect DNA from samples of four major GM crops (maize, rice, cotton, and soybean. With this novel amplification method, the test time was significantly shortened and the reaction process was simplified; thus, this method represents an effective approach to the rapid detection of GM crops.

  19. Instant, Visual, and Instrument-Free Method for On-Site Screening of GTS 40-3-2 Soybean Based on Body-Heat Triggered Recombinase Polymerase Amplification.

    Science.gov (United States)

    Wang, Rui; Zhang, Fang; Wang, Liu; Qian, Wenjuan; Qian, Cheng; Wu, Jian; Ying, Yibin

    2017-04-18

    On-site monitoring the plantation of genetically modified (GM) crops is of critical importance in agriculture industry throughout the world. In this paper, a simple, visual and instrument-free method for instant on-site detection of GTS 40-3-2 soybean has been developed. It is based on body-heat recombinase polymerase amplification (RPA) and followed with naked-eye detection via fluorescent DNA dye. Combining with extremely simplified sample preparation, the whole detection process can be accomplished within 10 min and the fluorescent results can be photographed by an accompanied smart phone. Results demonstrated a 100% detection rate for screening of practical GTS 40-3-2 soybean samples by 20 volunteers under different ambient temperatures. This method is not only suitable for on-site detection of GM crops but also demonstrates great potential to be applied in other fields.

  20. Site-specific cassette exchange systems in the Aedes aegypti mosquito and the Plutella xylostella moth.

    Directory of Open Access Journals (Sweden)

    Roya Elaine Haghighat-Khah

    Full Text Available Genetically engineered insects are being evaluated as potential tools to decrease the economic and public health burden of mosquitoes and agricultural pest insects. Here we describe a new tool for the reliable and targeted genome manipulation of pest insects for research and field release using recombinase mediated cassette exchange (RMCE mechanisms. We successfully demonstrated the established ΦC31-RMCE method in the yellow fever mosquito, Aedes aegypti, which is the first report of RMCE in mosquitoes. A new variant of this RMCE system, called iRMCE, combines the ΦC31-att integration system and Cre or FLP-mediated excision to remove extraneous sequences introduced as part of the site-specific integration process. Complete iRMCE was achieved in two important insect pests, Aedes aegypti and the diamondback moth, Plutella xylostella, demonstrating the transferability of the system across a wide phylogenetic range of insect pests.

  1. Site-Specific Cassette Exchange Systems in the Aedes aegypti Mosquito and the Plutella xylostella Moth

    Science.gov (United States)

    Haghighat-Khah, Roya Elaine; Scaife, Sarah; Martins, Sara; St John, Oliver; Matzen, Kelly Jean; Morrison, Neil; Alphey, Luke

    2015-01-01

    Genetically engineered insects are being evaluated as potential tools to decrease the economic and public health burden of mosquitoes and agricultural pest insects. Here we describe a new tool for the reliable and targeted genome manipulation of pest insects for research and field release using recombinase mediated cassette exchange (RMCE) mechanisms. We successfully demonstrated the established ΦC31-RMCE method in the yellow fever mosquito, Aedes aegypti, which is the first report of RMCE in mosquitoes. A new variant of this RMCE system, called iRMCE, combines the ΦC31-att integration system and Cre or FLP-mediated excision to remove extraneous sequences introduced as part of the site-specific integration process. Complete iRMCE was achieved in two important insect pests, Aedes aegypti and the diamondback moth, Plutella xylostella, demonstrating the transferability of the system across a wide phylogenetic range of insect pests. PMID:25830287

  2. c-Kit-mediated functional positioning of stem cells to their niches is essential for maintenance and regeneration of adult hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Yuki Kimura

    Full Text Available The mechanism by which hematopoietic stem and progenitor cells (HSPCs through interaction with their niches maintain and reconstitute adult hematopoietic cells is unknown. To functionally and genetically track localization of HSPCs with their niches, we employed novel mutant loxPs, lox66 and lox71 and Cre-recombinase technology to conditionally delete c-Kit in adult mice, while simultaneously enabling GFP expression in the c-Kit-deficient cells. Conditional deletion of c-Kit resulted in hematopoietic failure and splenic atrophy both at steady state and after marrow ablation leading to the demise of the treated adult mice. Within the marrow, the c-Kit-expressing GFP(+ cells were positioned to Kit ligand (KL-expressing niche cells. This c-Kit-mediated cellular adhesion was essential for long-term maintenance and expansion of HSPCs. These results lay the foundation for delivering KL within specific niches to maintain and restore hematopoiesis.

  3. v-src induction of the TIS10/PGS2 prostaglandin synthase gene is mediated by an ATF/CRE transcription response element.

    OpenAIRE

    Xie, W; Fletcher, B S; Andersen, R D; Herschman, H R

    1994-01-01

    We recently reported the cloning of a mitogen-inducible prostaglandin synthase gene, TIS10/PGS2. In addition to growth factors and tumor promoters, the v-src oncogene induces TIS10/PGS2 expression in 3T3 cells. Deletion analysis, using luciferase reporters, identifies a region between -80 and -40 nucleotides 5' of the TIS10/PGS2 transcription start site that mediates pp60v-src induction in 3T3 cells. This region contains the sequence CGTCACGTG, which includes overlapping ATF/CRE (CGTCA) and E...

  4. Restoration of Lepr in β cells of Lepr null mice does not prevent hyperinsulinemia and hyperglycemia

    Directory of Open Access Journals (Sweden)

    Anna M. D'souza

    2017-06-01

    Full Text Available Objective: The adipose-derived hormone leptin plays an important role in regulating body weight and glucose homeostasis. Leptin receptors are expressed in the central nervous system as well as peripheral tissues involved in regulating glucose homeostasis, including insulin-producing β cells of the pancreas. Previous studies assessing the role of leptin receptors in β cells used Cre-loxP to disrupt the leptin receptor gene (Lepr in β cells, but variable results were obtained. Furthermore, recombination of Lepr was observed in the hypothalamus or exocrine pancreas, in addition to the β cells, and Lepr in non-β cells may have compensated for the loss of Lepr in β cells, thus making it difficult to assess the direct effects of Lepr in β cells. To determine the significance of Lepr exclusively in β cells, we chose to selectively restore Lepr in β cells of Lepr null mice (LeprloxTB/loxTB. Materials and methods: We used a mouse model in which endogenous expression of Lepr was disrupted by a loxP-flanked transcription blocker (LeprloxTB/loxTB, but was restored by Cre recombinase knocked into the Ins1 gene, which is specifically expressed in β cells (Ins1Cre. We bred LeprloxTB/loxTB and Ins1Cre mice to generate LeprloxTB/loxTB and LeprloxTB/loxTB Ins1Cre mice, as well as Leprwt/wt and Leprwt/wt Ins1Cre littermate mice. Male and female mice were weighed weekly between 6 and 11 weeks of age and fasting blood glucose was measured during this time. Oral glucose was administered to mice aged 7–12 weeks to assess glucose tolerance and insulin secretion. Relative β and α cell area and islet size were also assessed by immunostaining and analysis of pancreas sections of 12–14 week old mice. Results: Male and female LeprloxTB/loxTB mice, lacking whole-body expression of Lepr, had a phenotype similar to db/db mice characterized by obesity, hyperinsulinemia, glucose intolerance, and impaired glucose stimulated insulin secretion. Despite restoring

  5. Mammary Specific Expression of Cre Recombinase Under the Control of an Endogenous MMTV LTR: A Conditional Knock-Out System

    National Research Council Canada - National Science Library

    Czarneski, Jennifer

    2000-01-01

    .... The hypothesis of the project was to develop a novel breast cancer model using the tissue-specific expression of the Mtv-17 locus, which was previously shown by this lab to only be expressed in the mammary gland...

  6. L-rhamnose induction of Aspergillus nidulans α-L-rhamnosidase genes is glucose repressed via a CreA-independent mechanism acting at the level of inducer uptake.

    Science.gov (United States)

    Tamayo-Ramos, Juan A; Flipphi, Michel; Pardo, Ester; Manzanares, Paloma; Orejas, Margarita

    2012-02-21

    Little is known about the structure and regulation of fungal α-L-rhamnosidase genes despite increasing interest in the biotechnological potential of the enzymes that they encode. Whilst the paradigmatic filamentous fungus Aspergillus nidulans growing on L-rhamnose produces an α-L-rhamnosidase suitable for oenological applications, at least eight genes encoding putative α-L-rhamnosidases have been found in its genome. In the current work we have identified the gene (rhaE) encoding the former activity, and characterization of its expression has revealed a novel regulatory mechanism. A shared pattern of expression has also been observed for a second α-L-rhamnosidase gene, (AN10277/rhaA). Amino acid sequence data for the oenological α-L-rhamnosidase were determined using MALDI-TOF mass spectrometry and correspond to the amino acid sequence deduced from AN7151 (rhaE). The cDNA of rhaE was expressed in Saccharomyces cerevisiae and yielded pNP-rhamnohydrolase activity. Phylogenetic analysis has revealed this eukaryotic α-L-rhamnosidase to be the first such enzyme found to be more closely related to bacterial rhamnosidases than other α-L-rhamnosidases of fungal origin. Northern analyses of diverse A. nidulans strains cultivated under different growth conditions indicate that rhaA and rhaE are induced by L-rhamnose and repressed by D-glucose as well as other carbon sources, some of which are considered to be non-repressive growth substrates. Interestingly, the transcriptional repression is independent of the wide domain carbon catabolite repressor CreA. Gene induction and glucose repression of these rha genes correlate with the uptake, or lack of it, of the inducing carbon source L-rhamnose, suggesting a prominent role for inducer exclusion in repression. The A. nidulans rhaE gene encodes an α-L-rhamnosidase phylogenetically distant to those described in filamentous fungi, and its expression is regulated by a novel CreA-independent mechanism. The identification of

  7. Cell-Type-Specific Circuit Connectivity of Hippocampal CA1 Revealed through Cre-Dependent Rabies Tracing

    Directory of Open Access Journals (Sweden)

    Yanjun Sun

    2014-04-01

    Full Text Available We developed and applied a Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to specific CA1 neuron types in the mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, the entorhinal cortex (EC, the medial septum (MS, and, unexpectedly, the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons, whereas inhibitory neurons receive a great majority of inputs from GABAergic MS neurons. Both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons received much stronger input than SOM+ neurons from CA3, the EC, and the MS. Thus, rabies tracing identifies hippocampal circuit connections and maps how the different input sources to CA1 are distributed with different strengths on each of its constituent cell types.

  8. Recombinase Polymerase Amplification Compared to Real-Time Polymerase Chain Reaction Test for the Detection of Fasciola hepatica in Human Stool

    Science.gov (United States)

    Cabada, Miguel M.; Malaga, Jose L.; Castellanos-Gonzalez, Alejandro; Bagwell, Kelli A.; Naeger, Patrick A.; Rogers, Hayley K.; Maharsi, Safa; Mbaka, Maryann; White, A. Clinton

    2017-01-01

    Fasciola hepatica is the most widely distributed trematode infection in the world. Control efforts may be hindered by the lack of diagnostic capacity especially in remote endemic areas. Polymerase chain reaction (PCR)–based methods offer high sensitivity and specificity but require expensive technology. However, the recombinase polymerase amplification (RPA) is an efficient isothermal method that eliminates the need for a thermal cycler and has a high deployment potential to resource-limited settings. We report on the characterization of RPA and PCR tests to detect Fasciola infection in clinical stool samples with low egg burdens. The sensitivity of the RPA and PCR were 87% and 66%, respectively. Both tests were 100% specific showing no cross-reactivity with trematode, cestode, or nematode parasites. In addition, RPA and PCR were able to detect 47% and 26% of infections not detected by microscopy, respectively. The RPA adapted to a lateral flow platform was more sensitive than gel-based detection of the reaction products. In conclusion, the Fasciola RPA is a highly sensitive and specific test to diagnose chronic infection using stool samples. The Fasciola RPA lateral flow has the potential for deployment to endemic areas after further characterization. PMID:27821691

  9. RoMo: An efficient strategy for functional mosaic analysis via stochastic Cre recombination and gene targeting in the ROSA26 locus.

    Science.gov (United States)

    Movahedi, Kiavash; Wiegmann, Robert; De Vlaminck, Karen; Van Ginderachter, Jo A; Nikolaev, Viacheslav O

    2018-07-01

    Functional mosaic analysis allows for the direct comparison of mutant cells with differentially marked control cells in the same organism. While this offers a powerful approach for elucidating the role of specific genes or signalling pathways in cell populations of interest, genetic strategies for generating functional mosaicism remain challenging. We describe a novel and streamlined approach for functional mosaic analysis, which combines stochastic Cre/lox recombination with gene targeting in the ROSA26 locus. With the RoMo strategy a cell population of interest is randomly split into a cyan fluorescent and red fluorescent subset, of which the latter overexpresses a chosen transgene. To integrate this approach into high-throughput gene targeting initiatives, we developed a procedure that utilizes Gateway cloning for the generation of new targeting vectors. RoMo can be used for gain-of-function experiments or for altering signaling pathways in a mosaic fashion. To demonstrate this, we developed RoMo-dnGs mice, in which Cre-recombined red fluorescent cells co-express a dominant-negative Gs protein. RoMo-dnGs mice allowed us to inhibit G protein-coupled receptor activation in a fraction of cells, which could then be directly compared to differentially marked control cells in the same animal. We demonstrate how RoMo-dnGs mice can be used to obtain mosaicism in the brain and in peripheral organs for various cell types. RoMo offers an efficient new approach for functional mosaic analysis that extends the current toolbox and may reveal important new insights into in vivo gene function. © 2018 Wiley Periodicals, Inc.

  10. Normal Collagen and Bone Production by Gene-targeted Human Osteogenesis Imperfecta iPSCs

    Science.gov (United States)

    Deyle, David R; Khan, Iram F; Ren, Gaoying; Wang, Pei-Rong; Kho, Jordan; Schwarze, Ulrike; Russell, David W

    2012-01-01

    Osteogenesis imperfecta (OI) is caused by dominant mutations in the type I collagen genes. In principle, the skeletal abnormalities of OI could be treated by transplantation of patient-specific, bone-forming cells that no longer express the mutant gene. Here, we develop this approach by isolating mesenchymal cells from OI patients, inactivating their mutant collagen genes by adeno-associated virus (AAV)-mediated gene targeting, and deriving induced pluripotent stem cells (iPSCs) that were expanded and differentiated into mesenchymal stem cells (iMSCs). Gene-targeted iMSCs produced normal collagen and formed bone in vivo, but were less senescent and proliferated more than bone-derived MSCs. To generate iPSCs that would be more appropriate for clinical use, the reprogramming and selectable marker transgenes were removed by Cre recombinase. These results demonstrate that the combination of gene targeting and iPSC derivation can be used to produce potentially therapeutic cells from patients with genetic disease. PMID:22031238

  11. Myostatin induces interstitial fibrosis in the heart via TAK1 and p38.

    Science.gov (United States)

    Biesemann, Nadine; Mendler, Luca; Kostin, Sawa; Wietelmann, Astrid; Borchardt, Thilo; Braun, Thomas

    2015-09-01

    Myostatin, a member of the TGF-β superfamily of secreted growth factors, is a negative regulator of skeletal muscle growth. In the heart, it is expressed at lower levels compared to skeletal muscle but up-regulated under disease conditions. Cre recombinase-mediated inactivation of myostatin in adult cardiomyocytes leads to heart failure and increased mortality but cardiac function of surviving mice is restored after several weeks probably due to compensatory expression in non-cardiomyocytes. To study long-term effects of increased myostatin expression in the heart and to analyze the putative crosstalk between cardiomyocytes and fibroblasts, we overexpressed myostatin in cardiomyocytes. Increased expression of myostatin in heart muscle cells caused interstitial fibrosis via activation of the TAK-1-MKK3/6-p38 signaling pathway, compromising cardiac function in older mice. Our results uncover a novel role of myostatin in the heart and highlight the necessity for tight regulation of myostatin to maintain normal heart function.

  12. T-DNA transfer and T-DNA integration efficiencies upon Arabidopsis thaliana root explant cocultivation and floral dip transformation.

    Science.gov (United States)

    Ghedira, Rim; De Buck, Sylvie; Van Ex, Frédéric; Angenon, Geert; Depicker, Ann

    2013-12-01

    T-DNA transfer and integration frequencies during Agrobacterium-mediated root explant cocultivation and floral dip transformations of Arabidopsis thaliana were analyzed with and without selection for transformation-competent cells. Based on the presence or absence of CRE recombinase activity without or with the CRE T-DNA being integrated, transient expression versus stable transformation was differentiated. During root explant cocultivation, continuous light enhanced the number of plant cells competent for interaction with Agrobacterium and thus the number of transient gene expression events. However, in transformation competent plant cells, continuous light did not further enhance cotransfer or cointegration frequencies. Upon selection for root transformants expressing a first T-DNA, 43-69 % of these transformants showed cotransfer of another non-selected T-DNA in two different light regimes. However, integration of the non-selected cotransferred T-DNA occurred only in 19-46 % of these transformants, indicating that T-DNA integration in regenerating root cells limits the transformation frequencies. After floral dip transformation, transient T-DNA expression without integration could not be detected, while stable T-DNA transformation occurred in 0.5-1.3 % of the T1 seedlings. Upon selection for floral dip transformants with a first T-DNA, 8-34 % of the transformants showed cotransfer of the other non-selected T-DNA and in 93-100 % of them, the T-DNA was also integrated. Therefore, a productive interaction between the agrobacteria and the female gametophyte, rather than the T-DNA integration process, restricts the floral dip transformation frequencies.

  13. Myogenin regulates exercise capacity but is dispensable for skeletal muscle regeneration in adult mdx mice.

    Directory of Open Access Journals (Sweden)

    Eric Meadows

    Full Text Available Duchenne muscular dystrophy (DMD is the most prevalent inherited childhood muscle disorder in humans. mdx mice exhibit a similar pathophysiology to the human disorder allowing for an in-depth investigation of DMD. Myogenin, a myogenic regulatory factor, is best known for its role in embryonic myogenesis, but its role in adult muscle maintenance and regeneration is still poorly understood. Here, we generated an mdx:Myog(flox/flox mouse harboring a tamoxifen-inducible Cre recombinase transgene, which was used to conditionally delete Myog during adult life. After tamoxifen treatment, three groups of mice were created to study the effects of Myog deletion: mdx:Myog(flox/flox mice (mdx, Myog(flox/flox mice (wild-type, and mdx:Myog(floxΔ/floxΔ:Cre-ER mice (mdx:Myog-deleted. mdx:Myog-deleted mice exhibited no adverse phenotype and behaved normally. When run to exhaustion, mdx:Myog-deleted mice demonstrated an enhanced capacity for exercise compared to mdx mice, running nearly as far as wild-type mice. Moreover, these mice showed the same signature characteristics of muscle regeneration as mdx mice. Unexpectedly, we found that myogenin was dispensable for muscle regeneration. Factors associated with muscle fatigue, metabolism, and proteolysis were significantly altered in mdx:Myog-deleted mice, and this might contribute to their increased exercise capacity. Our results reveal novel functions for myogenin in adult muscle and suggest that reducing Myog expression in other muscle disease models may partially restore muscle function.

  14. Associations between Urinary Excretion of Cadmium and Renal Biomarkers in Nonsmoking Females: A Cross-Sectional Study in Rural Areas of South China

    Directory of Open Access Journals (Sweden)

    Yun-rui Zhang

    2015-09-01

    Full Text Available Objectives: The aim of this study was to systematically evaluate the relationship between urinary excretion of cadmium (U-Cd and biomarkers of renal dysfunction. Methods: One hundred eighty five non-smoking female farmers (aged from 44 to 71 years were recruited from two rural areas with different cadmium levels of exposure in southern China. Morning spot urine samples were collected for detecting U-Cd, urinary creatinine (U-cre, β2-microglobulin (β2-MG, α1-microglobulin (α1-MG, metallothionein (MT, retinol binding protein (RBP, albumin (AB, N-acetyl-β-D-glucosaminidase (NAG, alkaline phosphatase (ALP, γ-glutamyl transpeptidase (GGT and kidney injury molecule-1 (KIM-1. Spearman’s rank correlation was carried out to assess pairwise bivariate associations between continuous variables. Three different models of multiple linear regression (the cre-corrected, un-corrected and cre-adjusted model were used to model the dose-response relationships between U-Cd and nine urine markers. Results: Spearman’s rank correlation showed that NAG, ALP, RBP, β2-MG and MT were significantly associated with U-Cd for both cre-corrected and observed data. Generally, NAG correlated best with U-Cd among the nine biomarkers studied, followed by ALP and MT. In the un-corrected model and cre-adjusted model, the regression coefficients and R2 of nine biomarkers were larger than the corresponding values in the cre-corrected model, indicating that the use of observed data was better for investigating the relationship between biomarkers and U-Cd than cre-corrected data. Conclusions: Our results suggest that NAG, MT and ALP in urine were better biomarkers for long-term environmental cadmium exposure assessment among the nine biomarkers studied. Further, data without normalization with creatinine show better relationships between cadmium exposure and renal dysfunction.

  15. The Application of NHEJ-CRISPR/Cas9 and Cre-Lox System in the Generation of Bivalent Duck Enteritis Virus Vaccine against Avian Influenza Virus

    Directory of Open Access Journals (Sweden)

    Pengxiang Chang

    2018-02-01

    Full Text Available Duck-targeted vaccines to protect against avian influenza are critically needed to aid in influenza disease control efforts in regions where ducks are endemic for highly pathogenic avian influenza (HPAI. Duck enteritis virus (DEV is a promising candidate viral vector for development of vaccines targeting ducks, owing to its large genome and narrow host range. The clustered regularly interspaced palindromic repeats (CRISPR/Cas9 system is a versatile gene-editing tool that has proven beneficial for gene modification and construction of recombinant DNA viral vectored vaccines. Currently, there are two commonly used methods for gene insertion: non-homologous end-joining (NHEJ and homology-directed repair (HDR. Owing to its advantages in efficiency and independence from molecular requirements of the homologous arms, we utilized NHEJ-dependent CRISPR/Cas9 to insert the influenza hemagglutinin (HA antigen expression cassette into the DEV genome. The insert was initially tagged with reporter green fluorescence protein (GFP, and a Cre-Lox system was later used to remove the GFP gene insert. Furthermore, a universal donor plasmid system was established by introducing double bait sequences that were independent of the viral genome. In summary, we provide proof of principle for generating recombinant DEV viral vectored vaccines against the influenza virus using an integrated NHEJ-CRISPR/Cas9 and Cre-Lox system.

  16. Establishment of Cre-mediated HBV recombinant cccDNA (rcccDNA) cell line for cccDNA biology and antiviral screening assays.

    Science.gov (United States)

    Wu, Min; Li, Jin; Yue, Lei; Bai, Lu; Li, Yaming; Chen, Jieliang; Zhang, Xiaonan; Yuan, Zhenghong

    2018-04-01

    Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), existing in hepatocyte nuclei as a stable minichromosome, plays a central role in the life cycle of the virus and permits the persistence of infection. Despite being essential for HBV infection, little is known about the molecular mechanisms of cccDNA formation, regulation and degradation, and there is no therapeutic agents directly targeting cccDNA, fore mostly due to the lack of robust, reliable and quantifiable HBV cccDNA models. In this study, combined the Cre/loxP and sleeping beauty transposons system, we established HepG2-derived cell lines integrated with 2-60 copies of monomeric HBV genome flanked by loxP sites (HepG2-HBV/loxP). After Cre expression via adenoviral transduction, 3.3-kb recombinant cccDNA (rcccDNA) bearing a chimeric intron can be produced in the nuclei of these HepG2-HBV/loxP cells. The rcccDNA could be accurately quantified by quantitative PCR using specific primers and cccDNA pool generated in this model could be easily detected by Southern blotting using the digoxigenin probe system. We demonstrated that the rcccDNA was epigenetically organized as the natural minichromosome and served as the template supporting pgRNA transcription and viral replication. As the expression of HBV S antigen (HBsAg) is dependent on the newly generated cccDNA, HBsAg is the surrogate marker of cccDNA. Additionally, the efficacies of 3 classes of anti-HBV agents were evaluated in HepG2-HBV/loxP cells and antiviral activities with different mechanisms were confirmed. These data collectively suggested that HepG2-HBV/loxP cell system will be powerful platform for studying cccDNA related biological mechanisms and developing novel cccDNA targeting drugs. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Evaluation of dementia by acrolein, amyloid-β and creatinine.

    Science.gov (United States)

    Igarashi, Kazuei; Yoshida, Madoka; Waragai, Masaaki; Kashiwagi, Keiko

    2015-10-23

    Plasma, urine and cerebrospinal fluid (CSF) were examined for biochemical markers of dementia. Protein-conjugated acrolein (PC-Acro) and the amyloid-β (Aβ)40/42 ratio in plasma can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). In plasma, PC-Acro and the Aβ40/42 ratio in MCI and AD were significantly higher relative to non-demented subjects. Furthermore, urine acrolein metabolite, 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) and amino acid-conjugated acrolein (AC-Acro)/Cre in AD were significantly lower than MCI. It was also shown that reduced urine 3-HPMA/Cre correlated with increased plasma Aβ40/42 ratio in dementia. The Aβ40/PC-Acro ratio in CSF, together with Aβ40 and Aβ40/42 ratio, was lower in AD than MCI. Increased plasma PC-Acro and Aβ40/42 ratio and decreased urine 3-HPMA/Cre correlated with cognitive ability (MMSE). These results indicate that the measurements of acrolein derivatives together with Aβ and Cre in biologic fluids is useful to estimate severity of dementia. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Crystal Structure of the Phage T4 Recombinase UvsX and Its Functional Interaction with the T4 SF2 Helicase UvsW

    Energy Technology Data Exchange (ETDEWEB)

    Gajewski, Stefan; Webb, Michael R.; Galkin, Vitold; Egelman, Edward H.; Kreuzer, Kenneth N.; White, Stephen W. (Duke); (UV); (SJCH)

    2012-07-11

    Bacteriophage T4 provides an important model system for studying the mechanism of homologous recombination. We have determined the crystal structure of the T4 UvsX recombinase, and the overall architecture and fold closely resemble those of RecA, including a highly conserved ATP binding site. Based on this new structure, we reanalyzed electron microscopy reconstructions of UvsX-DNA filaments and docked the UvsX crystal structure into two different filament forms: a compressed filament generated in the presence of ADP and an elongated filament generated in the presence of ATP and aluminum fluoride. In these reconstructions, the ATP binding site sits at the protomer interface, as in the RecA filament crystal structure. However, the environment of the ATP binding site is altered in the two filament reconstructions, suggesting that nucleotide cannot be as easily accommodated at the protomer interface of the compressed filament. Finally, we show that the phage helicase UvsW completes the UvsX-promoted strand-exchange reaction, allowing the generation of a simple nicked circular product rather than complex networks of partially exchanged substrates.

  19. Krüppel-like Factor 5, Increased in Pancreatic Ductal Adenocarcinoma, Promotes Proliferation, Acinar-to-Ductal Metaplasia, Pancreatic Intraepithelial Neoplasia, and Tumor Growth in Mice.

    Science.gov (United States)

    He, Ping; Yang, Jong Won; Yang, Vincent W; Bialkowska, Agnieszka B

    2018-04-01

    Activating mutations in KRAS are detected in most pancreatic ductal adenocarcinomas (PDACs). Expression of an activated form of KRAS (KrasG12D) in pancreata of mice is sufficient to induce formation of pancreatic intraepithelial neoplasia (PanINs)-a precursor of PDAC. Pancreatitis increases formation of PanINs in mice that express KrasG12D by promoting acinar-to-ductal metaplasia (ADM). We investigated the role of the transcription factor Krüppel-like factor 5 (KLF5) in ADM and KRAS-mediated formation of PanINs. We performed studies in adult mice with conditional disruption of Klf5 (Klf5 fl/fl ) and/or expression of Kras G12D (LSL-Kras G12D ) via Cre ERTM recombinase regulated by an acinar cell-specific promoter (Ptf1a). Activation of Kras G12D and loss of KLF5 was achieved by administration of tamoxifen. Pancreatitis was induced in mice by administration of cerulein; pancreatic tissues were collected, analyzed by histology and immunohistochemistry, and transcriptomes were compared between mice that did or did not express KLF5. We performed immunohistochemical analyses of human tissue microarrays, comparing levels of KLF5 among 96 human samples of PDAC. UN-KC-6141 cells (pancreatic cancer cells derived from Pdx1-Cre;LSL-Kras G12D mice) were incubated with inhibitors of different kinases and analyzed in proliferation assays and by immunoblots. Expression of KLF5 was knocked down with small hairpin RNAs or CRISPR/Cas9 strategies; cells were analyzed in proliferation and gene expression assays, and compared with cells expressing control vectors. Cells were subcutaneously injected into flanks of syngeneic mice and tumor growth was assessed. Of the 96 PDAC samples analyzed, 73% were positive for KLF5 (defined as nuclear staining in more than 5% of tumor cells). Pancreata from Ptf1a-Cre ERTM ;LSL-Kras G12D mice contained ADM and PanIN lesions, which contained high levels of nuclear KLF5 within these structures. In contrast, Ptf1a-Cre ERTM ;LSL-Kras G12D ;Klf5 fl

  20. Efficient delivery of Cre-recombinase to neurons in vivo and stable transduction of neurons using adeno-associated and lentiviral vectors

    NARCIS (Netherlands)

    Ahmed, Bushra Y; Chakravarthy, Sridhara; Eggers, Ruben; Hermens, Wim T J M C; Zhang, Jing Ying; Niclou, Simone P; Levelt, Christiaan; Sablitzky, Fred; Anderson, Patrick N; Lieberman, A Robert; Verhaagen, J.

    2004-01-01

    BACKGROUND: Inactivating genes in vivo is an important technique for establishing their function in the adult nervous system. Unfortunately, conventional knockout mice may suffer from several limitations including embryonic or perinatal lethality and the compensatory regulation of other genes. One

  1. L-Rhamnose induction of Aspergillus nidulans α-L-rhamnosidase genes is glucose repressed via a CreA-independent mechanism acting at the level of inducer uptake

    Directory of Open Access Journals (Sweden)

    Tamayo-Ramos Juan A

    2012-02-01

    Full Text Available Abstract Background Little is known about the structure and regulation of fungal α-L-rhamnosidase genes despite increasing interest in the biotechnological potential of the enzymes that they encode. Whilst the paradigmatic filamentous fungus Aspergillus nidulans growing on L-rhamnose produces an α-L-rhamnosidase suitable for oenological applications, at least eight genes encoding putative α-L-rhamnosidases have been found in its genome. In the current work we have identified the gene (rhaE encoding the former activity, and characterization of its expression has revealed a novel regulatory mechanism. A shared pattern of expression has also been observed for a second α-L-rhamnosidase gene, (AN10277/rhaA. Results Amino acid sequence data for the oenological α-L-rhamnosidase were determined using MALDI-TOF mass spectrometry and correspond to the amino acid sequence deduced from AN7151 (rhaE. The cDNA of rhaE was expressed in Saccharomyces cerevisiae and yielded pNP-rhamnohydrolase activity. Phylogenetic analysis has revealed this eukaryotic α-L-rhamnosidase to be the first such enzyme found to be more closely related to bacterial rhamnosidases than other α-L-rhamnosidases of fungal origin. Northern analyses of diverse A. nidulans strains cultivated under different growth conditions indicate that rhaA and rhaE are induced by L-rhamnose and repressed by D-glucose as well as other carbon sources, some of which are considered to be non-repressive growth substrates. Interestingly, the transcriptional repression is independent of the wide domain carbon catabolite repressor CreA. Gene induction and glucose repression of these rha genes correlate with the uptake, or lack of it, of the inducing carbon source L-rhamnose, suggesting a prominent role for inducer exclusion in repression. Conclusions The A. nidulans rhaE gene encodes an α-L-rhamnosidase phylogenetically distant to those described in filamentous fungi, and its expression is regulated by a

  2. Glucose Transporter 3 Potentiates Degranulation and Is Required for Platelet Activation.

    Science.gov (United States)

    Fidler, Trevor P; Middleton, Elizabeth A; Rowley, Jesse W; Boudreau, Luc H; Campbell, Robert A; Souvenir, Rhonda; Funari, Trevor; Tessandier, Nicolas; Boilard, Eric; Weyrich, Andrew S; Abel, E Dale

    2017-09-01

    On activation, platelets increase glucose uptake, glycolysis, and glucose oxidation and consume stored glycogen. This correlation between glucose metabolism and platelet function is not well understood and even less is known about the role of glucose metabolism on platelet function in vivo. For glucose to enter a cell, it must be transported through glucose transporters. Here we evaluate the contribution of GLUT3 (glucose transporter 3) to platelet function to better understand glucose metabolism in platelets. Platelet-specific knockout of GLUT3 was generated by crossing mice harboring GLUT3 floxed allele to a PF4 (platelet factor 4)-driven Cre recombinase. In platelets, GLUT3 is localized primarily on α-granule membranes and under basal conditions facilitates glucose uptake into α-granules to be used for glycolysis. After activation, platelets degranulate and GLUT3 translocates to the plasma membrane, which is responsible for activation-mediated increased glucose uptake. In vivo, loss of GLUT3 in platelets increased survival in a collagen/epinephrine model of pulmonary embolism, and in a K/BxN model of autoimmune inflammatory disease, platelet-specific GLUT3 knockout mice display decreased disease progression. Mechanistically, loss of GLUT3 decreased platelet degranulation, spreading, and clot retraction. Decreased α-granule degranulation is due in part to an impaired ability of GLUT3 to potentiate exocytosis. GLUT3-mediated glucose utilization and glycogenolysis in platelets promotes α-granule release, platelet activation, and postactivation functions. © 2017 American Heart Association, Inc.

  3. GFAP-Cre-mediated transgenic activation of Bmi1 results in pituitary tumors.

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    Bart A Westerman

    Full Text Available Bmi1 is a member of the polycomb repressive complex 1 and plays different roles during embryonic development, depending on the developmental context. Bmi1 over expression is observed in many types of cancer, including tumors of astroglial and neural origin. Although genetic depletion of Bmi1 has been described to result in tumor inhibitory effects partly through INK4A/Arf mediated senescence and apoptosis and also through INK4A/Arf independent effects, it has not been proven that Bmi1 can be causally involved in the formation of these tumors. To see whether this is the case, we developed two conditional Bmi1 transgenic models that were crossed with GFAP-Cre mice to activate transgenic expression in neural and glial lineages. We show here that these mice generate intermediate and anterior lobe pituitary tumors that are positive for ACTH and beta-endorphin. Combined transgenic expression of Bmi1 together with conditional loss of Rb resulted in pituitary tumors but was insufficient to induce medulloblastoma therefore indicating that the oncogenic function of Bmi1 depends on regulation of p16(INK4A/Rb rather than on regulation of p19(ARF/p53. Human pituitary adenomas show Bmi1 overexpression in over 50% of the cases, which indicates that Bmi1 could be causally involved in formation of these tumors similarly as in our mouse model.

  4. Correlated motion of protein subdomains and large-scale conformational flexibility of RecA protein filament

    Science.gov (United States)

    Yu, Garmay; A, Shvetsov; D, Karelov; D, Lebedev; A, Radulescu; M, Petukhov; V, Isaev-Ivanov

    2012-02-01

    Based on X-ray crystallographic data available at Protein Data Bank, we have built molecular dynamics (MD) models of homologous recombinases RecA from E. coli and D. radiodurans. Functional form of RecA enzyme, which is known to be a long helical filament, was approximated by a trimer, simulated in periodic water box. The MD trajectories were analyzed in terms of large-scale conformational motions that could be detectable by neutron and X-ray scattering techniques. The analysis revealed that large-scale RecA monomer dynamics can be described in terms of relative motions of 7 subdomains. Motion of C-terminal domain was the major contributor to the overall dynamics of protein. Principal component analysis (PCA) of the MD trajectories in the atom coordinate space showed that rotation of C-domain is correlated with the conformational changes in the central domain and N-terminal domain, that forms the monomer-monomer interface. Thus, even though C-terminal domain is relatively far from the interface, its orientation is correlated with large-scale filament conformation. PCA of the trajectories in the main chain dihedral angle coordinate space implicates a co-existence of a several different large-scale conformations of the modeled trimer. In order to clarify the relationship of independent domain orientation with large-scale filament conformation, we have performed analysis of independent domain motion and its implications on the filament geometry.

  5. CRE Solvability, Nonlocal Symmetry and Exact Interaction Solutions of the Fifth-Order Modified Korteweg-de Vries Equation

    Science.gov (United States)

    Cheng, Wen-Guang; Qiu, De-Qin; Yu, Bo

    2017-06-01

    This paper is concerned with the fifth-order modified Korteweg-de Vries (fmKdV) equation. It is proved that the fmKdV equation is consistent Riccati expansion (CRE) solvable. Three special form of soliton-cnoidal wave interaction solutions are discussed analytically and shown graphically. Furthermore, based on the consistent tanh expansion (CTE) method, the nonlocal symmetry related to the consistent tanh expansion (CTE) is investigated, we also give the relationship between this kind of nonlocal symmetry and the residual symmetry which can be obtained with the truncated Painlevé method. We further study the spectral function symmetry and derive the Lax pair of the fmKdV equation. The residual symmetry can be localized to the Lie point symmetry of an enlarged system and the corresponding finite transformation group is computed. Supported by National Natural Science Foundation of China under Grant No. 11505090, and Research Award Foundation for Outstanding Young Scientists of Shandong Province under Grant No. BS2015SF009

  6. Development of myenteric cholinergic neurons in ChAT-Cre;R26R-YFP mice.

    Science.gov (United States)

    Hao, Marlene M; Bornstein, Joel C; Young, Heather M

    2013-10-01

    Cholinergic neurons are the major excitatory neurons of the enteric nervous system (ENS), and include intrinsic sensory neurons, interneurons, and excitatory motor neurons. Cholinergic neurons have been detected in the embryonic ENS; however, the development of these neurons has been difficult to study as they are difficult to detect prior to birth using conventional immunohistochemistry. In this study we used ChAT-Cre;R26R-YFP mice to examine the development of cholinergic neurons in the gut of embryonic and postnatal mice. Cholinergic (YFP+) neurons were first detected at embryonic day (E)11.5, and the proportion of cholinergic neurons gradually increased during pre- and postnatal development. At birth, myenteric cholinergic neurons comprised less than half of their adult proportions in the small intestine (25% of myenteric neurons were YFP+ at P0 compared to 62% in adults). The earliest cholinergic neurons appear to mainly project anally. Projections into the presumptive circular muscle were first observed at E14.5. A subpopulation of cholinergic neurons coexpress calbindin through embryonic and postnatal development, but only a small proportion coexpressed neuronal nitric oxide synthase. Our study shows that cholinergic neurons in the ENS develop over a protracted period of time. © 2013 Wiley Periodicals, Inc.

  7. Study of muscle cell dedifferentiation after skeletal muscle injury of mice with a Cre-Lox system.

    Science.gov (United States)

    Mu, Xiaodong; Peng, Hairong; Pan, Haiying; Huard, Johnny; Li, Yong

    2011-02-03

    Dedifferentiation of muscle cells in the tissue of mammals has yet to be observed. One of the challenges facing the study of skeletal muscle cell dedifferentiation is the availability of a reliable model that can confidentially distinguish differentiated cell populations of myotubes and non-fused mononuclear cells, including stem cells that can coexist within the population of cells being studied. In the current study, we created a Cre/Lox-β-galactosidase system, which can specifically tag differentiated multinuclear myotubes and myotube-generated mononuclear cells based on the activation of the marker gene, β-galactosidase. By using this system in an adult mouse model, we found that β-galactosidase positive mononuclear cells were generated from β-galactosidase positive multinuclear myofibers upon muscle injury. We also demonstrated that these mononuclear cells can develop into a variety of different muscle cell lineages, i.e., myoblasts, satellite cells, and muscle derived stem cells. These novel findings demonstrated, for the first time, that cellular dedifferentiation of skeletal muscle cells actually occurs in mammalian skeletal muscle following traumatic injury in vivo.

  8. A method for producing transgenic cells using a multi-integrase system on a human artificial chromosome vector.

    Directory of Open Access Journals (Sweden)

    Shigeyuki Yamaguchi

    Full Text Available The production of cells capable of expressing gene(s of interest is important for a variety of applications in biomedicine and biotechnology, including gene therapy and animal transgenesis. The ability to insert transgenes at a precise location in the genome, using site-specific recombinases such as Cre, FLP, and ΦC31, has major benefits for the efficiency of transgenesis. Recent work on integrases from ΦC31, R4, TP901-1 and Bxb1 phages demonstrated that these recombinases catalyze site-specific recombination in mammalian cells. In the present study, we examined the activities of integrases on site-specific recombination and gene expression in mammalian cells. We designed a human artificial chromosome (HAC vector containing five recombination sites (ΦC31 attP, R4 attP, TP901-1 attP, Bxb1 attP and FRT; multi-integrase HAC vector and de novo mammalian codon-optimized integrases. The multi-integrase HAC vector has several functions, including gene integration in a precise locus and avoiding genomic position effects; therefore, it was used as a platform to investigate integrase activities. Integrases carried out site-specific recombination at frequencies ranging from 39.3-96.8%. Additionally, we observed homogenous gene expression in 77.3-87.5% of colonies obtained using the multi-integrase HAC vector. This vector is also transferable to another cell line, and is capable of accepting genes of interest in this environment. These data suggest that integrases have high DNA recombination efficiencies in mammalian cells. The multi-integrase HAC vector enables us to produce transgene-expressing cells efficiently and create platform cell lines for gene expression.

  9. Rapid diagnosis of Theileria annulata by recombinase polymerase amplification combined with a lateral flow strip (LF-RPA) in epidemic regions.

    Science.gov (United States)

    Yin, Fangyuan; Liu, Junlong; Liu, Aihong; Li, Youquan; Luo, Jianxun; Guan, Guiquan; Yin, Hong

    2017-04-15

    Rapid and accurate diagnosis of Theileria annulata infection contributes to the formulation of strategies to eradicate this parasite. A simple and efficient diagnostic tool, recombinase polymerase amplification (RPA) combined with a lateral flow (LF) strip, was used in detection of Theileria and compared to other methods that require expensive instruments and skilled personnel. Herein, we established and optimized an LF-RPA method to detect the cytochrome b gene of T. annulata mitochondrial DNA from experimentally infected and field-collected blood samples. This method has many unparalleled characteristics, including that it is rapid (clear detection in 5min at constant temperature), sensitive (the limitation of detection is at least 2pg genomic DNA), and specific (no cross-reaction with other piroplasms that infect cattle). The LF-RPA assay was evaluated via testing 17 field blood samples and comparing the results of that of a PCR, showing 100% agreement, which demonstrates the ability of the LF-RPA assay to detect T. annulata infections in small number of samples (n=17). Taken together, the results indicate that this method could be used as an ideal diagnostic tool for detecting T. annulata in endemic regions with limited to fewer and local resources and could also be a potential technique for the surveillance and control of blood protozoa. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Disrupting the Indian hedgehog signaling pathway in vivo attenuates surgically induced osteoarthritis progression in Col2a1-CreERT2; Ihhfl/fl mice

    Science.gov (United States)

    2014-01-01

    Introduction Previous observations implicate Indian hedgehog (Ihh) signaling in osteoarthritis (OA) development because it regulates chondrocyte hypertrophy and matrix metallopeptidase 13 (MMP-13) expression. However, there is no direct genetic evidence for the role of Ihh in OA, because mice with cartilage or other tissue-specific deletion of the Ihh gene die shortly after birth. We evaluated the role of Ihh in vivo via a Cre-loxP-mediated approach to circumvent the early death caused by Ihh deficiency. Methods To evaluate the role of Ihh in OA development, Ihh was specifically deleted in murine cartilage using an Ihh conditional deletion construct (Col2a1-CreERT2; Ihhfl/fl). The extent of cartilage degradation and OA progression after Ihh deletion was assessed by histological analysis, immunohistochemistry, real-time PCR and in vivo fluorescence molecular tomography (FMT) 2 months after OA was induced by partial medial meniscectomy. The effect of Ihh signaling on cartilage was compared between Ihh-deleted mice and their control littermates. Results Only mild OA changes were observed in Ihh-deleted mice, while control mice displayed significantly more cartilage damage. Typical OA markers such as type X collagen and MMP-13 were decreased in Ihh-deleted mice. In vivo FMT demonstrated decreased cathepsins and MMP activity in knee joints of animals with deletion of Ihh. Conclusions These findings support the protective role of Ihh deletion in surgically induced OA. Thus, our findings suggest the potential to develop new therapeutic strategies that can prevent and treat OA by inhibiting Ihh signaling in chondrocytes. PMID:24428864

  11. Immunoregulatory actions of epithelial cell PPAR gamma at the colonic mucosa of mice with experimental inflammatory bowel disease.

    Science.gov (United States)

    Mohapatra, Saroj K; Guri, Amir J; Climent, Montse; Vives, Cristina; Carbo, Adria; Horne, William T; Hontecillas, Raquel; Bassaganya-Riera, Josep

    2010-04-20

    Peroxisome proliferator-activated receptors are nuclear receptors highly expressed in intestinal epithelial cells (IEC) and immune cells within the gut mucosa and are implicated in modulating inflammation and immune responses. The objective of this study was to investigate the effect of targeted deletion of PPAR gamma in IEC on progression of experimental inflammatory bowel disease (IBD). In the first phase, PPAR gamma flfl; Villin Cre- (VC-) and PPAR gamma flfl; Villin Cre+ (VC+) mice in a mixed FVB/C57BL/6 background were challenged with 2.5% dextran sodium sulfate (DSS) in drinking water for 0, 2, or 7 days. VC+ mice express a transgenic recombinase under the control of the Villin-Cre promoter that causes an IEC-specific deletion of PPAR gamma. In the second phase, we generated VC- and VC+ mice in a C57BL/6 background that were challenged with 2.5% DSS. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to phenotypically characterize lymphocyte and macrophage populations in blood, spleen and mesenteric lymph nodes. Global gene expression analysis was profiled using Affymetrix microarrays. The IEC-specific deficiency of PPAR gamma in mice with a mixed background worsened colonic inflammatory lesions, but had no effect on disease activity (DAI) or weight loss. In contrast, the IEC-specific PPAR gamma null mice in C57BL/6 background exhibited more severe inflammatory lesions, DAI and weight loss in comparison to their littermates expressing PPAR gamma in IEC. Global gene expression profiling revealed significantly down-regulated expression of lysosomal pathway genes and flow cytometry results demonstrated suppressed production of IL-10 by CD4+ T cells in mesenteric lymph nodes (MLN) of IEC-specific PPAR gamma null mice. Our results demonstrate that adequate expression of PPAR gamma in IEC is required for the regulation of mucosal immune responses and prevention of experimental IBD, possibly by modulation of

  12. Immunoregulatory actions of epithelial cell PPAR gamma at the colonic mucosa of mice with experimental inflammatory bowel disease.

    Directory of Open Access Journals (Sweden)

    Saroj K Mohapatra

    Full Text Available BACKGROUND: Peroxisome proliferator-activated receptors are nuclear receptors highly expressed in intestinal epithelial cells (IEC and immune cells within the gut mucosa and are implicated in modulating inflammation and immune responses. The objective of this study was to investigate the effect of targeted deletion of PPAR gamma in IEC on progression of experimental inflammatory bowel disease (IBD. METHODOLOGY/PRINCIPAL FINDINGS: In the first phase, PPAR gamma flfl; Villin Cre- (VC- and PPAR gamma flfl; Villin Cre+ (VC+ mice in a mixed FVB/C57BL/6 background were challenged with 2.5% dextran sodium sulfate (DSS in drinking water for 0, 2, or 7 days. VC+ mice express a transgenic recombinase under the control of the Villin-Cre promoter that causes an IEC-specific deletion of PPAR gamma. In the second phase, we generated VC- and VC+ mice in a C57BL/6 background that were challenged with 2.5% DSS. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to phenotypically characterize lymphocyte and macrophage populations in blood, spleen and mesenteric lymph nodes. Global gene expression analysis was profiled using Affymetrix microarrays. The IEC-specific deficiency of PPAR gamma in mice with a mixed background worsened colonic inflammatory lesions, but had no effect on disease activity (DAI or weight loss. In contrast, the IEC-specific PPAR gamma null mice in C57BL/6 background exhibited more severe inflammatory lesions, DAI and weight loss in comparison to their littermates expressing PPAR gamma in IEC. Global gene expression profiling revealed significantly down-regulated expression of lysosomal pathway genes and flow cytometry results demonstrated suppressed production of IL-10 by CD4+ T cells in mesenteric lymph nodes (MLN of IEC-specific PPAR gamma null mice. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that adequate expression of PPAR gamma in IEC is required for the regulation of mucosal

  13. Immunoregulatory Actions of Epithelial Cell PPAR γ at the Colonic Mucosa of Mice with Experimental Inflammatory Bowel Disease

    Science.gov (United States)

    Mohapatra, Saroj K.; Guri, Amir J.; Climent, Montse; Vives, Cristina; Carbo, Adria; Horne, William T.; Hontecillas, Raquel; Bassaganya-Riera, Josep

    2010-01-01

    Background Peroxisome proliferator-activated receptors are nuclear receptors highly expressed in intestinal epithelial cells (IEC) and immune cells within the gut mucosa and are implicated in modulating inflammation and immune responses. The objective of this study was to investigate the effect of targeted deletion of PPAR γ in IEC on progression of experimental inflammatory bowel disease (IBD). Methodology/Principal Findings In the first phase, PPAR γ flfl; Villin Cre- (VC-) and PPAR γ flfl; Villin Cre+ (VC+) mice in a mixed FVB/C57BL/6 background were challenged with 2.5% dextran sodium sulfate (DSS) in drinking water for 0, 2, or 7 days. VC+ mice express a transgenic recombinase under the control of the Villin-Cre promoter that causes an IEC-specific deletion of PPAR γ. In the second phase, we generated VC- and VC+ mice in a C57BL/6 background that were challenged with 2.5% DSS. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to phenotypically characterize lymphocyte and macrophage populations in blood, spleen and mesenteric lymph nodes. Global gene expression analysis was profiled using Affymetrix microarrays. The IEC-specific deficiency of PPAR γ in mice with a mixed background worsened colonic inflammatory lesions, but had no effect on disease activity (DAI) or weight loss. In contrast, the IEC-specific PPAR γ null mice in C57BL/6 background exhibited more severe inflammatory lesions, DAI and weight loss in comparison to their littermates expressing PPAR γ in IEC. Global gene expression profiling revealed significantly down-regulated expression of lysosomal pathway genes and flow cytometry results demonstrated suppressed production of IL-10 by CD4+ T cells in mesenteric lymph nodes (MLN) of IEC-specific PPAR γ null mice. Conclusions/Significance Our results demonstrate that adequate expression of PPAR γ in IEC is required for the regulation of mucosal immune responses and prevention of

  14. Pelvic Organ Support in Animals with Partial Loss of Fibulin-5 in the Vaginal Wall.

    Science.gov (United States)

    Chin, Kathleen; Wieslander, Cecilia; Shi, Haolin; Balgobin, Sunil; Montoya, T Ignacio; Yanagisawa, Hiromi; Word, R Ann

    2016-01-01

    Compromise of elastic fiber integrity in connective tissues of the pelvic floor is most likely acquired through aging, childbirth-associated injury, and genetic susceptibility. Mouse models of pelvic organ prolapse demonstrate systemic deficiencies in proteins that affect elastogenesis. Prolapse, however, does not occur until several months after birth and is thereby acquired with age or after parturition. To determine the impact of compromised levels of fibulin-5 (Fbln5) during adulthood on pelvic organ support after parturition and elastase-induced injury, tissue-specific conditional knockout (cKO) mice were generated in which doxycycline (dox) treatment results in deletion of Fbln5 in cells that utilize the smooth muscle α actin promoter-driven reverse tetracycline transactivator and tetracycline responsive element-Cre recombinase (i.e., Fbln5f/f/SMA++-rtTA/Cre+, cKO). Fbln5 was decreased significantly in the vagina of cKO mice compared with dox-treated wild type or controls (Fbln5f/f/SMA++-rtTA/Cre-/-). In controls, perineal body length (PBL) and bulge increased significantly after delivery but declined to baseline values within 6-8 weeks. Although overt prolapse did not occur in cKO animals, these transient increases in PBL postpartum were amplified and, unlike controls, parturition-induced increases in PBL (and bulge) did not recover to baseline but remained significantly increased for 12 wks. This lack of recovery from parturition was associated with increased MMP-9 and nondetectable levels of Fbln5 in the postpartum vagina. This predisposition to prolapse was accentuated by injection of elastase into the vaginal wall in which overt prolapse occurred in cKO animals, but rarely in controls. Taken together, our model system in which Fbln5 is conditionally knock-downed in stromal cells of the pelvic floor results in animals that undergo normal elastogenesis during development but lose Fbln5 as adults. The results indicate that vaginal fibulin-5 during

  15. Pelvic Organ Support in Animals with Partial Loss of Fibulin-5 in the Vaginal Wall.

    Directory of Open Access Journals (Sweden)

    Kathleen Chin

    Full Text Available Compromise of elastic fiber integrity in connective tissues of the pelvic floor is most likely acquired through aging, childbirth-associated injury, and genetic susceptibility. Mouse models of pelvic organ prolapse demonstrate systemic deficiencies in proteins that affect elastogenesis. Prolapse, however, does not occur until several months after birth and is thereby acquired with age or after parturition. To determine the impact of compromised levels of fibulin-5 (Fbln5 during adulthood on pelvic organ support after parturition and elastase-induced injury, tissue-specific conditional knockout (cKO mice were generated in which doxycycline (dox treatment results in deletion of Fbln5 in cells that utilize the smooth muscle α actin promoter-driven reverse tetracycline transactivator and tetracycline responsive element-Cre recombinase (i.e., Fbln5f/f/SMA++-rtTA/Cre+, cKO. Fbln5 was decreased significantly in the vagina of cKO mice compared with dox-treated wild type or controls (Fbln5f/f/SMA++-rtTA/Cre-/-. In controls, perineal body length (PBL and bulge increased significantly after delivery but declined to baseline values within 6-8 weeks. Although overt prolapse did not occur in cKO animals, these transient increases in PBL postpartum were amplified and, unlike controls, parturition-induced increases in PBL (and bulge did not recover to baseline but remained significantly increased for 12 wks. This lack of recovery from parturition was associated with increased MMP-9 and nondetectable levels of Fbln5 in the postpartum vagina. This predisposition to prolapse was accentuated by injection of elastase into the vaginal wall in which overt prolapse occurred in cKO animals, but rarely in controls. Taken together, our model system in which Fbln5 is conditionally knock-downed in stromal cells of the pelvic floor results in animals that undergo normal elastogenesis during development but lose Fbln5 as adults. The results indicate that vaginal fibulin-5

  16. Pelvic Organ Support in Animals with Partial Loss of Fibulin-5 in the Vaginal Wall

    Science.gov (United States)

    Shi, Haolin; Balgobin, Sunil; Montoya, T. Ignacio; Yanagisawa, Hiromi; Word, R. Ann

    2016-01-01

    Compromise of elastic fiber integrity in connective tissues of the pelvic floor is most likely acquired through aging, childbirth-associated injury, and genetic susceptibility. Mouse models of pelvic organ prolapse demonstrate systemic deficiencies in proteins that affect elastogenesis. Prolapse, however, does not occur until several months after birth and is thereby acquired with age or after parturition. To determine the impact of compromised levels of fibulin-5 (Fbln5) during adulthood on pelvic organ support after parturition and elastase-induced injury, tissue-specific conditional knockout (cKO) mice were generated in which doxycycline (dox) treatment results in deletion of Fbln5 in cells that utilize the smooth muscle α actin promoter-driven reverse tetracycline transactivator and tetracycline responsive element-Cre recombinase (i.e., Fbln5f/f/SMA++-rtTA/Cre+, cKO). Fbln5 was decreased significantly in the vagina of cKO mice compared with dox-treated wild type or controls (Fbln5f/f/SMA++-rtTA/Cre-/-). In controls, perineal body length (PBL) and bulge increased significantly after delivery but declined to baseline values within 6–8 weeks. Although overt prolapse did not occur in cKO animals, these transient increases in PBL postpartum were amplified and, unlike controls, parturition-induced increases in PBL (and bulge) did not recover to baseline but remained significantly increased for 12 wks. This lack of recovery from parturition was associated with increased MMP-9 and nondetectable levels of Fbln5 in the postpartum vagina. This predisposition to prolapse was accentuated by injection of elastase into the vaginal wall in which overt prolapse occurred in cKO animals, but rarely in controls. Taken together, our model system in which Fbln5 is conditionally knock-downed in stromal cells of the pelvic floor results in animals that undergo normal elastogenesis during development but lose Fbln5 as adults. The results indicate that vaginal fibulin-5 during

  17. High-grade serous carcinomas arise in the mouse oviduct via defects linked to the human disease.

    Science.gov (United States)

    Zhai, Yali; Wu, Rong; Kuick, Rork; Sessine, Michael S; Schulman, Stephanie; Green, Megan; Fearon, Eric R; Cho, Kathleen R

    2017-09-01

    Recent studies have suggested that the most common and lethal type of 'ovarian' cancer, i.e. high-grade serous carcinoma (HGSC), usually arises from epithelium on the fallopian tube fimbriae, and not from the ovarian surface epithelium. We have developed Ovgp1-iCreER T2 mice in which the Ovgp1 promoter controls expression of tamoxifen-regulated Cre recombinase in oviductal epithelium - the murine equivalent of human fallopian tube epithelium (FTE). We employed Ovgp1-iCreER T2 mice to show that FTE-specific inactivation of several different combinations of tumour suppressor genes that are recurrently mutated in human HGSCs - namely Brca1, Trp53, Rb1, and Nf1 - results in serous tubal intraepithelial carcinomas (STICs) that progress to HGSC or carcinosarcoma, and to widespread metastatic disease in a subset of mice. The cancer phenotype is highly penetrant and more rapid in mice carrying engineered alleles of all four tumour suppressor genes. Brca1, Trp53 and Pten inactivation in the oviduct also results in STICs and HGSCs, and is associated with diffuse epithelial hyperplasia and mucinous metaplasia, which are not observed in mice with intact Pten. Oviductal tumours arise earlier in these mice than in those with Brca1, Trp53, Rb1 and Nf1 inactivation. Tumour initiation and/or progression in mice lacking conditional Pten alleles probably require the acquisition of additional defects, a notion supported by our identification of loss of the wild-type Rb1 allele in the tumours of mice carrying only one floxed Rb1 allele. Collectively, the models closely recapitulate the heterogeneity and histological, genetic and biological features of human HGSC. These models should prove useful for studying the pathobiology and genetics of HGSC in vivo, and for testing new approaches for prevention, early detection, and treatment. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2017 Pathological Society of

  18. IGF-1 deficiency in a critical period early in life influences the vascular aging phenotype in mice by altering miRNA-mediated post-transcriptional gene regulation: implications for the developmental origins of health and disease hypothesis.

    Science.gov (United States)

    Tarantini, Stefano; Giles, Cory B; Wren, Jonathan D; Ashpole, Nicole M; Valcarcel-Ares, M Noa; Wei, Jeanne Y; Sonntag, William E; Ungvari, Zoltan; Csiszar, Anna

    2016-08-01

    Epidemiological findings support the concept of Developmental Origins of Health and Disease, suggesting that early-life hormonal influences during a sensitive period of development have a fundamental impact on vascular health later in life. The endocrine changes that occur during development are highly conserved across mammalian species and include dramatic increases in circulating IGF-1 levels during adolescence. The present study was designed to characterize the effect of developmental IGF-1 deficiency on the vascular aging phenotype. To achieve that goal, early-onset endocrine IGF-1 deficiency was induced in mice by knockdown of IGF-1 in the liver using Cre-lox technology (Igf1 f/f mice crossed with mice expressing albumin-driven Cre recombinase). This model exhibits low-circulating IGF-1 levels during the peripubertal phase of development, which is critical for the biology of aging. Due to the emergence of miRNAs as important regulators of the vascular aging phenotype, the effect of early-life IGF-1 deficiency on miRNA expression profile in the aorta was examined in animals at 27 months of age. We found that developmental IGF-1 deficiency elicits persisting late-life changes in miRNA expression in the vasculature, which significantly differed from those in mice with adult-onset IGF-1 deficiency (TBG-Cre-AAV8-mediated knockdown of IGF-1 at 5 month of age in Igf1 f/f mice). Using a novel computational approach, we identified miRNA target genes that are co-expressed with IGF-1 and associate with aging and vascular pathophysiology. We found that among the predicted targets, the expression of multiple extracellular matrix-related genes, including collagen-encoding genes, were downregulated in mice with developmental IGF-1 deficiency. Collectively, IGF-1 deficiency during a critical period during early in life results in persistent changes in post-transcriptional miRNA-mediated control of genes critical targets for vascular health, which likely contribute to the

  19. Conditional Viral Tract Tracing Delineates the Projections of the Distinct Kisspeptin Neuron Populations to Gonadotropin-Releasing Hormone (GnRH) Neurons in the Mouse.

    Science.gov (United States)

    Yip, Siew Hoong; Boehm, Ulrich; Herbison, Allan E; Campbell, Rebecca E

    2015-07-01

    Kisspeptin neurons play an essential role in the regulation of fertility through direct regulation of the GnRH neurons. However, the relative contributions of the two functionally distinct kisspeptin neuron subpopulations to this critical regulation are not fully understood. Here we analyzed the specific projection patterns of kisspeptin neurons originating from either the rostral periventricular nucleus of the third ventricle (RP3V) or the arcuate nucleus (ARN) using a cell-specific, viral-mediated tract-tracing approach. We stereotaxically injected a Cre-dependent recombinant adenovirus encoding farnesylated enhanced green fluorescent protein into the ARN or RP3V of adult male and female mice expressing Cre recombinase in kisspeptin neurons. Fibers from ARN kisspeptin neurons projected widely; however, we did not find any evidence for direct contact with GnRH neuron somata or proximal dendrites in either sex. In contrast, we identified RP3V kisspeptin fibers in close contact with GnRH neuron somata and dendrites in both sexes. Fibers originating from both the RP3V and ARN were observed in close contact with distal GnRH neuron processes in the ARN and in the lateral and internal aspects of the median eminence. Furthermore, GnRH nerve terminals were found in close contact with the proximal dendrites of ARN kisspeptin neurons in the ARN, and ARN kisspeptin fibers were found contacting RP3V kisspeptin neurons in both sexes. Together these data delineate selective zones of kisspeptin neuron inputs to GnRH neurons and demonstrate complex interconnections between the distinct kisspeptin populations and GnRH neurons.

  20. Lung-specific loss of α3 laminin worsens bleomycin-induced pulmonary fibrosis.

    Science.gov (United States)

    Morales-Nebreda, Luisa I; Rogel, Micah R; Eisenberg, Jessica L; Hamill, Kevin J; Soberanes, Saul; Nigdelioglu, Recep; Chi, Monica; Cho, Takugo; Radigan, Kathryn A; Ridge, Karen M; Misharin, Alexander V; Woychek, Alex; Hopkinson, Susan; Perlman, Harris; Mutlu, Gokhan M; Pardo, Annie; Selman, Moises; Jones, Jonathan C R; Budinger, G R Scott

    2015-04-01

    Laminins are heterotrimeric proteins that are secreted by the alveolar epithelium into the basement membrane, and their expression is altered in extracellular matrices from patients with pulmonary fibrosis. In a small number of patients with pulmonary fibrosis, we found that the normal basement membrane distribution of the α3 laminin subunit was lost in fibrotic regions of the lung. To determine if these changes play a causal role in the development of fibrosis, we generated mice lacking the α3 laminin subunit specifically in the lung epithelium by crossing mice expressing Cre recombinase driven by the surfactant protein C promoter (SPC-Cre) with mice expressing floxed alleles encoding the α3 laminin gene (Lama3(fl/fl)). These mice exhibited no developmental abnormalities in the lungs up to 6 months of age, but, compared with control mice, had worsened mortality, increased inflammation, and increased fibrosis after the intratracheal administration of bleomycin. Similarly, the severity of fibrosis induced by an adenovirus encoding an active form of transforming growth factor-β was worse in mice deficient in α3 laminin in the lung. Taken together, our results suggest that the loss of α3 laminin in the lung epithelium does not affect lung development, but plays a causal role in the development of fibrosis in response to bleomycin or adenovirally delivered transforming growth factor-β. Thus, we speculate that the loss of the normal basement membrane organization of α3 laminin that we observe in fibrotic regions from the lungs of patients with pulmonary fibrosis contributes to their disease progression.

  1. Reduced Erg Dosage Impairs Survival of Hematopoietic Stem and Progenitor Cells.

    Science.gov (United States)

    Xie, Ying; Koch, Mia Lee; Zhang, Xin; Hamblen, Melanie J; Godinho, Frank J; Fujiwara, Yuko; Xie, Huafeng; Klusmann, Jan-Henning; Orkin, Stuart H; Li, Zhe

    2017-07-01

    ERG, an ETS family transcription factor frequently overexpressed in human leukemia, has been implicated as a key regulator of hematopoietic stem cells. However, how ERG controls normal hematopoiesis, particularly at the stem and progenitor cell level, and how it contributes to leukemogenesis remain incompletely understood. Using homologous recombination, we generated an Erg knockdown allele (Erg kd ) in which Erg expression can be conditionally restored by Cre recombinase. Erg kd/kd animals die at E10.5-E11.5 due to defects in endothelial and hematopoietic cells, but can be completely rescued by Tie2-Cre-mediated restoration of Erg in these cells. In Erg kd/+ mice, ∼40% reduction in Erg dosage perturbs both fetal liver and bone marrow hematopoiesis by reducing the numbers of Lin - Sca-1 + c-Kit + (LSK) hematopoietic stem and progenitor cells (HSPCs) and megakaryocytic progenitors. By genetic mosaic analysis, we find that Erg-restored HSPCs outcompete Erg kd/+ HSPCs for contribution to adult hematopoiesis in vivo. This defect is in part due to increased apoptosis of HSPCs with reduced Erg dosage, a phenotype that becomes more drastic during 5-FU-induced stress hematopoiesis. Expression analysis reveals that reduced Erg expression leads to changes in expression of a subset of ERG target genes involved in regulating survival of HSPCs, including increased expression of a pro-apoptotic regulator Bcl2l11 (Bim) and reduced expression of Jun. Collectively, our data demonstrate that ERG controls survival of HSPCs, a property that may be used by leukemic cells. Stem Cells 2017;35:1773-1785. © 2017 AlphaMed Press.

  2. Hilar GABAergic interneuron activity controls spatial learning and memory retrieval.

    Directory of Open Access Journals (Sweden)

    Yaisa Andrews-Zwilling

    Full Text Available Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD, the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear.We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0--a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity.Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD.

  3. Oxytocin receptors are expressed on dopamine and glutamate neurons in the mouse ventral tegmental area that project to nucleus accumbens and other mesolimbic targets.

    Science.gov (United States)

    Peris, Joanna; MacFadyen, Kaley; Smith, Justin A; de Kloet, Annette D; Wang, Lei; Krause, Eric G

    2017-04-01

    The mesolimbic dopamine (DA) circuitry determines which behaviors are positively reinforcing and therefore should be encoded in the memory to become a part of the behavioral repertoire. Natural reinforcers, like food and sex, activate this pathway, thereby increasing the likelihood of further consummatory, social, and sexual behaviors. Oxytocin (OT) has been implicated in mediating natural reward and OT-synthesizing neurons project to the ventral tegmental area (VTA) and nucleus accumbens (NAc); however, direct neuroanatomical evidence of OT regulation of DA neurons within the VTA is sparse. To phenotype OT-receptor (OTR) expressing neurons originating within the VTA, we delivered Cre-inducible adeno-associated virus that drives the expression of fluorescent marker into the VTA of male mice that had Cre-recombinase driven by OTR gene expression. OTR-expressing VTA neurons project to NAc, prefrontal cortex, the extended amygdala, and other forebrain regions but less than 10% of these OTR-expressing neurons were identified as DA neurons (defined by tyrosine hydroxylase colocalization). Instead, almost 50% of OTR-expressing cells in the VTA were glutamate (GLU) neurons, as indicated by expression of mRNA for the vesicular GLU transporter (vGluT). About one-third of OTR-expressing VTA neurons did not colocalize with either DA or GLU phenotypic markers. Thus, OTR expression by VTA neurons implicates that OT regulation of reward circuitry is more complex than a direct action on DA neurotransmission. J. Comp. Neurol. 525:1094-1108, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. Double Dissociation of the Roles of Metabotropic Glutamate Receptor 5 and Oxytocin Receptor in Discrete Social Behaviors.

    Science.gov (United States)

    Mesic, Ivana; Guzman, Yomayra F; Guedea, Anita L; Jovasevic, Vladimir; Corcoran, Kevin A; Leaderbrand, Katherine; Nishimori, Katsuhiko; Contractor, Anis; Radulovic, Jelena

    2015-09-01

    Social interactions in vertebrates are complex phenomena based on affective and cognitive processes. Multiple brain regions and neurotransmitter systems are involved in the expression of social behaviors, but their individual roles in specific aspects of social interactions are not well understood. Here we investigated how Gq-protein-coupled metabotropic glutamate receptor 5 (mGluR5) and oxytocin receptor (Oxtr) affect social affiliation and social memory. We used conditional genetic approaches in which the genes coding for these receptors were knocked out in the lateral septum by infusion of recombinant adeno-associated viral vectors containing Cre recombinase (AAV-Cre). Social behavior was assessed 2 weeks later using a three-chamber paradigm for sociability and preference for social novelty. Septal deletion of mGluR5 abolished sociability while leaving preference for social novelty intact. In contrast, deletion of Oxtr did not affect sociability but significantly impaired preference for social novelty. Nonsocial behaviors or memories, including novel object recognition or fear conditioning, were not affected by these genetic manipulations. Immunohistochemical analyses of the distribution of mGluR5 and Oxtr revealed non-overlapping localization of these receptors within the lateral septum, suggesting that not only different neurotransmitters but also different neuronal types contribute to sociability versus preference for social novelty. Our findings identify highly specialized roles of lateral septal mGluR5 and Oxtr in the the regulation of discrete social behaviors, and suggest that deficits in social interactions, which accompany many mental illnesses, would benefit from comprehensive treatments targeting different components of social functioning.

  5. Design of potent inhibitors of human RAD51 recombinase based on BRC motifs of BRCA2 protein: modeling and experimental validation of a chimera peptide.

    KAUST Repository

    Nomme, Julian; Renodon-Corniè re, Axelle; Asanomi, Yuya; Sakaguchi, Kazuyasu; Stasiak, Alicja Z; Stasiak, Andrzej; Norden, Bengt; Tran, Vinh; Takahashi, Masayuki

    2010-01-01

    We have previously shown that a 28-amino acid peptide derived from the BRC4 motif of BRCA2 tumor suppressor inhibits selectively human RAD51 recombinase (HsRad51). With the aim of designing better inhibitors for cancer treatment, we combined an in silico docking approach with in vitro biochemical testing to construct a highly efficient chimera peptide from eight existing human BRC motifs. We built a molecular model of all BRC motifs complexed with HsRad51 based on the crystal structure of the BRC4 motif-HsRad51 complex, computed the interaction energy of each residue in each BRC motif, and selected the best amino acid residue at each binding position. This analysis enabled us to propose four amino acid substitutions in the BRC4 motif. Three of these increased the inhibitory effect in vitro, and this effect was found to be additive. We thus obtained a peptide that is about 10 times more efficient in inhibiting HsRad51-ssDNA complex formation than the original peptide.

  6. Design of potent inhibitors of human RAD51 recombinase based on BRC motifs of BRCA2 protein: modeling and experimental validation of a chimera peptide.

    KAUST Repository

    Nomme, Julian

    2010-08-01

    We have previously shown that a 28-amino acid peptide derived from the BRC4 motif of BRCA2 tumor suppressor inhibits selectively human RAD51 recombinase (HsRad51). With the aim of designing better inhibitors for cancer treatment, we combined an in silico docking approach with in vitro biochemical testing to construct a highly efficient chimera peptide from eight existing human BRC motifs. We built a molecular model of all BRC motifs complexed with HsRad51 based on the crystal structure of the BRC4 motif-HsRad51 complex, computed the interaction energy of each residue in each BRC motif, and selected the best amino acid residue at each binding position. This analysis enabled us to propose four amino acid substitutions in the BRC4 motif. Three of these increased the inhibitory effect in vitro, and this effect was found to be additive. We thus obtained a peptide that is about 10 times more efficient in inhibiting HsRad51-ssDNA complex formation than the original peptide.

  7. Cytosolic antibody delivery by lipid-sensitive endosomolytic peptide

    Science.gov (United States)

    Akishiba, Misao; Takeuchi, Toshihide; Kawaguchi, Yoshimasa; Sakamoto, Kentarou; Yu, Hao-Hsin; Nakase, Ikuhiko; Takatani-Nakase, Tomoka; Madani, Fatemeh; Gräslund, Astrid; Futaki, Shiroh

    2017-08-01

    One of the major obstacles in intracellular targeting using antibodies is their limited release from endosomes into the cytosol. Here we report an approach to deliver proteins, which include antibodies, into cells by using endosomolytic peptides derived from the cationic and membrane-lytic spider venom peptide M-lycotoxin. The delivery peptides were developed by introducing one or two glutamic acid residues into the hydrophobic face. One peptide with the substitution of leucine by glutamic acid (L17E) was shown to enable a marked cytosolic liberation of antibodies (immunoglobulins G (IgGs)) from endosomes. The predominant membrane-perturbation mechanism of this peptide is the preferential disruption of negatively charged membranes (endosomal membranes) over neutral membranes (plasma membranes), and the endosomolytic peptide promotes the uptake by inducing macropinocytosis. The fidelity of this approach was confirmed through the intracellular delivery of a ribosome-inactivation protein (saporin), Cre recombinase and IgG delivery, which resulted in a specific labelling of the cytosolic proteins and subsequent suppression of the glucocorticoid receptor-mediated transcription. We also demonstrate the L17E-mediated cytosolic delivery of exosome-encapsulated proteins.

  8. Mutant TDP-43 within motor neurons drives disease onset but not progression in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Ditsworth, Dara; Maldonado, Marcus; McAlonis-Downes, Melissa; Sun, Shuying; Seelman, Amanda; Drenner, Kevin; Arnold, Eveline; Ling, Shuo-Chien; Pizzo, Donald; Ravits, John; Cleveland, Don W; Da Cruz, Sandrine

    2017-06-01

    Mutations in TDP-43 cause amyotrophic lateral sclerosis (ALS), a fatal paralytic disease characterized by degeneration and premature death of motor neurons. The contribution of mutant TDP-43-mediated damage within motor neurons was evaluated using mice expressing a conditional allele of an ALS-causing TDP-43 mutant (Q331K) whose broad expression throughout the central nervous system mimics endogenous TDP-43. TDP-43 Q331K mice develop age- and mutant-dependent motor deficits from degeneration and death of motor neurons. Cre-recombinase-mediated excision of the TDP-43 Q331K gene from motor neurons is shown to delay onset of motor symptoms and appearance of TDP-43-mediated aberrant nuclear morphology, and abrogate subsequent death of motor neurons. However, reduction of mutant TDP-43 selectively in motor neurons did not prevent age-dependent degeneration of axons and neuromuscular junction loss, nor did it attenuate astrogliosis or microgliosis. Thus, disease mechanism is non-cell autonomous with mutant TDP-43 expressed in motor neurons determining disease onset but progression defined by mutant acting within other cell types.

  9. Club cells surviving influenza A virus infection induce temporary nonspecific antiviral immunity.

    Science.gov (United States)

    Hamilton, Jennifer R; Sachs, David; Lim, Jean K; Langlois, Ryan A; Palese, Peter; Heaton, Nicholas S

    2016-04-05

    A brief window of antigen-nonspecific protection has been observed after influenza A virus (IAV) infection. Although this temporary immunity has been assumed to be the result of residual nonspecific inflammation, this period of induced immunity has not been fully studied. Because IAV has long been characterized as a cytopathic virus (based on its ability to rapidly lyse most cell types in culture), it has been a forgone conclusion that directly infected cells could not be contributing to this effect. Using a Cre recombinase-expressing IAV, we have previously shown that club cells can survive direct viral infection. We show here not only that these cells can eliminate all traces of the virus and survive but also that they acquire a heightened antiviral response phenotype after surviving. Moreover, we experimentally demonstrate temporary nonspecific viral immunity after IAV infection and show that surviving cells are required for this phenotype. This work characterizes a virally induced modulation of the innate immune response that may represent a new mechanism to prevent viral diseases.

  10. Deletion of Munc18-1 in 5-HT neurons results in rapid degeneration of the 5-HT system and early postnatal lethality.

    Directory of Open Access Journals (Sweden)

    Jacobus J Dudok

    Full Text Available The serotonin (5-HT system densely innervates many brain areas and is important for proper brain development. To specifically ablate the 5-HT system we generated mutant mice carrying a floxed Munc18-1 gene and Cre recombinase driven by the 5-HT-specific serotonin reuptake transporter (SERT promoter. The majority of mutant mice died within a few days after birth. Immunohistochemical analysis of brains of these mice showed that initially 5-HT neurons are formed and the cortex is innervated with 5-HT projections. From embryonic day 16 onwards, however, 5-HT neurons started to degenerate and at postnatal day 2 hardly any 5-HT projections were present in the cortex. The 5-HT system of mice heterozygous for the floxed Munc18-1 allele was indistinguishable from control mice. These data show that deletion of Munc18-1 in 5-HT neurons results in rapid degeneration of the 5-HT system and suggests that the 5-HT system is important for postnatal survival.

  11. Conditional expression of Pomc in the Lepr-positive subpopulation of POMC neurons is sufficient for normal energy homeostasis and metabolism.

    Science.gov (United States)

    Lam, Daniel D; Attard, Courtney A; Mercer, Aaron J; Myers, Martin G; Rubinstein, Marcelo; Low, Malcolm J

    2015-04-01

    Peptides derived from the proopiomelanocortin (POMC) precursor are critical for the normal regulation of many physiological parameters, and POMC deficiency results in severe obesity and metabolic dysfunction. Conversely, augmentation of central nervous system melanocortin function is a promising therapeutic avenue for obesity and diabetes but is confounded by detrimental cardiovascular effects including hypertension. Because the hypothalamic population of POMC-expressing neurons is neurochemically and neuroanatomically heterogeneous, there is interest in the possible dissociation of functionally distinct POMC neuron subpopulations. We used a Cre recombinase-dependent and hypothalamus-specific reactivatable PomcNEO allele to restrict Pomc expression to hypothalamic neurons expressing leptin receptor (Lepr) in mice. In contrast to mice with total hypothalamic Pomc deficiency, which are severely obese, mice with Lepr-restricted Pomc expression displayed fully normal body weight, food consumption, glucose homeostasis, and locomotor activity. Thus, Lepr+ POMC neurons, which constitute approximately two-thirds of the total POMC neuron population, are sufficient for normal regulation of these parameters. This functional dissociation approach represents a promising avenue for isolating therapeutically relevant POMC neuron subpopulations.

  12. A set of vectors for introduction of antibiotic resistance genes by in vitro Cre-mediated recombination

    Directory of Open Access Journals (Sweden)

    Vassetzky Yegor S

    2008-12-01

    Full Text Available Abstract Background Introduction of new antibiotic resistance genes in the plasmids of interest is a frequent task in molecular cloning practice. Classical approaches involving digestion with restriction endonucleases and ligation are time-consuming. Findings We have created a set of insertion vectors (pINS carrying genes that provide resistance to various antibiotics (puromycin, blasticidin and G418 and containing a loxP site. Each vector (pINS-Puro, pINS-Blast or pINS-Neo contains either a chloramphenicol or a kanamycin resistance gene and is unable to replicate in most E. coli strains as it contains a conditional R6Kγ replication origin. Introduction of the antibiotic resistance genes into the vector of interest is achieved by Cre-mediated recombination between the replication-incompetent pINS and a replication-competent target vector. The recombination mix is then transformed into E. coli and selected by the resistance marker (kanamycin or chloramphenicol present in pINS, which allows to recover the recombinant plasmids with 100% efficiency. Conclusion Here we propose a simple strategy that allows to introduce various antibiotic-resistance genes into any plasmid containing a replication origin, an ampicillin resistance gene and a loxP site.

  13. Three dimensional proton MR spectroscopic imaging in transition zone prostate cancer

    International Nuclear Information System (INIS)

    Yang Yi; Zhao Wenlu; Shen Junkang

    2012-01-01

    Objective: To discuss the clinical value of three dimensional proton MR spectroscopic imaging (3D 1 HMRSI) in the detection of transition zone (TZ) prorate cancer and evaluate the feasibility of 3D 1 HMRSI for determining the aggressiveness of TZ cancer by analyzing its metabolic characteristics. Methods: The 3D 1 HMRSI data of sixty patients suspected TZ cancer in conventional MR examinations were retrospectively analyzed. The values of (Cho + Cre)/Cit of TZ cancer and benign prostatic hyperplasia (BPH) voxels were recorded and compared using independent sample t' test, and the area under the ROC curve was used to evaluate the diagnostic accuracy. Based on Gleason scores, TZ cancer voxels were divided into three groups,including low-risk (Gleason score <7), intermediate-risk (Gleason score =7) and high-risk (Gleason score >7). The values of (Cho + Cre)/Cit were compared among the three groups using Kruskal-Wallis test. The correlation of the value of (Cho + Cre)/Cit and Gleason score was analyzed using rank correlation analysis. Results: Among the 60 patients, histopathology confirmed TZ cancer in 25 patients and BPH in 35 patients. The inversion of Cho and Cit peak value with increased (Cho + Cre)/Cit was detected in 160 out of 177 TZ cancer voxels. Most spectral curves of the 517 BPH voxels were similar with that of normal peripheral zone on 1 HMRSI. The mean values of (Cho + Cre)/Cit of TZ cancer and BPH voxels were 2.17 ± 1.29 and 0.77 ± 0.20, respectively, with significant difference between them (t'=14.38, P<0.01). Using (Cho + Cre)/Cit for distinguishing TZ cancer, the area under ROC curve was 0.985 (P<0.01).With the cut-off point 1.08, the sensitivity, specificity and accuracy of TZ cancer diagnosis was 92.7%, 94.2% and 93.8%, respectively. The number of low-risk, intermediate-risk and high-risk TZ cancer voxels were 57, 64 and 56 respectively, and the mean values of (Cho + Cre)/Cit of the three groups were 1.43 (1.16-1.87), 1.66 (1

  14. A field based detection method for Rose rosette virus using isothermal probe-based Reverse transcription-recombinase polymerase amplification assay.

    Science.gov (United States)

    Babu, Binoy; Washburn, Brian K; Ertek, Tülin Sarigül; Miller, Steven H; Riddle, Charles B; Knox, Gary W; Ochoa-Corona, Francisco M; Olson, Jennifer; Katırcıoğlu, Yakup Zekai; Paret, Mathews L

    2017-09-01

    Rose rosette disease, caused by Rose rosette virus (RRV; genus Emaravirus) is a major threat to the rose industry in the U.S. The only strategy currently available for disease management is early detection and eradication of the infected plants, thereby limiting its potential spread. Current RT-PCR based diagnostic methods for RRV are time consuming and are inconsistent in detecting the virus from symptomatic plants. Real-time RT-qPCR assay is highly sensitive for detection of RRV, but it is expensive and requires well-equipped laboratories. Both the RT-PCR and RT-qPCR cannot be used in a field-based testing for RRV. Hence a novel probe based, isothermal reverse transcription-recombinase polymerase amplification (RT-exoRPA) assay, using primer/probe designed based on the nucleocapsid gene of the RRV has been developed. The assay is highly specific and did not give a positive reaction to other viruses infecting roses belonging to both inclusive and exclusive genus. Dilution assays using the in vitro transcript showed that the primer/probe set is highly sensitive, with a detection limit of 1 fg/μl. In addition, a rapid technique for the extraction of viral RNA (rose varieties, collected from different states in the U.S. The entire process, including the extraction can be completed in 25min, with less sophisticated equipments. The developed assay can be used with high efficiency in large scale field testing for rapid detection of RRV in commercial nurseries and landscapes. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Conditional loss of heparin-binding EGF-like growth factor results in enhanced liver fibrosis after bile duct ligation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Takemura, Takayo; Yoshida, Yuichi [Department of Gastroenterology and Hepatology, Osaka University, Graduate School of Medicine, Osaka (Japan); Kiso, Shinichi, E-mail: kiso@gh.med.osaka-u.ac.jp [Department of Gastroenterology and Hepatology, Osaka University, Graduate School of Medicine, Osaka (Japan); Kizu, Takashi; Furuta, Kunimaro; Ezaki, Hisao; Hamano, Mina; Egawa, Mayumi; Chatani, Norihiro; Kamada, Yoshihiro [Department of Gastroenterology and Hepatology, Osaka University, Graduate School of Medicine, Osaka (Japan); Imai, Yasuharu [Department of Gastroenterology, Ikeda Municipal Hospital, Ikeda, Osaka (Japan); Higashiyama, Shigeki [Department of Biochemistry and Molecular Genetics, Ehime University, Graduate School of Medicine and Department of Cell Growth and Tumor Regulation, Proteo-Medicine Research Center (ProMRes), Ehime University, Shitsukawa, Toon, Ehime (Japan); Iwamoto, Ryo; Mekada, Eisuke [Department of Cell Biology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka (Japan); Takehara, Tetsuo [Department of Gastroenterology and Hepatology, Osaka University, Graduate School of Medicine, Osaka (Japan)

    2013-07-26

    Highlights: •HB-EGF expression was increased during the development of liver fibrosis. •Conditional HB-EGF knockout mouse showed enhanced experimental liver fibrosis. •HB-EGF antagonized TGF-β-induced activation of hepatic stellate cells. •We report a possible protective role of HB-EGF in cholestatic liver fibrosis. -- Abstract: Our aims were to evaluate the involvement of heparin-binding EGF-like growth factor (HB-EGF) in liver fibrogenesis of humans and mice and to elucidate the effect of HB-EGF deficiency on cholestatic liver fibrosis using conditional HB-EGF knockout (KO) mice. We first demonstrated that gene expression of HB-EGF had a positive significant correlation with that of collagen in human fibrotic livers, and was increased in bile duct ligation (BDL)-induced fibrotic livers in mouse. We then generated conditional HB-EGF knockout (KO) mice using the interferon inducible Mx-1 promoter driven Cre recombinase transgene and wild type (WT) and KO mice were subjected to BDL. After BDL, KO mice exhibited enhanced liver fibrosis with increased expression of collagen, compared with WT mice. Finally, we used mouse hepatic stellate cells (HSCs) to examine the role of HB-EGF in the activation of these cells and showed that HB-EGF antagonized TGF-β-induced gene expression of collagen in mouse primary HSCs. Interestingly, HB-EGF did not prevent the TGF-β-induced nuclear accumulation of Smad3, but did lead to stabilization of the Smad transcriptional co-repressor TG-interacting factor. In conclusion, our data suggest a possible protective role of HB-EGF in cholestatic liver fibrosis.

  16. Conditional loss of heparin-binding EGF-like growth factor results in enhanced liver fibrosis after bile duct ligation in mice

    International Nuclear Information System (INIS)

    Takemura, Takayo; Yoshida, Yuichi; Kiso, Shinichi; Kizu, Takashi; Furuta, Kunimaro; Ezaki, Hisao; Hamano, Mina; Egawa, Mayumi; Chatani, Norihiro; Kamada, Yoshihiro; Imai, Yasuharu; Higashiyama, Shigeki; Iwamoto, Ryo; Mekada, Eisuke; Takehara, Tetsuo

    2013-01-01

    Highlights: •HB-EGF expression was increased during the development of liver fibrosis. •Conditional HB-EGF knockout mouse showed enhanced experimental liver fibrosis. •HB-EGF antagonized TGF-β-induced activation of hepatic stellate cells. •We report a possible protective role of HB-EGF in cholestatic liver fibrosis. -- Abstract: Our aims were to evaluate the involvement of heparin-binding EGF-like growth factor (HB-EGF) in liver fibrogenesis of humans and mice and to elucidate the effect of HB-EGF deficiency on cholestatic liver fibrosis using conditional HB-EGF knockout (KO) mice. We first demonstrated that gene expression of HB-EGF had a positive significant correlation with that of collagen in human fibrotic livers, and was increased in bile duct ligation (BDL)-induced fibrotic livers in mouse. We then generated conditional HB-EGF knockout (KO) mice using the interferon inducible Mx-1 promoter driven Cre recombinase transgene and wild type (WT) and KO mice were subjected to BDL. After BDL, KO mice exhibited enhanced liver fibrosis with increased expression of collagen, compared with WT mice. Finally, we used mouse hepatic stellate cells (HSCs) to examine the role of HB-EGF in the activation of these cells and showed that HB-EGF antagonized TGF-β-induced gene expression of collagen in mouse primary HSCs. Interestingly, HB-EGF did not prevent the TGF-β-induced nuclear accumulation of Smad3, but did lead to stabilization of the Smad transcriptional co-repressor TG-interacting factor. In conclusion, our data suggest a possible protective role of HB-EGF in cholestatic liver fibrosis

  17. Information filtering based on corrected redundancy-eliminating mass diffusion.

    Science.gov (United States)

    Zhu, Xuzhen; Yang, Yujie; Chen, Guilin; Medo, Matus; Tian, Hui; Cai, Shi-Min

    2017-01-01

    Methods used in information filtering and recommendation often rely on quantifying the similarity between objects or users. The used similarity metrics often suffer from similarity redundancies arising from correlations between objects' attributes. Based on an unweighted undirected object-user bipartite network, we propose a Corrected Redundancy-Eliminating similarity index (CRE) which is based on a spreading process on the network. Extensive experiments on three benchmark data sets-Movilens, Netflix and Amazon-show that when used in recommendation, the CRE yields significant improvements in terms of recommendation accuracy and diversity. A detailed analysis is presented to unveil the origins of the observed differences between the CRE and mainstream similarity indices.

  18. Astrocytic β2 Adrenergic Receptor Gene Deletion Affects Memory in Aged Mice.

    Directory of Open Access Journals (Sweden)

    Cathy Joanna Jensen

    Full Text Available In vitro and in vivo studies suggest that the astrocytic adrenergic signalling enhances glycogenolysis which provides energy to be transported to nearby cells and in the form of lactate. This energy source is important for motor and cognitive functioning. While it is suspected that the β2-adrenergic receptor on astrocytes might contribute to this energy balance, it has not yet been shown conclusively in vivo. Inducible astrocyte specific β2-adrenergic receptor knock-out mice were generated by crossing homozygous β2-adrenergic receptor floxed mice (Adrb2flox and mice with heterozygous tamoxifen-inducible Cre recombinase-expression driven by the astrocyte specific L-glutamate/L-aspartate transporter promoter (GLAST-CreERT2. Assessments using the modified SHIRPA (SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment test battery, swimming ability test, and accelerating rotarod test, performed at 1, 2 and 4 weeks, 6 and 12 months after tamoxifen (or vehicle administration did not reveal any differences in physical health or motor functions between the knock-out mice and controls. However deficits were found in the cognitive ability of aged, but not young adult mice, reflected in impaired learning in the Morris Water Maze. Similarly, long-term potentiation (LTP was impaired in hippocampal brain slices of aged knock-out mice maintained in low glucose media. Using microdialysis in cerebellar white matter we found no significant differences in extracellular lactate or glucose between the young adult knock-out mice and controls, although trends were detected. Our results suggest that β2-adrenergic receptor expression on astrocytes in mice may be important for maintaining cognitive health at advanced age, but is dispensable for motor function.

  19. Hilar GABAergic Interneuron Activity Controls Spatial Learning and Memory Retrieval

    Science.gov (United States)

    Andrews-Zwilling, Yaisa; Gillespie, Anna K.; Kravitz, Alexxai V.; Nelson, Alexandra B.; Devidze, Nino; Lo, Iris; Yoon, Seo Yeon; Bien-Ly, Nga; Ring, Karen; Zwilling, Daniel; Potter, Gregory B.; Rubenstein, John L. R.; Kreitzer, Anatol C.; Huang, Yadong

    2012-01-01

    Background Although extensive research has demonstrated the importance of excitatory granule neurons in the dentate gyrus of the hippocampus in normal learning and memory and in the pathogenesis of amnesia in Alzheimer's disease (AD), the role of hilar GABAergic inhibitory interneurons, which control the granule neuron activity, remains unclear. Methodology and Principal Findings We explored the function of hilar GABAergic interneurons in spatial learning and memory by inhibiting their activity through Cre-dependent viral expression of enhanced halorhodopsin (eNpHR3.0)—a light-driven chloride pump. Hilar GABAergic interneuron-specific expression of eNpHR3.0 was achieved by bilaterally injecting adeno-associated virus containing a double-floxed inverted open-reading frame encoding eNpHR3.0 into the hilus of the dentate gyrus of mice expressing Cre recombinase under the control of an enhancer specific for GABAergic interneurons. In vitro and in vivo illumination with a yellow laser elicited inhibition of hilar GABAergic interneurons and consequent activation of dentate granule neurons, without affecting pyramidal neurons in the CA3 and CA1 regions of the hippocampus. We found that optogenetic inhibition of hilar GABAergic interneuron activity impaired spatial learning and memory retrieval, without affecting memory retention, as determined in the Morris water maze test. Importantly, optogenetic inhibition of hilar GABAergic interneuron activity did not alter short-term working memory, motor coordination, or exploratory activity. Conclusions and Significance Our findings establish a critical role for hilar GABAergic interneuron activity in controlling spatial learning and memory retrieval and provide evidence for the potential contribution of GABAergic interneuron impairment to the pathogenesis of amnesia in AD. PMID:22792368

  20. Distribution and compartmental organization of GABAergic medium-sized spiny neurons in the mouse Nucleus Accumbens

    Directory of Open Access Journals (Sweden)

    Giuseppe eGangarossa

    2013-02-01

    Full Text Available The nucleus accumbens (NAc is a critical brain region involved in many reward-related behaviors. The NAc comprises major compartments the core and the shell, which encompass several subterritories. GABAergic medium-sized spiny neurons (MSNs constitute the output neurons of the NAc core and shell. While the functional organization of the NAc core outputs resembles the one described for the dorsal striatum, a simple classification of the NAc shell neurons has been difficult to define due to the complexity of the compartmental segregation of cells. We used a variety of BAC transgenic mice expressing enhanced green fluorescence (EGFP or the Cre-recombinase (Cre under the control of the promoter of dopamine D1, D2, and D3 receptors and of adenosine A2a receptor to dissect the microanatomy of the NAc. Moreover, using various immunological markers we characterized in detail the distribution of MSNs in the mouse NAc. In addition, cell-type specific ERK phosphorylation in the NAc subterritories was analyzed following acute administration of SKF81297 (a D1R-like agonist, quinpirole (a D2R-like agonist, apomorphine (a non-selective DA receptor agonist, raclopride (a D2R-like antagonist, and psychostimulant drugs, including cocaine and d-amphetamine. Each drug generated a unique topography and cell-type specific activation of ERK in the NAc. Our results show the existence of marked differences in the receptor expression pattern and functional activation of MSNs within the shell subterritories. This study emphasizes the anatomical and functional heterogeneity of the NAc, which will have to be considered in its further study.

  1. A Naturally Fluorescent Mgp Transgenic Mouse for Angiogenesis and Glaucoma Longitudinal Studies.

    Science.gov (United States)

    Asokan, Priyadarsini; Mitra, Rajendra N; Periasamy, Ramesh; Han, Zongchao; Borrás, Teresa

    2018-02-01

    Our goal was to generate and characterize a new mouse model in which only angiogenesis- and glaucoma-relevant tissues would be naturally fluorescent. The Matrix Gla (MGP) gene is highly expressed in vascular smooth muscle cells (VSMC) and trabecular meshwork (TM). We sought to direct our Mgp-Cre.KI mouse recombinase to VSMC/TM cells to produce their longitudinal fluorescent profiles. Homozygous Mgp-Cre.KI mice were crossed with Ai9 homozygous reporter mice harboring a loxP-flanked STOP cassette preventing transcription of a DsRed fluorescent protein (tdTomato). The F1 double-heterozygous (Mgp-tdTomato) was examined by direct fluorescence, whole mount, histology, and fundus photography. Custom-made filters had 554/23 emission and 609/54 exciter nanometer wavelengths. Proof of concept of the model's usefulness was conducted by inducing guided imaging laser burns. Evaluation of a vessel's leakage and proliferation was followed by noninvasive angiography. The Mgp-tdTomato mouse was viable, fertile, with normal IOP and ERG. Its phenotype exhibited red paws and snout (cartilage expression), which precluded genotyping. A fluorescent red ring was seen at the limbus and confirmed to be TM expression by histology. The entire retinal vasculature was red fluorescent (VSMC) and directly visualized by fundus photography. Laser burns on the Mgp-tdTomato allowed separation of leakiness and neovascularization evaluation parameters. The availability of a transgenic mouse naturally fluorescent in glaucoma-relevant tissues and retinal vasculature brings the unique opportunity to study a wide spectrum of single and combined glaucomatous conditions in vivo. Moreover, the Mgp-tdTomato mouse provides a new tool to study mechanisms and therapeutics of retinal angiogenesis longitudinally.

  2. A Naturally Fluorescent Mgp Transgenic Mouse for Angiogenesis and Glaucoma Longitudinal Studies

    Science.gov (United States)

    Asokan, Priyadarsini; Mitra, Rajendra N.; Periasamy, Ramesh; Han, Zongchao

    2018-01-01

    Purpose Our goal was to generate and characterize a new mouse model in which only angiogenesis- and glaucoma-relevant tissues would be naturally fluorescent. The Matrix Gla (MGP) gene is highly expressed in vascular smooth muscle cells (VSMC) and trabecular meshwork (TM). We sought to direct our Mgp-Cre.KI mouse recombinase to VSMC/TM cells to produce their longitudinal fluorescent profiles. Methods Homozygous Mgp-Cre.KI mice were crossed with Ai9 homozygous reporter mice harboring a loxP-flanked STOP cassette preventing transcription of a DsRed fluorescent protein (tdTomato). The F1 double-heterozygous (Mgp-tdTomato) was examined by direct fluorescence, whole mount, histology, and fundus photography. Custom-made filters had 554/23 emission and 609/54 exciter nanometer wavelengths. Proof of concept of the model's usefulness was conducted by inducing guided imaging laser burns. Evaluation of a vessel's leakage and proliferation was followed by noninvasive angiography. Results The Mgp-tdTomato mouse was viable, fertile, with normal IOP and ERG. Its phenotype exhibited red paws and snout (cartilage expression), which precluded genotyping. A fluorescent red ring was seen at the limbus and confirmed to be TM expression by histology. The entire retinal vasculature was red fluorescent (VSMC) and directly visualized by fundus photography. Laser burns on the Mgp-tdTomato allowed separation of leakiness and neovascularization evaluation parameters. Conclusions The availability of a transgenic mouse naturally fluorescent in glaucoma-relevant tissues and retinal vasculature brings the unique opportunity to study a wide spectrum of single and combined glaucomatous conditions in vivo. Moreover, the Mgp-tdTomato mouse provides a new tool to study mechanisms and therapeutics of retinal angiogenesis longitudinally. PMID:29392320

  3. Retinal neuroprotection by hypoxic preconditioning is independent of hypoxia-inducible factor-1 alpha expression in photoreceptors.

    Science.gov (United States)

    Thiersch, Markus; Lange, Christina; Joly, Sandrine; Heynen, Severin; Le, Yun Zheng; Samardzija, Marijana; Grimm, Christian

    2009-06-01

    Hypoxic preconditioning stabilizes hypoxia-inducible factor (HIF) 1 alpha in the retina and protects photoreceptors against light-induced cell death. HIF-1 alpha is one of the major transcription factors responding to low oxygen tension and can differentially regulate a large number of target genes. To analyse whether photoreceptor-specific expression of HIF-1 alpha is essential to protect photoreceptors by hypoxic preconditioning, we knocked down expression of HIF-1 alpha specifically in photoreceptor cells, using the cyclization recombinase (Cre)-lox system. The Cre-mediated knockdown caused a 20-fold reduced expression of Hif-1 alpha in the photoreceptor cell layer. In the total retina, RNA expression was reduced by 65%, and hypoxic preconditioning led to only a small increase in HIF-1 alpha protein levels. Accordingly, HIF-1 target gene expression after hypoxia was significantly diminished. Retinas of Hif-1 alpha knockdown animals did not show any pathological alterations, and tolerated hypoxic exposure in a comparable way to wild-type retinas. Importantly, the strong neuroprotective effect of hypoxic preconditioning against light-induced photoreceptor degeneration persisted in knockdown mice, suggesting that hypoxia-mediated survival of light exposure does not depend on an autocrine action of HIF-1 alpha in photoreceptor cells. Hypoxia-mediated stabilization of HIF-2 alpha and phosphorylation of signal transducer and activator of transcription 3 (STAT 3) were not affected in the retinas of Hif-1 alpha knockdown mice. Thus, these factors are candidates for regulating the resistance of photoreceptors to light damage after hypoxic preconditioning, along with several potentially neuroprotective genes that were similarly induced in hypoxic knockdown and control mice.

  4. Inducible knockdown of pregnancy-associated plasma protein-A gene expression in adult female mice extends life span.

    Science.gov (United States)

    Bale, Laurie K; West, Sally A; Conover, Cheryl A

    2017-08-01

    Pregnancy-associated plasma protein-A (PAPP-A) knockout (KO) mice, generated through homologous recombination in embryonic stem cells, have a significantly increased lifespan compared to wild-type littermates. However, it is unknown whether this longevity advantage would pertain to PAPP-A gene deletion in adult animals. In the present study, we used tamoxifen (Tam)-inducible Cre recombinase-mediated excision of the floxed PAPP-A (fPAPP-A) gene in mice at 5 months of age. fPAPP-A mice, which were either positive (pos) or negative (neg) for Tam-Cre, received Tam treatment with quarterly boosters. Only female mice could be used with this experimental design. fPAPP-A/neg and fPAPP-A/pos mice had similar weights at the start of the experiment and showed equivalent weight gain. We found that fPAPP-A/pos mice had a significant extension of life span (P = 0.005). The median life span was increased by 21% for fPAPP-A/pos compared to fPAPP-A/neg mice. Analysis of mortality in life span quartiles indicated that the proportion of deaths of fPAPP-A/pos mice were lower than fPAPP-A/neg mice at young adult ages (P = 0.002 for 601-800 days) and higher than fPAPP-A/neg mice at older ages (P = 0.004 for >1000 days). Thus, survival curves and age-specific mortality indicate that female mice with knockdown of PAPP-A gene expression as adults have an extended healthy life span. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  5. Rapid diagnostic detection of plum pox virus in Prunus plants by isothermal AmplifyRP(®) using reverse transcription-recombinase polymerase amplification.

    Science.gov (United States)

    Zhang, Shulu; Ravelonandro, Michel; Russell, Paul; McOwen, Nathan; Briard, Pascal; Bohannon, Seven; Vrient, Albert

    2014-10-01

    Plum pox virus (PPV) causes the most destructive viral disease known as plum pox or Sharka disease in stone fruit trees. As an important regulated pathogen, detection of PPV is thus of critical importance to quarantine and eradication of the spreading disease. In this study, the innovative development of two AmplifyRP(®) tests is reported for a rapid isothermal detection of PPV using reverse transcription-recombinase polymerase amplification. In an AmplifyRP(®) test, all specific recombination and amplification reactions occur at a constant temperature without thermal cycling and the test results are either recorded in real-time with a portable fluorescence reader or displayed using a lateral flow strip contained inside an amplicon detection chamber. The major improvement of this assay is that the entire test from sample preparation to result can be completed in as little as 20min and can be performed easily both in laboratories and in the field. The results from this study demonstrated the ability of the AmplifyRP(®) technique to detect all nine PPV strains (An, C, CR, D, EA, M, Rec, T, or W). Among the economic benefits to pathogen surveys is the higher sensitivity of the AmplifyRP(®) to detect PPV when compared to the conventional ELISA and ImmunoStrip(®) assays. This is the first report describing the use of such an innovative technique to detect rapidly plant viruses affecting perennial crops. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Recombinase polymerase amplification (RPA) combined with lateral flow (LF) strip for detection of Toxoplasma gondii in the environment.

    Science.gov (United States)

    Wu, Y D; Xu, M J; Wang, Q Q; Zhou, C X; Wang, M; Zhu, X Q; Zhou, D H

    2017-08-30

    Toxoplasma gondii infects all warm-blooded vertebrates, resulting in a great threat to human health and significant economic loss to the livestock industry. Ingestion of infectious oocysts of T. gondii from the environment is the major source of transmission. Detection of T. gondii oocysts by existing methods is laborious, time-consuming and expensive. The objective of the present study was to develop a recombinase polymerase amplification (RPA) method combined with a lateral flow (LF) strip for detection of T. gondii oocysts in the soil and water. The DNA of T. gondii oocysts was amplified by a pair of specific primers based on the T. gondii B1 gene over 15min at a constant temperature ranging from 30°C to 45°C using RPA. The amplification product was visualized by the lateral flow (LF) strip within 5min using the specific probe added to the RPA reaction system. The sensitivity of the established assay was 10 times higher than that of nested PCR with a lower detection limit of 0.1 oocyst per reaction, and there was no cross-reactivity with other closely related protozoan species. Fifty environmental samples were further assessed for the detection validity of the LF-RPA assay (B1-LF-RPA) and compared with nested PCR based on the B1 gene sequence. The B1-LF-RPA and nested PCR both showed that 5 out of the 50 environmental samples were positive. The B1-LF-RPA method was also proven to be sufficiently tolerant of existing inhibitors in the environment. In addition, the advantages of simple operation, speediness and cost-effectiveness make B1-LF-RPA a promising molecular detection tool for T. gondii. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Information filtering based on corrected redundancy-eliminating mass diffusion.

    Directory of Open Access Journals (Sweden)

    Xuzhen Zhu

    Full Text Available Methods used in information filtering and recommendation often rely on quantifying the similarity between objects or users. The used similarity metrics often suffer from similarity redundancies arising from correlations between objects' attributes. Based on an unweighted undirected object-user bipartite network, we propose a Corrected Redundancy-Eliminating similarity index (CRE which is based on a spreading process on the network. Extensive experiments on three benchmark data sets-Movilens, Netflix and Amazon-show that when used in recommendation, the CRE yields significant improvements in terms of recommendation accuracy and diversity. A detailed analysis is presented to unveil the origins of the observed differences between the CRE and mainstream similarity indices.

  8. Factors predicting emotional cue-responding behaviors of nurses in Taiwan: An observational study.

    Science.gov (United States)

    Lin, Mei-Feng; Lee, An-Yu; Chou, Cheng-Chen; Liu, Tien-Yu; Tang, Chia-Chun

    2017-10-01

    Responding to emotional cues is an essential element of therapeutic communication. The purpose of this study is to examine nurses' competence of responding to emotional cues (CRE) and related factors while interacting with standardized patients with cancer. This is an exploratory and predictive correlational study. A convenience sample of registered nurses who have passed the probationary period in southern Taiwan was recruited to participate in 15-minute videotaped interviews with standardized patients. The Medical Interview Aural Rating Scale was used to describe standardized patients' emotional cues and to measure nurses' CRE. The State-Trait Anxiety Inventory was used to evaluate nurses' anxiety level before the conversation. We used descriptive statistics to describe the data and stepwise regression to examine the predictors of nurses' CRE. A total of 110 nurses participated in the study. Regardless of the emotional cue level, participants predominately responded to cues with inappropriate distancing strategies. Prior formal communication training, practice unit, length of nursing practice, and educational level together explain 36.3% variances of the nurses' CRE. This study is the first to explore factors related to Taiwanese nurses' CRE. Compared to nurses in other countries, Taiwanese nurses tended to respond to patients' emotional cues with more inappropriate strategies. We also identified significant predictors of CRE that show the importance of communication training. Future research and education programs are needed to enhance nurses' CRE and to advocate for emotion-focused communication. Copyright © 2016 John Wiley & Sons, Ltd.

  9. A construct with fluorescent indicators for conditional expression of miRNA

    Directory of Open Access Journals (Sweden)

    Xia Xugang

    2008-10-01

    Full Text Available Abstract Background Transgenic RNAi holds promise as a simple, low-cost, and fast method for reverse genetics in mammals. It may be particularly useful for producing animal models for hypomorphic gene function. Inducible RNAi that permits spatially and temporally controllable gene silencing in vivo will enhance the power of transgenic RNAi approach. Furthermore, because microRNA (miRNA targeting specific genes can be expressed simultaneously with protein coding genes, incorporation of fluorescent marker proteins can simplify the screening and analysis of transgenic RNAi animals. Results We sought to optimally express a miRNA simultaneously with a fluorescent marker. We compared two construct designs. One expressed a red fluorescent protein (RFP and a miRNA placed in its 3' untranslated region (UTR. The other expressed the same RFP and miRNA, but the precursor miRNA (pre-miRNA coding sequence was placed in an intron that was inserted into the 3'-UTR. We found that the two constructs expressed comparable levels of miRNA. However, the intron-containing construct expressed a significantly higher level of RFP than the intron-less construct. Further experiments indicate that the 3'-UTR intron enhances RFP expression by its intrinsic gene-expression-enhancing activity and by eliminating the inhibitory effect of the pre-miRNA on the expression of RFP. Based on these findings, we incorporated the intron-embedded pre-miRNA design into a conditional expression construct that employed the Cre-loxP system. This construct initially expressed EGFP gene, which was flanked by loxP sites. After exposure to Cre recombinase, the transgene stopped EGFP expression and began expression of RFP and a miRNA, which silenced the expression of specific cellular genes. Conclusion We have designed and tested a conditional miRNA-expression construct and showed that this construct expresses both the marker genes strongly and can silence the target gene efficiently upon Cre

  10. Cartilage-Specific and Cre-Dependent Nkx3.2 Overexpression In Vivo Causes Skeletal Dwarfism by Delaying Cartilage Hypertrophy.

    Science.gov (United States)

    Jeong, Da-Un; Choi, Je-Yong; Kim, Dae-Won

    2017-01-01

    Nkx3.2, the vertebrate homologue of Drosophila bagpipe, has been implicated as playing a role in chondrogenic differentiation. In brief, Nkx3.2 is initially expressed in chondrocyte precursor cells and later during cartilage maturation, its expression is diminished in hypertrophic chondrocytes. In addition to Nkx3.2 expression analyses, previous studies using ex vivo chick embryo cultures and in vitro cell cultures have suggested that Nkx3.2 can suppress chondrocyte hypertrophy. However, it has never been demonstrated that Nkx3.2 functions in regulating chondrocyte hypertrophy during cartilage development in vivo. Here, we show that cartilage-specific and Cre-dependent Nkx3.2 overexpression in mice results in significant postnatal dwarfism in endochondral skeletons, while intramembranous bones remain unaltered. Further, we observed significant delays in cartilage hypertrophy in conditional transgenic ciTg-Nkx3.2 mice. Together, these findings confirm that Nkx3.2 is capable of controlling hypertrophic maturation of cartilage in vivo, and this regulation plays a significant role in endochondral ossification and longitudinal bone growth. J. Cell. Physiol. 232: 78-90, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Decision from the Commission of Electricity Regulation (CRE) dated from May 2, 2002 about a dispute between the manager of the power transportation network (RTE) and the autonomous administration of Parisian transports (RATP) relative to the conditions of consideration of the multiplicity of power supply points in the contractual system of access to the power grid; Decision de la Commission de Regulation de l'Electricite (CRE) en date du 2 mai 2002 sur un different qui oppose le gestionnaire du Reseau de Transport d'Electricite (RTE) et la Regie Autonome des Transports Parisiens (RATP) relatif aux conditions de prise en compte de la multiplicite des points de livraison dans le dispositif contractuel d'acces au reseau electrique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-05-01

    This document is the analysis made by the French commission of electricity regulation (CRE) about a dispute between the French manager of the power transportation grid (RTE) and the autonomous administration of Parisian transports (RATP) about its contract of access to the grid for the power supply of the underground railway of Paris. The RATP requested a regrouping of all its 7 supply points in a single contract. After analysis of the hearings, the CRE considers that no discrimination exists in the contractual system proposed by the RTE and thus the RATP request has been rejected. (J.S.)

  12. A centrifugal direct recombinase polymerase amplification (direct-RPA) microdevice for multiplex and real-time identification of food poisoning bacteria.

    Science.gov (United States)

    Choi, Goro; Jung, Jae Hwan; Park, Byung Hyun; Oh, Seung Jun; Seo, Ji Hyun; Choi, Jong Seob; Kim, Do Hyun; Seo, Tae Seok

    2016-06-21

    In this study, we developed a centrifugal direct recombinase polymerase amplification (direct-RPA) microdevice for multiplex and real-time identification of food poisoning bacteria contaminated milk samples. The microdevice was designed to contain identical triplicate functional units and each unit has four reaction chambers, thereby making it possible to perform twelve direct-RPA reactions simultaneously. The integrated microdevice consisted of two layers: RPA reagents were injected in the top layer, while spiked milk samples with food poisoning bacteria were loaded into sample reservoirs in the bottom layer. For multiplex bacterial detection, the target gene-specific primers and probes were dried in each reaction chamber. The introduced samples and reagents could be equally aliquoted and dispensed into each reaction chamber by centrifugal force, and then the multiplex direct-RPA reaction was executed. The target genes of bacteria spiked in milk could be amplified at 39 °C without a DNA extraction step by using the direct-RPA cocktails, which were a combination of a direct PCR buffer and RPA enzymes. As the target gene amplification proceeded, the increased fluorescence signals coming from the reaction chambers were recorded in real-time at an interval of 2 min. The entire process, including the sample distribution, the direct-RPA reaction, and the real-time analysis, was accomplished with a custom-made portable genetic analyzer and a miniaturized optical detector. Monoplex, duplex, and triplex food poisoning bacteria (Salmonella enterica, Escherichia coli O157:H7, and Vibrio parahaemolyticus) detection was successfully performed with a detection sensitivity of 4 cells per 3.2 μL of milk samples within 30 min. By implementing the direct-PRA on the miniaturized centrifugal microsystem, the on-site food poisoning bacteria analysis would be feasible with high speed, sensitivity, and multiplicity.

  13. Histone deacetylase 3 depletion in osteo/chondroprogenitor cells decreases bone density and increases marrow fat.

    Directory of Open Access Journals (Sweden)

    David F Razidlo

    2010-07-01

    Full Text Available Histone deacetylase (Hdac3 is a nuclear enzyme that contributes to epigenetic programming and is required for embryonic development. To determine the role of Hdac3 in bone formation, we crossed mice harboring loxP sites around exon 7 of Hdac3 with mice expressing Cre recombinase under the control of the osterix promoter. The resulting Hdac3 conditional knockout (CKO mice were runted and had severe deficits in intramembranous and endochondral bone formation. Calvarial bones were significantly thinner and trabecular bone volume in the distal femur was decreased 75% in the Hdac3 CKO mice due to a substantial reduction in trabecular number. Hdac3-CKO mice had fewer osteoblasts and more bone marrow adipocytes as a proportion of tissue area than their wildtype or heterozygous littermates. Bone formation rates were depressed in both the cortical and trabecular regions of Hdac3 CKO femurs. Microarray analyses revealed that numerous developmental signaling pathways were affected by Hdac3-deficiency. Thus, Hdac3 depletion in osterix-expressing progenitor cells interferes with bone formation and promotes bone marrow adipocyte differentiation. These results demonstrate that Hdac3 inhibition is detrimental to skeletal health.

  14. Hematopoietic Overexpression of FOG1 Does Not Affect B-Cells but Reduces the Number of Circulating Eosinophils

    Science.gov (United States)

    Du Roure, Camille; Versavel, Aude; Doll, Thierry; Cao, Chun; Pillonel, Vincent; Matthias, Gabriele; Kaller, Markus; Spetz, Jean-François; Kopp, Patrick; Kohler, Hubertus; Müller, Matthias; Matthias, Patrick

    2014-01-01

    We have identified expression of the gene encoding the transcriptional coactivator FOG-1 (Friend of GATA-1; Zfpm1, Zinc finger protein multitype 1) in B lymphocytes. We found that FOG-1 expression is directly or indirectly dependent on the B cell-specific coactivator OBF-1 and that it is modulated during B cell development: expression is observed in early but not in late stages of B cell development. To directly test in vivo the role of FOG-1 in B lymphocytes, we developed a novel embryonic stem cell recombination system. For this, we combined homologous recombination with the FLP recombinase activity to rapidly generate embryonic stem cell lines carrying a Cre-inducible transgene at the Rosa26 locus. Using this system, we successfully generated transgenic mice where FOG-1 is conditionally overexpressed in mature B-cells or in the entire hematopoietic system. While overexpression of FOG-1 in B cells did not significantly affect B cell development or function, we found that enforced expression of FOG-1 throughout all hematopoietic lineages led to a reduction in the number of circulating eosinophils, confirming and extending to mammals the known function of FOG-1 in this lineage. PMID:24747299

  15. Ptpn11 Deletion in CD4+ Cells Does Not Affect T Cell Development and Functions but Causes Cartilage Tumors in a T Cell-Independent Manner.

    Science.gov (United States)

    Miah, S M Shahjahan; Jayasuriya, Chathuraka T; Salter, Alexander I; Reilly, Emma C; Fugere, Céline; Yang, Wentian; Chen, Qian; Brossay, Laurent

    2017-01-01

    The ubiquitously expressed tyrosine phosphatase Src homology region 2 domain-containing phosphatase-2 (SHP-2, encoded by Ptpn11 ) is required for constitutive cellular processes including proliferation, differentiation, and the regulation of immune responses. During development and maturation, subsets of T cells express a variety of inhibitory receptors known to associate with phosphatases, which in turn, dephosphorylate key players of activating receptor signaling pathways. We hypothesized that SHP-2 deletion would have major effects on T cell development by altering the thresholds for activation, as well as positive and negative selection. Surprisingly, using mice conditionally deficient for SHP-2 in the T cell lineage, we show that the development of these lymphocytes is globally intact. In addition, our data demonstrate that SHP-2 absence does not compromise T cell effector functions, suggesting that SHP-2 is dispensable in these cells. Unexpectedly, in aging mice, Ptpn11 gene deletion driven by CD4 Cre recombinase leads to cartilage tumors in wrist bones in a T cell-independent manner. These tumors resemble miniature cartilaginous growth plates and contain CD4-lineage positive chondrocyte-like cells. Altogether these results indicate that SHP-2 is a cartilage tumor suppressor during aging.

  16. Decision from the Commission of Electricity Regulation (CRE) dated from June 27, 2002 about a disagreement between Semmaris company and Electricite de France, as manager of the public power distribution grid, relative to the conditions of consideration of the multiplicity of delivery points in the contractual system of access to the grid; Decision de la Commission de Regulation de l'Electricite (CRE) en date du 27 juin 2002 sur un different, qui oppose la societe Semmaris a Electricite de France, en tant que gestionnaire du reseau public de distribution d'electricite, relatif aux conditions de prise en compte de la multiplicite des points de livraison dans le dispositif contractuel d'acces au reseau electrique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-06-01

    This document presents the analysis made by the French commission of electricity regulation (CRE) about a disagreement between Semmaris company (Rungis, France) and Electricite de France (EdF) concerning the request by Semmaris for the subscription of a single contract of access to the grid for its 18 supply points instead of 9 contracts as proposed by EdF after acceptation of a partial regrouping of some supply points under the same contracts. After examination of the hearings, the CRE requested EdF to establish non-discriminatory objective criteria for the regrouping of different delivery points in a same contract before making a new examination of the disagreement between Semmaris and EdF. (J.S.)

  17. Mouse survival motor neuron alleles that mimic SMN2 splicing and are inducible rescue embryonic lethality early in development but not late.

    Directory of Open Access Journals (Sweden)

    Suzan M Hammond

    Full Text Available Spinal muscular atrophy (SMA is caused by low survival motor neuron (SMN levels and patients represent a clinical spectrum due primarily to varying copies of the survival motor neuron-2 (SMN2 gene. Patient and animals studies show that disease severity is abrogated as SMN levels increase. Since therapies currently being pursued target the induction of SMN, it will be important to understand the dosage, timing and cellular requirements of SMN for disease etiology and potential therapeutic intervention. This requires new mouse models that can induce SMN temporally and/or spatially. Here we describe the generation of two hypomorphic Smn alleles, Smn(C-T-Neo and Smn(2B-Neo. These alleles mimic SMN2 exon 7 splicing, titre Smn levels and are inducible. They were specifically designed so that up to three independent lines of mice could be generated, herein we describe two. In a homozygous state each allele results in embryonic lethality. Analysis of these mutants indicates that greater than 5% of Smn protein is required for normal development. The severe hypomorphic nature of these alleles is caused by inclusion of a loxP-flanked neomycin gene selection cassette in Smn intron 7, which can be removed with Cre recombinase. In vitro and in vivo experiments demonstrate these as inducible Smn alleles. When combined with an inducible Cre mouse, embryonic lethality caused by low Smn levels can be rescued early in gestation but not late. This provides direct genetic evidence that a therapeutic window for SMN inductive therapies may exist. Importantly, these lines fill a void for inducible Smn alleles. They also provide a base from which to generate a large repertoire of SMA models of varying disease severities when combined with other Smn alleles or SMN2-containing mice.

  18. Thyroid Hormone Signaling in Male Mouse Skeletal Muscle Is Largely Independent of D2 in Myocytes

    Science.gov (United States)

    Werneck-de-Castro, Joao P.; Fonseca, Tatiana L.; Ignacio, Daniele L.; Fernandes, Gustavo W.; Andrade-Feraud, Cristina M.; Lartey, Lattoya J.; Ribeiro, Marcelo B.; Ribeiro, Miriam O.; Gereben, Balazs

    2015-01-01

    The type 2 deiodinase (D2) activates the prohormone T4 to T3. D2 is expressed in skeletal muscle (SKM), and its global inactivation (GLOB-D2KO mice) reportedly leads to skeletal muscle hypothyroidism and impaired differentiation. Here floxed Dio2 mice were crossed with mice expressing Cre-recombinase under the myosin light chain 1f (cre-MLC) to disrupt D2 expression in the late developmental stages of skeletal myocytes (SKM-D2KO). This led to a loss of approximately 50% in D2 activity in neonatal and adult SKM-D2KO skeletal muscle and about 75% in isolated SKM-D2KO myocytes. To test the impact of Dio2 disruption, we measured soleus T3 content and found it to be normal. We also looked at the expression of T3-responsive genes in skeletal muscle, ie, myosin heavy chain I, α-actin, myosin light chain, tropomyosin, and serca 1 and 2, which was preserved in neonatal SKM-D2KO hindlimb muscles, at a time that coincides with a peak of D2 activity in control animals. In adult soleus the baseline level of D2 activity was about 6-fold lower, and in the SKM-D2KO soleus, the expression of only one of five T3-responsive genes was reduced. Despite this, adult SKM-D2KO animals performed indistinguishably from controls on a treadmill test, running for approximately 16 minutes and reached a speed of about 23 m/min; muscle strength was about 0.3 mN/m·g body weight in SKM-D2KO and control ankle muscles. In conclusion, there are multiple sources of D2 in the mouse SKM, and its role is limited in postnatal skeletal muscle fibers. PMID:26214036

  19. Bidirectional Control of Anxiety-Related Behaviors in Mice: Role of Inputs Arising from the Ventral Hippocampus to the Lateral Septum and Medial Prefrontal Cortex.

    Science.gov (United States)

    Parfitt, Gustavo Morrone; Nguyen, Robin; Bang, Jee Yoon; Aqrabawi, Afif J; Tran, Matthew M; Seo, D Kanghoon; Richards, Blake A; Kim, Jun Chul

    2017-07-01

    Anxiety is an adaptive response to potentially threatening situations. Exaggerated and uncontrolled anxiety responses become maladaptive and lead to anxiety disorders. Anxiety is shaped by a network of forebrain structures, including the hippocampus, septum, and prefrontal cortex. In particular, neural inputs arising from the ventral hippocampus (vHPC) to the lateral septum (LS) and medial prefrontal cortex (mPFC) are thought to serve as principal components of the anxiety circuit. However, the role of vHPC-to-LS and vHPC-to-mPFC signals in anxiety is unclear, as no study has directly compared their behavioral contribution at circuit level. We targeted LS-projecting vHPC cells and mPFC-projecting vHPC cells by injecting the retrogradely propagating canine adenovirus encoding Cre recombinase into the LS or mPFC, and injecting a Cre-responsive AAV (AAV8-hSyn-FLEX-hM3D or hM4D) into the vHPC. Consequences of manipulating these neurons were examined in well-established tests of anxiety. Chemogenetic manipulation of LS-projecting vHPC cells led to bidirectional changes in anxiety: activation of LS-projecting vHPC cells decreased anxiety whereas inhibition of these cells produced opposite anxiety-promoting effects. The observed anxiety-reducing function of LS-projecting cells was in contrast with the function of mPFC-projecting cells, which promoted anxiety. In addition, double retrograde tracing demonstrated that LS- and mPFC-projecting cells represent two largely anatomically distinct cell groups. Altogether, our findings suggest that the vHPC houses discrete populations of cells that either promote or suppress anxiety through differences in their projection targets. Disruption of the intricate balance in the activity of these two neuron populations may drive inappropriate behavioral responses seen in anxiety disorders.

  20. Adipose tissue (P)RR regulates insulin sensitivity, fat mass and body weight.

    Science.gov (United States)

    Shamansurova, Zulaykho; Tan, Paul; Ahmed, Basma; Pepin, Emilie; Seda, Ondrej; Lavoie, Julie L

    2016-10-01

    We previously demonstrated that the handle-region peptide, a prorenin/renin receptor [(P)RR] blocker, reduces body weight and fat mass and may improve insulin sensitivity in high-fat fed mice. We hypothesized that knocking out the adipose tissue (P)RR gene would prevent weight gain and insulin resistance. An adipose tissue-specific (P)RR knockout (KO) mouse was created by Cre-loxP technology using AP2-Cre recombinase mice. Because the (P)RR gene is located on the X chromosome, hemizygous males were complete KO and had a more pronounced phenotype on a normal diet (ND) diet compared to heterozygous KO females. Therefore, we challenged the female mice with a high-fat diet (HFD) to uncover certain phenotypes. Mice were maintained on either diet for 9 weeks. KO mice had lower body weights compared to wild-types (WT). Only hemizygous male KO mice presented with lower total fat mass, higher total lean mass as well as smaller adipocytes compared to WT mice. Although food intake was similar between genotypes, locomotor activity during the active period was increased in both male and female KO mice. Interestingly, only male KO mice had increased O2 consumption and CO2 production during the entire 24-hour period, suggesting an increased basal metabolic rate. Although glycemia during a glucose tolerance test was similar, KO males as well as HFD-fed females had lower plasma insulin and C-peptide levels compared to WT mice, suggesting improved insulin sensitivity. Remarkably, all KO animals exhibited higher circulating adiponectin levels, suggesting that this phenotype can occur even in the absence of a significant reduction in adipose tissue weight, as observed in females and, thus, may be a specific effect related to the (P)RR. (P)RR may be an important therapeutic target for the treatment of obesity and its associated complications such as type 2 diabetes.