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Sample records for acireductone dioxygenase isoforms

  1. Metal-Dependent Function of a Mammalian Acireductone Dioxygenase.

    Science.gov (United States)

    Deshpande, Aditi R; Wagenpfeil, Karina; Pochapsky, Thomas C; Petsko, Gregory A; Ringe, Dagmar

    2016-03-01

    The two acireductone dioxygenase (ARD) isozymes from the methionine salvage pathway of Klebsiella oxytoca are the only known pair of naturally occurring metalloenzymes with distinct chemical and physical properties determined solely by the identity of the divalent transition metal ion (Fe(2+) or Ni(2+)) in the active site. We now show that this dual chemistry can also occur in mammals. ARD from Mus musculus (MmARD) was studied to relate the metal ion identity and three-dimensional structure to enzyme function. The iron-containing isozyme catalyzes the cleavage of 1,2-dihydroxy-3-keto-5-(thiomethyl)pent-1-ene (acireductone) by O2 to formate and the ketoacid precursor of methionine, which is the penultimate step in methionine salvage. The nickel-bound form of ARD catalyzes an off-pathway reaction resulting in formate, carbon monoxide (CO), and 3-(thiomethyl) propionate. Recombinant MmARD was expressed and purified to obtain a homogeneous enzyme with a single transition metal ion bound. The Fe(2+)-bound protein, which shows about 10-fold higher activity than that of others, catalyzes on-pathway chemistry, whereas the Ni(2+), Co(2+), or Mn(2+) forms exhibit off-pathway chemistry, as has been seen with ARD from Klebsiella. Thermal stability of the isozymes is strongly affected by the metal ion identity, with Ni(2+)-bound MmARD being the most stable, followed by Co(2+) and Fe(2+), and Mn(2+)-bound ARD being the least stable. Ni(2+)- and Co(2+)-bound MmARD were crystallized, and the structures of the two proteins found to be similar. Enzyme-ligand complexes provide insight into substrate binding, metal coordination, and the catalytic mechanism. PMID:26858196

  2. Cerebral Microvascular Endothelial Cell Apoptosis after Ischemia: Role of Enolase-Phosphatase 1 Activation and Aci-Reductone Dioxygenase 1 Translocation.

    Science.gov (United States)

    Zhang, Yuan; Wang, Ting; Yang, Ke; Xu, Ji; Ren, Lijie; Li, Weiping; Liu, Wenlan

    2016-01-01

    Enolase-phosphatase 1 (ENOPH1), a newly discovered enzyme of the methionine salvage pathway, is emerging as an important molecule regulating stress responses. In this study, we investigated the role of ENOPH1 in blood brain barrier (BBB) injury under ischemic conditions. Focal cerebral ischemia induced ENOPH1 mRNA and protein expression in ischemic hemispheric microvessels in rats. Exposure of cultured brain microvascular endothelial cells (bEND3 cells) to oxygen-glucose deprivation (OGD) also induced ENOPH1 upregulation, which was accompanied by increased cell death and apoptosis reflected by increased 3-(4, 5-Dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide formation, lactate dehydrogenase release and TUNEL staining. Knockdown of ENOPH1 expression with siRNA or overexpressing ENOPH1 with CRISPR-activated plasmids attenuated or potentiated OGD-induced endothelial cell death, respectively. Moreover, ENOPH1 knockdown or overexpression resulted in a significant reduction or augmentation of reactive oxygen species (ROS) generation, apoptosis-associated proteins (caspase-3, PARP, Bcl-2 and Bax) and Endoplasmic reticulum (ER) stress proteins (Ire-1, Calnexin, GRP78 and PERK) in OGD-treated endothelial cells. OGD upregulated the expression of ENOPH1's downstream protein aci-reductone dioxygenase 1 (ADI1) and enhanced its interaction with ENOPH1. Interestingly, knockdown of ENOPH1 had no effect on OGD-induced ADI1 upregulation, while it potentiated OGD-induced ADI1 translocation from the nucleus to the cytoplasm. Lastly, knockdown of ENOPH1 significantly reduced OGD-induced endothelial monolayer permeability increase. In conclusion, our data demonstrate that ENOPH1 activation may contribute to OGD-induced endothelial cell death and BBB disruption through promoting ROS generation and the activation of apoptosis associated proteins, thus representing a new therapeutic target for ischemic stroke. PMID:27630541

  3. The Physcomitrella patens unique alpha-dioxygenase participates in both developmental processes and defense responses

    OpenAIRE

    Machado, Lucina; De Castro, Alexandra; Hamberg, Mats; Bannenberg, Gerard; Gaggero, Carina; Castresana, Carmen; León, Inés Ponce de

    2015-01-01

    Background Plant α-dioxygenases catalyze the incorporation of molecular oxygen into polyunsaturated fatty acids leading to the formation of oxylipins. In flowering plants, two main groups of α-DOXs have been described. While the α-DOX1 isoforms are mainly involved in defense responses against microbial infection and herbivores, the α-DOX2 isoforms are mostly related to development. To gain insight into the roles played by these enzymes during land plant evolution, we performed biochemical, ge...

  4. Molecular Dynamics Simulation of Nitrobenzene Dioxygenase Using AMBER Force Field

    OpenAIRE

    Pabis, Anna; Geronimo, Inacrist; York, Darrin M.; Paneth, Piotr

    2014-01-01

    Molecular dynamics simulation of the oxygenase component of nitrobenzene dioxygenase (NBDO) system, a member of the naphthalene family of Rieske nonheme iron dioxygenases, has been carried out using the AMBER force field combined with a new set of parameters for the description of the mononuclear nonheme iron center and iron–sulfur Rieske cluster. Simulation results provide information on the structure and dynamics of nitrobenzene dioxygenase in an aqueous environment and shed light on specif...

  5. Indoleamine 2,3-dioxygenase vaccination

    DEFF Research Database (Denmark)

    Andersen, Mads Hald; Svane, Inge Marie

    2015-01-01

    Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme. Remarkably, we discovered IDO-specific T cells that can influence adaptive immune reactions in patients with cancer. Further, a recent phase I clinical trial demonstrated long-lasting disease stabilization without toxicity in patien...... with non-small-cell lung cancer (NSCLC) who were vaccinated with an IDO-derived HLA-A2-restricted epitope....

  6. Heme-containing dioxygenases involved in tryptophan oxidation.

    Science.gov (United States)

    Millett, Elizabeth S; Efimov, Igor; Basran, Jaswir; Handa, Sandeep; Mowat, Christopher G; Raven, Emma Lloyd

    2012-04-01

    Heme iron is often used in biology for activation of oxygen. The mechanisms of oxygen activation by heme-containing monooxygenases (the cytochrome P450s) are well known, and involve formation of a Compound I species, but information on the heme-containing dioxygenase enzymes involved in tryptophan oxidation lags far behind. In this review, we gather together information emerging recently from structural, mechanistic, spectroscopic, and computational approaches on the heme dioxygenase enzymes involved in tryptophan oxidation. We explore the subtleties that differentiate various heme enzymes from each other, and use this to piece together a developing picture for oxygen activation in this particular class of heme-containing dioxygenases.

  7. The "Gln-Type" Thiol Dioxygenase from Azotobacter vinelandii is a 3-Mercaptopropionic Acid Dioxygenase.

    Science.gov (United States)

    Pierce, Brad S; Subedi, Bishnu P; Sardar, Sinjinee; Crowell, Joshua K

    2015-12-29

    Cysteine dioxygenase (CDO) is a non-heme iron enzyme that catalyzes the O2-dependent oxidation of l-cysteine to produce cysteinesulfinic acid. Bacterial CDOs have been subdivided as either "Arg-type" or "Gln-type" on the basis of the identity of conserved active site residues. To date, "Gln-type" enzymes remain largely uncharacterized. It was recently noted that the "Gln-type" enzymes are more homologous with another thiol dioxygenase [3-mercaptopropionate dioxygenase (MDO)] identified in Variovorax paradoxus, suggesting that enzymes of the "Gln-type" subclass are in fact MDOs. In this work, a putative "Gln-type" thiol dioxygenase from Azotobacter vinelandii (Av) was purified to homogeneity and characterized. Steady-state assays were performed using three substrates [3-mercaptopropionic acid (3mpa), l-cysteine (cys), and cysteamine (ca)]. Despite comparable maximal velocities, the "Gln-type" Av enzyme exhibited a specificity for 3mpa (kcat/KM = 72000 M(-1) s(-1)) nearly 2 orders of magnitude greater than those for cys (110 M(-1) s(-1)) and ca (11 M(-1) s(-1)). Supporting X-band electron paramagnetic resonance (EPR) studies were performed using nitric oxide (NO) as a surrogate for O2 binding to confirm obligate-ordered addition of substrate prior to NO. Stoichimetric addition of NO to solutions of 3mpa-bound enzyme quantitatively yields an iron-nitrosyl species (Av ES-NO) with EPR features consistent with a mononuclear (S = (3)/2) {FeNO}(7) site. Conversely, two distinct substrate-bound conformations were observed in Av ES-NO samples prepared with cys and ca, suggesting heterogeneous binding within the enzymatic active site. Analytical EPR simulations are provided to establish the relative binding affinity for each substrate (3map > cys > ca). Both kinetic and spectroscopic results presented here are consistent with 3mpa being the preferred substrate for this enzyme. PMID:26624219

  8. Hemoglobin: A Nitric-Oxide Dioxygenase

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    Paul R. Gardner

    2012-01-01

    Full Text Available Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs. Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.

  9. Structure and mechanism of mouse cysteine dioxygenase

    Science.gov (United States)

    McCoy, Jason G.; Bailey, Lucas J.; Bitto, Eduard; Bingman, Craig A.; Aceti, David J.; Fox, Brian G.; Phillips, George N.

    2006-01-01

    Cysteine dioxygenase (CDO) catalyzes the oxidation of l-cysteine to cysteine sulfinic acid. Deficiencies in this enzyme have been linked to autoimmune diseases and neurological disorders. The x-ray crystal structure of CDO from Mus musculus was solved to a nominal resolution of 1.75 Å. The sequence is 91% identical to that of a human homolog. The structure reveals that CDO adopts the typical β-barrel fold of the cupin superfamily. The NE2 atoms of His-86, -88, and -140 provide the metal binding site. The structure further revealed a covalent linkage between the side chains of Cys-93 and Tyr-157, the cysteine of which is conserved only in eukaryotic proteins. Metal analysis showed that the recombinant enzyme contained a mixture of iron, nickel, and zinc, with increased iron content associated with increased catalytic activity. Details of the predicted active site are used to present and discuss a plausible mechanism of action for the enzyme. PMID:16492780

  10. Indoleamine-2,3-dioxygenase activity in experimental human endotoxemia

    NARCIS (Netherlands)

    Padberg, Jan-Sören; Van Meurs, Matijs; Kielstein, Jan T; Martens-Lobenhoffer, Jens; Bode-Böger, Stefanie M; Zijlstra, Jan G; Kovesdy, Csaba P; Kümpers, Philipp

    2012-01-01

    UNLABELLED: BACKGROUND: Excessive tryptophan metabolism to kynurenine by the rate-limiting enzyme endothelial indoleamine 2,3-dioxygenase 1 (IDO) controls arterial vessel relaxation and causes hypotension in murine endotoxemia. However, its relevance in human endotoxemia has not been investigated so

  11. INDOLEAMINE 2,3-DIOXYGENASE (IDO AND IMMUNE TOLERANCE

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    Coma-del-Corral MJ

    2013-09-01

    Full Text Available SUMMARY: Indoleamine 2,3-dioxygenase (IDO is an intracellular and extrahepatic enzyme predominantly found in many cells, especially macrophages. Tryptophan degradation generates kynurenine, and this pathway of tryptophan metabolism is an effective mechanism for modulating the immune response. The IDO facilitates immune tolerance and is one of the main actors involved in the inhibition of cell proliferation, including activated T cells. IDO induces production of reactive oxygen species (ROS and nitric oxide (NO radicals. Several pathways involved in the regulation of immune response are regulated by redox mechanisms. Reactive oxygen and nitrogen species (ROS-RNS and other redox active molecules play key roles in immunity.

  12. Inference of Isoforms from Short Sequence Reads

    Science.gov (United States)

    Feng, Jianxing; Li, Wei; Jiang, Tao

    Due to alternative splicing events in eukaryotic species, the identification of mRNA isoforms (or splicing variants) is a difficult problem. Traditional experimental methods for this purpose are time consuming and cost ineffective. The emerging RNA-Seq technology provides a possible effective method to address this problem. Although the advantages of RNA-Seq over traditional methods in transcriptome analysis have been confirmed by many studies, the inference of isoforms from millions of short sequence reads (e.g., Illumina/Solexa reads) has remained computationally challenging. In this work, we propose a method to calculate the expression levels of isoforms and infer isoforms from short RNA-Seq reads using exon-intron boundary, transcription start site (TSS) and poly-A site (PAS) information. We first formulate the relationship among exons, isoforms, and single-end reads as a convex quadratic program, and then use an efficient algorithm (called IsoInfer) to search for isoforms. IsoInfer can calculate the expression levels of isoforms accurately if all the isoforms are known and infer novel isoforms from scratch. Our experimental tests on known mouse isoforms with both simulated expression levels and reads demonstrate that IsoInfer is able to calculate the expression levels of isoforms with an accuracy comparable to the state-of-the-art statistical method and a 60 times faster speed. Moreover, our tests on both simulated and real reads show that it achieves a good precision and sensitivity in inferring isoforms when given accurate exon-intron boundary, TSS and PAS information, especially for isoforms whose expression levels are significantly high.

  13. Expression of tryptophan 2,3-dioxygenase in mature granule cells of the adult mouse dentate gyrus

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    Ohira, Koji

    2010-09-01

    Full Text Available Abstract New granule cells are continuously generated in the dentate gyrus of the adult hippocampus. During granule cell maturation, the mechanisms that differentiate new cells not only describe the degree of cell differentiation, but also crucially regulate the progression of cell differentiation. Here, we describe a gene, tryptophan 2,3-dioxygenase (TDO, whose expression distinguishes stem cells from more differentiated cells among the granule cells of the adult mouse dentate gyrus. The use of markers for proliferation, neural progenitors, and immature and mature granule cells indicated that TDO was expressed in mature cells and in some immature cells. In mice heterozygous for the alpha-isoform of calcium/calmodulin-dependent protein kinase II, in which dentate gyrus granule cells fail to mature normally, TDO immunoreactivity was substantially downregulated in the dentate gyrus granule cells. Moreover, a 5-bromo-2'-deoxyuridine labeling experiment revealed that new neurons began to express TDO between 2 and 4 wk after the neurons were generated, when the axons and dendrites of the granule cells developed and synaptogenesis occurred. These findings indicate that TDO might be required at a late-stage of granule cell development, such as during axonal and dendritic growth, synaptogenesis and its maturation.

  14. Isolation and characterization of patatin isoforms

    NARCIS (Netherlands)

    Pots, A.M.; Gruppen, H.; Hessing, M.; Boekel, M.A.J.S. van; Voragen, A.G.J.

    1999-01-01

    Patatin has, so far, been considered a homogeneous group of proteins. A comparison of the isoforms in terms of structural properties or stability has not been reported. A method to obtain various isoform fractions as well as a comparison of the physicochemical properties of these pools is presented.

  15. Insights into the genetic diversity of initial dioxygenases from PAH-degrading bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Moser, R.; Stahl, U. [Technische Univ. Berlin, Inst. fuer Biotechnologie, Mikrobiologie und Genetik, Berlin (Germany)

    2001-07-01

    Alpha subunit genes of initial polyaromatic hydrocarbon (PAH) dioxygenases were used as targets for the PCR detection of PAH-degrading strains of the genera Pseudomonas, Comamonas and Rhodococcus which were obtained from activated sludge or soil samples. Sequence analysis of PCR products from several Pseudomonas strains showed that alpha subunits (nahAc allele) of this genus are highly conserved. PCR primers for the specific detection of alpha subunit genes of initial PAH dioxygenases from Pseudomonas strains were not suitable for detecting the corresponding genes from the genera Comamonas and Rhodococcus. Southern analysis using a heterologous gene probe derived from the P. putida OUS82 PAH dioxygenase alpha subunit identified segments of the PAH-degradation gene cluster from C. testosteroni strain H. Parts of this gene cluster containing three subunits of the initial PAH dioxygenase were isolated. These three subunits [ferredoxin (pahAb), alpha (pahAc) and beta (pahAd) subunit] were amplified by PCR as one fragment and expressed in Escherichia coli DH5{alpha}, resulting in an active initial dioxygenase with the ability to transform indole and phenanthrene. The DNA sequence alignment of alpha subunits from C. testosteroni H and various PAH-degrading bacteria permitted the design of new primers and oligonucleotide probes which are useful for the detection of the initial PAH dioxygenases from strains of Pseudomonas, Comamonas and Rhodococcus. (orig.)

  16. Overexpression of Crocus carotenoid cleavage dioxygenase, CsCCD4b, in Arabidopsis imparts tolerance to dehydration, salt and oxidative stresses by modulating ROS machinery.

    Science.gov (United States)

    Baba, Shoib Ahmad; Jain, Deepti; Abbas, Nazia; Ashraf, Nasheeman

    2015-09-15

    Apocarotenoids modulate vital physiological and developmental processes in plants. These molecules are formed by the cleavage of carotenoids, a reaction catalyzed by a family of enzymes called carotenoid cleavage dioxygenases (CCDs). Apocarotenoids like β-ionone and β-cyclocitral have been reported to act as stress signal molecules during high light stress in many plant species. In Crocus sativus, these two apocarotenoids are formed by enzymatic cleavage of β-carotene at 9, 10 and 7, 8 bonds by CsCCD4 enzymes. In the present study three isoforms of CsCCD4 were subjected to molecular modeling and docking analysis to determine their substrate specificity and all the three isoforms displayed high substrate specificity for β-carotene. Further, expression of these three CsCCD4 isoforms investigated in response to various stresses revealed that CsCCD4a and CsCCD4b exhibit enhanced expression in response to dehydration, salt and methylviologen, providing a clue towards their role in mediating plant defense response. This was confirmed by overexpressing CsCCD4b in Arabidopsis. The transgenic plants developed longer roots and possessed higher number of lateral roots. Further, overexpression of CsCCD4b imparted enhanced tolerance to salt, dehydration and oxidative stresses as was evidenced by higher survival rate, increased relative root length and biomass in transgenic plants as compared to wild type. Transgenic plants also displayed higher activity and expression of reactive oxygen species (ROS) metabolizing enzymes. This indicates that β-ionone and β-cyclocitral which are enzymatic products of CsCCD4b may act as stress signals and mediate reprogramming of stress responsive genes which ultimately leads to plant defense.

  17. Molecular evolution of bacterial indoleamine 2,3-dioxygenase.

    Science.gov (United States)

    Yuasa, Hajime J; Ushigoe, Akiko; Ball, Helen J

    2011-10-01

    Indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) are tryptophan-degrading enzymes that catalyze the first step in L-Trp catabolism via the kynurenine pathway. In mammals, TDO is mainly expressed in the liver and primarily supplies nicotinamide adenine dinucleotide (NAD(+)). TDO is widely distributed from mammals to bacteria. Active IDO enzymes have been reported only in vertebrates and fungi. In mammals, IDO activity plays a significant role in the immune system while in fungal species, IDO is constitutively expressed and supplies NAD(+), like mammalian TDO. A search of genomic databases reveals that some bacterial species also have a putative IDO gene. A phylogenetic analysis clustered bacterial IDOs into two groups, group I or group II bacterial IDOs. The catalytic efficiencies of group I bacterial IDOs were very low and they are suspected not to contribute significantly to L-Trp metabolism. The bacterial species bearing the group I bacterial IDO are scattered across a few phyla and no phylogenetically close relationship is observed between them. This suggests that the group I bacterial IDOs might be acquired by horizontal gene transmission that occurred in each lineage independently. In contrast, group II bacterial IDOs showed rather high catalytic efficiency. Particularly, the enzymatic characteristics (K(m), V(max) and inhibitor selectivity) of the Gemmatimonas aurantiaca IDO are comparable to those of mammalian IDO1, although comparison of the IDO sequences does not suggest a close evolutionary relationship. In several bacteria, TDO and the kynureninase gene (kynU) are clustered on their chromosome suggesting that these genes could be transcribed in an operon. Interestingly, G. aurantiaca has no TDO, and the IDO is clustered with kynU on its chromosome. Although the G. aurantiaca also has NadA and NadB to synthesize a quinolinic acid (a precursor of NAD(+)) via the aspartate pathway, the high activity of the G. aurantiaca IDO flanking

  18. Functional studies of sodium pump isoforms

    DEFF Research Database (Denmark)

    Clausen, Michael Jakob

    unique expression profiles and specialized functional features. We use a Two Electrode Voltage Clamp setup to determine pre-steady-state and steady-state characteristics of each isoform and design chimeras to pin-point the structural elements responsible for observed differences. With this strategy we...... and glial cells express multiple isoforms of the Na+,K+-ATPase that are sorted to different specialized subcellular compartments. We are setting up a novel assay to study the details of Na+,K+-ATPase trafficking in polarized cells. With SNAP and CLIP tagged Na+,K+-ATPase isoforms we can track newly...

  19. Conversion of 3-chlorocatechol by various catechol 2,3-dioxygenases and sequence analysis of the chlorocatechol dioxygenase region of Pseudomonas putida GJ31

    NARCIS (Netherlands)

    Mars, Astrid E.; Kingma, Jaap; Kaschabek, Stefan R.; Reineke, Walter; Janssen, Dick B.

    1999-01-01

    Pseudomonas putida GJ31 contains an unusual catechol 2,3-dioxygenase that converts 3-chlorocatechol and 3-methylcatechol, which enables the organism to use both chloroaromatics and methylaromatics for growth, A 3.1-kb region of genomic DNA of strain GJ31 containing the gene for this chlorocatechol 2

  20. Indoleamine-2,3-dioxygenase activity in experimental human endotoxemia

    Directory of Open Access Journals (Sweden)

    Padberg Jan-Sören

    2012-12-01

    Full Text Available Abstract Background Excessive tryptophan metabolism to kynurenine by the rate-limiting enzyme endothelial indoleamine 2,3-dioxygenase 1 (IDO controls arterial vessel relaxation and causes hypotension in murine endotoxemia. However, its relevance in human endotoxemia has not been investigated so far. We thus aimed to study changes in blood pressure in parallel with tryptophan and kynurenine levels during experimental endotoxemia in humans. Findings Six healthy male volunteers were given E. coli lipopolysaccharide (LPS; 4 ng/kg as a 1-min intravenous infusion. They had levels of soluble E-Selectin and soluble vascular cell adhesion molecule-1 as well as IDO activity assessed as the kynurenine-to-tryptophan plasma ratio by liquid chromatography-tandem mass spectrometry at various time points during a 24 h time course. During endotoxemia, IDO activity significantly increased, reaching peak levels at 8 h after LPS infusion (44.0 ± 15.2 vs. 29.4 ± 6.8 at baseline, P Conclusions LPS is a triggering factor for the induction of IDO in men. Our findings strongly support the concept that the induction of IDO in the vascular endothelium contributes to hypotension in human sepsis.

  1. Structure of the human 4-hydroxyphenylpyruvic acid dioxygenase gene (HPD)

    Energy Technology Data Exchange (ETDEWEB)

    Awata, H.; Endo, F.; Matsuda, I. [Kumamoto Univ. (Japan)

    1994-10-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD) is an important enzyme in tyrosine catabolism in most organisms. The activity of this enzyme is expressed mainly in the liver and developmentally regulated in mammals, and a genetic deficiency in this enzyme in humans and mice leads to hereditary tyrosinemia type 3. Using human HPD cDNA as a probe, a chromosomal gene related to HPD was isolated from human gene libraries. The human HPD gene is over 30 kb long and is split into 14 exons. The extract sizes and boundaries of exon blocks were determined, and all of the splice donor and acceptor sites conformed to the GT/AG rule. Analysis of the 5{prime} flanking sequence of the gene suggests that expression of the gene is regulated by hepatocyte-specific and liver-enriched transcription factors, as well as by hormones. These features of the 5{prime} flanking region of the gene are similar to those of other genes that are specifically expressed in hepatocytes and that are developmentally regulated. 41 refs., 2 figs., 1 tab.

  2. FSH isoform pattern in classic galactosemia

    OpenAIRE

    Gubbels, Cynthia S.; Thomas, Chris M.G.; Wodzig, Will K. W. H.; Olthaar, André J.; Jaeken, Jaak; Sweep, Fred C. G. J.; Rubio-Gozalbo, M. Estela

    2010-01-01

    Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns...

  3. Expression, purification and kinetic characterization of recombinant benzoate dioxygenase from Rhodococcus ruber UKMP-5M

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    Arezoo Tavakoli

    2016-09-01

    Full Text Available In this study, benzoate dioxygenase from Rhodococcus ruber UKMP-5M was catalyzed by oxidating the benzene ring to catechol and other derivatives. The benzoate dioxygenase (benA gene from Rhodococcus ruber UKMP-5M was then expressed, purified, characterized, The benA gene was amplified (642 bp, and the product was cloned into a pGEM-T vector.The recombinant plasmid pGEMT-benA was digested by double restriction enzymes BamHI and HindIII to construct plasmid pET28b-benA and was then ligated into Escherichia coli BL21 (DE3. The recombinant E. coli was induced with 0.5 mM isopropyl β-D-thiogalactoside (IPTG at 22˚C to produce benzoate dioxygenase. The enzyme was then purified by ion exchange chromatography after 8 purification folds. The resulting product was 25 kDa, determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE and western blotting. Benzoate dioxygenase activity was found to be 6.54 U/mL and the optimal pH and temperature were 8.5 and 25°C, respectively. Maximum velocity (Vmax and Michaelis constant (Km were 7.36 U/mL and 5.58 µM, respectively. The end metabolite from the benzoate dioxygenase reaction was cyclohexane dione, which was determined by gas chromatography mass spectrometry (GC-MS.

  4. Crystal Structure of Mammalian Cysteine dioxygenase: A Novel Mononuclear Iron Center for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Liu, Q.; Huang, Q.; Hao, Q.; Begley, T.; Karplus, P.; Stipanuk, M.

    2006-01-01

    Cysteine dioxygenase is a mononuclear iron-dependent enzyme responsible for the oxidation of cysteine with molecular oxygen to form cysteinesulfinate. This reaction commits cysteine to either catabolism to sulfate and pyruvate or to the taurine biosynthetic pathway. Cysteine dioxygenase is a member of the cupin superfamily of proteins. The crystal structure of recombinant rat cysteine dioxygenase has been determined to 1.5 Angstroms resolution, and these results confirm the canonical cupin {beta}-sandwich fold and the rare cysteinyl-tyrosine intramolecular crosslink (between Cys93 and Tyr157) seen in the recently reported murine cysteine dioxygenase structure. In contrast to the catalytically inactive mononuclear Ni(II) metallocenter present in the murine structure, crystallization of a catalytically competent preparation of rat cysteine dioxygenase revealed a novel tetrahedrally coordinated mononuclear iron center involving three histidines (His86, His88, and His140) and a water molecule. Attempts to acquire a structure with bound ligand using either co-crystallization or soaks with cysteine revealed the formation of a mixed disulfide involving Cys164 near the active site, which may explain previously observed substrate inhibition. This work provides a framework for understanding the molecular mechanisms involved in thiol dioxygenation and sets the stage for exploring the chemistry of both the novel mononuclear iron center and the catalytic role of the cysteinyl-tyrosine linkage.

  5. Substrate Oxidation by Indoleamine 2,3-Dioxygenase: EVIDENCE FOR A COMMON REACTION MECHANISM.

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    Booth, Elizabeth S; Basran, Jaswir; Lee, Michael; Handa, Sandeep; Raven, Emma L

    2015-12-25

    The kynurenine pathway is the major route of L-tryptophan (L-Trp) catabolism in biology, leading ultimately to the formation of NAD(+). The initial and rate-limiting step of the kynurenine pathway involves oxidation of L-Trp to N-formylkynurenine. This is an O2-dependent process and catalyzed by indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase. More than 60 years after these dioxygenase enzymes were first isolated (Kotake, Y., and Masayama, I. (1936) Z. Physiol. Chem. 243, 237-244), the mechanism of the reaction is not established. We examined the mechanism of substrate oxidation for a series of substituted tryptophan analogues by indoleamine 2,3-dioxygenase. We observed formation of a transient intermediate, assigned as a Compound II (ferryl) species, during oxidation of L-Trp, 1-methyl-L-Trp, and a number of other substrate analogues. The data are consistent with a common reaction mechanism for indoleamine 2,3-dioxygenase-catalyzed oxidation of tryptophan and other tryptophan analogues.

  6. PKC Isoform Expression in Modeled Microgravity

    Science.gov (United States)

    Risin, Diana; Sundaresan, Alamelu; Pellis, Neal R.; Dawson, David L. (Technical Monitor)

    1999-01-01

    Our previous studies showed that modeled (MMG) and true (USA Space Shuttle Missions STS-54 and STS-56) microgravity (MG) inhibit human lymphocyte locomotion, Modeled MG also suppressed polyclonal and antigen-specific lymphocyte activation. Activation of PKC by phorbol myristate acetate (PMA) restored the microgravity-inhibited lymphocyte locomotion as well as activation by phytohaemagglutinin (PHA), whereas calcium ionophore (ionomycin) was unable to restore these functions. Based on these results we hypothesized that MG-induced changes in lymphocyte functions are caused by a fundamental defect in signal transduction mechanism. This defect may be localized either at the PKC level or upstream of PKC, most likely, at the cell membrane level. In this study we examined the expression of PKC isoforms alpha, epsilon and delta in PBMC cultured in rotating wall vessel bioreactor, developed at NASA JSC, which models microgravity by sustaining cells in continuous free fall. The assessment of the isoforms was performed by FACS analysis following cell permeabilization. A decrease in the expression of isoforms epsilon and delta, but not isoform a, was observed in PBMC cultured in microgravity conditions. These data suggest that MMG might selectively affect the expression of Ca2+ independent isoforms of PKC Molecular analysis confirm selective suppression of Ca2+ independent isoforms of PKC.

  7. Isoform Specificity of Protein Kinase Cs in Synaptic Plasticity

    Science.gov (United States)

    Sossin, Wayne S.

    2007-01-01

    Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used "Aplysia" as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented…

  8. Crystal structure of thermostable catechol 2,3-dioxygenase determined by multiwavelength anomalous dispersion method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The selenomethionyl derivative of the thermostable catechol 2,3-dioxygenase (SeMet-TC23O) is expressed,purified and crystallized. By using multiwave length anomalous dispersion (MAD) phasing techniques, the crystal structure of TC23O at 0.3 nm resolutions is determined.TC23O is a homotetramer. Each monomer is composed of N-terminal and C-terminal domains (residues 1~153 and 153~319, respectively). The two domains are proximately symmetric by a non-crystallographic axis. Each domain contains two characteristic motifs which are found in almost all of extradial dioxygenases.Kevwords: multiwavelength anomalous dispersion (MAD), X-ray diffraction, thermostable catechol 2,3-dioxygenase, crystal structure,synchrotron light source.

  9. Crystal Structures of Fe2+ Dioxygenase Superoxo, Alkylperoxo, and Bound Product Intermediates

    OpenAIRE

    Kovaleva, Elena G.; Lipscomb, John D.

    2007-01-01

    We report the structures of three intermediates in the O2 activation and insertion reactions of an extradiol ring-cleaving dioxygenase. A crystal of Fe2+-containing homoprotocatechuate 2,3-dioxygenase was soaked in the slow substrate 4-nitrocatechol in a low O2 atmosphere. The X-ray crystal structure shows that three different intermediates reside in different subunits of a single homotetrameric enzyme molecule. One of these is the key substrate-alkylperoxo-Fe2+ intermediate, which has been p...

  10. Cloning and Characterization of a Sulfonate/α-Ketoglutarate Dioxygenase from Saccharomyces cerevisiae

    OpenAIRE

    Hogan, Deborah A.; Auchtung, Thomas A.; Hausinger, Robert P.

    1999-01-01

    The Saccharomyces cerevisiae open reading frame YLL057c is predicted to encode a gene product with 31.5% amino acid sequence identity to Escherichia coli taurine/α-ketoglutarate dioxygenase and 27% identity to Ralstonia eutropha TfdA, a herbicide-degrading enzyme. Purified recombinant yeast protein is shown to be an Fe(II)-dependent sulfonate/α-ketoglutarate dioxygenase. Although taurine is a poor substrate, a variety of other sulfonates are utilized, with the best natural substrates being is...

  11. Antiangiogenic VEGF Isoform in Inflammatory Myopathies

    Directory of Open Access Journals (Sweden)

    Nila Volpi

    2013-01-01

    Full Text Available Objective. To investigate expression of vascular endothelial growth factor (VEGF antiangiogenic isoform A-165b on human muscle in idiopathic inflammatory myopathies (IIM and to compare distribution of angiogenic/antiangiogenic VEGFs, as isoforms shifts are described in other autoimmune disorders. Subjects and Methods. We analyzed VEGF-A165b and VEGF-A by western blot and immunohistochemistry on skeletal muscle biopsies from 21 patients affected with IIM (polymyositis, dermatomyositis, and inclusion body myositis and 6 control muscle samples. TGF-β, a prominent VEGF inductor, was analogously evaluated. Intergroup differences of western blot bands density were statistically examined. Endomysial vascularization, inflammatory score, and muscle regeneration, as pathological parameters of IIM, were quantitatively determined and their levels were confronted with VEGF expression. Results. VEGF-A165b was significantly upregulated in IIM, as well as TGF-β. VEGF-A was diffusely expressed on unaffected myofibers, whereas regenerating/atrophic myofibres strongly reacted for both VEGF-A isoforms. Most inflammatory cells and endomysial vessels expressed both isoforms. VEGF-A165b levels were in positive correlation to inflammatory score, endomysial vascularization, and TGF-β. Conclusions. Our findings indicate skeletal muscle expression of antiangiogenic VEGF-A165b and preferential upregulation in IIM, suggesting that modulation of VEGF-A isoforms may occur in myositides.

  12. Ikaros isoforms:The saga continues

    Institute of Scientific and Technical Information of China (English)

    Laura; A; Perez-Casellas; Aleksandar; Savic; Sinisa; Dovat

    2011-01-01

    Through alternate splicing,the Ikaros gene produces multiple proteins.Ikaros is essential for normal hematopoiesis and possesses tumor suppressor activity.Ikaros isoforms interact to form dimers and potentially multimeric complexes.Diverse Ikaros complexes produced by the presence of different Ikaros isoforms are hypothesized to confer distinct functions.Small dominantnegative Ikaros isoforms have been shown to inhibit the tumor suppressor activity of full-length Ikaros.Here,we describe how Ikaros activity is regulated by the coordinated expression of the largest Ikaros isoforms IK-1 and IK-H.Although IK-1 is described as full-length Ikaros,IK-H is the longest Ikaros isoform.IK-H,which includes residues coded by exon 3B (60 bp that lie between exons 3 and 4),is abundant in human but not murine hematopoietic cells.Specific residues that lie within the 20 amino acids encoded by exon 3B give IK-H DNA-binding characteristics that are distinct from those of IK-1.Moreover,IK-H can potentiate or inhibit the ability of IK-1 to bind DNA.IK-H binds to the regulatory regions of genes that are upregulated by Ikaros,but not genes that are repressed by Ikaros.Although IK-1 localizes to pericentromeric heterochromatin,IK-H can be found in both pericentromeric and non-pericentromeric locations.Anti-silencing activity of gamma satellite DNA has been shown to depend on the binding of IK-H,but not other Ikaros isoforms.The unique features of IK-H,its influence on Ikaros activity,and the lack of IK-H expression in mice suggest that Ikaros function in humans may be more complex and possibly distinct from that in mice.

  13. A biological pathway linking inflammation and depression: activation of indoleamine 2,3-dioxygenase

    Directory of Open Access Journals (Sweden)

    Christmas DM

    2011-07-01

    Full Text Available David M Christmas, JP Potokar, Simon JC DaviesAcademic Unit of Psychiatry, School of Social and Community Medicine, University of Bristol, Bristol, UK A presentation relating to this manuscript was made by Dr David Christmas at the 9th International Meeting on Clinical Pharmacology in Psychiatry (9th IMCPP in Copenhagen, Denmark in September 2010Abstract: This article highlights the evidence linking depression to increased inflammatory drive and explores putative mechanisms for the association by reviewing both preclinical and clinical literature. The enzyme indoleamine 2,3-dioxygenase is induced by proinflammatory cytokines and may form a link between immune functioning and altered neurotransmission, which results in depression. Increased indoleamine 2,3-dioxygenase activity may cause both tryptophan depletion and increased neurotoxic metabolites of the kynurenine pathway, two alterations which have been hypothesized to cause depression. The tryptophan-kynurenine pathway is comprehensively described with a focus on the evidence linking metabolite alterations to depression. The use of immune-activated groups at high risk of depression have been used to explore these hypotheses; we focus on the studies involving chronic hepatitis C patients receiving interferon-alpha, an immune activating cytokine. Findings from this work have led to novel strategies for the future development of antidepressants including inhibition of indoleamine 2,3-dioxygenase, moderating the cytokines which activate it, or addressing other targets in the kynurenine pathway.Keywords: depression, inflammation, indoleamine 2,3-dioxygenase, kynurenine, serotonin, tryptophan

  14. Structures of aminophenol dioxygenase in complex with intermediate, product and inhibitor.

    Science.gov (United States)

    Li, De Feng; Zhang, Jia Yue; Hou, Yan Jie; Liu, Lei; Hu, Yonglin; Liu, Shuang Jiang; Wang, Da Cheng; Liu, Wei

    2013-01-01

    Dioxygen activation by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Here, crystal structures of 2-aminophenol 1,6-dioxygenase, an enzyme that represents a minor group of extradiol dioxygenases and that catalyses the ring opening of 2-aminophenol, in complex with the lactone intermediate (4Z,6Z)-3-iminooxepin-2(3H)-one and the product 2-aminomuconic 6-semialdehyde and in complex with the suicide inhibitor 4-nitrocatechol are reported. The Fe-ligand binding schemes observed in these structures revealed some common geometrical characteristics that are shared by the published structures of extradiol dioxygenases, suggesting that enzymes that catalyse the oxidation of noncatecholic compounds are very likely to utilize a similar strategy for dioxygen activation and the fission of aromatic rings as the canonical mechanism. The Fe-ligation arrangement, however, is strikingly enantiomeric to that of all other 2-His-1-carboxylate enzymes apart from protocatechuate 4,5-dioxygenase. This structural variance leads to the generation of an uncommon O(-)-Fe(2+)-O(-) species prior to O(2) binding, which probably forms the structural basis on which APD distinguishes its specific substrate and inhibitor, which share an analogous molecular structure.

  15. Prognostic role of indoleamine 2,3-dioxygenase in endometrial carcinoma

    NARCIS (Netherlands)

    de Jong, Renske A; Kema, Ido P; Boerma, Annemarie; Boezen, Hendrika; van der Want, Johannes J L; Gooden, Marloes J M; Hollema, Harmen; Nijman, Hans W

    2012-01-01

    Objective. Indoleamine-2,3-dioxygenase (IDO) suppresses the function of T-lymphocytes and is an important immune escape mechanism for cancer. Therefore, it is to be expected that IDO influences prognosis of cancer patients. This study aimed to investigate the prognostic role of IDO expression in a l

  16. The immune system strikes back: cellular immune responses against indoleamine 2,3-dioxygenase

    DEFF Research Database (Denmark)

    Sørensen, Rikke Baek; Berge-Hansen, Linda; Junker, Niels;

    2009-01-01

    BACKGROUND: The enzyme indoleamine 2,3-dioxygenase (IDO) exerts an well established immunosuppressive function in cancer. IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it promotes the establishment of peripheral immune toleran......, IDO-based immunotherapy holds the promise to boost anti-cancer immunotherapy in general....

  17. 4-Nitrocatechol as a colorimetric probe for non-heme iron dioxygenases.

    Science.gov (United States)

    Tyson, C A

    1975-03-10

    4-Nitrocatechol is examined as an active site probe for non-heme iron dioxygenases and found to be of value, particularly with those containing iron in the Fe(II) oxidation state. 4-Nitrocatechol is astrong competitive inhibitor of substrate oxygenation by protocatechuate 3,4-dioxygenase, forming a reversible complex with this enzyme, and by pyrocatechase. The number of binding sites per enzyme molecule titrated spectrophotometrically with 4-nitrocatechol agrees with results from previous studies with either the principal substrate or other analogues, as expected of an effective probe. Despite these facts and the observation that both enzymes cleave the same substrates at the same carbon-carbon bond, the optical and electron paramagnetic resonance (EPR) spectra of their 4-nitrocatechol complexes are remarkably different. The 4-nitocatechol-protocatechuate 3,4-dioxygenase optical spectra resemble that of the 4-nitrocatecholate ion shifted 20 to 30 nm to longer wavelength. Concomitant with this change the EPR signal centered at g equal 4.28 shows increased rhombicity (g values at 4.74, 4.28, and 3.74). In contrast, the spectrum of the 4-nitrocatechol-pyrocatechase complex has a maximum at the same wavelength as that of a 1:1 solution of free Fe(II) and 4-nitrocatechol in the absence of enzyme after titration of the catecholic protons with base and the g equal 4.28 EPR signal is not resolved at liquid N-2 temperature. These changes are interpreted as resulting in part from a pronounced change in the ligand fields about the irons at the active sites which in the case of protocatechuate 3,4-dioxygenase leads to enzyme inactivation. The results also are the first indication that substrate analogues change their ionization form upon complexation with Fe (III) dioxygenases. The interaction of the probe with metapyrocatechase, an Fe(III) containing dioxygenase, and with several additional oxygenases and hydroperoxidases is also briefly examined. The probe is not specific

  18. New isoforms of rat Aquaporin-4

    DEFF Research Database (Denmark)

    Moe, Svein Erik; Sorbo, Jan Gunnar; Søgaard, Rikke;

    2008-01-01

    an intracellular localization when expressed in cell lines and do not transport water when expressed in Xenopus oocytes. In contrast, the largest of the new isoforms, AQP4e, which contains a novel N-terminal domain, is localized at the plasma membrane in cell lines and functions as a water transporter in Xenopus...

  19. p53 isoforms change p53 paradigm

    OpenAIRE

    Bourdon, JC

    2014-01-01

    Although p53 defines cellular responses to cancer treatment it is not clear how p53 can be used to control cell fate outcome. Data demonstrate that so-called p53 does not exist as a single protein, but is in fact a group of p53 protein isoforms whose expression can be manipulated to control the cellular response to treatment.

  20. Isoforms of murine and human serum amyloid P component

    DEFF Research Database (Denmark)

    Nybo, Mads; Hackler, R; Kold, B;

    1998-01-01

    Isoelectric focusing (IEF) and immunofixation of murine serum amyloid P component (SAP), purified and in serum, showed a distinct and strain-dependent isoform pattern with up to seven bands (pI 5.1-5.7). Neuraminidase treatment caused a shift of the isoforms to more basic pI values, but did...... of isoforms of human SAP required the presence of urea and higher SAP concentrations. TEF and immunofixation of SAP monomers showed five to eight isoforms, ranging from pI 4.7-5.7. IEF of SAP in human serum resulted in a less distinct pattern and more acidic isoforms. As with murine SAP, neuraminidase...

  1. EASI—enrichment of alternatively spliced isoforms

    OpenAIRE

    Julian P Venables; Burn, John

    2006-01-01

    Alternative splicing produces more than one protein from the majority of genes and the rarer forms can have dominant functions. Instability of alternative transcripts can also hinder the study of regulation of gene expression by alternative splicing. To investigate the true extent of alternative splicing we have developed a simple method of enriching alternatively spliced isoforms (EASI) from PCRs using beads charged with Thermus aquaticus single-stranded DNA-binding protein (T.Aq ssb). This ...

  2. Differential water permeability and regulation of three aquaporin 4 isoforms

    DEFF Research Database (Denmark)

    Fenton, Robert A.; Moeller, Hanne B; Zelenina, Marina;

    2010-01-01

    Aquaporin 4 (AQP4) is expressed in the perivascular glial endfeet and is an important pathway for water during formation and resolution of brain edema. In this study, we examined the functional properties and relative unit water permeability of three functional isoforms of AQP4 expressed...... in the brain (M1, M23, Mz). The M23 isoform gave rise to square arrays when expressed in Xenopus laevis oocytes. The relative unit water permeability differed significantly between the isoforms in the order of M1 > Mz > M23. None of the three isoforms were permeable to small osmolytes nor were they affected...... by changes in external K(+) concentration. Upon protein kinase C (PKC) activation, oocytes expressing the three isoforms demonstrated rapid reduction of water permeability, which correlated with AQP4 internalization. The M23 isoform was more sensitive to PKC regulation than the longer isoforms...

  3. Discovery of Key Dioxygenases that Diverged the Paraherquonin and Acetoxydehydroaustin Pathways in Penicillium brasilianum.

    Science.gov (United States)

    Matsuda, Yudai; Iwabuchi, Taiki; Fujimoto, Takayuki; Awakawa, Takayoshi; Nakashima, Yu; Mori, Takahiro; Zhang, Huiping; Hayashi, Fumiaki; Abe, Ikuro

    2016-09-28

    Paraherquonin (1), a fungal meroterpenoid produced by Penicillium brasilianum NBRC 6234, possesses a unique, highly congested hexacyclic molecular architecture. Here we identified the biosynthetic gene cluster of 1 (the prh cluster) and elucidated the pathway up to berkeleydione (2), which serves as the key intermediate for the biosynthesis of 1 as well as many other meroterpenoids. Interestingly, the nonheme iron and α-ketoglutarate-dependent dioxygenase PrhA constructs the cycloheptadiene moiety to afford 2 from preaustinoid A1 (6), probably via the homoallyl-homoallyl radical rearrangement. Additionally, another fungal strain, P. brasilianum MG11, which produces acetoxydehydroaustin instead of 1, was found to have a gene cluster nearly identical to the prh cluster. The dioxygenase encoded by the cluster shares 92% sequence identity with PrhA, and also accepts 6 but produces preaustinoid A3 (17) with a spiro-lactone system, generating a diverging point for the two different meroterpenoid pathways in the same species.

  4. Novel carotenoid cleavage dioxygenase catalyzes the first dedicated step in saffron crocin biosynthesis

    KAUST Repository

    Frusciante, Sarah

    2014-08-05

    Crocus sativus stigmas are the source of the saffron spice and accumulate the apocarotenoids crocetin, crocins, picrocrocin, and safranal, responsible for its color, taste, and aroma. Through deep transcriptome sequencing, we identified a novel dioxygenase, carotenoid cleavage dioxygenase 2 (CCD2), expressed early during stigma development and closely related to, but distinct from, the CCD1 dioxygenase family. CCD2 is the only identified member of a novel CCD clade, presents the structural features of a bona fide CCD, and is able to cleave zeaxanthin, the presumed precursor of saffron apocarotenoids, both in Escherichia coli and in maize endosperm. The cleavage products, identified through high-resolution mass spectrometry and comigration with authentic standards, are crocetin dialdehyde and crocetin, respectively. In vitro assays show that CCD2 cleaves sequentially the 7,8 and 7′,8′ double bonds adjacent to a 3-OH-β-ionone ring and that the conversion of zeaxanthin to crocetin dialdehyde proceeds via the C30 intermediate 3-OH-β-apo-8′-carotenal. In contrast, zeaxanthin cleavage dioxygenase (ZCD), an enzyme previously claimed to mediate crocetin formation, did not cleave zeaxanthin or 3-OH-β-apo-8′-carotenal in the test systems used. Sequence comparison and structure prediction suggest that ZCD is an N-truncated CCD4 form, lacking one blade of the β-propeller structure conserved in all CCDs. These results constitute strong evidence that CCD2 catalyzes the first dedicated step in crocin biosynthesis. Similar to CCD1, CCD2 has a cytoplasmic localization, suggesting that it may cleave carotenoids localized in the chromoplast outer envelope.

  5. Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase

    OpenAIRE

    Kuehnl, Susanne; Schroecksnadel, Sebastian; Temml, Veronika; Gostner, Johanna M.; Schennach, Harald; Schuster, Daniela; Schwaiger, Stefan; Rollinger, Judith M.; Fuchs, Dietmar; Stuppner, Hermann

    2013-01-01

    Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells i...

  6. 4-Hydroxyphenylpyruvate dioxygenase inhibitors in combination with safeners: solutions for modern and sustainable agriculture.

    Science.gov (United States)

    Ahrens, Hartmut; Lange, Gudrun; Müller, Thomas; Rosinger, Chris; Willms, Lothar; van Almsick, Andreas

    2013-09-01

    Inhibitors of 4-hydroxyphenylpyruvate dioxygenase (HPPD) prevent plant carotenoid pigment formation, which in turn leads to chlorophyll degradation. This "bleaching" herbicide mode of action provides weed-control products for various crops, such as rice, corn, and cereals. Combinations with suitable safeners allow the full exploitation of the potential of this compound class to selectively control major weed problems, including rapidly increasing cases of resistance against other important herbicide classes.

  7. Indoleamine 2,3-dioxygenase expression in patients with allergic rhinitis: a case-control study

    OpenAIRE

    Luukkainen Annika; Karjalainen Jussi; Honkanen Teemu; Lehtonen Mikko; Paavonen Timo; Toppila-Salmi Sanna

    2011-01-01

    Abstract Background Indoleamine 2,3-dioxygenase (IDO) is a tryptophan catalyzing enzyme. It has been suggested that it has a role in lower airway allergic inflammations, but its role in allergic rhinitis has not been investigated. Objective Our aim was to evaluate the expression of IDO in the nasal mucosa of allergic rhinitis patients allergic to birch pollen during peak exposure to birch pollen allergen and compare it to non-atopic patients. Methods IDO expression was immunohistochemically e...

  8. Characterization of an indoleamine 2,3-dioxygenase-like protein found in humans and mice.

    Science.gov (United States)

    Ball, Helen J; Sanchez-Perez, Angeles; Weiser, Silvia; Austin, Christopher J D; Astelbauer, Florian; Miu, Jenny; McQuillan, James A; Stocker, Roland; Jermiin, Lars S; Hunt, Nicholas H

    2007-07-01

    Indoleamine 2,3-dioxygenase (INDO) and tryptophan 2,3-dioxygenase (TDO) each catalyze the first step in the kynurenine pathway of tryptophan metabolism. We describe the discovery of another enzyme with this activity, indoleamine 2,3-dioxygenase-like protein (INDOL1), which is closely related to INDO and is expressed in mice and humans. The corresponding genes have a similar genomic structure and are situated adjacent to each other on human and mouse chromosome 8. They are likely to have arisen by gene duplication before the origin of the tetrapods. The expression of INDOL1 is highest in the mouse kidney, followed by epididymis, and liver. Expression of mouse INDOL1 was further localized to the tubular cells in the kidney and the spermatozoa. INDOL1 was assigned its name because of its structural similarity to INDO. We demonstrate that INDOL1 catalyses the conversion of tryptophan to kynurenine therefore a more appropriate nomenclature for the enzymes might be INDO-1 and INDO-2, or the more commonly-used abbreviations, IDO-1 and IDO-2. Although the two proteins have similar enzymatic activities, their different expression patterns within tissues and during malaria infection, suggests a distinct role for each protein. This identification of INDOL1 may help to explain the regulation of the diversity of physiological and patho-physiological processes in which the kynurenine pathway is involved.

  9. Isolation and characterization of two novel halotolerant Catechol 2, 3-dioxygenases from a halophilic bacterial consortium

    Science.gov (United States)

    Guo, Guang; Fang, Tingting; Wang, Chongyang; Huang, Yong; Tian, Fang; Cui, Qijia; Wang, Hui

    2015-12-01

    Study of enzymes in halophiles will help to understand the mechanism of aromatic hydrocarbons degradation in saline environment. In this study, two novel catechol 2,3-dioxygenases (C23O1 and C23O2) were cloned and overexpressed from a halophilic bacterial consortium enriched from an oil-contaminated saline soil. Phylogenetic analysis indicated that the novel C23Os and their relatives formed a new branch in subfamily I.2.A of extradiol dioxygenases and the sequence differences were further analyzed by amino acid sequence alignment. Two enzymes with the halotolerant feature were active over a range of 0-30% salinity and they performed more stable at high salinity than in the absence of salt. Surface electrostatic potential and amino acids composition calculation suggested high acidic residues content, accounting for their tolerance to high salinity. Moreover, two enzymes were further characterized. The enzymes activity both increased in the presence of Fe3+, Fe2+, Cu2+ and Al3+ and showed no significant inhibition by other tested metal ions. The optimal temperatures for the C23Os were 40 °C and 60 °C and their best substrates were catechol and 4-methylcatechol respectively. As the firstly isolated and characterized catechol dioxygenases from halophiles, the two halotolerant C23Os presented novel characteristics suggesting their potential application in aromatic hydrocarbons biodegradation.

  10. Characterizations of Two Bacterial Persulfide Dioxygenases of the Metallo-β-lactamase Superfamily.

    Science.gov (United States)

    Sattler, Steven A; Wang, Xia; Lewis, Kevin M; DeHan, Preston J; Park, Chung-Min; Xin, Yufeng; Liu, Honglei; Xian, Ming; Xun, Luying; Kang, ChulHee

    2015-07-31

    Persulfide dioxygenases (PDOs), also known as sulfur dioxygenases (SDOs), oxidize glutathione persulfide (GSSH) to sulfite and GSH. PDOs belong to the metallo-β-lactamase superfamily and play critical roles in animals, plants, and microorganisms, including sulfide detoxification. The structures of two PDOs from human and Arabidopsis thaliana have been reported; however, little is known about the substrate binding and catalytic mechanism. The crystal structures of two bacterial PDOs from Pseudomonas putida and Myxococcus xanthus were determined at 1.5- and 2.5-Å resolution, respectively. The structures of both PDOs were homodimers, and their metal centers and β-lactamase folds were superimposable with those of related enzymes, especially the glyoxalases II. The PDOs share similar Fe(II) coordination and a secondary coordination sphere-based hydrogen bond network that is absent in glyoxalases II, in which the corresponding residues are involved instead in coordinating a second metal ion. The crystal structure of the complex between the Pseudomonas PDO and GSH also reveals the similarity of substrate binding between it and glyoxalases II. Further analysis implicates an identical mode of substrate binding by known PDOs. Thus, the data not only reveal the differences in metal binding and coordination between the dioxygenases and the hydrolytic enzymes in the metallo-β-lactamase superfamily, but also provide detailed information on substrate binding by PDOs. PMID:26082492

  11. Crystal structure of 2-nitropropane dioxygenase complexed with FMN and substrate. Identification of the catalytic base.

    Science.gov (United States)

    Ha, Jun Yong; Min, Ji Young; Lee, Su Kyung; Kim, Hyoun Sook; Kim, Do Jin; Kim, Kyoung Hoon; Lee, Hyung Ho; Kim, Hye Kyung; Yoon, Hye-Jin; Suh, Se Won

    2006-07-01

    Nitroalkane compounds are widely used in chemical industry and are also produced by microorganisms and plants. Some nitroalkanes have been demonstrated to be carcinogenic, and enzymatic oxidation of nitroalkanes is of considerable interest. 2-Nitropropane dioxygenases from Neurospora crassa and Williopsis mrakii (Hansenula mrakii), members of one family of the nitroalkane-oxidizing enzymes, contain FMN and FAD, respectively. The enzymatic oxidation of nitroalkanes by 2-nitropropane dioxygenase operates by an oxidase-style catalytic mechanism, which was recently shown to involve the formation of an anionic flavin semiquinone. This represents a unique case in which an anionic flavin semiquinone has been experimentally observed in the catalytic pathway for oxidation catalyzed by a flavin-dependent enzyme. Here we report the first crystal structure of 2-nitropropane dioxygenase from Pseudomonas aeruginosa in two forms: a binary complex with FMN and a ternary complex with both FMN and 2-nitropropane. The structure identifies His(152) as the proposed catalytic base, thus providing a structural framework for a better understanding of the catalytic mechanism. PMID:16682407

  12. Expression Pattern and Clinicopathological Relevance of the Indoleamine 2,3-Dioxygenase 1/Tryptophan 2,3-Dioxygenase Protein in Colorectal Cancer.

    Science.gov (United States)

    Chen, I-Chien; Lee, Kuen-Haur; Hsu, Ying-Hua; Wang, Wei-Ran; Chen, Chuan-Mu; Cheng, Ya-Wen

    2016-01-01

    Aims. Cancer cells use the indoleamine 2,3-dioxygenase 1 (IDO1) pathway to suppress the host's immune response in order to facilitate survival, growth, invasion, and metastasis of malignant cells. Higher IDO1 expression was shown to be involved in colorectal cancer (CRC) progression and to be correlated with impaired clinical outcome. However, the potential correlation between the expression of IDO1 in a CRC population with a low mutation rate of the APC gene remains unknown. Material and Methods. Tissues and blood samples were collected from 192 CRC patients. The expressions of IDO1, tryptophan 2,3-dioxygenase (TDO2), and beta-catenin proteins were analyzed by immunohistochemistry. Microsatellite instability (MSI) was determined by PCR amplification of microsatellite loci. Results. The results showed that high IDO1 or TDO2 protein expression was associated with characteristics of more aggressive phenotypes of CRC. For the first time, they also revealed a positive correlation between the abnormal expression of beta-catenin and IDO1 or TDO2 proteins in a CRC population with a low mutation rate of APC. Conclusion. We concluded that an IDO1-regulated molecular pathway led to abnormal expression of beta-catenin in the nucleus/cytoplasm of CRC patients with low mutation rate of APC, making IDO1 an interesting target for immunotherapy in CRC. PMID:27578919

  13. Tumorigenic properties of alternative osteopontin isoforms in mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Sergey V., E-mail: Sergey.Ivanov@med.nyu.edu [Thoracic Surgery Laboratory, Cardiothoracic Surgery Department, NYU Langone Medical Center, 462 First Ave., Bellevue Hospital, Room 15N20, NY 10016 (United States); Ivanova, Alla V.; Goparaju, Chandra M.V.; Chen, Yuanbin; Beck, Amanda; Pass, Harvey I. [Thoracic Surgery Laboratory, Cardiothoracic Surgery Department, NYU Langone Medical Center, 462 First Ave., Bellevue Hospital, Room 15N20, NY 10016 (United States)

    2009-05-08

    Osteopontin (SPP1) is an inflammatory cytokine that we previously characterized as a diagnostic marker in patients with asbestos-induced malignant mesothelioma (MM). While SPP1 shows both pro- and anti-tumorigenic biological effects, little is known about the molecular basis of these activities. In this study, we demonstrate that while healthy pleura possesses all three differentially spliced SPP1 isoforms (A-C), in clinical MM specimens isoform A is markedly up-regulated and predominant. To provide a clue to possible functions of the SPP1 isoforms we next performed their functional evaluation via transient expression in MM cell lines. As a result, we report that isoforms A-C demonstrate different activities in cell proliferation, wound closure, and invasion assays. These findings suggest different functions for SPP1 isoforms and underline pro-tumorigenic properties of isoforms A and B.

  14. Developmental expression of two Haliotis asinina hemocyanin isoforms.

    Science.gov (United States)

    Streit, Klaus; Jackson, Daniel; Degnan, Bernard M; Lieb, Bernhard

    2005-09-01

    Hemocyanins are large copper-containing respiratory proteins that play a role in oxygen transport in many molluscs. In some species only one hemocyanin isoform is present while in others two are expressed. The physiological relevance of these isoforms is unclear and the developmental and tissue-specific expression of hemocyanin genes is largely unknown. Here we show that two hemocyanin genes in the gastropod Haliotis asinina, which encode H. asinina hemocyanin (HaH1) and HaH2 isoforms, are developmentally expressed. These genes initially are expressed in a small number of mesenchyme cells at trochophore and pre-torsional veliger stages, with HaH1 expression slightly preceding HaH2. These cells largely are localized to the visceral mass, although a small number of cells are present in head and foot regions. Following metamorphosis the isoforms show overlapping as well as isoform-specific expression profiles, suggesting some degree of isoform-specific function.

  15. Androgen receptor isoforms in human and rat prostate

    Institute of Scientific and Technical Information of China (English)

    Shu-JieXIA; Gang-YaoHAO; Xiao-DaTANG

    2000-01-01

    Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatic tissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from patients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPH specimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were examined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In human BPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 isoforms at various combinations and 7/41(17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 isoforms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at different combinations. Binding of 3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-fold excess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms are different in different patients. Although their genesis is not clear, the therapeutic implication of the present observation appears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec;2:307-310)

  16. Mechanism of S-oxygenation by a cysteine dioxygenase model complex

    Science.gov (United States)

    Sastry, G. Narahari

    2012-01-01

    In this work we present the first computational study on a biomimetic cysteine dioxygenase model complex, [FeII(LN3S)]+ where LN3S is a tetradentate ligand with a bis(imino)pyridyl scaffold and a pendant arylthiolate group. The reaction mechanism of sulfur dioxygenation with O2 was examined by density functional theory (DFT) methods, and compared to results obtained for cysteine dioxygenase. The reaction proceeds via multistate reactivity patterns on competing singlet, triplet and quintet spin state surfaces. The reaction mechanism is analogous to that found for cysteine dioxygenase enzymes [Kumar, D.; Thiel, W.; de Visser, S. P. J. Am. Chem. Soc. 2011, 133, 3869–3882], hence the computations indicate that this complex can closely mimic the enzymatic process. The catalytic mechanism starts from an iron(III)-superoxo complex and the attack of the terminal oxygen atom of the superoxo group on the sulfur atom of the ligand. Subsequently, the dioxygen bond breaks to form an iron(IV)-oxo complex with a bound sulfenato group. After reorganization the second oxygen atom is transferred to the substrate to give a sulfinic acid product. An alternative mechanism involving the direct attack of dioxygen on the sulfur, without involving any iron-oxygen intermediates, was also examined. Importantly, a significant energetic preference for dioxygen coordinating to the iron center prior to attack at sulfur was discovered and serves to elucidate the function of the metal ion in the reaction process. The computational results are in good agreement with experimental observations, and the differences and similarities of the biomimetic complex and the enzymatic CDO center are highlighted. PMID:22091701

  17. Iron(III) complexes of certain tetradentate phenolate ligands as functional models for catechol dioxygenases

    Indian Academy of Sciences (India)

    Mallayan Palaniandavar; Marappan Velusamy; Ramasamy Mayilmurugan

    2006-11-01

    Catechol 1,2-dioxygenase (CTD) and protocatechuate 3,4-dioxygenase (PCD) are bacterial non-heme iron enzymes, which catalyse the oxidative cleavage of catechols to cis, cis-muconic acids with the incorporation of molecular oxygen via a mechanism involving a high-spin ferric centre. The iron(III) complexes of tripodal phenolate ligands containing N3O and N2O2 donor sets represent the metal binding region of the iron proteins. In our laboratory iron(III) complexes of mono- and bisphenolate ligands have been studied successfully as structural and functional models for the intradiol-cleaving catechol dioxygenase enzymes. The single crystal X-ray crystal structures of four of the complexes have been determined. One of the bis-phenolato complexes contains a FeN2O2Cl chromophore with a novel trigonal bipyramidal coordination geometry. The Fe-O-C bond angle of 136.1° observed for one of the iron(III) complex of a monophenolate ligand is very similar to that in the enzymes. The importance of the nearby sterically demanding coordinated -NMe2 group has been established and implies similar stereochemical constraints from the other ligated amino acid moieties in the 3,4-PCD enzymes, the enzyme activity of which is traced to the difference in the equatorial and axial Fe-O(tyrosinate) bonds (Fe-O-C, 133, 148°). The nature of heterocyclic rings of the ligands and the methyl substituents on them regulate the electronic spectral features, FeIII/FeII redox potentials and catechol cleavage activity of the complexes. Upon interacting with catecholate anions, two catecholate to iron(III) charge transfer bands appear and the low energy band is similar to that of catechol dioxygenase-substrate complex. Four of the complexes catalyze the oxidative cleavage of H2DBC by molecular oxygen to yield intradiol cleavage products. Remarkably, the more basic N-methylimidazole ring in one of the complexes facilitates the rate-determining productreleasing phase of the catalytic reaction. The present

  18. Trichloroethylene removal and oxidation toxicity mediated by toluene dioxygenase of Pseudomonas putida.

    OpenAIRE

    Heald, S.; Jenkins, R. O.

    1994-01-01

    Whole cells of Pseudomonas putida containing toluene dioxygenase were able to remove all detectable trichloroethylene (TCE) from assay mixtures. The capacity of cells to remove TCE was 77 microM/mg of protein with an initial rate of removal of 5.2 nmol/min/ng of protein. TCE oxidation resulted in a decrease in the growth rate of cultures and caused rapid cell death. Addition of dithiothreitol to assay mixtures increased the TCE removal capacity of cells by up to 67% but did not prevent TCE-me...

  19. Homogentisate 1,2 dioxygenase is expressed in human osteoarticular cells: implications in alkaptonuria.

    Science.gov (United States)

    Laschi, Marcella; Tinti, Laura; Braconi, Daniela; Millucci, Lia; Ghezzi, Lorenzo; Amato, Loredana; Selvi, Enrico; Spreafico, Adriano; Bernardini, Giulia; Santucci, Annalisa

    2012-09-01

    Alkaptonuria (AKU) results from defective homogentisate1,2-dioxygenase (HGD), causing degenerative arthropathy. The deposition of ochronotic pigment in joints is so far attributed to homogentisic acid produced by the liver, circulating in the blood and accumulating locally. Human normal and AKU osteoarticular cells were tested for HGD gene expression by RT-PCR, mono- and 2D-Western blotting. HGD gene expression was revealed in chondrocytes, synoviocytes, osteoblasts. Furthermore, HGD expression was confirmed by Western blotting, that also revealed the presence of five enzymatic molecular species. Our findings indicate that AKU osteoarticular cells produce the ochronotic pigment in loco and this may strongly contribute to induction of ochronotic arthropathy.

  20. Indoleamine 2,3-dioxygenase specific, cytotoxic T cells as immune regulators

    DEFF Research Database (Denmark)

    Sørensen, Rikke Bæk; Hadrup, Sine Reker; Svane, Inge Marie;

    2011-01-01

    Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme that is implicated in suppressing T-cell immunity in normal and pathologic settings. Here, we describe that spontaneous cytotoxic T-cell reactivity against IDO exists not only in patients with cancer but also in healthy persons. We......, this caused an increase in the production of the proinflammatory cytokines IL-6 and tumor necrosis factor-alpha while decreasing the IL-10 production. Finally, the addition of IDO-inducing agents (ie, the TLR9 ligand cytosine-phosphate- guanosine, soluble cytotoxic T lymphocyte-associated antigen 4...

  1. Compound-Specific Isotope Analysis of Nitroaromatic Contaminant Transformations by Nitroarene Dioxygenases

    Science.gov (United States)

    Pati, Sarah G.; Kohler, Hans-Peter E.; Hofstetter, Thomas B.

    2014-05-01

    Dioxygenation is an important biochemical reaction that often initiates the mineralization of recalcitrant organic contaminants such as nitroaromatic explosives, chlorinated benzenes, and polycyclic aromatic hydrocarbons. However, to assess the extent of dioxygenation in contaminated environments is difficult because of competing transformation processes and further reactions of the dioxygenation products. Compound-specific isotope analysis (CSIA) offers a new approach to reliably quantify biodegradation initiated by dioxygenation based on changes in stable isotope ratios of the pollutant. For CSIA it is essential to know the kinetic isotope effects (KIEs) pertinent to the dioxygenation mechanism of organic contaminants. Unfortunately, the range of KIEs of such reactions is poorly constrained although many dioxygenase enzymes with a broad substrate specificity have been reported. Dioxygenase enzymes usually exhibit complex reaction kinetics involving multiple substrates and substrate-specific binding modes which makes the determination of KIEs challenging. The goal of this study was to explore the magnitude and variability of 13C-, 2H-, and 15N-KIEs for the dioxygenation of one contaminant class, that is nitroaromatic contaminants (NACs). To this end, we investigated the C, H, and N isotope fractionation during the dioxygenation of nitrobenzene (NB), 2-nitrotoluene (2-NT), and 3-nitrotoluene (3-NT) by pure cultures, E. coli clones, cell extracts, and purified enzymes. From isotope fractionations measured in the substrates and reaction products, we determined dioxygenation KIEs for different combinations of the three substrates with nitrobenzene dioxygenase (NBDO) and 2-nitrotoluene dioxygenase (2NTDO). The 13C-, 2H-, and 15N-KIEs for the dioxygenation of NB by NBDO were consistent for all experimental systems considered (i.e., Comamonas sp. Strain JS765, E. coli clones, cell extracts of E. coli clones, and purified NBDO). This observation suggests that the isotope

  2. Structure of the 2, 4′-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP

    Energy Technology Data Exchange (ETDEWEB)

    Keegan, R.; Lebedev, A. [RAL, Harwell Oxford, Didcot OX11 0FA (United Kingdom); Erskine, P.; Guo, J.; Wood, S. P. [UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF (United Kingdom); Hopper, D. J. [Aberystwyth University, Penglais, Aberystwyth SY23 3DA Wales (United Kingdom); Rigby, S. E. J. [University of Manchester, 131 Princess Street, Manchester M1 7DN (United Kingdom); Cooper, J. B., E-mail: jon.cooper@ucl.ac.uk [UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF (United Kingdom); RAL, Harwell Oxford, Didcot OX11 0FA (United Kingdom)

    2014-09-01

    The first X-ray structure of a 2, 4′-dihydroxyacetophenone dioxygenase from Alcaligenes sp. 4HAP at a resolution of 2.2 Å is reported. This structure establishes that the enzyme adopts the cupin-fold, forming compact dimers with a pronounced hydrophobic interface between the monomers. Each monomer possesses a catalytic ferrous iron that is coordinated by three histidines (76, 78 and 114) and an additional ligand which has been putatively assigned as a carbonate, although formate and acetate are possibilities. The enzyme 2, 4′-dihydroxyacetophenone dioxygenase (DAD) catalyses the conversion of 2, 4′-dihydroxyacetophenone to 4-hydroxybenzoic acid and formic acid with the incorporation of molecular oxygen. Whilst the vast majority of dioxygenases cleave within the aromatic ring of the substrate, DAD is very unusual in that it is involved in C—C bond cleavage in a substituent of the aromatic ring. There is evidence that the enzyme is a homotetramer of 20.3 kDa subunits, each containing nonhaem iron, and its sequence suggests that it belongs to the cupin family of dioxygenases. In this paper, the first X-ray structure of a DAD enzyme from the Gram-negative bacterium Alcaligenes sp. 4HAP is reported, at a resolution of 2.2 Å. The structure establishes that the enzyme adopts a cupin fold, forming dimers with a pronounced hydrophobic interface between the monomers. The catalytic iron is coordinated by three histidine residues (76, 78 and 114) within a buried active-site cavity. The iron also appears to be tightly coordinated by an additional ligand which was putatively assigned as a carbonate dianion since this fits the electron density optimally, although it might also be the product formate. The modelled carbonate is located in a position which is highly likely to be occupied by the α-hydroxyketone group of the bound substrate during catalysis. Modelling of a substrate molecule in this position indicates that it will interact with many conserved amino acids in

  3. Evidence for leptin receptor isoforms heteromerization at the cell surface.

    Science.gov (United States)

    Bacart, Johan; Leloire, Audrey; Levoye, Angélique; Froguel, Philippe; Jockers, Ralf; Couturier, Cyril

    2010-06-01

    Leptin mediates its metabolic effects through several leptin receptor (LEP-R) isoforms. In humans, long (LEPRb) and short (LEPRa,c,d) isoforms are generated by alternative splicing. Most of leptin's effects are believed to be mediated by the OB-Rb isoform. However, the role of short LEPR isoforms and the possible existence of heteromers between different isoforms are poorly understood. Using BRET1 and optimized co-immunoprecipitation, we observed LEPRa/b and LEPRb/c heteromers located at the plasma membrane and stabilized by leptin. Given the widespread coexpression of LEPRa and LEPRb, our results suggest that LEPRa/b heteromers may represent a major receptor species in most tissues.

  4. Pivotal role of anthranilate dioxygenase genes in the adaptation of Burkholderia multivorans ATCC 17616 in soil.

    Science.gov (United States)

    Nishiyama, Eri; Ohtsubo, Yoshiyuki; Yamamoto, Yasuhiro; Nagata, Yuji; Tsuda, Masataka

    2012-05-01

    In our recent screen for soil-induced genes, the expression of andA operon (andAcAdAbAa) for anthranilate catabolism in Burkholderia multivorans ATCC 17616 was found to increase dramatically in a soil sample (Nishiyama et al., Environ Microbiol 12: 2539, 2010). The operon was preceded by andR encoding a putative transcriptional regulator for the andA operon. In this study, the andA promoter was induced by tryptophan and anthranilate in an andR-dependent manner. The andA promoter in a deletion mutant lacking tryptophan dioxygenase (one of enzymes for the catabolism of tryptophan to anthranilate) did not respond to tryptophan, indicating that not tryptophan but anthranilate is the effector of AndR. Although both anthranilate and tryptophan were under the detection levels in the soil sample, andA promoter showed higher activity in the soil sample than in a laboratory medium. Such induction required andR and was moderately dependent on the ferric uptake regulator (Fur). The proliferation ability of andAc mutant in the sterile soil was low compared with the co-incubated wild-type cells. These findings suggested that in the soil environment, anthranilate dioxygenase genes are induced by AndR and Fur, and play a pivotal role in the proliferation in the soil environment. PMID:22360670

  5. Oxidation of alkyl nitronates catalyzed by 2-nitropropane dioxygenase from Hansenula mrakii.

    Science.gov (United States)

    Mijatovic, Slavica; Gadda, Giovanni

    2008-05-01

    2-Nitropropane dioxygenase from Hansenula mrakii was expressed in Escherichia coli cells and purified in active and stable form using 60% saturation of ammonium sulfate and a single chromatographic step onto a DEAE column. MALDI-TOF mass spectrometric and spectrophotometric analyses of the flavin extracted by heat or acid denaturation of the enzyme indicated that FMN, and not FAD as erroneously reported previously, is present in a 1:1 stoichiometry with the protein. Inductively coupled plasma mass spectrometric analysis of the enzyme established that H. mrakii 2-nitropropane dioxygenase contains negligible amounts of iron, manganese, zinc, and copper ions, which are not catalytically relevant. Anaerobic substrate reduction and kinetic data using a Clark oxygen electrode to measure rates of oxygen consumption indicated that the enzyme is active on a broad range of alkyl nitronates, with a marked preference for unbranched substrates over propyl-2-nitronate. Interestingly, the enzyme reacts poorly, if at all, with nitroalkanes, as suggested by lack of both anaerobic reduction of the enzyme-bound flavin and consumption of oxygen with nitroethane, nitrobutane, and 2-nitropropane. Finally, both the tight binding of sulfite (K(d)=90 microM, at pH 8 and 15 degrees C) to the enzyme and the formation of the anionic flavosemiquinone upon anaerobic incubation with alkyl nitronates are consistent with the presence of a positively charged group in proximity of the N1-C2=O atoms of the FMN cofactor. PMID:18329375

  6. The Role of Indoleamine 2,3-Dioxygenase in a Mouse Model of Neuroinflammation-Induced Depression

    NARCIS (Netherlands)

    Dobos, Nikoletta; de Vries, Erik F. J.; Kema, Ido P.; Patas, Konstantinos; Prins, Marloes; Nijholt, Ingrid M.; Dierckx, Rudi A.; Korf, Jakob; den Boer, Johan A.; Luiten, Paul G. M.; Eisel, Ulrich L. M.; Borsello, Tiziana

    2012-01-01

    Indoleamine 2,3-dioxygenase (IDO), an enzyme which is activated by pro-inflammatory cytokines, has been suggested as a potential link between neuroinflammatory processes in neurodegenerative diseases (like Alzheimer's disease) and depression. The present study aimed to determine whether neuroinflamm

  7. p53 Family: Role of Protein Isoforms in Human Cancer

    Directory of Open Access Journals (Sweden)

    Jinxiong Wei

    2012-01-01

    Full Text Available TP53, TP63, and TP73 genes comprise the p53 family. Each gene produces protein isoforms through multiple mechanisms including extensive alternative mRNA splicing. Accumulating evidence shows that these isoforms play a critical role in the regulation of many biological processes in normal cells. Their abnormal expression contributes to tumorigenesis and has a profound effect on tumor response to curative therapy. This paper is an overview of isoform diversity in the p53 family and its role in cancer.

  8. Involvement of a flavosemiquinone in the enzymatic oxidation of nitroalkanes catalyzed by 2-nitropropane dioxygenase.

    Science.gov (United States)

    Francis, Kevin; Russell, Bethany; Gadda, Giovanni

    2005-02-18

    2-Nitropropane dioxygenase (EC 1.13.11.32) catalyzes the oxidation of nitroalkanes into their corresponding carbonyl compounds and nitrite. In this study, the ncd-2 gene encoding for the enzyme in Neurospora crassa was cloned, expressed in Escherichia coli, and the resulting enzyme was purified. Size exclusion chromatography, heat denaturation, and mass spectroscopic analyses showed that 2-nitropropane dioxygenase is a homodimer of 80 kDa, containing a mole of non-covalently bound FMN per mole of subunit, and is devoid of iron. With neutral nitroalkanes and anionic nitronates other than propyl-1- and propyl-2-nitronate, for which a non-enzymatic free radical reaction involving superoxide was established using superoxide dismutase, substrate oxidation occurs within the enzyme active site. The enzyme was more specific for nitronates than nitroalkanes, as suggested by the second order rate constant k(cat)/K(m) determined with 2-nitropropane and primary nitroalkanes with alkyl chain lengths between 2 and 6 carbons. The steady state kinetic mechanism with 2-nitropropane, nitroethane, nitrobutane, and nitrohexane, in either the neutral or anionic form, was determined to be sequential, consistent with oxygen reacting with a reduced form of enzyme before release of the carbonyl product. Enzyme-monitored turnover with ethyl nitronate as substrate indicated that the catalytically relevant reduced form of enzyme is an anionic flavin semiquinone, whose formation requires the substrate, but not molecular oxygen, as suggested by anaerobic substrate reduction with nitroethane or ethyl nitronate. Substrate deuterium kinetic isotope effects with 1,2-[(2)H(4)]nitroethane and 1,1,2-[(2)H(3) ethyl nitronate at pH 8 yielded normal and inverse effects on the k(cat)/K(m) value, respectively, and were negligible on the k(cat) value. The k(cat)/K(m) and k(cat) pH profiles with anionic nitronates showed the requirement of an acid, whereas those for neutral nitroalkanes were consistent with

  9. Cell-specific expression of TLR9 isoforms in inflammation.

    Science.gov (United States)

    McKelvey, Kelly J; Highton, John; Hessian, Paul A

    2011-02-01

    Toll-like receptors (TLRs) are key pattern recognition receptors during an immune response. With five isoforms of human TLR9 described, we hypothesised that differential expression of TLR9 isoforms in different cell types would result in variable contributions to the overall input from TLR9 during inflammation. We assessed the molecular expression of the TLR9 isoforms, TLR9-A, -C and -D. In normal peripheral blood mononuclear cells, B-lymphocytes express ∼100-fold more TLR9-A transcript than monocytes or T-lymphocytes, which predominantly express the TLR9-C transcript. Switches in isoform predominance accompany B-lymphocyte development. TLR9 protein expression in rheumatoid inflammatory lesions reflected the TLR9 isoform expression by immune cells. Herein we suggest that B-lymphocytes and plasmacytoid dendritic cells contribute the ∼3-fold higher TLR9-A transcript levels observed in inflamed synovium when compared to subcutaneous rheumatoid nodules. In contrast, macrophages and T-lymphocytes contribute the ∼4-fold higher TLR9-C transcript levels seen in nodules, compared to synovia. From protein sequence, predictions of subcellular localisation suggest TLR9-B may locate to the mitochondria, whereas TLR9-D adopts an opposing orientation in the endoplasmic reticulum. Consistent with this, structure models raise the possibility of alternative ligands for the TLR9-B and TLR9-D variants. Our results highlight differences in the expression of human TLR9 isoforms in normal and inflamed tissues, with differing contributions to inflammation.

  10. 1,2,3-Triazoles as inhibitors of indoleamine 2,3-dioxygenase 2 (IDO2).

    Science.gov (United States)

    Röhrig, Ute F; Majjigapu, Somi Reddy; Caldelari, Daniela; Dilek, Nahzli; Reichenbach, Patrick; Ascencao, Kelly; Irving, Melita; Coukos, George; Vogel, Pierre; Zoete, Vincent; Michielin, Olivier

    2016-09-01

    Indoleamine 2,3-dioxygenase 2 (IDO2) is a potential therapeutic target for the treatment of diseases that involve immune escape such as cancer. In contrast to IDO1, only a very limited number of inhibitors have been described for IDO2 due to inherent difficulties in expressing and purifying a functionally active, soluble form of the enzyme. Starting from our previously discovered highly efficient 4-aryl-1,2,3-triazole IDO1 inhibitor scaffold, we used computational structure-based methods to design inhibitors of IDO2 which we then tested in cellular assays. Our approach yielded low molecular weight inhibitors of IDO2, the most active displaying an IC50 value of 51μM for mIDO2, and twofold selectivity over hIDO1. These compounds could be useful as molecular probes to investigate the biological role of IDO2, and could inspire the design of new IDO2 inhibitors. PMID:27469130

  11. Homogentisate 1,2 Dioxygenase is Expressed in Human Osteoarticular Cells: Implications in Alkaptonuria

    Science.gov (United States)

    Laschi, Marcella; Tinti, Laura; Braconi, Daniela; Millucci, Lia; Ghezzi, Lorenzo; Amato, Loredana; Selvi, Enrico; Spreafico, Adriano; Bernardini, Giulia; Santucci, Annalisa

    2012-01-01

    Alkaptonuria (AKU) results from defective homogentisate1,2-dioxygenase (HGD), causing degenerative arthropathy. The deposition of ochronotic pigment in joints is so far attributed to homogentisic acid produced by the liver, circulating in the blood and accumulating locally. Human normal and AKU osteoarticular cells were tested for HGD gene expression by RT-PCR, mono- and 2D-Western blotting. HGD gene expression was revealed in chondrocytes, synoviocytes, osteoblasts. Furthermore, HGD expression was confirmed by Western blotting, that also revealed the presence of five enzymatic molecular species. Our findings indicate that AKU osteoarticular cells produce the ochronotic pigment in loco and this may strongly contribute to induction of ochronotic arthropathy. J. Cell. Physiol. 227: 3254–3257, 2012. © 2011 Wiley Periodicals, Inc. PMID:22105303

  12. Characterization of catechol 1,2-dioxygenase from cell extracts of Sphingomonas xenophaga QYY

    Institute of Scientific and Technical Information of China (English)

    M.Salah; Uddin

    2009-01-01

    Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. Characterization of the crude C12O showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C12O. It was suggested that strain QYY possessed an inducible and ferric-dependent C12O. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C12O was achieved by a HiTrap Q Sepharose column chromatography.

  13. Characterization of catechol 1,2-dioxygenase from cell extracts of Sphingomonas xenophaga QYY

    Institute of Scientific and Technical Information of China (English)

    GOU Min; QU YuanYuan; ZHOU JiTi; LI Ang; M.Salah Uddin

    2009-01-01

    Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C120) in cell extracts. Characterization of the crude C120 showed that the maximum activity was obtained at 40-70℃ and pH 7.8-8.8. Metal ions had different influences on the activity of crude C120. It was suggested that strain QYY possessed an inducible and ferric-dependent C120. Kinetic studies showed that the value of Vmax and Km was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C120 was achieved by a HiTrap Q Sepharose column chromatography.

  14. Mutations in the 4-hydroxyphenylpyruvate dioxygenase gene (HPD) in patients with tyrosinemia type III.

    Science.gov (United States)

    Rüetschi, U; Cerone, R; Pérez-Cerda, C; Schiaffino, M C; Standing, S; Ugarte, M; Holme, E

    2000-06-01

    Tyrosinemia type III (OMIM 276710) is an autosomal recessive disorder caused by the deficiency of 4-hydroxyphenylpyruvate dioxygenase (HPD), the second enzyme in the tyrosine catabolic pathway. The enzyme deficiency results in an accumulation and increased excretion of tyrosine and phenolic metabolites. Only a few cases with the disorder have been described, and the clinical spectrum of the disorder is unknown. Reported patients have presented with mental retardation or neurological symptoms or have been picked up by neonatal screening. We have identified four presumed pathogenic mutations (two missense and two nonsense mutations) in the HPD gene in three unrelated families encompassing four homozygous individuals and one compound heterozygous individual with tyrosinemia type III. Furthermore, a number of polymorphic mutations have been identified in the HPD gene. No correlation of the severity of the mutation and enzyme deficiency and mental function has been found; neither do the recorded tyrosine levels correlate with the clinical phenotype.

  15. Structural diversity and evolution of the N-terminal isoform-specific region of ecdysone receptor-A and -B1 isoforms in insects

    Directory of Open Access Journals (Sweden)

    Kubo Takeo

    2010-02-01

    Full Text Available Abstract Background The ecdysone receptor (EcR regulates various cellular responses to ecdysteroids during insect development. Insects have multiple EcR isoforms with different N-terminal A/B domains that contain the isoform-specific activation function (AF-1 region. Although distinct physiologic functions of the EcR isoforms have been characterized in higher holometabolous insects, they remain unclear in basal direct-developing insects, in which only A isoform has been identified. To examine the structural basis of the EcR isoform-specific AF-1 regions, we performed a comprehensive structural comparison of the isoform-specific region of the EcR-A and -B1 isoforms in insects. Results The EcR isoforms were newly identified in 51 species of insects and non-insect arthropods, including direct-developing ametabolous and hemimetabolous insects. The comprehensive structural comparison revealed that the isoform-specific region of each EcR isoform contained evolutionally conserved microdomain structures and insect subgroup-specific structural modifications. The A isoform-specific region generally contained four conserved microdomains, including the SUMOylation motif and the nuclear localization signal, whereas the B1 isoform-specific region contained three conserved microdomains, including an acidic activator domain-like motif. In addition, the EcR-B1 isoform of holometabolous insects had a novel microdomain at the N-terminal end. Conclusions Given that the nuclear receptor AF-1 is involved in cofactor recruitment and transcriptional regulation, the microdomain structures identified in the isoform-specific A/B domains might function as signature motifs and/or as targets for cofactor proteins that play essential roles in the EcR isoform-specific AF-1 regions. Moreover, the novel microdomain in the isoform-specific region of the holometabolous insect EcR-B1 isoform suggests that the holometabolous insect EcR-B1 acquired additional transcriptional

  16. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran

    International Nuclear Information System (INIS)

    Highlights: ► Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAELB400) metabolizes PCBs. ► Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. ► We tested how the mutations affect the PCB-degrading abilities of BphAELB400 variants. ► The same mutations also broaden the PCB substrate range of BphAELB400 variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAELB400) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAERR41, a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAELB400, metabolized a broader range of PCBs than BphAELB400. Hence, BphAERR41 was able to metabolize 2,6,2′,6′-, 3,4,3′,5′- and 2,4,3′,4′-tetrachlorobiphenyl that BphAELB400 is unable to metabolize. BphAERR41 was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAELB400 to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.

  17. Metabolism of chlorobiphenyls by a variant biphenyl dioxygenase exhibiting enhanced activity toward dibenzofuran

    Energy Technology Data Exchange (ETDEWEB)

    Viger, Jean-Francois; Mohammadi, Mahmood; Barriault, Diane [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada); Sylvestre, Michel, E-mail: Michel.Sylvestre@iaf.inrs.ca [Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, Laval, Quebec, Canada H4K 1C2 (Canada)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Burkholderia xenovorans LB400 biphenyl dioxygenase (BphAE{sub LB400}) metabolizes PCBs. Black-Right-Pointing-Pointer Asn338Gln/Leu409Phe double mutation speeds up electron transfer of enzyme reaction. Black-Right-Pointing-Pointer We tested how the mutations affect the PCB-degrading abilities of BphAE{sub LB400} variants. Black-Right-Pointing-Pointer The same mutations also broaden the PCB substrate range of BphAE{sub LB400} variants. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) catalyzes the dihydroxylation of biphenyl and of several polychlorinated biphenyls (PCBs) but it poorly oxidizes dibenzofuran. In this work we showed that BphAE{sub RR41}, a variant which was previously found to metabolize dibenzofuran more efficiently than its parent BphAE{sub LB400}, metabolized a broader range of PCBs than BphAE{sub LB400}. Hence, BphAE{sub RR41} was able to metabolize 2,6,2 Prime ,6 Prime -, 3,4,3 Prime ,5 Prime - and 2,4,3 Prime ,4 Prime -tetrachlorobiphenyl that BphAE{sub LB400} is unable to metabolize. BphAE{sub RR41} was obtained by changing Thr335Phe336Asn338Ile341Leu409 of BphAE{sub LB400} to Ala335Met336Gln338Val341Phe409. Site-directed mutagenesis was used to create combinations of each substitution, in order to assess their individual contributions. Data show that the same Asn338Glu/Leu409Phe substitution that enhanced the ability to metabolize dibenzofuran resulted in a broadening of the PCB substrates range of the enzyme. The role of these substitutions on regiospecificities toward selected PCBs is also discussed.

  18. 2,3-Dihydroxybiphenyl dioxygenase gene was first discovered in Arthrobacter sp. strain P J3

    Institute of Scientific and Technical Information of China (English)

    YANG MeiYing; MA PengDa; LI WenMing; LIU JinYing; LI Liang; ZHU XiaoJuan; WANG XingZhi

    2007-01-01

    Bacterium strain PJ3, isolated from wastewater and identified as Arthrobacter sp. bacterium based on its 16S rDNA gene, could use carbazole as the sole carbon, nitrogen and energy source. The genomic libraryof strain PJ3 was constructed and a positive clone JM109 (pUCW402) was screened out for the expression of dioxygenase by the ability to form yellow ring-fission product. A 2,3-dihydroxybiphenyl dioxygenase (23DHBD) gene of 933 bp was found in the 3360 bp exogenous fragment of pUCW402 by GenSCAN software and BLAST analysis. The phylogenetic analysis showed that 23DHBD from strain PJ3 formed a deep branch separate from a cluster containing most known 23DHBD in GenBank.Southern hybridization confirmed for the first time that the 23DHBD gene was from the genomic DNA of Arthrobacter sp. PJ3. In order to test the gene function, recombinant bacterium BL21 (pETW-8) was constructed to express 23DHBD. The expression level in BL21 (pETW-8) was highest compared with the recombinant bacteria JM109 (pUCW402) and strain PJ3. We observed that 23DHBD was not absolute specific. The enzyme activity was higher with 2,3-dihydroxybiphenyl as a substrate than with catechol.The substrate specificity assay suggested that 23DHBD was essential for cleavage of bi-cyclic aromatic compounds during the course of aromatic compound biodegradation in Arthrobacter sp. strain PJ3.

  19. Linolenate 9R-dioxygenase and allene oxide synthase activities of Lasiodiplodia theobromae.

    Science.gov (United States)

    Jernerén, Fredrik; Eng, Felipe; Hamberg, Mats; Oliw, Ernst H

    2012-01-01

    Jasmonic acid (JA) is synthesized from linolenic acid (18:3n-3) by sequential action of 13-lipoxygenase, allene oxide synthase (AOS), and allene oxide cyclase. The fungus Lasiodiplodia theobromae can produce large amounts of JA and was recently reported to form the JA precursor 12-oxophytodienoic acid. The objective of our study was to characterize the fatty acid dioxygenase activities of this fungus. Two strains of L. theobromae with low JA secretion (~0.2 mg/L medium) oxygenated 18:3n-3 to 5,8-dihydroxy-9Z,12Z,15Z-octadecatrienoic acid as well as 9R-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid, which was metabolized by an AOS activity into 9-hydroxy-10-oxo-12Z,15Z-octadecadienoic acid. Analogous conversions were observed with linoleic acid (18:2n-6). Studies using [11S-(2)H]18:2n-6 revealed that the putative 9R-dioxygenase catalyzed stereospecific removal of the 11R hydrogen followed by suprafacial attack of dioxygen at C-9. Mycelia from these strains of L. theobromae contained 18:2n-6 as the major polyunsaturated acid but lacked 18:3n-3. A third strain with a high secretion of JA (~200 mg/L) contained 18:3n-3 as a major fatty acid and produced 5,8-dihydroxy-9Z,12Z,15Z-octadecatrienoic acid from added 18:3n-3. This strain also lacked the JA biosynthetic enzymes present in higher plants. PMID:22048860

  20. Distinct functional interactions between actin isoforms and nonsarcomeric myosins.

    Directory of Open Access Journals (Sweden)

    Mirco Müller

    Full Text Available Despite their near sequence identity, actin isoforms cannot completely replace each other in vivo and show marked differences in their tissue-specific and subcellular localization. Little is known about isoform-specific differences in their interactions with myosin motors and other actin-binding proteins. Mammalian cytoplasmic β- and γ-actin interact with nonsarcomeric conventional myosins such as the members of the nonmuscle myosin-2 family and myosin-7A. These interactions support a wide range of cellular processes including cytokinesis, maintenance of cell polarity, cell adhesion, migration, and mechano-electrical transduction. To elucidate differences in the ability of isoactins to bind and stimulate the enzymatic activity of individual myosin isoforms, we characterized the interactions of human skeletal muscle α-actin, cytoplasmic β-actin, and cytoplasmic γ-actin with human myosin-7A and nonmuscle myosins-2A, -2B and -2C1. In the case of nonmuscle myosins-2A and -2B, the interaction with either cytoplasmic actin isoform results in 4-fold greater stimulation of myosin ATPase activity than was observed in the presence of α-skeletal muscle actin. Nonmuscle myosin-2C1 is most potently activated by β-actin and myosin-7A by γ-actin. Our results indicate that β- and γ-actin isoforms contribute to the modulation of nonmuscle myosin-2 and myosin-7A activity and thereby to the spatial and temporal regulation of cytoskeletal dynamics. FRET-based analyses show efficient copolymerization abilities for the actin isoforms in vitro. Experiments with hybrid actin filaments show that the extent of actomyosin coupling efficiency can be regulated by the isoform composition of actin filaments.

  1. Central Administration of Lipopolysaccharide Induces Depressive-like Behavior in Vivo and Activates Brain Indoleamine 2,3 Dioxygenase In Murine Organotypic Hippocampal Slice Cultures

    Directory of Open Access Journals (Sweden)

    Kavelaars Annemieke

    2010-08-01

    Full Text Available Abstract Background Transient stimulation of the innate immune system by an intraperitoneal injection of lipopolysaccharide (LPS activates peripheral and central expression of the tryptophan degrading enzyme indoleamine 2,3 dioxygenase (IDO which mediates depressive-like behavior. It is unknown whether direct activation of the brain with LPS is sufficient to activate IDO and induce depressive-like behavior. Methods Sickness and depressive-like behavior in C57BL/6J mice were assessed by social exploration and the forced swim test, respectively. Expression of cytokines and IDO mRNA was measured by real-time RT-PCR and cytokine protein was measured by enzyme-linked immunosorbent assays (ELISAs. Enzymatic activity of IDO was estimated as the amount of kynurenine produced from tryptophan as determined by high pressure liquid chromatography (HPLC with electrochemical detection. Results Intracerebroventricular (i.c.v. administration of LPS (100 ng increased steady-state transcripts of TNFα, IL-6 and the inducible isoform of nitric oxide synthase (iNOS in the hippocampus in the absence of any change in IFNγ mRNA. LPS also increased IDO expression and induced depressive-like behavior, as measured by increased duration of immobility in the forced swim test. The regulation of IDO expression was investigated using in situ organotypic hippocampal slice cultures (OHSCs derived from brains of newborn C57BL/6J mice. In accordance with the in vivo data, addition of LPS (10 ng/ml to the medium of OHSCs induced steady-state expression of mRNA transcripts for IDO that peaked at 6 h and translated into increased IDO enzymatic activity within 8 h post-LPS. This activation of IDO by direct application of LPS was preceded by synthesis and secretion of TNFα and IL-6 protein and activation of iNOS while IFNγ expression was undetectable. Conclusion These data establish that activation of the innate immune system in the brain is sufficient to activate IDO and induce

  2. HIV-1 Tat activates indoleamine 2,3 dioxygenase in murine organotypic hippocampal slice cultures in a p38 mitogen-activated protein kinase-dependent manner

    Directory of Open Access Journals (Sweden)

    Kelley Keith W

    2011-08-01

    Full Text Available Abstract Background We have established that activation of the tryptophan degrading enzyme indoleamine 2,3 dioxygenase (IDO mediates the switch from cytokine-induced sickness behavior to depressive-like behavior. Because human immunodeficiency virus type 1 (HIV-1 Tat protein causes depressive-like behavior in mice, we investigated its ability to activate IDO in organotypic hippocampal slice cultures (OHSCs derived from neonatal C57BL/6 mice. Methods Depressive-like behavior in C57BL/6J mice was assessed by the forced swim test. Expression of cytokines and IDO mRNA in OHSCs was measured by real-time RT-PCR and cytokine protein was measured by enzyme-linked immunosorbent assays (ELISAs. p38 MAPK phosphorylation was analyzed by western blot. Results Intracerebroventricular (i.c.v. administration of Tat (40 ng induced depressive-like behavior in the absence of sickness. Addition of Tat (40 ng/slice to the medium of OHSCs induced IDO steady-state mRNA that peaked at 6 h. This effect was potentiated by pretreatment with IFNγ. Tat also induced the synthesis and release of TNFα and IL-6 protein in the supernatant of the slices and increased expression of the inducible isoform of nitric oxide synthase (iNOS and the serotonin transporter (SERT. Tat had no effect on endogenous synthesis of IFNγ. To explore the mechanisms of Tat-induced IDO expression, slices were pretreated with the p38 mitogen-activated protein kinase (MAPK inhibitor SB 202190 for 30 min before Tat treatment. SB 202190 significantly decreased IDO expression induced by Tat, and this effect was accompanied by a reduction of Tat-induced expression of TNFα, IL-6, iNOS and SERT. Conclusion These data establish that Tat induces IDO expression via an IFNγ-independent mechanism that depends upon activation of p38 MAPK. Targeting IDO itself or the p38 MAPK signaling pathway could provide a novel therapy for comorbid depressive disorders in HIV-1-infected patients.

  3. Structure of the Dioxygenase AsqJ: Mechanistic Insights into a One-Pot Multistep Quinolone Antibiotic Biosynthesis

    KAUST Repository

    Bräuer, Alois

    2015-11-10

    © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Multienzymatic cascades are responsible for the biosynthesis of natural products and represent a source of inspiration for synthetic chemists. The FeII/α-ketoglutarate-dependent dioxygenase AsqJ from Aspergillus nidulans is outstanding because it stereoselectively catalyzes both a ferryl-induced desaturation reaction and epoxidation on a benzodiazepinedione. Interestingly, the enzymatically formed spiro epoxide spring-loads the 6,7-bicyclic skeleton for non-enzymatic rearrangement into the 6,6-bicyclic scaffold of the quinolone alkaloid 4′-methoxyviridicatin. Herein, we report different crystal structures of the protein in the absence and presence of synthesized substrates, surrogates, and intermediates that mimic the various stages of the reaction cycle of this exceptional dioxygenase.

  4. Differential regulation of renal phospholipase C isoforms by catecholamines.

    Science.gov (United States)

    Yu, P Y; Asico, L D; Eisner, G M; Jose, P A

    1995-01-01

    Dopamine and D1 agonists and NE all increase phosphatidyl inositol-specific phospholipase C (PLC) activity, but whereas dopamine produces a natriuresis, NE has an antinatriuretic effect. To determine if catecholamines differentially regulate the expression of PLC isoforms, we infused fenoldopam, a D1 agonist, or pramipexole, a D1/D2 agonist, intravenously or infused fenoldopam or NE into the renal artery of anesthetized rats. After 3-4 h of infusion, when the expected natriuresis (fenoldopam or pramipexole) or antinatriuresis (NE) occurred, the kidneys were removed for analysis of PLC isoform protein expression activity. Western blot analysis revealed that in renal cortical membranes, fenoldopam and pramipexole increased expression of PLC beta 1 and decreased expression of PLC gamma 1; PLC delta was unchanged. In the cytosol, pramipexole and fenoldopam increased expression of both PLC beta 1 and PLC gamma 1. No effects were noted in the medulla. A preferential D1 antagonist, SKF 83742, which by itself had no effect, blocked the effects of pramipexole, thus confirming the involvement of the D1 receptor. In contrast, NE also increased PLC beta 1 but did not affect PLC gamma 1 protein expression in membranes. The changes in PLC isoform expression were accompanied by similar changes in PLC isoform activity. These studies demonstrate for the first time differential regulation of PLC isoforms by catecholamines. PMID:7814630

  5. SURVIV for survival analysis of mRNA isoform variation.

    Science.gov (United States)

    Shen, Shihao; Wang, Yuanyuan; Wang, Chengyang; Wu, Ying Nian; Xing, Yi

    2016-01-01

    The rapid accumulation of clinical RNA-seq data sets has provided the opportunity to associate mRNA isoform variations to clinical outcomes. Here we report a statistical method SURVIV (Survival analysis of mRNA Isoform Variation), designed for identifying mRNA isoform variation associated with patient survival time. A unique feature and major strength of SURVIV is that it models the measurement uncertainty of mRNA isoform ratio in RNA-seq data. Simulation studies suggest that SURVIV outperforms the conventional Cox regression survival analysis, especially for data sets with modest sequencing depth. We applied SURVIV to TCGA RNA-seq data of invasive ductal carcinoma as well as five additional cancer types. Alternative splicing-based survival predictors consistently outperform gene expression-based survival predictors, and the integration of clinical, gene expression and alternative splicing profiles leads to the best survival prediction. We anticipate that SURVIV will have broad utilities for analysing diverse types of mRNA isoform variation in large-scale clinical RNA-seq projects. PMID:27279334

  6. Indoleamine 2,3-Dioxygenase 1 (Ido1) Is Involved in the Control of Mouse Caput Epididymis Immune Environment

    OpenAIRE

    Aicha Jrad-Lamine; Joelle Henry-Berger; Christelle Damon-Soubeyrand; Fabrice Saez; Ayhan Kocer; Laurent Janny; Hanae Pons-Rejraji; MUNN, DAVID H.; Mellor, Andrew L.; Najoua Gharbi; Rémi Cadet; Rachel Guiton; Aitken, Robert J.; Joël R Drevet

    2013-01-01

    The epididymis maintains a state of immune tolerance towards spermatozoa while also protecting them and itself against infection and acute inflammation. The immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (Ido1) participates in this delicate local equilibrium. Using the mouse Ido1(-/-) model, we show here that the absence of IDO1 expression leads in the epididymis but not in serum to (1) an increase in the inflammatory state as evidenced by changes in the content of cytokines and chemo...

  7. THE ROLE OF 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE IN ENHANCEMENT OF SOLID-PHASE ELECTRON TRANSFER BY SHEWANELLA ONEIDENSIS MR-1

    Energy Technology Data Exchange (ETDEWEB)

    Turick, C; Amy Ekechukwu, A

    2007-06-01

    While mechanistic details of dissimilatory metal reduction are far from being understood, it is postulated that the electron transfer to solid metal oxides is mediated by outer membrane-associated c-type cytochromes and redox active electron shuttling compounds. This study focuses on the production of homogensitate in Shewanella oneidensis MR-1, an intermediate of tyrosine degradation pathway, which is a precursor of a redox cycling metabolite, pyomelanin. In this study, we determined that two enzymes involved in this pathway, 4-hydroxyphenylpyruvate dioxygenase (4HPPD) and homogentisate 1,2-dioxygenase are responsible for homogentisate production and oxidation, respectively. Inhibition of 4-HPPD activity with the specific inhibitor sulcotrione (2-(2-chloro-4-methane sulfonylbenzoyl)-1,3-cyclohexanedione), and deletion of melA, a gene encoding 4-HPPD, resulted in no pyomelanin production by S. oneidensis MR-1. Conversely, deletion of hmgA which encodes the putative homogentisate 1,2-dioxygenase, resulted in pyomelanin overproduction. The efficiency and rates, with which MR-1 reduces hydrous ferric oxide, were directly linked to the ability of mutant strains to produce pyomelanin. Electrochemical studies with whole cells demonstrated that pyomelanin substantially increases the formal potential (E{sup o}{prime}) of S. oneidensis MR-1. Based on this work, environmental production of pyomelanin likely contributes to an increased solid-phase metal reduction capacity in Shewanella oneidensis.

  8. Crystallization and preliminary crystallographic analysis of 2-aminophenol 1,6-dioxygenase complexed with substrate and with an inhibitor.

    Science.gov (United States)

    Li, De-Feng; Zhang, Jia-Yue; Hou, Yanjie; Liu, Lei; Liu, Shuang-Jiang; Liu, Wei

    2012-11-01

    Dioxygen activation implemented by nonhaem Fe(II) enzymes containing the 2-His-1-carboxylate facial triad has been extensively studied in recent years. Extradiol dioxygenase is the archetypal member of this superfamily and catalyzes the oxygenolytic ring opening of catechol analogues. Here, the crystallization and preliminary X-ray analysis of 2-aminophenol 1,6-dioxygenase, an enzyme representing a minor subset of extradiol dioxygenases that catalyze the fission of 2-aminophenol rather than catecholic compounds, is reported. Crystals of the holoenzyme with FeII and of complexes with the substrate 2-aminophenol and the suicide inhibitor 4-nitrocatechol were grown using the cocrystallization method under the same conditions as used for the crystallization of the apoenzyme. The crystals belonged to space group C2 and diffracted to 2.3-2.7 Å resolution; the crystal that diffracted to the highest resolution had unit-cell parameters a=270.24, b=48.39, c=108.55 Å, β=109.57°. All X-ray data sets collected from diffraction-quality crystals were suitable for structure determination.

  9. An aryl dioxygenase shows remarkable double dioxygenation capacity for diverse bis-aryl compounds, provided they are carbocyclic.

    Science.gov (United States)

    Overwin, Heike; González, Myriam; Méndez, Valentina; Seeger, Michael; Wray, Victor; Hofer, Bernd

    2016-09-01

    The bacterial dioxygenation of mono- or polycyclic aromatic compounds is an intensely studied field. However, only in a few cases has the repeated dioxygenation of a substrate possessing more than a single aromatic ring been described. We previously characterized the aryl-hydroxylating dioxygenase BphA-B4h, an artificial hybrid of the dioxygenases of the biphenyl degraders Burkholderia xenovorans LB400 and Pseudomonas sp. strain B4-Magdeburg, which contains the active site of the latter enzyme, as an exceptionally powerful biocatalyst. We now show that this dioxygenase possesses a remarkable capacity for the double dioxygenation of various bicyclic aromatic compounds, provided that they are carbocyclic. Two groups of biphenyl analogues were examined: series A compounds containing one heterocyclic aromatic ring and series B compounds containing two homocyclic aromatic rings. Whereas all of the seven partially heterocyclic biphenyl analogues were solely dioxygenated in the homocyclic ring, four of the six carbocyclic bis-aryls were converted into ortho,meta-hydroxylated bis-dihydrodiols. Potential reasons for failure of heterocyclic dioxygenations are discussed. The obtained bis-dihydrodiols may, as we also show here, be enzymatically re-aromatized to yield the corresponding tetraphenols. This opens a way to a range of new polyphenolic products, a class of compounds known to exert multiple biological activities. Several of the obtained compounds are novel molecules. PMID:27147529

  10. Molecular mechanism of strict substrate specificity of an extradiol dioxygenase, DesB, derived from Sphingobium sp. SYK-6.

    Directory of Open Access Journals (Sweden)

    Keisuke Sugimoto

    Full Text Available DesB, which is derived from Sphingobium sp. SYK-6, is a type II extradiol dioxygenase that catalyzes a ring opening reaction of gallate. While typical extradiol dioxygenases show broad substrate specificity, DesB has strict substrate specificity for gallate. The substrate specificity of DesB seems to be required for the efficient growth of S. sp. SYK-6 using lignin-derived aromatic compounds. Since direct coordination of hydroxyl groups of the substrate to the non-heme iron in the active site is a critical step for the catalytic reaction of the extradiol dioxygenases, the mechanism of the substrate recognition and coordination of DesB was analyzed by biochemical and crystallographic methods. Our study demonstrated that the direct coordination between the non-heme iron and hydroxyl groups of the substrate requires a large shift of the Fe (II ion in the active site. Mutational analysis revealed that His124 and His192 in the active site are essential to the catalytic reaction of DesB. His124, which interacts with OH (4 of the bound gallate, seems to contribute to proper positioning of the substrate in the active site. His192, which is located close to OH (3 of the gallate, is likely to serve as the catalytic base. Glu377' interacts with OH (5 of the gallate and seems to play a critical role in the substrate specificity. Our biochemical and structural study showed the substrate recognition and catalytic mechanisms of DesB.

  11. The FTO (fat mass and obesity associated gene codes for a novel member of the non-heme dioxygenase superfamily

    Directory of Open Access Journals (Sweden)

    Andrade-Navarro Miguel A

    2007-11-01

    Full Text Available Abstract Background Genetic variants in the FTO (fat mass and obesity associated gene have been associated with an increased risk of obesity. However, the function of its protein product has not been experimentally studied and previously reported sequence similarity analyses suggested the absence of homologs in existing protein databases. Here, we present the first detailed computational analysis of the sequence and predicted structure of the protein encoded by FTO. Results We performed a sequence similarity search using the human FTO protein as query and then generated a profile using the multiple sequence alignment of the homologous sequences. Profile-to-sequence and profile-to-profile based comparisons identified remote homologs of the non-heme dioxygenase family. Conclusion Our analysis suggests that human FTO is a member of the non-heme dioxygenase (Fe(II- and 2-oxoglutarate-dependent dioxygenases superfamily. Amino acid conservation patterns support this hypothesis and indicate that both 2-oxoglutarate and iron should be important for FTO function. This computational prediction of the function of FTO should suggest further steps for its experimental characterization and help to formulate hypothesis about the mechanisms by which it relates to obesity in humans.

  12. Proteogenomic Analysis Identifies a Novel Human SHANK3 Isoform

    Directory of Open Access Journals (Sweden)

    Fahad Benthani

    2015-05-01

    Full Text Available Mutations of the SHANK3 gene have been associated with autism spectrum disorder. Individuals harboring different SHANK3 mutations display considerable heterogeneity in their cognitive impairment, likely due to the high SHANK3 transcriptional diversity. In this study, we report a novel interaction between the Mutated in colorectal cancer (MCC protein and a newly identified SHANK3 protein isoform in human colon cancer cells and mouse brain tissue. Hence, our proteogenomic analysis identifies a new human long isoform of the key synaptic protein SHANK3 that was not predicted by the human reference genome. Taken together, our findings describe a potential new role for MCC in neurons, a new human SHANK3 long isoform and, importantly, highlight the use of proteomic data towards the re-annotation of GC-rich genomic regions.

  13. Laminin isoforms in endothelial and perivascular basement membranes

    Science.gov (United States)

    Yousif, Lema F.; Di Russo, Jacopo; Sorokin, Lydia

    2013-01-01

    Laminins, one of the major functional components of basement membranes, are found underlying endothelium, and encasing pericytes and smooth muscle cells in the vessel wall. Depending on the type of blood vessel (capillary, venule, postcapillary venule, vein or artery) and their maturation state, both the endothelial and mural cell phenotype vary, with associated changes in laminin isoform expression. Laminins containing the α4 and α5 chains are the major isoforms found in the vessel wall, with the added contribution of laminin α2 in larger vessels. We here summarize current data on the precise localization of these laminin isoforms and their receptors in the different layers of the vessel wall, and their potential contribution to vascular homeostasis. PMID:23263631

  14. Oxygenation properties and isoform diversity of snake hemoglobins

    DEFF Research Database (Denmark)

    Storz, Jay F.; Natarajan, Chandrasekhar; Moriyama, Hideaki;

    2015-01-01

    Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer- dimer dissociation. However, standardized comparative data are lacking...... for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying - and -type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2......) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis...

  15. Identification and characterization of novel NuMA isoforms

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin, E-mail: petersdu2112@hotmail.com [Key Laboratory for Cell Proliferation and Regulation of the Ministry of Education, Beijing Normal University, Beijing (China); Xu, Zhe [Department of Clinical Laboratory Diagnosis, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); Core Laboratory for Clinical Medical Research, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); He, Dacheng [Key Laboratory for Cell Proliferation and Regulation of the Ministry of Education, Beijing Normal University, Beijing (China); Lu, Guanting, E-mail: guantlv@126.com [Beijing DnaLead Science and Technology Co., LTD, Beijing (China)

    2014-11-21

    Highlights: • Seven NuMA isoforms generated by alternative splicing were categorized into 3 groups: long, middle and short. • Both exons 15 and 16 in long NuMA were “hotspot” for alternative splicing. • Lower expression of short NuMA was observed in cancer cells compared with nonneoplastic controls. • Distinct localization pattern of short isoforms indicated different function from that of long and middle NuMA. - Abstract: The large nuclear mitotic apparatus (NuMA) has been investigated for over 30 years with functions related to the formation and maintenance of mitotic spindle poles during mitosis. However, the existence and functions of NuMA isoforms generated by alternative splicing remains unclear. In the present work, we show that at least seven NuMA isoforms (categorized into long, middle and short groups) generated by alternative splicing from a common NuMA mRNA precursor were discovered in HeLa cells and these isoforms differ mainly at the carboxyl terminus and the coiled-coil domains. Two “hotspot” exons with molecular mass of 3366-nt and 42-nt tend to be spliced during alternative splicing in long and middle groups. Furthermore, full-length coding sequences of long and middle NuMA obtained by using fusion PCR were constructed into GFP-tagged vector to illustrate their cellular localization. Long NuMA mainly localized in the nucleus with absence from nucleoli during interphase and translocated to the spindle poles in mitosis. Middle NuMA displayed the similar cell cycle-dependent distribution pattern as long NuMA. However, expression of NuMA short isoforms revealed a distinct subcellular localization. Short NuMA were present in the cytosol during the whole cycle, without colocalization with mitotic apparatus. These results have allowed us tentatively to explore a new research direction for NuMA’s various functions.

  16. Characterization of arene di-oxygenases involved in polycyclic aromatic hydrocarbons biodegradation in Mycobacterium sp. 6PY1; Caracterisation d'arene dioxygenases impliquees dans la biodegradation des hydrocarbures aromatiques polycycliques chez Mycobacterium sp. 6PY1

    Energy Technology Data Exchange (ETDEWEB)

    Kuony, S.

    2005-06-15

    This thesis deals with the bacterial biodegradation of pollutants called polycyclic aromatic hydrocarbons (PAHs). The bacterium Mycobacterium sp. 6PY1 was isolated from a polluted soil for its ability to use pyrene, a 4-ring PAH, as sole source of carbon and energy. To learn about the pyrene metabolic pathway, the identification of the enzymes involved in this process has been undertaken using a proteomic approach. This approach revealed the occurrence of two ring-hydroxylating di-oxygenases in strain 6PY1, which could catalyze the initial attack of pyrene. The goal of this study was to clone the genes encoding the di-oxygenases identified in Mycobacterium sp. 6PY1, over-express these genes in an heterologous system in order to facilitate the purification of the corresponding enzymes, and determine the biochemical and catalytic properties of these enzymes. The pdoA1B1 genes encoding the terminal component of a di-oxygenase were cloned and over-expressed in Escherichia coli. The catalytic properties of this enzyme, called Pdo1, were determined in vivo by measuring the oxidation products of 2- to 4-ring PAHs by gas chromatography coupled to mass spectrometry (GC-MS). Analysis of the selectivity of the enzyme, as determined using GC-MS, showed that Pdo1 preferentially oxidized 3- or 4-ring PAHs, including phenanthrene and pyrene, but was inactive on di-aromatic compounds such as naphthalene and biphenyl. Pdo1 was unstable and was therefore purified in inactive form. The genes encoding a second di-oxygenase component were found in a locus containing two other catabolic genes. The pdoA2B2 genes encoded an enzyme called Pdo2 showing a narrow specificity towards 2- to 3-ring PAHs, and a high preference for phenanthrene. Pdo2 is an a3{beta}3 hexamer, containing [2Fe-2S] Rieske clusters which confer it a characteristic absorbance spectrum. A third set of genes possibly encoding another di-oxygenase was discovered in the genome of Mycobacterium sp. 6PY1. This set is closely

  17. A Review of Metallothionein Isoforms and their Role in Pathophysiology

    OpenAIRE

    Senthil kumar M; Manisenthil Kumar KT; Shyam Sunder A; Thirumoorthy N; Ganesh GNK; Chatterjee Malay

    2011-01-01

    Abstract The Metallothionein (MT) is a protein which has several interesting biological effects and has been demonstrated increase focus on the role of MT in various biological systems in the past three decades. The studies on the role of MT were limited with few areas like apoptosis and antioxidants in selected organs even fifty years after its discovery. Now acknowledge the exploration of various isoforms of MT such as MT-I, MT-II, MT-III and MT-IV and other isoforms in various biological s...

  18. ApoE isoform-dependent changes in hippocampal synaptic function

    Directory of Open Access Journals (Sweden)

    Sullivan Patrick M

    2009-05-01

    Full Text Available Abstract The lipoprotein receptor system in the hippocampus is intimately involved in the modulation of synaptic transmission and plasticity. The association of specific apoE isoform expression with human neurodegenerative disorders has focused attention on the role of these apoE isoforms in lipoprotein receptor-dependent synaptic modulation. In the present study, we used the apoE2, apoE3 and apoE4 targeted replacement (TR mice along with recombinant human apoE isoforms to determine the role of apoE isoforms in hippocampus area CA1 synaptic function. While synaptic transmission is unaffected by apoE isoform, long-term potentiation (LTP is significantly enhanced in apoE4 TR mice versus apoE2 TR mice. ApoE isoform-dependent differences in LTP induction require NMDA-receptor function, and apoE isoform expression alters activation of both ERK and JNK signal transduction. Acute application of specific apoE isoforms also alters LTP induction while decreasing NMDA-receptor mediated field potentials. Furthermore, acute apoE isoform application does not have the same effects on ERK and JNK activation. These findings demonstrate specific, isoform-dependent effects of human apoE isoforms on adult hippocampus synaptic plasticity and highlight mechanistic differences between chronic apoE isoform expression and acute apoE isoform exposure.

  19. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pravindra; Mohammadi, Mahmood; Dhindwal, Sonali; Pham, Thi Thanh My; Bolin, Jeffrey T.; Sylvestre, Michel (INRS); (IIT-India); (Purdue)

    2012-06-28

    The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAE{sub LB400} and obtained BphAE{sub RR41}. This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAE{sub LB400}. However, the regiospecificity of BphAE{sub RR41} toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAE{sub RR41} obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAE{sub RR41}:dibenzofuran. In BphAE{sub RR41}:2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAE{sub RR41}:dibenzofuran, and strong enough in the BphAE{sub RR41}:2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.

  20. The key role of water in the dioxygenase function of Escherichia coli flavohemoglobin.

    Science.gov (United States)

    Ferreiro, Dardo N; Boechi, Leonardo; Estrin, Darío A; Martí, Marcelo A

    2013-02-01

    Flavohemoglobins (FHbs) are members of the globin superfamily, widely distributed among prokaryotes and eukaryotes that have been shown to carry out nitric oxide dioxygenase (NOD) activity. In prokaryotes, such as Escherichia coli, NOD activity is a defence mechanism against the NO release by the macrophages of the hosts' immune system during infection. Because of that, FHbs have been studied thoroughly and several drugs have been developed in an effort to fight infectious processes. Nevertheless, the protein's structural determinants involved in the NOD activity are still poorly understood. In this context, the aim of the present work is to unravel the molecular basis of FHbs structural dynamics-to-function relationship using state of the art computer simulation tools. In an effort to fulfill this goal, we studied three key processes that determine NOD activity, namely i) ligand migration into the active site ii) stabilization of the coordinated oxygen and iii) intra-protein electron transfer (ET). Our results allowed us to determine key factors related to all three processes like the presence of a long hydrophobic tunnel for ligand migration, the presence of a water mediated hydrogen bond to stabilize the coordinated oxygen and therefore achieve a high affinity, and the best possible ET paths between the FAD and the heme, where water molecules play an important role. Taken together the presented results close an important gap in our understanding of the wide and diverse globin structural-functional relationships. PMID:23220591

  1. Salmonella overcomes tumor immune tolerance by inhibition of tumor indoleamine 2, 3-dioxygenase 1 expression.

    Science.gov (United States)

    Kuan, Yu-Diao; Lee, Che-Hsin

    2016-01-01

    Over the past decades, Salmonella has been proven capable of inhibiting tumor growth. It can specifically target tumors and due to its facultative anaerobic property, can be more penetrative than other drug therapies. However, the molecular mechanism by which Salmonella inhibits tumor growth is still incompletely known. The antitumor therapeutic effect mediated by Salmonella is associated with an inflammatory immune response at the tumor site and a T cell-dependent immune response. Many tumors have been proven to have a high expression of indoleamine 2, 3-dioxygenase 1 (IDO), which is a rate-limiting enzyme that catalyzes tryptophan to kynurenine, thus causing immune tolerance within the tumor microenvironment. With decreased expression of IDO, increased immune response can be observed, which might be helpful when developing cancer immunotherapy. The expression of IDO was decreased after tumor cells were infected with Salmonella. In addition, Western blot analysis showed that the expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70s6K) in tumor cells were decreased after Salmonella infection. In conclusion, our results indicate that Salmonella inhibits IDO expression and plays a crucial role in anti-tumor therapy, which might be a promising strategy combined with other cancer treatments.

  2. Lignans from Carthamus tinctorius suppress tryptophan breakdown via indoleamine 2,3-dioxygenase.

    Science.gov (United States)

    Kuehnl, Susanne; Schroecksnadel, Sebastian; Temml, Veronika; Gostner, Johanna M; Schennach, Harald; Schuster, Daniela; Schwaiger, Stefan; Rollinger, Judith M; Fuchs, Dietmar; Stuppner, Hermann

    2013-10-15

    Seed extracts of Carthamus tinctorius L. (Asteraceae), safflower, have been traditionally used to treat coronary disease, thrombotic disorders, and menstrual problems but also against cancer and depression. A possible effect of C. tinctorius compounds on tryptophan-degrading activity of enzyme indoleamine 2,3-dioxygenase (IDO) could explain many of its activities. To test for an effect of C. tinctorius extracts and isolated compounds on cytokine-induced IDO activity in immunocompetent cells in vitro methanol and ethylacetate seed extracts were prepared from cold pressed seed cakes of C. tinctorius and three lignan derivatives, trachelogenin, arctigenin and matairesinol were isolated. The influence on tryptophan breakdown was investigated in peripheral blood mononuclear cells (PBMCs). Effects were compared to neopterin production in the same cellular assay. Both seed extracts suppressed tryptophan breakdown in stimulated PBMC. The three structurally closely related isolates exerted differing suppressive activity on PBMC: arctigenin (IC50 26.5μM) and trachelogenin (IC50 of 57.4μM) showed higher activity than matairesinol (IC50 >200μM) to inhibit tryptophan breakdown. Effects on neopterin production were similar albeit generally less strong. Data show an immunosuppressive property of compounds which slows down IDO activity. The in vitro results support the view that some of the anti-inflammatory, anticancer and antidepressant properties of C. tinctorius lignans might relate to their suppressive influence on tryptophan breakdown. PMID:23867649

  3. On the substrate- and stereospecificity of the plant carotenoid cleavage dioxygenase 7

    KAUST Repository

    Bruno, Mark

    2014-05-01

    Strigolactones are phytohormones synthesized from carotenoids via a stereospecific pathway involving the carotenoid cleavage dioxygenases 7 (CCD7) and 8. CCD7 cleaves 9-cis-β-carotene to form a supposedly 9-cis-configured β-apo-10′-carotenal. CCD8 converts this intermediate through a combination of yet undetermined reactions into the strigolactone-like compound carlactone. Here, we investigated the substrate and stereo-specificity of the Arabidopsis and pea CCD7 and determined the stereo-configuration of the β-apo-10′-carotenal intermediate by using Nuclear Magnetic Resonance Spectroscopy. Our data unequivocally demonstrate the 9-cis-configuration of the intermediate. Both CCD7s cleave different 9-cis-carotenoids, yielding hydroxylated 9-cis-apo-10′-carotenals that may lead to hydroxylated carlactones, but show highest affinity for 9-cis-β-carotene. © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  4. Pyrazolone-quinazolone hybrids: a novel class of human 4-hydroxyphenylpyruvate dioxygenase inhibitors.

    Science.gov (United States)

    Xu, Yu-Ling; Lin, Hong-Yan; Cao, Run-Jie; Ming, Ze-Zhong; Yang, Wen-Chao; Yang, Guang-Fu

    2014-10-01

    4-Hydroxyphenylpyruvate dioxygenase (HPPD), converting 4-hydroxyphenylpyruvate acid to homogentisate, is an important target for treating type I tyrosinemia and alkaptonuria due to its significant role in tyrosine catabolism. However, only one commercial drug, NTBC, also known as nitisinone, has been available for clinical use so far. Herein, we have elucidated the structure-based design of a series of pyrazolone-quinazolone hybrids that are novel potent human HPPD inhibitors through the successful integration of various techniques including computational simulations, organic synthesis, and biochemical characterization. Most of the new compounds displayed potent inhibitory activity against the recombinant human HPPD in nanomolar range. Compounds 3h and 3u were identified as the most potent candidates with Ki values of around 10 nM against human HPPD, about three-fold more potent than NTBC. Molecular modeling indicated that the interaction between the pyrazolone ring and ferrous ion, and the hydrophobic interaction of quinazolone with its surrounding residues, such as Phe347 and Phe364, contributed greatly to the high potency of these inhibitors. Therefore, compounds 3h and 3u could be potentially useful for the treatment of type I tyrosinemia and other diseases with defects in tyrosine degradation. PMID:25182962

  5. Functional expression of a valencene dioxygenase from Pleurotus sapidus in E. coli.

    Science.gov (United States)

    Zelena, Kateryna; Krings, Ulrich; Berger, Ralf G

    2012-03-01

    Valencene dioxygenase (ValOx) from the edible basidiomycete Pleurotus sapidus converted the sesquiterpene (+)-valencene to the valuable grapefruit flavour (+)-nootkatone and to nootkatols through intermediate hydroperoxides. Expression of the enzyme was carried out in the cytosol and periplasm of Escherichia coli. The heterologous production led to high yields of inclusion bodies. The poor yield of soluble recombinant protein was improved by various strategies including cold shock expression, chaperone co-expression, and employment of mutant E. coli strains. Up to 60 mg of the biologically active, soluble ValOx was produced by cold shock under control of the cspA promoter at 8 °C in the BL21(DE3)Star strain and co-expression of the E. coli trigger factor. The recombinant enzyme, purified using the N-terminal His tag, showed the catalytic properties of the wild-type enzyme, as was confirmed by the LC-MS analysis of hydroperoxide intermediates and GC-MS analysis of the volatile products. PMID:22264428

  6. The Immunoregulatory Function of Indoleamine 2, 3 Dioxygenase and Its Application in Allotransplantation

    Directory of Open Access Journals (Sweden)

    Reza B. Jalili

    2007-12-01

    Full Text Available Indolemine 2, 3-dioxygenase (IDO is a cytosolic monomeric hemoprotein enzyme that catalyses tryptophan, the least available essential amino acid in the human body, to N-formylkynurenine, which in turn rapidly degrades to give kynurenine. IDO is expressed in different tissues, especially and prominently in some subsets of antigen presenting cells (APCs of lymphoid organs and also in the placenta of human and other mammals. Expression of IDO by certain dendritic cells, monocytes and macrophages has a regulatory effect on T cells probably by providing a tryptophan-deficient microenvironment and/or accumulation of toxic metabolites of tryptophan. This immunomodulatory function of IDO plays an essential role in different physiological and pathological states. IDO was shown to prevent rejection of the fetus during pregnancy, possibly by inhibiting alloreactive T cells. Moreover, IDO expression in APCs was suggested to control autoreactive immune responses. In this review we discuss the molecular and biological characteristics of IDO and its function in immune system as well as the potential application of this enzyme in improving the outcome of allogeneic transplantation as a local immunosuppressive factor.

  7. Indoleamine 2,3 Dioxygenase (IDO Expression and Activity in Relapsing-Remitting Multiple Sclerosis.

    Directory of Open Access Journals (Sweden)

    Roberta Mancuso

    Full Text Available Interferon gamma (IFN-γ production induces the transcription of indoleamine 2,3 dioxygenase (IDO resulting in the reduction of T-cell activation and proliferation through the depletion of tryptophan and the elicitation of Treg lymphocytes. IDO was shown to be involved in the pathogenesis of autoimmune diseases; we investigated whether changes in IDO gene expression and activity could be indicative of onset of relapse in multiple sclerosis (MS patients.IDO and interferon-γ (IFN-γ gene expression, serum IDO activity (Kynurenine/Tryptophan ratio and serum neopterin concentration--a protein released by macrophages upon IFN-γ stimulation--were measured in 51 individuals: 36 relapsing remitting (RR-MS patients (21 in acute phase--AMS, 15 in stable phase--SMS and 15 healthy controls (HC. PBMCs samples in AMS patients were collected before (BT-AMS and during glucocorticoids-based therapy (DT-AMS.IDO expression was increased and IFN-γ was decreased (p<0.001 in BT-AMS compared to SMS patients. Glucocorticoids-induced disease remission resulted in a significant reduction of IDO and IFN-γ gene expression, IDO catalytic activity (p<0.001. Serum neopterin concentration followed the same trend as IDO expression and activity.Measurement of IDO gene expression and activity in blood could be a useful marker to monitor the clinical course of RR-MS. Therapeutic interventions modulating IDO activity may be beneficial in MS.

  8. Identification and expression pattern of a new carotenoid cleavage dioxygenase gene member from Bixa orellana.

    Science.gov (United States)

    Rodríguez-Ávila, N L; Narváez-Zapata, J A; Ramírez-Benítez, J E; Aguilar-Espinosa, M L; Rivera-Madrid, R

    2011-11-01

    Carotenoid cleavage dioxygenases (CCDs) are a class of enzymes involved in the biosynthesis of a broad diversity of secondary metabolites known as apocarotenoids. In plants, CCDs are part of a genetic family with members which cleave specific double bonds of carotenoid molecules. CCDs are involved in the production of diverse and important metabolites such as vitamin A and abscisic acid (ABA). Bixa orellana L. is the main source of the natural pigment annatto or bixin, an apocarotenoid accumulated in large quantities in its seeds. Bixin biosynthesis has been studied and the involvement of a CCD has been confirmed in vitro. However, the CCD genes involved in the biosynthesis of the wide variety of apocarotenoids found in this plant have not been well documented. In this study, a new CCD1 gene member (BoCCD1) was identified and its expression was charaterized in different plant tissues of B. orellana plantlets and adult plants. The BoCCD1 sequence showed high homology with plant CCD1s involved mainly in the cleavage of carotenoids in several sites to generate multiple apocarotenoid products. Here, the expression profiles of the BoCCD1 gene were analysed and discussed in relation to total carotenoids and other important apocarotenoids such as bixin. PMID:21813796

  9. Reaction mechanism of cobalt-substituted homoprotocatechuate 2,3-dioxygenase: a QM/MM study.

    Science.gov (United States)

    Cao, Lili; Dong, Geng; Lai, Wenzhen

    2015-04-01

    The reaction mechanisms of cobalt-substituted homoprotocatechuate 2,3-dioxygenase (Co-HPCD) with electron-rich substrate homoprotocatechuate (HPCA) and electron-poor substrate 4-nitrocatechol (4NC) were investigated by quantum mechanical/molecular mechanical (QM/MM) calculations. Our results demonstrated that the Co-O2 adducts has doublet ground state with a Co(III)-O2(•-) character when 4NC was used as the substrate, in good agreement with the EPR spectroscopic experiment. The reactive oxygen species is the doublet Co(III)-O2(•-) for Co-HPCD/4NC and the quartet SQ(•↑)-Co(II)-O2(•-↓) species for Co-HPCD/HPCA, indicating that the substrate plays important roles in the dioxygen activation by Co-HPCD. B3LYP was found to overestimate the rate-limiting barriers in Co-HPCD. TPSSh predicts barriers of 21.5 versus 12.0 kcal/mol for Co-HPCD/4NC versus Co-HPCD/HPCA, which is consistent with the fact that the rate of the reaction is decreased when the substrate was changed from HPCA to 4NC.

  10. Antiparasitic and antiproliferative effects of indoleamine 2,3-dioxygenase enzyme expression in human fibroblasts.

    Science.gov (United States)

    Gupta, S L; Carlin, J M; Pyati, P; Dai, W; Pfefferkorn, E R; Murphy, M J

    1994-01-01

    Studies were carried out to evaluate the proposed role of indoleamine 2,3-dioxygenase (INDO) induction in the antimicrobial and antiproliferative effects of gamma interferon (IFN-gamma) in human fibroblasts. The INDO cDNA coding region was cloned in the pMEP4 expression vector, containing the metallothionein (MTII) promoter in the sense (+ve) or the antisense (-ve) orientation. Human fibroblasts (GM637) stably transfected with the sense construct expressed INDO activity after treatment with CdCl2 or ZnSO4, but cells transfected with the antisense construct did not. The growth of Chlamydia psittaci was strongly inhibited in INDO +ve cells but not in INDO -ve cells after treatment with Cd2+ or Zn2+. The inhibition correlated with the level of INDO activity induced and could be reversed by the addition of excess tryptophan to the medium. The growth of Toxoplasma gondii was also strongly inhibited in INDO +ve cells but not in INDO -ve cells after treatment with Cd2+. Expression of Cd(2+)-induced INDO activity also inhibited thymidine incorporation and led to cytotoxicity in INDO +ve cells but not in INDO -ve cells. Thus, the induction of INDO activity by IFN-gamma may be an important factor in the antimicrobial and antiproliferative effects of IFN-gamma in human fibroblasts. Images PMID:8188349

  11. Cysteine dioxygenase type 1 promotes adipogenesis via interaction with peroxisome proliferator-activated receptor gamma

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Peng; Chen, Yi; Ji, Ning; Lin, Yunfeng; Yuan, Quan; Ye, Ling; Chen, Qianming, E-mail: qmchen@scu.edu.cn

    2015-02-27

    Mammalian cysteine dioxygenase type 1 (CDO1) is an essential enzyme for taurine biosynthesis and the biodegradation of toxic cysteine. As previously suggested, Cdo1 may be a marker of liposarcoma progression and adipogenic differentiation, but the role of Cdo1 in adipogenesis has yet been reported. In this study, we found that the expression of Cdo1 is dramatically elevated during adipogenic differentiation of 3T3-L1 pre-adipocytes and mouse bone marrow-derived mesenchymal stem cells (mBMSCs). Conversely, knockdown of Cdo1 inhibited expression of adipogenic specific genes and lipid droplet formation in 3T3-L1 cells and mBMSCs. Mechanistically, we found Cdo1 interacted with Pparγ in response to adipogenic stimulus. Further, depletion of Cdo1 reduced the recruitment of Pparγ to the promoters of C/EBPα and Fabp4. Collectively, our finding indicates that Cdo1 may be a co-activator of Pparγ in adipogenesis, and may contribute to the development of disease associated with excessive adipose tissue. - Highlights: • Cdo1expression is highly up-regulated during adipogenic differentiation of 3T3-L1 and mBMSCs. • Depletion of Cdo1 inhibited expression of adipogenic specific genes and lipid droplet formation. • Cdo1interacts with Pparγ during adipogenesis. • Knockdown of Cdo1 inhibited Pparγ binding to the promoters of C/EBPα and Fabp4.

  12. Indoleamine 2,3-dioxygenase expression in patients with allergic rhinitis: a case-control study

    Directory of Open Access Journals (Sweden)

    Luukkainen Annika

    2011-12-01

    Full Text Available Abstract Background Indoleamine 2,3-dioxygenase (IDO is a tryptophan catalyzing enzyme. It has been suggested that it has a role in lower airway allergic inflammations, but its role in allergic rhinitis has not been investigated. Objective Our aim was to evaluate the expression of IDO in the nasal mucosa of allergic rhinitis patients allergic to birch pollen during peak exposure to birch pollen allergen and compare it to non-atopic patients. Methods IDO expression was immunohistochemically evaluated from nasal specimens obtained in- and off-season from otherwise healthy non-smoking volunteers both allergic to birch pollen (having mild or moderate allergic rhinoconjunctivitis and non-allergic controls. Results: The IDO expression levels were low in healthy controls and remained low also in patients allergic to birch pollen. There were no differences in the expression of IDO in- and off-season in either healthy or allergic subjects. Conclusions There is a controversy in the role of IDO in upper and lower airways during allergic airway disease. It seems that IDO is associated to allergic inflammations of the lower airways, but does not have a local role in the nasal cavity at least in mild or moderate forms of allergic rhinitis.

  13. Tissue distribution, intracellular localization and proteolytic processing of rat 4-hydroxyphenylpyruvate dioxygenase.

    Science.gov (United States)

    Neve, Søren; Aarenstrup, Lene; Tornehave, Ditte; Rahbek-Nielsen, Henrik; Corydon, Thomas Juhl; Roepstorff, Peter; Kristiansen, Karsten

    2003-01-01

    4-hydroxyphenylpyruvate dioxygenase (HPD) is an important enzyme involved in tyrosine catabolism. HPD was shown to be identical to a protein named the F-antigen, exploited by immunologists because of its unique immunological properties. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. Decreased expression of HPD is often observed in association with the severe type I tyrosinemia, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. In this study we present a comprehensive analysis of tissue specific expression and intracellular localization of HPD in the rat. By combined use of in situ hybridization and immunohistochemistry we confirm previously known sites of expression in liver and kidney. In addition, we show that HPD is abundantly expressed in neurons in the cortex, cerebellum and hippocampus. By using immunoelectron microscopy and confocal laser scanning microscopy, we provide evidence that HPD contrary to earlier assumptions specifically localizes to membranes of the endoplasmic reticulum and the Golgi apparatus. Detailed mass spectrometric analyses of HPD purified from rat liver revealed N-terminal and C-terminal processing of HPD, and expression of recombinant HPD suggested that C-terminal processing enhances the enzymatic activity.

  14. Expression and post-translational modification of human 4-hydroxy-phenylpyruvate dioxygenase.

    Science.gov (United States)

    Aarenstrup, Lene; Falch, Anne Marie; Jakobsen, Kirsten K; Neve, Søren; Henriksen L, Linda Ø; Tommerup, Niels; Leffers, Henrik; Kristiansen, Karsten

    2002-01-01

    4-hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. The HPD gene was previously mapped to the chromosomal region 12q24-->qter. In the present study high-resolution chromosome mapping localized the HPD gene to 12q24.31. DNase I footprinting, revealed that four regions of the HPD promoter were protected by rat liver nuclear proteins. Computer-assisted analyses suggested that these elements might bind Sp1/AP2, HNF4, HNF3/CREB, and C/EBP, respectively. In transient transfection experiments, the proximal 271bp of the promoter conferred basal transcriptional activation in human Chang cells. Sequences in intron 1 were able to enhance the activity of this basal promoter. Finally, vaccinia virus-based expression provided evidence that HPD is subject to phosphorylation, and furthermore, allowed mapping of the HPD protein in the human keratinocyte 2D database.

  15. Mutations in the 4-hydroxyphenylpyruvic acid dioxygenase gene are responsible for tyrosinemia type III and hawkinsinuria.

    Science.gov (United States)

    Tomoeda, K; Awata, H; Matsuura, T; Matsuda, I; Ploechl, E; Milovac, T; Boneh, A; Scott, C R; Danks, D M; Endo, F

    2000-11-01

    The enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) catalyzes the reaction of 4-hydroxyphenylpyruvic acid to homogentisic acid in the tyrosine catabolism pathway. A deficiency in the catalytic activity of HPD may lead to tyrosinemia type III, an autosomal recessive disorder characterized by elevated levels of blood tyrosine and massive excretion of tyrosine derivatives into urine. It has been postulated that hawkinsinuria, an autosomal dominant disorder characterized by the excretion of 'hawkinsin,' may also be a result of HPD deficiency. Hawkinsin is a sulfur amino acid identified as (2-l-cystein-S-yl, 4-dihydroxycyclohex-5-en-1-yl)acetic acid. Patients with hawkinsinuria excrete this metabolite in their urine throughout their life, although symptoms of metabolic acidosis and tyrosinemia improve in the first year of life. We performed analyses of the HPD gene in a patient with tyrosinemia type III and two unrelated patients with hawkinsinuria. A homozygous missense mutation predicting an Ala to Val change at codon 268 (A268V) in the HPD gene was found in the patient with tyrosinemia type III. A heterozygous missense mutation predicting an Ala to Thr change at codon 33 (A33T) was found in the same HPD gene in the two patients with hawkinsinuria. These findings support the hypothesis that alterations in the structure and activity of HPD are causally related to two different metabolic disorders, tyrosinemia type III and hawkinsinuria.

  16. Emerging concepts on inhibitors of indoleamine 2,3-dioxygenase in rheumatic diseases.

    Science.gov (United States)

    Filippini, P; Del Papa, N; Sambataro, D; Del Bufalo, A; Locatelli, F; Rutella, S

    2012-01-01

    The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) finely regulates both innate and adaptive immune responses through the degradation of the essential amino acid tryptophan into kynurenine and other downstream metabolites, which suppress effector T-cell function and promote the differentiation of regulatory T cells. A novel role for IDO1 as a signaling molecule and a modifier of innate inflammatory responses is now emerging. In particular, IDO1 can either support or antagonize inflammation in a context- and tissuedependent manner. Studies in experimental arthritis have unravelled a previously unappreciated role for IDO in controlling B-cell activation and autoantibody production. IDO dysregulation has been documented in patients with systemic lupus erythematosus, systemic sclerosis and Sjogren's syndrome, as well as in severe sepsis and chronic kidney disease. This article summarizes the contribution of IDO to the pathophysiology of inflammatory/autoimmune disorders, and discusses whether strategies to restore metabolic equilibrium in the kynurenine pathway might be pursued in diseases states such as rheumatoid arthritis and systemic sclerosis. PMID:22963664

  17. The Role of Indoleamine 2, 3-Dioxygenase in Immune Suppression and Autoimmunity

    Directory of Open Access Journals (Sweden)

    Jacques C. Mbongue

    2015-09-01

    Full Text Available Indoleamine 2, 3-dioxygenase (IDO is the first and rate limiting catabolic enzyme in the degradation pathway of the essential amino acid tryptophan. By cleaving the aromatic indole ring of tryptophan, IDO initiates the production of a variety of tryptophan degradation products called “kynurenines” that are known to exert important immuno-regulatory functions. Because tryptophan must be supplied in the diet, regulation of tryptophan catabolism may exert profound effects by activating or inhibiting metabolism and immune responses. Important for survival, the regulation of IDO biosynthesis and its activity in cells of the immune system can critically alter their responses to immunological insults, such as infection, autoimmunity and cancer. In this review, we assess how IDO-mediated catabolism of tryptophan can modulate the immune system to arrest inflammation, suppress immunity to cancer and inhibit allergy, autoimmunity and the rejection of transplanted tissues. Finally, we examine how vaccines may enhance immune suppression of autoimmunity through the upregulation of IDO biosynthesis in human dendritic cells.

  18. Indoleamine 2, 3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

    Institute of Scientific and Technical Information of China (English)

    Shih Ling HWANG; Nancy Pei-Yee CHUNG; Jacqueline Kwai-Yi CHAN; Chen-Lung Steve LIN

    2005-01-01

    Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs),and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC functions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflammatory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regulated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

  19. Expression Profile of Carotenoid Cleavage Dioxygenase Genes in Summer Squash (Cucurbita pepo L.).

    Science.gov (United States)

    González-Verdejo, Clara I; Obrero, Ángeles; Román, Belén; Gómez, Pedro

    2015-06-01

    Carotenoids are important dietary components that can be found in vegetable crops. The accumulation of these compounds in fruit and vegetables is altered by the activity of carotenoid cleavage dioxygenases (CCDs) enzymes that produce their degradation. The aim of this work was to study the possible implication of CCD genes in preventing carotenoid storage in the horticultural crop summer squash (Cucurbita pepo L.). The relationship between the presence of these compounds and gene expression for CCDs was studied in three varieties showing different peel and flesh colour. Expression analysis for the CCD genes CpNCED1, CpNCED2, CpNCED3, CpNCED9, CpCCD1, CpCCD4a, CpCCD4b and CpCCD8 was carried out on different organs and at several fruit developmental stages. The results showed that the CpCCD4a and CpCCD4b genes were highly expressed in the variety with lowest carotenoid content suggesting a putative role in carotenoid accumulation pattern in summer squash fruit.

  20. Substrate Recognition and Catalysis by the Cofactor-Independent Dioxygenase DpgC+

    Energy Technology Data Exchange (ETDEWEB)

    Fielding,E.; Widboom, P.; Bruner, S.

    2007-01-01

    The enzyme DpgC belongs to a small class of oxygenases not dependent on accessory cofactors for activity. DpgC is in the biosynthetic pathway for the nonproteinogenic amino acid 3, 5-dihydroxyphenylglycine in actinomycetes bacteria responsible for the production of the vancomycin/teicoplanin family of antibiotic natural products. The X-ray structure of DpgC confirmed the absence of cofactors and defined a novel hydrophobic dioxygen binding pocket adjacent to a bound substrate analogue. In this paper, the role specific amino acids play in substrate recognition and catalysis is examined through biochemical and structural characterization of site-specific enzyme mutations and alternate substrates. The results establish the importance of three amino acids, Arg254, Glu299, and Glu189, in the chemistry of DpgC. Arg254 and Glu189 join to form a specific contact with one of the phenolic hydroxyls of the substrate, and this interaction plays a key role in both substrate recognition and catalysis. The X-ray crystal structure of Arg254Lys was determined to address the role this residue plays in the chemistry. In addition, characterization of alternate substrate analogues demonstrates the presence and position of phenol groups are necessary for both enzyme recognition and downstream oxidation chemistry. Overall, this work defines the mechanism of substrate recognition and specificity by the cofactor-independent dioxygenase DpgC.

  1. Tropomyosin-binding properties modulate competition between tropomodulin isoforms.

    Science.gov (United States)

    Colpan, Mert; Moroz, Natalia A; Gray, Kevin T; Cooper, Dillon A; Diaz, Christian A; Kostyukova, Alla S

    2016-06-15

    The formation and fine-tuning of cytoskeleton in cells are governed by proteins that influence actin filament dynamics. Tropomodulin (Tmod) regulates the length of actin filaments by capping the pointed ends in a tropomyosin (TM)-dependent manner. Tmod1, Tmod2 and Tmod3 are associated with the cytoskeleton of non-muscle cells and their expression has distinct consequences on cell morphology. To understand the molecular basis of differences in the function and localization of Tmod isoforms in a cell, we compared the actin filament-binding abilities of Tmod1, Tmod2 and Tmod3 in the presence of Tpm3.1, a non-muscle TM isoform. Tmod3 displayed preferential binding to actin filaments when competing with other isoforms. Mutating the second or both TM-binding sites of Tmod3 destroyed its preferential binding. Our findings clarify how Tmod1, Tmod2 and Tmod3 compete for binding actin filaments. Different binding mechanisms and strengths of Tmod isoforms for Tpm3.1 contribute to their divergent functional capabilities.

  2. Bacteria-Induced Dscam Isoforms of the Crustacean, Pacifastacus leniusculus.

    Directory of Open Access Journals (Sweden)

    Apiruck Watthanasurorot

    2011-06-01

    Full Text Available The Down syndrome cell adhesion molecule, also known as Dscam, is a member of the immunoglobulin super family. Dscam plays an essential function in neuronal wiring and appears to be involved in innate immune reactions in insects. The deduced amino acid sequence of Dscam in the crustacean Pacifastacus leniusculus (PlDscam, encodes 9(Ig-4(FNIII-(Ig-2(FNIII-TM and it has variable regions in the N-terminal half of Ig2 and Ig3 and the complete Ig7 and in the transmembrane domain. The cytoplasmic tail can generate multiple isoforms. PlDscam can generate more than 22,000 different unique isoforms. Bacteria and LPS injection enhanced the expression of PlDscam, but no response in expression occurred after a white spot syndrome virus (WSSV infection or injection with peptidoglycans. Furthermore, PlDscam silencing did not have any effect on the replication of the WSSV. Bacterial specific isoforms of PlDscam were shown to have a specific binding property to each tested bacteria, E. coli or S. aureus. The bacteria specific isoforms of PlDscam were shown to be associated with bacterial clearance and phagocytosis in crayfish.

  3. Role of p53 isoforms and aggregations in cancer.

    Science.gov (United States)

    Kim, SeJin; An, Seong Soo A

    2016-06-01

    p53 is a master regulatory protein that is involved in diverse cellular metabolic processes such as apoptosis, DNA repair, and cell cycle arrest. The protective function of p53 (in its homotetrameric form) as a tumor suppressor is lost in more than 50% of human cancers.Despite considerable experimental evidence suggesting the presence of multiple p53 states, it has been difficult to correlate the status of p53 with cancer response to treatments and clinical outcomes, which suggest the importance of complex but essential p53 regulatory pathways.Recent studies have indicated that the expression pattern of p53 isoforms may play a crucial role in regulating normal and cancer cell fates in response to diverse stresses. The human TP53 gene encodes at least 12 p53 isoforms, which are produced in normal tissue through alternative initiation of translation, usage of alternative promoters, and alternative splicing. Furthermore, some researchers have suggested that the formation of mutant p53 aggregates may be associated with cancer pathogenesis due to loss-of function (LoF), dominant-negative (DN), and gain-of function (GoF) effects.As different isoforms or the aggregation state of p53 may influence tumorigenesis, this review aims to examine the correlation of p53 isoforms and aggregation with cancer. PMID:27368003

  4. Identification and characterization of a novel isoform of hepatopoietin

    Institute of Scientific and Technical Information of China (English)

    Jun Lu; Wang-Xiang Xu; Yi-Qun Zhan; Xiao-Lin Cui; Wei-Min Cai; Fu-Chu He; Xiao-Ming Yang

    2002-01-01

    AIM: To isolate a novel isoform of human HPO (HPO-205)human fetal liver Marathon-reedy cDNA andcharacterize its primary biological function.METHODS: 5'-RACE (rapid amplification of cDNA 5' ends)was used to isolate a novel isoform of hHPO in this paperThe constructed pcDNAHPO-205, pcDNAHPO and pcDNA eukaryotic expression vectors were respectively transfectedby lipofectamine method and the stimulation of DNAsynthesis was observed by 3H-TdR incorporation assay.Proteins extracted from different cells were analyzed byWestern blot.RESULTS: A novel isoform of hHPO (HPO-205) encoding a205 amino acid ORF corresponding to a translatedproduction of 23 kDa was isolated and distinguished fromthe previous HPO that lacked the N-terminal 80 amino acids.The dnse-dspendent stimulation of DNA synthesis of HepG2hepatoma cells by HPO-205 demonstrated its similarbiological activity with HPO in vitro. The level of MAPK(Mitogen-activated protein kinase) phnsphorylarion byWestern blot analysis revealed that HPO-205 might have thestronger activity of stimulating hepatic cell proliferation thanthat of HPO.CONCLUSION: A novel isoform of hHPO (HPO-205) wasisolated from hepatic-derived cells. The comparison of HPO-205 and HPO will lead to a new insight into the structure andfunction of hHPO, and provide the new way of thinking todeeply elucidate the biological roles of HPO/ALR.

  5. Distinct Functions of Endophilin Isoforms in Synaptic Vesicle Endocytosis

    Directory of Open Access Journals (Sweden)

    Jifeng Zhang

    2015-01-01

    Full Text Available Endophilin isoforms perform distinct characteristics in their interactions with N-type Ca2+ channels and dynamin. However, precise functional differences for the endophilin isoforms on synaptic vesicle (SV endocytosis remain unknown. By coupling RNA interference and electrophysiological recording techniques in cultured rat hippocampal neurons, we investigated the functional differences of three isoforms of endophilin in SV endocytosis. The results showed that the amplitude of normalized evoked excitatory postsynaptic currents in endophilin1 knockdown neurons decreased significantly for both single train and multiple train stimulations. Similar results were found using endophilin2 knockdown neurons, whereas endophilin3 siRNA exhibited no change compared with control neurons. Endophilin1 and endophilin2 affected SV endocytosis, but the effect of endophilin1 and endophilin2 double knockdown was not different from that of either knockdown alone. This result suggested that endophilin1 and endophilin2 functioned together but not independently during SV endocytosis. Taken together, our results indicate that SV endocytosis is sustained by endophilin1 and endophilin2 isoforms, but not by endophilin3, in primary cultured hippocampal neurons.

  6. Isoforms of transferrin in psoriasis patients abusing alcohol

    NARCIS (Netherlands)

    P. Hoefkens (Peter); E.M. Higgins; R.J. Ward (Roberta); H.G. van Eijk (Henk)

    1997-01-01

    textabstractThe different isoforms of transferrin have been quantified by isoelectric focusing in the sera of psoriasis patients with and without a history of abusing alcohol. In both male and female psoriasis subjects abusing alcohol, there were significant increases in the 2-sial

  7. Tropomyosin-binding properties modulate competition between tropomodulin isoforms.

    Science.gov (United States)

    Colpan, Mert; Moroz, Natalia A; Gray, Kevin T; Cooper, Dillon A; Diaz, Christian A; Kostyukova, Alla S

    2016-06-15

    The formation and fine-tuning of cytoskeleton in cells are governed by proteins that influence actin filament dynamics. Tropomodulin (Tmod) regulates the length of actin filaments by capping the pointed ends in a tropomyosin (TM)-dependent manner. Tmod1, Tmod2 and Tmod3 are associated with the cytoskeleton of non-muscle cells and their expression has distinct consequences on cell morphology. To understand the molecular basis of differences in the function and localization of Tmod isoforms in a cell, we compared the actin filament-binding abilities of Tmod1, Tmod2 and Tmod3 in the presence of Tpm3.1, a non-muscle TM isoform. Tmod3 displayed preferential binding to actin filaments when competing with other isoforms. Mutating the second or both TM-binding sites of Tmod3 destroyed its preferential binding. Our findings clarify how Tmod1, Tmod2 and Tmod3 compete for binding actin filaments. Different binding mechanisms and strengths of Tmod isoforms for Tpm3.1 contribute to their divergent functional capabilities. PMID:27091317

  8. Cloning, expression and alternative splicing of the novel isoform of hTCP11 gene

    DEFF Research Database (Denmark)

    Ma, Yong-xin; Zhang, Si-zhong; Wu, Qia-qing;

    2003-01-01

    To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing.......To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing....

  9. Growth hormone isoforms in a girl with gigantism.

    Science.gov (United States)

    Ng, L L; Chasalow, F I; Escobar, O; Blethen, S L

    1999-01-01

    Several previous investigations have suggested that there may be different growth hormone isoforms in patients with acromegaly. We used three different site-specific monoclonal antibodies (MAbs) to investigate growth hormone (GH) isoforms in serum from an 8 year-old girl with a GH and prolactin secreting adenoma. The pattern of GH-immunoreactivity was dependent on the circumstances of collection. Serum obtained after oral glucose had very little cross reactivity with MAb 352 although concentrations of up to 15 micrograms/l were found with two other MAbs, 033 and 665. MAb 352 does not recognize the 20,000 dalton isoform of GH (20K) while both MAb 033 and 665 do. The same pattern of GH immunoreactivity (low MAb 352, equal and higher MAb 033 and 665) was seen in other baseline samples. In contrast, samples obtained after TRH/GnRH showed immunoreactivity patterns expected for a mixture of 22,000 dalton isoform of GH (22K) with only a small amount of 20K. GH samples obtained during sleep showed both patterns with episodic peaks with equal immunoreactivity superimposed on the basal pattern (decreased activity with MAb 352). Affinity chromatography of basal samples showed that a portion of the GH immunoreactivity was neither 22K nor 20K, although in stimulated samples, over 70% of GH was 22K or 20K GH. In conclusion, the nature of GH isoforms present in serum varies with GH concentration. These differences may contribute to the known difficulty in correlating disease activity and random GH measurements in patients with GH secreting adenomas. PMID:10392356

  10. Determination of the class and isoform selectivity of small-molecule histone deacetylase inhibitors

    DEFF Research Database (Denmark)

    Khan, N.; Jeffers, M.; Kumar, S.;

    2008-01-01

    ) against a panel of rhHDAC (recombinant human HDAC) isoforms. Eight rhHDACs were expressed using a baculoviral system, and a Fluor de Lystrade mark (Biomol International) HDAC assay was optimized for each purified isoform. The potency and selectivity of ten HDACs on class I isoforms (rhHDAC1, rhHDAC2, rh...

  11. Expression, purification and enzymatic characterization of the catalytic domains of human tryptophan hydroxylase isoforms

    DEFF Research Database (Denmark)

    Windahl, Michael Skovbo; Boesen, Jane; Karlsen, Pernille Efferbach;

    2009-01-01

    Tryptophan hydroxylase exists in two isoforms: Isoform 1 catalyses the first and rate-limiting step in the synthesis of serotonin in the peripheral parts of the body while isoform 2 catalyses this step in the brain. The catalytic domains of human tryptophan hydroxylase 1 and 2 have been expressed...

  12. Functional analysis of the copper-dependent quercetin 2,3-dioxygenase. 2. X-ray absorption studies of native enzyme and anaerobic complexes with the substrates quercetin and myricetin

    NARCIS (Netherlands)

    Steiner, Roberto A.; Meyer-Klaucke, Wolfram; Dijkstra, Bauke W.

    2002-01-01

    Quercetin 2,3-dioxygenase (2,3QD) is a mononuclear copper-dependent dioxygenase which catalyzes the cleavage of the heterocyclic ring of the flavonol quercetin (5,7,3',4'-tetrahydroxy flavonol) to produce 2-protocatechuoyl-phloroglucinol carboxylic acid and carbon monoxide. In this study, X-ray abso

  13. A nonsense mutation in the 4-hydroxyphenylpyruvic acid dioxygenase gene (Hpd) causes skipping of the constitutive exon and hypertyrosinemia in mouse strain III

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Fumio; Awata, Hisataka; Matsuda, Ichiro [Kumamoto Univ. (Japan)

    1995-01-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD; EC 1.13.11.27) is an important enzyme in tyrosine catabolism in most organisms. Decreased activity of 4-hydroxyphenylpyruvic acid dioxygenase in the liver of mouse strain III is associated with tyrosinemia. We report a nucleotide substitution that generates a termination codon in exon 7 of the 4-hydroxyphenylpyruvic acid dioxygenase gene in III mice. This mutation is associated with partial exon skipping, and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Mouse strain III is a model for human tyrosinemia type 3 (McKusick 276710), and this train together with recently established models for tyrosinemia type 1 will facilitate studies of hereditary tyrosinemias.

  14. A nonsense mutation in the 4-hydroxyphenylpyruvic acid dioxygenase gene (Hpd) causes skipping of the constitutive exon and hypertyrosinemia in mouse strain III.

    Science.gov (United States)

    Endo, F; Awata, H; Katoh, H; Matsuda, I

    1995-01-01

    4-Hydroxyphenylpyruvic acid dioxygenase (HPD; EC 1.13.11.27) is an important enzyme in tyrosine catabolism in most organisms. Decreased activity of 4-hydroxyphenylpyruvic acid dioxygenase in the liver of mouse strain III is associated with tyrosinemia. We report a nucleotide substitution that generates a termination codon in exon 7 of the 4-hydroxyphenylpyruvic acid dioxygenase gene in III mice. This mutation is associated with partial exon skipping, and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Mouse strain III is a model for human tyrosinemia type 3 (McKusick 276710), and this strain together with recently established models for tyrosinemia type 1 will facilitate studies of hereditary tyrosinemias.

  15. One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A.; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A., E-mail: roberto.perego@unimib.it

    2013-08-01

    The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness. -Highlights: • Each of the eight Arg isoforms was transfected in COS-7 cells. • Only the 1BSCTS Arg isoform has a nuclear distribution in transfected cells. • The cytoplasmic isoforms and F-actin colocalize cortically and in cell protrusions. • Arg isoforms differently phosphorylate p190RhoGAP and CrkII. • Arg isoforms differently modulate stress fibers, cell protrusions and motility.

  16. EGFR soluble isoforms and their transcripts are expressed in meningiomas.

    Science.gov (United States)

    Guillaudeau, Angélique; Durand, Karine; Bessette, Barbara; Chaunavel, Alain; Pommepuy, Isabelle; Projetti, Fabrice; Robert, Sandrine; Caire, François; Rabinovitch-Chable, Hélène; Labrousse, François

    2012-01-01

    The EGFR (epidermal growth factor receptor) is involved in the oncogenesis of many tumors. In addition to the full-length EGFR (isoform a), normal and tumor cells produce soluble EGFR isoforms (sEGFR) that lack the intracellular domain. sEGFR isoforms b, c and d are encoded by EGFR variants 2 (v2), 3 (v3) and 4 (v4) mRNA resulting from gene alternative splicing. Accordingly, the results of EGFR protein expression analysis depend on the domain targeted by the antibodies. In meningiomas, EGFR expression investigations mainly focused on EGFR isoform a. sEGFR and EGFRvIII mutant, that encodes a constitutively active truncated receptor, have not been studied. In a 69 meningiomas series, protein expression was analyzed by immunohistochemistry using extracellular domain targeted antibody (ECD-Ab) and intracellular domain targeted antibody (ICD-Ab). EGFRv1 to v4 and EGFRvIII mRNAs were quantified by RT-PCR and EGFR amplification revealed by MLPA. Results were analyzed with respect to clinical data, tumor resection (Simpson grade), histological type, tumor grade, and patient outcome.Immunochemical staining was stronger with ECD-Ab than with ICD-Ab. Meningiomas expressed EGFRv1 to -v4 mRNAs but not EGFRvIII mutant. Intermediate or high ECD-Ab staining and high EGFRv1 to v4 mRNA levels were associated to a better progression free survival (PFS). PFS was also improved in women, when tumor resection was evaluated as Simpson 1 or 2, in grade I vs. grade II and III meningiomas and when Ki67 labeling index was lower than 10%. Our results suggest that, EGFR protein isoforms without ICD and their corresponding mRNA variants are expressed in meningiomas in addition to the whole isoform a. EGFRvIII was not expressed. High expression levels seem to be related to a better prognosis. These results indicate that the oncogenetic mechanisms involving the EGFR pathway in meningiomas could be different from other tumor types. PMID:22623992

  17. EGFR soluble isoforms and their transcripts are expressed in meningiomas.

    Directory of Open Access Journals (Sweden)

    Angélique Guillaudeau

    Full Text Available The EGFR (epidermal growth factor receptor is involved in the oncogenesis of many tumors. In addition to the full-length EGFR (isoform a, normal and tumor cells produce soluble EGFR isoforms (sEGFR that lack the intracellular domain. sEGFR isoforms b, c and d are encoded by EGFR variants 2 (v2, 3 (v3 and 4 (v4 mRNA resulting from gene alternative splicing. Accordingly, the results of EGFR protein expression analysis depend on the domain targeted by the antibodies. In meningiomas, EGFR expression investigations mainly focused on EGFR isoform a. sEGFR and EGFRvIII mutant, that encodes a constitutively active truncated receptor, have not been studied. In a 69 meningiomas series, protein expression was analyzed by immunohistochemistry using extracellular domain targeted antibody (ECD-Ab and intracellular domain targeted antibody (ICD-Ab. EGFRv1 to v4 and EGFRvIII mRNAs were quantified by RT-PCR and EGFR amplification revealed by MLPA. Results were analyzed with respect to clinical data, tumor resection (Simpson grade, histological type, tumor grade, and patient outcome.Immunochemical staining was stronger with ECD-Ab than with ICD-Ab. Meningiomas expressed EGFRv1 to -v4 mRNAs but not EGFRvIII mutant. Intermediate or high ECD-Ab staining and high EGFRv1 to v4 mRNA levels were associated to a better progression free survival (PFS. PFS was also improved in women, when tumor resection was evaluated as Simpson 1 or 2, in grade I vs. grade II and III meningiomas and when Ki67 labeling index was lower than 10%. Our results suggest that, EGFR protein isoforms without ICD and their corresponding mRNA variants are expressed in meningiomas in addition to the whole isoform a. EGFRvIII was not expressed. High expression levels seem to be related to a better prognosis. These results indicate that the oncogenetic mechanisms involving the EGFR pathway in meningiomas could be different from other tumor types.

  18. An EXAFS study of the interaction of substrate with the ferric active site of protocatechuate 3,4-dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    True, A.E.; Orville, A.M.; Pearce, L.L.; Lipscomb, J.D.; Que, L. Jr. (Univ. of Minnesota, Minneapolis (USA))

    1990-12-01

    X-ray crystallographic studies of the intradiol cleaving protocatechuate 3,4-dioxygenase from Pseudomonas aeruginosa have shown that the enzyme has a trigonal bipyramidal ferric active site with two histidines, two tyrosines, and a solvent molecule as ligands. Fe K-edge EXAFS studies of the spectroscopically similar protocatechuate 3,4-dioxygenase from Brevibacterium fuscum are consistent with a pentacoordinate geometry of the iron active site with 3 O/N ligands at 1.90 {angstrom} and 2 O/N ligands at 2.08 {angstrom}. The 2.08-{angstrom} bonds are assigned to the two histidines, while the 1.90-{angstrom} bonds are associated with the two tyrosines and the coordinated solvent. The short Fe-O distance for the solvent suggests that it coordinates as hydroxide rather than water. When the inhibitor terephthalate is bound to the enzyme, the XANES data indicate that the ferric site becomes 6-coordinate and the EXAFS data show a beat pattern which can only be simulated with an additional Fe-O/N interaction at 2.46 {angstrom}. Together, the data suggest that the oxygens of the carboxylate group in terephthalate displace the hydroxide and chelate to the ferric site but in an asymmetric fashion. In contrast, protocatechuate 3,4-dioxygenase remains 5-coordinate upon the addition of the slow substrate homoprotocatechuic acid (HPCA). Previous EPR data have indicated that HPCA forms an iron chelate via the two hydroxyl functions. For the iron site to remain 5-coordinate and the HPCA to be chelated to the iron, the substrate must displace not only the hydroxide but also a ligand from the protein backbone, probably a histidine. The mechanistic implications of the displacement of hydroxide and a protein ligand in the active site are discussed.

  19. Swapping metals in Fe- and Mn-dependent dioxygenases: Evidence for oxygen activation without a change in metal redox state

    Energy Technology Data Exchange (ETDEWEB)

    Emerson, Joseph P.; Kovaleva, Elena G.; Farquhar, Erik R.; Lipscomb, John D.; Oue, Jr., Lawrence (UMM)

    2008-07-21

    Biological O{sub 2} activation often occurs after binding to a reduced metal [e.g., M(II)] in an enzyme active site. Subsequent M(II)-to-O{sub 2} electron transfer results in a reactive M(III)-superoxo species. For the extradiol aromatic ring-cleaving dioxygenases, we have proposed a different model where an electron is transferred from substrate to O{sub 2} via the M(II) center to which they are both bound, thereby obviating the need for an integral change in metal redox state. This model is tested by using homoprotocatechuate 2,3-dioxygenases from Brevibacterium fuscum (Fe-HPCD) and Arthrobacter globiformis (Mn-MndD) that share high sequence identity and very similar structures. Despite these similarities, Fe-HPCD binds Fe(II) whereas Mn-MndD incorporates Mn(II). Methods are described to incorporate the nonphysiological metal into each enzyme (Mn-HPCD and Fe-MndD). The x-ray crystal structure of Mn-HPCD at 1.7 {angstrom} is found to be indistinguishable from that of Fe-HPCD, while EPR studies show that the Mn(II) sites of Mn-MndD and Mn-HPCD, and the Fe(II) sites of the NO complexes of Fe-HPCD and Fe-MndD, are very similar. The uniform metal site structures of these enzymes suggest that extradiol dioxygenases cannot differentially compensate for the 0.7-V gap in the redox potentials of free iron and manganese. Nonetheless, all four enzymes exhibit nearly the same K{sub M} and V{sub max} values. These enzymes constitute an unusual pair of metallo-oxygenases that remain fully active after a metal swap, implicating a different way by which metals are used to promote oxygen activation without an integral change in metal redox state.

  20. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase

    International Nuclear Information System (INIS)

    Highlights: ► Regiospecificity of BphAERR41 toward dibenzofuran and 2-chlorodibenzofuran differs. ► We compared the structures of the substrate-bound forms of the enzyme with both substrates. ► Dibenzofuran is compelled to move during the catalytic reaction. ► Ser283 contact with 2-chlorodibenzofuran helps prevent substrate movement during the reaction. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAELB400) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAELB400 and obtained BphAERR41. This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAELB400. However, the regiospecificity of BphAERR41 toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAERR41 obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAERR41:dibenzofuran. In BphAERR41:2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAERR41:dibenzofuran, and strong enough in the BphAERR41:2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.

  1. Structural insights into the metabolism of 2-chlorodibenzofuran by an evolved biphenyl dioxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pravindra [Department of Biological Sciences and Center for Cancer Research, Purdue University, West Lafayette, IN 47907 (United States); Department of Biotechnology, Indian Institute of Technology, Roorkee 247667 (India); Mohammadi, Mahmood [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada); Dhindwal, Sonali [Department of Biotechnology, Indian Institute of Technology, Roorkee 247667 (India); Pham, Thi Thanh My [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada); Bolin, Jeffrey T. [Department of Biological Sciences and Center for Cancer Research, Purdue University, West Lafayette, IN 47907 (United States); Sylvestre, Michel, E-mail: Michel.Sylvestre@iaf.inrs.ca [Institut National de la Recherche Scientifique (INRS-Institut Armand-Frappier), Laval, QC, Canada H7V 1B7 (Canada)

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer Regiospecificity of BphAE{sub RR41} toward dibenzofuran and 2-chlorodibenzofuran differs. Black-Right-Pointing-Pointer We compared the structures of the substrate-bound forms of the enzyme with both substrates. Black-Right-Pointing-Pointer Dibenzofuran is compelled to move during the catalytic reaction. Black-Right-Pointing-Pointer Ser283 contact with 2-chlorodibenzofuran helps prevent substrate movement during the reaction. -- Abstract: The biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE{sub LB400}) is a Rieske-type oxygenase that catalyzes the stereospecific oxygenation of many heterocyclic aromatics including dibenzofuran. In a previous work, we evolved BphAE{sub LB400} and obtained BphAE{sub RR41}. This variant metabolizes dibenzofuran and 2-chlorodibenzofuran more efficiently than BphAE{sub LB400}. However, the regiospecificity of BphAE{sub RR41} toward these substrates differs. Dibenzofuran is metabolized principally through a lateral dioxygenation whereas 2-chlorodibenzofuran is metabolized principally through an angular dioxygenation. In order to explain this difference, we examined the crystal structures of both substrate-bound forms of BphAE{sub RR41} obtained under anaerobic conditions. This structure analysis, in combination with biochemical data for a Ser283Gly mutant provided evidences that the substrate is compelled to move after oxygen-binding in BphAE{sub RR41}:dibenzofuran. In BphAE{sub RR41}:2-chlorodibenzofuran, the chlorine atom is close to the side chain of Ser283. This contact is missing in the BphAE{sub RR41}:dibenzofuran, and strong enough in the BphAE{sub RR41}:2-chlorodibenzofuran to help prevent substrate movement during the catalytic reaction.

  2. Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia

    Directory of Open Access Journals (Sweden)

    Ferrero Marcela A

    2008-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs, widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination. Results Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (r = 0.834, p nahAc-like genes, phnAc-like genes as identified in Alcaligenes faecalis AFK2, and phnA1-like genes from marine PAH-degraders from the genus Cycloclasticus. Conclusion These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.

  3. Robust crop resistance to broadleaf and grass herbicides provided by aryloxyalkanoate dioxygenase transgenes.

    Science.gov (United States)

    Wright, Terry R; Shan, Guomin; Walsh, Terence A; Lira, Justin M; Cui, Cory; Song, Ping; Zhuang, Meibao; Arnold, Nicole L; Lin, Gaofeng; Yau, Kerrm; Russell, Sean M; Cicchillo, Robert M; Peterson, Mark A; Simpson, David M; Zhou, Ning; Ponsamuel, Jayakumar; Zhang, Zhanyuan

    2010-11-23

    Engineered glyphosate resistance is the most widely adopted genetically modified trait in agriculture, gaining widespread acceptance by providing a simple robust weed control system. However, extensive and sustained use of glyphosate as a sole weed control mechanism has led to field selection for glyphosate-resistant weeds and has induced significant population shifts to weeds with inherent tolerance to glyphosate. Additional weed control mechanisms that can complement glyphosate-resistant crops are, therefore, urgently needed. 2,4-dichlorophenoxyacetic acid (2,4-D) is an effective low-cost, broad-spectrum herbicide that controls many of the weeds developing resistance to glyphosate. We investigated the substrate preferences of bacterial aryloxyalkanoate dioxygenase enzymes (AADs) that can effectively degrade 2,4-D and have found that some members of this class can act on other widely used herbicides in addition to their activity on 2,4-D. AAD-1 cleaves the aryloxyphenoxypropionate family of grass-active herbicides, and AAD-12 acts on pyridyloxyacetate auxin herbicides such as triclopyr and fluroxypyr. Maize plants transformed with an AAD-1 gene showed robust crop resistance to aryloxyphenoxypropionate herbicides over four generations and were also not injured by 2,4-D applications at any growth stage. Arabidopsis plants expressing AAD-12 were resistant to 2,4-D as well as triclopyr and fluroxypyr, and transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations. These results show that single AAD transgenes can provide simultaneous resistance to a broad repertoire of agronomically important classes of herbicides, including 2,4-D, with utility in both monocot and dicot crops. These transgenes can help preserve the productivity and environmental benefits of herbicide-resistant crops.

  4. Resonance Raman study on indoleamine 2,3-dioxygenase: Control of reactivity by substrate-binding

    International Nuclear Information System (INIS)

    Highlights: • Indoleamine 2,3-dioygenase has been studied by resonance Raman spectroscopy. • Trp-binding to the enzyme induces high frequency shift of the Fe–His stretching mode. • Increased imidazolate character of histidine promotes the O–O bond cleavage step. • A fine-tuning of the reactivity of the O–O bond cleavage reaction is identified. • The results are consistent with the sequential oxygen-atom-transfer mechanism. - Abstract: Resonance Raman spectra of ligand-bound complexes including the 4-phenylimidazole complex and of free and L-Trp-bound forms of indoleamine 2, 3-dioxygenase in the ferric state were examined. Effects on the vinyl and propionate substituent groups of the heme were detected in a ligand-dependent fashion. The effects of phenyl group of 4-phenylimidazole on the vinyl and propionate Raman bands were evident when compared with the case of imidazole ligand. Substrate binding to the ferrous protein caused an upshift of the iron–histidine stretching mode by 3 cm−1, indicating an increase in negativity of the imidazole ring, which favors the O–O bond cleavage. The substrate binding event is likely to be communicated from the heme distal side to the iron–histidine bond through heme substituent groups and the hydrogen-bond network which includes water molecules, as identified in an X-ray structure of a 4-phenylimidazole complex. The results provide evidence for fine-tuning of the reactivity of O–O bond cleavage by the oxygenated heme upon binding of L-Trp

  5. (-)-Epigallocatechin gallate inhibits the expression of indoleamine 2,3-dioxygenase in human colorectal cancer cells.

    Science.gov (United States)

    Ogawa, Kengo; Hara, Takeshi; Shimizu, Masahito; Nagano, Junji; Ohno, Tomohiko; Hoshi, Masato; Ito, Hiroyasu; Tsurumi, Hisashi; Saito, Kuniaki; Seishima, Mitsuru; Moriwaki, Hisataka

    2012-09-01

    Immune escape, the ability of tumor cells to avoid tumor-specific immune responses, occurs during the development and progression of several types of human malignancies, including colorectal cancer (CRC). Indoleamine 2,3-dioxygenase (IDO), the tryptophan catabolic enzyme, plays a significant role in regulating the immune response and provides tumor cells with a potent tool to evade the immune system. In the present study, we examined the effects of (-)-epigallocatechin gallate (EGCG), the major catechin in green tea, on the inhibition of IDO expression induced by interferon (IFN)-γ in human CRC cells. We found that IFN-γ increased the expression levels of IDO protein and mRNA in HT29 and SW837 CRC cell lines. Treatment of SW837 cells with EGCG significantly decreased IFN-γ-induced expression of IDO protein and mRNA in a dose-dependent manner. Enzymatic activity of IDO, determined by the concentration of L-kynurenine in the culture medium, was also significantly inhibited by EGCG treatment. Phosphorylation of signal transducer and activator of transcription 1 (STAT1) induced by IFN-γ was also significantly inhibited by EGCG. Reporter assays indicated that EGCG inhibited the transcriptional activities of IDO promoters, IFN-stimulated response element and IFN-γ activation sequence, activated by STAT1 phosphorylation. These findings suggest that EGCG may exert antitumor effects on CRC, at least in part, by inhibiting the expression and function of IDO through the suppression of STAT1 activation. EGCG may, thus, serve as a potential agent for antitumor immunotherapy and be useful in the chemoprevention and/or treatment of CRC. PMID:23741252

  6. The immune system strikes back: cellular immune responses against indoleamine 2,3-dioxygenase.

    Directory of Open Access Journals (Sweden)

    Rikke Baek Sørensen

    Full Text Available BACKGROUND: The enzyme indoleamine 2,3-dioxygenase (IDO exerts an well established immunosuppressive function in cancer. IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it promotes the establishment of peripheral immune tolerance to tumor antigens. In the present study, we tested the notion whether IDO itself may be subject to immune responses. METHODS AND FINDINGS: The presence of naturally occurring IDO-specific CD8 T cells in cancer patients was determined by MHC/peptide stainings as well as ELISPOT. Antigen specific cytotoxic T lymphocytes (CTL from the peripheral blood of cancer patients were cloned and expanded. The functional capacity of the established CTL clones was examined by chrome release assays. The study unveiled spontaneous cytotoxic T-cell reactivity against IDO in peripheral blood as well as in the tumor microenvironment of different cancer patients. We demonstrate that these IDO reactive T cells are indeed peptide specific, cytotoxic effector cells. Hence, IDO reactive T cells are able to recognize and kill tumor cells including directly isolated AML blasts as well as IDO-expressing dendritic cells, i.e. one of the major immune suppressive cell populations. CONCLUSION: IDO may serve as an important and widely applicable target for anti-cancer immunotherapeutic strategies. Furthermore, as emerging evidence suggests that IDO constitutes a significant counter-regulatory mechanism induced by pro-inflammatory signals, IDO-based immunotherapy holds the promise to boost anti-cancer immunotherapy in general.

  7. In vivo correction with recombinant adenovirus of 4-hydroxyphenylpyruvic acid dioxygenase deficiencies in strain III mice.

    Science.gov (United States)

    Kubo, S; Kiwaki, K; Awata, H; Katoh, H; Kanegae, Y; Saito, I; Yamamoto, T; Miyazaki, J; Matsuda, I; Endo, F

    1997-01-01

    Tyrosinemia type 3, caused by a genetic deficiency of 4-hydroxyphenylpyruvic acid dioxygenase (HPD) in tyrosine catabolism, is characterized by convulsion, ataxia, and mental retardation. The III mouse is a model of tyrosinemia type 3. HPD activity and protein are defective in the liver and its blood tyrosine levels are elevated, the range being between 1,100 and 1,656 microM. We constructed a recombinant adenoviral vector bearing the human HPD cDNA (AdexCAGhHPD), which is expressed under the control of a potent CAG promoter. III mice were injected with 1.0 x 10(8) to 1.0 x 10(9) pfu of AdexCAGhHPD through the tail vein. When 3.0 x 10(8) - 1.0 x 10(9) pfu were injected, blood tyrosine levels decreased within 3 hr, reached a normal range (under 300 microM), and remained at a low level for 2-6 weeks. Hepatic HPD activities also increased as early as 3 hr after the injection of 5.0 x 10(8) pfu, reached the levels comparable to the control mice in 3-7 days, and then decreased, and correlated well to blood tyrosine. Hepatic HPD expression was confirmed by Northern blot and immunoblot analyses. Histology revealed no difference (gross or microscopic) between the liver injected with AdexCAGhHPD and the control. No significant changes in blood tyrosine levels were noted after the second injection of 5.0 x 10(8) pfu of AdexCAGhHPD. Thus, the intravenous administration of the adenoviral vector bearing a foreign gene seems suitable for transient, early gene transfer into the liver.

  8. Structure of 4-hydrophenylpyruvic acid dioxygenase (HPD) gene and its mutation in tyrosinemic mouse strain III

    Energy Technology Data Exchange (ETDEWEB)

    Awata, H.; Endo, F.; Matsuda, I. [Kumamoto Univ. Medical School (Japan)] [and others

    1994-09-01

    4-Hydroxphenylpyruvic acid dioxygenase (HPD) is an important enzyme in tyrosine catabolism in most organisms. The activity of this enzyme is expressed mainly in the liver and is developmentally regulated in mammals. A genetic deficiency of the enzyme in man and mouse leads to hereditary tyrosinemia type 3. Using human HPD cDNA as a probe, a chromosomal gene related to HPD was isolated from human and mouse gene libraries. The human HPD gene is over 30 kilo-bases long and is split into 14 exons. Analysis of the 5{prime} flanking sequence of the gene suggests that expression of the gene is regulated by hepatocyte-specific and liver-enriched transcription factors, as well as by hormones. These features of the 5{prime} flanking region of the gene are similar to those of other genes which are specifically expressed in hepatocytes and which are developmentally regulated. The gene for mouse HPD has a similar structure and we obtained evidence for a nucleotide substitution which generates a termination codon in exon 7 of the HPD gene in III mice. This mutation associates a partial exon skipping and most of the mRNA lacks sequences corresponding to exon 7. The partial exon skipping apparently is the result of a nonsense mutation in the exon. Thus, mouse strain III can serve as a genetic model for human tyrosinemia type 3. Ongoing studies are expected to elucidate the disease process involved in hereditary tyrosinemia type 1 and to shed light on mechanisms that mediate developmental regulation of HPD gene expression. In addition, mouse strain III together with recently established models for tyrosinemia type 1 will facilitate studies on hereditary tyrosinemias.

  9. Characteristics and function of sulfur dioxygenase in Echiuran worm Urechis unicinctus.

    Directory of Open Access Journals (Sweden)

    Litao Zhang

    Full Text Available BACKGROUND: Sulfide is a common toxin to animals and is abundant in coastal and aquatic sediments. Sulfur dioxygenase (SDO is thought to be the key enzyme involved in sulfide oxidation in some organisms. The echiuran worm, Urechis unicinctus, inhabits coastal sediment and tolerates high concentrations of sulfide. The SDO is presumably important for sulfide tolerance in U. unicinctus. RESULTS: The full-length cDNA of SDO from the echiuran worm U. unicinctus, proven to be located in the mitochondria, was cloned and the analysis of its sequence suggests that it belongs to the metallo-β-lactamase superfamily. The enzyme was produced using an E. coli expression system and the measured activity is approximately 0.80 U mg protein(-1. Furthermore, the expression of four sub-segments of the U. unicinctus SDO was accomplished leading to preliminary identification of functional domains of the enzyme. The identification of the conserved metal I (H113, H115, H169 and D188, metal II (D117, H118, H169 and H229 as well as the potential glutathione (GSH (R197, Y231, M279 and I283 binding sites was determined by enzyme activity and GSH affinity measurements. The key residues responsible for SDO activity were identified by analysis of simultaneous mutations of residues D117 and H118 located close to the metal II binding site. CONCLUSION: The recombinant SDO from U. unicinctus was produced, purified and characterized. The metal binding sites in the SDO were identified and Y231 recognized as the mostly important amino acid residue for GSH binding. Our results show that SDO is located in the mitochondria where it plays an important role in sulfide detoxification of U. unicinctus.

  10. Inflated kinetic isotope effects in the branched mechanism of Neurospora crassa 2-nitropropane dioxygenase.

    Science.gov (United States)

    Francis, Kevin; Gadda, Giovanni

    2009-03-24

    Catalytic turnover of Neurospora crassa 2-nitropropane dioxygenase with nitroethane as substrate occurs through both nonoxidative and oxidative pathways. The pH dependence of the kinetic isotope effects with [1,1-(2)H(2)]nitroethane as substrate was measured in the current study by monitoring the formation of the nitronate product in the nonoxidative pathway. The kinetic isotope effect on the second-order rate constant for nitronate formation, k(cat)/K(m), decreased from an upper limiting value of 23 +/- 1 at low pH to a lower limiting value of 11 +/- 1 at high pH. These kinetic isotope effects are three times larger than those determined previously through measurements of oxygen consumption that occurs in the oxidative pathway of the enzyme [(2006) Biochemistry 45, 13889]. Analytical expressions for the k(cat)/K(m) values determined in each study show that the difference in the kinetic isotope effects arises from the branching of an enzyme-ethylnitronate reaction intermediate through oxidative and nonoxidative turnover. This branching is isotope sensitive due to a kinetic isotope effect on nitronate release rather than on flavin reduction as indicated by the pH-independent (D)k(red) value of 0.99 +/- 0.06 with ethylnitronate as substrate. The kinetic isotope effect on ethylnitronate release arises from the deprotonation of histidine 196, which provides electrostatic interactions with the nitronate to keep it bound in the active site for oxidation. The isotope effect on branching results in an inflation of the kinetic isotope observed for the nonoxidative pathway to values that are larger than the intrinsic values associated with CH bond cleavage. PMID:19199786

  11. Robust crop resistance to broadleaf and grass herbicides provided by aryloxyalkanoate dioxygenase transgenes.

    Science.gov (United States)

    Wright, Terry R; Shan, Guomin; Walsh, Terence A; Lira, Justin M; Cui, Cory; Song, Ping; Zhuang, Meibao; Arnold, Nicole L; Lin, Gaofeng; Yau, Kerrm; Russell, Sean M; Cicchillo, Robert M; Peterson, Mark A; Simpson, David M; Zhou, Ning; Ponsamuel, Jayakumar; Zhang, Zhanyuan

    2010-11-23

    Engineered glyphosate resistance is the most widely adopted genetically modified trait in agriculture, gaining widespread acceptance by providing a simple robust weed control system. However, extensive and sustained use of glyphosate as a sole weed control mechanism has led to field selection for glyphosate-resistant weeds and has induced significant population shifts to weeds with inherent tolerance to glyphosate. Additional weed control mechanisms that can complement glyphosate-resistant crops are, therefore, urgently needed. 2,4-dichlorophenoxyacetic acid (2,4-D) is an effective low-cost, broad-spectrum herbicide that controls many of the weeds developing resistance to glyphosate. We investigated the substrate preferences of bacterial aryloxyalkanoate dioxygenase enzymes (AADs) that can effectively degrade 2,4-D and have found that some members of this class can act on other widely used herbicides in addition to their activity on 2,4-D. AAD-1 cleaves the aryloxyphenoxypropionate family of grass-active herbicides, and AAD-12 acts on pyridyloxyacetate auxin herbicides such as triclopyr and fluroxypyr. Maize plants transformed with an AAD-1 gene showed robust crop resistance to aryloxyphenoxypropionate herbicides over four generations and were also not injured by 2,4-D applications at any growth stage. Arabidopsis plants expressing AAD-12 were resistant to 2,4-D as well as triclopyr and fluroxypyr, and transgenic soybean plants expressing AAD-12 maintained field resistance to 2,4-D over five generations. These results show that single AAD transgenes can provide simultaneous resistance to a broad repertoire of agronomically important classes of herbicides, including 2,4-D, with utility in both monocot and dicot crops. These transgenes can help preserve the productivity and environmental benefits of herbicide-resistant crops. PMID:21059954

  12. Adjuvant indoleamine 2,3-dioxygenase enzyme inhibition for comprehensive management of epilepsy and comorbid depression.

    Science.gov (United States)

    Singh, Tanveer; Goel, Rajesh Kumar

    2016-08-01

    Epilepsy is one of the major neurological disorders frequently associated with psychiatric disorders such as depression. Alteration of tryptophan metabolism towards kynurenine pathway may be one of the plausible reasons for association of depression in epilepsy. Hence, this study was envisaged to evaluate the dose dependent inhibition of indoleamine 2,3-dioxygenase (IDO) enzyme (responsible for shifting tryptophan metabolism) employing minocycline with valproic acid for comprehensive management of epilepsy and comorbid depression. Kindling was induced in male swiss albino mice by administration of pentylenetetrazole subconvulsive dose (35mg/kg, i.p.) at an interval of 48±2h. Kindled animals were treated with saline, valproate (300mg/kg/day i.p.), valproate in combination with different doses of minocycline (10mg/kg; 20mg/kg; 40mg/kg)/day i.p. and minocycline per se (40mg/kg/day i.p.) for 15 days. Except naïve, all the groups were challenged with pentylenetetrazole (35mg/kg i.p.) on day 5, 10, and 15 to evaluate the seizure severity score. Depression was evaluated in all experimental groups using tail suspension and forced swim test on days 1, 5, 10 and 15, 2h after pentylenetetrazole challenge. Results suggested that saline treated kindled animals were significantly associated with depression. Chronic valproate treatment significantly reduced seizure severity score but unable to ameliorate the associated depression. Minocycline supplementation with valproic acid dose dependently ameliorated depression associated with epilepsy. Neurochemical and biochemical findings also supported the behavioural findings of the study. Thus, our results suggested that supplementation of IDO enzyme inhibitors with valproic acid could be explored further for comprehensive management of epilepsy and associated depression. PMID:27189423

  13. Differential regulation of macropinocytosis by Abi1/Hssh3bp1 isoforms.

    Directory of Open Access Journals (Sweden)

    Patrycja M Dubielecka

    Full Text Available BACKGROUND: Macropinocytosis, which is a constitutive cellular process of fluid and macromolecule uptake, is regulated by actin cytoskeleton rearrangements near the plasma membrane. Activation of Rac1, which is proposed to act upstream of the actin polymerization regulatory Wave 2 complex, has been found to correlate with enhanced macropinocytosis. One of the components of the Wave 2 complex is Abi1. Multiple, alternatively spliced isoforms of Abi1 are expressed in mammalian cells, but the functional significance of the various isoforms is unknown. PRINCIPAL FINDINGS: Here, using flow cytometric assay analysis for Alexa Fluor 647, we demonstrate that Abi1 isoforms 2 and 3 differentially regulate macropinocytosis. LNCaP cells expressing isoform 3 had increased macropinocytic uptake that correlated with enhanced cell spreading and higher Rac1 activation in comparison to cells expressing isoform 2. Isoform 2 expressing cells had decreased macropinocytic uptake, but demonstrated greater sensitivity to Rac1 activation. Moreover, more isoform 2 was localized within the cytoplasm in comparison to isoform 3, which was more associated with the plasma membrane. Activated Rac1 was found to specifically bind to a site in exon 10 of isoform 2 in vitro. Because of alternative mRNA splicing, exon 10 is absent from isoform 3, precluding similar binding of activated Rac1. Both isoforms, however, bound to inactive Rac1 through the same non-exon 10 site. Thus, Abi1 isoform 3-containing Wave 2 complex exhibited a differential binding to activated vs. inactive Rac1, whereas isoform 2-containing Wave 2 complex bound activated or inactive Rac1 comparably. CONCLUSION: Based on these observations, we postulate that Abi1 isoforms differentially regulate macropinocytosis as a consequence of their different relative affinities for activated Rac1 in Wave 2 complex. These findings also raise the possibility that isoform-specific roles occur in other Abi1 functions.

  14. The Reaumuria trigyna leucoanthocyanidin dioxygenase (RtLDOX) gene complements anthocyanidin synthesis and increases the salt tolerance potential of a transgenic Arabidopsis LDOX mutant.

    Science.gov (United States)

    Zhang, Huirong; Du, Chao; Wang, Yan; Wang, Jia; Zheng, Linlin; Wang, Yingchun

    2016-09-01

    Reaumuria trigyna is a typical, native desert halophyte that grows under extreme conditions in Inner Mongolia. In a previous transcriptomic profiling analysis, flavonoid pathway-related genes in R. trigyna showed significant differences in transcript abundance under salt stress. Leucoanthocyanidin dioxygenase (LDOX, EC 1.14.11.19) is one of three dioxygenases in the flavonoid pathway that catalyzes the formation of anthocyanidins from leucoanthocyanidins. In this study, we cloned the full-length cDNA of R. trigyna LDOX (RtLDOX), and found RtLDOX recombinant protein was able to replace flavanone-3-hydroxylase (F3H, EC 1.14.11.9), another dioxygenase in the flavonoid pathway, to convert naringenin to dihydrokaempferol in vitro. R. trigyna LDOX can complement the Arabidopsis LDOX mutant transparent testa11 (tt11-11), which has reduced proanthocyanin (PA) and anthocyanin levels in seeds, to accumulate these two compounds. Thus, RtLDOX acts as a multifunctional dioxygenase to effect the synthesis of PA and anthocyanins and can perform F3H dioxygenase activities in the flavonoid biosynthesis pathway. The RtLDOX promoter harbored many cis-acting elements that might be recognized and bound by transcription factors related to stress response. RtLDOX expression was strongly increased under salt stress, and RtLDOX transgenic Arabidopsis mutant under NaCl stress accumulated the content of flavonoids leading to an increased antioxidant activities and plant biomass. These results suggest that RtLDOX as a multifunctional dioxygenase in flavonoid biosynthesis involves in enhancing plant response to NaCl stress. PMID:27219053

  15. Structure of Naegleria Tet-like dioxygenase (NgTet1) in complexes with a reaction intermediate 5-hydroxymethylcytosine DNA

    OpenAIRE

    Hashimoto, Hideharu; Pais, June E.; Dai, Nan; Corrêa, Ivan R; Zhang, Xing; Zheng, Yu; Cheng, Xiaodong

    2015-01-01

    The family of ten-eleven translocation (Tet) dioxygenases is widely distributed across the eukaryotic tree of life, from mammals to the amoeboflagellate Naegleria gruberi. Like mammalian Tet proteins, the Naegleria Tet-like protein, NgTet1, acts on 5-methylcytosine (5mC) and generates 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) in three consecutive, Fe(II)- and α-ketoglutarate-dependent oxidation reactions. The two intermediates, 5hmC and 5fC, could be...

  16. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine-200

    OpenAIRE

    Kovaleva, Elena G.; Rogers, Melanie S.; Lipscomb, John D.

    2015-01-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homo...

  17. Characterization of four hemocyanin isoforms in Litopenaeus vannamei

    Institute of Scientific and Technical Information of China (English)

    XU Jingxiang; RUAN Lingwei; LI Zhen; YU Xiaoman; LI Sedong; SHI Hong; XU Xun

    2015-01-01

    In this study, the gene encoding hemocyanin subunit L, LvHcL, was cloned from Litopenaeus vannamei and the genomic organization was characterized. This gene was diverse with many SNPs and also had at least four isoforms, while one of them (LvHcL4) only had two exons and the exon2 was missed. Transcription analysis showed that these isoforms of LvHcL were up-regulated after WSSV challenge in WSSV-resistant shrimp, while the transcriptions were decreased constantly in WSSV-susceptible shrimp. It is suggested that the hemocyanin had rich polymorphism and was involved in the antiviral response. These results could extend our previous findings and provide insights into the immune feature of hemocyanin, which would be helpful for further studies aimed at antiviral mechanism in inver-tebrate.

  18. Differential regulation of renal phospholipase C isoforms by catecholamines.

    OpenAIRE

    Yu, P Y; Asico, L D; Eisner, G M; Jose, P A

    1995-01-01

    Dopamine and D1 agonists and NE all increase phosphatidyl inositol-specific phospholipase C (PLC) activity, but whereas dopamine produces a natriuresis, NE has an antinatriuretic effect. To determine if catecholamines differentially regulate the expression of PLC isoforms, we infused fenoldopam, a D1 agonist, or pramipexole, a D1/D2 agonist, intravenously or infused fenoldopam or NE into the renal artery of anesthetized rats. After 3-4 h of infusion, when the expected natriuresis (fenoldopam ...

  19. GABAB(1) receptor subunit isoforms differentially regulate stress resilience

    OpenAIRE

    O’Leary, Olivia F.; Felice, Daniela; Galimberti, Stefano; Savignac, Hélène M.; Bravo, Javier A.; Crowley, Tadhg; El Yacoubi, Malika; Vaugeois, Jean-Marie; Gassmann, Martin; Bettler, Bernhard; Dinan, Timothy G.; Cryan, John F.

    2014-01-01

    Stress can increase susceptibility to developing psychiatric disorders, including depression. Understanding the neurobiological mechanisms underlying stress resilience and susceptibility is key to identifying novel targets for the development of more effective treatments for stress-related psychiatric disorders. Here we show that specific isoforms of GABAB receptor subunits differentially regulate stress resilience. Specifically, GABAB(1a)−/− mice are more susceptible whereas GABAB(1b)−/− mic...

  20. Characterisation of CDKL5 Transcript Isoforms in Human and Mouse.

    Directory of Open Access Journals (Sweden)

    Ralph D Hector

    Full Text Available Mutations in the X-linked Cyclin-Dependent Kinase-Like 5 gene (CDKL5 cause early onset infantile spasms and subsequent severe developmental delay in affected children. Deleterious mutations have been reported to occur throughout the CDKL5 coding region. Several studies point to a complex CDKL5 gene structure in terms of exon usage and transcript expression. Improvements in molecular diagnosis and more extensive research into the neurobiology of CDKL5 and pathophysiology of CDKL5 disorders necessitate an updated analysis of the gene. In this study, we have analysed human and mouse CDKL5 transcript patterns both bioinformatically and experimentally. We have characterised the predominant brain isoform of CDKL5, a 9.7 kb transcript comprised of 18 exons with a large 6.6 kb 3'-untranslated region (UTR, which we name hCDKL5_1. In addition we describe new exonic regions and a range of novel splice and UTR isoforms. This has enabled the description of an updated gene model in both species and a standardised nomenclature system for CDKL5 transcripts. Profiling revealed tissue- and brain development stage-specific differences in expression between transcript isoforms. These findings provide an essential backdrop for the diagnosis of CDKL5-related disorders, for investigations into the basic biology of this gene and its protein products, and for the rational design of gene-based and molecular therapies for these disorders.

  1. Characterisation of CDKL5 Transcript Isoforms in Human and Mouse.

    Science.gov (United States)

    Hector, Ralph D; Dando, Owen; Landsberger, Nicoletta; Kilstrup-Nielsen, Charlotte; Kind, Peter C; Bailey, Mark E S; Cobb, Stuart R

    2016-01-01

    Mutations in the X-linked Cyclin-Dependent Kinase-Like 5 gene (CDKL5) cause early onset infantile spasms and subsequent severe developmental delay in affected children. Deleterious mutations have been reported to occur throughout the CDKL5 coding region. Several studies point to a complex CDKL5 gene structure in terms of exon usage and transcript expression. Improvements in molecular diagnosis and more extensive research into the neurobiology of CDKL5 and pathophysiology of CDKL5 disorders necessitate an updated analysis of the gene. In this study, we have analysed human and mouse CDKL5 transcript patterns both bioinformatically and experimentally. We have characterised the predominant brain isoform of CDKL5, a 9.7 kb transcript comprised of 18 exons with a large 6.6 kb 3'-untranslated region (UTR), which we name hCDKL5_1. In addition we describe new exonic regions and a range of novel splice and UTR isoforms. This has enabled the description of an updated gene model in both species and a standardised nomenclature system for CDKL5 transcripts. Profiling revealed tissue- and brain development stage-specific differences in expression between transcript isoforms. These findings provide an essential backdrop for the diagnosis of CDKL5-related disorders, for investigations into the basic biology of this gene and its protein products, and for the rational design of gene-based and molecular therapies for these disorders.

  2. Antagonistic functions of two stardust isoforms in Drosophila photoreceptor cells.

    Science.gov (United States)

    Bulgakova, Natalia A; Rentsch, Michaela; Knust, Elisabeth

    2010-11-15

    Membrane-associated guanylate kinases (MAGUKs) are scaffolding proteins that organize supramolecular protein complexes, thereby partitioning the plasma membrane into spatially and functionally distinct subdomains. Their modular organization is ideally suited to organize protein complexes with cell type- or stage-specific composition, or both. Often more than one MAGUK isoform is expressed by one gene in the same cell, yet very little is known about their individual in vivo functions. Here, we show that two isoforms of Drosophila stardust, Sdt-H (formerly called Sdt-B2) and Sdt-D, which differ in their N terminus, are expressed in adult photoreceptors. Both isoforms associate with Crumbs and PATJ, constituents of the conserved Crumbs-Stardust complex. However, they form distinct complexes, localized at the stalk, a restricted region of the apical plasma membrane. Strikingly, Sdt-H and Sdt-D have antagonistic functions. While Sdt-H overexpression increases stalk membrane length and prevents light-dependent retinal degeneration, Sdt-D overexpression reduces stalk length and enhances light-dependent retinal degeneration. These results suggest that a fine-tuned balance of different Crumbs complexes regulates photoreceptor homeostasis.

  3. Characterisation of CDKL5 Transcript Isoforms in Human and Mouse

    Science.gov (United States)

    Dando, Owen; Landsberger, Nicoletta; Kilstrup-Nielsen, Charlotte; Kind, Peter C.; Bailey, Mark E. S.; Cobb, Stuart R.

    2016-01-01

    Mutations in the X-linked Cyclin-Dependent Kinase-Like 5 gene (CDKL5) cause early onset infantile spasms and subsequent severe developmental delay in affected children. Deleterious mutations have been reported to occur throughout the CDKL5 coding region. Several studies point to a complex CDKL5 gene structure in terms of exon usage and transcript expression. Improvements in molecular diagnosis and more extensive research into the neurobiology of CDKL5 and pathophysiology of CDKL5 disorders necessitate an updated analysis of the gene. In this study, we have analysed human and mouse CDKL5 transcript patterns both bioinformatically and experimentally. We have characterised the predominant brain isoform of CDKL5, a 9.7 kb transcript comprised of 18 exons with a large 6.6 kb 3’-untranslated region (UTR), which we name hCDKL5_1. In addition we describe new exonic regions and a range of novel splice and UTR isoforms. This has enabled the description of an updated gene model in both species and a standardised nomenclature system for CDKL5 transcripts. Profiling revealed tissue- and brain development stage-specific differences in expression between transcript isoforms. These findings provide an essential backdrop for the diagnosis of CDKL5-related disorders, for investigations into the basic biology of this gene and its protein products, and for the rational design of gene-based and molecular therapies for these disorders. PMID:27315173

  4. Molecular mechanical differences between isoforms of contractile actin in the presence of isoforms of smooth muscle tropomyosin.

    OpenAIRE

    Lennart Hilbert; Genevieve Bates; Roman, Horia N.; Jenna L Blumenthal; Zitouni, Nedjma B.; Apolinary Sobieszek; Mackey, Michael C.; Anne-Marie Lauzon

    2013-01-01

    The proteins involved in smooth muscle's molecular contractile mechanism - the anti-parallel motion of actin and myosin filaments driven by myosin heads interacting with actin - are found as different isoforms. While their expression levels are altered in disease states, their relevance to the mechanical interaction of myosin with actin is not sufficiently understood. Here, we analyzed in vitro actin filament propulsion by smooth muscle myosin for [Formula: see text]-actin ([Formula: see text...

  5. Overexpression of the rice carotenoid cleavage dioxygenase 1 gene in Golden Rice endosperm suggests apocarotenoids as substrates in planta.

    Science.gov (United States)

    Ilg, Andrea; Yu, Qiuju; Schaub, Patrick; Beyer, Peter; Al-Babili, Salim

    2010-08-01

    Carotenoids are converted by carotenoid cleavage dioxygenases that catalyze oxidative cleavage reactions leading to apocarotenoids. However, apocarotenoids can also be further truncated by some members of this enzyme family. The plant carotenoid cleavage dioxygenase 1 (CCD1) subfamily is known to degrade both carotenoids and apocarotenoids in vitro, leading to different volatile compounds. In this study, we investigated the impact of the rice CCD1 (OsCCD1) on the pigmentation of Golden Rice 2 (GR2), a genetically modified rice variety accumulating carotenoids in the endosperm. For this purpose, the corresponding cDNA was introduced into the rice genome under the control of an endosperm-specific promoter in sense and anti-sense orientations. Despite high expression levels of OsCCD1 in sense plants, pigment analysis revealed carotenoid levels and patterns comparable to those of GR2, pleading against carotenoids as substrates in rice endosperm. In support, similar carotenoid contents were determined in anti-sense plants. To check whether OsCCD1 overexpressed in GR2 endosperm is active, in vitro assays were performed with apocarotenoid substrates. HPLC analysis confirmed the cleavage activity of introduced OsCCD1. Our data indicate that apocarotenoids rather than carotenoids are the substrates of OsCCD1 in planta. PMID:20549230

  6. Multistep conversion of para-substituted phenols by phenol hydroxylase and 2,3-dihydroxybiphenyl 1,2-dioxygenase.

    Science.gov (United States)

    Qu, Yuanyuan; Shi, Shengnan; Ma, Qiao; Kong, Chunlei; Zhou, Hao; Zhang, Xuwang; Zhou, Jiti

    2013-04-01

    A multistep conversion system of para-substituted phenols by recombinant phenol hydroxylase (PH(IND)) and 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC(LA-4)) was constructed in this study. Docking studies with different para-substituted phenols and corresponding catechols inside of the active site of PH(IND) and BphC(LA-4) predicted that all the substrates should be transformed. High-performance liquid chromatography-mass spectrometry analysis showed that the products of multistep conversion were the corresponding para-substituted catechols and semialdehydes. For the first-step conversion, the formation rate of 4-fluorocatechol (0.39 μM/min/mg dry weight) by strain PH(IND) hydroxylation was 1.15, 6.50, 3.00, and 1.18-fold higher than the formation of 4-chlorocatechol, 4-bromocatechol, 4-nitrocatechol, and 4-methylcatechol, respectively. For the second-step conversion, the formation rates of semialdehydes by strain BphC(LA-4) were as follows: 5-fluoro-HODA>5-chloro-HODA>2-hydroxy-5-nitro-ODA>5-bromo-HODA>2-hydroxy-5-methyl-ODA. The present study suggested that the multistep conversion by both ring hydroxylase and cleavage dioxygenase should be potential in the synthesis of industrial precursors and provide a novel avenue in the wastewater recycling treatment.

  7. Molecular basis for catalysis and substrate-mediated cellular stabilization of human tryptophan 2,3-dioxygenase

    Science.gov (United States)

    Lewis-Ballester, Ariel; Forouhar, Farhad; Kim, Sung-Mi; Lew, Scott; Wang, YongQiang; Karkashon, Shay; Seetharaman, Jayaraman; Batabyal, Dipanwita; Chiang, Bing-Yu; Hussain, Munif; Correia, Maria Almira; Yeh, Syun-Ru; Tong, Liang

    2016-01-01

    Tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) play a central role in tryptophan metabolism and are involved in many cellular and disease processes. Here we report the crystal structure of human TDO (hTDO) in a ternary complex with the substrates L-Trp and O2 and in a binary complex with the product N-formylkynurenine (NFK), defining for the first time the binding modes of both substrates and the product of this enzyme. The structure indicates that the dioxygenation reaction is initiated by a direct attack of O2 on the C2 atom of the L-Trp indole ring. The structure also reveals an exo binding site for L-Trp, located ~42 Å from the active site and formed by residues conserved among tryptophan-auxotrophic TDOs. Biochemical and cellular studies indicate that Trp binding at this exo site does not affect enzyme catalysis but instead it retards the degradation of hTDO through the ubiquitin-dependent proteasomal pathway. This exo site may therefore provide a novel L-Trp-mediated regulation mechanism for cellular degradation of hTDO, which may have important implications in human diseases. PMID:27762317

  8. The effects of trace elements, cations, and environmental conditions on protocatechuate 3,4-dioxygenase activity

    Directory of Open Access Journals (Sweden)

    Andréa Scaramal da Silva

    2013-04-01

    Full Text Available Phenanthracene is a highly toxic organic compound capable of contaminating water and soils, and biodegradation is an important tool for remediating polluted environments. This study aimed to evaluate the effects of trace elements, cations, and environmental conditions on the activity of the protocatechol 3,4-dioxygenase (P3,4O enzyme produced by the isolate Leifsonia sp. in cell-free and immobilized extracts. The isolate was grown in Luria Bertani broth medium (LB amended with 250 mg L-1 of phenanthrene. Various levels of pH (4.0-9.0, temperature (5-80 °C, time (0-90 min, trace elements (Cu2+, Hg2+ and Fe3+, and cations (Mg2+, Mn2+, K+ and NH4+ were tested to determine which conditions optimized enzyme activity. In general, the immobilized extract exhibited higher enzyme activity than the cell-free extract in the presence of trace elements and cations. Adding iron yielded the highest relative activity for both cell-free and immobilized extracts, with values of 16 and 99 %, respectively. Copper also increased enzyme activity for both cell-free and immobilized extracts, with values of 8 and 44 %, respectively. Enzyme activity in the phosphate buffer was high across a wide range of pH, reaching 80 % in the pH range between 6.5 and 8.0. The optimum temperatures for enzyme activity differed for cell-free and immobilized extracts, with maximum enzyme activity observed at 35 ºC for the cell-free extract and at 55 ºC for the immobilized extract. The cell-free extract of the P3,4O enzyme exhibited high activity only during the first 3 min of incubation, when it showed 50 % relative activity, and dropped to 0 % after 60 min of incubation. By contrast, activity in the immobilized extract was maintained during 90 min of incubation. This isolate has important characteristics for phenanthrene biodegradation, producing high quantities of the P3,4O enzyme that forms part of the most important pathway for PAH biodegradation.

  9. Virus Infections Incite Pain Hypersensitivity by Inducing Indoleamine 2,3 Dioxygenase.

    Directory of Open Access Journals (Sweden)

    Lei Huang

    2016-05-01

    Full Text Available Increased pain sensitivity is a comorbidity associated with many clinical diseases, though the underlying causes are poorly understood. Recently, chronic pain hypersensitivity in rodents treated to induce chronic inflammation in peripheral tissues was linked to enhanced tryptophan catabolism in brain mediated by indoleamine 2,3 dioxygenase (IDO. Here we show that acute influenza A virus (IAV and chronic murine leukemia retrovirus (MuLV infections, which stimulate robust IDO expression in lungs and lymphoid tissues, induced acute or chronic pain hypersensitivity, respectively. In contrast, virus-induced pain hypersensitivity did not manifest in mice lacking intact IDO1 genes. Spleen IDO activity increased markedly as MuLV infections progressed, while IDO1 expression was not elevated significantly in brain or spinal cord (CNS tissues. Moreover, kynurenine (Kyn, a tryptophan catabolite made by cells expressing IDO, incited pain hypersensitivity in uninfected IDO1-deficient mice and Kyn potentiated pain hypersensitivity due to MuLV infection. MuLV infection stimulated selective IDO expression by a discreet population of spleen cells expressing both B cell (CD19 and dendritic cell (CD11c markers (CD19+ DCs. CD19+ DCs were more susceptible to MuLV infection than B cells or conventional (CD19neg DCs, proliferated faster than B cells from early stages of MuLV infection and exhibited mature antigen presenting cell (APC phenotypes, unlike conventional (CD19neg DCs. Moreover, interactions with CD4 T cells were necessary to sustain functional IDO expression by CD19+ DCs in vitro and in vivo. Splenocytes from MuLV-infected IDO1-sufficient mice induced pain hypersensitivity in uninfected IDO1-deficient recipient mice, while selective in vivo depletion of DCs alleviated pain hypersensitivity in MuLV-infected IDO1-sufficient mice and led to rapid reduction in splenomegaly, a hallmark of MuLV immune pathogenesis. These findings reveal critical roles for CD19

  10. Virus Infections Incite Pain Hypersensitivity by Inducing Indoleamine 2,3 Dioxygenase.

    Science.gov (United States)

    Huang, Lei; Ou, Rong; Rabelo de Souza, Guilherme; Cunha, Thiago M; Lemos, Henrique; Mohamed, Eslam; Li, Lingqian; Pacholczyk, Gabriela; Randall, Janice; Munn, David H; Mellor, Andrew L

    2016-05-01

    Increased pain sensitivity is a comorbidity associated with many clinical diseases, though the underlying causes are poorly understood. Recently, chronic pain hypersensitivity in rodents treated to induce chronic inflammation in peripheral tissues was linked to enhanced tryptophan catabolism in brain mediated by indoleamine 2,3 dioxygenase (IDO). Here we show that acute influenza A virus (IAV) and chronic murine leukemia retrovirus (MuLV) infections, which stimulate robust IDO expression in lungs and lymphoid tissues, induced acute or chronic pain hypersensitivity, respectively. In contrast, virus-induced pain hypersensitivity did not manifest in mice lacking intact IDO1 genes. Spleen IDO activity increased markedly as MuLV infections progressed, while IDO1 expression was not elevated significantly in brain or spinal cord (CNS) tissues. Moreover, kynurenine (Kyn), a tryptophan catabolite made by cells expressing IDO, incited pain hypersensitivity in uninfected IDO1-deficient mice and Kyn potentiated pain hypersensitivity due to MuLV infection. MuLV infection stimulated selective IDO expression by a discreet population of spleen cells expressing both B cell (CD19) and dendritic cell (CD11c) markers (CD19+ DCs). CD19+ DCs were more susceptible to MuLV infection than B cells or conventional (CD19neg) DCs, proliferated faster than B cells from early stages of MuLV infection and exhibited mature antigen presenting cell (APC) phenotypes, unlike conventional (CD19neg) DCs. Moreover, interactions with CD4 T cells were necessary to sustain functional IDO expression by CD19+ DCs in vitro and in vivo. Splenocytes from MuLV-infected IDO1-sufficient mice induced pain hypersensitivity in uninfected IDO1-deficient recipient mice, while selective in vivo depletion of DCs alleviated pain hypersensitivity in MuLV-infected IDO1-sufficient mice and led to rapid reduction in splenomegaly, a hallmark of MuLV immune pathogenesis. These findings reveal critical roles for CD19+ DCs

  11. Immuno-regulatory function of indoleamine 2,3 dioxygenase through modulation of innate immune responses.

    Directory of Open Access Journals (Sweden)

    Malihe-Sadat Poormasjedi-Meibod

    Full Text Available Successful long-term treatment of type-1 diabetes mainly relies on replacement of β-cells via islet transplantation. Donor shortage is one of the main obstacles preventing transplantation from becoming the treatment of choice. Although animal organs could be an alternative source for transplantation, common immunosuppressive treatments demonstrate low efficacy in preventing xenorejection. Immunoprotective effects of indoleamine 2,3-dioxygenase (IDO on T-cell mediated allorejection has been extensively studied. Our studies revealed that IDO expression by fibroblasts, induced apoptosis in T-cells while not affecting non-immune cell survival/function. Since macrophages play a pivotal role in xenograft rejection, herein we investigated the effect of IDO-induced tryptophan deficiency/kynurenine accumulation on macrophage function/survival. Moreover, we evaluated the local immunosuppressive effect of IDO on islet-xenograft protection. Our results indicated that IDO expression by bystander fibroblasts significantly reduced the viability of primary macrophages via apoptosis induction. Treatment of peritoneal macrophages by IDO-expressing fibroblast conditioned medium significantly reduced their proinflammatory activity through inhibition of iNOS expression. To determine whether IDO-induced tryptophan starvation or kynurenine accumulation is responsible for macrophage apoptosis and inhibition of their proinflammatory activity, Raw264.7 cell viability and proinflammatory responses were evaluated in tryptophan deficient medium or in the presence of kynurenine. Tryptophan deficiency, but not kynurenine accumulation, reduced Raw264.7 cell viability and suppressed their proinflammatory activity. Next a three-dimensional islet-xenograft was engineered by embedding rat islets within either control or IDO-expressing fibroblast-populated collagen matrix. Islets morphology and immune cell infiltration were then studied in the xenografts transplanted into the C57

  12. NO binding to Mn-substituted homoprotocatechuate 2,3-dioxygenase: relationship to O₂ reactivity.

    Science.gov (United States)

    Hayden, Joshua A; Farquhar, Erik R; Que, Lawrence; Lipscomb, John D; Hendrich, Michael P

    2013-10-01

    Iron(II)-containing homoprotocatechuate 2,3-dioxygenase (FeHPCD) activates O2 to catalyze the aromatic ring opening of homoprotocatechuate (HPCA). The enzyme requires Fe(II) for catalysis, but Mn(II) can be substituted (MnHPCD) with essentially no change in the steady-state kinetic parameters. Near simultaneous O2 and HPCA activation has been proposed to occur through transfer of an electron or electrons from HPCA to O2 through the divalent metal. In O2 reactions with MnHPCD-HPCA and the 4-nitrocatechol (4NC) complex of the His200Asn (H200N) variant of FeHPCD, this transfer has resulted in the detection of a transient M(III)-O2 (·-) species that is not observed during turnover of the wild-type FeHPCD. The factors governing formation of the M(III)-O2 (·-) species are explored here by EPR spectroscopy using MnHPCD and nitric oxide (NO) as an O2 surrogate. Both the HPCA and the dihydroxymandelic substrate complexes of MnHPCD bind NO, thus representing the first reported stable MnNO complexes of a nonheme enzyme. In contrast, the free enzyme, the MnHPCD-4NC complex, and the MnH200N and MnH200Q variants with or without HPCA bound do not bind NO. The MnHPCD-ligand complexes that bind NO are also active in normal O2-linked turnover, whereas the others are inactive. Past studies have shown that FeHPCD and the analogous variants and catecholic ligand complexes all bind NO, and are active in normal turnover. This contrasting behavior may stem from the ability of the enzyme to maintain the approximately 0.8-V difference in the solution redox potentials of Fe(II) and Mn(II). Owing to the higher potential of Mn, the formation of the NO adduct or the O2 adduct requires both strong charge donation from the bound catecholic ligand and additional stabilization by interaction with the active-site His200. The same nonoptimal electronic and structural forces that prevent NO and O2 binding in MnHPCD variants may lead to inefficient electron transfer from the catecholic substrate to

  13. NO Binding to Mn-Substituted Homoprotocatechuate 2,3-Dioxygenase: Relationship to O2 Reactivity

    Science.gov (United States)

    Hayden, Joshua A.; Farquhar, Erik R.; Que, Lawrence; Lipscomb, John D.; Hendrich, Michael P.

    2014-01-01

    Homoprotocatechuate 2,3-dioxygenase (FeHPCD) activates O2 to catalyze the aromatic ring opening of 3,4-dihydroxyphenylacetic acid (HPCA). The enzyme requires FeII for catalysis, but MnII can be substituted (MnHPCD) with essentially no change in the steady-state kinetic parameters. Near simultaneous O2 and HPCA activation has been proposed to occur through transfer of an electron(s) from HPCA to O2 through the divalent metal. In O2 reactions with MnHPCD-HPCA and the 4-nitrocatechol (4NC) complex of the His200Asn (H200N) variant of FeHPCD, this transfer has resulted in the detection of a transient MIII-O2•− species not observed during turnover of the wild type FeHPCD. The factors governing formation of the MIII-O2•− species are explored here with EPR spectroscopy using MnHPCD and nitric oxide (NO) as an O2 surrogate. Both the HPCA and dihydroxymandelic substrate complexes of MnHPCD bind NO, thus representing the first reported stable MnNO complexes of a nonheme enzyme. In contrast, the free enzyme, the MnHPCD-4NC complex, and the MnH200N and MnH200Q variants with or without HPCA bound do not bind NO. The MnHPCD-ligand complexes that bind NO are also active in normal O2-linked turnover, whereas the others are inactive. Past studies have shown that FeHPCD and the analogous variants and catecholic ligand complexes all bind NO, and are active in normal turnover. This contrasting behavior may stem from ability of the enzyme to maintain the ~0.8 V difference in the solution redox potentials of FeII and MnII. Due to the higher potential of Mn, the formation of the NO or O2 adduct requires both strong charge donation from the bound catecholic ligand and additional stabilization by interaction with the active site His200. The same non-optimal electronic and structural forces that prevent NO and O2 binding in MnHPCD variants may lead to inefficient electron transfer from the catecholic substrate to the metal center in variants of FeHPCD during O2-linked turnover

  14. Selective glucocorticoid receptor translational isoforms reveal glucocorticoid-induced apoptotic transcriptomes.

    Science.gov (United States)

    Wu, I; Shin, S C; Cao, Y; Bender, I K; Jafari, N; Feng, G; Lin, S; Cidlowski, J A; Schleimer, R P; Lu, N Z

    2013-01-01

    Induction of T-cell apoptosis contributes to the anti-inflammatory and antineoplastic benefits of glucocorticoids. The glucocorticoid receptor (GR) translational isoforms have distinct proapoptotic activities in osteosarcoma cells. Here we determined whether GR isoforms selectively induce apoptosis in Jurkat T lymphoblastic leukemia cells. Jurkat cells stably expressing individual GR isoforms were generated and treated with vehicle or dexamethasone (DEX). DEX induced apoptosis in cells expressing the GR-A, -B, or -C, but not the GR-D, isoform. cDNA microarray analyses of cells sensitive (GR-C3) and insensitive (GR-D3) to DEX revealed glucocorticoid-induced proapoptotic transcriptomes. Genes that were regulated by the proapoptotic GR-C3, but not by the GR-D3, isoform likely contributed to glucocorticoid-induced apoptosis. The identified genes include those that are directly involved in apoptosis and those that facilitate cell killing. Chromatin immunoprecipitation assays demonstrated that distinct chromatin modification abilities may underlie the distinct functions of GR isoforms. Interestingly, all GR isoforms, including the GR-D3 isoform, suppressed mitogen-stimulated cytokines. Furthermore, the GR-C isoforms were selectively upregulated in mitogen-activated primary T cells and DEX treatment induced GR-C target genes in activated T cells. Cell-specific expressions and functions of GR isoforms may help to explain the tissue- and individual-selective actions of glucocorticoids and may provide a basis for developing improved glucocorticoids. PMID:23303127

  15. Synthesis of the Reported Pyranonaphthoquinone Structure of the Indoleamine-2,3-dioxygenase Inhibitor Annulin B by Regioselective Diels-Alder Reaction.

    Science.gov (United States)

    Inman, Martyn; Carvalho, Catarina; Lewis, William; Moody, Christopher J

    2016-09-01

    Annulin B, isolated from the marine hydroid isolated from Garveia annulata, is a potent inhibitor of the tryptophan catabolizing enzyme indoleamine-2,3-dioxygenase (IDO). A synthesis of the reported pyranonaphthoquinone structure is described, in which the key step is a regioselective Diels-Alder reaction between a pyranobenzoquinone dienophile and a silyl ketene acetal diene. PMID:27513176

  16. Gene therapy with adenovirus-delivered indoleamine 2,3-dioxygenase improves renal function and morphology following allogeneic kidney transplantation in rat

    NARCIS (Netherlands)

    Vavrincova-Yaghi, Diana; Deelman, Leo E.; van Goor, Harry; Seelen, Marc; Kema, Ido P.; Smit-van Oosten, Annemieke; de Zeeuw, Dick; Henning, Robert H.; Sandovici, Maria

    2011-01-01

    BACKGROUND: Indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme in the tryptophan catabolism, has recently emerged as an important immunosuppressive enzyme involved in the regulation of both physiologic (maternal tolerance), as well as pathologic (neoplasia, autoimmune diseases, asthma) proc

  17. NUCLEOTIDE SEQUENCING AND TRANSCRIPTIONAL MAPPING OF THE GENES ENCODING BIPHENYL DIOXYGENASE, A MULTICOM- PONENT POLYCHLORINATED-BIPHENYL-DEGRADING ENZYME IN PSEUDOMONAS STRAIN LB400

    Science.gov (United States)

    The DNA region encoding biphenyl dioxygenase, the first enzyme in the biphenyl-polychlorinated biphenyl degradation pathway of Pseudomonas species strain LB400, was sequenced. Six open reading frames were identified, four of which are homologous to the components of toluene dioxy...

  18. Modeling the 2-His-1-Carboxylate Facial Triad: Iron-Catecholato Complexes as Structural and Functional Models of the Extradiol Cleaving Dioxygenases

    NARCIS (Netherlands)

    Bruijnincx, P.C.A.; Lutz, M.; Spek, A.L.; Hagen, W.R.; Weckhuysen, B.M.; van Koten, G.; Klein Gebbink, R.J.M.

    2007-01-01

    Mononuclear iron(II)- and iron(III)-catecholato complexes with three members of a new 3,3-bis(1-alkylimidazol-2-yl)propionate ligand family have been synthesized as models of the active sites of the extradiol cleaving catechol dioxygenases. These enzymes are part of the superfamily of dioxygen-activ

  19. PKC isoforms interact with and phosphorylate DNMT1

    Directory of Open Access Journals (Sweden)

    Pradhan Sriharsa

    2011-05-01

    Full Text Available Abstract Background DNA methyltransferase 1 (DNMT1 has been shown to be phosphorylated on multiple serine and threonine residues, based on cell type and physiological conditions. Although recent studies have suggested that protein kinase C (PKC may be involved, the individual contribution of PKC isoforms in their ability to phosphorylate DNMT1 remains unknown. The PKC family consists of at least 12 isoforms that possess distinct differences in structure, substrate requirement, expression and localization. Results Here we show that PKCα, βI, βII, δ, γ, η, ζ and μ preferentially phosphorylate the N-terminal domain of human DNMT1. No such phosphorylation of DNMT1 was observed with PKCε. Using PKCζ as a prototype model, we also found that PKC physically interacts with and phosphorylates DNMT1. In vitro phosphorylation assays conducted with recombinant fragments of DNMT1 showed that PKCζ preferentially phosphorylated the N-terminal region of DNMT1. The interaction of PKCζ with DNMT1 was confirmed by GST pull-down and co-immunoprecipitation experiments. Co-localization experiments by fluorescent microscopy further showed that endogenous PKCζ and DNMT1 were present in the same molecular complex. Endogenous PKCζ activity was also detected when DNMT1 was immunoprecipitated from HEK-293 cells. Overexpression of both PKCζ and DNMT1 in HEK-293 cells, but not of either alone, reduced the methylation status of genes distributed across the genome. Moreover, in vitro phosphorylation of DNMT1 by PKCζ reduced its methytransferase activity. Conclusions Our results indicate that phosphorylation of human DNMT1 by PKC is isoform-specific and provides the first evidence of cooperation between PKCζ and DNMT1 in the control of the DNA methylation patterns of the genome.

  20. The FU gene and its possible protein isoforms

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    Nöthen Markus M

    2004-07-01

    Full Text Available Abstract Background FU is the human homologue of the Drosophila gene fused whose product fused is a positive regulator of the transcription factor Cubitus interruptus (Ci. Thus, FU may act as a regulator of the human counterparts of Ci, the GLI transcription factors. Since Ci and GLI are targets of Hedgehog signaling in development and morphogenesis, it is expected that FU plays an important role in Sonic, Desert and/or Indian Hedgehog induced cellular signaling. Results The FU gene was identified on chromosome 2q35 at 217.56 Mb and its exon-intron organization determined. The human developmental disorder Syndactyly type 1 (SD1 maps to this region on chromosome 2 and the FU coding region was sequenced using genomic DNA from an affected individual in a linked family. While no FU mutations were found, three single nucleotide polymorphisms were identified. The expression pattern of FU was thoroughly investigated and all examined tissues express FU. It is also clear that different tissues express transcripts of different sizes and some tissues express more than one transcript. By means of nested PCR of specific regions in RT/PCR generated cDNA, it was possible to verify two alternative splicing events. This also suggests the existence of at least two additional protein isoforms besides the FU protein that has previously been described. This long FU and a much shorter isoform were compared for the ability to regulate GLI1 and GLI2. None of the FU isoforms showed any effects on GLI1 induced transcription but the long form can enhance GLI2 activity. Apparently FU did not have any effect on SUFU induced inhibition of GLI. Conclusions The FU gene and its genomic structure was identified. FU is a candidate gene for SD1, but we have not identified a pathogenic mutation in the FU coding region in a family with SD1. The sequence information and expression analyses show that transcripts of different sizes are expressed and subjected to alternative splicing

  1. Functional differences between L- and T-plastin isoforms

    OpenAIRE

    1994-01-01

    Fimbrins/plastins are a family of highly conserved actin-bundling proteins. They are present in all eukaryotic cells including yeast, but each isoform displays a remarkable tissue specificity. T-plastin is normally found in epithelial and mesenchymal cells while L-plastin is present in hematopoietic cells. However, L-plastin has been also found in tumor cells of non-hematopoietic origin (Lin, C.-S., R. H. Aebersold, S. B. Kent, M. Varma, and J. Leavitt. 1988. Mol. Cell. Biol. 8:4659-4668; Lin...

  2. Soluble malate dehydrogenase of Geophagus brasiliensis (Cichlidae, Perciformes: isolated isoforms and kinetics properties

    Directory of Open Access Journals (Sweden)

    Maria Regina de Aquino-Silva

    2008-01-01

    Full Text Available Kinetic properties and thermal stabilities of Geophagus brasiliensis skeletal muscle unfractionated malate dehydrogenase (MDH, EC 1.1.1.37 and its isolated isoforms were analyzed to examine a possible sMDH-B* locus duplication in a fixation process influenced by genetic drift. Two optimal pHs were detected: 7.5 for AB1 unfractionated muscle phenotype and its B1 isoform, and 8.0 for AB1B2 unfractionated muscle phenotype, A and B2 isoforms. While G. brasiliensis A isoform could be characterized as thermostable, the duplicated B isoform cannot be assumed as thermolabile. Km values for isolated B2 isoforms were 1.6 times lower than for B1. A duplication event in progress best explains the electrophoretic six-band pattern detected in G. brasiliensis, which would be caused by genetic drift.

  3. Induction of Chemokine Expression by Adiponectin In Vitro is Isoform-Dependent

    OpenAIRE

    Song, Huijuan; Chan, James; Rovin, Brad H.

    2009-01-01

    Adiponectin is reported to have both pro- and anti-inflammatory effects. Because adiponectin circulates in isoforms of various sizes, and some responses to adiponectin are isoform-dependent, it was postulated that the pro-inflammatory effects of adiponectin may isoform-specific. To test this, peripheral blood mononuclear cells (PBMC), microvascular endothelial cells (MVEC), and human glomerular mesangial cells (HMC) were treated with high or low molecular weight (HMW, LMW) recombinant human a...

  4. MetaDiff: differential isoform expression analysis using random-effects meta-regression

    OpenAIRE

    Jia, Cheng; Guan, Weihua; Yang, Amy; Xiao, Rui; Tang, W. H. Wilson; Moravec, Christine S.; Margulies, Kenneth B.; Cappola, Thomas P.; Li, Mingyao; Li, Chun

    2015-01-01

    Background RNA sequencing (RNA-Seq) allows an unbiased survey of the entire transcriptome in a high-throughput manner. A major application of RNA-Seq is to detect differential isoform expression across experimental conditions, which is of great biological interest due to its direct relevance to protein function and disease pathogenesis. Detection of differential isoform expression is challenging because of uncertainty in isoform expression estimation owing to ambiguous reads and variability i...

  5. Selective glucocorticoid receptor translational isoforms reveal glucocorticoid-induced apoptotic transcriptomes

    OpenAIRE

    Wu, I; Shin, S. C.; Cao, Y; Bender, I K; N Jafari; Feng, G.; Lin, S.; Cidlowski, J. A.; Schleimer, R. P.; Lu, N Z

    2013-01-01

    Induction of T-cell apoptosis contributes to the anti-inflammatory and antineoplastic benefits of glucocorticoids. The glucocorticoid receptor (GR) translational isoforms have distinct proapoptotic activities in osteosarcoma cells. Here we determined whether GR isoforms selectively induce apoptosis in Jurkat T lymphoblastic leukemia cells. Jurkat cells stably expressing individual GR isoforms were generated and treated with vehicle or dexamethasone (DEX). DEX induced apoptosis in cells expres...

  6. IsoformEx: isoform level gene expression estimation using weighted non-negative least squares from mRNA-Seq data

    Directory of Open Access Journals (Sweden)

    Gupta Ravi

    2011-07-01

    Full Text Available Abstract Background mRNA-Seq technology has revolutionized the field of transcriptomics for identification and quantification of gene transcripts not only at gene level but also at isoform level. Estimating the expression levels of transcript isoforms from mRNA-Seq data is a challenging problem due to the presence of constitutive exons. Results We propose a novel algorithm (IsoformEx that employs weighted non-negative least squares estimation method to estimate the expression levels of transcript isoforms. Validations based on in silico simulation of mRNA-Seq and qRT-PCR experiments with real mRNA-Seq data showed that IsoformEx could accurately estimate transcript expression levels. In comparisons with published methods, the transcript expression levels estimated by IsoformEx showed higher correlation with known transcript expression levels from simulated mRNA-Seq data, and higher agreement with qRT-PCR measurements of specific transcripts for real mRNA-Seq data. Conclusions IsoformEx is a fast and accurate algorithm to estimate transcript expression levels and gene expression levels, which takes into account short exons and alternative exons with a weighting scheme. The software is available at http://bioinformatics.wistar.upenn.edu/isoformex.

  7. Prostaglandin D Synthase Isoforms from Cerebrospinal Fluid Vary with Brain Pathology

    Directory of Open Access Journals (Sweden)

    Michael G. Harrington

    2006-01-01

    Full Text Available Glutathione independent prostaglandin D synthase (Swissprot P41222, PTGDS has been identified in human cerebrospinal fluid and some changes in PTGDS in relation to disease have been reported. However, little is known of the extent that PTGDS isoforms fluctuate across a large range of congenital and acquired diseases. The purpose of this study was to examine changes in PTGDS isoforms in such a population. Spinal fluid from 22 healthy study participants (normal controls with no classifiable neurological or psychiatric diagnosis was obtained and PTGDS isoforms were identified by specific immunostaining and mass spectrometry after denaturing 2D gel electrophoresis. The PTGDS isoforms in controls consisted of five charge isoforms that were always present and a small number of occasional, low abundance isoforms. A qualitative survey of 98 different people with a wide range of congenital and acquired diseases revealed striking changes. Loss of the control isoforms occurred in congenital malformations of the nervous system. Gain of additional isoforms occurred in some degenerative, most demyelinating and vasculitic diseases, as well as in Creutzfeldt-Jakob disease. A retrospective analysis of published data that quantified relative amounts of PTGDS in multiple sclerosis, schizophrenia and Parkinson’s disease compared to controls revealed significant dysregulation. It is concluded that qualitative and quantitative fluctuations of cerebrospinal fluid PTGDS isoforms reflect both major and subtle brain pathophysiology.

  8. Proteomic Analysis of Cytokeratin Isoforms Uncovers Association with Survival in Lung Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Tarek G. Gharib

    2002-01-01

    Full Text Available Cytokeratins. (CK are intermediate filaments whose expression is often altered in epithelial cancer. Systematic identification of lung adenocarcinoma proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry has uncovered numerous CK isoforms. In this study, 93 lung adenocarcinomas. (64 stage I and 29 stage III and 10 uninvolved lung samples were quantitatively examined for protein expression. Fourteen of 21 isoforms of CK 7, 8, 18, 19 occurred at significantly higher levels. (P<.05 in tumors compared to uninvolved adjacent tissue. Specific isoforms of the four types of CK identified correlated with either clinical outcome or individual clinical-pathological parameters. All five of the CK7 isoforms associated with patient survival represented cleavage products. Two of five CK7 isoforms. (nos. 2165 and 2091, one of eight CK8 isoforms. (no. 439, one of three CK19 isoforms. (no. 1955 were associated with survival and significantly correlated to their mRNA levels, suggesting that transcription underlies overexpression of these CK isoforms. Our data indicate substantial heterogeneity among CK in lung adenocarcinomas resulting from posttranslational modifications, some of which correlated with patient survival and other clinical parameters. Therefore, specific isoforms of individual CK may have utility as diagnostic or predictive markers in lung adenocarcinomas.

  9. Entropy-based model for miRNA isoform analysis.

    Directory of Open Access Journals (Sweden)

    Shengqin Wang

    Full Text Available MiRNAs have been widely studied due to their important post-transcriptional regulatory roles in gene expression. Many reports have demonstrated the evidence of miRNA isoform products (isomiRs in high-throughput small RNA sequencing data. However, the biological function involved in these molecules is still not well investigated. Here, we developed a Shannon entropy-based model to estimate isomiR expression profiles of high-throughput small RNA sequencing data extracted from miRBase webserver. By using the Kolmogorov-Smirnov statistical test (KS test, we demonstrated that the 5p and 3p miRNAs present more variants than the single arm miRNAs. We also found that the isomiR variant, except the 3' isomiR variant, is strongly correlated with Minimum Free Energy (MFE of pre-miRNA, suggesting the intrinsic feature of pre-miRNA should be one of the important factors for the miRNA regulation. The functional enrichment analysis showed that the miRNAs with high variation, particularly the 5' end variation, are enriched in a set of critical functions, supporting these molecules should not be randomly produced. Our results provide a probabilistic framework for miRNA isoforms analysis, and give functional insights into pre-miRNA processing.

  10. A New View of Ras Isoforms in Cancers.

    Science.gov (United States)

    Nussinov, Ruth; Tsai, Chung-Jung; Chakrabarti, Mayukh; Jang, Hyunbum

    2016-01-01

    Does small GTPase K-Ras4A have a single state or two states, one resembling K-Ras4B and the other N-Ras? A recent study of K-Ras4A made the remarkable observation that even in the absence of the palmitoyl, K-Ras4A can be active at the plasma membrane. Importantly, this suggests that K-Ras4A may exist in two distinct signaling states. In state 1, K-Ras4A is only farnesylated, like K-Ras4B; in state 2, farnesylated and palmitoylated, like N-Ras. The K-Ras4A hypervariable region sequence is positively charged, in between K-Ras4B and N-Ras. Taken together, this raises the possibility that the farnesylated but nonpalmitoylated state 1, like K-Ras4B, binds calmodulin and is associated with colorectal and other adenocarcinomas like lung cancer and pancreatic ductal adenocarcinoma. On the other hand, state 2 may be associated with melanoma and other cancers where N-Ras is a major contributor, such as acute myeloid leukemia. Importantly, H-Ras has two, singly and doubly, palmitoylated states that may also serve distinct functional roles. The multiple signaling states of palmitoylated Ras isoforms question the completeness of small GTPase Ras isoform statistics in different cancer types and call for reevaluation of concepts and protocols. They may also call for reconsideration of oncogenic Ras therapeutics. PMID:26659836

  11. A Review of Metallothionein Isoforms and their Role in Pathophysiology

    Directory of Open Access Journals (Sweden)

    Senthil kumar M

    2011-05-01

    Full Text Available Abstract The Metallothionein (MT is a protein which has several interesting biological effects and has been demonstrated increase focus on the role of MT in various biological systems in the past three decades. The studies on the role of MT were limited with few areas like apoptosis and antioxidants in selected organs even fifty years after its discovery. Now acknowledge the exploration of various isoforms of MT such as MT-I, MT-II, MT-III and MT-IV and other isoforms in various biological systems. Strong evidence exists that MT modulates complex diseases and the immune system in the body but the primary function of MT still remains unknown. This review's main objective is to explore the capability to specifically manipulate MT levels in cells and in animals to provide answers regarding how MT could impact those complex disease scenarios. The experimental result mentioned in this review related among MT, zinc, cadmium, diabetic, heart disease, bone retardation, neuro toxicity, kidney dysfunction, cancer, and brain suggest novel method for exploration and contribute significantly to the growing scientist to research further in this field.

  12. Structures of alternatively spliced isoforms of human ketohexokinase.

    Science.gov (United States)

    Trinh, Chi H; Asipu, Aruna; Bonthron, David T; Phillips, Simon E V

    2009-03-01

    A molecular understanding of the unique aspects of dietary fructose metabolism may be the key to understanding and controlling the current epidemic of fructose-related obesity, diabetes and related adverse metabolic states in Western populations. Fructose catabolism is initiated by its phosphorylation to fructose 1-phosphate, which is performed by ketohexokinase (KHK). Here, the crystal structures of the two alternatively spliced isoforms of human ketohexokinase, hepatic KHK-C and the peripheral isoform KHK-A, and of the ternary complex of KHK-A with the substrate fructose and AMP-PNP are reported. The structure of the KHK-A ternary complex revealed an active site with both the substrate fructose and the ATP analogue in positions ready for phosphorylation following a reaction mechanism similar to that of the pfkB family of carbohydrate kinases. Hepatic KHK deficiency causes the benign disorder essential fructosuria. The effects of the disease-causing mutations (Gly40Arg and Ala43Thr) have been modelled in the context of the KHK structure.

  13. Interaction of Carthamus tinctorius lignan arctigenin with the binding site of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase.

    Science.gov (United States)

    Temml, Veronika; Kuehnl, Susanne; Schuster, Daniela; Schwaiger, Stefan; Stuppner, Hermann; Fuchs, Dietmar

    2013-01-01

    Mediterranean Carthamus tinctorius (Safflower) is used for treatment of inflammatory conditions and neuropsychiatric disorders. Recently C. tinctorius lignans arctigenin and trachelogenin but not matairesinol were described to interfere with the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) in peripheral blood mononuclear cells in vitro. We examined a potential direct influence of compounds on IDO enzyme activity applying computational calculations based on 3D geometry of the compounds. The interaction pattern analysis and force field-based minimization was performed within LigandScout 3.03, the docking simulation with MOE 2011.10 using the X-ray crystal structure of IDO. Results confirm the possibility of an intense interaction of arctigenin and trachelogenin with the binding site of the enzyme, while matairesinol had no such effect. PMID:24251110

  14. Indoleamine 2,3-dioxygenase 1 (ido1 is involved in the control of mouse caput epididymis immune environment.

    Directory of Open Access Journals (Sweden)

    Aicha Jrad-Lamine

    Full Text Available The epididymis maintains a state of immune tolerance towards spermatozoa while also protecting them and itself against infection and acute inflammation. The immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (Ido1 participates in this delicate local equilibrium. Using the mouse Ido1(-/- model, we show here that the absence of IDO1 expression leads in the epididymis but not in serum to (1 an increase in the inflammatory state as evidenced by changes in the content of cytokines and chemokines, (2 the engagement of a Th1-driven inflammatory response as evidenced by changes in the Th17/Treg as well as Th1/Th2 equilibria, as well as (3 differences in the content of lipid intermediates classically involved in inflammation. Despite this more pronounced inflammatory state, Ido1(-/- animals succeed in preserving the local epididymal immune situation due to the activation of compensatory mechanisms that are discussed.

  15. Indoleamine 2,3-dioxygenase 1 (ido1) is involved in the control of mouse caput epididymis immune environment.

    Science.gov (United States)

    Jrad-Lamine, Aicha; Henry-Berger, Joelle; Damon-Soubeyrand, Christelle; Saez, Fabrice; Kocer, Ayhan; Janny, Laurent; Pons-Rejraji, Hanae; Munn, David H; Mellor, Andrew L; Gharbi, Najoua; Cadet, Rémi; Guiton, Rachel; Aitken, Robert J; Drevet, Joël R

    2013-01-01

    The epididymis maintains a state of immune tolerance towards spermatozoa while also protecting them and itself against infection and acute inflammation. The immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (Ido1) participates in this delicate local equilibrium. Using the mouse Ido1(-/-) model, we show here that the absence of IDO1 expression leads in the epididymis but not in serum to (1) an increase in the inflammatory state as evidenced by changes in the content of cytokines and chemokines, (2) the engagement of a Th1-driven inflammatory response as evidenced by changes in the Th17/Treg as well as Th1/Th2 equilibria, as well as (3) differences in the content of lipid intermediates classically involved in inflammation. Despite this more pronounced inflammatory state, Ido1(-/-) animals succeed in preserving the local epididymal immune situation due to the activation of compensatory mechanisms that are discussed. PMID:23840489

  16. Molecular modeling of 2-nitropropane dioxygenase domain of Mycobacterium tuberculosis H37Rv and docking of herbal ligands.

    Science.gov (United States)

    Ramesh, K V; Akhila, B N; Deshmukh, Sudha

    2011-06-01

    The 3D structure of enoyl reductase (ER) domain generated by the SWISS MODEL server contains the 2-nitropropane dioxygenase (2NPD) structure displaying the TIM barrel fold. Though TIM barrel fold is made up of both main and inserted domains, in our study, we could only predict the structure of the main domain, which had central barrel of eight beta-strands surrounded by eight alpha-helices. Superimposition of the 2NPD region of ER domain of Mycobacterium tuberculosis H37Rv on to the corresponding region of 2UVA_G revealed a good structural alignment between the two, suggesting this template to be a good structural homologue. Among various herbal ligands that were screened as inhibitors, daucosterol was found to bind in closest proximity to the flavin mono nucleotide (FMN) binding site with the lowest docking energy. PMID:21793307

  17. Localization of the human indoleamine 2,3-dioxygenase (IDO) gene to the pericentromeric region of human chromosome 8

    Energy Technology Data Exchange (ETDEWEB)

    Burkin, D.J.; Jones, C. (Eleanor Roosevelt Institute for Cancer Research, Denver, CO (United States)); Kimbro, K.S.; Taylor, M.W. (Indiana Univ., Bloomington, IN (United States)); Barr, B.L.; Gupta, S.L. (Hipple Cancer Research Center, Dayton, OH (United States))

    1993-07-01

    Indoleamine 2,3-dioxygenase (IDO) is the first enzyme in the catabolic pathway for tryptophan. This extrahepatic enzyme differs from the hepatic enzyme, tryptophan 2,3-dioxygenase (TDO), in molecular as well as enzymatic characteristics, although both enzymes catalyze the same reaction: cleavage of tryptophan into N-formylkynurenine. The induction of IDO by IFN-[gamma] plays a role in the antigrowth effect of IFN-[gamma] in cell cultures and in the inhibition of intracellular pathogens, e.g., Toxoplasma gondii and Chlamydia psittaci. Tryptophan is also the precursor for the synthesis of serotonin, and reduced levels of tryptophan and serotonin found in AIDS patients have been correlated with the presence of IFN-[gamma] and consequent elevation of IDO activity. The IDO enzyme has been purified and characterized, and its cDNA and genomic DNA clones have been isolated and analyzed. DNA from hybrid cells containing fragments of human chromosome 8 was used to determine the regional localization of the IDO gene on chromosome 8. The hybrids R30-5B and R30-2A contain 8p11 [yields] qter and 8q13 [yields] qter, respectively. Hybrid 229-3A contains the 8pter [yields] q11. The hybrid R30-2A was negative for the IDO gene, whereas R30-5B and 229-3A were positive as analyzed by PCR and verified by Southern blotting. Only the region close to the centromere is shared by R30-5B and 229-3A hybrids. The results indicate that the IDO gene is located on chromosome 8p11 [yields] q11.

  18. Redox proteins of hydroxylating bacterial dioxygenases establish a regulatory cascade that prevents gratuitous induction of tetralin biodegradation genes.

    Science.gov (United States)

    Ledesma-García, Laura; Sánchez-Azqueta, Ana; Medina, Milagros; Reyes-Ramírez, Francisca; Santero, Eduardo

    2016-01-01

    Bacterial dioxygenase systems are multicomponent enzymes that catalyze the initial degradation of many environmentally hazardous compounds. In Sphingopyxis granuli strain TFA tetralin dioxygenase hydroxylates tetralin, an organic contaminant. It consists of a ferredoxin reductase (ThnA4), a ferredoxin (ThnA3) and a oxygenase (ThnA1/ThnA2), forming a NAD(P)H-ThnA4-ThnA3-ThnA1/ThnA2 electron transport chain. ThnA3 has also a regulatory function since it prevents expression of tetralin degradation genes (thn) in the presence of non-metabolizable substrates of the catabolic pathway. This role is of physiological relevance since avoids gratuitous and wasteful production of catabolic enzymes. Our hypothesis for thn regulation implies that ThnA3 exerts its action by diverting electrons towards the regulator ThnY, an iron-sulfur flavoprotein that together with the transcriptional activator ThnR is necessary for thn gene expression. Here we analyze electron transfer among ThnA4, ThnA3 and ThnY by using stopped-flow spectrophotometry and determination of midpoint reduction potentials. Our results indicate that when accumulated in its reduced form ThnA3 is able to fully reduce ThnY. In addition, we have reproduced in vitro the regulatory circuit in the proposed physiological direction, NAD(P)H-ThnA4-ThnA3-ThnY. ThnA3 represents an unprecedented way of communication between a catabolic pathway and its regulatory system to prevent gratuitous induction. PMID:27030382

  19. Properties of catechol 1,2-dioxygenase in the cell free extract and immobilized extract of Mycobacterium fortuitum

    Directory of Open Access Journals (Sweden)

    A.S. Silva

    2013-01-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAH are carcinogenic compounds which contaminate water and soil, and the enzymes can be used for bioremediation of these environments. This study aimed to evaluate some environmental conditions that affect the production and activity of the catechol 1,2-dioxygenase (C12O by Mycobacterium fortuitum in the cell free and immobilized extract in sodium alginate. The bacterium was grown in mineral medium and LB broth containing 250 mg L-1 of anthracene (PAH. The optimum conditions of pH (4.0-9.0, temperature (5-70 ºC, reaction time (10-90 min and the effect of ions in the enzyme activity were determined. The Mycobacterium cultivated in LB shown higher growth and the C12O activity was two-fold higher to that in the mineral medium. To both extracts the highest enzyme activity was at pH 8.0, however, the immobilized extract promoted the increase in the C12O activity in a pH range between 4.0 and 8.5. The immobilized extract increased the enzymatic activity time and showed the highest C12O activity at 45 ºC, 20 ºC higher than the greatest temperature in the cell free extract. The enzyme activity in both extracts was stimulated by Fe3+, Hg2+ and Mn2+ and inhibited by NH4+ and Cu2+, but the immobilization protected the enzyme against the deleterious effects of K+ and Mg2+ in tested concentrations. The catechol 1,2-dioxygenase of Mycobacterium fortuitum in the immobilized extract has greater stability to the variations of pH, temperature and reaction time, and show higher activity in presence of ions, comparing to the cell free extract.

  20. In situ, real-time catabolic gene expression: Extraction and characterization of naphthalene dioxygenase mRNA transcripts from groundwater

    International Nuclear Information System (INIS)

    The authors developed procedures for isolating and characterizing in situ-transcribed mRNA from groundwater microorganisms catabolizing naphthalene at a coal tar waste-contaminated site. Groundwater was pumped through 0.22-microm-pore-size filters, which were then frozen to dry ice-ethanol. RNA was extracted from the frozen filters by boiling sodium dodecyl sulfate lysis and acidic phenol-chloroform extraction. Transcript characterization was performed with a series of PCR primers designed to amplify nahAc homologs. Several primer pairs were found to amplify nahAc homologs representing the entire diversity of the naphthalene-degrading genes. The environmental RNA extract was reverse transcribed, and the resultant mixture of cDNAs was amplified by PCR. A digoxigenin-labeled probe mixture was produced by PCR amplification of groundwater cDNA. This probe mixture hybridized under stringent conditions with the corresponding PCR products from naphthalene-degrading bacteria carrying a variety of nahAc homologs, indicating that diverse dioxygenase transcripts had been retrieved from groundwater. Diluted and undiluted cDNA preparations were independently amplified, and 28 of the resulting PCR products were cloned and sequenced. Sequence comparisons revealed two major groups related to the dioxygenase genes ndoB and dntAc, previously cloned from Pseudomonas putida NCIB 9816-4 and Burkholderia sp. strain DNT, respectively. A distinctive subgroup of sequences was found only in experiments performed with the undiluted cDNA preparation. To the authors' knowledge, these results are the first to directly document in situ transcription of genes encoding naphthalene catabolism at a contaminated site by indigenous microorganisms. The retrieved sequences represent greater diversity than has been detected at the study site by culture-based approaches

  1. Redox proteins of hydroxylating bacterial dioxygenases establish a regulatory cascade that prevents gratuitous induction of tetralin biodegradation genes

    Science.gov (United States)

    Ledesma-García, Laura; Sánchez-Azqueta, Ana; Medina, Milagros; Reyes-Ramírez, Francisca; Santero, Eduardo

    2016-01-01

    Bacterial dioxygenase systems are multicomponent enzymes that catalyze the initial degradation of many environmentally hazardous compounds. In Sphingopyxis granuli strain TFA tetralin dioxygenase hydroxylates tetralin, an organic contaminant. It consists of a ferredoxin reductase (ThnA4), a ferredoxin (ThnA3) and a oxygenase (ThnA1/ThnA2), forming a NAD(P)H–ThnA4–ThnA3–ThnA1/ThnA2 electron transport chain. ThnA3 has also a regulatory function since it prevents expression of tetralin degradation genes (thn) in the presence of non-metabolizable substrates of the catabolic pathway. This role is of physiological relevance since avoids gratuitous and wasteful production of catabolic enzymes. Our hypothesis for thn regulation implies that ThnA3 exerts its action by diverting electrons towards the regulator ThnY, an iron-sulfur flavoprotein that together with the transcriptional activator ThnR is necessary for thn gene expression. Here we analyze electron transfer among ThnA4, ThnA3 and ThnY by using stopped-flow spectrophotometry and determination of midpoint reduction potentials. Our results indicate that when accumulated in its reduced form ThnA3 is able to fully reduce ThnY. In addition, we have reproduced in vitro the regulatory circuit in the proposed physiological direction, NAD(P)H–ThnA4–ThnA3–ThnY. ThnA3 represents an unprecedented way of communication between a catabolic pathway and its regulatory system to prevent gratuitous induction. PMID:27030382

  2. Differential sensitivity of rat voltage-sensitive sodium channel isoforms to pyrazoline-type insecticides.

    Science.gov (United States)

    Silver, Kristopher S; Soderlund, David M

    2006-07-15

    Pyrazoline-type insecticides are potent inhibitors of insect and mammalian voltage-sensitive sodium channels. In mammals, there are nine sodium channel alpha subunit isoforms that have unique distributions and pharmacological properties, but no published data exist that compare the relative sensitivity of these different mammalian sodium channel isoforms to inhibition by pyrazoline-type insecticides. This study employed the Xenopus oocyte expression system to examine the relative sensitivity of rat Na(v)1.2a, Na(v)1.4, Na(v)1.5, and Na(v)1.8 sodium channel alpha subunit isoforms to the pyrazoline-type insecticides indoxacarb, DCJW, and RH 3421. Additionally, we assessed the effect of coexpression with the rat beta1 auxiliary subunit on the sensitivity of the Na(v)1.2a and Na(v)1.4 isoforms to these compounds. The relative sensitivity of the four sodium channel alpha subunits differed for each of the three compounds we examined. With DCJW, the order of sensitivity was Na(v)1.4 > Na(v)1.2a > Na(v)1.5 > Na(v)1.8. In contrast, the relative sensitivity of these isoforms to indoxacarb differed from that to DCJW: the Na(v)1.8 isoform was most sensitive, the Na(v)1.4 isoform was completely insensitive, and the sensitivities of the Na(v)1.5 and Na(v)1.2a isoforms were intermediate between these two extremes. Moreover, the pattern of sensitivity to RH 3421 among these four isoforms was different from that for either indoxacarb or DCJW: the Na(v)1.4 isoform was most sensitive to RH 3421, whereas the sensitivities of the remaining three isoforms were substantially less than that of the Na(v)1.4 isoform and were approximately equivalent. The only statistically significant effect of coexpression of either the Na(v)1.2a or Na(v)1.4 isoforms with the beta1 subunit was the modest reduction in the sensitivity of the Na(v)1.2a isoform to RH 3421. These results demonstrate that mammalian sodium channel isoforms differ in their sensitivities to pyrazoline-type insecticides.

  3. Expression of phosphoinositide-specific phospholipase C isoforms in native endothelial cells.

    Directory of Open Access Journals (Sweden)

    Delphine M Béziau

    Full Text Available Phospholipase C (PLC comprises a superfamily of enzymes that play a key role in a wide array of intracellular signalling pathways, including protein kinase C and intracellular calcium. Thirteen different mammalian PLC isoforms have been identified and classified into 6 families (PLC-β, γ, δ, ε, ζ and η based on their biochemical properties. Although the expression of PLC isoforms is tissue-specific, concomitant expression of different PLC has been reported, suggesting that PLC family is involved in multiple cellular functions. Despite their critical role, the PLC isoforms expressed in native endothelial cells (ECs remains undetermined. A conventional PCR approach was initially used to elucidate the mRNA expression pattern of PLC isoforms in 3 distinct murine vascular beds: mesenteric (MA, pulmonary (PA and middle cerebral arteries (MCA. mRNA encoding for most PLC isoforms was detected in MA, MCA and PA with the exception of η2 and β2 (only expressed in PA, δ4 (only expressed in MCA, η1 (expressed in all but MA and ζ (not detected in any vascular beds tested. The endothelial-specific PLC expression was then sought in freshly isolated ECs. Interestingly, the PLC expression profile appears to differ across the investigated arterial beds. While mRNA for 8 of the 13 PLC isoforms was detected in ECs from MA, two additional PLC isoforms were detected in ECs from PA and MCA. Co-expression of multiple PLC isoforms in ECs suggests an elaborate network of signalling pathways: PLC isoforms may contribute to the complexity or diversity of signalling by their selective localization in cellular microdomains. However in situ immunofluorescence revealed a homogeneous distribution for all PLC isoforms probed (β3, γ2 and δ1 in intact endothelium. Although PLC isoforms play a crucial role in endothelial signal transduction, subcellular localization alone does not appear to be sufficient to determine the role of PLC in the signalling microdomains found

  4. Nesprins: tissue-specific expression of epsilon and other short isoforms.

    Directory of Open Access Journals (Sweden)

    Nguyen Thuy Duong

    Full Text Available Nesprin-1-giant and nesprin-2-giant regulate nuclear positioning by the interaction of their C-terminal KASH domains with nuclear membrane SUN proteins and their N-terminal calponin-homology domains with cytoskeletal actin. A number of short isoforms lacking the actin-binding domains are produced by internal promotion. We have evaluated the significance of these shorter isoforms using quantitative RT-PCR and western blotting with site-specific monoclonal antibodies. Within a complete map of nesprin isoforms, we describe two novel nesprin-2 epsilon isoforms for the first time. Epsilon isoforms are similar in size and structure to nesprin-1-alpha. Expression of nesprin isoforms was highly tissue-dependent. Nesprin-2-epsilon-1 was found in early embryonic cells, while nesprin-2-epsilon-2 was present in heart and other adult tissues, but not skeletal muscle. Some cell lines lack shorter isoforms and express only one of the two nesprin genes, suggesting that either of the giant nesprins is sufficient for basic cell functions. For the first time, localisation of endogenous nesprin away from the nuclear membrane was shown in cells where removal of the KASH domain by alternative splicing occurs. By distinguishing between degradation products and true isoforms on western blots, it was found that previously-described beta and gamma isoforms are expressed either at only low levels or with a limited tissue distribution. Two of the shortest alpha isoforms, nesprin-1-alpha-2 and nesprin-2-alpha-1, were found almost exclusively in cardiac and skeletal muscle and a highly conserved and alternatively-spliced exon, available in both nesprin genes, was always included in these tissues. These "muscle-specific" isoforms are thought to form a complex with emerin and lamin A/C at the inner nuclear membrane and mutations in all three proteins cause Emery-Dreifuss muscular dystrophy and/or inherited dilated cardiomyopathy, disorders in which only skeletal muscle and

  5. Different phosphoinositide 3-kinase isoforms mediate carrageenan nociception and inflammation.

    Science.gov (United States)

    Pritchard, Rory A; Falk, Lovissa; Larsson, Mathilda; Leinders, Mathias; Sorkin, Linda S

    2016-01-01

    Phosphoinositide 3-kinases (PI3Ks) participate in signal transduction cascades that can directly activate and sensitize nociceptors and enhance pain transmission. They also play essential roles in chemotaxis and immune cell infiltration leading to inflammation. We wished to determine which PI3K isoforms were involved in each of these processes. Lightly anesthetized rats (isoflurane) were injected subcutaneously with carrageenan in their hind paws. This was preceded by a local injection of 1% DMSO vehicle or an isoform-specific antagonist to PI3K-α (compound 15-e), -β (TGX221), -δ (Cal-101), or -γ (AS252424). We measured changes in the mechanical pain threshold and spinal c-Fos expression (4 hours after injection) as indices of nociception. Paw volume, plasma extravasation (Evans blue, 0.3 hours after injection), and neutrophil (myeloperoxidase; 1 hour after injection) and macrophage (CD11b+; 4 hour after injection) infiltration into paw tissue were the measured inflammation endpoints. Only PI3K-γ antagonist before treatment reduced the carrageenan-induced pain behavior and spinal expression of c-Fos (P ≤ 0.01). In contrast, pretreatment with PI3K-α, -δ, and-γ antagonists reduced early indices of inflammation. Plasma extravasation PI3K-α (P ≤ 0.05), -δ (P ≤ 0.05), and -γ (P ≤ 0.01), early (0-2 hour) edema -α (P ≤ 0.05), -δ (P ≤ 0.001), and -γ (P ≤ 0.05), and neutrophil infiltration (all P ≤ 0.001) were all reduced compared to vehicle pretreatment. Later (2-4 hour), edema and macrophage infiltration (P ≤ 0.05) were reduced by only the PI3K-δ and -γ isoform antagonists, with the PI3K-δ antagonist having a greater effect on edema. PI3K-β antagonism was ineffective in all paradigms. These data indicate that pain and clinical inflammation are pharmacologically separable and may help to explain clinical conditions in which inflammation naturally wanes or goes into remission, but pain continues unabated.

  6. Glial fibrillary acidic protein isoform expression in plaque related astrogliosis in Alzheimer's disease.

    Science.gov (United States)

    Kamphuis, Willem; Middeldorp, Jinte; Kooijman, Lieneke; Sluijs, Jacqueline A; Kooi, Evert-Jan; Moeton, Martina; Freriks, Michel; Mizee, Mark R; Hol, Elly M

    2014-03-01

    In Alzheimer's disease (AD), amyloid plaques are surrounded by reactive astrocytes with an increased expression of intermediate filaments including glial fibrillary acidic protein (GFAP). Different GFAP isoforms have been identified that are differentially expressed by specific subpopulations of astrocytes and that impose different properties to the intermediate filament network. We studied transcript levels and protein expression patterns of all known GFAP isoforms in human hippocampal AD tissue at different stages of the disease. Ten different transcripts for GFAP isoforms were detected at different abundancies. Transcript levels of most isoforms increased with AD progression. GFAPδ-immunopositive astrocytes were observed in subgranular zone, hilus, and stratum-lacunosum-moleculare. GFAPδ-positive cells also stained for GFAPα. In AD donors, astrocytes near plaques displayed increased staining of both GFAPα and GFAPδ. The reading-frame-shifted isoform, GFAP(+1), staining was confined to a subset of astrocytes with long processes, and their number increased in the course of AD. In conclusion, the various GFAP isoforms show differential transcript levels and are upregulated in a concerted manner in AD. The GFAP(+1) isoform defines a unique subset of astrocytes, with numbers increasing with AD progression. These data indicate the need for future exploration of underlying mechanisms concerning the functions of GFAPδ and GFAP(+1) isoforms in astrocytes and their possible role in AD pathology.

  7. Activation of AMPK alpha and gamma-isoform complexes in the intact ischemic rat heart

    Science.gov (United States)

    AMP-activated protein kinase (AMPK) plays a key role in modulating cellular metabolic processes. AMPK, a serine-threonine kinase, is a heterotrimeric complex of catalytic alpha-subunits and regulatory beta- and gamma-subunits with multiple isoforms. Mutations in the cardiac gamma(2)-isoform have bee...

  8. Comprehensive analysis of tropomyosin isoforms in skeletal muscles by top-down proteomics.

    Science.gov (United States)

    Jin, Yutong; Peng, Ying; Lin, Ziqing; Chen, Yi-Chen; Wei, Liming; Hacker, Timothy A; Larsson, Lars; Ge, Ying

    2016-04-01

    Mammalian skeletal muscles are heterogeneous in nature and are capable of performing various functions. Tropomyosin (Tpm) is a major component of the thin filament in skeletal muscles and plays an important role in controlling muscle contraction and relaxation. Tpm is known to consist of multiple isoforms resulting from different encoding genes and alternative splicing, along with post-translational modifications. However, a systematic characterization of Tpm isoforms in skeletal muscles is still lacking. Therefore, we employed top-down mass spectrometry (MS) to identify and characterize Tpm isoforms present in different skeletal muscles from multiple species, including swine, rat, and human. Our study revealed that Tpm1.1 and Tpm2.2 are the two major Tpm isoforms in swine and rat skeletal muscles, whereas Tpm1.1, Tpm2.2, and Tpm3.12 are present in human skeletal muscles. Tandem MS was utilized to identify the sequences of the major Tpm isoforms. Furthermore, quantitative analysis revealed muscle-type specific differences in the abundance of un-modified and modified Tpm isoforms in rat and human skeletal muscles. This study represents the first systematic investigation of Tpm isoforms in skeletal muscles, which not only demonstrates the capabilities of top-down MS for the comprehensive characterization of skeletal myofilament proteins but also provides the basis for further studies on these Tpm isoforms in muscle-related diseases. PMID:27090236

  9. Molecular cloning and pharmacology of functionally distinct isoforms of the human histamine H(3) receptor

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Goodman, M W; Burstein, E S;

    2002-01-01

    The pharmacology of histamine H(3) receptors suggests the presence of distinct receptor isoforms or subtypes. We herein describe multiple, functionally distinct, alternatively spliced isoforms of the human H(3) receptor. Combinatorial splicing at three different sites creates at least six distinc...

  10. Activation of antithrombin III isoforms by heparan sulphate glycosaminoglycans and other sulphated polysaccharides.

    Science.gov (United States)

    Carlson, T H; Kolman, M R; Piepkorn, M

    1995-07-01

    Antithrombin III occurs naturally as two functionally distinct molecular species that differ in glycosylation at Asn135. Whereas the predominant, glycosylated isoform has high affinity for heparin, a quantitatively minor isoform lacking glycosylation at that site displays relatively higher affinity for both heparins and heparinoids. We characterized the ability of various sulphated polysaccharides to potentiate the rates of thrombin inhibition by the isoforms. High-molecular-weight dextran sulphate was the most effective of those studied, increasing thrombin inhibition by the higher-affinity antithrombin III isoform up to five-fold more efficiently than did heparin fractions with low-affinity for antithrombin III. In addition, dextran sulphate activated the higher-affinity isoform as much as twelve times more effectively than it did the lower-affinity isoform. Pentosan polysulphate was up to three-fold, and some heparan sulphate fractions up to two-fold, more effective with the higher, compared with the lower affinity, isoform. Heparan sulphate preparations less effectively increased the rate of thrombin inhibition than did the other low-affinity polysaccharides. Structure-function studies indicated positive correlations between activity and both polymer length and anionic group density of low-affinity sulphated polysaccharides. The observed effects of the heparan sulphates on this anticoagulant pathway, although of low potency, are consistent with the hypotheses that these substances naturally regulate blood homeostasis in vascular tissues and that much of this function may be mediated by the higher-affinity antithrombin III isoform. PMID:8589216

  11. Roles of the troponin isoforms during indirect flight muscle development in Drosophila

    Indian Academy of Sciences (India)

    Salam Herojeet Singh; Prabodh Kumar; Nallur B. Ramachandra; Upendra Nongthomba

    2014-08-01

    Troponin proteins in cooperative interaction with tropomyosin are responsible for controlling the contraction of the striated muscles in response to changes in the intracellular calcium concentration. Contractility of the muscle is determined by the constituent protein isoforms, and the isoforms can switch over from one form to another depending on physiological demands and pathological conditions. In Drosophila, amajority of themyofibrillar proteins in the indirect flight muscles (IFMs) undergo post-transcriptional and post-translational isoform changes during pupal to adult metamorphosis to meet the high energy and mechanical demands of flight. Using a newly generated Gal4 strain (UH3-Gal4) which is expressed exclusively in the IFMs, during later stages of development, we have looked at the developmental and functional importance of each of the troponin subunits (troponin-I, troponin-T and troponin-C) and their isoforms. We show that all the troponin subunits are required for normal myofibril assembly and flight, except for the troponin-C isoform 1 (TnC1). Moreover, rescue experiments conducted with troponin-I embryonic isoform in the IFMs, where flies were rendered flightless, show developmental and functional differences of TnI isoforms and importance of maintaining the right isoform.

  12. AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

    Science.gov (United States)

    AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE Heme oxygenase (HO) occurs in biological tissues as two major isoforms HO-1 and HO-2. HO-1 is inducible by many treatments, particularly oxidative stress-related conditions such as depletion of gl...

  13. Translational control of C/EBPalpha and C/EBPbeta isoform expression

    NARCIS (Netherlands)

    Calkhoven, C F; Müller, C; Leutz, A

    2000-01-01

    Transcription factors derived from CCAAT/enhancer binding protein (C/EBP)alpha and C/EBPbeta genes control differentiation and proliferation in a number of cell types. Various C/EBP isoforms arise from unique C/EBPbeta and C/EBPalpha mRNAs by differential initiation of translation. These isoforms re

  14. Comprehensive analysis of tropomyosin isoforms in skeletal muscles by top-down proteomics.

    Science.gov (United States)

    Jin, Yutong; Peng, Ying; Lin, Ziqing; Chen, Yi-Chen; Wei, Liming; Hacker, Timothy A; Larsson, Lars; Ge, Ying

    2016-04-01

    Mammalian skeletal muscles are heterogeneous in nature and are capable of performing various functions. Tropomyosin (Tpm) is a major component of the thin filament in skeletal muscles and plays an important role in controlling muscle contraction and relaxation. Tpm is known to consist of multiple isoforms resulting from different encoding genes and alternative splicing, along with post-translational modifications. However, a systematic characterization of Tpm isoforms in skeletal muscles is still lacking. Therefore, we employed top-down mass spectrometry (MS) to identify and characterize Tpm isoforms present in different skeletal muscles from multiple species, including swine, rat, and human. Our study revealed that Tpm1.1 and Tpm2.2 are the two major Tpm isoforms in swine and rat skeletal muscles, whereas Tpm1.1, Tpm2.2, and Tpm3.12 are present in human skeletal muscles. Tandem MS was utilized to identify the sequences of the major Tpm isoforms. Furthermore, quantitative analysis revealed muscle-type specific differences in the abundance of un-modified and modified Tpm isoforms in rat and human skeletal muscles. This study represents the first systematic investigation of Tpm isoforms in skeletal muscles, which not only demonstrates the capabilities of top-down MS for the comprehensive characterization of skeletal myofilament proteins but also provides the basis for further studies on these Tpm isoforms in muscle-related diseases.

  15. Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution

    DEFF Research Database (Denmark)

    Aachmann-Andersen, Niels Jacob; Just Christensen, Søren; Lisbjerg, Kristian;

    2014-01-01

    -acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3) % (mean (SD)). High-dose Epoetin beta decreased PMI...

  16. Differences in expression, actions and cocaine regulation of two isoforms for the brain transcriptional regulator NAC1.

    Science.gov (United States)

    Korutla, L; Wang, P J; Lewis, D M; Neustadter, J H; Stromberg, M F; Mackler, S A

    2002-01-01

    BTB/POZ proteins can influence the cell cycle and contribute to oncogenesis. Many family members are present in the mammalian CNS. Previous work demonstrated elevated NAC1 mRNA levels in the rat nucleus accumbens in response to cocaine. NAC1 acts like other BTB/POZ proteins that regulate transcription but is unusual because of the absence of identifiable DNA binding domains. cDNAs were isolated encoding two NAC1 isoforms differing by only 27 amino acids (the longer isoform contains 514 amino acids). The mRNAs for both isoforms were simultaneously expressed throughout the rat brain and peripheral tissues. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed that the mRNA of the longer isoform was more abundant than the mRNA of the shorter isoform. Western blot analysis demonstrated a similar unequal distribution between the isoforms in the CNS. The longer isoform was the more abundant of the two NAC1 proteins and the ratio between them differed throughout the rat brain. The shorter isoform was not detected in most of the examined peripheral tissues, suggesting differences from the CNS in post-transcriptional processing. Both isoforms repressed transcription in H293T cells using a Gal4-luciferase reporter system. However, the shorter isoform did not repress transcription as effectively as the longer isoform. Transfection of different ratios for both isoforms, in order to replicate the relative amounts observed throughout the CNS, supported an interaction between the isoforms. The net effect on transcriptional repression was determined by the ratio of the two NAC1 isoforms. Each isoform exhibited the subnuclear localization that is characteristic of many BTB/POZ proteins. A rapid and transient increase in the level of the shorter isoform occurred in the nucleus accumbens 2 h following a single i.p. cocaine injection. We conclude that the two isoforms of NAC1 may differentially affect neuronal functions, including the regulation of

  17. p53 isoforms regulate astrocyte-mediated neuroprotection and neurodegeneration.

    Science.gov (United States)

    Turnquist, C; Horikawa, I; Foran, E; Major, E O; Vojtesek, B; Lane, D P; Lu, X; Harris, B T; Harris, C C

    2016-09-01

    Bidirectional interactions between astrocytes and neurons have physiological roles in the central nervous system and an altered state or dysfunction of such interactions may be associated with neurodegenerative diseases, such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). Astrocytes exert structural, metabolic and functional effects on neurons, which can be either neurotoxic or neuroprotective. Their neurotoxic effect is mediated via the senescence-associated secretory phenotype (SASP) involving pro-inflammatory cytokines (e.g., IL-6), while their neuroprotective effect is attributed to neurotrophic growth factors (e.g., NGF). We here demonstrate that the p53 isoforms Δ133p53 and p53β are expressed in astrocytes and regulate their toxic and protective effects on neurons. Primary human astrocytes undergoing cellular senescence upon serial passaging in vitro showed diminished expression of Δ133p53 and increased p53β, which were attributed to the autophagic degradation and the SRSF3-mediated alternative RNA splicing, respectively. Early-passage astrocytes with Δ133p53 knockdown or p53β overexpression were induced to show SASP and to exert neurotoxicity in co-culture with neurons. Restored expression of Δ133p53 in near-senescent, otherwise neurotoxic astrocytes conferred them with neuroprotective activity through repression of SASP and induction of neurotrophic growth factors. Brain tissues from AD and ALS patients possessed increased numbers of senescent astrocytes and, like senescent astrocytes in vitro, showed decreased Δ133p53 and increased p53β expression, supporting that our in vitro findings recapitulate in vivo pathology of these neurodegenerative diseases. Our finding that Δ133p53 enhances the neuroprotective function of aged and senescent astrocytes suggests that the p53 isoforms and their regulatory mechanisms are potential targets for therapeutic intervention in neurodegenerative diseases. PMID:27104929

  18. Troponin T isoform expression is modulated during Atlantic Halibut metamorphosis

    Directory of Open Access Journals (Sweden)

    Llewellyn Lynda

    2007-06-01

    Full Text Available Abstract Background Flatfish metamorphosis is a thyroid hormone (TH driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT, a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied. Results In the present study five cDNAs for halibut TnT genes were cloned; three were splice variants arising from a single fast TnT (fTnT gene; a fourth encoded a novel teleost specific fTnT-like cDNA (AfTnT expressed exclusively in slow muscle and the fifth encoded the teleost specific sTnT2. THs modified the expression of halibut fTnT isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of TnT genes and muscle fibre organization occurred in halibut musculature. Conclusion Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

  19. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    Science.gov (United States)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  20. Exo70 Isoform Switching upon Epithelial-Mesenchymal Transition Mediates Cancer Cell Invasion

    Science.gov (United States)

    Lu, Hezhe; Liu, Jianglan; Liu, Shujing; Zeng, Jingwen; Ding, Deqiang; Carstens, Russ P.; Cong, Yusheng; Xu, Xiaowei; Guo, Wei

    2014-01-01

    Summary Epithelial-mesenchymal transition (EMT) is an important developmental process hijacked by cancer cells for their dissemination. Here we show that Exo70, a component of the exocyst complex, undergoes isoform switching mediated by ESRP1, a pre-mRNA splicing factor that regulates EMT. Expression of the epithelial isoform of Exo70 affects the levels of key EMT transcriptional regulators such as Snail and ZEB2, and is sufficient to drive the transition to epithelial phenotypes. Differential Exo70 isoforms expression in human tumors correlates with cancer progression, and increased expression of the epithelial isoform of Exo70 inhibits tumor metastasis in mice. At the molecular level, the mesenchymal but not the epithelial isoform of Exo70 interacts with the Arp2/3 complex and stimulates actin polymerization for tumor invasion. Our findings provide a mechanism by which the exocyst function and actin dynamics are modulated for EMT and tumor invasion. PMID:24331928

  1. Effect of proteasome inhibitors on expression of HLA-G isoforms.

    Science.gov (United States)

    Poláková, K; Bandzuchová, E; Bystrická, M; Pancuchárová, H; Russ, G

    2006-01-01

    HLA-G primary transcript is alternatively spliced into a number of mRNAs. In addition to full length HLA-G1 protein isoform these mRNAs might also encode truncated HLA-G protein isoforms lacking one or two extracellular domains. Whereas HLA-G1 protein isoform is regularly identified, truncated HLAG protein isoforms are not detected even if all alternative spliced mRNAs are present in cells. The absence of entire domain(s) renders the truncated HLA-G protein isoforms incapable of binding peptide and beta2-microglobulin. These features of truncated HLA-G protein isoforms may result in their rapid degradation by proteasomes. Here we show that despite the presence of all alternatively spliced HLA-G transcripts in JEG-3 cells pretreated with proteasome inhibitors only a full length HLA-G1 protein isoform was regularly detected. Interestingly, immunoblot analysis showed slight increase of HLA-G1 protein in cells pretreated with proteasome inhibitors, although the expression of HLA-G1 transcript was basically not affected. Expression of HLA-G3 transcript increased in JEG-3 cells pre-incubated with LLL, however, neither HLA-G3 nor other HLA-G short protein isoform was regularly detected. In K562 transfectants proteasome inhibitor LLL greatly enhanced expression of the HLA-G1 and -G2 transcripts as well as corresponding protein isoforms. Flow cytometry analysis showed that in cells pre-treated with proteasome inhibitors cell surface expression of HLA-G1 protein decreased but the quantity of intracellularly localized HLA-G antigens increased. Altogether our results suggest that truncated HLA-G proteins isoforms are not detected in JEG-3 cells as a result of their instability and the low translation efficiency of truncated HLA-G transcripts.

  2. Characterization of ductal and lobular breast carcinomas using novel prolactin receptor isoform specific antibodies

    Directory of Open Access Journals (Sweden)

    Heger Christopher D

    2010-12-01

    Full Text Available Abstract Background Prolactin is a polypeptide hormone responsible for proliferation and differentiation of the mammary gland. More recently, prolactin's role in mammary carcinogenesis has been studied with greater interest. Studies from our laboratory and from others have demonstrated that three specific isoforms of the prolactin receptor (PRLR are expressed in both normal and cancerous breast cells and tissues. Until now, reliable isoform specific antibodies have been lacking. We have prepared and characterized polyclonal antibodies against each of the human PRLR isoforms that can effectively be used to characterize human breast cancers. Methods Rabbits were immunized with synthetic peptides of isoform unique regions and immune sera affinity purified prior to validation by Western blot and immunohistochemical analyses. Sections of ductal and lobular carcinomas were stained with each affinity purified isoform specific antibody to determine expression patterns in breast cancer subclasses. Results We show that the rabbit antibodies have high titer and could specifically recognize each isoform of PRLR. Differences in PRLR isoform expression levels were observed and quantified using histosections from xenografts of established human breast cancer cells lines, and ductal and lobular carcinoma human biopsy specimens. In addition, these results were verified by real-time PCR with isoform specific primers. While nearly all tumors contained LF and SF1b, the majority (76% of ductal carcinoma biopsies expressed SF1a while the majority of lobular carcinomas lacked SF1a staining (72% and 27% had only low levels of expression. Conclusions Differences in the receptor isoform expression profiles may be critical to understanding the role of PRL in mammary tumorigenesis. Since these antibodies are specifically directed against each PRLR isoform, they are valuable tools for the evaluation of breast cancer PRLR content and have potential clinical importance in

  3. Identification of a novel dioxygenase involved in metabolism of o-xylene, toluene, and ethylbenzene by Rhodococcus sp. strain DK17.

    Science.gov (United States)

    Kim, Dockyu; Chae, Jong-Chan; Zylstra, Gerben J; Kim, Young-Soo; Kim, Seong-Ki; Nam, Myung Hee; Kim, Young Min; Kim, Eungbin

    2004-12-01

    Rhodococcus sp. strain DK17 is able to grow on o-xylene, benzene, toluene, and ethylbenzene. DK17 harbors at least two megaplasmids, and the genes encoding the initial steps in alkylbenzene metabolism are present on the 330-kb pDK2. The genes encoding alkylbenzene degradation were cloned in a cosmid clone and sequenced completely to reveal 35 open reading frames (ORFs). Among the ORFs, we identified two nearly exact copies (one base difference) of genes encoding large and small subunits of an iron sulfur protein terminal oxygenase that are 6 kb apart from each other. Immediately downstream of one copy of the dioxygenase genes (akbA1a and akbA2a) is a gene encoding a dioxygenase ferredoxin component (akbA3), and downstream of the other copy (akbA1b and akbA2b) are genes putatively encoding a meta-cleavage pathway. RT-PCR experiments show that the two copies of the dioxygenase genes are operonic with the downstream putative catabolic genes and that both operons are induced by o-xylene. When expressed in Escherichia coli, AkbA1a-AkbA2a-AkbA3 transformed o-xylene into 2,3- and 3,4-dimethylphenol. These were apparently derived from an unstable o-xylene cis-3,4-dihydrodiol, which readily dehydrates. This indicates a single point of attack of the dioxygenase on the aromatic ring. In contrast, attack of AkbA1a-AkbA2a-AkbA3 on ethylbenzene resulted in the formation of two different cis-dihydrodiols resulting from an oxidation at the 2,3 and the 3,4 positions on the aromatic ring, respectively. PMID:15574904

  4. Interaction of Carthamus tinctorius lignan arctigenin with the binding site of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase

    OpenAIRE

    Temml, Veronika; Kuehnl, Susanne; Schuster, Daniela; Schwaiger, Stefan; Stuppner, Hermann; Fuchs, Dietmar

    2013-01-01

    Mediterranean Carthamus tinctorius (Safflower) is used for treatment of inflammatory conditions and neuropsychiatric disorders. Recently C. tinctorius lignans arctigenin and trachelogenin but not matairesinol were described to interfere with the activity of tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) in peripheral blood mononuclear cells in vitro. We examined a potential direct influence of compounds on IDO enzyme activity applying computational calculations based on 3D geom...

  5. Analysis of multi-domain hypothetical proteins containing iron-sulphur clusters and fad ligands reveal rieske dioxygenase activity suggesting their plausible roles in bioremediation.

    Science.gov (United States)

    Sathyanarayanan, Nitish; Nagendra, Holenarasipur Gundurao

    2012-01-01

    'Conserved hypothetical' proteins pose a challenge not just for functional genomics, but also to biology in general. As long as there are hundreds of conserved proteins with unknown function in model organisms such as Escherichia coli, Bacillus subtilis or Saccharomyces cerevisiae, any discussion towards a 'complete' understanding of these biological systems will remain a wishful thinking. Insilico approaches exhibit great promise towards attempts that enable appreciating the plausible roles of these hypothetical proteins. Among the majority of genomic proteins, two-thirds in unicellular organisms and more than 80% in metazoa, are multi-domain proteins, created as a result of gene duplication events. Aromatic ring-hydroxylating dioxygenases, also called Rieske dioxygenases (RDOs), are class of multi-domain proteins that catalyze the initial step in microbial aerobic degradation of many aromatic compounds. Investigations here address the computational characterization of hypothetical proteins containing Ferredoxin and Flavodoxin signatures. Consensus sequence of each class of oxidoreductase was obtained by a phylogenetic analysis, involving clustering methods based on evolutionary relationship. A synthetic sequence was developed by combining the consensus, which was used as the basis to search for their homologs via BLAST. The exercise yielded 129 multidomain hypothetical proteins containing both 2Fe-2S (Ferredoxin) and FNR (Flavodoxin) domains. In the current study, 40 proteins with N-terminus 2Fe-2S domain and C-terminus FNR domain are characterized, through homology modelling and docking exercises which suggest dioxygenase activity indicating their plausible roles in degradation of aromatic moieties.

  6. A murine model for type III tyrosinemia: lack of immunologically detectable 4-hydroxyphenylpyruvic acid dioxygenase enzyme protein in a novel mouse strain with hypertyrosinemia.

    Science.gov (United States)

    Endo, F; Katoh, H; Yamamoto, S; Matsuda, I

    1991-04-01

    We have characterized a new mutant strain of mouse that has hypertyrosinemia. The blood tyrosine level was persistently high, and increased amounts of 4-hydroxyphenylpyruvic acid and its derivatives were excreted into the urine. Succinylacetone was not detected in urine samples from these mice. All the animals were apparently healthy, and there was no evidence of hepatorenal dysfunction. The hypertyrosinemia was transmitted through an autosomal recessive inheritance. Analyses of hepatic enzymes related to tyrosine metabolism revealed that 4-hydroxyphenylpyruvic acid dioxygenase activity was virtually absent, while fumarylacetoacetase and tyrosine aminotransferases (cytosolic and mitochondrial forms) were normal in these mutant mice. Immunoblot analysis of 4-hydroxyphenylpyruvic acid dioxygenase protein in the liver indicated that the subunit protein of the enzyme was absent. It would appear that hypertyrosinemia in this mutant strain was caused by a genetic defect in 4-hydroxyphenylpyruvic acid dioxygenase. These features are similar to type III tyrosinemia in humans. Analysis of this mutant strain of mouse is expected to provide valuable information on the pathogenesis of human type III tyrosinemia and can also serve as a useful system for studies on tyrosine metabolism.

  7. The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis.

    Science.gov (United States)

    Krüßel, Lena; Junemann, Johannes; Wirtz, Markus; Birke, Hannah; Thornton, Jeremy D; Browning, Luke W; Poschet, Gernot; Hell, Rüdiger; Balk, Janneke; Braun, Hans-Peter; Hildebrandt, Tatjana M

    2014-05-01

    The sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) catalyzes the oxidation of persulfides in the mitochondrial matrix and is essential for early embryo development in Arabidopsis (Arabidopsis thaliana). We investigated the biochemical and physiological functions of ETHE1 in plant metabolism using recombinant Arabidopsis ETHE1 and three transfer DNA insertion lines with 50% to 99% decreased sulfur dioxygenase activity. Our results identified a new mitochondrial pathway catalyzing the detoxification of reduced sulfur species derived from cysteine catabolism by oxidation to thiosulfate. Knockdown of the sulfur dioxygenase impaired embryo development and produced phenotypes of starvation-induced chlorosis during short-day growth conditions and extended darkness, indicating that ETHE1 has a key function in situations of high protein turnover, such as seed production and the use of amino acids as alternative respiratory substrates during carbohydrate starvation. The amino acid profile of mutant plants was similar to that caused by defects in the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex and associated dehydrogenases. Thus, in addition to sulfur amino acid catabolism, ETHE1 also affects the oxidation of branched-chain amino acids and lysine.

  8. Androgen receptor isoforms in human prostatic cancer tissue and LNCaP cell line

    Institute of Scientific and Technical Information of China (English)

    Shu-Jie XIA; Xiao-Da TANG; Qing-Zheng MA

    2001-01-01

    Aim: To investigate the androgen receptor (AR) isoform expressions in human prostatic cancer tissue and LNCaP cell line. Methods: With high resolution isoelectric focusing (IEF) method we demonstrated the different expressions of AR isoforms in human prostatic cancer tissues and LNCaP cell line. Results: Data were obtained from three prostatic cancer specimens and the LNCaP cell line. Three types of AR isoforms were detected with pI values at 6.5,6.0, and 5.3. For the 3 prostatic cancer specimens, 1 sample showed all the three types of AR isoforms, the second specimen expressed at 6.5 and 6.0, and the third failed to show any type of isoforms. The LNCaP cell line expressed all the three AR isoforms. Binding of 3H-dihydrotestosterone (3H-DHT) to these three isoforms was inhibited by the addition ofl00-fold excess of DHT or testosterone, while not by progesterone, oestradiol and diethylstilboestrol. Conclusion: The expression of AR isofonns is different in different prostate cancer tissues, which may be related to the difference in the effect of anti-androgen therapy in different patients.

  9. VEGF-A isoforms program differential VEGFR2 signal transduction, trafficking and proteolysis

    Science.gov (United States)

    Fearnley, Gareth W.; Smith, Gina A.; Abdul-Zani, Izma; Yuldasheva, Nadira; Mughal, Nadeem A.; Homer-Vanniasinkam, Shervanthi; Kearney, Mark T.; Zachary, Ian C.; Tomlinson, Darren C.; Harrison, Michael A.; Wheatcroft, Stephen B.; Ponnambalam, Sreenivasan

    2016-01-01

    ABSTRACT Vascular endothelial growth factor A (VEGF-A) binding to the receptor tyrosine kinase VEGFR2 triggers multiple signal transduction pathways, which regulate endothelial cell responses that control vascular development. Multiple isoforms of VEGF-A can elicit differential signal transduction and endothelial responses. However, it is unclear how such cellular responses are controlled by isoform-specific VEGF-A–VEGFR2 complexes. Increasingly, there is the realization that the membrane trafficking of receptor–ligand complexes influences signal transduction and protein turnover. By building on these concepts, our study shows for the first time that three different VEGF-A isoforms (VEGF-A165, VEGF-A121 and VEGF-A145) promote distinct patterns of VEGFR2 endocytosis for delivery into early endosomes. This differential VEGFR2 endocytosis and trafficking is linked to VEGF-A isoform-specific signal transduction events. Disruption of clathrin-dependent endocytosis blocked VEGF-A isoform-specific VEGFR2 activation, signal transduction and caused substantial depletion in membrane-bound VEGFR1 and VEGFR2 levels. Furthermore, such VEGF-A isoforms promoted differential patterns of VEGFR2 ubiquitylation, proteolysis and terminal degradation. Our study now provides novel insights into how different VEGF-A isoforms can bind the same receptor tyrosine kinase and elicit diverse cellular outcomes. PMID:27044325

  10. VEGF-A isoforms program differential VEGFR2 signal transduction, trafficking and proteolysis

    Directory of Open Access Journals (Sweden)

    Gareth W. Fearnley

    2016-05-01

    Full Text Available Vascular endothelial growth factor A (VEGF-A binding to the receptor tyrosine kinase VEGFR2 triggers multiple signal transduction pathways, which regulate endothelial cell responses that control vascular development. Multiple isoforms of VEGF-A can elicit differential signal transduction and endothelial responses. However, it is unclear how such cellular responses are controlled by isoform-specific VEGF-A–VEGFR2 complexes. Increasingly, there is the realization that the membrane trafficking of receptor–ligand complexes influences signal transduction and protein turnover. By building on these concepts, our study shows for the first time that three different VEGF-A isoforms (VEGF-A165, VEGF-A121 and VEGF-A145 promote distinct patterns of VEGFR2 endocytosis for delivery into early endosomes. This differential VEGFR2 endocytosis and trafficking is linked to VEGF-A isoform-specific signal transduction events. Disruption of clathrin-dependent endocytosis blocked VEGF-A isoform-specific VEGFR2 activation, signal transduction and caused substantial depletion in membrane-bound VEGFR1 and VEGFR2 levels. Furthermore, such VEGF-A isoforms promoted differential patterns of VEGFR2 ubiquitylation, proteolysis and terminal degradation. Our study now provides novel insights into how different VEGF-A isoforms can bind the same receptor tyrosine kinase and elicit diverse cellular outcomes.

  11. Estrogen and progesterone receptor isoforms expression in the stomach of Mongolian gerbils

    Institute of Scientific and Technical Information of China (English)

    Milena Saqui-Salces; Teresa Neri-Gómez; Armando Gamboa-Dominguez; Guillermo Ruiz-Palacios; Ignacio Camacho-Arroyo

    2008-01-01

    AIM:We studied the estrogen receptor (ER) and progesterone receptor (PR) isoforms expression in gastric antrum and corpus of female gerbils and their regulation by estradiol (E2) and progesterone (P4).METHODS: Ovariectomized adult female gerbils were subcutaneously treated with E2,and E2 + P4.Uteri and stomachs were removed,the latter were cut along the greater curvature,and antrum and corpus were excised.Proteins were immunoblotted using antibodies that recognize ER-alpha,ER-beta,and PR-A and PR-B receptor isoforms.Tissues from rats treated in the same way were used as controls.RESULTS: Specific bands were detected for ER-alpha (68 KDa),and PR isoforms (85 and 120 KDa for PR-A and PR-B isoforrns,respectively) in uteri,gastric antrum and corpus.We could not detect ER-beta isoform.PR isoforms were not regulated by E2 or P4 in uterus and gastric tissues of gerbils.ER-alpha isoform content was significantly down-regulated by E2 in the corpus,but not affected by hormones in uterus and gastric antrum.CONCLUSION: The presence of ER-alpha and PR isoforms in gerbils stomach suggests that E2 and P4 actions in this organ are in part mediated by their nuclear receptors.

  12. Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL isoforms.

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    Christian Krintel

    Full Text Available BACKGROUND: Hormone-sensitive lipase (HSL is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa expressed in a tissue-dependent manner, where the predominant 84 kDa form in adipocytes is the most extensively studied. METHODOLOGY/PRINCIPAL FINDINGS: In this study we employed negative stain electron microscopy (EM to analyze the quarternary structure of the different HSL isoforms. The results show that all three isoforms adopt a head-to-head homodimeric organization, where each monomer contains two structural domains. We also used enzymatic assays to show that despite the variation in the size of the N-terminal domain all three isoforms exhibit similar enzymological properties with regard to psychrotolerance and protein kinase A (PKA-mediated phosphorylation and activation. CONCLUSIONS/SIGNIFICANCE: We present the first data on the quaternary structure and domain organization of the three HSL isoforms. We conclude that despite large differences in the size of the N-terminal, non-catalytic domain all three HSL isoforms exhibit the same three-dimensional architecture. Furthermore, the three HSL isoforms are very similar with regard to two unique enzymological characteristics of HSL, i.e., cold adaptation and PKA-mediated activation.

  13. Dynamic expression and localization of c-MET isoforms in the developing rat pancreas.

    Science.gov (United States)

    Wu, Yulong; Cheng, Mei; Shi, Zhen; Feng, Zhenqing; Guan, Xiaohong

    2014-01-01

    Pancreata from Sprague Dawley rats of different developmental stages were studied to determine the expression and cellular localization of different c-MET isoforms in the developing rat pancreas. Pancreatic mRNA and protein expression levels of c-MET at different developmental stages from embryo to adult were detected by reverse transcription-polymerase chain reaction and by western blotting. To identify the cellular localization of c-MET protein in the developing rat pancreas, double immunofluorescent staining was performed using antibodies for cell type-specific markers and for c-MET. The expression of two isoforms of c-MET (190 kDa and 170 kDa) coincided with the development of the pancreas. The 190 kDa isoform of c-MET is expressed during embryonic stages, and its expression is replaced by the expression of the 170 kDa isoform as the pancreas develops. Only the 170 kDa isoform is expressed in the adult rat pancreas. Throughout all stages of pancreatic development, c-MET is expressed by vimentin-positive cells. In contrast, c-MET staining was stronger in rat pancreata from newborn to adult stages and overlapped with insulin-positive beta-cells. The dynamic expression and localization of different c-MET isoforms in the rat pancreas during different developmental stages indicates that distinct c-MET isoform might be involved in different aspects of pancreatic development.

  14. Inulin isoforms differ by repeated additions of one crystal unit cell.

    Science.gov (United States)

    Cooper, Peter D; Barclay, Thomas G; Ginic-Markovic, Milena; Gerson, Andrea R; Petrovsky, Nikolai

    2014-03-15

    Inulin isoforms, especially delta inulin, are important biologically as immune activators and clinically as vaccine adjuvants. In exploring action mechanisms, we previously found regular increments in thermal properties of the seven-member inulin isoform series that suggested regular additions of some energetic structural unit. Because the previous isolates carried additional longer chains that masked defining ranges, these were contrasted with new isoform isolates comprising only inulin chain lengths defining that isoform. The new series began with 19 fructose units per chain (alpha-1 inulin), increasing regularly by 6 fructose units per isoform. Thus the 'energetic unit' equates to 6 fructose residues per chain. All isoforms showed indistinguishable X-ray diffraction patterns that were also identical with known inulin crystals. We conclude that an 'energetic unit' equates to one helix turn of 6 fructose units per chain as found in one unit cell of the inulin crystal. Each isoform chain comprised progressively more helix turns plus one additional fructose and glucose residues per chain.

  15. The isolation of parvalbumin isoforms from the tail muscle of the American alligator (Alligator mississipiensis).

    Science.gov (United States)

    Laney, E L; Shabanowitz, J; King, G; Hunt, D F; Nelson, D J

    1997-04-01

    Multiple parvalbumin isoforms have been detected in the tail (skeletal) muscle of the American alligator (Alligator mississipiensis). One of these isoforms (APV-1) has been highly purified and partially characterized. Protein purification involved mainly gel filtration and anion exchange chromatography, and characterization included gel electrophoresis, amino acid composition analysis, metal ion analysis, MALDI-TOF and ESI mass spectrometry, ultraviolet and fluorescence spectroscopy, and one- and two-dimensional 500 MHz proton NMR spectroscopy. The alligator isoforms are rich in phenylalanine and deficient in the other aromatic residues as is typical for parvalbumins. In fact, the one highly purified isoform that forms the basis of this study has only phenyl-alanine as an aromatic residue. Ion exchange chromatography further indicates that this isoform has a relatively high isoelectric point (pl approximately 5.0), indicating that it is an alpha-lineage parvalbumin. This alligator parvalbumin isoform is unusual in that it has an atypically high Ca2+ content (almost 3.0 mole of Ca2+ per mole of protein) following purification, a fact supported by terbium fluorescence titration experiments. Preliminary comparative analysis of the highly purified alligator parvalbumin isoform (in the Ca2-loaded state) by two-dimensional 1H-NMR (2D 1H TOCSY and 2D 1H NOESY) indicates that there is considerable similarity in structure between the alligator protein and a homologous protein obtained from the silver hake (a saltwater fish species). PMID:9076974

  16. Learning-dependent gene expression of CREB1 isoforms in the molluscan brain

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    Hisayo Sadamoto

    2010-05-01

    Full Text Available Cyclic AMP-responsive element binding protein1 (CREB1 has multiple functions in gene regulation. Various studies have reported that CREB1-dependent gene induction is necessary for memory formation and long-lasting behavioral changes in both vertebrates and invertebrates. In the present study, we characterized Lymnaea CREB1 (LymCREB1 mRNA isoforms of spliced variants in the central nervous system (CNS of the pond snail Lymnaea stagnalis. Among these spliced variants, the three isoforms that code a whole LymCREB1 protein are considered to be the activators for gene regulation. The other four isoforms, which code truncated LymCREB1 proteins with no kinase inducible domain, are the repressors. For a better understanding of the possible roles of different LymCREB1 isoforms, the expression level of these isoform mRNAs was investigated by a real-time quantitative RT-PCR method. Further, we examined the changes in gene expression for all the isoforms in the CNS after conditioned taste aversion (CTA learning or backward conditioning as a control. The results showed that CTA learning increased LymCREB1 gene expression, but it did not change the activator/repressor ratio. Our findings showed that the repressor isoforms, as well as the activator ones, are expressed in large amounts in the CNS, and the gene expression of CREB1 isoforms appeared to be specific for the given stimulus. This was the first quantitative analysis of the expression patterns of CREB1 isoforms at the mRNA level and their association with learning behavior.

  17. The polysaccharide inulin is characterized by an extensive series of periodic isoforms with varying biological actions.

    Science.gov (United States)

    Cooper, Peter D; Barclay, Thomas G; Ginic-Markovic, Milena; Petrovsky, Nikolai

    2013-10-01

    In studying the molecular basis for the potent immune activity of previously described gamma and delta inulin particles and to assist in production of inulin adjuvants under Good Manufacturing Practice, we identified five new inulin isoforms, bringing the total to seven plus the amorphous form. These isoforms comprise the step-wise inulin developmental series amorphous → alpha-1 (AI-1) → alpha-2 (AI-2) → gamma (GI) → delta (DI) → zeta (ZI) → epsilon (EI) → omega (OI) in which each higher isoform can be made either by precipitating dissolved inulin or by direct conversion from its precursor, both cases using regularly increasing temperatures. At higher temperatures, the shorter inulin polymer chains are released from the particle and so the key difference between isoforms is that each higher isoform comprises longer polymer chains than its precursor. An increasing trend of degree of polymerization is confirmed by end-group analysis using (1)H nuclear magnetic resonance spectroscopy. Inulin isoforms were characterized by the critical temperatures of abrupt phase-shifts (solubilizations or precipitations) in water suspensions. Such (aqueous) "melting" or "freezing" points are diagnostic and occur in strikingly periodic steps reflecting quantal increases in noncovalent bonding strength and increments in average polymer lengths. The (dry) melting points as measured by modulated differential scanning calorimetry similarly increase in regular steps. We conclude that the isoforms differ in repeated increments of a precisely repeating structural element. Each isoform has a different spectrum of biological activities and we show the higher inulin isoforms to be more potent alternative complement pathway activators.

  18. Myosin isoform fiber type and fiber size in the tail of the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Hazimihalis, P J; Gorvet, M A; Butcher, M T

    2013-01-01

    Muscle fiber type is a well studied property in limb muscles, however, much less is understood about myosin heavy chain (MHC) isoform expression in caudal muscles of mammalian tails. Didelphid marsupials are an interesting lineage in this context as all species have prehensile tails, but show a range of tail-function depending on either their arboreal or terrestrial locomotor habits. Differences in prehensility suggest that MHC isoform fiber types may also be different, in that terrestrial opossums may have a large distribution of oxidative fibers for object carrying tasks instead of faster, glycolytic fiber types expected in mammals with long tails. To test this hypothesis, MHC isoform fiber type and their regional distribution (proximal/transitional/distal) were determined in the tail of the Virginia opossum (Didelphis virginiana). Fiber types were determined by a combination of myosin-ATPase histochemistry, immunohistochemistry, and SDS-PAGE. Results indicate a predominance of the fast MHC-2A and -2X isoforms in each region of the tail. The presence of two fast isoforms, in addition to the slow MHC-1 isoform, was confirmed by SDS-PAGE analysis. The overall MHC isoform fiber type distribution for the tail was: 25% MHC-1, 71% MHC-2A/X hybrid, and 4% MHC-1/2A hybrid. Oxidative MHC-2A/X isoform fibers were found to be relatively large in cross-section compared to slow, oxidative MHC-1 and MHC-1/2A hybrid fibers. A large percentage of fast MHC-2A/X hybrids fibers may be suggestive of an evolutionary transition in MHC isoform distribution (fast-to-slow fiber type) in the tail musculature of an opossum with primarily a terrestrial locomotor habit and adaptive tail-function. PMID:23152195

  19. Isoform-specific upregulation of palladin in human and murine pancreas tumors.

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    Silvia M Goicoechea

    Full Text Available Pancreatic ductal adenocarcinoma (PDA is a lethal disease with a characteristic pattern of early metastasis, which is driving a search for biomarkers that can be used to detect the cancer at an early stage. Recently, the actin-associated protein palladin was identified as a candidate biomarker when it was shown that palladin is mutated in a rare inherited form of PDA, and overexpressed in many sporadic pancreas tumors and premalignant precursors. In this study, we analyzed the expression of palladin isoforms in murine and human PDA and explored palladin's potential use in diagnosing PDA. We performed immunohistochemistry and immunoblot analyses on patient samples and tumor-derived cells using an isoform-selective monoclonal antibody and a pan-palladin polyclonal antibody. Immunoblot and real-time quantitative reverse transcription-PCR were used to quantify palladin mRNA levels in human samples. We show that there are two major palladin isoforms expressed in pancreas: 65 and 85-90 kDa. The 65 kDa isoform is expressed in both normal and neoplastic ductal epithelial cells. The 85-90 kDa palladin isoform is highly overexpressed in tumor-associated fibroblasts (TAFs in both primary and metastatic tumors compared to normal pancreas, in samples obtained from either human patients or genetically engineered mice. In tumor-derived cultured cells, expression of palladin isoforms follows cell-type specific patterns, with the 85-90 kDa isoform in TAFs, and the 65 kDa isoform predominating in normal and neoplastic epithelial cells. These results suggest that upregulation of 85-90 kDa palladin isoform may play a role in the establishment of the TAF phenotype, and thus in the formation of a desmoplastic tumor microenvironment. Thus, palladin may have a potential use in the early diagnosis of PDA and may have much broader significance in understanding metastatic behavior.

  20. Detection of VEGF-A(xxx)b isoforms in human tissues.

    Science.gov (United States)

    Bates, David O; Mavrou, Athina; Qiu, Yan; Carter, James G; Hamdollah-Zadeh, Maryam; Barratt, Shaney; Gammons, Melissa V; Millar, Ann B; Salmon, Andrew H J; Oltean, Sebastian; Harper, Steven J

    2013-01-01

    Vascular Endothelial Growth Factor-A (VEGF-A) can be generated as multiple isoforms by alternative splicing. Two families of isoforms have been described in humans, pro-angiogenic isoforms typified by VEGF-A165a, and anti-angiogenic isoforms typified by VEGF-A165b. The practical determination of expression levels of alternative isoforms of the same gene may be complicated by experimental protocols that favour one isoform over another, and the use of specific positive and negative controls is essential for the interpretation of findings on expression of the isoforms. Here we address some of the difficulties in experimental design when investigating alternative splicing of VEGF isoforms, and discuss the use of appropriate control paradigms. We demonstrate why use of specific control experiments can prevent assumptions that VEGF-A165b is not present, when in fact it is. We reiterate, and confirm previously published experimental design protocols that demonstrate the importance of using positive controls. These include using known target sequences to show that the experimental conditions are suitable for PCR amplification of VEGF-A165b mRNA for both q-PCR and RT-PCR and to ensure that mispriming does not occur. We also provide evidence that demonstrates that detection of VEGF-A165b protein in mice needs to be tightly controlled to prevent detection of mouse IgG by a secondary antibody. We also show that human VEGF165b protein can be immunoprecipitated from cultured human cells and that immunoprecipitating VEGF-A results in protein that is detected by VEGF-A165b antibody. These findings support the conclusion that more information on the biology of VEGF-A165b isoforms is required, and confirm the importance of the experimental design in such investigations, including the use of specific positive and negative controls.

  1. Expression, Function of the Human Androgen-Responsive Gene AD11 in Prostate Cancer

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    Shane W. Oram

    2007-08-01

    Full Text Available We have previously identified an androgen-responsive gene in rat prostate that shares homology with the acireductone dioxygenase (ARD/ARD′ family of metalbinding enzymes involved in methionine salvage. We found that the gene, aci-reductone dioxygenase 1 (ADI1, was downregulated in prostate cancer cells, whereas enforced expression of rat Adi1 in these cells caused apoptosis. Here we report the characterization of human ADI1 in prostate cancer. Androgens induced ADI1 expression in human prostate cancer LNCaP cells, which was not blocked by cycloheximide, indicating that ADI1 is a primary androgen-responsive gene. In human benign prostatic hyperplasia specimens, epithelial cells expressed ADI1. Immunohistochemistry of prostate tumor tissue microarrays showed that benign regions expressed more ADI1 than tumors, suggesting a suppressive role for ADI1 in prostate cancer. Bacterial lysates containing recombinant ADI1 produced a five-fold increase in aci-reductone decay over controls, demonstrating that ADI1 has ARD activity. We generated point mutations at key residues in the metal-binding site of ADI1 to disrupt ARD function, we found that these mutations did not affect intracellular localization, apoptosis, or colony formation suppression in human prostate cancer cells. Collectively, these observations argue that AD11 may check prostate cancer progression through apoptosis, that this activity does not require metal binding.

  2. Purification and Characterization of Two Voltage-Dependent Anion Channel Isoforms from Plant Seeds1

    Science.gov (United States)

    Abrecht, Helge; Wattiez, Ruddy; Ruysschaert, Jean-Marie; Homblé, Fabrice

    2000-01-01

    Mitochondria were isolated from imbibed seeds of lentil (Lens culinaris) and Phaseolus vulgaris. We copurified two voltage-dependent anion channel from detergent solubilized mitochondria in a single purification step using hydroxyapatite. The two isoforms from P. vulgaris were separated by chromatofocusing chromatography in 4 m urea without any loss of channel activity. Channel activity of each isoform was characterized upon reconstitution into diphytanoyl phosphatidylcholine planar lipid bilayers. Both isoforms form large conductance channels that are slightly anion selective and display cation selective substates. PMID:11080295

  3. Purification and characterization of two voltage-dependent anion channel isoforms from plant seeds.

    Science.gov (United States)

    Abrecht, H; Wattiez, R; Ruysschaert, J M; Homblé, F

    2000-11-01

    Mitochondria were isolated from imbibed seeds of lentil (Lens culinaris) and Phaseolus vulgaris. We copurified two voltage-dependent anion channel from detergent solubilized mitochondria in a single purification step using hydroxyapatite. The two isoforms from P. vulgaris were separated by chromatofocusing chromatography in 4 M urea without any loss of channel activity. Channel activity of each isoform was characterized upon reconstitution into diphytanoyl phosphatidylcholine planar lipid bilayers. Both isoforms form large conductance channels that are slightly anion selective and display cation selective substates.

  4. Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases.

    Science.gov (United States)

    Kundu, Siddhartha

    2015-01-01

    Could a disjoint group of enzymes synchronize their activities and execute a complex multi-step, measurable, and reproducible response? Here, I surmise that the alpha-ketoglutarate dependent superfamily of non-haem iron (II) dioxygenases could influence cell physiology as a cohesive unit, and that the broad spectra of substrates transformed is an absolute necessity to this portrayal. This eclectic group comprises members from all major taxa, and participates in pesticide breakdown, hypoxia signaling, and osmotic stress neutralization. The oxidative decarboxylation of 2-oxoglutarate to succinate is coupled with a concomitant substrate hydroxylation and, in most cases, is followed by an additional specialized conversion. The domain profile of a protein sequence was used as an index of miscellaneous reaction chemistry and interpreted alongside existent kinetic data in a linear model of integrated function. Statistical parameters were inferred by the creation of a novel, empirically motivated flat-file database of over 3800 sequences (DB2OG) with putative 2-oxoglutarate dependent activity. The collated information was categorized on the basis of existing annotation schema. The data suggests that 2OG-dependent enzymes incorporate several desirable features of a systems level player. DB2OG, is free, accessible without a login to all users, and available at the following URL (http://comp-biol.theacms.in/DB2OG.html).

  5. Structure prediction of Fe(II) 2-oxoglutarate dioxygenase from a psychrophilic yeast Glaciozyma antarctica PI12

    Science.gov (United States)

    Yusof, Nik Yusnoraini; Bakar, Farah Diba Abu; Mahadi, Nor Muhammad; Raih, Mohd Firdaus; Murad, Abdul Munir Abdul

    2015-09-01

    A cDNA encoding Fe(II) 2-oxoglutarate (2OG) dependent dioxygenases was isolated from psychrophilic yeast, Glaciozyma antarctica PI12. We have successfully amplified 1,029 bp cDNA sequence that encodes 342 amino acid with predicted molecular weight 38 kDa. The prediction protein was analysed using various bioinformatics tools to explore the properties of the protein. Based on a BLAST search analysis, the Fe2OX amino acid sequence showed 61% identity to the sequence of oxoglutarate/iron-dependent oxygenase from Rhodosporidium toruloides NP11. SignalP prediction showed that the Fe2OX protein contains no putative signal peptide, which suggests that this enzyme most probably localised intracellularly.The structure of Fe2OX was predicted by homology modelling using MODELLER9v11. The model with the lowest objective function was selected from hundred models generated using MODELLER9v11. Analysis of the structure revealed the longer loop at Fe2OX from G.antarctica that might be responsible for the flexibility of the structure, which contributes to its adaptation to low temperatures. Fe2OX hold a highly conserved Fe(II) binding HXD/E…H triad motif. The binding site for 2-oxoglutarate was found conserved for Arg280 among reported studies, however the Phe268 was found to be different in Fe2OX.

  6. Ring-hydroxylating dioxygenase (RHD) expression in a microbial community during the early response to oil pollution.

    Science.gov (United States)

    Paissé, Sandrine; Goñi-Urriza, Marisol; Stalder, Thibault; Stadler, Thibault; Budzinski, Hélène; Duran, Robert

    2012-04-01

    The early functional response of a bacterial community from the sediments of a chronically oil-polluted retention basin located at the Etang de Berre (France) was investigated just after petroleum addition. After removing hydrocarbon compounds by natural abiotic and biotic processes, the sediments were maintained in microcosms and Vic Bilh petroleum was added. The diversity and the expression of genes encoding ring-hydroxylating dioxygenases (RHD) were examined just after the petroleum addition until 14 days focussing on the first hours following the contamination. RHD gene copy numbers and diversity were maintained throughout all the incubation period; however, transcripts were detected only during the first 2 days. One dominant RHD gene, immediately and specifically expressed in response to petroleum contamination, was related to RHD gene carried by a plasmid found in Pseudomonas spp. The expression of the RHD genes was correlated with high biodegradation levels observed for low molecular weight PAHs at 7 days of incubation. The study shows that the bacterial metabolism induced just after the oil input is a key stage that could determine the bacterial community structure changes. Monitoring the expression of RHD genes, key genes involved in hydrocarbon degradation, may provide useful information for managing bioremediation processes.

  7. The carotenoid cleavage dioxygenase CCD2 catalysing the synthesis of crocetin in spring crocuses and saffron is a plastidial enzyme.

    Science.gov (United States)

    Ahrazem, Oussama; Rubio-Moraga, Angela; Berman, Judit; Capell, Teresa; Christou, Paul; Zhu, Changfu; Gómez-Gómez, Lourdes

    2016-01-01

    The apocarotenoid crocetin and its glycosylated derivatives, crocins, confer the red colour to saffron. Crocetin biosynthesis in saffron is catalysed by the carotenoid cleavage dioxygenase CCD2 (AIG94929). No homologues have been identified in other plant species due to the very limited presence of crocetin and its derivatives in the plant kingdom. Spring Crocus species with yellow flowers accumulate crocins in the stigma and tepals. Four carotenoid CCDs, namely CaCCD1, CaCCD2 and CaCCD4a/b and CaCCD4c were first cloned and characterized. CaCCD2 was localized in plastids, and a longer CCD2 version, CsCCD2L, was also localized in this compartment. The activity of CaCCD2 was assessed in Escherichia coli and in a stable rice gene function characterization system, demonstrating the production of crocetin in both systems. The expression of all isolated CCDs was evaluated in stigma and tepals at three key developmental stages in relation with apocarotenoid accumulation. CaCCD2 expression parallels crocin accumulation, but C14 apocarotenoids most likely are associated to the CaCCD1 activity in Crocus ancyrensis flowers. The specific CCD2 localization and its membrane interaction will contribute to the development of a better understanding of the mechanism of crocetin biosynthesis and regulation in the chromoplast. PMID:26377696

  8. 4-hydroxyphenylpyruvate dioxygenase catalysis: identification of catalytic residues and production of a hydroxylated intermediate shared with a structurally unrelated enzyme.

    Science.gov (United States)

    Raspail, Corinne; Graindorge, Matthieu; Moreau, Yohann; Crouzy, Serge; Lefèbvre, Bertrand; Robin, Adeline Y; Dumas, Renaud; Matringe, Michel

    2011-07-22

    4-Hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the conversion of 4-hydroxyphenylpyruvate (HPP) into homogentisate. HPPD is the molecular target of very effective synthetic herbicides. HPPD inhibitors may also be useful in treating life-threatening tyrosinemia type I and are currently in trials for treatment of Parkinson disease. The reaction mechanism of this key enzyme in both plants and animals has not yet been fully elucidated. In this study, using site-directed mutagenesis supported by quantum mechanical/molecular mechanical theoretical calculations, we investigated the role of catalytic residues potentially interacting with the substrate/intermediates. These results highlight the following: (i) the central role of Gln-272, Gln-286, and Gln-358 in HPP binding and the first nucleophilic attack; (ii) the important movement of the aromatic ring of HPP during the reaction, and (iii) the key role played by Asn-261 and Ser-246 in C1 hydroxylation and the final ortho-rearrangement steps (numbering according to the Arabidopsis HPPD crystal structure 1SQD). Furthermore, this study reveals that the last step of the catalytic reaction, the 1,2 shift of the acetate side chain, which was believed to be unique to the HPPD activity, is also catalyzed by a structurally unrelated enzyme.

  9. Reaction mechanism of homoprotocatechuate 2,3-dioxygenase with 4-nitrocatechol: implications for the role of substrate.

    Science.gov (United States)

    Dong, Geng; Lai, Wenzhen

    2014-02-20

    The reaction mechanism of the dioxygen activation by homoprotocatechuate 2,3-dioxygenase (HPCD) with the substrate 4-nitrocatechol was investigated by quantum mechanical/molecular mechanical calculations. Our results demonstrated that the experimentally determined side-on iron-oxygen complex in crystallo is a semiquinone substrate radical (SQ(•))-Fe(III)-hydroperoxo species, which could not act as the reactive species. In fact, the Fe(III)-superoxo species with a hydrogen bond between His200 and the proximal oxygen is the reactive oxygen species. The second-sphere His200 residue was found to play an important role in manipulating the orientation of the superoxide in the Fe-O2 adduct for the further reaction. The rate-limiting step is the attack of the superoxo group on the substrate with a barrier of 17.2 kcal/mol, in good agreement with the experimental value of 16.8 kcal/mol. The reaction mechanism was then compared with the one for HPCD with its native substrate homoprotocatechuate studied recently by the same methods, in which a hybrid SQ(•)-Fe(II)-O2(•-)/Fe(III)-O2(•-) was suggested to be the reactive species. Therefore, our studies suggested that the substrate plays important roles in the dioxygen activation by HPCD.

  10. Molecular cloning of hyoscyamine 6 beta-hydroxylase, a 2-oxoglutarate-dependent dioxygenase, from cultured roots of Hyoscyamus niger.

    Science.gov (United States)

    Matsuda, J; Okabe, S; Hashimoto, T; Yamada, Y

    1991-05-25

    Roots of several solanaceous plants produce anticholinergic alkaloids, hyoscyamine and scopolamine. Hyoscyamine 6 beta-hydroxylase, a 2-oxoglutarate-dependent dioxygenase (EC 1.14.11.11), catalyzes hydroxylation of hyoscyamine in the biosynthetic pathway leading to scopolamine. We report here on the isolation of cDNA clones encoding the hydroxylase from a cDNA library made from mRNA of the cultured roots of Hyoscyamus niger. The library was screened with three synthetic oligonucleotides that encode amino acid sequences of internal peptide fragments of the purified hydroxylase. Nucleotide sequence analysis of the cloned cDNA revealed an open reading frame that encodes 344 amino acids (Mr = 38,999). All 12 internal peptide fragments determined in the purified enzyme were found in the amino acid sequence deduced from the cDNA. With computer-aided comparison to other proteins we found that the hydroxylase is homologous to two synthases involved in the biosynthesis of beta-lactam antibiotics in some microorganisms and the gene products of tomato pTOM13 cDNA and maize A2 locus which had been proposed to catalyze oxidative reactions in the biosynthesis of ethylene and anthocyan, respectively. RNA blotting hybridization showed that mRNA of the hydroxylase is abundant in cultured roots and present in plant roots, but absent in leaves, stems, and cultured cells of H. niger. PMID:2033047

  11. Immunological and Nonimmunological Effects of Indoleamine 2,3-Dioxygenase on Breast Tumor Growth and Spontaneous Metastasis Formation

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    Vera Levina

    2012-01-01

    Full Text Available The role of the tryptophan-catabolizing enzyme, indoleamine 2,3-dioxygenase (IDO1, in tumor escape and metastasis formation was analyzed using two pairs of Ido1+ and Ido1− murine breast cancer cell lines. Ido1 expression in 4T1 cells was knocked down by shRNA, and Ido1 expression in NT-5 cells was upregulated by stable transfection. Growth of Ido1− tumors and spontaneous metastasis formation were inhibited in immunocompetent mice. A higher level of cytotoxic T lymphocytes was generated by spleen cells from mice bearing Ido1− tumors than Ido1+ tumors. Tumor and metastatic growth was enhanced in immunodeficient mice, confirming an intensified immune response in the absence of Ido1 expression. However, Ido1+ tumors grow faster than Ido1− tumors in immunodeficient SCID/beige mice (lacking T, B, and NK cells suggesting that some Ido1-controlled nonimmunological mechanisms may be involved in tumor cell growth regulation. In vitro experiments demonstrated that downregulation of Ido1 in tumor cells was associated with decreased cell proliferation, increased apoptosis, and changed expression of cell cycle regulatory genes, whereas upregulation of Ido1 in the cells had the opposite effects. Taken together, our findings indicate that Ido1 expression could exert immunological and nonimmunological effects in murine breast tumor cells.

  12. Scavenging properties of neutrophil 4-hydroxyphenylpyruvate dioxygenase are based on a hypothesis that does not stand up to scrutiny.

    Science.gov (United States)

    Salerno, Costantino; Zicari, Alessandra; Mari, Emanuela; D'Eufemia, Patrizia

    2014-10-01

    It was previously reported by D'Eufemia et al. [9] that neutrophil preparations from a patient with tyrosinemia type III, i.e. with inherited deficiency of 4-hydroxyphenylpyruvate dioxygenase (HPPD), exhibited a far higher NO release than controls, when NO was estimated in terms of nitrite content in the suspending media. It was hypothesized that HPPD might participate to NO sequestration in neutrophils and that excessive NO release might reflect the lack of the scavenging action in defective cells. In recent control experiments, we found that HPPD activity in neutrophils preparations from healthy subjects is below the detection limit of the enzymatic assay (less than 3nmol product/h per mg protein). This indicates that HPPD concentration in neutrophils is very low, if any, confirming what was already suggested in literature, and rules out the possibility of a prominent role of HPPD as NO scavenger in these cells. Moreover, we found that 500μM l-tyrosine increases nitrite release and accumulation in suspending media of U-937 cells, a human monoblast-like lymphoma cell line which displays many characteristics of macrophages, including the expression of inducible and endothelial nitric oxide synthases. We hypothesize that the increase of nitrite release by patient's neutrophils might be related to the presence of high l-tyrosine concentrations in the blood samples (426μmol/L instead of 52.1±10.9μmol/L as healthy subjects), rather than to HPPD deficiency of in these cells.

  13. Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases

    Directory of Open Access Journals (Sweden)

    Siddhartha eKundu

    2015-03-01

    Full Text Available Could a disjoint group of enzymes synchronize their activities and execute a complex multi-step, measurable, and reproducible response ? Here, I surmise that the alpha-ketoglutarate dependent superfamily of non-haem iron (II dioxygenases could influence cell physiology as a cohesive unit, and that the broad spectra of substrates transformed is an absolute necessity to this portrayal.This eclectic group comprises members from all major taxa, and participates in pesticide breakdown, hypoxia signaling, and osmotic stress neutralization. The oxidative decarboxylation of 2-oxoglutarate to succinate is coupled with a concomitant substrate hydroxylation and, in most cases, is followed by an additional specialized conversion. The domain profile of a protein sequence was used as an index of miscellaneous reaction chemistry and combined with available kinetic data to form a linear model of integrated function. Statistical parameters were inferred by the creation of a novel, empirically motivated flat-file database of over 3800 sequences (DB2OG with putative 2-oxoglutarate dependent activity. The collated information was categorized on the basis of existing annotation schema. The data suggests that the 2OG-dependent superfamily incorporates several desirable features of a systems level player. DB2OG, is free, accessible without a login to all users, and available at the following URL (http://comp-biol.theacms.in/DB2OG.html.

  14. Docking studies of antidepressants against single crystal structure of tryptophan 2, 3-dioxygenase using Molegro Virtual Docker software.

    Science.gov (United States)

    Dawood, Shazia; Zarina, Shamshad; Bano, Samina

    2014-09-01

    Tryptophan 2, 3-dioxygenase (TDO) a heme containing enzyme found in mammalian liver is responsible for tryptophan (Trp) catabolism. Trp is an essential amino acid that is degraded in to N-formylkynurenine by the action of TDO. The protein ligand interaction plays a significant role in structural based drug designing. The current study illustrates the binding of established antidepressants (ADs) against TDO enzyme using in-silico docking studies. For this purpose, Fluoxetine, Paroxetine, Sertraline, Fluvoxamine, Seproxetine, Citalopram, Moclobamide, Hyperforin and Amoxepine were selected. In-silico docking studies were carried out using Molegro Virtual Docker (MVD) software. Docking results show that all ADs fit well in the active site of TDO moreover Hyperforin and Paroxetine exhibited high docking scores of -152.484k cal/mol and -139.706k cal/mol, respectively. It is concluded that Hyperforin and Paroxetine are possible lead molecules because of their high docking scores as compared to other ADs examined. Therefore, these two ADs stand as potent inhibitors of TDO enzyme. PMID:25176248

  15. The nonoxidative conversion of nitroethane to ethylnitronate in Neurospora crassa 2-nitropropane dioxygenase is catalyzed by histidine 196.

    Science.gov (United States)

    Francis, Kevin; Gadda, Giovanni

    2008-09-01

    The deprotonation of nitroethane catalyzed by Neurospora crassa 2-nitropropane dioxygenase was investigated by measuring the formation and release of ethylnitronate formed in turnover as a function of pH and through mutagenesis studies. Progress curves for the enzymatic reaction obtained by following the increase in absorbance at 228 nm over time were visibly nonlinear, requiring a logarithmic approximation of the initial reaction rates for the determination of the kinetic parameters of the enzyme. The pH dependence of the second-order rate constant k cat/ K m with nitroethane as substrate implicates the presence of a group with a p K a of 8.1 +/- 0.1 that must be unprotonated for nitronate formation. Mutagenesis studies suggest that this group is histidine 196 as evident from the inability of a H196N variant form of the enzyme to catalyze the formation of ethylnitronate from nitroethane. Replacement of histidine 196 with asparagine resulted in an approximately 15-fold increase in the k cat/ K m with ethylnitronate as compared to the wild-type, which results from the inability of the mutant enzyme to undergo nonoxidative turnover. The results presented herein are consistent with a branched catalytic mechanism for the enzyme in which the ethylnitronate intermediate formed from the H196-catalyzed deprotonation of nitroethane partitions between release from the active site and oxidative denitrification to yield acetaldehyde and nitrite. PMID:18690716

  16. Eucalyptus ESTs involved in the production of 9-cis epoxycarotenoid dioxygenase, a regulatory enzyme of abscisic acid production

    Directory of Open Access Journals (Sweden)

    Iraê A. Guerrini

    2005-01-01

    Full Text Available Abscisic acid (ABA regulates stress responses in plants, and genomic tools can help us to understand the mechanisms involved in that process. FAPESP, a Brazilian research foundation, in association with four private forestry companies, has established the FORESTs database (https://forests.esalq.usp.br. A search was carried out in the Eucalyptus expressed sequence tag database to find ESTs involved with 9-cis epoxycarotenoid dioxygenase (NCED, the regulatory enzyme for ABA biosynthesis, using the basic local BLAST alignment tool. We found four clusters (EGEZLV2206B11.g, EGJMWD2252H08.g, EGBFRT3107F10.g, and EGEQFB1200H10.g, which represent similar sequences of the gene that produces NCED. Data showed that the EGBFRT3107F10.g cluster was similar to the maize (Zea mays NCED enzyme, while EGEZLV2206B11.g and EGJMWD2252H08.g clusters were similar to the avocado (Persea americana NCED enzyme. All Eucalyptus clusters were expressed in several tissues, especially in flower buds, where ABA has a special participation during the floral development process.

  17. Eosinophil Granulocytes Account for Indoleamine 2,3-Dioxygenase-Mediated Immune Escape in Human Non Small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Simonetta Astigiano

    2005-04-01

    Full Text Available Indoleamine 2,3-dioxygenase (IDO, a catabolizing enzyme of tryptophan, is supposed to play a role in tumor immune escape. Its expression in solid tumors has not yet been well elucidated: IDO can be expressed by the tumor cells themselves, or by ill-defined infiltrating cells, possibly depending on tumor type. We have investigated IDO expression in 25 cases of non small cell lung cancer (NSCLC. Using histochemistry and immunohistochemistry, we found that IDO was expressed not by tumor cells, but by normal cells infiltrating the peritumoral stroma. These cells were neither macrophages nor dendritic cells, and were identified as eosinophil granulocytes. The amount of IDO-positive eosinophils varied in different cases, ranging from a few cells to more than 50 per field at x200 magnification. IDO protein in NSCLC was enzymatically active. Therefore, at least in NSCLC cases displaying a large amount of these cells in the inflammatory infiltrate, IDO-positive eosinophils could exert an effective immunosuppressive action. On analyzing the 17 patients with adequate follow-up, a significant relationship was found between the amount of IDO-positive infiltrate and overall survival. This finding suggests that the degree of IDO-positive infiltrate could be a prognostic marker in NSCLC.

  18. Relationship of Abortion and the Expression of Indoleamine 2,3- dioxygenase (IDO) in Villus and Syncytiotrophoblasts

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective To study the relationship of abortion and the expression of indoleamine 2,3- dioxygenase (IDO) in villus and syncytiotrophoblast in vitro.Methods RT-PCR was applied to analyze the mRNA transcription of IDO in villus of normal pregnancy and inevitable abortion and JAR cells as well. Immunohistochemistry was applied to analyze the expression of IDO protein in villus. Western blot was applied to determinate the expression of IDO protein on cultured syncytiotrophoblast. Highperformance liquid chromatography was applied to determinate whether there was kynurenine in cell culture medium of syncytiotrophoblast.Results The expression of IDO mRNA and protein in villus of inevitable abortion was lower than that of normal pregnancy; IDO mRNA did not express in JAR cells. IDO protein expressed on cultured syncytiotrophoblast, and there was kynurenine in cell culture medium of syncytiotrophoblast.Conclusion Appropriate expression of IDO in villus is necessary for maintenance of normal pregnancy and an active IDO protein expresses in syncytiotrophoblast.

  19. Mitochondrial localization of the OAS1 p46 isoform associated with a common single nucleotide polymorphism

    DEFF Research Database (Denmark)

    Kjær, Karina Hansen; Pahus, Jytte; Hansen, Mariann Fagernæs;

    2014-01-01

    genotypes in the OAS1 SNP rs10774671, HeLa cells with the AA genotype, HT1080 cells with AG, and Daudi cells with GG. The main OAS1 isoform expressed in Daudi and HT1080 cells was p46, and the main OAS1 isoform expressed in HeLa cells was p42. In addition, low levels of the OAS1 p52 mRNA was detected in He...... vacuoles/lysosomes. By using recombinantly expressed OAS1 mutant proteins, we found that the OAS1 SNP rs1131454 (former rs3741981) did not affect the enzymatic OAS1 activity. Conclusions: The SNP rs10774671 determines differential expression of the OAS1 isoforms. In Daudi and HT1080 cells the p46 isoform...

  20. Glial fibrillary acidic protein isoform expression in plaque related astrogliosis in Alzheimer's disease

    NARCIS (Netherlands)

    Kamphuis, W.; Middeldorp, Jinte; Kooijman, Lieneke; Sluijs, Jacqueline A; Kooi, Evert-Jan; Moeton, Martina; Freriks, Michel; Mizee, Mark R; Hol, Elly M

    2014-01-01

    In Alzheimer's disease (AD), amyloid plaques are surrounded by reactive astrocytes with an increased expression of intermediate filaments including glial fibrillary acidic protein (GFAP). Different GFAP isoforms have been identified that are differentially expressed by specific subpopulations of ast

  1. Enhanced protein electrophoresis technique for separating human skeletal muscle myosin heavy chain isoforms

    Science.gov (United States)

    Bamman, M. M.; Clarke, M. S.; Talmadge, R. J.; Feeback, D. L.

    1999-01-01

    Talmadge and Roy (J. Appl. Physiol. 1993, 75, 2337-2340) previously established a sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) protocol for separating all four rat skeletal muscle myosin heavy chain (MHC) isoforms (MHC I, IIa, IIx, IIb); however, when applied to human muscle, the type II MHC isoforms (Ila, IIx) are not clearly distinguished. In this brief paper we describe a modification of the SDS-PAGE protocol which yields distinct and consistent separation of all three adult human MHC isoforms (MHC I, IIa, IIx) in a minigel system. MHC specificity of each band was confirmed by Western blot using three monoclonal IgG antibodies (mAbs) immunoreactive against MHCI (mAb MHCs, Novacastra Laboratories), MHCI+IIa (mAb BF-35), and MHCIIa+IIx (mAb SC-71). Results provide a valuable SDS-PAGE minigel technique for separating MHC isoforms in human muscle without the difficult task of casting gradient gels.

  2. Development of isoform-specific sensors of polypeptide GalNAc-transferase activity

    DEFF Research Database (Denmark)

    Song, Lina; Bachert, Collin; Schjoldager, Katrine T;

    2014-01-01

    Humans express up to 20 isoforms of GalNAc-transferase (herein T1-T20) that localize to the Golgi apparatus and initiate O-glycosylation. Regulation of this enzyme family affects a vast array of proteins transiting the secretory pathway and diseases arise upon misregulation of specific isoforms....... Surprisingly, molecular probes to monitor GalNAc-transferase activity are lacking and there exist no effective global or isoform-specific inhibitors. Here we describe the development of T2- and T3-isoform specific fluorescence sensors that traffic in the secretory pathway. Each sensor yielded little signal...... in both the study of GalNAc-transferase regulation and in high-throughput screening for potential therapeutic regulators of specific GalNAc-transferases....

  3. Receptor-isoform-selective insulin analogues give tissue-preferential effects

    DEFF Research Database (Denmark)

    Vienberg, Sara Gry; Bouman, Stephan D; Sørensen, Heidi;

    2011-01-01

    The relative expression patterns of the two IR (insulin receptor) isoforms, +/- exon 11 (IR-B/IR-A respectively), are tissue-dependent. Therefore we have developed insulin analogues with different binding affinities for the two isoforms to test whether tissue-preferential biological effects can...... be attained. In rats and mice, IR-B is the most prominent isoform in the liver (> 95%) and fat (> 90%), whereas in muscles IR-A is the dominant isoform (> 95%). As a consequence, the insulin analogue INS-A, which has a higher relative affinity for human IR-A, had a higher relative potency [compared with HI...... (human insulin)] for glycogen synthesis in rat muscle strips (26%) than for glycogen accumulation in rat hepatocytes (5%) and for lipogenesis in rat adipocytes (4%). In contrast, the INS-B analogue, which has an increased affinity for human IR-B, had higher relative potencies (compared with HI...

  4. VAMP/synaptobrevin isoforms 1 and 2 are widely and differentially expressed in nonneuronal tissues

    Science.gov (United States)

    1996-01-01

    VAMP/synaptobrevin is part of the synaptic vesicle docking and fusion complex and plays a central role in neuroexocytosis. Two VAMP (vesicle- associated membrane protein) isoforms are expressed in the nervous system and are differently distributed among the specialized parts of the tissue. Here, VAMP-1 and -2 are shown to be present in all rat tissues tested, including kidney, adrenal gland, liver, pancreas, thyroid, heart, and smooth muscle. The two isoforms are differentially expressed in various tissues and their level may depend on differentiation. VAMP-1 is restricted to exocrine pancreas and to kidney tubular cells, whereas VAMP-2 is the predominant isoform present in Langerhans islets and in glomerular cells. Both isoforms show a patchy vesicular intracellular distribution in confocal microscopy. The present results provide evidence for the importance of neuronal VAMP proteins in the physiology of all cells. PMID:8567721

  5. Patchwork assembly of nag-like nitroarene dioxygenase genes and the 3-chlorocatechol degradation cluster for evolution of the 2-chloronitrobenzene catabolism pathway in Pseudomonas stutzeri ZWLR2-1.

    Science.gov (United States)

    Liu, Hong; Wang, Shu-Jun; Zhang, Jun-Jie; Dai, Hui; Tang, Huiru; Zhou, Ning-Yi

    2011-07-01

    Pseudomonas stutzeri ZWLR2-1 utilizes 2-chloronitrobenzene (2CNB) as a sole source of carbon, nitrogen, and energy. To identify genes involved in this pathway, a 16.2-kb DNA fragment containing putative 2CNB dioxygenase genes was cloned and sequenced. Of the products from the 19 open reading frames that resulted from this fragment, CnbAc and CnbAd exhibited striking identities to the respective α and β subunits of the Nag-like ring-hydroxylating dioxygenases involved in the metabolism of nitrotoluene, nitrobenzene, and naphthalene. The encoding genes were also flanked by two copies of insertion sequence IS6100. CnbAa and CnbAb are similar to the ferredoxin reductase and ferredoxin for anthranilate 1,2-dioxygenase from Burkholderia cepacia DBO1. Escherichia coli cells expressing cnbAaAbAcAd converted 2CNB to 3-chlorocatechol with concomitant nitrite release. Cell extracts of E. coli/pCNBC exhibited chlorocatechol 1,2-dioxygenase activity. The cnbCDEF gene cluster, homologous to a 3-chlorocatechol degradation cluster in Sphingomonas sp. strain TFD44, probably contains all of the genes necessary for the conversion of 3-chlorocatechol to 3-oxoadipate. The patchwork-like structure of this catabolic cluster suggests that the cnb cluster for 2CNB degradation evolved by recruiting two catabolic clusters encoding a nitroarene dioxygenase and a chlorocatechol degradation pathway. This provides another example to help elucidate the bacterial evolution of catabolic pathways in response to xenobiotic chemicals.

  6. The cytoplasmic 60 kDa progesterone receptor isoform predominates in the human amniochorion and placenta at term

    Directory of Open Access Journals (Sweden)

    Bell Stephen C

    2009-03-01

    Full Text Available Abstract Background The mechanism that initiates human parturition has been proposed to be 'functional progesterone withdrawal' whereby the 116 kDa B-isoform of the progesterone receptor (PR-B switches in favour of the 94 kDa A-isoform (PR-A in reproductive tissues. Recently, other PR isoforms, PR-S, PR-C and PR-M generated from the same gene have been identified and partially characterised. Methods and Results Using immunohistochemical, western blotting and RT-PCR techniques, evidence is provided that indicates the major PR isoform present in human term fetal membranes (amnion and chorion and syncytiotrophoblast of the placenta is neither of the classical nuclear PR-B or PR-A isoforms but is the N-terminally truncated 60 kDa PR-C isoform. Evidence is also provided that this 60 kDa isoform resides in the cytoplasm of the expressing cell types. Data are also presented to show that PR-B, PR-A and PR-S isoforms are essentially absent from the amnion and chorion, whereas PR isoforms A, B, C and S are all present in the decidua, with PR-A being the major isoform. The syncytiotrophoblast of the placenta contains the cytoplasmic 60 kDa isoform, but not isoforms PR-A, PR-B or PR-S. Conclusion The major PR isoform in the amnion, chorion and placenta is a 60 kDa protein that could be PR-C, suggesting that the cytoplasmic isoform has a specific role in extra-embryonic tissues and may be involved in the regulation of human parturition.

  7. The impact of tropomyosins on actin filament assembly is isoform specific.

    Science.gov (United States)

    Janco, Miro; Bonello, Teresa T; Byun, Alex; Coster, Adelle C F; Lebhar, Helene; Dedova, Irina; Gunning, Peter W; Böcking, Till

    2016-07-01

    Tropomyosin (Tpm) is an α helical coiled-coil dimer that forms a co-polymer along the actin filament. Tpm is involved in the regulation of actin's interaction with binding proteins as well as stabilization of the actin filament and its assembly kinetics. Recent studies show that multiple Tpm isoforms also define the functional properties of distinct actin filament populations within a cell. Subtle structural variations within well conserved Tpm isoforms are the key to their functional specificity. Therefore, we purified and characterized a comprehensive set of 8 Tpm isoforms (Tpm1.1, Tpm1.12, Tpm1.6, Tpm1.7, Tpm1.8, Tpm2.1, Tpm3.1, and Tpm4.2), using well-established actin co-sedimentation and pyrene fluorescence polymerization assays. We observed that the apparent affinity (Kd(app)) to filamentous actin varied in all Tpm isoforms between ∼0.1-5 μM with similar values for both, skeletal and cytoskeletal actin filaments. The data did not indicate any correlation between affinity and size of Tpm molecules, however high molecular weight (HMW) isoforms Tpm1.1, Tpm1.6, Tpm1.7 and Tpm2.1, showed ∼3-fold higher cooperativity compared to low molecular weight (LMW) isoforms Tpm1.12, Tpm1.8, Tpm3.1, and Tpm4.2. The rate of actin filament elongation in the presence of Tpm2.1 increased, while all other isoforms decreased the elongation rate by 27-85 %. Our study shows that the biochemical properties of Tpm isoforms are finely tuned and depend on sequence variations in alternatively spliced regions of Tpm molecules. PMID:27420374

  8. Expression of Two Novel Alternatively Spliced COL2A1 Isoforms During Chondrocyte Differentiation

    OpenAIRE

    McAlinden, Audrey; Johnstone, Brian; Kollar, John; Kazmi, Najam; Hering, Thomas M.

    2007-01-01

    Alternative splicing of the type II procollagen gene (COL2A1) is developmentally-regulated during chondrogenesis. Type IIA procollagen (+ exon 2) is synthesized by chondroprogenitor cells while type IIB procollagen (- exon 2) is synthesized by differentiated chondrocytes. Here, we report expression of two additional alternatively spliced COL2A1 isoforms during chondrocyte differentiation of bone marrow derived mesenchymal stem cells (MSCs). One isoform, named IIC, contains only the first 34 n...

  9. Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches

    OpenAIRE

    Velten, Brandy P.; Welch, Kenneth C.

    2014-01-01

    Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25–60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to...

  10. Progesterone receptor isoform A may regulate the effects of neoadjuvant aglepristone in canine mammary carcinoma

    OpenAIRE

    Guil-Luna, Silvia; Stenvang, Jan; Brünner, Nils; De Andrés, Francisco Javier; Rollón, Eva; Domingo, Víctor; Sánchez-Céspedes, Raquel; Millán, Yolanda; Mulas, Juana Martín de las

    2014-01-01

    Background Progesterone receptors play a key role in the development of canine mammary tumours, and recent research has focussed on their possible value as therapeutic targets using antiprogestins. Cloning and sequencing of the progesterone receptor gene has shown that the receptor has two isoforms, A and B, transcribed from a single gene. Experimental studies in human breast cancer suggest that the differential expression of progesterone receptor isoforms has implications for hormone therapy...

  11. Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution.

    Directory of Open Access Journals (Sweden)

    Niels Jacob Aachmann-Andersen

    Full Text Available The membrane-assisted isoform immunoassay (MAIIA quantitates erythropoietin (EPO isoforms as percentages of migrated isoforms (PMI. We evaluated the effect of recombinant human EPO (rhEPO on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13; high-dose Epoetin beta (30.000 IU on days 1, 2 and 3 and placebo on days 5, 7, 9, 11 and 13; or placebo on all days. PMI on days 4, 11 and 25 was determined by interaction of N-acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3 % (mean (SD. High-dose Epoetin beta decreased PMI on days 4 and 11 to 31.0 (4.2% (p<0.00001 and 45.2 (7.3% (p<0.00001. Low-dose Epoetin beta decreased PMI on days 4 and 11 to 46.0 (12.8% (p<0.00001 and 46.1 (10.4% (p<0.00001. In both rhEPO groups, PMI on day 25 was still decreased (high-dose Epoetin beta: 72.9 (19.4% (p=0.029; low-dose Epoetin beta: 73.1 (17.8% (p=0.039. In conclusion, Epoetin beta leaves a footprint in the plasma-EPO isoform pattern. MAIIA can detect changes in EPO isoform distribution up til at least three weeks after administration of Epoetin beta even though the total EPO concentration has returned to normal.

  12. Genomic organization and the tissue distribution of alternatively spliced isoforms of the mouse Spatial gene

    Directory of Open Access Journals (Sweden)

    Mattei Marie-Geneviève

    2004-07-01

    Full Text Available Abstract Background The stromal component of the thymic microenvironment is critical for T lymphocyte generation. Thymocyte differentiation involves a cascade of coordinated stromal genes controlling thymocyte survival, lineage commitment and selection. The "Stromal Protein Associated with Thymii And Lymph-node" (Spatial gene encodes a putative transcription factor which may be involved in T-cell development. In the testis, the Spatial gene is also expressed by round spermatids during spermatogenesis. Results The Spatial gene maps to the B3-B4 region of murine chromosome 10 corresponding to the human syntenic region 10q22.1. The mouse Spatial genomic DNA is organised into 10 exons and is alternatively spliced to generate two short isoforms (Spatial-α and -γ and two other long isoforms (Spatial-δ and -ε comprising 5 additional exons on the 3' site. Here, we report the cloning of a new short isoform, Spatial-β, which differs from other isoforms by an additional alternative exon of 69 bases. This new exon encodes an interesting proline-rich signature that could confer to the 34 kDa Spatial-β protein a particular function. By quantitative TaqMan RT-PCR, we have shown that the short isoforms are highly expressed in the thymus while the long isoforms are highly expressed in the testis. We further examined the inter-species conservation of Spatial between several mammals and identified that the protein which is rich in proline and positive amino acids, is highly conserved. Conclusions The Spatial gene generates at least five alternative spliced variants: three short isoforms (Spatial-α, -β and -γ highly expressed in the thymus and two long isoforms (Spatial-δ and -ε highly expressed in the testis. These alternative spliced variants could have a tissue specific function.

  13. Kinetics of local and systemic isoforms of serum amyloid A in bovine mastitic milk

    DEFF Research Database (Denmark)

    Jacobsen, Stine; Niewold, T.A.; Kornalijnslijper, E.;

    2005-01-01

    The aim of the present study was to characterise the serum amyloid A (SAA) response to intramammary inoculation of Escherichia coli and to examine the distribution of hepatically and extrahepatically pruduced SAA isoforms in plasma and milk fra cows with mastitis.......The aim of the present study was to characterise the serum amyloid A (SAA) response to intramammary inoculation of Escherichia coli and to examine the distribution of hepatically and extrahepatically pruduced SAA isoforms in plasma and milk fra cows with mastitis....

  14. The impact of tropomyosins on actin filament assembly is isoform specific.

    Science.gov (United States)

    Janco, Miro; Bonello, Teresa T; Byun, Alex; Coster, Adelle C F; Lebhar, Helene; Dedova, Irina; Gunning, Peter W; Böcking, Till

    2016-07-01

    Tropomyosin (Tpm) is an α helical coiled-coil dimer that forms a co-polymer along the actin filament. Tpm is involved in the regulation of actin's interaction with binding proteins as well as stabilization of the actin filament and its assembly kinetics. Recent studies show that multiple Tpm isoforms also define the functional properties of distinct actin filament populations within a cell. Subtle structural variations within well conserved Tpm isoforms are the key to their functional specificity. Therefore, we purified and characterized a comprehensive set of 8 Tpm isoforms (Tpm1.1, Tpm1.12, Tpm1.6, Tpm1.7, Tpm1.8, Tpm2.1, Tpm3.1, and Tpm4.2), using well-established actin co-sedimentation and pyrene fluorescence polymerization assays. We observed that the apparent affinity (Kd(app)) to filamentous actin varied in all Tpm isoforms between ∼0.1-5 μM with similar values for both, skeletal and cytoskeletal actin filaments. The data did not indicate any correlation between affinity and size of Tpm molecules, however high molecular weight (HMW) isoforms Tpm1.1, Tpm1.6, Tpm1.7 and Tpm2.1, showed ∼3-fold higher cooperativity compared to low molecular weight (LMW) isoforms Tpm1.12, Tpm1.8, Tpm3.1, and Tpm4.2. The rate of actin filament elongation in the presence of Tpm2.1 increased, while all other isoforms decreased the elongation rate by 27-85 %. Our study shows that the biochemical properties of Tpm isoforms are finely tuned and depend on sequence variations in alternatively spliced regions of Tpm molecules.

  15. Opposing effects of fructokinase C and A isoforms on fructose-induced metabolic syndrome in mice

    OpenAIRE

    Ishimoto, Takuji; Lanaspa, Miguel A.; MyPhuong T Le; Garcia, Gabriela E.; Diggle, Christine P; MacLean, Paul S.; Jackman, Matthew R.; Asipu, Aruna; Roncal-Jimenez, Carlos A.; Kosugi, Tomoki; Rivard, Christopher J.; Maruyama, Shoichi; Rodriguez-Iturbe, Bernardo; Sánchez-Lozada, Laura G.; Bonthron, David T.

    2012-01-01

    Fructose intake from added sugars correlates with the epidemic rise in obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Fructose intake also causes features of metabolic syndrome in laboratory animals and humans. The first enzyme in fructose metabolism is fructokinase, which exists as two isoforms, A and C. Here we show that fructose-induced metabolic syndrome is prevented in mice lacking both isoforms but is exacerbated in mice lacking fructokinase A. Fructokinase C is expr...

  16. Differential Contributions of Nonmuscle Myosin II Isoforms and Functional Domains to Stress Fiber Mechanics

    OpenAIRE

    Ching-Wei Chang; Sanjay Kumar

    2015-01-01

    While is widely acknowledged that nonmuscle myosin II (NMMII) enables stress fibers (SFs) to generate traction forces against the extracellular matrix, little is known about how specific NMMII isoforms and functional domains contribute to SF mechanics. Here we combine biophotonic and genetic approaches to address these open questions. First, we suppress the NMMII isoforms MIIA and MIIB and apply femtosecond laser nanosurgery to ablate and investigate the viscoelastic retraction of individual ...

  17. Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

    OpenAIRE

    Marion Schiengold; Lavínia Schwantes; Ribeiro, Maria F; Nívia Lothhammer; Gonzalez, Tatiana P.; Jose Artur Bogo Chies; Nardi, Nance B

    2006-01-01

    The multidrug resistance (MDR) phenotype is associated with the expression of P-glycoprotein (Pgp), coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different...

  18. Differential and Conditional Activation of PKC-Isoforms Dictates Cardiac Adaptation during Physiological to Pathological Hypertrophy

    OpenAIRE

    Shaon Naskar; Kaberi Datta; Arkadeep Mitra; Kanchan Pathak; Ritwik Datta; Trisha Bansal; Sagartirtha Sarkar

    2014-01-01

    A cardiac hypertrophy is defined as an increase in heart mass which may either be beneficial (physiological hypertrophy) or detrimental (pathological hypertrophy). This study was undertaken to establish the role of different protein kinase-C (PKC) isoforms in the regulation of cardiac adaptation during two types of cardiac hypertrophy. Phosphorylation of specific PKC-isoforms and expression of their downstream proteins were studied during physiological and pathological hypertrophy in 24 week ...

  19. Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles.

    Science.gov (United States)

    Oe, M; Ojima, K; Nakajima, I; Chikuni, K; Shibata, M; Muroya, S

    2016-08-01

    To clarify the relationship between myosin heavy chain (MyHC) isoforms and tropomyosin (TPM) isoforms in single fibers, 64 single fibers were isolated from each of bovine three muscles (masseter, semispinalis and semitendinosus). mRNA expressions of MyHC and TPM isoforms were analyzed by real-time PCR. All single fibers from the masseter expressed MyHC-slow. The fibers from the semispinalis expressed both MyHC-slow and 2a. The fibers from the semitendinosus expressed MyHC-slow, 2a and 2x. TPM-1 and TPM-2 were co-expressed in 2a and 2x type fibers, and TPM-2 and TPM-3 were co-expressed in slow type fibers. The expression pattern of TPM isoforms in each fiber type was similar between fibers isolated from different muscles. These results suggest that TPM-1 and TPM-3 isoforms correspond to the function of 2a or 2x type fibers and slow type fibers, respectively, with TPM-2 in common. Furthermore, the patterns of MyHC and TPM isoform combinations did not vary among single fibers isolated from the individual muscles examined. PMID:27105153

  20. Two novel human NUMB isoforms provide a potential link between development and cancer

    Directory of Open Access Journals (Sweden)

    Prudovsky Igor

    2010-12-01

    Full Text Available Abstract We previously identified four functionally distinct human NUMB isoforms. Here, we report the identification of two additional isoforms and propose a link between the expression of these isoforms and cancer. These novel isoforms, NUMB5 and NUMB6, lack exon 10 and are expressed in cells known for polarity and migratory behavior, such as human amniotic fluid cells, glioblastoma and metastatic tumor cells. RT-PCR and luciferase assays demonstrate that NUMB5 and NUMB6 are less antagonistic to NOTCH signaling than other NUMB isoforms. Immunocytochemistry analyses show that NUMB5 and NUMB6 interact and complex with CDC42, vimentin and the CDC42 regulator IQGAP1 (IQ (motif GTPase activating protein 1. Furthermore, the ectopic expression of NUMB5 and NUMB6 induces the formation of lamellipodia (NUMB5 and filopodia (NUMB6 in a CDC42- and RAC1-dependent manner. These results are complemented by in vitro and in vivo studies, demonstrating that NUMB5 and NUMB6 alter the migratory behavior of cells. Together, these novel isoforms may play a role in further understanding the NUMB function in development and cancer.

  1. Profiling alternatively spliced mRNA isoforms for prostate cancer classification

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    Fan Jian-Bing

    2006-04-01

    Full Text Available Abstract Background Prostate cancer is one of the leading causes of cancer illness and death among men in the United States and world wide. There is an urgent need to discover good biomarkers for early clinical diagnosis and treatment. Previously, we developed an exon-junction microarray-based assay and profiled 1532 mRNA splice isoforms from 364 potential prostate cancer related genes in 38 prostate tissues. Here, we investigate the advantage of using splice isoforms, which couple transcriptional and splicing regulation, for cancer classification. Results As many as 464 splice isoforms from more than 200 genes are differentially regulated in tumors at a false discovery rate (FDR of 0.05. Remarkably, about 30% of genes have isoforms that are called significant but do not exhibit differential expression at the overall mRNA level. A support vector machine (SVM classifier trained on 128 signature isoforms can correctly predict 92% of the cases, which outperforms the classifier using overall mRNA abundance by about 5%. It is also observed that the classification performance can be improved using multivariate variable selection methods, which take correlation among variables into account. Conclusion These results demonstrate that profiling of splice isoforms is able to provide unique and important information which cannot be detected by conventional microarrays.

  2. Role of acyl carrier protein isoforms in plant lipid metabolism: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Ohlrogge, J.B.

    1989-01-01

    Previous research from my lab has revealed that several higher plant species have multiple isoforms of acyl carrier protein (ACP) and therefore this trait appears highly conserved among higher plants. This level of conservation suggests that the existence of ACP isoforms is not merely the results of neutral gene duplications. We have developed techniques to examine a wider range of species. Acyl carrier proteins can be labelled very specifically and to high specific activity using H-palmitate and the E. coli enzyme acyl-ACP synthetase. Isoforms were then resolved by western blotting and native PAGE of H-palmitate labelled ACP's. Multiple isoforms of ACP were observed the leaf tissue of the monocots Avena sativa and Hordeum vulgare and dicots including Arabidopsis thallina, Cuphea wrightii, and Brassica napus. Lower vascular plants including the cycad, Dioon edule, Ginkgo biloba, the gymnosperm Pinus, the fern Anernia phyllitidis and Psilotum nudum, the most primitive known extant vascular plant, were also found to have multiple ACP isoforms as were the nonvascular liverwort, Marchantia and moss, Polytrichum. Therefore, the development of ACP isoforms occurred early in evolution. However, the uniellular alge Chlamydomonas and Dunaliella and the photosynthetic cyanobacteria Synechocystis and Agmnellum have only a single elecrophotetic form of ACP. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants.

  3. Characterization of 14-3-3 isoforms expressed in the Echinococcus granulosus pathogenic larval stage.

    Science.gov (United States)

    Teichmann, Aline; Vargas, Daiani M; Monteiro, Karina M; Meneghetti, Bruna V; Dutra, Cristine S; Paredes, Rodolfo; Galanti, Norbel; Zaha, Arnaldo; Ferreira, Henrique B

    2015-04-01

    The 14-3-3 protein family of eukaryotic regulators was studied in Echinococcus granulosus, the causative agent of cystic hydatid disease. These proteins mediate important cellular processes in eukaryotes and are expected to play important roles in parasite biology. Six isoforms of E. granulosus 14-3-3 genes and proteins (Eg14-3-3.1-6) were analyzed, and their phylogenetic relationships were established with bona fide 14-3-3 orthologous proteins from eukaryotic species. Eg14-3-3 isoforms with previous evidence of expression (Eg14-3-3.1-4) in E. granulosus pathogenic larval stage (metacestode) were cloned, and recombinant proteins were used for functional studies. These protein isoforms were detected in different components of E. granulosus metacestode, including interface components with the host. The roles that are played by Eg14-3-3 proteins in parasite biology were inferred from the repertoires of interacting proteins with each isoform, as assessed by gel overlay, cross-linking, and affinity chromatography assays. A total of 95 Eg14-3-3 protein ligands were identified by mass spectrometry. Eg14-3-3 isoforms have shared partners (44 proteins), indicating some overlapping functions; however, they also bind exclusive partners (51 proteins), suggesting Eg14-3-3 functional specialization. These ligand repertoires indicate the involvement of Eg14-3-3 proteins in multiple biochemical pathways in the E. granulosus metacestode and note some degree of isoform specialization.

  4. Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles.

    Science.gov (United States)

    Oe, M; Ojima, K; Nakajima, I; Chikuni, K; Shibata, M; Muroya, S

    2016-08-01

    To clarify the relationship between myosin heavy chain (MyHC) isoforms and tropomyosin (TPM) isoforms in single fibers, 64 single fibers were isolated from each of bovine three muscles (masseter, semispinalis and semitendinosus). mRNA expressions of MyHC and TPM isoforms were analyzed by real-time PCR. All single fibers from the masseter expressed MyHC-slow. The fibers from the semispinalis expressed both MyHC-slow and 2a. The fibers from the semitendinosus expressed MyHC-slow, 2a and 2x. TPM-1 and TPM-2 were co-expressed in 2a and 2x type fibers, and TPM-2 and TPM-3 were co-expressed in slow type fibers. The expression pattern of TPM isoforms in each fiber type was similar between fibers isolated from different muscles. These results suggest that TPM-1 and TPM-3 isoforms correspond to the function of 2a or 2x type fibers and slow type fibers, respectively, with TPM-2 in common. Furthermore, the patterns of MyHC and TPM isoform combinations did not vary among single fibers isolated from the individual muscles examined.

  5. C/EBPβ Isoforms Expression in the Rat Brain during the Estrous Cycle

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    Valeria Hansberg-Pastor

    2015-01-01

    Full Text Available The CCAAT/enhancer-binding protein beta (C/EBPβ is a transcription factor expressed in different areas of the brain that regulates the expression of several genes involved in cell differentiation and proliferation. This protein has three isoforms (LAP1, LAP2, and LIP with different transcription activation potential. The role of female sex hormones in the expression pattern of C/EBPβ isoforms in the rat brain has not yet been described. In this study we demonstrate by western blot that the expression of the three C/EBPβ isoforms changes in different brain areas during the estrous cycle. In the cerebellum, LAP2 content diminished on diestrus and proestrus and LIP content diminished on proestrus and estrus days. In the prefrontal cortex, LIP content was higher on proestrus and estrus days. In the hippocampus, LAP isoforms presented a switch on diestrus day, since LAP1 content was the highest while that of LAP2 was the lowest. The LAP2 isoform was the most abundant one in all the three brain areas. The LAP/LIP ratio changed throughout the cycle and was tissue specific. These results suggest that C/EBPβ isoforms expression changes in a tissue-specific manner in the rat brain due to the changes in sex steroid hormone levels presented during the estrous cycle.

  6. Molecular modeling study on tunnel behavior in different histone deacetylase isoforms.

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    Sundarapandian Thangapandian

    Full Text Available Histone deacetylases (HDACs have emerged as effective therapeutic targets in the treatment of various diseases including cancers as these enzymes directly involved in the epigenetic regulation of genes. However the development of isoform-selective HDAC inhibitors has been a challenge till date since all HDAC enzymes possess conserved tunnel-like active site. In this study, using molecular dynamics simulation we have analyzed the behavior of tunnels present in HDAC8, 10, and 11 enzymes of class I, II, and IV, respectively. We have identified the equivalent tunnel forming amino acids in these three isoforms and found that they are very much conserved with subtle differences to be utilized in selective inhibitor development. One amino acid, methionine of HDAC8, among six tunnel forming residues is different in isoforms of other classes (glutamic acid (E in HDAC10 and leucine (L in HDAC 11 based on which mutations were introduced in HDAC11, the less studied HDAC isoform, to observe the effects of this change. The HDAC8-like (L268M mutation in the tunnel forming residues has almost maintained the deep and narrow tunnel as present in HDAC8 whereas HDAC10-like (L268E mutation has changed the tunnel wider and shallow as observed in HDAC10. These results explained the importance of the single change in the tunnel formation in different isoforms. The observations from this study can be utilized in the development of isoform-selective HDAC inhibitors.

  7. Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

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    Marion Schiengold

    2006-01-01

    Full Text Available The multidrug resistance (MDR phenotype is associated with the expression of P-glycoprotein (Pgp, coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different phases of the estrous cycle. Additionally, females were ovariectomized, submitted to different hormone treatments, and their uterus was analyzed for the expression of mdr isoforms. The results show that in the adrenal gland and ovaries mdr1 is the main isoform during proestrus, and that progesterone or a combination of progesterone and estrogen induce the expression of all mdr isoforms in the uterus of ovariectomized females. We suggest that the functions of mdr1 and mdr3 are overlapping, that mdr3 may be the more efficient isoform in the detoxification function, and that mdr1 may be more closely related to the secretion of steroid hormones.

  8. Molecular characterization of human thyroid hormone receptor β isoform 4.

    Science.gov (United States)

    Moriyama, Kenji; Yamamoto, Hiroyuki; Futawaka, Kumi; Atake, Asami; Kasahara, Masato; Tagami, Tetsuya

    2016-01-01

    Thyroid hormone exerts a pleiotropic effect on development, differentiation, and metabolism through thyroid hormone receptor (TR). A novel thyroid hormone receptor β isoform (TRβ4) was cloned using PCR from a human pituitary cDNA library as a template. We report here the characterization of TRβ4 from a molecular basis. Temporal expression of TRβ4 during the fetal period is abundant in the brain and kidney, comparable with the adult pattern. Western blot analysis revealed that TRs are ubiquitination labile proteins, while TRβ1 is potentially stable. TRβ1, peroxisome proliferator-activated receptors (PPAR), and vitamin D receptor (VDR), which belong to class II transcription factors that function via the formation of heterodimeric complexes with retinoid X receptor (RXR), were suppressed by TRβ4 in a dose-dependent manner. Thus, TRβ4 exhibits ligand-independent transcriptional silencing, possibly as a substitute for dimerized RXR. In this study, TRβ1 and TRβ4 transcripts were detected in several cell lines. Quantitative RT-PCR assay showed that the expression of TRβ4 in human embryonic carcinoma cells of the testis was suppressed by sex hormone in a reciprocal manner to TRβ1. In contrast, TRβ4 was expressed under a high dose of triiodothyronine (T3) in a reciprocal manner to TRβ1. Finally, in transiently transfected NIH-3T3 cells, green fluorescence protein (GFP)-tagged TRβ4 was mostly nuclear in both the absence and the presence of T3. By mutating defined regions of both TRβs, we found that both TRβ1 and TRβ4 had altered nuclear/cytoplasmic distribution as compared with wild-type, and different to T3 and the nuclear receptor corepressor (NCoR). Thus, site-specific DNA binding is not essential for maintaining TRβs within the nucleus. PMID:26513165

  9. Expression of 14-3-3 protein isoforms in mouse oocytes, eggs and ovarian follicular development

    Directory of Open Access Journals (Sweden)

    De Santanu

    2012-01-01

    Full Text Available Abstract Background The 14-3-3 (YWHA proteins are a highly conserved, ubiquitously expressed family of proteins. Seven mammalian isoforms of 14-3-3 are known (β, γ, ε, ζ, η, τ and, σ. These proteins associate with many intracellular proteins involved in a variety of cellular processes including regulation of the cell cycle, metabolism and protein trafficking. We are particularly interested in the role of 14-3-3 in meiosis in mammalian eggs and the role 14-3-3 proteins may play in ovarian function. Therefore, we examined the expression of 14-3-3 proteins in mouse oocyte and egg extracts by Western blotting after polyacrylamide gel electrophoresis, viewed fixed cells by indirect immunofluorescence, and examined mouse ovarian cells by immunohistochemical staining to study the expression of the different 14-3-3 isoforms. Results We have determined that all of the mammalian 14-3-3 isoforms are expressed in mouse eggs and ovarian follicular cells including oocytes. Immunofluorescence confocal microscopy of isolated oocytes and eggs confirmed the presence of all of the isoforms with characteristic differences in some of their intracellular localizations. For example, some isoforms (β, ε, γ, and ζ are expressed more prominently in peripheral cytoplasm compared to the germinal vesicles in oocytes, but are uniformly dispersed within eggs. On the other hand, 14-3-3η is diffusely dispersed in the oocyte, but attains a uniform punctate distribution in the egg with marked accumulation in the region of the meiotic spindle apparatus. Immunohistochemical staining detected all isoforms within ovarian follicles, with some similarities as well as notable differences in relative amounts, localizations and patterns of expression in multiple cell types at various stages of follicular development. Conclusions We found that mouse oocytes, eggs and follicular cells within the ovary express all seven isoforms of the 14-3-3 protein. Examination of the

  10. Study of 'Redhaven' peach and its white-fleshed mutant suggests a key role of CCD4 carotenoid dioxygenase in carotenoid and norisoprenoid volatile metabolism

    Directory of Open Access Journals (Sweden)

    Tartarini Stefano

    2011-01-01

    Full Text Available Abstract Background Carotenoids are plant metabolites which are not only essential in photosynthesis but also important quality factors in determining the pigmentation and aroma of flowers and fruits. To investigate the regulation of carotenoid metabolism, as related to norisoprenoids and other volatile compounds in peach (Prunus persica L. Batsch., and the role of carotenoid dioxygenases in determining differences in flesh color phenotype and volatile composition, the expression patterns of relevant carotenoid genes and metabolites were studied during fruit development along with volatile compound content. Two contrasted cultivars, the yellow-fleshed 'Redhaven' (RH and its white-fleshed mutant 'Redhaven Bianca' (RHB were examined. Results The two genotypes displayed marked differences in the accumulation of carotenoid pigments in mesocarp tissues. Lower carotenoid levels and higher levels of norisoprenoid volatiles were observed in RHB, which might be explained by differential activity of carotenoid cleavage dioxygenase (CCD enzymes. In fact, the ccd4 transcript levels were dramatically higher at late ripening stages in RHB with respect to RH. The two genotypes also showed differences in the expression patterns of several carotenoid and isoprenoid transcripts, compatible with a feed-back regulation of these transcripts. Abamine SG - an inhibitor of CCD enzymes - decreased the levels of both isoprenoid and non-isoprenoid volatiles in RHB fruits, indicating a complex regulation of volatile production. Conclusions Differential expression of ccd4 is likely to be the major determinant in the accumulation of carotenoids and carotenoid-derived volatiles in peach fruit flesh. More in general, dioxygenases appear to be key factors controlling volatile composition in peach fruit, since abamine SG-treated 'Redhaven Bianca' fruits had strongly reduced levels of norisoprenoids and other volatile classes. Comparative functional studies of peach carotenoid

  11. Respiratory Syncytial Virus-Infected Mesenchymal Stem Cells Regulate Immunity via Interferon Beta and Indoleamine-2,3-Dioxygenase

    Science.gov (United States)

    Cheung, Michael B.; Sampayo-Escobar, Viviana; Green, Ryan; Moore, Martin L.; Mohapatra, Subhra; Mohapatra, Shyam S.

    2016-01-01

    Respiratory syncytial virus (RSV) has been reported to infect human mesenchymal stem cells (MSCs) but the consequences are poorly understood. MSCs are present in nearly every organ including the nasal mucosa and the lung and play a role in regulating immune responses and mediating tissue repair. We sought to determine whether RSV infection of MSCs enhances their immune regulatory functions and contributes to RSV-associated lung disease. RSV was shown to replicate in human MSCs by fluorescence microscopy, plaque assay, and expression of RSV transcripts. RSV-infected MSCs showed differentially altered expression of cytokines and chemokines such as IL-1β, IL6, IL-8 and SDF-1 compared to epithelial cells. Notably, RSV-infected MSCs exhibited significantly increased expression of IFN-β (~100-fold) and indoleamine-2,3-dioxygenase (IDO) (~70-fold) than in mock-infected MSCs. IDO was identified in cytosolic protein of infected cells by Western blots and enzymatic activity was detected by tryptophan catabolism assay. Treatment of PBMCs with culture supernatants from RSV-infected MSCs reduced their proliferation in a dose dependent manner. This effect on PBMC activation was reversed by treatment of MSCs with the IDO inhibitors 1-methyltryptophan and vitamin K3 during RSV infection, a result we confirmed by CRISPR/Cas9-mediated knockout of IDO in MSCs. Neutralizing IFN-β prevented IDO expression and activity. Treatment of MSCs with an endosomal TLR inhibitor, as well as a specific inhibitor of the TLR3/dsRNA complex, prevented IFN-β and IDO expression. Together, these results suggest that RSV infection of MSCs alters their immune regulatory function by upregulating IFN-β and IDO, affecting immune cell proliferation, which may account for the lack of protective RSV immunity and for chronicity of RSV-associated lung diseases such as asthma and COPD. PMID:27695127

  12. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine 200.

    Science.gov (United States)

    Kovaleva, Elena G; Rogers, Melanie S; Lipscomb, John D

    2015-09-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady-state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures determined at 1.35-1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild-type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second-sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in the steric bulk and charge of the residue at position 200 appear to be capable of altering the rate-limiting step in catalysis and, perhaps, the nature of the reactive species. PMID:26267790

  13. Intron retention and rhythmic diel pattern regulation of carotenoid cleavage dioxygenase 2 during crocetin biosynthesis in saffron.

    Science.gov (United States)

    Ahrazem, Oussama; Rubio-Moraga, Angela; Argandoña-Picazo, Javier; Castillo, Raquel; Gómez-Gómez, Lourdes

    2016-06-01

    The carotenoid cleavage dioxygenase 2, a new member of the CCD family, catalyzes the conversion of zeaxanthin into crocetin-dialdehyde in Crocus. CCD2 is expressed in flowers, being responsible for the yellow, orange and red colorations displayed by tepals and stigma. Three CsCCD2 genes were identified in Crocus sativus, the longest contains ten exons and the shorter is a truncated copy with no introns and which lacks one exon sequence. Analysis of RNA-seq datasets of three developmental stages of saffron stigma allowed the determination of alternative splicing in CsCCD2, being intron retention (IR) the prevalent form of alternative splicing in CsCCD2. Further, high IR was observed in tissues that do not accumulate crocetin. The analysis of one CsCCD2 promoter showed cis-regulatory motifs involved in the response to light, temperature, and circadian regulation. The light and circadian regulation are common elements shared with the previously characterized CsLycB2a promoter, and these shared common cis-acting elements may represent binding sites for transcription factors responsible for co-regulation of these genes during the development of the stigma in saffron. A daily coordinated rhythmic regulation for CsCCD2 and CsLycB2a was observed, with higher levels of mRNA occurring at low temperatures during darkness, confirming the results obtained in the in silico promoter analysis. In addition, to the light and temperature dependent regulation of CsCCD2 expression, the apocarotenoid β-cyclocitral up-regulated CsCCD2 expression and could acts as a mediator of chromoplast-to-nucleus signalling, coordinating the expression of CsCCD2 with the developmental state of the chromoplast in the developing stigma. PMID:27071403

  14. The cystine/glutamate antiporter regulates indoleamine 2,3-dioxygenase protein levels and enzymatic activity in human dendritic cells.

    Science.gov (United States)

    Mattox, Mildred L; D'Angelo, June A; Grimes, Zachary M; Fiebiger, Edda; Dickinson, Bonny L

    2012-11-30

    Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the tryptophan-catabolizing pathway and a key regulator of peripheral immune tolerance. As the suppressive effects of IDO are predominantly mediated by dendritic cells (DCs) and IDO-competent DCs promote long-term immunologic tolerance, a detailed understanding of how IDO expression and activity is regulated in these cells is central to the rational design of therapies to induce robust immune tolerance. We previously reported that the cystine/glutamate antiporter modulates the functional expression of IDO in human monocyte-derived DCs. Specifically, we showed that blocking antiporter uptake of cystine significantly increased both IDO mRNA and IDO enzymatic activity and that this correlated with impaired DC presentation of exogenous antigen to T cells via MHC class II and the cross-presentation pathway. The antiporter regulates intracellular and extracellular redox by transporting cystine into the cell in exchange for glutamate. Intracellular cystine is reduced to cysteine to support biosynthesis of the major cellular antioxidant glutathione and cysteine is exported from the cell where it functions as an extracellular antioxidant. Here we show that antiporter control of IDO expression in DCs is reversible, independent of interferon-γ, regulated by redox, and requires active protein synthesis. These findings highlight a role for antiporter regulation of cellular redox as a critical control point for modulating IDO expression and activity in DCs. Thus, systemic disease and aging, processes that perturb redox homeostasis, may adversely affect immunity by promoting the generation of IDO-competent DCs.

  15. Role of 9-Lipoxygenase and α-Dioxygenase Oxylipin Pathways as Modulators of Local and Systemic Defense

    Institute of Scientific and Technical Information of China (English)

    Jorge Vicente; Tomás Cascón; Begonya Vicedo; Pilar García-Agustín; Mats Hamberg; Carmen Castresana

    2012-01-01

    Plant 9-lipoxygenases(9-LOX)and α-dioxygenases(α-DOX)initiate the synthesis of oxylipins after bacterial infection.Here,the role of these enzymes in plants' defense was investigated using individual Arabidopsis thaliana lox1 and dox1 mutants and a double lox1 dox1 mutant.Studies with Pseudomonas syringae pv.tomato(Pst)revealed the enhanced susceptibility of lox1 to the virulent strain Pst DC3000 and the partial impairment of lox1 and dox1 mutants to activate systemic acquired resistance.Notably,both defects were enhanced in the lox1 dox1 plants as compared with individual mutants.We found that pre-treatment with 9-LOX- and α-DOX-generated oxylipins protected plant tissues against bacterial infection.The strongest effect in this respect was exerted by 9-ketooctadecatrienoic acid(9-KOT),which is produced from linolenic acid by 9-LOX.Quantification of 9-KOT revealed its accumulation after bacterial infection.The levels were reduced in lox1 and lox1 dox1 plants but strongly increased in the dox1 mutant due to metabolic interaction of the two pathways.Transcriptional analyses indicated that 9-KOT pre-treatment modifies hormone homeostasis during bacterial infection.The nature of the changes detected suggested that 9-KOT interferes with the hormonal changes caused by bacterial effectors.This notion was substantiated by the finding that 9-KOT failed to reduce the growth of PstDC3000hrpA,a mutant compromised in effector secretion,and of the avirulent strain Pst DC3000 avrRpm1.Further support for the action of the 9-LOX- and α-DOX-oxylipin pathways as modulators of hormone homeostasis was the observation that lox1 dox1 seedlings are hypersensitive to the growth-inhibitory effect of ABA and showed enhanced activation of ABA-inducible marker genes as compared with wild-type plants.

  16. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine-200

    Science.gov (United States)

    Kovaleva, Elena G.; Rogers, Melanie S.; Lipscomb, John D.

    2015-01-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures solved at 1.35 –1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in steric bulk and charge of the residue at position 200 appear capable of altering the rate-limiting step in catalysis, and perhaps, the nature of the reactive species. PMID:26267790

  17. Purification and Characterization of Catechol 1,2-Dioxygenase from Acinetobacter sp. Y64 Strain and Escherichia coli Transformants.

    Science.gov (United States)

    Lin, J; Milase, R N

    2015-12-01

    This study intends to purify and characterize catechol 1,2-dioxygenase (C1,2O) of phenol-degrading Acinetobacter sp. Y64 and of E. coli transformant. Acinetobacter sp. Y64 was capable of degrading 1000 mg/L of phenol within 14 ± 2 h at 30 °C, 160 rpm and pH of 7. One C1,2O of 36 kDa was purified using ammonium sulphate precipitation and Hitrap QFF column chromatograph with 49% recovery and a 10.6-fold increase in purity. Purified Y64 C1,2O had temperature and pH optimum at 37 °C and pH 7.7 respectively with the Michaelis constant of 17.53 µM and the maximal velocity of 1.95 U/mg, respectively. The presence of Fe(3+) or Fe(2+) enhanced the activity of Y64 C1,2O while other compounds such as Ca(2+), and EDTA had an inhibitory effect. 80% of C1,2O activity remained using 4-nitrocatechol as substrate while 2% remained using 3-methylcatechol compared with that using catechol. Y64 catA gene encoding C1,2O was amplified using PCR cloned into pET22b vector and expressed in Escherichia coli BL21 DE3 (pLysS) after transformation. Purified and cloned Y64 C1,2O show no significant differences in the biochemical properties. The phylogenetic tree based on the protein sequences indicates that these C1,2Os possess a common ancestry.

  18. Structural Basis for Substrate and Oxygen Activation in Homoprotocatechuate 2,3-Dioxygenase: Roles of Conserved Active Site Histidine 200.

    Science.gov (United States)

    Kovaleva, Elena G; Rogers, Melanie S; Lipscomb, John D

    2015-09-01

    Kinetic and spectroscopic studies have shown that the conserved active site residue His200 of the extradiol ring-cleaving homoprotocatechuate 2,3-dioxygenase (FeHPCD) from Brevibacterium fuscum is critical for efficient catalysis. The roles played by this residue are probed here by analysis of the steady-state kinetics, pH dependence, and X-ray crystal structures of the FeHPCD position 200 variants His200Asn, His200Gln, and His200Glu alone and in complex with three catecholic substrates (homoprotocatechuate, 4-sulfonylcatechol, and 4-nitrocatechol) possessing substituents with different inductive capacity. Structures determined at 1.35-1.75 Å resolution show that there is essentially no change in overall active site architecture or substrate binding mode for these variants when compared to the structures of the wild-type enzyme and its analogous complexes. This shows that the maximal 50-fold decrease in kcat for ring cleavage, the dramatic changes in pH dependence, and the switch from ring cleavage to ring oxidation of 4-nitrocatechol by the FeHPCD variants can be attributed specifically to the properties of the altered second-sphere residue and the substrate. The results suggest that proton transfer is necessary for catalysis, and that it occurs most efficiently when the substrate provides the proton and His200 serves as a catalyst. However, in the absence of an available substrate proton, a defined proton-transfer pathway in the protein can be utilized. Changes in the steric bulk and charge of the residue at position 200 appear to be capable of altering the rate-limiting step in catalysis and, perhaps, the nature of the reactive species.

  19. Purification and Characterization of Catechol 1,2-Dioxygenase from Acinetobacter sp. Y64 Strain and Escherichia coli Transformants.

    Science.gov (United States)

    Lin, J; Milase, R N

    2015-12-01

    This study intends to purify and characterize catechol 1,2-dioxygenase (C1,2O) of phenol-degrading Acinetobacter sp. Y64 and of E. coli transformant. Acinetobacter sp. Y64 was capable of degrading 1000 mg/L of phenol within 14 ± 2 h at 30 °C, 160 rpm and pH of 7. One C1,2O of 36 kDa was purified using ammonium sulphate precipitation and Hitrap QFF column chromatograph with 49% recovery and a 10.6-fold increase in purity. Purified Y64 C1,2O had temperature and pH optimum at 37 °C and pH 7.7 respectively with the Michaelis constant of 17.53 µM and the maximal velocity of 1.95 U/mg, respectively. The presence of Fe(3+) or Fe(2+) enhanced the activity of Y64 C1,2O while other compounds such as Ca(2+), and EDTA had an inhibitory effect. 80% of C1,2O activity remained using 4-nitrocatechol as substrate while 2% remained using 3-methylcatechol compared with that using catechol. Y64 catA gene encoding C1,2O was amplified using PCR cloned into pET22b vector and expressed in Escherichia coli BL21 DE3 (pLysS) after transformation. Purified and cloned Y64 C1,2O show no significant differences in the biochemical properties. The phylogenetic tree based on the protein sequences indicates that these C1,2Os possess a common ancestry. PMID:26563518

  20. Induction of indoleamine 2, 3-dioxygenase in human dendritic cells by a cholera toxin B subunit-proinsulin vaccine.

    Directory of Open Access Journals (Sweden)

    Jacques C Mbongue

    Full Text Available Dendritic cells (DC interact with naïve T cells to regulate the delicate balance between immunity and tolerance required to maintain immunological homeostasis. In this study, immature human dendritic cells (iDC were inoculated with a chimeric fusion protein vaccine containing the pancreatic β-cell auto-antigen proinsulin linked to a mucosal adjuvant the cholera toxin B subunit (CTB-INS. Proteomic analysis of vaccine inoculated DCs revealed strong up-regulation of the tryptophan catabolic enzyme indoleamine 2, 3-dioxygenase (IDO1. Increased biosynthesis of the immunosuppressive enzyme was detected in DCs inoculated with the CTB-INS fusion protein but not in DCs inoculated with proinsulin, CTB, or an unlinked combination of the two proteins. Immunoblot and PCR analyses of vaccine treated DCs detected IDO1mRNA by 3 hours and IDO1 protein synthesis by 6 hours after vaccine inoculation. Determination of IDO1 activity in vaccinated DCs by measurement of tryptophan degradation products (kynurenines showed increased tryptophan cleavage into N-formyl kynurenine. Vaccination did not interfere with monocytes differentiation into DC, suggesting the vaccine can function safely in the human immune system. Treatment of vaccinated DCs with pharmacological NF-κB inhibitors ACHP or DHMEQ significantly inhibited IDO1 biosynthesis, suggesting a role for NF-κB signaling in vaccine up-regulation of dendritic cell IDO1. Heat map analysis of the proteomic data revealed an overall down-regulation of vaccinated DC functions, suggesting vaccine suppression of DC maturation. Together, our experimental data indicate that CTB-INS vaccine induction of IDO1 biosynthesis in human DCs may result in the inhibition of DC maturation generating a durable state of immunological tolerance. Understanding how CTB-INS modulates IDO1 activity in human DCs will facilitate vaccine efficacy and safety, moving this immunosuppressive strategy closer to clinical applications for prevention

  1. Prognostic Significance of Promoter DNA Hypermethylation of cysteine dioxygenase 1 (CDO1 Gene in Primary Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Naoko Minatani

    Full Text Available Using pharmacological unmasking microarray, we identified promoter DNA methylation of cysteine dioxygenase 1 (CDO1 gene in human cancer. In this study, we assessed the clinicopathological significance of CDO1 methylation in primary breast cancer (BC with no prior chemotherapy. The CDO1 DNA methylation was quantified by TaqMan methylation specific PCR (Q-MSP in 7 BC cell lines and 172 primary BC patients with no prior chemotherapy. Promoter DNA of the CDO1 gene was hypermethylated in 6 BC cell lines except SK-BR3, and CDO1 gene expression was all silenced at mRNA level in the 7 BC cell lines. Quantification of CDO1 methylation was developed using Q-MSP, and assessed in primary BC. Among the clinicopathologic factors, CDO1 methylation level was not statistically significantly associated with any prognostic factors. The log-rank plot analysis elucidated that the higher methylation the tumors harbored, the poorer prognosis the patients exhibited. Using the median value of 58.0 as a cut-off one, disease specific survival in BC patients with CDO1 hypermethylation showed significantly poorer prognosis than those with hypomethylation (p = 0.004. Multivariate Cox proportional hazards model identified that CDO1 hypermethylation was prognostic factor as well as Ki-67 and hormone receptor status. The most intriguingly, CDO1 hypermethylation was of robust prognostic relevance in triple negative BC (p = 0.007. Promoter DNA methylation of CDO1 gene was robust prognostic indicator in primary BC patients with no prior chemotherapy. Prognostic relevance of the CDO1 promoter DNA methylation is worthy of being paid attention in triple negative BC cancer.

  2. Indoleamine 2,3-dioxygenase 1 (IDO1 activity correlates with immune system abnormalities in multiple myeloma

    Directory of Open Access Journals (Sweden)

    Bonanno Giuseppina

    2012-12-01

    Full Text Available Abstract Background Multiple myeloma (MM is a plasma cell malignancy with a multifaceted immune dysfunction. Indoleamine 2,3-dioxygenase 1 (IDO1 degrades tryptophan into kynurenine (KYN, which inhibits effector T cells and promote regulatory T-cell (Treg differentiation. It is presently unknown whether MM cells express IDO1 and whether IDO1 activity correlates with immune system impairment. Methods We investigated IDO1 expression in 25 consecutive patients with symptomatic MM and in 7 patients with either monoclonal gammopathy of unknown significance (MGUS; n=3 or smoldering MM (SMM; n=4. IDO1-driven tryptophan breakdown was correlated with the release of hepatocyte growth factor (HGF and with the frequency of Treg cells and NY-ESO-1-specific CD8+ T cells. Results KYN was increased in 75% of patients with symptomatic MM and correlated with the expansion of CD4+CD25+FoxP3+ Treg cells and the contraction of NY-ESO-1-specific CD8+ T cells. In vitro, primary MM cells promoted the differentiation of allogeneic CD4+ T cells into bona fide CD4+CD25hiFoxP3hi Treg cells and suppressed IFN-γ/IL-2 secretion, while preserving IL-4 and IL-10 production. Both Treg expansion and inhibition of Th1 differentiation by MM cells were reverted, at least in part, by d,l-1-methyl-tryptophan, a chemical inhibitor of IDO. Notably, HGF levels were higher within the BM microenvironment of patients with IDO+ myeloma disease compared with patients having IDO- MM. Mechanistically, the antagonism of MET receptor for HGF with SU11274, a MET inhibitor, prevented HGF-induced AKT phosphorylation in MM cells and translated into reduced IDO protein levels and functional activity. Conclusions These data suggest that IDO1 expression may contribute to immune suppression in patients with MM and possibly other HGF-producing cancers.

  3. Structural investigations of the ferredoxin and terminal oxygenase components of the biphenyl 2,3-dioxygenase from Sphingobium yanoikuyae B1

    Directory of Open Access Journals (Sweden)

    Gibson David T

    2007-03-01

    Full Text Available Abstract Background The initial step involved in oxidative hydroxylation of monoaromatic and polyaromatic compounds by the microorganism Sphingobium yanoikuyae strain B1 (B1, previously known as Sphingomonas yanoikuyae strain B1 and Beijerinckia sp. strain B1, is performed by a set of multiple terminal Rieske non-heme iron oxygenases. These enzymes share a single electron donor system consisting of a reductase and a ferredoxin (BPDO-FB1. One of the terminal Rieske oxygenases, biphenyl 2,3-dioxygenase (BPDO-OB1, is responsible for B1's ability to dihydroxylate large aromatic compounds, such as chrysene and benzo[a]pyrene. Results In this study, crystal structures of BPDO-OB1 in both native and biphenyl bound forms are described. Sequence and structural comparisons to other Rieske oxygenases show this enzyme to be most similar, with 43.5 % sequence identity, to naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4. While structurally similar to naphthalene 1,2-dioxygenase, the active site entrance is significantly larger than the entrance for naphthalene 1,2-dioxygenase. Differences in active site residues also allow the binding of large aromatic substrates. There are no major structural changes observed upon binding of the substrate. BPDO-FB1 has large sequence identity to other bacterial Rieske ferredoxins whose structures are known and demonstrates a high structural homology; however, differences in side chain composition and conformation around the Rieske cluster binding site are noted. Conclusion This is the first structure of a Rieske oxygenase that oxidizes substrates with five aromatic rings to be reported. This ability to catalyze the oxidation of larger substrates is a result of both a larger entrance to the active site as well as the ability of the active site to accommodate larger substrates. While the biphenyl ferredoxin is structurally similar to other Rieske ferredoxins, there are distinct changes in the amino acids near

  4. Abundance of Novel and Diverse tfdA-Like Genes, Encoding Putative Phenoxyalkanoic Acid Herbicide-Degrading Dioxygenases, in Soil▿ †

    OpenAIRE

    Zaprasis, Adrienne; Liu, Ya-Jun; Liu, Shuang-Jiang; Drake, Harold L.; Horn, Marcus A.

    2009-01-01

    Phenoxyalkanoic acid (PAA) herbicides are widely used in agriculture. Biotic degradation of such herbicides occurs in soils and is initiated by α-ketoglutarate- and Fe2+-dependent dioxygenases encoded by tfdA-like genes (i.e., tfdA and tfdAα). Novel primers and quantitative kinetic PCR (qPCR) assays were developed to analyze the diversity and abundance of tfdA-like genes in soil. Five primer sets targeting tfdA-like genes were designed and evaluated. Primer sets 3 to 5 specifically amplified ...

  5. Long-lasting Disease Stabilization in the Absence of Toxicity in Metastatic Lung Cancer Patients Vaccinated with an Epitope Derived from Indoleamine 2,3 Dioxygenase

    DEFF Research Database (Denmark)

    Iversen, Trine Zeeberg; Engell-Noerregaard, Lotte; Ellebaek, Eva;

    2014-01-01

    PURPOSE: To investigate targeting of indoleamine 2,3 dioxygenase (IDO) enzyme using a synthetic peptide vaccine administered to patients with metastatic non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: In a clinical phase I study, we treated 15 HLA-A2-positive patients with stage III...... significant improved OS (P = 0.03) when compared with the group of patients excluded because of HLA-A2 negativity. IDO-specific CD8(+) T-cell immunity was demonstrated by IFN-γ Elispot and Tetramer staining. Fluorescence-activated cell sorting analyses demonstrated a significant reduction of the Treg...

  6. Identification of alternatively translated Tetherin isoforms with differing antiviral and signaling activities.

    Directory of Open Access Journals (Sweden)

    Luis J Cocka

    2012-09-01

    Full Text Available Tetherin (BST-2/CD317/HM1.24 is an IFN induced transmembrane protein that restricts release of a broad range of enveloped viruses. Important features required for Tetherin activity and regulation reside within the cytoplasmic domain. Here we demonstrate that two isoforms, derived by alternative translation initiation from highly conserved methionine residues in the cytoplasmic domain, are produced in both cultured human cell lines and primary cells. These two isoforms have distinct biological properties. The short isoform (s-Tetherin, which lacks 12 residues present in the long isoform (l-Tetherin, is significantly more resistant to HIV-1 Vpu-mediated downregulation and consequently more effectively restricts HIV-1 viral budding in the presence of Vpu. s-Tetherin Vpu resistance can be accounted for by the loss of serine-threonine and tyrosine motifs present in the long isoform. By contrast, the l-Tetherin isoform was found to be an activator of nuclear factor-kappa B (NF-κB signaling whereas s-Tetherin does not activate NF-κB. Activation of NF-κB requires a tyrosine-based motif found within the cytoplasmic tail of the longer species and may entail formation of l-Tetherin homodimers since co-expression of s-Tetherin impairs the ability of the longer isoform to activate NF-κB. These results demonstrate a novel mechanism for control of Tetherin antiviral and signaling function and provide insight into Tetherin function both in the presence and absence of infection.

  7. The relationships among bovine αS-casein phosphorylation isoforms suggest different phosphorylation pathways.

    Science.gov (United States)

    Fang, Z H; Visker, M H P W; Miranda, G; Delacroix-Buchet, A; Bovenhuis, H; Martin, P

    2016-10-01

    Casein (CN) phosphorylation is an important posttranslational modification and is one of the key factors responsible for constructing and stabilizing casein micelles. Variation in phosphorylation degree of αS-CN is of great interest because it is suggested to affect milk technological properties. This study aimed to investigate the variation in phosphorylation degree of αS-CN among milk of individual cows and to explore relationships among different phosphorylation isoforms of αS-CN. For this purpose, we analyzed morning milk samples from 529 French Montbéliarde cows using liquid chromatography coupled with electrospray ionization mass spectrometry. We detected 3 new phosphorylation isoforms: αS2-CN-9P, αS2-CN-14P, and αS2-CN-15P in bovine milk, in addition to the known isoforms αS1-CN-8P, αS1-CN-9P, αS2-CN-10P, αS2-CN-11P, αS2-CN-12P, and αS2-CN-13P. The relative concentrations of each αS-CN phosphorylation isoform varied considerably among individual cows. Furthermore, the phenotypic correlations and hierarchical clustering suggest at least 2 regulatory systems for phosphorylation of αS-CN: one responsible for isoforms with lower levels of phosphorylation (αS1-CN-8P, αS2-CN-10P, and αS2-CN-11P), and another responsible for isoforms with higher levels of phosphorylation (αS1-CN-9P, αS2-CN-12P, αS2-CN-13P, and αS2-CN-14P). Identifying all phosphorylation sites of αS2-CN and investigating the genetic background of different αS2-CN phosphorylation isoforms may provide further insight into the phosphorylation mechanism of caseins. PMID:27522420

  8. Transferrin and Its Isoforms from Normal Human Serum Revealed by Several Analytical Techniques

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Transferrin(TF) and its isoforms have been widely reported via various analytical techniques, including a noticeable increased number of isoforms with low content of sialic acid(asialo-, monosialo-, and disialo-transferrin) and asialo-TF as well as disialo-TF, with one or several oligosaccharides released in human serum transferrin(hTf). Here,hTf has been purified by native gradient polyacrylamide gel electrophoresis(PAGENG) before use. The hTf extracted with the electron-transfer approach showed a single subunit band(77.1 Da) in the SDS-PAGE gel, but it exhibited two bands in the native and denatured isoelectric focusing(IEF) gels, namely, hTf-2Fe3+ and apo-hTf, without finding any other transferrin isoforms. A reversed phase HPLC(RP-HPLC) equipped with a C18 column effectively separated hTf and its polymers and combined off-line techniques, including peptide mass fingerprinting(PMF), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) and database search, and identified the high homology among hTf, apo-hTf, and their isoforms. Moreover, the elution solution consisting of acetonitrile and formic acid could easily denature both hTf and apo-hTf to form various isoforms during separation with HPLC, indicating that chemical factors lead to the formation of various isoforms in transferrin, artificially, during extraction and separation.The authors claimed that only two transferrin isoforms existed in the NHS, namely, hTf-2Fe3+ and apo-hTf, which could be employed in biomarkers, to distinguish the healthy population from many disease sufferers, such as,carbohydrate-deficient transferrin(CDT).

  9. Differential CARM1 Isoform Expression in Subcellular Compartments and among Malignant and Benign Breast Tumors.

    Directory of Open Access Journals (Sweden)

    David Shlensky

    Full Text Available Coactivator-associated arginine methyltransferase 1 (CARM1 is a coactivator for ERα and cancer-relevant transcription factors, and can methylate diverse cellular targets including histones. CARM1 is expressed in one of two alternative splice isoforms, full-length CARM1 (CARM1FL and truncated CARM1 (CARM1ΔE15. CARM1FL and CARM1ΔE15 function differently in transcriptional regulation, protein methylation, and mediation of pre-mRNA splicing in cellular models.To investigate the functional roles and the prognosis potential of CARM1 alternative spliced isoforms in breast cancer, we used recently developed antibodies to detect differential CARM1 isoform expression in subcellular compartments and among malignant and benign breast tumors.Immunofluorescence in MDA-MB-231 and BG-1 cell lines demonstrated that CARM1ΔE15 is the dominant isoform expressed in the cytoplasm, and CARM1FL is more nuclear localized. CARM1ΔE15 was found to be more sensitive to Hsp90 inhibition than CARM1FL, indicating that the truncated isoform may be the oncogenic form. Clinical cancer samples did not have significantly higher expression of CARM1FL or CARM1ΔE15 than benign breast samples at the level of mRNA or histology. Furthermore neither CARM1FL nor CARM1ΔE15 expression correlated with breast cancer molecular subtypes, tumor size, or lymph node involvement.The analysis presented here lends new insights into the possible oncogenic role of CARM1ΔE15. This study also demonstrates no obvious association of CARM1 isoform expression and clinical correlates in breast cancer. Recent studies, however, have shown that CARM1 expression correlates with poor prognosis, indicating a need for further studies of both CARM1 isoforms in a large cohort of breast cancer specimens.

  10. Modeled microgravity-induced protein kinase C isoform expression in human lymphocytes

    Science.gov (United States)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    2004-01-01

    In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited in both microgravity and modeled microgravity (MMG) as reflected by diminished DNA synthesis in peripheral blood lymphocytes and their locomotion through gelled type I collagen. Direct activation of protein kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas the calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 1 g and MMG culture. Human lymphocytes were cultured and harvested at 24, 48, 72, and 96 h, and serial samples were assessed for locomotion by using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta, and -epsilon was assessed by RT-PCR, flow cytometry, and immunoblotting. Results indicated that PKC isoforms delta and epsilon were downregulated by >50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 1-g controls. Events upstream of PKC, such as phosphorylation of phospholipase Cgamma in MMG, revealed accumulation of inactive enzyme. Depressed calcium-independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than PKC, but after ligand-receptor interaction.

  11. Differential dynamics of RAS isoforms in GDP- and GTP-bound states.

    Science.gov (United States)

    Kapoor, Abhijeet; Travesset, Alex

    2015-06-01

    RAS subfamily proteins regulates cell growth promoting signaling processes by cycling between active (GTP-bound) and inactive (GDP-bound) states. Different RAS isoforms, though structurally similar, exhibit functional specificity and are associated with different types of cancers and developmental disorders. Understanding the dynamical differences between the isoforms is crucial for the design of inhibitors that can selectively target a particular malfunctioning isoform. In this study, we provide a comprehensive comparison of the dynamics of all the three RAS isoforms (HRAS, KRAS, and NRAS) using extensive molecular dynamics simulations in both the GDP- (total of 3.06 μs) and GTP-bound (total of 2.4 μs) states. We observed significant differences in the dynamics of the isoforms, which rather interestingly, varied depending on the type of the nucleotide bound and the simulation temperature. Both SwitchI (Residues 25-40) and SwitchII (Residues 59-75) differ significantly in their flexibility in the three isoforms. Furthermore, Principal Component Analysis showed that there are differences in the conformational space sampled by the GTP-bound RAS isoforms. We also identified a previously unreported pocket, which opens transiently during MD simulations, and can be targeted to regulate nucleotide exchange reaction or possibly interfere with membrane localization. Further, we present the first simulation study showing GDP destabilization in the wild-type RAS protein. The destabilization of GDP/GTP occurred only in 1/50 simulations, emphasizing the need of guanine nucleotide exchange factors (GEFs) to accelerate such an extremely unfavorable process. This observation along with the other results presented in this article further support our previously hypothesized mechanism of GEF-assisted nucleotide exchange.

  12. Two isoforms of trimming glucosidase II exist in mammalian tissues and cell lines but not in yeast and insect cells.

    Science.gov (United States)

    Ziak, M; Meier, M; Etter, K S; Roth, J

    2001-01-12

    We previously cloned glucosidase II and provided in vivo evidence for its involvement in protein folding quality control. DNA-sequencing of different clones demonstrated the existence of two isoforms of glucosidase II which differed by 66 nucleotides due to alternative splicing. The existence of two enzyme isoforms in various organs of pig and rat as well as human, bovine, rat, and mouse cell lines could be demonstrated by RT-PCR and Western blotting. Furthermore, the two isoforms of glucosidase II could be detected in embryonic and postnatal rat kidney and liver. In yeast, Saccharomyces cerevisiae, and in insects, Drosophila S2 cells, only one isoforms of the enzyme was detectable. The ubiquitous occurrence of the two glucosidase II isoforms in mammalian tissues and cell lines might be indicative of a special function of each isoform.

  13. Dichotomy of short and long thymic stromal lymphopoietin isoforms in inflammatory disorders of the bowel and skin

    Science.gov (United States)

    Fornasa, Giulia; Tsilingiri, Katerina; Caprioli, Flavio; Botti, Fiorenzo; Mapelli, Marina; Meller, Stephan; Kislat, Andreas; Homey, Bernhard; Di Sabatino, Antonio; Sonzogni, Angelica; Viale, Giuseppe; Diaferia, Giuseppe; Gori, Alessandro; Longhi, Renato; Penna, Giuseppe; Rescigno, Maria

    2015-01-01

    Background Thymic stromal lymphopoietin (TSLP) is a cytokine with pleiotropic functions in the immune system. It has been associated with allergic reactions in the skin and lungs but also homeostatic tolerogenic responses in the thymus and gut. Objective In human subjects TSLP is present in 2 isoforms, short and long. Here we wanted to investigate the differential expression of the TSLP isoforms and discern their biological implications under homeostatic or inflammatory conditions. Methods We evaluated the expression of TSLPs in tissues from healthy subjects, patients with ulcerative colitis, patients with celiac disease, and patients with atopic dermatitis and on epithelial cells and keratinocytes under steady-state conditions or after stimulation. We then tested the immune activity of TSLP isoforms both in vitro and in vivo. Results We showed that TSLP isoforms are responsible for 2 opposite immune functions. The short isoform is expressed under steady-state conditions and exerts anti-inflammatory activities by affecting the capacity of PBMCs and dendritic cells to produce inflammatory cytokines. Moreover, the short isoform TSLP ameliorates experimental colitis in mice and prevents endotoxin shock. The long isoform of TSLP is proinflammatory and is only expressed during inflammation. The isoforms are differentially regulated by pathogenic bacteria, such as Salmonella species and adhesive-invasive Escherichia coli. Conclusions We have solved the dilemma of TSLP being both homeostatic and inflammatory. The TSLP isoform ratio is altered during several inflammatory disorders, with strong implications in disease treatment and prevention. Indeed, targeting of the long isoform of TSLP at the C-terminal portion, which is common to both isoforms, might lead to unwanted side effects caused by neutralization of the homeostatic short isoform. PMID:26014813

  14. Computational Estimates of Binding Affinities for Estrogen Receptor Isoforms in Rainbow Trout

    CERN Document Server

    Shyu, Conrad

    2009-01-01

    Molecular dynamics simulations are performed to determine the binding affinities between the hormone 17 beta-estradiol (E2) and different estrogen receptor (ER) isoforms in the rainbow trout (Oncorhynchus mykiss). Previous studies have demonstrated that a recent, unique gene duplication of the ER alpha subtype created two isoforms ER alpha 1 and ER alpha 2, and an early secondary split of ER beta produced two distinct isoforms of ER beta 1 and ER beta 2 based on the phylogenetic analysis. The objective of our computational studies is to provide insight into the underlying evolutionary selection pressure on the ER isoforms. Our results show that E2 binds preferentially to ER alpha 1. This finding corresponds to the experimental results as the ERs evolved from gene duplication events are frequently free from selective pressure and should exhibit no deleterious effects. The E2, however, only binds slightly better to ER beta 2. Both isoforms remain competitive. This finding reflects the fact that since ER beta 2 ...

  15. Silencing GFAP isoforms in astrocytoma cells disturbs laminin-dependent motility and cell adhesion.

    Science.gov (United States)

    Moeton, Martina; Kanski, Regina; Stassen, Oscar M J A; Sluijs, Jacqueline A; Geerts, Dirk; van Tijn, Paula; Wiche, Gerhard; van Strien, Miriam E; Hol, Elly M

    2014-07-01

    Glial fibrillary acidic protein (GFAP) is an intermediate filament protein expressed in astrocytes and neural stem cells. The GFAP gene is alternatively spliced, and expression of GFAP is highly regulated during development, on brain damage, and in neurodegenerative diseases. GFAPα is the canonical splice variant and is expressed in all GFAP-positive cells. In the human brain, the alternatively spliced transcript GFAPδ marks specialized astrocyte populations, such as subpial astrocytes and the neurogenic astrocytes in the human subventricular zone. We here show that shifting the GFAP isoform ratio in favor of GFAPδ in astrocytoma cells, by selectively silencing the canonical isoform GFAPα with short hairpin RNAs, induced a change in integrins, a decrease in plectin, and an increase in expression of the extracellular matrix component laminin. Together, this did not affect cell proliferation but resulted in a significantly decreased motility of astrocytoma cells. In contrast, a down-regulation of all GFAP isoforms led to less cell spreading, increased integrin expression, and a >100-fold difference in the adhesion of astrocytoma cells to laminin. In summary, isoform-specific silencing of GFAP revealed distinct roles of a specialized GFAP network in regulating the interaction of astrocytoma cells with the extracellular matrix through laminin.-Moeton, M., Kanski, R., Stassen, O. M. J. A., Sluijs, J. A., Geerts, D., van Tijn, P., Wiche, G., van Strien, M. E., Hol, E. M. Silencing GFAP isoforms in astrocytoma cells disturbs laminin dependent motility and cell adhesion.

  16. iReckon: simultaneous isoform discovery and abundance estimation from RNA-seq data.

    Science.gov (United States)

    Mezlini, Aziz M; Smith, Eric J M; Fiume, Marc; Buske, Orion; Savich, Gleb L; Shah, Sohrab; Aparicio, Sam; Chiang, Derek Y; Goldenberg, Anna; Brudno, Michael

    2013-03-01

    High-throughput RNA sequencing (RNA-seq) promises to revolutionize our understanding of genes and their role in human disease by characterizing the RNA content of tissues and cells. The realization of this promise, however, is conditional on the development of effective computational methods for the identification and quantification of transcripts from incomplete and noisy data. In this article, we introduce iReckon, a method for simultaneous determination of the isoforms and estimation of their abundances. Our probabilistic approach incorporates multiple biological and technical phenomena, including novel isoforms, intron retention, unspliced pre-mRNA, PCR amplification biases, and multimapped reads. iReckon utilizes regularized expectation-maximization to accurately estimate the abundances of known and novel isoforms. Our results on simulated and real data demonstrate a superior ability to discover novel isoforms with a significantly reduced number of false-positive predictions, and our abundance accuracy prediction outmatches that of other state-of-the-art tools. Furthermore, we have applied iReckon to two cancer transcriptome data sets, a triple-negative breast cancer patient sample and the MCF7 breast cancer cell line, and show that iReckon is able to reconstruct the complex splicing changes that were not previously identified. QT-PCR validations of the isoforms detected in the MCF7 cell line confirmed all of iReckon's predictions and also showed strong agreement (r(2) = 0.94) with the predicted abundances. PMID:23204306

  17. Electrophoretic Mobility of Cardiac Myosin Heavy Chain Isoforms Revisited: Application of MALDI TOF/TOF Analysis

    Directory of Open Access Journals (Sweden)

    Petra Arnostova

    2011-01-01

    Full Text Available The expression of two cardiac myosin heavy chain (MyHC isoforms in response to the thyroid status was studied in left ventricles (LVs of Lewis rats. Major MyHC isoform in euthyroid and hyperthyroid LVs had a higher mobility on SDS-PAGE, whereas hypothyroid LVs predominantly contained a MyHC isoform with a lower mobility corresponding to that of the control soleus muscle. By comparing the MyHC profiles obtained under altered thyroid states together with the control soleus, we concluded that MyHCα was represented by the lower band with higher mobility and MyHCβ by the upper band. The identity of these two bands in SDS-PAGE gels was confirmed by western blot and mass spectrometry. Thus, in contrast to the literature data, we found that the MyHCα possessed a higher mobility rate than the MyHCβ isoform. Our data highlighted the importance of the careful identification of the MyHCα and MyHCβ isoforms analyzed by the SDS-PAGE.

  18. Quantitative profiling of Drosophila melanogaster Dscam1 isoforms reveals no changes in splicing after bacterial exposure.

    Directory of Open Access Journals (Sweden)

    Sophie A O Armitage

    Full Text Available The hypervariable Dscam1 (Down syndrome cell adhesion molecule 1 gene can produce thousands of different ectodomain isoforms via mutually exclusive alternative splicing. Dscam1 appears to be involved in the immune response of some insects and crustaceans. It has been proposed that the diverse isoforms may be involved in the recognition of, or the defence against, diverse parasite epitopes, although evidence to support this is sparse. A prediction that can be generated from this hypothesis is that the gene expression of specific exons and/or isoforms is influenced by exposure to an immune elicitor. To test this hypothesis, we for the first time, use a long read RNA sequencing method to directly investigate the Dscam1 splicing pattern after exposing adult Drosophila melanogaster and a S2 cell line to live Escherichia coli. After bacterial exposure both models showed increased expression of immune-related genes, indicating that the immune system had been activated. However there were no changes in total Dscam1 mRNA expression. RNA sequencing further showed that there were no significant changes in individual exon expression and no changes in isoform splicing patterns in response to bacterial exposure. Therefore our studies do not support a change of D. melanogaster Dscam1 isoform diversity in response to live E. coli. Nevertheless, in future this approach could be used to identify potentially immune-related Dscam1 splicing regulation in other host species or in response to other pathogens.

  19. Secretion of PDGF isoforms during osteoclastogenesis and its modulation by anti-osteoclast drugs.

    Science.gov (United States)

    Rahman, M Motiur; Matsuoka, Kazuhiko; Takeshita, Sunao; Ikeda, Kyoji

    2015-06-26

    In an attempt to identify secretory products of osteoclasts that mediate the coupling of bone formation to resorption, we found that along with osteoclast differentiation, PDGF-A gene expression increase occurred first, by 12 h after stimulation of bone marrow macrophages with M-CSF and RANKL, and peaked at 36 h. This was next followed by a progressive increase in PDGF-B gene expression until a peak at 60 h, when mature osteoclasts formed. Isoform-specific ELISA of the conditioned medium collected every 24 h revealed that all three of the isoforms of PDGF-AA, AB and BB were secreted, in this temporal order as differentiation proceeded. Their secretion was enhanced when osteoclasts were activated by placing them on dentin slices. The secretion of all three isoforms was decreased in cathepsin K-deficient osteoclasts compared with wild-type osteoclasts. Pharmacological inhibition of cathepsin K with odanacatib also inhibited the secretion of all three isoforms, as was also the case with alendronate treatment. The secretion of sphingosine-1-phosphate, which increased during osteoclastogenesis, was reduced from cathepsin K-deficient osteoclasts, and was inhibited by treatment with odanacatib more profoundly than with alendronate. Thus, all three isoforms of PDGF, which are secreted at distinct differentiation stages of osteoclasts, appear to have distinct roles in the cell-cell communication that takes place in the microenvironment of bone remodeling, especially from the osteoclast lineage to mesenchymal cells and vascular cells, thereby stimulating osteogenesis and angiogenesis. PMID:25951977

  20. Nesprin-2 epsilon: A novel nesprin isoform expressed in human ovary and Ntera-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Le Thanh [Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG (United Kingdom); Boehm, Sabrina V.; Roberts, Roland G. [Department of Medical and Molecular Genetics, King' s College London, London SE1 9RT (United Kingdom); Morris, Glenn E., E-mail: glennmanc@hotmail.com [Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG (United Kingdom); Institute of Science and Technology in Medicine, Keele University, Keele ST5 5BG (United Kingdom)

    2011-08-26

    Highlights: {yields} A novel epsilon isoform of nesprin-2 has been discovered. {yields} This 120 kDa protein was predicted by bioinformatic analysis, but has not previously been observed. {yields} It is the main isoform expressed in a teratocarcinoma cell line and is also found in ovary. {yields} Like other nesprins, it is located at the nuclear envelope. {yields} We suggest it may have a role in very early development or in some ovary-specific function. -- Abstract: The nuclear envelope-associated cytoskeletal protein, nesprin-2, is encoded by a large gene containing several internal promoters that produce shorter isoforms. In a study of Ntera-2 teratocarcinoma cells, a novel isoform, nesprin-2-epsilon, was found to be the major mRNA and protein product of the nesprin-2 gene. Its existence was predicted by bioinformatic analysis, but this is the first direct demonstration of both the mRNA and the 120 kDa protein which is located at the nuclear envelope. In a panel of 21 adult and foetal human tissues, the nesprin-2-epsilon mRNA was strongly expressed in ovary but was a minor isoform elsewhere. The expression pattern suggests a possible link with very early development and a likely physiological role in ovary.

  1. Alterations of Lymphoid Enhancer Factor-1 Isoform Expression in Solid Tumors and Acute Leukemias

    Institute of Scientific and Technical Information of China (English)

    Wenbing WANG; Carsten M(U)LLER-TIDOW; Ping JI; Bj(o)rn STEFFEN; Ralf METZGER; Paul M. SCHNEIDER; Hartmut HALFTER; Mark SCHRADER; Wolfgang E. BERDEL; Hubert SERVE

    2005-01-01

    Two major transcripts of lymphoid enhancer factor-1 (LEF-1) have been described. The long isoform with β-catenin binding domain functions as a transcriptional enhancer factor. The short isoform derives from an intronic promoter and exhibits dominant negative activity. Recently, alterations of LEF- 1isoforms distribution have been described in colon cancer. In the current study we employed a quantitative real-time reverse transcription PCR method (TaqMan) to analyze expression of LEF-1 isoforms in a large cohort of human tumor (n=304) and tumor-free control samples (n=56). The highest expression level of LEF-1 was found in carcinoma samples whereas brain cancer samples expressed little. Expression of LEF1 was different in distinct cancer types. For example, the mRNA level of LEF-1 was lower in testicular tumor samples compared with tumor-free control samples. Besides epithelial cancers, significant LEF-1expression was also found in hematopoietic cells. In hematological malignancies, overall LEF-1 level was higher in lymphocytic leukemias compared with myeloid leukemias and normal hematopoiesis. However,acute myeloid leukemia and acute lymphocytic leukemia showed a significantly increased fraction of the oncogenic LEF-1 compared with chronic lymphocytic leukemia and chronic myeloid leukemia. Taken together,these data suggest that LEF-1 is abundantly expressed in human tumors and the ratio of the oncogenic and the dominant negative short isoform altered not only in carcinomas but also in leukemia.

  2. Two isoforms of aquaporin 2 responsive to hypertonic stress in the bottlenose dolphin.

    Science.gov (United States)

    Suzuki, Miwa; Wakui, Hitomi; Itou, Takuya; Segawa, Takao; Inoshima, Yasuo; Maeda, Ken; Kikuchi, Kiyoshi

    2016-04-15

    This study investigated the expression of aquaporin 2 (AQP2) and its newly found alternatively spliced isoform (alternative AQP2) and the functions of these AQP2 isoforms in the cellular hyperosmotic tolerance in the bottlenose dolphin, ITALIC! Tursiops truncatus mRNA sequencing revealed that alternative AQP2 lacks the fourth exon and instead has a longer third exon that includes a part of the original third intron. The portion of the third intron, now part of the coding region of alternative AQP2, is highly conserved among many species of the order Cetacea but not among terrestrial mammals. Semi-quantitative PCR revealed that AQP2 was expressed only in the kidney, similar to terrestrial mammals. In contrast, alternative AQP2 was expressed in all organs examined, with strong expression in the kidney. In cultured renal cells, expression of both AQP2 isoforms was upregulated by the addition to the medium of NaCl but not by the addition of mannitol, indicating that the expression of both isoforms is induced by hypersalinity. Treatment with small interfering RNA for both isoforms resulted in a decrease in cell viability in hypertonic medium (500 mOsm kg(-1)) when compared with controls. These findings indicate that the expression of alternatively spliced AQP2 is ubiquitous in cetacean species, and it may be one of the molecules important for cellular osmotic tolerance throughout the body. PMID:26944501

  3. Regulation of three isoforms of SOD gene by environmental stresses in citrus red mite, Panonychus citri.

    Science.gov (United States)

    Feng, Ying-Cai; Liao, Chong-Yu; Xia, Wen-Kai; Jiang, Xuan-Zhao; Shang, Feng; Yuan, Guo-Rui; Wang, Jin-Jun

    2015-09-01

    Superoxide dismutase (SOD) is a family of enzymes with multiple isoforms that possess antioxidative abilities in response to environmental stresses. Panonychus citri is one of the most important pest mites and has a global distribution. In this study, three distinct isoforms of SOD were cloned from P. citri and identified as cytoplasmic Cu-ZnSOD (PcSOD1), extracellular Cu-ZnSOD (PcSOD2), and mitochondrial MnSOD (PcSOD3). mRNA expression level analysis showed that all three isoforms were up-regulated significantly after exposure to the acaricide abamectin and to UV-B ultraviolet irradiation. In particular, PcSOD3 was up-regulated under almost all environmental stresses tested. The fold change of PcSOD3 expression was significantly higher than those of the two Cu-ZnSOD isoforms. Taken together, the results indicate that abamectin and UV-B can induce transcripts of all three SOD isoforms in P. citri. Furthermore, PcSOD3 seems to play a more important role in P. citri tolerance to oxidative stress. PMID:26063404

  4. Serum amyloid A isoforms in serum and synovial fluid from spontaneously diseased dogs with joint diseases or other conditions

    DEFF Research Database (Denmark)

    Kjelgaard-Hansen, Mads Jens; Christensen, Michelle B.; Lee, Marcel Huisung;

    2007-01-01

    in samples obtained from dogs (n = 16) suffering from different inflammatory or non-inflammatory conditions, which were either related or unrelated to joints. Expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. Serum amyloid A was present in serum from all dogs...... with systemic inflammatory activity, and up to four major isoforms with apparent isoelectric points between 6.1 and 7.9 were identified. In synovial fluid from inflamed joints one or more highly alkaline SAA isoforms (with apparent isoelectric points above 9.3) were identified, with data suggesting local...... production of these isoforms in the canine inflamed joint....

  5. Aryl hydrocarbon receptor nuclear translocator (ARNT) isoforms control lymphoid cancer cell proliferation through differentially regulating tumor suppressor p53 activity.

    Science.gov (United States)

    Gardella, Kacie A; Muro, Israel; Fang, Gloria; Sarkar, Krishnakali; Mendez, Omayra; Wright, Casey W

    2016-03-01

    The aryl hydrocarbon receptor nuclear translocator (ARNT) is involved in xenobiotic and hypoxic responses, and we previously showed that ARNT also regulates nuclear factor-κB (NF-κB) signaling by altering the DNA binding activity of the RelB subunit. However, our initial study of ARNT-mediated RelB modulation was based on simultaneous suppression of the two ARNT isoforms, isoform 1 and 3, and precluded the examination of their individual functions. We find here that while normal lymphocytes harbor equal levels of isoform 1 and 3, lymphoid malignancies exhibit a shift to higher levels of ARNT isoform 1. These elevated levels of ARNT isoform 1 are critical to the proliferation of these cancerous cells, as suppression of isoform 1 in a human multiple myeloma (MM) cell line, and an anaplastic large cell lymphoma (ALCL) cell line, triggered S-phase cell cycle arrest, spontaneous apoptosis, and sensitized cells to doxorubicin treatment. Furthermore, co-suppression of RelB or p53 with ARNT isoform 1 prevented cell cycle arrest and blocked doxorubicin induced apoptosis. Together our findings reveal that certain blood cancers rely on ARNT isoform 1 to potentiate proliferation by antagonizing RelB and p53-dependent cell cycle arrest and apoptosis. Significantly, our results identify ARNT isoform 1 as a potential target for anticancer therapies.

  6. Glucocorticoid receptor translational isoforms underlie maturational stage-specific glucocorticoid sensitivities of dendritic cells in mice and humans

    OpenAIRE

    Cao, Yun; Bender, Ingrid K.; Konstantinidis, Athanasios K.; Shin, Soon Cheon; Jewell, Christine M.; Cidlowski, John A; Schleimer, Robert P.; Lu, Nick Z.

    2013-01-01

    Mature, but not immature, dendritic cells are sensitive to glucocorticoid-induced apoptosis.Mature, but not immature, dendritic cells express proapoptotic glucocorticoid receptor translational isoforms.

  7. Cysteine dioxygenase and cysteine sulfinate decarboxylase genes of the deep-sea mussel Bathymodiolus septemdierum: possible involvement in hypotaurine synthesis and adaptation to hydrogen sulfide.

    Science.gov (United States)

    Nagasaki, Toshihiro; Hongo, Yuki; Koito, Tomoko; Nakamura-Kusakabe, Ikumi; Shimamura, Shigeru; Takaki, Yoshihiro; Yoshida, Takao; Maruyama, Tadashi; Inoue, Koji

    2015-03-01

    It has been suggested that invertebrates inhabiting deep-sea hydrothermal vent areas use the sulfinic acid hypotaurine, a precursor of taurine, to protect against the toxicity of hydrogen sulfide contained in the seawater from the vent. In this protective system, hypotaurine is accumulated in the gill, the primary site of sulfide exposure. However, the pathway for hypotaurine synthesis in mollusks has not been identified. In this study, we screened for the mRNAs of enzymes involved in hypotaurine synthesis in the deep-sea mussel Bathymodiolus septemdierum and cloned cDNAs encoding cysteine dioxygenase and cysteine sulfinate decarboxylase. As mRNAs encoding cysteamine dioxygenase and cysteine lyase were not detected, the cysteine sulfinate pathway is suggested to be the major pathway of hypotaurine and taurine synthesis. The two genes were found to be expressed in all the tissues examined, but the gill exhibited the highest expression. The mRNA level in the gill was not significantly changed by exposure to sulfides or thiosulfate. These results suggests that the gill of B. septemdierum maintains high levels of expression of the two genes regardless of ambient sulfide level and accumulates hypotaurine continuously to protect against sudden exposure to high level of sulfide.

  8. Non-chemical proton-dependent steps prior to O2-activation limit Azotobacter vinelandii 3-mercaptopropionic acid dioxygenase (MDO) catalysis.

    Science.gov (United States)

    Crowell, Joshua K; Sardar, Sinjinee; Hossain, Mohammad S; Foss, Frank W; Pierce, Brad S

    2016-08-15

    3-mercaptopropionate dioxygenase from Azotobacter vinelandii (Av MDO) is a non-heme mononuclear iron enzyme that catalyzes the O2-dependent oxidation of 3-mercaptopropionate (3mpa) to produce 3-sulfinopropionic acid (3spa). With one exception, the active site residues of MDO are identical to bacterial cysteine dioxygenase (CDO). Specifically, the CDO Arg-residue (R50) is replaced by Gln (Q67) in MDO. Despite this minor active site perturbation, substrate-specificity of Av MDO is more relaxed as compared to CDO. In order to investigate the relative timing of chemical and non-chemical events in Av MDO catalysis, the pH/D-dependence of steady-state kinetic parameters (kcat and kcat/KM) and viscosity effects are measured using two different substrates [3mpa and l-cysteine (cys)]. The pL-dependent activity of Av MDO in these reactions can be rationalized assuming a diprotic enzyme model in which three ionic forms of the enzyme are present [cationic, E((z+1)); neutral, E(z); and anionic, E((z-1))]. The activities observed for each substrate appear to be dominated by electrostatic interactions within the enzymatic active site. Given the similarity between MDO and the more extensively characterized mammalian CDO, a tentative model for the role of the conserved 'catalytic triad' is proposed. PMID:27311613

  9. Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants

    International Nuclear Information System (INIS)

    Bacterial dioxygenases are useful in breakdown of PCB products associated with plants. - Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation

  10. Expression, purification, crystallization and preliminary X-ray analysis of a novel N-substituted branched-chain l-amino-acid dioxygenase from Burkholderia ambifaria AMMD

    International Nuclear Information System (INIS)

    Diffraction data were collected to a limiting resolution of 2.4 Å from a crystal of selenomethionyl-labelled SadA, an l-amino-acid dioxygenase. Ferrous ion- and α-ketoglutarate-dependent dioxygenase from Burkholderia ambifaria AMMD (SadA) catalyzes the C3-hydroxylation of N-substituted branched-chain l-amino acids, especially N-succinyl-l-leucine, coupled to the conversion of α-ketoglutarate to succinate and CO2. SadA was expressed in Escherichia coli, purified and crystallized using the sitting-drop vapour-diffusion method at 293 K. Crystals of selenomethionine-substituted SadA were obtained using a reservoir solution containing PEG 3000 as the precipitant at pH 9.5 and diffracted X-rays to 2.4 Å resolution. The crystal belonged to space group P212121, with unit-cell parameters a = 49.3, b = 70.9, c = 148.2 Å. The calculated Matthews coefficient (VM = 2.1 Å3 Da−1, 41% solvent content) suggested that the crystal contains two molecules per asymmetric unit

  11. Inhibition of para-Hydroxyphenylpyruvate Dioxygenase by Analogues of the Herbicide Nitisinone As a Strategy to Decrease Homogentisic Acid Levels, the Causative Agent of Alkaptonuria.

    Science.gov (United States)

    Laschi, Marcella; Bernardini, Giulia; Dreassi, Elena; Millucci, Lia; Geminiani, Michela; Braconi, Daniela; Marzocchi, Barbara; Botta, Maurizio; Manetti, Fabrizio; Santucci, Annalisa

    2016-04-01

    Alkaptonuria (AKU) is a rare multisystem metabolic disease caused by deficient activity of homogentisate 1,2-dioxygenase (HGD), which leads to the accumulation of homogentisic acid (HGA). Currently, there is no treatment for AKU. The sole drug with some beneficial effects is the herbicide nitisinone (1), an inhibitor of p-hydroxyphenylpyruvate dioxygenase (4-HPPD). 1 has been used as a life-saving drug in infants with type I tyrosinemia despite severe side effects due to the buildup of tyrosine. Four clinical trials of nitisinone to treat AKU have shown that 1 consistently decreases HGA levels, but also caused the accumulation of tyrosine in blood serum. Moreover, the human preclinical toxicological data for 1 are incomplete. In this work, we performed pharmacodynamics and toxicological evaluations of 1, providing the first report of LD50 values in human cells. Intracellular tyrosinemia was also evaluated. Three additional 4-HPPD inhibitors with a more favorable profile than that of 1 in terms of IC50 , LD50 , and tyrosine accumulation were also identified among commercially available compounds. These may be promising starting points for the development of new therapeutic strategies for the treatment of AKU. PMID:26947423

  12. Inhibition of para-Hydroxyphenylpyruvate Dioxygenase by Analogues of the Herbicide Nitisinone As a Strategy to Decrease Homogentisic Acid Levels, the Causative Agent of Alkaptonuria.

    Science.gov (United States)

    Laschi, Marcella; Bernardini, Giulia; Dreassi, Elena; Millucci, Lia; Geminiani, Michela; Braconi, Daniela; Marzocchi, Barbara; Botta, Maurizio; Manetti, Fabrizio; Santucci, Annalisa

    2016-04-01

    Alkaptonuria (AKU) is a rare multisystem metabolic disease caused by deficient activity of homogentisate 1,2-dioxygenase (HGD), which leads to the accumulation of homogentisic acid (HGA). Currently, there is no treatment for AKU. The sole drug with some beneficial effects is the herbicide nitisinone (1), an inhibitor of p-hydroxyphenylpyruvate dioxygenase (4-HPPD). 1 has been used as a life-saving drug in infants with type I tyrosinemia despite severe side effects due to the buildup of tyrosine. Four clinical trials of nitisinone to treat AKU have shown that 1 consistently decreases HGA levels, but also caused the accumulation of tyrosine in blood serum. Moreover, the human preclinical toxicological data for 1 are incomplete. In this work, we performed pharmacodynamics and toxicological evaluations of 1, providing the first report of LD50 values in human cells. Intracellular tyrosinemia was also evaluated. Three additional 4-HPPD inhibitors with a more favorable profile than that of 1 in terms of IC50, LD50, and tyrosine accumulation were also identified among commercially available compounds. These may be promising starting points for the development of new therapeutic strategies for the treatment of AKU.

  13. Spectroscopic and computational studies of NTBC bound to the non-heme iron enzyme (4-hydroxyphenyl)pyruvate dioxygenase: active site contributions to drug inhibition.

    Science.gov (United States)

    Neidig, Michael L; Decker, Andrea; Kavana, Michael; Moran, Graham R; Solomon, Edward I

    2005-12-01

    (4-Hydroxyphenyl)pyruvate dioxygenase (HPPD) is an alpha-keto-acid-dependent dioxygenase which catalyzes the conversion of (4-hydroxyphenyl)pyruvate (HPP) to homogentisate as part of tyrosine catabolism. While several di- and tri-ketone alkaloids are known as inhibitors of HPPD and used commercially as herbicides, one such inhibitor, [2-nitro-4-(trifluoromethyl)benzoyl]-1,3-cyclohexanedione (NTBC), has also been used therapeutically to treat type I tyrosinemia and alkaptonuria in humans. To gain further insight into the mechanism of inhibition by NTBC, a combination of CD/MCD spectroscopy and DFT calculations of HPPD/Fe(II)/NTBC has been performed to evaluate the contribution of the Fe(II)-NTBC bonding interaction to the high affinity of this drug for the enzyme. The results indicate that the bonding of NTBC to Fe(II) is very similar to that for HPP, both involving similar pi-backbonding interactions between NTBC/HPP and Fe(II). Combined with the result that the calculated binding energy of NTBC is, in fact, approximately 3 kcal/mol less than that for HPP, the bidentate coordination of NTBC to Fe(II) is not solely responsible for its extremely high affinity for the enzyme. Thus, the pi-stacking interactions between the aromatic rings of NTBC and two phenyalanine residues, as observed in the crystallography of the HPPD/Fe(II)/NTBC complex, appear to be responsible for the observed high affinity of drug binding.

  14. Preparation, crystallization and X-ray diffraction analysis to 1.5 Å resolution of rat cysteine dioxygenase, a mononuclear iron enzyme responsible for cysteine thiol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Chad R. [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States); Hao, Quan [MacCHESS at the Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853-8001 (United States); Stipanuk, Martha H., E-mail: mhs6@cornell.edu [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States)

    2005-11-01

    Recombinant rat cysteine dioxygenase (CDO) has been expressed, purified and crystallized and X-ray diffraction data have been collected to 1.5 Å resolution. Cysteine dioxygenase (CDO; EC 1.13.11.20) is an ∼23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O{sub 2}, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Å resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Å, α = β = γ = 90°. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  15. Purification of Biotransformation Products of Cis-Isoflavan-4-ol by Biphenyl Dioxygenase of Pseudomonas pseudoalcaligenes KF707 Strain Expressed in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Tri Ratna Sulistiyani

    2013-04-01

    Full Text Available Isoflavone has multiple beneficial effects on human health, especially through its antioxidant and anticancer activities. The biotransformation of isoflavone using byphenyl dioxygenase could be performed to extend the diversity of flavonoids and to improve their biological and physiological properties. Biotransformation of two enantiomers (3R, 4R-cis-isoflavan-4-ol and (3S, 4S-cis-isoflavan-4-ol by E. coli JM109 (pJHF108 carrying a biphenyl dioxygenase gene from P. pseudoalcaligenesKF707 produced two products, designated as CM1 andCM2. The products had a retention time of 11.9 and 14.6 min, respectively, and the same absorption peaks at 204, 220, and 275 nm. CM1 and CM2 had [M-H2O+H]+ at m/z 225. Based on the molecular mass and hydrolysis products, we proposed that epoxidation occurred on cis-isoflavan-4-ol. Chloroform extraction instead of ethyl acetate extraction was performed to improve the stability of cismetabolites, CM1 and CM2.

  16. Molecular Cloning and Characterization of a New Cold-active Extradiol Dioxygenase from a Metagenomic Library Derived from Polychlorinated Biphenyl-contaminated Soil

    Institute of Scientific and Technical Information of China (English)

    REN He-jun; LU Yang; ZHOU Rui; DAI Chun-yan; WANG Yan; ZHANG Lan-ying

    2012-01-01

    To find new extradiol dioxygenases(EDOs,EC 1.13.11.2),a metagenomics library was constructed from polychlorinated biphenyl-contaminated soil and was screened for some dioxygenase with aromatic ring cleavage activity.A novel EDO,designated as BphC_A,was identified and heterologously expressed in Escherichia coli.The deduced amino acid sequence of BphC_A exhibited a homology of less than 60% with other known EDOs.Phylogenetic analysis of BphC_A suggests that the protein is a novel member of the EDO family.The enzyme exhibits higher substrate affinity and catalytic efficiency toward 3-methylcatechol than toward 2,3-dihydroxybiphenyl or catechol,the preferred substrate of other known EDOs.The optimum activity of purified BphC_A occurred at pH=8.5 and 35 ℃,and BphC_A showed more than 40% of its initial activity at 5 ℃.The activity of purified BphC_A was significantly induced by Mn2+ and slightly reduced bv Al3+,Cu2+ and Zn2+.

  17. Functional identification of APIP as human mtnB, a key enzyme in the methionine salvage pathway.

    Directory of Open Access Journals (Sweden)

    Camille Mary

    Full Text Available The methionine salvage pathway is widely distributed among some eubacteria, yeast, plants and animals and recycles the sulfur-containing metabolite 5-methylthioadenosine (MTA to methionine. In eukaryotic cells, the methionine salvage pathway takes place in the cytosol and usually involves six enzymatic activities: MTA phosphorylase (MTAP, EC 2.4.2.28, 5'-methylthioribose-1-phosphate isomerase (mtnA, EC 5.3.1.23, 5'-methylthioribulose-1-phosphate dehydratase (mtnB, EC: 4.2.1.109, 2,3-dioxomethiopentane-1-phosphate enolase/phosphatase (mtnC, EC 3.1.3.77, aci-reductone dioxygenase (mtnD, EC 1.13.11.54 and 4-methylthio-2-oxo-butanoate (MTOB transaminase (EC 2.6.1.-. The aim of this study was to complete the available information on the methionine salvage pathway in human by identifying the enzyme responsible for the dehydratase step. Using a bioinformatics approach, we propose that a protein called APIP could perform this role. The involvement of this protein in the methionine salvage pathway was investigated directly in HeLa cells by transient and stable short hairpin RNA interference. We show that APIP depletion specifically impaired the capacity of cells to grow in media where methionine is replaced by MTA. Using a Shigella mutant auxotroph for methionine, we confirm that the knockdown of APIP specifically affects the recycling of methionine. We also show that mutation of three potential phosphorylation sites does not affect APIP activity whereas mutation of the potential zinc binding site completely abrogates it. Finally, we show that the N-terminal region of APIP that is missing in the short isoform is required for activity. Together, these results confirm the involvement of APIP in the methionine salvage pathway, which plays a key role in many biological functions like cancer, apoptosis, microbial proliferation and inflammation.

  18. Exposing the specific roles of the invariant chain isoforms in shaping the MHC class II peptidome

    Directory of Open Access Journals (Sweden)

    Jean-Simon eFortin

    2013-12-01

    Full Text Available The peptide repertoire (peptidome associated with MHC class II molecules (MHCIIs is influenced by the polymorphic nature of the peptide binding groove but also by cell-intrinsic factors. The invariant chain (Ii chaperones MHCIIs, affecting their folding and trafficking. Recent discoveries relating to Ii functions have provided insights as to how it edits the MHCII peptidome. In humans, the Ii gene encodes four different isoforms for which structure-function analyses have highlighted common properties but also some non-redundant roles. Another layer of complexity arises from the fact that Ii heterotrimerizes, a characteristic that has the potential to affect the maturation of associated MHCIIs in many different ways, depending on the isoform combinations. Here, we emphasize the peptide editing properties of Ii and discuss the impact of the various isoforms on the MHCII peptidome.

  19. Epidermal growth-factor-induced transcript isoform variation drives mammary cell migration.

    Directory of Open Access Journals (Sweden)

    Wolfgang J Köstler

    Full Text Available Signal-induced transcript isoform variation (TIV includes alternative promoter usage as well as alternative splicing and alternative polyadenylation of mRNA. To assess the phenotypic relevance of signal-induced TIV, we employed exon arrays and breast epithelial cells, which migrate in response to the epidermal growth factor (EGF. We show that EGF rapidly--within one hour--induces widespread TIV in a significant fraction of the transcriptome. Importantly, TIV characterizes many genes that display no differential expression upon stimulus. In addition, similar EGF-dependent changes are shared by a panel of mammary cell lines. A functional screen, which utilized isoform-specific siRNA oligonucleotides, indicated that several isoforms play essential, non-redundant roles in EGF-induced mammary cell migration. Taken together, our findings highlight the importance of TIV in the rapid evolvement of a phenotypic response to extracellular signals.

  20. Alternative RNA splicing of KSHV ORF57 produces two different RNA isoforms.

    Science.gov (United States)

    Majerciak, Vladimir; Zheng, Zhi-Ming

    2016-01-15

    In lytically infected B cells Kaposi sarcoma-associated herpesvirus (KSHV) ORF57 gene encodes two RNA isoforms by alternative splicing of its pre-mRNA, which contains a small, constitutive intron in its 5' half and a large, suboptimal intron in its 3's half. The RNA1 isoform encodes full-length ORF57 and is a major isoform derived from splicing of the constitutive small intron, but retaining the suboptimal large intron as the coding region. A small fraction (splicing to produce a smaller non-coding RNA2 due to lack of a translational termination codon. Both RNAs are cleaved and polyadenylated at the same cleavage site CS83636. The insertion of ORF57 RNA1 into a restriction cutting site in certain mammalian expression vectors activates splicing of the subopitmal intron and produces a truncated ORF57 protein.

  1. Structural and Functional Characterization of Recombinant Isoforms of the Lentil Lipid Transfer Protein.

    Science.gov (United States)

    Bogdanov, I V; Finkina, E I; Balandin, S V; Melnikova, D N; Stukacheva, E A; Ovchinnikova, T V

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major peach allergen Pru p 3. Both isoforms were shown to have immunological properties similar to those of other plant allergenic LTPs, but Lc-LTP3 displayed a less pronounced immunoreactivity. PMID:26483961

  2. Altered Alpha-Synuclein, Parkin, and Synphilin Isoform Levels in Multiple System Atrophy Brains

    DEFF Research Database (Denmark)

    Brudek, Tomasz; Winge, Kristian; Bredo Rasmussen, Nadja;

    2016-01-01

    Together with Parkinson's disease (PD) and dementia with Lewy bodies (DLB), Multiple System Atrophy (MSA) is a member of a diverse group of neurodegenerative disorders termed α-synucleinopathies. Previously, it has been shown that alpha-synuclein, parkin and synphilin-1 display disease specific...... controls using isoform-specific primers and exon specific antibodies in substantia nigra, striatum, cerebellar cortex, and nucleus dentatus. These regions are severely affected by alpha-synuclein pathology and neurodegeneration. Further, we have also investigated transcript levels for parkin and synphilin...... increased levels of parkin isoforms lacking the N-terminal ubiquitin-like domain and an aggregation-prone synphiln-1A isoform that causes neuronal toxicity in MSA. In PD brains, Parkin transcript variant 3, 7 and 11 were significantly and specifically overexpressed in the striatum and cerebellar cortex...

  3. The respiratory chain supercomplex organization is independent of COX7a2l isoforms.

    Science.gov (United States)

    Mourier, Arnaud; Matic, Stanka; Ruzzenente, Benedetta; Larsson, Nils-Göran; Milenkovic, Dusanka

    2014-12-01

    The organization of individual respiratory chain complexes into supercomplexes or respirasomes has attracted great interest because of the implications for cellular energy conversion. Recently, it was reported that commonly used mouse strains harbor a short COX7a2l (SCAFI) gene isoform that supposedly precludes the formation of complex IV-containing supercomplexes. This claim potentially has serious implications for numerous mouse studies addressing important topics in metabolism, including adaptation to space flights. Using several complementary experimental approaches, we show that mice with the short COX7a2l isoform have normal biogenesis and steady-state levels of complex IV-containing supercomplexes and consequently have normal respiratory chain function. Furthermore, we use a mouse knockout of Lrpprc and show that loss of complex IV compromises respirasome formation. We conclude that the presence of the short COX7a2l isoform in the commonly used C57BL/6 mouse strains does not prevent their use in metabolism research.

  4. Protein interaction network of alternatively spliced isoforms from brain links genetic risk factors for autism.

    Science.gov (United States)

    Corominas, Roser; Yang, Xinping; Lin, Guan Ning; Kang, Shuli; Shen, Yun; Ghamsari, Lila; Broly, Martin; Rodriguez, Maria; Tam, Stanley; Trigg, Shelly A; Fan, Changyu; Yi, Song; Tasan, Murat; Lemmens, Irma; Kuang, Xingyan; Zhao, Nan; Malhotra, Dheeraj; Michaelson, Jacob J; Vacic, Vladimir; Calderwood, Michael A; Roth, Frederick P; Tavernier, Jan; Horvath, Steve; Salehi-Ashtiani, Kourosh; Korkin, Dmitry; Sebat, Jonathan; Hill, David E; Hao, Tong; Vidal, Marc; Iakoucheva, Lilia M

    2014-04-11

    Increased risk for autism spectrum disorders (ASD) is attributed to hundreds of genetic loci. The convergence of ASD variants have been investigated using various approaches, including protein interactions extracted from the published literature. However, these datasets are frequently incomplete, carry biases and are limited to interactions of a single splicing isoform, which may not be expressed in the disease-relevant tissue. Here we introduce a new interactome mapping approach by experimentally identifying interactions between brain-expressed alternatively spliced variants of ASD risk factors. The Autism Spliceform Interaction Network reveals that almost half of the detected interactions and about 30% of the newly identified interacting partners represent contribution from splicing variants, emphasizing the importance of isoform networks. Isoform interactions greatly contribute to establishing direct physical connections between proteins from the de novo autism CNVs. Our findings demonstrate the critical role of spliceform networks for translating genetic knowledge into a better understanding of human diseases.

  5. Staphylococcus aureus CstB is a novel multidomain persulfide dioxygenase-sulfurtransferase involved in hydrogen sulfide detoxification

    Science.gov (United States)

    Shen, Jiangchuan; Keithly, Mary E.; Armstrong, Richard N.; Higgins, Khadine A.; Edmonds, Katherine A.; Giedroc, David P.

    2016-01-01

    Hydrogen sulfide (H2S) is both a lethal gas and an emerging gasotransmitter in humans, suggesting that cellular H2S level must be tightly regulated. CstB is encoded by the cst operon of the major human pathogen Staphylococcus aureus (S. aureus) and is under the transcriptional control of the persulfide sensor CstR and H2S. Here we show that CstB is a multifunctional Fe(II)-containing persulfide dioxygenase (PDO), analogous to the vertebrate protein ETHE1 (Ethylmalonic Encephalopathy Protein 1). Chromosomal deletion of ethe1 is fatal in vertebrates. In the presence of molecular oxygen (O2), hETHE1 oxidizes glutathione persulfide (GSSH) to generate sulfite and reduced glutathione. In contrast, CstB oxidizes major cellular low molecular weight (LMW) persulfide substrates from S. aureus, coenzyme A persulfide (CoASSH) and bacillithiol persulfide (BSSH), directly to generate thiosulfate (TS) and reduced thiols, thereby avoiding the cellular toxicity of sulfite. Both Cys201 in the N-terminal PDO domain (CstBPDO) and Cys408 in the C-terminal rhodanese domain (CstBRhod) strongly enhance the TS generating activity of CstB. CstB also possesses persulfide transferase (PT; reverse rhodanese) activity which generates TS when provided with LMW persulfides and sulfite, as well as conventional thiosulfate transferase (TST; rhodanese) activity; both activities require Cys408. CstB protects S. aureus against H2S toxicity with C201S and C408S cstB genes unable to rescue a NaHS-induced ΔcstB growth phenotype. Induction of the cst operon by NaHS reveals that functional CstB impacts the cellular TS concentrations. These data collectively suggest that CstB may have evolved to facilitate the clearance of LMW persulfides that occur upon the elevation of the level of cellular H2S and hence may have an impact on bacterial viability under H2S stress, in concert with the other enzymes encoded by the cst operon. PMID:26177047

  6. Unraveling complex interplay between heat shock factor 1 and 2 splicing isoforms.

    Directory of Open Access Journals (Sweden)

    Sylvain Lecomte

    Full Text Available Chaperone synthesis in response to proteotoxic stress is dependent on a family of transcription factors named heat shock factors (HSFs. The two main factors in this family, HSF1 and HSF2, are co-expressed in numerous tissues where they can interact and form heterotrimers in response to proteasome inhibition. HSF1 and HSF2 exhibit two alternative splicing isoforms, called α and β, which contribute to additional complexity in HSF transcriptional regulation, but remain poorly examined in the literature. In this work, we studied the transcriptional activity of HSF1 and HSF2 splicing isoforms transfected into immortalized Mouse Embryonic Fibroblasts (iMEFs deleted for both Hsf1 and Hsf2, under normal conditions and after proteasome inhibition. We found that HSF1α is significantly more active than the β isoform after exposure to the proteasome inhibitor MG132. Furthermore, we clearly established that, while HSF2 had no transcriptional activity by itself, short β isoform of HSF2 exerts a negative role on HSF1β-dependent transactivation. To further assess the impact of HSF2β inhibition on HSF1 activity, we developed a mathematical modelling approach which revealed that the balance between each HSF isoform in the cell regulated the strength of the transcriptional response. Moreover, we found that cellular stress such as proteasome inhibition could regulate the splicing of Hsf2 mRNA. All together, our results suggest that relative amounts of each HSF1 and HSF2 isoforms quantitatively determine the cellular level of the proteotoxic stress response.

  7. Glutamic acid decarboxylase isoform distribution in transgenic mouse septum: an anti-GFP immunofluorescence study.

    Science.gov (United States)

    Verimli, Ural; Sehirli, Umit S

    2016-09-01

    The septum is a basal forebrain region located between the lateral ventricles in rodents. It consists of lateral and medial divisions. Medial septal projections regulate hippocampal theta rhythm whereas lateral septal projections are involved in processes such as affective functions, memory formation, and behavioral responses. Gamma-aminobutyric acidergic neurons of the septal region possess the 65 and 67 isoforms of the enzyme glutamic acid decarboxylase. Although data on the glutamic acid decarboxylase isoform distribution in the septal region generally appears to indicate glutamic acid decarboxylase 67 dominance, different studies have given inconsistent results in this regard. The aim of this study was therefore to obtain information on the distributions of both of these glutamic acid decarboxylase isoforms in the septal region in transgenic mice. Two animal groups of glutamic acid decarboxylase-green fluorescent protein knock-in transgenic mice were utilized in the experiment. Brain sections from the region were taken for anti-green fluorescent protein immunohistochemistry in order to obtain estimated quantitative data on the number of gamma-aminobutyric acidergic neurons. Following the immunohistochemical procedures, the mean numbers of labeled cells in the lateral and medial septal nuclei were obtained for the two isoform groups. Statistical analysis yielded significant results which indicated that the 65 isoform of glutamic acid decarboxylase predominates in both lateral and medial septal nuclei (unpaired two-tailed t-test p first to reveal the dominance of glutamic acid decarboxylase isoform 65 in the septal region in glutamic acid decarboxylase-green fluorescent protein transgenic mice. PMID:26643381

  8. The α and Δ isoforms of CREB1 are required to maintain normal pulmonary vascular resistance.

    Directory of Open Access Journals (Sweden)

    Lili Li

    Full Text Available Chronic hypoxia causes pulmonary hypertension associated with structural alterations in pulmonary vessels and sustained vasoconstriction. The transcriptional mechanisms responsible for these distinctive changes are unclear. We have previously reported that CREB1 is activated in the lung in response to alveolar hypoxia but not in other organs. To directly investigate the role of α and Δ isoforms of CREB1 in the regulation of pulmonary vascular resistance we examined the responses of mice in which these isoforms of CREB1 had been inactivated by gene mutation, leaving only the β isoform intact (CREB(αΔ mice. Here we report that expression of CREB regulated genes was altered in the lungs of CREB(αΔ mice. CREB(αΔ mice had greater pulmonary vascular resistance than wild types, both basally in normoxia and following exposure to hypoxic conditions for three weeks. There was no difference in rho kinase mediated vasoconstriction between CREB(αΔ and wild type mice. Stereological analysis of pulmonary vascular structure showed characteristic wall thickening and lumen reduction in hypoxic wild-type mice, with similar changes observed in CREB(αΔ. CREB(αΔ mice had larger lungs with reduced epithelial surface density suggesting increased pulmonary compliance. These findings show that α and Δ isoforms of CREB1 regulate homeostatic gene expression in the lung and that normal activity of these isoforms is essential to maintain low pulmonary vascular resistance in both normoxic and hypoxic conditions and to maintain the normal alveolar structure. Interventions that enhance the actions of α and Δ isoforms of CREB1 warrant further investigation in hypoxic lung diseases.

  9. Different characteristics and nucleotide binding properties of inosine monophosphate dehydrogenase (IMPDH isoforms.

    Directory of Open Access Journals (Sweden)

    Elaine C Thomas

    Full Text Available We recently reported that Inosine Monophosphate Dehydrogenase (IMPDH, a rate-limiting enzyme in de novo guanine nucleotide biosynthesis, clustered into macrostructures in response to decreased nucleotide levels and that there were differences between the IMPDH isoforms, IMPDH1 and IMPDH2. We hypothesised that the Bateman domains, which are present in both isoforms and serve as energy-sensing/allosteric modules in unrelated proteins, would contribute to isoform-specific differences and that mutations situated in and around this domain in IMPDH1 which give rise to retinitis pigmentosa (RP would compromise regulation. We employed immuno-electron microscopy to investigate the ultrastructure of IMPDH macrostructures and live-cell imaging to follow clustering of an IMPDH2-GFP chimera in real-time. Using a series of IMPDH1/IMPDH2 chimera we demonstrated that the propensity to cluster was conferred by the N-terminal 244 amino acids, which includes the Bateman domain. A protease protection assay suggested isoform-specific purine nucleotide binding characteristics, with ATP protecting IMPDH1 and AMP protecting IMPDH2, via a mechanism involving conformational changes upon nucleotide binding to the Bateman domain without affecting IMPDH catalytic activity. ATP binding to IMPDH1 was confirmed in a nucleotide binding assay. The RP-causing mutation, R224P, abolished ATP binding and nucleotide protection and this correlated with an altered propensity to cluster. Collectively these data demonstrate that (i the isoforms are differentially regulated by AMP and ATP by a mechanism involving the Bateman domain, (ii communication occurs between the Bateman and catalytic domains and (iii the RP-causing mutations compromise such regulation. These findings support the idea that the IMPDH isoforms are subject to distinct regulation and that regulatory defects contribute to human disease.

  10. In vivo human apolipoprotein E isoform fractional turnover rates in the CNS.

    Directory of Open Access Journals (Sweden)

    Kristin R Wildsmith

    Full Text Available Apolipoprotein E (ApoE is the strongest genetic risk factor for Alzheimer's disease and has been implicated in the risk for other neurological disorders. The three common ApoE isoforms (ApoE2, E3, and E4 each differ by a single amino acid, with ApoE4 increasing and ApoE2 decreasing the risk of Alzheimer's disease (AD. Both the isoform and amount of ApoE in the brain modulate AD pathology by altering the extent of amyloid beta (Aβ peptide deposition. Therefore, quantifying ApoE isoform production and clearance rates may advance our understanding of the role of ApoE in health and disease. To measure the kinetics of ApoE in the central nervous system (CNS, we applied in vivo stable isotope labeling to quantify the fractional turnover rates of ApoE isoforms in 18 cognitively-normal adults and in ApoE3 and ApoE4 targeted-replacement mice. No isoform-specific differences in CNS ApoE3 and ApoE4 turnover rates were observed when measured in human CSF or mouse brain. However, CNS and peripheral ApoE isoform turnover rates differed substantially, which is consistent with previous reports and suggests that the pathways responsible for ApoE metabolism are different in the CNS and the periphery. We also demonstrate a slower turnover rate for CSF ApoE than that for amyloid beta, another molecule critically important in AD pathogenesis.

  11. Mesenchymal Stromal Cells for Sphincter Regeneration: Role of Laminin Isoforms upon Myogenic Differentiation.

    Directory of Open Access Journals (Sweden)

    Tanja Seeger

    Full Text Available Multipotent mesenchymal stromal cells (MSCs are well known for their tri-lineage potential and ability to differentiate in vitro into osteogenic, chondrogenic or adipogenic lineages. By selecting appropriate conditions MSCs can also be differentiated in vitro into the myogenic lineage and are therefore a promising option for cell-based regeneration of muscle tissue such as an aged or damaged sphincter muscle. For the differentiation into the myogenic lineage there is still a need to evaluate the effects of extracellular matrix proteins such as laminins (LM which are crucial for different stem cell types and for normal muscle function. The laminin family consists of 16 functionally different isoforms with LM-211 being the most abundant isoform of adult muscle tissues. In the sphincter tissue a strong expression of the isoforms LM-211/221, LM-411/421 and LM-511/521 can be detected in the different cell layers. Bone marrow-derived MSCs in culture, however, mainly express the isoforms LM-411 and LM-511, but not LM-211. Even after myogenic differentiation, LM-211 can hardly be detected. All laminin isoforms tested (LM-211, LM-411, LM-511 and LM-521 showed a significant inhibition of the proliferation of undifferentiated MSCs but, with the exception of LM-521, they had no influence on the proliferation of MSCs cultivated in myogenic medium. The strongest cellular adhesion of MSCs was to LM-511 and LM-521, whereas LM-211 was only a weakly-adhesive substrate for MSCs. Myogenic differentiation of MSCs even reduced the interaction with LM-211, but it did not affect the interaction with LM-511 and LM-521. Since during normal myogenesis the latter two isoforms are the major laminins surrounding developing myogenic progenitors, α5 chain-containing laminins are recommended for further improvements of myogenic differentiation protocols of MSCs into smooth muscle cells.

  12. Crystal structures of a halophilic archaeal malate synthase from Haloferax volcanii and comparisons with isoforms A and G

    Directory of Open Access Journals (Sweden)

    Thomas Geoffrey C

    2011-05-01

    Full Text Available Abstract Background Malate synthase, one of the two enzymes unique to the glyoxylate cycle, is found in all three domains of life, and is crucial to the utilization of two-carbon compounds for net biosynthetic pathways such as gluconeogenesis. In addition to the main isoforms A and G, so named because of their differential expression in E. coli grown on either acetate or glycolate respectively, a third distinct isoform has been identified. These three isoforms differ considerably in size and sequence conservation. The A isoform (MSA comprises ~530 residues, the G isoform (MSG is ~730 residues, and this third isoform (MSH-halophilic is ~430 residues in length. Both isoforms A and G have been structurally characterized in detail, but no structures have been reported for the H isoform which has been found thus far only in members of the halophilic Archaea. Results We have solved the structure of a malate synthase H (MSH isoform member from Haloferax volcanii in complex with glyoxylate at 2.51 Å resolution, and also as a ternary complex with acetyl-coenzyme A and pyruvate at 1.95 Å. Like the A and G isoforms, MSH is based on a β8/α8 (TIM barrel. Unlike previously solved malate synthase structures which are all monomeric, this enzyme is found in the native state as a trimer/hexamer equilibrium. Compared to isoforms A and G, MSH displays deletion of an N-terminal domain and a smaller deletion at the C-terminus. The MSH active site is closely superimposable with those of MSA and MSG, with the ternary complex indicating a nucleophilic attack on pyruvate by the enolate intermediate of acetyl-coenzyme A. Conclusions The reported structures of MSH from Haloferax volcanii allow a detailed analysis and comparison with previously solved structures of isoforms A and G. These structural comparisons provide insight into evolutionary relationships among these isoforms, and also indicate that despite the size and sequence variation, and the truncated C

  13. Involvement of specific calmodulin isoforms in salicylic acid-independent activation of plant disease resistance responses

    OpenAIRE

    Heo, Won Do; Lee, Sang Hyoung; Kim, Min Chul; Kim, Jong Cheol; Chung, Woo Sik; Chun, Hyun Jin; Lee, Kyoung Joo; Park, Chan Young; Park, Hyeong Cheol; Choi, Ji Young; Cho, Moo Je

    1999-01-01

    The Ca2+ signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. Here we demonstrate that specific calmodulin (CaM) isoforms are activated by infection or pathogen-derived elicitors and participate in Ca2+-mediated induction of plant disease resistance responses. Soybean CaM (SCaM)-4 and SCaM-5 genes, which encode for divergent CaM isoforms, were induced within 30 min by a fungal elicitor or pathogen, wher...

  14. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    OpenAIRE

    Howarth, Deanna L.; Hagey, Lee R.; Law, Sheran H.W.; Ai, Ni; Krasowski, Matthew D.; Ekins, Sean; Moore, John T.; Erin M Kollitz; Hinton, David E.; Kullman, Seth W.

    2010-01-01

    The nuclear receptor farnesoid X receptor alpha (FXRα, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxrα in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXRα (~70% in the ligand-binding domain). Fxrα1 and Fxrα2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process...

  15. Progesterone receptor isoform A may regulate the effects of neoadjuvant aglepristone in canine mammary carcinoma

    DEFF Research Database (Denmark)

    Guil-Luna, Silvia; Stenvang, Jan; Brünner, Nils;

    2014-01-01

    and mRNA expression of progesterone receptor isoforms A and B in mammary carcinomas in dogs treated with 20 mg/Kg of aglepristone (n¿=¿22) or vehicle (n¿=¿5) twice before surgery.ResultsFormalin-fixed, paraffin-embedded tissue samples taken before and after treatment were used to analyse total......BackgroundProgesterone receptors play a key role in the development of canine mammary tumours, and recent research has focussed on their possible value as therapeutic targets using antiprogestins. Cloning and sequencing of the progesterone receptor gene has shown that the receptor has two isoforms...

  16. Each Individual Isoform of the Dopamine D2 Receptor Protects from Lactotroph Hyperplasia

    OpenAIRE

    Radl, Daniela; De Mei, Claudia; Chen, Eric; Lee, Hyuna; Borrelli, Emiliana

    2013-01-01

    Dopamine acting through D2 receptors (D2Rs) controls lactotroph proliferation and prolactin (PRL) levels. Ablation of this receptor in mice results in lactotroph hyperplasia and prolactinomas in aged females. Alternative splicing of the Drd2 gene generates 2 independent isoforms, a long (D2L) and a short (D2S) isoform, which are present in all D2R-expressing cells. Here, we addressed the role of D2L and D2S on lactotroph physiology through the generation and analysis of D2S-null mice and thei...

  17. Role of Sec24 isoforms in selective export of membrane proteins from the endoplasmic reticulum

    OpenAIRE

    Wendeler, Markus W; Paccaud, Jean-Pierre; Hauri, Hans-Peter

    2007-01-01

    Sec24 of the COPII (coat protein complex II) vesicle coat mediates the selective export of membrane proteins from the endoplasmic reticulum (ER) in yeast. Human cells express four Sec24 isoforms, but their role is unknown. Here, we report the differential effects of Sec24 isoform-specific silencing on the transport of the membrane reporter protein ERGIC-53 (ER–Golgi intermediate compartment-53) carrying the cytosolic ER export signals di-phenylalanine, di-tyrosine, di-leucine, di-isoleucine, ...

  18. Alternative Splicing Regulates the Subcellular Localization of Divalent Metal Transporter 1 Isoforms

    OpenAIRE

    Tabuchi, Mitsuaki; Tanaka, Naotaka; Nishida-Kitayama, Junko; Ohno, Hiroshi; Kishi, Fumio

    2002-01-01

    Divalent metal transporter 1 (DMT1) is responsible for dietary-iron absorption from apical plasma membrane in the duodenum and iron acquisition from the transferrin cycle endosomes in peripheral tissues. Two isoforms of the DMT1 transcript generated by alternative splicing of the 3′ exons have been identified in mouse, rat, and human. These isoforms can be distinguished by the different C-terminal amino acid sequences and by the presence (DMT1A) or absence (DMT1B) of an iron response element ...

  19. Distribution of protein kinase Mzeta and the complete protein kinase C isoform family in rat brain

    DEFF Research Database (Denmark)

    Naik, M U; Benedikz, Eirikur; Hernandez, I;

    2000-01-01

    Protein kinase C (PKC) is a multigene family of at least ten isoforms, nine of which are expressed in brain (alpha, betaI, betaII, gamma, delta, straightepsilon, eta, zeta, iota/lambda). Our previous studies have shown that many of these PKCs participate in synaptic plasticity in the CA1 region of......, protein kinase Mzeta (PKMzeta). In this study, we used immunoblot and immunocytochemical techniques with isoform-specific antisera to examine the distribution of the complete family of PKC isozymes and PKMzeta in rat brain. Each form of PKC showed a widespread distribution in the brain with a distinct...

  20. Structural and Functional Characterization of Recombinant Isoforms of the Lentil Lipid Transfer Protein

    OpenAIRE

    Bogdanov, I. V.; Finkina, E. I.; Balandin, S. V.; Melnikova, D. N.; Stukacheva, E. A.; Ovchinnikova, T. V.

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major ...

  1. STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF RECOMBINANT ISOFORMS OF THE LENTIL LIPID TRANSFER PROTEIN

    OpenAIRE

    Bogdanov, I. V.; Finkina, E. I.; Balandin, S. V.; Melnikova, D. N.; Stukacheva, E. A.; Ovchinnikova, T. V.

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major ...

  2. Lipoprotein(a) concentrations, isoform size, and risk of type 2 diabetes

    DEFF Research Database (Denmark)

    Kamstrup, Pia Rørbæk; Nordestgaard, Børge

    2013-01-01

    study to investigate whether large isoform size, low concentrations in plasma, or both, are causally associated with type 2 diabetes. METHODS: We assessed data for adults from the Danish general population enrolled in the Copenhagen City Heart Study and the Copenhagen General Population Study, with and......(a) concentrations alone seem not to be causally associated with type 2 diabetes, but a causal association for large lipoprotein(a) isoform size cannot be excluded. FUNDING: Danish Heart Foundation, Danish Council for Independent Research-Medical Sciences, IMK Almene Fund, and Johan and Lise Boserup's Fund....

  3. Lipoprotein(a) levels, isoform size, and risk of type 2 diabetes: A Mendelian randomisation study

    DEFF Research Database (Denmark)

    Kamstrup, Pia Rørbæk; Nordestgaard, Børge G.

    2013-01-01

    study to investigate whether large isoform size, low concentrations in plasma, or both, are causally associated with type 2 diabetes. Methods: We assessed data for adults from the Danish general population enrolled in the Copenhagen City Heart Study and the Copenhagen General Population Study, with and......(a) concentrations alone seem not to be causally associated with type 2 diabetes, but a causal association for large lipoprotein(a) isoform size cannot be excluded. Funding: Danish Heart Foundation, Danish Council for Independent Research-Medical Sciences, IMK Almene Fund, and Johan and Lise Boserup's Fund....

  4. VEGF121b and VEGF165b are weakly angiogenic isoforms of VEGF-A

    Directory of Open Access Journals (Sweden)

    Pio Ruben

    2010-12-01

    Full Text Available Abstract Background Different isoforms of VEGF-A (mainly VEGF121, VEGF165 and VEGF189 have been shown to display particular angiogenic properties in the generation of a functional tumor vasculature. Recently, a novel class of VEGF-A isoforms, designated as VEGFxxxb, generated through alternative splicing, have been described. Previous studies have suggested that these isoforms may inhibit angiogenesis. In the present work we have produced recombinant VEGF121/165b proteins in the yeast Pichia pastoris and constructed vectors to overexpress these isoforms and assess their angiogenic potential. Results Recombinant VEGF121/165b proteins generated either in yeasts or mammalian cells activated VEGFR2 and its downstream effector ERK1/2, although to a lesser extent than VEGF165. Furthermore, treatment of endothelial cells with VEGF121/165b increased cell proliferation compared to untreated cells, although such stimulation was lower than that induced by VEGF165. Moreover, in vivo angiogenesis assays confirmed angiogenesis stimulation by VEGF121/165b isoforms. A549 and PC-3 cells overexpressing VEGF121b or VEGF165b (or carrying the PCDNA3.1 empty vector, as control and xenotransplanted into nude mice showed increased tumor volume and angiogenesis compared to controls. To assess whether the VEGFxxxb isoforms are differentially expressed in tumors compared to healthy tissues, immunohistochemical analysis was conducted on a breast cancer tissue microarray. A significant increase (p xxxb and total VEGF-A protein expression in infiltrating ductal carcinomas compared to normal breasts was observed. A positive significant correlation (r = 0.404, p = 0.033 between VEGFxxxb and total VEGF-A was found. Conclusions Our results demonstrate that VEGF121/165b are not anti-angiogenic, but weakly angiogenic isoforms of VEGF-A. In addition, VEGFxxxb isoforms are up-regulated in breast cancer in comparison with non malignant breast tissues. These results are to be taken

  5. Characterization of PR-10 genes from eight Betula species and detection of Bet v 1 isoforms in birch pollen

    Directory of Open Access Journals (Sweden)

    van't Westende Wendy PC

    2009-03-01

    Full Text Available Abstract Background Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch (Betula pendula have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the genome was established by amplification and sequencing of alleles from eight birch species that represent the four subgenera within the genus Betula. Q-TOF LC-MSE was applied to identify which PR-10/Bet v 1 genes are actually expressed in pollen and to determine the relative abundances of individual isoforms in the pollen proteome. Results All examined birch species contained several PR-10 genes. In total, 134 unique sequences were recovered. Sequences were attributed to different genes or pseudogenes that were, in turn, ordered into seven subfamilies. Five subfamilies were common to all birch species. Genes of two subfamilies were expressed in pollen, while each birch species expressed a mixture of isoforms with at least four different isoforms. Isoforms that were similar to isoforms with a high IgE-reactivity (Bet v 1a = PR-10.01A01 were abundant in all species except B. lenta, while the hypoallergenic isoform Bet v 1d (= PR-10.01B01 was only found in B. pendula and its closest relatives. Conclusion Q-TOF LC-MSE allows efficient screening of Bet v 1 isoforms by determining the presence and relative abundance of these isoforms in pollen. B. pendula contains a Bet v 1-mixture in which isoforms with a high and low IgE-reactivity are both abundant. With the possible exception of B. lenta, isoforms identical or very similar to those with a high IgE-reactivity were found in the pollen proteome of all examined birch species. Consequently, these species are also predicted to be allergenic with regard to Bet v 1 related allergies.

  6. Regulation of cell proliferation by nucleocytoplasmic dynamics of postnatal and embryonic exon-II-containing MBP isoforms

    NARCIS (Netherlands)

    Ozgen, Hande; Kahya, Nicoletta; de Jonge, Jenny C.; Smith, Graham S. T.; Harauz, George; Hoekstra, Dick; Baron, Wia

    2014-01-01

    The only known structural protein required for formation of myelin, produced by oligodendrocytes in the central nervous system, is myelin basic protein (MBP). This peripheral membrane protein has different developmentally-regulated isoforms, generated by alternative splicing. The isoforms are target

  7. Lipoprotein(a) levels, apo(a) isoform size, and coronary heart disease risk in the Framingham Offspring Study

    Science.gov (United States)

    The aim of this study was to assess the independent contributions of plasma levels of lipoprotein(a) [Lp(a)], Lp(a) cholesterol, and of apo(a) isoform size to prospective coronary heart disease (CHD) risk. Plasma Lp(a) and Lp(a) cholesterol levels, and apo(a) isoform size were measured at examinati...

  8. Glucocorticoid receptor translational isoforms underlie maturational stage-specific glucocorticoid sensitivities of dendritic cells in mice and humans.

    Science.gov (United States)

    Cao, Yun; Bender, Ingrid K; Konstantinidis, Athanasios K; Shin, Soon Cheon; Jewell, Christine M; Cidlowski, John A; Schleimer, Robert P; Lu, Nick Z

    2013-02-28

    Although glucocorticoids are a profoundly important class of anti-inflammatory and immunosuppressive agents, their actions in dendritic cells (DCs) are not well understood. We found that dexamethasone, a potent glucocorticoid, selectively induced apoptosis in mature, but not in immature, DCs in healthy mice, in mice with experimental airway inflammation, and in vitro in bone marrow–derived DCs. Distinct glucocorticoid receptor (GR) translational isoforms expressed in immature and mature DCs probably contribute to the DC maturational stage-specific glucocorticoid sensitivity. The GR-D isoforms were the predominant isoforms in immature DCs, whereas the proapoptotic GR-A isoform was the main isoform in mature DCs. Ectopic expression of the GR-A isoform in immature DCs increased glucocorticoid sensitivity and RU486, a selective GR antagonist, inhibited the glucocorticoid sensitivity of mature DCs. Furthermore, the distinct expression pattern of GR isoforms in immature and mature murine DCs was also observed in human monocyte–derived DCs. These studies suggest that glucocorticoids may spare immature DCs and suppress mature DCs and inflammation via differential expression of GR translational isoforms. PMID:23297131

  9. Salivary Gland Thrombostasin Isoforms Differentially Regulate Blood Uptake of Horn Flies Fed on New Zealand White Rabbits

    Science.gov (United States)

    Thrombostasin (TS) is a previously characterized anticlotting protein with multiple isoforms found in the saliva of horn flies. In this report the effects of TS isoforms on blood feeding was assessed with individual flies that carried corresponding ts alleles. Laboratory studies of horn fly blood fe...

  10. Salivary gland thrombostasin isoforms differentilally regulate blood uptake of horn flies fed on New Zealand white rabbits

    Science.gov (United States)

    Thrombostasin (TS) is a previously characterized anticlotting protein with multiple isoforms found in the saliva of horn flies. In this report the effects of TS isoforms on blood feeding was assessed with individual flies that carried corresponding ts alleles. Laboratory studies of horn fly blood fe...

  11. Sulfonamides incorporating heteropolycyclic scaffolds show potent inhibitory action against carbonic anhydrase isoforms I, II, IX and XII.

    Science.gov (United States)

    Barresi, Elisabetta; Salerno, Silvia; Marini, Anna Maria; Taliani, Sabrina; La Motta, Concettina; Simorini, Francesca; Da Settimo, Federico; Vullo, Daniela; Supuran, Claudiu T

    2016-02-15

    Three series of polycyclic compounds possessing either primary sulfonamide or carboxylic acid moieties as zinc-binding groups were investigated as inhibitors of four physiologically relevant CA isoforms, the cytosolic hCA I and II, as well as the transmembrane hCA IX and XII. Most of the new sulfonamides reported here showed excellent inhibitory effects against isoforms hCA II, IX and XII, but no highly isoform-selective inhibition profiles. On the other hand, the carboxylates selectively inhibited hCA IX (KIs ranging between 40.8 and 92.7nM) without inhibiting significantly the other isoforms. Sulfonamides/carboxylates incorporating polycyclic ring systems such as benzothiopyranopyrimidine, pyridothiopyranopyrimidine or dihydrobenzothiopyrano[4,3-c]pyrazole may be considered as interesting candidates for exploring the design of isoform-selective CAIs with various pharmacologic applications. PMID:26796953

  12. The characterization of soybean oil body integral oleosin isoforms and the effects of alkaline pH on them.

    Science.gov (United States)

    Cao, Yanyun; Zhao, Luping; Ying, Yusang; Kong, Xiangzhen; Hua, Yufei; Chen, Yeming

    2015-06-15

    Oil body, an organelle in seed cell (naturally pre-emulsified oil), has great potentials to be used in food, cosmetics, pharmaceutical and other applications requiring stable oil-in-water emulsions. Researchers have tried to extract oil body by alkaline buffers, which are beneficial for removing contaminated proteins. But it is not clear whether alkaline buffers could remove oil body integral proteins (mainly oleosins), which could keep oil body integrity and stability. In this study, seven oleosin isoforms were identified for soybean oil body (three isoforms, 24 kDa; three isoforms, 18 kDa; one isoform, 16kDa). Oleosins were not glycoproteins and 24 kDa oleosin isoforms possessed less thiol groups than 18 kDa ones. It was found that alkaline pH not only removed contaminated proteins but also oleosins, and more and more oleosins were removed with increasing alkaline pH.

  13. Development of isoform-specific sensors of polypeptide GalNAc-transferase activity.

    Science.gov (United States)

    Song, Lina; Bachert, Collin; Schjoldager, Katrine T; Clausen, Henrik; Linstedt, Adam D

    2014-10-31

    Humans express up to 20 isoforms of GalNAc-transferase (herein T1-T20) that localize to the Golgi apparatus and initiate O-glycosylation. Regulation of this enzyme family affects a vast array of proteins transiting the secretory pathway and diseases arise upon misregulation of specific isoforms. Surprisingly, molecular probes to monitor GalNAc-transferase activity are lacking and there exist no effective global or isoform-specific inhibitors. Here we describe the development of T2- and T3-isoform specific fluorescence sensors that traffic in the secretory pathway. Each sensor yielded little signal when glycosylated but was strongly activated in the absence of its glycosylation. Specificity of each sensor was assessed in HEK cells with either the T2 or T3 enzymes deleted. Although the sensors are based on specific substrates of the T2 and T3 enzymes, elements in or near the enzyme recognition sequence influenced their activity and required modification, which we carried out based on previous in vitro work. Significantly, the modified T2 and T3 sensors were activated only in cells lacking their corresponding isozymes. Thus, we have developed T2- and T3-specific sensors that will be valuable in both the study of GalNAc-transferase regulation and in high-throughput screening for potential therapeutic regulators of specific GalNAc-transferases.

  14. Active zone scaffolds differentially accumulate Unc13 isoforms to tune Ca(2+) channel-vesicle coupling.

    Science.gov (United States)

    Böhme, Mathias A; Beis, Christina; Reddy-Alla, Suneel; Reynolds, Eric; Mampell, Malou M; Grasskamp, Andreas T; Lützkendorf, Janine; Bergeron, Dominique Dufour; Driller, Jan H; Babikir, Husam; Göttfert, Fabian; Robinson, Iain M; O'Kane, Cahir J; Hell, Stefan W; Wahl, Markus C; Stelzl, Ulrich; Loll, Bernhard; Walter, Alexander M; Sigrist, Stephan J

    2016-10-01

    Brain function relies on fast and precisely timed synaptic vesicle (SV) release at active zones (AZs). Efficacy of SV release depends on distance from SV to Ca(2+) channel, but molecular mechanisms controlling this are unknown. Here we found that distances can be defined by targeting two unc-13 (Unc13) isoforms to presynaptic AZ subdomains. Super-resolution and intravital imaging of developing Drosophila melanogaster glutamatergic synapses revealed that the Unc13B isoform was recruited to nascent AZs by the scaffolding proteins Syd-1 and Liprin-α, and Unc13A was positioned by Bruchpilot and Rim-binding protein complexes at maturing AZs. Unc13B localized 120 nm away from Ca(2+) channels, whereas Unc13A localized only 70 nm away and was responsible for docking SVs at this distance. Unc13A(null) mutants suffered from inefficient, delayed and EGTA-supersensitive release. Mathematical modeling suggested that synapses normally operate via two independent release pathways differentially positioned by either isoform. We identified isoform-specific Unc13-AZ scaffold interactions regulating SV-Ca(2+)-channel topology whose developmental tightening optimizes synaptic transmission.

  15. The human-specific invariant chain isoform Iip35 modulates Iip33 trafficking and function.

    Science.gov (United States)

    Sand, Kine Marita Knudsen; Landsverk, Ole J B; Berg-Larsen, Axel; Bakke, Oddmund; Gregers, Tone F

    2014-10-01

    The invariant chain (Ii) is a multifunctional protein, which has an essential role in the assembly and transport of major histocompatibility complex class II (MHC II) molecules. From a single gene, Ii is synthesized as four different isoforms: Iip33, Iip35, Iip41 and Iip43. Iip35 and Iip43 are specific to humans, and are formed due to an upstream alternative translation site, resulting in an N-terminal extension of 16 amino acids. This extension harbors a strong endoplasmic reticulum (ER) retention motif. Consequently, Iip35 or Iip43 expressed alone are retained in the ER, whereas Iip33 and Iip41 rapidly traffic to the endosomal pathway. Endogenously expressed, the four isoforms form mixed heterotrimers in the ER; however, mainly due to the absence of the Iip35/p43 isoforms in mice, little is known about how they influence general Ii function. In this study, we have co-expressed Iip33 and Iip35 in human cells with and without MHC II to gain a better understanding of how Iip35 isoform influences the cellular properties of Iip33. We find that Iip35 significantly affects the properties of Iip33. In the presence of Iip35, the transport of Iip33 out of the ER is delayed, its half-life is dramatically prolonged and its ability to induce enlarged endosomes and delayed endosomal maturation is abrogated.

  16. Tyrosinase activity and isoform composition in separate tissues during development of Agaricus bisporus fruit bodies

    NARCIS (Netherlands)

    Leeuwen, van J.; Wichers, H.J.

    1999-01-01

    During growth of Agaricus bisporus fruit bodies the amount of active tyrosinase increased. The amount of active tyrosinase can be related to the degree of browning, as opposed to the fully activated tyrosinase level. Isoelectric focusing revealed that active and latent tyrosinase isoforms having dif

  17. Both Myosin-10 isoforms are required for radial neuronal migration in the developing cerebral cortex.

    Science.gov (United States)

    Ju, Xing-Da; Guo, Ye; Wang, Nan-Nan; Huang, Ying; Lai, Ming-Ming; Zhai, Yan-Hua; Guo, Yu-Guang; Zhang, Jian-Hua; Cao, Rang-Juan; Yu, Hua-Li; Cui, Lei; Li, Yu-Ting; Wang, Xing-Zhi; Ding, Yu-Qiang; Zhu, Xiao-Juan

    2014-05-01

    During embryonic development of the mammalian cerebral cortex, postmitotic cortical neurons migrate radially from the ventricular zone to the cortical plate. Proper migration involves the correct orientation of migrating neurons and the transition from a multipolar to a mature bipolar morphology. Herein, we report that the 2 isoforms of Myosin-10 (Myo10) play distinct roles in the regulation of radial migration in the mouse cortex. We show that the full-length Myo10 (fMyo10) isoform is located in deeper layers of the cortex and is involved in establishing proper migration orientation. We also demonstrate that fMyo10-dependent orientation of radial migration is mediated at least in part by the netrin-1 receptor deleted in colorectal cancer. Moreover, we show that the headless Myo10 (hMyo10) isoform is required for the transition from multipolar to bipolar morphologies in the intermediate zone. Our study reveals divergent functions for the 2 Myo10 isoforms in controlling both the direction of migration and neuronal morphogenesis during radial cortical neuronal migration. PMID:23300110

  18. A mitotic SKAP isoform regulates spindle positioning at astral microtubule plus ends.

    Science.gov (United States)

    Kern, David M; Nicholls, Peter K; Page, David C; Cheeseman, Iain M

    2016-05-01

    The Astrin/SKAP complex plays important roles in mitotic chromosome alignment and centrosome integrity, but previous work found conflicting results for SKAP function. Here, we demonstrate that SKAP is expressed as two distinct isoforms in mammals: a longer, testis-specific isoform that was used for the previous studies in mitotic cells and a novel, shorter mitotic isoform. Unlike the long isoform, short SKAP rescues SKAP depletion in mitosis and displays robust microtubule plus-end tracking, including localization to astral microtubules. Eliminating SKAP microtubule binding results in severe chromosome segregation defects. In contrast, SKAP mutants specifically defective for plus-end tracking facilitate proper chromosome segregation but display spindle positioning defects. Cells lacking SKAP plus-end tracking have reduced Clasp1 localization at microtubule plus ends and display increased lateral microtubule contacts with the cell cortex, which we propose results in unbalanced dynein-dependent cortical pulling forces. Our work reveals an unappreciated role for the Astrin/SKAP complex as an astral microtubule mediator of mitotic spindle positioning. PMID:27138257

  19. Alternative NF-κB Isoforms in the Drosophila Neuromuscular Junction and Brain.

    Directory of Open Access Journals (Sweden)

    Bo Zhou

    Full Text Available The Drosophila NF-κB protein Dorsal is expressed at the larval neuromuscular junction, where its expression appears unrelated to known Dorsal functions in embryonic patterning and innate immunity. Using confocal microscopy with domain-specific antisera, we demonstrate that larval muscle expresses only the B isoform of Dorsal, which arises by intron retention. We find that Dorsal B interacts with and stabilizes Cactus at the neuromuscular junction, but exhibits Cactus independent localization and an absence of detectable nuclear translocation. We further find that the Dorsal-related immune factor Dif encodes a B isoform, reflecting a conservation of B domains across a range of insect NF-κB proteins. Carrying out mutagenesis of the Dif locus via a site-specific recombineering approach, we demonstrate that Dif B is the major, if not sole, Dif isoform in the mushroom bodies of the larval brain. The Dorsal and Dif B isoforms thus share a specific association with nervous system tissues as well as an alternative protein structure.

  20. Recombinant heptameric coatomer complexes: novel tools to study isoform-specific functions.

    NARCIS (Netherlands)

    Sahlmuller, M.C.; Strating, J.R.P.M.; Beck, R.; Eckert, P.; Popoff, V.; Haag, M.; Hellwig, A.; Berger, I.; Brugger, B.; Wieland, F.T.

    2011-01-01

    COPI (coat protein I)-coated vesicles are implicated in various transport steps within the early secretory pathway. The major structural component of the COPI coat is the heptameric complex coatomer (CM). Recently, four isoforms of CM were discovered that may help explain various transport steps in

  1. Subcellular targeting of nine calcium-dependent protein kinase isoforms from Arabidopsis

    Science.gov (United States)

    Dammann, Christian; Ichida, Audrey; Hong, Bimei; Romanowsky, Shawn M.; Hrabak, Estelle M.; Harmon, Alice C.; Pickard, Barbara G.; Harper, Jeffrey F.; Evans, M. L. (Principal Investigator)

    2003-01-01

    Calcium-dependent protein kinases (CDPKs) are specific to plants and some protists. Their activation by calcium makes them important switches for the transduction of intracellular calcium signals. Here, we identify the subcellular targeting potentials for nine CDPK isoforms from Arabidopsis, as determined by expression of green fluorescent protein (GFP) fusions in transgenic plants. Subcellular locations were determined by fluorescence microscopy in cells near the root tip. Isoforms AtCPK3-GFP and AtCPK4-GFP showed a nuclear and cytosolic distribution similar to that of free GFP. Membrane fractionation experiments confirmed that these isoforms were primarily soluble. A membrane association was observed for AtCPKs 1, 7, 8, 9, 16, 21, and 28, based on imaging and membrane fractionation experiments. This correlates with the presence of potential N-terminal acylation sites, consistent with acylation as an important factor in membrane association. All but one of the membrane-associated isoforms targeted exclusively to the plasma membrane. The exception was AtCPK1-GFP, which targeted to peroxisomes, as determined by covisualization with a peroxisome marker. Peroxisome targeting of AtCPK1-GFP was disrupted by a deletion of two potential N-terminal acylation sites. The observation of a peroxisome-located CDPK suggests a mechanism for calcium regulation of peroxisomal functions involved in oxidative stress and lipid metabolism.

  2. Synthesis of Benzofuran Analogue of Go6976, an Isoform Selective Protein Kinase C Inhibitor

    Institute of Scientific and Technical Information of China (English)

    MA, Da-Wei; ZHANG, Xin-Rong; WU, Shi-Hui; TAO, Feng-Gang

    2001-01-01

    Based on the structure of Go6976, a known isoform-selective protein kinase C inhibitor, a benzofuran analogue (1) was designed. This analogue was synthesized by coupling of benzofuran 3-acetic acid and 8-oxo-tryptamine and subsequent intramolecular Dieckmann condensation, alkylation, oxidative photocyclization and cyanation reaction of mesylate.

  3. Functions of Glutamine Synthetase Isoforms in the Nitrogen Metabolism of Plants

    DEFF Research Database (Denmark)

    Guan, Miao

    ;2 which encode different isoforms of the key N-assimilatory enzyme cytosolic glutamine synthetase (GS1). In the single knockout mutant gln1;2 and in the double knockout mutant gln1;1:gln1;2, seed germination and seedling establishment were distinctly impaired. The negative effect of Gln1;2 deficiency...

  4. Translational control of SCL-isoform expression in hematopoietic lineage choice

    NARCIS (Netherlands)

    Calkhoven, Cornelis F; Muller, Christine; Martin, Richard; Krosl, Goradz; Pietsch, Hubertus; Hoang, Trang; Leutz, Achim

    2003-01-01

    We investigated the translational regulation of SCL protein expression and its role in hematopoietic lineage choice. We show that the expression of different SCL protein isoforms is regulated by signal transduction pathways that modulate translation initiation factor (eIF) function. A conserved smal

  5. Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform

    NARCIS (Netherlands)

    Laarakkers, C.M.; Wiegerinck, E.T.G.; Klaver, S.; Kolodziejczyk, M.; Gille, H.; Hohlbaum, A.M.; Tjalsma, H.; Swinkels, D.W.

    2013-01-01

    Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role

  6. Cloning, Sequencing, and the Expression of the Elusive Sarcomeric TPM4α Isoform in Humans

    Science.gov (United States)

    Abbott, Lynn; Alshiekh-Nasany, Ruham; Mitschow, Charles

    2016-01-01

    In mammals, tropomyosin is encoded by four known TPM genes (TPM1, TPM2, TPM3, and TPM4) each of which can generate a number of TPM isoforms via alternative splicing and/or using alternate promoters. In humans, the sarcomeric isoform(s) of each of the TPM genes, except for the TPM4, have been known for a long time. Recently, on the basis of computational analyses of the human genome sequence, the predicted sequence of TPM4α has been posted in GenBank. We designed primer-pairs for RT-PCR and showed the expression of the transcripts of TPM4α and a novel isoform TPM4δ in human heart and skeletal muscle. qRT-PCR shows that the relative expression of TPM4α and TPM4δ is higher in human cardiac muscle. Western blot analyses using CH1 monoclonal antibodies show the absence of the expression of TPM4δ protein (~28 kDa) in human heart muscle. 2D western blot analyses with the same antibody show the expression of at least nine distinct tropomyosin molecules with a mass ~32 kD and above in adult heart. By Mass spectrometry, we determined the amino acid sequences of the extracted proteins from these spots. Spot “G” reveals the putative expression of TPM4α along with TPM1α protein in human adult heart. PMID:27703814

  7. Cloning, Sequencing, and the Expression of the Elusive Sarcomeric TPM4α Isoform in Humans

    Directory of Open Access Journals (Sweden)

    Dipak K. Dube

    2016-01-01

    Full Text Available In mammals, tropomyosin is encoded by four known TPM genes (TPM1, TPM2, TPM3, and TPM4 each of which can generate a number of TPM isoforms via alternative splicing and/or using alternate promoters. In humans, the sarcomeric isoform(s of each of the TPM genes, except for the TPM4, have been known for a long time. Recently, on the basis of computational analyses of the human genome sequence, the predicted sequence of TPM4α has been posted in GenBank. We designed primer-pairs for RT-PCR and showed the expression of the transcripts of TPM4α and a novel isoform TPM4δ in human heart and skeletal muscle. qRT-PCR shows that the relative expression of TPM4α and TPM4δ is higher in human cardiac muscle. Western blot analyses using CH1 monoclonal antibodies show the absence of the expression of TPM4δ protein (~28 kDa in human heart muscle. 2D western blot analyses with the same antibody show the expression of at least nine distinct tropomyosin molecules with a mass ~32 kD and above in adult heart. By Mass spectrometry, we determined the amino acid sequences of the extracted proteins from these spots. Spot “G” reveals the putative expression of TPM4α along with TPM1α protein in human adult heart.

  8. A novel MCPH1 isoform complements the defective chromosome condensation of human MCPH1-deficient cells.

    Directory of Open Access Journals (Sweden)

    Ioannis Gavvovidis

    Full Text Available Biallelic mutations in MCPH1 cause primary microcephaly (MCPH with the cellular phenotype of defective chromosome condensation. MCPH1 encodes a multifunctional protein that notably is involved in brain development, regulation of chromosome condensation, and DNA damage response. In the present studies, we detected that MCPH1 encodes several distinct transcripts, including two major forms: full-length MCPH1 (MCPH1-FL and a second transcript lacking the six 3' exons (MCPH1Δe9-14. Both variants show comparable tissue-specific expression patterns, demonstrate nuclear localization that is mediated independently via separate NLS motifs, and are more abundant in certain fetal than adult organs. In addition, the expression of either isoform complements the chromosome condensation defect found in genetically MCPH1-deficient or MCPH1 siRNA-depleted cells, demonstrating a redundancy of both MCPH1 isoforms for the regulation of chromosome condensation. Strikingly however, both transcripts are regulated antagonistically during cell-cycle progression and there are functional differences between the isoforms with regard to the DNA damage response; MCPH1-FL localizes to phosphorylated H2AX repair foci following ionizing irradiation, while MCPH1Δe9-14 was evenly distributed in the nucleus. In summary, our results demonstrate here that MCPH1 encodes different isoforms that are differentially regulated at the transcript level and have different functions at the protein level.

  9. Titin isoforms and kinematics of fast swimming carp larvae (Cyprinus carpio L.)

    NARCIS (Netherlands)

    Spierts, I.L.Y.

    2001-01-01

    Titin, a striated-muscle specific protein spanning the distance between Z- and M-lines of sarcomeres, is held responsible for developing passive tension and for maintaining the central position of thick filaments in contracting sarcomeres. Different muscles express titin isoforms of different molecu

  10. Squamous cell carcinoma antigen isoforms in serum from cervical cancer patients

    NARCIS (Netherlands)

    Roijer, E; de Bruijn, HWA; Dahlen, U; ten Hoor, K; Lundin, M; Nilsson, K; Soderstrom, K; Nilsson, O

    2006-01-01

    Squamous cell carcinoma antigen (SCCA) is a serological marker of squamous cell carcinomas (SCC). To study whether any of the SCCA isoforms would provide additional and more specific/sensitive clinical information than total SCCA, immunoassays specific for the different forms of SCCA (free SCCA2, to

  11. Role of PRMTs in cancer: Could minor isoforms be leaving a mark?

    Institute of Scientific and Technical Information of China (English)

    R; Mitchell; Baldwin; Alan; Morettin; Jocelyn; C?té

    2014-01-01

    Protein arginine methyltransferases(PRMTs) catalyze the methylation of a variety of protein substrates, many of which have been linked to the development, progression and aggressiveness of different types of cancer. Moreover, aberrant expression of PRMTs has been observed in several cancer types. While the link between PRMTs and cancer is a relatively new area of interest, the functional implications documented thus far warrant further investigations into its therapeutic potential. However, the expression of these enzymes and the regulation of their activity in cancer are still significantly understudied. Currently there are nine main members of the PRMT family. Further, the existence of alternatively spliced isoforms for several of these family members provides an additional layer of complexity. Specifically, PRMT1, PRMT2, CARM1 and PRMT7 have been shown to have alternative isoforms and others may be currently unrealized. Our knowledge with respect to the relative expression and the specific functions of these isoforms is largely lacking and needs attention. Here we present a review of the current knowledge of theknown alternative PRMT isoforms and provide a rationale for how they may impact on cancer and represent potentially useful targets for the development of novel therapeutic strategies.

  12. Effect of renal replacement therapy on retinol-binding protein 4 isoforms

    DEFF Research Database (Denmark)

    Frey, Simone K; Henze, Andrea; Nagl, Britta;

    2009-01-01

    Retinol-binding protein 4 (RBP4) levels are elevated in the serum of patients with kidney dysfunction. We recently showed that RBP4 isoforms including apo-RBP4 (RBP4 not bound to retinol) and RBP4 truncated at the C-terminus (RBP4-L, RBP4-LL) are increased in the serum of patients with kidney dis...

  13. Diagnostic Accuracy of Cerebrospinal Fluid Amyloid-beta Isoforms for Early and Differential Dementia Diagnosis

    NARCIS (Netherlands)

    Struyfs, Hanne; Van Broeck, Bianca; Timmers, Maarten; Fransen, Erik; Sleegers, Kristel; Van Broeckhoven, Christine; De Deyn, Peter P.; Streffer, Johannes R.; Mercken, Marc; Engelborghs, Sebastiaan

    2015-01-01

    Background: Overlapping cerebrospinal fluid biomarkers (CSF) levels between Alzheimer's disease (AD) and non-AD patients decrease differential diagnostic accuracy of the AD core CSF biomarkers. Amyloid-beta (A beta) isoforms might improve the AD versus non-AD differential diagnosis. Objective: To de

  14. Differential expression of polycytosine-binding protein isoforms in adrenal gland, locus coeruleus and midbrain.

    Science.gov (United States)

    Boschi, N M; Takeuchi, K; Sterling, C; Tank, A W

    2015-02-12

    Polycytosine-binding proteins (PCBPs) are RNA-binding proteins that participate in post-transcriptional control pathways. Among the diverse functions of these proteins is the interaction with a 27 nucleotide pyrimidine-rich domain within the 3'UTR of tyrosine hydroxylase (TH) mRNA. Mutations to this domain result in decreased stability of TH mRNA and loss of cAMP-mediated activation of TH mRNA translation. PCBPs are hypothesized to play key roles in these regulatory mechanisms. In order to further test this hypothesis, we examined the tissue distribution of PCBPs in catecholaminergic cells. Initial studies demonstrated that proteins from catecholaminergic tissues bind to TH mRNA 3'UTR sequences and these proteins have an apparent Mr of ∼ 44 kDa, which is close to the molecular sizes for PCBPs. Fluorescent immunohistochemistry and confocal microscopy was used to analyze the distribution of PCBP isoforms in TH-positive cells of the rat midbrain, locus coeruleus, and adrenal gland. Our results suggest that: (1) PCBP2 is the predominant isoform in TH-positive cells of the rat midbrain; (2) PCBP3 is the predominant isoform in TH-positive cells of the locus coeruleus; and (3) PCBP1 is the predominant isoform in the adrenal medulla. The localization of PCBP proteins to TH-positive cells in these catecholaminergic tissues is consistent with the hypothesis that PCBPs play a role in the regulation of TH expression.

  15. Heparanase isoform expression and extracellular matrix remodeling in intervertebral disc degenerative disease

    Directory of Open Access Journals (Sweden)

    Luciano Miller Reis Rodrigues

    2011-01-01

    Full Text Available OBJECTIVE: To determine the molecules involved in extracellular matrix remodeling and to identify and quantify heparanase isoforms present in herniated and degenerative discs. INTRODUCTION: Heparanase is an endo-beta-glucuronidase that specifically acts upon the heparan sulfate chains of proteoglycans. However, heparanase expression in degenerative intervertebral discs has not yet been evaluated. Notably, previous studies demonstrated a correlation between changes in the heparan sulfate proteoglycan pattern and the degenerative process associated with intervertebral discs. METHODS: Twenty-nine samples of intervertebral degenerative discs, 23 samples of herniated discs and 12 samples of non-degenerative discs were analyzed. The expression of both heparanase isoforms (heparanase-1 and heparanase-2 was evaluated using immunohistochemistry and real-time RT-PCR analysis. RESULTS: Heparanase-1 and heparanase-2 expression levels were significantly higher in the herniated and degenerative discs in comparison to the control tissues, suggesting a possible role of these proteins in the intervertebral degenerative process. CONCLUSION: The overexpression of heparanase isoforms in the degenerative intervertebral discs and the herniated discs suggests a potential role of both proteins in the mediation of inflammatory processes and in extracellular matrix remodeling. The heparanase-2 isoform may be involved in normal metabolic processes, as evidenced by its higher expression in the control intervertebral discs relative to the expression of heparanase-1.

  16. Novel Kidins220/ARMS Splice Isoforms: Potential Specific Regulators of Neuronal and Cardiovascular Development.

    Directory of Open Access Journals (Sweden)

    Nathalie Schmieg

    Full Text Available Kidins220/ARMS is a transmembrane protein playing a crucial role in neuronal and cardiovascular development. Kidins220/ARMS is a downstream target of neurotrophin receptors and interacts with several signalling and trafficking factors. Through computational modelling, we found two potential sites for alternative splicing of Kidins220/ARMS. The first is located between exon 24 and exon 29, while the second site replaces exon 32 by a short alternative terminal exon 33. Here we describe the conserved occurrence of several Kidins220/ARMS splice isoforms at RNA and protein levels. Kidins220/ARMS splice isoforms display spatio-temporal regulation during development with distinct patterns in different neuronal populations. Neurotrophin receptor stimulation in cortical and hippocampal neurons and neuroendocrine cells induces specific Kidins220/ARMS splice isoforms and alters the appearance kinetics of the full-length transcript. Remarkably, alternative terminal exon splicing generates Kidins220/ARMS variants with distinct cellular localisation: Kidins220/ARMS containing exon 32 is targeted to the plasma membrane and neurite tips, whereas Kidins220/ARMS without exon 33 mainly clusters the full-length protein in a perinuclear intracellular compartment in PC12 cells and primary neurons, leading to a change in neurotrophin receptor expression. Overall, this study demonstrates the existence of novel Kidins220/ARMS splice isoforms with unique properties, revealing additional complexity in the functional regulation of neurotrophin receptors, and potentially other signalling pathways involved in neuronal and cardiovascular development.

  17. The endogenous anti-angiogenic VEGF isoform, VEGF165b inhibits human tumour growth in mice.

    NARCIS (Netherlands)

    Rennel, E.; Waine, E.; Guan, H.; Schuler, Y.; Leenders, W.P.J.; Woolard, J.; Sugiono, M.; Gillatt, D.; Kleinerman, E.; Bates, D.; Harper, S.

    2008-01-01

    Vascular endothelial growth factor-A is widely regarded as the principal stimulator of angiogenesis required for tumour growth. VEGF is generated as multiple isoforms of two families, the pro-angiogenic family generated by proximal splice site selection in the terminal exon, termed VEGFxxx, and the

  18. Plectin isoform 1b mediates mitochondrion-intermediate filament network linkage and controls organelle shape.

    Science.gov (United States)

    Winter, Lilli; Abrahamsberg, Christina; Wiche, Gerhard

    2008-06-16

    Plectin is a versatile intermediate filament (IF)-bound cytolinker protein with a variety of differentially spliced isoforms accounting for its multiple functions. One particular isoform, plectin 1b (P1b), remains associated with mitochondria after biochemical fractionation of fibroblasts and cells expressing exogenous P1b. Here, we determined that P1b is inserted into the outer mitochondrial membrane with the exon 1b-encoded N-terminal sequence serving as a mitochondrial targeting and anchoring signal. To study P1b-related mitochondrial functions, we generated mice that selectively lack this isoform but express all others. In primary fibroblasts and myoblasts derived from these mice, we observe a substantial elongation of mitochondrial networks, whereas other mitochondrial properties remain largely unaffected. Normal morphology of mitochondria could be restored by isoform-specific overexpression of P1b in P1b-deficient as well as plectin-null cells. We propose a model where P1b both forms a mitochondrial signaling platform and affects organelle shape and network formation by tethering mitochondria to IFs.

  19. Selective expression of myosin IC Isoform A in mouse and human cell lines and mouse prostate cancer tissues.

    Directory of Open Access Journals (Sweden)

    Ivanna Ihnatovych

    Full Text Available Myosin IC is a single headed member of the myosin superfamily. We recently identified a novel isoform and showed that the MYOIC gene in mammalian cells encodes three isoforms (isoforms A, B, and C. Furthermore, we demonstrated that myosin IC isoform A but not isoform B exhibits a tissue specific expression pattern. In this study, we extended our analysis of myosin IC isoform expression patterns by analyzing the protein and mRNA expression in various mammalian cell lines and in various prostate specimens and tumor tissues from the transgenic mouse prostate (TRAMP model by immunoblotting, qRT-PCR, and by indirect immunohistochemical staining of paraffin embedded prostate specimen. Analysis of a panel of mammalian cell lines showed an increased mRNA and protein expression of specifically myosin IC isoform A in a panel of human and mouse prostate cancer cell lines but not in non-cancer prostate or other (non-prostate- cancer cell lines. Furthermore, we demonstrate that myosin IC isoform A expression is significantly increased in TRAMP mouse prostate samples with prostatic intraepithelial neoplasia (PIN lesions and in distant site metastases in lung and liver when compared to matched normal tissues. Our observations demonstrate specific changes in the expression of myosin IC isoform A that are concurrent with the occurrence of prostate cancer in the TRAMP mouse prostate cancer model that closely mimics clinical prostate cancer. These data suggest that elevated levels of myosin IC isoform A may be a potential marker for the detection of prostate cancer.

  20. Conformational difference in human IgG2 disulfide isoforms revealed by hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Zhang, Aming; Fang, Jing; Chou, Robert Y-T; Bondarenko, Pavel V; Zhang, Zhongqi

    2015-03-17

    Both recombinant and natural human IgG2 antibodies have several different disulfide bond isoforms, which possess different global structures, thermal stabilities, and biological activities. A detailed mapping of the structural difference among IgG2 disulfide isoforms, however, has not been established. In this work, we employed hydrogen/deuterium exchange mass spectrometry to study the conformation of three major IgG2 disulfide isoforms known as IgG2-B, IgG2-A1, and IgG2-A2 in two recombinant human IgG2 monoclonal antibodies. By comparing the protection factors between amino acid residues in isoforms B and A1 (the classical form), we successfully identified several local regions in which the IgG2-B isoform showed more solvent protection than the IgG2-A1 isoform. On the basis of three-dimensional structural models of IgG2, these identified regions were located on the Fab domains, close to the hinge, centered on the side where the two Fab arms faced each other in spatial proximity. We speculated that in the more solvent-protected B isoform, the two Fab arms were brought into contact by the nonclassical disulfide bonds, resulting in a more compact global structure. Loss of Fab domain flexibility in IgG2-B could limit its ability to access cell-surface epitopes, leading to reduced antigen binding potency. The A2 isoform was previously found to have disulfide linkages similar to those of the classical A1 isoform, but with different biophysical behaviors. Our data indicated that, compared to IgG2-A1, IgG2-A2 had less solvent protection in some heavy-chain Fab regions close the hinge, suggesting that the A2 isoform had more flexible Fab domains. PMID:25730439

  1. mRNA expression of diacylglycerol kinase isoforms in insulin-sensitive tissues: effects of obesity and insulin resistance.

    Science.gov (United States)

    Mannerås-Holm, Louise; Kirchner, Henriette; Björnholm, Marie; Chibalin, Alexander V; Zierath, Juleen R

    2015-04-01

    Diacylglycerol kinase (DGK) isoforms regulate signal transduction and lipid metabolism. DGKδ deficiency leads to hyperglycemia, peripheral insulin resistance, and metabolic inflexibility. Thus, dysregulation of other DGK isoforms may play a role in metabolic dysfunction. We investigated DGK isoform mRNA expression in extensor digitorum longus (EDL) and soleus muscle, liver as well as subcutaneous and epididymal adipose tissue in C57BL/6J mice and obese and insulin-resistant ob/ob mice. All DGK isoforms, except for DGKκ, were detectable, although with varying mRNA expression. Liver DGK expression was generally lowest, with several isoforms undetectable. In soleus muscle, subcutaneous and epididymal adipose tissue, DGKδ was the most abundant isoform. In EDL muscle, DGKα and DGKζ were the most abundant isoforms. In liver, DGKζ was the most abundant isoform. Comparing obese insulin-resistant ob/ob mice to lean C57BL/6J mice, DGKβ, DGKι, and DGKθ were increased and DGKε expression was decreased in EDL muscle, while DGKβ, DGKη and DGKθ were decreased and DGKδ and DGKι were increased in soleus muscle. In liver, DGKδ and DGKζ expression was increased in ob/ob mice. DGKη was increased in subcutaneous fat, while DGKζ was increased and DGKβ, DGKδ, DGKη and DGKε were decreased in epididymal fat from ob/ob mice. In both adipose tissue depots, DGKα and DGKγ were decreased and DGKι was increased in ob/ob mice. In conclusion, DGK mRNA expression is altered in an isoform- and tissue-dependent manner in obese insulin-resistant ob/ob mice. DGK isoforms likely have divergent functional roles in distinct tissues, which may contribute to metabolic dysfunction. PMID:25847921

  2. Two Distinct Isoforms of Matrix Metalloproteinase-2 Are Associated with Human Delayed Kidney Graft Function.

    Directory of Open Access Journals (Sweden)

    Shaynah Wanga

    Full Text Available Delayed graft function (DGF is a frequent complication of renal transplantation, particularly in the setting of transplantation of kidneys derived from deceased donors and expanded-criteria donors. DGF results from tubular epithelial cell injury and has immediate and long term consequences. These include requirement for post-transplantation dialysis, increased incidence of acute rejection, and poorer long-term outcomes. DGF represents one of the clearest clinical examples of renal acute ischemia/reperfusion injury. Experimental studies have demonstrated that ischemia/reperfusion injury induces the synthesis of the full length secreted isoform of matrix metalloproteinase-2 (FL-MMP-2, as well as an intracellular N-terminal truncated MMP-2 isoform (NTT-MMP-2 that initiates an innate immune response. We hypothesized that the two MMP-2 isoforms mediate tubular epithelial cell injury in DGF. Archival renal biopsy sections from 10 protocol biopsy controls and 41 cases with a clinical diagnosis of DGF were analyzed for the extent of tubular injury, expression of the FL-MMP-2 and NTT-MMP-2 isoforms by immunohistochemistry (IHC, in situ hybridization, and qPCR to determine isoform abundance. Differences in transcript abundance were related to tubular injury score. Markers of MMP-2-mediated injury included TUNEL staining and assessment of peritubular capillary density. There was a clear relationship between tubular epithelial cell expression of both FL-MMP-2 and NTT-MMP-2 IHC with the extent of tubular injury. The MMP-2 isoforms were detected in the same tubular segments and were present at sites of tubular injury. qPCR demonstrated highly significant increases in both the FL-MMP-2 and NTT-MMP-2 transcripts. Statistical analysis revealed highly significant associations between FL-MMP-2 and NTT-MMP-2 transcript abundance and the extent of tubular injury, with NTT-MMP-2 having the strongest association. We conclude that two distinct MMP-2 isoforms are

  3. Kalrn promoter usage and isoform expression respond to chronic cocaine exposure

    Directory of Open Access Journals (Sweden)

    Ma Xin-Ming

    2011-02-01

    Full Text Available Abstract Background The long-term effects of cocaine on behavior are accompanied by structural changes in excitatory glutamatergic synapses onto the medium spiny neurons of the striatum. The Kalrn gene encodes several functionally distinct isoforms; these multidomain guanine nucleotide exchange factors (GEFs contain additional domains known to interact with phosphatidylinositides as well as with a number of different proteins. Through their activation of Rho proteins and their interactions with other proteins, the different Kalirin isoforms affect cytoskeletal organization. Chronic exposure of adult male rodents to cocaine increases levels of Kalirin 7 in the striatum. When exposed chronically to cocaine, mice lacking Kalirin 7, the major adult isoform, fail to show an increase in dendritic spine density in the nucleus accumbens, show diminished place preference for cocaine, and exhibit increased locomotor activity in response to cocaine. Results The use of alternate promoters and 3'-terminal exons of the mouse Kalrn gene were investigated using real-time quantitative polymerase chain reaction. While the two most distal full-length Kalrn promoters are used equally in the prefrontal cortex, the more proximal of these promoters accounts for most of the transcripts expressed in the nucleus accumbens. The 3'-terminal exon unique to the Kalirin 7 isoform accounts for a greater percentage of the Kalrn transcripts in prefrontal cortex than in nucleus accumbens. Western blot analyses confirmed these differences. Chronic cocaine treatment increases usage of the promoter encoding the Δ-Kalirin isoforms but does not alter full-length Kalirin promoter usage. Usage of the 3'-terminal exon unique to Kalirin 7 increases following chronic cocaine exposure. Conclusions Kalrn promoter and 3'-terminal exon utilization are region-specific. In the nucleus accumbens, cocaine-mediated alterations in promoter usage and 3'-terminal exon usage favor expression of

  4. Arabidopsis Profilin Isoforms, PRF1 and PRF2Show Distinctive Binding Activities and Subcellular Distributions

    Institute of Scientific and Technical Information of China (English)

    Feng Wang; Yanping Jing; Zhen Wang; Tonglin Mao; Jozef (S)amaj; Ming Yuan; Haiyun Ren

    2009-01-01

    Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fluorescent protein (GFP) tag and expressed in Escherichia coli and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgsnic A. thaliana lines revealed that 35S::GFP-PRF1 formed a filamentous network, while 35S::GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profllin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive Iocalizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.

  5. Survivin isoforms and clinicopathological characteristics in colorectal adenocarcinomas using real-time qPCR

    Science.gov (United States)

    Pavlidou, Anastasia; Dalamaga, Maria; Kroupis, Christos; Konstantoudakis, George; Belimezi, Maria; Athanasas, George; Dimas, Kleanthi

    2011-01-01

    AIM: To investigate three isoforms of survivin in colorectal adenocarcinomas. METHODS: We used the LightCycler Technology (Roche), along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler-Red fluorophore (LC-Red 640). Real time quantitative polymerase chain reaction (PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues. In the patients group, carcinoembryonic antigen (CEA) and CA19-9 tumor markers were also measured immunochemically. RESULTS: Wild type survivin mRNA isoform was expressed in 48% of the 52 tumor samples, survivin-2b in 38% and survivin-ΔΕx3 in 29%, while no expression was found in normal tissues. The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b, survivin-ΔΕx3, survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin (P < 0.001). The mRNA expression of wild-survivin and survivin-ΔΕx3 was related with tumor size and invasion (P = 0.006 and P < 0.005, respectively). A significant difference was found between survivin-2b and morphologic cancer type. Also, the ratio of survivin-ΔEx3/wild-survivin was significantly associated with prognosis. No association was observed between the three isoforms and grade, metastasis, Dukes stage and gender. The three isoforms were not correlated with CEA and CA19-9. CONCLUSION: Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer. PMID:21472129

  6. Isoform-specific proteasomal degradation of Rbfox3 during chicken embryonic development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kee K.; Adelstein, Robert S.; Kawamoto, Sachiyo, E-mail: kawamots@mail.nih.gov

    2014-08-08

    Highlights: • Protein stability of Rbfox3 splice isoforms is differentially regulated. • Rbfox3-d31, an Rbfox3 isoform lacking the RRM, is highly susceptible to degradation. • The protein stability of Rbfox3-d31 is regulated by the ubiquitin–proteasome pathway. • Rbfox3-d31 inhibits the nuclear localization of Rbfox2. • Rbfox3-d31 inhibits the splicing activity of Rbfox2. - Abstract: Rbfox3, a neuron-specific RNA-binding protein, plays an important role in neuronal differentiation during development. An isoform Rbfox3-d31, which excludes the 93-nucleotide cassette exon within the RNA recognition motif of chicken Rbfox3, has been previously identified. However, the cellular functions of Rbfox3-d31 remain largely unknown. Here we find that Rbfox3-d31 mRNA is highly expressed during the early developmental stages of the chicken embryo, while Rbfox3-d31 protein is barely detected during the same stage due to its rapid degradation mediated by the ubiquitin–proteasome pathway. Importantly, this degradation is specific to the Rbfox3-d31 isoform and it does not occur with full-length Rbfox3. Furthermore, suppression of Rbfox3-d31 protein degradation with the proteasome inhibitor MG132 attenuates the splicing activity of another Rbfox family member Rbfox2 by altering the subcellular localization of Rbfox2. These results suggest that Rbfox3-d31 functions as a repressor for the splicing activity of the Rbfox family and its protein level is regulated in an isoform-specific manner in vivo.

  7. Knockout mutants as a tool to identify the subunit composition of Arabidopsis glutamine synthetase isoforms.

    Science.gov (United States)

    Dragićević, Milan; Todorović, Slađana; Bogdanović, Milica; Filipović, Biljana; Mišić, Danijela; Simonović, Ana

    2014-06-01

    Glutamine synthetase (GS) is a key enzyme in nitrogen assimilation, which catalyzes the formation of glutamine from ammonia and glutamate. Plant GS isoforms are multimeric enzymes, recently shown to be decamers. The Arabidopsis genome encodes five cytosolic (GS1) proteins labeled as GLN1;1 through GLN1;5 and one chloroplastic (GS2) isoform, GLN2;0. However, as many as 11 GS activity bands were resolved from different Arabidopsis tissues by Native PAGE and activity staining. Western analysis showed that all 11 isoforms are composed exclusively of 40 kDa GS1 subunits. Of five GS1 genes, only GLN1;1, GLN1;2 and GLN1;3 transcripts accumulated to significant levels in vegetative tissues, indicating that only subunits encoded by these three genes produce the 11-band zymogram. Even though the GS2 gene also had significant expression, the corresponding activity was not detected, probably due to inactivation. To resolve the subunit composition of 11 active GS1 isoforms, homozygous knockout mutants deficient in the expression of different GS1 genes were selected from the progeny of T-DNA insertional SALK and SAIL lines. Comparison of GS isoenzyme patterns of the selected GS1 knockout mutants indicated that all of the detected isoforms consist of varying proportions of GLN1;1, GLN1;2 and GLN1;3 subunits, and that GLN1;1 and GLN1;3, as well as GLN1;2 and GLN1;3 and possibly GLN1;1 and GLN1;2 proteins combine in all proportions to form active homo- and heterodecamers.

  8. Muscle Specific Fragile X Related Protein 1 Isoforms are Sequestered in the Nucleus of Undifferentiated Myoblast

    Directory of Open Access Journals (Sweden)

    Khandjian Edouard W

    2000-12-01

    Full Text Available Abstract Background The family of Fragile X Mental Retardation Proteins is composed of three members: Fragile Mental Retardation 1, Fragile X Related 1 and X Related 2 proteins. These proteins are associated with mRNPs within translating ribosomes and have the capacity to shuttle between the nucleus and the cytoplasm. Great attention has been given to FMRP due to its implication in human hereditary mental retardation while FXR1P and FXR2P have only recently been studied. Results Using antibodies directed against several epitopes of FXR1P, we have detected protein isoforms generated by small peptides pocket inserts. Four isoforms of MW 70, 74, 78, 80 kDa are widely distributed in mouse organs, while in striated muscles these isoforms are replaced by proteins of 82 and 84 kDa containing an extra pocket of 27 aa. Expression of these muscle isoforms is an early event during in vitro differentiation of myoblasts into myotubes and correlates with the activation of muscle-specific genes. However, while FXR1P82,84 are associated with cytoplasmic mRNPs in myotubes, they are sequestered in the nuclei of undifferentiated myoblasts. These observations suggest that, in addition to a cytoplasmic function yet to be defined, FXR1P82,84 may play a nuclear role in pre-mRNA metabolism. Conclusions The pattern of subcellular partitioning of FXR1P isoforms during myogenesis is unique among the family of the FXR proteins. The model system described here should be considered as a powerful tool for ongoing attempts to unravel structure-function relationships of the different FMR family members since the potential role(s of FXR1P as a compensatory factor in Fragile X syndrome is still elusive.

  9. Survivin isoforms and clinicopathological characteristics in colorectal adenocarcinomas using real-time qPCR

    Institute of Scientific and Technical Information of China (English)

    Anastasia Pavlidou; Maria Dalamaga; Christos Kroupis; George Konstantoudakis; Maria Belimezi; George Athanasas; Kleanthi Dimas

    2011-01-01

    AIM: To investigate three isoforms of survivin in colorectal adenocarcinomas. METHODS: We used the LightCycler Technology (Roche), along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler- Red fluorophore (LC-Red 640). Real time quantitative polymerase chain reaction (PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues. In the patients group, carcinoembryonic antigen (CEA) and CA19-9 tumor markers were also measured immunochemically. RESULTS: Wild type survivin mRNA isoform was expressed in 48% of the 52 tumor samples, survivin-2b in 38% and survivin-ΔΕx3 in 29%, while no expression was found in normal tissues. The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b, survivin-ΔΕx3, survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin (P < 0.001). The mRNA expression of wildsurvivin and survivin-ΔΕx3 was related with tumor size and invasion (P = 0.006 and P < 0.005, respectively). A significant difference was found between survivin-2b and morphologic cancer type. Also, the ratio of survivin-ΔEx3/ wild-survivin was significantly associated with prognosis. No association was observed between the three isoforms and grade, metastasis, Dukes stage and gender. The three isoforms were not correlated with CEA and CA19-9. CONCLUSION: Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer.

  10. Remarkable Role of Indoleamine 2,3-Dioxygenase and Tryptophan Metabolites in Infectious Diseases: Potential Role in Macrophage-Mediated Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Yuki Murakami

    2013-01-01

    Full Text Available Indoleamine 2,3-dioxygenase 1 (IDO1, the L-tryptophan-degrading enzyme, plays a key role in the immunomodulatory effects on several types of immune cells. Originally known for its regulatory function during pregnancy and chronic inflammation in tumorigenesis, the activity of IDO1 seems to modify the inflammatory state of infectious diseases. The pathophysiologic activity of L-tryptophan metabolites, kynurenines, is well recognized. Therefore, an understanding of the regulation of IDO1 and the subsequent biochemical reactions is essential for the design of therapeutic strategies in certain immune diseases. In this paper, current knowledge about the role of IDO1 and its metabolites during various infectious diseases is presented. Particularly, the regulation of type I interferons (IFNs production via IDO1 in virus infection is discussed. This paper offers insights into new therapeutic strategies in the modulation of viral infection and several immune-related disorders.

  11. Changes in type II procollagen isoform expression during chondrogenesis by disruption of an alternative 5’ splice site within Col2a1 exon 2

    OpenAIRE

    Hering, Thomas M.; Wirthlin, Louisa; Ravindran, Soumya; McAlinden, Audrey

    2014-01-01

    This study describes a new mechanism controlling the production of alternatively-spliced isoforms of type II procollagen (Col2a1) in vivo. During chondrogenesis, precursor chondrocytes predominantly produce isoforms containing alternatively-spliced exon 2 (type IIA and IID) while Col2a1 mRNA devoid of exon 2 (type IIB) is the major isoform produced by differentiated chondrocytes. We previously identified an additional Col2a1 isoform containing a truncated exon 2 and premature termination codo...

  12. The prognostic significance of indoleamine-2,3-dioxygenase and the receptors for transforming growth factor β and interferon γ in metastatic lymph nodes in malignant melanoma.

    Science.gov (United States)

    Pelak, Maciej J; Śnietura, Mirosław; Lange, Dariusz; Nikiel, Barbara; Pecka, Katarzyna M

    2015-12-01

    We analyzed the prognostic significance of indoleamine-2,3-dioxygenase (IDO) and type 1 receptors for transforming growth factor beta (TGF-βR1) and interferon gamma (IFN-γR1) in resected nodal metastases of 48 malignant melanoma patients. In 32 cases the corresponding skin tumors were available. We used immunohistochemical (IHC) staining which was assessed by pathologists and by a computer-aided algorithm that yielded quantitative results, both absolute and relative. We correlated the results with the patient outcome. We identified absolute computer-assessed IDO levels as positively correlated with increased risk of death in a multivariate model (HR = 1.02; 95% CI: 1.002-1.04; p = 0.03). In univariate analysis, patients with IDO levels below the median had a better overall survival time (30.3 vs. 17.5 months; p = 0.03). TGF-βR1 and IFN-γR1 expression was modestly correlated (R = 0.34; p lt; 0.05) and TGF-βR1 expression was lower in lymph nodes than in matched primary skin tumors (Z = 2.87; p = 0.004). The pathologists' and computer-aided IHC assessment demonstrated high correlation levels (R = 0.61, R = 0.74 and R = 0.88 for IDO, TGF-βR1 and IFN-γR1, respectively). Indoleamine-2,3-dioxygenase is prognostic for the patient outcome in melanoma with nodal involvement and should be investigated prospectively for its predictive significance. IHC assessment by computer-aided methods is recommended as its gives IHC more objectivity and reproducibility. ecting mismatch repair deficiency. Association of CDX2 and PMS2 in the present study is necessary to conduct further genetic and pathological studies focusing on these two markers together. PMID:27003769

  13. Probing the chemical steps of nitroalkane oxidation catalyzed by 2-nitropropane dioxygenase with solvent viscosity, pH, and substrate kinetic isotope effects.

    Science.gov (United States)

    Francis, Kevin; Gadda, Giovanni

    2006-11-21

    Among the enzymes that catalyze the oxidative denitrification of nitroalkanes to carbonyl compounds, 2-nitropropane dioxygenase is the only one known to effectively utilize both the neutral and anionic (nitronate) forms of the substrate. A recent study has established that the catalytic pathway is common to both types of substrates, except for the initial removal of a proton from the carbon of the neutral substrates [Francis, K., Russell, B., and Gadda, G. (2005) J. Biol. Chem. 280, 5195-5204]. In the present study, the mechanistic properties of the enzyme have been investigated with solvent viscosity, pH, and kinetic isotope effects. With nitroethane or ethylnitronate, the kcat/Km and kcat values were independent of solvent viscosity, consistent with the substrate and product binding to the enzyme in rapid equilibrium. The abstraction of the proton from the alpha carbon of neutral substrates was investigated by measuring the pH dependence of the D(kcat/KNE) value with 1,1-[2H2]-nitroethane. The formation of the enzyme-bound flavosemiquinone formed during catalysis was examined by determining the pH dependence of the kcat/Km values with ethylnitronate and nitroethane and the inhibition by m-nitrobenzoate. Finally, alpha-secondary kinetic isotope effects with 1-[2H]-ethylnitronate were used to propose a non-oxidative tautomerization pathway, in which the enzyme catalyzes the interconversion of nitroalkanes between their anionic and neutral forms. The data presented suggest that enzymatic turnover of 2-nitropropane dioxygenase with neutral substrates is limited by the cleavage of the substrate CH bond at low pH, whereas that with anionic substrates is limited by the non-oxidative tautomerization of ethylnitroante to nitroethane at high pH. PMID:17105207

  14. Crystallization and identification of the glycosylated moieties of two isoforms of the main allergen Hev b 2 and preliminary X-ray analysis of two polymorphs of isoform II

    International Nuclear Information System (INIS)

    Crystallization of important glycoenzymes involved in IgE-mediated latex allergy. Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a β-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content constisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapour-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P41 with unit-cell parameters a = b = 150.17, c = 77.41 Å were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P21, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 Å, β = 113.6°. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units

  15. Crystallization and identification of the glycosylated moieties of two isoforms of the main allergen Hev b 2 and preliminary X-ray analysis of two polymorphs of isoform II

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Silva, D. [Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Mendoza-Hernández, G. [Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Stojanoff, V. [Brookhaven National Laboratory, National Synchrotron Light Source, Upton, NY (United States); Palomares, L. A. [Instituto de Biotecnología, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Zenteno, E. [Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Torres-Larios, A. [Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Rodríguez-Romero, A., E-mail: adela@servidor.unam.mx [Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico)

    2007-09-01

    Crystallization of important glycoenzymes involved in IgE-mediated latex allergy. Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a β-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content constisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapour-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P4{sub 1} with unit-cell parameters a = b = 150.17, c = 77.41 Å were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 Å, β = 113.6°. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units.

  16. Crystallization and Identification of the Glycosylated Moieties of Two Isoforms of the Main Allergen Hev b 2 and Preliminary X-ray Analysis of Two Polymorphs of Isoform ll

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Silva,D.; Mendoza-Hernandez, G.; Stojanoff, V.; Palomares, L.; Zenteno, E.; Torres-Larios, A.; Rodriguez-Romero, A.

    2007-01-01

    Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a {beta}-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content consisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapor-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P4{sub 1} with unit-cell parameters a = b = 150.17, c = 77.41 {angstrom} were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 {angstrom}, {beta}= 113.6{sup o}. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units.

  17. Cloning of a soluble isoform of the SgIGSF adhesion molecule that binds the extracellular domain of the membrane-bound isoform.

    OpenAIRE

    Koma, Yu-ichiro; Ito, Akihiko; Wakayama, Tomohiko; Watabe, Kenji; OKADA, Morihito; Tsubota, Noriaki; Iseki, Shoichi; Kitamura, Yukihiko

    2004-01-01

    SgIGSF (spermatogenic immunoglobulin superfamily) is a recently identified intercellular adhesion molecule of the immunoglobulin superfamily. In a mast-cell cDNA library, we found a clone that resulted from the retention of intron 7 within the mature SgIGSF message. This clone was predicted to encode a soluble isoform of SgIGSF (sSgIGSF) with 336 amino-acid residues because its open reading frame ended just before the transmembrane domain. We constructed a plasmid expressing sSgIGSF fused to ...

  18. Identification of novel chicken estrogen receptor-alpha messenger ribonucleic acid isoforms generated by alternative splicing and promoter usage.

    Science.gov (United States)

    Griffin, C; Flouriot, G; Sonntag-Buck, V; Nestor, P; Gannon, F

    1998-11-01

    Using the rapid amplification of complementary DNA ends (RACE) methodology we have identified three new chicken estrogen receptor-alpha (cER alpha) messenger RNA (mRNA) variants in addition to the previously described form (isoform A). Whereas one of the new variants (isoform B) presents a 5'-extremity contiguous to the 5'-end of isoform A, the two other forms (isoforms C and D) are generated by alternative splicing of upstream exons (C and D) to a common site situated 70 nucleotides upstream of the translation start site in the previously assigned exon 1 (A). The 3'-end of exon 1C has been located at position -1334 upstream of the transcription start site of the A isoform (+1). Whereas the genomic location of exon 1D is unknown, 700 bp 5' to this exon were isolated by genomic walking, and their sequence was determined. The transcription start sites of the cER alpha mRNA isoforms were defined. In transfection experiments, the regions immediately upstream of the A-D cER alpha mRNA isoforms were shown to possess cell-specific promoter activities. Three of these promoters were down-regulated in the presence of estradiol and ER alpha protein. It is concluded, therefore, that the expression of the four different cER alpha mRNA isoforms is under the control of four different promoters. Finally, RT-PCR, S1 nuclease mapping, and primer extension analysis of these different cER alpha mRNA isoforms revealed a differential pattern of expression of the cER alpha gene in chicken tissues. Together, the results suggest that alternative 5'-splicing and promoter usage may be mechanisms used to modulate the levels of expression of the chicken ER alpha gene in a tissue-specific and/or developmental stage-specific manner. PMID:9794473

  19. Conditional expression of CD44 isoforms in lymphoma cells: influence on hyaluronate binding and tumor growth

    International Nuclear Information System (INIS)

    CD44 describes a family of surface proteins consisting of many isoforms due to alternative splice of ten 'variant' exons. Members of this family are involved in various processes including hematopoiesis, lymphocyte activation and homing, limb development, wound healing and tumor progression. Clinically, CD44 has been shown to be a prognostic factor for several human cancers. To answer the question which isoform might be relevant for tumor progression and to gain an insight into the mechanism of its function, I established transfectants of the LB lymphoma cell line in which the expression of four CD44 isoforms, namely CD44v3-10, CD44v4-10, CD44v8-10 and CD44s, was controlled by the Tet-off promoter. In the presence of Doxycycline, the expression was repressed. Removal of Doxycycline switched on expression and the maximal CD44 amount was obtained within two days. The transfectants were characterized regarding their ability to bind to the extracellular matrix component hyaluronate (HA). Overexpression of all four CD44 isoforms conferred the ability to bind HA on LB cells. Other glycosaminoglycans (GAGs) were bound in an isotype-specific fashion. CD44v3-10, CD44v4-10 and CD44v8-10 showed high binding affinity to chondroitin A, B and C, and low affinity to heparin, heparan sulfate and keratan sulfate. CD44s could not bind to these GAGs. Among these three variants, the binding ability of CD44v3-10 was the strongest. CD44 clustering seemed to play a crucial role for HA binding. Both CD44s and CD44v8-10 formed reduction-sensitive complexes in LB cells. The complexes are homooligomers or heterooligomers composed of different isoforms. Cys286 in CD44 transmember domain was not responsible for the formation of reduction-sensitive oligomer or for the enhanced HA binding in LB cell line. Using a conditional dimerization system the requirement of CD44 oligomerization for HA binding was directly demonstrated. The induction of oligomerization increased HA binding. Finally, I

  20. Conditional expression of CD44 isoforms in lymphoma cells: influence on hyaluronate binding and tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Fu, J.

    2002-03-01

    CD44 describes a family of surface proteins consisting of many isoforms due to alternative splice of ten 'variant' exons. Members of this family are involved in various processes including hematopoiesis, lymphocyte activation and homing, limb development, wound healing and tumor progression. Clinically, CD44 has been shown to be a prognostic factor for several human cancers. To answer the question which isoform might be relevant for tumor progression and to gain an insight into the mechanism of its function, I established transfectants of the LB lymphoma cell line in which the expression of four CD44 isoforms, namely CD44v3-10, CD44v4-10, CD44v8-10 and CD44s, was controlled by the Tet-off promoter. In the presence of Doxycycline, the expression was repressed. Removal of Doxycycline switched on expression and the maximal CD44 amount was obtained within two days. The transfectants were characterized regarding their ability to bind to the extracellular matrix component hyaluronate (HA). Overexpression of all four CD44 isoforms conferred the ability to bind HA on LB cells. Other glycosaminoglycans (GAGs) were bound in an isotype-specific fashion. CD44v3-10, CD44v4-10 and CD44v8-10 showed high binding affinity to chondroitin A, B and C, and low affinity to heparin, heparan sulfate and keratan sulfate. CD44s could not bind to these GAGs. Among these three variants, the binding ability of CD44v3-10 was the strongest. CD44 clustering seemed to play a crucial role for HA binding. Both CD44s and CD44v8-10 formed reduction-sensitive complexes in LB cells. The complexes are homooligomers or heterooligomers composed of different isoforms. Cys286 in CD44 transmember domain was not responsible for the formation of reduction-sensitive oligomer or for the enhanced HA binding in LB cell line. Using a conditional dimerization system the requirement of CD44 oligomerization for HA binding was directly demonstrated. The induction of oligomerization increased HA binding

  1. Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements.

    Directory of Open Access Journals (Sweden)

    Carl O Olson

    Full Text Available MeCP2 is a critical epigenetic regulator in brain and its abnormal expression or compromised function leads to a spectrum of neurological disorders including Rett Syndrome and autism. Altered expression of the two MeCP2 isoforms, MeCP2E1 and MeCP2E2 has been implicated in neurological complications. However, expression, regulation and functions of the two isoforms are largely uncharacterized. Previously, we showed the role of MeCP2E1 in neuronal maturation and reported MeCP2E1 as the major protein isoform in the adult mouse brain, embryonic neurons and astrocytes. Recently, we showed that DNA methylation at the regulatory elements (REs within the Mecp2 promoter and intron 1 impact the expression of Mecp2 isoforms in differentiating neural stem cells. This current study is aimed for a comparative analysis of temporal, regional and cell type-specific expression of MeCP2 isoforms in the developing and adult mouse brain. MeCP2E2 displayed a later expression onset than MeCP2E1 during mouse brain development. In the adult female and male brain hippocampus, both MeCP2 isoforms were detected in neurons, astrocytes and oligodendrocytes. Furthermore, MeCP2E1 expression was relatively uniform in different brain regions (olfactory bulb, striatum, cortex, hippocampus, thalamus, brainstem and cerebellum, whereas MeCP2E2 showed differential enrichment in these brain regions. Both MeCP2 isoforms showed relatively similar distribution in these brain regions, except for cerebellum. Lastly, a preferential correlation was observed between DNA methylation at specific CpG dinucleotides within the REs and Mecp2 isoform-specific expression in these brain regions. Taken together, we show that MeCP2 isoforms display differential expression patterns during brain development and in adult mouse brain regions. DNA methylation patterns at the Mecp2 REs may impact this differential expression of Mecp2/MeCP2 isoforms in brain regions. Our results significantly contribute

  2. Influenza A Viruses Control Expression of Proviral Human p53 Isoforms p53β and Δ133p53α

    OpenAIRE

    Terrier, Olivier; Marcel, Virginie; Cartet, Gaëlle; Lane, David P; Lina, Bruno; Rosa-Calatrava, Manuel; Bourdon, Jean-Christophe

    2012-01-01

    Previous studies have described the role of p53 isoforms, including p53β and Δ133p53α, in the modulation of the activity of full-length p53, which regulates cell fate. In the context of influenza virus infection, an interplay between influenza viruses and p53 has been described, with p53 being involved in the antiviral response. However, the role of physiological p53 isoforms has never been explored in this context. Here, we demonstrate that p53 isoforms play a role in influenza A virus infec...

  3. Multiple tissue-specific isoforms of sulfatide activate CD1d-restricted type II NKT cells

    DEFF Research Database (Denmark)

    Blomqvist, Maria; Rhost, Sara; Teneberg, Susann;

    2009-01-01

    relevant isoforms C24:1 and C24:0, major constituents of the myelin sheet of the nervous system, and C16:0, prominent in the pancreatic islet beta-cells. The most potent sulfatide isoform was lysosulfatide (lacking a fatty acid). Shortened fatty acid chain length (C24:1 versus C18:1), or saturation...... isoforms by a CD1d-restricted NKT-cell clone, and suggest that sulfatide, a major component of the myelin sheet and pancreatic beta-cells, is one of several natural ligands for type II CD1d-restricted NKT cells....

  4. The expression of ELK transcription factors in adult DRG: novel isoforms, antisense transcripts and upregulation by nerve damage

    OpenAIRE

    Kerr, Niall; Pintzas, Alexander; Holmes, Fiona; Hobson, Sally-Ann; Pope, Robert; Wallace, Mark; Wasylyk, Christine; Wasylyk, Bohdan; Wynick, David

    2010-01-01

    ELK transcription factors are expressed in brain, but it is unknown whether they are expressed in the peripheral nervous system. We show by RT-PCR that the previously described Elk1, Elk3/Elk3b/Elk3c and Elk4 mRNAs are expressed in adult dorsal root ganglia (DRG), together with the novel alternatively spliced isoforms Elk1b, Elk3d and Elk4c/Elk4d/Elk4e. These isoforms are also expressed in brain, heart, kidney and testis. In contrast to Elk3 protein, the novel Elk3d isoform is cytoplasmic, fa...

  5. Deep Proteomics of Mouse Skeletal Muscle Enables Quantitation of Protein Isoforms, Metabolic Pathways, and Transcription Factors*

    Science.gov (United States)

    Deshmukh, Atul S.; Murgia, Marta; Nagaraj, Nagarjuna; Treebak, Jonas T.; Cox, Jürgen; Mann, Matthias

    2015-01-01

    Skeletal muscle constitutes 40% of individual body mass and plays vital roles in locomotion and whole-body metabolism. Proteomics of skeletal muscle is challenging because of highly abundant contractile proteins that interfere with detection of regulatory proteins. Using a state-of-the art MS workflow and a strategy to map identifications from the C2C12 cell line model to tissues, we identified a total of 10,218 proteins, including skeletal muscle specific transcription factors like myod1 and myogenin and circadian clock proteins. We obtain absolute abundances for proteins expressed in a muscle cell line and skeletal muscle, which should serve as a valuable resource. Quantitation of protein isoforms of glucose uptake signaling pathways and in glucose and lipid metabolic pathways provides a detailed metabolic map of the cell line compared with tissue. This revealed unexpectedly complex regulation of AMP-activated protein kinase and insulin signaling in muscle tissue at the level of enzyme isoforms. PMID:25616865

  6. A crustin isoform from black tiger shrimp, Penaeus monodon exhibits broad spectrum anti-bacterial activity

    Directory of Open Access Journals (Sweden)

    Debashis Banerjee

    2015-11-01

    Full Text Available Crustaceans have a powerful non-specific immune mechanism that responds to pathogen invasion and together with cellular responses, generates powerful humoral factors such as antimicrobial peptides. Crustins are a diverse class of antimicrobial peptides that are expressed by the circulating haemocytes of crustaceans. Several isoforms of this molecule are reported and in this study, one isoform from the black tiger shrimp, Penaeus monodon was cloned and expressed in Escherichia coli SG 13009. The purified recombinant crustin peptide had a molecular weight of 22 kDa and exhibited potent anti-bacterial activity in vitro against several Gram positive and Gram negative bacteria that included pathogens of aquatic animals and humans. The recombinant crustin showed a minimal inhibitory concentration of 0.5 μg ml−1 against the vibrio pathogens of shrimp, which suggests its promise for application in aquaculture.

  7. Signalling by Transforming Growth Factor Beta Isoforms in Wound Healing and Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Richard W.D. Gilbert

    2016-06-01

    Full Text Available Transforming growth factor beta (TGFβ signalling is essential for wound healing, including both non-specific scar formation and tissue-specific regeneration. Specific TGFβ isoforms and downstream mediators of canonical and non-canonical signalling play different roles in each of these processes. Here we review the role of TGFβ signalling during tissue repair, with a particular focus on the prototypic isoforms TGFβ1, TGFβ2, and TGFβ3. We begin by introducing TGFβ signalling and then discuss the role of these growth factors and their key downstream signalling mediators in determining the balance between scar formation and tissue regeneration. Next we discuss examples of the pleiotropic roles of TGFβ ligands during cutaneous wound healing and blastema-mediated regeneration, and how inhibition of the canonical signalling pathway (using small molecule inhibitors blocks regeneration. Finally, we review various TGFβ-targeting therapeutic strategies that hold promise for enhancing tissue repair.

  8. Detection of Diverse and High Molecular Weight Nesprin-1 and Nesprin-2 Isoforms Using Western Blotting.

    Science.gov (United States)

    Carthew, James; Karakesisoglou, Iakowos

    2016-01-01

    Heavily utilized in cell and molecular biology, western blotting is considered a crucial technique for the detection and quantification of proteins within complex mixtures. In particular, the detection of members of the nesprin (nuclear envelope spectrin repeat protein) family has proven difficult to analyze due to their substantial isoform diversity, molecular weight variation, and the sheer size of both nesprin-1 and nesprin-2 giant protein variants (>800 kDa). Nesprin isoforms contain distinct domain signatures, perform differential cytoskeletal associations, occupy different subcellular compartments, and vary in their tissue expression profiles. This structural and functional variance highlights the need to distinguish between the full range of proteins within the nesprin protein family, allowing for greater understanding of their specific roles in cell biology and disease. Herein, we describe a western blotting protocol modified for the detection of low to high molecular weight (50-1000 kDa) nesprin proteins. PMID:27147045

  9. Characterisation of human fibroblasts as keratinocyte feeder layer using p63 isoforms status.

    Science.gov (United States)

    Auxenfans, Céline; Thépot, Amélie; Justin, Virginie; Hautefeuille, Agnès; Shahabeddin, Lili; Damour, Odile; Hainaut, Pierre

    2009-01-01

    Large-scale culture of primary keratinocytes allows the production of large epidermal sheet surfaces for the treatment of extensive skin burns. This method is dependent upon the capacity to establish cultures of proliferating keratinocytes in conditions compatible with their clonal expansion while maintaining their capacity to differentiate into the typical squamous pattern of human epidermis. Feeder layers are critical in this process because the fibroblasts that compose this layer serve as a source of adhesion, growth and differentiation factors. In this report, we have characterise the expression patterns of p63 isoforms in primary keratinocytes cultured on two different feeder layer systems, murine 3T3 and human fibroblasts. We show that with the latter, keratinocytes express a higher ratio of Delta N to TAp63 isoform, in relation with higher clonogenic potential. These results indicate that human fibroblasts represent an adequate feeder layer system to support the culture of primary human keratinocytes. PMID:20042803

  10. Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL) isoforms

    DEFF Research Database (Denmark)

    Krintel, Christian; Klint, Cecilia; Lindvall, Håkan;

    2010-01-01

    Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa) expressed in a tissue-dependen......Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa) expressed in a tissue...

  11. Metabolism of 7-benzyloxy-4-trifluoromethyl-coumarin by human hepatic cytochrome P450 isoforms.

    Science.gov (United States)

    Renwick, A B; Surry, D; Price, R J; Lake, B G; Evans, D C

    2000-10-01

    1. The metabolism of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) to 7-hydroxy-4-trifluoromethylcoumarin (HFC) was studied in human liver microsomal preparations and in cDNA-expressed human cytochrome P450 (CYP) isoforms. 2. Kinetic analysis of the NADPH-dependent metabolism of BFC to HFC in four preparations of pooled human liver microsomes revealed mean (+/- SEM) Km and Vmax of 8.3 +/- 1.3 microM and 454 +/- 98 pmol/min/mg protein respectively. 3. The metabolism of BFC to HFC was determined in a characterized bank of 24 individual human liver microsomal preparations employing BFC substrate concentrations of 20 and 50 microM (i.e. about two and six times Km respectively). With 20 microM BFC the highest correlations were observed between BFC metabolism and markers of CYP1A2 (r2 = 0.784-0.797) and then with CYP3A (r2 = 0.434-0.547) isoforms, whereas with 50 microM BFC the highest correlations were observed between BFC metabolism and markers of CYP3A (r2 = 0.679-0.837) and then with CYP1A2 (r2 = 0.421-0.427) isoforms. At both BFC substrate concentrations, lower correlations were observed between BFC metabolism and enzymatic markers for CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP4A9/11. 4. Using human beta-lymphoblastoid cell microsomes containing cDNA-expressed CYP isoforms, 20 microM BFC was metabolized by CYP1A2 and CYP3A4, with lower rates of metabolism being observed with CYP2C9 and CYP2C19. Kinetic studies with the CYP1A2 and CYP3A4 preparations demonstrated a lower Km with the CYP1A2 preparation, but a higher Vmax with the CYP3A4 preparation. 5. The metabolism of 20 microM BFC in human liver microsomes was inhibited to 37-48% of control by 5-100 microM of the mechanism-based CYP1A2 inhibitor furafylline and to 64-69% of control by 5-100 microM of the mechanism-based CYP3A4 inhibitor troleandomycin. While some inhibition of BFC metabolism was observed in the presence of 100 and 200 microM diethyldithiocarbamate, the addition of 2-50 micro

  12. Algal Toxin Azaspiracid-1 Induces Early Neuronal Differentiation and Alters Peripherin Isoform Stoichiometry

    Directory of Open Access Journals (Sweden)

    Linda V. Hjørnevik

    2015-12-01

    Full Text Available Azaspiracid-1 is an algal toxin that accumulates in edible mussels, and ingestion may result in human illness as manifested by vomiting and diarrhoea. When injected into mice, it causes neurotoxicological symptoms and death. Although it is well known that azaspiracid-1 is toxic to most cells and cell lines, little is known about its biological target(s. A rat PC12 cell line, commonly used as a model for the peripheral nervous system, was used to study the neurotoxicological effects of azaspiracid-1. Azaspiracid-1 induced differentiation-related morphological changes followed by a latter cell death. The differentiated phenotype showed peripherin-labelled neurite-like processes simultaneously as a specific isoform of peripherin was down-regulated. The precise mechanism behind this down-regulation remains uncertain. However, this study provides new insights into the neurological effects of azaspiracid-1 and into the biological significance of specific isoforms of peripherin.

  13. Alternatively spliced short and long isoforms of adaptor protein intersectin 1 form complexes in mammalian cells

    Directory of Open Access Journals (Sweden)

    Rynditch A. V.

    2012-12-01

    Full Text Available Intersectin 1 (ITSN1 is an adaptor protein involved in membrane trafficking and cell signaling. Long and short isoforms of ITSN1 (ITSN1-L and ITSN1-S are produced by alternative splicing. The aim of our study was to investigate whether ITSN1-L and ITSN1-S could interact in mammalian cells. Methods. During this study we employed immunoprecipitation and confocal microscopy. Results. We have shown that endogenous ITSN1-S co-precipitates with overexpressed ITSN1-L in PC12, 293 and 293T cells. Long and short isoforms of ITSN1 also co-localize in 293T cells. Conclusions. ITSN1-L and ITSN1-S form complexes in mammalian cells.

  14. Design and Synthesis of Simplified Largazole Analogues as Isoform-Selective Human Lysine Deacetylase Inhibitors.

    Science.gov (United States)

    Reddy, Damodara N; Ballante, Flavio; Chuang, Timothy; Pirolli, Adele; Marrocco, Biagina; Marshall, Garland R

    2016-02-25

    Selective inhibition of KDAC isoforms while maintaining potency remains a challenge. Using the largazole macrocyclic depsipeptide structure as a starting point for developing new KDACIs with increased selectivity, a combination of four different simplified largazole analogue (SLA) scaffolds with diverse zinc-binding groups (for a total of 60 compounds) were designed, synthesized, and evaluated against class I KDACs 1, 3, and 8, and class II KDAC6. Experimental evidence as well as molecular docking poses converged to establish the cyclic tetrapeptides (CTPs) as the primary determinant of both potency and selectivity by influencing the correct alignment of the zinc-binding group in the KDAC active site, providing a further basis for developing new KDACIs of higher isoform selectivity and potency. PMID:26681404

  15. Hemoglobin isoform differentiation and allosteric regulation of oxygen binding in the turtle, Trachemys scripta

    DEFF Research Database (Denmark)

    Damsgaard, Christian; Storz, Jay F.; Hoffmann, Federico G.;

    2013-01-01

    When freshwater turtles acclimatize to winter hibernation, there is a gradual transition from aerobic to anaerobic metabolism, which may require adjustments of blood O2 transport before turtles become anoxic. Here, we report the effects of protons, anionic cofactors, and temperature on the O2......-binding properties of isolated hemoglobin (Hb) isoforms, HbA and HbD, in the turtle Trachemys scripta. We determined the primary structures of the constituent subunits of the two Hb isoforms, and we related the measured functional properties to differences in O2 affinity between untreated hemolysates from...... turtles that were acclimated to normoxia and anoxia. Our data show that HbD has a consistently higher O2 affinity compared with HbA, whereas Bohr and temperature effects, as well as thiol reactivity, are similar. Although sequence data show amino acid substitutions at two known β-chain ATP-binding site...

  16. Isoforms of agrin are widely expressed in the developing rat and may function as protease inhibitors.

    Science.gov (United States)

    Biroc, S L; Payan, D G; Fisher, J M

    1993-09-17

    The agrin family of extracellular matrix proteins may be important in the formation of the neuromuscular junction. Using in situ hybridization with a probe recognizing all agrin isoforms, we demonstrate that it is widely expressed during mammalian embryogenesis. In the developing rat, particularly high levels of expression are found in the dorsal root and cranial ganglia, gut, whisker rudiments, penis, snout, teeth, retina, hippocampus, cerebral cortex and the lining of brain ventricles. Functional analysis of the recombinant rat protein shows that it is a potent inhibitor of the proteases trypsin, chymotrypsin and plasmin but not thrombin or the plasminogen activators. We conclude that agrin and its isoforms may play multiple roles in mammalian development including the regulation of proteolysis in the extracellular matrix.

  17. Effects of eugenol on T-type Ca2+ channel isoforms.

    Science.gov (United States)

    Seo, Haengsoo; Li, Hai Ying; Perez-Reyes, Edward; Lee, Jung-Ha

    2013-11-01

    Eugenol has been used as an analgesic in dentistry. Previous studies have demonstrated that voltage-gated Na(+) channels and high-voltage-activated Ca(2+) channels expressed in trigeminal ganglion (TG) neurons sensing dental pain are molecular targets of eugenol for its analgesic effects. However, it has not been investigated whether eugenol can affect T-type Ca(2+) channels, which are known to be detected in the afferent neurons. In this report, we investigate how eugenol can influence cloned T-type channel isoforms expressed in HEK293 cells, using whole-cell patch clamp. Application of eugenol inhibited Cav3.1, Cav3.2, and Cav3.3 currents in a concentration-dependent manner with IC50 values of 463, 486, and 708 μM, respectively. Eugenol was found to negatively shift the steady-state inactivation curves of the T-type channel isoforms, but it did not shift their activation curves. In addition, eugenol had little effect on the current kinetics of Cav3.1 and Cav3.2, but it accelerated the inactivation kinetics of Cav3.3 currents. Reduction of channel availability enhanced eugenol inhibition sensitivity for Cav3.1 and Cav3.2, but not for Cav3.3. Moreover, eugenol inhibition of T-type channel isoforms was found to be use dependent. Finally, we show that the T-type currents recorded from rat TG neurons were inhibited by eugenol with a similar potency to Cav3.1 and Cav3.2 isoforms. Taken together, our findings suggest that T-type Ca(2+) channels are additional molecular targets for the pain-relieving effects of eugenol.

  18. PSD-95 mediates membrane clustering of the human plasma membrane Ca2+ pump isoform 4b

    OpenAIRE

    Padányi, Rita; Pászty, Katalin; STREHLER, EMANUEL E.; Enyedi, Ágnes

    2008-01-01

    Besides the control of global calcium changes, specific plasma membrane calcium ATPase (PMCA) isoforms are involved in the regulation of local calcium signals. Although local calcium signaling requires the confinement of signaling molecules into microdomains, little is known about the specific organization of PMCA molecules within the plasma membrane. Here we show that co-expression with the postsynaptic–density-95 (PSD-95) scaffolding protein increased the plasma membrane expression of PMCA4...

  19. Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform.

    Directory of Open Access Journals (Sweden)

    Coby M M Laarakkers

    Full Text Available Mass spectrometry (MS-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25(+40 isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF platforms. As expected, implementation of hepcidin-25(+40 as internal standard in our weak cation exchange (WCX TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9 with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and

  20. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    International Nuclear Information System (INIS)

    The nuclear receptor farnesoid X receptor alpha (FXRα, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxrα in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXRα (∼70% in the ligand-binding domain). Fxrα1 and Fxrα2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process results in Fxrα1 having an extended N-terminus compared to Fxrα2. A Gal4DBD-FxrαLBD fusion construct was activated by chenodeoxycholic, cholic, deoxycholic and lithocholic acids, and the synthetic agonist GW4064 in transient transactivation assays. Activation of the Gal4DBD-FxrαLBD fusion construct was enhanced by addition of PGC-1α, as demonstrated through titration assays. Surprisingly, when the full-length versions of the two Fxrα isoforms were compared in transient transfection assays, Fxrα2 was activated by C24 bile acids and GW4064, while Fxrα1 was not significantly activated by any of the compounds tested. Since the only significant difference between the full-length constructs was sequence in the AF1 domain, these experiments highlight a key functional region in the Fxrα AF1 domain. Furthermore, mammalian two-hybrid studies demonstrated the ability of Fxrα2, but not Fxrα1, to interact with PGC-1α and SRC-1, and supported our results from the transient transfection reporter gene activation assays. These data demonstrate that both mammalian and teleost FXR (Fxrα2 isoform) are activated by primary and secondary bile acids.

  1. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Howarth, Deanna L. [Integrated Toxicology and Environmental Health Program and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708 (United States); Hagey, Lee R. [Department of Medicine, University of California at San Diego, La Jolla, CA 92093 (United States); Law, Sheran H.W. [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States); Ai, Ni [Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854 (United States); Krasowski, Matthew D. [Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Ekins, Sean [Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854 (United States); Collaboration in Chemistry, Jenkintown, PA 19046 (United States); Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201 (United States); Moore, John T. [GlaxoSmithKline Discovery Research, Research Triangle Park, NC 27709 (United States); Kollitz, Erin M. [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States); Hinton, David E. [Integrated Toxicology and Environmental Health Program and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708 (United States); Kullman, Seth W., E-mail: swkullma@ncsu.edu [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States)

    2010-07-01

    The nuclear receptor farnesoid X receptor alpha (FXR{alpha}, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxr{alpha} in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXR{alpha} ({approx}70% in the ligand-binding domain). Fxr{alpha}1 and Fxr{alpha}2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process results in Fxr{alpha}1 having an extended N-terminus compared to Fxr{alpha}2. A Gal4DBD-Fxr{alpha}LBD fusion construct was activated by chenodeoxycholic, cholic, deoxycholic and lithocholic acids, and the synthetic agonist GW4064 in transient transactivation assays. Activation of the Gal4DBD-Fxr{alpha}LBD fusion construct was enhanced by addition of PGC-1{alpha}, as demonstrated through titration assays. Surprisingly, when the full-length versions of the two Fxr{alpha} isoforms were compared in transient transfection assays, Fxr{alpha}2 was activated by C{sub 24} bile acids and GW4064, while Fxr{alpha}1 was not significantly activated by any of the compounds tested. Since the only significant difference between the full-length constructs was sequence in the AF1 domain, these experiments highlight a key functional region in the Fxr{alpha} AF1 domain. Furthermore, mammalian two-hybrid studies demonstrated the ability of Fxr{alpha}2, but not Fxr{alpha}1, to interact with PGC-1{alpha} and SRC-1, and supported our results from the transient transfection reporter gene activation assays. These data demonstrate that both mammalian and teleost FXR (Fxr{alpha}2 isoform) are activated by primary and secondary bile acids.

  2. iReckon: Simultaneous isoform discovery and abundance estimation from RNA-seq data

    OpenAIRE

    Mezlini, Aziz M.; Smith, Eric J. M.; Fiume, Marc; Buske, Orion; Savich, Gleb L.; Shah, Sohrab; Aparicio, Sam; Chiang, Derek Y.; Goldenberg, Anna; Brudno, Michael

    2013-01-01

    High-throughput RNA sequencing (RNA-seq) promises to revolutionize our understanding of genes and their role in human disease by characterizing the RNA content of tissues and cells. The realization of this promise, however, is conditional on the development of effective computational methods for the identification and quantification of transcripts from incomplete and noisy data. In this article, we introduce iReckon, a method for simultaneous determination of the isoforms and estimation of th...

  3. Revealing the functions of the transketolase enzyme isoforms in Rhodopseudomonas palustris using a systems biology approach.

    Directory of Open Access Journals (Sweden)

    Chia-Wei Hu

    Full Text Available BACKGROUND: Rhodopseudomonas palustris (R. palustris is a purple non-sulfur anoxygenic phototrophic bacterium that belongs to the class of proteobacteria. It is capable of absorbing atmospheric carbon dioxide and converting it to biomass via the process of photosynthesis and the Calvin-Benson-Bassham (CBB cycle. Transketolase is a key enzyme involved in the CBB cycle. Here, we reveal the functions of transketolase isoforms I and II in R. palustris using a systems biology approach. METHODOLOGY/PRINCIPAL FINDINGS: By measuring growth ability, we found that transketolase could enhance the autotrophic growth and biomass production of R. palustris. Microarray and real-time quantitative PCR revealed that transketolase isoforms I and II were involved in different carbon metabolic pathways. In addition, immunogold staining demonstrated that the two transketolase isoforms had different spatial localizations: transketolase I was primarily associated with the intracytoplasmic membrane (ICM but transketolase II was mostly distributed in the cytoplasm. Comparative proteomic analysis and network construction of transketolase over-expression and negative control (NC strains revealed that protein folding, transcriptional regulation, amino acid transport and CBB cycle-associated carbon metabolism were enriched in the transketolase I over-expressed strain. In contrast, ATP synthesis, carbohydrate transport, glycolysis-associated carbon metabolism and CBB cycle-associated carbon metabolism were enriched in the transketolase II over-expressed strain. Furthermore, ATP synthesis assays showed a significant increase in ATP synthesis in the transketolase II over-expressed strain. A PEPCK activity assay showed that PEPCK activity was higher in transketolase over-expressed strains than in the negative control strain. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that the two isoforms of transketolase in R. palustris could affect photoautotrophic growth

  4. Characterization of Alien isoforms in vertebrates : Caracterización de isoformas de Alien en vertebrados

    OpenAIRE

    Tenbaum, Stephan

    2002-01-01

    Alien protein isoforms have been described to be involved in a number of biological processes. Alienalpha is a corepressor of the thyroid hormone receptor mediating transcriptional repression in a ligand-sensitive manner. Furthermore, Alienalpha is a corepressor for the orphan receptor DAX1 and the vitamin-D3 receptor. Alienbetta/CSN2 is part of the COP9-signalosome complex that acts in protein phosphorylation, protein degradation and cell cycle regulation. The major goal of this...

  5. Decreased Levels of the Gelsolin Plasma Isoform in Patients with Rheumatoid Arthritis

    OpenAIRE

    Osborn, Teresia M.; Verdrengh, Margareta; Stossel, Thomas Peter; Tarkowski, Andrej; Bokarewa, Maria

    2008-01-01

    Introduction Gelsolin is an intracellular actin-binding protein involved in cell shape changes, cell motility, and apoptosis. An extracellular gelsolin isoform, plasma gelsolin circulates in the blood of healthy individuals at a concentration of \\(200 \\pm 50\\) mg/L and has been suggested to be a key component of an extracellular actin-scavenging system during tissue damage. Levels of plasma gelsolin decrease during acute injury and inflammation, and administration of recombinant plasma gelsol...

  6. New isoforms and assembly of glutamine synthetase in the leaf of wheat (Triticum aestivum L.).

    Science.gov (United States)

    Wang, Xiaochun; Wei, Yihao; Shi, Lanxin; Ma, Xinming; Theg, Steven M

    2015-11-01

    Glutamine synthetase (GS; EC 6.3.1.2) plays a crucial role in the assimilation and re-assimilation of ammonia derived from a wide variety of metabolic processes during plant growth and development. Here, three developmentally regulated isoforms of GS holoenzyme in the leaf of wheat (Triticum aestivum L.) seedlings are described using native-PAGE with a transferase activity assay. The isoforms showed different mobilities in gels, with GSII>GSIII>GSI. The cytosolic GSI was composed of three subunits, GS1, GSr1, and GSr2, with the same molecular weight (39.2kDa), but different pI values. GSI appeared at leaf emergence and was active throughout the leaf lifespan. GSII and GSIII, both located in the chloroplast, were each composed of a single 42.1kDa subunit with different pI values. GSII was active mainly in green leaves, while GSIII showed brief but higher activity in green leaves grown under field conditions. LC-MS/MS experiments revealed that GSII and GSIII have the same amino acid sequence, but GSII has more modification sites. With a modified blue native electrophoresis (BNE) technique and in-gel catalytic activity analysis, only two GS isoforms were observed: one cytosolic and one chloroplastic. Mass calibrations on BNE gels showed that the cytosolic GS1 holoenzyme was ~490kDa and likely a dodecamer, and the chloroplastic GS2 holoenzyme was ~240kDa and likely a hexamer. Our experimental data suggest that the activity of GS isoforms in wheat is regulated by subcellular localization, assembly, and modification to achieve their roles during plant development.

  7. Prokaryotic expression and characterization of a pea actin isoform (PEAcl) fused to GFP

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shaobin; REN Dongtao; XU Xiaojing; LIU Guoqin

    2004-01-01

    Actins widely exist in eukaryotic cells and play important roles in many living activities. As there are many kinds of actin isoforms in plant cells, it is difficult to purify each actin isoform in sufficient quantities for analyzing its physicochemical properties. In the present study, a pea(Pisum Sativum L.) actin isoform (PEAc1) fused to His-tag at its amino terminus and GFP (green fluorescent protein) at its Carboxyl terminus were expressed in E. Coli in inclusion bodies. The fusion protein (PEAc1-GFP) was highly purified with the yield of above 2 mg/L culture by dissolving inclusions in 8 mol/L urea, renaturing by dialysis in a gradient of urea, and affinity binding to Ni-resin. The purified mono meric PEAc1-GFP could efficiently bind on Dnase Ⅰ and inhibit the latter's enzyme activity. PEAc1-GFP could polymerize into green fluorescent filamentous structures (F-PEAc1-GFP), which could be labeled by TRITC-phalloidin, a specific agent for observing microfilaments. The PEAc1-GFP polymerization curve was identical with that of chicken skeletal muscle actin. The critical concentration for PEAc1-GFP to polymerize into filaments is 0.24 μmol/L. The F-PEAc1-GFP could stimulate myosin Mg-ATPase activity in a protein concentration dependant manner (about 4 folds at1 mg/mL F-PEAc1-GFP). The results above show that the PEAcl fused to GFP retained the assembly characteristic of actin, indicating that gene fusion, prokaryotic expression,denaturation and renaturation, and affinity chromatography is a useful strategy for obtaining plant actin isoform proteins in a large amount.

  8. Functional demonstrations of starch binding domains present in Ostreococcus tauri starch synthases isoforms

    OpenAIRE

    Barchiesi, Julieta; Hedin, Nicolás; Gomez-Casati, Diego F.; Miguel A Ballicora; Busi, María V.

    2015-01-01

    Background Starch-binding domains are key modules present in several enzymes involved in polysaccharide metabolism. These non-catalytic modules have already been described as essential for starch-binding and the catalytic activity of starch synthase III from the higher plant Arabidopsis thaliana. In Ostreococcus tauri, a unicellular green alga of the Prasinophyceae family, there are three SSIII isoforms, known as Ostta SSIII-A, SSIII-B and SSIII-C. Results In this work, using in silico and in...

  9. Cell elasticity is regulated by the tropomyosin isoform composition of the actin cytoskeleton.

    Science.gov (United States)

    Jalilian, Iman; Heu, Celine; Cheng, Hong; Freittag, Hannah; Desouza, Melissa; Stehn, Justine R; Bryce, Nicole S; Whan, Renee M; Hardeman, Edna C; Fath, Thomas; Schevzov, Galina; Gunning, Peter W

    2015-01-01

    The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.

  10. Formation of VEGF isoform-specific spatial distributions governing angiogenesis: computational analysis

    Directory of Open Access Journals (Sweden)

    Mac Gabhann Feilim

    2011-05-01

    Full Text Available Abstract Background The spatial distribution of vascular endothelial growth factor A (VEGF is an important mediator of vascular patterning. Previous experimental studies in the mouse hindbrain and retina have suggested that VEGF alternative splicing, which controls the ability of VEGF to bind to heparan sulfate proteoglycans (HSPGs in the extracellular matrix (ECM, plays a key role in controlling VEGF diffusion and gradients in tissues. Conversely, proteolysis notably by matrix metalloproteinases (MMPs, plays a critical role in pathological situations by releasing matrix-sequestered VEGF and modulating angiogenesis. However, computational models have predicted that HSPG binding alone does not affect VEGF localization or gradients at steady state. Results Using a 3D molecular-detailed reaction-diffusion model of VEGF ligand-receptor kinetics and transport, we test alternate models of VEGF transport in the extracellular environment surrounding an endothelial sprout. We show that differences in localization between VEGF isoforms, as observed experimentally in the mouse hindbrain, as well as the ability of proteases to redistribute VEGF in pathological situations, are consistent with a model where VEGF is endogenously cleared or degraded in an isoform-specific manner. We use our predictions of the VEGF distribution to quantify a tip cell's receptor binding and gradient sensing capacity. A novel prediction is that neuropilin-1, despite functioning as a coreceptor to VEGF165-VEGFR2 binding, reduces the ability of a cell to gauge the relative steepness of the VEGF distribution. Comparing our model to available in vivo vascular patterning data suggests that vascular phenotypes are most consistently predicted at short range by the soluble fraction of the VEGF distributions, or at longer range by matrix-bound VEGF detected in a filopodia-dependent manner. Conclusions Isoform-specific VEGF degradation provides a possible explanation for numerous examples

  11. VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

    International Nuclear Information System (INIS)

    Highlights: •We discovered a new member of VEGFxxxb family-VEGF111b. •We found VEGF111b mRNA and protein can be induced by mitomycin C. •We confirmed VEGF111b over-expression inhibits angiogenesis. •VEGF111b inhibits angiogenesis through inhibiting VEGF-R2/PI3K/Akt and VEGF-R2/ERK1/2 phosphorylation. -- Abstract: Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA3.1 empty vector, pcDNA3.1-VEGF111b or pcDNA3.1-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth

  12. PPARγ isoforms differentially regulate metabolic networks to mediate mouse prostatic epithelial differentiation

    OpenAIRE

    Strand, D.W.; Jiang, M; Murphy, T A; Yi, Y.; Konvinse, K C; Franco, O E; Wang, Y.; Young, J D; Hayward, S.W.

    2012-01-01

    Recent observations indicate prostatic diseases are comorbidities of systemic metabolic dysfunction. These discoveries revealed fundamental questions regarding the nature of prostate metabolism. We previously showed that prostate-specific ablation of PPARγ in mice resulted in tumorigenesis and active autophagy. Here, we demonstrate control of overlapping and distinct aspects of prostate epithelial metabolism by ectopic expression of individual PPARγ isoforms in PPARγ knockout prostate epithel...

  13. Characterization of fusion genes and the significantly expressed fusion isoforms in breast cancer by hybrid sequencing

    OpenAIRE

    Weirather, Jason L.; Afshar, Pegah Tootoonchi; Clark, Tyson A.; Tseng, Elizabeth; Powers, Linda S.; Underwood, Jason G; Zabner, Joseph; Korlach, Jonas; Wong, Wing Hung; Au, Kin Fai

    2015-01-01

    We developed an innovative hybrid sequencing approach, IDP-fusion, to detect fusion genes, determine fusion sites and identify and quantify fusion isoforms. IDP-fusion is the first method to study gene fusion events by integrating Third Generation Sequencing long reads and Second Generation Sequencing short reads. We applied IDP-fusion to PacBio data and Illumina data from the MCF-7 breast cancer cells. Compared with the existing tools, IDP-fusion detects fusion genes at higher precision and ...

  14. Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

    Science.gov (United States)

    Eilers, Wouter; Gevers, Wouter; van Overbeek, Daniëlle; de Haan, Arnold; Jaspers, Richard T.; Hilbers, Peter A.; van Riel, Natal; Flück, Martin

    2014-01-01

    We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII) contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE) coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis) and slow-type muscle (soleus) for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02). In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII. PMID:25054156

  15. Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

    Directory of Open Access Journals (Sweden)

    Wouter Eilers

    2014-01-01

    Full Text Available We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis and slow-type muscle (soleus for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02. In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII.

  16. SASD: the Synthetic Alternative Splicing Database for identifying novel isoform from proteomics

    OpenAIRE

    Zhang, Fan; Drabier, Renee

    2013-01-01

    Background Alternative splicing is an important and widespread mechanism for generating protein diversity and regulating protein expression. High-throughput identification and analysis of alternative splicing in the protein level has more advantages than in the mRNA level. The combination of alternative splicing database and tandem mass spectrometry provides a powerful technique for identification, analysis and characterization of potential novel alternative splicing protein isoforms from pro...

  17. Isoform-specific anti-MeCP2 antibodies confirm that expression of the e1 isoform strongly predominates in the brain [v1; ref status: indexed, http://f1000r.es/1mg

    Directory of Open Access Journals (Sweden)

    Lara Kaddoum

    2013-10-01

    Full Text Available Rett syndrome is a neurological disorder caused by mutations in the MECP2 gene.  MeCP2 transcripts are alternatively spliced to generate two protein isoforms (MeCP2_e1 and MeCP2_e2 that differ at their N-termini. Whilst mRNAs for both forms are expressed ubiquitously, the one for MeCP2_e1 is more abundant than for MeCP2_e2 in the central nervous system. In transfected cells, both protein isoforms are nuclear and colocalize with densely methylated heterochromatic foci. With a view to understanding the physiological contribution of each isoform, and their respective roles in the pathogenesis of Rett syndrome, we set out to generate isoform-specific anti-MeCP2 antibodies. To this end, we immunized rabbits against the peptides corresponding to the short amino-terminal portions that are different between the two isoforms. The polyclonal antibodies thus obtained specifically detected their respective isoforms of MeCP2 in Neuro2a (N2A cells transfected to express either form. Both antisera showed comparable sensitivities when used for Western blot or immunofluorescence, and were highly specific for their respective isoform. When those antibodies were used on mouse tissues, specific signals were easily detected for Mecp2_e1, whilst Mecp2_e2 was very difficult to detect by Western blot, and even more so by immunofluorescence. Our results thus suggest that brain cells express low amounts of the Mecp2-e2 isoform. Our findings are compatible with recent reports showing that MeCP2_e2 is dispensable for healthy brain function, and that it may be involved in the regulation of neuronal apoptosis and embryonic development.

  18. Alternative Splicing Generates Different Parkin Protein Isoforms: Evidences in Human, Rat, and Mouse Brain

    Directory of Open Access Journals (Sweden)

    Soraya Scuderi

    2014-01-01

    Full Text Available Parkinson protein 2, E3 ubiquitin protein ligase (PARK2 gene mutations are the most frequent causes of autosomal recessive early onset Parkinson’s disease and juvenile Parkinson disease. Parkin deficiency has also been linked to other human pathologies, for example, sporadic Parkinson disease, Alzheimer disease, autism, and cancer. PARK2 primary transcript undergoes an extensive alternative splicing, which enhances transcriptomic diversification. To date several PARK2 splice variants have been identified; however, the expression and distribution of parkin isoforms have not been deeply investigated yet. Here, the currently known PARK2 gene transcripts and relative predicted encoded proteins in human, rat, and mouse are reviewed. By analyzing the literature, we highlight the existing data showing the presence of multiple parkin isoforms in the brain. Their expression emerges from conflicting results regarding the electrophoretic mobility of the protein, but it is also assumed from discrepant observations on the cellular and tissue distribution of parkin. Although the characterization of each predicted isoforms is complex, since they often diverge only for few amino acids, analysis of their expression patterns in the brain might account for the different pathogenetic effects linked to PARK2 gene mutations.

  19. Isoform-specific regulation and localization of the coxsackie and adenovirus receptor in human airway epithelia.

    Directory of Open Access Journals (Sweden)

    Katherine J D A Excoffon

    Full Text Available Adenovirus is an important respiratory pathogen. Adenovirus fiber from most serotypes co-opts the Coxsackie-Adenovirus Receptor (CAR to bind and enter cells. However, CAR is a cell adhesion molecule localized on the basolateral membrane of polarized epithelia. Separation from the lumen of the airways by tight junctions renders airway epithelia resistant to inhaled adenovirus infection. Although a role for CAR in viral spread and egress has been established, the mechanism of initial respiratory infection remains controversial. CAR exists in several protein isoforms including two transmembrane isoforms that differ only at the carboxy-terminus (CAR(Ex7 and CAR(Ex8. We found low-level expression of the CAR(Ex8 isoform in well-differentiated human airway epithelia. Surprisingly, in contrast to CAR(Ex7, CAR(Ex8 localizes to the apical membrane of epithelia where it augments adenovirus infection. Interestingly, despite sharing a similar class of PDZ-binding domain with CAR(Ex7, CAR(Ex8 differentially interacts with PICK1, PSD-95, and MAGI-1b. MAGI-1b appears to stoichiometrically regulate the degradation of CAR(Ex8 providing a potential mechanism for the apical localization of CAR(Ex8 in airway epithelial. In summary, apical localization of CAR(Ex8 may be responsible for initiation of respiratory adenoviral infections and this localization appears to be regulated by interactions with PDZ-domain containing proteins.

  20. Effect of silencing the two major tomato fruit pectin methylesterase isoforms on cell wall pectin metabolism.

    Science.gov (United States)

    Wen, B; Ström, A; Tasker, A; West, G; Tucker, G A

    2013-11-01

    Post-harvest storage is largely limited by fruit softening, a result of cell wall degradation. Pectin methylesterase (PE) (EC 3.1.1.11) is a major hydrolase responsible for pectin de-esterification in the cell wall, a response to fruit ripening. Two major PE isoforms, PE1 and PE2, have been isolated from tomato (Solanum lycopersicon) pericarp tissue and both have previously been down-regulated using antisense suppression. In this paper, PE1 and PE2 double antisense tomato plants were successfully generated through crossing the two single antisense lines. In the double antisense fruit, approximately 10% of normal PE activity remained and ripening associated pectin de-esterification was almost completely blocked. However, double antisense fruit softened normally during ripening. In tomato fruit, the PE1 isoform was found to contribute little to total PE activity and have little effect on the degree of esterification of pectin. In contrast, the other dominant fruit isoform, PE2, has a major impact on de-esterification of total pectin. PE2 appears to act on non-CDTA-soluble pectin during ripening and on CDTA-soluble pectin before the start of ripening in a potentially block-wise fashion.

  1. Probing polypeptide GalNAc-transferase isoform substrate specificities by in vitro analysis.

    Science.gov (United States)

    Kong, Yun; Joshi, Hiren J; Schjoldager, Katrine Ter-Borch Gram; Madsen, Thomas Daugbjerg; Gerken, Thomas A; Vester-Christensen, Malene B; Wandall, Hans H; Bennett, Eric Paul; Levery, Steven B; Vakhrushev, Sergey Y; Clausen, Henrik

    2015-01-01

    N-acetylgalactosaminyltransferase (GalNAc)-type (mucin-type) O-glycosylation is an abundant and highly diverse modification of proteins. This type of O-glycosylation is initiated in the Golgi by a large family of up to 20 homologous polypeptide GalNAc-T isoenzymes that transfer GalNAc to Ser, Thr and possibly Tyr residues. These GalNAc residues are then further elongated by a large set of glycosyltransferases to build a variety of complex O-glycan structures. What determines O-glycan site occupancy is still poorly understood, although it is clear that the substrate specificities of individual isoenzymes and the repertoire of GalNAc-Ts in cells are key parameters. The GalNAc-T isoenzymes are differentially expressed in cells and tissues in principle allowing cells to produce unique O-glycoproteomes dependent on the specific subset of isoforms present. In vitro analysis of acceptor peptide substrate specificities using recombinant expressed GalNAc-Ts has been the method of choice for probing activities of individual isoforms, but these studies have been hampered by biological validation of actual O-glycosylation sites in proteins and number of substrate testable. Here, we present a systematic analysis of the activity of 10 human GalNAc-T isoenzymes with 195 peptide substrates covering known O-glycosylation sites and provide a comprehensive dataset for evaluating isoform-specific contributions to the O-glycoproteome.

  2. Peroxiredoxin isoforms are associated with cardiovascular risk factors in type 2 diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    El Eter, E. [Physiology Department, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Cardiovascular Research Group, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Physiology Department, Faculty of Medicine, Alexandria University, Alexandria (Egypt); Al-Masri, A.A. [Physiology Department, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Cardiovascular Research Group, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia)

    2015-03-03

    The production of oxygen free radicals in type 2 diabetes mellitus contributes to the development of complications, especially the cardiovascular-related ones. Peroxiredoxins (PRDXs) are antioxidant enzymes that combat oxidative stress. The aim of this study was to investigate the associations between the levels of PRDX isoforms (1, 2, 4, and 6) and cardiovascular risk factors in type 2 diabetes mellitus. Fifty-three patients with type 2 diabetes mellitus (28F/25M) and 25 healthy control subjects (7F/18M) were enrolled. We measured the plasma levels of each PRDX isoform and analyzed their correlations with cardiovascular risk factors. The plasma PRDX1, -2, -4, and -6 levels were higher in the diabetic patients than in the healthy control subjects. PRDX2 and -6 levels were negatively correlated with diastolic blood pressure, fasting blood sugar, and hemoglobin A1c. In contrast, PRDX1 levels were positively correlated with low-density lipoprotein and C-reactive protein levels. PRDX4 levels were negatively correlated with triglycerides. In conclusion, PRDX1, -2, -4, and -6 showed differential correlations with a variety of traditional cardiovascular risk factors. These results should encourage further research into the crosstalk between PRDX isoforms and cardiovascular risk factors.

  3. Energy-optimised pharmacophore approach to identify potential hotspots during inhibition of Class II HDAC isoforms.

    Science.gov (United States)

    Ganai, Shabir Ahmad; Shanmugam, Karthi; Mahadevan, Vijayalakshmi

    2015-01-01

    Histone deacetylases (HDACs) are conjugated enzymes that modulate chromatin architecture by deacetylating lysine residues on the histone tails leading to transcriptional repression. Pharmacological interventions of these enzymes with small molecule inhibitors called Histone deacetylase inhibitors (HDACi) have shown enhanced acetylation of the genome and are hence emerging as potential targets at the clinic. Type-specific inhibition of Class II HDACs has shown enhanced therapeutic benefits against developmental and neurodegenerative disorders. However, the structural identity of class-specific isoforms limits the potential of their inhibitors in precise targeting of their enzymes. Diverse strategies have been implemented to recognise the features in HDAC enzymes which may help in identifying isoform specificity factors. This work attempts a computational approach that combines in silico docking and energy-optimised pharmacophore (E-pharmacophore) mapping of 18 known HDAC inhibitors and has identified structural variations that regulate their interactions against the six Class II HDAC enzymes considered for the study. This combined approach establishes that inhibitors possessing higher number of aromatic rings in different structural regions might function as potent inhibitors, while inhibitors with scarce ring structures might point to compromised potency. This would aid the rationale for chemical optimisation and design of isoform selective HDAC inhibitors with enhanced affinity and therapeutic efficiency.

  4. Contribution of human hepatic cytochrome p450 isoforms to the metabolism of psychotropic drugs.

    Science.gov (United States)

    Niwa, Toshiro; Shiraga, Toshifumi; Ishii, Ikuko; Kagayama, Akira; Takagi, Akira

    2005-09-01

    The metabolic activities of six psychotropic drugs, diazepam, clotiazepam, tofisopam, etizolam, tandospirone, and imipramine, were determined for 14 isoforms of recombinant human hepatic cytochrome P450s (CYPs) and human liver microsomes by measuring the disappearance rate of parent compounds. In vitro kinetic studies revealed that Vmax/Km values in human liver microsomes were the highest for tofisopam, followed by tandospirone>clotiazepam>imipramine, diazepam, and etizolam. Among the recombinant CYPs, CYP3A4 exhibited the highest metabolic activities of all compounds except for clotiazepam and imipramine. The metabolism of clotiazepam was catalyzed by CYP2B6, CYP3A4, CYP2C18, and CYP2C19, and imipramine was metabolized by CYP2D6 most efficiently. In addition, the metabolic activities of diazepam, clotiazepam, and etizolam in human liver microsomes were inhibited by 2.5 microM ketoconazole, a CYP3A4 inhibitor, by 97.5%, 65.1%, and 83.5%, respectively, and the imipramine metabolism was not detected after the addition of 1 or 10 microM quinidine, a CYP2D6 inhibitor. These results suggest that the psychotropic drugs investigated are metabolized predominantly by CYP3A4, except that CYP2D6 catalyzes the metabolism of imipramine. In addition, this approach based on the disappearance rate appears to be useful for the identification of the responsible CYP isoform(s) of older drugs, for which metabolic profiles have not been reported. PMID:16141545

  5. Role of p73 Dinucleotide Polymorphism in Prostate Cancer and p73 Protein Isoform Balance

    Directory of Open Access Journals (Sweden)

    L. Michael Carastro

    2014-01-01

    Full Text Available Background. Molecular markers for prostate cancer (PCa risks are currently lacking. Here we address the potential association of a dinucleotide polymorphism (DNP in exon 2 of the p73 gene with PCa risk/progression and discern any disruption of p73 protein isoforms levels in cells harboring a p73 DNP allele. Methods. We investigated the association between p73 DNP genotype and PCa risk/aggressiveness and survival by fitting logistic regression models in 1,292 incident cases and 682 controls. Results. Although we detected no association between p73 DNP and PCa risk, a significant inverse relationship between p73 DNP and PCa aggressiveness (AT/AT + GC/AT versus GC/GC, OR = 0.55, 95%Cl = 0.31–0.99 was detected. Also, p73 DNP is marginally associated with overall death (dominant model, HR = 0.76, 95%Cl = 0.57–1.00, P=0.053 as well as PCa specific death (HR = 0.69, 95%Cl = 0.45–1.06, P=0.09. Western blot analyses for p73 protein isoforms indicate that cells heterozygous for the p73 DNP have lower levels of ∆Np73 relative to TAp73 (P<0.001. Conclusions. Our findings are consistent with an association between p73 DNP and low risk for PCa aggressiveness by increasing the expressed TAp73/∆Np73 protein isoform ratio.

  6. Mechanisms controlling Pax6 isoform expression in the retina have been conserved between teleosts and mammals.

    Science.gov (United States)

    Lakowski, Jörn; Majumder, Anirban; Lauderdale, James D

    2007-07-15

    The Pax6 gene plays several roles in retinal development, including control of cell proliferation, maintenance of the retinogenic potential of progenitor cells, and cell fate specification. Emerging evidence suggests that these different aspects of Pax6 gene function are mediated by different isoforms of the Pax6 protein; however, relatively little is known about the spatiotemporal expression of Pax6 isoforms in the vertebrate retina. Using bacterial artificial chromosome (BAC) technology, we modified a zebrafish Pax6a BAC such that we could distinguish paired-containing Pax6a transcripts from paired-less Pax6a transcripts. In the zebrafish, the spatial and temporal onset of expression of these transcripts suggests that the paired-less isoform is involved in the cell fate decision leading to the generation of amacrine cells; however, because of limitations associated with transient transgenic analysis, it was not feasible to establish whether this promoter was active in all amacrine cells or in a specific population of amacrine cells. By making mice transgenic for the zebrafish Pax6a BAC reporter transgene, we were able to show that paired-containing and paired-less Pax6a transcripts were differentially expressed in amacrine subpopulations. Our study also directly demonstrates the functional conservation of the regulatory mechanisms governing Pax6 transcription in teleosts and mammals.

  7. Novel isoform of adaptor protein ITSN1 forms homodimers via its C-terminus

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    Skrypkina I. Ya.

    2011-06-01

    Full Text Available Aim. Previously we have identified a novel isoform of endocytic adaptor protein ITSN1 designated as ITSN122a. Western blot revealed two immunoreactive bands of 120 and 250 kDa that corresponded to ITSN1-22a. The goal of this study was to investigate the possibility of dimer formation by the novel isoform. Methods. Dimerization ability of ITSN1-22a was tested by immunoprecipitation and subsequent Western blot analysis. To specify the region responsible for dimerization, site-directed mutagenesis and truncation analysis were carried out. Inhibition of endocytosis by potassium depletion and EGF stimulation of HEK293 were performed. Results. We have found that ITSN1-22a forms dimers in HEK293 cells. The dimerization of ITSN1-22a was mediated by C-terminal domain. We showed that cysteines C1016 and C1019 were involved in homodimerization. Inhibition of clathrin-mediated endocytosis and mitogen stimulation did not affect ITSN1-22a dimer formation. Conclusions. ITSN1-22a is the only one known ITSN1 isoform, which is capable to form homodimers via disulphide bonds. This could be important for the formation of protein complexes containing ITSN1 molecules.

  8. Differential expression of two activating transcription factor 5 isoforms in papillary thyroid carcinoma

    Science.gov (United States)

    Vicari, Luisa; La Rosa, Cristina; Forte, Stefano; Calabrese, Giovanna; Colarossi, Cristina; Aiello, Eleonora; Salluzzo, Salvatore; Memeo, Lorenzo

    2016-01-01

    Background Activating transcription factor 5 (ATF5) is a member of the activating transcription/cAMP response element-binding protein family of basic leucine zipper proteins that plays an important role in cell survival, differentiation, proliferation, and apoptosis. The ATF5 gene generates two transcripts: ATF5 isoform 1 and ATF5 isoform 2. A number of studies indicate that ATF5 could be an attractive target for therapeutic intervention in several tumor types; however, so far, the role of ATF5 has not been investigated in papillary thyroid carcinoma (PTC). Methods Quantitative real-time reverse transcription polymerase chain reaction and immuno-histochemical staining were used to study ATF5 mRNA and protein expression in PTC. Results We report here that ATF5 is expressed more in PTC tissue than in normal thyroid tissue. Furthermore, this is the first study that describes the presence of both ATF5 isoforms in PTC. Conclusion These findings could provide potential applications in PTC cancer treatment.

  9. Expression of Monocarboxylate Transporter Isoforms in Rat Skeletal Muscle Under Hypoxic Preconditioning and Endurance Training.

    Science.gov (United States)

    Saxena, Saurabh; Shukla, Dhananjay; Bansal, Anju

    2016-03-01

    Previously, we have reported the regulation of monocarboxylate transporters (MCT)1 and MCT4 by physiological stimuli such as hypoxia and exercise. In the present study, we have evaluated the effect of hypoxic preconditioning and training on expression of different MCT isoforms in muscles. We found the increased mRNA expression of MCT1, MCT11, and MCT12 after hypoxic preconditioning with cobalt chloride and training. However, the expression of other MCT isoforms increased marginally or even reduced after hypoxic preconditioning. Only the protein expression of MCT1 increased after hypoxia preconditioning. MCT2 protein expression increased after training only and MCT4 protein expression decreased both in preconditioning and hypoxic training. Furthermore, we found decreased plasma lactate level during hypoxia preconditioning (0.74-fold), exercise (0.78-fold), and hypoxia preconditioning along with exercise (0.67-fold), which indicates increased lactate uptake by skeletal muscle. The protein-protein interactions with hypoxia inducible factor-1 and MCT isoforms were also evaluated, but no interaction was found. In conclusion, we say that almost all MCTs are expressed in red gastrocnemius muscle at the mRNA level and their expression is regulated differently under hypoxia preconditioning and exercise condition. PMID:26716978

  10. Temperature-dependent developmental variation in lobster muscle myosin heavy chain isoforms.

    Science.gov (United States)

    Magnay, J L; Holmes, J M; Neil, D M; El Haj, A J

    2003-10-16

    The temperature- and developmental-regulation of myosin heavy chain (MyHC) expression and primary sequence was investigated in the abdominal musculature of developing Homarus gammarus larvae acclimated to 10, 14 and 19+/-1 degrees C. MyHC loop 1 (ATP binding) and loop 2 (actin binding) regions were sequenced and compared. The deduced amino acid sequence of MyHC loop 1 showed a development-related increase in net charge from +1 to +2 between larval stages 1 and 2, which was not temperature-dependent. In post-settled stage 9 larvae, minor shifts in amino acid sequence occurred at 19 degrees C, and corresponded to a significant up-regulation of fast myosin mRNA expression. However, no temperature-specific loop 1 isoforms were detected. The deduced amino acid sequence of MyHC loop 2 was not affected by temperature, and the net charge remained +4 throughout development. These findings contrast to previous studies using the common carp, in which temperature-specific MyHC isoform genes were expressed in response to disparate thermal regimes. This raises the question as to whether arthropods do not express specific temperature isoforms but instead rely on shifts in fibre type to accommodate alterations in thermal environment. PMID:14563558

  11. Differential expression of a new isoform of DLG2 in renal oncocytoma

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    Kovacs Gyula

    2006-04-01

    Full Text Available Abstract Background Renal oncocytoma, a benign tumour of the kidney, may pose a differential diagnostic problem due to overlapping phenotype with chromophobe renal cell carcinoma or other types of renal cell tumours. Therefore, identification of molecular markers would be of great value for molecular diagnostics of this tumour type. Methods In the current study we applied various techniques, including Affymetrix microarray hybridization and semiquantitative RT-PCR, to identify genes expressed differentially in renal oncocytomas. Subsequently, we used RACE and Northern blot hybridization to characterize the potential candidates for molecular diagnosis. Results We have identified new isoform of DLG2 gene, which contains 3'-end exons of the known DLG2 gene along with the hypothetical gene FLJ37266. The new isoform is specifically upregulated in renal oncocytoma, whereas the known DLG2 gene is downregulated in this type of kidney tumour. Conclusion The new isoform of DLG2 is the promising candidate gene for molecular differential diagnostics of renal oncocytoma.

  12. Developmentally regulated switch in alternatively spliced SNAP-25 isoforms alters facilitation of synaptic transmission.

    Science.gov (United States)

    Bark, Christina; Bellinger, Frederick P; Kaushal, Ashutosh; Mathews, James R; Partridge, L Donald; Wilson, Michael C

    2004-10-01

    Although the basic molecular components that promote regulated neurotransmitter release are well established, the contribution of these proteins as regulators of the plasticity of neurotransmission and refinement of synaptic connectivity during development is elaborated less fully. For example, during the period of synaptic growth and maturation in brain, the expression of synaptosomal protein 25 kDa (SNAP-25), a neuronal t-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) essential for action potential-dependent neuroexocytosis, is altered through alternative splicing of pre-mRNA transcripts. We addressed the role of the two splice-variant isoforms of SNAP-25 with a targeted mouse mutation that impairs the shift from SNAP-25a to SNAP-25b. Most of these mutant mice die between 3 and 5 weeks of age, which coincides with the time when SNAP-25b expression normally reaches mature levels in brain and synapse formation is essentially completed. The altered expression of these SNAP-25 isoforms influences short-term synaptic function by affecting facilitation but not the initial probability of release. This suggests that mechanisms controlling alternative splicing between SNAP-25 isoforms contribute to a molecular switch important for survival that helps to guide the transition from immature to mature synaptic connections, as well as synapse regrowth and remodeling after neural injury.

  13. Peroxiredoxin isoforms are associated with cardiovascular risk factors in type 2 diabetes mellitus

    International Nuclear Information System (INIS)

    The production of oxygen free radicals in type 2 diabetes mellitus contributes to the development of complications, especially the cardiovascular-related ones. Peroxiredoxins (PRDXs) are antioxidant enzymes that combat oxidative stress. The aim of this study was to investigate the associations between the levels of PRDX isoforms (1, 2, 4, and 6) and cardiovascular risk factors in type 2 diabetes mellitus. Fifty-three patients with type 2 diabetes mellitus (28F/25M) and 25 healthy control subjects (7F/18M) were enrolled. We measured the plasma levels of each PRDX isoform and analyzed their correlations with cardiovascular risk factors. The plasma PRDX1, -2, -4, and -6 levels were higher in the diabetic patients than in the healthy control subjects. PRDX2 and -6 levels were negatively correlated with diastolic blood pressure, fasting blood sugar, and hemoglobin A1c. In contrast, PRDX1 levels were positively correlated with low-density lipoprotein and C-reactive protein levels. PRDX4 levels were negatively correlated with triglycerides. In conclusion, PRDX1, -2, -4, and -6 showed differential correlations with a variety of traditional cardiovascular risk factors. These results should encourage further research into the crosstalk between PRDX isoforms and cardiovascular risk factors

  14. Human heterochromatin protein 1 isoforms regulate androgen receptor signaling in prostate cancer.

    Science.gov (United States)

    Itsumi, Momoe; Shiota, Masaki; Yokomizo, Akira; Kashiwagi, Eiji; Takeuchi, Ario; Tatsugami, Katsunori; Inokuchi, Junichi; Song, Yoohyun; Uchiumi, Takeshi; Naito, Seiji

    2013-06-01

    Androgen receptor (AR) signaling is critical for the tumorigenesis and development of prostate cancer, as well as the progression to castration-resistant prostate cancer. We previously showed that the heterochromatin protein 1 (HP1) β isoform plays a critical role in transactivation of AR signaling as an AR coactivator that promotes prostate cancer cell proliferation. However, the roles of other HP1 isoforms, HP1α and HP1γ, in AR expression and prostate cancer remain unclear. Here, we found that knockdown of HP1γ, but not HP1α, reduced AR expression and cell proliferation by inducing cell cycle arrest at G1 phase in LNCaP cells. Conversely, overexpression of full-length HP1α and its C-terminal deletion mutant increased AR expression and cell growth, whereas overexpression of HP1γ had no effect. Similarly, HP1α overexpression promoted 22Rv1 cell growth, whereas HP1γ knockdown reduced the proliferation of CxR cells, a castration-resistant LNCaP derivative. Taken together, HP1 isoforms distinctly augment AR signaling and cell growth in prostate cancer. Therefore, silencing of HP1β and HP1γ may be a promising therapeutic strategy for treatment of prostate cancer.

  15. Estrogen receptor isoforms and progestin hormone dependence in a mouse mammary tumor model.

    Science.gov (United States)

    Actis, A M; Caruso, S P; Levin, E

    1994-09-01

    The close interaction between receptors and other transcription factors suggests that their corresponding transducing signals can trigger functional and structural changes in other related molecules. The effect of a progestinic agent, medroxyprogesterone acetate (MPA), on some of the estrogen-receptor (ER) parameters was studied in 2 murine mammary tumor sublines with different progestin hormone dependence for their respective growth. The relative binding affinity of estradiol and tamoxifen for the ER, the receptor content and the ER isoforms studied by HPLC were determined in the hormone-autonomous (HA) and the hormone-dependent (HD) tumor sublines. In the HA subline administration of MPA did not modify the tumor growth rate, whereas this was accelerated in the HD subline. The ER content was clearly increased in the HD tumor subline, but not in the HA subline, compared with the untreated controls. In contrast, the E2 and tamoxifen relative binding affinity for the ER and the isoform profiles were affected by MPA treatment in the HA, but not in the HD tumor subline. The functional change (decrease in relative binding affinity) can be attributed to the appearance of a lower-molecular-size ER isoform under the progestinic treatment. Modifications in one receptor molecule by the action of ligands corresponding to another type of receptor show the interconection between transcription factors and the necessity of broadening conventional concepts regarding hormone dependence in mammary tumorigenesis. PMID:8077051

  16. Duplicated CFTR isoforms in eels diverged in regulatory structures and osmoregulatory functions.

    Science.gov (United States)

    Wong, Marty Kwok-Shing; Pipil, Supriya; Kato, Akira; Takei, Yoshio

    2016-09-01

    Two cystic fibrosis transmembrane conductance regulator (CFTR) isoforms, CFTRa and CFTRb, were cloned in Japanese eel and their structures and functions were studied in different osmoregulatory tissues in freshwater (FW) and seawater (SW) eels. Molecular phylogenetic results suggested that the CFTR duplication in eels occurred independently of the duplication event in salmonid. CFTRa was expressed in the intestine and kidney and downregulated in both tissues in SW eels, while CFTRb was specifically expressed in the gill and greatly upregulated in SW eels. Structurally, the CFTR isoforms are similar in most functional domains except the regulatory R domain, where the R domain of CFTRa is similar to that of human CFTR but the R domain of CFTRb is unique in having high intrinsic negative charges and fewer phosphorylation sites, suggesting divergence of isoforms in terms of gating properties and hormonal regulation. Immunohistochemical results showed that CFTR was localized on the apical regions of SW ionocytes, suggesting a Cl(-) secretory role as in other teleosts. In intestine and kidney, however, immunoreactive CFTR was mostly found in the cytosolic vesicles in FW eels, indicating that Cl(-) channel activity could be low at basal conditions, but could be rapidly increased by membrane insertion of the stored channels. Guanylin (GN), a known hormone that increases CFTR activity in mammalian intestine, failed to redistribute CFTR and to affect its expression in eel intestine. The results suggested that GN-independent CFTR regulation is present in eel intestine and kidney. PMID:27322796

  17. Semisynthetic and Natural Garcinoic Acid Isoforms as New mPGES-1 Inhibitors.

    Science.gov (United States)

    Alsabil, Khaled; Suor-Cherer, Sorphon; Koeberle, Andreas; Viault, Guillaume; Lavaud, Alexis; Temml, Veronika; Waltenberger, Birgit; Schuster, Daniela; Litaudon, Marc; Lorkowski, Stefan; de Vaumas, René; Helesbeux, Jean-Jacques; Guilet, David; Stuppner, Hermann; Werz, Oliver; Seraphin, Denis; Richomme, Pascal

    2016-07-01

    Over the last twenty years, tocotrienol analogues raised great interest because of their higher level and larger domain of biological activities when compared with tocopherols. Amongst the most promising therapeutic application, anti-inflammatory potency has been evaluated through the inhibition of various mediators of inflammation. Here, we worked on the isolation of two natural isoforms of garcinoic acid (i.e., δ and γ) from two different sources, respectively, Garcinia kola seeds and Garcinia amplexicaulis bark. We also developed semisynthetic strategies to access the other two non-natural α- and β-garcinoic acid isoforms. In the next stage of our work, microsomal prostaglandin E2 synthase was defined as a target to evaluate the anti-inflammatory potential of the four garcinoic acid isomers. Both dimethylated isoforms, β- and γ-garcinoic acid, exhibited the lowest IC50, 2.8 µM and 2.0 µM, respectively. These results showed that the affinity of tocotrienol analogues to microsomal prostaglandin E2 synthase-1 most probably contributes to the anti-inflammatory potential of this class of derivatives. PMID:27286327

  18. Circadian rhythmicity of active GSK3 isoforms modulates molecular clock gene rhythms in the suprachiasmatic nucleus.

    Science.gov (United States)

    Besing, Rachel C; Paul, Jodi R; Hablitz, Lauren M; Rogers, Courtney O; Johnson, Russell L; Young, Martin E; Gamble, Karen L

    2015-04-01

    The suprachiasmatic nucleus (SCN) drives and synchronizes daily rhythms at the cellular level via transcriptional-translational feedback loops comprising clock genes such as Bmal1 and Period (Per). Glycogen synthase kinase 3 (GSK3), a serine/threonine kinase, phosphorylates at least 5 core clock proteins and shows diurnal variation in phosphorylation state (inactivation) of the GSK3β isoform. Whether phosphorylation of the other primary isoform (GSK3α) varies across the subjective day-night cycle is unknown. The purpose of this study was to determine if the endogenous rhythm of GSK3 (α and β) phosphorylation is critical for rhythmic BMAL1 expression and normal amplitude and periodicity of the molecular clock in the SCN. Significant circadian rhythmicity of phosphorylated GSK3 (α and β) was observed in the SCN from wild-type mice housed in constant darkness for 2 weeks. Importantly, chronic activation of both GSK3 isoforms impaired rhythmicity of the GSK3 target BMAL1. Furthermore, chronic pharmacological inhibition of GSK3 with 20 µM CHIR-99021 enhanced the amplitude and shortened the period of PER2::luciferase rhythms in organotypic SCN slice cultures. These results support the model that GSK3 activity status is regulated by the circadian clock and that GSK3 feeds back to regulate the molecular clock amplitude in the SCN.

  19. Changes in the expression of NO synthase isoforms after ozone: the effects of allergen exposure

    Directory of Open Access Journals (Sweden)

    Lee June-Hyuk

    2004-06-01

    Full Text Available Abstract Background The functional role of nitric oxide (NO and various nitric oxide synthase (NOS isoforms in asthma remains unclear. Objective This study investigated the effects of ozone and ovalbumin (OVA exposure on NOS isoforms. Methods The expression of inducible NOS (iNOS, neuronal NOS (nNOS, and endothelial NOS (eNOS in lung tissue was measured. Enhanced pause (Penh was measured as a marker of airway obstruction. Nitrate and nitrite in bronchoalveolar lavage (BAL fluid were measured using a modified Griess reaction. Results The nitrate concentration in BAL fluid from the OVA-sensitized/ozone-exposed/OVA-challenged group was greater than that of the OVA-sensitized/saline-challenged group. Methacholine-induced Penh was increased in the OVA-sensitized/ozone-exposed/OVA-challenged group, with a shift in the dose-response curve to the left, compared with the OVA-sensitized/saline-challenged group. The levels of nNOS and eNOS were increased significantly in the OVA-sensitized/ozone-exposed/OVA-challenged group and the iNOS levels were reduced compared with the OVA-sensitized/saline-challenged group. Conclusion In mice, ozone is associated with increases in lung eNOS and nNOS, and decreases in iNOS. None of these enzymes are further affected by allergens, suggesting that the NOS isoforms play different roles in airway inflammation after ozone exposure.

  20. Glutamine synthetase isoforms in nitrogen-fixing soybean nodules: distinct oligomeric structures and thiol-based regulation.

    Science.gov (United States)

    Masalkar, Pintu D; Roberts, Daniel M

    2015-01-16

    Legume root nodule glutamine synthetase (GS) catalyzes the assimilation of ammonia produced by nitrogen fixation. Two GS isoform subtypes (GS1β and GS1γ) are present in soybean nodules. GS1γ isoforms differ from GS1β isoforms in terms of their susceptibility to reversible inhibition by intersubunit disulfide bond formation between C159 and C92 at the shared active site at subunit interfaces. Although nodule GS enzymes share 86% amino acid sequence identity, analytical ultracentrifugation experiments showed that GS1γ is a dodecamer, whereas the GS1β is a decamer. It is proposed that this difference contributes to the differential thiol sensitivity of each isoform, and that GS1γ1 may be a target of thiol-based regulation.

  1. EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Chevreux, Sylviane; Roudeau, Stephane; Deves, Guillaume; Ortega, Richard [Laboratoire de Chimie Nucleaire Analytique et Bioenvironnementale, CNRS UMR5084, Universite Bordeaux 1, Chemin du Solarium, F-33175 Gradignan cedex (France); Solari, Pier Lorenzo [Synchrotron SOLEIL, L' Orme des Merisiers, BP 48, F-91192 Gif-sur-Yvette cedex, Saint-Aubin (France); Alliot, Isabelle; Testemale, Denis; Hazemann, Jean Louis, E-mail: ortega@cenbg.in2p3.f [FAME, ESRF, 6 rue Jules Horowitz, BP220, F-38043 Grenoble cedex (France)

    2009-11-15

    Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

  2. EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

    Science.gov (United States)

    Chevreux, Sylviane; Solari, Pier Lorenzo; Roudeau, Stéphane; Deves, Guillaume; Alliot, Isabelle; Testemale, Denis; Hazemann, Jean Louis; Ortega, Richard

    2009-11-01

    Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

  3. Cloning and characterisation of a maize carotenoid cleavage dioxygenase (ZmCCD1) and its involvement in the biosynthesis of apocarotenoids with various roles in mutualistic and parasitic interactions

    OpenAIRE

    Sun, Z.; Hans, J.; Walter, M H; Matusova, R.; Beekwilder, M.J.; Verstappen, F.W.A.; Ming, Z.; Echteld, van, C.J.A.; Strack, D; Bisseling, T.; Bouwmeester, H.J.

    2008-01-01

    Colonisation of maize roots by arbuscular mycorrhizal (AM) fungi leads to the accumulation of apocarotenoids (cyclohexenone and mycorradicin derivatives). Other root apocarotenoids (strigolactones) are involved in signalling during early steps of the AM symbiosis but also in stimulation of germination of parasitic plant seeds. Both apocarotenoid classes are predicted to originate from cleavage of a carotenoid substrate by a carotenoid cleavage dioxygenase (CCD), but the precursors and cleavag...

  4. Activity of the acyl-CoA synthetase ACSL6 isoforms: role of the fatty acid Gate-domains

    Directory of Open Access Journals (Sweden)

    Siliakus Melvin

    2010-04-01

    Full Text Available Abstract Background Activation of fatty acids by acyl-CoA synthetase enzymes is required for de novo lipid synthesis, fatty acid catabolism, and remodeling of biological membranes. Human long-chain acyl-CoA synthetase member 6, ASCL6, is a form present in the plasma membrane of cells. Splicing events affecting the amino-terminus and alternative motifs near the ATP-binding site generate different isoforms of ACSL6. Results Isoforms with different fatty acid Gate-domain motifs have different activity and the form lacking this domain, isoform 3, showed no detectable activity. Enzymes truncated of the first 40 residues generate acyl-CoAs at a faster rate than the full-length protein. The gating residue, which prevents entry of the fatty acid substrate unless one molecule of ATP has already accessed the catalytic site, was identified as a tyrosine for isoform 1 and a phenylalanine for isoform 2 at position 319. All isoforms, with or without a fatty acid Gate-domain, as well as recombinant protein truncated of the N-terminus, can interact to form enzymatic complexes with identical or different isoforms. Conclusion The alternative fatty acid Gate-domain motifs are essential determinants for the activity of the human ACSL6 isoforms, which appear to act as homodimeric enzyme as well as in complex with other spliced forms. These findings provide evidence that the diversity of these enzyme species could produce the variety of acyl-CoA synthetase activities that are necessary to generate and repair the hundreds of lipid species present in membranes.

  5. Oligomeric properties and DNA binding specificities of repressor isoforms from the Streptomyces bacteriophage phiC31.

    Science.gov (United States)

    Wilson, S E; Smith, M C

    1998-05-15

    Three protein isoforms (74, 54 and 42 kDa) are expressed from repressor gene c in the Streptomyces temperate bacteriophage phiC31. Because expression of the two smaller isoforms, 54 and 42 kDa, is sufficient for superinfection immunity, the interaction between these isoforms was studied. The native 42 kDa repressor (Nat42) and an N-terminally 6x histidine-tagged 54 kDa isoform (His54) were shown by co-purification on a Ni-NTA column to interact in Streptomyces lividans . In vitro three repressor preparations, containing Nat42, His54 and the native 54 and 42 kDa isoforms expressed together (Nat54&42), were subjected to chemical crosslinking and gel filtration analysis. Homo- and hetero-tetramers were observed. Previous work showed that the smallest isoform bound to 17 bp operators containing aconservedinvertedrepeat (CIR) and that the CIRs were located at 16 loci throughout the phiC31 genome. One of the CIRs (CIR6) is believed to be critical for regulating the lytic pathway. The DNA binding activities of the three repressor preparations were studied using fragments containing CIRs (CIR3-CIR6) from the essential early region as templates for DNase I footprinting. Whereas Nat42 bound to CIR6, poorly to CIR5 but undetectably to CIR3 or CIR4, the Nat54&42 preparation could bind to all CIRs tested, albeit poorly to CIR3 and CIR4. The His54 isoform bound all CIRs tested. Isoforms expressed from the phiC31 repressor gene, like those which are expressed from many eukaryotic transcription factor genes, apparently have different binding specificities.

  6. Two Regions of the Tail Are Necessary for the Isoform-specific Functions of Nonmuscle Myosin IIB

    OpenAIRE

    Sato, Masaaki K.; Takahashi, Masayuki; Yazawa, Michio

    2007-01-01

    To function in the cell, nonmuscle myosin II molecules assemble into filaments through their C-terminal tails. Because myosin II isoforms most likely assemble into homo-filaments in vivo, it seems that some self-recognition mechanisms of individual myosin II isoforms should exist. Exogenous expression of myosin IIB rod fragment is thus expected to prevent the function of myosin IIB specifically. We expected to reveal some self-recognition sites of myosin IIB from the phenotype by expressing a...

  7. Evaluation of Hepcidin Isoforms in Hemodialysis Patients by a Proteomic Approach Based on SELDI-TOF MS

    OpenAIRE

    Oliviero Olivieri; Antonio Lupo; Nicola Martinelli; Albino Poli; Nicola Tessitore; Valeria Bedogna; Annalisa Castagna; Federica Zaninotto; Domenico Girelli; Natascia Campostrini

    2010-01-01

    The hepatic iron regulator hormone hepcidin consists, in its mature form, of 25 amino acids, but two other isoforms, hepcidin-20 and hepcidin-22, have been reported, whose biological meaning remains poorly understood. We evaluated hepcidin isoforms in sera from 57 control and 54 chronic haemodialysis patients using a quantitative proteomic approach based on SELDI-TOF-MS. Patients had elevated serum levels of both hepcidin-25 and hepcidin-20 as compared to controls (geometric means: 7.52 versu...

  8. Differential expression of intracellular and secreted osteopontin isoforms by murine macrophages in response to Toll-like receptor agonists.

    OpenAIRE

    Zhao, Wei; Wang, Lijuan; Zhang, Lei; Yuan, Chao; Kuo, Paul C.; Gao, Chengjiang

    2015-01-01

    Osteopontin (OPN), expressed by various immune cells, modulates both innate and adaptive immune responses. Different immune cells have shown differential expression of the two isoforms of OPN: secreted form of OPN (sOPN) and intracellular form of OPN (iOPN). However, the molecular mechanisms that control opn gene expression and the OPN isoforms produced by immune cells remain largely unknown. In this study, we demonstrate that OPN mRNA and protein expression are significantly up-regulated upo...

  9. In Vitro Inhibitory Activities of the Extract of Hibiscus Sabdariffa L. (Family Malvaceae) on Selected Cytochrome P450 Isoforms

    OpenAIRE

    Johnson, Showande Segun; Oyelola, Fakeye Titilayo; Ari, Tolonen; Juho, Hokkanen

    2013-01-01

    Literature is scanty on the interaction potential of Hibiscus sabdariffa L., plant extract with other drugs and the affected targets. This study was conducted to investigate the cytochrome P450 (CYP) isoforms that are inhibited by the extract of Hibiscus sabdariffa L. in vitro. The inhibition towards the major drug metabolizing CYP isoforms by the plant extract were estimated in human liver microsomal incubations, by monitoring the CYP-specific model reactions through previously validated N-i...

  10. Differential expression of Na+, K(+)-ATPase α-1 isoforms during seawater acclimation in the amphidromous galaxiid fish Galaxias maculatus.

    Science.gov (United States)

    Urbina, Mauricio A; Schulte, Patricia M; Bystriansky, Jason S; Glover, Chris N

    2013-04-01

    Inanga (Galaxias maculatus) is an amphidromous fish with a well-known capacity to withstand a wide range of environmental salinities. To investigate the molecular mechanisms facilitating acclimation of inanga to seawater, several isoforms of the Na(+), K(+)-ATPase ion transporter were identified. This included three α-1 (a, b and c), an α-2 and two α-3 (a and b) isoforms. Phylogenetic analysis showed that the inanga α-1a and α-1b formed a clade with the α-1a and α-1b isoforms of rainbow trout, while another clade contained the α-1c isoforms of these species. The expression of all the α-1 isoforms was modulated after seawater exposure (28‰). In gills, the expression of the α-1a isoform was progressively down-regulated after seawater exposure, while the expression of the α-1b isoform was up-regulated. The α-1c isoform behaved similarly to the α-1a, although changes were less dramatic. Physiological indicators of salinity acclimation matched the time frame of the changes observed at the molecular level. A 24-h osmotic shock period was highlighted by small increases in plasma osmolality, plasma Na(+) and a decrease in muscle tissue water content. Thereafter, these values returned close to their pre-exposure (freshwater) values. Na(+), K(+)-ATPase activity showed a decreasing trend over the first 72 h following seawater exposure, but activity increased after 240 h. Our results indicate that inanga is an excellent osmoregulator, an ability that is conferred by the rapid activation of physiological and molecular responses to salinity change. PMID:23142926

  11. Loss of desmoplakin isoform I causes early onset cardiomyopathy and heart failure in a Naxos‐like syndrome

    Science.gov (United States)

    Uzumcu, A; Norgett, E E; Dindar, A; Uyguner, O; Nisli, K; Kayserili, H; Sahin, S E; Dupont, E; Severs, N J; Leigh, I M; Yuksel‐Apak, M; Kelsell, D P; Wollnik, B

    2006-01-01

    Background Desmosomes are cellular junctions important for intercellular adhesion and anchoring the intermediate filament (IF) cytoskeleton to the cell membrane. Desmoplakin (DSP) is the most abundant desmosomal protein with 2 isoforms produced by alternative splicing. Methods We describe a patient with a recessively inherited arrhythmogenic dilated cardiomyopathy with left and right ventricular involvement, epidermolytic palmoplantar keratoderma, and woolly hair. The patient showed a severe heart phenotype with an early onset and rapid progression to heart failure at 4 years of age. Results A homozygous nonsense mutation, R1267X, was found in exon 23 of the desmoplakin gene, which results in an isoform specific truncation of the larger DSPI isoform. The loss of most of the DSPI specific rod domain and C‐terminal area was confirmed by Western blotting and immunofluorescence. We further showed that the truncated DSPI transcript is unstable, leading to a loss of DSPI. DSPI is reported to be an obligate constituent of desmosomes and the only isoform present in cardiac tissue. To address this, we reviewed the expression of DSP isoforms in the heart. Our data suggest that DSPI is the major cardiac isoform but we also show that specific compartments of the heart have detectable DSPII expression. Conclusions This is the first description of a phenotype caused by a mutation affecting only one DSP isoform. Our findings emphasise the importance of desmoplakin and desmosomes in epidermal and cardiac function and additionally highlight the possibility that the different isoforms of desmoplakin may have distinct functional properties within the desmosome. PMID:16467215

  12. Influence of Temperature, Hypercapnia, and Development on the Relative Expression of Different Hemocyanin Isoforms in the Common Cuttlefish Sepia officinalis

    OpenAIRE

    Strobel, Anneli; Hu, Marian Y.A.; Gutowska, Magdalena A.; Lieb, Bernhard; Lucassen, Magnus; Melzner, Frank; Pörtner, Hans-Otto; Mark, Felix Christopher

    2012-01-01

    The cuttlefish Sepia officinalis expresses several hemocyanin isoforms with potentially different pH optima, indicating their reliance on efficient pH regulation in the blood. Ongoing ocean warming and acidification could influence the oxygen-binding properties of respiratory pigments in ectothermic marine invertebrates. This study examined whether S. officinalis differentially expresses individual hemocyanin isoforms to maintain optimal oxygen transport during development and ...

  13. Anaerobic crystallization and initial X-ray diffraction data of biphenyl 2,3-dioxygenase from Burkholderia xenovorans LB400: addition of agarose improved the quality of the crystals

    International Nuclear Information System (INIS)

    Biphenyl 2,3-dioxygenase from B. xenovorans LB400 and its variants BPDOP4 and BPDORR41 were crystallized using agarose gel and the crystals were characterized using X-ray diffraction. Biphenyl 2,3-dioxygenase (BPDO; EC 1.14.12.18) catalyzes the initial step in the degradation of biphenyl and some polychlorinated biphenyls (PCBs). BPDOLB400, the terminal dioxygenase component from Burkholderia xenovorans LB400, a proteobacterial species that degrades a broad range of PCBs, has been crystallized under anaerobic conditions by sitting-drop vapour diffusion. Initial crystals obtained using various polyethylene glycols as precipitating agents diffracted to very low resolution (∼8 Å) and the recorded reflections were diffuse and poorly shaped. The quality of the crystals was significantly improved by the addition of 0.2% agarose to the crystallization cocktail. In the presence of agarose, wild-type BPDOLB400 crystals that diffracted to 2.4 Å resolution grew in space group P1. Crystals of the BPDOP4 and BPDORR41 variants of BPDOLB400 grew in space group P21

  14. Immunopositivity for histone macroH2A1 isoforms marks steatosis-associated hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Francesca Rappa

    Full Text Available BACKGROUND: Hepatocellular carcinoma (HCC is one of the most common cancers worldwide. Prevention and risk reduction are important and the identification of specific biomarkers for early diagnosis of HCC represents an active field of research. Increasing evidence indicates that fat accumulation in the liver, defined as hepatosteatosis, is an independent and strong risk factor for developing an HCC. MacroH2A1, a histone protein generally associated with the repressed regions of chromosomes, is involved in hepatic lipid metabolism and is present in two alternative spliced isoforms, macroH2A1.1 and macroH2A1.2. These isoforms have been shown to predict lung and colon cancer recurrence but to our knowledge, their role in fatty-liver associated HCC has not been investigated previously. METHODS: We examined macroH2A1.1 and macroH2A1.2 protein expression levels in the liver of two murine models of fat-associated HCC, the high fat diet/diethylnistrosamine (DEN and the phosphatase and tensin homolog (PTEN liver specific knock-out (KO mouse, and in human liver samples of subjects with steatosis or HCC, using immunoblotting and immunohistochemistry. RESULTS: Protein levels for both macroH2A1 isoforms were massively upregulated in HCC, whereas macroH2A1.2 was specifically upregulated in steatosis. In addition, examination of human liver samples showed a significant difference (p<0.01 in number of positive nuclei in HCC (100% of tumor cells positive for either macroH2A1.1 or macroH2A1.2, when compared to steatosis (<2% of hepatocytes positive for either isoform. The steatotic areas flanking the tumors were highly immunopositive for macroH2A1.1 and macroH2A1.2. CONCLUSIONS: These data obtained in mice and humans suggest that both macroH2A1 isoforms may play a role in HCC pathogenesis and moreover may be considered as novel diagnostic markers for human HCC.

  15. Isoform-specific monobody inhibitors of small ubiquitin-related modifiers engineered using structure-guided library design.

    Science.gov (United States)

    Gilbreth, Ryan N; Truong, Khue; Madu, Ikenna; Koide, Akiko; Wojcik, John B; Li, Nan-Sheng; Piccirilli, Joseph A; Chen, Yuan; Koide, Shohei

    2011-05-10

    Discriminating closely related molecules remains a major challenge in the engineering of binding proteins and inhibitors. Here we report the development of highly selective inhibitors of small ubiquitin-related modifier (SUMO) family proteins. SUMOylation is involved in the regulation of diverse cellular processes. Functional differences between two major SUMO isoforms in humans, SUMO1 and SUMO2/3, are thought to arise from distinct interactions mediated by each isoform with other proteins containing SUMO-interacting motifs (SIMs). However, the roles of such isoform-specific interactions are largely uncharacterized due in part to the difficulty in generating high-affinity, isoform-specific inhibitors of SUMO/SIM interactions. We first determined the crystal structure of a "monobody," a designed binding protein based on the fibronectin type III scaffold, bound to the yeast homolog of SUMO. This structure illustrated a mechanism by which monobodies bind to the highly conserved SIM-binding site while discriminating individual SUMO isoforms. Based on this structure, we designed a SUMO-targeted library from which we obtained monobodies that bound to the SIM-binding site of human SUMO1 with K(d) values of approximately 100 nM but bound to SUMO2 400 times more weakly. The monobodies inhibited SUMO1/SIM interactions and, unexpectedly, also inhibited SUMO1 conjugation. These high-affinity and isoform-specific inhibitors will enhance mechanistic and cellular investigations of SUMO biology.

  16. Isoform-specific monobody inhibitors of small ubiquitin-related modifiers engineered using structure-guided library design

    Energy Technology Data Exchange (ETDEWEB)

    Gilbreth, Ryan N.; Truong, Khue; Madu, Ikenna; Koide, Akiko; Wojcik, John B.; Li, Nan-Sheng; Piccirilli, Joseph A.; Chen, Yuan; Koide, Shohei (UC); (CHNMC)

    2011-07-25

    Discriminating closely related molecules remains a major challenge in the engineering of binding proteins and inhibitors. Here we report the development of highly selective inhibitors of small ubiquitin-related modifier (SUMO) family proteins. SUMOylation is involved in the regulation of diverse cellular processes. Functional differences between two major SUMO isoforms in humans, SUMO1 and SUMO2/3, are thought to arise from distinct interactions mediated by each isoform with other proteins containing SUMO-interacting motifs (SIMs). However, the roles of such isoform-specific interactions are largely uncharacterized due in part to the difficulty in generating high-affinity, isoform-specific inhibitors of SUMO/SIM interactions. We first determined the crystal structure of a 'monobody,' a designed binding protein based on the fibronectin type III scaffold, bound to the yeast homolog of SUMO. This structure illustrated a mechanism by which monobodies bind to the highly conserved SIM-binding site while discriminating individual SUMO isoforms. Based on this structure, we designed a SUMO-targeted library from which we obtained monobodies that bound to the SIM-binding site of human SUMO1 with K{sub d} values of approximately 100 nM but bound to SUMO2 400 times more weakly. The monobodies inhibited SUMO1/SIM interactions and, unexpectedly, also inhibited SUMO1 conjugation. These high-affinity and isoform-specific inhibitors will enhance mechanistic and cellular investigations of SUMO biology.

  17. Interaction of meropenem with 'N' and 'B' isoforms of human serum albumin: a spectroscopic and molecular docking study.

    Science.gov (United States)

    Rehman, Md Tabish; Ahmed, Sarfraz; Khan, Asad U

    2016-09-01

    Carbapenems are used to control the outbreak of β-lactamases expressing bacteria. The effectiveness of drugs is influenced by its interaction with human serum albumin (HSA). Strong binding of carbapenems to HSA may lead to decreased bioavailability of the drug. The non-optimal drug dosage will provide a positive selection pressure on bacteria to develop resistance. Here, we investigated the interaction between meropenem and HSA at physiological pH 7.5 (N-isoform HSA) and non-physiological pH 9.2 (B-isoform HSA). Results showed that meropenem quenches the fluorescence of both 'N' and 'B' isoforms of HSA (ΔG < 0 and binding constant ~10(4) M(-1)). Electrostatic interactions and van der Waal interactions along with H-bonds stabilized the complex of meropenem with 'N' and 'B' isoforms of HSA, respectively. Molecular docking results revealed that meropenem binds to HSA near Sudlow's site II (subdomain IIIA) close to Trp-214 with a contribution of a few residues of subdomain IIA. CD spectroscopy showed a change in the conformation of both the isoforms of HSA upon meropenem binding. The catalytic efficiency of HSA (only N-isoform) on p-nitrophenyl acetate was increased primarily due to a decrease in Km and an increase in kcat values. This study provides an insight into the molecular basis of interaction between meropenem and HSA.

  18. The Regulation of Nitric Oxide Synthase Isoform Expression in Mouse and Human Fallopian Tubes: Potential Insights for Ectopic Pregnancy

    Directory of Open Access Journals (Sweden)

    Junting Hu

    2014-12-01

    Full Text Available Nitric oxide (NO is highly unstable and has a half-life of seconds in buffer solutions. It is synthesized by NO-synthase (NOS, which has been found to exist in the following three isoforms: neuro nitric oxide synthase (nNOS, inducible nitric oxide synthase (iNOS, and endothelial nitric oxide synthase (eNOS. NOS activity is localized in the reproductive tracts of many species, although direct evidence for NOS isoforms in the Fallopian tubes of mice is still lacking. In the present study, we investigated the expression and regulation of NOS isoforms in the mouse and human Fallopian tubes during the estrous and menstrual cycles, respectively. We also measured isoform expression in humans with ectopic pregnancy and in mice treated with lipopolysaccharide (LPS. Our results confirmed the presence of different NOS isoforms in the mouse and human Fallopian tubes during different stages of the estrous and menstrual cycles and showed that iNOS expression increased in the Fallopian tubes of women with ectopic pregnancy and in LPS-treated mice. Elevated iNOS activity might influence ovulation, cilia beats, contractility, and embryo transportation in such a manner as to increase the risk of ectopic pregnancy. This study has provided morphological and molecular evidence that NOS isoforms are present and active in the human and mouse Fallopian tubes and suggests that iNOS might play an important role in both the reproductive cycle and infection-induced ectopic pregnancies.

  19. Two-dimensional zymography differentiates gelatinase isoforms in stimulated microglial cells and in brain tissues of acute brain injuries.

    Science.gov (United States)

    Chen, Shanyan; Meng, Fanjun; Chen, Zhenzhou; Tomlinson, Brittany N; Wesley, Jennifer M; Sun, Grace Y; Whaley-Connell, Adam T; Sowers, James R; Cui, Jiankun; Gu, Zezong

    2015-01-01

    Excessive activation of gelatinases (MMP-2/-9) is a key cause of detrimental outcomes in neurodegenerative diseases. A single-dimension zymography has been widely used to determine gelatinase expression and activity, but this method is inadequate in resolving complex enzyme isoforms, because gelatinase expression and activity could be modified at transcriptional and posttranslational levels. In this study, we investigated gelatinase isoforms under in vitro and in vivo conditions using two-dimensional (2D) gelatin zymography electrophoresis, a protocol allowing separation of proteins based on isoelectric points (pI) and molecular weights. We observed organomercuric chemical 4-aminophenylmercuric acetate-induced activation of MMP-2 isoforms with variant pI values in the conditioned medium of human fibrosarcoma HT1080 cells. Studies with murine BV-2 microglial cells indicated a series of proform MMP-9 spots separated by variant pI values due to stimulation with lipopolysaccharide (LPS). The MMP-9 pI values were shifted after treatment with alkaline phosphatase, suggesting presence of phosphorylated isoforms due to the proinflammatory stimulation. Similar MMP-9 isoforms with variant pI values in the same molecular weight were also found in mouse brains after ischemic and traumatic brain injuries. In contrast, there was no detectable pI differentiation of MMP-9 in the brains of chronic Zucker obese rats. These results demonstrated effective use of 2D zymography to separate modified MMP isoforms with variant pI values and to detect posttranslational modifications under different pathological conditions.

  20. Purification and characterization of soluble (cytosolic) and bound (cell wall) isoforms of invertases in barley (Hordeum vulgare) elongating stem tissue

    Science.gov (United States)

    Karuppiah, N.; Vadlamudi, B.; Kaufman, P. B.

    1989-01-01

    Three different isoforms of invertases have been detected in the developing internodes of barley (Hordeum vulgare). Based on substrate specificities, the isoforms have been identified to be invertases (beta-fructosidases EC 3.2.1.26). The soluble (cytosolic) invertase isoform can be purified to apparent homogeneity by diethylaminoethyl cellulose, Concanavalin-A Sepharose, organo-mercurial Sepharose, and Sephacryl S-300 chromatography. A bound (cell wall) invertase isoform can be released by 1 molar salt and purified further by the same procedures as above except omitting the organo-mercurial Sepharose affinity chromatography step. A third isoform of invertase, which is apparently tightly associated with the cell wall, cannot be isolated yet. The soluble and bound invertase isoforms were purified by factors of 60- and 7-fold, respectively. The native enzymes have an apparent molecular weight of 120 kilodaltons as estimated by gel filtration. They have been identified to be dimers under denaturing and nondenaturing conditions. The soluble enzyme has a pH optimum of 5.5, Km of 12 millimolar, and a Vmax of 80 micromole per minute per milligram of protein compared with cell wall isozyme which has a pH optimum of 4.5, Km of millimolar, and a Vmax of 9 micromole per minute per milligram of protein.