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Sample records for mutant alleles reveal

  1. Characterization of a null allelic mutant of the rice NAL1 gene reveals its role in regulating cell division.

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    Dan Jiang

    Full Text Available Leaf morphology is closely associated with cell division. In rice, mutations in Narrow leaf 1 (NAL1 show narrow leaf phenotypes. Previous studies have shown that NAL1 plays a role in regulating vein patterning and increasing grain yield in indica cultivars, but its role in leaf growth and development remains unknown. In this report, we characterized two allelic mutants of NARROW LEAF1 (NAL1, nal1-2 and nal1-3, both of which showed a 50% reduction in leaf width and length, as well as a dwarf culm. Longitudinal and transverse histological analyses of leaves and internodes revealed that cell division was suppressed in the anticlinal orientation but enhanced in the periclinal orientation in the mutants, while cell size remained unaltered. In addition to defects in cell proliferation, the mutants showed abnormal midrib in leaves. Map-based cloning revealed that nal1-2 is a null allelic mutant of NAL1 since both the whole promoter and a 404-bp fragment in the first exon of NAL1 were deleted, and that a 6-bp fragment was deleted in the mutant nal1-3. We demonstrated that NAL1 functions in the regulation of cell division as early as during leaf primordia initiation. The altered transcript level of G1- and S-phase-specific genes suggested that NAL1 affects cell cycle regulation. Heterogeneous expression of NAL1 in fission yeast (Schizosaccharomyces pombe further supported that NAL1 affects cell division. These results suggest that NAL1 controls leaf width and plant height through its effects on cell division.

  2. Mutant power: using mutant allele collections for yeast functional genomics.

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    Norman, Kaitlyn L; Kumar, Anuj

    2016-03-01

    The budding yeast has long served as a model eukaryote for the functional genomic analysis of highly conserved signaling pathways, cellular processes and mechanisms underlying human disease. The collection of reagents available for genomics in yeast is extensive, encompassing a growing diversity of mutant collections beyond gene deletion sets in the standard wild-type S288C genetic background. We review here three main types of mutant allele collections: transposon mutagen collections, essential gene collections and overexpression libraries. Each collection provides unique and identifiable alleles that can be utilized in genome-wide, high-throughput studies. These genomic reagents are particularly informative in identifying synthetic phenotypes and functions associated with essential genes, including those modeled most effectively in complex genetic backgrounds. Several examples of genomic studies in filamentous/pseudohyphal backgrounds are provided here to illustrate this point. Additionally, the limitations of each approach are examined. Collectively, these mutant allele collections in Saccharomyces cerevisiae and the related pathogenic yeast Candida albicans promise insights toward an advanced understanding of eukaryotic molecular and cellular biology. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. An extensive allelic series of Drosophila kae1 mutants reveals diverse and tissue-specific requirements for t6A biogenesis

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    Lin, Ching-Jung; Smibert, Peter; Zhao, Xiaoyu; Hu, Jennifer F.; Ramroop, Johnny; Kellner, Stefanie M.; Benton, Matthew A.; Govind, Shubha; Dedon, Peter C.; Sternglanz, Rolf; Lai, Eric C.

    2015-01-01

    N6-threonylcarbamoyl-adenosine (t6A) is one of the few RNA modifications that is universally present in life. This modification occurs at high frequency at position 37 of most tRNAs that decode ANN codons, and stabilizes cognate anticodon–codon interactions. Nearly all genetic studies of the t6A pathway have focused on single-celled organisms. In this study, we report the isolation of an extensive allelic series in the Drosophila ortholog of the core t6A biosynthesis factor Kae1. kae1 hemizygous larvae exhibit decreases in t6A that correlate with allele strength; however, we still detect substantial t6A-modified tRNAs even during the extended larval phase of null alleles. Nevertheless, complementation of Drosophila Kae1 and other t6A factors in corresponding yeast null mutants demonstrates that these metazoan genes execute t6A synthesis. Turning to the biological consequences of t6A loss, we characterize prominent kae1 melanotic masses and show that they are associated with lymph gland overgrowth and ectopic generation of lamellocytes. On the other hand, kae1 mutants exhibit other phenotypes that reflect insufficient tissue growth. Interestingly, whole-tissue and clonal analyses show that strongly mitotic tissues such as imaginal discs are exquisitely sensitive to loss of kae1, whereas nonproliferating tissues are less affected. Indeed, despite overt requirements of t6A for growth of many tissues, certain strong kae1 alleles achieve and sustain enlarged body size during their extended larval phase. Our studies highlight tissue-specific requirements of the t6A pathway in a metazoan context and provide insights into the diverse biological roles of this fundamental RNA modification during animal development and disease. PMID:26516084

  4. Characterization of a Weak Allele of Zebrafish cloche Mutant

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    Ma, Ning; Huang, Zhibin; Chen, Xiaohui; He, Fei; Wang, Kun; Liu, Wei; Zhao, Linfeng; Xu, Xiangmin; Liao, Wangjun; Ruan, Hua; Luo, Shenqiu; Zhang, Wenqing

    2011-01-01

    Hematopoiesis is a complicated and dynamic process about which the molecular mechanisms remain poorly understood. Danio rerio (zebrafish) is an excellent vertebrate system for studying hematopoiesis and developmental mechanisms. In the previous study, we isolated and identified a cloche 172 (clo 172) mutant, a novel allele compared to the original cloche (clo) mutant, through using complementation test and initial mapping. Here, according to whole mount in-situ hybridization, we report that the endothelial cells in clo 172 mutant embryos, although initially developed, failed to form the functional vascular system eventually. In addition, further characterization indicates that the clo 172 mutant exhibited weaker defects instead of completely lost in primitive erythroid cells and definitive hematopoietic cells compared with the clo s5 mutant. In contrast, primitive myeloid cells were totally lost in clo 172 mutant. Furthermore, these reappeared definitive myeloid cells were demonstrated to initiate from the remaining hematopoietic stem cells (HSCs) in clo 172 mutant, confirmed by the dramatic decrease of lyc in clo 172 runx1w84x double mutant. Collectively, the clo 172 mutant is a weak allele compared to the clo s5 mutant, therefore providing a model for studying the early development of hematopoietic and vascular system, as well as an opportunity to further understand the function of the cloche gene. PMID:22132109

  5. Mutant Allele-Specific Uncoupling of PENETRATION3 Functions Reveals Engagement of the ATP-Binding Cassette Transporter in Distinct Tryptophan Metabolic Pathways1[OPEN

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    Lu, Xunli; Dittgen, Jan; Piślewska-Bednarek, Mariola; Molina, Antonio; Schneider, Bernd; Doubský, Jan; Schneeberger, Korbinian; Schulze-Lefert, Paul

    2015-01-01

    Arabidopsis (Arabidopsis thaliana) PENETRATION (PEN) genes quantitatively contribute to the execution of different forms of plant immunity upon challenge with diverse leaf pathogens. PEN3 encodes a plasma membrane-resident pleiotropic drug resistance-type ATP-binding cassette transporter and is thought to act in a pathogen-inducible and PEN2 myrosinase-dependent metabolic pathway in extracellular defense. This metabolic pathway directs the intracellular biosynthesis and activation of tryptophan-derived indole glucosinolates for subsequent PEN3-mediated efflux across the plasma membrane at pathogen contact sites. However, PEN3 also functions in abiotic stress responses to cadmium and indole-3-butyric acid (IBA)-mediated auxin homeostasis in roots, raising the possibility that PEN3 exports multiple functionally unrelated substrates. Here, we describe the isolation of a pen3 allele, designated pen3-5, that encodes a dysfunctional protein that accumulates in planta like wild-type PEN3. The specific mutation in pen3-5 uncouples PEN3 functions in IBA-stimulated root growth modulation, callose deposition induced with a conserved peptide epitope of bacterial flagellin (flg22), and pathogen-inducible salicylic acid accumulation from PEN3 activity in extracellular defense, indicating the engagement of multiple PEN3 substrates in different PEN3-dependent biological processes. We identified 4-O-β-d-glucosyl-indol-3-yl formamide (4OGlcI3F) as a pathogen-inducible, tryptophan-derived compound that overaccumulates in pen3 leaf tissue and has biosynthesis that is dependent on an intact PEN2 metabolic pathway. We propose that a precursor of 4OGlcI3F is the PEN3 substrate in extracellular pathogen defense. These precursors, the shared indole core present in IBA and 4OGlcI3F, and allele-specific uncoupling of a subset of PEN3 functions suggest that PEN3 transports distinct indole-type metabolites in distinct biological processes. PMID:26023163

  6. MASTR: A Technique for Mosaic Mutant Analysis with Spatial and Temporal Control of Recombination Using Conditional Floxed Alleles in Mice

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    Zhimin Lao

    2012-08-01

    Full Text Available Mosaic mutant analysis, the study of cellular defects in scattered mutant cells in a wild-type environment, is a powerful approach for identifying critical functions of genes and has been applied extensively to invertebrate model organisms. A highly versatile technique has been developed in mouse: MASTR (mosaic mutant analysis with spatial and temporal control of recombination, which utilizes the increasing number of floxed alleles and simultaneously combines conditional gene mutagenesis and cell marking for fate analysis. A targeted allele (R26MASTR was engineered; the allele expresses a GFPcre fusion protein following FLP-mediated recombination, which serves the dual function of deleting floxed alleles and marking mutant cells with GFP. Within 24 hr of tamoxifen administration to R26MASTR mice carrying an inducible FlpoER transgene and a floxed allele, nearly all GFP-expressing cells have a mutant allele. The fate of single cells lacking FGF8 or SHH signaling in the developing hindbrain was analyzed using MASTR, and it was revealed that there is only a short time window when neural progenitors require FGFR1 for viability and that granule cell precursors differentiate rapidly when SMO is lost. MASTR is a powerful tool that provides cell-type-specific (spatial and temporal marking of mosaic mutant cells and is broadly applicable to developmental, cancer, and adult stem cell studies.

  7. The late flowering phenotype of fwa mutants is caused by gain-of-function epigenetic alleles of a homeodomain gene

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    Soppe, W.J.J.; Jacobsen, S.E.; Alonso-Blanco, C.; Jackson, J.P.; Kakutani, T.; Koornneef, M.; Peeters, A.J.M.

    2000-01-01

    The transition to flowering in Arabidopsis thaliana is delayed in fwa mutant plants. FWA was identified by loss-of-function mutations in normally flowering revertants of the fwa mutant, and it encodes a homeodomain-containing transcription factor. The DNA sequence of wild-type and fwa mutant alleles

  8. Molecular analysis of mutant and wild type alcohol dehydrogenase alleles from Drosophila

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    Batzer, M.A.

    1988-01-01

    Wild type alcohol dehydrogenase polypeptides (ADH) from Drosophila melanogaster transformants were examined using western blots and polyclonal antiserum specific for Drosophila melanogaster ADH. Mutants induced in Drosophila spermatozoa at the alcohol dehydrogenase (Adh) locus using X-rays, 1-ethyl-1-nitrosourea (ENU) or ethyl methanesulfonate (EMS) were characterized using genetic complementation tests, western blots, Southern blots, northern blots and enzymatic amplification of the Adh locus. Genetic complementation tests showed that 22/30 X-ray-induced mutants, and 3/13 ENU and EMS induced mutants were multi-locus deficiencies. Western blot analysis of the intragenic mutations showed that 4/7 X-ray-induced mutants produced detectable polypeptides, one of which was normal in molecular weight and charge. In contrast 8/10 intragenic ENU and EMS induced mutants produced normal polypeptides. Southern blot analysis showed that 5/7 intragenic X-ray induced mutants and all 10 of the intragenic ENU and EMS induced mutants were normal with respect to the alleles they were derived from

  9. Marker-Assisted Selection for Recognizing Wheat Mutant Genotypes Carrying HMW Glutenin Alleles Related to Baking Quality

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    Mohammad Javad Zamani

    2014-01-01

    Full Text Available Allelic diversity of HMW glutenin loci in several studies revealed that allelic combinations affect dough quality. Dx5 + Dy10 subunits are related to good baking quality and Dx2 + Dy12 are related to undesirable baking quality. One of the most regular methods to evaluate the baking quality is SDS-PAGE which is used to improve baking quality labs. Marker-assisted selection is the method which can recognize the alleles related to baking quality and this method is based on polymerase chain reaction. 10 pairs of specific primers related to Dx2, Dx2.1, Dx5, Dy10, and Dy12 subunits were used for recognizing baking quality of some wheat varieties and some mutant genotypes. Only 5 pairs of them could show the specific bands. All subunits were recognized by the primers except Dx2.1. Some of the primers were extracted from previous studies and the others were designed based on D genome subunits of wheat. SDS-PAGE method accomplished having confidence in these marker’s results. To realize the effect of mutation, seed storage proteins were measured. It showed that mutation had effect on the amount of seed storage protein on the mutant seeds (which showed polymorphism.

  10. Marker-assisted selection for recognizing wheat mutant genotypes carrying HMW glutenin alleles related to baking quality.

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    Zamani, Mohammad Javad; Bihamta, Mohammad Reza; Naserian Khiabani, Behnam; Tahernezhad, Zahra; Hallajian, Mohammad Taher; Shamsi, Marzieh Varasteh

    2014-01-01

    Allelic diversity of HMW glutenin loci in several studies revealed that allelic combinations affect dough quality. Dx5 + Dy10 subunits are related to good baking quality and Dx2 + Dy12 are related to undesirable baking quality. One of the most regular methods to evaluate the baking quality is SDS-PAGE which is used to improve baking quality labs. Marker-assisted selection is the method which can recognize the alleles related to baking quality and this method is based on polymerase chain reaction. 10 pairs of specific primers related to Dx2, Dx2.1, Dx5, Dy10, and Dy12 subunits were used for recognizing baking quality of some wheat varieties and some mutant genotypes. Only 5 pairs of them could show the specific bands. All subunits were recognized by the primers except Dx2.1. Some of the primers were extracted from previous studies and the others were designed based on D genome subunits of wheat. SDS-PAGE method accomplished having confidence in these marker's results. To realize the effect of mutation, seed storage proteins were measured. It showed that mutation had effect on the amount of seed storage protein on the mutant seeds (which showed polymorphism).

  11. Characterization of a New Pink-Fruited Tomato Mutant Results in the Identification of a Null Allele of the SlMYB12 Transcription Factor.

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    Fernandez-Moreno, Josefina-Patricia; Tzfadia, Oren; Forment, Javier; Presa, Silvia; Rogachev, Ilana; Meir, Sagit; Orzaez, Diego; Aharoni, Aspah; Granell, Antonio

    2016-07-01

    The identification and characterization of new tomato (Solanum lycopersicum) mutants affected in fruit pigmentation and nutritional content can provide valuable insights into the underlying biology, as well as a source of new alleles for breeding programs. To date, all characterized pink-pigmented tomato fruit mutants appear to result from low SlMYB12 transcript levels in the fruit skin. Two new mutant lines displaying a pink fruit phenotype (pf1 and pf2) were characterized in this study. In the pf mutants, SlMYB12 transcripts accumulated to wild-type levels but exhibited the same truncation, which resulted in the absence of the essential MYB activation domain coding region. Allelism and complementation tests revealed that both pf mutants were allelic to the y locus and showed the same recessive null allele in homozygosis: Δy A set of molecular and metabolic effects, reminiscent of those observed in the Arabidopsis (Arabidopsis thaliana) myb11 myb12 myb111 triple mutant, were found in the tomato Δy mutants. To our knowledge, these have not been described previously, and our data support the idea of their being null mutants, in contrast to previously described transcriptional hypomorphic pink fruit lines. We detected a reduction in the expression of several flavonol glycosides and some associated glycosyl transferases. Transcriptome analysis further revealed that the effects of the pf mutations extended beyond the flavonoid pathway into the interface between primary and secondary metabolism. Finally, screening for Myb-binding sites in the candidate gene promoter sequences revealed that 141 of the 152 co-down-regulated genes may be direct targets of SlMYB12 regulation. © 2016 American Society of Plant Biologists. All Rights Reserved.

  12. Specific Silencing of L392V PSEN1 Mutant Allele by RNA Interference

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    Malgorzata Sierant

    2011-01-01

    Full Text Available RNA interference (RNAi technology provides a powerful molecular tool to reduce an expression of selected genes in eukaryotic cells. Short interfering RNAs (siRNAs are the effector molecules that trigger RNAi. Here, we describe siRNAs that discriminate between the wild type and mutant (1174 C→G alleles of human Presenilin1 gene (PSEN1. This mutation, resulting in L392V PSEN1 variant, contributes to early onset familial Alzheimer's disease. Using the dual fluorescence assay, flow cytometry and fluorescent microscopy we identified positions 8th–11th, within the central part of the antisense strand, as the most sensitive to mismatches. 2-Thiouridine chemical modification introduced at the 3′-end of the antisense strand improved the allele discrimination, but wobble base pairing adjacent to the mutation site abolished the siRNA activity. Our data indicate that siRNAs can be designed to discriminate between the wild type and mutant alleles of genes that differ by just a single nucleotide.

  13. Quantitative threefold allele-specific PCR (QuanTAS-PCR) for highly sensitive JAK2 V617F mutant allele detection

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    Zapparoli, Giada V; Jorissen, Robert N; Hewitt, Chelsee A; McBean, Michelle; Westerman, David A; Dobrovic, Alexander

    2013-01-01

    The JAK2 V617F mutation is the most frequent somatic change in myeloproliferative neoplasms, making it an important tumour-specific marker for diagnostic purposes and for the detection of minimal residual disease. Sensitive quantitative assays are required for both applications, particularly for the monitoring of minimal residual disease, which requires not only high sensitivity but also very high specificity. We developed a highly sensitive probe-free quantitative mutant-allele detection method, Quantitative Threefold Allele-Specific PCR (QuanTAS-PCR), that is performed in a closed-tube system, thus eliminating the manipulation of PCR products. QuantTAS-PCR uses a threefold approach to ensure allele-specific amplification of the mutant sequence: (i) a mutant allele-specific primer, (ii) a 3′dideoxy blocker to suppress false-positive amplification from the wild-type template and (iii) a PCR specificity enhancer, also to suppress false-positive amplification from the wild-type template. Mutant alleles were quantified relative to exon 9 of JAK2. We showed that the addition of the 3′dideoxy blocker suppressed but did not eliminate false-positive amplification from the wild-type template. However, the addition of the PCR specificity enhancer near eliminated false-positive amplification from the wild-type allele. Further discrimination between true and false positives was enabled by using the quantification cycle (Cq) value of a single mutant template as a cut-off point, thus enabling robust distinction between true and false positives. As 10,000 JAK2 templates were used per replicate, the assay had a sensitivity of 1/10 -4 per replicate. Greater sensitivity could be reached by increasing the number of replicates analysed. Variation in replicates when low mutant-allele templates were present necessitated the use of a statistics-based approach to estimate the load of mutant JAK2 copies. QuanTAS-PCR showed comparable quantitative results when validated against a

  14. Hearing loss associated with enlarged vestibular aqueduct and zero or one mutant allele of SLC26A4.

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    Rose, Jane; Muskett, Julie A; King, Kelly A; Zalewski, Christopher K; Chattaraj, Parna; Butman, John A; Kenna, Margaret A; Chien, Wade W; Brewer, Carmen C; Griffith, Andrew J

    2017-07-01

    To characterize the severity and natural history of hearing loss, and the prevalence of having a cochlear implant in a maturing cohort of individuals with enlarged vestibular aqueduct (EVA) and zero or one mutant allele of SLC26A4. Prospective cohort study of subjects ascertained between 1998 and 2015 at the National Institutes of Health Clinical Center. Study subjects were 127 individuals (median age, 8 years; range, 0-59 years) with EVA in at least one ear. Ears with EVA and zero or one mutant allele of SLC26A4 had mean 0.5/1/2/4-kHz pure-tone averages of 62.6 and 52.9 dB HL, respectively, in contrast to EVA ears with two mutant alleles of SLC26A4 (88.1 dB HL; P zero, one, and two mutant alleles, respectively (P = .00833). This association was not independent (P = .534) but reflected underlying correlations with age at time of first audiogram (P = .003) or severity of hearing loss (P = .000). Ears with EVA and zero or one mutant allele of SLC26A4 have less severe hearing loss, no difference in prevalence of fluctuation, and a lower prevalence of cochlear implantation in comparison to ears with two mutant alleles of SLC26A4. NA Laryngoscope, 127:E238-E243, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  15. Paternal or Maternal Uniparental Disomy of Chromosome 16 Resulting in Homozygosity of a Mutant Allele Causes Fanconi Anemia.

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    Donovan, Frank X; Kimble, Danielle C; Kim, Yonghwan; Lach, Francis P; Harper, Ursula; Kamat, Aparna; Jones, MaryPat; Sanborn, Erica M; Tryon, Rebecca; Wagner, John E; MacMillan, Margaret L; Ostrander, Elaine A; Auerbach, Arleen D; Smogorzewska, Agata; Chandrasekharappa, Settara C

    2016-05-01

    Fanconi anemia (FA) is a rare inherited disorder caused by pathogenic variants in one of 19 FANC genes. FA patients display congenital abnormalities, and develop bone marrow failure, and cancer susceptibility. We identified homozygous mutations in four FA patients and, in each case, only one parent carried the obligate mutant allele. FANCA and FANCP/SLX4 genes, both located on chromosome 16, were the affected recessive FA genes in three and one family respectively. Genotyping with short tandem repeat markers and SNP arrays revealed uniparental disomy (UPD) of the entire mutation-carrying chromosome 16 in all four patients. One FANCA patient had paternal UPD, whereas FA in the other three patients resulted from maternal UPD. These are the first reported cases of UPD as a cause of FA. UPD indicates a reduced risk of having another child with FA in the family and has implications in prenatal diagnosis. © 2016 WILEY PERIODICALS, INC.

  16. Frequency of the MDR1 mutant allele associated with multidrug sensitivity in dogs from Brazil

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    Monobe MM

    2015-04-01

    Full Text Available Marina M Monobe,1 João P Araujo Junior,2 Kari V Lunsford,3 Rodrigo C Silva,4 Camilo Bulla41Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, 2Department of Microbiology and Immunology, Biosciences Institute, Sao Paulo State University (UNESP, Botucatu, Brazil; 3Department of Clinical Sciences and Animal Health Center, 4Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi, MS, USAAbstract: To date, a 4-bp deletion in the MDR1 gene has been detected in more than ten dog breeds, as well as in mixed breed dogs, in several countries, however information regarding this mutation in dogs from Brazil is lacking. For this reason, 103 Collies, 77 Border Collies, 76 Shetland Sheepdogs, 20 Old English Sheepdogs, 55 German Shepherds, 16 Australian Shepherds, and 53 Whippets from Brazil were screened for the presence of the mutation. The heterozygous mutated genotype, MDR1 (+/−, frequency found for Collies, Australian Shepherd, and Shetland Sheepdog was 50.5% (95% CI =41.1%–59.9%, 31.3% (95% CI =8.6%–53.2%, and 15.8% (95% CI =7.7%–23.9%, respectively. Homozygous mutated genotype, MDR1 (−/−, was detected only in Collies 35.9%. The MDR1 allele mutant frequency found for Collies, Australian Shepherd, and Shetland Sheepdog was 61.2% (95% CI =54.8%–67.5%, 15.6% (95% CI =3.1%–28.2%, and 7.9% (95% CI =3.7%–12.1%, respectively. Additionally, even free of the mutant allele, the maximum mutant prevalence (MMP in that population, with 95% CI, was 3.8%, 5.2%, 5.4%, and 13.8% for Border Collies, German Shepherds, Whippets, and Old English Sheepdogs, respectively. In this way, this information is important, not only for MDR1 genotype-based breeding programs and international exchange of breeding animals of predisposed breeds, but also for modification of drug therapy for breeds at risk.Keywords: P-glycoprotein, MDR1 mutation, ivermectin, dog, drug

  17. Allele-specific Gene Silencing of Mutant mRNA Restores Cellular Function in Ullrich Congenital Muscular Dystrophy Fibroblasts

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    Satoru Noguchi

    2014-01-01

    Full Text Available Ullrich congenital muscular dystrophy (UCMD is an inherited muscle disorder characterized clinically by muscle weakness, distal joint hyperlaxity, and proximal joint contractures. Sporadic and recessive mutations in the three collagen VI genes, COL6A1, COL6A2, and COL6A3, are reported to be causative. In the sporadic forms, a heterozygous point mutation causing glycine substitution in the triple helical domain has been identified in higher rate. In this study, we examined the efficacy of siRNAs, which target point mutation site, on specific knockdown toward transcripts from mutant allele and evaluated consequent cellular phenotype of UCMD fibroblasts. We evaluated the effect of siRNAs targeted to silence-specific COL6A1 alleles in UCMD fibroblasts, where simultaneous expression of both wild-type and mutant collagen VI resulted in defective collagen localization. Addition of mutant-specific siRNAs allowed normal extracellular localization of collagen VI surrounding fibroblasts, suggesting selective inhibition of mutant collagen VI. Targeting the single-nucleotide COL6A1 c.850G>A (p.G284R mutation responsible a sporadic autosomal dominant form of UCMD can potently and selectively block expression of mutant collagen VI. These results suggest that allele-specific knockdown of the mutant mRNA can potentially be considered as a therapeutic procedure in UCMD due to COL6A1 point mutations.

  18. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 1. Chlorophyll Mutations in Allelic tw Mutants and Their Revertants

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    Vaitkuniene, V.

    1995-01-01

    Genotypical environment is an essential factor determining the mutability of mutants of the same type. Decreased chlorophyll mutant frequency was a common characteristic of all tested tw type (tw, tw 1 , tw 2 ) mutants induced in barley c. 'Auksiniai II'. The mutability of all the tested revertants was close to that of the initial c. 'Auksiniai II'. (author). 9 refs., 2 tabs

  19. Efficient Identification of Causal Mutations through Sequencing of Bulked F2 from Two Allelic Bloomless Mutants of Sorghum bicolor

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    Yinping Jiao

    2018-01-01

    Full Text Available Sorghum (Sorghum bicolor Moench, L. plant accumulates copious layers of epi-cuticular wax (EW on its aerial surfaces, to a greater extent than most other crops. EW provides a vapor barrier that reduces water loss, and is therefore considered to be a major determinant of sorghum's drought tolerance. However, little is known about the genes responsible for wax accumulation in sorghum. We isolated two allelic mutants, bloomless40-1 (bm40-1 and bm40-2, from a mutant library constructed from ethyl methane sulfonate (EMS treated seeds of an inbred, BTx623. Both mutants were nearly devoid of the EW layer. Each bm mutant was crossed to the un-mutated BTx623 to generated F2 populations that segregated for the bm phenotype. Genomic DNA from 20 bm F2 plants from each population was bulked for whole genome sequencing. A single gene, Sobic.001G228100, encoding a GDSL-like lipase/acylhydrolase, had unique homozygous mutations in each bulked F2 population. Mutant bm40-1 harbored a missense mutation in the gene, whereas bm40-2 had a splice donor site mutation. Our findings thus provide strong evidence that mutation in this GDSL-like lipase gene causes the bm phenotype, and further demonstrate that this approach of sequencing two independent allelic mutant populations is an efficient method for identifying causal mutations. Combined with allelic mutants, MutMap provides powerful method to identify all causal genes for the large collection of bm mutants in sorghum, which will provide insight into how sorghum plants accumulate such abundant EW on their aerial surface. This knowledge may facilitate the development of tools for engineering drought-tolerant crops with reduced water loss.

  20. Analysis of Yellow Striped Mutants of Zea mays Reveals Novel Loci Contributing to Iron Deficiency Chlorosis

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    David Chan-Rodriguez

    2018-02-01

    Full Text Available The micronutrient iron (Fe is essential for photosynthesis, respiration, and many other processes, but it is only sparingly soluble in aqueous solution, making adequate acquisition by plants a serious challenge. Fe is a limiting factor for plant growth on approximately 30% of the world’s arable lands. Moreover, Fe deficiency in humans is a global health issue, affecting 1.62 billion people, or about 25% of the world’s population. It is imperative that we gain a better understanding of the mechanisms that plants use to regulate iron homeostasis, since these will be important targets for future biofortification and crop improvement strategies. Grasses and non-grasses have evolved independent mechanisms for primary iron uptake from the soil. The grasses, which include most of the world’s staple grains, have evolved a distinct ‘chelation’ mechanism to acquire iron from the soil. Strong iron chelators called phytosiderophores (PSs are synthesized by grasses and secreted into the rhizosphere where they bind and solubilize Fe(III. The Fe(III-PS complex is then taken up into root cells via transporters specific for the Fe(III-PS complex. In this study, 31 novel, uncharacterized striped maize mutants available through the Maize Genetics Cooperation Stock Center (MGCSC were analyzed to determine whether their mutant phenotypes are caused by decreased iron. Many of these proved to be either pale yellow or white striped mutants. Complementation tests were performed by crossing the MGCSC mutants to ys1 and ys3 reference mutants. This allowed assignment of 10 ys1 alleles and 4 ys3 alleles among the novel mutants. In addition, four ys∗ mutant lines were identified that are not allelic to either ys1 or ys3. Three of these were characterized as being non-allelic to each other and as having low iron in leaves. These represent new genes involved in iron acquisition by maize, and future cloning of these genes may reveal novel aspects of the grass iron

  1. A mutant crp allele that differentially activates the operons of the fuc regulon in Escherichia coli.

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    Zhu, Y; Lin, E C

    1988-05-01

    L-Fucose is used by Escherichia coli through an inducible pathway mediated by a fucP-encoded permease, a fucI-encoded isomerase, a fucK-encoded kinase, and a fucA-encoded aldolase. The adolase catalyzes the formation of dihydroxyacetone phosphate and L-lactaldehyde. Anaerobically, lactaldehyde is converted by a fucO-encoded oxidoreductase to L-1,2-propanediol, which is excreted. The fuc genes belong to a regulon comprising four linked operons: fucO, fucA, fucPIK, and fucR. The positive regulator encoded by fucR responds to fuculose 1-phosphate as the effector. Mutants serially selected for aerobic growth on propanediol became constitutive in fucO and fucA [fucO(Con) fucA(Con)], but noninducible in fucPIK [fucPIK(Non)]. An external suppressor mutation that restored growth on fucose caused constitutive expression of fucPIK. Results from this study indicate that this suppressor mutation occurred in crp, which encodes the cyclic AMP-binding (or receptor) protein. When the suppressor allele (crp-201) was transduced into wild-type strains, the recipient became fucose negative and fucose sensitive (with glycerol as the carbon and energy source) because of impaired expression of fucA. The fucPIK operon became hyperinducible. The growth rate on maltose was significantly reduced, but growth on L-rhamnose, D-galactose, L-arabinose, glycerol, or glycerol 3-phosphate was close to normal. Lysogenization of fuc+ crp-201 cells by a lambda bacteriophage bearing crp+ restored normal growth ability on fucose. In contrast, lysogenization of [fucO(Con)fucA(Con)fucPIK(Non)crp-201] cells by the same phage retarded their growth on fucose.

  2. Marker-Assisted Selection for Recognizing Wheat Mutant Genotypes Carrying HMW Glutenin Alleles Related to Baking Quality

    OpenAIRE

    Zamani, Mohammad Javad; Bihamta, Mohammad Reza; Naserian Khiabani, Behnam; Tahernezhad, Zahra; Hallajian, Mohammad Taher; Shamsi, Marzieh Varasteh

    2014-01-01

    Allelic diversity of HMW glutenin loci in several studies revealed that allelic combinations affect dough quality. Dx5 + Dy10 subunits are related to good baking quality and Dx2 + Dy12 are related to undesirable baking quality. One of the most regular methods to evaluate the baking quality is SDS-PAGE which is used to improve baking quality labs. Marker-assisted selection is the method which can recognize the alleles related to baking quality and this method is based on polymerase chain reac...

  3. Allele-Specific DNA Methylation and Its Interplay with Repressive Histone Marks at Promoter-Mutant TERT Genes

    Directory of Open Access Journals (Sweden)

    Josh Lewis Stern

    2017-12-01

    Full Text Available A mutation in the promoter of the Telomerase Reverse Transcriptase (TERT gene is the most frequent noncoding mutation in cancer. The mutation drives unusual monoallelic expression of TERT, allowing immortalization. Here, we find that DNA methylation of the TERT CpG island (CGI is also allele-specific in multiple cancers. The expressed allele is hypomethylated, which is opposite to cancers without TERT promoter mutations. The continued presence of Polycomb repressive complex 2 (PRC2 on the inactive allele suggests that histone marks of repressed chromatin may be causally linked to high DNA methylation. Consistent with this hypothesis, TERT promoter DNA containing 5-methyl-CpG has much increased affinity for PRC2 in vitro. Thus, CpG methylation and histone marks appear to collaborate to maintain the two TERT alleles in different epigenetic states in TERT promoter mutant cancers. Finally, in several cancers, DNA methylation levels at the TERT CGI correlate with altered patient survival.

  4. Allele-Specific DNA Methylation and Its Interplay with Repressive Histone Marks at Promoter-Mutant TERT Genes.

    Science.gov (United States)

    Stern, Josh Lewis; Paucek, Richard D; Huang, Franklin W; Ghandi, Mahmoud; Nwumeh, Ronald; Costello, James C; Cech, Thomas R

    2017-12-26

    A mutation in the promoter of the Telomerase Reverse Transcriptase (TERT) gene is the most frequent noncoding mutation in cancer. The mutation drives unusual monoallelic expression of TERT, allowing immortalization. Here, we find that DNA methylation of the TERT CpG island (CGI) is also allele-specific in multiple cancers. The expressed allele is hypomethylated, which is opposite to cancers without TERT promoter mutations. The continued presence of Polycomb repressive complex 2 (PRC2) on the inactive allele suggests that histone marks of repressed chromatin may be causally linked to high DNA methylation. Consistent with this hypothesis, TERT promoter DNA containing 5-methyl-CpG has much increased affinity for PRC2 in vitro. Thus, CpG methylation and histone marks appear to collaborate to maintain the two TERT alleles in different epigenetic states in TERT promoter mutant cancers. Finally, in several cancers, DNA methylation levels at the TERT CGI correlate with altered patient survival. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  5. Matching NLR Immune Receptors to Autoimmunity in camta3 Mutants Using Antimorphic NLR Alleles

    DEFF Research Database (Denmark)

    Lolle, Signe; Greeff, Christiaan; Petersen, Klaus

    2017-01-01

    result from inappropriate NLR activation because mutations in plant guardees could trigger corresponding NLR guards. To explore these hypotheses, we expressed 108 dominant-negative (DN) Arabidopsis NLRs in various lesion mimic mutants, including camta3, which exhibits autoimmunity. CAMTA3 was previously...

  6. BRAF Gene Copy Number and Mutant Allele Frequency Correlate with Time to Progression in Metastatic Melanoma Patients Treated with MAPK Inhibitors.

    Science.gov (United States)

    Stagni, Camilla; Zamuner, Carolina; Elefanti, Lisa; Zanin, Tiziana; Bianco, Paola Del; Sommariva, Antonio; Fabozzi, Alessio; Pigozzo, Jacopo; Mocellin, Simone; Montesco, Maria Cristina; Chiarion-Sileni, Vanna; De Nicolo, Arcangela; Menin, Chiara

    2018-06-01

    Metastatic melanoma is characterized by complex genomic alterations, including a high rate of mutations in driver genes and widespread deletions and amplifications encompassing various chromosome regions. Among them, chromosome 7 is frequently gained in BRAF -mutant melanoma, inducing a mutant allele-specific imbalance. Although BRAF amplification is a known mechanism of acquired resistance to therapy with MAPK inhibitors, it is still unclear if BRAF copy-number variation and BRAF mutant allele imbalance at baseline can be associated with response to treatment. In this study, we used a multimodal approach to assess BRAF copy number and mutant allele frequency in pretreatment melanoma samples from 46 patients who received MAPK inhibitor-based therapy, and we analyzed the association with progression-free survival. We found that 65% patients displayed BRAF gains, often supported by chromosome 7 polysomy. In addition, we observed that 64% patients had a balanced BRAF -mutant/wild-type allele ratio, whereas 14% and 23% patients had low and high BRAF mutant allele frequency, respectively. Notably, a significantly higher risk of progression was observed in patients with a diploid BRAF status versus those with BRAF gains [HR, 2.86; 95% confidence interval (CI), 1.29-6.35; P = 0.01] and in patients with low percentage versus those with a balanced BRAF mutant allele percentage (HR, 4.54; 95% CI, 1.33-15.53; P = 0.016). Our data suggest that quantitative analysis of the BRAF gene could be useful to select the melanoma patients who are most likely to benefit from therapy with MAPK inhibitors. Mol Cancer Ther; 17(6); 1332-40. ©2018 AACR . ©2018 American Association for Cancer Research.

  7. The Impact of Collisions on the Ability to Detect Rare Mutant Alleles Using Barcode-Type Next-Generation Sequencing Techniques

    Directory of Open Access Journals (Sweden)

    Jenna VanLiere Canzoniero

    2017-07-01

    Full Text Available Barcoding techniques are used to reduce error from next-generation sequencing, with applications ranging from understanding tumor subclone populations to detecting circulating tumor DNA. Collisions occur when more than one sample molecule is tagged by the same unique identifier (UID and can result in failure to detect very-low-frequency mutations and error in estimating mutation frequency. Here, we created computer models of barcoding technique, with and without amplification bias introduced by the UID, and analyzed the effect of collisions for a range of mutant allele frequencies (1e−6 to 0.2, number of sample molecules (10 000 to 1e7, and number of UIDs (4 10 -4 14 . Inability to detect rare mutant alleles occurred in 0% to 100% of simulations, depending on collisions and number of mutant molecules. Collisions also introduced error in estimating mutant allele frequency resulting in underestimation of minor allele frequency. Incorporating an understanding of the effect of collisions into experimental design can allow for optimization of the number of sample molecules and number of UIDs to minimize the negative impact on rare mutant detection and mutant frequency estimation.

  8. [Double mutant alleles in the EXT1 gene not previously reported in a teenager with hereditary multiple exostoses].

    Science.gov (United States)

    Cammarata-Scalisi, Francisco; Cozar, Mónica; Grinberg, Daniel; Balcells, Susana; Asteggiano, Carla G; Martínez-Domenech, Gustavo; Bracho, Ana; Sánchez, Yanira; Stock, Frances; Delgado-Luengo, Wilmer; Zara-Chirinos, Carmen; Chacín, José Antonio

    2015-04-01

    Hereditary forms of multiple exostoses, now called EXT1/EXT2-CDG within Congenital Disorders of Glycosylation, are the most common benign bone tumors in humans and clinical description consists of the formation of several cartilage-capped bone tumors, usually benign and localized in the juxta-epiphyseal region of long bones, although wide body dissemination in severe cases is not uncommon. Onset of the disease is variable ranging from 2-3 years up to 13-15 years with an estimated incidence ranging from 1/18,000 to 1/50,000 cases in European countries. We present a double mutant alleles in the EXT1 gene not previously reported in a teenager and her family with hereditary multiple exostoses.

  9. Characterization of a new full length TMPRSS3 isoform and identification of mutant alleles responsible for nonsyndromic recessive deafness in Newfoundland and Pakistan

    Directory of Open Access Journals (Sweden)

    Shotland Lawrence I

    2004-09-01

    Full Text Available Abstract Background Mutant alleles of TMPRSS3 are associated with nonsyndromic recessive deafness (DFNB8/B10. TMPRSS3 encodes a predicted secreted serine protease, although the deduced amino acid sequence has no signal peptide. In this study, we searched for mutant alleles of TMPRSS3 in families from Pakistan and Newfoundland with recessive deafness co-segregating with DFNB8/B10 linked haplotypes and also more thoroughly characterized the genomic structure of TMPRSS3. Methods We enrolled families segregating recessive hearing loss from Pakistan and Newfoundland. Microsatellite markers flanking the TMPRSS3 locus were used for linkage analysis. DNA samples from participating individuals were sequenced for TMPRSS3. The structure of TMPRSS3 was characterized bioinformatically and experimentally by sequencing novel cDNA clones of TMPRSS3. Results We identified mutations in TMPRSS3 in four Pakistani families with recessive, nonsyndromic congenital deafness. We also identified two recessive mutations, one of which is novel, of TMPRSS3 segregating in a six-generation extended family from Newfoundland. The spectrum of TMPRSS3 mutations is reviewed in the context of a genotype-phenotype correlation. Our study also revealed a longer isoform of TMPRSS3 with a hitherto unidentified exon encoding a signal peptide, which is expressed in several tissues. Conclusion Mutations of TMPRSS3 contribute to hearing loss in many communities worldwide and account for 1.8% (8 of 449 of Pakistani families segregating congenital deafness as an autosomal recessive trait. The newly identified TMPRSS3 isoform e will be helpful in the functional characterization of the full length protein.

  10. Real-time PCR genotyping assay for canine progressive rod-cone degeneration and mutant allele frequency in Toy Poodles, Chihuahuas and Miniature Dachshunds in Japan.

    Science.gov (United States)

    Kohyama, Moeko; Tada, Naomi; Mitsui, Hiroko; Tomioka, Hitomi; Tsutsui, Toshihiko; Yabuki, Akira; Rahman, Mohammad Mahbubur; Kushida, Kazuya; Mizukami, Keijiro; Yamato, Osamu

    2016-03-01

    Canine progressive rod-cone degeneration (PRCD) is a middle- to late-onset, autosomal recessive, inherited retinal disorder caused by a substitution (c.5G>A) in the canine PRCD gene that has been identified in 29 or more purebred dogs. In the present study, a TaqMan probe-based real-time PCR assay was developed and evaluated for rapid genotyping and large-scale screening of the mutation. Furthermore, a genotyping survey was carried out in a population of the three most popular breeds in Japan (Toy Poodles, Chihuahuas and Miniature Dachshunds) to determine the current mutant allele frequency. The assay separated all the genotypes of canine PRCD rapidly, indicating its suitability for large-scale surveys. The results of the survey showed that the mutant allele frequency in Toy Poodles was high enough (approximately 0.09) to allow the establishment of measures for the prevention and control of this disorder in breeding kennels. The mutant allele was detected in Chihuahuas for the first time, but the frequency was lower (approximately 0.02) than that in Toy Poodles. The mutant allele was not detected in Miniature Dachshunds. This assay will allow the selective breeding of dogs from the two most popular breeds (Toy Poodle and Chihuahua) in Japan and effective prevention or control of the disorder.

  11. Complex mosaic CDKL5 deletion with two distinct mutant alleles in a 4-year-old girl.

    Science.gov (United States)

    Boutry-Kryza, Nadia; Ville, Dorothée; Labalme, Audrey; Calender, Alain; Dupont, Jean-Michel; Touraine, Renaud; Edery, Patrick; des Portes, Vincent; Sanlaville, Damien; Lesca, Gaetan

    2014-08-01

    Mutations of the CDKL5 gene cause early epileptic encephalopathy. Patients manifest refractory epilepsy, beginning before the age of 3 months, which is associated with severe psychomotor delay and features that overlap with Rett syndrome. We report here a patient with mosaicism for CDKL5 exonic deletion, with the presence of two mutant alleles. The affected 4-year-old girl presented with infantile spasms, beginning at the age of 9 months, but subsequent progression of the disease was consistent with the classical CDKL5-related phenotype. A deletion of exons 17 and 18 was suspected on the basis of Multiplex Ligation Probe Amplification analysis, but unexpected results for cDNA analysis, which showed the presence of an abnormal transcript with the deletion of exon 18 only, led us to suspect that two distinct events might have occurred. We used custom array-CGH to determine the size and breakpoints of these deletions. Exon 18 was deleted from one of the abnormal alleles, and exon 17 was deleted from the other. A Fork Stalling and Template Switching (FoSTeS) mechanism was proposed to explain the two events, given the presence of regions of microhomology at the breakpoints. We propose here an original involvement of the FoSTeS mechanism to explain the co-occurrence of these two events in the CDKL5 gene in a single patient. This patient highlights the difficulties involved in the detection of such abnormalities, particularly when they occur in a mosaic state and involve two distinct mutational events in a single gene. © 2014 Wiley Periodicals, Inc.

  12. Production of a Marfan cellular phenotype by expressing a mutant human fibrillin allele on a normal human or murine genetic background

    Energy Technology Data Exchange (ETDEWEB)

    Eldadah, Z.A.; Dietz, H.C. [Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States); Brenn, T. [Stanford Univ. Medical Center, CA (United States)] [and others

    1994-09-01

    The Marfan Syndrome (MFS) is a heritable disorder of connective tissue caused by defects in fibrillin (FBN1), a 350 kD glycoprotein and principal component of the extracellular microfibril. Previous correlations of mutant transcript level and disease severity suggested a dominant negative model of MFS pathogenesis. To address this hypothesis we assembled an expression construct containing the mutant allele from a patient with severe MFS. This mutation causes skipping of FBN1 exon 2 and a frame shift, leading to a premature termination codon in exon 4. The predicted peptide would thus consist of 55 wild type and 45 missense amino acids. The construct was stably transfected into cultured human and mouse fibroblasts, and several clonal cell populations were established. Human and mouse cells expressing the truncated peptide exhibited markedly diminished fibrillin deposition and disorganized microfibrillar architecture by immunofluorescence. Pulse-chase analysis of these cells demonstrated normal levels of fibrillin synthesis but substantially decreased fibrillin deposition into the extracellular matrix. These data illustrate that expression of a mutant FBN1 allele, on a background of two normal alleles, is sufficient to disrupt normal fibrillin aggregation and reproduce the MFS cellular phenotype. This provides confirmation of a dominant negative model of MFS pathogenesis and may offer mutant allele knockout as a strategy for gene therapy. In addition, these data underscore the importance of the FBN1 amino-terminus in normal multimer formation and suggest that expression of the human extreme 5{prime} FBN1 coding sequence may be sufficient, in isolation, to produce an animal model of MFS. Indeed, transgenic mice harboring this mutant allele have been produced, and phenotype analysis is currently in progress.

  13. Allosteric Mutant IDH1 Inhibitors Reveal Mechanisms for IDH1 Mutant and Isoform Selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xiaoling; Baird, Daniel; Bowen, Kimberly; Capka, Vladimir; Chen, Jinyun; Chenail, Gregg; Cho, YoungShin; Dooley, Julia; Farsidjani, Ali; Fortin, Pascal; Kohls, Darcy; Kulathila, Raviraj; Lin, Fallon; McKay, Daniel; Rodrigues, Lindsey; Sage, David; Touré, B. Barry; van der Plas, Simon; Wright, Kirk; Xu, Ming; Yin, Hong; Levell, Julian; Pagliarini, Raymond A. (Novartis)

    2017-03-01

    Oncogenic IDH1 and IDH2 mutations contribute to cancer via production of R-2-hydroxyglutarate (2-HG). Here, we characterize two structurally distinct mutant- and isoform-selective IDH1 inhibitors that inhibit 2-HG production. Both bind to an allosteric pocket on IDH1, yet shape it differently, highlighting the plasticity of this site. Oncogenic IDH1R132H mutation destabilizes an IDH1 “regulatory segment,” which otherwise restricts compound access to the allosteric pocket. Regulatory segment destabilization in wild-type IDH1 promotes inhibitor binding, suggesting that destabilization is critical for mutant selectivity. We also report crystal structures of oncogenic IDH2 mutant isoforms, highlighting the fact that the analogous segment of IDH2 is not similarly destabilized. This intrinsic stability of IDH2 may contribute to observed inhibitor IDH1 isoform selectivity. Moreover, discrete residues in the IDH1 allosteric pocket that differ from IDH2 may also guide IDH1 isoform selectivity. These data provide a deeper understanding of how IDH1 inhibitors achieve mutant and isoform selectivity.

  14. A broad phenotypic screen identifies novel phenotypes driven by a single mutant allele in Huntington's disease CAG knock-in mice.

    Directory of Open Access Journals (Sweden)

    Sabine M Hölter

    Full Text Available Huntington's disease (HD is an autosomal dominant neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat in the HTT gene encoding huntingtin. The disease has an insidious course, typically progressing over 10-15 years until death. Currently there is no effective disease-modifying therapy. To better understand the HD pathogenic process we have developed genetic HTT CAG knock-in mouse models that accurately recapitulate the HD mutation in man. Here, we describe results of a broad, standardized phenotypic screen in 10-46 week old heterozygous HdhQ111 knock-in mice, probing a wide range of physiological systems. The results of this screen revealed a number of behavioral abnormalities in HdhQ111/+ mice that include hypoactivity, decreased anxiety, motor learning and coordination deficits, and impaired olfactory discrimination. The screen also provided evidence supporting subtle cardiovascular, lung, and plasma metabolite alterations. Importantly, our results reveal that a single mutant HTT allele in the mouse is sufficient to elicit multiple phenotypic abnormalities, consistent with a dominant disease process in patients. These data provide a starting point for further investigation of several organ systems in HD, for the dissection of underlying pathogenic mechanisms and for the identification of reliable phenotypic endpoints for therapeutic testing.

  15. Dominant Drop mutants are gain-of-function alleles of the muscle segment homeobox gene (msh) whose overexpression leads to the arrest of eye development.

    Science.gov (United States)

    Mozer, B A

    2001-05-15

    Dominant Drop (Dr) mutations are nearly eyeless and have additional recessive phenotypes including lethality and patterning defects in eye and sensory bristles due to cis-regulatory lesions in the cell cycle regulator string (stg). Genetic analysis demonstrates that the dominant small eye phenotype is the result of separate gain-of-function mutations in the closely linked muscle segment homeobox (msh) gene, encoding a homeodomain transcription factor required for patterning of muscle and nervous system. Reversion of the Dr(Mio) allele was coincident with the generation of lethal loss-of-function mutations in msh in cis, suggesting that the dominant eye phenotype is the result of ectopic expression. Molecular genetic analysis revealed that two dominant Dr alleles contain lesions upstream of the msh transcription start site. In the Dr(Mio) mutant, a 3S18 retrotransposon insertion is the target of second-site mutations (P-element insertions or deletions) which suppress the dominant eye phenotype following reversion. The pattern of 3S18 expression and the absence of msh in eye imaginal discs suggest that transcriptional activation of the msh promoter accounts for ectopic expression. Dr dominant mutations arrest eye development by blocking the progression of the morphogenetic furrow leading to photoreceptor cell loss via apoptosis. Gal4-mediated ubiquitous expression of msh in third-instar larvae was sufficient to arrest the morphogenetic furrow in the eye imaginal disc and resulted in lethality prior to eclosion. Dominant mutations in the human msx2 gene, one of the vertebrate homologs of msh, are associated with craniosynostosis, a disease affecting cranial development. The Dr mutations are the first example of gain-of-function mutations in the msh/msx gene family identified in a genetically tractible model organism and may serve as a useful tool to identify additional genes that regulate this class of homeodomain proteins. Copyright 2001 Academic Press.

  16. Mutant alleles of FAD2-1A and FAD2-1B combine to produce soybeans with the high oleic acid seed oil trait

    Directory of Open Access Journals (Sweden)

    Pham Anh-Tung

    2010-09-01

    Full Text Available Abstract Background The alteration of fatty acid profiles in soybean [Glycine max (L. Merr.] to improve soybean oil quality is an important and evolving theme in soybean research to meet nutritional needs and industrial criteria in the modern market. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of the oil. Commodity soybean oil typically contains 20% oleic acid and the target for high oleic acid soybean oil is approximately 80% of the oil; previous conventional plant breeding research to raise the oleic acid level to just 50-60% of the oil was hindered by the genetic complexity and environmental instability of the trait. The objective of this work was to create the high oleic acid trait in soybeans by identifying and combining mutations in two delta-twelve fatty acid desaturase genes, FAD2-1A and FAD2-1B. Results Three polymorphisms found in the FAD2-1B alleles of two soybean lines resulted in missense mutations. For each of the two soybean lines, there was one unique amino acid change within a highly conserved region of the protein. The mutant FAD2-1B alleles were associated with an increase in oleic acid levels, although the FAD2-1B mutant alleles alone were not capable of producing a high oleic acid phenotype. When existing FAD2-1A mutations were combined with the novel mutant FAD2-1B alleles, a high oleic acid phenotype was recovered only for those lines which were homozygous for both of the mutant alleles. Conclusions We were able to produce conventional soybean lines with 80% oleic acid in the oil in two different ways, each requiring the contribution of only two genes. The high oleic acid soybean germplasm developed contained a desirable fatty acid profile, and it was stable in two production environments. The presumed causative sequence polymorphisms in the FAD2-1B alleles were developed into highly efficient molecular markers for tracking the

  17. Mutant alleles of FAD2-1A and FAD2-1B combine to produce soybeans with the high oleic acid seed oil trait.

    Science.gov (United States)

    Pham, Anh-Tung; Lee, Jeong-Dong; Shannon, J Grover; Bilyeu, Kristin D

    2010-09-09

    The alteration of fatty acid profiles in soybean [Glycine max (L.) Merr.] to improve soybean oil quality is an important and evolving theme in soybean research to meet nutritional needs and industrial criteria in the modern market. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of the oil. Commodity soybean oil typically contains 20% oleic acid and the target for high oleic acid soybean oil is approximately 80% of the oil; previous conventional plant breeding research to raise the oleic acid level to just 50-60% of the oil was hindered by the genetic complexity and environmental instability of the trait. The objective of this work was to create the high oleic acid trait in soybeans by identifying and combining mutations in two delta-twelve fatty acid desaturase genes, FAD2-1A and FAD2-1B. Three polymorphisms found in the FAD2-1B alleles of two soybean lines resulted in missense mutations. For each of the two soybean lines, there was one unique amino acid change within a highly conserved region of the protein. The mutant FAD2-1B alleles were associated with an increase in oleic acid levels, although the FAD2-1B mutant alleles alone were not capable of producing a high oleic acid phenotype. When existing FAD2-1A mutations were combined with the novel mutant FAD2-1B alleles, a high oleic acid phenotype was recovered only for those lines which were homozygous for both of the mutant alleles. We were able to produce conventional soybean lines with 80% oleic acid in the oil in two different ways, each requiring the contribution of only two genes. The high oleic acid soybean germplasm developed contained a desirable fatty acid profile, and it was stable in two production environments. The presumed causative sequence polymorphisms in the FAD2-1B alleles were developed into highly efficient molecular markers for tracking the mutant alleles. The resources described here for the creation

  18. Gene structure and mutant alleles of PCDH15: nonsyndromic deafness DFNB23 and type 1 Usher syndrome.

    Science.gov (United States)

    Ahmed, Zubair M; Riazuddin, Saima; Aye, Sandar; Ali, Rana A; Venselaar, Hanka; Anwar, Saima; Belyantseva, Polina P; Qasim, Muhammad; Riazuddin, Sheikh; Friedman, Thomas B

    2008-10-01

    Mutations of PCDH15, encoding protocadherin 15, can cause either combined hearing and vision impairment (type 1 Usher syndrome; USH1F) or nonsyndromic deafness (DFNB23). Human PCDH15 is reported to be composed of 35 exons and encodes a variety of isoforms with 3-11 ectodomains (ECs), a transmembrane domain and a carboxy-terminal cytoplasmic domain (CD). Building on these observations, we describe an updated gene structure that has four additional exons of PCDH15 and isoforms that can be subdivided into four classes. Human PCDH15 encodes three alternative, evolutionarily conserved unique cytoplasmic domains (CD1, CD2 or CD3). Families ascertained on the basis of prelingual hearing loss were screened for linkage of this phenotype to markers for PCDH15 on chromosome 10q21.1. In seven of twelve families segregating USH1, we identified homozygous mutant alleles (one missense, one splice site, three nonsense and two deletion mutations) of which six are novel. One family was segregating nonsyndromic deafness DFNB23 due to a homozygous missense mutation. To date, in our cohort of 557 Pakistani families, we have found 11 different PCDH15 mutations that account for deafness in 13 families. Molecular modeling provided mechanistic insight into the phenotypic variation in severity of the PCDH15 missense mutations. We did not find pathogenic mutations in five of the twelve USH1 families linked to markers for USH1F, which suggest either the presence of mutations of yet additional undiscovered exons of PCDH15, mutations in the introns or regulatory elements of PCDH15, or an additional locus for type I USH at chromosome 10q21.1.

  19. A genetic screen for vascular mutants in zebrafish reveals dynamic roles for Vegf/Plcg1 signaling during artery development.

    Science.gov (United States)

    Covassin, L D; Siekmann, A F; Kacergis, M C; Laver, E; Moore, J C; Villefranc, J A; Weinstein, B M; Lawson, N D

    2009-05-15

    In this work we describe a forward genetic approach to identify mutations that affect blood vessel development in the zebrafish. By applying a haploid screening strategy in a transgenic background that allows direct visualization of blood vessels, it was possible to identify several classes of mutant vascular phenotypes. Subsequent characterization of mutant lines revealed that defects in Vascular endothelial growth factor (Vegf) signaling specifically affected artery development. Comparison of phenotypes associated with different mutations within a functional zebrafish Vegf receptor-2 ortholog (referred to as kdr-like, kdrl) revealed surprisingly varied effects on vascular development. In parallel, we identified an allelic series of mutations in phospholipase c gamma 1 (plcg1). Together with in vivo structure-function analysis, our results suggest a requirement for Plcg1 catalytic activity downstream of receptor tyrosine kinases. We further find that embryos lacking both maternal and zygotic plcg1 display more severe defects in artery differentiation but are otherwise similar to zygotic mutants. Finally, we demonstrate through mosaic analysis that plcg1 functions autonomously in endothelial cells. Together our genetic analyses suggest that Vegf/Plcg1 signaling acts at multiple time points and in different signaling contexts to mediate distinct aspects of artery development.

  20. Cas9/sgRNA selective targeting of the P23H Rhodopsin mutant allele for treating retinitis pigmentosa by intravitreal AAV9.PHP.B-based delivery.

    Science.gov (United States)

    Giannelli, Serena G; Luoni, Mirko; Castoldi, Valerio; Massimino, Luca; Cabassi, Tommaso; Angeloni, Debora; Demontis, Gian Carlo; Leocani, Letizia; Andreazzoli, Massimiliano; Broccoli, Vania

    2018-03-01

    P23H is the most common mutation in the RHODOPSIN (RHO) gene leading to a dominant form of retinitis pigmentosa (RP), a rod photoreceptor degeneration that invariably causes vision loss. Specific disruption of the disease P23H RHO mutant while preserving the wild-type (WT) functional allele would be an invaluable therapy for this disease. However, various technologies tested in the past failed to achieve effective changes and consequently therapeutic benefits. We validated a CRISPR/Cas9 strategy to specifically inactivate the P23H RHO mutant, while preserving the WT allele in vitro. We, then, translated this approach in vivo by delivering the CRISPR/Cas9 components in murine Rho+/P23H mutant retinae. Targeted retinae presented a high rate of cleavage in the P23H but not WT Rho allele. This gene manipulation was sufficient to slow photoreceptor degeneration and improve retinal functions. To improve the translational potential of our approach, we tested intravitreal delivery of this system by means of adeno-associated viruses (AAVs). To this purpose, the employment of the AAV9-PHP.B resulted the most effective in disrupting the P23H Rho mutant. Finally, this approach was translated successfully in human cells engineered with the homozygous P23H RHO gene mutation. Overall, this is a significant proof-of-concept that gene allele specific targeting by CRISPR/Cas9 technology is specific and efficient and represents an unprecedented tool for treating RP and more broadly dominant genetic human disorders affecting the eye, as well as other tissues.

  1. Enhanced proteolysis of thiopurine S-methyltransferase (TPMT) encoded by mutant alleles in humans (TPMT∗3A, TPMT∗2): Mechanisms for the genetic polymorphism of TPMT activity

    OpenAIRE

    Tai, Hung-Liang; Krynetski, Eugene Y.; Schuetz, Erin G.; Yanishevski, Yuri; Evans, William E.

    1997-01-01

    TPMT is a cytosolic enzyme that catalyzes the S-methylation of aromatic and heterocyclic sulfhydryl compounds, including medications such as mercaptopurine and thioguanine. TPMT activity exhibits autosomal codominant genetic polymorphism, and patients inheriting TPMT deficiency are at high risk of potentially fatal hematopoietic toxicity. The most prevalent mutant alleles associated with TPMT deficiency in humans have been cloned and characterized (TPMT∗2 and TPMT∗3A), but the mechanisms for ...

  2. An efficient method for generation of bi-allelic null mutant mouse embryonic stem cells and its application for investigating epigenetic modifiers.

    Science.gov (United States)

    Fisher, Cynthia L; Marks, Hendrik; Cho, Lily Ting-Yin; Andrews, Robert; Wormald, Sam; Carroll, Thomas; Iyer, Vivek; Tate, Peri; Rosen, Barry; Stunnenberg, Hendrik G; Fisher, Amanda G; Skarnes, William C

    2017-12-01

    Mouse embryonic stem (ES) cells are a popular model system to study biological processes, though uncovering recessive phenotypes requires inactivating both alleles. Building upon resources from the International Knockout Mouse Consortium (IKMC), we developed a targeting vector for second allele inactivation in conditional-ready IKMC 'knockout-first' ES cell lines. We applied our technology to several epigenetic regulators, recovering bi-allelic targeted clones with a high efficiency of 60% and used Flp recombinase to restore expression in two null cell lines to demonstrate how our system confirms causality through mutant phenotype reversion. We designed our strategy to select against re-targeting the 'knockout-first' allele and identify essential genes in ES cells, including the histone methyltransferase Setdb1. For confirmation, we exploited the flexibility of our system, enabling tamoxifen inducible conditional gene ablation while controlling for genetic background and tamoxifen effects. Setdb1 ablated ES cells exhibit severe growth inhibition, which is not rescued by exogenous Nanog expression or culturing in naive pluripotency '2i' media, suggesting that the self-renewal defect is mediated through pluripotency network independent pathways. Our strategy to generate null mutant mouse ES cells is applicable to thousands of genes and repurposes existing IKMC Intermediate Vectors. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. The glossyhead1 allele of acc1 reveals a principal role for multidomain acetyl-coenzyme a carboxylase in the biosynthesis of cuticular waxes by Arabidopsis

    KAUST Repository

    Lu, Shiyou

    2011-09-23

    A novel mutant of Arabidopsis (Arabidopsis thaliana), having highly glossy inflorescence stems, postgenital fusion in floral organs, and reduced fertility, was isolated from an ethyl methanesulfonate-mutagenized population and designated glossyhead1 (gsd1). The gsd1 locus was mapped to chromosome 1, and the causal gene was identified as a new allele of Acetyl-Coenzyme A Carboxylase1 (ACC1), a gene encoding the main enzyme in cytosolic malonyl-coenzyme A synthesis. This, to our knowledge, is the first mutant allele of ACC1 that does not cause lethality at the seed or early germination stage, allowing for the first time a detailed analysis of ACC1 function in mature tissues. Broad lipid profiling of mature gsd1 organs revealed a primary role for ACC1 in the biosynthesis of the very-long-chain fatty acids (C 20:0 or longer) associated with cuticular waxes and triacylglycerols. Unexpectedly, transcriptome analysis revealed that gsd1 has limited impact on any lipid metabolic networks but instead has a large effect on environmental stress-responsive pathways, especially senescence and ethylene synthesis determinants, indicating a possible role for the cytosolic malonyl-coenzyme A-derived lipids in stress response signaling. © 2011 American Society of Plant Biologists. All Rights Reserved.

  4. Frequencies distribution of dihydrofolate reductase and dihydropteroate synthetase mutant alleles associated with sulfadoxine-pyrimethamine resistance in Plasmodium falciparum population from Hadhramout Governorate, Yemen.

    Science.gov (United States)

    Bamaga, Omar A A; Mahdy, Mohammed A K; Lim, Yvonne A L

    2015-12-22

    Malaria in Yemen is mainly caused by Plasmodium falciparum and 25% of the population is at high risk. Sulfadoxine-pyrimethamine (SP) had been used as monotherapy against P. falciparum. Emergence of chloroquine resistance led to the shift in anti-malarial treatment policy in Yemen to artemisinin-based combination therapy, that is artesunate (AS) plus SP as first-line therapy for uncomplicated malaria and artemether-lumefantrine as second-line treatment. This study aimed to screen mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes associated with SP resistance among P. falciparum population in Hadhramout governorate, Yemen. Genomic DNA was extracted from dried blood spots of 137 P. falciparum isolates collected from a community-based study. DNA was amplified using nested polymerase chain reaction (PCR) and subsequently sequenced for Pfdhfr and Pfdhps genes. Sequences were analysed for mutations in Pfdhfr gene codons 51, 59, 108, and 164 and in Pfdhps gene codons 436, 437, and 540. A total of 128 and 114 P. falciparum isolates were successfully sequenced for Pfdhfr and Pfdhps genes, respectively. Each Pfdhfr mutant allele (I51 and N108) in P. falciparum population had a frequency of 84%. Pfdhfr R59 mutant allele was detected in one isolate. Mutation at codon 437 (G437) in the Pfdhps gene was detected in 44.7% of falciparum malaria isolates. Frequencies of Pfdhfr double mutant genotype (I51C59N108I164) and Pfdhfr/Pfdhps triple mutant genotype (I51C59N108I164-S436G437K540) were 82.8 and 39.3%, respectively. One isolate harboured Pfdhfr triple mutant genotype (I51, R59, N108, I164) and Pfdhfr/Pfdhps quadruple mutant genotype (I51R59N108I164-S436G437K540). High frequencies of Pfdhfr and Pfdhps mutant alleles and genotypes in P. falciparum population in Hadhramout, Yemen, highlight the risk of developing resistance for SP, the partner drug of AS, which subsequently will expose the parasite to AS monotherapy increasing then the

  5. Rapid genotyping assays for the 4-base pair deletion of canine MDR1/ABCB1 gene and low frequency of the mutant allele in Border Collie dogs.

    Science.gov (United States)

    Mizukami, Keijiro; Chang, Hye-Sook; Yabuki, Akira; Kawamichi, Takuji; Hossain, Mohammad A; Rahman, Mohammad M; Uddin, Mohammad M; Yamato, Osamu

    2012-01-01

    P-glycoprotein, encoded by the MDR1 or ABCB1 gene, is an integral component of the blood-brain barrier as an efflux pump for xenobiotics crucial in limiting drug uptake into the central nervous system. Dogs homozygous for a 4-base pair deletion of the canine MDR1 gene show altered expression or function of P-glycoprotein, resulting in neurotoxicosis after administration of the substrate drugs. In the present study, the usefulness of microchip electrophoresis for genotyping assays detecting this deletion mutation was evaluated. Mutagenically separated polymerase chain reaction (MS-PCR) and real-time PCR assays were newly developed and evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies dogs in Japan to determine the allele frequency in this breed. Microchip electrophoresis showed advantages in detection sensitivity and time saving over other modes of electrophoresis. The MS-PCR assay clearly discriminated all genotypes. Real-time PCR assay was most suitable for a large-scale survey due to its high throughput and rapidity. The genotyping survey demonstrated that the carrier and mutant allele frequencies were 0.49% and 0.25%, respectively, suggesting that the mutant allele frequency in Border Collies is markedly low compared to that in the susceptible dog breeds such as rough and smooth Collies.

  6. Phosphorus Partitioning of Soybean Lines Containing Different Mutant Alleles of Two Soybean Seed-Specific Adenosine Triphosphate-Binding Cassette Phytic Acid Transporter Paralogs

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    Jason D. Gillman

    2013-03-01

    Full Text Available Seed phytate is a repository of P and minerals in soybean [ (L. Merr.] seeds that limits P and mineral bioavailability for monogastric animals (e.g., humans, swine [], and poultry [especially chicken, ] due to insufficient digestive tract phytase activity. We previously identified epistatic recessive mutations affecting two paralogous adenosine triphosphate-binding cassette phytic acid transporter genes (one a nonsense mutation in and the other a missense mutation in as the molecular genetic basis in the ethyl methanesulfonate (EMS-induced mutant low phytate soybean line M153. An additional mutant low phytate line, M766, contained one single nucleotide polymorphism within the ninth intron of the locus as well as a nonsense mutation in . The objectives of this research were to clarify the genetics underlying the low phytate phenotype in line M766 and to determine P partitioning in new combinations of mutant alleles from M766 and M153. Inheritance of nonsense alleles affecting both ( genes (one from M153 and one from M766 led to the production of viable seeds that contained transgressive reductions in total seed phytate and significantly higher levels of inorganic phosphate than has been reported for nontransgenic soybean material and will allow efficient molecular selection of soybeans with even greater reductions of phytate for improved quality soybean meal.

  7. Concurrent MPL515 and JAK2V617F mutations in myelofibrosis: chronology of clonal emergence and changes in mutant allele burden over time.

    Science.gov (United States)

    Lasho, Terra L; Pardanani, Animesh; McClure, Rebecca F; Mesa, Ruben A; Levine, Ross L; Gilliland, D Gary; Tefferi, Ayalew

    2006-12-01

    MPLW515L/K and JAK2V617F can co-exist in myelofibrosis with myeloid metaplasia (MMM). The chronology of clonal emergence was studied in three such cases using serially stored bone marrow. At diagnosis, a major MPL515 mutant clone was accompanied by a minor JAK2V617F clone in all three instances. At 25 time points over a period of 4-8 years, allele burden fluctuated but remained high for MPLW515L/K and low for JAK2V617F. We conclude that MPLW515L/K and JAK2V617F are both early events in MMM and allele burden, rather than the mere presence of these mutations, might be relevant to phenotypic variation in myeloproliferative disorders.

  8. Ultraviolet-induced reversion of cyc1 alleles in radiation-sensitive strains of yeast. III. rev 3 mutant strains

    International Nuclear Information System (INIS)

    Lawrence, C.W.; Crhistensen, R.B.

    1979-01-01

    The role of rev3 gene function in uv-induced mutagenesis in the yeast Saccharomyces cerevisiae has been examined by determining the reversion of 12 well-defined cyc1 mutations in diploid strains homozygous for the rev3-1 or rev3-3 allale. The 12 cyc1 alleles include one ochre, one amber, four initiation, two proline missense, and four frameshift mutations. We find that the rev3 mutations reduce the frequency of UV-induced reversion of all of the cyc1 alleles, though different classes of alleles respond to a different extent. These results imply that the rev3 gene function is required for the production of a wide variety of mutational events, though probably not all, and show that each of the three rev loci have different mutational phenotypes. Such diverse phenotypes are not predicted by the unitary model for bacterial mutagenes, suggesting that this is at best an incomplete description of eukaryotic mutagenesis

  9. Genetic dissection of the Drosophila melanogaster female head transcriptome reveals widespread allelic heterogeneity.

    Science.gov (United States)

    King, Elizabeth G; Sanderson, Brian J; McNeil, Casey L; Long, Anthony D; Macdonald, Stuart J

    2014-05-01

    Modern genetic mapping is plagued by the "missing heritability" problem, which refers to the discordance between the estimated heritabilities of quantitative traits and the variance accounted for by mapped causative variants. One major potential explanation for the missing heritability is allelic heterogeneity, in which there are multiple causative variants at each causative gene with only a fraction having been identified. The majority of genome-wide association studies (GWAS) implicitly assume that a single SNP can explain all the variance for a causative locus. However, if allelic heterogeneity is prevalent, a substantial amount of genetic variance will remain unexplained. In this paper, we take a haplotype-based mapping approach and quantify the number of alleles segregating at each locus using a large set of 7922 eQTL contributing to regulatory variation in the Drosophila melanogaster female head. Not only does this study provide a comprehensive eQTL map for a major community genetic resource, the Drosophila Synthetic Population Resource, but it also provides a direct test of the allelic heterogeneity hypothesis. We find that 95% of cis-eQTLs and 78% of trans-eQTLs are due to multiple alleles, demonstrating that allelic heterogeneity is widespread in Drosophila eQTL. Allelic heterogeneity likely contributes significantly to the missing heritability problem common in GWAS studies.

  10. Genetic dissection of the Drosophila melanogaster female head transcriptome reveals widespread allelic heterogeneity.

    Directory of Open Access Journals (Sweden)

    Elizabeth G King

    2014-05-01

    Full Text Available Modern genetic mapping is plagued by the "missing heritability" problem, which refers to the discordance between the estimated heritabilities of quantitative traits and the variance accounted for by mapped causative variants. One major potential explanation for the missing heritability is allelic heterogeneity, in which there are multiple causative variants at each causative gene with only a fraction having been identified. The majority of genome-wide association studies (GWAS implicitly assume that a single SNP can explain all the variance for a causative locus. However, if allelic heterogeneity is prevalent, a substantial amount of genetic variance will remain unexplained. In this paper, we take a haplotype-based mapping approach and quantify the number of alleles segregating at each locus using a large set of 7922 eQTL contributing to regulatory variation in the Drosophila melanogaster female head. Not only does this study provide a comprehensive eQTL map for a major community genetic resource, the Drosophila Synthetic Population Resource, but it also provides a direct test of the allelic heterogeneity hypothesis. We find that 95% of cis-eQTLs and 78% of trans-eQTLs are due to multiple alleles, demonstrating that allelic heterogeneity is widespread in Drosophila eQTL. Allelic heterogeneity likely contributes significantly to the missing heritability problem common in GWAS studies.

  11. Two mutant alleles of the human cytochrome P-450dbl gene (P450C2D1) associated with genetically deficient metabolism of debrisoquine and other drugs

    International Nuclear Information System (INIS)

    Skoda, R.C.; Gonzalez, F.L.; Demierre, A.; Meyer, R.A.

    1988-01-01

    The debrisoquine polymorphism is a clinically important genetic defect of drug metabolism affecting 5-10% of individuals in Caucasian populations. It is inherited as an autosomal recessive trait. A full-length cDNA for human cytochrome P-450db1, the deficient enzyme (also designated P450IID1 for P450 family II subfamily D isozyme 1), has recently been cloned. Leukocyte DNA from extensive metabolizers (EMs) or poor metabolizers (PMs) of debrisoquine was examined by Southern analysis. Two polymorphic restriction fragments were associated with the PM phenotype when DNAs from 24 unrelated PM and 29 unrelated EM individuals were probed with P-450db1 cDNA after digestion with Xba I restriction endonuclease and Southern blotting. Seventy-five percent of PMs had either the 44-kb or the 11.5-kb fragment or both. Segregation of these restriction fragment length polymorphisms in the families of six PM probands demonstrated that each of the two fragments is allelic with the 29-kb fragment present in all EM individuals and suggests that they identify two independent mutated alleles of the P-450db1 gene (designated P450C2D1). The Xba I 44-kb fragment and 11.5-kb fragment were in linkage disequilibrium with restriction fragment length polymorphisms generated by four and five additional restriction endonucleases, respectively, which can be used to identify the same mutant alleles for the P-450db1 gene

  12. Structural Analysis of Insulin Minisatellite Alleles Reveals Unusually Large Differences in Diversity between Africans and Non-Africans

    Science.gov (United States)

    Stead, John D. H.; Jeffreys, Alec J.

    2002-01-01

    The insulin minisatellite (INS VNTR) associates with susceptibility to a variety of diseases. We have developed a high-resolution system for analyzing variant repeat distributions applicable to all known minisatellite alleles, irrespective of size, which allows lineages of related alleles to be identified. This system has previously revealed extremely low structural diversity in the minisatellite among northern Europeans from the United Kingdom, with all alleles belonging to one of only three highly diverged lineages called “I,” “IIIA,” and “IIIB.” To explore the origins of this remarkably limited lineage diversity, we have characterized an additional 780 alleles from three non-African and three African populations. In total, 22 highly diverged lineages were identified, with structural intermediates absent from extant populations, suggesting a bottleneck within the ancestry of all humans. The difference between levels of diversity in Africans and non-Africans is unusually large, with all 22 lineages identified in Africa compared with only three lineages seen not only in the United Kingdom but also in the other non-African populations. We also find evidence for overrepresentation of lineage I chromosomes in non-Africans. These data are consistent with a common out-of-Africa origin and an unusually tight bottleneck within the ancestry of all non-African populations, possibly combined with differential and positive selection for lineage I alleles in non-Africans. The important implications of these data for future disease-association studies are discussed. PMID:12404181

  13. Abnormal trafficking of endogenously expressed BMPR2 mutant allelic products in patients with heritable pulmonary arterial hypertension.

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    Andrea L Frump

    Full Text Available More than 200 heterozygous mutations in the type 2 BMP receptor gene, BMPR2, have been identified in patients with Heritable Pulmonary Arterial Hypertension (HPAH. More severe clinical outcomes occur in patients with BMPR2 mutations by-passing nonsense-mediated mRNA decay (NMD negative mutations. These comprise 40% of HPAH mutations and are predicted to express BMPR2 mutant products. However expression of endogenous NMD negative BMPR2 mutant products and their effect on protein trafficking and signaling function have never been described. Here, we characterize the expression and trafficking of an HPAH-associated NMD negative BMPR2 mutation that results in an in-frame deletion of BMPR2 EXON2 (BMPR2ΔEx2 in HPAH patient-derived lymphocytes and in pulmonary endothelial cells (PECs from mice carrying the same in-frame deletion of Exon 2 (Bmpr2 (ΔEx2/+ mice. The endogenous BMPR2ΔEx2 mutant product does not reach the cell surface and is retained in the endoplasmic reticulum. Moreover, chemical chaperones 4-PBA and TUDCA partially restore cell surface expression of Bmpr2ΔEx2 in PECs, suggesting that the mutant product is mis-folded. We also show that PECs from Bmpr2 (ΔEx2/+ mice have defects in the BMP-induced Smad1/5/8 and Id1 signaling axis, and that addition of chemical chaperones restores expression of the Smad1/5/8 target Id1. These data indicate that the endogenous NMD negative BMPRΔEx2 mutant product is expressed but has a folding defect resulting in ER retention. Partial correction of this folding defect and restoration of defective BMP signaling using chemical chaperones suggests that protein-folding agents could be used therapeutically in patients with these NMD negative BMPR2 mutations.

  14. Clinical relevance of IDH1/2 mutant allele burden during follow-up in acute myeloid leukemia. A study by the French ALFA group

    Science.gov (United States)

    Ferret, Yann; Boissel, Nicolas; Helevaut, Nathalie; Madic, Jordan; Nibourel, Olivier; Marceau-Renaut, Alice; Bucci, Maxime; Geffroy, Sandrine; Celli-Lebras, Karine; Castaigne, Sylvie; Thomas, Xavier; Terré, Christine; Dombret, Hervé; Preudhomme, Claude; Renneville, Aline

    2018-01-01

    Assessment of minimal residual disease has emerged as a powerful prognostic factor in acute myeloid leukemia. In this study, we investigated the potential of IDH1/2 mutations as targets for minimal residual disease assessment in acute myeloid leukemia, since these mutations collectively occur in 15–20% of cases of acute myeloid leukemia and now represent druggable targets. We employed droplet digital polymerase chain reaction assays to quantify IDH1R132, IDH2R140, and IDH2R172 mutations on genomic DNA in 322 samples from 103 adult patients with primary IDH1/2 mutant acute myeloid leukemia and enrolled on Acute Leukemia French Association (ALFA) - 0701 or -0702 clinical trials. The median IDH1/2 mutant allele fraction in bone marrow samples was 42.3% (range, 8.2 – 49.9%) at diagnosis of acute myeloid leukemia, and below the detection limit of 0.2% (range, <0.2 – 39.3%) in complete remission after induction therapy. In univariate analysis, the presence of a normal karyotype, a NPM1 mutation, and an IDH1/2 mutant allele fraction <0.2% in bone marrow after induction therapy were statistically significant predictors of longer disease-free survival. In multivariate analysis, these three variables remained significantly predictive of disease-free survival. In 7/103 (7%) patients, IDH1/2 mutations persisted at high levels in complete remission, consistent with the presence of an IDH1/2 mutation in pre-leukemic hematopoietic stem cells. Five out of these seven patients subsequently relapsed or progressed toward myelodysplastic syndrome, suggesting that patients carrying the IDH1/2 mutation in a pre-leukemic clone may be at high risk of hematologic evolution. PMID:29472349

  15. Tumor transcriptome sequencing reveals allelic expression imbalances associated with copy number alterations.

    Directory of Open Access Journals (Sweden)

    Brian B Tuch

    Full Text Available Due to growing throughput and shrinking cost, massively parallel sequencing is rapidly becoming an attractive alternative to microarrays for the genome-wide study of gene expression and copy number alterations in primary tumors. The sequencing of transcripts (RNA-Seq should offer several advantages over microarray-based methods, including the ability to detect somatic mutations and accurately measure allele-specific expression. To investigate these advantages we have applied a novel, strand-specific RNA-Seq method to tumors and matched normal tissue from three patients with oral squamous cell carcinomas. Additionally, to better understand the genomic determinants of the gene expression changes observed, we have sequenced the tumor and normal genomes of one of these patients. We demonstrate here that our RNA-Seq method accurately measures allelic imbalance and that measurement on the genome-wide scale yields novel insights into cancer etiology. As expected, the set of genes differentially expressed in the tumors is enriched for cell adhesion and differentiation functions, but, unexpectedly, the set of allelically imbalanced genes is also enriched for these same cancer-related functions. By comparing the transcriptomic perturbations observed in one patient to his underlying normal and tumor genomes, we find that allelic imbalance in the tumor is associated with copy number mutations and that copy number mutations are, in turn, strongly associated with changes in transcript abundance. These results support a model in which allele-specific deletions and duplications drive allele-specific changes in gene expression in the developing tumor.

  16. Functional importance of conserved domains in the flowering-time gene CONSTANS demonstrated by analysis of mutant alleles and transgenic plants.

    Science.gov (United States)

    Robson, F; Costa, M M; Hepworth, S R; Vizir, I; Piñeiro, M; Reeves, P H; Putterill, J; Coupland, G

    2001-12-01

    CONSTANS promotes flowering of Arabidopsis in response to long-day conditions. We show that CONSTANS is a member of an Arabidopsis gene family that comprises 16 other members. The CO-Like proteins encoded by these genes contain two segments of homology: a zinc finger containing region near their amino terminus and a CCT (CO, CO-Like, TOC1) domain near their carboxy terminus. Analysis of seven classical co mutant alleles demonstrated that the mutations all occur within either the zinc finger region or the CCT domain, confirming that the two regions of homology are important for CO function. The zinc fingers are most similar to those of B-boxes, which act as protein-protein interaction domains in several transcription factors described in animals. Segments of CO protein containing the CCT domain localize GFP to the nucleus, but one mutation that affects the CCT domain delays flowering without affecting the nuclear localization function, suggesting that this domain has additional functions. All eight co alleles, including one recovered by pollen irradiation in which DNA encoding both B-boxes is deleted, are shown to be semidominant. This dominance appears to be largely due to a reduction in CO dosage in the heterozygous plants. However, some alleles may also actively delay flowering, because overexpression from the CaMV 35S promoter of the co-3 allele, that has a mutation in the second B-box, delayed flowering of wild-type plants. The significance of these observations for the role of CO in the control of flowering time is discussed.

  17. A Landscape of Therapeutic Cooperativity in KRAS Mutant Cancers Reveals Principles for Controlling Tumor Evolution

    Directory of Open Access Journals (Sweden)

    Grace R. Anderson

    2017-07-01

    Full Text Available Combinatorial inhibition of effector and feedback pathways is a promising treatment strategy for KRAS mutant cancers. However, the particular pathways that should be targeted to optimize therapeutic responses are unclear. Using CRISPR/Cas9, we systematically mapped the pathways whose inhibition cooperates with drugs targeting the KRAS effectors MEK, ERK, and PI3K. By performing 70 screens in models of KRAS mutant colorectal, lung, ovarian, and pancreas cancers, we uncovered universal and tissue-specific sensitizing combinations involving inhibitors of cell cycle, metabolism, growth signaling, chromatin regulation, and transcription. Furthermore, these screens revealed secondary genetic modifiers of sensitivity, yielding a SRC inhibitor-based combination therapy for KRAS/PIK3CA double-mutant colorectal cancers (CRCs with clinical potential. Surprisingly, acquired resistance to combinations of growth signaling pathway inhibitors develops rapidly following treatment, but by targeting signaling feedback or apoptotic priming, it is possible to construct three-drug combinations that greatly delay its emergence.

  18. Characterization of the Pseudomonas aeruginosa recA analog and its protein product: rec-102 is a mutant allele of the P. aeruginosa PAO recA gene

    International Nuclear Information System (INIS)

    Kokjohn, T.A.; Miller, R.V.

    1987-01-01

    We cloned a 2.3-kilobase-pair fragment of the Pseudomonas aeruginosa PAO chromosome which is capable of complementing recA mutations of Escherichia coli. The recA-complementing activity was further localized to a 1.5-kilobase-pair PvuII-HindIII fragment. Southern blot analysis under conditions of high stringency indicated that DNA sequence homology is shared by the E. coli recA gene and the P. aeruginosa recA analog. The cloned recA analog was shown to restore resistance to methyl methanesulfonate, nitrofurantoin, and UV irradiation to E. coli recA mutants. Upon introduction of the cloned P. aeruginosa gene, these mutants regained recombination proficiency in HfrH-mediated conjugation and the ability to induce lambda prophages and SOS functions (din gene transcription) after exposure to DNA-damaging agents. Lambda prophage carrying a cI ind mutation was not inducible, suggesting that the mechanism of induction of these SOS functions by the P. aeruginosa RecA analog is similar to that by the activated E. coli RecA protein. The product of the recA analog was identified in minicells as a protein of approximately 47,000 daltons. Western blot analysis using anti-E. coli RecA antibody demonstrated that this protein is antigenically cross-reactive with the E. coli recA protein. The recA-containing fragment was cloned into the broad-host-range vector pCP13 and introduced into Rec- strains of P. aeruginosa containing the rec-102 allele. The plasmid was shown to restore recombination proficiency in FP5-mediated conjugations and to restore resistance to UV irradiation and methyl methanesulfonate to these Rec- mutants. It was shown that a wild-type allele of rec-102 is necessary for UV-mediated induction of D3 and F116 prophages. The cloned recA analog restored the UV inducibility of these prophages in rec-102 mutants

  19. Characterization of the Pseudomonas aeruginosa recA analog and its protein product: rec-102 is a mutant allele of the P. aeruginosa PAO recA gene

    Energy Technology Data Exchange (ETDEWEB)

    Kokjohn, T.A.; Miller, R.V.

    1987-04-01

    We cloned a 2.3-kilobase-pair fragment of the Pseudomonas aeruginosa PAO chromosome which is capable of complementing recA mutations of Escherichia coli. The recA-complementing activity was further localized to a 1.5-kilobase-pair PvuII-HindIII fragment. Southern blot analysis under conditions of high stringency indicated that DNA sequence homology is shared by the E. coli recA gene and the P. aeruginosa recA analog. The cloned recA analog was shown to restore resistance to methyl methanesulfonate, nitrofurantoin, and UV irradiation to E. coli recA mutants. Upon introduction of the cloned P. aeruginosa gene, these mutants regained recombination proficiency in HfrH-mediated conjugation and the ability to induce lambda prophages and SOS functions (din gene transcription) after exposure to DNA-damaging agents. Lambda prophage carrying a cI ind mutation was not inducible, suggesting that the mechanism of induction of these SOS functions by the P. aeruginosa RecA analog is similar to that by the activated E. coli RecA protein. The product of the recA analog was identified in minicells as a protein of approximately 47,000 daltons. Western blot analysis using anti-E. coli RecA antibody demonstrated that this protein is antigenically cross-reactive with the E. coli recA protein. The recA-containing fragment was cloned into the broad-host-range vector pCP13 and introduced into Rec- strains of P. aeruginosa containing the rec-102 allele. The plasmid was shown to restore recombination proficiency in FP5-mediated conjugations and to restore resistance to UV irradiation and methyl methanesulfonate to these Rec- mutants. It was shown that a wild-type allele of rec-102 is necessary for UV-mediated induction of D3 and F116 prophages. The cloned recA analog restored the UV inducibility of these prophages in rec-102 mutants.

  20. Enhanced specificity of TPMT*2 genotyping using unidirectional wild-type and mutant allele-specific scorpion primers in a single tube.

    Directory of Open Access Journals (Sweden)

    Dong Chen

    Full Text Available Genotyping of thiopurine S-methyltransferase (TPMT is recommended for predicting the adverse drug response of thiopurines. In the current study, a novel version of allele-specific PCR (AS-PCR, termed competitive real-time fluorescent AS-PCR (CRAS-PCR was developed to analyze the TPMT*2 genotype in ethnic Chinese. This technique simultaneously uses wild-type and mutant allele-specific scorpion primers in a single reaction. To determine the optimal conditions for both traditional AS-PCR and CRAS-PCR, we used the Taguchi method, an engineering optimization process that balances the concentrations of all components using an orthogonal array rather than a factorial array. Instead of running up to 264 experiments with the conventional factorial method, the Taguchi method achieved the same optimization using only 16 experiments. The optimized CRAS-PCR system completely avoided non-specific amplification occurring in traditional AS-PCR and could be performed at much more relaxed reaction conditions at 1% sensitivity, similar to traditional AS-PCR. TPMT*2 genotyping of 240 clinical samples was consistent with published data. In conclusion, CRAS-PCR is a novel and robust genotyping method, and the Taguchi method is an effective tool for the optimization of molecular analysis techniques.

  1. Infidelity of SARS-CoV Nsp14-exonuclease mutant virus replication is revealed by complete genome sequencing.

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    Lance D Eckerle

    2010-05-01

    Full Text Available Most RNA viruses lack the mechanisms to recognize and correct mutations that arise during genome replication, resulting in quasispecies diversity that is required for pathogenesis and adaptation. However, it is not known how viruses encoding large viral RNA genomes such as the Coronaviridae (26 to 32 kb balance the requirements for genome stability and quasispecies diversity. Further, the limits of replication infidelity during replication of large RNA genomes and how decreased fidelity impacts virus fitness over time are not known. Our previous work demonstrated that genetic inactivation of the coronavirus exoribonuclease (ExoN in nonstructural protein 14 (nsp14 of murine hepatitis virus results in a 15-fold decrease in replication fidelity. However, it is not known whether nsp14-ExoN is required for replication fidelity of all coronaviruses, nor the impact of decreased fidelity on genome diversity and fitness during replication and passage. We report here the engineering and recovery of nsp14-ExoN mutant viruses of severe acute respiratory syndrome coronavirus (SARS-CoV that have stable growth defects and demonstrate a 21-fold increase in mutation frequency during replication in culture. Analysis of complete genome sequences from SARS-ExoN mutant viral clones revealed unique mutation sets in every genome examined from the same round of replication and a total of 100 unique mutations across the genome. Using novel bioinformatic tools and deep sequencing across the full-length genome following 10 population passages in vitro, we demonstrate retention of ExoN mutations and continued increased diversity and mutational load compared to wild-type SARS-CoV. The results define a novel genetic and bioinformatics model for introduction and identification of multi-allelic mutations in replication competent viruses that will be powerful tools for testing the effects of decreased fidelity and increased quasispecies diversity on viral replication

  2. Utilization of a ts-sacB selection system for the generation of a Mycobacterium avium serovar-8 specific glycopeptidolipid allelic exchange mutant

    Science.gov (United States)

    Irani, Vida R; Lee, Sun-Hwa; Eckstein, Torsten M; Inamine, Julia M; Belisle, John T; Maslow, Joel N

    2004-01-01

    Background Mycobacterium avium are ubiquitous environmental organisms and a cause of disseminated infection in patients with end-stage AIDS. The glycopeptidolipids (GPL) of M. avium are proposed to participate in the pathogenesis of this organism, however, establishment of a clear role for GPL in disease production has been limited by the inability to genetically manipulate M. avium. Methods To be able to study the role of the GPL in M. avium pathogenesis, a ts-sacB selection system, not previously used in M. avium, was employed as a means to achieve homologous recombination for the rhamnosyltransferase (rtfA) gene of a pathogenic serovar 8 strain of M. avium to prevent addition of serovar-specific sugars to rhamnose of the fatty acyl-peptide backbone of GPL. The genotype of the resultant rtfA mutant was confirmed by polymerase chain reaction and southern hybridization. Disruption in the proximal sugar of the haptenic oligosaccharide resulted in the loss of serovar specific GPL with no change in the pattern of non-serovar specific GPL moieties as shown by thin layer chromatography and gas chromatography/mass spectrometry. Complementation of wild type (wt) rtfA in trans through an integrative plasmid restored serovar-8 specific GPL expression identical to wt serovar 8 parent strain. Results In this study, we affirm our results that rtfA encodes an enzyme responsible for the transfer of Rha to 6d-Tal and provide evidence of a second allelic exchange mutagenesis system suitable for M. avium. Conclusion We report the second allelic exchange system for M. avium utilizing ts-sacB as double-negative and xylE as positive counter-selection markers, respectively. This system of allelic exchange would be especially useful for M. avium strains that demonstrate significant isoniazid (INH) resistance despite transformation with katG. Through the construction of mutants in GPL or other mycobacterial components, their roles in M. avium pathogenesis, biosynthesis, or drug

  3. Utilization of a ts-sacB selection system for the generation of a Mycobacterium avium serovar-8 specific glycopeptidolipid allelic exchange mutant

    Directory of Open Access Journals (Sweden)

    Belisle John T

    2004-09-01

    Full Text Available Abstract Background Mycobacterium avium are ubiquitous environmental organisms and a cause of disseminated infection in patients with end-stage AIDS. The glycopeptidolipids (GPL of M. avium are proposed to participate in the pathogenesis of this organism, however, establishment of a clear role for GPL in disease production has been limited by the inability to genetically manipulate M. avium. Methods To be able to study the role of the GPL in M. avium pathogenesis, a ts-sacB selection system, not previously used in M. avium, was employed as a means to achieve homologous recombination for the rhamnosyltransferase (rtfA gene of a pathogenic serovar 8 strain of M. avium to prevent addition of serovar-specific sugars to rhamnose of the fatty acyl-peptide backbone of GPL. The genotype of the resultant rtfA mutant was confirmed by polymerase chain reaction and southern hybridization. Disruption in the proximal sugar of the haptenic oligosaccharide resulted in the loss of serovar specific GPL with no change in the pattern of non-serovar specific GPL moieties as shown by thin layer chromatography and gas chromatography/mass spectrometry. Complementation of wild type (wt rtfA in trans through an integrative plasmid restored serovar-8 specific GPL expression identical to wt serovar 8 parent strain. Results In this study, we affirm our results that rtfA encodes an enzyme responsible for the transfer of Rha to 6d-Tal and provide evidence of a second allelic exchange mutagenesis system suitable for M. avium. Conclusion We report the second allelic exchange system for M. avium utilizing ts-sacB as double-negative and xylE as positive counter-selection markers, respectively. This system of allelic exchange would be especially useful for M. avium strains that demonstrate significant isoniazid (INH resistance despite transformation with katG. Through the construction of mutants in GPL or other mycobacterial components, their roles in M. avium pathogenesis

  4. The effect of altered dosage of a mutant allele of Teosinte branched 1 (tb1-ref) on the root system of modern maize.

    Science.gov (United States)

    Gaudin, Amelie C M; McClymont, Sarah A; Soliman, Sameh S M; Raizada, Manish N

    2014-02-14

    There was ancient human selection on the wild progenitor of modern maize, Balsas teosinte, for decreased shoot branching (tillering), in order to allow more nutrients to be diverted to grain. Mechanistically, the decline in shoot tillering has been associated with selection for increased expression of the major domestication gene Teosinte Branched 1 (Tb1) in shoot primordia. Therefore, TB1 has been defined as a repressor of shoot branching. It is known that plants respond to changes in shoot size by compensatory changes in root growth and architecture. However, it has not been reported whether altered TB1 expression affects any plant traits below ground. Previously, changes in dosage of a well-studied mutant allele of Tb1 in modern maize, called tb1-ref, from one to two copies, was shown to increase tillering. As a result, plants with two copies of the tb1-ref allele have a larger shoot biomass than heterozygotes. Here we used aeroponics to phenotype the effects of tb1-ref copy number on maize roots at macro-, meso- and micro scales of development. An increase in the tb1-ref copy number from one to two copies resulted in: (1) an increase in crown root number due to the cumulative initiation of crown roots from successive tillers; (2) higher density of first and second order lateral roots; and (3) reduced average lateral root length. The resulting increase in root system biomass in homozygous tb1-ref mutants balanced the increase in shoot biomass caused by enhanced tillering. These changes caused homozygous tb1-ref mutants of modern maize to more closely resemble its ancestor Balsas teosinte below ground. We conclude that a decrease in TB1 function in maize results in a larger root system, due to an increase in the number of crown roots and lateral roots. Given that decreased TB1 expression results in a more highly branched and larger shoot, the impact of TB1 below ground may be direct or indirect. We discuss the potential implications of these findings for whole

  5. Zebrafish eda and edar mutants reveal conserved and ancestral roles of ectodysplasin signaling in vertebrates.

    Directory of Open Access Journals (Sweden)

    Matthew P Harris

    2008-10-01

    Full Text Available The genetic basis of the development and variation of adult form of vertebrates is not well understood. To address this problem, we performed a mutant screen to identify genes essential for the formation of adult skeletal structures of the zebrafish. Here, we describe the phenotypic and molecular characterization of a set of mutants showing loss of adult structures of the dermal skeleton, such as the rays of the fins and the scales, as well as the pharyngeal teeth. The mutations represent adult-viable, loss of function alleles in the ectodysplasin (eda and ectodysplasin receptor (edar genes. These genes are frequently mutated in the human hereditary disease hypohidrotic ectodermal dysplasia (HED; OMIM 224900, 305100 that affects the development of integumentary appendages such as hair and teeth. We find mutations in zebrafish edar that affect similar residues as mutated in human cases of HED and show similar phenotypic consequences. eda and edar are not required for early zebrafish development, but are rather specific for the development of adult skeletal and dental structures. We find that the defects of the fins and scales are due to the role of Eda signaling in organizing epidermal cells into discrete signaling centers of the scale epidermal placode and fin fold. Our genetic analysis demonstrates dose-sensitive and organ-specific response to alteration in levels of Eda signaling. In addition, we show substantial buffering of the effect of loss of edar function in different genetic backgrounds, suggesting canalization of this developmental system. We uncover a previously unknown role of Eda signaling in teleosts and show conservation of the developmental mechanisms involved in the formation and variation of both integumentary appendages and limbs. Lastly, our findings point to the utility of adult genetic screens in the zebrafish in identifying essential developmental processes involved in human disease and in morphological evolution.

  6. Zebrafish eda and edar Mutants Reveal Conserved and Ancestral Roles of Ectodysplasin Signaling in Vertebrates

    Science.gov (United States)

    Harris, Matthew P.; Rohner, Nicolas; Schwarz, Heinz; Perathoner, Simon; Konstantinidis, Peter; Nüsslein-Volhard, Christiane

    2008-01-01

    The genetic basis of the development and variation of adult form of vertebrates is not well understood. To address this problem, we performed a mutant screen to identify genes essential for the formation of adult skeletal structures of the zebrafish. Here, we describe the phenotypic and molecular characterization of a set of mutants showing loss of adult structures of the dermal skeleton, such as the rays of the fins and the scales, as well as the pharyngeal teeth. The mutations represent adult-viable, loss of function alleles in the ectodysplasin (eda) and ectodysplasin receptor (edar) genes. These genes are frequently mutated in the human hereditary disease hypohidrotic ectodermal dysplasia (HED; OMIM 224900, 305100) that affects the development of integumentary appendages such as hair and teeth. We find mutations in zebrafish edar that affect similar residues as mutated in human cases of HED and show similar phenotypic consequences. eda and edar are not required for early zebrafish development, but are rather specific for the development of adult skeletal and dental structures. We find that the defects of the fins and scales are due to the role of Eda signaling in organizing epidermal cells into discrete signaling centers of the scale epidermal placode and fin fold. Our genetic analysis demonstrates dose-sensitive and organ-specific response to alteration in levels of Eda signaling. In addition, we show substantial buffering of the effect of loss of edar function in different genetic backgrounds, suggesting canalization of this developmental system. We uncover a previously unknown role of Eda signaling in teleosts and show conservation of the developmental mechanisms involved in the formation and variation of both integumentary appendages and limbs. Lastly, our findings point to the utility of adult genetic screens in the zebrafish in identifying essential developmental processes involved in human disease and in morphological evolution. PMID:18833299

  7. Sequencing Analysis of Mutant Allele $cdc$28-$srm$ of Protein Kinase CDC28 and Molecular Dynamics Study of Glycine-Rich Loop in Wild-Type and Mutant Allele G16S of CDK2 as Model

    CERN Document Server

    Koltovaya, N A; Kholmurodov, Kh T; Kretov, D A

    2005-01-01

    The central role that cyclin-dependent kinases play in the timing of cell division and the high incidence of genetic alteration of CDKs or deregulation of CDK inhibitors in a number of cancers make CDC28 of the yeast \\textit{Saccharomyces cerevisiae }very attractive model for studies of mechanisms of CDK regulation. Earlier it was found that certain gene mutations including \\textit{cdc28-srm} affect cell cycle progression, maintenance of different genetic structures and increase cell sensitivity to ionizing radiation. A~\\textit{cdc28-srm} mutation is not temperature-sensitive mutation and differs from the known \\textit{cdc28-ts }mutations because it has the evident phenotypic manifestations at 30 $^{\\circ}$C. Sequencing analysis of \\textit{cdc28-srm} revealed a single nucleotide substitution G20S. This is a third glycine in a conserved sequence GxGxxG in the G-rich loop positioned opposite the activation T-loop. Despite its demonstrated importance, the role of the G-loop has remained unclear. The crystal stru...

  8. Novel rapid genotyping assays for neuronal ceroid lipofuscinosis in Border Collie dogs and high frequency of the mutant allele in Japan.

    Science.gov (United States)

    Mizukami, Keijiro; Chang, Hye-Sook; Yabuki, Akira; Kawamichi, Takuji; Kawahara, Natsuko; Hayashi, Daisuke; Hossain, Mohammad A; Rahman, Mohammad M; Uddin, Mohammad M; Yamato, Osamu

    2011-11-01

    Neuronal ceroid lipofuscinosis (NCL) constitutes a group of recessively inherited lysosomal storage diseases that primarily affect neuronal cells. Such diseases share certain clinical and pathologic features in human beings and animals. Neuronal ceroid lipofuscinosis in Border Collie dogs was first detected in Australia in the 1980s, and the pathogenic mutation was shown to be a nonsense mutation (c.619C>T) in exon 4 in canine CLN5 gene. In the present study, novel rapid genotyping assays including polymerase chain reaction (PCR)-restriction fragment length polymorphism, PCR primer-induced restriction analysis, mutagenically separated PCR, and real-time PCR with TaqMan minor groove binder probes, were developed. The utility of microchip electrophoresis was also evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies in Japan using these assays to determine the current allele frequency in Japan, providing information to control and prevent this disease in the next stage. All assays developed in the current study are available to discriminate these genotypes, and microchip electrophoresis showed a timesaving advantage over agarose gel electrophoresis. Of all assays, real-time PCR was the most suitable for large-scale examination because of its high throughput. The genotyping survey demonstrated that the carrier frequency was 8.1%. This finding suggested that the mutant allele frequency of NCL in Border Collies is high enough in Japan that measures to control and prevent the disease would be warranted. The genotyping assays developed in the present study could contribute to the prevention of NCL in Border Collies.

  9. Molecular footprints reveal the impact of the protective HLA-A*03 allele in hepatitis C virus infection.

    LENUS (Irish Health Repository)

    Fitzmaurice, Karen

    2012-02-01

    BACKGROUND AND AIMS: CD8 T cells are central to the control of hepatitis C virus (HCV) although the key features of a successful CD8 T cell response remain to be defined. In a cohort of Irish women infected by a single source, a strong association between viral clearance and the human lecucocyte (HLA)-A*03 allele has been described, and the aim of this study was to define the protective nature of the associated CD8 T cell response. METHODS: A sequence-led approach was used to identify HLA-A*03-restricted epitopes. We examine the CD8 T cell response associated with this gene and address the likely mechanism underpinning this protective effect in this special cohort, using viral sequencing, T cell assays and analysis of fitness of viral mutants. RESULTS: A strong \\'HLA footprint\\' in a novel NS3 epitope (TVYHGAGTK) was observed. A lysine (K) to arginine (R) substitution at position 9 (K1088R) was seen in a significant number of A*03-positive patients (9\\/12) compared with the control group (1\\/33, p=0.0003). Threonine (T) was also substituted with alanine (A) at position 8 (T1087A) more frequently in A*03-positive patients (6\\/12) compared with controls (2\\/33, p=0.01), and the double substitution of TK to AR was also observed predominantly in HLA-A*03-positive patients (p=0.004). Epitope-specific CD8 T cell responses were observed in 60% of patients three decades after exposure and the mutants selected in vivo impacted on recognition in vitro. Using HCV replicons matched to the viral sequences, viral fitness was found to be markedly reduced by the K1088R substitution but restored by the second substitution T1087A. CONCLUSIONS: It is proposed that at least part of the protective effect of HLA-A*03 results from targeting of this key epitope in a functional site: the requirement for two mutations to balance fitness and escape provides an initial host advantage. This study highlights the potential protective impact of common HLA-A alleles against persistent

  10. Analysis of Mycobacterium avium subsp. paratuberculosis mutant libraries reveals loci-dependent transcription biases and strategies to novel mutant discovery

    Science.gov (United States)

    Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne’s disease in ruminants and it has been implicated as a cause of Crohn’s disease in humans. The generation of comprehensive random mutant banks by transposon mutagenesis is a fundamental wide genomic technology utilized...

  11. Short alleles revealed by PCR demonstrate no heterozygote deficiency at minisatellite loci D1S7, D7S21, and D12S11

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, S.; Castro, A.; Fernandez-Fernandez, I.; Pancorbo, M.M. de [Universidad del Pais Vasco, Vizcaya (Spain)

    1997-02-01

    Short VNTR alleles that go undetected after conventional Southern blot hybridization may constitute an alternative explanation for the heterozygosity deficiency observed at some minisatellite loci. To examine this hypothesis, we have employed a screening procedure based on PCR amplification of those individuals classified as homozygotes in our databases for the loci D1S7, D7S21, and D12S11. The results obtained indicate that the frequency of these short alleles is related to the heterozygosity deficiency observed. For the most polymorphic locus, D1S7, {approximately}60% of those individuals previously classified as homozygotes were in fact heterozygotes for a short allele. After the inclusion of these new alleles, the agreement between observed and expected heterozygosity, along with other statistical tests employed, provide additional evidence for lack of population substructuring. Comparisons of allele frequency distributions reveal greater differences between racial groups than between closely related populations. 45 refs., 3 figs., 6 tabs.

  12. Unexpected allelic heterogeneity and spectrum of mutations in Fowler syndrome revealed by next-generation exome sequencing.

    Science.gov (United States)

    Lalonde, Emilie; Albrecht, Steffen; Ha, Kevin C H; Jacob, Karine; Bolduc, Nathalie; Polychronakos, Constantin; Dechelotte, Pierre; Majewski, Jacek; Jabado, Nada

    2010-08-01

    Protein coding genes constitute approximately 1% of the human genome but harbor 85% of the mutations with large effects on disease-related traits. Therefore, efficient strategies for selectively sequencing complete coding regions (i.e., "whole exome") have the potential to contribute our understanding of human diseases. We used a method for whole-exome sequencing coupling Agilent whole-exome capture to the Illumina DNA-sequencing platform, and investigated two unrelated fetuses from nonconsanguineous families with Fowler Syndrome (FS), a stereotyped phenotype lethal disease. We report novel germline mutations in feline leukemia virus subgroup C cellular-receptor-family member 2, FLVCR2, which has recently been shown to cause FS. Using this technology, we identified three types of genetic abnormalities: point-mutations, insertions-deletions, and intronic splice-site changes (first pathogenic report using this technology), in the fetuses who both were compound heterozygotes for the disease. Although revealing a high level of allelic heterogeneity and mutational spectrum in FS, this study further illustrates the successful application of whole-exome sequencing to uncover genetic defects in rare Mendelian disorders. Of importance, we show that we can identify genes underlying rare, monogenic and recessive diseases using a limited number of patients (n=2), in the absence of shared genetic heritage and in the presence of allelic heterogeneity.

  13. A Δ11 desaturase gene genealogy reveals two divergent allelic classes within the European corn borer (Ostrinia nubilalis

    Directory of Open Access Journals (Sweden)

    Harrison Richard G

    2010-04-01

    Full Text Available Abstract Background Moth pheromone mating systems have been characterized at the molecular level, allowing evolutionary biologists to study how changes in protein sequence or gene expression affect pheromone phenotype, patterns of mating, and ultimately, the formation of barriers to gene exchange. Recent studies of Ostrinia pheromones have focused on the diversity of sex pheromone desaturases and their role in the specificity of pheromone production. Here we produce a Δ11 desaturase genealogy within Ostrinia nubilalis. We ask what has been the history of this gene, and whether this history suggests that changes in Δ11 desaturase have been involved in the divergence of the E and Z O. nubilalis pheromone strains. Results The Δ11 desaturase gene genealogy does not differentiate O. nubilalis pheromone strains. However, we find two distinct clades, separated by 2.9% sequence divergence, that do not sort with pheromone strain, geographic origin, or emergence time. We demonstrate that these clades do not represent gene duplicates, but rather allelic variation at a single gene locus. Conclusions Analyses of patterns of variation at the Δ11 desaturase gene in ECB suggest that this enzyme does not contribute to reproductive isolation between pheromone strains (E and Z. However, our genealogy reveals two deeply divergent allelic classes. Standing variation at loci that contribute to mate choice phenotypes may permit novel pheromone mating systems to arise in the presence of strong stabilizing selection.

  14. Lineage tracing of genome-edited alleles reveals high fidelity axolotl limb regeneration.

    Science.gov (United States)

    Flowers, Grant Parker; Sanor, Lucas D; Crews, Craig M

    2017-09-16

    Salamanders are unparalleled among tetrapods in their ability to regenerate many structures, including entire limbs, and the study of this ability may provide insights into human regenerative therapies. The complex structure of the limb poses challenges to the investigation of the cellular and molecular basis of its regeneration. Using CRISPR/Cas, we genetically labelled unique cell lineages within the developing axolotl embryo and tracked the frequency of each lineage within amputated and fully regenerated limbs. This allowed us, for the first time, to assess the contributions of multiple low frequency cell lineages to the regenerating limb at once. Our comparisons reveal that regenerated limbs are high fidelity replicas of the originals even after repeated amputations.

  15. Structure and function of starch and resistant starch from corn with different doses of mutant amylose-extender and floury-1 alleles.

    Science.gov (United States)

    Yao, Ni; Paez, Alix V; White, Pamela J

    2009-03-11

    Four corn types with different doses of mutant amylose-extender (ae) and floury-1 (fl1) alleles, in the endosperm, including no. 1, aeaeae; no. 2, fl1fl1fl1; no. 3, aeaefl1; and no. 4, fl1fl1ae, were developed for use in making Hispanic food products with high resistant starch (RS) content. The RS percentages in the native starch (NS) of 1-4 were 55.2, 1.1, 5.7, and 1.1%, respectively. All NS were evaluated for pasting properties with a rapid viscoanalyzer (RVA) and for thermal properties with a differential scanning calorimeter (DSC). NS 1 had a low peak viscosity (PV) caused by incomplete gelatinization, whereas NS 3 had the greatest PV and breakdown of all four starch types. On the DSC, NS 2 had the lowest onset temperature and greatest enthalpy. NS 1 and 3 had similar onset and peak temperatures, both higher than those of NS 2 and 4. The gel strength of NS heated with a RVA was evaluated by using a texture analyzer immediately after RVA heating (fresh, RVA-F) and after the gel had been stored at 4 degrees C for 10 days (retrograded, RVA-R). NS 1 gel was watery and had the lowest strength (30 g) among starch gel types. NS 3 gel, although exhibiting syneresis, had greater gel strength than NS 2 and 4. The structures of the NS, the RS isolated from the NS (RS-NS), the RS isolated from RVA-F (RS-RVA-F), and the RS isolated from RVA-R (RS-RVA-R) were evaluated by using size exclusion chromatography. NS 1 had a greater percentage of amylose (AM) (58.3%) than the other NS (20.4-26.8%). The RS from all NS types (RS-NS) had a lower percentage of amylopectin (AP) and a greater percentage of low molecular weight (MW) AM than was present in the original NS materials. The RS-RVA-R from all starches had no AP or high MW AM. The percentages of longer chain lengths (DP 35-60) of NS were greater in 1 and 3 than in 2 and 4, and the percentages of smaller chain lengths (DP 10-20) were greater in 2 and 4 than in 1 and 3. In general, NS 3 seemed to have inherited some pasting

  16. Variant allele frequency enrichment analysis in vitro reveals sonic hedgehog pathway to impede sustained temozolomide response in GBM.

    Science.gov (United States)

    Biswas, Nidhan K; Chandra, Vikas; Sarkar-Roy, Neeta; Das, Tapojyoti; Bhattacharya, Rabindra N; Tripathy, Laxmi N; Basu, Sunandan K; Kumar, Shantanu; Das, Subrata; Chatterjee, Ankita; Mukherjee, Ankur; Basu, Pryiadarshi; Maitra, Arindam; Chattopadhyay, Ansuman; Basu, Analabha; Dhara, Surajit

    2015-01-21

    Neoplastic cells of Glioblastoma multiforme (GBM) may or may not show sustained response to temozolomide (TMZ) chemotherapy. We hypothesize that TMZ chemotherapy response in GBM is predetermined in its neoplastic clones via a specific set of mutations that alter relevant pathways. We describe exome-wide enrichment of variant allele frequencies (VAFs) in neurospheres displaying contrasting phenotypes of sustained versus reversible TMZ-responses in vitro. Enrichment of VAFs was found on genes ST5, RP6KA1 and PRKDC in cells showing sustained TMZ-effect whereas on genes FREM2, AASDH and STK36, in cells showing reversible TMZ-effect. Ingenuity pathway analysis (IPA) revealed that these genes alter cell-cycle, G2/M-checkpoint-regulation and NHEJ pathways in sustained TMZ-effect cells whereas the lysine-II&V/phenylalanine degradation and sonic hedgehog (Hh) pathways in reversible TMZ-effect cells. Next, we validated the likely involvement of the Hh-pathway in TMZ-response on additional GBM neurospheres as well as on GBM patients, by extracting RNA-sequencing-based gene expression data from the TCGA-GBM database. Finally, we demonstrated TMZ-sensitization of a TMZ non-responder neurosphere in vitro by treating them with the FDA-approved pharmacological Hh-pathway inhibitor vismodegib. Altogether, our results indicate that the Hh-pathway impedes sustained TMZ-response in GBM and could be a potential therapeutic target to enhance TMZ-response in this malignancy.

  17. Next-generation sequencing can reveal in vitro-generated PCR crossover products: some artifactual sequences correspond to HLA alleles in the IMGT/HLA database.

    Science.gov (United States)

    Holcomb, C L; Rastrou, M; Williams, T C; Goodridge, D; Lazaro, A M; Tilanus, M; Erlich, H A

    2014-01-01

    The high-resolution human leukocyte antigen (HLA) genotyping assay that we developed using 454 sequencing and Conexio software uses generic polymerase chain reaction (PCR) primers for DRB exon 2. Occasionally, we observed low abundance DRB amplicon sequences that resulted from in vitro PCR 'crossing over' between DRB1 and DRB3/4/5. These hybrid sequences, revealed by the clonal sequencing property of the 454 system, were generally observed at a read depth of 5%-10% of the true alleles. They usually contained at least one mismatch with the IMGT/HLA database, and consequently, were easily recognizable and did not cause a problem for HLA genotyping. Sometimes, however, these artifactual sequences matched a rare allele and the automatic genotype assignment was incorrect. These observations raised two issues: (1) could PCR conditions be modified to reduce such artifacts? and (2) could some of the rare alleles listed in the IMGT/HLA database be artifacts rather than true alleles? Because PCR crossing over occurs during late cycles of PCR, we compared DRB genotypes resulting from 28 and (our standard) 35 cycles of PCR. For all 21 cell line DNAs amplified for 35 cycles, crossover products were detected. In 33% of the cases, these hybrid sequences corresponded to named alleles. With amplification for only 28 cycles, these artifactual sequences were not detectable. To investigate whether some rare alleles in the IMGT/HLA database might be due to PCR artifacts, we analyzed four samples obtained from the investigators who submitted the sequences. In three cases, the sequences were generated from true alleles. In one case, our 454 sequencing revealed an error in the previously submitted sequence. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. A Landscape of Therapeutic Cooperativity in KRAS Mutant Cancers Reveals Principles for Controlling Tumor Evolution

    OpenAIRE

    Grace R. Anderson; Peter S. Winter; Kevin H. Lin; Daniel P. Nussbaum; Merve Cakir; Elizabeth M. Stein; Ryan S. Soderquist; Lorin Crawford; Jim C. Leeds; Rachel Newcomb; Priya Stepp; Catherine Yip; Suzanne E. Wardell; Jennifer P. Tingley; Moiez Ali

    2017-01-01

    Combinatorial inhibition of effector and feedback pathways is a promising treatment strategy for KRAS mutant cancers. However, the particular pathways that should be targeted to optimize therapeutic responses are unclear. Using CRISPR/Cas9, we systematically mapped the pathways whose inhibition cooperates with drugs targeting the KRAS effectors MEK, ERK, and PI3K. By performing 70 screens in models of KRAS mutant colorectal, lung, ovarian, and pancreas cancers, we uncovered universal and tiss...

  19. Transcriptomic profiling-based mutant screen reveals three new transcription factors mediating menadione resistance in Neurospora crassa.

    Science.gov (United States)

    Zhu, Jufen; Yu, Xinxu; Xie, Baogui; Gu, Xiaokui; Zhang, Zhenying; Li, Shaojie

    2013-06-01

    To gain insight into the regulatory mechanisms of oxidative stress responses in filamentous fungi, the genome-wide transcriptional response of Neurospora crassa to menadione was analysed by digital gene expression (DGE) profiling, which identified 779 upregulated genes and 576 downregulated genes. Knockout mutants affecting 130 highly-upregulated genes were tested for menadione sensitivity, which revealed that loss of the transcription factor siderophore regulation (SRE) (a transcriptional repressor for siderophore biosynthesis), catatase-3, cytochrome c peroxidase or superoxide dismutase 1 copper chaperone causes hypersensitivity to menadione. Deletion of sre dramatically increased transcription of the siderophore biosynthesis gene ono and the siderophore iron transporter gene sit during menadione stress, suggesting that SRE is required for repression of iron uptake under oxidative stress conditions. Contrary to its phenotype, the sre deletion mutant showed higher transcriptional levels of genes encoding reactive oxygen species (ROS) scavengers than wild type during menadione stress, which implies that the mutant suffers a higher level of oxidative stress than wild type. Uncontrolled iron uptake in the sre mutant might exacerbate cellular oxidative stress. This is the first report of a negative regulator of iron assimilation participating in the fungal oxidative stress response. In addition to SRE, eight other transcription factor genes were also menadione-responsive but their single gene knockout mutants showed wild-type menadione sensitivity. Two of them, named as mit-2 (menadione induced transcription factor-2) and mit-4 (menadione induced transcription factor-4), were selected for double mutant analysis. The double mutant was hypersensitive to menadione. Similarly, the double mutation of mit-2 and sre also had additive effects on menadione sensitivity, suggesting multiple transcription factors mediate oxidative stress resistance in an additive manner

  20. GWAS analysis using interspecific backcross progenies reveals superior blue catfish alleles responsible for strong resistance against enteric septicemia of catfish.

    Science.gov (United States)

    Tan, Suxu; Zhou, Tao; Wang, Wenwen; Jin, Yulin; Wang, Xiaozhu; Geng, Xin; Luo, Jian; Yuan, Zihao; Yang, Yujia; Shi, Huitong; Gao, Dongya; Dunham, Rex; Liu, Zhanjiang

    2018-05-08

    Infectious diseases pose significant threats to the catfish industry. Enteric septicemia of catfish (ESC) caused by Edwardsiella ictaluri is the most devastating disease for catfish aquaculture, causing huge economic losses annually. Channel catfish and blue catfish exhibit great contrast in resistance against ESC, with channel catfish being highly susceptible and blue catfish being highly resistant. As such, the interspecific backcross progenies provide an ideal system for the identification of quantitative trait locus (QTL). We previously reported one significant QTL on linkage group (LG) 1 using the third-generation backcrosses, but the number of founders used to make the second- and third-generation backcross progenies was very small. Although the third-generation backcross progenies provided a greater power for fine mapping than the first-generation backcrosses, some major QTL for disease resistance may have been missing due to the small numbers of founders used to produce the higher generation backcrosses. In this study, we performed a genome-wide association study using first-generation backcrosses with the catfish 690 K SNP arrays to identify additional ESC disease resistance QTL, especially those at the species level. Two genomic regions on LG1 and LG23 were determined to be significantly associated with ESC resistance as revealed by a mixed linear model and family-based association test. Examination of the resistance alleles indicated their origin from blue catfish, indicating that at least two major disease resistance loci exist among blue catfish populations. Upon further validation, markers linked with major ESC disease resistance QTL should be useful for marker-assisted introgression, allowing development of highly ESC resistant breeds of catfish.

  1. Tyrosyl-DNA Phosphodiesterase I Catalytic Mutants Reveal an Alternative Nucleophile That Can Catalyze Substrate Cleavage*

    Science.gov (United States)

    Comeaux, Evan Q.; Cuya, Selma M.; Kojima, Kyoko; Jafari, Nauzanene; Wanzeck, Keith C.; Mobley, James A.; Bjornsti, Mary-Ann; van Waardenburg, Robert C. A. M.

    2015-01-01

    Tyrosyl-DNA phosphodiesterase I (Tdp1) catalyzes the repair of 3′-DNA adducts, such as the 3′-phosphotyrosyl linkage of DNA topoisomerase I to DNA. Tdp1 contains two conserved catalytic histidines: a nucleophilic His (Hisnuc) that attacks DNA adducts to form a covalent 3′-phosphohistidyl intermediate and a general acid/base His (Hisgab), which resolves the Tdp1-DNA linkage. A Hisnuc to Ala mutant protein is reportedly inactive, whereas the autosomal recessive neurodegenerative disease SCAN1 has been attributed to the enhanced stability of the Tdp1-DNA intermediate induced by mutation of Hisgab to Arg. However, here we report that expression of the yeast HisnucAla (H182A) mutant actually induced topoisomerase I-dependent cytotoxicity and further enhanced the cytotoxicity of Tdp1 Hisgab mutants, including H432N and the SCAN1-related H432R. Moreover, the HisnucAla mutant was catalytically active in vitro, albeit at levels 85-fold less than that observed with wild type Tdp1. In contrast, the HisnucPhe mutant was catalytically inactive and suppressed Hisgab mutant-induced toxicity. These data suggest that the activity of another nucleophile when Hisnuc is replaced with residues containing a small side chain (Ala, Asn, and Gln), but not with a bulky side chain. Indeed, genetic, biochemical, and mass spectrometry analyses show that a highly conserved His, immediately N-terminal to Hisnuc, can act as a nucleophile to catalyze the formation of a covalent Tdp1-DNA intermediate. These findings suggest that the flexibility of Tdp1 active site residues may impair the resolution of mutant Tdp1 covalent phosphohistidyl intermediates and provide the rationale for developing chemotherapeutics that stabilize the covalent Tdp1-DNA intermediate. PMID:25609251

  2. Systematic screen for mutants resistant to TORC1 inhibition in fission yeast reveals genes involved in cellular ageing and growth

    Directory of Open Access Journals (Sweden)

    Charalampos Rallis

    2014-01-01

    Target of rapamycin complex 1 (TORC1, which controls growth in response to nutrients, promotes ageing in multiple organisms. The fission yeast Schizosaccharomyces pombe emerges as a valuable genetic model system to study TORC1 function and cellular ageing. Here we exploited the combinatorial action of rapamycin and caffeine, which inhibit fission yeast growth in a TORC1-dependent manner. We screened a deletion library, comprising ∼84% of all non-essential fission yeast genes, for drug-resistant mutants. This screen identified 33 genes encoding functions such as transcription, kinases, mitochondrial respiration, biosynthesis, intra-cellular trafficking, and stress response. Among the corresponding mutants, 5 showed shortened and 21 showed increased maximal chronological lifespans; 15 of the latter mutants showed no further lifespan increase with rapamycin and might thus represent key targets downstream of TORC1. We pursued the long-lived sck2 mutant with additional functional analyses, revealing that the Sck2p kinase functions within the TORC1 network and is required for normal cell growth, global protein translation, and ribosomal S6 protein phosphorylation in a nutrient-dependent manner. Notably, slow cell growth was associated with all long-lived mutants while oxidative-stress resistance was not.

  3. Genetic analysis of tachyzoite to bradyzoite differentiation mutants in Toxoplasma gondii reveals a hierarchy of gene induction.

    Science.gov (United States)

    Singh, Upinder; Brewer, Jeremy L; Boothroyd, John C

    2002-05-01

    Developmental switching in Toxoplasma gondii, from the virulent tachyzoite to the relatively quiescent bradyzoite stage, is responsible for disease propagation and reactivation. We have generated tachyzoite to bradyzoite differentiation (Tbd-) mutants in T. gondii and used these in combination with a cDNA microarray to identify developmental pathways in bradyzoite formation. Four independently generated Tbd- mutants were analysed and had defects in bradyzoite development in response to multiple bradyzoite-inducing conditions, a stable phenotype after in vivo passages and a markedly reduced brain cyst burden in a murine model of chronic infection. Transcriptional profiles of mutant and wild-type parasites, growing under bradyzoite conditions, revealed a hierarchy of developmentally regulated genes, including many bradyzoite-induced genes whose transcripts were reduced in all mutants. A set of non-developmentally regulated genes whose transcripts were less abundant in Tbd- mutants were also identified. These may represent genes that mediate downstream effects and/or whose expression is dependent on the same transcription factors as the bradyzoite-induced set. Using these data, we have generated a model of transcription regulation during bradyzoite development in T. gondii. Our approach shows the utility of this system as a model to study developmental biology in single-celled eukaryotes including protozoa and fungi.

  4. Distinct Rayleigh scattering from hot spot mutant p53 proteins reveals cancer cells.

    Science.gov (United States)

    Jun, Ho Joon; Nguyen, Anh H; Kim, Yeul Hong; Park, Kyong Hwa; Kim, Doyoun; Kim, Kyeong Kyu; Sim, Sang Jun

    2014-07-23

    The scattering of light redirects and resonances when an electromagnetic wave interacts with electrons orbits in the hot spot core protein and oscillated electron of the gold nanoparticles (AuNP). This report demonstrates convincingly that resonant Rayleigh scattering generated from hot spot mutant p53 proteins is correspondence to cancer cells. Hot spot mutants have unique local electron density changes that affect specificity of DNA binding affinity compared with wild types. Rayleigh scattering changes introduced by hot-spot mutations were monitored by localized surface plasmon resonance (LSPR) shift changes. The LSPR λmax shift for hot-spot mutants ranged from 1.7 to 4.2 nm for mouse samples and from 0.64 nm to 2.66 nm for human samples, compared to 9.6 nm and 15 nm for wild type and mouse and human proteins, respectively with a detection sensitivity of p53 concentration at 17.9 nM. It is interesting that hot-spot mutants, which affect only interaction with DNA, launches affinitive changes as considerable as wild types. These changes propose that hot-spot mutants p53 proteins can be easily detected by local electron density alterations that disturbs the specificity of DNA binding of p53 core domain on the surface of the DNA probed-nanoplasmonic sensor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. [Mutant alleles associated to chloroquine and sulfadoxine-pyrimethanime resistance in Plasmodium falciparum of the Ecuador-Peru and Ecuador-Colombia borders].

    Science.gov (United States)

    Arróspide, Nancy; Hijar-Guerra, Gisely; de Mora, Doménica; Diaz-Cortéz, César Eduardo; Veloz-Perez, Raúl; Gutierrez, Sonia; Cabezas-Sánchez, César

    2014-04-01

    The frequency of mutations in pfCRT and DHFR/DHPS genes of Plasmodium falciparum associated with resistance to chloroquine and sulfadoxine-pyrimethamine was evaluated in 83 strains from the districts of Esmeralda and Machala, located on the borders of Ecuador-Peru and Ecuador-Colombia in 2002. Polymerase chain reaction (PCR), conventional and its variants, was used. Mutations in the pfCRT gene were found in more than 90% of the samples from Esmeralda and Machala. For the DHFR gene, 90% of the strains were mutant samples from Esmeralda, 3 were double mutations and 1 was a triple mutation. In Machala, 25% were simple mutant forms and 75% mixed mutant forms (wild forms/mutant). In conclusion, resistance to chloroquine has been fixed in strains carrying K76T pfCRT mutation, whereas genetic imprinting for resistance to pyrimethamine is evolving, particularly in the district of Esmeralda.

  6. Zebrafish model of tuberous sclerosis complex reveals cell-autonomous and non-cell-autonomous functions of mutant tuberin

    Directory of Open Access Journals (Sweden)

    Seok-Hyung Kim

    2011-03-01

    Tuberous sclerosis complex (TSC is an autosomal dominant disease caused by mutations in either the TSC1 (encodes hamartin or TSC2 (encodes tuberin genes. Patients with TSC have hamartomas in various organs throughout the whole body, most notably in the brain, skin, eye, heart, kidney and lung. To study the development of hamartomas, we generated a zebrafish model of TSC featuring a nonsense mutation (vu242 in the tsc2 gene. This tsc2vu242 allele encodes a truncated Tuberin protein lacking the GAP domain, which is required for inhibition of Rheb and of the TOR kinase within TORC1. We show that tsc2vu242 is a recessive larval-lethal mutation that causes increased cell size in the brain and liver. Greatly elevated TORC1 signaling is observed in tsc2vu242/vu242 homozygous zebrafish, and is moderately increased in tsc2vu242/+ heterozygotes. Forebrain neurons are poorly organized in tsc2vu242/vu242 homozygous mutants, which have extensive gray and white matter disorganization and ectopically positioned cells. Genetic mosaic analyses demonstrate that tsc2 limits TORC1 signaling in a cell-autonomous manner. However, in chimeric animals, tsc2vu242/vu242 mutant cells also mislocalize wild-type host cells in the forebrain in a non-cell-autonomous manner. These results demonstrate a highly conserved role of tsc2 in zebrafish and establish a new animal model for studies of TSC. The finding of a non-cell-autonomous function of mutant cells might help explain the formation of brain hamartomas and cortical malformations in human TSC.

  7. Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

    KAUST Repository

    Fujii, Hiroaki

    2011-01-10

    Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved in osmotic stress signaling. However, due to functional redundancy, their contribution to osmotic stress responses remained unclear. In this report, we constructed an Arabidopsis line carrying mutations in all 10 members of the SnRK2 family. The decuple mutant snrk2.1/2/3/4/5/6/7/8/9/10 grew poorly under hyperosmotic stress conditions but was similar to the wild type in culture media in the absence of osmotic stress. The mutant was also defective in gene regulation and the accumulation of abscisic acid (ABA), proline, and inositol 1,4,5-trisphosphate under osmotic stress. In addition, analysis of mutants defective in the ABA-activated SnRK2s (snrk2.2/3/6) and mutants defective in the rest of the SnRK2s (snrk2.1/4/5/7/8/9/10) revealed that SnRK2s are a merging point of ABA-dependent and -independent pathways for osmotic stress responses. These results demonstrate critical functions of the SnRK2s in mediating osmotic stress signaling and tolerance.

  8. New genes of Xanthomonas citri subsp. citri involved in pathogenesis and adaptation revealed by a transposon-based mutant library.

    Science.gov (United States)

    Laia, Marcelo L; Moreira, Leandro M; Dezajacomo, Juliana; Brigati, Joice B; Ferreira, Cristiano B; Ferro, Maria I T; Silva, Ana C R; Ferro, Jesus A; Oliveira, Julio C F

    2009-01-16

    Citrus canker is a disease caused by the phytopathogens Xanthomonas citri subsp. citri, Xanthomonas fuscans subsp. aurantifolli and Xanthomonas alfalfae subsp. citrumelonis. The first of the three species, which causes citrus bacterial canker type A, is the most widely spread and severe, attacking all citrus species. In Brazil, this species is the most important, being found in practically all areas where citrus canker has been detected. Like most phytobacterioses, there is no efficient way to control citrus canker. Considering the importance of the disease worldwide, investigation is needed to accurately detect which genes are related to the pathogen-host adaptation process and which are associated with pathogenesis. Through transposon insertion mutagenesis, 10,000 mutants of Xanthomonas citri subsp. citri strain 306 (Xcc) were obtained, and 3,300 were inoculated in Rangpur lime (Citrus limonia) leaves. Their ability to cause citrus canker was analyzed every 3 days until 21 days after inoculation; a set of 44 mutants showed altered virulence, with 8 presenting a complete loss of causing citrus canker symptoms. Sequencing of the insertion site in all 44 mutants revealed that 35 different ORFs were hit, since some ORFs were hit in more than one mutant, with mutants for the same ORF presenting the same phenotype. An analysis of these ORFs showed that some encoded genes were previously known as related to pathogenicity in phytobacteria and, more interestingly, revealed new genes never implicated with Xanthomonas pathogenicity before, including hypothetical ORFs. Among the 8 mutants with no canker symptoms are the hrpB4 and hrpX genes, two genes that belong to type III secretion system (TTSS), two hypothetical ORFS and, surprisingly, the htrA gene, a gene reported as involved with the virulence process in animal-pathogenic bacteria but not described as involved in phytobacteria virulence. Nucleic acid hybridization using labeled cDNA probes showed that some of the

  9. Potent and selective antisense oligonucleotides targeting single-nucleotide polymorphisms in the Huntington disease gene / allele-specific silencing of mutant huntingtin

    DEFF Research Database (Denmark)

    Carroll, Jeffrey B; Warby, Simon C; Southwell, Amber L

    2011-01-01

    Huntington disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG-expansion in the huntingtin gene (HTT) that results in a toxic gain of function in the mutant huntingtin protein (mHTT). Reducing the expression of mHTT is therefore an attractive therapy for HD. However, wild...

  10. Novel CRISPR/Cas9 gene drive constructs reveal insights into mechanisms of resistance allele formation and drive efficiency in genetically diverse populations.

    Directory of Open Access Journals (Sweden)

    Jackson Champer

    2017-07-01

    Full Text Available A functioning gene drive system could fundamentally change our strategies for the control of vector-borne diseases by facilitating rapid dissemination of transgenes that prevent pathogen transmission or reduce vector capacity. CRISPR/Cas9 gene drive promises such a mechanism, which works by converting cells that are heterozygous for the drive construct into homozygotes, thereby enabling super-Mendelian inheritance. Although CRISPR gene drive activity has already been demonstrated, a key obstacle for current systems is their propensity to generate resistance alleles, which cannot be converted to drive alleles. In this study, we developed two CRISPR gene drive constructs based on the nanos and vasa promoters that allowed us to illuminate the different mechanisms by which resistance alleles are formed in the model organism Drosophila melanogaster. We observed resistance allele formation at high rates both prior to fertilization in the germline and post-fertilization in the embryo due to maternally deposited Cas9. Assessment of drive activity in genetically diverse backgrounds further revealed substantial differences in conversion efficiency and resistance rates. Our results demonstrate that the evolution of resistance will likely impose a severe limitation to the effectiveness of current CRISPR gene drive approaches, especially when applied to diverse natural populations.

  11. Cosegregation and functional analysis of mutant ABCR (ABCA4) alleles in families that manifest both Stargardt disease and age-related macular degeneration.

    Science.gov (United States)

    Shroyer, N F; Lewis, R A; Yatsenko, A N; Wensel, T G; Lupski, J R

    2001-11-01

    Mutations in ABCR (ABCA4) have been reported to cause a spectrum of autosomal recessively inherited retinopathies, including Stargardt disease (STGD), cone-rod dystrophy and retinitis pigmentosa. Individuals heterozygous for ABCR mutations may be predisposed to develop the multifactorial disorder age-related macular degeneration (AMD). We hypothesized that some carriers of STGD alleles have an increased risk to develop AMD. We tested this hypothesis in a cohort of families that manifest both STGD and AMD. With a direct-sequencing mutation detection strategy, we found that AMD-affected relatives of STGD patients are more likely to be carriers of pathogenic STGD alleles than predicted based on chance alone. We further investigated the role of AMD-associated ABCR mutations by testing for expression and ATP-binding defects in an in vitro biochemical assay. We found that mutations associated with AMD have a range of assayable defects ranging from no detectable defect to apparent null alleles. Of the 21 missense ABCR mutations reported in patients with AMD, 16 (76%) show abnormalities in protein expression, ATP-binding or ATPase activity. We infer that carrier relatives of STGD patients are predisposed to develop AMD.

  12. Novel ethyl methanesulfonate (EMS-induced null alleles of the Drosophila homolog of LRRK2 reveal a crucial role in endolysosomal functions and autophagy in vivo

    Directory of Open Access Journals (Sweden)

    Mark W. Dodson

    2014-12-01

    Full Text Available Mutations in LRRK2 cause a dominantly inherited form of Parkinson’s disease (PD and are the most common known genetic determinant of PD. Inhibitor-based therapies targeting LRRK2 have emerged as a key therapeutic strategy in PD; thus, understanding the consequences of inhibiting the normal cellular functions of this protein is vital. Despite much interest, the physiological functions of LRRK2 remain unclear. Several recent studies have linked the toxicity caused by overexpression of pathogenic mutant forms of LRRK2 to defects in the endolysosomal and autophagy pathways, raising the question of whether endogenous LRRK2 might play a role in these processes. Here, we report the characterization of multiple novel ethyl methanesulfonate (EMS-induced nonsense alleles in the Drosophila LRRK2 homolog, lrrk. Using these alleles, we show that lrrk loss-of-function causes striking defects in the endolysosomal and autophagy pathways, including the accumulation of markedly enlarged lysosomes that are laden with undigested contents, consistent with a defect in lysosomal degradation. lrrk loss-of-function also results in the accumulation of autophagosomes, as well as the presence of enlarged early endosomes laden with mono-ubiquitylated cargo proteins, suggesting an additional defect in lysosomal substrate delivery. Interestingly, the lysosomal abnormalities in these lrrk mutants can be suppressed by a constitutively active form of the small GTPase rab9, which promotes retromer-dependent recycling from late endosomes to the Golgi. Collectively, our data provides compelling evidence of a vital role for lrrk in lysosomal function and endolysosomal membrane transport in vivo, and suggests a link between lrrk and retromer-mediated endosomal recycling.

  13. Novel ethyl methanesulfonate (EMS)-induced null alleles of the Drosophila homolog of LRRK2 reveal a crucial role in endolysosomal functions and autophagy in vivo.

    Science.gov (United States)

    Dodson, Mark W; Leung, Lok K; Lone, Mohiddin; Lizzio, Michael A; Guo, Ming

    2014-12-01

    Mutations in LRRK2 cause a dominantly inherited form of Parkinson's disease (PD) and are the most common known genetic determinant of PD. Inhibitor-based therapies targeting LRRK2 have emerged as a key therapeutic strategy in PD; thus, understanding the consequences of inhibiting the normal cellular functions of this protein is vital. Despite much interest, the physiological functions of LRRK2 remain unclear. Several recent studies have linked the toxicity caused by overexpression of pathogenic mutant forms of LRRK2 to defects in the endolysosomal and autophagy pathways, raising the question of whether endogenous LRRK2 might play a role in these processes. Here, we report the characterization of multiple novel ethyl methanesulfonate (EMS)-induced nonsense alleles in the Drosophila LRRK2 homolog, lrrk. Using these alleles, we show that lrrk loss-of-function causes striking defects in the endolysosomal and autophagy pathways, including the accumulation of markedly enlarged lysosomes that are laden with undigested contents, consistent with a defect in lysosomal degradation. lrrk loss-of-function also results in the accumulation of autophagosomes, as well as the presence of enlarged early endosomes laden with mono-ubiquitylated cargo proteins, suggesting an additional defect in lysosomal substrate delivery. Interestingly, the lysosomal abnormalities in these lrrk mutants can be suppressed by a constitutively active form of the small GTPase rab9, which promotes retromer-dependent recycling from late endosomes to the Golgi. Collectively, our data provides compelling evidence of a vital role for lrrk in lysosomal function and endolysosomal membrane transport in vivo, and suggests a link between lrrk and retromer-mediated endosomal recycling. © 2014. Published by The Company of Biologists Ltd.

  14. RNA-Seq using two populations reveals genes and alleles controlling wood traits and growth in Eucalyptus nitens.

    Directory of Open Access Journals (Sweden)

    Saravanan Thavamanikumar

    Full Text Available Eucalyptus nitens is a perennial forest tree species grown mainly for kraft pulp production in many parts of the world. Kraft pulp yield (KPY is a key determinant of plantation profitability and increasing the KPY of trees grown in plantations is a major breeding objective. To speed up the breeding process, molecular markers that can predict KPY are desirable. To achieve this goal, we carried out RNA-Seq studies on trees at extremes of KPY in two different trials to identify genes and alleles whose expression correlated with KPY. KPY is positively correlated with growth measured as diameter at breast height (DBH in both trials. In total, six RNA bulks from two treatments were sequenced on an Illumina HiSeq platform. At 5% false discovery rate level, 3953 transcripts showed differential expression in the same direction in both trials; 2551 (65% were down-regulated and 1402 (35% were up-regulated in low KPY samples. The genes up-regulated in low KPY trees were largely involved in biotic and abiotic stress response reflecting the low growth among low KPY trees. Genes down-regulated in low KPY trees mainly belonged to gene categories involved in wood formation and growth. Differential allelic expression was observed in 2103 SNPs (in 1068 genes and of these 640 SNPs (30% occurred in 313 unique genes that were also differentially expressed. These SNPs may represent the cis-acting regulatory variants that influence total gene expression. In addition we also identified 196 genes which had Ka/Ks ratios greater than 1.5, suggesting that these genes are under positive selection. Candidate genes and alleles identified in this study will provide a valuable resource for future association studies aimed at identifying molecular markers for KPY and growth.

  15. YY1 binding association with sex-biased transcription revealed through X-linked transcript levels and allelic binding analyses.

    Science.gov (United States)

    Chen, Chih-Yu; Shi, Wenqiang; Balaton, Bradley P; Matthews, Allison M; Li, Yifeng; Arenillas, David J; Mathelier, Anthony; Itoh, Masayoshi; Kawaji, Hideya; Lassmann, Timo; Hayashizaki, Yoshihide; Carninci, Piero; Forrest, Alistair R R; Brown, Carolyn J; Wasserman, Wyeth W

    2016-11-18

    Sex differences in susceptibility and progression have been reported in numerous diseases. Female cells have two copies of the X chromosome with X-chromosome inactivation imparting mono-allelic gene silencing for dosage compensation. However, a subset of genes, named escapees, escape silencing and are transcribed bi-allelically resulting in sexual dimorphism. Here we conducted in silico analyses of the sexes using human datasets to gain perspectives into such regulation. We identified transcription start sites of escapees (escTSSs) based on higher transcription levels in female cells using FANTOM5 CAGE data. Significant over-representations of YY1 transcription factor binding motif and ChIP-seq peaks around escTSSs highlighted its positive association with escapees. Furthermore, YY1 occupancy is significantly biased towards the inactive X (Xi) at long non-coding RNA loci that are frequent contacts of Xi-specific superloops. Our study suggests a role for YY1 in transcriptional activity on Xi in general through sequence-specific binding, and its involvement at superloop anchors.

  16. Segmental allotetraploidy and allelic interactions in buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.) as revealed by genome mapping.

    Science.gov (United States)

    Jessup, R W; Burson, B L; Burow, O; Wang, Y W; Chang, C; Li, Z; Paterson, A H; Hussey, M A

    2003-04-01

    Linkage analyses increasingly complement cytological and traditional plant breeding techniques by providing valuable information regarding genome organization and transmission genetics of complex polyploid species. This study reports a genome map of buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.). Maternal and paternal maps were constructed with restriction fragment length polymorphisms (RFLPs) segregating in 87 F1 progeny from an intraspecific cross between two heterozygous genotypes. A survey of 862 heterologous cDNAs and gDNAs from across the Poaceae, as well as 443 buffelgrass cDNAs, yielded 100 and 360 polymorphic probes, respectively. The maternal map included 322 RFLPs, 47 linkage groups, and 3464 cM, whereas the paternal map contained 245 RFLPs, 42 linkage groups, and 2757 cM. Approximately 70 to 80% of the buffelgrass genome was covered, and the average marker spacing was 10.8 and 11.3 cM on the respective maps. Preferential pairing was indicated between many linkage groups, which supports cytological reports that buffelgrass is a segmental allotetraploid. More preferential pairing (disomy) was found in the maternal than paternal parent across linkage groups (55 vs. 38%) and loci (48 vs. 15%). Comparison of interval lengths in 15 allelic bridges indicated significantly less meiotic recombination in paternal gametes. Allelic interactions were detected in four regions of the maternal map and were absent in the paternal map.

  17. The maize milkweed pod1 mutant reveals a mechanism to modify organ morphology.

    Science.gov (United States)

    Johnston, Robyn; Candela, Héctor; Hake, Sarah; Foster, Toshi

    2010-07-01

    Plant lateral organs, such as leaves, have three primary axes of growth-proximal-distal, medial--lateral and adaxial-abaxial (dorsal-ventral). Although most leaves are planar, modified leaf forms, such as the bikeeled grass prophyll, can be found in nature. A detailed examination of normal prophyll development indicates that polarity is established differently in the keels than in other parts of the prophyll. Analysis of the maize HD-ZIPIII gene rolled leaf1 (rld1) suggests that altered expression patterns are responsible for keel outgrowth. Recessive mutations in the maize (Zea mays) KANADI (KAN) gene milkweed pod1 (mwp1), which promotes abaxial cell identity, strongly affect development of the prophyll and silks (fused carpels). The prophyll is reduced to two unfused midribs and the silks are narrow and misshapen. Our data indicate that the prophyll and other fused organs are particularly sensitive to disruptions in adaxial-abaxial polarity. In addition, lateral and proximal-distal growth of most lateral organs is reduced in the mwp1-R mutant, supporting a role for the adaxial-abaxial boundary in promoting growth along both axes. We propose that the adaxial-abaxial patterning mechanism has been co-opted during evolution to generate diverse organ morphologies. (c) 2010 Wiley-Liss, Inc.

  18. Transcriptome Analysis of Polyhydroxybutyrate Cycle Mutants Reveals Discrete Loci Connecting Nitrogen Utilization and Carbon Storage in Sinorhizobium meliloti.

    Science.gov (United States)

    D'Alessio, Maya; Nordeste, Ricardo; Doxey, Andrew C; Charles, Trevor C

    2017-01-01

    Polyhydroxybutyrate (PHB) and glycogen polymers are produced by bacteria as carbon storage compounds under unbalanced growth conditions. To gain insights into the transcriptional mechanisms controlling carbon storage in Sinorhizobium meliloti , we investigated the global transcriptomic response to the genetic disruption of key genes in PHB synthesis and degradation and in glycogen synthesis. Under both nitrogen-limited and balanced growth conditions, transcriptomic analysis was performed with genetic mutants deficient in PHB synthesis ( phbA , phbB , phbAB , and phbC ), PHB degradation ( bdhA , phaZ , and acsA2 ), and glycogen synthesis ( glgA1 ). Three distinct genomic regions of the pSymA megaplasmid exhibited altered expression in the wild type and the PHB cycle mutants that was not seen in the glycogen synthesis mutant. An Fnr family transcriptional motif was identified in the upstream regions of a cluster of genes showing similar transcriptional patterns across the mutants. This motif was found at the highest density in the genomic regions with the strongest transcriptional effect, and the presence of this motif upstream of genes in these regions was significantly correlated with decreased transcript abundance. Analysis of the genes in the pSymA regions revealed that they contain a genomic overrepresentation of Fnr family transcription factor-encoding genes. We hypothesize that these loci, containing mostly nitrogen utilization, denitrification, and nitrogen fixation genes, are regulated in response to the intracellular carbon/nitrogen balance. These results indicate a transcriptional regulatory association between intracellular carbon levels (mediated through the functionality of the PHB cycle) and the expression of nitrogen metabolism genes. IMPORTANCE The ability of bacteria to store carbon and energy as intracellular polymers uncouples cell growth and replication from nutrient uptake and provides flexibility in the use of resources as they are available to

  19. Gene profiling of postnatal Mfrprd6 mutant eyes reveals differential accumulation of Prss56, visual cycle and phototransduction mRNAs.

    Directory of Open Access Journals (Sweden)

    Ramani Soundararajan

    Full Text Available Mutations in the membrane frizzled-related protein (MFRP/Mfrp gene, specifically expressed in the retinal pigment epithelium (RPE and ciliary body, cause nanophthalmia or posterior microphthalmia with retinitis pigmentosa in humans, and photoreceptor degeneration in mice. To better understand MFRP function, microarray analysis was performed on eyes of homozygous Mfrprd6 and C57BL/6J mice at postnatal days (P 0 and P14, prior to photoreceptor loss. Data analysis revealed no changes at P0 but significant differences in RPE and retina-specific transcripts at P14, suggesting a postnatal influence of the Mfrprd6 allele. A subset of these transcripts was validated by quantitative real-time PCR (qRT-PCR. In Mfrprd6 eyes, a significant 1.5- to 2.0-fold decrease was observed among transcripts of genes linked to retinal degeneration, including those involved in visual cycle (Rpe65, Lrat, Rgr, phototransduction (Pde6a, Guca1b, Rgs9, and photoreceptor disc morphogenesis (Rpgrip1 and Fscn2. Levels of RPE65 were significantly decreased by 2.0-fold. Transcripts of Prss56, a gene associated with angle-closure glaucoma, posterior microphthalmia and myopia, were increased in Mfrprd6 eyes by 17-fold. Validation by qRT-PCR indicated a 3.5-, 14- and 70-fold accumulation of Prss56 transcripts relative to controls at P7, P14 and P21, respectively. This trend was not observed in other RPE or photoreceptor mutant mouse models with similar disease progression, suggesting that Prss56 upregulation is a specific attribute of the disruption of Mfrp. Prss56 and Glul in situ hybridization directly identified Müller glia in the inner nuclear layer as the cell type expressing Prss56. In summary, the Mfrprd6 allele causes significant postnatal changes in transcript and protein levels in the retina and RPE. The link between Mfrp deficiency and Prss56 up-regulation, together with the genetic association of human MFRP or PRSS56 variants and ocular size, raises the possibility that

  20. Differences in relative amounts of two novel mutant HEXA transcripts in a juvenile TSD Druze patient

    Energy Technology Data Exchange (ETDEWEB)

    Drucker, L.; Navon, R. [Tel Aviv Univ. (Israel)]|[Sapir Medical Center, Kfar Sava (Israel)

    1994-09-01

    An Israeli-Druze patient with juvenile Tay-Sachs disease, born to first cousins, was found to be a compound heterozygote for two novel mutant HEXA alleles. SSCP analysis of the parents` genomic DNA revealed alterations in both exons 5 and 8. Direct sequencing showed a novel missense mutation T{sup 835}{r_arrow}C (Ser{sup 279}{r_arrow}Pro) in exon 8, of maternal origin. The mutant allele of paternal origin carried a novel double mutation in exon 5, (i) a C{sup 496} deletion, resulting in a frameshift and eventually a stop codon, (ii) a C{sup 496}{r_arrow}G transition which is a silent mutation. Both these latter mutations occur in the same codon. New restriction sites for ScrFI were introduced into the two mutant alleles, enabling rapid screening for their presence. In order to detect differences of the relative levels of the transcripts originating from the two mutant alleles, we applied allele-specific transcripts polymerase chain reaction (AST-PCR) to the RNA extractions prepared from the heterozygous parents (each carry a normal and mutant allele). In order to distinguish between the transcripts originating from the normal allele and those originating from each of the mutant alleles, the transcripts were digested by ScrFI. A severe depletion of the mRNA coded by the allele carrying the mutation in exon 5 was found. The phenomena corresponds with citations in the literature in cases of stop mutations. The allele carrying the transversion in exon 8, contrary to our expectations, also had a distinctly lower level of transcripts. The AST-PCR approach offers a molecular tool to study allele-specific gene expression in heterozygous individuals.

  1. Nanomolar oligomerization and selective co-aggregation of α-synuclein pathogenic mutants revealed by single-molecule fluorescence

    Science.gov (United States)

    Sierecki, Emma; Giles, Nichole; Bowden, Quill; Polinkovsky, Mark E.; Steinbeck, Janina; Arrioti, Nicholas; Rahman, Diya; Bhumkar, Akshay; Nicovich, Philip R.; Ross, Ian; Parton, Robert G.; Böcking, Till; Gambin, Yann

    2016-01-01

    Protein aggregation is a hallmark of many neurodegenerative diseases, notably Alzheimer’s and Parkinson’s disease. Parkinson’s disease is characterized by the presence of Lewy bodies, abnormal aggregates mainly composed of α-synuclein. Moreover, cases of familial Parkinson’s disease have been linked to mutations in α-synuclein. In this study, we compared the behavior of wild-type (WT) α-synuclein and five of its pathological mutants (A30P, E46K, H50Q, G51D and A53T). To this end, single-molecule fluorescence detection was coupled to cell-free protein expression to measure precisely the oligomerization of proteins without purification, denaturation or labelling steps. In these conditions, we could detect the formation of oligomeric and pre-fibrillar species at very short time scale and low micromolar concentrations. The pathogenic mutants surprisingly segregated into two classes: one group forming large aggregates and fibrils while the other tending to form mostly oligomers. Strikingly, co-expression experiments reveal that members from the different groups do not generally interact with each other, both at the fibril and monomer levels. Together, this data paints a completely different picture of α-synuclein aggregation, with two possible pathways leading to the development of fibrils. PMID:27892477

  2. The Arabidopsis nox mutant lacking carotene hydroxylase activity reveals a critical role for xanthophylls in photosystem I biogenesis.

    Science.gov (United States)

    Dall'Osto, Luca; Piques, Maria; Ronzani, Michela; Molesini, Barbara; Alboresi, Alessandro; Cazzaniga, Stefano; Bassi, Roberto

    2013-02-01

    Carotenes, and their oxygenated derivatives xanthophylls, are essential components of the photosynthetic apparatus. They contribute to the assembly of photosynthetic complexes and participate in light absorption and chloroplast photoprotection. Here, we studied the role of xanthophylls, as distinct from that of carotenes, by characterizing a no xanthophylls (nox) mutant of Arabidopsis thaliana, which was obtained by combining mutations targeting the four carotenoid hydroxylase genes. nox plants retained α- and β-carotenes but were devoid in xanthophylls. The phenotype included depletion of light-harvesting complex (LHC) subunits and impairment of nonphotochemical quenching, two effects consistent with the location of xanthophylls in photosystem II antenna, but also a decreased efficiency of photosynthetic electron transfer, photosensitivity, and lethality in soil. Biochemical analysis revealed that the nox mutant was specifically depleted in photosystem I function due to a severe deficiency in PsaA/B subunits. While the stationary level of psaA/B transcripts showed no major differences between genotypes, the stability of newly synthesized PsaA/B proteins was decreased and translation of psaA/B mRNA was impaired in nox with respect to wild-type plants. We conclude that xanthophylls, besides their role in photoprotection and LHC assembly, are also needed for photosystem I core translation and stability, thus making these compounds indispensable for autotrophic growth.

  3. SCREENING LOW FREQUENCY SNPS FROM GENOME WIDE ASSOCIATION STUDY REVEALS A NEW RISK ALLELE FOR PROGRESSION TO AIDS

    Science.gov (United States)

    Le Clerc, Sigrid; Coulonges, Cédric; Delaneau, Olivier; Van Manen, Danielle; Herbeck, Joshua T.; Limou, Sophie; An, Ping; Martinson, Jeremy J.; Spadoni, Jean-Louis; Therwath, Amu; Veldink, Jan H.; van den Berg, Leonard H.; Taing, Lieng; Labib, Taoufik; Mellak, Safa; Montes, Matthieu; Delfraissy, Jean-François; Schächter, François; Winkler, Cheryl; Froguel, Philippe; Mullins, James I.; Schuitemaker, Hanneke; Zagury, Jean-François

    2011-01-01

    Background Seven genome-wide association studies (GWAS) have been published in AIDS and only associations in the HLA region on chromosome 6 and CXCR6 have passed genome-wide significance. Methods We reanalyzed the data from three previously published GWAS, targeting specifically low frequency SNPs (minor allele frequency (MAF)<5%). Two groups composed of 365 slow progressors (SP) and 147 rapid progressors (RP) from Europe and the US were compared with a control group of 1394 seronegative individuals using Eigenstrat corrections. Results Of the 8584 SNPs with MAF<5% in cases and controls (Bonferroni threshold=5.8×10−6), four SNPs showed statistical evidence of association with the SP phenotype. The best result was for HCP5 rs2395029 (p=8.54×10−15, OR=3.41) in the HLA locus, in partial linkage disequilibrium with two additional chromosome 6 associations in C6orf48 (p=3.03×10−10, OR=2.9) and NOTCH4 (9.08×10−07, OR=2.32). The fourth association corresponded to rs2072255 located in RICH2 (p=3.30×10−06, OR=0.43) in chromosome 17. Using HCP5 rs2395029 as a covariate, the C6orf48 and NOTCH4 signals disappeared, but the RICH2 signal still remained significant. Conclusion Besides the already known chromosome 6 associations, the analysis of low frequency SNPs brought up a new association in the RICH2 gene. Interestingly, RICH2 interacts with BST-2 known to be a major restriction factor for HIV-1 infection. Our study has thus identified a new candidate gene for AIDS molecular etiology and confirms the interest of singling out low frequency SNPs in order to exploit GWAS data. PMID:21107268

  4. Allele-specific characterization of alanine: glyoxylate aminotransferase variants associated with primary hyperoxaluria.

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    Melissa D Lage

    Full Text Available Primary Hyperoxaluria Type 1 (PH1 is a rare autosomal recessive kidney stone disease caused by deficiency of the peroxisomal enzyme alanine: glyoxylate aminotransferase (AGT, which is involved in glyoxylate detoxification. Over 75 different missense mutations in AGT have been found associated with PH1. While some of the mutations have been found to affect enzyme activity, stability, and/or localization, approximately half of these mutations are completely uncharacterized. In this study, we sought to systematically characterize AGT missense mutations associated with PH1. To facilitate analysis, we used two high-throughput yeast-based assays: one that assesses AGT specific activity, and one that assesses protein stability. Approximately 30% of PH1-associated missense mutations are found in conjunction with a minor allele polymorphic variant, which can interact to elicit complex effects on protein stability and trafficking. To better understand this allele interaction, we functionally characterized each of 34 mutants on both the major (wild-type and minor allele backgrounds, identifying mutations that synergize with the minor allele. We classify these mutants into four distinct categories depending on activity/stability results in the different alleles. Twelve mutants were found to display reduced activity in combination with the minor allele, compared with the major allele background. When mapped on the AGT dimer structure, these mutants reveal localized regions of the protein that appear particularly sensitive to interactions with the minor allele variant. While the majority of the deleterious effects on activity in the minor allele can be attributed to synergistic interaction affecting protein stability, we identify one mutation, E274D, that appears to specifically affect activity when in combination with the minor allele.

  5. Stochastic modelling of shifts in allele frequencies reveals a strongly polygynous mating system in the re-introduced Asiatic wild ass.

    Science.gov (United States)

    Renan, Sharon; Greenbaum, Gili; Shahar, Naama; Templeton, Alan R; Bouskila, Amos; Bar-David, Shirli

    2015-04-01

    Small populations are prone to loss of genetic variation and hence to a reduction in their evolutionary potential. Therefore, studying the mating system of small populations and its potential effects on genetic drift and genetic diversity is of high importance for their viability assessments. The traditional method for studying genetic mating systems is paternity analysis. Yet, as small populations are often rare and elusive, the genetic data required for paternity analysis are frequently unavailable. The endangered Asiatic wild ass (Equus hemionus), like all equids, displays a behaviourally polygynous mating system; however, the level of polygyny has never been measured genetically in wild equids. Combining noninvasive genetic data with stochastic modelling of shifts in allele frequencies, we developed an alternative approach to paternity analysis for studying the genetic mating system of the re-introduced Asiatic wild ass in the Negev Desert, Israel. We compared the shifts in allele frequencies (as a measure of genetic drift) that have occurred in the wild ass population since re-introduction onset to simulated scenarios under different proportions of mating males. We revealed a strongly polygynous mating system in which less than 25% of all males participate in the mating process each generation. This strongly polygynous mating system and its potential effect on the re-introduced population's genetic diversity could have significant consequences for the long-term persistence of the population in the Negev. The stochastic modelling approach and the use of allele-frequency shifts can be further applied to systems that are affected by genetic drift and for which genetic data are limited. © 2015 John Wiley & Sons Ltd.

  6. Investigation of lethal and mutagenetic effects of UV-light on Salmonella currying wild and mutant alleles of lex A gene of Escherichia coli in the Salmonella genome

    International Nuclear Information System (INIS)

    Andreeva, I.V.; Tiganova, I.G.; Skavronskaya, A.G.

    1981-01-01

    Inheritance of LexA-gene of Escherichia coli- by Salmonella takes place during intergeneric trunsduction cross of Escherichia coli and Salmonella typhimurium. The presence of LexA-E. coli gene-did not eliminate earlier revealed peculiarity consisting in the absence of UV-induced mutagenesis in most of studied salmonollosis strains. So it is shown that the absence of UV mutagenesis in Salmonella does not result from mutation in LexA-gene. Inheritance of pKM101 by LexA-hybrid provides pronounced UV mutability and protective effect. Inheritance of this plasmid by LexA-hybrid did not result in the appearance of capability for UV-induced mutagenesis and improving UV resistance of bacteria. Thus the plasmids effect on repair and mutagenesis in Salmonella, the same as in E. coli, reveals in LexA-phenotype [ru

  7. Transcriptome profiling in engrailed-2 mutant mice reveals common molecular pathways associated with autism spectrum disorders.

    Science.gov (United States)

    Sgadò, Paola; Provenzano, Giovanni; Dassi, Erik; Adami, Valentina; Zunino, Giulia; Genovesi, Sacha; Casarosa, Simona; Bozzi, Yuri

    2013-12-19

    Transcriptome analysis has been used in autism spectrum disorder (ASD) to unravel common pathogenic pathways based on the assumption that distinct rare genetic variants or epigenetic modifications affect common biological pathways. To unravel recurrent ASD-related neuropathological mechanisms, we took advantage of the En2-/- mouse model and performed transcriptome profiling on cerebellar and hippocampal adult tissues. Cerebellar and hippocampal tissue samples from three En2-/- and wild type (WT) littermate mice were assessed for differential gene expression using microarray hybridization followed by RankProd analysis. To identify functional categories overrepresented in the differentially expressed genes, we used integrated gene-network analysis, gene ontology enrichment and mouse phenotype ontology analysis. Furthermore, we performed direct enrichment analysis of ASD-associated genes from the SFARI repository in our differentially expressed genes. Given the limited number of animals used in the study, we used permissive criteria and identified 842 differentially expressed genes in En2-/- cerebellum and 862 in the En2-/- hippocampus. Our functional analysis revealed that the molecular signature of En2-/- cerebellum and hippocampus shares convergent pathological pathways with ASD, including abnormal synaptic transmission, altered developmental processes and increased immune response. Furthermore, when directly compared to the repository of the SFARI database, our differentially expressed genes in the hippocampus showed enrichment of ASD-associated genes significantly higher than previously reported. qPCR was performed for representative genes to confirm relative transcript levels compared to those detected in microarrays. Despite the limited number of animals used in the study, our bioinformatic analysis indicates the En2-/- mouse is a valuable tool for investigating molecular alterations related to ASD.

  8. Genetic analysis of Chinese families reveals a novel truncation allele of the retinitis pigmentosa GTPase regulator gene

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    Fang Hu

    2014-10-01

    Full Text Available AIM: To make comprehensive molecular diagnosis for retinitis pigmentosa (RP patients in a consanguineous Han Chinese family using next generation sequencing based Capture-NGS screen technology. METHODS: A five-generation Han Chinese family diagnosed as non-syndromic X-linked recessive RP (XLRP was recruited, including four affected males, four obligate female carriers and eleven unaffected family members. Capture-NGS was performed using a custom designed capture panel covers 163 known retinal disease genes including 47 RP genes, followed by the validation of detected mutation using Sanger sequencing in all recruited family members. RESULTS: Capture-NGS in one affected 47-year-old male reveals a novel mutation, c.2417_2418insG:p.E806fs, in exon ORF15 of RP GTPase regulator (RPGR gene results in a frameshift change that results in a premature stop codon and a truncated protein product. The mutation was further validated in three of four affected males and two of four female carriers but not in the other unaffected family members. CONCLUSION: We have identified a novel mutation, c.2417_2418insG:p.E806fs, in a Han Chinese family with XLRP. Our findings expand the mutation spectrum of RPGR and the phenotypic spectrum of XLRP in Han Chinese families, and confirms Capture-NGS could be an effective and economic approach for the comprehensive molecular diagnosis of RP.

  9. Temperature sensitive riboflavin mutants of Penicillium vermiculatum Dangeard

    International Nuclear Information System (INIS)

    Mitra, J.; Chaudhari, K.L.

    1974-01-01

    Two temperature sensitive UV induced riboflavin mutants rib 1 and rib 6 have been physiologically and genetically characterized. The two mutants behave differently with regard to their temperature sensitivity. The rib 1 mutant exhibits a leaky growth in minimal medium between 15 0 C and 30 0 C but grows well when the medium is supplemented with riboflavin. At 35 0 C the growth response of the mutant is at its max. and at 40 0 C and below 15 0 C it ceases to grow. The rib 6 mutant which is red brown in colour shows wild type character at temp. below 25 0 C in minimal medium but requires riboflavin at 30 0 C and above. Heterokaryotic analysis revealed the nonallelic nature of the two temperature mutants. Genetic tests of allelic relationship between riboflavin markers by crossing were also done. (author)

  10. Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis.

    Science.gov (United States)

    Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

    2015-09-01

    Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. © 2015 American Society of Plant Biologists. All Rights Reserved.

  11. GWAS of follicular lymphoma reveals allelic heterogeneity at 6p21.32 and suggests shared genetic susceptibility with diffuse large B-cell lymphoma.

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    Karin E Smedby

    2011-04-01

    Full Text Available Non-Hodgkin lymphoma (NHL represents a diverse group of hematological malignancies, of which follicular lymphoma (FL is a prevalent subtype. A previous genome-wide association study has established a marker, rs10484561 in the human leukocyte antigen (HLA class II region on 6p21.32 associated with increased FL risk. Here, in a three-stage genome-wide association study, starting with a genome-wide scan of 379 FL cases and 791 controls followed by validation in 1,049 cases and 5,790 controls, we identified a second independent FL-associated locus on 6p21.32, rs2647012 (OR(combined  = 0.64, P(combined  = 2 × 10(-21 located 962 bp away from rs10484561 (r(2<0.1 in controls. After mutual adjustment, the associations at the two SNPs remained genome-wide significant (rs2647012:OR(adjusted  = 0.70, P(adjusted  =  4 × 10(-12; rs10484561:OR(adjusted  = 1.64, P(adjusted  = 5 × 10(-15. Haplotype and coalescence analyses indicated that rs2647012 arose on an evolutionarily distinct haplotype from that of rs10484561 and tags a novel allele with an opposite (protective effect on FL risk. Moreover, in a follow-up analysis of the top 6 FL-associated SNPs in 4,449 cases of other NHL subtypes, rs10484561 was associated with risk of diffuse large B-cell lymphoma (OR(combined  = 1.36, P(combined  =  1.4 × 10(-7. Our results reveal the presence of allelic heterogeneity within the HLA class II region influencing FL susceptibility and indicate a possible shared genetic etiology with diffuse large B-cell lymphoma. These findings suggest that the HLA class II region plays a complex yet important role in NHL.

  12. Transcriptome and proteomic analyses reveal multiple differences associated with chloroplast development in the spaceflight-induced wheat albino mutant mta.

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    Kui Shi

    Full Text Available Chloroplast development is an integral part of plant survival and growth, and occurs in parallel with chlorophyll biosynthesis. However, little is known about the mechanisms underlying chloroplast development in hexaploid wheat. Here, we obtained a spaceflight-induced wheat albino mutant mta. Chloroplast ultra-structural observation showed that chloroplasts of mta exhibit abnormal morphology and distribution compared to wild type. Photosynthetic pigments content was also significantly decreased in mta. Transcriptome and chloroplast proteome profiling of mta and wild type were done to identify differentially expressed genes (DEGs and proteins (DEPs, respectively. In total 4,588 DEGs including 1,980 up- and 2,608 down-regulated, and 48 chloroplast DEPs including 15 up- and 33 down-regulated were identified in mta. Classification of DEGs revealed that most were involved in chloroplast development, chlorophyll biosynthesis, or photosynthesis. Besides, transcription factors such as PIF3, GLK and MYB which might participate in those pathways were also identified. The correlation analysis between DEGs and DEPs revealed that the transcript-to-protein in abundance was functioned into photosynthesis and chloroplast relevant groups. Real time qPCR analysis validated that the expression level of genes encoding photosynthetic proteins was significantly decreased in mta. Together, our results suggest that the molecular mechanism for albino leaf color formation in mta is a thoroughly regulated and complicated process. The combined analysis of transcriptome and proteome afford comprehensive information for further research on chloroplast development mechanism in wheat. And spaceflight provides a potential means for mutagenesis in crop breeding.

  13. Longevity Genes Revealed by Integrative Analysis of Isoform-Specific daf-16/FoxO Mutants of Caenorhabditis elegans.

    Science.gov (United States)

    Chen, Albert Tzong-Yang; Guo, Chunfang; Itani, Omar A; Budaitis, Breane G; Williams, Travis W; Hopkins, Christopher E; McEachin, Richard C; Pande, Manjusha; Grant, Ana R; Yoshina, Sawako; Mitani, Shohei; Hu, Patrick J

    2015-10-01

    FoxO transcription factors promote longevity across taxa. How they do so is poorly understood. In the nematode Caenorhabditis elegans, the A- and F-isoforms of the FoxO transcription factor DAF-16 extend life span in the context of reduced DAF-2 insulin-like growth factor receptor (IGFR) signaling. To elucidate the mechanistic basis for DAF-16/FoxO-dependent life span extension, we performed an integrative analysis of isoform-specific daf-16/FoxO mutants. In contrast to previous studies suggesting that DAF-16F plays a more prominent role in life span control than DAF-16A, isoform-specific daf-16/FoxO mutant phenotypes and whole transcriptome profiling revealed a predominant role for DAF-16A over DAF-16F in life span control, stress resistance, and target gene regulation. Integration of these datasets enabled the prioritization of a subset of 92 DAF-16/FoxO target genes for functional interrogation. Among 29 genes tested, two DAF-16A-specific target genes significantly influenced longevity. A loss-of-function mutation in the conserved gene gst-20, which is induced by DAF-16A, reduced life span extension in the context of daf-2/IGFR RNAi without influencing longevity in animals subjected to control RNAi. Therefore, gst-20 promotes DAF-16/FoxO-dependent longevity. Conversely, a loss-of-function mutation in srr-4, a gene encoding a seven-transmembrane-domain receptor family member that is repressed by DAF-16A, extended life span in control animals, indicating that DAF-16/FoxO may extend life span at least in part by reducing srr-4 expression. Our discovery of new longevity genes underscores the efficacy of our integrative strategy while providing a general framework for identifying specific downstream gene regulatory events that contribute substantially to transcription factor functions. As FoxO transcription factors have conserved functions in promoting longevity and may be dysregulated in aging-related diseases, these findings promise to illuminate fundamental

  14. Sequence-Based Genotyping of Expressed Swine Leukocyte Antigen Class I Alleles by Next-Generation Sequencing Reveal Novel Swine Leukocyte Antigen Class I Haplotypes and Alleles in Belgian, Danish, and Kenyan Fattening Pigs and Göttingen Minipigs

    DEFF Research Database (Denmark)

    Sørensen, Maria Rathmann; Ilsøe, Mette; Strube, Mikael Lenz

    2017-01-01

    for the prediction of epitope binding in pigs. The low number of known SLA class I alleles and the limited knowledge of their prevalence in different pig breeds emphasizes the need for efficient SLA typing methods. This study utilizes an SLA class I-typing method based on next-generation sequencing of barcoded PCR...

  15. Integrative proteomics, genomics, and translational immunology approaches reveal mutated forms of Proteolipid Protein 1 (PLP1) and mutant-specific immune response in multiple sclerosis.

    Science.gov (United States)

    Qendro, Veneta; Bugos, Grace A; Lundgren, Debbie H; Glynn, John; Han, May H; Han, David K

    2017-03-01

    In order to gain mechanistic insights into multiple sclerosis (MS) pathogenesis, we utilized a multi-dimensional approach to test the hypothesis that mutations in myelin proteins lead to immune activation and central nervous system autoimmunity in MS. Mass spectrometry-based proteomic analysis of human MS brain lesions revealed seven unique mutations of PLP1; a key myelin protein that is known to be destroyed in MS. Surprisingly, in-depth genomic analysis of two MS patients at the genomic DNA and mRNA confirmed mutated PLP1 in RNA, but not in the genomic DNA. Quantification of wild type and mutant PLP RNA levels by qPCR further validated the presence of mutant PLP RNA in the MS patients. To seek evidence linking mutations in abundant myelin proteins and immune-mediated destruction of myelin, specific immune response against mutant PLP1 in MS patients was examined. Thus, we have designed paired, wild type and mutant peptide microarrays, and examined antibody response to multiple mutated PLP1 in sera from MS patients. Consistent with the idea of different patients exhibiting unique mutation profiles, we found that 13 out of 20 MS patients showed antibody responses against specific but not against all the mutant-PLP1 peptides. Interestingly, we found mutant PLP-directed antibody response against specific mutant peptides in the sera of pre-MS controls. The results from integrative proteomic, genomic, and immune analyses reveal a possible mechanism of mutation-driven pathogenesis in human MS. The study also highlights the need for integrative genomic and proteomic analyses for uncovering pathogenic mechanisms of human diseases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Revealing differences in metabolic flux distributions between a mutant strain and its parent strain Gluconacetobacter xylinus CGMCC 2955.

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    Cheng Zhong

    Full Text Available A better understanding of metabolic fluxes is important for manipulating microbial metabolism toward desired end products, or away from undesirable by-products. A mutant strain, Gluconacetobacter xylinus AX2-16, was obtained by combined chemical mutation of the parent strain (G. xylinus CGMCC 2955 using DEC (diethyl sulfate and LiCl. The highest bacterial cellulose production for this mutant was obtained at about 11.75 g/L, which was an increase of 62% compared with that by the parent strain. In contrast, gluconic acid (the main byproduct concentration was only 5.71 g/L for mutant strain, which was 55.7% lower than that of parent strain. Metabolic flux analysis indicated that 40.1% of the carbon source was transformed to bacterial cellulose in mutant strain, compared with 24.2% for parent strain. Only 32.7% and 4.0% of the carbon source were converted into gluconic acid and acetic acid in mutant strain, compared with 58.5% and 9.5% of that in parent strain. In addition, a higher flux of tricarboxylic acid (TCA cycle was obtained in mutant strain (57.0% compared with parent strain (17.0%. It was also indicated from the flux analysis that more ATP was produced in mutant strain from pentose phosphate pathway (PPP and TCA cycle. The enzymatic activity of succinate dehydrogenase (SDH, which is one of the key enzymes in TCA cycle, was 1.65-fold higher in mutant strain than that in parent strain at the end of culture. It was further validated by the measurement of ATPase that 3.53-6.41 fold higher enzymatic activity was obtained from mutant strain compared with parent strain.

  17. Analysis of HLA class II haplotypes in the Cayapa indians of ecuador: A novel DRBI allele reveals evidence for convergent evolution and balancing selection at position 86

    Energy Technology Data Exchange (ETDEWEB)

    Titus-Trachtenberg, E.A.; Erlich, H. (Roche Molecular Systems, Alameda, CA (United States)); Rickards, O.; De Stefano, G.F. (Universita di Roma, Rome (Italy))

    1994-07-01

    PCR amplification, oligonucleotide probe typing, and sequencing were used to analyze the HLA class II loci (DRB1, DQA1, DAB1, and DPB1) of an isolated South Amerindian tribe. Here the authors report HLA class II variation, including the identification of a new DRB1 allele, several novel DR/DQ haplotypes, and an unusual distribution of DPB1 alleles, among the Cayapa Indians (N=100) of Ecuador. A general reduction of HLA class II allelic variation in the Cayapa is consistent with a population bottleneck during the colonization of the Americas. The new Cayapa DRB1 allele, DRB1[sup *]08042, which arose by a G[yields]T point mutation in the parental DRB1[sup *]0802, contains a novel Val codon (GTT) at position 86. The generation of DRB1[sup *]08042 (Val-86) from DRB1[sup *]0802 (Gly-86) in the Cayapa, by a different mechanism than the (GT[yields]TG) change in the creation of DRB1[sub *]08041 (Val-86) from DRB1[sup *]0802 in Africa, implicates selection in the convergent evolution of position 86 DR[beta] variants. The DRB1[sup *]08042 allele has not been found in >1,800 Amerindian haplotypes and thus presumably arose after the Cayapa separated from other South American Amerindians. Selection pressure for increased haplotype diversity can be inferred in the generation and maintenance of three new DRB1[sup *]08042 haplotypes and several novel DR/DQ haplotypes in this population. The DPB1 allelic distribution in the Cayapa is also extraordinary, with two alleles, DPB1[sup *]1401, a very rare allele in North American Amerindian populations, and DPB1[sup *]0402, the most common Amerindian DPB1 allele, constituting 89% of the Cayapa DPB1. These data are consistent with the postulated rapid rate of evolution as noted for the class I HLA-B locus of other South American Indians. 34 refs., 2 figs., 2 tabs.

  18. Genomic data reveal Toxoplasma gondii differentiation mutants are also impaired with respect to switching into a novel extracellular tachyzoite state.

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    Pamela J Lescault

    2010-12-01

    Full Text Available Toxoplasma gondii pathogenesis includes the invasion of host cells by extracellular parasites, replication of intracellular tachyzoites, and differentiation to a latent bradyzoite stage. We present the analysis of seven novel T. gondii insertional mutants that do not undergo normal differentiation to bradyzoites. Microarray quantification of the variation in genome-wide RNA levels for each parasite line and times after induction allowed us to describe states in the normal differentiation process, to analyze mutant lines in the context of these states, and to identify genes that may have roles in initiating the transition from tachyzoite to bradyzoite. Gene expression patterns in wild-type parasites undergoing differentiation suggest a novel extracellular state within the tachyzoite stage. All mutant lines exhibit aberrant regulation of bradyzoite gene expression and notably some of the mutant lines appear to exhibit high proportions of the intracellular tachyzoite state regardless of whether they are intracellular or extracellular. In addition to the genes identified by the insertional mutagenesis screen, mixture model analysis allowed us to identify a small number of genes, in mutants, for which expression patterns could not be accounted for using the three parasite states--genes that may play a mechanistic role in switching from the tachyzoite to bradyzoite stage.

  19. The Arabidopsis cax1 mutant exhibits impaired ion homeostasis, development, and hormonal responses and reveals interplay among vacuolar transporters.

    Science.gov (United States)

    Cheng, Ning-Hui; Pittman, Jon K; Barkla, Bronwyn J; Shigaki, Toshiro; Hirschi, Kendal D

    2003-02-01

    The Arabidopsis Ca(2+)/H(+) transporter CAX1 (Cation Exchanger1) may be an important regulator of intracellular Ca(2+) levels. Here, we describe the preliminary localization of CAX1 to the tonoplast and the molecular and biochemical characterization of cax1 mutants. We show that these mutants exhibit a 50% reduction in tonoplast Ca(2+)/H(+) antiport activity, a 40% reduction in tonoplast V-type H(+)-translocating ATPase activity, a 36% increase in tonoplast Ca(2+)-ATPase activity, and increased expression of the putative vacuolar Ca(2+)/H(+) antiporters CAX3 and CAX4. Enhanced growth was displayed by the cax1 lines under Mn(2+) and Mg(2+) stress conditions. The mutants exhibited altered plant development, perturbed hormone sensitivities, and altered expression of an auxin-regulated promoter-reporter gene fusion. We propose that CAX1 regulates myriad plant processes and discuss the observed phenotypes with regard to the compensatory alterations in other transporters.

  20. The Arabidopsis cax1 Mutant Exhibits Impaired Ion Homeostasis, Development, and Hormonal Responses and Reveals Interplay among Vacuolar Transporters

    Science.gov (United States)

    Cheng, Ning-Hui; Pittman, Jon K.; Barkla, Bronwyn J.; Shigaki, Toshiro; Hirschi, Kendal D.

    2003-01-01

    The Arabidopsis Ca2+/H+ transporter CAX1 (Cation Exchanger1) may be an important regulator of intracellular Ca2+ levels. Here, we describe the preliminary localization of CAX1 to the tonoplast and the molecular and biochemical characterization of cax1 mutants. We show that these mutants exhibit a 50% reduction in tonoplast Ca2+/H+ antiport activity, a 40% reduction in tonoplast V-type H+-translocating ATPase activity, a 36% increase in tonoplast Ca2+-ATPase activity, and increased expression of the putative vacuolar Ca2+/H+ antiporters CAX3 and CAX4. Enhanced growth was displayed by the cax1 lines under Mn2+ and Mg2+ stress conditions. The mutants exhibited altered plant development, perturbed hormone sensitivities, and altered expression of an auxin-regulated promoter-reporter gene fusion. We propose that CAX1 regulates myriad plant processes and discuss the observed phenotypes with regard to the compensatory alterations in other transporters. PMID:12566577

  1. Dissection of the complex phenotype in cuticular mutants of Arabidopsis reveals a role of SERRATE as a mediator.

    Directory of Open Access Journals (Sweden)

    Derry Voisin

    2009-10-01

    Full Text Available Mutations in LACERATA (LCR, FIDDLEHEAD (FDH, and BODYGUARD (BDG cause a complex developmental syndrome that is consistent with an important role for these Arabidopsis genes in cuticle biogenesis. The genesis of their pleiotropic phenotypes is, however, poorly understood. We provide evidence that neither distorted depositions of cutin, nor deficiencies in the chemical composition of cuticular lipids, account for these features, instead suggesting that the mutants alleviate the functional disorder of the cuticle by reinforcing their defenses. To better understand how plants adapt to these mutations, we performed a genome-wide gene expression analysis. We found that apparent compensatory transcriptional responses in these mutants involve the induction of wax, cutin, cell wall, and defense genes. To gain greater insight into the mechanism by which cuticular mutations trigger this response in the plants, we performed an overlap meta-analysis, which is termed MASTA (MicroArray overlap Search Tool and Analysis, of differentially expressed genes. This suggested that different cell integrity pathways are recruited in cesA cellulose synthase and cuticular mutants. Using MASTA for an in silico suppressor/enhancer screen, we identified SERRATE (SE, which encodes a protein of RNA-processing multi-protein complexes, as a likely enhancer. In confirmation of this notion, the se lcr and se bdg double mutants eradicate severe leaf deformations as well as the organ fusions that are typical of lcr and bdg and other cuticular mutants. Also, lcr does not confer resistance to Botrytis cinerea in a se mutant background. We propose that there is a role for SERRATE-mediated RNA signaling in the cuticle integrity pathway.

  2. Analysis of triclosan-selected Salmonella enterica mutants of eight serovars revealed increased aminoglycoside susceptibility and reduced growth rates.

    Directory of Open Access Journals (Sweden)

    Ulrike Rensch

    Full Text Available The biocide triclosan (TRC is used in a wide range of household, personal care, veterinary, industrial and medical products to control microbial growth. This extended use raises concerns about a possible association between the application of triclosan and the development of antibiotic resistance. In the present study we determined triclosan mutant prevention concentrations (MPC for Salmonella enterica isolates of eight serovars and investigated selected mutants for their mechanisms mediating decreased susceptibility to triclosan. MPCTRC values were 8-64-fold higher than MIC values and ranged between 1-16 µg/ml. The frequencies at which mutants were selected varied between 1.3 x 10(-10-9.9 x 10(-11. Even if MIC values of mutants decreased by 3-7 dilution steps in the presence of the efflux pump inhibitor Phe-Arg-β-naphtylamide, only minor changes were observed in the expression of genes encoding efflux components or regulators, indicating that neither the major multidrug efflux pump AcrAB-TolC nor AcrEF are up-regulated in triclosan-selected mutants. Nucleotide sequence comparisons confirmed the absence of alterations in the regulatory regions acrRA, soxRS, marORAB, acrSE and ramRA of selected mutants. Single bp and deduced Gly93→Val amino acid exchanges were present in fabI, the target gene of triclosan, starting from a concentration of 1 µg/ml TRC used for MPC determinations. The fabI genes were up to 12.4-fold up-regulated. Complementation experiments confirmed the contribution of Gly93→Val exchanges and fabI overexpression to decreased triclosan susceptibility. MIC values of mutants compared to parent strains were even equal or resulted in a more susceptible phenotype (1-2 dilution steps for the aminoglycoside antibiotics kanamycin and gentamicin as well as for the biocide chlorhexidine. Growth rates of selected mutants were significantly lower and hence, might partly explain the rare occurrence of Salmonella field isolates exhibiting

  3. The deoxyhypusine synthase mutant dys1-1 reveals the association of eIF5A and Asc1 with cell wall integrity.

    Directory of Open Access Journals (Sweden)

    Fabio Carrilho Galvão

    Full Text Available The putative eukaryotic translation initiation factor 5A (eIF5A is a highly conserved protein among archaea and eukaryotes that has recently been implicated in the elongation step of translation. eIF5A undergoes an essential and conserved posttranslational modification at a specific lysine to generate the residue hypusine. The enzymes deoxyhypusine synthase (Dys1 and deoxyhypusine hydroxylase (Lia1 catalyze this two-step modification process. Although several Saccharomyces cerevisiae eIF5A mutants have importantly contributed to the study of eIF5A function, no conditional mutant of Dys1 has been described so far. In this study, we generated and characterized the dys1-1 mutant, which showed a strong depletion of mutated Dys1 protein, resulting in more than 2-fold decrease in hypusine levels relative to the wild type. The dys1-1 mutant demonstrated a defect in total protein synthesis, a defect in polysome profile indicative of a translation elongation defect and a reduced association of eIF5A with polysomes. The growth phenotype of dys1-1 mutant is severe, growing only in the presence of 1 M sorbitol, an osmotic stabilizer. Although this phenotype is characteristic of Pkc1 cell wall integrity mutants, the sorbitol requirement from dys1-1 is not associated with cell lysis. We observed that the dys1-1 genetically interacts with the sole yeast protein kinase C (Pkc1 and Asc1, a component of the 40S ribosomal subunit. The dys1-1 mutant was synthetically lethal in combination with asc1Δ and overexpression of TIF51A (eIF5A or DYS1 is toxic for an asc1Δ strain. Moreover, eIF5A is more associated with translating ribosomes in the absence of Asc1 in the cell. Finally, analysis of the sensitivity to cell wall-perturbing compounds revealed a more similar behavior of the dys1-1 and asc1Δ mutants in comparison with the pkc1Δ mutant. These data suggest a correlated role for eIF5A and Asc1 in coordinating the translational control of a subset of m

  4. Serrated leaf mutant in mungbean (Vigna radiata (L) Wilczek)

    International Nuclear Information System (INIS)

    Malik, I.A.; Ghulam, Sarwar; Yousaf, Ali; Saleem, M.

    1988-01-01

    Dry dormant seeds of mungbean (Vigna radiata (L) Wilczek) were treated with gamma rays (15, 30 and 60 kR). The serrated leaf mutation was noticed in M 2 of cultivar Pak 32 treated with 60 kR. Cf 14 plants, 3 showed the altered leaf structure and the others were normal. The feature of this mutant was the deep serration of leaflet margins. The mutant had large thick leaflets with prominent venation. The mutant bred true in the M 3 and successive generation. Details of the morphological characteristics of the mutant are presented. The mutant exhibited slower growth particularly during the early stages of development, flowered later and attained shorter height. There was an increase in the number of pods, in seed weight and in seed protein content, but number of seed per pod was considerably reduced. The seed coat colour showed a change from green to yellowish green. In the mutant's flowers the stamina were placed much below the stigma level and the stigma sometimes protruded the corolla. Outcrossing of 4% recorded in some of the mutant lines revealed a reduced cleistogamy. The low number of seeds per pod in the mutant could be due to reduced pollen fertility. The mutant behaved as monogenic recessive. The symbols SL/sl are proposed for this allelic pair. The mutant may have use as a green manure crop because of its large foliage and for the breeders as a genetic marker

  5. Gene expression profile analysis of Ligon lintless-1 (Li1) mutant reveals important genes and pathways in cotton leaf and fiber development.

    Science.gov (United States)

    Ding, Mingquan; Jiang, Yurong; Cao, Yuefen; Lin, Lifeng; He, Shae; Zhou, Wei; Rong, Junkang

    2014-02-10

    Ligon lintless-1 (Li1) is a monogenic dominant mutant of Gossypium hirsutum (upland cotton) with a phenotype of impaired vegetative growth and short lint fibers. Despite years of research involving genetic mapping and gene expression profile analysis of Li1 mutant ovule tissues, the gene remains uncloned and the underlying pathway of cotton fiber elongation is still unclear. In this study, we report the whole genome-level deep-sequencing analysis of leaf tissues of the Li1 mutant. Differentially expressed genes in leaf tissues of mutant versus wild-type (WT) plants are identified, and the underlying pathways and potential genes that control leaf and fiber development are inferred. The results show that transcription factors AS2, YABBY5, and KANDI-like are significantly differentially expressed in mutant tissues compared with WT ones. Interestingly, several fiber development-related genes are found in the downregulated gene list of the mutant leaf transcriptome. These genes include heat shock protein family, cytoskeleton arrangement, cell wall synthesis, energy, H2O2 metabolism-related genes, and WRKY transcription factors. This finding suggests that the genes are involved in leaf morphology determination and fiber elongation. The expression data are also compared with the previously published microarray data of Li1 ovule tissues. Comparative analysis of the ovule transcriptomes of Li1 and WT reveals that a number of pathways important for fiber elongation are enriched in the downregulated gene list at different fiber development stages (0, 6, 9, 12, 15, 18dpa). Differentially expressed genes identified in both leaf and fiber samples are aligned with cotton whole genome sequences and combined with the genetic fine mapping results to identify a list of candidate genes for Li1. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Protein expression profiling of the drosophila fragile X mutant brain reveals up-regulation of monoamine synthesis.

    Science.gov (United States)

    Zhang, Yong Q; Friedman, David B; Wang, Zhe; Woodruff, Elvin; Pan, Luyuan; O'donnell, Janis; Broadie, Kendal

    2005-03-01

    Fragile X syndrome is the most common form of inherited mental retardation, associated with both cognitive and behavioral anomalies. The disease is caused by silencing of the fragile X mental retardation 1 (fmr1) gene, which encodes the mRNA-binding, translational regulator FMRP. Previously we established a disease model through mutation of Drosophila fmr1 (dfmr1) and showed that loss of dFMRP causes defects in neuronal structure, function, and behavioral output similar to the human disease state. To uncover molecular targets of dFMRP in the brain, we use here a proteomic approach involving two-dimensional difference gel electrophoresis analyses followed by mass spectrometry identification of proteins with significantly altered expression in dfmr1 null mutants. We then focus on two misregulated enzymes, phenylalanine hydroxylase (Henna) and GTP cyclohydrolase (Punch), both of which mediate in concert the synthetic pathways of two key monoamine neuromodulators, dopamine and serotonin. Brain enzymatic assays show a nearly 2-fold elevation of Punch activity in dfmr1 null mutants. Consistently brain neurochemical assays show that both dopamine and serotonin are significantly increased in dfmr1 null mutants. At a cellular level, dfmr1 null mutant neurons display a highly significant elevation of the dense core vesicles that package these monoamine neuromodulators for secretion. Taken together, these data indicate that dFMRP normally down-regulates the monoamine pathway, which is consequently up-regulated in the mutant condition. Elevated brain levels of dopamine and serotonin provide a plausible mechanistic explanation for aspects of cognitive and behavioral deficits in human patients.

  7. Transcriptomic and proteomic approach to identify differentially expressed genes and proteins in Arabidopsis thaliana mutants lacking chloroplastic 1 and cytosolic FBPases reveals several levels of metabolic regulation.

    Science.gov (United States)

    Soto-Suárez, Mauricio; Serrato, Antonio J; Rojas-González, José A; Bautista, Rocío; Sahrawy, Mariam

    2016-12-01

    During the photosynthesis, two isoforms of the fructose-1,6-bisphosphatase (FBPase), the chloroplastidial (cFBP1) and the cytosolic (cyFBP), catalyse the first irreversible step during the conversion of triose phosphates (TP) to starch or sucrose, respectively. Deficiency in cyFBP and cFBP1 isoforms provokes an imbalance of the starch/sucrose ratio, causing a dramatic effect on plant development when the plastidial enzyme is lacking. We study the correlation between the transcriptome and proteome profile in rosettes and roots when cFBP1 or cyFBP genes are disrupted in Arabidopsis thaliana knock-out mutants. By using a 70-mer oligonucleotide microarray representing the genome of Arabidopsis we were able to identify 1067 and 1243 genes whose expressions are altered in the rosettes and roots of the cfbp1 mutant respectively; whilst in rosettes and roots of cyfbp mutant 1068 and 1079 genes are being up- or down-regulated respectively. Quantitative real-time PCR validated 100% of a set of 14 selected genes differentially expressed according to our microarray analysis. Two-dimensional (2-D) gel electrophoresis-based proteomic analysis revealed quantitative differences in 36 and 26 proteins regulated in rosettes and roots of cfbp1, respectively, whereas the 18 and 48 others were regulated in rosettes and roots of cyfbp mutant, respectively. The genes differentially expressed and the proteins more or less abundant revealed changes in protein metabolism, RNA regulation, cell signalling and organization, carbon metabolism, redox regulation, and transport together with biotic and abiotic stress. Notably, a significant set (25%) of the proteins identified were also found to be regulated at a transcriptional level. This transcriptomic and proteomic analysis is the first comprehensive and comparative study of the gene/protein re-adjustment that occurs in photosynthetic and non-photosynthetic organs of Arabidopsis mutants lacking FBPase isoforms.

  8. Automated analysis of high-throughput B-cell sequencing data reveals a high frequency of novel immunoglobulin V gene segment alleles.

    Science.gov (United States)

    Gadala-Maria, Daniel; Yaari, Gur; Uduman, Mohamed; Kleinstein, Steven H

    2015-02-24

    Individual variation in germline and expressed B-cell immunoglobulin (Ig) repertoires has been associated with aging, disease susceptibility, and differential response to infection and vaccination. Repertoire properties can now be studied at large-scale through next-generation sequencing of rearranged Ig genes. Accurate analysis of these repertoire-sequencing (Rep-Seq) data requires identifying the germline variable (V), diversity (D), and joining (J) gene segments used by each Ig sequence. Current V(D)J assignment methods work by aligning sequences to a database of known germline V(D)J segment alleles. However, existing databases are likely to be incomplete and novel polymorphisms are hard to differentiate from the frequent occurrence of somatic hypermutations in Ig sequences. Here we develop a Tool for Ig Genotype Elucidation via Rep-Seq (TIgGER). TIgGER analyzes mutation patterns in Rep-Seq data to identify novel V segment alleles, and also constructs a personalized germline database containing the specific set of alleles carried by a subject. This information is then used to improve the initial V segment assignments from existing tools, like IMGT/HighV-QUEST. The application of TIgGER to Rep-Seq data from seven subjects identified 11 novel V segment alleles, including at least one in every subject examined. These novel alleles constituted 13% of the total number of unique alleles in these subjects, and impacted 3% of V(D)J segment assignments. These results reinforce the highly polymorphic nature of human Ig V genes, and suggest that many novel alleles remain to be discovered. The integration of TIgGER into Rep-Seq processing pipelines will increase the accuracy of V segment assignments, thus improving B-cell repertoire analyses.

  9. Sequence analysis of two alleles reveals that intra-and intergenic recombination played a role in the evolution of the radish fertility restorer (Rfo

    Directory of Open Access Journals (Sweden)

    Budar Françoise

    2010-02-01

    Full Text Available Abstract Background Land plant genomes contain multiple members of a eukaryote-specific gene family encoding proteins with pentatricopeptide repeat (PPR motifs. Some PPR proteins were shown to participate in post-transcriptional events involved in organellar gene expression, and this type of function is now thought to be their main biological role. Among PPR genes, restorers of fertility (Rf of cytoplasmic male sterility systems constitute a peculiar subgroup that is thought to evolve in response to the presence of mitochondrial sterility-inducing genes. Rf genes encoding PPR proteins are associated with very close relatives on complex loci. Results We sequenced a non-restoring allele (L7rfo of the Rfo radish locus whose restoring allele (D81Rfo was previously described, and compared the two alleles and their PPR genes. We identified a ca 13 kb long fragment, likely originating from another part of the radish genome, inserted into the L7rfo sequence. The L7rfo allele carries two genes (PPR-1 and PPR-2 closely related to the three previously described PPR genes of the restorer D81Rfo allele (PPR-A, PPR-B, and PPR-C. Our results indicate that alleles of the Rfo locus have experienced complex evolutionary events, including recombination and insertion of extra-locus sequences, since they diverged. Our analyses strongly suggest that present coding sequences of Rfo PPR genes result from intragenic recombination. We found that the 10 C-terminal PPR repeats in Rfo PPR gene encoded proteins result from the tandem duplication of a 5 PPR repeat block. Conclusions The Rfo locus appears to experience more complex evolution than its flanking sequences. The Rfo locus and PPR genes therein are likely to evolve as a result of intergenic and intragenic recombination. It is therefore not possible to determine which genes on the two alleles are direct orthologs. Our observations recall some previously reported data on pathogen resistance complex loci.

  10. Investigation of intercellular salicylic acid accumulation during compatible and incompatible Arabidopsis-pseudomonas syringae interactions using a fast neutron-generated mutant allele of EDS5 identified by genetic mapping and whole-genome sequencing.

    Directory of Open Access Journals (Sweden)

    Jessie L Carviel

    Full Text Available A whole-genome sequencing technique developed to identify fast neutron-induced deletion mutations revealed that iap1-1 is a new allele of EDS5 (eds5-5. RPS2-AvrRpt2-initiated effector-triggered immunity (ETI was compromised in iap1-1/eds5-5 with respect to in planta bacterial levels and the hypersensitive response, while intra- and intercellular free salicylic acid (SA accumulation was greatly reduced, suggesting that SA contributes as both an intracellular signaling molecule and an antimicrobial agent in the intercellular space during ETI. During the compatible interaction between wild-type Col-0 and virulent Pseudomonas syringae pv. tomato (Pst, little intercellular free SA accumulated, which led to the hypothesis that Pst suppresses intercellular SA accumulation. When Col-0 was inoculated with a coronatine-deficient strain of Pst, high levels of intercellular SA accumulation were observed, suggesting that Pst suppresses intercellular SA accumulation using its phytotoxin coronatine. This work suggests that accumulation of SA in the intercellular space is an important component of basal/PAMP-triggered immunity as well as ETI to pathogens that colonize the intercellular space.

  11. Bright luminescence of Vibrio fischeri aconitase mutants reveals a connection between citrate and the Gac/Csr regulatory system.

    Science.gov (United States)

    Septer, Alecia N; Bose, Jeffrey L; Lipzen, Anna; Martin, Joel; Whistler, Cheryl; Stabb, Eric V

    2015-01-01

    The Gac/Csr regulatory system is conserved throughout the γ-proteobacteria and controls key pathways in central carbon metabolism, quorum sensing, biofilm formation and virulence in important plant and animal pathogens. Here we show that elevated intracellular citrate levels in a Vibrio fischeri aconitase mutant correlate with activation of the Gac/Csr cascade and induction of bright luminescence. Spontaneous or directed mutations in the gene that encodes citrate synthase reversed the bright luminescence of aconitase mutants, eliminated their citrate accumulation and reversed their elevated expression of CsrB. Our data elucidate a correlative link between central metabolic and regulatory pathways, and they suggest that the Gac system senses a blockage at the aconitase step of the tricarboxylic acid cycle, either through elevated citrate levels or a secondary metabolic effect of citrate accumulation, and responds by modulating carbon flow and various functions associated with host colonization, including bioluminescence. © 2014 John Wiley & Sons Ltd.

  12. The glossyhead1 allele of acc1 reveals a principal role for multidomain acetyl-coenzyme a carboxylase in the biosynthesis of cuticular waxes by Arabidopsis

    KAUST Repository

    Lu, Shiyou; Zhao, Huayan; Parsons, Eugene P.; Xu, Changcheng; Kosma, Dylan K.; Xu, Xiaojing; Chao, Daiyin; Lohrey, Gregory T.; Bangarusamy, Dhinoth Kumar; Wang, Guangchao; Bressan, Ray Anthony; Jenks, Matthew A.

    2011-01-01

    A novel mutant of Arabidopsis (Arabidopsis thaliana), having highly glossy inflorescence stems, postgenital fusion in floral organs, and reduced fertility, was isolated from an ethyl methanesulfonate-mutagenized population and designated glossyhead1

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

    OpenAIRE

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

    2015-01-01

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

  14. The Arabidopsis aba4-1 Mutant Reveals a Specific Function for Neoxanthin in Protection against Photooxidative Stress[W

    Science.gov (United States)

    Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

    2007-01-01

    The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions. PMID:17351115

  15. The Arabidopsis aba4-1 mutant reveals a specific function for neoxanthin in protection against photooxidative stress.

    Science.gov (United States)

    Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

    2007-03-01

    The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions.

  16. Comparative proteomics of a tor inducible Aspergillus fumigatus mutant reveals involvement of the Tor kinase in iron regulation.

    Science.gov (United States)

    Baldin, Clara; Valiante, Vito; Krüger, Thomas; Schafferer, Lukas; Haas, Hubertus; Kniemeyer, Olaf; Brakhage, Axel A

    2015-07-01

    The Tor (target of rapamycin) kinase is one of the major regulatory nodes in eukaryotes. Here, we analyzed the Tor kinase in Aspergillus fumigatus, which is the most important airborne fungal pathogen of humans. Because deletion of the single tor gene was apparently lethal, we generated a conditional lethal tor mutant by replacing the endogenous tor gene by the inducible xylp-tor gene cassette. By both 2DE and gel-free LC-MS/MS, we found that Tor controls a variety of proteins involved in nutrient sensing, stress response, cell cycle progression, protein biosynthesis and degradation, but also processes in mitochondria, such as respiration and ornithine metabolism, which is required for siderophore formation. qRT-PCR analyses indicated that mRNA levels of ornithine biosynthesis genes were increased under iron limitation. When tor was repressed, iron regulation was lost. In a deletion mutant of the iron regulator HapX also carrying the xylp-tor cassette, the regulation upon iron deprivation was similar to that of the single tor inducible mutant strain. In line, hapX expression was significantly reduced when tor was repressed. Thus, Tor acts either upstream of HapX or independently of HapX as a repressor of the ornithine biosynthesis genes and thereby regulates the production of siderophores. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Genetic analysis of plant height in induced mutants of aromatic rice

    International Nuclear Information System (INIS)

    Kole, P.C.

    2005-01-01

    Inheritance of plant height in five gamma-ray induced mutants of aromatic rice cultivar Gobindabhog was studied through 6 x 6 diallel cross and segregation analyses. Diallel analysis revealed presence of additive and non-additive gene action with the preponderance of the latter. Proportion of dominant and recessive alleles was distributed unequally among the parents. The direction of dominance was towards tallness. The number of groups of genes was found to be three. The segregation analysis indicated the role of a single major recessive gene for height reduction in three mutants and, in another mutant, a single major recessive gene with negative modifiers. The other semi-dwarf mutant had two major recessive genes with almost equal effect in height reduction. The mutant allele(s) of the latter two mutants were non-allelic to sd sub(1) gene, which could be used as an alternative source of Dee Gee Woo Gen to widen the genetic diversity in semi-dwarfism [it

  18. Allele-specific gene expression patterns in primary leukemic cells reveal regulation of gene expression by CpG site methylation

    DEFF Research Database (Denmark)

    Milani, Lili; Lundmark, Anders; Nordlund, Jessica

    2008-01-01

    To identify genes that are regulated by cis-acting functional elements in acute lymphoblastic leukemia (ALL) we determined the allele-specific expression (ASE) levels of 2, 529 genes by genotyping a genome-wide panel of single nucleotide polymorphisms in RNA and DNA from bone marrow and blood...

  19. Time-Resolved Tracking of Mutations Reveals Diverse Allele Dynamics during Escherichia coli Antimicrobial Adaptive Evolution to Single Drugs and Drug Pairs

    DEFF Research Database (Denmark)

    Hickman, Rachel A.; Munck, Christian; Sommer, Morten Otto Alexander

    2017-01-01

    + CHL and CHL + CIP). We find that lineages evolved to antibiotic combinations exhibit different resistance allele dynamics compared with those of single-drug evolved lineages, especially for a drug pair with reciprocal collateral sensitivity. During adaptation, we observed interfering, superimposing...

  20. Mapping of barley alpha-amylases and outer subsite mutants reveals dynamic high-affinity subsites and barriers in the long substrate binding cleft

    DEFF Research Database (Denmark)

    Kandra, L.; Abou Hachem, Maher; Gyemant, G.

    2006-01-01

    Subsite affinity maps of long substrate binding clefts in barley alpha-amylases, obtained using a series of maltooligosaccharides of degree of polymerization of 3-12, revealed unfavorable binding energies at the internal subsites -3 and -5 and at subsites -8 and +3/+4 defining these subsites...... as binding barriers. Barley a-amylase I mutants Y105A and T212Y at subsite -6 and +4 resulted in release or anchoring of bound substrate, thus modifying the affinities of other high-affinity subsites (-2 and +2) and barriers. The double mutant Y105A-T212Y displayed a hybrid subsite affinity profile......, converting barriers to binding areas. These findings highlight the dynamic binding energy distribution and the versatility of long maltooligosaccharide derivatives in mapping extended binding clefts in a-amylases....

  1. A Medicago truncatula tobacco retrotransposon insertion mutant collection with defects in nodule development and symbiotic nitrogen fixation.

    Science.gov (United States)

    Pislariu, Catalina I; Murray, Jeremy D; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; Benedito, Vagner A; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S; Chen, Rujin; Udvardi, Michael K

    2012-08-01

    A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod-), 51 mutants with totally ineffective nodules (Nod+ Fix-), 17 mutants with partially ineffective nodules (Nod+ Fix+/-), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/- Fix-), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/- Fix+), and 11 supernodulating mutants (Nod++Fix+/-). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN'T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod- lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging.

  2. Nitric oxide synthase gene G298 allele

    International Nuclear Information System (INIS)

    Nagib El-Kilany, Galal E.; Nayel, Ehab; Hazzaa, Sahar

    2004-01-01

    Background: Nitric oxide (NO) has an important effect on blood pressure, arterial wall, and the basal release of endothelial NO in hypertension (HPN) may be reduced. Until now, there is no solid data revealing the potential role of the polymorphism of the nitric oxide synthase gene (NOS) in patients with HPN and microvascular angina. Aim: The aim of the present study is to investigate the gene of endothelial nitric oxide synthase (eNOS), as the polymorphism of this gene may be a putative candidate for HPN and initiate the process of atherosclerosis. Methods: Sixty participants were recruited for this study; 50 were hypertensive patients complaining of chest pain [30 of them have electrocardiogram (EKG) changes of ischemia], 20 had isolated HPN, and 10 healthy volunteers served as control. All patients underwent stress myocardial perfusion imaging (MPI) and coronary angiography. Genotyping of eNOS for all patients and controls was performed. The linkages between HPN, microvascular angina and eNOS gene polymorphism were investigated. Results: MPI and coronary angiography revealed that 15 patients had chest pain with true ischemia and reversible myocardial perfusion defects (multiple and mild) but normal epicardial coronary arteries (microvascular angina), while 15 patients had significant coronary artery disease (CAD), and 20 hypertensive patients showed normal perfusion scan and coronary angiography. The prevalence of the NOS G 298 allele was higher in the hypertensive group with microvascular angina (documented by MPI) than it was among the control participants (P<.005). The eNOS allele was significantly higher in the hypertensive group than in the control participants, but there was no significant difference in homozygote mutants among hypertensive participants, x-syndrome and patients with CAD. Conclusion: eNOS gene polymorphism is proved to be an important etiology in microvascular angina (x-syndrome) among hypertensive patients. In addition, the eNOS mutant

  3. Mechanism of enhanced conversion of 1,2,3-trichloropropane by mutant haloalkane dehalogenase revealed by molecular modeling

    Science.gov (United States)

    Banáš, Pavel; Otyepka, Michal; Jeřábek, Petr; Petřek, Martin; Damborský, Jiří

    2006-06-01

    1,2,3-Trichloropropane (TCP) is a highly toxic, recalcitrant byproduct of epichlorohydrin manufacture. Haloalkane dehalogenase (DhaA) from Rhodococcus sp. hydrolyses the carbon-halogen bond in various halogenated compounds including TCP, but with low efficiency ( k cat/ K m = 36 s-1 M-1). A Cys176Tyr-DhaA mutant with a threefold higher catalytic efficiency for TCP dehalogenation has been previously obtained by error-prone PCR. We have used molecular simulations and quantum mechanical calculations to elucidate the molecular mechanisms involved in the improved catalysis of the mutant, and enantioselectivity of DhaA toward TCP. The Cys176Tyr mutation modifies the protein access and export routes. Substitution of the Cys residue by the bulkier Tyr narrows the upper tunnel, making the second tunnel "slot" the preferred route. TCP can adopt two major orientations in the DhaA enzyme, in one of which the halide-stabilizing residue Asn41 forms a hydrogen bond with the terminal halogen atom of the TCP molecule, while in the other it bonds with the central halogen atom. The differences in these binding patterns explain the preferential formation of the ( R)- over the ( S)-enantiomer of 2,3-dichloropropane-1-ol in the reaction catalyzed by the enzyme.

  4. Analysis of Msx1; Msx2 double mutants reveals multiple roles for Msx genes in limb development.

    Science.gov (United States)

    Lallemand, Yvan; Nicola, Marie-Anne; Ramos, Casto; Bach, Antoine; Cloment, Cécile Saint; Robert, Benoît

    2005-07-01

    The homeobox-containing genes Msx1 and Msx2 are highly expressed in the limb field from the earliest stages of limb formation and, subsequently, in both the apical ectodermal ridge and underlying mesenchyme. However, mice homozygous for a null mutation in either Msx1 or Msx2 do not display abnormalities in limb development. By contrast, Msx1; Msx2 double mutants exhibit a severe limb phenotype. Our analysis indicates that these genes play a role in crucial processes during limb morphogenesis along all three axes. Double mutant limbs are shorter and lack anterior skeletal elements (radius/tibia, thumb/hallux). Gene expression analysis confirms that there is no formation of regions with anterior identity. This correlates with the absence of dorsoventral boundary specification in the anterior ectoderm, which precludes apical ectodermal ridge formation anteriorly. As a result, anterior mesenchyme is not maintained, leading to oligodactyly. Paradoxically, polydactyly is also frequent and appears to be associated with extended Fgf activity in the apical ectodermal ridge, which is maintained up to 14.5 dpc. This results in a major outgrowth of the mesenchyme anteriorly, which nevertheless maintains a posterior identity, and leads to formation of extra digits. These defects are interpreted in the context of an impairment of Bmp signalling.

  5. Use of bioreporters and deletion mutants reveals ionic silver and ROS to be equally important in silver nanotoxicity.

    Science.gov (United States)

    Joshi, Nimisha; Ngwenya, Bryne T; Butler, Ian B; French, Chris E

    2015-04-28

    The mechanism of antibacterial action of silver nanoparticles (AgNp) was investigated by employing a combination of microbiology and geochemical approaches to contribute to the realistic assessment of nanotoxicity. Our studies showed that suspending AgNp in media with different levels of chloride relevant to environmental conditions produced low levels of ionic silver thereby suggesting that dissolution of silver ions from nanoparticulate surface could not be the sole mechanism of toxicity. An Escherichia coli based bioreporter strain responsive to silver ions together with mutant strains of E. coli lacking specific protective systems were tested against AgNp. Deletion mutants lacking silver ion efflux systems and resistance mechanisms against oxidative stress showed an increased sensitivity to AgNp. However, the bioreporter did not respond to silver nanoparticles. Our results suggest that oxidative stress is a major toxicity mechanism and that this is at least partially associated with ionic silver, but that bulk dissolution of silver into the medium is not sufficient to account for the observed effects. Chloride ions do not appear to offer significant protection, indicating that chloride in receiving waters will not necessarily protect environmental bacteria from the toxic effects of nanoparticles in effluents. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Arabidopsis mutant sk156 reveals complex regulation of SPL15 in a miR156-controlled gene network.

    Science.gov (United States)

    Wei, Shu; Gruber, Margaret Y; Yu, Bianyun; Gao, Ming-Jun; Khachatourians, George G; Hegedus, Dwayne D; Parkin, Isobel A P; Hannoufa, Abdelali

    2012-09-18

    The Arabidopsis microRNA156 (miR156) regulates 11 members of the SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) family by base pairing to complementary target mRNAs. Each SPL gene further regulates a set of other genes; thus, miR156 controls numerous genes through a complex gene regulation network. Increased axillary branching occurs in transgenic Arabidopsis overexpressing miR156b, similar to that observed in loss-of-function max3 and max4 mutants with lesions in carotenoid cleavage dioxygenases. Arabidopsis miR156b was found to enhance carotenoid levels and reproductive shoot branching when expressed in Brassica napus, suggesting a link between miR156b expression and carotenoid metabolism. However, details of the miR156 regulatory network of SPL genes related to carotenoid metabolism are not known. In this study, an Arabidopsis T-DNA enhancer mutant, sk156, was identified due to its altered branching and trichome morphology and increased seed carotenoid levels compared to wild type (WT) ecovar Columbia. Enhanced miR156b expression due to the 35S enhancers present on the T-DNA insert was responsible for these phenotypes. Constitutive and leaf primodium-specific expression of a miR156-insensitive (mutated) SPL15 (SPL15m) largely restored WT seed carotenoid levels and plant morphology when expressed in sk156. The Arabidopsis native miR156-sensitive SPL15 (SPL15n) and SPL15m driven by a native SPL15 promoter did not restore the WT phenotype in sk156. Our findings suggest that SPL15 function is somewhat redundant with other SPL family members, which collectively affect plant phenotypes. Moreover, substantially decreased miR156b transcript levels in sk156 expressing SPL15m, together with the presence of multiple repeats of SPL-binding GTAC core sequence close to the miR156b transcription start site, suggested feedback regulation of miR156b expression by SPL15. This was supported by the demonstration of specific in vitro interaction between DNA-binding SBP domain of SPL15

  7. Arabidopsis mutant sk156 reveals complex regulation of SPL15 in a miR156-controlled gene network

    Directory of Open Access Journals (Sweden)

    Wei Shu

    2012-09-01

    Full Text Available Abstract Background The Arabidopsis microRNA156 (miR156 regulates 11 members of the SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL family by base pairing to complementary target mRNAs. Each SPL gene further regulates a set of other genes; thus, miR156 controls numerous genes through a complex gene regulation network. Increased axillary branching occurs in transgenic Arabidopsis overexpressing miR156b, similar to that observed in loss-of-function max3 and max4 mutants with lesions in carotenoid cleavage dioxygenases. Arabidopsis miR156b was found to enhance carotenoid levels and reproductive shoot branching when expressed in Brassica napus, suggesting a link between miR156b expression and carotenoid metabolism. However, details of the miR156 regulatory network of SPL genes related to carotenoid metabolism are not known. Results In this study, an Arabidopsis T-DNA enhancer mutant, sk156, was identified due to its altered branching and trichome morphology and increased seed carotenoid levels compared to wild type (WT ecovar Columbia. Enhanced miR156b expression due to the 35S enhancers present on the T-DNA insert was responsible for these phenotypes. Constitutive and leaf primodium-specific expression of a miR156-insensitive (mutated SPL15 (SPL15m largely restored WT seed carotenoid levels and plant morphology when expressed in sk156. The Arabidopsis native miR156-sensitive SPL15 (SPL15n and SPL15m driven by a native SPL15 promoter did not restore the WT phenotype in sk156. Our findings suggest that SPL15 function is somewhat redundant with other SPL family members, which collectively affect plant phenotypes. Moreover, substantially decreased miR156b transcript levels in sk156 expressing SPL15m, together with the presence of multiple repeats of SPL-binding GTAC core sequence close to the miR156b transcription start site, suggested feedback regulation of miR156b expression by SPL15. This was supported by the demonstration of specific in vitro

  8. Changes in allelic frequency over time in European bread wheat (Triticum aestivum L.) varieties revealed using DArT and SSR markers

    DEFF Research Database (Denmark)

    Orabi, Jihad; Jahoor, Ahmed; Backes, Gunter Martin

    2014-01-01

    A collection of 189 bread wheat landraces and cultivars, primarily of European origin, released between 1886 and 2009, was analyzed using two DNA marker systems. A set of 76 SSR markers and ~7,000 DArT markers distributed across the wheat genome were employed in these analyses. All of the SSR...... markers were found to be polymorphic, whereas only 2,532 of the ~7,000 DArT markers were polymorphic. A Mantel test between the genetic distances calculated based on the SSR and DArT data showed a strong positive correlation between the two marker types, with a Pearson's value (r) of 0.66. We assessed...... the genetic diversity and allelic frequencies among the accessions based on spring- versus winter-wheat type as well as between landraces and cultivars. We also analyzed the changes in genetic diversity and allelic frequencies in these samples over time. We observed separation based on both vernalization type...

  9. Genetic Correction of SOD1 Mutant iPSCs Reveals ERK and JNK Activated AP1 as a Driver of Neurodegeneration in Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Akshay Bhinge

    2017-04-01

    Full Text Available Summary: Although mutations in several genes with diverse functions have been known to cause amyotrophic lateral sclerosis (ALS, it is unknown to what extent causal mutations impinge on common pathways that drive motor neuron (MN-specific neurodegeneration. In this study, we combined induced pluripotent stem cells-based disease modeling with genome engineering and deep RNA sequencing to identify pathways dysregulated by mutant SOD1 in human MNs. Gene expression profiling and pathway analysis followed by pharmacological screening identified activated ERK and JNK signaling as key drivers of neurodegeneration in mutant SOD1 MNs. The AP1 complex member JUN, an ERK/JNK downstream target, was observed to be highly expressed in MNs compared with non-MNs, providing a mechanistic insight into the specific degeneration of MNs. Importantly, investigations of mutant FUS MNs identified activated p38 and ERK, indicating that network perturbations induced by ALS-causing mutations converge partly on a few specific pathways that are drug responsive and provide immense therapeutic potential. : In this article, Bhinge, Stanton, and colleagues use genome editing of patient-derived iPSCs to model ALS phenotypic defects in vitro. Transcriptomic analysis of disease MNs reveals activation of MAPK, AP1, WNT, cell-cycle, and p53 signaling in ALS MNs. Pharmacological screening uncovers activated ERK and JNK signaling as therapeutic targets in ALS. Keywords: ALS, SOD1, FUS, CRISPR-Cas9, p38, ERK, JNK, WNT, TP53, JUN

  10. Dissemination of the highly expressed Bx7 glutenin subunit (Glu-B1al allele) in wheat as revealed by novel PCR markers and RP-HPLC.

    Science.gov (United States)

    Butow, B J; Gale, K R; Ikea, J; Juhász, A; Bedö, Z; Tamás, L; Gianibelli, M C

    2004-11-01

    Increased expression of the high molecular weight glutenin subunit (HMW-GS) Bx7 is associated with improved dough strength of wheat (Triticum aestivum L.) flour. Several cultivars and landraces of widely different genetic backgrounds from around the world have now been found to contain this so-called 'over-expressing' allelic form of the Bx7 subunit encoded by Glu-B1al. Using three methods of identification, SDS-PAGE, RP-HPLC and PCR marker analysis, as well as pedigree information, we have traced the distribution and source of this allele from a Uruguayan landrace, Americano 44D, in the mid-nineteenth century. Results are supported by knowledge of the movement of wheat lines with migrants. All cultivars possessing the Glu-B1al allele can be identified by the following attributes: (1) the elution of the By sub-unit peak before the Dx sub-unit peak by RP-HPLC, (2) high expression levels of Bx7 (>39% Mol% Bx), (3) a 43 bp insertion in the matrix-attachment region (MAR) upstream of the gene promoter relative to Bx7 and an 18 bp nucleotide duplication in the coding region of the gene. Evidence is presented indicating that these 18 and 43 bp sequence insertions are not causal for the high expression levels of Bx7 as they were also found to be present in a small number of hexaploid species, including Chinese Spring, and species expressing Glu-B1ak and Glu-B1a alleles. In addition, these sequence inserts were found in different isolates of the tetraploid wheat, T. turgidum, indicating that these insertion/deletion events occurred prior to hexaploidization.

  11. Comparison of identical and functional Igh alleles reveals a nonessential role for Eμ in somatic hypermutation and class-switch recombination.

    Science.gov (United States)

    Li, Fubin; Yan, Yi; Pieretti, Joyce; Feldman, Danielle A; Eckhardt, Laurel A

    2010-11-15

    Somatic hypermutation (SHM), coupled with Ag selection, provides a mechanism for generating Abs with high affinity for invading pathogens. Class-switch recombination (CSR) ensures that these Abs attain pathogen-appropriate effector functions. Although the enzyme critical to both processes, activation-induced cytidine deaminase, has been identified, it remains unclear which cis-elements within the Ig loci are responsible for recruiting activation-induced cytidine deaminase and promoting its activity. Studies showed that Ig gene-transcription levels are positively correlated with the frequency of SHM and CSR, making the intronic, transcriptional enhancer Eμ a likely contributor to both processes. Tests of this hypothesis yielded mixed results arising, in part, from the difficulty in studying B cell function in mice devoid of Eμ. In Eμ's absence, V(H) gene assembly is dramatically impaired, arresting B cell development. The current study circumvented this problem by modifying the murine Igh locus through simultaneous insertion of a fully assembled V(H) gene and deletion of Eμ. The behavior of this allele was compared with that of a matched allele carrying the same V(H) gene but with Eμ intact. Although IgH transcription was as great or greater on the Eμ-deficient allele, CSR and SHM were consistently, but modestly, reduced relative to the allele in which Eμ remained intact. We conclude that Eμ contributes to, but is not essential for, these complex processes and that its contribution is not as a transcriptional enhancer but, rather, is at the level of recruitment and/or activation of the SHM/CSR machinery.

  12. A genome-wide screen in human embryonic stem cells reveals novel sites of allele-specific histone modification associated with known disease loci

    LENUS (Irish Health Repository)

    Prendergast, James G D

    2012-05-19

    AbstractBackgroundChromatin structure at a given site can differ between chromosome copies in a cell, and such imbalances in chromatin structure have been shown to be important in understanding the molecular mechanisms controlling several disease loci. Human genetic variation, DNA methylation, and disease have been intensely studied, uncovering many sites of allele-specific DNA methylation (ASM). However, little is known about the genome-wide occurrence of sites of allele-specific histone modification (ASHM) and their relationship to human disease. The aim of this study was to investigate the extent and characteristics of sites of ASHM in human embryonic stem cells (hESCs).ResultsUsing a statistically rigorous protocol, we investigated the genomic distribution of ASHM in hESCs, and their relationship to sites of allele-specific expression (ASE) and DNA methylation. We found that, although they were rare, sites of ASHM were substantially enriched at loci displaying ASE. Many were also found at known imprinted regions, hence sites of ASHM are likely to be better markers of imprinted regions than sites of ASM. We also found that sites of ASHM and ASE in hESCs colocalize at risk loci for developmental syndromes mediated by deletions, providing insights into the etiology of these disorders.ConclusionThese results demonstrate the potential importance of ASHM patterns in the interpretation of disease loci, and the protocol described provides a basis for similar studies of ASHM in other cell types to further our understanding of human disease susceptibility.

  13. Chemical Genomic Screening of a Saccharomyces cerevisiae Genomewide Mutant Collection Reveals Genes Required for Defense against Four Antimicrobial Peptides Derived from Proteins Found in Human Saliva

    Science.gov (United States)

    Bhatt, Sanjay; Schoenly, Nathan E.; Lee, Anna Y.; Nislow, Corey; Bobek, Libuse A.

    2013-01-01

    To compare the effects of four antimicrobial peptides (MUC7 12-mer, histatin 12-mer, cathelicidin KR20, and a peptide containing lactoferricin amino acids 1 to 11) on the yeast Saccharomyces cerevisiae, we employed a genomewide fitness screen of combined collections of mutants with homozygous deletions of nonessential genes and heterozygous deletions of essential genes. When an arbitrary fitness score cutoffs of 1 (indicating a fitness defect, or hypersensitivity) and −1 (indicating a fitness gain, or resistance) was used, 425 of the 5,902 mutants tested exhibited altered fitness when treated with at least one peptide. Functional analysis of the 425 strains revealed enrichment among the identified deletions in gene groups associated with the Gene Ontology (GO) terms “ribosomal subunit,” “ribosome biogenesis,” “protein glycosylation,” “vacuolar transport,” “Golgi vesicle transport,” “negative regulation of transcription,” and others. Fitness profiles of all four tested peptides were highly similar, particularly among mutant strains exhibiting the greatest fitness defects. The latter group included deletions in several genes involved in induction of the RIM101 signaling pathway, including several components of the ESCRT sorting machinery. The RIM101 signaling regulates response of yeasts to alkaline and neutral pH and high salts, and our data indicate that this pathway also plays a prominent role in regulating protective measures against all four tested peptides. In summary, the results of the chemical genomic screens of S. cerevisiae mutant collection suggest that the four antimicrobial peptides, despite their differences in structure and physical properties, share many interactions with S. cerevisiae cells and consequently a high degree of similarity between their modes of action. PMID:23208710

  14. Transcriptome Comparative Profiling of Barley eibi1 Mutant Reveals Pleiotropic Effects of HvABCG31 Gene on Cuticle Biogenesis and Stress Responsive Pathways

    Directory of Open Access Journals (Sweden)

    Eviatar Nevo

    2013-10-01

    Full Text Available Wild barley eibi1 mutant with HvABCG31 gene mutation has low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. To better understand how such a mutant plant survives, we performed a genome-wide gene expression analysis. The leaf transcriptomes between the near-isogenic lines eibi1 and the wild type were compared using the 22-k Barley1 Affymetrix microarray. We found that the pleiotropic effect of the single gene HvABCG31 mutation was linked to the co-regulation of metabolic processes and stress-related system. The cuticle development involved cytochrome P450 family members and fatty acid metabolism pathways were significantly up-regulated by the HvABCG31 mutation, which might be anticipated to reduce the levels of cutin monomers or wax and display conspicuous cuticle defects. The candidate genes for responses to stress were induced by eibi1 mutant through activating the jasmonate pathway. The down-regulation of co-expressed enzyme genes responsible for DNA methylation and histone deacetylation also suggested that HvABCG31 mutation may affect the epigenetic regulation for barley development. Comparison of transcriptomic profiling of barley under biotic and abiotic stresses revealed that the functions of HvABCG31 gene to high-water loss rate might be different from other osmotic stresses of gene mutations in barley. The transcriptional profiling of the HvABCG31 mutation provided candidate genes for further investigation of the physiological and developmental changes caused by the mutant.

  15. Heterozygosity for an in-frame deletion causes glutaryl-CoA dehydrogenase deficiency in a patient detected by newborn screening: investigation of the effect of the mutant allele

    DEFF Research Database (Denmark)

    Bross, Peter; Frederiksen, Jane B; Bie, Anne S

    2012-01-01

    the proband were consistent with a mild biochemical GA-1 phenotype. Recombinant expression of the mutant variant in E. coli showed that the GCDH-(p.Gly185_Ser190del) protein displayed severely decreased assembly into tetramers and enzyme activity. To discover a potential dominant negative effect of the mutant...... with the hypothesis that heterozygosity for this mutation confers a dominant negative effect resulting in a GCDH enzyme activity that is significantly lower than the expected 50%....

  16. Chinese hamster ovary cell mutants defective in heparan sulfate biosynthesis

    International Nuclear Information System (INIS)

    Bame, K.J.; Kiser, C.S.; Esko, J.D.

    1987-01-01

    The authors have isolated Chinese hamster ovary cell mutants defective in proteoglycan synthesis by radiographic screening for cells unable to incorporate 35 SO 4 into acid-precipitable material. Some mutants did not incorporate 35 SO 4 into acid-precipitable material, whereas others incorporated about 3-fold less radioactivity. HPLC anion exchange chromatographic analysis of radiolabelled glycosaminoglycans isolated from these mutants revealed many are defective in heparan sulfate biosynthesis. Mutants 803 and 677 do not synthesize heparan sulfate, although they produce chondroitin sulfate: strain 803 makes chondroitin sulfate normally, whereas 677 overaccumulates chondroitin sulfate by a factor of three. These mutants fall into the same complementation group, suggesting that the mutations are allelic. A second group of heparan sulfate biosynthetic mutants, consisting of cell lines 625, 668 and 679, produce undersulfated heparan sulfate and normal chondroitin sulfate. Treatment of the chains with nitrous acid should determine the position of the sulfate groups along the chain. These mutants may define a complementation group that is defective in the enzymes which modify the heparan sulfate chain. To increase the authors repertoire of heparan sulfate mutants, they are presently developing an in situ enzyme assay to screen colonies replica plated on filter discs for sulfotransferase defects

  17. A Rice gid1 Suppressor Mutant Reveals That Gibberellin Is Not Always Required for Interaction between Its Receptor, GID1, and DELLA Proteins[W][OA

    Science.gov (United States)

    Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

    2010-01-01

    To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1P99S interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1P99A has smaller Ka (association) and Kd (dissociation) values for GA4 than does wild-type GID1. This suggests that the GID1P99A lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1P99A. Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants. PMID:21098733

  18. A rice gid1 suppressor mutant reveals that gibberellin is not always required for interaction between its receptor, GID1, and DELLA proteins.

    Science.gov (United States)

    Yamamoto, Yuko; Hirai, Takaaki; Yamamoto, Eiji; Kawamura, Mayuko; Sato, Tomomi; Kitano, Hidemi; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

    2010-11-01

    To investigate gibberellin (GA) signaling using the rice (Oryza sativa) GA receptor GIBBERELLIN-INSENSITIVE DWARF1 (GID1) mutant gid1-8, we isolated a suppressor mutant, Suppressor of gid1-1 (Sgd-1). Sgd-1 is an intragenic mutant containing the original gid1-8 mutation (L45F) and an additional amino acid substitution (P99S) in the loop region. GID1(P99S) interacts with the rice DELLA protein SLENDER RICE1 (SLR1), even in the absence of GA. Substitution of the 99th Pro with other amino acids revealed that substitution with Ala (P99A) caused the highest level of GA-independent interaction. Physicochemical analysis using surface plasmon resonance revealed that GID1(P99A) has smaller K(a) (association) and K(d) (dissociation) values for GA(4) than does wild-type GID1. This suggests that the GID1(P99A) lid is at least partially closed, resulting in both GA-independent and GA-hypersensitive interactions with SLR1. One of the three Arabidopsis thaliana GID1s, At GID1b, can also interact with DELLA proteins in the absence of GA, so we investigated whether GA-independent interaction of At GID1b depends on a mechanism similar to that of rice GID1(P99A). Substitution of the loop region or a few amino acids of At GID1b with those of At GID1a diminished its GA-independent interaction with GAI while maintaining the GA-dependent interaction. Soybean (Glycine max) and Brassica napus also have GID1s similar to At GID1b, indicating that these unique GID1s occur in various dicots and may have important functions in these plants.

  19. Comparative Genomic Analysis of Transgenic Poplar Dwarf Mutant Reveals Numerous Differentially Expressed Genes Involved in Energy Flow

    Directory of Open Access Journals (Sweden)

    Su Chen

    2014-09-01

    Full Text Available In our previous research, the Tamarix androssowii LEA gene (Tamarix androssowii late embryogenesis abundant protein Mrna, GenBank ID: DQ663481 was transferred into Populus simonii × Populus nigra. Among the eleven transgenic lines, one exhibited a dwarf phenotype compared to the wild type and other transgenic lines, named dwf1. To uncover the mechanisms underlying this phenotype, digital gene expression libraries were produced from dwf1, wild-type, and other normal transgenic lines, XL-5 and XL-6. Gene expression profile analysis indicated that dwf1 had a unique gene expression pattern in comparison to the other two transgenic lines. Finally, a total of 1246 dwf1-unique differentially expressed genes were identified. These genes were further subjected to gene ontology and pathway analysis. Results indicated that photosynthesis and carbohydrate metabolism related genes were significantly affected. In addition, many transcription factors genes were also differentially expressed in dwf1. These various differentially expressed genes may be critical for dwarf mutant formation; thus, the findings presented here might provide insight for our understanding of the mechanisms of tree growth and development.

  20. RNAseq analysis reveals pathways and candidate genes associated with salinity tolerance in a spaceflight-induced wheat mutant.

    Science.gov (United States)

    Xiong, Hongchun; Guo, Huijun; Xie, Yongdun; Zhao, Linshu; Gu, Jiayu; Zhao, Shirong; Li, Junhui; Liu, Luxiang

    2017-06-02

    Salinity stress has become an increasing threat to food security worldwide and elucidation of the mechanism for salinity tolerance is of great significance. Induced mutation, especially spaceflight mutagenesis, is one important method for crop breeding. In this study, we show that a spaceflight-induced wheat mutant, named salinity tolerance 1 (st1), is a salinity-tolerant line. We report the characteristics of transcriptomic sequence variation induced by spaceflight, and show that mutations in genes associated with sodium ion transport may directly contribute to salinity tolerance in st1. Furthermore, GO and KEGG enrichment analysis of differentially expressed genes (DEGs) between salinity-treated st1 and wild type suggested that the homeostasis of oxidation-reduction process is important for salt tolerance in st1. Through KEGG pathway analysis, "Butanoate metabolism" was identified as a new pathway for salinity responses. Additionally, key genes for salinity tolerance, such as genes encoding arginine decarboxylase, polyamine oxidase, hormones-related, were not only salt-induced in st1 but also showed higher expression in salt-treated st1 compared with salt-treated WT, indicating that these genes may play important roles in salinity tolerance in st1. This study presents valuable genetic resources for studies on transcriptome variation caused by induced mutation and the identification of salt tolerance genes in crops.

  1. Zebrafish scarb2a insertional mutant reveals a novel function for the Scarb2/Limp2 receptor in notochord development.

    Science.gov (United States)

    Diaz-Tellez, Abigail; Zampedri, Cecilia; Ramos-Balderas, Jose L; García-Hernández, Fernando; Maldonado, Ernesto

    2016-04-01

    Scarb2 or Limp2 belong to a subfamily of Scavenger receptors described as lysosomal transmembrane glycosylated receptors, that are mutated in the human syndrome AMRF (action myoclonus-renal failure). The zebrafish insertional mutant scarb2a(hi1463Tg) has notochord defects, the notochord is a defining feature of chordates running along the center of the longitudinal axis and it is essential for forming the spinal column in all vertebrates. There are three paralogous scarb2 genes in zebrafish; scarb2a, scarb2b, and scarb2c. Both Scarb2a and Scarb2b proteins lack the classical di-leucine motif. We found that scarb2a(hi1463Tg) homozygous zebrafish embryos have a null mutation impairing vacuole formation in the notochord and simultaneously disrupting proper formation of the basement membrane resulting in its thickening at the ventral side of the notochord, which may be the cause for the anomalous upward bending observed in the trunk. Through whole-mount in situ hybridization, we detected scarb2a mRNA expression in the notochord and in the brain early in development. However, it is puzzling that scarb2a notochord mRNA expression is short-lived in the presumptive notochord and precedes the complete differentiation of the notochord. This work describes a novel function for the Scarb2 receptor as an essential glycoprotein for notochord development. © 2016 Wiley Periodicals, Inc.

  2. Experimental feline enteric coronavirus infection reveals an aberrant infection pattern and shedding of mutants with impaired infectivity in enterocyte cultures

    Science.gov (United States)

    Desmarets, Lowiese M. B.; Vermeulen, Ben L.; Theuns, Sebastiaan; Conceição-Neto, Nádia; Zeller, Mark; Roukaerts, Inge D. M.; Acar, Delphine D.; Olyslaegers, Dominique A. J.; Van Ranst, Marc; Matthijnssens, Jelle; Nauwynck, Hans J.

    2016-01-01

    Feline infectious peritonitis (FIP) results from mutations in the viral genome during a common feline enteric coronavirus (FECV) infection. Since many virological and immunological data on FECV infections are lacking, the present study investigated these missing links during experimental infection of three SPF cats with FECV strain UCD. Two cats showed mild clinical signs, faecal shedding of infectious virus from 4 dpi, a cell-associated viraemia at inconsistent time points from 5 dpi, a highly neutralising antibody response from 9 dpi, and no major abnormalities in leukocyte numbers. Faecal shedding lasted for 28–56 days, but virus shed during this stage was less infectious in enterocyte cultures and affected by mutations. Remarkably, in the other cat neither clinical signs nor acute shedding were seen, but virus was detected in blood cells from 3 dpi, and shedding of non-enterotropic, mutated viruses suddenly occurred from 14 dpi onwards. Neutralising antibodies arose from 21 dpi. Leukocyte numbers were not different compared to the other cats, except for the CD8+ regulatory T cells. These data indicate that FECV can infect immune cells even in the absence of intestinal replication and raise the hypothesis that the gradual adaptation to these cells can allow non-enterotropic mutants to arise. PMID:26822958

  3. Revealing impaired pathways in the an11 mutant by high-throughput characterization of Petunia axillaris and Petunia inflata transcriptomes.

    Science.gov (United States)

    Zenoni, Sara; D'Agostino, Nunzio; Tornielli, Giovanni B; Quattrocchio, Francesca; Chiusano, Maria L; Koes, Ronald; Zethof, Jan; Guzzo, Flavia; Delledonne, Massimo; Frusciante, Luigi; Gerats, Tom; Pezzotti, Mario

    2011-10-01

    Petunia is an excellent model system, especially for genetic, physiological and molecular studies. Thus far, however, genome-wide expression analysis has been applied rarely because of the lack of sequence information. We applied next-generation sequencing to generate, through de novo read assembly, a large catalogue of transcripts for Petunia axillaris and Petunia inflata. On the basis of both transcriptomes, comprehensive microarray chips for gene expression analysis were established and used for the analysis of global- and organ-specific gene expression in Petunia axillaris and Petunia inflata and to explore the molecular basis of the seed coat defects in a Petunia hybrida mutant, anthocyanin 11 (an11), lacking a WD40-repeat (WDR) transcription regulator. Among the transcripts differentially expressed in an11 seeds compared with wild type, many expected targets of AN11 were found but also several interesting new candidates that might play a role in morphogenesis of the seed coat. Our results validate the combination of next-generation sequencing with microarray analyses strategies to identify the transcriptome of two petunia species without previous knowledge of their genome, and to develop comprehensive chips as useful tools for the analysis of gene expression in P. axillaris, P. inflata and P. hybrida. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  4. Population genetics of Phytophthora infestans in Denmark reveals dominantly clonal populations and specific alleles linked to metalaxyl-M resistance

    DEFF Research Database (Denmark)

    Montes, M. S.; Nielsen, Bent Jørgen; Schmidt, S. G.

    2016-01-01

    population of P. infestans was characterized over the course of the 2013 growing season, as was the population genetic structure, using simple sequence repeat (SSR) genotypes and single nucleotide polymorphism (SNP)-based mitochondrial haplotyping of over 80 isolates. Both mating types A1 and A2 were present...... in most fields, but tests for recombination showed that clonal reproduction dominates in Danish populations. Genotype was not linked to haplotype and no differentiation was observed at the haplotype level, but rather between fields. Resistance phenotypes were linked to specific SSR alleles, demonstrating...

  5. The pht4;1-3 mutant line contains a loss of function allele in the Fatty Acid Desaturase 7 gene caused by a remnant inactivated selection marker-a cautionary tale.

    Science.gov (United States)

    Nilsson, Anders K; Andersson, Mats X

    2017-01-01

    A striking and unexpected biochemical phenotype was found in an insertion mutant line in the model plant Arabidopsis thaliana . One of two investigated insertion mutant lines in the gene encoding the phosphate transporter PHT4;1 demonstrated a prominent loss of trienoic fatty acids, whereas the other insertion line was indistinguishable from wild type in this aspect. We demonstrate that the loss of trienoic fatty acids was due to a remnant inactive negative selection marker gene in this particular transposon tagged line, pht4;1-3 . This constitutes a cautionary tale that warns of the importance to confirm the loss of this type of selection markers and the importance of verifying the relationship between a phenotype and genotype by more than one independent mutant line or alternatively genetic complementation.

  6. A transposon mutant library of Bacillus cereus ATCC 10987 reveals novel genes required for biofilm formation and implicates motility as an important factor for pellicle-biofilm formation.

    Science.gov (United States)

    Okshevsky, Mira; Louw, Matilde Greve; Lamela, Elena Otero; Nilsson, Martin; Tolker-Nielsen, Tim; Meyer, Rikke Louise

    2018-04-01

    Bacillus cereus is one of the most common opportunistic pathogens causing foodborne illness, as well as a common source of contamination in the dairy industry. B. cereus can form robust biofilms on food processing surfaces, resulting in food contamination due to shedding of cells and spores. Despite the medical and industrial relevance of this species, the genetic basis of biofilm formation in B. cereus is not well studied. In order to identify genes required for biofilm formation in this bacterium, we created a library of 5000 +  transposon mutants of the biofilm-forming strain B. cereusATCC 10987, using an unbiased mariner transposon approach. The mutant library was screened for the ability to form a pellicle biofilm at the air-media interface, as well as a submerged biofilm at the solid-media interface. A total of 91 genes were identified as essential for biofilm formation. These genes encode functions such as chemotaxis, amino acid metabolism and cellular repair mechanisms, and include numerous genes not previously known to be required for biofilm formation. Although the majority of disrupted genes are not directly responsible for motility, further investigations revealed that the vast majority of the biofilm-deficient mutants were also motility impaired. This observation implicates motility as a pivotal factor in the formation of a biofilm by B. cereus. These results expand our knowledge of the fundamental molecular mechanisms of biofilm formation by B. cereus. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  7. Analysis of Metal-Binding Features of the Wild Type and Two Domain-Truncated Mutant Variants of Littorina littorea Metallothionein Reveals Its Cd-Specific Character

    Directory of Open Access Journals (Sweden)

    Òscar Palacios

    2017-07-01

    Full Text Available After the resolution of the 3D structure of the Cd9-aggregate of the Littorina littorea metallothionein (MT, we report here a detailed analysis of the metal binding capabilities of the wild type MT, LlwtMT, and of two truncated mutants lacking either the N-terminal domain, Lltr2MT, or both the N-terminal domain, plus four extra flanking residues (SSVF, Lltr1MT. The recombinant synthesis and in vitro studies of these three proteins revealed that LlwtMT forms unique M9-LlwtMT complexes with Zn(II and Cd(II, while yielding a complex mixture of heteronuclear Zn,Cu-LlwtMT species with Cu(I. As expected, the truncated mutants gave rise to unique M6-LltrMT complexes and Zn,Cu-LltrMT mixtures of lower stoichiometry with respect to LlwtMT, with the SSVF fragment having an influence on their metal binding performance. Our results also revealed a major specificity, and therefore a better metal-coordinating performance of the three proteins for Cd(II than for Zn(II, although the analysis of the Zn(II/Cd(II displacement reaction clearly demonstrates a lack of any type of cooperativity in Cd(II binding. Contrarily, the analysis of their Cu(I binding abilities revealed that every LlMT domain is prone to build Cu4-aggregates, the whole MT working by modules analogously to, as previously described, certain fungal MTs, like those of C. neoformans and T. mesenterica. It is concluded that the Littorina littorea MT is a Cd-specific protein that (beyond its extended binding capacity through an additional Cd-binding domain confers to Littorina littorea a particular adaptive advantage in its changeable marine habitat.

  8. A systematic analysis of TCA Escherichia coli mutants reveals suitable genetic backgrounds for enhanced hydrogen and ethanol production using glycerol as main carbon source.

    Science.gov (United States)

    Valle, Antonio; Cabrera, Gema; Muhamadali, Howbeer; Trivedi, Drupad K; Ratray, Nicholas J W; Goodacre, Royston; Cantero, Domingo; Bolivar, Jorge

    2015-09-01

    Biodiesel has emerged as an environmentally friendly alternative to fossil fuels; however, the low price of glycerol feed-stocks generated from the biodiesel industry has become a burden to this industry. A feasible alternative is the microbial biotransformation of waste glycerol to hydrogen and ethanol. Escherichia coli, a microorganism commonly used for metabolic engineering, is able to biotransform glycerol into these products. Nevertheless, the wild type strain yields can be improved by rewiring the carbon flux to the desired products by genetic engineering. Due to the importance of the central carbon metabolism in hydrogen and ethanol synthesis, E. coli single null mutant strains for enzymes of the TCA cycle and other related reactions were studied in this work. These strains were grown anaerobically in a glycerol-based medium and the concentrations of ethanol, glycerol, succinate and hydrogen were analysed by HPLC and GC. It was found that the reductive branch is the more relevant pathway for the aim of this work, with malate playing a central role. It was also found that the putative C4-transporter dcuD mutant improved the target product yields. These results will contribute to reveal novel metabolic engineering strategies for improving hydrogen and ethanol production by E. coli. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The Arabidopsis nox Mutant Lacking Carotene Hydroxylase Activity Reveals a Critical Role for Xanthophylls in Photosystem I Biogenesis[C][W

    Science.gov (United States)

    Dall’Osto, Luca; Piques, Maria; Ronzani, Michela; Molesini, Barbara; Alboresi, Alessandro; Cazzaniga, Stefano; Bassi, Roberto

    2013-01-01

    Carotenes, and their oxygenated derivatives xanthophylls, are essential components of the photosynthetic apparatus. They contribute to the assembly of photosynthetic complexes and participate in light absorption and chloroplast photoprotection. Here, we studied the role of xanthophylls, as distinct from that of carotenes, by characterizing a no xanthophylls (nox) mutant of Arabidopsis thaliana, which was obtained by combining mutations targeting the four carotenoid hydroxylase genes. nox plants retained α- and β-carotenes but were devoid in xanthophylls. The phenotype included depletion of light-harvesting complex (LHC) subunits and impairment of nonphotochemical quenching, two effects consistent with the location of xanthophylls in photosystem II antenna, but also a decreased efficiency of photosynthetic electron transfer, photosensitivity, and lethality in soil. Biochemical analysis revealed that the nox mutant was specifically depleted in photosystem I function due to a severe deficiency in PsaA/B subunits. While the stationary level of psaA/B transcripts showed no major differences between genotypes, the stability of newly synthesized PsaA/B proteins was decreased and translation of psaA/B mRNA was impaired in nox with respect to wild-type plants. We conclude that xanthophylls, besides their role in photoprotection and LHC assembly, are also needed for photosystem I core translation and stability, thus making these compounds indispensable for autotrophic growth. PMID:23396829

  10. A Medicago truncatula Tobacco Retrotransposon Insertion Mutant Collection with Defects in Nodule Development and Symbiotic Nitrogen Fixation1[W][OA

    Science.gov (United States)

    Pislariu, Catalina I.; D. Murray, Jeremy; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; A. Benedito, Vagner; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E.; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S.; Chen, Rujin; Udvardi, Michael K.

    2012-01-01

    A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod−), 51 mutants with totally ineffective nodules (Nod+ Fix−), 17 mutants with partially ineffective nodules (Nod+ Fix+/−), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/− Fix−), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/− Fix+), and 11 supernodulating mutants (Nod++Fix+/−). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN’T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod− lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging. PMID:22679222

  11. Ultrastructure of a hexagonal array in exosporium of a highly sporogenic mutant of Clostridium botulinum type A revealed by electron microscopy using optical diffraction and filtration.

    Science.gov (United States)

    Masuda, K; Kawata, T; Takumi, K; Kinouchi, T

    1980-01-01

    The ultrastructure of a hexagonal array in the exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A strain 190L was studied by electron microscopy of negatively stained exosporium fragments using optical diffraction and filtration. The exosporium was composed of three or more lamellae showing and equilateral, hexagonal periodicity. Images of the single exosporium layer from which the noise had been filtered optically revealed that the hexagonally arranged, morphological unit of the exosporium was composed of three globular subunits about 2.1 nm in diameter which were arranged at the vertices of an equilateral triangle with sides of about 2.4 nm. The morphological units were arranged with a spacing of about 4.5 nm. the adjacent globular subunits appeared to be interconnected by delicate linkers.

  12. Two domain-disrupted hda6 alleles have opposite epigenetic effects on transgenes and some endogenous targets

    KAUST Repository

    Zhang, ShouDong; Zhan, Xiangqiang; Xu, Xiaoming; Cui, Peng; Zhu, Jian-Kang; Xia, Yiji; Xiong, Liming

    2015-01-01

    HDA6 is a RPD3-like histone deacetylase. In Arabidopsis, it mediates transgene and some endogenous target transcriptional gene silencing (TGS) via histone deacetylation and DNA methylation. Here, we characterized two hda6 mutant alleles that were recovered as second-site suppressors of the DNA demethylation mutant ros1–1. Although both alleles derepressed 35S::NPTII and RD29A::LUC in the ros1–1 background, they had distinct effects on the expression of these two transgenes. In accordance to expression profiles of two transgenes, the alleles have distinct opposite methylation profiles on two reporter gene promoters. Furthermore, both alleles could interact in vitro and in vivo with the DNA methyltransferase1 with differential interactive strength and patterns. Although these alleles accumulated different levels of repressive/active histone marks, DNA methylation but not histone modifications in the two transgene promoters was found to correlate with the level of derepression of the reporter genes between the two had6 alleles. Our study reveals that mutations in different domains of HDA6 convey different epigenetic status that in turn controls the expression of the transgenes as well as some endogenous loci.

  13. Two domain-disrupted hda6 alleles have opposite epigenetic effects on transgenes and some endogenous targets

    KAUST Repository

    Zhang, ShouDong

    2015-12-15

    HDA6 is a RPD3-like histone deacetylase. In Arabidopsis, it mediates transgene and some endogenous target transcriptional gene silencing (TGS) via histone deacetylation and DNA methylation. Here, we characterized two hda6 mutant alleles that were recovered as second-site suppressors of the DNA demethylation mutant ros1–1. Although both alleles derepressed 35S::NPTII and RD29A::LUC in the ros1–1 background, they had distinct effects on the expression of these two transgenes. In accordance to expression profiles of two transgenes, the alleles have distinct opposite methylation profiles on two reporter gene promoters. Furthermore, both alleles could interact in vitro and in vivo with the DNA methyltransferase1 with differential interactive strength and patterns. Although these alleles accumulated different levels of repressive/active histone marks, DNA methylation but not histone modifications in the two transgene promoters was found to correlate with the level of derepression of the reporter genes between the two had6 alleles. Our study reveals that mutations in different domains of HDA6 convey different epigenetic status that in turn controls the expression of the transgenes as well as some endogenous loci.

  14. Single-step selection of drug resistant Acinetobacter baylyi ADP1 mutants reveals a functional redundancy in the recruitment of multidrug efflux systems.

    Directory of Open Access Journals (Sweden)

    Anthony J Brzoska

    Full Text Available Members of the genus Acinetobacter have been the focus recent attention due to both their clinical significance and application to molecular biology. The soil commensal bacterium Acinetobacter baylyi ADP1 has been proposed as a model system for molecular and genetic studies, whereas in a clinical environment, Acinetobacter spp. are of increasing importance due to their propensity to cause serious and intractable systemic infections. Clinically, a major factor in the success of Acinetobacter spp. as opportunistic pathogens can be attributed to their ability to rapidly evolve resistance to common antimicrobial compounds. Whole genome sequencing of clinical and environmental Acinetobacter spp. isolates has revealed the presence of numerous multidrug transporters within the core and accessory genomes, suggesting that efflux is an important host defense response in this genus. In this work, we used the drug-susceptible organism A. baylyi ADP1 as a model for studies into the evolution of efflux mediated resistance in genus Acinetobacter, due to the high level of conservation of efflux determinants across four diverse Acinetobacter strains, including clinical isolates. A single exposure of therapeutic concentrations of chloramphenicol to populations of A. baylyi ADP1 cells produced five individual colonies displaying multidrug resistance. The major facilitator superfamily pump craA was upregulated in one mutant strain, whereas the resistance nodulation division pump adeJ was upregulated in the remaining four. Within the adeJ upregulated population, two different levels of adeJ mRNA transcription were observed, suggesting at least three separate mutations were selected after single-step exposure to chloramphenicol. In the craA upregulated strain, a T to G substitution 12 nt upstream of the craA translation initiation codon was observed. Subsequent mRNA stability analyses using this strain revealed that the half-life of mutant craA mRNA was significantly

  15. The goya mouse mutant reveals distinct newly identified roles for MAP3K1 in the development and survival of cochlear sensory hair cells

    Directory of Open Access Journals (Sweden)

    Andrew Parker

    2015-12-01

    Full Text Available Mitogen-activated protein kinase, MAP3K1, plays an important role in a number of cellular processes, including epithelial migration during eye organogenesis. In addition, studies in keratinocytes indicate that MAP3K1 signalling through JNK is important for actin stress fibre formation and cell migration. However, MAP3K1 can also act independently of JNK in the regulation of cell proliferation and apoptosis. We have identified a mouse mutant, goya, which exhibits the eyes-open-at-birth and microphthalmia phenotypes. In addition, these mice also have hearing loss. The goya mice carry a splice site mutation in the Map3k1 gene. We show that goya and kinase-deficient Map3k1 homozygotes initially develop supernumerary cochlear outer hair cells (OHCs that subsequently degenerate, and a progressive profound hearing loss is observed by 9 weeks of age. Heterozygote mice also develop supernumerary OHCs, but no cellular degeneration or hearing loss is observed. MAP3K1 is expressed in a number of inner-ear cell types, including outer and inner hair cells, stria vascularis and spiral ganglion. Investigation of targets downstream of MAP3K1 identified an increase in p38 phosphorylation (Thr180/Tyr182 in multiple cochlear tissues. We also show that the extra OHCs do not arise from aberrant control of proliferation via p27KIP1. The identification of the goya mutant reveals a signalling molecule involved with hair-cell development and survival. Mammalian hair cells do not have the ability to regenerate after damage, which can lead to irreversible sensorineural hearing loss. Given the observed goya phenotype, and the many diverse cellular processes that MAP3K1 is known to act upon, further investigation of this model might help to elaborate upon the mechanisms underlying sensory hair cell specification, and pathways important for their survival. In addition, MAP3K1 is revealed as a new candidate gene for human sensorineural hearing loss.

  16. A detailed clinical and molecular survey of subjects with nonsyndromic USH2A retinopathy reveals an allelic hierarchy of disease-causing variants

    Science.gov (United States)

    Lenassi, Eva; Vincent, Ajoy; Li, Zheng; Saihan, Zubin; Coffey, Alison J; Steele-Stallard, Heather B; Moore, Anthony T; Steel, Karen P; Luxon, Linda M; Héon, Elise; Bitner-Glindzicz, Maria; Webster, Andrew R

    2015-01-01

    Defects in USH2A cause both isolated retinal disease and Usher syndrome (ie, retinal disease and deafness). To gain insights into isolated/nonsyndromic USH2A retinopathy, we screened USH2A in 186 probands with recessive retinal disease and no hearing complaint in childhood (discovery cohort) and in 84 probands with recessive retinal disease (replication cohort). Detailed phenotyping, including retinal imaging and audiological assessment, was performed in individuals with two likely disease-causing USH2A variants. Further genetic testing, including screening for a deep-intronic disease-causing variant and large deletions/duplications, was performed in those with one likely disease-causing change. Overall, 23 of 186 probands (discovery cohort) were found to harbour two likely disease-causing variants in USH2A. Some of these variants were predominantly associated with nonsyndromic retinal degeneration (‘retinal disease-specific'); these included the common c.2276 G>T, p.(Cys759Phe) mutation and five additional variants: c.2802 T>G, p.(Cys934Trp); c.10073 G>A, p.(Cys3358Tyr); c.11156 G>A, p.(Arg3719His); c.12295-3 T>A; and c.12575 G>A, p.(Arg4192His). An allelic hierarchy was observed in the discovery cohort and confirmed in the replication cohort. In nonsyndromic USH2A disease, retinopathy was consistent with retinitis pigmentosa and the audiological phenotype was variable. USH2A retinopathy is a common cause of nonsyndromic recessive retinal degeneration and has a different mutational spectrum to that observed in Usher syndrome. The following model is proposed: the presence of at least one ‘retinal disease-specific' USH2A allele in a patient with USH2A-related disease results in the preservation of normal hearing. Careful genotype–phenotype studies such as this will become increasingly important, especially now that high-throughput sequencing is widely used in the clinical setting. PMID:25649381

  17. CYP3A4 allelic variants with amino acid substitutions in exons 7 and 12: evidence for an allelic variant with altered catalytic activity.

    Science.gov (United States)

    Sata, F; Sapone, A; Elizondo, G; Stocker, P; Miller, V P; Zheng, W; Raunio, H; Crespi, C L; Gonzalez, F J

    2000-01-01

    To determine the existence of mutant and variant CgammaP3A4 alleles in three racial groups and to assess functions of the variant alleles by complementary deoxyribonucleic acid (cDNA) expression. A bacterial artificial chromosome that contains the complete CgammaP3A4 gene was isolated and the exons and surrounding introns were directly sequenced to develop primers to polymerase chain reaction (PCR) amplify and sequence the gene from lymphocyte DNA. DNA samples from Chinese, black, and white subjects were screened. Mutating the affected amino acid in the wild-type cDNA and expressing the variant enzyme with use of the baculovirus system was used to functionally evaluate the variant allele having a missense mutation. To investigate the existence of mutant and variant CgammaP3A4 alleles in humans, all 13 exons and the 5'-flanking region of the human CgammaP3A4 gene in three racial groups were sequenced and four alleles were identified. An A-->G point mutation in the 5'-flanking region of the human CgammaP3A4 gene, designated CgammaP3A4*1B, was found in the three different racial groups. The frequency of this allele in a white population was 4.2%, whereas it was 66.7% in black subjects. The CgammaP3A4*1B allele was not found in Chinese subjects. A second variant allele, designated CgammaP3A4*2, having a Ser222Pro change, was found at a frequency of 2.7% in the white population and was absent in the black subjects and Chinese subjects analyzed. Baculovirus-directed cDNA expression revealed that the CYP3A4*2 P450 had a lower intrinsic clearance for the CYP3A4 substrate nifedipine compared with the wild-type enzyme but was not significantly different from the wild-type enzyme for testosterone 6beta-hydroxylation. Another rare allele, designated CgammaP3A4*3, was found in a single Chinese subject who had a Met445Thr change in the conserved heme-binding region of the P450. These are the first examples of potential function polymorphisms resulting from missense mutations in

  18. Somatic mutations, allele loss, and DNA methylation of the Cub and Sushi Multiple Domains 1 (CSMD1 gene reveals association with early age of diagnosis in colorectal cancer patients.

    Directory of Open Access Journals (Sweden)

    Austin Y Shull

    Full Text Available The Cub and Sushi Multiple Domains 1 (CSMD1 gene, located on the short arm of chromosome 8, codes for a type I transmembrane protein whose function is currently unknown. CSMD1 expression is frequently lost in many epithelial cancers. Our goal was to characterize the relationships between CSMD1 somatic mutations, allele imbalance, DNA methylation, and the clinical characteristics in colorectal cancer patients.We sequenced the CSMD1 coding regions in 54 colorectal tumors using the 454FLX pyrosequencing platform to interrogate 72 amplicons covering the entire coding sequence. We used heterozygous SNP allele ratios at multiple CSMD1 loci to determine allelic balance and infer loss of heterozygosity. Finally, we performed methylation-specific PCR on 76 colorectal tumors to determine DNA methylation status for CSMD1 and known methylation targets ALX4, RUNX3, NEUROG1, and CDKN2A.Using 454FLX sequencing and confirming with Sanger sequencing, 16 CSMD1 somatic mutations were identified in 6 of the 54 colorectal tumors (11%. The nonsynonymous to synonymous mutation ratio of the 16 somatic mutations was 15:1, a ratio significantly higher than the expected 2:1 ratio (p = 0.014. This ratio indicates a presence of positive selection for mutations in the CSMD1 protein sequence. CSMD1 allelic imbalance was present in 19 of 37 informative cases (56%. Patients with allelic imbalance and CSMD1 mutations were significantly younger (average age, 41 years than those without somatic mutations (average age, 68 years. The majority of tumors were methylated at one or more CpG loci within the CSMD1 coding sequence, and CSMD1 methylation significantly correlated with two known methylation targets ALX4 and RUNX3. C:G>T:A substitutions were significantly overrepresented (47%, suggesting extensive cytosine methylation predisposing to somatic mutations.Deep amplicon sequencing and methylation-specific PCR reveal that CSMD1 alterations can correlate with earlier clinical

  19. Study on the Wx Allele Gene Sequences of Two Low Amylose Content Mutants of Oryza indica%2个籼稻低直链淀粉突变体Wx等位基因序列的研究

    Institute of Scientific and Technical Information of China (English)

    郭涛; 韩诗曼; 夏斌; 王慧; 刘永柱; 张建国; 陈志强

    2011-01-01

    根据粳型水稻Wx基因全序列设计引物,扩增2个空间诱变低直链淀粉突变体XLA-1和XLA-2的Wx等位基因.序列分析结果表明:XLA-1、XLA-2与原种籼小占在Wx基因DNA序列上存在较多碱基差异,这种差异以碱基改变为主;XLA-1、XLA-2在第10外显子(+1 208 bp)处存在一个单核苷酸突变(籼小占为碱基T,突变体为碱基C),编码子由TCT突变为CCT,导致丝氨酸突变成脯氨酸,氨基酸的改变可能改变了Wx蛋白的空间结构,致使它不能充分结合在淀粉颗粒上,进而导致直链淀粉含量下降.本研究初步证明在2个籼稻突变体中存在Wx的复等位基因影响直链淀粉含量.%Based on the Wx gene sequence of japonica rice, the Wx gene sequences of the two low-amy-lose mutants XLA-1 and XLA-2 of Oryza indica were detected by PCR and sequencing analysis. The main results showed that: There were many mutant sites among XLA-1, XLA- 2 and Xianxiaozhan (the wild type) , most of them were base change. There was a sigle nucleotide polymorphisms(SNP) in the 10th exon( +1 208 bp) of XLA-1 and XLA-2(Xianxiaozhan for the T, mutant for the C), codon TCT changed into CCT, which resulted in the substitution of a proline residue for serine. The substitution could alter the spatial structure of Wx protein, which may not be fully integrated on the starch granules, leading to the decreased of amylose content. The preliminary results indicated that the existence of Wx allelles affected amylose content in the two mutants.

  20. Diguanylate cyclase null mutant reveals that C-Di-GMP pathway regulates the motility and adherence of the extremophile bacterium Acidithiobacillus caldus.

    Directory of Open Access Journals (Sweden)

    Matías Castro

    Full Text Available An understanding of biofilm formation is relevant to the design of biological strategies to improve the efficiency of the bioleaching process and to prevent environmental damages caused by acid mine/rock drainage. For this reason, our laboratory is focused on the characterization of the molecular mechanisms involved in biofilm formation in different biomining bacteria. In many bacteria, the intracellular levels of c-di-GMP molecules regulate the transition from the motile planktonic state to sessile community-based behaviors, such as biofilm development, through different kinds of effectors. Thus, we recently started a study of the c-di-GMP pathway in several biomining bacteria including Acidithiobacillus caldus. C-di-GMP molecules are synthesized by diguanylate cyclases (DGCs and degraded by phosphodiesterases (PDEs. We previously reported the existence of intermediates involved in c-di-GMP pathway from different Acidithiobacillus species. Here, we report our work related to At. caldus ATCC 51756. We identified several putative-ORFs encoding DGC and PDE and effector proteins. By using total RNA extracted from At. caldus cells and RT-PCR, we demonstrated that these genes are expressed. We also demonstrated the presence of c-di-GMP by mass spectrometry and showed that genes for several of the DGC enzymes were functional by heterologous genetic complementation in Salmonella enterica serovar Typhimurium mutants. Moreover, we developed a DGC defective mutant strain (Δc1319 that strongly indicated that the c-di-GMP pathway regulates the swarming motility and adherence to sulfur surfaces by At. caldus. Together, our results revealed that At. caldus possesses a functional c-di-GMP pathway which could be significant for ores colonization during the bioleaching process.

  1. Crystallographic Analysis Reveals a Novel Second Binding Site for Trimethoprim in Active Site Double Mutants of Human Dihydrofolate Reductase†,‡

    Science.gov (United States)

    Cody, Vivian; Pace, Jim; Piraino, Jennifer; Queener, Sherry F.

    2011-01-01

    In order to produce a more potent replacement for trimethoprim (TMP) used as a therapy for Pneumocystis pneumonia and targets dihydrofolate reductase from Pneumocystis jirovecii (pjDHFR), it is necessary to understand the determinants of potency and selectivity against DHFR from the mammalian host and fungal pathogen cells. To this end, active site residues in human (h)DHFR were replaced with those from pjDHFR. Structural data are reported for two complexes of TMP with the double mutants Gln35Ser/Asn64Phe (Q35S/N64F) and Gln35Lys/Asn64Phe (Q35K/N64F) of hDHFR that unexpectedly show evidence for the binding of two molecules of TMP: one molecule that binds in the normal folate binding site and the second molecule that binds in a novel subpocket site such that the mutated residue Phe64 is involved in van der Waals contacts to the trimethoxyphenyl ring of the second TMP molecule. Kinetic data for the binding of TMP to hDHFR and pjDHFR reveal an 84-fold selectivity of TMP against pjDHFR (Ki 49 nM) compared to hDHFR (Ki 4093 nM). Two mutants that contain one substitution from pj- and one from the closely related Pneumocystis carinii DHFR (pcDHFR) (Q35K/N64F and Q35S/N64F) show Ki values of 593 and 617 nM, respectively; these Ki values are well above both the Ki for pjDHFR and are similar to pcDHFR (Q35K/N64F) and Q35S/N64F) (305 nM). These results suggest that active site residues 35 and 64 play key roles in determining selectivity for pneumocystis DHFR, but that other residues contribute to the unique binding of inhibitors to these enzymes. PMID:21684339

  2. Synapsis-Defective Mutants Reveal a Correlation Between Chromosome Conformation and the Mode of Double-Strand Break Repair During Caenorhabditis elegans Meiosis

    OpenAIRE

    Smolikov, Sarit; Eizinger, Andreas; Hurlburt, Allison; Rogers, Eric; Villeneuve, Anne M.; Colaiácovo, Mónica P.

    2007-01-01

    SYP-3 is a new structural component of the synaptonemal complex (SC) required for the regulation of chromosome synapsis. Both chromosome morphogenesis and nuclear organization are altered throughout the germlines of syp-3 mutants. Here, our analysis of syp-3 mutants provides insights into the relationship between chromosome conformation and the repair of meiotic double-strand breaks (DSBs). Although crossover recombination is severely reduced in syp-3 mutants, the production of viable offspri...

  3. Identification of a Gravitropism-Deficient Mutant in Rice

    Directory of Open Access Journals (Sweden)

    He Yan

    2017-03-01

    Full Text Available A gravitropism-deficient mutant M96 was isolated from a mutant bank, generated by ethyl methane sulfonate (EMS mutagenesis of indica rice accession ZJ100. The mutant was characterized as prostrate growth at the beginning of germination, and the prostrate growth phenotype ran through the whole life duration. Tiller angle and tiller number of M96 increased significantly in comparison with the wild type. Tissue section observation analysis indicated that asymmetric stem growth around the second node occurred in M96. Genetic analysis and gene mapping showed that M96 was controlled by a single recessive nuclear gene, tentatively termed as gravitropism-deficient M96 (gdM96, which was mapped to a region of 506 kb flanked by markers RM5960 and InDel8 on the long arm of chromosome 11. Sequencing analysis of the open reading frames in this region revealed a nucleotide substitution from G to T in the third exon of LOC_Os11g29840. Additionally, real-time fluorescence quantitative PCR analysis showed that the expression level of LOC_Os11g29840 in the stems was much higher than in the roots and leaves in M96. Furthermore, the expression level was more than four times in M96 stem than in the wild type stem. Our results suggested that the mutant gene was likely a new allele to the reported gene LAZY1. Isolation of this new allele would facilitate the further characterization of LAZY1.

  4. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 2. Comparison of Various Mutants

    International Nuclear Information System (INIS)

    Balchiuniene, L.

    1995-01-01

    Spontaneous and gamma-induced mutability was compared in two groups of genetically unstable barley ear structure mutants - tweaky spike (tw) and branched ear (be). Instability in different loci causes different levels of spontaneous and gamma-induced mutability. A high spontaneous level of chlorophyll mutations is peculiar to be-ust mutants. It is suggested that the high level of induced chlorophyll mutations in allelic tw mutants is a result of better surviving of chlorophyll mutation carriers in the genotypical-physiological environment created by mutant tw alleles. (author). 6 refs., 2 tabs

  5. The goya mouse mutant reveals distinct newly identified roles for MAP3K1 in the development and survival of cochlear sensory hair cells.

    Science.gov (United States)

    Parker, Andrew; Cross, Sally H; Jackson, Ian J; Hardisty-Hughes, Rachel; Morse, Susan; Nicholson, George; Coghill, Emma; Bowl, Michael R; Brown, Steve D M

    2015-12-01

    Mitogen-activated protein kinase, MAP3K1, plays an important role in a number of cellular processes, including epithelial migration during eye organogenesis. In addition, studies in keratinocytes indicate that MAP3K1 signalling through JNK is important for actin stress fibre formation and cell migration. However, MAP3K1 can also act independently of JNK in the regulation of cell proliferation and apoptosis. We have identified a mouse mutant, goya, which exhibits the eyes-open-at-birth and microphthalmia phenotypes. In addition, these mice also have hearing loss. The goya mice carry a splice site mutation in the Map3k1 gene. We show that goya and kinase-deficient Map3k1 homozygotes initially develop supernumerary cochlear outer hair cells (OHCs) that subsequently degenerate, and a progressive profound hearing loss is observed by 9 weeks of age. Heterozygote mice also develop supernumerary OHCs, but no cellular degeneration or hearing loss is observed. MAP3K1 is expressed in a number of inner-ear cell types, including outer and inner hair cells, stria vascularis and spiral ganglion. Investigation of targets downstream of MAP3K1 identified an increase in p38 phosphorylation (Thr180/Tyr182) in multiple cochlear tissues. We also show that the extra OHCs do not arise from aberrant control of proliferation via p27KIP1. The identification of the goya mutant reveals a signalling molecule involved with hair-cell development and survival. Mammalian hair cells do not have the ability to regenerate after damage, which can lead to irreversible sensorineural hearing loss. Given the observed goya phenotype, and the many diverse cellular processes that MAP3K1 is known to act upon, further investigation of this model might help to elaborate upon the mechanisms underlying sensory hair cell specification, and pathways important for their survival. In addition, MAP3K1 is revealed as a new candidate gene for human sensorineural hearing loss. © 2015. Published by The Company of

  6. Dwarf mutant of rice variety Seratus Malam

    International Nuclear Information System (INIS)

    Mugiono, P. S.; Soemanggono, A.M.R.

    1989-01-01

    Full text: Seeds of 'Seratus Malam', a local tall upland variety with long panicles and high yield potential were irradiated with 10-50 krad gamma rays in 1983. From 50,000 M 2 plants, 130 semidwarf mutants and 1 dwarf mutant were selected. The dwarf mutant M-362 was obtained from the 10 krad treatment. The mutant shows about 50% reduction in plant height, but also in number of productive tillers. Thus the yield per plant is also significantly less. However, the mutant gene is not allelic to DGWG and therefore may be useful in cross breeding. (author)

  7. The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

    International Nuclear Information System (INIS)

    Ebisawa, Tatsuki; Yamamura, Akihiro; Kameda, Yasuhiro; Hayakawa, Kou; Nagata, Koji; Tanokura, Masaru

    2010-01-01

    The crystal structure of a monomeric mutant of Azami-Green (mAG) from G. fascicularis was determined at 2.2 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants

  8. Genome-wide identification and expression profiling reveal tissue-specific expression and differentially-regulated genes involved in gibberellin metabolism between Williams banana and its dwarf mutant.

    Science.gov (United States)

    Chen, Jingjing; Xie, Jianghui; Duan, Yajie; Hu, Huigang; Hu, Yulin; Li, Weiming

    2016-05-27

    Dwarfism is one of the most valuable traits in banana breeding because semi-dwarf cultivars show good resistance to damage by wind and rain. Moreover, these cultivars present advantages of convenient cultivation, management, and so on. We obtained a dwarf mutant '8818-1' through EMS (ethyl methane sulphonate) mutagenesis of Williams banana 8818 (Musa spp. AAA group). Our research have shown that gibberellins (GAs) content in 8818-1 false stems was significantly lower than that in its parent 8818 and the dwarf type of 8818-1 could be restored by application of exogenous GA3. Although GA exerts important impacts on the 8818-1 dwarf type, our understanding of the regulation of GA metabolism during banana dwarf mutant development remains limited. Genome-wide screening revealed 36 candidate GA metabolism genes were systematically identified for the first time; these genes included 3 MaCPS, 2 MaKS, 1 MaKO, 2 MaKAO, 10 MaGA20ox, 4 MaGA3ox, and 14 MaGA2ox genes. Phylogenetic tree and conserved protein domain analyses showed sequence conservation and divergence. GA metabolism genes exhibited tissue-specific expression patterns. Early GA biosynthesis genes were constitutively expressed but presented differential regulation in different tissues in Williams banana. GA oxidase family genes were mainly transcribed in young fruits, thus suggesting that young fruits were the most active tissue involved in GA metabolism, followed by leaves, bracts, and finally approximately mature fruits. Expression patterns between 8818 and 8818-1 revealed that MaGA20ox4, MaGA20ox5, and MaGA20ox7 of the MaGA20ox gene family and MaGA2ox7, MaGA2ox12, and MaGA2ox14 of the MaGA2ox gene family exhibited significant differential expression and high-expression levels in false stems. These genes are likely to be responsible for the regulation of GAs content in 8818-1 false stems. Overall, phylogenetic evolution, tissue specificity and differential expression analyses of GA metabolism genes can provide a

  9. In Vivo-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic penA Alleles That Confer Ceftriaxone Resistance in Neisseria gonorrhoeae

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    Leah R. Vincent

    2018-04-01

    Full Text Available Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2 variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cror clinical isolates (H041 and F89 into a Cros strain (FA19 by allelic exchange and showed that the resultant Cror mutants were significantly outcompeted by the Cros parent strain in vitro and in a murine infection model. Four Cror compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo. One of these compensatory mutants (LV41C displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnBG348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq analysis of FA19 penA41 acnBG348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cror gonococcal strains that increase metabolism to ameliorate their fitness deficit.

  10. Multiple antibiotic susceptibility of polyphosphate kinase mutants (ppk1 and ppk2 from Pseudomonas aeruginosa PAO1 as revealed by global phenotypic analysis

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    Javiera Ortiz-Severín

    2015-01-01

    Full Text Available BACKGROUND: Pseudomonas aeruginosa is known to be a multidrug resistant opportunistic pathogen. Particularly, P. aeruginosa PAO1 polyphosphate kinase mutant (ppk1 is deficient in motility, quorum sensing, biofilm formation and virulence FINDINGS: By using Phenotypic Microarrays (PM we analyzed near 2000 phenotypes of P. aeruginosa PAO1 polyP kinase mutants (ppk1 and ppk2. We found that both ppk mutants shared most of the phenotypic changes and interestingly many of them related to susceptibility toward numerous and different type of antibiotics such as Ciprofloxacin, Chloramphenicol and Rifampicin CONCLUSIONS: Combining the fact that ppk1 mutants have reduced virulence and are more susceptible to antibiotics, polyP synthesis and particularly PPK1, is a good target for the design of molecules with anti-virulence and anti-persistence properties.

  11. Synapsis-defective mutants reveal a correlation between chromosome conformation and the mode of double-strand break repair during Caenorhabditis elegans meiosis.

    Science.gov (United States)

    Smolikov, Sarit; Eizinger, Andreas; Hurlburt, Allison; Rogers, Eric; Villeneuve, Anne M; Colaiácovo, Mónica P

    2007-08-01

    SYP-3 is a new structural component of the synaptonemal complex (SC) required for the regulation of chromosome synapsis. Both chromosome morphogenesis and nuclear organization are altered throughout the germlines of syp-3 mutants. Here, our analysis of syp-3 mutants provides insights into the relationship between chromosome conformation and the repair of meiotic double-strand breaks (DSBs). Although crossover recombination is severely reduced in syp-3 mutants, the production of viable offspring accompanied by the disappearance of RAD-51 foci suggests that DSBs are being repaired in these synapsis-defective mutants. Our studies indicate that once interhomolog recombination is impaired, both intersister recombination and nonhomologous end-joining pathways may contribute to repair during germline meiosis. Moreover, our studies suggest that the conformation of chromosomes may influence the mode of DSB repair employed during meiosis.

  12. Transcriptional analysis of the HeT-A retrotransposon in mutant and wild type stocks reveals high sequence variability at Drosophila telomeres and other unusual features

    Directory of Open Access Journals (Sweden)

    Piñeyro David

    2011-11-01

    Full Text Available Abstract Background Telomere replication in Drosophila depends on the transposition of a domesticated retroelement, the HeT-A retrotransposon. The sequence of the HeT-A retrotransposon changes rapidly resulting in differentiated subfamilies. This pattern of sequence change contrasts with the essential function with which the HeT-A is entrusted and brings about questions concerning the extent of sequence variability, the telomere contribution of different subfamilies, and whether wild type and mutant Drosophila stocks show different HeT-A scenarios. Results A detailed study on the variability of HeT-A reveals that both the level of variability and the number of subfamilies are higher than previously reported. Comparisons between GIII, a strain with longer telomeres, and its parental strain Oregon-R indicate that both strains have the same set of HeT-A subfamilies. Finally, the presence of a highly conserved splicing pattern only in its antisense transcripts indicates a putative regulatory, functional or structural role for the HeT-A RNA. Interestingly, our results also suggest that most HeT-A copies are actively expressed regardless of which telomere and where in the telomere they are located. Conclusions Our study demonstrates how the HeT-A sequence changes much faster than previously reported resulting in at least nine different subfamilies most of which could actively contribute to telomere extension in Drosophila. Interestingly, the only significant difference observed between Oregon-R and GIII resides in the nature and proportion of the antisense transcripts, suggesting a possible mechanism that would in part explain the longer telomeres of the GIII stock.

  13. Saccharomyces cerevisiae mutants with enhanced induced mutation and altered mitotic gene conversion.

    Science.gov (United States)

    Ivanov, E L; Kovaltzova, S V; Korolev, V G

    1989-08-01

    We have developed a method to isolate yeast (Saccharomyces cerevisiae) mutants with enhanced induced mutagenesis based on nitrous acid-induced reversion of the ade2-42 allele. Six mutants have been isolated and designated him (high induced mutagenesis), and 4 of them were studied in more detail. The him mutants displayed enhanced reversion of the ade2-42 allele, either spontaneous or induced by nitrous acid, UV light, and the base analog 6-N-hydroxylaminopurine, but not by gamma-irradiation. It is worth noting that the him mutants turned out not to be sensitive to the lethal effects of the mutagens used. The enhancement in mutation induced by nitrous acid, UV light, and 6-N-hydroxylaminopurine has been confirmed in a forward-mutation assay (induction of mutations in the ADE1, ADE2 genes). The latter agent revealed the most apparent differences between the him mutants and the wild-type strain and was, therefore, chosen for the genetic analysis of mutants, him mutations analyzed behaved as a single Mendelian trait; complementation tests indicated 3 complementation groups (HIM1, HIM2, and HIM3), each containing 1 mutant allele. Uracil-DNA glycosylase activity was determined in crude cell extracts, and no significant differences between the wild-type and him strains were detected. Spontaneous mitotic gene conversion at the ADE2 locus is altered in him1 strains, either increased or decreased, depending on the particular heteroallelic combination. Genetic evidence strongly suggests him mutations to be involved in a process of mismatch correction of molecular heteroduplexes.

  14. Mutation in cpsf6/CFIm68 (Cleavage and Polyadenylation Specificity Factor Subunit 6 causes short 3'UTRs and disturbs gene expression in developing embryos, as revealed by an analysis of primordial germ cell migration using the medaka mutant naruto.

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    Takao Sasado

    Full Text Available Our previous studies analyzing medaka mutants defective in primordial germ cell (PGC migration identified cxcr4b and cxcr7, which are both receptors of the chemokine sdf1/cxcl12, as key regulators of PGC migration. Among PGC migration mutants, naruto (nar is unique in that the mutant phenotype includes gross morphological abnormalities of embryos, suggesting that the mutation affects a broader range of processes. A fine genetic linkage mapping and genome sequencing showed the nar gene encodes Cleavage and Polyadenylation Specificity Factor subunit 6 (CPSF6/CFIm68. CPSF6 is a component of the Cleavage Factor Im complex (CFIm which plays a key role in pre-mRNA 3'-cleavage and polyadenylation. 3'RACE of sdf1a/b and cxcr7 transcripts in the mutant embryos indicated shorter 3'UTRs with poly A additions occurring at more upstream positions than wild-type embryos, suggesting CPSF6 functions to prevent premature 3'UTR cleavage. In addition, expression of the coding region sequences of sdf1a/b in nar mutants was more anteriorly extended in somites than wild-type embryos, accounting for the abnormally extended distribution of PGCs in nar mutants. An expected consequence of shortening 3'UTR is the escape from the degradation mechanism mediated by microRNAs interacting with distal 3'UTR sequence. The abnormal expression pattern of sdf1a coding sequence may be at least partially accounted for by this mechanism. Given the pleiotropic effects of nar mutation, further analysis using the nar mutant will reveal processes in which CPSF6 plays essential regulatory roles in poly A site selection and involvement of 3'UTRs in posttranscriptional gene regulation in various genes in vivo.

  15. Mutation in cpsf6/CFIm68 (Cleavage and Polyadenylation Specificity Factor Subunit 6) causes short 3'UTRs and disturbs gene expression in developing embryos, as revealed by an analysis of primordial germ cell migration using the medaka mutant naruto.

    Science.gov (United States)

    Sasado, Takao; Kondoh, Hisato; Furutani-Seiki, Makoto; Naruse, Kiyoshi

    2017-01-01

    Our previous studies analyzing medaka mutants defective in primordial germ cell (PGC) migration identified cxcr4b and cxcr7, which are both receptors of the chemokine sdf1/cxcl12, as key regulators of PGC migration. Among PGC migration mutants, naruto (nar) is unique in that the mutant phenotype includes gross morphological abnormalities of embryos, suggesting that the mutation affects a broader range of processes. A fine genetic linkage mapping and genome sequencing showed the nar gene encodes Cleavage and Polyadenylation Specificity Factor subunit 6 (CPSF6/CFIm68). CPSF6 is a component of the Cleavage Factor Im complex (CFIm) which plays a key role in pre-mRNA 3'-cleavage and polyadenylation. 3'RACE of sdf1a/b and cxcr7 transcripts in the mutant embryos indicated shorter 3'UTRs with poly A additions occurring at more upstream positions than wild-type embryos, suggesting CPSF6 functions to prevent premature 3'UTR cleavage. In addition, expression of the coding region sequences of sdf1a/b in nar mutants was more anteriorly extended in somites than wild-type embryos, accounting for the abnormally extended distribution of PGCs in nar mutants. An expected consequence of shortening 3'UTR is the escape from the degradation mechanism mediated by microRNAs interacting with distal 3'UTR sequence. The abnormal expression pattern of sdf1a coding sequence may be at least partially accounted for by this mechanism. Given the pleiotropic effects of nar mutation, further analysis using the nar mutant will reveal processes in which CPSF6 plays essential regulatory roles in poly A site selection and involvement of 3'UTRs in posttranscriptional gene regulation in various genes in vivo.

  16. A Suppressor of the Menadione-Hypersensitive Phenotype of a Xanthomonas campestris pv. phaseoli oxyR Mutant Reveals a Novel Mechanism of Toxicity and the Protective Role of Alkyl Hydroperoxide Reductase

    Science.gov (United States)

    Vattanaviboon, Paiboon; Whangsuk, Wirongrong; Mongkolsuk, Skorn

    2003-01-01

    We isolated menadione-resistant mutants of Xanthomonas campestris pv. phaseoli oxyR (oxyRXp). The oxyRR2Xp mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to H2O2 and tert-butyl hydroperoxide. Analysis of enzymes involved in oxidative-stress protection in the oxyRR2Xp mutant revealed a >10-fold increase in AhpC and AhpF levels, while the levels of superoxide dismutase (SOD), catalase, and the organic hydroperoxide resistance protein (Ohr) were not significantly altered. Inactivation of ahpC in the oxyRR2Xp mutant resulted in increased sensitivity to menadione killing. Moreover, high levels of expression of cloned ahpC and ahpF in the oxyRXp mutant complemented the menadione hypersensitivity phenotype. High levels of other oxidant-scavenging enzymes such as catalase and SOD did not protect the cells from menadione toxicity. These data strongly suggest that the toxicity of superoxide generators could be mediated via organic peroxide production and that alkyl hydroperoxide reductase has an important novel function in the protection against the toxicity of these compounds in X. campestris. PMID:12591894

  17. Metabolic analysis of the increased adventitious rooting mutant of Artemisia annua reveals a role for the plant monoterpene borneol in adventitious root formation.

    Science.gov (United States)

    Tian, Na; Liu, Shuoqian; Li, Juan; Xu, Wenwen; Yuan, Lin; Huang, Jianan; Liu, Zhonghua

    2014-08-01

    Adventitious root (AR) formation is a critical process for plant clonal propagation. The role of plant secondary metabolites in AR formation is still poorly understood. Chemical and physical mutagenesis in combination with somatic variation were performed on Artemisia annua in order to obtain a mutant with changes in adventitious rooting and composition of plant secondary metabolites. Metabolic and morphological analyses of the iar (increased adventitious rooting) mutant coupled with in vitro assays were used to elucidate the relationship between plant secondary metabolites and AR formation. The only detected differences between the iar mutant and wild-type were rooting capacity and borneol/camphor content. Consistent with this, treatment with borneol in vitro promoted adventitious rooting in wild-type. The enhanced rooting did not continue upon removal of borneol. The iar mutant displayed no significant differences in AR formation upon treatment with camphor. Together, our results suggest that borneol promotes adventitious rooting whereas camphor has no effect on AR formation. © 2013 Scandinavian Plant Physiology Society.

  18. High-throughput sequencing of Campylobacter jejuni insertion mutant libraries reveals mapA as a fitness factor for chicken colonization.

    Science.gov (United States)

    Johnson, Jeremiah G; Livny, Jonathan; Dirita, Victor J

    2014-06-01

    Campylobacter jejuni is a leading cause of gastrointestinal infections worldwide, due primarily to its ability to asymptomatically colonize the gastrointestinal tracts of agriculturally relevant animals, including chickens. Infection often occurs following consumption of meat that was contaminated by C. jejuni during harvest. Because of this, much interest lies in understanding the mechanisms that allow C. jejuni to colonize the chicken gastrointestinal tract. To address this, we generated a C. jejuni transposon mutant library that is amenable to insertion sequencing and introduced this mutant pool into day-of-hatch chicks. Following deep sequencing of C. jejuni mutants in the cecal outputs, several novel factors required for efficient colonization of the chicken gastrointestinal tract were identified, including the predicted outer membrane protein MapA. A mutant strain lacking mapA was constructed and found to be significantly reduced for chicken colonization in both competitive infections and monoinfections. Further, we found that mapA is required for in vitro competition with wild-type C. jejuni but is dispensable for growth in monoculture.

  19. pH Dependency of sclerotial development and pathogenicity revealed by using genetically defined oxalate-minus mutants of Sclerotinia sclerotiorum

    Science.gov (United States)

    The devastating plant pathogen Sclerotinia sclerotiorum produces copious (up to 50mM) amounts of oxalic acid, which, for over a quarter century, has been claimed as the pathogenicity determinant based on UV-induced mutants that concomitantly lost oxalate production and pathogenicity. Such a claim wa...

  20. A study of Huntington disease-like syndromes in black South African patients reveals a single SCA2 mutation and a unique distribution of normal alleles across five repeat loci.

    Science.gov (United States)

    Baine, Fiona K; Peerbhai, Nabeelah; Krause, Amanda

    2018-07-15

    Huntington disease (HD) is a progressive neurodegenerative disease, characterised by a triad of movement disorder, emotional and behavioural disturbances and cognitive impairment. The underlying cause is an expanded CAG repeat in the huntingtin gene. For a small proportion of patients presenting with HD-like symptoms, the mutation in this gene is not identified and they are said to have a HD "phenocopy". South Africa has the highest number of recorded cases of an African-specific phenocopy, Huntington disease-like 2 (HDL2), caused by a repeat expansion in the junctophilin-3 gene. However, a significant proportion of black patients with clinical symptoms suggestive of HD still test negative for HD and HDL2. This study thus aimed to investigate five other loci associated with HD phenocopy syndromes - ATN1, ATXN2, ATXN7, TBP and C9orf72. In a sample of patients in whom HD and HDL2 had been excluded, a single expansion was identified in the ATXN2 gene, confirming a diagnosis of Spinocerebellar ataxia 2. The results indicate that common repeat expansion disorders do not contribute significantly to the HD-like phenotype in black South African patients. Importantly, allele sizing reveals unique distributions of normal repeat lengths across the associated loci in the African population studied. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

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    Andreia Michelle Smith-Moritz

    2015-08-01

    Full Text Available The CELLULOSE SYNTHASE-LIKE F6 (CslF6 gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG, a cell wall polysaccharide that is hypothesized to be a tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to test the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of three day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell was of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.

  2. A quadruple mutant of Arabidopsis reveals a β-carotene hydroxylation activity for LUT1/CYP97C1 and a regulatory role of xanthophylls on determination of the PSI/PSII ratio.

    Science.gov (United States)

    Fiore, Alessia; Dall'Osto, Luca; Cazzaniga, Stefano; Diretto, Gianfranco; Giuliano, Giovanni; Bassi, Roberto

    2012-04-18

    Xanthophylls are oxygenated carotenoids playing an essential role as structural components of the photosynthetic apparatus. Xanthophylls contribute to the assembly and stability of light-harvesting complex, to light absorbance and to photoprotection. The first step in xanthophyll biosynthesis from α- and β-carotene is the hydroxylation of ε- and β-rings, performed by both non-heme iron oxygenases (CHY1, CHY2) and P450 cytochromes (LUT1/CYP97C1, LUT5/CYP97A3). The Arabidopsis triple chy1chy2lut5 mutant is almost completely depleted in β-xanthophylls. Here we report on the quadruple chy1chy2lut2lut5 mutant, additionally carrying the lut2 mutation (affecting lycopene ε-cyclase). This genotype lacks lutein and yet it shows a compensatory increase in β-xanthophylls with respect to chy1chy2lut5 mutant. Mutant plants show an even stronger photosensitivity than chy1chy2lut5, a complete lack of qE, the rapidly reversible component of non-photochemical quenching, and a peculiar organization of the pigment binding complexes into thylakoids. Biochemical analysis reveals that the chy1chy2lut2lut5 mutant is depleted in Lhcb subunits and is specifically affected in Photosystem I function, showing a deficiency in PSI-LHCI supercomplexes. Moreover, by analyzing a series of single, double, triple and quadruple Arabidopsis mutants in xanthophyll biosynthesis, we show a hitherto undescribed correlation between xanthophyll levels and the PSI-PSII ratio. The decrease in the xanthophyll/carotenoid ratio causes a proportional decrease in the LHCII and PSI core levels with respect to PSII. The physiological and biochemical phenotype of the chy1chy2lut2lut5 mutant shows that (i) LUT1/CYP97C1 protein reveals a major β-carotene hydroxylase activity in vivo when depleted in its preferred substrate α-carotene; (ii) xanthophylls are needed for normal level of Photosystem I and LHCII accumulation.

  3. A quadruple mutant of Arabidopsis reveals a β-carotene hydroxylation activity for LUT1/CYP97C1 and a regulatory role of xanthophylls on determination of the PSI/PSII ratio

    Directory of Open Access Journals (Sweden)

    Fiore Alessia

    2012-04-01

    Full Text Available Abstract Background Xanthophylls are oxygenated carotenoids playing an essential role as structural components of the photosynthetic apparatus. Xanthophylls contribute to the assembly and stability of light-harvesting complex, to light absorbance and to photoprotection. The first step in xanthophyll biosynthesis from α- and β-carotene is the hydroxylation of ε- and β-rings, performed by both non-heme iron oxygenases (CHY1, CHY2 and P450 cytochromes (LUT1/CYP97C1, LUT5/CYP97A3. The Arabidopsis triple chy1chy2lut5 mutant is almost completely depleted in β-xanthophylls. Results Here we report on the quadruple chy1chy2lut2lut5 mutant, additionally carrying the lut2 mutation (affecting lycopene ε-cyclase. This genotype lacks lutein and yet it shows a compensatory increase in β-xanthophylls with respect to chy1chy2lut5 mutant. Mutant plants show an even stronger photosensitivity than chy1chy2lut5, a complete lack of qE, the rapidly reversible component of non-photochemical quenching, and a peculiar organization of the pigment binding complexes into thylakoids. Biochemical analysis reveals that the chy1chy2lut2lut5 mutant is depleted in Lhcb subunits and is specifically affected in Photosystem I function, showing a deficiency in PSI-LHCI supercomplexes. Moreover, by analyzing a series of single, double, triple and quadruple Arabidopsis mutants in xanthophyll biosynthesis, we show a hitherto undescribed correlation between xanthophyll levels and the PSI-PSII ratio. The decrease in the xanthophyll/carotenoid ratio causes a proportional decrease in the LHCII and PSI core levels with respect to PSII. Conclusions The physiological and biochemical phenotype of the chy1chy2lut2lut5 mutant shows that (i LUT1/CYP97C1 protein reveals a major β-carotene hydroxylase activity in vivo when depleted in its preferred substrate α-carotene; (ii xanthophylls are needed for normal level of Photosystem I and LHCII accumulation.

  4. Analysis of a lin-42/period Null Allele Implicates All Three Isoforms in Regulation of Caenorhabditis elegans Molting and Developmental Timing

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    Theresa L. B. Edelman

    2016-12-01

    Full Text Available The Caenorhabditis elegans heterochronic gene pathway regulates the relative timing of events during postembryonic development. lin-42, the worm homolog of the circadian clock gene, period, is a critical element of this pathway. lin-42 function has been defined by a set of hypomorphic alleles that cause precocious phenotypes, in which later developmental events, such as the terminal differentiation of hypodermal cells, occur too early. A subset of alleles also reveals a significant role for lin-42 in molting; larval stages are lengthened and ecdysis often fails in these mutant animals. lin-42 is a complex locus, encoding overlapping and nonoverlapping isoforms. Although existing alleles that affect subsets of isoforms have illuminated important and distinct roles for this gene in developmental timing, molting, and the decision to enter the alternative dauer state, it is essential to have a null allele to understand all of the roles of lin-42 and its individual isoforms. To remedy this problem and discover the null phenotype, we engineered an allele that deletes the entire lin-42 protein-coding region. lin-42 null mutants are homozygously viable, but have more severe phenotypes than observed in previously characterized hypomorphic alleles. We also provide additional evidence for this conclusion by using the null allele as a base for reintroducing different isoforms, showing that each isoform can provide heterochronic and molting pathway activities. Transcript levels of the nonoverlapping isoforms appear to be under coordinate temporal regulation, despite being driven by independent promoters. The lin-42 null allele will continue to be an important tool for dissecting the functions of lin-42 in molting and developmental timing.

  5. Diminished levels of allelic losses by homologous recombination in radiation-hypersensitive cells

    International Nuclear Information System (INIS)

    Tatsumi, K.; Abe, M.; Hoki, Y.; Kubo, E.; Muto, M.; Araki, R.; Sato, K.

    2003-01-01

    Mitotic recombination (MR) due to somatic crossing-over is a predominant mechanism for allelic losses in mammalian cells either spontaneous or radiation-induced. A selectable mutation assay accompanying real-time detection PCR was developed to analyze the second step in loss-of-function mutations employing a human lympho-blastoid cell line derived from an obligate heterozygote of 2,8-dihydroxyadenine urolithiasis, adenine phosphoribosyltransferase (APRT) deficiency with a nonsense mutation at exon 3 of the gene. 68 % of spontaneously arising 2,6-diaminopurine resistance (DAP r ) mutant clones were associated with loss of heterozygosity (LOH), while 92 % of 2 Gy gamma-ray induced mutant clones were so associated. Investigation of gene dosage revealed that about one half of the spontaneously arising mutant clones and two-thirds of those induced by gamma-rays showed reduction to homozygosity of the constitutionally inactivated APRT allele. In an ataxia telangiectasia (AT) cell subline in which a new inactivation mutation had been introduced into one APRT allele by ICR-191, MR rarely occurred and exclusively deletions predominated in both spontaneous and X-ray induced DAP r mutants with LOH. A similar assay system was also developed with C3H mouse FM3A mammary tumor cells, SR-1, carrying a C .T transition at exon 5 of an APRT allele. In an XRCC7 (DNA-PKcs) deficient subline of SR-1, SX9 , spontaneous mutation frequencies for the Aprt locus (8AA r ) was 10 -3 , which was about 10 times higher than that in parental SR-1 cells. Mutation frequencies induced by X-rays comparably increased in a dose-dependent manner for the Aprt locus in both cell lines. Against our expectation, the lack of an NHEJ pathway of DNA double strand break repair resulted in a lower proportion (11.1 %) of MR with deletions (77.8 %) as the molecular cause for 8AA r mutations following X-irradiation, while virtually all of X-ray induced 8AA r mutant clones were MR in the control SR-1 cells. Factors

  6. A knock-in/knock-out mouse model of HSPB8-associated distal hereditary motor neuropathy and myopathy reveals toxic gain-of-function of mutant Hspb8.

    Science.gov (United States)

    Bouhy, Delphine; Juneja, Manisha; Katona, Istvan; Holmgren, Anne; Asselbergh, Bob; De Winter, Vicky; Hochepied, Tino; Goossens, Steven; Haigh, Jody J; Libert, Claude; Ceuterick-de Groote, Chantal; Irobi, Joy; Weis, Joachim; Timmerman, Vincent

    2018-01-01

    Mutations in the small heat shock protein B8 gene (HSPB8/HSP22) have been associated with distal hereditary motor neuropathy, Charcot-Marie-Tooth disease, and recently distal myopathy. It is so far not clear how mutant HSPB8 induces the neuronal and muscular phenotypes and if a common pathogenesis lies behind these diseases. Growing evidence points towards a role of HSPB8 in chaperone-associated autophagy, which has been shown to be a determinant for the clearance of poly-glutamine aggregates in neurodegenerative diseases but also for the maintenance of skeletal muscle myofibrils. To test this hypothesis and better dissect the pathomechanism of mutant HSPB8, we generated a new transgenic mouse model leading to the expression of the mutant protein (knock-in lines) or the loss-of-function (functional knock-out lines) of the endogenous protein Hspb8. While the homozygous knock-in mice developed motor deficits associated with degeneration of peripheral nerves and severe muscle atrophy corroborating patient data, homozygous knock-out mice had locomotor performances equivalent to those of wild-type animals. The distal skeletal muscles of the post-symptomatic homozygous knock-in displayed Z-disk disorganisation, granulofilamentous material accumulation along with Hspb8, αB-crystallin (HSPB5/CRYAB), and desmin aggregates. The presence of the aggregates correlated with reduced markers of effective autophagy. The sciatic nerve of the homozygous knock-in mice was characterized by low autophagy potential in pre-symptomatic and Hspb8 aggregates in post-symptomatic animals. On the other hand, the sciatic nerve of the homozygous knock-out mice presented a normal morphology and their distal muscle displayed accumulation of abnormal mitochondria but intact myofiber and Z-line organisation. Our data, therefore, suggest that toxic gain-of-function of mutant Hspb8 aggregates is a major contributor to the peripheral neuropathy and the myopathy. In addition, mutant Hspb8 induces

  7. A buoyancy-based screen of Drosophila larvae for fat-storage mutants reveals a role for Sir2 in coupling fat storage to nutrient availability.

    Directory of Open Access Journals (Sweden)

    Tânia Reis

    2010-11-01

    Full Text Available Obesity has a strong genetic component, but few of the genes that predispose to obesity are known. Genetic screens in invertebrates have the potential to identify genes and pathways that regulate the levels of stored fat, many of which are likely to be conserved in humans. To facilitate such screens, we have developed a simple buoyancy-based screening method for identifying mutant Drosophila larvae with increased levels of stored fat. Using this approach, we have identified 66 genes that when mutated increase organismal fat levels. Among these was a sirtuin family member, Sir2. Sirtuins regulate the storage and metabolism of carbohydrates and lipids by deacetylating key regulatory proteins. However, since mammalian sirtuins function in many tissues in different ways, it has been difficult to define their role in energy homeostasis accurately under normal feeding conditions. We show that knockdown of Sir2 in the larval fat body results in increased fat levels. Moreover, using genetic mosaics, we demonstrate that Sir2 restricts fat accumulation in individual cells of the fat body in a cell-autonomous manner. Consistent with this function, changes in the expression of metabolic enzymes in Sir2 mutants point to a shift away from catabolism. Surprisingly, although Sir2 is typically upregulated under conditions of starvation, Sir2 mutant larvae survive better than wild type under conditions of amino-acid starvation as long as sugars are provided. Our findings point to a Sir2-mediated pathway that activates a catabolic response to amino-acid starvation irrespective of the sugar content of the diet.

  8. Genetic and systems level analysis of Drosophila sticky/citron kinase and dFmr1 mutants reveals common regulation of genetic networks

    Directory of Open Access Journals (Sweden)

    Zarnescu Daniela C

    2008-11-01

    Full Text Available Abstract Background In Drosophila, the genes sticky and dFmr1 have both been shown to regulate cytoskeletal dynamics and chromatin structure. These genes also genetically interact with Argonaute family microRNA regulators. Furthermore, in mammalian systems, both genes have been implicated in neuronal development. Given these genetic and functional similarities, we tested Drosophila sticky and dFmr1 for a genetic interaction and measured whole genome expression in both mutants to assess similarities in gene regulation. Results We found that sticky mutations can dominantly suppress a dFmr1 gain-of-function phenotype in the developing eye, while phenotypes produced by RNAi knock-down of sticky were enhanced by dFmr1 RNAi and a dFmr1 loss-of-function mutation. We also identified a large number of transcripts that were misexpressed in both mutants suggesting that sticky and dFmr1 gene products similarly regulate gene expression. By integrating gene expression data with a protein-protein interaction network, we found that mutations in sticky and dFmr1 resulted in misexpression of common gene networks, and consequently predicted additional specific phenotypes previously not known to be associated with either gene. Further phenotypic analyses validated these predictions. Conclusion These findings establish a functional link between two previously unrelated genes. Microarray analysis indicates that sticky and dFmr1 are both required for regulation of many developmental genes in a variety of cell types. The diversity of transcripts regulated by these two genes suggests a clear cause of the pleiotropy that sticky and dFmr1 mutants display and provides many novel, testable hypotheses about the functions of these genes. As both of these genes are implicated in the development and function of the mammalian brain, these results have relevance to human health as well as to understanding more general biological processes.

  9. A combined physiological and proteomic approach to reveal lactic-acid-induced alterations in Lactobacillus casei Zhang and its mutant with enhanced lactic acid tolerance.

    Science.gov (United States)

    Wu, Chongde; Zhang, Juan; Chen, Wei; Wang, Miao; Du, Guocheng; Chen, Jian

    2012-01-01

    Lactobacillus casei has traditionally been recognized as a probiotic and frequently used as an adjunct culture in fermented dairy products, where acid stress is an environmental condition commonly encountered. In the present study, we carried out a comparative physiological and proteomic study to investigate lactic-acid-induced alterations in Lactobacillus casei Zhang (WT) and its acid-resistant mutant. Analysis of the physiological data showed that the mutant exhibited 33.8% higher glucose phosphoenolpyruvate:sugar phosphotransferase system activity and lower glycolytic pH compared with the WT under acidic conditions. In addition, significant differences were detected in both cells during acid stress between intracellular physiological state, including intracellular pH, H(+)-ATPase activity, and intracellular ATP pool. Comparison of the proteomic data based on 2D-DIGE and i-TRAQ indicated that acid stress invoked a global change in both strains. The mutant protected the cells against acid damage by regulating the expression of key proteins involved in cellular metabolism, DNA replication, RNA synthesis, translation, and some chaperones. Proteome results were validated by Lactobacillus casei displaying higher intracellular aspartate and arginine levels, and the survival at pH 3.3 was improved 1.36- and 2.10-fold by the addition of 50-mM aspartate and arginine, respectively. To our knowledge, this is the first demonstration that aspartate may be involved in acid tolerance in Lactobacillus casei. Results presented here may help us understand acid resistance mechanisms and help formulate new strategies to enhance the industrial applications of this species.

  10. Analysis of the presence of cell proliferation-related molecules in the Tgf-β3 null mutant mouse palate reveals misexpression of EGF and Msx-1.

    Science.gov (United States)

    del Río, A; Barrio, M C; Murillo, J; Maldonado, E; López-Gordillo, Y; Martínez-Sanz, E; Martínez, M L; Martínez-Álvarez, C

    2011-01-01

    The Tgf-β(3) null mutant mouse palate presents several cellular anomalies that lead to the appearance of cleft palate. One of them concerns the cell proliferation of both the palatal medial edge epithelium and mesenchyme. In this work, our aim was to determine whether there was any variation in the presence/distribution of several cell proliferation-related molecules that could be responsible for the cell proliferation defects observed in these palates. Our results showed no difference in the presence of EGF-R, PDGF-A, TGF-β(2), Bmp-2, and Bmp-4, and differences were minimal for FGF-10 and Shh. However, the expression of EGF and Msx-1 changed substantially. The shift of the EGF protein expression was the one that most correlated with that of cell proliferation. This molecule is regulated by TGF-β(3), and experiments blocking its activity in culture suggest that EGF misexpression in the Tgf-β(3) null mutant mouse palate plays a role in the cell proliferation defect observed. Copyright © 2010 S. Karger AG, Basel.

  11. Intrinsic MYH7 expression regulation contributes to tissue level allelic imbalance in hypertrophic cardiomyopathy.

    Science.gov (United States)

    Montag, Judith; Syring, Mandy; Rose, Julia; Weber, Anna-Lena; Ernstberger, Pia; Mayer, Anne-Kathrin; Becker, Edgar; Keyser, Britta; Dos Remedios, Cristobal; Perrot, Andreas; van der Velden, Jolanda; Francino, Antonio; Navarro-Lopez, Francesco; Ho, Carolyn Yung; Brenner, Bernhard; Kraft, Theresia

    2017-08-01

    HCM, the most common inherited cardiac disease, is mainly caused by mutations in sarcomeric genes. More than a third of the patients are heterozygous for mutations in the MYH7 gene encoding for the β-myosin heavy chain. In HCM-patients, expression of the mutant and the wildtype allele can be unequal, thus leading to fractions of mutant and wildtype mRNA and protein which deviate from 1:1. This so-called allelic imbalance was detected in whole tissue samples but also in individual cells. There is evidence that the severity of HCM not only depends on the functional effect of the mutation itself, but also on the fraction of mutant protein in the myocardial tissue. Allelic imbalance has been shown to occur in a broad range of genes. Therefore, we aimed to examine whether the MYH7-alleles are intrinsically expressed imbalanced or whether the allelic imbalance is solely associated with the disease. We compared the expression of MYH7-alleles in non-HCM donors and in HCM-patients with different MYH7-missense mutations. In the HCM-patients, we identified imbalanced as well as equal expression of both alleles. Also at the protein level, allelic imbalance was determined. Most interestingly, we also discovered allelic imbalance and balance in non-HCM donors. Our findings therefore strongly indicate that apart from mutation-specific mechanisms, also non-HCM associated allelic-mRNA expression regulation may account for the allelic imbalance of the MYH7 gene in HCM-patients. Since the relative amount of mutant mRNA and protein or the extent of allelic imbalance has been associated with the severity of HCM, individual analysis of the MYH7-allelic expression may provide valuable information for the prognosis of each patient.

  12. Analysis of the CCR5 gene coding region diversity in five South American populations reveals two new non-synonymous alleles in Amerindians and high CCR5*D32 frequency in Euro-Brazilians

    Directory of Open Access Journals (Sweden)

    Angelica B.W. Boldt

    2009-01-01

    Full Text Available The CC chemokine receptor 5 (CCR5 molecule is an important co-receptor for HIV. The effect of the CCR5*D32 allele in susceptibility to HIV infection and AIDS disease is well known. Other alleles than CCR5*D32 have not been analysed before, neither in Amerindians nor in the majority of the populations all over the world. We investigated the distribution of the CCR5 coding region alleles in South Brazil and noticed a high CCR5*D32 frequency in the Euro-Brazilian population of the Paraná State (9.3%, which is the highest thus far reported for Latin America. The D32 frequency is even higher among the Euro-Brazilian Mennonites (14.2%. This allele is uncommon in Afro-Brazilians (2.0%, rare in the Guarani Amerindians (0.4% and absent in the Kaingang Amerindians and the Oriental-Brazilians. R223Q is common in the Oriental-Brazilians (7.7% and R60S in the Afro-Brazilians (5.0%. A29S and L55Q present an impaired response to b-chemokines and occurred in Afro- and Euro-Brazilians with cumulative frequencies of 4.4% and 2.7%, respectively. Two new non-synonymous alleles were found in Amerindians: C323F (g.3729G > T in Guarani (1.4% and Y68C (g.2964A > G in Kaingang (10.3%. The functional characteristics of these alleles should be defined and considered in epidemiological investigations about HIV-1 infection and AIDS incidence in Amerindian populations.

  13. Near infrared spectra indicate specific mutant endosperm genes and reveal a new mechanism for substituting starch with (1-->3,1-->4)-[beta]-glucan in barley

    DEFF Research Database (Denmark)

    Munck, L.; Møller, B.; Jacobsen, Susanne

    2004-01-01

    -->3,1-->4)-[beta]-glucan (up to 15-20%), thus, maintaining a constant production of polysaccharides at 50-55%, within the range of normal barley.The spectral tool was tested by an independent data set with six mutants with unknown polysaccharide composition. Spectral data from four of these were classified within...... the high (1-->3,1-->4)-[beta]-glucan BG lys5 cluster in a PCA. Their high (1-->3,1-->4)-[beta]-glucan and low starch content was verified. It is concluded that genetic diversity such as from gene regulated polysaccharide and storage protein pathways in the endosperm tissue can be discovered directly from...... the phenotype by chemometric classification of a spectral library, representing the digitised phenome from a barley gene bank....

  14. Distinct roles of autophagy-dependent and -independent functions of FIP200 revealed by generation and analysis of a mutant knock-in mouse model

    Science.gov (United States)

    Chen, Song; Wang, Chenran; Yeo, Syn; Liang, Chun-Chi; Okamoto, Takako; Sun, Shaogang; Wen, Jian; Guan, Jun-Lin

    2016-01-01

    Autophagy is an evolutionarily conserved cellular process controlled through a set of essential autophagy genes (Atgs). However, there is increasing evidence that most, if not all, Atgs also possess functions independent of their requirement in canonical autophagy, making it difficult to distinguish the contributions of autophagy-dependent or -independent functions of a particular Atg to various biological processes. To distinguish these functions for FIP200 (FAK family-interacting protein of 200 kDa), an Atg in autophagy induction, we examined FIP200 interaction with its autophagy partner, Atg13. We found that residues 582–585 (LQFL) in FIP200 are required for interaction with Atg13, and mutation of these residues to AAAA (designated the FIP200-4A mutant) abolished its canonical autophagy function in vitro. Furthermore, we created a FIP200-4A mutant knock-in mouse model and found that specifically blocking FIP200 interaction with Atg13 abolishes autophagy in vivo, providing direct support for the essential role of the ULK1/Atg13/FIP200/Atg101 complex in the process beyond previous studies relying on the complete knockout of individual components. Analysis of the new mouse model showed that nonautophagic functions of FIP200 are sufficient to fully support embryogenesis by maintaining a protective role in TNFα-induced apoptosis. However, FIP200-mediated canonical autophagy is required to support neonatal survival and tumor cell growth. These studies provide the first genetic evidence linking an Atg's autophagy and nonautophagic functions to different biological processes in vivo. PMID:27013233

  15. The Arabidopsis szl1 Mutant Reveals a Critical Role of β-Carotene in Photosystem I Photoprotection1[C][W

    Science.gov (United States)

    Cazzaniga, Stefano; Li, Zhirong; Niyogi, Krishna K.; Bassi, Roberto; Dall’Osto, Luca

    2012-01-01

    Carotenes and their oxygenated derivatives, the xanthophylls, are structural determinants in both photosystems (PS) I and II. They bind and stabilize photosynthetic complexes, increase the light-harvesting capacity of chlorophyll-binding proteins, and have a major role in chloroplast photoprotection. Localization of carotenoid species within each PS is highly conserved: Core complexes bind carotenes, whereas peripheral light-harvesting systems bind xanthophylls. The specific functional role of each xanthophyll species has been recently described by genetic dissection, however the in vivo role of carotenes has not been similarly defined. Here, we have analyzed the function of carotenes in photosynthesis and photoprotection, distinct from that of xanthophylls, by characterizing the suppressor of zeaxanthin-less (szl) mutant of Arabidopsis (Arabidopsis thaliana) which, due to the decreased activity of the lycopene-β-cyclase, shows a lower carotene content than wild-type plants. When grown at room temperature, mutant plants showed a lower content in PSI light-harvesting complex I complex than the wild type, and a reduced capacity for chlorophyll fluorescence quenching, the rapidly reversible component of nonphotochemical quenching. When exposed to high light at chilling temperature, szl1 plants showed stronger photoxidation than wild-type plants. Both PSI and PSII from szl1 were similarly depleted in carotenes and yet PSI activity was more sensitive to light stress than PSII as shown by the stronger photoinhibition of PSI and increased rate of singlet oxygen release from isolated PSI light-harvesting complex I complexes of szl1 compared with the wild type. We conclude that carotene depletion in the core complexes impairs photoprotection of both PS under high light at chilling temperature, with PSI being far more affected than PSII. PMID:23029671

  16. Mutants of GABA transaminase (POP2 suppress the severe phenotype of succinic semialdehyde dehydrogenase (ssadh mutants in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Frank Ludewig

    Full Text Available BACKGROUND: The gamma-aminubutyrate (GABA shunt bypasses two steps of the tricarboxylic acid cycle, and is present in both prokaryotes and eukaryotes. In plants, the pathway is composed of the calcium/calmodulin-regulated cytosolic enzyme glutamate decarboxylase (GAD, the mitochondrial enzymes GABA transaminase (GABA-T; POP2 and succinic semialdehyde dehydrogenase (SSADH. We have previously shown that compromising the function of the GABA-shunt, by disrupting the SSADH gene of Arabidopsis, causes enhanced accumulation of reactive oxygen intermediates (ROIs and cell death in response to light and heat stress. However, to date, genetic investigations of the relationships between enzymes of the GABA shunt have not been reported. PRINCIPAL FINDINGS: To elucidate the role of succinic semialdehyde (SSA, gamma-hydroxybutyrate (GHB and GABA in the accumulation of ROIs, we combined two genetic approaches to suppress the severe phenotype of ssadh mutants. Analysis of double pop2 ssadh mutants revealed that pop2 is epistatic to ssadh. Moreover, we isolated EMS-generated mutants suppressing the phenotype of ssadh revealing two new pop2 alleles. By measuring thermoluminescence at high temperature, the peroxide contents of ssadh and pop2 mutants were evaluated, showing that only ssadh plants accumulate peroxides. In addition, pop2 ssadh seedlings are more sensitive to exogenous SSA or GHB relative to wild type, because GHB and/or SSA accumulate in these plants. SIGNIFICANCE: We conclude that the lack of supply of succinate and NADH to the TCA cycle is not responsible for the oxidative stress and growth retardations of ssadh mutants. Rather, we suggest that the accumulation of SSA, GHB, or both, produced downstream of the GABA-T transamination step, is toxic to the plants, resulting in high ROI levels and impaired development.

  17. Family-based transmission disequilibrium test (TDT) and case-control association studies reveal surfactant protein A (SP-A) susceptibility alleles for respiratory distress syndrome (RDS) and possible race differences

    NARCIS (Netherlands)

    Floros, J.; Fan, R.; Matthews, A.; DiAngelo, S.; Luo, J.; Nielsen, H.; Dunn, M.; Gewolb, I. H.; Koppe, J.; Van Sonderen, L.; Farri-Kostopoulos, L.; Tzaki, M.; Rämet, M.; Merrill, J.

    2001-01-01

    A key cause of respiratory distress syndrome (RDS) in the prematurely born infant is deficiency of pulmonary surfactant, a lipoprotein complex. Both low levels of surfactant protein A (SP-A) and SP-A alleles have been associated with RDS. Using the candidate gene approach, we performed family-based

  18. The circling mutant Pcdh15roda is a new mouse model for hearing loss.

    Science.gov (United States)

    Torres, Adriana Amorim; Rzadzinska, Agnieszka K; Ribeiro, Andrea Frozino; Silva, Daniel Almeida da Silva E; Guénet, Jean-Louis; Massironi, Sílvia Maria Gomes; Godard, Ana Lúcia Brunialti

    2013-01-01

    Mouse mutagenesis is a key tool for studying gene function and several mutant alleles have been described and constitute mouse models for human hereditary diseases. Genetic hearing loss represents over 50% of all hearing loss cases in children and, due to the heterogeneity of the disorder, there is still a demand for the isolation and characterization of new genes and alleles. Here we report phenotypic and molecular characterization of a new mouse model for hereditary hearing loss. The mutant rodador, isolated by Massironi and colleagues in 2006, presents an autosomal recessive disorder characterized by deafness and balance dysfunction associated with abnormal stereocilia in the inner ear. The mutation was mapped to mouse chromosome 10, and characterization of the gene Pcdh15 revealed an AT-to-GC transition in intron 23 of mutant animals. The alteration led to the switch of a dinucleotide ApA for ApG, creating a novel intronic acceptor splice site, which leads to incorporation of eight intronic bases into the processed mRNA and alteration of the downstream reading frame. In silico analysis indicated that the mutated protein is truncated and lacks two cadherin domains, and the transmembrane and cytoplasmic domains. Real Time PCR analyses revealed a significantly reduced Pcdh15 mRNA level in the brain of mutant mice, which might be due to the mechanism of non-sense mediated decay. In man, mutations in the orthologue PCDH15 cause non-syndromic deafness and Usher Syndrome Type 1F, a genetic disorder characterized by hearing loss and retinitis pigmentosa. Rodador mouse constitutes a new model for studying deafness in these conditions and may help in the comprehension of the pathogeneses of the disease, as well as of the mechanisms involved in the morphogenesis and function of inner ear stereocilia. This is a new ENU-induced allele and the first isolated in a BALB/c background. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Radiation studies in Cajanus cajan: meiotic behaviour in some M/sub 2/ mutants

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, S.S.N.; Akhaury, S.B. (Ranchi Univ. (India). Dept. of Botany)

    1982-01-01

    A qualitative study of the mutants produced in M/sub 2/ generation has been made. The mutants were classified as: (1) chlorophyll mutant, (2) morphological mutant, (3) pollen mutant, (4) semi-sterile and (5) sterile mutant. Cytological investigations of pollen mutants, sterile and semi-sterile mutants have revealed that these mutants generally arise at higher dose levels (20 Kr and 25 Kr).

  20. Quantum mechanical/molecular mechanical calculated reactivity networks reveal how cytochrome P450cam and Its T252A mutant select their oxidation pathways.

    Science.gov (United States)

    Wang, Binju; Li, Chunsen; Dubey, Kshatresh Dutta; Shaik, Sason

    2015-06-17

    Quantum mechanical/molecular mechanical calculations address the longstanding-question of a "second oxidant" in P450 enzymes wherein the proton-shuttle, which leads to formation of the "primary-oxidant" Compound I (Cpd I), was severed by mutating the crucial residue (in P450cam: Threonine-252-to-Alanine, hence T252A). Investigating the oxidant candidates Cpd I, ferric hydroperoxide, and ferric hydrogen peroxide (Fe(III)(O2H2)), and their reactions, generates reactivity networks which enable us to rule out a "second oxidant" and at the same time identify an additional coupling pathway that is responsible for the epoxidation of 5-methylenylcamphor by the T252A mutant. In this "second-coupling pathway", the reaction starts with the Fe(III)(O2H2) intermediate, which transforms to Cpd I via a O-O homolysis/H-abstraction mechanism. The persistence of Fe(III)(O2H2) and its oxidative reactivity are shown to be determined by interplay of substrate and protein. The substrate 5-methylenylcamphor prevents H2O2 release, while the protein controls the Fe(III)(O2H2) conversion to Cpd I by nailing-through hydrogen-bonding interactions-the conformation of the HO(•) radical produced during O-O homolysis. This conformation prevents HO(•) attack on the porphyrin's meso position, as in heme oxygenase, and prefers H-abstraction from Fe(IV)OH thereby generating H2O + Cpd I. Cpd I then performs substrate oxidations. Camphor cannot prevent H2O2 release and hence the T252A mutant does not oxidize camphor. This "second pathway" transpires also during H2O2 shunting of the cycle of wild-type P450cam, where the additional hydrogen-bonding with Thr252 prevents H2O2 release, and contributes to a successful Cpd I formation. The present results lead to a revised catalytic cycle of Cytochrome P450cam.

  1. Transcriptome analysis of an mvp mutant reveals important changes in global gene expression and a role for methyl jasmonate in vernalization and flowering in wheat.

    Science.gov (United States)

    Diallo, Amadou Oury; Agharbaoui, Zahra; Badawi, Mohamed A; Ali-Benali, Mohamed Ali; Moheb, Amira; Houde, Mario; Sarhan, Fathey

    2014-06-01

    The einkorn wheat mutant mvp-1 (maintained vegetative phase 1) has a non-flowering phenotype caused by deletions including, but not limited to, the genes CYS, PHYC, and VRN1. However, the impact of these deletions on global gene expression is still unknown. Transcriptome analysis showed that these deletions caused the upregulation of several pathogenesis-related (PR) and jasmonate-responsive genes. These results suggest that jasmonates may be involved in flowering and vernalization in wheat. To test this hypothesis, jasmonic acid (JA) and methyl jasmonate (MeJA) content in mvp and wild-type plants was measured. The content of JA was comparable in all plants, whereas the content of MeJA was higher by more than 6-fold in mvp plants. The accumulation of MeJA was also observed in vernalization-sensitive hexaploid winter wheat during cold exposure. This accumulation declined rapidly once plants were deacclimated under floral-inductive growth conditions. This suggests that MeJA may have a role in floral transition. To confirm this result, we treated vernalization-insensitive spring wheat with MeJA. The treatment delayed flowering with significant downregulation of both TaVRN1 and TaFT1 genes. These data suggest a role for MeJA in modulating vernalization and flowering time in wheat. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Properties of a mutant recA-encoded protein reveal a possible role for Escherichia coli recF-encoded protein in genetic recombination

    International Nuclear Information System (INIS)

    Madiraju, M.V.; Templin, A.; Clark, A.J.

    1988-01-01

    A mutation partially suppressing the UV sensitivity caused by recF143 in a uvrA6 background was located at codon 37 of recA where GTG (valine) became ATG (methionine). This mutation, originally named srf-803, was renamed recA803. Little if any suppression of the recF143 defect in UV induction of a lexA regulon promoter was detected. This led to the hypothesis that a defect in recombination repair of UV damage was suppressed by recA803. The mutant RecA protein (RecA803) was purified and compared with wild-type protein (RecA+) as a catalyst of formation of joint molecules. Under suboptimal conditions, RecA803 produces both a higher rate of formation and a higher yield of joint molecules. The suboptimal conditions tested included addition of single-stranded DNA binding protein to single-stranded DNA prior to addition of RecA. We hypothesize that the ability of RecA803 to overcome interference by single-stranded DNA binding protein is the property that allows recA803 to suppress partially the deficiency in repair caused by recF mutations in the uvrA6 background. Implications of this hypothesis for the function of RecF protein in recombination are discussed

  3. LC–MS Proteomics Analysis of the Insulin/IGF-1-Deficient Caenorhabditis elegans daf-2(e1370) Mutant Reveals Extensive Restructuring of Intermediary Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Depuydt, Geert; Xie, Fang; Petyuk, Vladislav A.; Smolders, Arne; Brewer, Heather M.; Camp, David G.; Smith, Richard D.; Braeckman, Bart P.

    2014-04-04

    The insulin/IGF-1 receptor is a major known determinant of dauer formation, stress resistance, longevity, and metabolism in Caenorhabditis elegans. In the past, whole-genome transcript profiling was used extensively to study differential gene expression in response to reduced insulin/IGF-1 signaling, including the expression levels of metabolism-associated genes. Taking advantage of the recent developments in quantitative liquid chromatography mass spectrometry (LC–MS)-based proteomics, we profiled the proteomic changes that occur in response to activation of the DAF-16 transcription factor in the germline-less glp-4(bn2);daf-2(e1370) receptor mutant. Strikingly, the daf-2 profile suggests extensive reorganization of intermediary metabolism, characterized by the upregulation of many core intermediary metabolic pathways. These include glycolysis/gluconeogenesis, glycogenesis, pentose phosphate cycle, citric acid cycle, glyoxylate shunt, fatty acid β-oxidation, one-carbon metabolism, propionate and tyrosine catabolism, and complexes I, II, III, and V of the electron transport chain. Interestingly, we found simultaneous activation of reciprocally regulated metabolic pathways, which is indicative of spatiotemporal coordination of energy metabolism and/or extensive post-translational regulation of these enzymes. Finally, this restructuring of daf-2 metabolism is reminiscent to that of hypometabolic dauers, allowing the efficient and economical utilization of internal nutrient reserves and possibly also shunting metabolites through alternative energy-generating pathways to sustain longevity.

  4. LC-MS Proteomics Analysis of the Insulin/IGF-1 Deficient Caenorhabditis elegans daf-2(e1370) Mutant Reveals Extensive Restructuring of Intermediary Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Depuydt, Geert G.; Xie, Fang; Petyuk, Vladislav A.; Smolders, Arne; Brewer, Heather M.; Camp, David G.; Smith, Richard D.; Braeckman, Bart P.

    2014-02-20

    The insulin/IGF-1 receptor is a major known determinant of dauer formation, stress resistance, longevity and metabolism in C. elegans. In the past, whole-genome transcript profiling was used extensively to study differential gene expression in response to reduced insulin/IGF-1 signaling, including expression levels of metabolism-associated genes. Taking advantage of the recent developments in quantitative liquid chromatography mass-spectrometry (LC-MS) based proteomics, we profiled the proteomic changes that occur in response to activation of the DAF-16 transcription factor in the germline-less glp-4(bn2); daf-2(e1370) receptor mutant. Strikingly, the daf-2 profile suggests extensive reorganization of intermediary metabolism, characterized by the up-regulation of many core intermediary metabolic pathways. These include, glycolysis/gluconeogenesis, glycogenesis, pentose phosphate cycle, citric acid cycle, glyoxylate shunt, fatty acid β-oxidation, one-carbon metabolism, propionate and tyrosine catabolism, and complex I, II, III and V of the electron transport chain. Interestingly, we found simultaneous activation of reciprocally regulated metabolic pathways, which is indicative for spatio-temporal coordination of energy metabolism and/or extensive post-translational regulation of these enzymes. This restructuring of daf-2 metabolism is reminiscent to that of hypometabolic dauers, allowing the efficient and economical utilization of internal nutrient reserves, possibly also shunting metabolites through alternative energy-generating pathways, in order to sustain longevity.

  5. Comparison Between Several Integrase-defective Lentiviral Vectors Reveals Increased Integration of an HIV Vector Bearing a D167H Mutant

    Directory of Open Access Journals (Sweden)

    Muhammad Qamar Saeed

    2014-01-01

    Full Text Available HIV-1 derived vectors are among the most efficient for gene transduction in mammalian tissues. As the parent virus, they carry out vector genome insertion into the host cell chromatin. Consequently, their preferential integration in transcribed genes raises several conceptual and safety issues. To address part of these questions, HIV-derived vectors have been engineered to be nonintegrating. This was mainly achieved by mutating HIV-1 integrase at functional hotspots of the enzyme enabling the development of streamlined nuclear DNA circles functional for transgene expression. Few integrase mutant vectors have been successfully tested so far for gene transfer. They are cleared with time in mitotic cells, but stable within nondividing retina cells or neurons. Here, we compared six HIV vectors carrying different integrases, either wild type or with different mutations (D64V, D167H, Q168A, K186Q+Q214L+Q216L, and RRK262-264AAH shown to modify integrase enzymatic activity, oligomerization, or interaction with key cellular cofactor of HIV DNA integration as LEDGF/p75 or TNPO3. We show that these mutations differently affect the transduction efficiency as well as rates and patterns of integration of HIV-derived vectors suggesting their different processing in the nucleus. Surprisingly and most interestingly, we report that an integrase carrying the D167H substitution improves vector transduction efficiency and integration in both HEK-293T and primary CD34+ cells.

  6. LC–MS Proteomics Analysis of the Insulin/IGF-1-Deficient Caenorhabditis elegans daf-2(e1370) Mutant Reveals Extensive Restructuring of Intermediary Metabolism

    Science.gov (United States)

    2015-01-01

    The insulin/IGF-1 receptor is a major known determinant of dauer formation, stress resistance, longevity, and metabolism in Caenorhabditis elegans. In the past, whole-genome transcript profiling was used extensively to study differential gene expression in response to reduced insulin/IGF-1 signaling, including the expression levels of metabolism-associated genes. Taking advantage of the recent developments in quantitative liquid chromatography mass spectrometry (LC–MS)-based proteomics, we profiled the proteomic changes that occur in response to activation of the DAF-16 transcription factor in the germline-less glp-4(bn2);daf-2(e1370) receptor mutant. Strikingly, the daf-2 profile suggests extensive reorganization of intermediary metabolism, characterized by the upregulation of many core intermediary metabolic pathways. These include glycolysis/gluconeogenesis, glycogenesis, pentose phosphate cycle, citric acid cycle, glyoxylate shunt, fatty acid β-oxidation, one-carbon metabolism, propionate and tyrosine catabolism, and complexes I, II, III, and V of the electron transport chain. Interestingly, we found simultaneous activation of reciprocally regulated metabolic pathways, which is indicative of spatiotemporal coordination of energy metabolism and/or extensive post-translational regulation of these enzymes. This restructuring of daf-2 metabolism is reminiscent to that of hypometabolic dauers, allowing the efficient and economical utilization of internal nutrient reserves and possibly also shunting metabolites through alternative energy-generating pathways to sustain longevity. PMID:24555535

  7. Characterization of five new mutants in the carboxyl-terminal domain of human apolipoprotein E: No cosegregation with severe hyperlipidemia

    Energy Technology Data Exchange (ETDEWEB)

    Maagdenberg, A.M.J.M. van den; Bruijn, I.H. de; Hofker, M.H.; Frants, R.R. (Leiden Univ. (Netherlands)); Knijff, P. de; Smelt, A.H.M.; Leuven, J.A.G.; van' t Hooft, F.; Assmann, G.; Havekes, L.M. (Univ. Hospital, Leiden (Netherlands)); Weng, Wei; Funke, H. (Westfalische Wilhelms-Universitaet, Muester (Germany))

    1993-05-01

    Assessment of the apolipoprotein E (apoE) phenotype by isoelectric focusing of both hyperlipidemic and normolipidemic individuals identified five new variants. All mutations were confined to the downstream part of the APOE gene by using denaturing gradient gel electrophoresis (DGGE). Sequence analysis revealed five new mutations causing unique amino acid substitutions in the carboxyl-terminal part of the protein containing the putative lipid-binding domain. Three hyperlipoproteinemic probands were carriers of the APOE*2(Va1236[r arrow]Glu) allele, the APOE*3(Cys112-Arg; Arg251[r arrow]Gly) allele, or the APOE*1(Arg158[r arrow]Cys; Leu252[r arrow]Glu) allele. DGGE of the region encoding the receptor-binding domain was useful for haplotyping the mutations at codons 112 and 158. Family studies failed to demonstrate cosegregation between the new mutations and severe hyperlipoproteinemia, although a number of carriers for the APOE*3(Cys112[r arrow]Arg; Arg251[r arrow]Gly) allele and the APOE*1(Arg158-Cys; Leu252[r arrow]Glu) allele expressed hypertriglyceridemia and/ or hypercholesterolemia. Two other mutant alleles, APOE*4[sup [minus

  8. Comparative transcriptome analyses of a late-maturing mandarin mutant and its original cultivar reveals gene expression profiling associated with citrus fruit maturation

    Directory of Open Access Journals (Sweden)

    Lu Wang

    2017-05-01

    Full Text Available Characteristics of late maturity in fruit are good agronomic traits for extending the harvest period and marketing time. However, underlying molecular basis of the late-maturing mechanism in fruit is largely unknown. In this study, RNA sequencing (RNA-Seq technology was used to identify differentially expressed genes (DEGs related to late-maturing characteristics from a late-maturing mutant ‘Huawan Wuzishatangju’ (HWWZSTJ (Citrus reticulata Blanco and its original line ‘Wuzishatangju’ (WZSTJ. A total of approximately 17.0 Gb and 84.2 M paried-end reads were obtained. DEGs were significantly enriched in the pathway of photosynthesis, phenylpropanoid biosynthesis, carotenoid biosynthesis, chlorophyll and abscisic acid (ABA metabolism. Thirteen candidate transcripts related to chlorophyll metabolism, carotenoid biosynthesis and ABA metabolism were analyzed using real-time quantitative PCR (qPCR at all fruit maturing stages of HWWZSTJ and WZSTJ. Chlorophyllase (CLH and divinyl reductase (DVR from chlorophyll metabolism, phytoene synthase (PSY and capsanthin/capsorubin synthase (CCS from carotenoid biosynthesis, and abscisic acid 8′-hydroxylase (AB1 and 9-cis-epoxycarotenoid dioxygenase (NCED1 from ABA metabolism were cloned and analyzed. The expression pattern of NCED1 indicated its role in the late-maturing characteristics of HWWZSTJ. There were 270 consecutive bases missing in HWWZSTJ in comparison with full-length sequences of NCED1 cDNA from WZSTJ. Those results suggested that NCED1 might play an important role in the late maturity of HWWZSTJ. This study provides new information on complex process that results in the late maturity of Citrus fruit at the transcriptional level.

  9. High-throughput sequencing reveals key genes and immune homeostatic pathways activated in myeloid dendritic cells by Porphyromonas gingivalis 381 and its fimbrial mutants.

    Science.gov (United States)

    Arjunan, P; El-Awady, A; Dannebaum, R O; Kunde-Ramamoorthy, G; Cutler, C W

    2016-02-01

    The human microbiome consists of highly diverse microbial communities that colonize our skin and mucosal surfaces, aiding in maintenance of immune homeostasis. The keystone pathogen Porphyromonas gingivalis induces a dysbiosis and disrupts immune homeostasis through as yet unclear mechanisms. The fimbrial adhesins of P. gingivalis facilitate biofilm formation, invasion of and dissemination by blood dendritic cells; hence, fimbriae may be key factors in disruption of immune homeostasis. In this study we employed RNA-sequencing transcriptome profiling to identify differentially expressed genes (DEGs) in human monocyte-derived dendritic cells (MoDCs) in response to in vitro infection/exposure by Pg381 or its isogenic mutant strains that solely express minor-Mfa1 fimbriae (DPG3), major-FimA fimbriae (MFI) or are deficient in both fimbriae (MFB) relative to uninfected control. Our results yielded a total of 479 DEGs that were at least two-fold upregulated and downregulated in MoDCs significantly (P ≤ 0.05) by all four strains and certain DEGs that were strain-specific. Interestingly, the gene ontology biological and functional analysis shows that the upregulated genes in DPG3-induced MoDCs were more significant than other strains and associated with inflammation, immune response, anti-apoptosis, cell proliferation, and other homeostatic functions. Both transcriptome and quantitative polymerase chain reaction results show that DPG3, which solely expresses Mfa1, increased ZNF366, CD209, LOX1, IDO1, IL-10, CCL2, SOCS3, STAT3 and FOXO1 gene expression. In conclusion, we have identified key DC-mediated immune homeostatic pathways that could contribute to dysbiosis in periodontal infection with P. gingivalis. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. AllelicImbalance: An R/ bioconductor package for detecting, managing, and visualizing allele expression imbalance data from RNA sequencing

    DEFF Research Database (Denmark)

    Gådin, Jesper R.; van't Hooft, Ferdinand M.; Eriksson, Per

    2015-01-01

    the possible biases. Results: We present AllelicImblance, a software program that is designed to detect, manage, and visualize allelic imbalances comprehensively. The purpose of this software is to allow users to pose genetic questions in any RNA sequencing experiment quickly, enhancing the general utility...... of RNA sequencing. The visualization features can reveal notable, non-trivial allelic imbalance behavior over specific regions, such as exons. Conclusions: The software provides a complete framework to perform allelic imbalance analyses of aligned RNA sequencing data, from detection to visualization...

  11. Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes.

    Science.gov (United States)

    Mehterov, Nikolay; Balazadeh, Salma; Hille, Jacques; Toneva, Valentina; Mueller-Roeber, Bernd; Gechev, Tsanko

    2012-10-01

    The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ, which stimulate the intracellular formation of H₂O₂ or superoxide anions, respectively, trigger cell death in loh2 but do not lead to visible damage in atr7. To study gene expression during oxidative stress and ROS-induced programmed cell death, two platforms for multi-parallel quantitative real-time PCR (qRT-PCR) analysis of 217 antioxidant and 180 ROS marker genes were employed. The qRT-PCR analyses revealed AT- and PQ-induced expression of many ROS-responsive genes mainly in loh2, confirming that an oxidative burst plays a role in the activation of the cell death in this mutant. Some of the genes were specifically regulated by either AT or PQ, serving as markers for particular types of ROS. Genes significantly induced by both AT and PQ in loh2 included transcription factors (ANAC042/JUB1, ANAC102, DREB19, HSFA2, RRTF1, ZAT10, ZAT12, ethylene-responsive factors), signaling compounds, ferritins, alternative oxidases, and antioxidant enzymes. Many of these genes were upregulated in atr7 compared to loh2 under non-stress conditions at the first time point, indicating that higher basal levels of ROS and higher antioxidant capacity in atr7 are responsible for the enhanced tolerance to oxidative stress and suggesting a possible tolerance against multiple stresses of this mutant. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  12. Mutation rate heterogeneity and the generation of allele diversity at the human minisatellite MS205 (D16S309).

    Science.gov (United States)

    May, C A; Jeffreys, A J; Armour, J A

    1996-11-01

    Many tandemly repeated minisatellite loci display extreme levels of length variation as a consequence of high rates of spontaneous germline mutation altering repeat copy number. Direct screening for new allele lengths by small-pool PCR has shown that instability at the human minisatellite locus MS205 (D16S309) is largely germline specific and usually results in the gain or loss of just a few repeat units. Structural analysis of the order of variant repeats has shown that these events occur preferentially at one end of the tandem array and can result in complex rearrangements including the inter-allelic transfer of repeat units. In contrast, putative mutants recovered from somatic DNA occur at a substantially lower rate and are simple and non-polar in nature. Germline mutation rates vary considerably between alleles, consistent with regulation occurring in cis. Although examination of DNA sequence polymorphisms immediately flanking the minisatellite reveals no definitive associations with germline mutation rate variation, differences in rate may be paralleled by changes in mutation spectrum. These findings help to explain the diversity of MS205 allele structures in modern humans and suggest a common mutation pathway with some other minisatellites.

  13. SEQUENCE OF THE STRUCTURAL GENE FOR GRANULE-BOUND STARCH SYNTHASE OF POTATO (SOLANUM-TUBEROSUM L) AND EVIDENCE FOR A SINGLE POINT DELETION IN THE AMF ALLELE

    NARCIS (Netherlands)

    van der Leij, Feike R.; VISSER, RGF; Ponstein, Anne S.; Jacobsen, Evert; Feenstra, Willem

    The genomic sequence of the potato gene for starch granule-bound starch synthase (GBSS; "waxy protein") has been determined for the wild-type allele of a monoploid genotype from which an amylose-free (amf) mutant was derived, and for the mutant part of the amf allele. Comparison of the wild-type

  14. Evaluation and genetic analysis of semi-dwarf mutants in rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Awan, M.A.; Cheema, A.A.; Tahir, G.R.

    1984-01-01

    Four semi-dwarf mutants namely DM16-5-1, DM16-5-2, DM-2 and DM107-4 were derived from the local tall basmati cultivar. The mode of reduction of internode length was studied in DM107-4. The reduction in culm length was due to a corresponding but disproportionate reduction in all the internodes. It was inferred that reduction in internode length contributes more towards reduction in height as compared to the reduction in the total number of internodes. The effect of semi-dwarfism on some yield components (panicle characters) was studied in two semi-dwarf mutants viz. DM16-5-1 and DM107-4 compared to Basmati 370. A marginal reduction in the panicle axis, primary branches per panicle, secondary branches per primary branch per panicle, spikelets borne on secondary branches and total number of spikelets per panicle was observed in DM16-5-1, whereas, a significant reduction of these characters was observed in DM107-4. Evaluation of the semi-dwarf mutants with respect to grain yield and harvest index showed that all the mutants possess high yield potential with higher harvest index values compared to the parent cultivar. Genetic analysis for plant height in 4x4 diallel involving semi-dwarf mutants revealed that mutant DM107-4 carries mainly recessive alleles while mutant DM16-5-1 showed some dominance effects as assessed through the estimates of genetic components of variation and Vr,Wr graph analysis. The semi-dwarf mutants have good potential for use as parents in cross-breeding programmes. (author)

  15. Isolation of a novel mutant gene for soil-surface rooting in rice (Oryza sativa L.).

    Science.gov (United States)

    Hanzawa, Eiko; Sasaki, Kazuhiro; Nagai, Shinsei; Obara, Mitsuhiro; Fukuta, Yoshimichi; Uga, Yusaku; Miyao, Akio; Hirochika, Hirohiko; Higashitani, Atsushi; Maekawa, Masahiko; Sato, Tadashi

    2013-11-20

    Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this study, we examined the genetic and physiological characteristics of this mutant. The primary roots of the mutant showed no gravitropic response from the seedling stage on, whereas the gravitropic response of the shoots was normal. Segregation analyses by using an F2 population derived from a cross between the soil-surface rooting mutant and wild-type Nipponbare indicated that the trait was controlled by a single recessive gene, designated as sor1. Fine mapping by using an F2 population derived from a cross between the mutant and an indica rice cultivar, Kasalath, revealed that sor1 was located within a 136-kb region between the simple sequence repeat markers RM16254 and 2935-6 on the terminal region of the short arm of chromosome 4, where 13 putative open reading frames (ORFs) were found. We sequenced these ORFs and detected a 33-bp deletion in one of them, Os04g0101800. Transgenic plants of the mutant transformed with the genomic fragment carrying the Os04g0101800 sequence from Nipponbare showed normal gravitropic responses and no soil-surface rooting. These results suggest that sor1, a rice mutant causing soil-surface rooting and altered root gravitropic response, is allelic to Os04g0101800, and that a 33-bp deletion in the coding region of this gene causes the mutant phenotypes.

  16. Characterization of Lactococcus lactis mutants with improved performance at high temperatures and potential dairy applications

    DEFF Research Database (Denmark)

    Chen, Jun

    microarray analysis revealed apparent differences in the transcriptional response to heat between the mutant and parent. It was found that SNPs preceding gene groESL and ribU resulted in over-expression of chaperone proteins GroES-GroEL, and membrane associated riboflavin transporter protein RibU in TM29......, respectively. Moreover, a large deletion in TM29 caused the inactivation of 10 genes (llmg_1349-llmg_1358). Through allelic replacement and gene knockout followed by fitness assessment, four main positive mutations were eventually discovered. The SNP preceding groESL and deletion of llmg_1349-llmg_1358...

  17. Novel Escherichia coli umuD′ Mutants: Structure-Function Insights into SOS Mutagenesis

    Science.gov (United States)

    McLenigan, Mary; Peat, Thomas S.; Frank, Ekaterina G.; McDonald, John P.; Gonzalez, Martín; Levine, Arthur S.; Hendrickson, Wayne A.; Woodgate, Roger

    1998-01-01

    Although it has been 10 years since the discovery that the Escherichia coli UmuD protein undergoes a RecA-mediated cleavage reaction to generate mutagenically active UmuD′, the function of UmuD′ has yet to be determined. In an attempt to elucidate the role of UmuD′ in SOS mutagenesis, we have utilized a colorimetric papillation assay to screen for mutants of a hydroxylamine-treated, low-copy-number umuD′ plasmid that are unable to promote SOS-dependent spontaneous mutagenesis. Using such an approach, we have identified 14 independent umuD′ mutants. Analysis of these mutants revealed that two resulted from promoter changes which reduced the expression of wild-type UmuD′, three were nonsense mutations that resulted in a truncated UmuD′ protein, and the remaining nine were missense alterations. In addition to the hydroxylamine-generated mutants, we have subcloned the mutations found in three chromosomal umuD1, umuD44, and umuD77 alleles into umuD′. All 17 umuD′ mutants resulted in lower levels of SOS-dependent spontaneous mutagenesis but varied in the extent to which they promoted methyl methanesulfonate-induced mutagenesis. We have attempted to correlate these phenotypes with the potential effect of each mutation on the recently described structure of UmuD′. PMID:9721309

  18. Enhancement of allele discrimination by introduction of nucleotide mismatches into siRNA in allele-specific gene silencing by RNAi.

    Directory of Open Access Journals (Sweden)

    Yusuke Ohnishi

    Full Text Available Allele-specific gene silencing by RNA interference (RNAi is therapeutically useful for specifically inhibiting the expression of disease-associated alleles without suppressing the expression of corresponding wild-type alleles. To realize such allele-specific RNAi (ASP-RNAi, the design and assessment of small interfering RNA (siRNA duplexes conferring ASP-RNAi is vital; however, it is also difficult. In a previous study, we developed an assay system to assess ASP-RNAi with mutant and wild-type reporter alleles encoding the Photinus and Renilla luciferase genes. In line with experiments using the system, we realized that it is necessary and important to enhance allele discrimination between mutant and corresponding wild-type alleles. Here, we describe the improvement of ASP-RNAi against mutant alleles carrying single nucleotide variations by introducing base substitutions into siRNA sequences, where original variations are present in the central position. Artificially mismatched siRNAs or short-hairpin RNAs (shRNAs against mutant alleles of the human Prion Protein (PRNP gene, which appear to be associated with susceptibility to prion diseases, were examined using this assessment system. The data indicates that introduction of a one-base mismatch into the siRNAs and shRNAs was able to enhance discrimination between the mutant and wild-type alleles. Interestingly, the introduced mismatches that conferred marked improvement in ASP-RNAi, appeared to be largely present in the guide siRNA elements, corresponding to the 'seed region' of microRNAs. Due to the essential role of the 'seed region' of microRNAs in their association with target RNAs, it is conceivable that disruption of the base-pairing interactions in the corresponding seed region, as well as the central position (involved in cleavage of target RNAs, of guide siRNA elements could influence allele discrimination. In addition, we also suggest that nucleotide mismatches at the 3'-ends of sense

  19. Recombination-deficient mutants of Bacillus subtilis

    International Nuclear Information System (INIS)

    Sadaie, Y.; Kada, T.

    1976-01-01

    Two mutant strains of Bacillus subtilis Marburg, NIG43 and NIG45, were isolated. They showed high sensitivities to gamma rays, ultraviolet light (uv), and chemicals. Deficiencies in genetic recombination of these two mutants were shown by the experiments on their capacity in transformation, SPO2 transfection, and PBS1 phage transduction, as well as on their radiation and drug sensitivities and their Hcr + capacity for uv-exposed phage M2. Some of these characteristics were compared with those of the known strains possessing the recA1 or recB2 alleles. Mapping studies revealed that the mutation rec-43 of strain NIG43 lies in the region of chromosome replication origin. The order was purA dna-8132 rec-43. Another mutation, rec-45, of strain NIG45 was found to be tightly linked to recA1. The mutation rec-43 reduced mainly the frequency of PBS1 transduction. On the other hand, the mutation rec-45 reduced the frequency of recombination involved both in transformation and PBS1 tranduction. The mutation rec-43 of strain NIG43 is conditional, but rec-45 of strain NIG45 is not. The uv impairment in cellular survival of strain NIG43 was gradually reverted at higher salt or sucrose concentrations, suggesting cellular possession of a mutated gene product whose function is conditional. In contrast to several other recombination-deficient strains, SPO2 lysogens of strains NIG43 and NIG45 were not inducible, indicating involvement of rec-43 + or rec-45 + gene product in the development of SPO2 prophage to a vegetative form. The uv-induced deoxyribonucleic acid degradation in vegetative cells was higher in rec-43 and rec-45 strains

  20. Modeling of C/EBPalpha mutant acute myeloid leukemia reveals a common expression signature of committed myeloid leukemia-initiating cells

    DEFF Research Database (Denmark)

    Kirstetter, Peggy; Schuster, Mikkel B; Bereshchenko, Oksana

    2008-01-01

    Mutations in the CEBPA gene are present in 7%-10% of human patients with acute myeloid leukemia (AML). However, no genetic models exist that demonstrate their etiological relevance. To mimic the most common mutations affecting CEBPA-that is, those leading to loss of the 42 kDa C/EBPalpha isoform (p...... penetrance. p42-deficient leukemia could be transferred by a Mac1+c-Kit+ population that gave rise only to myeloid cells in recipient mice. Expression profiling of this population against normal Mac1+c-Kit+ progenitors revealed a signature shared with MLL-AF9-transformed AML.......42) while retaining the 30kDa isoform (p30)-we modified the mouse Cebpa locus to express only p30. p30 supported the formation of granulocyte-macrophage progenitors. However, p42 was required for control of myeloid progenitor proliferation, and p42-deficient mice developed AML with complete...

  1. Allele coding in genomic evaluation

    Directory of Open Access Journals (Sweden)

    Christensen Ole F

    2011-06-01

    Full Text Available Abstract Background Genomic data are used in animal breeding to assist genetic evaluation. Several models to estimate genomic breeding values have been studied. In general, two approaches have been used. One approach estimates the marker effects first and then, genomic breeding values are obtained by summing marker effects. In the second approach, genomic breeding values are estimated directly using an equivalent model with a genomic relationship matrix. Allele coding is the method chosen to assign values to the regression coefficients in the statistical model. A common allele coding is zero for the homozygous genotype of the first allele, one for the heterozygote, and two for the homozygous genotype for the other allele. Another common allele coding changes these regression coefficients by subtracting a value from each marker such that the mean of regression coefficients is zero within each marker. We call this centered allele coding. This study considered effects of different allele coding methods on inference. Both marker-based and equivalent models were considered, and restricted maximum likelihood and Bayesian methods were used in inference. Results Theoretical derivations showed that parameter estimates and estimated marker effects in marker-based models are the same irrespective of the allele coding, provided that the model has a fixed general mean. For the equivalent models, the same results hold, even though different allele coding methods lead to different genomic relationship matrices. Calculated genomic breeding values are independent of allele coding when the estimate of the general mean is included into the values. Reliabilities of estimated genomic breeding values calculated using elements of the inverse of the coefficient matrix depend on the allele coding because different allele coding methods imply different models. Finally, allele coding affects the mixing of Markov chain Monte Carlo algorithms, with the centered coding being

  2. Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 3. Effects of Aging in Various Genotypes

    International Nuclear Information System (INIS)

    Balchiuniene, L.

    1995-01-01

    Gamma-irradiation effect was tested on the grain material of normal-initial barley c. 'Auksiniai II' and allelic mutants tw 1 and tw 2 . Dependence of the aging effects on genotype was obvious, especially in survival test. Differences were observed even on allelic mutants. These observations are important for the preservation strategy of plant genetical resources. (author). 11 refs., 3 tabs

  3. miRNA and Degradome Sequencing Reveal miRNA and Their Target Genes That May Mediate Shoot Growth in Spur Type Mutant “Yanfu 6”

    Science.gov (United States)

    Song, Chunhui; Zhang, Dong; Zheng, Liwei; Zhang, Jie; Zhang, Baojuan; Luo, Wenwen; Li, Youmei; Li, Guangfang; Ma, Juanjuan; Han, Mingyu

    2017-01-01

    The spur-type growth habit in apple trees is characterized by short internodes, increased number of fruiting spurs, and compact growth that promotes flowering and facilitates management practices, such as pruning. The molecular mechanisms responsible for regulating spur-type growth have not been elucidated. In the present study, miRNAs and the expression of their potential target genes were evaluated in shoot tips of “Nagafu 2” (CF) and spur-type bud mutation “Yanfu 6” (YF). A total of 700 mature miRNAs were identified, including 202 known apple miRNAs and 498 potential novel miRNA candidates. A comparison of miRNA expression in CF and YF revealed 135 differentially expressed genes, most of which were downregulated in YF. YF also had lower levels of GA, ZR, IAA, and ABA hormones, relative to CF. Exogenous applications of GA promoted YF shoot growth. Based on the obtained results, a regulatory network involving plant hormones, miRNA, and their potential target genes is proposed for the molecular mechanism regulating the growth of YF. miRNA164, miRNA166, miRNA171, and their potential targets, and associated plant hormones, appear to regulate shoot apical meristem (SAM) growth. miRNA159, miRNA167, miRNA396, and their potential targets, and associated plant hormones appear to regulate cell division and internode length. This study provides a foundation for further studies designed to elucidate the mechanism underlying spur-type apple architecture. PMID:28424721

  4. Allele coding in genomic evaluation

    DEFF Research Database (Denmark)

    Standen, Ismo; Christensen, Ole Fredslund

    2011-01-01

    Genomic data are used in animal breeding to assist genetic evaluation. Several models to estimate genomic breeding values have been studied. In general, two approaches have been used. One approach estimates the marker effects first and then, genomic breeding values are obtained by summing marker...... effects. In the second approach, genomic breeding values are estimated directly using an equivalent model with a genomic relationship matrix. Allele coding is the method chosen to assign values to the regression coefficients in the statistical model. A common allele coding is zero for the homozygous...... genotype of the first allele, one for the heterozygote, and two for the homozygous genotype for the other allele. Another common allele coding changes these regression coefficients by subtracting a value from each marker such that the mean of regression coefficients is zero within each marker. We call...

  5. Genetics of dwarfness in induced mutants of hexaploid triticale and its response to exogenous GA3

    International Nuclear Information System (INIS)

    Reddy, V.D.; Reddy, G.M.

    1991-01-01

    Genetics of dwarfism in two induced mutant (d 1 and d 2 ) of hexaploid triticale, DTS 330, revealed that this trait is governed by single recessive gene. Both d 1 and d 2 were allelic to each other and d 1 was dominant over d 2 . Both d 1 , d 2 and their F 1 showed no response to exogenous GA 3 , whereas, DTS 330, d 1 x DTS 330 and d 2 x DTS 330 were responsive. The endogenous levels of GA 3 were more in the dwarf mutants than control, suggesting that dwarfness in these may be due to a partial block in the GA utilizing mechanism, rather than a block in GA biosynthesis. (author). 5 refs., 2 tabs

  6. Genetic analyses of nonfluorescent root mutants induced by mutagenesis in soybean

    International Nuclear Information System (INIS)

    Sawada, S.; Palmer, R.G.

    1987-01-01

    Nonfluorescent root mutants in soybean [Glycine max (L.) Merr.] are useful as markers in genetic studies and in tissue culture research. Our objective was to obtain mutagen-induced nonfluorescent root mutants and to conduct genetic studies with them. Thirteen nonfluorescent mutants were detected among 154016 seedlings derived from soybean lines treated with six mutagens. One of these mutants, derived from Williams treated with 20 kR gamma rays, did not correspond to any of the known (standard) nonfluorescent spontaneous mutants. This is the first mutagen-induced nonfluorescent root mutant in soybean. It was assigned Genetic Type Collection no. T285 and the gene symbol fr5 fr5. The fr5 allele was not located on trisomics A, B, or C and was not linked to five chlorophyll-deficient mutants (y9, y11, y12, y13, and y20-k2) or flower color mutant w1. The remaining nonfluorescent root mutants were at the same loci as known spontaneous mutants; i.e., four had the fr1 allele, five had the fr2 allele, and three had the fr4 allele

  7. A strategy to discover genes that carry multi-allelic or mono-allelic risk for common diseases: A cohort allelic sums test (CAST)

    International Nuclear Information System (INIS)

    Morgenthaler, Stephan; Thilly, William G.

    2007-01-01

    A method is described to discover if a gene carries one or more allelic mutations that confer risk for any specified common disease. The method does not depend upon genetic linkage of risk-conferring mutations to high frequency genetic markers such as single nucleotide polymorphisms. Instead, the sums of allelic mutation frequencies in case and control cohorts are determined and a statistical test is applied to discover if the difference in these sums is greater than would be expected by chance. A statistical model is presented that defines the ability of such tests to detect significant gene-disease relationships as a function of case and control cohort sizes and key confounding variables: zygosity and genicity, environmental risk factors, errors in diagnosis, limits to mutant detection, linkage of neutral and risk-conferring mutations, ethnic diversity in the general population and the expectation that among all exonic mutants in the human genome greater than 90% will be neutral with regard to any effect on disease risk. Means to test the null hypothesis for, and determine the statistical power of, each test are provided. For this 'cohort allelic sums test' or 'CAST', the statistical model and test are provided as an Excel (TM) program, CASTAT (C) at http://epidemiology.mit.edu. Based on genetics, technology and statistics, a strategy of enumerating the mutant alleles carried in the exons and splice sites of the estimated ∼25,000 human genes in case cohort samples of 10,000 persons for each of 100 common diseases is proposed and evaluated: A wide range of possible conditions of multi-allelic or mono-allelic and monogenic, multigenic or polygenic (including epistatic) risk are found to be detectable using the statistical criteria of 1 or 10 ''false positive'' gene associations per 25,000 gene-disease pair-wise trials and a statistical power of >0.8. Using estimates of the distribution of both neutral and gene-inactivating nondeleterious mutations in humans and

  8. A novel Gerstmann-Sträussler-Scheinker disease mutation defines a precursor for amyloidogenic 8 kDa PrP fragments and reveals N-terminal structural changes shared by other GSS alleles

    Science.gov (United States)

    Mercer, Robert C. C.; Fu, Ze-Lin; Mays, Charles E.; Gapeshina, Hristina; Wohlgemuth, Serene L.; Acevedo-Morantes, Claudia Y.; Cashman, Neil R.; Coulthart, Michael B.; Jansen, Gerard H.; Stepanova, Maria

    2018-01-01

    To explore pathogenesis in a young Gerstmann-Sträussler-Scheinker Disease (GSS) patient, the corresponding mutation, an eight-residue duplication in the hydrophobic region (HR), was inserted into the wild type mouse PrP gene. Transgenic (Tg) mouse lines expressing this mutation (Tg.HRdup) developed spontaneous neurologic syndromes and brain extracts hastened disease in low-expressor Tg.HRdup mice, suggesting de novo formation of prions. While Tg.HRdup mice exhibited spongiform change, PrP aggregates and the anticipated GSS hallmark of a proteinase K (PK)-resistant 8 kDa fragment deriving from the center of PrP, the LGGLGGYV insertion also imparted alterations in PrP's unstructured N-terminus, resulting in a 16 kDa species following thermolysin exposure. This species comprises a plausible precursor to the 8 kDa PK-resistant fragment and its detection in adolescent Tg.HRdup mice suggests that an early start to accumulation could account for early disease of the index case. A 16 kDa thermolysin-resistant signature was also found in GSS patients with P102L, A117V, H187R and F198S alleles and has coordinates similar to GSS stop codon mutations. Our data suggest a novel shared pathway of GSS pathogenesis that is fundamentally distinct from that producing structural alterations in the C-terminus of PrP, as observed in other prion diseases such as Creutzfeldt-Jakob Disease and scrapie. PMID:29338055

  9. Development and characterization of mutant winter wheat (Triticum aestivum L.) accessions resistant to the herbicide quizalofop.

    Science.gov (United States)

    Ostlie, Michael; Haley, Scott D; Anderson, Victoria; Shaner, Dale; Manmathan, Harish; Beil, Craig; Westra, Phillip

    2015-02-01

    New herbicide resistance traits in wheat were produced through the use of induced mutagenesis. While herbicide-resistant crops have become common in many agricultural systems, wheat has seen few introductions of herbicide resistance traits. A population of Hatcher winter wheat treated with ethyl methanesulfonate was screened with quizalofop to identify herbicide-resistant plants. Initial testing identified plants that survived multiple quizalofop applications. A series of experiments were designed to characterize this trait. In greenhouse studies the mutants exhibited high levels of quizalofop resistance compared to non-mutant wheat. Sequencing ACC1 revealed a novel missense mutation causing an alanine to valine change at position 2004 (Alopecurus myosuroides reference sequence). Plants carrying single mutations in wheat's three genomes (A, B, D) were identified. Acetyl co-enzyme A carboxylase in resistant plants was 4- to 10-fold more tolerant to quizalofop. Populations of segregating backcross progenies were developed by crossing each of the three individual mutants with wild-type wheat. Experiments conducted with these populations confirmed largely normal segregation, with each mutant allele conferring an additive level of resistance. Further tests showed that the A genome mutation conferred the greatest resistance and the B genome mutation conferred the least resistance to quizalofop. The non-transgenic herbicide resistance trait identified will enhance weed control strategies in wheat.

  10. A Reverse-Genetics Mutational Analysis of the Barley HvDWARF Gene Results in Identification of a Series of Alleles and Mutants with Short Stature of Various Degree and Disturbance in BR Biosynthesis Allowing a New Insight into the Process.

    Science.gov (United States)

    Gruszka, Damian; Gorniak, Malgorzata; Glodowska, Ewelina; Wierus, Ewa; Oklestkova, Jana; Janeczko, Anna; Maluszynski, Miroslaw; Szarejko, Iwona

    2016-04-22

    Brassinosteroids (BRs) are plant steroid hormones, regulating a broad range of physiological processes. The largest amount of data related with BR biosynthesis has been gathered in Arabidopsis thaliana, however understanding of this process is far less elucidated in monocot crops. Up to now, only four barley genes implicated in BR biosynthesis have been identified. Two of them, HvDWARF and HvBRD, encode BR-6-oxidases catalyzing biosynthesis of castasterone, but their relation is not yet understood. In the present study, the identification of the HvDWARF genomic sequence, its mutational and functional analysis and characterization of new mutants are reported. Various types of mutations located in different positions within functional domains were identified and characterized. Analysis of their impact on phenotype of the mutants was performed. The identified homozygous mutants show reduced height of various degree and disrupted skotomorphogenesis. Mutational analysis of the HvDWARF gene with the "reverse genetics" approach allowed for its detailed functional analysis at the level of protein functional domains. The HvDWARF gene function and mutants' phenotypes were also validated by measurement of endogenous BR concentration. These results allowed a new insight into the BR biosynthesis in barley.

  11. Delimiting Allelic Imbalance of TYMS by Allele-Specific Analysis.

    Science.gov (United States)

    Balboa-Beltrán, Emilia; Cruz, Raquel; Carracedo, Angel; Barros, Francisco

    2015-07-01

    Allelic imbalance of thymidylate synthase (TYMS) is attributed to polymorphisms in the 5'- and 3'-untranslated region (UTR). These polymorphisms have been related to the risk of suffering different cancers, for example leukemia, breast or gastric cancer, and response to different drugs, among which are methotrexate glutamates, stavudine, and specifically 5-fluorouracil (5-FU), as TYMS is its direct target. A vast literature has been published in relation to 5-FU, even suggesting the sole use of these polymorphisms to effectively manage 5-FU dosage. Estimates of the extent to which these polymorphisms influence in TYMS expression have in the past been based on functional analysis by luciferase assays and quantification of TYMS mRNA, but both these studies, as the association studies with cancer risk or with toxicity or response to 5-FU, are very contradictory. Regarding functional assays, the artificial genetic environment created in luciferase assay and the problems derived from quantitative polymerase chain reactions (qPCRs), for example the use of a reference gene, may have distorted the results. To avoid these sources of interference, we have analyzed the allelic imbalance of TYMS by allelic-specific analysis in peripheral blood mononuclear cells (PBMCs) from patients.Allelic imbalance in PBMCs, taken from 40 patients with suspected myeloproliferative haematological diseases, was determined by fluorescent fragment analysis (for the 3'-UTR polymorphism), Sanger sequencing and allelic-specific qPCR in multiplex (for the 5'-UTR polymorphisms).For neither the 3'- nor the 5'-UTR polymorphisms did the observed allelic imbalance exceed 1.5 fold. None of the TYMS polymorphisms is statistically associated with allelic imbalance.The results acquired allow us to deny the previously established assertion of an influence of 2 to 4 fold of the rs45445694 and rs2853542 polymorphisms in the expression of TYMS and narrow its allelic imbalance to 1.5 fold, in our population

  12. Systematic Functional Interrogation of Rare Cancer Variants Identifies Oncogenic Alleles | Office of Cancer Genomics

    Science.gov (United States)

    Cancer genome characterization efforts now provide an initial view of the somatic alterations in primary tumors. However, most point mutations occur at low frequency, and the function of these alleles remains undefined. We have developed a scalable systematic approach to interrogate the function of cancer-associated gene variants. We subjected 474 mutant alleles curated from 5,338 tumors to pooled in vivo tumor formation assays and gene expression profiling. We identified 12 transforming alleles, including two in genes (PIK3CB, POT1) that have not been shown to be tumorigenic.

  13. Characterization of novel Sorghum brown midrib mutants from an EMS-mutagenized population.

    Science.gov (United States)

    Sattler, Scott E; Saballos, Ana; Xin, Zhanguo; Funnell-Harris, Deanna L; Vermerris, Wilfred; Pedersen, Jeffrey F

    2014-09-02

    Reducing lignin concentration in lignocellulosic biomass can increase forage digestibility for ruminant livestock and saccharification yields of biomass for bioenergy. In sorghum (Sorghum bicolor (L.) Moench) and several other C4 grasses, brown midrib (bmr) mutants have been shown to reduce lignin concentration. Putative bmr mutants isolated from an EMS-mutagenized population were characterized and classified based on their leaf midrib phenotype and allelism tests with the previously described sorghum bmr mutants bmr2, bmr6, and bmr12. These tests resulted in the identification of additional alleles of bmr2, bmr6, and bmr12, and, in addition, six bmr mutants were identified that were not allelic to these previously described loci. Further allelism testing among these six bmr mutants showed that they represented four novel bmr loci. Based on this study, the number of bmr loci uncovered in sorghum has doubled. The impact of these lines on agronomic traits and lignocellulosic composition was assessed in a 2-yr field study. Overall, most of the identified bmr lines showed reduced lignin concentration of their biomass relative to wild-type (WT). Effects of the six new bmr mutants on enzymatic saccharification of lignocellulosic materials were determined, but the amount of glucose released from the stover was similar to WT in all cases. Like bmr2, bmr6, and bmr12, these mutants may affect monolignol biosynthesis and may be useful for bioenergy and forage improvement when stacked together or in combination with the three previously described bmr alleles. Copyright © 2014 Sattler et al.

  14. Isolation and characterization of MMS-sensitive mutants of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Prakash, L.; Prakash, S.

    1977-01-01

    We have isolated mutants sensitive to methyl methanesulfonate (MMS) in Saccharomyces cerevisiae. Alleles of rad1, rad4, rad6, rad52, rad55 and rad57 were found among these mms mutants. Twenty-nine of the mms mutants which complement the existing radiation-sensitive (rad and rev) mutants belong to 22 new complementation groups. Mutants from five complementation groups are sensitive only to MMS. Mutants of 11 complementation groups are sensitive to uv or x rays in addition to MMS, mutants of six complementation groups are sensitive to all three agents. The cross-sensitivities of these mms mutants to uv and x rays are discussed in terms of their possible involvement in DNA repair. Sporulation is reduced or absent in homozygous diploids of mms mutants from nine complementation groups

  15. A series of N-terminal epitope tagged Hdh knock-in alleles expressing normal and mutant huntingtin: their application to understanding the effect of increasing the length of normal huntingtin’s polyglutamine stretch on CAG140 mouse model pathogenesis

    Directory of Open Access Journals (Sweden)

    Zheng Shuqiu

    2012-08-01

    Full Text Available Abstract Background Huntington’s disease (HD is an autosomal dominant neurodegenerative disease that is caused by the expansion of a polyglutamine (polyQ stretch within Huntingtin (htt, the protein product of the HD gene. Although studies in vitro have suggested that the mutant htt can act in a potentially dominant negative fashion by sequestering wild-type htt into insoluble protein aggregates, the role of the length of the normal htt polyQ stretch, and the adjacent proline-rich region (PRR in modulating HD mouse model pathogenesis is currently unknown. Results We describe the generation and characterization of a series of knock-in HD mouse models that express versions of the mouse HD gene (Hdh encoding N-terminal hemaglutinin (HA or 3xFlag epitope tagged full-length htt with different polyQ lengths (HA7Q-, 3xFlag7Q-, 3xFlag20Q-, and 3xFlag140Q-htt and substitution of the adjacent mouse PRR with the human PRR (3xFlag20Q- and 3xFlag140Q-htt. Using co-immunoprecipitation and immunohistochemistry analyses, we detect no significant interaction between soluble full-length normal 7Q- htt and mutant (140Q htt, but we do observe N-terminal fragments of epitope-tagged normal htt in mutant htt aggregates. When the sequences encoding normal mouse htt’s polyQ stretch and PRR are replaced with non-pathogenic human sequence in mice also expressing 140Q-htt, aggregation foci within the striatum, and the mean size of htt inclusions are increased, along with an increase in striatal lipofuscin and gliosis. Conclusion In mice, soluble full-length normal and mutant htt are predominantly monomeric. In heterozygous knock-in HD mouse models, substituting the normal mouse polyQ and PRR with normal human sequence can exacerbate some neuropathological phenotypes.

  16. Distribution of a pseudodeficiency allele among Tay-Sachs carriers

    Energy Technology Data Exchange (ETDEWEB)

    Tomczak, J.; Grebner, E.E. (Thomas Jefferson Univ., Philadelphia, PA (United States)); Boogen, C. (Univ. of Essen Medical School (Germany))

    1993-08-01

    Recently Triggs-Raine et al. (1992) identified a new mutation in the gene coding for the [alpha]-subunit of [beta]-hexosaminidase A (hex A), the enzyme whose deficiency causes Tay-Sachs disease. This mutation, a C[sub 739]-to-T transition in exon 7, results in an altered enzyme that is active (albeit at reduced levels) in cells but that has essentially no activity in serum. This so-called pseudodeficient allele was first detected in compound heterozygotes who also carried a Tay-Sachs disease allele and therefore had no detectable hex A in their serum but who were in good health. Carriers of this apparently benign mutation are generally indistinguishable from carriers of a lethal mutation by means of routine enzyme-based screening tests, because the product of the pseudodeficient allele is not detectable in serum and has decreased activity in cells. This suggests that some individuals who have been classified as Tay-Sachs carriers are actually carriers of the pseudodeficient allele and are not at risk to have a child affected with Tay-Sachs disease. The pseudodeficient allele may also be responsible for some inconclusive diagnoses, where leukocyte values fall below the normal range but are still above the carrier range. The fact that there are now two mutant alleles (the psuedodeficient and the adult) that are indistinguishable from the lethal infantile mutations by means of enzyme assay yet that are phenotypically very different and that together may account for as much as 12% of enzyme-defined carriers on the basis of the data here suggests that DNA analysis should be part of a comprehensive screening program. It will be particularly useful to identify the mutations in couples at risk, before they undergo prenatal diagnosis. DNA analysis will also resolve some inconclusive diagnoses.

  17. ARID1B is a specific vulnerability in ARID1A-mutant cancers.

    Science.gov (United States)

    Helming, Katherine C; Wang, Xiaofeng; Wilson, Boris G; Vazquez, Francisca; Haswell, Jeffrey R; Manchester, Haley E; Kim, Youngha; Kryukov, Gregory V; Ghandi, Mahmoud; Aguirre, Andrew J; Jagani, Zainab; Wang, Zhong; Garraway, Levi A; Hahn, William C; Roberts, Charles W M

    2014-03-01

    Recent studies have revealed that ARID1A, encoding AT-rich interactive domain 1A (SWI-like), is frequently mutated across a variety of human cancers and also has bona fide tumor suppressor properties. Consequently, identification of vulnerabilities conferred by ARID1A mutation would have major relevance for human cancer. Here, using a broad screening approach, we identify ARID1B, an ARID1A homolog whose gene product is mutually exclusive with ARID1A in SWI/SNF complexes, as the number 1 gene preferentially required for the survival of ARID1A-mutant cancer cell lines. We show that loss of ARID1B in ARID1A-deficient backgrounds destabilizes SWI/SNF and impairs proliferation in both cancer cells and primary cells. We also find that ARID1A and ARID1B are frequently co-mutated in cancer but that ARID1A-deficient cancers retain at least one functional ARID1B allele. These results suggest that loss of ARID1A and ARID1B alleles cooperatively promotes cancer formation but also results in a unique functional dependence. The results further identify ARID1B as a potential therapeutic target for ARID1A-mutant cancers.

  18. In Vivo-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic penA Alleles That Confer Ceftriaxone Resistance in Neisseria gonorrhoeae.

    Science.gov (United States)

    Vincent, Leah R; Kerr, Samuel R; Tan, Yang; Tomberg, Joshua; Raterman, Erica L; Dunning Hotopp, Julie C; Unemo, Magnus; Nicholas, Robert A; Jerse, Ann E

    2018-04-03

    Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cro r ) clinical isolates (H041 and F89) into a Cro s strain (FA19) by allelic exchange and showed that the resultant Cro r mutants were significantly outcompeted by the Cro s parent strain in vitro and in a murine infection model. Four Cro r compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnB G348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19 penA41 acnB G348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cro r gonococcal strains that increase metabolism to ameliorate their fitness deficit. IMPORTANCE The emergence of ceftriaxone-resistant (Cro r ) Neisseria gonorrhoeae has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of

  19. A Medicago truncatula rdr6 allele impairs transgene silencing and endogenous phased siRNA production but not development.

    Science.gov (United States)

    Bustos-Sanmamed, Pilar; Hudik, Elodie; Laffont, Carole; Reynes, Christelle; Sallet, Erika; Wen, Jiangqi; Mysore, Kirankumar S; Camproux, Anne-Claude; Hartmann, Caroline; Gouzy, Jérome; Frugier, Florian; Crespi, Martin; Lelandais-Brière, Christine

    2014-12-01

    RNA-dependent RNA polymerase 6 (RDR6) and suppressor of gene silencing 3 (SGS3) act together in post-transcriptional transgene silencing mediated by small interfering RNAs (siRNAs) and in biogenesis of various endogenous siRNAs including the tasiARFs, known regulators of auxin responses and plant development. Legumes, the third major crop family worldwide, has been widely improved through transgenic approaches. Here, we isolated rdr6 and sgs3 mutants in the model legume Medicago truncatula. Two sgs3 and one rdr6 alleles led to strong developmental defects and impaired biogenesis of tasiARFs. In contrast, the rdr6.1 homozygous plants produced sufficient amounts of tasiARFs to ensure proper development. High throughput sequencing of small RNAs from this specific mutant identified 354 potential MtRDR6 substrates, for which siRNA production was significantly reduced in the mutant. Among them, we found a large variety of novel phased loci corresponding to protein-encoding genes or transposable elements. Interestingly, measurement of GFP expression revealed that post-transcriptional transgene silencing was reduced in rdr6.1 roots. Hence, this novel mis-sense mutation, affecting a highly conserved amino acid residue in plant RDR6s, may be an interesting tool both to analyse endogenous pha-siRNA functions and to improve transgene expression, at least in legume species. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  20. Is auxin involved in the induction of genetic instability in barley homeotic double mutants?

    Science.gov (United States)

    Šiukšta, Raimondas; Vaitkūnienė, Virginija; Rančelis, Vytautas

    2018-02-01

    The triggers of genetic instability in barley homeotic double mutants are tweaky spike -type mutations associated with an auxin imbalance in separate spike phytomeres. Barley homeotic tweaky spike;Hooded (tw;Hd) double mutants are characterized by an inherited instability of spike and flower development, which is absent in the single parental constituents. The aim of the present study was to show that the trigger of genetic instability in the double mutants is the tw mutations, which are associated with an auxin imbalance in the developing spikes. Their pleiotropic effects on genes related to spike/flower development may cause the genetic instability of double mutants. The study of four double-mutant groups composed of different mutant alleles showed that the instability arose only if the mutant allele tw was a constituent of the double mutants. Application of auxin inhibitors and 2,4-dichlorophenoxyacetic acid (2,4-D) demonstrated the relationship of the instability of the double mutants and the phenotype of the tw mutants to auxin imbalance. 2,4-D induced phenocopies of the tw mutation in wild-type plants and rescued the phenotypes of three allelic tw mutants. The differential display (dd-PCR) method allowed the identification of several putative candidate genes in tw that may be responsible for the initiation of instability in the double mutants by pleiotropic variations of their expression in the tw mutant associated with auxin imbalance in the developing spikes. The results of the present study linked the genetic instability of homeotic double mutants with an auxin imbalance caused by one of the constituents (tw). The genetic instability of the double mutants in relation to auxin imbalance was studied for the first time. A matrocliny on instability expression was also observed.

  1. Isolation of a novel UVB-tolerant rice mutant obtained by exposure to carbon-ion beams.

    Science.gov (United States)

    Takano, Nao; Takahashi, Yuko; Yamamoto, Mitsuru; Teranishi, Mika; Yamaguchi, Hiroko; Sakamoto, Ayako N; Hase, Yoshihiro; Fujisawa, Hiroko; Wu, Jianzhong; Matsumoto, Takashi; Toki, Seiichi; Hidema, Jun

    2013-07-01

    UVB radiation suppresses photosynthesis and protein biosynthesis in plants, which in turn decreases growth and productivity. Here, an ultraviolet-B (UVB)-tolerant rice mutant, utr319 (UV Tolerant Rice 319), was isolated from a mutagenized population derived from 2500 M1 seeds (of the UVB-resistant cultivar 'Sasanishiki') that were exposed to carbon ions. The utr319 mutant was more tolerant to UVB than the wild type. Neither the levels of UVB-induced cyclobutane pyrimidine dimers (CPDs) or (6-4) pyrimidine-pyrimidone photodimers [(6-4) photoproducts], nor the repair of CPDs or (6-4) photoproducts, was altered in the utr319 mutant. Thus, the utr319 mutant may be impaired in the production of a previously unidentified factor that confers UVB tolerance. To identify the mutated region in the utr319 mutant, microarray-based comparative genomic hybridization analysis was performed. Two adjacent genes on chromosome 7, Os07g0264900 and Os07g0265100, were predicted to represent the mutant allele. Sequence analysis of the chromosome region in utr319 revealed a deletion of 45 419 bp. RNAi analysis indicated that Os07g0265100 is most likely the mutated gene. Database analysis indicated that the Os07g0265100 gene, UTR319, encodes a putative protein with unknown characteristics or function. In addition, the homologs of UTR319 are conserved only among land plants. Therefore, utr319 is a novel UVB-tolerant rice mutant and UTR319 may be crucial for the determination of UVB sensitivity in rice, although the function of UTR319 has not yet been determined.

  2. Isolation of a novel UVB-tolerant rice mutant obtained by exposure to carbon-ion beams

    International Nuclear Information System (INIS)

    Takano, Nao; Takahashi, Yuko; Yamamoto, Mitsuru; Teranishi, Mika; Yamaguchi, Hiroko; Sakamoto, Ayako N.; Hase, Yoshihiro; Fujisawa, Hiroko; Wu, Jianzhong; Matsumoto, Takashi; Toki, Seiichi; Hidema, Jun

    2013-01-01

    UVB radiation suppresses photosynthesis and protein biosynthesis in plants, which in turn decreases growth and productivity. Here, an ultraviolet-B (UVB)-tolerant rice mutant, utr319 (UVTolerantRice319), was isolated from a mutagenized population derived from 2500 M 1 seeds (of the UVB-resistant cultivar ‘Sasanishiki’) that were exposed to carbon ions. The utr319 mutant was more tolerant to UVB than the wild type. Neither the levels of UVB-induced cyclobutane pyrimidine dimers (CPDs) or (6-4) pyrimidine-pyrimidone photodimers [(6-4) photoproducts], nor the repair of CPDs or (6-4) photoproducts, was altered in the utr319 mutant. Thus, the utr319 mutant may be impaired in the production of a previously unidentified factor that confers UVB tolerance. To identify the mutated region in the utr319 mutant, microarray-based comparative genomic hybridization analysis was performed. Two adjacent genes on chromosome 7, Os07g0264900 and Os07g0265100, were predicted to represent the mutant allele. Sequence analysis of the chromosome region in utr319 revealed a deletion of 45 419 bp. RNAi analysis indicated that Os07g0265100 is most likely the mutated gene. Database analysis indicated that the Os07g0265100 gene, UTR319, encodes a putative protein with unknown characteristics or function. In addition, the homologs of UTR319 are conserved only among land plants. Therefore, utr319 is a novel UVB-tolerant rice mutant and UTR319 may be crucial for the determination of UVB sensitivity in rice, although the function of UTR319 has not yet been determined

  3. Analysis of fast neutron-generated mutants at the Arabidopsis thaliana HY4 locus

    International Nuclear Information System (INIS)

    Bruggemann, E.; Handwerger, K.; Essex, C.; Storz, G.

    1996-01-01

    Ionizing radiation is expected to produce mutants with deletions or other chromosomal rearrangements. These mutants are useful for a variety of purposes, such as creating null alleles and cloning genes whose existence is known only from their mutant phenotype; however, only a few mutations generated by ionizing radiation have been characterized at the molecular level in Arabidopsis thaliana. Twenty fast neutron-generated alleles of the Arabidopsis HY4 locus, which encodes a blue light receptor, CRY1, were isolated and characterized. Nine of the mutant alleles displayed normal genetic behavior. The other 11 mutant alleles were poorly transmitted through the male gametophyte and were lethal in homozygous plants. Southern blot analysis demonstrated that alleles of the first group generally contain small or moderate-sized deletions at HY4, while alleles of the second group contain large deletions at this locus. These results demonstrate that fast neutrons can produce a range of deletions at a single locus in Arabidopsis. Many of these deletions would be suitable for cloning by genomic subtraction or representational difference analysis. The results also suggest the presence of an essential locus adjacent to HY4. (author)

  4. SSR allelic variation in almond (Prunus dulcis Mill.).

    Science.gov (United States)

    Xie, Hua; Sui, Yi; Chang, Feng-Qi; Xu, Yong; Ma, Rong-Cai

    2006-01-01

    Sixteen SSR markers including eight EST-SSR and eight genomic SSRs were used for genetic diversity analysis of 23 Chinese and 15 international almond cultivars. EST- and genomic SSR markers previously reported in species of Prunus, mainly peach, proved to be useful for almond genetic analysis. DNA sequences of 117 alleles of six of the 16 SSR loci were analysed to reveal sequence variation among the 38 almond accessions. For the four SSR loci with AG/CT repeats, no insertions or deletions were observed in the flanking regions of the 98 alleles sequenced. Allelic size variation of these loci resulted exclusively from differences in the structures of repeat motifs, which involved interruptions or occurrences of new motif repeats in addition to varying number of AG/CT repeats. Some alleles had a high number of uninterrupted repeat motifs, indicating that SSR mutational patterns differ among alleles at a given SSR locus within the almond species. Allelic homoplasy was observed in the SSR loci because of base substitutions, interruptions or compound repeat motifs. Substitutions in the repeat regions were found at two SSR loci, suggesting that point mutations operate on SSRs and hinder the further SSR expansion by introducing repeat interruptions to stabilize SSR loci. Furthermore, it was shown that some potential point mutations in the flanking regions are linked with new SSR repeat motif variation in almond and peach.

  5. Origin of allelic diversity in antirrhinum S locus RNases.

    Science.gov (United States)

    Xue, Y; Carpenter, R; Dickinson, H G; Coen, E S

    1996-01-01

    In many plant species, self-incompatibility (SI) is genetically controlled by a single multiallelic S locus. Previous analysis of S alleles in the Solanaceae, in which S locus ribonucleases (S RNases) are responsible for stylar expression of SI, has demonstrated that allelic diversity predated speciation within this family. To understand how allelic diversity has evolved, we investigated the molecular basis of gametophytic SI in Antirrhinum, a member of the Scrophulariaceae, which is closely related to the Solanaceae. We have characterized three Antirrhinum cDNAs encoding polypeptides homologous to S RNases and shown that they are encoded by genes at the S locus. RNA in situ hybridization revealed that the Antirrhinum S RNase are primarily expressed in the stylar transmitting tissue. This expression is consistent with their proposed role in arresting the growth of self-pollen tubes. S alleles from the Scrophulariaceae form a separate group from those of the Solanaceae, indicating that new S alleles have been generated since these families separated (approximately 40 million years). We propose that the recruitment of an ancestral RNase gene into SI occurred during an early stage of angiosperm evolution and that, since that time, new alleles subsequently have arisen at a low rate. PMID:8672882

  6. An Updated Collection of Sequence Barcoded Temperature-Sensitive Alleles of Yeast Essential Genes.

    Science.gov (United States)

    Kofoed, Megan; Milbury, Karissa L; Chiang, Jennifer H; Sinha, Sunita; Ben-Aroya, Shay; Giaever, Guri; Nislow, Corey; Hieter, Philip; Stirling, Peter C

    2015-07-14

    Systematic analyses of essential gene function using mutant collections in Saccharomyces cerevisiae have been conducted using collections of heterozygous diploids, promoter shut-off alleles, through alleles with destabilized mRNA, destabilized protein, or bearing mutations that lead to a temperature-sensitive (ts) phenotype. We previously described a method for construction of barcoded ts alleles in a systematic fashion. Here we report the completion of this collection of alleles covering 600 essential yeast genes. This resource covers a larger gene repertoire than previous collections and provides a complementary set of strains suitable for single gene and genomic analyses. We use deep sequencing to characterize the amino acid changes leading to the ts phenotype in half of the alleles. We also use high-throughput approaches to describe the relative ts behavior of the alleles. Finally, we demonstrate the experimental usefulness of the collection in a high-content, functional genomic screen for ts alleles that increase spontaneous P-body formation. By increasing the number of alleles and improving the annotation, this ts collection will serve as a community resource for probing new aspects of biology for essential yeast genes. Copyright © 2015 Kofoed et al.

  7. Genetic analysis and molecular detection of the corn endosperm mutants induced by space flight

    International Nuclear Information System (INIS)

    Zhang Caibo; Zhou Yuanyuan; Wang Hanyu; Wang Hongwei; Wang Shengqing; Rong Tingzhao; Cao Moju

    2013-01-01

    In this study, two maize inbred lines 08-641 and 18-599 were carried into cosmic space by recoverable satellite 'Shijian 8', grain shrunken transparently and opaquely mutants were selected as experimental materials and their soluble sugar content in kernel were measured by annthrone colorimetry. The content of soluble sugar in mutant st1 kernels began to rise in 10 days after pollination, to reach the peak in 25 days and significantly higher than the contrast 08-641, while in mutant sol kernels it began to rise in 10 days after pollination, to reach the peak in 20 days and significantly higher than the contrast 18-599. The results of genetic analysis and allelism test showed that the trait in both mutants was all controlled by a single recessive gene, the mutant st1 was allelic to the su1 and the mutant sol was allelic to the sh2. DNA sequence alignment found 2 single-base mutations in 2 and 13 exon of su1 gene in the mutant st1 and 3 single-base mutations in 2, 5 and 16 exon of sh2 gene in mutant so1 leading to the change in amino acid sequences. So it is inferred that starch biosynthesis in the mutants may be blocked by these mutations, which lead to the increase of soluble sugar content in kernel. (authors)

  8. Promising rice mutants

    International Nuclear Information System (INIS)

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1988-01-01

    Two induced mutants namely, Mut NS 1 (tall) and Mut NS 5 (semi-dwarf) derived from rice variety Nizersail were evaluated for various agronomic characters at four locations in Bangladesh. Both the mutants matured about three weeks earlier and yielded significantly higher than the parent variety Nizersail. (author). 3 tabs., 9 refs

  9. Analysis of Erwinia chrysanthemi EC16 pelE::uidA, pelL::uidA, and hrpN::uidA mutants reveals strain-specific atypical regulation of the Hrp type III secretion system.

    Science.gov (United States)

    Ham, Jong Hyun; Cui, Yaya; Alfano, James R; Rodríguez-Palenzuela, Pablo; Rojas, Clemencia M; Chatterjee, Arun K; Collmer, Alan

    2004-02-01

    The plant pathogen Erwinia chrysanthemi produces a variety of factors that have been implicated in its ability to cause soft-rot diseases in various hosts. These include HrpN, a harpin secreted by the Hrp type III secretion system; PelE, one of several major pectate lyase isozymes secreted by the type II system; and PelL, one of several secondary Pels secreted by the type II system. We investigated these factors in E. chrysanthemi EC16 with respect to the effects of medium composition and growth phase on gene expression (as determined with uidA fusions and Northern analyses) and effects on virulence. pelE was induced by polygalacturonic acid, but pelL was not, and hrpN was expressed unexpectedly in nutrient-rich King's medium B and in minimal salts medium at neutral pH. In contrast, the effect of medium composition on hrp expression in E. chrysanthemi CUCPB1237 and 3937 was like that of many other phytopathogenic bacteria in being repressed in complex media and induced in acidic pH minimal medium. Northern blot analysis of hrpN and hrpL expression by the wild-type and hrpL::omegaCmr and hrpS::omegaCmr mutants revealed that hrpN expression was dependent on the HrpL alternative sigma factor, whose expression, in turn, was dependent on the HrpS putative sigma54 enhancer binding protein. The expression of pelE and hrpN increased strongly in late logarithmic growth phase. To test the possible role of quorum sensing in this expression pattern, the expI/expR locus was cloned in Escherichia coli on the basis of its ability to direct production of acyl-homoserine lactone and then used to construct expI mutations in pelE::uidA, pelL::uidA, and hrpN::uidA Erwinia chrysanthemi strains. Mutation of expI had no apparent effect on the growth-phase-dependent expression of hrpN and pelE, or on the virulence of E. chrysanthemi in witloof chicory leaves. Overexpression of hrpN in E. chrysanthemi resulted in approximately 50% reduction of lesion size on chicory leaves without an

  10. Mutant heterosis in rice

    International Nuclear Information System (INIS)

    1987-01-01

    In the variety TKM6 a high yielding semidwarf mutant has been induced. This TKM6 mutant was used in test crosses with a number of other varieties and mutants to examine the extent of heterosis of dwarfs in rice and to select superior crosses. An excerpt of the published data is given. It appears from the backcross of the mutant with its original variety, that an increase in number of productive tillers occurs in the hybrid, leading to a striking grain yield increase, while the semi-dwarf culm length (the main mutant character) reverts to the normal phenotype. In the cross with IR8 on the other hand, there is only a minimal increase in tiller number but a substantial increase in TGW leading to more than 30% yield increase over the better parent

  11. Allele-Specific Chromatin Recruitment and Therapeutic Vulnerabilities of ESR1 Activating Mutations.

    Science.gov (United States)

    Jeselsohn, Rinath; Bergholz, Johann S; Pun, Matthew; Cornwell, MacIntosh; Liu, Weihan; Nardone, Agostina; Xiao, Tengfei; Li, Wei; Qiu, Xintao; Buchwalter, Gilles; Feiglin, Ariel; Abell-Hart, Kayley; Fei, Teng; Rao, Prakash; Long, Henry; Kwiatkowski, Nicholas; Zhang, Tinghu; Gray, Nathanael; Melchers, Diane; Houtman, Rene; Liu, X Shirley; Cohen, Ofir; Wagle, Nikhil; Winer, Eric P; Zhao, Jean; Brown, Myles

    2018-02-12

    Estrogen receptor α (ER) ligand-binding domain (LBD) mutations are found in a substantial number of endocrine treatment-resistant metastatic ER-positive (ER + ) breast cancers. We investigated the chromatin recruitment, transcriptional network, and genetic vulnerabilities in breast cancer models harboring the clinically relevant ER mutations. These mutants exhibit both ligand-independent functions that mimic estradiol-bound wild-type ER as well as allele-specific neomorphic properties that promote a pro-metastatic phenotype. Analysis of the genome-wide ER binding sites identified mutant ER unique recruitment mediating the allele-specific transcriptional program. Genetic screens identified genes that are essential for the ligand-independent growth driven by the mutants. These studies provide insights into the mechanism of endocrine therapy resistance engendered by ER mutations and potential therapeutic targets. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Alopecia in a viable phospholipase C delta 1 and phospholipase C delta 3 double mutant.

    Directory of Open Access Journals (Sweden)

    Fabian Runkel

    Full Text Available BACKGROUND: Inositol 1,4,5trisphosphate (IP(3 and diacylglycerol (DAG are important intracellular signalling molecules in various tissues. They are generated by the phospholipase C family of enzymes, of which phospholipase C delta (PLCD forms one class. Studies with functional inactivation of Plcd isozyme encoding genes in mice have revealed that loss of both Plcd1 and Plcd3 causes early embryonic death. Inactivation of Plcd1 alone causes loss of hair (alopecia, whereas inactivation of Plcd3 alone has no apparent phenotypic effect. To investigate a possible synergy of Plcd1 and Plcd3 in postnatal mice, novel mutations of these genes compatible with life after birth need to be found. METHODOLOGY/PRINCIPAL FINDINGS: We characterise a novel mouse mutant with a spontaneously arisen mutation in Plcd3 (Plcd3(mNab that resulted from the insertion of an intracisternal A particle (IAP into intron 2 of the Plcd3 gene. This mutation leads to the predominant expression of a truncated PLCD3 protein lacking the N-terminal PH domain. C3H mice that carry one or two mutant Plcd3(mNab alleles are phenotypically normal. However, the presence of one Plcd3(mNab allele exacerbates the alopecia caused by the loss of functional Plcd1 in Del(9olt1Pas mutant mice with respect to the number of hair follicles affected and the body region involved. Mice double homozygous for both the Del(9olt1Pas and the Plcd3(mNab mutations survive for several weeks and exhibit total alopecia associated with fragile hair shafts showing altered expression of some structural genes and shortened phases of proliferation in hair follicle matrix cells. CONCLUSIONS/SIGNIFICANCE: The Plcd3(mNab mutation is a novel hypomorphic mutation of Plcd3. Our investigations suggest that Plcd1 and Plcd3 have synergistic effects on the murine hair follicle in specific regions of the body surface.

  13. Precocious metamorphosis in the juvenile hormone-deficient mutant of the silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Takaaki Daimon

    Full Text Available Insect molting and metamorphosis are intricately governed by two hormones, ecdysteroids and juvenile hormones (JHs. JHs prevent precocious metamorphosis and allow the larva to undergo multiple rounds of molting until it attains the proper size for metamorphosis. In the silkworm, Bombyx mori, several "moltinism" mutations have been identified that exhibit variations in the number of larval molts; however, none of them have been characterized molecularly. Here we report the identification and characterization of the gene responsible for the dimolting (mod mutant that undergoes precocious metamorphosis with fewer larval-larval molts. We show that the mod mutation results in complete loss of JHs in the larval hemolymph and that the mutant phenotype can be rescued by topical application of a JH analog. We performed positional cloning of mod and found a null mutation in the cytochrome P450 gene CYP15C1 in the mod allele. We also demonstrated that CYP15C1 is specifically expressed in the corpus allatum, an endocrine organ that synthesizes and secretes JHs. Furthermore, a biochemical experiment showed that CYP15C1 epoxidizes farnesoic acid to JH acid in a highly stereospecific manner. Precocious metamorphosis of mod larvae was rescued when the wild-type allele of CYP15C1 was expressed in transgenic mod larvae using the GAL4/UAS system. Our data therefore reveal that CYP15C1 is the gene responsible for the mod mutation and is essential for JH biosynthesis. Remarkably, precocious larval-pupal transition in mod larvae does not occur in the first or second instar, suggesting that authentic epoxidized JHs are not essential in very young larvae of B. mori. Our identification of a JH-deficient mutant in this model insect will lead to a greater understanding of the molecular basis of the hormonal control of development and metamorphosis.

  14. Plasminogen alleles influence susceptibility to invasive aspergillosis.

    Directory of Open Access Journals (Sweden)

    Aimee K Zaas

    2008-06-01

    Full Text Available Invasive aspergillosis (IA is a common and life-threatening infection in immunocompromised individuals. A number of environmental and epidemiologic risk factors for developing IA have been identified. However, genetic factors that affect risk for developing IA have not been clearly identified. We report that host genetic differences influence outcome following establishment of pulmonary aspergillosis in an exogenously immune suppressed mouse model. Computational haplotype-based genetic analysis indicated that genetic variation within the biologically plausible positional candidate gene plasminogen (Plg; Gene ID 18855 correlated with murine outcome. There was a single nonsynonymous coding change (Gly110Ser where the minor allele was found in all of the susceptible strains, but not in the resistant strains. A nonsynonymous single nucleotide polymorphism (Asp472Asn was also identified in the human homolog (PLG; Gene ID 5340. An association study within a cohort of 236 allogeneic hematopoietic stem cell transplant (HSCT recipients revealed that alleles at this SNP significantly affected the risk of developing IA after HSCT. Furthermore, we demonstrated that plasminogen directly binds to Aspergillus fumigatus. We propose that genetic variation within the plasminogen pathway influences the pathogenesis of this invasive fungal infection.

  15. First TILLING platform in Cucurbita pepo: a new mutant resource for gene function and crop improvement.

    Science.gov (United States)

    Vicente-Dólera, Nelly; Troadec, Christelle; Moya, Manuel; del Río-Celestino, Mercedes; Pomares-Viciana, Teresa; Bendahmane, Abdelhafid; Picó, Belén; Román, Belén; Gómez, Pedro

    2014-01-01

    Although the availability of genetic and genomic resources for Cucurbita pepo has increased significantly, functional genomic resources are still limited for this crop. In this direction, we have developed a high throughput reverse genetic tool: the first TILLING (Targeting Induced Local Lesions IN Genomes) resource for this species. Additionally, we have used this resource to demonstrate that the previous EMS mutant population we developed has the highest mutation density compared with other cucurbits mutant populations. The overall mutation density in this first C. pepo TILLING platform was estimated to be 1/133 Kb by screening five additional genes. In total, 58 mutations confirmed by sequencing were identified in the five targeted genes, thirteen of which were predicted to have an impact on the function of the protein. The genotype/phenotype correlation was studied in a peroxidase gene, revealing that the phenotype of seedling homozygous for one of the isolated mutant alleles was albino. These results indicate that the TILLING approach in this species was successful at providing new mutations and can address the major challenge of linking sequence information to biological function and also the identification of novel variation for crop breeding.

  16. Analysis of Escherichia coli nicotinate mononucleotide adenylyltransferase mutants in vivo and in vitro

    Directory of Open Access Journals (Sweden)

    Rydén-Aulin Monica

    2005-09-01

    Full Text Available Abstract Background Adenylation of nicotinate mononucleotide to nicotinate adenine dinucleotide is the penultimate step in NAD+ synthesis. In Escherichia coli, the enzyme nicotinate mononucleotide adenylyltransferase is encoded by the nadD gene. We have earlier made an initial characterization in vivo of two mutant enzymes, NadD72 and NadD74. Strains with either mutation have decreased intracellular levels of NAD+, especially for one of the alleles, nadD72. Results In this study these two mutant proteins have been further characterized together with ten new mutant variants. Of the, in total, twelve mutations four are in a conserved motif in the C-terminus and eight are in the active site. We have tested the activity of the enzymes in vitro and their effect on the growth phenotype in vivo. There is a very good correlation between the two data sets. Conclusion The mutations in the C-terminus did not reveal any function for the conserved motif. On the other hand, our data has lead us to assign amino acid residues His-19, Arg-46 and Asp-109 to the active site. We have also shown that the nadD gene is essential for growth in E. coli.

  17. Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes

    NARCIS (Netherlands)

    Mehterov, Nikolay; Balazadeh, Salma; Hille, Jacques; Toneva, Valentina; Mueller-Roeber, Bernd; Gechev, Tsanko

    2012-01-01

    The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ which stimulate the intracellular formation of H2O2 or superoxide anions,

  18. An allele of the crm gene blocks cyanobacterial circadian rhythms.

    Science.gov (United States)

    Boyd, Joseph S; Bordowitz, Juliana R; Bree, Anna C; Golden, Susan S

    2013-08-20

    The SasA-RpaA two-component system constitutes a key output pathway of the cyanobacterial Kai circadian oscillator. To date, rhythm of phycobilisome associated (rpaA) is the only gene other than kaiA, kaiB, and kaiC, which encode the oscillator itself, whose mutation causes completely arrhythmic gene expression. Here we report a unique transposon insertion allele in a small ORF located immediately upstream of rpaA in Synechococcus elongatus PCC 7942 termed crm (for circadian rhythmicity modulator), which results in arrhythmic promoter activity but does not affect steady-state levels of RpaA. The crm ORF complements the defect when expressed in trans, but only if it can be translated, suggesting that crm encodes a small protein. The crm1 insertion allele phenotypes are distinct from those of an rpaA null; crm1 mutants are able to grow in a light:dark cycle and have no detectable oscillations of KaiC phosphorylation, whereas low-amplitude KaiC phosphorylation rhythms persist in the absence of RpaA. Levels of phosphorylated RpaA in vivo measured over time are significantly altered compared with WT in the crm1 mutant as well as in the absence of KaiC. Taken together, these results are consistent with the hypothesis that the Crm polypeptide modulates a circadian-specific activity of RpaA.

  19. Assessment of the myostatin Q204X allele using an allelic discrimination assay

    OpenAIRE

    Sifuentes-Rincón,Ana M.; Puentes-Montiel,Herlinda E.; Moreno-Medina,Víctor R.; Rosa-Reyna,Xóchitl F. de la

    2006-01-01

    An allelic discrimination assay was designed and used to determine the genotypic and allelic frequencies of the myostatin (MSTN) gene Q204X allele from two Mexican Full-French herds. The assay is a simple high throughput genotyping method that could be applied to investigate the effect of the Q204X allele on the Charolais breed.

  20. Genetic studies with morphological mutants of Aspergillus niger

    International Nuclear Information System (INIS)

    Roy, Ponty; Das, Arati

    1979-01-01

    Three classes of coloured mutations, viz., fawn, yellow and green, occurred recurrently among the population following UV- and γ-radiation from Co 60 of a wild Aspergillus niger strain 350. Ten mutants were picked up and complementation tests were performed by growing them in pairwise combinations. In two cases, allelic mutants of the same colour were observed. All these mutants were again grown in pairwise crosses with a brown A. niger mutant of different lineage. A poor heterokaryotic growth was, however, observed in one combination which later produced a diploid heterozygous nucleus. It segregated spontaneously to develop a large variety of colonies ranging from haploidy to diploidy including aneuploids. These have been analysed genetically and the possible explanations have been given. (auth.)

  1. Implication of HLA-DMA Alleles in Corsican IDDM

    Directory of Open Access Journals (Sweden)

    P. Cucchi-Mouillot

    1998-01-01

    Full Text Available The HLA-DM molecule catalyses the CLIP/antigen peptide exchange in the classical class II peptide-binding groove. As such, DM is an antigen presentation regulator and may be linked to autoimmune diseases. Using PCR derived methods, a relationship was revealed between DM gene polymorphism and IDDM, in a Corsican population. The DMA*0101 allele was observed to confer a significant predisposition to this autoimmune disease while the DMA*0102 allele protected significantly. Experiments examining polymorphism of the HLA-DRB1 gene established that these relationships are not a consequence of linkage disequilibrium with HLA-DRB1 alleles implicated in this pathology. The study of the DMA gene could therefore be an additional tool for early IDDM diagnosis in the Corsican population.

  2. Global regulatory roles of the cAMP/PKA pathway revealed by phenotypic, transcriptomic and phosphoproteomic analyses in a null mutant of the PKA catalytic subunit in Candida albicans.

    Science.gov (United States)

    Cao, Chengjun; Wu, Mei; Bing, Jian; Tao, Li; Ding, Xuefen; Liu, Xiaoyun; Huang, Guanghua

    2017-07-01

    The conserved cAMP-dependent protein kinase (PKA) plays critical roles in the regulation of morphological transitions and virulence in the human fungal pathogen Candida albicans. It has long been thought that the PKA catalytic subunit is essential for cell viability in this fungus. Paradoxically, the single adenylyl cyclase-encoding gene, CYR1, which is required for the production of cAMP in C. albicans, is not essential for cell growth. Here, a double mutant of TPK1 and TPK2 (tpk2/tpk2 tpk1/tpk1, t2t1), which encode two isoforms of the PKA catalytic subunit was successfully generated, suggesting that this subunit is not essential for cell viability. Inactivation of the PKA catalytic subunit blocked filamentation and dramatically attenuated white-to-opaque switching, but promoted sexual mating. Comparative transcriptomic analyses demonstrated that the t2t1 and cyr1/cyr1 mutants exhibited similar global gene expression profiles. Compared with the WT strain, the general transcriptional activity and metabolism were significantly decreased in both the t2t1 and cyr1/cyr1 mutants. Using combined phosphoproteomic and bioinformatic analyses, we identified 181 potential PKA phosphorylation targets, which represent 148 unique proteins involved in a wide spectrum of biological processes. The study sheds new insights into the global regulatory features of the cAMP/PKA pathway in C. albicans. © 2017 John Wiley & Sons Ltd.

  3. Hitchhiking and Selective Sweeps of Plasmodium falciparum Sulfadoxine and Pyrimethamine Resistance Alleles in a Population from Central Africa▿ †

    Science.gov (United States)

    McCollum, Andrea M.; Basco, Leonardo K.; Tahar, Rachida; Udhayakumar, Venkatachalam; Escalante, Ananias A.

    2008-01-01

    Sulfadoxine-pyrimethamine (SP) resistance in Plasmodium falciparum is encoded by a number of mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes. Here, we have characterized point mutations in dhfr and dhps and microsatellite loci around dhfr on chromosome 4 and dhps on chromosome 8 as well as neutral markers on chromosomes 2 and 3 in 332 samples from Yaoundé, Cameroon. The triple mutant dhfr haplotype that originated in Southeast Asia is the most predominant in this sample set, but we also find additional independent haplotypes at low frequency and an incipient process of genetic differentiation among alleles of Southeast Asian origin. As reported for other African populations, we find evidence of a selective sweep for resistant dhfr mutants in this Cameroonian population due to drug selection. Although we find evidence for a selective sweep in dhps mutants associated with SP resistance, the dynamics of dhps mutants appear different than those observed for dhfr mutants. Overall, our results yield support for the use of microsatellite markers to track resistant parasites; however, the detection of resistant dhfr alleles in low frequency, the evidence of divergence among dhfr alleles that share a common evolutionary origin, and the distinct dynamics of resistant dhps alleles emphasize the importance of comprehensive, population-based investigations to evaluate the effects of drug selection on parasite populations. PMID:18765692

  4. Population based allele frequencies of disease associated polymorphisms in the Personalized Medicine Research Project.

    Science.gov (United States)

    Cross, Deanna S; Ivacic, Lynn C; Stefanski, Elisha L; McCarty, Catherine A

    2010-06-17

    There is a lack of knowledge regarding the frequency of disease associated polymorphisms in populations and population attributable risk for many populations remains unknown. Factors that could affect the association of the allele with disease, either positively or negatively, such as race, ethnicity, and gender, may not be possible to determine without population based allele frequencies.Here we used a panel of 51 polymorphisms previously associated with at least one disease and determined the allele frequencies within the entire Personalized Medicine Research Project population based cohort. We compared these allele frequencies to those in dbSNP and other data sources stratified by race. Differences in allele frequencies between self reported race, region of origin, and sex were determined. There were 19544 individuals who self reported a single racial category, 19027 or (97.4%) self reported white Caucasian, and 11205 (57.3%) individuals were female. Of the 11,208 (57%) individuals with an identifiable region of origin 8337 or (74.4%) were German.41 polymorphisms were significantly different between self reported race at the 0.05 level. Stratification of our Caucasian population by self reported region of origin revealed 19 polymorphisms that were significantly different (p = 0.05) between individuals of different origins. Further stratification of the population by gender revealed few significant differences in allele frequencies between the genders. This represents one of the largest population based allele frequency studies to date. Stratification by self reported race and region of origin revealed wide differences in allele frequencies not only by race but also by region of origin within a single racial group. We report allele frequencies for our Asian/Hmong and American Indian populations; these two minority groups are not typically selected for population allele frequency detection. Population wide allele frequencies are important for the design and

  5. Response of the pearly eye melon fly Bactrocera cucurbitae (Coquillett)(Diptera:Tephritidae) mutant to host-associated visual cues

    Science.gov (United States)

    We report on a pearly eye mutant (PEM) line generated from a single male Bactrocera cucurbitae collected in Kapoho, Hawaii. Crossing experiments with colony wild-type flies indicate that the locus controlling this trait is autosomal and the mutant allele is recessive. Experiments with females to ass...

  6. Virulence attributes and hyphal growth of C. neoformans are quantitative traits and the MATalpha allele enhances filamentation.

    Directory of Open Access Journals (Sweden)

    Xiaorong Lin

    2006-11-01

    Full Text Available Cryptococcus neoformans is a fungal human pathogen with a bipolar mating system. It undergoes a dimorphic transition from a unicellular yeast to hyphal filamentous growth during mating and monokaryotic fruiting. The traditional sexual cycle that leads to the production of infectious basidiospores involves cells of both alpha and a mating type. Monokaryotic fruiting is a modified form of sexual reproduction that involves cells of the same mating type, most commonly alpha, which is the predominant mating type in both the environment and clinical isolates. However, some a isolates can also undergo monokaryotic fruiting. To determine whether mating type and other genetic loci contribute to the differences in fruiting observed between alpha and a cells, we applied quantitative trait loci (QTL mapping to an inbred population of F2 progeny. We discovered that variation in hyphal length produced during fruiting is a quantitative trait resulting from the combined effects of multiple genetic loci, including the mating type (MAT locus. Importantly, the alpha allele of the MAT locus enhanced hyphal growth compared with the a allele. Other virulence traits, including melanization and growth at 39 degrees C, also are quantitative traits that share a common QTL with hyphal growth. The Mac1 transcription factor, encoded in this common QTL, regulates copper homeostasis. MAC1 allelic differences contribute to phenotypic variation, and mac1Delta mutants exhibit defects in filamentation, melanin production, and high temperature growth. Further characterization of these QTL regions will reveal additional quantitative trait genes controlling biological processes central to fungal development and pathogenicity.

  7. Breeding cultivars of barley and mustard containing biochemical mutants

    Energy Technology Data Exchange (ETDEWEB)

    Oram, R N [Division of Plant industry, CSIRO, Canberra (Australia)

    1990-01-01

    Full text: The inactivation of dominant and co-dominant alleles is becoming increasingly important in changing the composition of seed carbohydrates, protein, oil, fibre and secondary products to suit modern food and feed technologies. In barley, breeding lines adapted to south-eastern Australian conditions have been developed containing a waxy endosperm from the Japanese variety 'Sumire Mochi', the high lysine gene lys from cv. 'Hiproly' of Ethiopia, and the induced high lysine mutant gene lys 3a from 'Risoe 1508'. The improved mutant lines yield 12-34% less than the highest yielding feed barley. The lys and lys 3a alleles suppress the formation of prolamins, the waxy allele inhibits the formation of amylose. It seems difficult to modify the background genotype to fully compensate for the reduction of major storage carbohydrate or protein compounds. However, waxy barleys have uses in some human foods and a premium can be paid to producers. The grain of the provisionally-patented waxy cultivar Wasiro is suitable for pearling. It contains 5% {beta}-glucan (soluble fibre) and therefore should be as effective as oat bran for reducing blood cholesterol. In Indian mustard (Brassica juncea), three cultivars differing in date of maturity, each containing the spontaneous mutant alleles for low erucic acid levels in the seed oil, have been developed to produce a high quality, mildly flavoured cooking/salad oil. The concentration of glucosinolates in the seed meal must be reduced to make it palatable and non-toxic to pigs and poultry. Three B. juncea lines were treated in up to four successive generations with gamma rays or EMS. 60,000 seed samples were analysed in subsequent generations. Two induced mutants with reduced glucosinolate concentrations are now available besides 4 naturally-occurring sources with only little reduced yields. Recombination may give a high-yielding low erucic acid and low glucosinolate variety of B. juncea. (author)

  8. Breeding cultivars of barley and mustard containing biochemical mutants

    International Nuclear Information System (INIS)

    Oram, R.N.

    1990-01-01

    Full text: The inactivation of dominant and co-dominant alleles is becoming increasingly important in changing the composition of seed carbohydrates, protein, oil, fibre and secondary products to suit modern food and feed technologies. In barley, breeding lines adapted to south-eastern Australian conditions have been developed containing a waxy endosperm from the Japanese variety 'Sumire Mochi', the high lysine gene lys from cv. 'Hiproly' of Ethiopia, and the induced high lysine mutant gene lys 3a from 'Risoe 1508'. The improved mutant lines yield 12-34% less than the highest yielding feed barley. The lys and lys 3a alleles suppress the formation of prolamins, the waxy allele inhibits the formation of amylose. It seems difficult to modify the background genotype to fully compensate for the reduction of major storage carbohydrate or protein compounds. However, waxy barleys have uses in some human foods and a premium can be paid to producers. The grain of the provisionally-patented waxy cultivar Wasiro is suitable for pearling. It contains 5% β-glucan (soluble fibre) and therefore should be as effective as oat bran for reducing blood cholesterol. In Indian mustard (Brassica juncea), three cultivars differing in date of maturity, each containing the spontaneous mutant alleles for low erucic acid levels in the seed oil, have been developed to produce a high quality, mildly flavoured cooking/salad oil. The concentration of glucosinolates in the seed meal must be reduced to make it palatable and non-toxic to pigs and poultry. Three B. juncea lines were treated in up to four successive generations with gamma rays or EMS. 60,000 seed samples were analysed in subsequent generations. Two induced mutants with reduced glucosinolate concentrations are now available besides 4 naturally-occurring sources with only little reduced yields. Recombination may give a high-yielding low erucic acid and low glucosinolate variety of B. juncea. (author)

  9. Molecular characterization of thymidine kinase mutants of human cells induced by densely ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, A; Little, J B

    1989-04-01

    In order to characterize the nature of mutants induced by densely ionizing radiations at an autosomal locus, the authors have isolated a series of 99 thymidine kinase (tk) mutants of human TK6 lymphoblastoid cells iraadiated with either fast neutrons or accelerated argon ions. Individual muant clones were examined for alterations in their restriction fragment pattern after hybridization with a human cDNA probe for tk. A restriction fragment length polymorphism (RFLP) allowed identification of the active tk allele. Among the neutron-induced mutants, 34/52 exhibited loss of the previously active allele while 6/52 exhibited intragenic rearrangements. Among the argon-induced mutants 27/46 exhibited allele loses and 10/46 showed rearrangements within the tk locus. The remaining mutants had restriction patterns indistinguishable from the TK6 parent. Each of the mutant clones was further examined for structural alterations within the c-erbAl locus which has been localized to chromosome 17q11-q22, at some unknown distance from the human tk locus at chromosome 17q21-q22. A substantial proportion (54%) of tk mutants induced by densely ionizing radiation showed loss of the c-erb locus on the homologous chromosome, suggesting that the mutations involve large-scale genetic changes. (author). 51 refs.; 2 figs.; 6 tabs.

  10. Genetic and agronomic evaluation of induced semi-dwarf mutants of rice

    International Nuclear Information System (INIS)

    Rutger, J.N.

    1984-01-01

    Induced semi-dwarf mutants have played an important role in California's rapid shift from nearly all tall rice varieties in 1978 to nearly all semi-dwarf varieties at present. In 1981 over half of the California rice area was planted with semi-dwarf varieties carrying the induced mutant semi-dwarfing gene sd 1 , while much of the other half was planted to a variety deriving its semi-dwarfism from IR8. The sd 1 mutant is allelic to the major semi-dwarfing gene in DGWG and IR8. Current objectives are to determine the inheritance of new semi-dwarf mutants, including allelism tests with sd 1 , and to evaluate the agronomic potential of nonallelic sources and of double-dwarfs. To date semi-dwarf mutants from 10 varieties have been partially or completely evaluated. At least three nonallelic semi-dwarfing genes, sd 1 , sd 2 , and sd 4 , have been described. Rather than attempt to determine all possible allelic relationships of new mutants, crosses are being made only to the reference sd 1 source, since sd 1 , still seems to be the most productive semi-dwarfing gene source. However, nonallelic semi-dwarf mutants in the varieties M5 and Labelle may be useful if genetic vulnerability from widespread usage of the sd 1 source becomes a problem. (author)

  11. Comparative population analysis of metallothionein promoter alleles suggests stress-induced microevolution in the field.

    NARCIS (Netherlands)

    Janssens, T.K.S.; Del Rio Lopez, R.; Mariën, A.G.H.; Timmermans, M.J.T.N.; Montagne-Wajer, K; van Straalen, N.M.; Roelofs, D.

    2008-01-01

    We investigate a model system for microevolution of transcriptional regulation: metallothionein expression in springtails. A previous survey of the metallothionein promoter in Orchesella cincta (Collembola) revealed nine alleles with differential basal activities and responses to cadmium and

  12. Comparative population analysis of metallothionein promoter alleles suggests stress-induced microevolution in the field

    NARCIS (Netherlands)

    Janssens, Thierry K S; Lopéz, Ricardo del Rio; Mariën, Janine; Timmermans, Martijn J T N; Montagne-Wajer, K; van Straalen, Nico M; Roelofs, Dick

    2008-01-01

    We investigate a model system for microevolution of transcriptional regulation: metallothionein expression in springtails. A previous survey of the metallothionein promoter in Orchesella cincta (Collembola) revealed nine alleles with differential basal activities and responses to cadmium and

  13. Productive mutants of niger

    International Nuclear Information System (INIS)

    Misra, R.C.

    2001-01-01

    Seeds of six niger (Guizotia abyssinica Cass.) varieties ('GA-10', 'ONS-8', 'IGP-72', 'N-71', 'NB-9' and 'UN-4') were treated with 0.5, 0.75 and 1% ethyl methanesulphonate. After four generations of selection, 29 mutant lines were developed and those were evaluated from 1990-92 during Kharif (July to October) and Rabi (December to March) seasons. Average plant characteristics and yield data of four high yielding mutants along with 'IGP-76' (National Check), GA-10 (Zonal Check) and 'Semiliguda Local' (Local Check) are presented

  14. Genetic and Biochemical Analysis of Intragenic Complementation Events among Nitrate Reductase Apoenzyme-Deficient Mutants of Nicotiana Plumbaginifolia

    OpenAIRE

    Pelsy, F.; Gonneau, M.

    1991-01-01

    Intragenic complementation has been observed between apoenzyme nitrate reductase-deficient mutants (nia) of Nicotiana plumbaginifolia. In vivo as in vitro, the NADH-nitrate reductase (NR) activity in plants heterozygous for two different nia alleles was lower than in the wild type plant, but the plants were able to grow on nitrate as a sole nitrogen source. NR activity, absent in extracts of homozygous nia mutants was restored by mixing extracts from two complementing nia mutants. These obser...

  15. Isolation and characterization of X-linked mutants of Drosophila melanogaster which are sensitive to mutagens

    International Nuclear Information System (INIS)

    Boyd, J.B.; Golino, M.D.; Nguyen, T.D.; Green, M.M.

    1976-01-01

    Thirteen X-linked mutants have been isolated in Drosophila melanogaster which render male and homozygous female larvae sensitive to the mutagen methyl methanesulfonate. Their characterization and preliminary assignment to functional groups is described. Four of these mutants are alleles of mei-41. Like previously isolated alleles of this locus, these mutants reduce fertility and increase loss and nondisjunction of the X-chromosome in homozygous females. The remaining mutants have been tentatively assigned to six functional groups (two mutants to the mus(1)101 locus, two to mus(1)102, two to mus(1)103, and one each to mus(1)104, mus(1)105, and mus(1)106. Several of the complementation groups can be distinguished on the basis of nondisjunction and cross sensitivity to mutagens. Females homozygous for the mei-41, mus(1)101 and mus(1)102 mutants exhibit elevated levels of nondisjunction. Mutants belonging to complementation groups mei-41, mus(1)101, and mus(1)104 are sensitive to nitrogen mustard (HN2) in addition to their MMS sensitivity. Among these mutants there is currently a direct correlation between sensitivity to HN2, sensitivity to 2-acetylaminofluorene and a deficiency in post-replication repair. Only the mei-41 mutants are hypersensitive to uv radiation, although several of the mutants exhibit sensitivity to γ-rays. Semidominance is observed in female larvae of the mei-41, mus(1)104, and mus(1)103 mutants after exposure to high concentrations of MMS. The properties of the mutants generally conform to a pattern which has been established for related mutants in yeast

  16. Allelic variation of bile salt hydrolase genes in Lactobacillus salivarius does not determine bile resistance levels.

    LENUS (Irish Health Repository)

    Fang, Fang

    2009-09-01

    Commensal lactobacilli frequently produce bile salt hydrolase (Bsh) enzymes whose roles in intestinal survival are unclear. Twenty-six Lactobacillus salivarius strains from different sources all harbored a bsh1 allele on their respective megaplasmids. This allele was related to the plasmid-borne bsh1 gene of the probiotic strain UCC118. A second locus (bsh2) was found in the chromosomes of two strains that had higher bile resistance levels. Four Bsh1-encoding allele groups were identified, defined by truncations or deletions involving a conserved residue. In vitro analyses showed that this allelic variation was correlated with widely varying bile deconjugation phenotypes. Despite very low activity of the UCC118 Bsh1 enzyme, a mutant lacking this protein had significantly lower bile resistance, both in vitro and during intestinal transit in mice. However, the overall bile resistance phenotype of this and other strains was independent of the bsh1 allele type. Analysis of the L. salivarius transcriptome upon exposure to bile and cholate identified a multiplicity of stress response proteins and putative efflux proteins that appear to broadly compensate for, or mask, the effects of allelic variation of bsh genes. Bsh enzymes with different bile-degrading kinetics, though apparently not the primary determinants of bile resistance in L. salivarius, may have additional biological importance because of varying effects upon bile as a signaling molecule in the host.

  17. Transposon mutagenesis reveals differential pathogenesis of Ralstonia solanacearum on tomato and Arabidopsis.

    Science.gov (United States)

    Lin, Yu-Mei; Chou, I-Chun; Wang, Jaw-Fen; Ho, Fang-I; Chu, Yu-Ju; Huang, Pei-Cheng; Lu, Der-Kang; Shen, Hwei-Ling; Elbaz, Mounira; Huang, Shu-Mei; Cheng, Chiu-Ping

    2008-09-01

    Ralstonia solanacearum causes a deadly wilting disease on a wide range of crops. To elucidate pathogenesis of this bacterium in different host plants, we set out to identify R. solanacearum genes involved in pathogenesis by screening random transposon insertion mutants of a highly virulent strain, Pss190, on tomato and Arabidopsis thaliana. Mutants exhibiting various decreased virulence levels on these two hosts were identified. Sequence analysis showed that most, but not all, of the identified pathogenesis genes are conserved among distinct R. solanacearum strains. A few of the disrupted loci were not reported previously as being involved in R. solanacearum pathogenesis. Notably, a group of mutants exhibited differential pathogenesis on tomato and Arabidopsis. These results were confirmed by characterizing allelic mutants in one other R. solanacearum strain of the same phylotype. The significantly decreased mutants' colonization in Arabidopsis was found to be correlated with differential pathogenesis on these two plants. Differential requirement of virulence genes suggests adaptation of this bacterium in different host environments. Together, this study reveals commonalities and differences of R. solanacearum pathogenesis on single solanaceous and nonsolanaceous hosts, and provides important new insights into interactions between R. solanacearum and different host plants.

  18. Dominant hemimelia and En-1 on mouse chromosome 1 are not allelic.

    Science.gov (United States)

    Higgins, M; Hill, R E; West, J D

    1992-08-01

    Previous studies have shown that En-1, a homeobox-containing gene, maps close to or at the Dh locus in the mouse. Since homeobox-containing genes are key genes in the control of development the close proximity of En-1 to the developmentally significant gene Dh raised the possibility that the Dh mutation represented a mutant allele of En-1. A genetic analysis involving En-1, Dh, and other chromosome 1 markers (Emv-17, ln and Pep-3) shows that although Dh and En-1 are closely linked they are separable by recombination (4/563). The likely gene order and recombination frequencies of these loci are: ln (5.2 +/- 0.9) Emv-17 (1.1 +/- 0.4) Dh (0.7 +/- 0.4) En-1 (3.0 +/- 0.7) Pep-3. This shows that Dh is not a mutant allele of En-1.

  19. [Phenotypic effects of puroindoline gene alleles of bread wheat].

    Science.gov (United States)

    Chebotar, S V; Kurakina, K O; Khokhlov, O M; Chebotar, H O; Syvolap, Iu M

    2012-01-01

    85 winter bread wheat varieties and lines that have been developed mostly in Ukraine were analyzed with NIR for parameters of hardness and protein content. The hardness data were compared with the data of puroindoline gene alleles analysis done earlier and the published data. Significant variation of parameters of hardness was revealed when there was low polymorphism of puroindoline genes indicating the presence of additional genes that influence the hardness parameters.

  20. Detection of MPLW515L/K mutations and determination of allele frequencies with a single-tube PCR assay.

    Science.gov (United States)

    Takei, Hiraku; Morishita, Soji; Araki, Marito; Edahiro, Yoko; Sunami, Yoshitaka; Hironaka, Yumi; Noda, Naohiro; Sekiguchi, Yuji; Tsuneda, Satoshi; Ohsaka, Akimichi; Komatsu, Norio

    2014-01-01

    A gain-of-function mutation in the myeloproliferative leukemia virus (MPL) gene, which encodes the thrombopoietin receptor, has been identified in patients with essential thrombocythemia and primary myelofibrosis, subgroups of classic myeloproliferative neoplasms (MPNs). The presence of MPL gene mutations is a critical diagnostic criterion for these diseases. Here, we developed a rapid, simple, and cost-effective method of detecting two major MPL mutations, MPLW515L/K, in a single PCR assay; we termed this method DARMS (dual amplification refractory mutation system)-PCR. DARMS-PCR is designed to produce three different PCR products corresponding to MPLW515L, MPLW515K, and all MPL alleles. The amplicons are later detected and quantified using a capillary sequencer to determine the relative frequencies of the mutant and wild-type alleles. Applying DARMS-PCR to human specimens, we successfully identified MPL mutations in MPN patients, with the exception of patients bearing mutant allele frequencies below the detection limit (5%) of this method. The MPL mutant allele frequencies determined using DARMS-PCR correlated strongly with the values determined using deep sequencing. Thus, we demonstrated the potential of DARMS-PCR to detect MPL mutations and determine the allele frequencies in a timely and cost-effective manner.

  1. Detection of MPLW515L/K mutations and determination of allele frequencies with a single-tube PCR assay.

    Directory of Open Access Journals (Sweden)

    Hiraku Takei

    Full Text Available A gain-of-function mutation in the myeloproliferative leukemia virus (MPL gene, which encodes the thrombopoietin receptor, has been identified in patients with essential thrombocythemia and primary myelofibrosis, subgroups of classic myeloproliferative neoplasms (MPNs. The presence of MPL gene mutations is a critical diagnostic criterion for these diseases. Here, we developed a rapid, simple, and cost-effective method of detecting two major MPL mutations, MPLW515L/K, in a single PCR assay; we termed this method DARMS (dual amplification refractory mutation system-PCR. DARMS-PCR is designed to produce three different PCR products corresponding to MPLW515L, MPLW515K, and all MPL alleles. The amplicons are later detected and quantified using a capillary sequencer to determine the relative frequencies of the mutant and wild-type alleles. Applying DARMS-PCR to human specimens, we successfully identified MPL mutations in MPN patients, with the exception of patients bearing mutant allele frequencies below the detection limit (5% of this method. The MPL mutant allele frequencies determined using DARMS-PCR correlated strongly with the values determined using deep sequencing. Thus, we demonstrated the potential of DARMS-PCR to detect MPL mutations and determine the allele frequencies in a timely and cost-effective manner.

  2. Candidate Cancer Allele cDNA Collection | Office of Cancer Genomics

    Science.gov (United States)

    CTD2 researchers at the Broad Institute/DFCI have developed a collection of plasmids including mutant alleles found in sequencing studies of cancer. It includes somatic variants found in lung adenocarcinoma and across other cancer types. The clones enable researchers to characterize the function of the cancer variants in a high throughput experiments. These plasmids are collectively called the “Broad Target Accelerator Plasmid Collections”.

  3. Nonsense mutants in the bacteriophage T4D v gene

    Energy Technology Data Exchange (ETDEWEB)

    Minderhout, L van; Grimbergen, J; Groot, B de [Rijksuniversiteit Leiden (Netherlands). Lab. voor Stralengenetica en Chemische Mutagenese; Cohen (J.A.) Instituut voor Radiopathologie en Stralenbescherming, Leiden (Netherlands))

    1975-09-01

    Ten UV-sensitive mutants of T4D with the v phenotype were isolated. Of these ten mutants, two are amber and two opal. In UV curves and in photoreactivation and multiplicity reactivation experiments the nonsense mutants show the v phenotype in su/sup -/ hosts and almost the T4/sup +/ phenotype in su/sup +/ hosts. The mutations are located between rl and e and are alleles of v/sub 1/. In crosses with irradiated and non-irradiated phages the recombinant frequency is not reduced by uvs5. Amber uvs5 propagated in CR63 su/sup +/ is with B su/sup -/ just as sensitive to UV as uvs5 propagated in B su/sup -/, which permits the conclusion that the capsid of T4 phage particles does not contain the v gene product.

  4. Characterization of Novel Sorghum brown midrib Mutants from an EMS-Mutagenized Population

    OpenAIRE

    Sattler, Scott E.; Saballos, Ana; Xin, Zhanguo; Funnell-Harris, Deanna L.; Vermerris, Wilfred; Pedersen, Jeffrey F.

    2014-01-01

    Reducing lignin concentration in lignocellulosic biomass can increase forage digestibility for ruminant livestock and saccharification yields of biomass for bioenergy. In sorghum (Sorghum bicolor (L.) Moench) and several other C4 grasses, brown midrib (bmr) mutants have been shown to reduce lignin concentration. Putative bmr mutants isolated from an EMS-mutagenized population were characterized and classified based on their leaf midrib phenotype and allelism tests with the previously describe...

  5. Cloning of an E. coli RecA and yeast RAD51 homolog, radA, an allele of the uvsC in Aspergillus nidulans and its mutator effects.

    Science.gov (United States)

    Seong, K Y; Chae, S K; Kang, H S

    1997-04-30

    An E. coli RecA and yeast RAD51 homolog from Aspergillus nidulans, radA, has been cloned by screening genomic and cDNA libraries with a PCR-amplified probe. This probe was generated using primers carrying the conserved sequences of eukaryotic RecA homologs. The deduced amino acid sequence revealed two conserved Walker-A and -B type nucleotide-binding domains and exhibited 88%, 60%, and 53% identity with Mei-3 of Neurospora crassa, rhp51+ of Schizosaccharomyces pombe, and Rad51 of Saccharomyces cerevisiae, respectively. radA null mutants constructed by replacing the whole coding region with a selection marker showed high methyl methanesulfonate (MMS) sensitivity. Heterozygous diploids of radA disruptant with the uvsC114 mutant failed to complement with respect to MMS-sensitivity, indicating that radA is an allele of uvsC. In selecting spontaneous forward selenate resistant mutations, mutator effects were observed in radA null mutants similarly to those shown in uvsC114 mutant strains.

  6. Development of high yielding mutants in lentil

    International Nuclear Information System (INIS)

    Rajput, M.A.; Sarwar, G.; Siddiqui, K.A.

    2001-01-01

    Full text: Lentil (Lens culinaris Medik.) locally known as Masoor, is the second most important rabi pulse crop, after chickpea, in Pakistan. It is cultivated on an area of over 63,400 ha, which constitutes about 4.83% of the total area under pulses. The annual production of the crop is 28,200 tones with an average yield of 445 kg/ha. Yield at the national level is very low, about one-half of the world's yield, which is mainly due to non-availability of high yield potential genotypes. Keeping in view the importance of mutants in developing a large number of new varieties, an induced mutations programme was initiated at AEARC, Tandojam during 1987-88, to develop high yielding varieties in lentil. For this, seeds of two lentil varieties, 'Masoor-85' and 'ICARDA-8' had been irradiated with gamma-rays ranging from 100-600 Gy in NIAB, Faisalabad during 1990. Selections were made in M2 on the basis of earliness, plant height, branches/plant and 100 grain weight. After confirming these mutants in M3 they were promoted in station yield trials and studied continuously for three consecutive years (1993- 1995). Overall results revealed that these mutants have consistent improvement of earliness in flowering and maturity. Plant height also increased in all mutant lines except AEL 23/40/91 where reduction in this attribute was observed as compared to parent variety. Mutant lines AEL 49/20/91 and AEL 13/30/91 showed improvement in 100 grain weight. The improvement of some agronomic characters enhanced the yield of mutant lines in comparison to parent varieties (Masoor-85 and ICARDA-8). The diversity in yield over the respective parents was computed from 6.94 to 60.12%. From these encouraging results it is hoped that mutant lines like AEL 12/30/91 and AEL 49/20/91 may serve as potential lentil genotypes in future. (author)

  7. Improvements to a Markerless Allelic Exchange System for Bacillus anthracis.

    Directory of Open Access Journals (Sweden)

    Roger D Plaut

    Full Text Available A system was previously developed for conducting I-SceI-mediated allelic exchange in Bacillus anthracis. In this system, recombinational loss of a chromosomally-integrated allelic exchange vector is stimulated by creation of a double-stranded break within the vector by the homing endonuclease I-SceI. Although this system is reasonably efficient and represents an improvement in the tools available for allelic exchange in B. anthracis, researchers are nonetheless required to "pick and patch" colonies in order to identify candidate "exchangeants." In the present study, a number of improvements have been made to this system: 1 an improved I-SceI-producing plasmid includes oriT so that both plasmids can now be introduced by conjugation, thus avoiding the need for preparing electro-competent cells of each integration intermediate; 2 antibiotic markers have been changed to allow the use of the system in select agent strains; and 3 both plasmids have been marked with fluorescent proteins, allowing the visualization of plasmid segregation on a plate and obviating the need for "picking and patching." These modifications have made the process easier, faster, and more efficient, allowing for parallel construction of larger numbers of mutant strains. Using this improved system, the genes encoding the tripartite anthrax toxin were deleted singly and in combination from plasmid pXO1 of Sterne strain 34F2. In the course of this study, we determined that DNA transfer to B. anthracis could be accomplished by conjugation directly from a methylation-competent E. coli strain.

  8. Connexin mutants and cataracts

    Directory of Open Access Journals (Sweden)

    Eric C Beyer

    2013-04-01

    Full Text Available The lens is a multicellular, but avascular tissue that must stay transparent to allow normal transmission of light and focusing of it on the retina. Damage to lens cells and/or proteins can cause cataracts, opacities that disrupt these processes. The normal survival of the lens is facilitated by an extensive network of gap junctions formed predominantly of connexin46 and connexin50. Mutations of the genes that encode these connexins (GJA3 and GJA8 have been identified and linked to inheritance of cataracts in human families and mouse lines. In vitro expression studies of several of these mutants have shown that they exhibit abnormalities that may lead to disease. Many of the mutants reduce or modify intercellular communication due to channel alterations (including loss of function or altered gating or due to impaired cellular trafficking which reduces the number of gap junction channels within the plasma membrane. However, the abnormalities detected in studies of other mutants suggest that they cause cataracts through other mechanisms including gain of hemichannel function (leading to cell injury and death and formation of cytoplasmic accumulations (that may act as light scattering particles. These observations and the anticipated results of ongoing studies should elucidate the mechanisms of cataract development due to mutations of lens connexins and abnormalities of other lens proteins. They may also contribute to our understanding of the mechanisms of disease due to connexin mutations in other tissues.

  9. Effects of mutant human Ki-rasG12C gene dosage on murine lung tumorigenesis and signaling to its downstream effectors

    International Nuclear Information System (INIS)

    Dance-Barnes, Stephanie T.; Kock, Nancy D.; Floyd, Heather S.; Moore, Joseph E.; Mosley, Libyadda J.; D'Agostino, Ralph B.; Pettenati, Mark J.; Miller, Mark Steven

    2008-01-01

    Studies in cell culture have suggested that the level of RAS expression can influence the transformation of cells and the signaling pathways stimulated by mutant RAS expression. However, the levels of RAS expression in vivo appear to be subject to feedback regulation, limiting the total amount of RAS protein that can be expressed. We utilized a bitransgenic mouse lung tumor model that expressed the human Ki-ras G12C allele in a tetracycline-inducible, lung-specific manner. Treatment for 12 months with 500 μg/ml of doxycycline (DOX) allowed for maximal expression of the human Ki-ras G12C allele in the lung, and resulted in the development of focal hyperplasia and adenomas. We determined if different levels of mutant RAS expression would influence the phenotype of the lung lesions. Treatment with 25, 100 and 500 μg/ml of DOX resulted in dose-dependent increases in transgene expression and tumor multiplicity. Microscopic analysis of the lungs of mice treated with the 25 μg/ml dose of DOX revealed infrequent foci of hyperplasia, whereas mice treated with the 100 and 500 μg/ml doses exhibited numerous hyperplastic foci and also adenomas. Immunohistochemical and RNA analysis of the downstream effector pathways demonstrated that different levels of mutant RAS transgene expression resulted in differences in the expression and/or phosphorylation of specific signaling molecules. Our results suggest that the molecular alterations driving tumorigenesis may differ at different levels of mutant Ki-ras G12C expression, and this should be taken into consideration when inducible transgene systems are utilized to promote tumorigenesis in mouse models

  10. Leukemogenic Ptpn11 allele causes defective erythropoiesis in mice.

    Directory of Open Access Journals (Sweden)

    Tatiana Usenko

    Full Text Available Src homology 2 (SH2 domain-containing phosphatase 2 (SHP2, encoded by PTPN11, regulates signaling networks and cell fate in many tissues. Expression of oncogenic PTPN11 in the hematopoietic compartment causes myeloproliferative neoplasm (MPN in humans and mice. However, the stage-specific effect(s of mutant Ptpn11 on erythroid development have remained unknown. We found that expression of an activated, leukemogenic Ptpn11 allele, Ptpn11D61Y, specifically in the erythroid lineage causes dyserythropoiesis in mice. Ptpn11D61Y progenitors produce excess cKIT+ CD71+ Ter119- cells and aberrant numbers of cKITl° CD71+ erythroblasts. Mutant erythroblasts show elevated activation of ERK, AKT and STAT3 in response to EPO stimulation, and MEK inhibitor treatment blocks Ptpn11D61Y-evoked erythroid hyperproliferation in vitro. Thus, the expression of oncogenic Ptpn11 causes dyserythropoiesis in a cell-autonomous manner in vivo.

  11. Semi-dwarf mutants in triticale and wheat breeding

    International Nuclear Information System (INIS)

    Driscoll, C.J.

    1984-01-01

    The triticale lines Beagle and DR-IRA have been subjected to ionizing irradiation and chemical mutagenesis in order to produce semi-dwarf mutants. Beagle is 100 cm tall and DR-IRA 80 cm under average field conditions. A bulk then pedigree method is currently represented by 158 single plots of M 6 (or in some cases M 7 ) mutants that are from 5 to 35 cm shorter than the control variety. The shortest mutants are 65 cm in height. Forty of these mutants are also earlier flowering than the control varieties. Replicated yield testing will be conducted on confirmed mutants in 1983. Response to gibberellic acid of these mutants will also be determined. The Cornerstone male-sterility mutant (ms1c) on chromosome arm 4Aα has been combined with the GA-insensitive/reduced height gene Gai/Rht1 which is also on chromosome arm 4Aα. The ms1c mutant has also been combined with Gai/Rht2 on chromosome 4D and with both Gai/Rht1 and Gai/Rht2. The combination ms1c and Gai/Rht1 has been chosen as the basis of a composite cross. Thirteen varieties were tested with GA 3 and seven (Warigal, Aroona, Oxley, Banks, Avocet, Matipo and Toquifen) which contain Gai/Rht1 were crossed with ms1c Gai/Rht1 and entered into an interpollinating F 2 . The entire composite is homozygous for this semi-dwarf allele and selection will be practiced for increased height on a GA-insensitive background. (author)

  12. Functional PAK-2 knockout and replacement with a caspase cleavage-deficient mutant in mice reveals differential requirements of full-length PAK-2 and caspase-activated PAK-2p34.

    Science.gov (United States)

    Marlin, Jerry W; Chang, Yu-Wen E; Ober, Margaret; Handy, Amy; Xu, Wenhao; Jakobi, Rolf

    2011-06-01

    p21-Activated protein kinase 2 (PAK-2) has both anti- and pro-apoptotic functions depending on its mechanism of activation. Activation of full-length PAK-2 by the monomeric GTPases Cdc42 or Rac stimulates cell survival, whereas caspase activation of PAK-2 to the PAK-2p34 fragment is involved in the apoptotic response. In this study we use functional knockout of PAK-2 and gene replacement with the caspase cleavage-deficient PAK-2D212N mutant to differentiate the biological functions of full-length PAK-2 and caspase-activated PAK-2p34. Knockout of PAK-2 results in embryonic lethality at early stages before organ development, whereas replacement with the caspase cleavage-deficient PAK-2D212N results in viable and healthy mice, indicating that early embryonic lethality is caused by deficiency of full-length PAK-2 rather than lack of caspase activation to the PAK-2p34 fragment. However, deficiency of caspase activation of PAK-2 decreased spontaneous cell death of primary mouse embryonic fibroblasts and increased cell growth at high cell density. In contrast, stress-induced cell death by treatment with the anti-cancer drug cisplatin was not reduced by deficiency of caspase activation of PAK-2, but switched from an apoptotic to a nonapoptotic, caspase-independent mechanism. Homozygous PAK-2D212N primary mouse embryonic fibroblasts that lack the ability to generate the proapoptotic PAK-2p34 show less activation of the effector caspase 3, 6, and 7, indicating that caspase activation of PAK-2 amplifies the apoptotic response through a positive feedback loop resulting in more activation of effector caspases.

  13. Proteomic analysis reveals differential accumulation of small heat shock proteins and late embryogenesis abundant proteins between ABA-deficient mutant vp5 seeds and wild-type Vp5 seeds in maize

    Directory of Open Access Journals (Sweden)

    Xiaolin eWu

    2015-01-01

    Full Text Available ABA is a major plant hormone that plays important roles during many phases of plant life cycle, including seed development, maturity and dormancy, and especially the acquisition of desiccation tolerance. Understanding of the molecular basis of ABA-mediated plant response to stress is of interest not only in basic research on plant adaptation but also in applied research on plant productivity. Maize mutant viviparous-5 (vp5, deficient in ABA biosynthesis in seeds, is a useful material for studying ABA-mediated response in maize. Due to carotenoid deficiency, vp5 endosperm is white, compared to yellow Vp5 endosperm. However, the background difference at proteome level between vp5 and Vp5 seeds is unclear. This study aimed to characterize proteome alterations of maize vp5 seeds and to identify ABA-dependent proteins during seed maturation. We compared the embryo and endosperm proteomes of vp5 and Vp5 seeds by gel-based proteomics. Up to 46 protein spots, most in embryos, were found to be differentially accumulated between vp5 and Vp5. The identified proteins included small heat shock proteins (sHSPs, late embryogenesis abundant (LEA proteins, stress proteins, storage proteins and enzymes among others. However, EMB564, the most abundant LEA protein in maize embryo, accumulated in comparable levels between vp5 and Vp5 embryos, which contrasted to previously characterized, greatly lowered expression of emb564 mRNA in vp5 embryos. Moreover, LEA proteins and sHSPs displayed differential accumulations in vp5 embryos: six out of eight identified LEA proteins decreased while nine sHSPs increased in abundance. Finally, we discussed the possible causes of global proteome alterations, especially the observed differential accumulation of identified LEA proteins and sHSPs in vp5 embryos. The data derived from this study provides new insight into ABA-dependent proteins and ABA-mediated response during maize seed maturation.

  14. Microangiopathic complications related to different alleles of ...

    African Journals Online (AJOL)

    Egyptian Journal of Biochemistry and Molecular Biology. Journal Home ... Microangiopathic complications related to different alleles of manganese superoxide dismutase gene in diabetes mellitus type 1. TM EL Masry ... 23(2) 2005: 155-167 ...

  15. The Analysis of A Frequent TMPRSS3 Allele Containing P.V116M and P.V291L in A Cis Configuration among Deaf Koreans

    Directory of Open Access Journals (Sweden)

    Ah Reum Kim

    2017-10-01

    Full Text Available We performed targeted re-sequencing to identify the genetic etiology of early-onset postlingual deafness and encountered a frequent TMPRSS3 allele harboring two variants in a cis configuration. We aimed to evaluate the pathogenicity of the allele. Among 88 cochlear implantees with autosomal recessive non-syndromic hearing loss, subjects with GJB2 and SLC26A4 mutations were excluded. Thirty-one probands manifesting early-onset postlingual deafness were sorted. Through targeted re-sequencing, we detected two families with a TMPRSS3 mutant allele containing p.V116M and p.V291L in a cis configuration, p.[p.V116M; p.V291L]. A minor allele frequency was calculated and proteolytic activity was measured. A p.[p.V116M; p.V291L] allele demonstrated a significantly higher frequency compared to normal controls and merited attention due to its high frequency (4.84%, 3/62. The first family showed a novel deleterious splice site variant—c.783-1G>A—in a trans allele, while the other showed homozygosity. The progression to deafness was noted within the first decade, suggesting DFNB10. The proteolytic activity was significantly reduced, confirming the severe pathogenicity. This frequent mutant allele significantly contributes to early-onset postlingual deafness in Koreans. For clinical implication and proper auditory rehabilitation, it is important to pay attention to this allele with a severe pathogenic potential.

  16. Pyramiding of transgenic Pm3 alleles in wheat results in improved powdery mildew resistance in the field.

    Science.gov (United States)

    Koller, Teresa; Brunner, Susanne; Herren, Gerhard; Hurni, Severine; Keller, Beat

    2018-04-01

    The combined effects of enhanced total transgene expression level and allele-specificity combination in transgenic allele-pyramided Pm3 wheat lines result in improved powdery mildew field resistance without negative pleiotropic effects. Allelic Pm3 resistance genes of wheat confer race-specific resistance to powdery mildew (Blumeria graminis f. sp. tritici, Bgt) and encode nucleotide-binding domain, leucine-rich repeat (NLR) receptors. Transgenic wheat lines overexpressing alleles Pm3a, b, c, d, f, and g have previously been generated by transformation of cultivar Bobwhite and tested in field trials, revealing varying degrees of powdery mildew resistance conferred by the transgenes. Here, we tested four transgenic lines each carrying two pyramided Pm3 alleles, which were generated by crossbreeding of lines transformed with single Pm3 alleles. All four allele-pyramided lines showed strongly improved powdery mildew resistance in the field compared to their parental lines. The improved resistance results from the two effects of enhanced total transgene expression levels and allele-specificity combinations. In contrast to leaf segment tests on greenhouse-grown seedlings, no allelic suppression was observed in the field. Plant development and yield scores of the pyramided lines were similar to the mean scores of the corresponding parental lines, and thus, the allele pyramiding did not cause any negative effects. On the contrary, in pyramided line, Pm3b × Pm3f normal plant development was restored compared to the delayed development and reduced seed set of parental line Pm3f. Allele-specific RT qPCR revealed additive transgene expression levels of the two Pm3 alleles in the pyramided lines. A positive correlation between total transgene expression level and powdery mildew field resistance was observed. In summary, allele pyramiding of Pm3 transgenes proved to be successful in enhancing powdery mildew field resistance.

  17. The DNA repair capability of cdc9, the saccharomyces cerevisiae mutant defective in DNA ligase

    International Nuclear Information System (INIS)

    Johnston, L.H.

    1979-01-01

    The cell cycle mutant, cdc9, in the yeast Saccharomyces cerevisiae is defective in DNA ligase with the consequence to be deficient in the repair of DNA damaged by methyl methane sulphonate. On the other hand survival of cdc9 after irradiation by γ-rays is little different from that of the wild-type, even after a period of stress at the restrictive temperature. The mutant cdc9 is not allelic with any known rad or mms mutants. (orig./AJ) [de

  18. Evaluation of semi-dwarf mutants in triticale and wheat breeding programmes

    International Nuclear Information System (INIS)

    Driscoll, C.J.

    1982-01-01

    A number of short-statured triticale plants were selected in M 4 following gamma-ray or EMS treatment of seed of Beagle and DR-IRA triticales. Selection for homozygous mutants will be attempted in M 5 . The Cornerstone male sterility mutant mslc is being combined with the three GA-insensitive, reduced-height mutants Gai/Rht1, Gai/Rht2 and Gai/Rht3 in order to establish a composite cross based on homozygosity of a given Gai/Rht allele. This would allow selection for minor genes for increased height on a GA-insensitive, reduced-height background. (author)

  19. The pathologic effect of a novel neomorphic Fgf9(Y162C allele is restricted to decreased vision and retarded lens growth.

    Directory of Open Access Journals (Sweden)

    Oliver Puk

    Full Text Available Fibroblast growth factor (Fgf signalling plays a crucial role in many developmental processes. Among the Fgf pathway ligands, Fgf9 (UniProt: P54130 has been demonstrated to participate in maturation of various organs and tissues including skeleton, testes, lung, heart, and eye. Here we establish a novel Fgf9 allele, discovered in a dominant N-ethyl-N-nitrosourea (ENU screen for eye-size abnormalities using the optical low coherence interferometry technique. The underlying mouse mutant line Aca12 was originally identified because of its significantly reduced lens thickness. Linkage studies located Aca12 to chromosome 14 within a 3.6 Mb spanning interval containing the positional candidate genes Fgf9 (MGI: 104723, Gja3 (MGI: 95714, and Ift88 (MGI: 98715. While no sequence differences were found in Gja3 and Ift88, we identified an A→G missense mutation at cDNA position 770 of the Fgf9 gene leading to an Y162C amino acid exchange. In contrast to previously described Fgf9 mutants, Fgf9(Y162C carriers were fully viable and did not reveal reduced body-size, male-to-female sexual reversal or skeletal malformations. The histological analysis of the retina as well as its basic functional characterization by electroretinography (ERG did not show any abnormality. However, the analysis of head-tracking response of the Fgf9(Y162C mutants in a virtual drum indicated a gene-dosage dependent vision loss of almost 50%. The smaller lenses in Fgf9(Y162C suggested a role of Fgf9 during lens development. Histological investigations showed that lens growth retardation starts during embryogenesis and continues after birth. Young Fgf9(Y162C lenses remained transparent but developed age-related cataracts. Taken together, Fgf9(Y162C is a novel neomorphic allele that initiates microphakia and reduced vision without effects on organs and tissues outside the eye. Our data point to a role of Fgf9 signalling in primary and secondary lens fiber cell growth. The results

  20. The Origin of Mutants Under Selection: How Natural Selection Mimics Mutagenesis (Adaptive Mutation)

    Science.gov (United States)

    Maisnier-Patin, Sophie; Roth, John R.

    2015-01-01

    Selection detects mutants but does not cause mutations. Contrary to this dictum, Cairns and Foster plated a leaky lac mutant of Escherichia coli on lactose medium and saw revertant (Lac+) colonies accumulate with time above a nongrowing lawn. This result suggested that bacteria might mutagenize their own genome when growth is blocked. However, this conclusion is suspect in the light of recent evidence that revertant colonies are initiated by preexisting cells with multiple copies the conjugative F′lac plasmid, which carries the lac mutation. Some plated cells have multiple copies of the simple F′lac plasmid. This provides sufficient LacZ activity to support plasmid replication but not cell division. In nongrowing cells, repeated plasmid replication increases the likelihood of a reversion event. Reversion to lac+ triggers exponential cell growth leading to a stable Lac+ revertant colony. In 10% of these plated cells, the high-copy plasmid includes an internal tandem lac duplication, which provides even more LacZ activity—sufficient to support slow growth and formation of an unstable Lac+ colony. Cells with multiple copies of the F′lac plasmid have an increased mutation rate, because the plasmid encodes the error-prone (mutagenic) DNA polymerase, DinB. Without DinB, unstable and stable Lac+ revertant types form in equal numbers and both types arise with no mutagenesis. Amplification and selection are central to behavior of the Cairns–Foster system, whereas mutagenesis is a system-specific side effect or artifact caused by coamplification of dinB with lac. Study of this system has revealed several broadly applicable principles. In all populations, gene duplications are frequent stable genetic polymorphisms, common near-neutral mutant alleles can gain a positive phenotype when amplified under selection, and natural selection can operate without cell division when variability is generated by overreplication of local genome subregions. PMID:26134316

  1. Mutant allele of rna14 in fission yeast affects pre-mRNA splicing

    Indian Academy of Sciences (India)

    transcript. Rna14 protein in budding yeast has been implicated in cleavage and ... Subsequently, genetic interaction of Rna14 with prp1 and physical .... molecular yeast techniques as described by Moreno et al. ..... To elucidate the role of Rna14 in splicing, RT-PCR analysis ..... design principles of a dynamic RNP machine.

  2. Generation of New Hairless Alleles by Genomic Engineering at the Hairless Locus in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Heiko Praxenthaler

    Full Text Available Hairless (H is the major antagonist within the Notch signalling pathway of Drosophila melanogaster. By binding to Suppressor of Hairless [Su(H] and two co-repressors, H induces silencing of Notch target genes in the absence of Notch signals. We have applied genomic engineering to create several new H alleles. To this end the endogenous H locus was replaced with an attP site by homologous recombination, serving as a landing platform for subsequent site directed integration of different H constructs. This way we generated a complete H knock out allele HattP, reintroduced a wild type H genomic and a cDNA-construct (Hgwt, Hcwt as well as two constructs encoding H proteins defective of Su(H binding (HLD, HiD. Phenotypes regarding viability, bristle and wing development were recorded, and the expression of Notch target genes wingless and cut was analysed in mutant wing discs or in mutant cell clones. Moreover, genetic interactions with Notch (N5419 and Delta (DlB2 mutants were addressed. Overall, phenotypes were largely as expected: both HLD and HiD were similar to the HattP null allele, indicating that most of H activity requires the binding of Su(H. Both rescue constructs Hgwt and Hcwt were homozygous viable without phenotype. Unexpectedly, the hemizygous condition uncovered that they were not identical to the wild type allele: notably Hcwt showed a markedly reduced activity, suggesting the presence of as yet unidentified regulatory or stabilizing elements in untranslated regions of the H gene. Interestingly, Hgwt homozygous cells expressed higher levels of H protein, perhaps unravelling gene-by-environment interactions.

  3. Allele Workbench: transcriptome pipeline and interactive graphics for allele-specific expression.

    Directory of Open Access Journals (Sweden)

    Carol A Soderlund

    Full Text Available Sequencing the transcriptome can answer various questions such as determining the transcripts expressed in a given species for a specific tissue or condition, evaluating differential expression, discovering variants, and evaluating allele-specific expression. Differential expression evaluates the expression differences between different strains, tissues, and conditions. Allele-specific expression evaluates expression differences between parental alleles. Both differential expression and allele-specific expression have been studied for heterosis (hybrid vigor, where the hybrid has improved performance over the parents for one or more traits. The Allele Workbench software was developed for a heterosis study that evaluated allele-specific expression for a mouse F1 hybrid using libraries from multiple tissues with biological replicates. This software has been made into a distributable package, which includes a pipeline, a Java interface to build the database, and a Java interface for query and display of the results. The required input is a reference genome, annotation file, and one or more RNA-Seq libraries with optional replicates. It evaluates allelic imbalance at the SNP and transcript level and flags transcripts with significant opposite directional allele-specific expression. The Java interface allows the user to view data from libraries, replicates, genes, transcripts, exons, and variants, including queries on allele imbalance for selected libraries. To determine the impact of allele-specific SNPs on protein folding, variants are annotated with their effect (e.g., missense, and the parental protein sequences may be exported for protein folding analysis. The Allele Workbench processing results in transcript files and read counts that can be used as input to the previously published Transcriptome Computational Workbench, which has a new algorithm for determining a trimmed set of gene ontology terms. The software with demo files is available

  4. Abnormal segregation of alleles in CEPH pedigree DNAs arising from allele loss in lymphoblastoid DNA.

    Science.gov (United States)

    Royle, N J; Armour, J A; Crosier, M; Jeffreys, A J

    1993-01-01

    Somatic events that result in the reduction to hemi- or homozygosity at all loci affected by the event have been identified in lymphoblastoid DNA from mothers of two CEPH families. Using suitably informative probes, the allele deficiencies were detected by the abnormal transmission of alleles from grandparents to grandchildren, with the apparent absence of the alleles from the parent. Undetected somatic deficiencies in family DNAs could result in misscoring of recombination events and consequently introduce errors into linkage analysis.

  5. Mutations in ribosomal proteins, RPL4 and RACK1, suppress the phenotype of a thermospermine-deficient mutant of Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Jun-ichi Kakehi

    Full Text Available Thermospermine acts in negative regulation of xylem differentiation and its deficient mutant of Arabidopsis thaliana, acaulis5 (acl5, shows excessive xylem formation and severe dwarfism. Studies of two dominant suppressors of acl5, sac51-d and sac52-d, have revealed that SAC51 and SAC52 encode a transcription factor and a ribosomal protein L10 (RPL10, respectively, and these mutations enhance translation of the SAC51 mRNA, which contains conserved upstream open reading frames in the 5' leader. Here we report identification of SAC53 and SAC56 responsible for additional suppressors of acl5. sac53-d is a semi-dominant allele of the gene encoding a receptor for activated C kinase 1 (RACK1 homolog, a component of the 40S ribosomal subunit. sac56-d represents a semi-dominant allele of the gene for RPL4. We show that the GUS reporter activity driven by the CaMV 35S promoter plus the SAC51 5' leader is reduced in acl5 and restored by sac52-d, sac53-d, and sac56-d as well as thermospermine. Furthermore, the SAC51 mRNA, which may be a target of nonsense-mediated mRNA decay, was found to be stabilized in these ribosomal mutants and by thermospermine. These ribosomal proteins are suggested to act in the control of uORF-mediated translation repression of SAC51, which is derepressed by thermospermine.

  6. Photorepair mutants of Arabidopsis

    International Nuclear Information System (INIS)

    Jiang, C.Z.; Yee, J.; Mitchell, D.L.; Britt, A.B.

    1997-01-01

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  7. Construindo Marcas Mutantes

    Directory of Open Access Journals (Sweden)

    Elizete De Azevedo Kreutz

    2012-09-01

    Full Text Available O presente artigo é o resultado de estudos realizados desde 2000 e busca instrumentalizar os proñssionals para a construção de Marcas Mutantes, que é   uma tendência contemporânea nas estratégias comunicacionais e de branding. Embora esta estratégia ainda não esteja consolidada, observamos que a mesma tem obtido um crescimento constante e tem sido adotadas pelas mais diferentes categorias de marcas e não apenas por aquelas direcionadas aos jovens, ao esporte, ao entretenimento, como era no principia. Com base na Hermenêutica de Profundidade de Thompson (1995, alicerçada nas pesquisas bibliográficas, de intemet, entrevistas e análise semiótica, desenhamos um método de construção de Marcas Mutantes dividido em sete fases. Como resultado, esperamos que este estudo possa auxiliar na compreensão dos processos envolvidos, ao mesmo tempo que provoque a discussão sobreo mesmo e, por consequência, o seu aprimoramento.

  8. Identification of a novel ga-related bush mutant in pumpkin (cucurbita moschata duchesne)

    International Nuclear Information System (INIS)

    Wu, T.; Cao, J.

    2015-01-01

    Pumpkin (Cucurbita moschata Duchesne) bush mutant plants were characterized by short stems. The sensitivity of pumpkin bush mutant plants to exogenous hormones was identified in this study. Results revealed that internode elongation of bush mutant plants could respond to gibberellins (GA4+7 and GA3), but not to indole acetic acid (IAA) and brassinosteroids (BR); by contrast, the mutant phenotype of bush mutant plants could not be fully rescued by GA4+7 and GA3. The internode of bush mutant plants yielded a lower KS expression level than that of vine plants. Therefore, pumpkin bush mutant plants were designated as GA-related mutant plants eliciting a partial response to GAs; the action of IAA and BR might not be involved in the internode growth of pumpkin bush mutant plants, specifically Cucurbita moschata Duch. (author)

  9. Readressing the role of Toll-like receptor-4 alleles in inflammatory bowel disease: colitis, smoking, and seroreactivity.

    Science.gov (United States)

    Manolakis, Anastassios C; Kapsoritakis, Andreas N; Kapsoritaki, Anastasia; Tiaka, Elisavet K; Oikonomou, Konstantinos A; Lotis, Vassilis; Vamvakopoulou, Dimitra; Davidi, Ioanna; Vamvakopoulos, Nikolaos; Potamianos, Spyros P

    2013-02-01

    Toll-like receptor (TLR) polymorphisms, and especially TLR-4 Asp299Gly and TLR-4 Thr399Ile, have been linked with Crohn's disease (CD) and to a lesser extent with ulcerative colitis (UC), CD behavior, and compromised seroreactivity to microbial antigens. Available data, however, are conflicting. To address these issues, the distribution of TLR-4 polymorphic alleles was assessed in patients with UC, CD, and healthy controls (HC), considering patient and disease characteristics as well as related serological markers. TLR-4 Asp299Gly and TLR-4 Thr399Ile polymorphisms were determined in 187 UC and 163 CD patients and 274 randomly selected HC. C reactive protein, anti-Saccharomyces cerevisiae mannan antibodies, anti-mannobioside carbohydrate antibodies, anti-laminariobioside carbohydrate antibodies IgG, and anti-chitobioside carbohydrate antibodies (ACCA) IgA levels were also assessed. UC and especially pancolitis patients carried the mutant alleles more frequently compared to CD patients and HC or UC patients with different disease extents (P = 0.002 and P ACCA IgA were lower in inflammatory bowel disease (IBD) patients carrying the mutant compared to those with wild-type alleles (0.075 ACCA IgA levels. Smoking reduces the extent of UC, even in the presence of mutant alleles.

  10. Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Woodcock, M Ryan; Vaughn-Wolfe, Jennifer; Elias, Alexandra; Kump, D Kevin; Kendall, Katharina Denise; Timoshevskaya, Nataliya; Timoshevskiy, Vladimir; Perry, Dustin W; Smith, Jeramiah J; Spiewak, Jessica E; Parichy, David M; Voss, S Randal

    2017-01-31

    The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning-candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyr a ) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyr a has a 142 bp deletion and similar engineered alleles recapitulated the albino phenotype. Finally, we show that historical introgression of tyr a significantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl.

  11. UV-induced reversion of his4 frameshift mutations in rad6, rev1, and rev3 mutants of yeast.

    Science.gov (United States)

    Lawrence, C W; O'Brien, T; Bond, J

    1984-01-01

    The UV-induced reversion of two his4 frameshift alleles was much reduced in rad6 mutants of Saccharomyces cerevisiae, an observation that is consistent with the hypothesis that RAD6 function is required for the induction of all types of genetic alteration in misrepair mutagenesis. The reversion of these his4 alleles, together with two others of the same type, was also reduced in rev1 and rev3 mutant strains; in these, however, the extent of the reduction varied considerably with test allele used, in a manner analogous to the results in these strains for base repair substitution test alleles. The general features of UV-induced frameshift and substitution mutagenesis therefore appear quite similar, indicating that they may depend on related processes. If this conclusion is correct, greater attention must be given to integrating models which account for the production of nucleotide additions and deletions into those concerning misrepair mutagenesis.

  12. The agronomic characters of a high protein rice mutant

    International Nuclear Information System (INIS)

    Harn, C.; Won, J.L.; Choi, K.T.

    1975-01-01

    Mutant lines (M 5 -M 9 ) of macro-phenotypic traits from several varieties were screened for the protein content. Mutant 398 (M 9 ) is one of the high protein mutants selected from Hokwang. Three years' tests revealed that it has a high protein line under any condition of cultivation. Except for early maturity and short culmness, other agronomic and yield characters were similar to the original variety. There was no difference between the mutant 398 and its mother variety in grain shape and weight, and also the size and protein content of the embryo. The high protein content of the mutant is attributable to the increase of protein in the endosperm. About 150 normal-looking or a few days-earlier-maturing selections were made from Jinheung variety in the M 3 and screened for protein. Promising lines in terms of the plant type, yield and protein were obtained. (author)

  13. Isozyme differences in barley mutants

    Energy Technology Data Exchange (ETDEWEB)

    AI-Jibouri, A A.M.; Dham, K M [Department of Botany, Nuclear Research Centre, Baghdad (Iraq)

    1990-01-01

    Full text: Thirty mutants (M{sub 11}) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  14. Isozyme differences in barley mutants

    International Nuclear Information System (INIS)

    AI-Jibouri, A.A.M.; Dham, K.M.

    1990-01-01

    Full text: Thirty mutants (M 11 ) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

  15. Estimated allele substitution effects underlying genomic evaluation models depend on the scaling of allele counts

    NARCIS (Netherlands)

    Bouwman, Aniek C.; Hayes, Ben J.; Calus, Mario P.L.

    2017-01-01

    Background: Genomic evaluation is used to predict direct genomic values (DGV) for selection candidates in breeding programs, but also to estimate allele substitution effects (ASE) of single nucleotide polymorphisms (SNPs). Scaling of allele counts influences the estimated ASE, because scaling of

  16. Natural Arabidopsis brx loss-of-function alleles confer root adaptation to acidic soil.

    Science.gov (United States)

    Gujas, Bojan; Alonso-Blanco, Carlos; Hardtke, Christian S

    2012-10-23

    Soil acidification is a major agricultural problem that negatively affects crop yield. Root systems counteract detrimental passive proton influx from acidic soil through increased proton pumping into the apoplast, which is presumably also required for cell elongation and stimulated by auxin. Here, we found an unexpected impact of extracellular pH on auxin activity and cell proliferation rate in the root meristem of two Arabidopsis mutants with impaired auxin perception, axr3 and brx. Surprisingly, neutral to slightly alkaline media rescued their severely reduced root (meristem) growth by stimulating auxin signaling, independent of auxin uptake. The finding that proton pumps are hyperactive in brx roots could explain this phenomenon and is consistent with more robust growth and increased fitness of brx mutants on overly acidic media or soil. Interestingly, the original brx allele was isolated from a natural stock center accession collected from acidic soil. Our discovery of a novel brx allele in accessions recently collected from another acidic sampling site demonstrates the existence of independently maintained brx loss-of-function alleles in nature and supports the notion that they are advantageous in acidic soil pH conditions, a finding that might be exploited for crop breeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. ENU mutagenesis reveals that Notchless homolog 1 (Drosophila affects Cdkn1a and several members of the Wnt pathway during murine pre-implantation development

    Directory of Open Access Journals (Sweden)

    Lossie Amy C

    2012-12-01

    Full Text Available Abstract Background Our interests lie in determining the genes and genetic pathways that are important for establishing and maintaining maternal-fetal interactions during pregnancy. Mutation analysis targeted to a 34 Mb domain flanked by Trp53 and Wnt3 demonstrates that this region of mouse chromosome 11 contains a large number of essential genes. Two mutant alleles (l11Jus1 and l11Jus4, which fall into the same complementation group, survive through implantation but fail prior to gastrulation. Results Through a positional cloning strategy, we discovered that these homozygous mutant alleles contain non-conservative missense mutations in the Notchless homolog 1 (Drosophila (Nle1 gene. NLE1 is a member of the large WD40-repeat protein family, and is thought to signal via the canonical NOTCH pathway in vertebrates. However, the phenotype of the Nle1 mutant mice is much more severe than single Notch receptor mutations or even in animals in which NOTCH signaling is blocked. To test the hypothesis that NLE1 functions in multiple signaling pathways during pre-implantation development, we examined expression of multiple Notch downstream target genes, as well as select members of the Wnt pathway in wild-type and mutant embryos. We did not detect altered expression of any primary members of the Notch pathway or in Notch downstream target genes. However, our data reveal that Cdkn1a, a NOTCH target, was upregulated in Nle1 mutants, while several members of the Wnt pathway are downregulated. In addition, we found that Nle1 mutant embryos undergo caspase-mediated apoptosis as hatched blastocysts, but not as morulae or blastocysts. Conclusions Taken together, these results uncover potential novel functions for NLE1 in the WNT and CDKN1A pathways during embryonic development in mammals.

  18. Field Performance of Five Soybean Mutants Under Drought Stress Conditions and Molecular Analysis Using SSR Markers

    Directory of Open Access Journals (Sweden)

    Y Yuliasti

    2017-08-01

    Full Text Available The objectives of this research wereto evaluate (1 the performance of soybean mutant lines under drought stress conditions, and(2 the genetic diversity and relationship among the mutant lines using SSR markers.The field evaluation was conducted during the dry season of 2011 and 2012 at the experimental Farm of Mataram University, West Nusa Tenggara, Indonesia. The field experiment was set up in a randomized block design. Ten mutant lines and two control varieties were evaluated in four replications. Genetic distance among evaluated lines were determined based on allelic diversity analysis using 40 simple sequence repeat (SSR loci. Under drought stress conditions, two mutant lines, Kdl3 and Kdl8,showed a better performance compared to the other ones. The high yielding mutant lines were Kdl3and Kdl8, which yielded 1.75 t ha-1and 1.69 t ha-1, respectively, compared to the parent and national control, Panderman 1.43 t ha-1 and Muria 1.32 t ha-1. These mutant linesrequired 30.75 to 32days to flower and 79.75 to 83.75 day to harvest with relatively short plant height 28.25 and 23.35 cmrespectively. Those mutant characters were better than those of the other three mutants, the original parents, and the control soybean species. Since the evaluated soybean mutant lines yielded more under drought stress conditions than the standard varieties, they can be used and registered as drought-tolerant soybean mutants. Moreover, the evaluated soybean accessions showed a wide genetic distance. The accessions were clustered into two groups according to their genetic background, namelygroup I (the Panderman with three mutant lines and group II (the Muria with two mutant lines. Twenty-three out of 40 evaluated SSR loci, including AW31, BE806, CMAC7L, S080, S126, S57, S171, S224, S285, S294, S393, S294, S383, S511, S511, S520, S540, S547, S551, S571, S577, and S578, provided polymorphic alleles between the parents and their mutants and could be used to differentiate

  19. Allelic genealogies in sporophytic self-incompatibility systems in plants

    DEFF Research Database (Denmark)

    Schierup, Mikkel Heide; Vekemans, Xavier; Christiansen, Freddy Bugge

    1998-01-01

    , alleles act codominantly in both pollen and style, in the SSIdom model, alleles form a dominance hierarchy, and in SSIdomcod, alleles are codominant in the style and show a dominance hierarchy in the pollen. Coalescence times of alleles rarely differ more than threefold from those under gametophytic self...

  20. The restriction-modification genes of Escherichia coli K-12 may not be selfish: they do not resist loss and are readily replaced by alleles conferring different specificities.

    Science.gov (United States)

    O'Neill, M; Chen, A; Murray, N E

    1997-12-23

    Type II restriction and modification (R-M) genes have been described as selfish because they have been shown to impose selection for the maintenance of the plasmid that encodes them. In our experiments, the type I R-M system EcoKI does not behave in the same way. The genes specifying EcoKI are, however, normally residents of the chromosome and therefore our analyses were extended to monitor the deletion of chromosomal genes rather than loss of plasmid vector. If EcoKI were to behave in the same way as the plasmid-encoded type II R-M systems, the loss of the relevant chromosomal genes by mutation or recombination should lead to cell death because the cell would become deficient in modification enzyme and the bacterial chromosome would be vulnerable to the restriction endonuclease. Our data contradict this prediction; they reveal that functional type I R-M genes in the chromosome are readily replaced by mutant alleles and by alleles encoding a type I R-M system of different specificity. The acquisition of allelic genes conferring a new sequence specificity, but not the loss of the resident genes, is dependent on the product of an unlinked gene, one predicted [Prakash-Cheng, A., Chung, S. S. & Ryu, J. (1993) Mol. Gen. Genet. 241, 491-496] to be relevant to control of expression of the genes that encode EcoKI. Our evidence suggests that not all R-M systems are evolving as "selfish" units; rather, the diversity and distribution of the family of type I enzymes we have investigated require an alternative selective pressure.

  1. Histological and Molecular Characterization of Grape Early Ripening Bud Mutant

    Directory of Open Access Journals (Sweden)

    Da-Long Guo

    2016-01-01

    Full Text Available An early ripening bud mutant was analyzed based on the histological, SSR, and methylation-sensitive amplified polymorphism (MSAP analysis and a layer-specific approach was used to investigate the differentiation between the bud mutant and its parent. The results showed that the thickness of leaf spongy tissue of mutant (MT is larger than that of wild type (WT and the differences are significant. The mean size of cell layer L2 was increased in the mutant and the difference is significant. The genetic background of bud mutant revealed by SSR analysis is highly uniform to its parent; just the variations from VVS2 SSR marker were detected in MT. The total methylation ratio of MT is lower than that of the corresponding WT. The outside methylation ratio in MT is much less than that in WT; the average inner methylation ratio in MT is larger than that in WT. The early ripening bud mutant has certain proportion demethylation in cell layer L2. All the results suggested that cell layer L2 of the early ripening bud mutant has changed from the WT. This study provided the basis for a better understanding of the characteristic features of the early ripening bud mutant in grape.

  2. Allelic Dropout in the ENG Gene, Affecting the Results of Genetic Testing in Hereditary Hemorrhagic Telangiectasia

    DEFF Research Database (Denmark)

    Tørring, Pernille M; Kjeldsen, A.D.; Ousager, L.B.

    2012-01-01

    Background: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal-dominant vascular disorder with three disease-causing genes identified to date: ENG, ACVRL1, and SMAD4. We report an HHT patient with allelic dropout that on routine sequence analysis for a known mutation in the family (c.817......-3T>G in ENG) initially seemed to be homozygous for the mutation. Aim: To explore the possibility of allelic dropout causing a false result in this patient. Methods: Mutation analysis of additional family members was performed and haplotype analysis carried out. New primers were designed to reveal...... the presence of a possible sequence variant, which could explain the presumed allelic dropout. Results: Allelic dropout caused by a six-nucleotide duplication close to the standard reverse primer was the assumed cause of a false homozygous diagnosis. Conclusion: Sequence variants outside of the primer regions...

  3. Genetic analysis of rice semidwarf mutant Tad-M-1

    International Nuclear Information System (INIS)

    Wang Naiyuan; Yang Rencui

    1995-01-01

    This paper dealed with the inheritance of the rice semidwarf of Tad-M-,a mutant line bred from traditional indica rice Variety Tadukan by radiation. The results indicated that semidwarf of Tad-M-1 was controlled by one pair of recessive gene, which was nonallelic to sd-1 gene of variety Aijiaonante and sd-g gene of variety Xinguiai and allelic to the semidwarf gene of Yunnan japonica variety Xueheaizao and Sichuan indica variety Yizila.The possible uses of Tad-M-1 in rice breeding was also discussed

  4. Impairment of Infectivity and Immunoprotective Effect of a LYT1 Null Mutant of Trypanosoma cruzi▿

    Science.gov (United States)

    Zago, M. Paola; Barrio, Alejandra B.; Cardozo, Rubén M.; Duffy, Tomás; Schijman, Alejandro G.; Basombrío, Miguel A.

    2008-01-01

    Trypanosoma cruzi infection of host cells is a complex process in which many proteins participate but only a few of these proteins have been identified experimentally. One parasite factor likely to be involved is the protein product of LYT1, a single-copy gene cloned, sequenced, and characterized by Manning-Cela et al. (Infect. Immun. 69:3916-3923, 2001). This gene was potentially associated with infectivity, since the deletion of both LYT1 alleles in the CL Brenner strain (the wild type [WT]) resulted in a null mutant T. cruzi clone (L16) that shows an attenuated phenotype in cell culture models. The aim of this work was to characterize the infective behavior of L16 in the insect vector and murine models. The infection of adult Swiss mice with 103 trypomastigotes of both clones revealed a significant reduction in infective behavior of L16, as shown by direct parasitemia, spleen index, and quantitation of tissue parasite burden, suggesting the loss of virulence in the null mutant clone. Although L16 blood counts were almost undetectable, blood-based PCRs indicated the presence of latent and persistent infection during all of the study period and epimastigotes were reisolated from hemocultures until 12 months postinfection. Nevertheless, virulence was not restored in L16 by serial passages in mice, and reisolated parasites lacking the LYT1 gene and bearing the antibiotic resistance genes revealed the stability of the genetic manipulation. Histopathological studies showed a strong diminution in the muscle inflammatory response triggered by L16 compared to that triggered by the WT group, consistent with a lower tissue parasite load. A strong protection against a virulent challenge in both L16- and WT-infected mice was observed; however, the immunizing infection by the genetically modified parasite was highly attenuated. PMID:17938222

  5. Evaluation of tall rice mutant

    International Nuclear Information System (INIS)

    Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

    1989-01-01

    One tall mutant (Mut NS1) of rice variety Nizersail was put to multilocation on-farm trial. It showed improvement over the parent in respect of by earlier maturity and higher grain yield at all locations and thus it appears as an improved mutant of Nizersail. (author). 6 refs

  6. Identification and Map-Based Cloning of the Light-Induced Lesion Mimic Mutant 1 (LIL1) Gene in Rice.

    Science.gov (United States)

    Zhou, Qian; Zhang, Zhifei; Liu, Tiantian; Gao, Bida; Xiong, Xingyao

    2017-01-01

    The hypersensitive response (HR) is a mechanism by which plants prevent the spread of pathogen. Despite extensive study, the molecular mechanisms underlying HR remain poorly understood. Lesion mimic mutants (LMMs), such as LIL1 that was identified in an ethylmethane sulfonate mutagenized population of Indica rice ( Oryza sativa L. ssp. Indica ) 93-11, can be used to study the HR. Under natural field conditions, the leaves of LIL1 mutant plants exhibited light-induced, small, rust-red lesions that first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. Histochemical staining indicated that LIL1 lesions displayed an abnormal accumulation of reactive oxygen species (ROS) and resulted from programmed cell death (PCD). The LIL1 mutants also displayed increased expression of defense-related genes and enhanced resistance to rice blast fungus ( Magnaporthe grisea ). Genetic analysis showed that mutation of LIL1 created a semi-dominant allele. Using 1,758 individuals in the F 2 population, LIL1 was mapped in a 222.3 kb region on the long arm of chromosome 7. That contains 12 predicted open reading frames (ORFs). Sequence analysis of these 12 candidate genes revealed a G to A base substitution in the fourth exon of LOC_Os07g30510, a putative cysteine-rich receptor-like kinase (CRK), which led to an amino acid change (Val 429 to Ile) in the LIL1 protein. Comparison of the transcript accumulation of the 12 candidate genes between LIL1 and 93-11 revealed that LOC_Os07g30510 was up-regulated significantly in LIL1 . Overexpression of the LOC_Os07g30510 gene from LIL1 induced a LIL1 -like lesion phenotype in Nipponbare. Thus, LIL1 is a novel LMM in rice that will facilitate the further study of the molecular mechanisms of HR and the rice blast resistance.

  7. Structural, stability, dynamic and binding properties of the ALS-causing T46I mutant of the hVAPB MSP domain as revealed by NMR and MD simulations.

    Directory of Open Access Journals (Sweden)

    Shixiong Lua

    Full Text Available T46I is the second mutation on the hVAPB MSP domain which was recently identified from non-Brazilian kindred to cause a familial amyotrophic lateral sclerosis (ALS. Here using CD, NMR and molecular dynamics (MD simulations, we characterized the structure, stability, dynamics and binding capacity of the T46I-MSP domain. The results reveal: 1 unlike P56S which we previously showed to completely eliminate the native MSP structure, T46I leads to no significant disruption of the native secondary and tertiary structures, as evidenced from its far-UV CD spectrum, as well as Cα and Cβ NMR chemical shifts. 2 Nevertheless, T46I does result in a reduced thermodynamic stability and loss of the cooperative urea-unfolding transition. As such, the T46I-MSP domain is more prone to aggregation than WT at high protein concentrations and temperatures in vitro, which may become more severe in the crowded cellular environments. 3 T46I only causes a 3-fold affinity reduction to the Nir2 peptide, but a significant elimination of its binding to EphA4. 4 EphA4 and Nir2 peptide appear to have overlapped binding interfaces on the MSP domain, which strongly implies that two signaling networks may have a functional interplay in vivo. 5 As explored by both H/D exchange and MD simulations, the MSP domain is very dynamic, with most loop residues and many residues on secondary structures highly fluctuated or/and exposed to bulk solvent. Although T46I does not alter overall dynamics, it does trigger increased dynamics of several local regions of the MSP domain which are implicated in binding to EphA4 and Nir2 peptide. Our study provides the structural and dynamic understanding of the T46I-causing ALS; and strongly highlights the possibility that the interplay of two signaling networks mediated by the FFAT-containing proteins and Eph receptors may play a key role in ALS pathogenesis.

  8. Investigations on gamma ray induced chlorophyll variegated mutants

    International Nuclear Information System (INIS)

    Datta, S.K.; Dwivedi, A.K.; Banerji, B.K.

    1995-01-01

    Considering economic importance of chlorophyll variegation in floriculture trade an attempt was made for cytological, anatomical and biochemical analysis of four Bougainvillea and Lantana depressa chlorophyll variegated mutants for better and clear understanding of origin of chlorophyll variegation. No cytological evidence could be detected for their origin. Anatomical and biochemical examinations revealed that chlorophyll variegation in these mutants were due to changes in biosynthesis pathways and time of chlorophyll synthesis in palisade and spongy mesophyll cells. (author). 7 refs., 3 figs., 3 tabs

  9. RHD alleles in the Tunisian population

    Science.gov (United States)

    Ouchari, Mouna; Jemni-Yaacoub, Saloua; Chakroun, Taher; Abdelkefi, Saida; Houissa, Batoul; Hmida, Slama

    2013-01-01

    Background: A comprehensive survey of RHD alleles in Tunisia population was lacking. The aim of this study was to use a multiplex RHD typing assay for simultaneous detection of partial D especially with RHD/RHCE deoxyribonucleic acid (DNA) sequence exchange mechanism and some weak D alleles. Materials and Methods: Six RHD specific primer sets were designed to amplify RHD exons 3, 4, 5, 6, 7 and 9. DNA from 2000 blood donors (1777 D+ and 223 D-) from several regions was selected for RHD genotyping using a PCR multiplex assay. Further molecular investigations were done to characterize the RHD variants that were identified by the PCR multiplex assay. Results: In the 1777 D+ samples, only 10 individuals showed the absence of amplification of exons 4 and 5 that were subsequently identified by PCR-SSP as weak D type 4 variants. No hybrid allele was detected. In the 223 D-, RHD amplification of some exons was observed only in 5 samples: 4 individuals expressed only RHD exon 9, and one subject lacking exons 4 and 5. These samples were then screened by PCR-SSPs on d(C) ces and weak D type 4, respectively. Conclusion: The weak D type 4 appears to be the most common D variant allele. We have not found any partial D variant. Findings also indicated that RHD gene deletion is the most prevalent cause of the D- phenotype in the Tunisian population. PMID:24014941

  10. Diversity of Lactase Persistence Alleles in Ethiopia

    DEFF Research Database (Denmark)

    Jones, BL; Raga, TO; Liebert, Anke

    2013-01-01

    The persistent expression of lactase into adulthood in humans is a recent genetic adaptation that allows the consumption of milk from other mammals after weaning. In Europe, a single allele (−13910∗T, rs4988235) in an upstream region that acts as an enhancer to the expression of the lactase gene ...

  11. Semi-dwarf mutant lines of hexaploid triticale

    International Nuclear Information System (INIS)

    Pidra, M.

    1989-01-01

    A spring form of hexaploid secondary triticale ADD 143/71, bred by MOGILEVA at the Plant Breeding Station at Uhretice was used for the mutagen treatment. The mutation experiment started in 1979. Seeds were treated with a 0.8 mM water solution of N-methyl-N-nitrosourea (MNH) (CETL and RELICHOVA, unpublished). From 180 M 1 plants, one spike was harvested per plant. A random sample of these seeds was sown as M 2 in 1980 and several plants with shorter main culm were selected. Selfed progenies of eight mutant plants designated ADD 143-m1, ADD 143-m2, ADD 143-m3 etc. were further tested in M 3 and M 4 . There were significant differences in culm length and in some other characters between the original line and the mutant lines. Especially the line m8 looks like a promising source of semi-dwarfness for breeding programmes of hexaploid triticale. During 1985-1987 genetic analysis was performed on the ADD 143/71 and the mutant lines m2, m6, m7 and m8, which suggest that their mutant genes are allelic and recessive

  12. Whole-Genome Sequencing of Sordaria macrospora Mutants Identifies Developmental Genes.

    Science.gov (United States)

    Nowrousian, Minou; Teichert, Ines; Masloff, Sandra; Kück, Ulrich

    2012-02-01

    The study of mutants to elucidate gene functions has a long and successful history; however, to discover causative mutations in mutants that were generated by random mutagenesis often takes years of laboratory work and requires previously generated genetic and/or physical markers, or resources like DNA libraries for complementation. Here, we present an alternative method to identify defective genes in developmental mutants of the filamentous fungus Sordaria macrospora through Illumina/Solexa whole-genome sequencing. We sequenced pooled DNA from progeny of crosses of three mutants and the wild type and were able to pinpoint the causative mutations in the mutant strains through bioinformatics analysis. One mutant is a spore color mutant, and the mutated gene encodes a melanin biosynthesis enzyme. The causative mutation is a G to A change in the first base of an intron, leading to a splice defect. The second mutant carries an allelic mutation in the pro41 gene encoding a protein essential for sexual development. In the mutant, we detected a complex pattern of deletion/rearrangements at the pro41 locus. In the third mutant, a point mutation in the stop codon of a transcription factor-encoding gene leads to the production of immature fruiting bodies. For all mutants, transformation with a wild type-copy of the affected gene restored the wild-type phenotype. Our data demonstrate that whole-genome sequencing of mutant strains is a rapid method to identify developmental genes in an organism that can be genetically crossed and where a reference genome sequence is available, even without prior mapping information.

  13. Characterization of new mutants in the early part of the yeast secretory pathway isolated by a [3H]mannose suicide selection

    International Nuclear Information System (INIS)

    Newman, A.P.; Ferro-Novick, S.

    1987-01-01

    We have adapted a [ 3 H]mannose suicide selection to identify mutations in additional genes which function in the early part of the yeast secretory pathway. Thus far this protocol has led to the identification of two new genes which are implicated in this process, as well as additional alleles of previously identified genes. The new mutants, bet1 and bet2, are temperature sensitive for growth and protein transport. Thin section analysis has revealed the accumulation of a network of endoplasmic reticulum (ER) at the restrictive temperature (37 0 C). Precursors of exported proteins that accumulate in the cell at 37 0 C are terminally core glycosylated. These observations suggest that the transport of precursors is blocked subsequent to translocation into the ER but before entry into the Golgi apparatus. The bet1 and bet2 mutants define two new complementation groups which have the same properties as previously identified ER-accumulating mutants. This and previous findings suggest that protein exit from the ER and entry into the Golgi apparatus is a complex process requiring at least 11 genes

  14. Functional conservation of the Drosophila gooseberry gene and its evolutionary alleles.

    Directory of Open Access Journals (Sweden)

    Wei Liu

    Full Text Available The Drosophila Pax gene gooseberry (gsb is required for development of the larval cuticle and CNS, survival to adulthood, and male fertility. These functions can be rescued in gsb mutants by two gsb evolutionary alleles, gsb-Prd and gsb-Pax3, which express the Drosophila Paired and mouse Pax3 proteins under the control of gooseberry cis-regulatory region. Therefore, both Paired and Pax3 proteins have conserved all the Gsb functions that are required for survival of embryos to fertile adults, despite the divergent primary sequences in their C-terminal halves. As gsb-Prd and gsb-Pax3 uncover a gsb function involved in male fertility, construction of evolutionary alleles may provide a powerful strategy to dissect hitherto unknown gene functions. Our results provide further evidence for the essential role of cis-regulatory regions in the functional diversification of duplicated genes during evolution.

  15. Characterization of a Novel MMS-Sensitive Allele of Schizosaccharomyces pombe mcm4+

    Science.gov (United States)

    Ranatunga, Nimna S.; Forsburg, Susan L.

    2016-01-01

    The minichromosome maintenance (MCM) complex is the conserved helicase motor of the eukaryotic replication fork. Mutations in the Mcm4 subunit are associated with replication stress and double strand breaks in multiple systems. In this work, we characterize a new temperature-sensitive allele of Schizosaccharomyces pombe mcm4+. Uniquely among known mcm4 alleles, this mutation causes sensitivity to the alkylation damaging agent methyl methanesulfonate (MMS). Even in the absence of treatment or temperature shift, mcm4-c106 cells show increased repair foci of RPA and Rad52, and require the damage checkpoint for viability, indicating genome stress. The mcm4-c106 mutant is synthetically lethal with mutations disrupting fork protection complex (FPC) proteins Swi1 and Swi3. Surprisingly, we found that the deletion of rif1+ suppressed the MMS-sensitive phenotype without affecting temperature sensitivity. Together, these data suggest that mcm4-c106 destabilizes replisome structure. PMID:27473316

  16. A forward genetic screen reveals essential and non-essential RNAi factors in Paramecium tetraurelia

    Science.gov (United States)

    Marker, Simone; Carradec, Quentin; Tanty, Véronique; Arnaiz, Olivier; Meyer, Eric

    2014-01-01

    In most eukaryotes, small RNA-mediated gene silencing pathways form complex interacting networks. In the ciliate Paramecium tetraurelia, at least two RNA interference (RNAi) mechanisms coexist, involving distinct but overlapping sets of protein factors and producing different types of short interfering RNAs (siRNAs). One is specifically triggered by high-copy transgenes, and the other by feeding cells with double-stranded RNA (dsRNA)-producing bacteria. In this study, we designed a forward genetic screen for mutants deficient in dsRNA-induced silencing, and a powerful method to identify the relevant mutations by whole-genome sequencing. We present a set of 47 mutant alleles for five genes, revealing two previously unknown RNAi factors: a novel Paramecium-specific protein (Pds1) and a Cid1-like nucleotidyl transferase. Analyses of allelic diversity distinguish non-essential and essential genes and suggest that the screen is saturated for non-essential, single-copy genes. We show that non-essential genes are specifically involved in dsRNA-induced RNAi while essential ones are also involved in transgene-induced RNAi. One of the latter, the RNA-dependent RNA polymerase RDR2, is further shown to be required for all known types of siRNAs, as well as for sexual reproduction. These results open the way for the dissection of the genetic complexity, interconnection, mechanisms and natural functions of RNAi pathways in P. tetraurelia. PMID:24860163

  17. Estimating the probability of allelic drop-out of STR alleles in forensic genetics

    DEFF Research Database (Denmark)

    Tvedebrink, Torben; Eriksen, Poul Svante; Mogensen, Helle Smidt

    2009-01-01

    In crime cases with available DNA evidence, the amount of DNA is often sparse due to the setting of the crime. In such cases, allelic drop-out of one or more true alleles in STR typing is possible. We present a statistical model for estimating the per locus and overall probability of allelic drop......-out using the results of all STR loci in the case sample as reference. The methodology of logistic regression is appropriate for this analysis, and we demonstrate how to incorporate this in a forensic genetic framework....

  18. Allelic Variation of Bile Salt Hydrolase Genes in Lactobacillus salivarius Does Not Determine Bile Resistance Levels▿ †

    Science.gov (United States)

    Fang, Fang; Li, Yin; Bumann, Mario; Raftis, Emma J.; Casey, Pat G.; Cooney, Jakki C.; Walsh, Martin A.; O'Toole, Paul W.

    2009-01-01

    Commensal lactobacilli frequently produce bile salt hydrolase (Bsh) enzymes whose roles in intestinal survival are unclear. Twenty-six Lactobacillus salivarius strains from different sources all harbored a bsh1 allele on their respective megaplasmids. This allele was related to the plasmid-borne bsh1 gene of the probiotic strain UCC118. A second locus (bsh2) was found in the chromosomes of two strains that had higher bile resistance levels. Four Bsh1-encoding allele groups were identified, defined by truncations or deletions involving a conserved residue. In vitro analyses showed that this allelic variation was correlated with widely varying bile deconjugation phenotypes. Despite very low activity of the UCC118 Bsh1 enzyme, a mutant lacking this protein had significantly lower bile resistance, both in vitro and during intestinal transit in mice. However, the overall bile resistance phenotype of this and other strains was independent of the bsh1 allele type. Analysis of the L. salivarius transcriptome upon exposure to bile and cholate identified a multiplicity of stress response proteins and putative efflux proteins that appear to broadly compensate for, or mask, the effects of allelic variation of bsh genes. Bsh enzymes with different bile-degrading kinetics, though apparently not the primary determinants of bile resistance in L. salivarius, may have additional biological importance because of varying effects upon bile as a signaling molecule in the host. PMID:19592587

  19. Natural host genetic resistance to lentiviral CNS disease: a neuroprotective MHC class I allele in SIV-infected macaques.

    Directory of Open Access Journals (Sweden)

    Joseph L Mankowski

    Full Text Available Human immunodeficiency virus (HIV infection frequently causes neurologic disease even with anti-retroviral treatment. Although associations between MHC class I alleles and acquired immunodeficiency syndrome (AIDS have been reported, the role MHC class I alleles play in restricting development of HIV-induced organ-specific diseases, including neurologic disease, has not been characterized. This study examined the relationship between expression of the MHC class I allele Mane-A*10 and development of lentiviral-induced central nervous system (CNS disease using a well-characterized simian immunodeficiency (SIV/pigtailed macaque model. The risk of developing CNS disease (SIV encephalitis was 2.5 times higher for animals that did not express the MHC class I allele Mane-A*10 (P = 0.002; RR = 2.5. Animals expressing the Mane-A*10 allele had significantly lower amounts of activated macrophages, SIV RNA, and neuronal dysfunction in the CNS than Mane-A*10 negative animals (P<0.001. Mane-A*10 positive animals with the highest CNS viral burdens contained SIV gag escape mutants at the Mane-A*10-restricted KP9 epitope in the CNS whereas wild type KP9 sequences dominated in the brain of Mane-A*10 negative animals with comparable CNS viral burdens. These concordant findings demonstrate that particular MHC class I alleles play major neuroprotective roles in lentiviral-induced CNS disease.

  20. The Pleiotropic Phenotype of Apc Mutations in the Mouse: Allele Specificity and Effects of the Genetic Background

    Science.gov (United States)

    Halberg, Richard B.; Chen, Xiaodi; Amos-Landgraf, James M.; White, Alanna; Rasmussen, Kristin; Clipson, Linda; Pasch, Cheri; Sullivan, Ruth; Pitot, Henry C.; Dove, William F.

    2008-01-01

    Familial adenomatous polyposis (FAP) is a human cancer syndrome characterized by the development of hundreds to thousands of colonic polyps and extracolonic lesions including desmoid fibromas, osteomas, epidermoid cysts, and congenital hypertrophy of the pigmented retinal epithelium. Afflicted individuals are heterozygous for mutations in the APC gene. Detailed investigations of mice heterozygous for mutations in the ortholog Apc have shown that other genetic factors strongly influence the phenotype. Here we report qualitative and quantitative modifications of the phenotype of Apc mutants as a function of three genetic variables: Apc allele, p53 allele, and genetic background. We have found major differences between the Apc alleles Min and 1638N in multiplicity and regionality of intestinal tumors, as well as in incidence of extracolonic lesions. By contrast, Min mice homozygous for either of two different knockout alleles of p53 show similar phenotypic effects. These studies illustrate the classic principle that functional genetics is enriched by assessing penetrance and expressivity with allelic series. The mouse permits study of an allelic gene series on multiple genetic backgrounds, thereby leading to a better understanding of gene action in a range of biological processes. PMID:18723878

  1. Human liver cell trafficking mutants: characterization and whole exome sequencing.

    Directory of Open Access Journals (Sweden)

    Fei Yuan

    Full Text Available The HuH7 liver cell mutant Trf1 is defective in membrane trafficking and is complemented by the casein kinase 2α subunit CK2α''. Here we identify characteristic morphologies, trafficking and mutational changes in six additional HuH7 mutants Trf2-Trf7. Trf1 cells were previously shown to be severely defective in gap junction functions. Using a Lucifer yellow transfer assay, remarkable attenuation of gap junction communication was revealed in each of the mutants Trf2-Trf7. Electron microscopy and light microscopy of thiamine pyrophosphatase showed that several mutants exhibited fragmented Golgi apparatus cisternae compared to parental HuH7 cells. Intracellular trafficking was investigated using assays of transferrin endocytosis and recycling and VSV G secretion. Surface binding of transferrin was reduced in all six Trf2-Trf7 mutants, which generally correlated with the degree of reduced expression of the transferrin receptor at the cell surface. The mutants displayed the same transferrin influx rates as HuH7, and for efflux rate, only Trf6 differed, having a slower transferrin efflux rate than HuH7. The kinetics of VSV G transport along the exocytic pathway were altered in Trf2 and Trf5 mutants. Genetic changes unique to particular Trf mutants were identified by exome sequencing, and one was investigated in depth. The novel mutation Ile34Phe in the GTPase RAB22A was identified in Trf4. RNA interference knockdown of RAB22A or overexpression of RAB22AI34F in HuH7 cells caused phenotypic changes characteristic of the Trf4 mutant. In addition, the Ile34Phe mutation reduced both guanine nucleotide binding and hydrolysis activities of RAB22A. Thus, the RAB22A Ile34Phe mutation appears to contribute to the Trf4 mutant phenotype.

  2. Centromere replication timing determines different forms of genomic instability in Saccharomyces cerevisiae checkpoint mutants during replication stress.

    Science.gov (United States)

    Feng, Wenyi; Bachant, Jeff; Collingwood, David; Raghuraman, M K; Brewer, Bonita J

    2009-12-01

    Yeast replication checkpoint mutants lose viability following transient exposure to hydroxyurea, a replication-impeding drug. In an effort to understand the basis for this lethality, we discovered that different events are responsible for inviability in checkpoint-deficient cells harboring mutations in the mec1 and rad53 genes. By monitoring genomewide replication dynamics of cells exposed to hydroxyurea, we show that cells with a checkpoint deficient allele of RAD53, rad53K227A, fail to duplicate centromeres. Following removal of the drug, however, rad53K227A cells recover substantial DNA replication, including replication through centromeres. Despite this recovery, the rad53K227A mutant fails to achieve biorientation of sister centromeres during recovery from hydroxyurea, leading to secondary activation of the spindle assembly checkpoint (SAC), aneuploidy, and lethal chromosome segregation errors. We demonstrate that cell lethality from this segregation defect could be partially remedied by reinforcing bipolar attachment. In contrast, cells with the mec1-1 sml1-1 mutations suffer from severely impaired replication resumption upon removal of hydroxyurea. mec1-1 sml1-1 cells can, however, duplicate at least some of their centromeres and achieve bipolar attachment, leading to abortive segregation and fragmentation of incompletely replicated chromosomes. Our results highlight the importance of replicating yeast centromeres early and reveal different mechanisms of cell death due to differences in replication fork progression.

  3. The aba mutant of Arabidopsis thaliana is impaired in epoxy-carotenoid biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rock, C.D.; Zeevaart, J.A.D. (Michigan State Univ., East Lansing (United States))

    1991-09-01

    The three mutant alleles of the ABA locus of Arabidopsis thaliana result in plants that are deficient in the plant growth regulator abscisic acid (ABA). The authors have used {sup 18}O{sub 2} to label ABA in water-stressed leaves of mutant and wild-type Arabidopsis. Analysis by selected ion monitoring and tandem mass spectrometry of ({sup 18}O)ABA and its catabolites, phaseic acid and ABA-glucose ester ({beta}-D-glucopyranosyl abscisate), indicates that the aba genotypes are impaired in ABA biosynthesis and have a small ABA precursor pool of compounds that contain oxygens on the rings, presumably oxygenated carotenoids (xanthophylls). Quantitation of the carotenoids form mutant and wild-type leaves establishes that the aba alleles cause a deficiency of the epoxy-carotenoids violaxanthin and neoxanthin and an accumulation of their biosynthetic precursor, zeaxanthin. These results provide evidence that ABA is synthesized by oxidative cleavage of epoxy-carotenoids (the indirect pathway). Furthermore the carotenoid mutant they describe undergoes normal greening. Thus the aba alleles provide an opportunity to study the physiological roles of epoxy-carotenoids in photosynthesis in a higher plants.

  4. Specific TP53 Mutants Overrepresented in Ovarian Cancer Impact CNV, TP53 Activity, Responses to Nutlin-3a, and Cell Survival

    Directory of Open Access Journals (Sweden)

    Lisa K. Mullany

    2015-10-01

    Full Text Available Evolutionary Action analyses of The Cancer Gene Atlas data sets show that many specific p53 missense and gain-of-function mutations are selectively overrepresented and functional in high-grade serous ovarian cancer (HGSC. As homozygous alleles, p53 mutants are differentially associated with specific loss of heterozygosity (R273; chromosome 17; copy number variation (R175H; chromosome 9; and up-stream, cancer-related regulatory pathways. The expression of immune-related cytokines was selectively related to p53 status, showing for the first time that specific p53 mutants impact, and are related to, the immune subtype of ovarian cancer. Although the majority (31% of HGSCs exhibit loss of heterozygosity, a significant number (24% maintain a wild-type (WT allele and represent another HGSC subtype that is not well defined. Using human and mouse cell lines, we show that specific p53 mutants differentially alter endogenous WT p53 activity; target gene expression; and responses to nutlin-3a, a small molecular that activates WT p53 leading to apoptosis, providing “proof of principle” that ovarian cancer cells expressing WT and mutant alleles represent a distinct ovarian cancer subtype. We also show that siRNA knock down of endogenous p53 in cells expressing homozygous mutant alleles causes apoptosis, whereas cells expressing WT p53 (or are heterozygous for WT and mutant p53 alleles are highly resistant. Therefore, despite different gene regulatory pathways associated with specific p53 mutants, silencing mutant p53 might be a suitable, powerful, global strategy for blocking ovarian cancer growth in those tumors that rely on mutant p53 functions for survival. Knowing p53 mutational status in HGSC should permit new strategies tailored to control this disease.

  5. The Swedish mutant barley collection

    International Nuclear Information System (INIS)

    1989-01-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  6. The Swedish mutant barley collection

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-07-01

    Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

  7. Null alleles and sequence variations at primer binding sites of STR loci within multiplex typing systems.

    Science.gov (United States)

    Yao, Yining; Yang, Qinrui; Shao, Chengchen; Liu, Baonian; Zhou, Yuxiang; Xu, Hongmei; Zhou, Yueqin; Tang, Qiqun; Xie, Jianhui

    2018-01-01

    Rare variants are widely observed in human genome and sequence variations at primer binding sites might impair the process of PCR amplification resulting in dropouts of alleles, named as null alleles. In this study, 5 cases from routine paternity testing using PowerPlex ® 21 System for STR genotyping were considered to harbor null alleles at TH01, FGA, D5S818, D8S1179, and D16S539, respectively. The dropout of alleles was confirmed by using alternative commercial kits AGCU Expressmarker 22 PCR amplification kit and AmpFℓSTR ® . Identifiler ® Plus Kit, and sequencing results revealed a single base variation at the primer binding site of each STR locus. Results from the collection of previous reports show that null alleles at D5S818 were frequently observed in population detected by two PowerPlex ® typing systems and null alleles at D19S433 were mostly observed in Japanese population detected by two AmpFℓSTR™ typing systems. Furthermore, the most popular mutation type appeared the transition from C to T with G to A, which might have a potential relationship with DNA methylation. Altogether, these results can provide helpful information in forensic practice to the elimination of genotyping discrepancy and the development of primer sets. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. A sorghum (Sorghum bicolor mutant with altered carbon isotope ratio.

    Directory of Open Access Journals (Sweden)

    Govinda Rizal

    Full Text Available Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium's efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor mutant with a low δ13C characteristic. A mutant (named Mut33 with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT. The back-cross (BC1F1 progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used

  9. Circulation of Pneumocystis dihydropteroate synthase mutants in France.

    Science.gov (United States)

    Le Gal, Solène; Damiani, Céline; Perrot, Maëla; Rouillé, Amélie; Virmaux, Michèle; Quinio, Dorothée; Moalic, Elodie; Saliou, Philippe; Berthou, Christian; Le Meur, Yann; Totet, Anne; Nevez, Gilles

    2012-10-01

    Data on the prevalence of Pneumocystis jirovecii (P. jirovecii) dihydropteroate synthase (DHPS) mutants in France are still limited. In this study, mutant prevalence in the Brest region (western France) was determined. Archival pulmonary specimens from 85 patients infected with P. jirovecii and admitted to our institution (University Hospital, Brest) from October 2007 to February 2010 were retrospectively typed at the DHPS locus using a polymerase chain reaction-restriction fragment length polymorphism assay. Type identification was successful in 66 of 85 patients. Sixty-four patients were infected with a wild type, whereas mutants were found in 2 patients (2/66, 3%). Medical chart analysis revealed that these 2 patients usually lived in Paris. Another patient usually lived on the French Riviera, whereas 63 patients were from the city of Brest. Thus, the corrected prevalence of mutants in patients who effectively lived in our geographic area was 0% (0/63). Taking into account that i) Paris is characterized by a high prevalence of mutants from 18.5% to 40%, ii) infection diagnoses were performed in the 2 Parisians during their vacation Paris to Brest through infected vacationers. The study shows that the usual city of patient residence, rather than the city of infection diagnosis, is a predictor of mutants and that P. jirovecii infections involving mutants do not represent a public health issue in western France. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Absence-like and tonic seizures in aspartoacylase/attractin double-mutant mice.

    Science.gov (United States)

    Gohma, Hiroshi; Kuramoto, Takashi; Matalon, Reuben; Surendran, Sankar; Tyring, Stephen; Kitada, Kazuhiro; Sasa, Masashi; Serikawa, Tadao

    2007-04-01

    The Spontaneously Epileptic Rat (SER), a double-mutant for tremor and zitter mutations, shows spontaneous occurrences of absence-like and tonic seizures. Several lines of evidence suggest that the combined effect of Aspa and Atrn mutations is the most likely cause of the epileptic phenotype of the SER. To address this issue, we produced a new double-mutant mouse line carrying both homozygous Aspa-knockout and Atrn(mg-3J) mutant alleles. The Aspa/Atrn double-mutant mice exhibited absence-like and tonic seizures that were characterized by the appearance of 5-7 Hz spike-wave-like complexes and low voltage fast waves on EEGs. These results demonstrate directly that the simultaneous loss of the Aspa and Atrn gene functions causes epileptic seizures in the mouse and suggest that both Aspa and Atrn deficiencies might be responsible for epileptic seizures in the SER.

  11. Exploring new alleles for frost tolerance in winter rye.

    Science.gov (United States)

    Erath, Wiltrud; Bauer, Eva; Fowler, D Brian; Gordillo, Andres; Korzun, Viktor; Ponomareva, Mira; Schmidt, Malthe; Schmiedchen, Brigitta; Wilde, Peer; Schön, Chris-Carolin

    2017-10-01

    Rye genetic resources provide a valuable source of new alleles for the improvement of frost tolerance in rye breeding programs. Frost tolerance is a must-have trait for winter cereal production in northern and continental cropping areas. Genetic resources should harbor promising alleles for the improvement of frost tolerance of winter rye elite lines. For frost tolerance breeding, the identification of quantitative trait loci (QTL) and the choice of optimum genome-based selection methods are essential. We identified genomic regions involved in frost tolerance of winter rye by QTL mapping in a biparental population derived from a highly frost tolerant selection from the Canadian cultivar Puma and the European elite line Lo157. Lines per se and their testcrosses were phenotyped in a controlled freeze test and in multi-location field trials in Russia and Canada. Three QTL on chromosomes 4R, 5R, and 7R were consistently detected across environments. The QTL on 5R is congruent with the genomic region harboring the Frost resistance locus 2 (Fr-2) in Triticeae. The Puma allele at the Fr-R2 locus was found to significantly increase frost tolerance. A comparison of predictive ability obtained from the QTL-based model with different whole-genome prediction models revealed that besides a few large, also small QTL effects contribute to the genomic variance of frost tolerance in rye. Genomic prediction models assigning a high weight to the Fr-R2 locus allow increasing the selection intensity for frost tolerance by genome-based pre-selection of promising candidates.

  12. Multivariate analysis for selecting apple mutants

    International Nuclear Information System (INIS)

    Faedi, W.; Bagnara, G.L.; Rosati, P.; Cecchini, M.

    1992-01-01

    The mutlivariate analysis of four year records on several vegetative and productive traits of twenty-one apple mutants (3 of 'Jonathan', 3 of 'Ozark Gold', 14 of 'Mollie's Delicious', 1 of 'Neipling's Early Stayman)' induced by gamma radiations showed that observation of some traits of one-year-old shoots is the most efficient way to reveal compact growing apple mutants. In particular, basal cross-section area, total length and leaf area resulted the most appropriate parameters, while internode length together with conopy height and width are less appropriate. The most interesting mutants we found are: one of 'Mollie's Delicious for the best balance among tree and fruit traits and for high skin color; one of 'Neipling's Early Stayman' with an earlier and more extensively red colored apple than the original clone. (author)

  13. Fine mapping of dominant X-linked incompatibility alleles in Drosophila hybrids.

    Science.gov (United States)

    Matute, Daniel R; Gavin-Smyth, Jackie

    2014-04-01

    Sex chromosomes have a large effect on reproductive isolation and play an important role in hybrid inviability. In Drosophila hybrids, X-linked genes have pronounced deleterious effects on fitness in male hybrids, which have only one X chromosome. Several studies have succeeded at locating and identifying recessive X-linked alleles involved in hybrid inviability. Nonetheless, the density of dominant X-linked alleles involved in interspecific hybrid viability remains largely unknown. In this report, we study the effects of a panel of small fragments of the D. melanogaster X-chromosome carried on the D. melanogaster Y-chromosome in three kinds of hybrid males: D. melanogaster/D. santomea, D. melanogaster/D. simulans and D. melanogaster/D. mauritiana. D. santomea and D. melanogaster diverged over 10 million years ago, while D. simulans (and D. mauritiana) diverged from D. melanogaster over 3 million years ago. We find that the X-chromosome from D. melanogaster carries dominant alleles that are lethal in mel/san, mel/sim, and mel/mau hybrids, and more of these alleles are revealed in the most divergent cross. We then compare these effects on hybrid viability with two D. melanogaster intraspecific crosses. Unlike the interspecific crosses, we found no X-linked alleles that cause lethality in intraspecific crosses. Our results reveal the existence of dominant alleles on the X-chromosome of D. melanogaster which cause lethality in three different interspecific hybrids. These alleles only cause inviability in hybrid males, yet have little effect in hybrid females. This suggests that X-linked elements that cause hybrid inviability in males might not do so in hybrid females due to differing sex chromosome interactions.

  14. Mutants of alfalfa mosaic virus

    International Nuclear Information System (INIS)

    Roosien, J.

    1983-01-01

    In this thesis the isolation and characterization of a number of mutants of alfalfa mosaic virus, a plant virus with a coat protein dependent genome, is described. Thermo-sensitive (ts) mutants were selected since, at least theoretically, ts mutations can be present in all virus coded functions. It was found that a high percentage of spontaneous mutants, isolated because of their aberrant symptoms, were ts. The majority of these isolates could grow at the non-permissive temperature in the presence of a single wild type (wt) component. To increase the mutation rate virus preparations were treated with several mutagens. After nitrous acid treatment or irradiation with ultraviolet light, an increase in the level of mutations was observed. UV irradiation was preferred since it did not require large amounts of purified viral components. During the preliminary characterization of potential ts mutants the author also obtained one structural and several symptom mutants which were analysed further (chapter 7, 8 and 9). The properties of the ts mutants are described in chapter 3-7. (Auth.)

  15. Root hair mutants of barley

    International Nuclear Information System (INIS)

    Engvild, K.C.; Rasmussen, K.

    2005-01-01

    Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

  16. Frequency of CCR5Δ32 allele in healthy Bosniak population.

    Directory of Open Access Journals (Sweden)

    Grażyna Adler

    2014-08-01

    Full Text Available Recent evidence has demonstrated the role of CCR5Δ32 in a variety of human diseases: from infectious and inflammatory diseases to cancer. Several studies have confirmed that genetic variants in chemokine receptor CCR5 gene are correlated with susceptibility and resistance to HIV infection. A 32-nucleotide deletion within the CCR5 reading frame is associated with decreased susceptibility to HIV acquisition and a slower progression to AIDS. Mean frequency of CCR5Δ32 allele in Europe is approximately 10%. The highest allele frequency is observed among Nordic populations (about 12% and lower in the regions of Southeast Mediterranean (about 5%. Although the frequency of CCR5Δ32 was determined in numerous European populations, there is a lack of studies on this variant in the Bosnia and Hercegovina population. Therefore, the aim of our study was to assess the frequency of CCR5Δ32 allele in the cohort of Bosniaks and compare the results with European reports. CCR5Δ32 was detected by sequence-specific PCR in a sample of 100 healthy subjects from Bosnia and Herzegovina (DNA collected 2011-2013.  Mean age of the cohort being 58.8 (±10.7 years, with 82% of women. We identified 17 heterozygotes and one mutant homozygote in study group, with mean ∆32 allele frequency of 9.5%. CCR5∆32 allele frequency among Bosniaks is comparable to that found in Caucasian populations and follows the pattern of the north-southern gradient observed for Europe. Further studies on larger cohorts with adequate female-to-male ratio are necessary. 

  17. Availability of Micro-Tom mutant library combined with TILLING in molecular breeding of tomato fruit shelf-life.

    Science.gov (United States)

    Okabe, Yoshihiro; Asamizu, Erika; Ariizumi, Tohru; Shirasawa, Kenta; Tabata, Satoshi; Ezura, Hiroshi

    2012-06-01

    Novel mutant alleles of an ethylene receptor Solanum lycopersicum ETHYLENE RESPONSE1 (SlETR1) gene, Sletr1-1 and Sletr1-2, were isolated from the Micro-Tom mutant library by TILLING in our previous study. They displayed different levels of impaired fruit ripening phenotype, suggesting that these alleles could be a valuable breeding material for improving shelf life of tomato fruit. To conduct practical use of the Sletr1 alleles in tomato breeding, genetic complementation analysis by transformation of genes carrying each allele is required. In this study, we generated and characterized transgenic lines over-expressing Sletr1-1 and Sletr1-2. All transgenic lines displayed ethylene insensitive phenotype and ripening inhibition, indicating that Sletr1-1 and Sletr1-2 associate with the ethylene insensitive phenotype. The level of ethylene sensitivity in the seedling was different between Sletr1-1 and Sletr1-2 transgenic lines, whereas no apparent difference was observed in fruit ripening phenotype. These results suggested that it is difficult to fine-tune the extent of ripening by transgenic approach even if the weaker allele (Sletr1-2) was used. Our present and previous studies indicate that the Micro-Tom mutant library combined with TILLING could be an efficient tool for exploring genetic variations of important agronomic traits in tomato breeding.

  18. Availability of Micro-Tom mutant library combined with TILLING in molecular breeding of tomato fruit shelf-life

    Science.gov (United States)

    Okabe, Yoshihiro; Asamizu, Erika; Ariizumi, Tohru; Shirasawa, Kenta; Tabata, Satoshi; Ezura, Hiroshi

    2012-01-01

    Novel mutant alleles of an ethylene receptor Solanum lycopersicum ETHYLENE RESPONSE1 (SlETR1) gene, Sletr1-1 and Sletr1-2, were isolated from the Micro-Tom mutant library by TILLING in our previous study. They displayed different levels of impaired fruit ripening phenotype, suggesting that these alleles could be a valuable breeding material for improving shelf life of tomato fruit. To conduct practical use of the Sletr1 alleles in tomato breeding, genetic complementation analysis by transformation of genes carrying each allele is required. In this study, we generated and characterized transgenic lines over-expressing Sletr1-1 and Sletr1-2. All transgenic lines displayed ethylene insensitive phenotype and ripening inhibition, indicating that Sletr1-1 and Sletr1-2 associate with the ethylene insensitive phenotype. The level of ethylene sensitivity in the seedling was different between Sletr1-1 and Sletr1-2 transgenic lines, whereas no apparent difference was observed in fruit ripening phenotype. These results suggested that it is difficult to fine-tune the extent of ripening by transgenic approach even if the weaker allele (Sletr1-2) was used. Our present and previous studies indicate that the Micro-Tom mutant library combined with TILLING could be an efficient tool for exploring genetic variations of important agronomic traits in tomato breeding. PMID:23136532

  19. Determination of allele frequencies in nine short tandem repeat loci ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    Apr 17, 2008 ... the normal cellular process of replication of DNA molecules. ... probability of a certain genetic variant (alleles) occuring in ... have preservatives that hinder spoilage and are easily packaged .... Allele distribution at Nine STR.

  20. A new electrophoresis technique to separate microsatellite alleles ...

    African Journals Online (AJOL)

    A new electrophoresis technique to separate microsatellite alleles* ... African Journal of Biotechnology ... with the CEQTM 8000 Genetic Analysis System and ABI 3130xl DNA Sequencer easily separated products and determined allelic size, ...

  1. Allele specific expression and methylation in the bumblebee, Bombus terrestris

    Directory of Open Access Journals (Sweden)

    Zoë Lonsdale

    2017-09-01

    Full Text Available The social hymenoptera are emerging as models for epigenetics. DNA methylation, the addition of a methyl group, is a common epigenetic marker. In mammals and flowering plants methylation affects allele specific expression. There is contradictory evidence for the role of methylation on allele specific expression in social insects. The aim of this paper is to investigate allele specific expression and monoallelic methylation in the bumblebee, Bombus terrestris. We found nineteen genes that were both monoallelically methylated and monoallelically expressed in a single bee. Fourteen of these genes express the hypermethylated allele, while the other five express the hypomethylated allele. We also searched for allele specific expression in twenty-nine published RNA-seq libraries. We found 555 loci with allele-specific expression. We discuss our results with reference to the functional role of methylation in gene expression in insects and in the as yet unquantified role of genetic cis effects in insect allele specific methylation and expression.

  2. Comparative frequency and allelic distribution of ABO and Rh (D ...

    African Journals Online (AJOL)

    Gourab Dewan

    2015-02-18

    Feb 18, 2015 ... desh and having borders with India and Myanmar (Fig. 1). It is a hilly area with ..... calculated allelic frequencies for ABO/Rh systems previously. Therefore, allelic .... in backward caste population of Uttar Pradesh, India. Not Sci.

  3. Association mapping and favourable QTL alleles for fibre quality ...

    Indian Academy of Sciences (India)

    Cheng-Guang Dong

    A total of 201 markers were polymorphic and generated 394 allele loci, and 403 ... identified as containing favourable allele loci related to fibre quality traits. The identified .... environment. Field management followed respective local practices.

  4. Normal and mutant HTT interact to affect clinical severity and progression in Huntington disease

    DEFF Research Database (Denmark)

    Aziz, N A; Jurgens, C K; Landwehrmeyer, G B

    2009-01-01

    OBJECTIVE: Huntington disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion in the HD gene (HTT). We aimed to assess whether interaction between CAG repeat sizes in the mutant and normal allele could affect disease severity and progression. METHODS: Using...... with less severe symptoms and pathology. CONCLUSIONS: Increasing CAG repeat size in normal HTT diminishes the association between mutant CAG repeat size and disease severity and progression in Huntington disease. The underlying mechanism may involve interaction of the polyglutamine domains of normal...

  5. Mutants induced in winter rye (Secale cereale L.): Short straw-mutant No. 2714 and late-senescence mutant

    Energy Technology Data Exchange (ETDEWEB)

    Muszynski, S; Darlewska, M [Department of Plant Breeding and Seed Science, Warsaw Agricultural University, Warsaw (Poland)

    1990-01-01

    Full text: Mutants were induced by treating dormant seeds with ionizing radiation (fast neutrons) or chemicals (N-nitroso-N-ethyl urea or sodium azide). Among several mutants obtained, of special value is the short-straw mutant No. 2714 and a late senescent mutant. (author)

  6. Tuberculosis vaccine strain Mycobacterium bovis BCG Russia is a natural recA mutant

    Directory of Open Access Journals (Sweden)

    Böttger Erik C

    2008-07-01

    Full Text Available Abstract Background The current tuberculosis vaccine is a live vaccine derived from Mycobacterium bovis and attenuated by serial in vitro passaging. All vaccine substrains in use stem from one source, strain Bacille Calmette-Guérin. However, they differ in regions of genomic deletions, antigen expression levels, immunogenicity, and protective efficacy. Results As a RecA phenotype increases genetic stability and may contribute restricting the ongoing evolution of the various BCG substrains while maintaining their protective efficacy, we aimed to inactivate recA by allelic replacement in BCG vaccine strains representing different phylogenetic lineages (Pasteur, Frappier, Denmark, Russia. Homologous gene replacement was achieved successfully in three out of four strains. However, only illegitimate recombination was observed in BCG substrain Russia. Sequence analyses of recA revealed that a single nucleotide insertion in the 5' part of recA led to a translational frameshift with an early stop codon making BCG Russia a natural recA mutant. At the protein level BCG Russia failed to express RecA. Conclusion According to phylogenetic analyses BCG Russia is an ancient vaccine strain most closely related to the parental M. bovis. We hypothesize that recA inactivation in BCG Russia occurred early and is in part responsible for its high degree of genomic stability, resulting in a substrain that has less genetic alterations than other vaccine substrains with respect to M. bovis AF2122/97 wild-type.

  7. Allele and genotype frequencies of -β lactoglobulin gene in Iranian ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-04

    Aug 4, 2009 ... Blood samples were supplied from 80 Najdi cattle and 80 buffalo from different cities of Khouzestan province. ... The allele B of β-Lactoglobulin occurred at a higher frequency than the allele A in both. Najdi cattle and buffalo. .... that of the B allele in both groups of animals studied. Expected heterozygosity ...

  8. Directional Positive Selection on an Allele of Arbitrary Dominance

    OpenAIRE

    Teshima, Kosuke M.; Przeworski, Molly

    2006-01-01

    Most models of positive directional selection assume codominance of the beneficial allele. We examine the importance of this assumption by implementing a coalescent model of positive directional selection with arbitrary dominance. We find that, for a given mean fixation time, a beneficial allele has a much weaker effect on diversity at linked neutral sites when the allele is recessive.

  9. Production and characterization of radiation-sensitive meiotic mutants of Coprinus cinereus

    International Nuclear Information System (INIS)

    Zolan, M.E.; Tremel, C.J.; Pukkila, P.J.

    1988-01-01

    We have isolated four gamma-sensitive mutants of the basidiomycete Coprinus cinereus. When homozygous, two of these (rad 3-1 and rad 9-1) produce fruiting bodies with very few viable basidiospores, the products of meiosis in this organism. A less radiation-sensitive allele of RAD 3, rad 3-2, causes no apparent meiotic defect in homozygous strains. Quantitative measurements of oidial survival of rad 3-1;rad 9-1 double mutants compared to the single mutants indicated that rad 3-1 and rad 9-1 mutants are defective in the same DNA repair pathway. In the pew viable basidiospores that are produced by these two strains, essentially normal levels of meiotic recombination can be detected. None of the mutants exhibits increased sensitivity to UV radiation. Cytological examination of meiotic chromosomes from mutant and wild-type fruiting bodies showed that rad 3-1 homozygous strains fail to condense and pair homologous chromosomes during prophase I. Although rad 9-1 strains are successful at chromosome pairing, meiosis is usually not completed in these mutants

  10. Studies on induced partially resistant mutants of barley against powdery mildew

    International Nuclear Information System (INIS)

    Roebbelen, G.; Abdel-Hafez, A.G.; Reinhold, M.; Kwon, H.J.; Neuhaus-Steinmetz, J.P.; Heun, M.

    1983-01-01

    After mutagenic seed treatment of three partially resistant cultivars of spring barley with EMS and NaN 3 , 45 mutants in a first and 16 in a second experiment were selected in the M 2 -M 4 generations. The screening was done alternatively under natural infection in the field or controlled infection with a single pathotype in the greenhouse. These mutants exhibited a higher resistance and a higher susceptibility, respectively, than the initial cultivars Asse, Bomi and Vada. Some mutants expressed their altered resistance behaviour particularly during certain stages of development. High-level resistance was conditioned by mutation in the ml-o locus in three cases. For several Bomi mutants pathotype specificity with and without reversed ranking was proven as well as pathotype non-specificity in comparison with the reaction of the original cultivar. In 14 cases studied the inheritance of the involved mutants was monogenic recessive. The laevigatum locus responsible for the intermediate mildew resistance of Bomi was not affected by the mutations. Detection of groups of allelic mutants showed that there are at least two regions in the barley genome in which mutations for mildew resistance can occur rather frequently. In total, the past ten years of this mutation research have given convincing evidence that the strategies of mutant screening applied have yielded promising new material both for breeding and for progress in basic understanding of host-pathogen interactions. (author)

  11. Isolation and characterization of xylitol-assimilating mutants of recombinant Saccharomyces cerevisiae.

    Science.gov (United States)

    Tani, Tatsunori; Taguchi, Hisataka; Fujimori, Kazuhiro E; Sahara, Takehiko; Ohgiya, Satoru; Kamagata, Yoichi; Akamatsu, Takashi

    2016-10-01

    To clarify the mechanisms of xylitol utilization, three xylitol-assimilating mutants were isolated from recombinant Saccharomyces cerevisiae strains showing highly efficient xylose-utilization. The nucleotide sequences of the mutant genomes were analyzed and compared with those of the wild-type strains and the mutation sites were identified. gal80 mutations were common to all the mutants, and recessive to the wild-type allele. Hence we constructed a gal80Δ mutant and confirmed that the gal80Δ mutant showed a xylitol-assimilation phenotype. When the constructed gal80Δ mutant was crossed with the three isolated mutants, all diploid hybrids showed xylitol assimilation, indicating that the mutations were all located in the GAL80. We analyzed the role of the galactose permease Gal2, controlled by the regulatory protein Gal80, in assimilating xylitol. A gal2Δ gal80Δ double mutant did not show xylitol assimilation, whereas expression of GAL2 under the control of the TDH3 promoter in the GAL80 strain did result in assimilation. These data indicate that Gal2 was needed for xylitol assimilation in the wild-type strain. When the gal80 mutant with an initial cell concentration of A660 = 20 was used for batch fermentation in a complex medium containing 20 g/L xylose or 20 g/L xylitol at pH 5.0 and 30°C under oxygen limitation, the gal80 mutant consumed 100% of the xylose within 12 h, but xylitol within 100 h, indicating that xylose reductase is required for xylitol consumption in oxygen-limited conditions. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Isolation of new gravitropic mutants under hypergravity conditions

    Directory of Open Access Journals (Sweden)

    Akiko Mori

    2016-09-01

    Full Text Available Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upwards. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes. In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using Next-Generation Sequencing (NGS and Single Nucleotide Polymorphism (SNP-based markers. Using the endodermal-amyloplast less 1 (eal1 mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1 mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis.

  13. Isolation of New Gravitropic Mutants under Hypergravity Conditions.

    Science.gov (United States)

    Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

    2016-01-01

    Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

  14. Two alleles of the AtCesA3 gene in Arabidopsis thaliana display intragenic complementation.

    Science.gov (United States)

    Pysh, Leonard D

    2015-09-01

    Cellulose is the most abundant biomolecule on the planet, yet the mechanism by which it is synthesized by higher plants remains largely unknown. In Arabidopsis thaliana (L.) Heynh, synthesis of cellulose in the primary cell wall requires three different cellulose synthase genes (AtCesA1, AtCesA3, and AtCesA6-related genes [AtCesA2, AtCesA5, and AtCesA6]). The multiple response expansion1 (mre1) mutant contains a hypomorphic AtCesA3 allele that results in significantly shorter, expanded roots. Crosses between mre1 and another allele of AtCesA3 (constitutive expression of VSP1, cev1) yielded an F1 with roots considerably longer and thinner than either parent, suggesting intragenic complementation. The F2 generation resulting from self-crossing these F1 showed three different root phenotypes: roots like mre1, roots like cev1, and roots like the F1. The segregation patterns of the three root phenotypes in multiple F2 and F3 generations were determined. Multiple characteristics of the roots and shoots were analyzed both qualitatively and quantitatively at different developmental stages, both on plates and on soil. The trans-heterozygous plants differed significantly from the parental mre1 and cev1 lines. The two alleles display intragenic complementation. A classic genetic interpretation of these results would suggest that cellulose synthesis requires homo-multimerization of cellulose synthase monomers. © 2015 Botanical Society of America.

  15. Allelic Variation of Cytochrome P450s Drives Resistance to Bednet Insecticides in a Major Malaria Vector.

    Science.gov (United States)

    Ibrahim, Sulaiman S; Riveron, Jacob M; Bibby, Jaclyn; Irving, Helen; Yunta, Cristina; Paine, Mark J I; Wondji, Charles S

    2015-10-01

    Scale up of Long Lasting Insecticide Nets (LLINs) has massively contributed to reduce malaria mortality across Africa. However, resistance to pyrethroid insecticides in malaria vectors threatens its continued effectiveness. Deciphering the detailed molecular basis of such resistance and designing diagnostic tools is critical to implement suitable resistance management strategies. Here, we demonstrated that allelic variation in two cytochrome P450 genes is the most important driver of pyrethroid resistance in the major African malaria vector Anopheles funestus and detected key mutations controlling this resistance. An Africa-wide polymorphism analysis of the duplicated genes CYP6P9a and CYP6P9b revealed that both genes are directionally selected with alleles segregating according to resistance phenotypes. Modelling and docking simulations predicted that resistant alleles were better metabolizers of pyrethroids than susceptible alleles. Metabolism assays performed with recombinant enzymes of various alleles confirmed that alleles from resistant mosquitoes had significantly higher activities toward pyrethroids. Additionally, transgenic expression in Drosophila showed that flies expressing resistant alleles of both genes were significantly more resistant to pyrethroids compared with those expressing the susceptible alleles, indicating that allelic variation is the key resistance mechanism. Furthermore, site-directed mutagenesis and functional analyses demonstrated that three amino acid changes (Val109Ile, Asp335Glu and Asn384Ser) from the resistant allele of CYP6P9b were key pyrethroid resistance mutations inducing high metabolic efficiency. The detection of these first DNA markers of metabolic resistance to pyrethroids allows the design of DNA-based diagnostic tools to detect and track resistance associated with bednets scale up, which will improve the design of evidence-based resistance management strategies.

  16. Deducing the pathogenic contribution of recessive ABCA4 alleles in an outbred population.

    Science.gov (United States)

    Schindler, Emily I; Nylen, Erik L; Ko, Audrey C; Affatigato, Louisa M; Heggen, Andrew C; Wang, Kai; Sheffield, Val C; Stone, Edwin M

    2010-10-01

    Accurate prediction of the pathogenic effects of specific genotypes is important for the design and execution of clinical trials as well as for meaningful counseling of individual patients. However, for many autosomal recessive diseases, it can be difficult to deduce the relative pathogenic contribution of individual alleles because relatively few affected individuals share the same two disease-causing variations. In this study, we used multiple regression analysis to estimate the pathogenicity of specific alleles of ABCA4 in patients with retinal phenotypes ranging from Stargardt disease to retinitis pigmentosa. This analysis revealed quantitative allelic effects on two aspects of the visual phenotype, visual acuity (P disease and will also aid in the optimal selection of subjects for clinical trials of new therapies.

  17. Suspension Array for Multiplex Detection of Eight Fungicide-Resistance Related Alleles in Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2016-09-01

    Full Text Available A simple and high-throughput assay to detect fungicide resistance is required for large-scale monitoring of the emergence of resistant strains of Botrytis cinerea. Using suspension array technology performed on a Bio-Plex 200 System, we developed a single-tube allele-specific primer extension (ASPE assay that can simultaneously detect eight alleles in one reaction. These eight alleles include E198 and 198A of the β-Tubulin gene (BenA, H272 and 272Y of the Succinate dehydrogenase iron–sulfur subunit gene (SdhB, I365 and 365S of the putative osmosensor histidine kinase gene (BcOS1, and F412 and 412S of the 3-ketoreductase gene (erg27. This assay was first established and optimized with eight plasmid templates containing the DNA sequence variants BenA-E198, BenA-198A, SdhB-H272, SdhB-272Y, BcOS1-I365, BcOS1-365S, erg27-F412, and erg27-412S. Results indicated that none of the probes showed cross-reactivity with one another. The minimum limit of detection for these genotypes was one copy per test. Four mutant plasmids were mixed with 10 ng/μL wild-type genomic DNA in different ratios. Detection sensitivity of mutant loci was 0.45% for BenA-E198A, BcOS1-I365S, and erg27-F412S, and was 4.5% for SdhB-H272Y. A minimum quantity of 0.1 ng of genomic DNA was necessary to obtain reliable results. This is the first reported assay that can simultaneously detect mutations in BenA, SdhB, BcOS1, and erg27.

  18. Suspension Array for Multiplex Detection of Eight Fungicide-Resistance Related Alleles in Botrytis cinerea.

    Science.gov (United States)

    Zhang, Xin; Xie, Fei; Lv, Baobei; Zhao, Pengxiang; Ma, Xuemei

    2016-01-01

    A simple and high-throughput assay to detect fungicide resistance is required for large-scale monitoring of the emergence of resistant strains of Botrytis cinerea . Using suspension array technology performed on a Bio-Plex 200 System, we developed a single-tube allele-specific primer extension assay that can simultaneously detect eight alleles in one reaction. These eight alleles include E198 and 198A of the β-Tubulin gene ( BenA ), H272 and 272Y of the Succinate dehydrogenase iron-sulfur subunit gene ( SdhB) , I365 and 365S of the putative osmosensor histidine kinase gene ( BcOS1 ), and F412 and 412S of the 3-ketoreductase gene ( erg27 ). This assay was first established and optimized with eight plasmid templates containing the DNA sequence variants BenA- E198, BenA- 198A, SdhB- H272, SdhB- 272Y, BcOS1- I365, BcOS1- 365S, erg27 -F412, and erg27 -412S. Results indicated that none of the probes showed cross-reactivity with one another. The minimum limit of detection for these genotypes was one copy per test. Four mutant plasmids were mixed with 10 ng/μL wild-type genomic DNA in different ratios. Detection sensitivity of mutant loci was 0.45% for BenA- E198A, BcOS1- I365S, and erg27 -F412S, and was 4.5% for SdhB- H272Y. A minimum quantity of 0.1 ng of genomic DNA was necessary to obtain reliable results. This is the first reported assay that can simultaneously detect mutations in BenA , SdhB , BcOS1 , and erg27 .

  19. Characterization of reduced height mutant of emmer wheat var. NP200 (Triticum dicoccum)

    International Nuclear Information System (INIS)

    Suman, Sud; Nayeem, K.A.; Bhagwat, S.G.

    2006-01-01

    Full text: Emmer wheat commonly known as Khapli is cultivated on limited area in Tamil Nadu, Andhra Pradesh, Karnataka, Maharashtra and Gujarat. Although cultivation of emmer wheat is confirmed to a small area, improvement work in this species is gaining importance because of its potential for diabetic patients and high dietary fibre in comparison to durum and bread wheats. Emmer wheat cultivar NP200 is a selection from local wheats of Andhra Pradesh. The cultivar NP200 is tall and is prone to lodging leading to yield loss. Therefore, systematic effort to improve cultivar NP200 is needed with the objective to reduce height and introduce lodging tolerance and to improve harvest index. The cultivar NP200 was irradiated with γ-rays. A reduced height mutant with vigorous growth and high tillering was found in M2 population. The mutant was designated as HW1095. The progeny of mutant in M3 showed 35.7 percent reduction in height as compared to parent. The HW1095 mutant was subjected to gibberellic acid treatment at seedling stage and was found to be insensitive to gibberellic acid. An allele specific marker for major dwarfing gene Rht B1b was used to check the status of dwarfing gene in semi dwarf emmer (DDK1009, DDK1025, HW5013, HW5301 and MACS2961) and tall emmer (Np200 and NP201), semi dwarf durums (HD4502, HD4530, MACS2846) along with dwarf mutant (HW1095). The validity of primer in semi dwarf durums and emmer for Rht B 1b gene was found to be perfect. The parent variety NP200 showed presence of wild type allele (Rht B1a) with the primer pair BF-WR1. All semi dwarf emmer showed a band of 237 bp with primer pair BF-MR1. However, mutant (HW1095) showed absence of amplification for both Rht B1a and Rht B1b alleles with respective primer pairs. The results indicated that the reduced height mutant carried a mutation different than from the existing allele (Rht B1b)

  20. Self-incompatibility of Prunus tenella and evidence that reproductively isolated species of Prunus have different SFB alleles coupled with an identical S-RNase allele.

    Science.gov (United States)

    Surbanovski, Nada; Tobutt, Kenneth R; Konstantinović, Miroslav; Maksimović, Vesna; Sargent, Daniel J; Stevanović, Vladimir; Bosković, Radovan I

    2007-05-01

    Many species of Prunus display an S-RNase-based gametophytic self-incompatibility (SI), controlled by a single highly polymorphic multigene complex termed the S-locus. This comprises tightly linked stylar- and pollen-expressed genes that determine the specificity of the SI response. We investigated SI of Prunus tenella, a wild species found in small, isolated populations on the Balkan peninsula, initially by pollination experiments and identifying stylar-expressed RNase alleles. Nine P. tenella S-RNase alleles (S(1)-S(9)) were cloned; their sequence analysis showed a very high ratio of non-synonymous to synonymous nucleotide substitutions (K(a)/K(s)) and revealed that S-RNase alleles of P. tenella, unlike those of Prunus dulcis, show positive selection in all regions except the conserved regions and that between C2 and RHV. Remarkably, S(8)-RNase, was found to be identical to S(1)-RNase from Prunus avium, a species that does not interbreed with P. tenella and, except for just one amino acid, to S(11) of P. dulcis. However, the corresponding introns and S-RNase-SFB intergenic regions showed considerable differences. Moreover, protein sequences of the pollen-expressed SFB alleles were not identical, harbouring 12 amino-acid replacements between those of P. tenella SFB(8) and P. avium SFB(1). Implications of this finding for hypotheses about the evolution of new S-specificities are discussed.

  1. DQB1*06:02 allele-specific expression varies by allelic dosage, not narcolepsy status

    DEFF Research Database (Denmark)

    Weiner Lachmi, Karin; Lin, Ling; Kornum, Birgitte Rahbek

    2012-01-01

    The association of narcolepsy-cataplexy, a sleep disorder caused by the loss of hypocretin/orexin neurons in the hypothalamus, with DQA1*01:02-DQB1*06:02 is one of the tightest known single-allele human leukocyte antigen (HLA) associations. In this study, we explored genome-wide expression...

  2. Validation of the digital PCR system in tyrosine kinase inhibitor-resistant EGFR mutant non-small-cell lung cancer.

    Science.gov (United States)

    Masago, Katsuhiro; Fujita, Shiro; Hata, Akito; Okuda, Chiyuki; Yoshizumi, Yuko; Kaji, Reiko; Katakami, Nobuyuki; Hirata, Yukio; Yatabe, Yasushi

    2018-03-01

    The aim of this study was to compare the accuracy of the QuantStudio 3D Digital polymerase chain reaction (dPCR) system and a PCR-based next generation sequencing (NGS) system for detecting a secondary mutation in the epidermal growth factor receptor (EGFR) gene T790M in non-small cell lung cancer (NSCLC) patients previously diagnosed with EGFR-activating mutations. Twenty-five patients with NSCLC previously treated with EGFR-TKIs were examined. The patients were treated daily with either erlotinib or gefitinib. New biopsies, followed by DNA sequencing on an Ion Torrent systems using the Ion Torrent AmpliSeq Cancer Hotspot Panel and dPCR were performed. A comparison of NGS, sensitive PCR, and dPCR revealed that the sensitivities of NGS and dPCR were similar in this study. As well, T790M was detected in as low as about 5% of mutant allelic frequencies, which represented 5% of the total reads on site mapped reads in NGS and greater than 5% of the dPCR reads, which represented mutant and wild type copies. The strategy in which NGS sequencing is followed by revealed acquired mutation with dPCR may be a reasonable one. We demonstrated the utility of combining NGS and dPCR as a tool for monitoring T790M. NGS and dPCR with formalin-fixed paraffin-embedded (FFPE) specimens might become a standard genomic test for exploring acquired resistance to targeted molecular medicines. © 2018 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.

  3. Identification, genealogical structure and population genetics of S-alleles in Malus sieversii, the wild ancestor of domesticated apple.

    Science.gov (United States)

    Ma, X; Cai, Z; Liu, W; Ge, S; Tang, L

    2017-09-01

    The self-incompatibility (SI) gene that is specifically expressed in pistils encodes the SI-associated ribonuclease (S-RNase), functioning as the female-specificity determinant of a gametophytic SI system. Despite extensive surveys in Malus domestica, the S-alleles have not been fully investigated for Malus sieversii, the primary wild ancestor of the domesticated apple. Here we screened the M. sieversii S-alleles via PCR amplification and sequencing, and identified 14 distinct alleles in this species. By contrast, nearly 40 are present in its close wild relative, Malus sylvestris. We further sequenced 8 nuclear genes to provide a neutral reference, and investigated the evolution of S-alleles via genealogical and population genetic analyses. Both shared ancestral polymorphism and an excess of non-synonymous substitution were detected in the S-RNases of the tribe Maleae in Rosaceae, indicating the action of long-term balancing selection. Approximate Bayesian Computations based on the reference neutral loci revealed a severe bottleneck in four of the six studied M. sieversii populations, suggesting that the low number of S-alleles found in this species is mainly the result of diversity loss due to a drastic population contraction. Such a bottleneck may lead to ambiguous footprints of ongoing balancing selection detected at the S-locus. This study not only elucidates the constituents and number of S-alleles in M. sieversii but also illustrates the potential utility of S-allele number shifts in demographic inference for self-incompatible plant species.

  4. Spectrum of Phenylalanine Hydroxylase Gene Mutations in Hamadan and Lorestan Provinces of Iran and Their Associations with Variable Number of Tandem Repeat Alleles

    Directory of Open Access Journals (Sweden)

    Reza Alibakhshi

    2018-05-01

    Full Text Available Phenylketonuria (PKU is one of the most common known inherited metabolic diseases. The present study aimed to investigate the status of molecular defects in phenylalanine hydroxylase (PAH gene in western Iranian PKU patients (predominantly from Kermanshah, Hamadan, and Lorestan provinces during 2014-2016. Additionally, the results were compared with similar studies in Iran. Nucleotide sequence analysis of all 13 exons and their flanking intronic regions of the PAH gene was performed in 18 western Iranian PKU patients. Moreover, a variable number of tandem repeat (VNTR located in the PAH gene was studied. The results revealed a mutational spectrum encompassing 11 distinct mutations distributed along the PAH gene sequence on 34 of the 36 mutant alleles (diagnostic efficiency of 94.4%. Also, four PAH VNTR alleles (with repeats of 3, 7, 8 and 9 were detected. The three most frequent mutations were IVS9+5G>A, IVS7-5T>C, and p.P281L with the frequency of 27.8%, 11%, and 11%, respectively. The results showed that there is not only a consanguineous relation, but also a difference in PAH characters of mutations between Kermanshah and the other two parts of western Iran (Hamadan and Lorestan. Also, it seems that the spectrum of mutations in western Iran is relatively distinct from other parts of the country, suggesting that this region might be a special PAH gene distribution region. Moreover, our findings can be useful in the identification of genotype to phenotype relationship in patients, and provide future abilities for confirmatory diagnostic testing, prognosis, and predict the severity of PKU patients.

  5. Spectrum of Phenylalanine Hydroxylase Gene Mutations in Hamadan and Lorestan Provinces of Iran and Their Associations with Variable Number of Tandem Repeat Alleles.

    Science.gov (United States)

    Alibakhshi, Reza; Moradi, Keivan; Biglari, Mostafa; Shafieenia, Samaneh

    2018-05-01

    Phenylketonuria (PKU) is one of the most common known inherited metabolic diseases. The present study aimed to investigate the status of molecular defects in phenylalanine hydroxylase ( PAH ) gene in western Iranian PKU patients (predominantly from Kermanshah, Hamadan, and Lorestan provinces) during 2014-2016. Additionally, the results were compared with similar studies in Iran. Nucleotide sequence analysis of all 13 exons and their flanking intronic regions of the PAH gene was performed in 18 western Iranian PKU patients. Moreover, a variable number of tandem repeat (VNTR) located in the PAH gene was studied. The results revealed a mutational spectrum encompassing 11 distinct mutations distributed along the PAH gene sequence on 34 of the 36 mutant alleles (diagnostic efficiency of 94.4%). Also, four PAH VNTR alleles (with repeats of 3, 7, 8 and 9) were detected. The three most frequent mutations were IVS9+5G>A, IVS7-5T>C, and p.P281L with the frequency of 27.8%, 11%, and 11%, respectively. The results showed that there is not only a consanguineous relation, but also a difference in PAH characters of mutations between Kermanshah and the other two parts of western Iran (Hamadan and Lorestan). Also, it seems that the spectrum of mutations in western Iran is relatively distinct from other parts of the country, suggesting that this region might be a special PAH gene distribution region. Moreover, our findings can be useful in the identification of genotype to phenotype relationship in patients, and provide future abilities for confirmatory diagnostic testing, prognosis, and predict the severity of PKU patients.

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

    Science.gov (United States)

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

    2018-04-01

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

  7. Detection of MPL mutations by a novel allele-specific PCR-based strategy.

    Science.gov (United States)

    Furtado, Larissa V; Weigelin, Helmut C; Elenitoba-Johnson, Kojo S J; Betz, Bryan L

    2013-11-01

    MPL mutation testing is recommended in patients with suspected primary myelofibrosis or essential thrombocythemia who lack the JAK2 V617F mutation. MPL mutations can occur at allelic levels below 15%, which may escape detection by commonly used mutation screening methods such as Sanger sequencing. We developed a novel multiplexed allele-specific PCR assay capable of detecting most recurrent MPL exon 10 mutations associated with primary myelofibrosis and essential thrombocythemia (W515L, W515K, W515A, and S505N) down to a sensitivity of 2.5% mutant allele. Test results were reviewed from 15 reference cases and 1380 consecutive specimens referred to our laboratory for testing. Assay performance was compared to Sanger sequencing across a series of 58 specimens with MPL mutations. Positive cases consisted of 45 with W515L, 6 with S505N, 5 with W515K, 1 with W515A, and 1 with both W515L and S505N. Seven cases had mutations below 5% that were undetected by Sanger sequencing. Ten additional cases had mutation levels between 5% and 15% that were not consistently detected by sequencing. All results were easily interpreted in the allele-specific test. This assay offers a sensitive and reliable solution for MPL mutation testing. Sanger sequencing appears insufficiently sensitive for robust MPL mutation detection. Our data also suggest the relative frequency of S505N mutations may be underestimated, highlighting the necessity for inclusion of this mutation in MPL test platforms. Copyright © 2013 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  8. Identical substitutions in magnesium chelatase paralogs result in chlorophyll deficient soybean mutants

    Science.gov (United States)

    The soybean (Glycine max (L.) Merr.) chlorophyll deficient line MinnGold is a spontaneous mutant characterized by yellow foliage. Map-based cloning and transgenic complementation revealed that the mutant phenotype is caused by a non-synonymous nucleotide substitution in the third exon of a Mg-chelat...

  9. Severity of mutant phenotype in a series of chlorophyll-deficient wheat mutants depends on light intensity and the severity of the block in chlorophyll synthesis.

    Science.gov (United States)

    Falbel, T G; Meehl, J B; Staehelin, L A

    1996-10-01

    Analyses of a series of allelic chlorina mutants of wheat (Triticum aestivum L.), which have partial blocks in chlorophyll (Chl) synthesis and, therefore, a limited Chl supply, reinforce the principle that Chl is required for the stable accumulation of Chl-binding proteins and that only reaction centers accumulate when the supply of Chl is severely limited. Depending on the rate of Chl accumulation (determined by the severity of the mutation) and on the rate of turnover of Chl and its precursors (determined by the environment in which the plant is grown), the mutants each reach an equilibrium of Chl synthesis and degradation. Together these mutants generate a spectrum of phenotypes. Under the harshest conditions (high illumination), plants with moderate blocks in Chl synthesis have membranes with very little Chl and Chl-proteins and membrane stacks resembling the thylakoids of the lethal xantha mutants of barely grown at low to medium light intensities (which have more severe blocks). In contrast, when grown under low-light conditions the same plants with moderate blocks have thylakoids resembling those of the wild type. The wide range of phenotypes of Chl b-deficient mutants has historically produced more confusion than enlightenment, but incomparable growth conditions can now explain the discrepancies reported in the literature.

  10. Studies on leaf mutants of Pea. (Part) I. Morphology, performance and somatic chromosomes

    International Nuclear Information System (INIS)

    Kaul, M.L.H.; Anjali, A.

    1988-01-01

    Three recessive non-allelic mutant genes alter foliar morphology of pea when present singly and in combination. Gene acacia replaces tendrils by a terminal leaflet, afila replaces leaflets by tendrils and cochleata replaces stipules by spoon shaped appendages. In combination, these genes drastically alter leaf morphology; plants can be identified only after flowering. The mutant genes influence shoot height, floral organ number, maturity period, grain yield and seed protein production; inter- and intra-genotypic variability in certain metric traits is significant. Influence of cochleata gene over floral form and function is considerable. In terms of seed yield and protein content, breeding value of all the mutants except of acacia is low because these mutant genes represent foreign untuned genes in pea genome. Segregation deficit is maximum in triple gene mutant with highly impaired fertility and low seed production. Somatic chromosome number in all the mutants and recombinants is 14; in morphology the chromosomes do not differ from the initial line, Bonneville. (author). 9 refs., 4 tabs

  11. Decreased uv mutagenesis in cdc8, a DNA replication mutant of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Prakash, L.; Hinkle, D.; Prakash, S.

    1978-01-01

    A DNA replication mutant of yeast, cdc8, was found to decrease uv-induced reversion of lys2-1, arg4-17, tryl and ural. This effect was observed with all three alleles of cdc8 tested. Survival curves obtained following uv irradiation in cdc8 rad double mutants show that cdc8 is epistatic to rad6, as well as to rad1; cdc8 rad51 double mutants seem to be more sensitive than the single mutants. Since uv-induced reversion in cdc8 rad1 and cdc8 rad51 double mutants is like that of the cdc8 single mutants, we conclude that CDC8 plays a direct role in error-prone repair. To test whether CDC8 codes for a DNA polymerase, we have purified both DNA polymerase I and DNA polymerase II from cdc8 and CDC+ cells. The purified DNA polymerases from cdc8 were no more heat labile than those from CDC+, suggesting that CDC8 is not a structural gene for either enzyme

  12. Mutant TDP-43 within motor neurons drives disease onset but not progression in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Ditsworth, Dara; Maldonado, Marcus; McAlonis-Downes, Melissa; Sun, Shuying; Seelman, Amanda; Drenner, Kevin; Arnold, Eveline; Ling, Shuo-Chien; Pizzo, Donald; Ravits, John; Cleveland, Don W; Da Cruz, Sandrine

    2017-06-01

    Mutations in TDP-43 cause amyotrophic lateral sclerosis (ALS), a fatal paralytic disease characterized by degeneration and premature death of motor neurons. The contribution of mutant TDP-43-mediated damage within motor neurons was evaluated using mice expressing a conditional allele of an ALS-causing TDP-43 mutant (Q331K) whose broad expression throughout the central nervous system mimics endogenous TDP-43. TDP-43 Q331K mice develop age- and mutant-dependent motor deficits from degeneration and death of motor neurons. Cre-recombinase-mediated excision of the TDP-43 Q331K gene from motor neurons is shown to delay onset of motor symptoms and appearance of TDP-43-mediated aberrant nuclear morphology, and abrogate subsequent death of motor neurons. However, reduction of mutant TDP-43 selectively in motor neurons did not prevent age-dependent degeneration of axons and neuromuscular junction loss, nor did it attenuate astrogliosis or microgliosis. Thus, disease mechanism is non-cell autonomous with mutant TDP-43 expressed in motor neurons determining disease onset but progression defined by mutant acting within other cell types.

  13. Differential effects of lesion mimic mutants in barley on disease development by facultative pathogens

    Science.gov (United States)

    McGrann, Graham R. D.; Steed, , Andrew; Burt, Christopher; Nicholson, Paul; Brown, James K. M.

    2015-01-01

    Lesion mimic mutants display spontaneous necrotic spots and chlorotic leaves as a result of mis-regulated cell death programmes. Typically these mutants have increased resistance to biotrophic pathogens but their response to facultative fungi that cause necrotrophic diseases is less well studied. The effect of altered cell death regulation on the development of disease caused by Ramularia collo-cygni, Fusarium culmorum and Oculimacula yallundae was explored using a collection of barley necrotic (nec) lesion mimic mutants. nec8 mutants displayed lower levels of all three diseases compared to nec9 mutants, which had increased R. collo-cygni but decreased F. culmorum disease symptoms. nec1 mutants reduced disease development caused by both R. collo-cygni and F. culmorum. The severity of the nec1-induced lesion mimic phenotype and F. culmorum symptom development was reduced by mutation of the negative cell death regulator MLO. The significant reduction in R. collo-cygni symptoms caused by nec1 was completely abolished in the presence of the mlo-5 allele and both symptoms and fungal biomass were greater than in the wild-type. These results indicate that physiological pathways involved in regulation of cell death interact with one another in their effects on different fungal pathogens. PMID:25873675

  14. A modified screening system for loss-of-function and dominant negative alleles of essential MCMV genes.

    Directory of Open Access Journals (Sweden)

    Madlen Pogoda

    Full Text Available Inactivation of gene products by dominant negative mutants is a valuable tool to assign functions to yet uncharacterized proteins, to map protein-protein interactions or to dissect physiological pathways. Detailed functional and structural knowledge about the target protein would allow the construction of inhibitory mutants by targeted mutagenesis. Yet, such data are limited for the majority of viral proteins, so that the target gene needs to be subjected to random mutagenesis to identify suitable mutants. However, for cytomegaloviruses this requires a two-step screening approach, which is time-consuming and labor-intensive. Here, we report the establishment of a high-throughput suitable screening system for the identification of inhibitory alleles of essential genes of the murine cytomegalovirus (MCMV. In this screen, the site-specific recombination of a specifically modified MCMV genome was transferred from the bacterial background to permissive host cells, thereby combining the genetic engineering and the rescue test in one step. Using a reference set of characterized pM53 mutants it was shown that the novel system is applicable to identify non-complementing as well as inhibitory mutants in a high-throughput suitable setup. The new cis-complementation assay was also applied to a basic genetic characterization of pM99, which was identified as essential for MCMV growth. We believe that the here described novel genetic screening approach can be adapted for the genetic characterization of essential genes of any large DNA viruses.

  15. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  16. Flightless mutants in the melon fly and oriental fruit fly (Diptera: Tephritidae) and their possible role in the sterile insect release method

    International Nuclear Information System (INIS)

    McCombs, S.D.; Saul, S.H.

    1992-01-01

    Two new mutants that affect adult wing morphology and render the flies incapable of flight.sbd.bubble wing (bw) in the melon fly, Bactrocera cucurbitae (Coquillett), and small wing (sw) in the oriental fruit fly, Bactrocera dorsalis (Hendel).sbd.are described. Both mutants have variable expression and are caused by autosomal, recessive genes. We discuss the possible role of these alleles in constructing genetic sex sorting systems to improve the effectiveness and efficiency of the sterile insect release method

  17. Nicotiana plumbaginifolia hlg mutants have a mutation in a PHYB-type phytochrome gene: they have elongated hypocotyls in red light, but are not elongated as adult plants.

    Science.gov (United States)

    Hudson, M; Robson, P R; Kraepiel, Y; Caboche, M; Smith, H

    1997-11-01

    Two new allelic mutants of Nicotiana plumbaginifolia have been isolated which display a hypocotyl which is long (hlg) when seedlings are grown in continuous white light (W). This can be accounted for by the decreased response to red light (R) of the hypocotyl elongation rate in these mutants. Responses to other wavelengths are unaffected in the mutants. When grown in white light, mature hlg mutants are not elongated with respect to the wild-type; they also bolt and flower later. The shade-avoidance responses to red/far red ratio (R:FR) are intact in these mutants. Both mutants are deficient in phyB-like polypeptide that is immunodetectable in the wild-type; both have wild-type levels of a phyA-like polypeptide. These alleles are inherited in a partially dominant manner, and correspond to single-base missense mutations in a gene highly homologous to N. tabacum PHYB, which codes for a phytochrome B-type photoreceptor. One allele, hlg-1, has an introduced amino acid substitution; this may define a residue essential for phytochrome protein stability. The other allele, hlg-2, has a stop codon introduced C-terminal to the chromophore binding domain. As these phyB mutants are unaffected in shade-avoidance responses, but deficient in perception of R, it is concluded that the phyB absent in these mutants is responsible for R perception in the N. plumbaginifolia seedling, but is not a R:FR sensor in light-grown plants.

  18. Deletion mutant defines DQ beta variants with DR4 positive DQw3 positive haplotypes

    International Nuclear Information System (INIS)

    Nepom, B.S.; Kim, S.J.; Nepom, G.T.

    1986-01-01

    We describe the production of an HLA deletion mutation by radiation mutagenesis of a DR4- and DQw3-homozygous, Dw4- and Dw14-heterozygous cell line designed to analyze polymorphisms associated with DR4 and DQw3. Southern blot analysis confirms a deletion of class I and class II genes on one haplotype. Variation in DQ beta alleles associated with DQw3 was previously described by characteristic RFLP patterns for a DQ beta bene. One pattern, which correlated precisely with A-10-83 monoclonal antibody reactivity (TA10), defined an allele which we call DQ''3.1''. The mutant cell line has lost the polymorphic bands on Southern blots corresponding to the DQ''3.1'' allele, while the intact Dw14 haplotype retains the alternate allele at DQ beta which is DQw-3 positive. TA10-negative. These data demonstrate the segregation of two DQw3 positive DQ beta allelic variants, both associated with DR4, which can be distinguished on the basis of both RFLP and monoclonal antibody reactivity

  19. Allele Frequency - JSNP | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available nd 39 SNPs are assayed in three (POP_*) and two (RIKEN_japanese_*) panels, respectively. Derived from Flat f... assay (JBIC-allele and RIKEN_japanese_*), TaqMan assay (RIKEN-allele) or direct sequencing / allelic discri...unteers under informed consent RIKEN_japanese_normal_weight - 711 unrelated japanese normal weight volunteer...s ( body mass index RIKEN_japanese_obese - 796 unrelated japanese obese patients

  20. Molecular elucidation of a new allelic variation at the Sg-5 gene associated with the absence of group A saponins in wild soybean.

    Science.gov (United States)

    Sundaramoorthy, Jagadeesh; Park, Gyu Tae; Mukaiyama, Kyosuke; Tsukamoto, Chigen; Chang, Jeong Ho; Lee, Jeong-Dong; Kim, Jeong Hoe; Seo, Hak Soo; Song, Jong Tae

    2018-01-01

    In soybean, triterpenoid saponin is one of the major secondary metabolites and is further classified into group A and DDMP saponins. Although they have known health benefits for humans and animals, acetylation of group A saponins causes bitterness and gives an astringent taste to soy products. Therefore, several studies are being conducted to eliminate acetylated group A saponins. Previous studies have isolated and characterized the Sg-5 (Glyma.15g243300) gene, which encodes the cytochrome P450 72A69 enzyme and is responsible for soyasapogenol A biosynthesis. In this study, we elucidated the molecular identity of a novel mutant of Glycine soja, 'CWS5095'. Phenotypic analysis using TLC and LC-PDA/MS/MS showed that the mutant 'CWS5095' did not produce any group A saponins. Segregation analysis showed that the absence of group A saponins is controlled by a single recessive allele. The locus was mapped on chromosome 15 (4.3 Mb) between Affx-89193969 and Affx-89134397 where the previously identified Glyma.15g243300 gene is positioned. Sequence analysis of the coding region for the Glyma.15g243300 gene revealed the presence of four SNPs in 'CWS5095' compared to the control lines. One of these four SNPs (G1127A) leads to the amino acid change Arg376Lys in the EXXR motif, which is invariably conserved among the CYP450 superfamily proteins. Co-segregation analysis showed that the missense mutation (Arg376Lys) was tightly linked with the absence of group A saponins in 'CWS5095'. Even though Arg and Lys have similar chemical features, the 3D modelled protein structure indicates that the replacement of Arg with Lys may cause a loss-of-function of the Sg-5 protein by inhibiting the stable binding of a heme cofactor to the CYP72A69 apoenzyme.

  1. Allelic hierarchy of CDH23 mutations causing non-syndromic deafness DFNB12 or Usher syndrome USH1D in compound heterozygotes.

    Science.gov (United States)

    Schultz, Julie M; Bhatti, Rashid; Madeo, Anne C; Turriff, Amy; Muskett, Julie A; Zalewski, Christopher K; King, Kelly A; Ahmed, Zubair M; Riazuddin, Saima; Ahmad, Nazir; Hussain, Zawar; Qasim, Muhammad; Kahn, Shaheen N; Meltzer, Meira R; Liu, Xue Z; Munisamy, Murali; Ghosh, Manju; Rehm, Heidi L; Tsilou, Ekaterini T; Griffith, Andrew J; Zein, Wadih M; Brewer, Carmen C; Riazuddin, Sheikh; Friedman, Thomas B

    2011-11-01

    Recessive mutant alleles of MYO7A, USH1C, CDH23, and PCDH15 cause non-syndromic deafness or type 1 Usher syndrome (USH1) characterised by deafness, vestibular areflexia, and vision loss due to retinitis pigmentosa. For CDH23, encoding cadherin 23, non-syndromic DFNB12 deafness is associated primarily with missense mutations hypothesised to have residual function. In contrast, homozygous nonsense, frame shift, splice site, and some missense mutations of CDH23, all of which are presumably functional null alleles, cause USH1D. The phenotype of a CDH23 compound heterozygote for a DFNB12 allele in trans configuration to an USH1D allele is not known and cannot be predicted from current understanding of cadherin 23 function in the retina and vestibular labyrinth. To address this issue, this study sought CDH23 compound heterozygotes by sequencing this gene in USH1 probands, and families segregating USH1D or DFNB12. Five non-syndromic deaf individuals were identified with normal retinal and vestibular phenotypes that segregate compound heterozygous mutations of CDH23, where one mutation is a known or predicted USH1 allele. One DFNB12 allele in trans configuration to an USH1D allele of CDH23 preserves vision and balance in deaf individuals, indicating that the DFNB12 allele is phenotypically dominant to an USH1D allele. This finding has implications for genetic counselling and the development of therapies for retinitis pigmentosa in Usher syndrome. ACCESSION NUMBERS: The cDNA and protein Genbank accession numbers for CDH23 and cadherin 23 used in this paper are AY010111.2 and AAG27034.2, respectively.

  2. Characterization of new allele influencing flowering time in bread wheat introgressed from Triticum militinae.

    Science.gov (United States)

    Ivaničová, Zuzana; Jakobson, Irena; Reis, Diana; Šafář, Jan; Milec, Zbyněk; Abrouk, Michael; Doležel, Jaroslav; Järve, Kadri; Valárik, Miroslav

    2016-09-25

    Flowering time variation was identified within a mapping population of doubled haploid lines developed from a cross between the introgressive line 8.1 and spring bread wheat cv. Tähti. The line 8.1 carried introgressions from tetraploid Triticum militinae in the cv. Tähti genetic background on chromosomes 1A, 2A, 4A, 5A, 7A, 1B and 5B. The most significant QTL for the flowering time variation was identified within the introgressed region on chromosome 5A and its largest effect was associated with the VRN-A1 locus, accounting for up to 70% of phenotypic variance. The allele of T. militinae origin was designated as VRN-A1f-like. The effect of the VRN-A1f-like allele was verified in two other mapping populations. QTL analysis identified that in cv. Tähti and cv. Mooni genetic background, VRN-A1f-like allele incurred a delay of 1.9-18.6 days in flowering time, depending on growing conditions. Sequence comparison of the VRN-A1f-like and VRN-A1a alleles from the parental lines of the mapping populations revealed major mutations in the promoter region as well as in the first intron, including insertion of a MITE element and a large deletion. The sequence variation allowed construction of specific diagnostic PCR markers for VRN-A1f-like allele determination. Identification and quantification of the effect of the VRN-A1f-like allele offers a useful tool for wheat breeding and for studying fine-scale regulation of flowering pathways in wheat. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Recombinational micro-evolution of functionally different metallothionein promoter alleles from Orchesella cincta

    Directory of Open Access Journals (Sweden)

    van Straalen Nico M

    2007-06-01

    Full Text Available Abstract Background Metallothionein (mt transcription is elevated in heavy metal tolerant field populations of Orchesella cincta (Collembola. This suggests that natural selection acts on transcriptional regulation of mt in springtails at sites where cadmium (Cd levels in soil reach toxic values This study investigates the nature and the evolutionary origin of polymorphisms in the metallothionein promoter (pmt and their functional significance for mt expression. Results We sequenced approximately 1600 bp upstream the mt coding region by genome walking. Nine pmt alleles were discovered in NW-European populations. They differ in the number of some indels, consensus transcription factor binding sites and core promoter elements. Extensive recombination events between some of the alleles can be inferred from the alignment. A deviation from neutral expectations was detected in a cadmium tolerant population, pointing towards balancing selection on some promoter stretches. Luciferase constructs were made from the most abundant alleles, and responses to Cd, paraquat (oxidative stress inducer and moulting hormone were studied in cell lines. By using paraquat we were able to dissect the effect of oxidative stress from the Cd specific effect, and extensive differences in mt induction levels between these two stressors were observed. Conclusion The pmt alleles evolved by a number of recombination events, and exhibited differential inducibilities by Cd, paraquat and molting hormone. In a tolerant population from a metal contaminated site, promoter allele frequencies differed significantly from a reference site and nucleotide polymorphisms in some promoter stretches deviated from neutral expectations, revealing a signature of balancing selection. Our results suggest that the structural differences in the Orchesella cincta metallothionein promoter alleles contribute to the metallothionein -over-expresser phenotype in cadmium tolerant populations.

  4. Database for the ampC alleles in Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Nabil Karah

    Full Text Available Acinetobacter baumannii is a troublesome opportunistic pathogen with a high capacity for clonal dissemination. We announce the establishment of a database for the ampC locus in A. baumannii, in which novel ampC alleles are differentiated based on the occurrence of ≥ 1 nucleotide change, regardless of whether it is silent or missense. The database is openly accessible at the pubmlst platform for A. baumannii (http://pubmlst.org/abaumannii/. Forty-eight distinctive alleles of the ampC locus have so far been identified and deposited in the database. Isolates from clonal complex 1 (CC1, according to the Pasteur multilocus sequence typing scheme, had a variety of the ampC locus alleles, including alleles 1, 3, 4, 5, 6, 7, 8, 13, 14, 17, and 18. On the other hand, isolates from CC2 had the ampC alleles 2, 3, 19, 20, 21, 22, 23, 24, 26, 27, 28, and 46. Allele 3 was characteristic for sequence types ST3 or ST32. The ampC alleles 10, 16, and 25 were characteristic for CC10, ST16, and CC25, respectively. Our study points out that novel gene databases, in which alleles are numbered based on differences in their nucleotide identities, should replace traditional records that use amino acid substitutions to define new alleles.

  5. Allele-specific expression at the androgen receptor alpha gene in a hybrid unisexual fish, the Amazon molly (Poecilia formosa.

    Directory of Open Access Journals (Sweden)

    Fangjun Zhu

    Full Text Available The all-female Amazon molly (Poecilia formosa is the result of a hybridization of the Atlantic molly (P. mexicana and the sailfin molly (P. latipinna approximately 120,000 years ago. As a gynogenetic species, P. formosa needs to copulate with heterospecific males including males from one of its bisexual ancestral species. However, the sperm only triggers embryogenesis of the diploid eggs. The genetic information of the sperm donor typically will not contribute to the next generation of P. formosa. Hence, P. formosa possesses generally one allele from each of its ancestral species at any genetic locus. This raises the question whether both ancestral alleles are equally expressed in P. formosa. Allele-specific expression (ASE has been previously assessed in various organisms, e.g., human and fish, and ASE was found to be important in the context of phenotypic variability and disease. In this study, we utilized Real-Time PCR techniques to estimate ASE of the androgen receptor alpha (arα gene in several distinct tissues of Amazon mollies. We found an allelic bias favoring the maternal ancestor (P. mexicana allele in ovarian tissue. This allelic bias was not observed in the gill or the brain tissue. Sequencing of the promoter regions of both alleles revealed an association between an Indel in a known CpG island and differential expression. Future studies may reveal whether our observed cis-regulatory divergence is caused by an ovary-specific trans-regulatory element, preferentially activating the allele of the maternal ancestor.

  6. Mutant genes in pea breeding

    International Nuclear Information System (INIS)

    Swiecicki, W.K.

    1990-01-01

    Full text: Mutations of genes Dpo (dehiscing pods) and A (anthocyanin synthesis) played a role in pea domestication. A number of other genes were important in cultivar development for 3 types of usage (dry seeds, green vegetable types, fodder), e.g. fn, fna, le, p, v, fas and af. New genes (induced and spontaneous), are important for present ideotypes and are registered by the Pisum Genetics Association (PGA). Comparison of a pea variety ideotype with the variation available in gene banks shows that breeders need 'new' features. In mutation induction experiments, genotype, mutagen and method of treatment (e.g. combined or fractionated doses) are varied for broadening the mutation spectrum and selecting more genes of agronomic value. New genes are genetically analysed. In Poland, some mutant varieties with the gene afila were registered, controlling lodging by a shorter stem and a higher number of internodes. Really non-lodging pea varieties could strongly increase seed yield. But the probability of detecting a major gene for lodging resistance is low. Therefore, mutant genes with smaller influence on plant architecture are sought, to combine their effect by crossing. Promising seem to be the genes rogue, reductus and arthritic as well as a number of mutant genes not yet genetically identified. The gene det for terminal inflorescence - similarly to Vicia faba - changes plant development. Utilisation of assimilates and ripening should be better. Improvement of harvest index should give higher seed yield. A number of genes controlling disease resistance are well known (eg. Fw, Fnw, En, mo and sbm). Important in mass screening of resistance are closely linked gene markers. Pea gene banks collect respective lines, but mutants induced in highly productive cultivars would be better. Inducing gene markers sometimes seems to be easier than transfer by crossing. Mutation induction in pea breeding is probably more important because a high number of monogenic features are

  7. Pollen irradiation method to obtain mutants in cucumber

    International Nuclear Information System (INIS)

    Iida, S.; Amano, E.

    1988-01-01

    Seed irradiation for mutation induction in dioecious crops like cucumber is not very useful because chimerism of the mutated tissues makes the segregation of mutants in the M 2 generation nearly impossible. This problem does not exist with pollen irradiation. Cucumber (Cucumis sativus L. var. Nishikisuyo) was used for a model experiment. The petals of male and female flowers were closed by pinching with binding wire before flowering to prevent pollination by insects. On the flowering day, the male flowers were collected and irradiated with 1kR to 10 kR of acute gamma rays (137-Cs), then used to pollinate the female flowers. The M 1 seeds thus obtained are not chimeric but heterozygous for induced mutations. When planted, no mutant phenotype appeared. Selfing within a plant lead to segregation of mutants in the M 2 generation. Seedling examination revealed eight mutants. One mutant line, in which the shape of leaves changed from pentagonal to round heart shape, was found under field conditions. The optimal dose for pollen irradiation seems to be between 2 kR and 4kR

  8. An extra early mutant of pigeonpea

    International Nuclear Information System (INIS)

    Ravikesavan, R.; Kalaimagal, T.; Rathnaswamy, R.

    2001-01-01

    The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M 2 to M 4 generation. In the M 4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

  9. Problem-Solving Test: Tryptophan Operon Mutants

    Science.gov (United States)

    Szeberenyi, Jozsef

    2010-01-01

    This paper presents a problem-solving test that deals with the regulation of the "trp" operon of "Escherichia coli." Two mutants of this operon are described: in mutant A, the operator region of the operon carries a point mutation so that it is unable to carry out its function; mutant B expresses a "trp" repressor protein unable to bind…

  10. Multimer Formation Explains Allelic Suppression of PRDM9 Recombination Hotspots.

    Science.gov (United States)

    Baker, Christopher L; Petkova, Pavlina; Walker, Michael; Flachs, Petr; Mihola, Ondrej; Trachtulec, Zdenek; Petkov, Petko M; Paigen, Kenneth

    2015-09-01

    Genetic recombination during meiosis functions to increase genetic diversity, promotes elimination of deleterious alleles, and helps assure proper segregation of chromatids. Mammalian recombination events are concentrated at specialized sites, termed hotspots, whose locations are determined by PRDM9, a zinc finger DNA-binding histone methyltransferase. Prdm9 is highly polymorphic with most alleles activating their own set of hotspots. In populations exhibiting high frequencies of heterozygosity, questions remain about the influences different alleles have in heterozygous individuals where the two variant forms of PRDM9 typically do not activate equivalent populations of hotspots. We now find that, in addition to activating its own hotspots, the presence of one Prdm9 allele can modify the activity of hotspots activated by the other allele. PRDM9 function is also dosage sensitive; Prdm9+/- heterozygous null mice have reduced numbers and less active hotspots and increased numbers of aberrant germ cells. In mice carrying two Prdm9 alleles, there is allelic competition; the stronger Prdm9 allele can partially or entirely suppress chromatin modification and recombination at hotspots of the weaker allele. In cell cultures, PRDM9 protein variants form functional heteromeric complexes which can bind hotspots sequences. When a heteromeric complex binds at a hotspot of one PRDM9 variant, the other PRDM9 variant, which would otherwise not bind, can still methylate hotspot nucleosomes. We propose that in heterozygous individuals the underlying molecular mechanism of allelic suppression results from formation of PRDM9 heteromers, where the DNA binding activity of one protein variant dominantly directs recombination initiation towards its own hotspots, effectively titrating down recombination by the other protein variant. In natural populations with many heterozygous individuals, allelic competition will influence the recombination landscape.

  11. A novel mouse Fgfr2 mutant, hobbyhorse (hob, exhibits complete XY gonadal sex reversal.

    Directory of Open Access Journals (Sweden)

    Pam Siggers

    Full Text Available The secreted molecule fibroblast growth factor 9 (FGF9 plays a critical role in testis determination in the mouse. In embryonic gonadal somatic cells it is required for maintenance of SOX9 expression, a key determinant of Sertoli cell fate. Conditional gene targeting studies have identified FGFR2 as the main gonadal receptor for FGF9 during sex determination. However, such studies can be complicated by inefficient and variable deletion of floxed alleles, depending on the choice of Cre deleter strain. Here, we report a novel, constitutive allele of Fgfr2, hobbyhorse (hob, which was identified in an ENU-based forward genetic screen for novel testis-determining loci. Fgr2hob is caused by a C to T mutation in the invariant exon 7, resulting in a polypeptide with a mis-sense mutation at position 263 (Pro263Ser in the third extracellular immunoglobulin-like domain of FGFR2. Mutant homozygous embryos show severe limb and lung defects and, when on the sensitised C57BL/6J (B6 genetic background, undergo complete XY gonadal sex reversal associated with failure to maintain expression of Sox9. Genetic crosses employing a null mutant of Fgfr2 suggest that Fgr2hob is a hypomorphic allele, affecting both the FGFR2b and FGFR2c splice isoforms of the receptor. We exploited the consistent phenotype of this constitutive mutant by analysing MAPK signalling at the sex-determining stage of gonad development, but no significant abnormalities in mutant embryos were detected.

  12. Novel Hypomorphic Alleles of the Mouse Tyrosinase Gene Induced by CRISPR-Cas9 Nucleases Cause Non-Albino Pigmentation Phenotypes.

    Science.gov (United States)

    Challa, Anil K; Boitet, Evan R; Turner, Ashley N; Johnson, Larry W; Kennedy, Daniel; Downs, Ethan R; Hymel, Katherine M; Gross, Alecia K; Kesterson, Robert A

    2016-01-01

    Tyrosinase is a key enzyme in melanin biosynthesis. Mutations in the gene encoding tyrosinase (Tyr) cause oculocutaneous albinism (OCA1) in humans. Alleles of the Tyr gene have been useful in studying pigment biology and coat color formation. Over 100 different Tyr alleles have been reported in mice, of which ≈24% are spontaneous mutations, ≈60% are radiation-induced, and the remaining alleles were obtained by chemical mutagenesis and gene targeting. Therefore, most mutations were random and could not be predicted a priori. Using the CRISPR-Cas9 system, we targeted two distinct regions of exon 1 to induce pigmentation changes and used an in vivo visual phenotype along with heteroduplex mobility assays (HMA) as readouts of CRISPR-Cas9 activity. Most of the mutant alleles result in complete loss of tyrosinase activity leading to an albino phenotype. In this study, we describe two novel in-frame deletion alleles of Tyr, dhoosara (Sanskrit for gray) and chandana (Sanskrit for sandalwood). These alleles are hypomorphic and show lighter pigmentation phenotypes of the body and eyes. This study demonstrates the utility of CRISPR-Cas9 system in generating domain-specific in-frame deletions and helps gain further insights into structure-function of Tyr gene.

  13. Novel Hypomorphic Alleles of the Mouse Tyrosinase Gene Induced by CRISPR-Cas9 Nucleases Cause Non-Albino Pigmentation Phenotypes.

    Directory of Open Access Journals (Sweden)

    Anil K Challa

    Full Text Available Tyrosinase is a key enzyme in melanin biosynthesis. Mutations in the gene encoding tyrosinase (Tyr cause oculocutaneous albinism (OCA1 in humans. Alleles of the Tyr gene have been useful in studying pigment biology and coat color formation. Over 100 different Tyr alleles have been reported in mice, of which ≈24% are spontaneous mutations, ≈60% are radiation-induced, and the remaining alleles were obtained by chemical mutagenesis and gene targeting. Therefore, most mutations were random and could not be predicted a priori. Using the CRISPR-Cas9 system, we targeted two distinct regions of exon 1 to induce pigmentation changes and used an in vivo visual phenotype along with heteroduplex mobility assays (HMA as readouts of CRISPR-Cas9 activity. Most of the mutant alleles result in complete loss of tyrosinase activity leading to an albino phenotype. In this study, we describe two novel in-frame deletion alleles of Tyr, dhoosara (Sanskrit for gray and chandana (Sanskrit for sandalwood. These alleles are hypomorphic and show lighter pigmentation phenotypes of the body and eyes. This study demonstrates the utility of CRISPR-Cas9 system in generating domain-specific in-frame deletions and helps gain further insights into structure-function of Tyr gene.

  14. A de novo mosaic mutation in SPAST with two novel alternative alleles and chromosomal copy number variant in a boy with spastic paraplegia and autism spectrum disorder.

    Science.gov (United States)

    Matthews, A M; Tarailo-Graovac, M; Price, E M; Blydt-Hansen, I; Ghani, A; Drögemöller, B I; Robinson, W P; Ross, C J; Wasserman, W W; Siden, H; van Karnebeek, C D

    2017-10-01

    Here we report a 12 year old male with an extreme presentation of spastic paraplegia along with autism and dysmorphisms. Whole exome sequencing identified a predicted pathogenic pair of missense variants in SPAST at the same chromosomal location, each with a different alternative allele, while a chromosome microarray identified a 1.73 Mb paternally inherited copy gain of 1q21.1q21.2 resulting in a blended phenotype of both Spastic paraplegia 4 and 1q21.1 microduplication syndrome. We believe that the extreme phenotype observed is likely caused by the presence of cells which contain only mutant SPAST, but that the viability of the patient is possible due mosaicism of mutant alleles observed in different proportions across tissues. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Estimating and testing the effect of allelic recombination on the ...

    African Journals Online (AJOL)

    Jane

    2011-01-21

    Jan 21, 2011 ... The significance of the correlation coefficient as well as the fitted regression model was obtained using. Analysis of Variance method. Key words: Allele, genotype, regression, correlation, F-ratio, analysis of variance. INTRODUCTION .... while if the allelic replacement is being made on an Aa individual the ...

  16. Low Penetrance Alleles in Colorectal Cancer: the arachidonic acid pathway

    NARCIS (Netherlands)

    C.L.E. Siezen

    2006-01-01

    textabstractIn summary, we can conclude that we have successfully identified low penetrance alleles in the PPAR., PLA2G2A and ALOX15 genes, conferring differential colorectal adenoma risk, and two such alleles in the PTGS2 gene, one of which is also involved in colorectal cancer risk. These

  17. Comparison of bovine lymphocyte antigen DRB3.2 allele ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... The bovine lymphocyte antigen (BoLA-DRB3) gene encodes cell ... alleles were more resistant to clinical mastitis. ... DRB3.2 allele pattern in two Iranian Holstein cow .... observed and the number of immune parameters with.

  18. Evolutionary dynamics of sporophytic self-incompatibility alleles in plants

    DEFF Research Database (Denmark)

    Schierup, Mikkel Heide; Vekemans, Xavier; Christiansen, Freddy Bugge

    1997-01-01

    codominantly in both pollen and style (SSIcod), in the second, alleles form a dominance hierarchy in pollen and style (SSIdom). In the third model, alleles interact codominantly in the style and form a dominance hierarchy in the pollen (SSIdomcod). The SSIcod model behaves similarly to the model...

  19. Human minisatellite alleles detectable only after PCR amplification.

    Science.gov (United States)

    Armour, J A; Crosier, M; Jeffreys, A J

    1992-01-01

    We present evidence that a proportion of alleles at two human minisatellite loci is undetected by standard Southern blot hybridization. In each case the missing allele(s) can be identified after PCR amplification and correspond to tandem arrays too short to detect by hybridization. At one locus, there is only one undetected allele (population frequency 0.3), which contains just three repeat units. At the second locus, there are at least five undetected alleles (total population frequency 0.9) containing 60-120 repeats; they are not detected because these tandem repeats give very poor signals when used as a probe in standard Southern blot hybridization, and also cross-hybridize with other sequences in the genome. Under these circumstances only signals from the longest tandemly repeated alleles are detectable above the nonspecific background. The structures of these loci have been compared in human and primate DNA, and at one locus the short human allele containing three repeat units is shown to be an intermediate state in the expansion of a monomeric precursor allele in primates to high copy number in the longer human arrays. We discuss the implications of such loci for studies of human populations, minisatellite isolation by cloning, and the evolution of highly variable tandem arrays.

  20. Comparative frequency and allelic distribution of ABO and Rh (D ...

    African Journals Online (AJOL)

    Background: Allelic distribution of major blood groups (ABO and rhesus) has not been defined in Bangladeshi population. Determinants of blood group frequency in this region have not been studied properly. Aim: To determine ABO and rhesus blood group frequency and allelic distribution in a multiethnic area of ...

  1. Apolipoprotein E4 allele does not influence serum triglyceride ...

    African Journals Online (AJOL)

    This study investigated how the APOε4 allele affects the serum triglyceride response after a fatmeal in apparently healthy black South African young adults. Sixty students were successfully screened for APOE genotype using Restriction Fragment Length Polymorphism (RFLP) and were divided into four groups; the ε2 allele ...

  2. Assigning breed origin to alleles in crossbred animals.

    Science.gov (United States)

    Vandenplas, Jérémie; Calus, Mario P L; Sevillano, Claudia A; Windig, Jack J; Bastiaansen, John W M

    2016-08-22

    For some species, animal production systems are based on the use of crossbreeding to take advantage of the increased performance of crossbred compared to purebred animals. Effects of single nucleotide polymorphisms (SNPs) may differ between purebred and crossbred animals for several reasons: (1) differences in linkage disequilibrium between SNP alleles and a quantitative trait locus; (2) differences in genetic backgrounds (e.g., dominance and epistatic interactions); and (3) differences in environmental conditions, which result in genotype-by-environment interactions. Thus, SNP effects may be breed-specific, which has led to the development of genomic evaluations for crossbred performance that take such effects into account. However, to estimate breed-specific effects, it is necessary to know breed origin of alleles in crossbred animals. Therefore, our aim was to develop an approach for assigning breed origin to alleles of crossbred animals (termed BOA) without information on pedigree and to study its accuracy by considering various factors, including distance between breeds. The BOA approach consists of: (1) phasing genotypes of purebred and crossbred animals; (2) assigning breed origin to phased haplotypes; and (3) assigning breed origin to alleles of crossbred animals based on a library of assigned haplotypes, the breed composition of crossbred animals, and their SNP genotypes. The accuracy of allele assignments was determined for simulated datasets that include crosses between closely-related, distantly-related and unrelated breeds. Across these scenarios, the percentage of alleles of a crossbred animal that were correctly assigned to their breed origin was greater than 90 %, and increased with increasing distance between breeds, while the percentage of incorrectly assigned alleles was always less than 2 %. For the remaining alleles, i.e. 0 to 10 % of all alleles of a crossbred animal, breed origin could not be assigned. The BOA approach accurately assigns

  3. Complementation of the amylose-free starch mutant of potato (Solanum tuberosum.) by the gene encoding granule-bound starch synthase

    NARCIS (Netherlands)

    van der Leij, E.R.; Visser, R.G.E.; OOSTERHAVEN, K; VANDERKOP, DAM; Jacobsen, E.; Feenstra, W.

    1991-01-01

    Agrobacterium rhizogenes-mediated introduction of the wild-type allele of the gene encoding granule-bound starch synthase (GBSS) into the amylose-free starch mutant amf of potato leads to restoration of GBSS activity and amylose synthesis, which demonstrates that Amf is the structural gene for GBSS.

  4. A risk allele for nicotine dependence in CHRNA5 is a protective allele for cocaine dependence.

    Science.gov (United States)

    Grucza, Richard A; Wang, Jen C; Stitzel, Jerry A; Hinrichs, Anthony L; Saccone, Scott F; Saccone, Nancy L; Bucholz, Kathleen K; Cloninger, C Robert; Neuman, Rosalind J; Budde, John P; Fox, Louis; Bertelsen, Sarah; Kramer, John; Hesselbrock, Victor; Tischfield, Jay; Nurnberger, John I; Almasy, Laura; Porjesz, Bernice; Kuperman, Samuel; Schuckit, Marc A; Edenberg, Howard J; Rice, John P; Goate, Alison M; Bierut, Laura J

    2008-12-01

    A nonsynonymous coding polymorphism, rs16969968, of the CHRNA5 gene that encodes the alpha-5 subunit of the nicotinic acetylcholine receptor (nAChR) has been found to be associated with nicotine dependence. The goal of this study was to examine the association of this variant with cocaine dependence. Genetic association analysis was performed in two independent samples of unrelated case and control subjects: 1) 504 European Americans participating in the Family Study on Cocaine Dependence (FSCD) and 2) 814 European Americans participating in the Collaborative Study on the Genetics of Alcoholism (COGA). In the FSCD, there was a significant association between the CHRNA5 variant and cocaine dependence (odds ratio = .67 per allele, p = .0045, assuming an additive genetic model), but in the reverse direction compared with that previously observed for nicotine dependence. In multivariate analyses that controlled for the effects of nicotine dependence, both the protective effect for cocaine dependence and the previously documented risk effect for nicotine dependence were statistically significant. The protective effect for cocaine dependence was replicated in the COGA sample. In COGA, effect sizes for habitual smoking, a proxy phenotype for nicotine dependence, were consistent with those observed in FSCD. The minor (A) allele of rs16969968, relative to the major G allele, appears to be both a risk factor for nicotine dependence and a protective factor for cocaine dependence. The biological plausibility of such a bidirectional association stems from the involvement of nAChRs with both excitatory and inhibitory modulation of dopamine-mediated reward pathways.

  5. Tracking human migrations by the analysis of the distribution of HLA alleles, lineages and haplotypes in closed and open populations

    Science.gov (United States)

    Vina, Marcelo A. Fernandez; Hollenbach, Jill A.; Lyke, Kirsten E.; Sztein, Marcelo B.; Maiers, Martin; Klitz, William; Cano, Pedro; Mack, Steven; Single, Richard; Brautbar, Chaim; Israel, Shosahna; Raimondi, Eduardo; Khoriaty, Evelyne; Inati, Adlette; Andreani, Marco; Testi, Manuela; Moraes, Maria Elisa; Thomson, Glenys; Stastny, Peter; Cao, Kai

    2012-01-01

    The human leucocyte antigen (HLA) system shows extensive variation in the number and function of loci and the number of alleles present at any one locus. Allele distribution has been analysed in many populations through the course of several decades, and the implementation of molecular typing has significantly increased the level of diversity revealing that many serotypes have multiple functional variants. While the degree of diversity in many populations is equivalent and may result from functional polymorphism(s) in peptide presentation, homogeneous and heterogeneous populations present contrasting numbers of alleles and lineages at the loci with high-density expression products. In spite of these differences, the homozygosity levels are comparable in almost all of them. The balanced distribution of HLA alleles is consistent with overdominant selection. The genetic distances between outbred populations correlate with their geographical locations; the formal genetic distance measurements are larger than expected between inbred populations in the same region. The latter present many unique alleles grouped in a few lineages consistent with limited founder polymorphism in which any novel allele may have been positively selected to enlarge the communal peptide-binding repertoire of a given population. On the other hand, it has been observed that some alleles are found in multiple populations with distinctive haplotypic associations suggesting that convergent evolution events may have taken place as well. It appears that the HLA system has been under strong selection, probably owing to its fundamental role in varying immune responses. Therefore, allelic diversity in HLA should be analysed in conjunction with other genetic markers to accurately track the migrations of modern humans. PMID:22312049

  6. Dwarf Rice Mutant Derived from 0.2 kGy Gamma Rays Irradiated Seeds of Atomita 4 Variety

    International Nuclear Information System (INIS)

    Sobrizal; Sutisna Sanjaya; Carkum; Mohamad Ismachin

    2004-01-01

    Dwarf rice mutant was obtained when Atomita 4 seeds were irradiated by 0.2 kGy gamma rays. The results of segregation analyses in F2 populations and F3 lines derived from reciprocal crosses of mutant and Atomita 4 suggested that the dwarf was controlled by a single recessive gene. This gene was not located on rice cytoplasmic genome but on nuclear genome. The gene for dwarf obtained in this study tentatively could be assumed as a new finding until the allelic relationships with other dwarf genes are verified. (author)

  7. Rapid identification of lettuce seed germination mutants by bulked segregant analysis and whole genome sequencing.

    Science.gov (United States)

    Huo, Heqiang; Henry, Isabelle M; Coppoolse, Eric R; Verhoef-Post, Miriam; Schut, Johan W; de Rooij, Han; Vogelaar, Aat; Joosen, Ronny V L; Woudenberg, Leo; Comai, Luca; Bradford, Kent J

    2016-11-01

    Lettuce (Lactuca sativa) seeds exhibit thermoinhibition, or failure to complete germination when imbibed at warm temperatures. Chemical mutagenesis was employed to develop lettuce lines that exhibit germination thermotolerance. Two independent thermotolerant lettuce seed mutant lines, TG01 and TG10, were generated through ethyl methanesulfonate mutagenesis. Genetic and physiological analyses indicated that these two mutations were allelic and recessive. To identify the causal gene(s), we applied bulked segregant analysis by whole genome sequencing. For each mutant, bulked DNA samples of segregating thermotolerant (mutant) seeds were sequenced and analyzed for homozygous single-nucleotide polymorphisms. Two independent candidate mutations were identified at different physical positions in the zeaxanthin epoxidase gene (ABSCISIC ACID DEFICIENT 1/ZEAXANTHIN EPOXIDASE, or ABA1/ZEP) in TG01 and TG10. The mutation in TG01 caused an amino acid replacement, whereas the mutation in TG10 resulted in alternative mRNA splicing. Endogenous abscisic acid contents were reduced in both mutants, and expression of the ABA1 gene from wild-type lettuce under its own promoter fully complemented the TG01 mutant. Conventional genetic mapping confirmed that the causal mutations were located near the ZEP/ABA1 gene, but the bulked segregant whole genome sequencing approach more efficiently identified the specific gene responsible for the phenotype. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  8. Meiotic UV-sensitive mutant that causes deletion of duplications in neurospora

    International Nuclear Information System (INIS)

    Newmeyer, D.; Galeazzi, D.R.

    1978-01-01

    The meiotic-3 (mei-3) mutant of Neurospora crassa has several effects: (1) when homozygous, it almost completely blocks meiosis and ascospore formation, (2) it is sensitive to uv, (3) its growth is inhibited by histidine, and (4) it increases the instability of nontandem duplications. This was shown for duplications produced by five different rearrangements and was demonstrated by two different criteria. The effects on meiosis and duplication instability are expressed strongly at 25 0 ; the effects on sensitivity to uv and to histidine are expressed strongly at 38.5 0 but only slightly at 25 0 . Nevertheless, all four effects were shown to be due to a single gene. Mei-3 is not allelic with previously reported uv-sensitive mutants. Two other results were obtained that are not necessarily due to mei-3: (1) a cross involving mei-3 produced a new unlinked meiotic mutant, mei-4, which is not sensitive to uv or histidine, and (2) a burst of several new mutants occurred in a different mei-3 stock, including a partial revertant to mei-3. Mei-3 has previously been shown to cause frequent complete loss of a terminal duplicate segment, beginning exactly at the original rearrangement breakpoint. Possible mechanisms are discussed by which a uv-sensitive mutant could cause such precise deletions

  9. Leishmania infantum HSP70-II null mutant as candidate vaccine against leishmaniasis: a preliminary evaluation

    Directory of Open Access Journals (Sweden)

    Fresno Manuel

    2011-07-01

    Full Text Available Abstract Background Visceral leishmaniasis is the most severe form of leishmaniasis and no effective vaccine exists. The use of live attenuated vaccines is emerging as a promising vaccination strategy. Results In this study, we tested the ability of a Leishmania infantum deletion mutant, lacking both HSP70-II alleles (ΔHSP70-II, to provide protection against Leishmania infection in the L. major-BALB/c infection model. Administration of the mutant line by either intraperitoneal, intravenous or subcutaneous route invariably leads to the production of high levels of NO and the development in mice of type 1 immune responses, as determined by analysis of anti-Leishmania IgG subclasses. In addition, we have shown that ΔHSP70-II would be a safe live vaccine as immunodeficient SCID mice, and hamsters (Mesocricetus auratus, infected with mutant parasites did not develop any sign of pathology. Conclusions The results suggest that the ΔHSP70-II mutant is a promising and safe vaccine, but further studies in more appropriate animal models (hamsters and dogs are needed to appraise whether this attenuate mutant would be useful as vaccine against visceral leishmaniasis.

  10. Conserved role of unc-79 in ethanol responses in lightweight mutant mice.

    Directory of Open Access Journals (Sweden)

    David J Speca

    2010-08-01

    Full Text Available The mechanisms by which ethanol and inhaled anesthetics influence the nervous system are poorly understood. Here we describe the positional cloning and characterization of a new mouse mutation isolated in an N-ethyl-N-nitrosourea (ENU forward mutagenesis screen for animals with enhanced locomotor activity. This allele, Lightweight (Lwt, disrupts the homolog of the Caenorhabditis elegans (C. elegans unc-79 gene. While Lwt/Lwt homozygotes are perinatal lethal, Lightweight heterozygotes are dramatically hypersensitive to acute ethanol exposure. Experiments in C. elegans demonstrate a conserved hypersensitivity to ethanol in unc-79 mutants and extend this observation to the related unc-80 mutant and nca-1;nca-2 double mutants. Lightweight heterozygotes also exhibit an altered response to the anesthetic isoflurane, reminiscent of unc-79 invertebrate mutant phenotypes. Consistent with our initial mapping results, Lightweight heterozygotes are mildly hyperactive when exposed to a novel environment and are smaller than wild-type animals. In addition, Lightweight heterozygotes exhibit increased food consumption yet have a leaner body composition. Interestingly, Lightweight heterozygotes voluntarily consume more ethanol than wild-type littermates. The acute hypersensitivity to and increased voluntary consumption of ethanol observed in Lightweight heterozygous mice in combination with the observed hypersensitivity to ethanol in C. elegans unc-79, unc-80, and nca-1;nca-2 double mutants suggests a novel conserved pathway that might influence alcohol-related behaviors in humans.

  11. Allelic diversity of the MHC class II DRB genes in brown bears (Ursus arctos) and a comparison of DRB sequences within the family Ursidae.

    Science.gov (United States)

    Goda, N; Mano, T; Kosintsev, P; Vorobiev, A; Masuda, R

    2010-11-01

    The allelic diversity of the DRB locus in major histocompatibility complex (MHC) genes was analyzed in the brown bear (Ursus arctos) from the Hokkaido Island of Japan, Siberia, and Kodiak of Alaska. Nineteen alleles of the DRB exon 2 were identified from a total of 38 individuals of U. arctos and were highly polymorphic. Comparisons of non-synonymous and synonymous substitutions in the antigen-binding sites of deduced amino acid sequences indicated evidence for balancing selection on the bear DRB locus. The phylogenetic analysis of the DRB alleles among three genera (Ursus, Tremarctos, and Ailuropoda) in the family Ursidae revealed that DRB allelic lineages were not separated according to species. This strongly shows trans-species persistence of DRB alleles within the Ursidae. © 2010 John Wiley & Sons A/S.

  12. PNRI mutant variety: Cordyline 'Afable'

    International Nuclear Information System (INIS)

    Aurigue, Fernando B.

    2012-01-01

    Cordyline 'Afable', registered by the Philippine Nuclear Research Institute as NSIC 2009 Or-83, is an induced mutant developed from Cordyline 'Kiwi' by treating stem cuttings with acute gamma radiation from a Cobalt-60 source. The new mutant is identical to Cordyline 'Kiwi' in growth habit but differs in foliage color, and exhibits field resistance to Phytophthora sp., a fungus that causes leaf blight and rot in Ti plants. Results of this mutation breeding experiment showed that leaf color was altered by gamma irradiation and resistance to fungal diseases was improved. It also demonstrated how mutations that occur in nature may be generated artificially. Propagation of cordyline 'Afable' is true-to-type by vegetative propagation methods, such as separation of suckers and offshoots, shoot tip cutting, and top cutting. Aside from landscaping material, terrarium or dish-garden plant, it is ideal as containerized plant for indoor and outdoor use. The leaves or shoots may be harvested as cut foliage for flower arrangements. (author)

  13. Gamma ray induced mutants in Coleus

    International Nuclear Information System (INIS)

    Vasudevan, K.; Jos, J.S.

    1988-01-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M 1 V 1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m 2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

  14. Gamma ray induced mutants in Coleus

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, K; Jos, J S [Central Tuber Crops Research Institute, Trivandrum, Kerala (India)

    1988-07-01

    The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M{sub 1}V{sub 1} generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m{sup 2} area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing.

  15. Targeted Disruption of V600E-Mutant BRAF Gene by CRISPR-Cpf1

    Directory of Open Access Journals (Sweden)

    Meijia Yang

    2017-09-01

    Full Text Available BRAF-V600E (1799T > A is one of the most frequently reported driver mutations in multiple types of cancers, and patients with such mutations could benefit from selectively inactivating the mutant allele. Near this mutation site, there are two TTTN and one NGG protospacer-adjacent motifs (PAMs for Cpf1 and Cas9 CRISPR nucleases, respectively. The 1799T > A substitution also leads to the occurrence of a novel NGNG PAM for the EQR variant of Cas9. We examined the editing efficacy and selectivity of Cpf1, Cas9, and EQR variant to this mutation site. Only Cpf1 demonstrated robust activity to induce specific disruption of only mutant BRAF, not wild-type sequence. Cas9 recognized and cut both normal and mutant alleles, and no obvious gene editing events were observed using EQR variant. Our results support the potential applicability of Cpf1 in precision medicine through highly specific inactivation of many other gain-of-function mutations. Keywords: Cpf1, targeted therapy, BRAF V600E

  16. A new mutant gene su-1 in corn obtained by irradiation with low doses of gamma rays

    International Nuclear Information System (INIS)

    Diaconu, P.

    1993-01-01

    This paper provides a description of a sugar corn mutant obtained by irradiation of wetted kernels of Romanesc de Studina variety with low doses of gamma rays (300 R). This mutant influences the structure of the endosperm similarly to the su-1 genes developed spontaneously which resulted in the corn variety Zea mays saccharata thousands of years ago. Although the mutant is a multiple allele of the su-1 locus in chromosome IV it differs widely from the spontaneous mutant. The length of the ears is much reduced, varying between 4 and 6 cm, with numbers of kernels per ear varying between 45 and 72. Attempts to improve the cob size and the number of kernels by breeding and propagation in an insulated area led to no result. Crossing the mutants with the sugar hybrid Delicious resulted in sugar type progeny which confirms the common position of the mutant gene induced by irradiation and the spontaneous su-1 gene. The progenies of sugar mutant x Delicious are 38-43 % lower in cob vigor and 36-46% lower in kernel number. (author). 2 figs, 2 tab., 16 refs

  17. A method for the production and expedient screening of CRISPR/Cas9-mediated non-transgenic mutant plants.

    Science.gov (United States)

    Chen, Longzheng; Li, Wei; Katin-Grazzini, Lorenzo; Ding, Jing; Gu, Xianbin; Li, Yanjun; Gu, Tingting; Wang, Ren; Lin, Xinchun; Deng, Ziniu; McAvoy, Richard J; Gmitter, Frederick G; Deng, Zhanao; Zhao, Yunde; Li, Yi

    2018-01-01