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Sample records for mutation affecting symbiosis

  1. Ectomycorrhizal symbiosis affects functional diversity of rhizosphere fluorescent pseudomonads.

    PubMed

    Frey-Klett, Pascale; Chavatte, Michaël; Clausse, Marie-Lise; Courrier, Sébastien; Le Roux, Christine; Raaijmakers, Jos; Martinotti, Maria Giovanna; Pierrat, Jean-Claude; Garbaye, Jean

    2005-01-01

    Here we characterized the effect of the ectomycorrhizal symbiosis on the genotypic and functional diversity of soil Pseudomonas fluorescens populations and analysed its possible consequences in terms of plant nutrition, development and health. Sixty strains of P. fluorescens were isolated from the bulk soil of a forest nursery, the ectomycorrhizosphere and the ectomycorrhizas of the Douglas fir (Pseudostuga menziesii) seedlings-Laccaria bicolor S238N. They were characterized in vitro with the following criteria: ARDRA, phosphate solubilization, siderophore, HCN and AIA production, genes of N2-fixation and antibiotic synthesis, in vitro confrontation with a range of phytopathogenic and ectomycorrhizal fungi, effect on the Douglas fir-L. bicolor symbiosis. For most of these criteria, we demonstrated that the ectomycorrhizosphere significantly structures the P. fluorescens populations and selects strains potentially beneficial to the symbiosis and to the plant. This prompts us to propose the ectomycorrhizal symbiosis as a true microbial complex where multitrophic interactions take place. Moreover it underlines the fact that this symbiosis has an indirect positive effect on plant growth, via its selective pressure on bacterial communities, in addition to its known direct positive effect. PMID:15720643

  2. Interaction between host genotype and environmental conditions affects bacterial density in Wolbachia symbiosis.

    PubMed

    Mouton, Laurence; Henri, Hélène; Charif, Delphine; Boulétreau, Michel; Vavre, Fabrice

    2007-04-22

    Regulation of microbial population density is a necessity in stable symbiotic interactions. In Wolbachia symbiosis, both bacterial and host genotypes are involved in density regulation, but environmental factors may also affect bacterial population density. Here, we studied the interaction between three strains of Wolbachia in two divergent homozygous lines of the wasp Leptopilina heterotoma at two different temperatures. Wolbachia density varied between the two host genotypes at only one temperature. Moreover, at this temperature, reciprocal-cross F1 insects displayed identical Wolbachia densities, which were intermediate between the densities in the two parental lines. While these findings confirm that the host genotype plays an important role in Wolbachia density, they also highlight its interaction with environmental conditions, making possible the evolution of local adaptations for the regulation of Wolbachia density. PMID:17251124

  3. How mutation affects evolutionary games on graphs.

    PubMed

    Allen, Benjamin; Traulsen, Arne; Tarnita, Corina E; Nowak, Martin A

    2012-04-21

    Evolutionary dynamics are affected by population structure, mutation rates and update rules. Spatial or network structure facilitates the clustering of strategies, which represents a mechanism for the evolution of cooperation. Mutation dilutes this effect. Here we analyze how mutation influences evolutionary clustering on graphs. We introduce new mathematical methods to evolutionary game theory, specifically the analysis of coalescing random walks via generating functions. These techniques allow us to derive exact identity-by-descent (IBD) probabilities, which characterize spatial assortment on lattices and Cayley trees. From these IBD probabilities we obtain exact conditions for the evolution of cooperation and other game strategies, showing the dual effects of graph topology and mutation rate. High mutation rates diminish the clustering of cooperators, hindering their evolutionary success. Our model can represent either genetic evolution with mutation, or social imitation processes with random strategy exploration.

  4. How Symbiosis Creates Diversity

    ERIC Educational Resources Information Center

    Lord, Joshua

    2010-01-01

    Diversity in habitats on Earth is astounding--whether on land or in the sea--and this is in part due to symbiosis. The lesson described in this article helps students understand how symbiosis affects different organisms through a fun and engaging game where they match hosts and symbionts based on their respective needs. This 45-minute lesson is…

  5. Mutations affecting gonadotropin secretion and action.

    PubMed

    Huhtaniemi, Ilpo

    2003-01-01

    A number of mutations are known to disturb the development and function of the hypothalamic-pituitary-gonadal axis. They affect hypothalamic-pituitary-gonadal function at multiple levels, from the migration of gonadotropin releasing hormone neurons to the hypothalamus right through to gonadotropin action in the ovary and testis. Most of the mutations are inactivating, causing various forms of hypogonadism. Exceptions are the activating mutations of the luteinizing hormone receptor, causing male-limited gonadotropin-independent precocious puberty. The human mutations and genetically modified animal models have clarified the molecular pathogenesis of hypogonadism and such disorders can now be diagnosed using molecular biological techniques, enabling selection of specific treatments and appropriate counselling of patients and their families.

  6. Symbiosis between nitrogen-fixing bacteria and Medicago truncatula is not significantly affected by silver and silver sulfide nanomaterials.

    PubMed

    Judy, Jonathan D; Kirby, Jason K; McLaughlin, Mike J; McNear, David; Bertsch, Paul M

    2016-07-01

    Silver (Ag) engineered nanomaterials (ENMs) are being released into waste streams and are being discharged, largely as Ag2S aged-ENMs (a-ENMs), into agroecosystems receiving biosolids amendments. Recent research has demonstrated that biosolids containing an environmentally relevant mixture of ZnO, TiO2, and Ag ENMs and their transformation products, including Ag2S a-ENMs, disrupted the symbiosis between nitrogen-fixing bacteria and legumes. However, this study was unable to unequivocally determine which ENM or combination of ENMs and a-ENMs was responsible for the observed inhibition. Here, we examined further the effects of polyvinylpyrollidone (PVP) coated pristine Ag ENMs (PVP-Ag), Ag2S a-ENMs, and soluble Ag (as AgSO4) at 1, 10, and 100 mg Ag kg(-1) on the symbiosis between the legume Medicago truncatula and the nitrogen-fixing bacterium, Sinorhizobium melliloti in biosolids-amended soil. Nodulation frequency, nodule function, glutathione reductase production, and biomass were not significantly affected by any of the Ag treatments, even at 100 mg kg(-1), a concentration analogous to a worst-case scenario resulting from long-term, repeated biosolids amendments. Our results provide additional evidence that the disruption of the symbiosis between nitrogen-fixing bacteria and legumes in response to a mixture of ENMs in biosolids-amended soil reported previously may not be attributable to Ag ENMs or their transformation end-products. We anticipate these findings will provide clarity to regulators and industry regarding potential unintended consequences to terrestrial ecosystems resulting from of the use of Ag ENMs in consumer products. PMID:27149150

  7. Arbuscular mycorrhizal symbiosis affects the grain proteome of Zea mays: a field study

    PubMed Central

    Bona, Elisa; Scarafoni, Alessio; Marsano, Francesco; Boatti, Lara; Copetta, Andrea; Massa, Nadia; Gamalero, Elisa; D’Agostino, Giovanni; Cesaro, Patrizia; Cavaletto, Maria; Berta, Graziella

    2016-01-01

    Maize is one of the most important crops worldwide and is strongly dependent on arbuscular mycorrhiza (AM) fungi, organisms that form a mutualistic association with land plants. In maize, AM symbiosis enhances spike dry weight, spike length, spike circumference, and the dry weight and dimensions of the grain. Notwithstanding its ubiquitous nature, the detailed relationship between AM fungal colonization and plant development is not completely understood. To facilitate a better understanding of the effects of AM fungi on plants, the work reported here assessed the effects of a consortium of AM fungi on the kernel proteome of maize, cultivated in open-field conditions. To our knowledge, this is the first report of the modulation of a plant seed proteome following AM fungal inoculation in the field. Here, it was found that AM fungi modify the maize seed proteome by up-regulating enzymes involved in energetic metabolism, embryo development, nucleotide metabolism, seed storage and stress responses. PMID:27216714

  8. Schoolyard Symbiosis.

    ERIC Educational Resources Information Center

    Allard, David W.

    1996-01-01

    Discusses different types of symbiosis--mutualism, commensalism, and parasitism--and examples of each type including lichens, legumes, mistletoe, and epiphytes. Describes how teachers can use these examples in the study of symbiosis which allows teachers to focus on many basic concepts in evolution, cell biology, ecology, and other fields of…

  9. Mycorrhizal symbiosis in leeks increases plant growth under low phosphorus and affects the levels of specific flavonoid glycosides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction- Mycorrhizae symbiosis is a universal phenomenon in nature that promotes plant growth and food quality in most plants, especially, under phosphorus deficiency and water stress. Objective- The objective of this study was to assess the effects of mycorrhizal symbiosis on changes in the le...

  10. Metal toxicity differently affects the Iris pseudacorus-arbuscular mycorrhiza fungi symbiosis in terrestrial and semi-aquatic habitats.

    PubMed

    Wężowicz, K; Turnau, K; Anielska, T; Zhebrak, I; Gołuszka, K; Błaszkowski, J; Rozpądek, P

    2015-12-01

    Phytoremediation offers an environmental friendly alternative to conventional cleanup techniques. In this study, mycorrhizal fungi isolated from the roots of Mentha longifolia grown in the basin of the Centuria River (S Poland) were used. Iris pseudacorus was grown in substratum from an industrial waste, enriched in Pb, Fe, Zn, and Cd in a terrestrial and water-logged habitat. Plant yield and photosynthetic performance was the highest in the aquatic environment; however, the presence of toxic metals (TM) negatively affected photosystem II (PSII) photochemistry as shown by the JIP test. Fungi colonization and Cd accumulation within plant tissues was decreased. In the terrestrial habitat, neither arbuscular mycorrhizal fungi (AMF) nor metal toxicity affected plant growth, although metal uptake, Cd in particular, as well as photosynthesis were affected. Inoculated plants accumulated significantly more Cd, and photosynthesis was downregulated. The results presented in this study clearly indicate that the I. pseudacorus-AMF symbiosis adapts itself to the presence of toxic metals in the environment, optimizing resource supply, energy fluxes, and possibly stress tolerance mechanisms. Plant/AMF consortia grown in terrestrial and water-logged habitats utilize different strategies to cope with metal toxicity. The use of AMF in improving the phytoremediation potential of I. pseudacorus needs, however, further research.

  11. Metal toxicity differently affects the Iris pseudacorus-arbuscular mycorrhiza fungi symbiosis in terrestrial and semi-aquatic habitats.

    PubMed

    Wężowicz, K; Turnau, K; Anielska, T; Zhebrak, I; Gołuszka, K; Błaszkowski, J; Rozpądek, P

    2015-12-01

    Phytoremediation offers an environmental friendly alternative to conventional cleanup techniques. In this study, mycorrhizal fungi isolated from the roots of Mentha longifolia grown in the basin of the Centuria River (S Poland) were used. Iris pseudacorus was grown in substratum from an industrial waste, enriched in Pb, Fe, Zn, and Cd in a terrestrial and water-logged habitat. Plant yield and photosynthetic performance was the highest in the aquatic environment; however, the presence of toxic metals (TM) negatively affected photosystem II (PSII) photochemistry as shown by the JIP test. Fungi colonization and Cd accumulation within plant tissues was decreased. In the terrestrial habitat, neither arbuscular mycorrhizal fungi (AMF) nor metal toxicity affected plant growth, although metal uptake, Cd in particular, as well as photosynthesis were affected. Inoculated plants accumulated significantly more Cd, and photosynthesis was downregulated. The results presented in this study clearly indicate that the I. pseudacorus-AMF symbiosis adapts itself to the presence of toxic metals in the environment, optimizing resource supply, energy fluxes, and possibly stress tolerance mechanisms. Plant/AMF consortia grown in terrestrial and water-logged habitats utilize different strategies to cope with metal toxicity. The use of AMF in improving the phytoremediation potential of I. pseudacorus needs, however, further research. PMID:26585452

  12. Mutations affecting enzymatic activity in liver arginase

    SciTech Connect

    Vockley, J.G.; Tabor, D.E.; Goodman, B.K.

    1994-09-01

    The hydrolysis of arginine to ornithine and urea is catalyzed by arginase in the last step of the urea cycle. We examined a group of arginase deficient patients by PCR-SSCP analysis to characterize the molecular basis of this disorder. A heterogeneous population of nonsense mutations, microdeletions, and missense mutations has been identified in our cohort. Microdeletions which introduce premature stop codons downstream of the deletion and nonsense mutations result in no arginase activity. These mutations occur randomly along the gene. The majority of missense mutations identified appear to occur in regions of high cross-species homology. To test the effect of these missense mutations on arginase activity, site-directed mutagenesis was used to re-create the patient mutations for in vivo expression studies in a prokaryotic fusion-protein expression system. Of 4 different missense mutations identified in 6 individuals, only one was located outside of a conserved region. The three substitution mutations within the conserved regions had a significant effect on enzymatic activity (0-3.1 nmole/30min, normal is 1300-1400 nmoles/30min, as determined by in vitro arginase assay), while the fourth mutation, a T to S substitution, did not. In addition, site-directed mutagenesis was utilized to create mutations not in residues postulated to play a significant role in the enzymatic function or active site formation in manganese-binding proteins such as arginase. We have determined that the substitution of glycine for a histidine residue, located in a very highly conserved region of exon 3, and the substitution of a histidine and an aspartic acid residue within a similarly conserved region in exon 4, totally abolishes enzymatic activity. Mutations substituting glycine for an additional histidine and aspartic acid residue in exon 4 and two aspartic acid residues in exon 7 have also been created. We are currently in the process of characterizing these mutations.

  13. New mutations affecting induced mutagenesis in yeast.

    PubMed

    Lawrence, C W; Krauss, B R; Christensen, R B

    1985-01-01

    Previously isolated mutations in baker's yeast, Saccharomyces cerevisiae, that impair induced mutagenesis were all identified with the aid of tests that either exclusively or predominantly detect base-pair substitutions. To avoid this bias, we have screened 11 366 potentially mutant clones for UV-induced reversion of the frameshift allele, his4-38, and have identified 10 mutants that give much reduced yields of revertants. Complementation and recombination tests show that 6 of these carry mutations at the previously known REV1, REV1 and REV3 loci, while the remaining 4 define 3 new genes, REV4 (2 mutations), REV5 and REV6. The rev4 mutations are readily suppressed in many genetic backgrounds and, like the rev5 mutation, impart only a limited deficiency for induced mutagenesis: it is likely, therefore that the REV4+ and REV5+ gene functions are only remotely concerned with this process. The rev6 mutants have a more general deficiency, however, as well as marked sensitivity to UV and an increased spontaneous mutation rate, properties that suggest the REV6 gene is directly involved in mutation induction. The REV5 gene is located about 1 cM proximal to CYC1 on chromosome X.

  14. Teaching Symbiosis.

    ERIC Educational Resources Information Center

    Harper, G. H.

    1985-01-01

    Argues that the meaning of the word "symbiosis" be standardized and that it should be used in a broad sense. Also criticizes the orthodox teaching of general principles in this subject and recommends that priority be given to continuity, intimacy, and associated adaptations, rather than to the harm/benefit relationship. (Author/JN)

  15. Differentiation as symbiosis.

    PubMed

    Chigira, M; Watanabe, H

    1994-07-01

    Preservation of the identity of DNA is the ultimate goal of multicellular organisms. An abnormal DNA sequence in cells within an individual means its parasitic nature in cell society as shown in tumors. Somatic gene arrangement and gene mutation in development may be considered as de novo formation of parasites. It is likely that the developmental process with genetic alterations means symbiosis between altered cells and germ line cells preserving genetic information without alterations, when somatic alteration of DNA sequence is a major mechanism of differentiation. According to the selfish gene theory of Dawkins, germ line cells permit symbiosis when somatic cell society derives clear profit for the replication of original DNA copies. PMID:7968715

  16. Analysis of Dominant Mutations Affecting Muscle Excitation in Caenorhabditis Elegans

    PubMed Central

    Reiner, D. J.; Weinshenker, D.; Thomas, J. H.

    1995-01-01

    We examined mutations that disrupt muscle activation in Caenorhabditis elegans. Fifteen of 17 of these genes were identified previously and we describe new mutations in three of them. We also describe mutations in two new genes, exp-3 and exp-4. We assessed the degree of defect in pharyngeal, body-wall, egg-laying, and enteric muscle activation in animals mutant for each gene. Mutations in all 17 genes are semidominant and, in cases that could be tested, appear to be gain-of-function. Based on their phenotypes, the genes fall into three broad categories: mutations in 11 genes cause defective muscle activation, mutations in four genes cause hyperactivated muscle, and mutations in two genes cause defective activation in some muscle types and hyperactivation in others. In all testable cases, the mutations blocked response to pharmacological activators of egg laying, but did not block muscle activation by irradiation with a laser microbeam. The data suggest that these mutations affect muscle excitation, but not the capacity of the muscle fibers to contract. For most of the genes, apparent loss-of-function mutants have a grossly wild-type phenotype. These observations suggest that there is a large group of genes that function in muscle excitation that can be identified primarily by dominant mutations. PMID:8582640

  17. Large-scale mapping of mutations affecting zebrafish development

    PubMed Central

    Geisler, Robert; Rauch, Gerd-Jörg; Geiger-Rudolph, Silke; Albrecht, Andrea; van Bebber, Frauke; Berger, Andrea; Busch-Nentwich, Elisabeth; Dahm, Ralf; Dekens, Marcus PS; Dooley, Christopher; Elli, Alexandra F; Gehring, Ines; Geiger, Horst; Geisler, Maria; Glaser, Stefanie; Holley, Scott; Huber, Matthias; Kerr, Andy; Kirn, Anette; Knirsch, Martina; Konantz, Martina; Küchler, Axel M; Maderspacher, Florian; Neuhauss, Stephan C; Nicolson, Teresa; Ober, Elke A; Praeg, Elke; Ray, Russell; Rentzsch, Brit; Rick, Jens M; Rief, Eva; Schauerte, Heike E; Schepp, Carsten P; Schönberger, Ulrike; Schonthaler, Helia B; Seiler, Christoph; Sidi, Samuel; Söllner, Christian; Wehner, Anja; Weiler, Christian; Nüsslein-Volhard, Christiane

    2007-01-01

    Background Large-scale mutagenesis screens in the zebrafish employing the mutagen ENU have isolated several hundred mutant loci that represent putative developmental control genes. In order to realize the potential of such screens, systematic genetic mapping of the mutations is necessary. Here we report on a large-scale effort to map the mutations generated in mutagenesis screening at the Max Planck Institute for Developmental Biology by genome scanning with microsatellite markers. Results We have selected a set of microsatellite markers and developed methods and scoring criteria suitable for efficient, high-throughput genome scanning. We have used these methods to successfully obtain a rough map position for 319 mutant loci from the Tübingen I mutagenesis screen and subsequent screening of the mutant collection. For 277 of these the corresponding gene is not yet identified. Mapping was successful for 80 % of the tested loci. By comparing 21 mutation and gene positions of cloned mutations we have validated the correctness of our linkage group assignments and estimated the standard error of our map positions to be approximately 6 cM. Conclusion By obtaining rough map positions for over 300 zebrafish loci with developmental phenotypes, we have generated a dataset that will be useful not only for cloning of the affected genes, but also to suggest allelism of mutations with similar phenotypes that will be identified in future screens. Furthermore this work validates the usefulness of our methodology for rapid, systematic and inexpensive microsatellite mapping of zebrafish mutations. PMID:17212827

  18. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover

    PubMed Central

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca2+-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  19. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover.

    PubMed

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca(2+)-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  20. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover

    PubMed Central

    Rachwał, Kamila; Boguszewska, Aleksandra; Kopcińska, Joanna; Karaś, Magdalena; Tchórzewski, Marek; Janczarek, Monika

    2016-01-01

    Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca2+-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with

  1. Computer symbiosis: Emergence of symbiotic behavior through evolution

    SciTech Connect

    Ikegami, Takashi; Kaneko, Kunihiko

    1989-01-01

    Symbiosis is altruistic cooperation between distinct species. It is one of the most effective evolutionary processes, but its dynamics are not well understood as yet. A simple model of symbiosis is introduced, where we consider interactions between hosts and parasites and also mutations of hosts and parasites. It is found that a symbiotic state emerges for a suitable range of mutation rates. The symbiotic state is not static, but dynamically oscillates. Harmful parasites violating symbiosis appear periodically, but are rapidly extinguished by hosts and other parasites, and the symbiotic state is recovered. The emergence of ''Tit for Tat'' strategy to maintain symbiosis is discussed. 4 figs.

  2. Lipopolysaccharide mutants of Rhizobium meliloti are not defective in symbiosis

    SciTech Connect

    Clover, R.H.; Kieber, J.; Signer, E.R. )

    1989-07-01

    Mutants of Rhizobium meliloti selected primarily for bacteriophage resistance fall into 13 groups. Mutants in the four best-characterized groups (class A, lpsB, lpsC, and class D), which map to the rhizobial chromosome, appear to affect lipopolysaccharide (LPS) as judged by the reactivity with monoclonal antibodies and behavior on sodium dodecyl sulfate-polyacrylamide gels of extracted LPS. Mutations in all 13 groups, in an otherwise wild-type genetic background, are Fix{sup +} on alfalfa. This suggests that LPS does not play a major role in symbiosis. Mutations in lpsB, however, are Fix{sup {minus}} in one particular genetic background, evidently because of the cumulative effect of several independent background mutations. In addition, an auxotrophic mutation evidently equivalent to Escherichia coli carAB is Fix{sup {minus}} on alfalfa.

  3. Prediction of disease-related mutations affecting protein localization

    PubMed Central

    Laurila, Kirsti; Vihinen, Mauno

    2009-01-01

    Background Eukaryotic cells contain numerous compartments, which have different protein constituents. Proteins are typically directed to compartments by short peptide sequences that act as targeting signals. Translocation to the proper compartment allows a protein to form the necessary interactions with its partners and take part in biological networks such as signalling and metabolic pathways. If a protein is not transported to the correct intracellular compartment either the reaction performed or information carried by the protein does not reach the proper site, causing either inactivation of central reactions or misregulation of signalling cascades, or the mislocalized active protein has harmful effects by acting in the wrong place. Results Numerous methods have been developed to predict protein subcellular localization with quite high accuracy. We applied bioinformatics methods to investigate the effects of known disease-related mutations on protein targeting and localization by analyzing over 22,000 missense mutations in more than 1,500 proteins with two complementary prediction approaches. Several hundred putative localization affecting mutations were identified and investigated statistically. Conclusion Although alterations to localization signals are rare, these effects should be taken into account when analyzing the consequences of disease-related mutations. PMID:19309509

  4. Mutations affecting expression of the rosy locus in Drosophila melanogaster

    SciTech Connect

    Lee, C.S.; Curtis, D.; McCarron, M.; Love, C.; Gray, M.; Bender, W.; Chovnick, A.

    1987-05-01

    The rosy locus in Drosophila melanogaster codes for the enzyme xanthine dehydrogenase (XDH). Previous studies defined a control element near the 5' end of the gene, where variant sites affected the amount of rosy mRNA and protein produced. The authors have determined the DNA sequence of this region from both genomic and cDNA clones, and from the ry/sup +10/ underproducer strain. This variant strain had many sequence differences, so that the site of the regulatory change could not be fixed. A mutagenesis was also undertaken to isolate new regulatory mutations. They induced 376 new mutations with 1-ethyl-1-nitrosourea (ENU) and screened them to isolate those that reduced the amount of XDH protein produced, but did not change the properties of the enzyme. Genetic mapping was used to find mutations located near the 5' end of the gene. DNA from each of seven mutants was cloned and sequenced through the 5' region. Mutant base changes were identified in all seven; they appear to affect splicing and translation of the rosy mRNA. In a related study, the genomic and cDNA sequences are extended through the 3' end of the gene; the combined sequences define the processing pattern of the rosy transcript and predict the amino acid sequence of XDH.

  5. Plant hormones as signals in arbuscular mycorrhizal symbiosis.

    PubMed

    Miransari, Mohammad; Abrishamchi, A; Khoshbakht, K; Niknam, V

    2014-06-01

    Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on mycorrhizal fungal symbiosis are reviewed. This may be useful for the production of plants, which are more responsive to mycorrhizal symbiosis under stress.

  6. Inflammatory Bowel Disease and Mutations Affecting the Interleukin-10 Receptor

    PubMed Central

    Glocker, Erik-Oliver; Kotlarz, Daniel; Boztug, Kaan; Gertz, E. Michael; Schäffer, Alejandro A.; Noyan, Fatih; Perro, Mario; Diestelhorst, Jana; Allroth, Anna; Murugan, Dhaarini; Hätscher, Nadine; Pfeifer, Dietmar; Sykora, Karl-Walter; Sauer, Martin; Kreipe, Hans; Lacher, Martin; Nustede, Rainer; Woellner, Cristina; Baumann, Ulrich; Salzer, Ulrich; Koletzko, Sibylle; Shah, Neil; Segal, Anthony W.; Sauerbrey, Axel; Buderus, Stephan; Snapper, Scott B.; Grimbacher, Bodo; Klein, Christoph

    2009-01-01

    BACKGROUND The molecular cause of inflammatory bowel disease is largely unknown. METHODS We performed genetic-linkage analysis and candidate-gene sequencing on samples from two unrelated consanguineous families with children who were affected by early-onset inflammatory bowel disease. We screened six additional patients with early-onset colitis for mutations in two candidate genes and carried out functional assays in patients’ peripheral-blood mononuclear cells. We performed an allogeneic hematopoietic stem-cell transplantation in one patient. RESULTS In four of nine patients with early-onset colitis, we identified three distinct homozygous mutations in genes IL10RA and IL10RB, encoding the IL10R1 and IL10R2 proteins, respectively, which form a heterotetramer to make up the interleukin-10 receptor. The mutations abrogate interleukin-10–induced signaling, as shown by deficient STAT3 (signal transducer and activator of transcription 3) phosphorylation on stimulation with interleukin-10. Consistent with this observation was the increased secretion of tumor necrosis factor α and other proinflammatory cytokines from peripheral-blood mononuclear cells from patients who were deficient in IL10R subunit proteins, suggesting that interleukin-10–dependent “negative feedback” regulation is disrupted in these cells. The allogeneic stem-cell transplantation performed in one patient was successful. CONCLUSIONS Mutations in genes encoding the IL10R subunit proteins were found in patients with early-onset enterocolitis, involving hyperinflammatory immune responses in the intestine. Allogeneic stem-cell transplantation resulted in disease remission in one patient. PMID:19890111

  7. Mutations affecting the chemosensory neurons of Caenorhabditis elegans

    SciTech Connect

    Starich, T.A.; Herman, R.K.; Kari, C.K.

    1995-01-01

    We have identified and characterized 95 mutations that reduce or abolish dye filling of amphid and phasmid neurons and that have little effect on viability, fertility or movement. Twenty-seven mutations occurred spontaneously in strains with a high frequency of transposon insertion. Sixty-eight were isolated after treatment with EMS. All of the mutations result in defects in one or more chemosensory responses, such as chemotaxis to ammonium chloride or formation of dauer larvae under conditions of starvation and overcrowding. Seventy-five of the mutations are alleles of 12 previously defined genes, mutations which were previously shown to lead to defects in amphid ultrastructure. We have assigned 20 mutations to 13 new genes, called dyf-1 through dyf-13. We expect that the genes represented by dye-filling defective mutants are important for the differentiation of amphid and phasmid chemosensilla. 58 refs., 3 figs., 6 tabs.

  8. Novel bacteriophage lambda mutation affecting lambda head assembly.

    PubMed Central

    Georgopoulos, C P; Bisig, R; Magazin, M; Eisen, H; Court, D

    1979-01-01

    A novel phage lambda mutation, called dc10, which interferes with proper lambda head assembly has been isolated and characterized. Phage lambda carrying this mutation is (i) unable to form plaques at 30 or 37 degrees C but does so at 42 degrees C and (ii) unable to form plaques at 42 degrees C on pN-constitutive hosts. Both properties are due to dc10 since all phage revertants for one phenotype simultaneously lose the other phenotype and vice versa. The dc10 mutation has been mapped in the B gene and has been shown to be dominant over the corresponding wild-type product. At 30 degrees C the dc10 mutation results in the formation of abnormal petit lambda heads made up of pE, pB, pC, and pNu3. Under pN-constitutive conditions, the dc10 mutation results in the formation of abnormal petit lambda heads made of pE, X1, and X2 only. A model to explain the data is presented. Images PMID:430610

  9. Genetic Screens for Mutations Affecting Development of Xenopus tropicalis

    PubMed Central

    Clark, Matthew D; Stemple, Derek L; Zimmerman, Lyle B

    2006-01-01

    We present here the results of forward and reverse genetic screens for chemically-induced mutations in Xenopus tropicalis. In our forward genetic screen, we have uncovered 77 candidate phenotypes in diverse organogenesis and differentiation processes. Using a gynogenetic screen design, which minimizes time and husbandry space expenditures, we find that if a phenotype is detected in the gynogenetic F2 of a given F1 female twice, it is highly likely to be a heritable abnormality (29/29 cases). We have also demonstrated the feasibility of reverse genetic approaches for obtaining carriers of mutations in specific genes, and have directly determined an induced mutation rate by sequencing specific exons from a mutagenized population. The Xenopus system, with its well-understood embryology, fate map, and gain-of-function approaches, can now be coupled with efficient loss-of-function genetic strategies for vertebrate functional genomics and developmental genetics. PMID:16789825

  10. Nonsense mutations in the human. beta. -globin gene affect mRNA metabolism

    SciTech Connect

    Baserga, S.J.; Benz, E.J. Jr. )

    1988-04-01

    A number of premature translation termination mutations (nonsense mutations) have been described in the human {alpha}- and {beta}-globin genes. Studies on mRNA isolated from patients with {beta}{sup 0}-thalassemia have shown that for both the {beta}-17 and the {beta}-39 mutations less than normal levels of {beta}-globin mRNA accumulate in peripheral blood cells. (The codon at which the mutation occurs designates the name of the mutation; there are 146 codons in human {beta}-globin mRNA). In vitro studies using the cloned {beta}-39 gene have reproduced this effect in a heterologous transfection system and have suggested that the defect resides in intranuclear metabolism. The authors have asked if this phenomenon of decreased mRNA accumulation is a general property of nonsense mutations and if the effect depends on the location or the type of mutation. Toward this end, they have studied the effect of five nonsense mutations and two missense mutations on the expression of human {beta}-globin mRNA in a heterologous transfection system. In all cases studied, the presence of a translation termination codon correlates with a decrease in the steady-state level of mRNA. The data suggest that the metabolism of a mammalian mRNA is affected by the presence of a mutation that affects translation.

  11. Mutations in Coliphage P1 Affecting Host Cell Lysis

    PubMed Central

    Walker, Jean Tweedy; Walker, Donald H.

    1980-01-01

    A total of 103 amber mutants of coliphage P1 were tested for lysis of nonpermissive cells. Of these, 83 caused cell lysis at the normal lysis time and have defects in particle morphogenesis. Five amber mutants, with mutations in the same gene (gene 2), caused premature lysis and may have a defect in a lysis regulator. Fifteen amber mutants were unable to cause cell lysis. Artificially lysed cells infected with five of these mutants produced viable phage particles, and phage particles were seen in thin sections of unlysed, infected cells. However, phage production by these mutants was not continued after the normal lysis time. We conclude that the defect of these five mutants is in a lysis function. The five mutations were found to be in the same gene (designated gene 17). The remaining 10 amber mutants, whose mutations were found to be in the same gene (gene 10), were also unable to cause cell lysis. They differed from those in gene 17 in that no viable phage particles were produced from artificially lysed cells, and no phage particles were seen in thin sections of unlysed, infected cells. We conclude that the gene 10 mutants cannot synthesize late proteins, and it is possible that gene 10 may code for a regulator of late gene expression for P1. Images PMID:16789200

  12. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition.

    PubMed

    Jarvis, P; Belzile, F; Page, T; Dean, C

    1997-05-01

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity.

  13. Large family with both parents affected by distinct BRCA1 mutations: implications for genetic testing

    PubMed Central

    Sokolenko, Anna P; Voskresenskiy, Dmitry A; Iyevleva, Aglaya G; Bit-Sava, Elena M; Gutkina, Nadezhda I; Anisimenko, Maxim S; Yu Sherina, Nathalia; Mitiushkina, Nathalia V; Ulibina, Yulia M; Yatsuk, Olga S; Zaitseva, Olga A; Suspitsin, Evgeny N; Togo, Alexandr V; Pospelov, Valery A; Kovalenko, Sergey P; Semiglazov, Vladimir F; Imyanitov, Evgeny N

    2009-01-01

    Although the probability of both parents being affected by BRCA1 mutations is not negligible, such families have not been systematically described in the literature. Here we present a large breast-ovarian cancer family, where 3 sisters and 1 half-sister inherited maternal BRCA1 5382insC mutation while the remaining 2 sisters carried paternal BRCA1 1629delC allele. No BRCA1 homozygous mutations has been detected, that is consistent with the data on lethality of BRCA1 knockout mice. This report exemplifies that the identification of a single cancer-predisposing mutation within the index patient may not be sufficient in some circumstances. Ideally, all family members affected by breast or ovarian tumor disease have to be subjected to the DNA testing, and failure to detect the mutation in any of them calls for the search of the second cancer-associated allele. PMID:19338681

  14. Mutations in Ran system affected telomere silencing in Saccharomyces cerevisiae

    SciTech Connect

    Hayashi, Naoyuki Kobayashi, Masahiko; Shimizu, Hiroko; Yamamoto, Ken-ichi; Murakami, Seishi; Nishimoto, Takeharu

    2007-11-23

    The Ran GTPase system regulates the direction and timing of several cellular events, such as nuclear-cytosolic transport, centrosome formation, and nuclear envelope assembly in telophase. To gain insight into the Ran system's involvement in chromatin formation, we investigated gene silencing at the telomere in several mutants of the budding yeast Saccharomyces cerevisiae, which had defects in genes involved in the Ran system. A mutation of the RanGAP gene, rna1-1, caused reduced silencing at the telomere, and partial disruption of the nuclear Ran binding factor, yrb2-{delta}2, increased this silencing. The reduced telomere silencing in rna1-1 cells was suppressed by a high dosage of the SIR3 gene or the SIT4 gene. Furthermore, hyperphosphorylated Sir3 protein accumulated in the rna1-1 mutant. These results suggest that RanGAP is required for the heterochromatin structure at the telomere in budding yeast.

  15. Symbiosis-mediated outbreaks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Symbiosis simply means "living together" and in its narrowest form can mean two species deriving mutual benefit from the association. Recent studies have made evident that insect associations with microorganisms can range the gamut from casual associations to obligate or context-dependent mutualisms...

  16. Survival through Symbiosis.

    ERIC Educational Resources Information Center

    Abdi, S. Wali

    1992-01-01

    Describes symbiosis and its significance in the day-to-day lives of plants and animals. Gives specific examples of mutualism, commensalism, and parasitism in the relationships among fungus and plant roots, animals and bacteria, birds and animals, fish, and predator and prey. (MDH)

  17. Parental age affects somatic mutation rates in the progeny of flowering plants.

    PubMed

    Singh, Amit Kumar; Bashir, Tufail; Sailer, Christian; Gurumoorthy, Viswanathan; Ramakrishnan, Anantha Maharasi; Dhanapal, Shanmuhapreya; Grossniklaus, Ueli; Baskar, Ramamurthy

    2015-05-01

    In humans, it is well known that the parental reproductive age has a strong influence on mutations transmitted to their progeny. Meiotic nondisjunction is known to increase in older mothers, and base substitutions tend to go up with paternal reproductive age. Hence, it is clear that the germinal mutation rates are a function of both maternal and paternal ages in humans. In contrast, it is unknown whether the parental reproductive age has an effect on somatic mutation rates in the progeny, because these are rare and difficult to detect. To address this question, we took advantage of the plant model system Arabidopsis (Arabidopsis thaliana), where mutation detector lines allow for an easy quantitation of somatic mutations, to test the effect of parental age on somatic mutation rates in the progeny. Although we found no significant effect of parental age on base substitutions, we found that frameshift mutations and transposition events increased in the progeny of older parents, an effect that is stronger through the maternal line. In contrast, intrachromosomal recombination events in the progeny decrease with the age of the parents in a parent-of-origin-dependent manner. Our results clearly show that parental reproductive age affects somatic mutation rates in the progeny and, thus, that some form of age-dependent information, which affects the frequency of double-strand breaks and possibly other processes involved in maintaining genome integrity, is transmitted through the gametes. PMID:25810093

  18. Diaphanous gene mutation affects spiral cleavage and chirality in snails

    PubMed Central

    Kuroda, Reiko; Fujikura, Kohei; Abe, Masanori; Hosoiri, Yuji; Asakawa, Shuichi; Shimizu, Miho; Umeda, Shin; Ichikawa, Futaba; Takahashi, Hiromi

    2016-01-01

    L-R (left and right) symmetry breaking during embryogenesis and the establishment of asymmetric body plan are key issues in developmental biology, but the onset including the handedness-determining gene locus still remains unknown. Using pure dextral (DD) and sinistral (dd) strains of the pond snail Lymnaea stagnalis as well as its F2 through to F10 backcrossed lines, the single handedness-determining-gene locus was mapped by genetic linkage analysis, BAC cloning and chromosome walking. We have identified the actin-related diaphanous gene Lsdia1 as the strongest candidate. Although the cDNA and derived amino acid sequences of the tandemly duplicated Lsdia1 and Lsdia2 genes are very similar, we could discriminate the two genes/proteins in our molecular biology experiments. The Lsdia1 gene of the sinistral strain carries a frameshift mutation that abrogates full-length LsDia1 protein expression. In the dextral strain, it is already translated prior to oviposition. Expression of Lsdia1 (only in the dextral strain) and Lsdia2 (in both chirality) decreases after the 1-cell stage, with no asymmetric localization throughout. The evolutionary relationships among body handedness, SD/SI (spiral deformation/spindle inclination) at the third cleavage, and expression of diaphanous proteins are discussed in comparison with three other pond snails (L. peregra, Physa acuta and Indoplanorbis exustus). PMID:27708420

  19. Amber mutation affecting the length of Escherichia coli cells.

    PubMed Central

    Martínez-Salas, E; Vicente, M

    1980-01-01

    An amber mutation in a newly found gene (wee) of Escherichia coli has been isolated from strain OV-2, which harbors a temperature-sensitive suppressor. At 42 degrees C cells of the mutant, OV-25, increased in mass and deoxyribonucleic acid content and divided at normal rates, compared with the wild type under the same growth conditions. Total cell length increased under the restrictive conditions, although at a slightly lower rate. Values of mean cell length and cell volume, contrary to what would be expected from the increment in the rate of increase in particles, mass, and deoxyribonucleic acid, became at 42 degrees C smaller than those found in the wild type. A parallel increase in protein content per length and cell density and a loss of viability were found to occur after four generations at the restrictive temperature. The behavior of strain OV-25 in the absence of the wee gene product could be interpreted in terms of either a faulty regulation of the elongation processes or their abnormal coordination with the cell cycle. The genetic location of the wee gene has been found to be at 83.5 min on the E. coli genetic map. PMID:7000749

  20. Mutations along the hypothalamic-pituitary-gonadal axis affecting male reproduction.

    PubMed

    Huhtaniemi, Ilpo; Alevizaki, Maria

    2007-12-01

    Disorders in male reproductive function are caused by mutations of key genes at all levels of the hypothalamic-pituitary- testicular axis. They may affect the ontogeny and function of the hypothalamic centres governing gonadotrophin synthesis and secretion, the development of the anterior pituitary gland, the production of gonadotrophins and the function of their receptor genes, and finally the genes responsible for testicular hormone production and gametogenesis. This review focuses on mutations that affect the synthesis and secretion of hypothalamic gonadotrophin-releasing hormone, pituitary follicle-stimulating hormone and luteinising hormone, as well as their testicular receptors, thus covering a selected group of genetic causes of hypo- and hypergonadotrophic male hypogonadism.

  1. Mutations Affecting Ty-Mediated Expression of the HIS4 Gene of SACCHAROMYCES CEREVISIAE

    PubMed Central

    Winston, Fred; Chaleff, Deborah T.; Valent, Barbara; Fink, Gerald R.

    1984-01-01

    We have identified mutations in seven unlinked genes (SPT genes) that affect the phenotypes of Ty and δ insertion mutations in the 5' noncoding region of the HIS4 gene of S. cerevisiae. Spt mutants were selected for suppression of his4-912δ, a solo δ derivative of Ty912. Other Ty and δ insertions at HIS4 are suppressed by mutations in some but not all of the SPT genes. Only spt4 suppresses a non-Ty insertion at HIS4. In addition to their effects on Ty and δ insertions, mutations in several SPT genes show defects in general cellular functions—mating. DNA repair and growth. PMID:6329902

  2. Suppressors of Mutations in the rII Gene of Bacteriophage T4 Affect Promoter Utilization

    PubMed Central

    Hall, Dwight H.; Snyder, Ronald D.

    1981-01-01

    Homyk, Rodriguez and Weil (1976) have described T4 mutants, called sip, that partially suppress the inability of T4rII mutants to grow in λ lysogens. We have found that mutants sip1 and sip2 are resistant to folate analogs and overproduce FH2 reductase. The results of recombination and complementation studies indicate that sip mutations are in the mot gene. Like other mot mutations (Mattson, Richardson and Goodin 1974; Chace and Hall 1975; Sauerbier, Hercules and Hall 1976), the sip2 mutation affects the expression of many genes and appears to affect promoter utilization. The mot gene function is not required for T4 growth on most hosts, but we have found that it is required for good growth on E. coli CTr5X. Homyk, Rodriguez and Weil (1976) also described L mutations that reverse the effects of sip mutations. L2 decreases the folate analog resistance and the inability of sip2 to grow on CTr5X. L2 itself is partially resistant to a folate analog, and appears to reverse the effects of sip2 on gene expression. These results suggest that L2 affects another regulatory gene related to the mot gene. PMID:7262547

  3. Scanning for MODY5 gene mutations in Chinese early onset or multiple affected diabetes pedigrees.

    PubMed

    Wang, C; Fang, Q; Zhang, R; Lin, X; Xiang, K

    2004-12-01

    Mutation of HNF-1beta gene has been reported in early onset diabetes or MODY families and this gene has been defined as MODY5 gene. The aim of our study was to examine whether HNF-1beta mutation contribute to early onset or multiple affected diabetes pedigrees in Chinese. Molecular scanning of HNF-1beta gene promoter region, nine exons and flanking introns was performed in 154 unrelated probands from early onset and multiple affected diabetes Chinese pedigrees. The family members of probands with mutations or variants and 58 nondiabetics were also examined. Clinical examinations of renal morphology, renal function and beta-cell function were performed in the HNF-1beta gene mutation carriers and family members. Mutation of HNF-1beta gene causing the substitution S36F was found in two subjects of an early onset diabetic family. One carrier has early onset diabetes, renal function impairment and renal cyst, while the other has impaired glucose tolerance only. This is the first case of MODY5 gene mutation diabetes found in the Chinese. Three HNF-1beta variants were identified and no significant differences in allele frequencies for these variants were detected between the nondiabetic and diabetic groups. Nucleotide 66 of intron 8 of HNF-1beta gene was G in the Chinese population rather than A as noted in the GenBank sequence. These results suggest that HNF-1beta gene mutations may be associated with nondiabetic renal dysfunction and diabetes in Chinese, but they are responsible for only a small percentage of early onset or multiple affected diabetes pedigrees including MODY. PMID:15660195

  4. Epidemiology of Van der Woude syndrome from mutational analyses in affected patients from Pakistan.

    PubMed

    Malik, S; Kakar, N; Hasnain, S; Ahmad, J; Wilcox, E R; Naz, S

    2010-09-01

    Mutations in IRF6 cause Van der Woude syndrome (VWS), one of the most common syndromes associated with cleft lip (CL) with or without cleft palate (CP). The presence of pits on the lower lip of patients is the most characteristic feature of the syndrome. We have identified three novel and seven previously reported IRF6 mutations in 12 of 16 unrelated families segregating VWS from Pakistan. The three newly identified mutations include a frameshift (c.568delG) and two missense mutations c.295G>A (p.G99S) and c.1219T>C (p.S407P). Recent functional studies on IRF6 and the three-dimensional structure of IRF5 carboxy (C) terminus, a protein encoded by a paralog of IRF6, shed light on the p.S407P substitution. Additionally, the identification of the same mutations responsible for VWS in Pakistan, as reported in other global populations worldwide, marks these residues as mutational hotspots and indicates their essential role in structural stability or function of IRF6. This is the first study of VWS in Pakistan and we estimate that 1 in 100 patients with CL with or without CP (CL/P) are affected in the Pakistani population predominantly from the Punjab area. PMID:20184620

  5. Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism.

    PubMed

    Sartorato, Paola; Lapeyraque, Anne-Laure; Armanini, Decio; Kuhnle, Ursula; Khaldi, Yasmina; Salomon, Rémi; Abadie, Véronique; Di Battista, Eliana; Naselli, Arturo; Racine, Alain; Bosio, Maurizio; Caprio, Massimiliano; Poulet-Young, Véronique; Chabrolle, Jean-Pierre; Niaudet, Patrick; De Gennes, Christiane; Lecornec, Marie-Hélène; Poisson, Elodie; Fusco, Anna Maria; Loli, Paola; Lombès, Marc; Zennaro, Maria-Christina

    2003-06-01

    We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease. PMID:12788847

  6. Different inactivating mutations of the mineralocorticoid receptor in fourteen families affected by type I pseudohypoaldosteronism.

    PubMed

    Sartorato, Paola; Lapeyraque, Anne-Laure; Armanini, Decio; Kuhnle, Ursula; Khaldi, Yasmina; Salomon, Rémi; Abadie, Véronique; Di Battista, Eliana; Naselli, Arturo; Racine, Alain; Bosio, Maurizio; Caprio, Massimiliano; Poulet-Young, Véronique; Chabrolle, Jean-Pierre; Niaudet, Patrick; De Gennes, Christiane; Lecornec, Marie-Hélène; Poisson, Elodie; Fusco, Anna Maria; Loli, Paola; Lombès, Marc; Zennaro, Maria-Christina

    2003-06-01

    We have analyzed the human mineralocorticoid receptor (hMR) gene in 14 families with autosomal dominant or sporadic pseudohypoaldosteronism (PHA1), a rare form of mineralocorticoid resistance characterized by neonatal renal salt wasting and failure to thrive. Six heterozygous mutations were detected. Two frameshift mutations in exon 2 (insT1354, del8bp537) and one nonsense mutation in exon 4 (C2157A, Cys645stop) generate truncated proteins due to premature stop codons. Three missense mutations (G633R, Q776R, L979P) differently affect hMR function. The DNA binding domain mutant R633 exhibits reduced maximal transactivation, although its binding characteristics and ED(50) of transactivation are comparable with wild-type hMR. Ligand binding domain mutants R776 and P979 present reduced or absent aldosterone binding, respectively, which is associated with reduced or absent ligand-dependent transactivation capacity. Finally, P979 possesses a transdominant negative effect on wild-type hMR activity, whereas mutations G633R and Q776R probably result in haploinsufficiency in PHA1 patients. We conclude that hMR mutations are a common feature of autosomal dominant PHA1, being found in 70% of our familial cases. Their absence in some families underscores the importance of an extensive investigation of the hMR gene and the role of precise diagnostic procedures to allow for identification of other genes potentially involved in the disease.

  7. A novel mutation in TFL1 homolog affecting determinacy in cowpea (Vigna unguiculata).

    PubMed

    Dhanasekar, P; Reddy, K S

    2015-02-01

    Mutations in the widely conserved Arabidopsis Terminal Flower 1 (TFL1) gene and its homologs have been demonstrated to result in determinacy across genera, the knowledge of which is lacking in cowpea. Understanding the molecular events leading to determinacy of apical meristems could hasten development of cowpea varieties with suitable ideotypes. Isolation and characterization of a novel mutation in cowpea TFL1 homolog (VuTFL1) affecting determinacy is reported here for the first time. Cowpea TFL1 homolog was amplified using primers designed based on conserved sequences in related genera and sequence variation was analysed in three gamma ray-induced determinate mutants, their indeterminate parent "EC394763" and two indeterminate varieties. The analyses of sequence variation exposed a novel SNP distinguishing the determinate mutants from the indeterminate types. The non-synonymous point mutation in exon 4 at position 1,176 resulted from transversion of cytosine (C) to adenine (A) leading to an amino acid change (Pro-136 to His) in determinate mutants. The effect of the mutation on protein function and stability was predicted to be detrimental using different bioinformatics/computational tools. The functionally significant novel substitution mutation is hypothesized to affect determinacy in the cowpea mutants. Development of suitable regeneration protocols in this hitherto recalcitrant crop and subsequent complementation assay in mutants or over-expressing assay in parents could decisively conclude the role of the SNP in regulating determinacy in these cowpea mutants. PMID:25146839

  8. A novel mutation in TFL1 homolog affecting determinacy in cowpea (Vigna unguiculata).

    PubMed

    Dhanasekar, P; Reddy, K S

    2015-02-01

    Mutations in the widely conserved Arabidopsis Terminal Flower 1 (TFL1) gene and its homologs have been demonstrated to result in determinacy across genera, the knowledge of which is lacking in cowpea. Understanding the molecular events leading to determinacy of apical meristems could hasten development of cowpea varieties with suitable ideotypes. Isolation and characterization of a novel mutation in cowpea TFL1 homolog (VuTFL1) affecting determinacy is reported here for the first time. Cowpea TFL1 homolog was amplified using primers designed based on conserved sequences in related genera and sequence variation was analysed in three gamma ray-induced determinate mutants, their indeterminate parent "EC394763" and two indeterminate varieties. The analyses of sequence variation exposed a novel SNP distinguishing the determinate mutants from the indeterminate types. The non-synonymous point mutation in exon 4 at position 1,176 resulted from transversion of cytosine (C) to adenine (A) leading to an amino acid change (Pro-136 to His) in determinate mutants. The effect of the mutation on protein function and stability was predicted to be detrimental using different bioinformatics/computational tools. The functionally significant novel substitution mutation is hypothesized to affect determinacy in the cowpea mutants. Development of suitable regeneration protocols in this hitherto recalcitrant crop and subsequent complementation assay in mutants or over-expressing assay in parents could decisively conclude the role of the SNP in regulating determinacy in these cowpea mutants.

  9. Novel mutations affecting LRP5 splicing in patients with osteoporosis-pseudoglioma syndrome (OPPG)

    PubMed Central

    Laine, C M; Chung, B D; Susic, M; Prescott, T; Semler, O; Fiskerstrand, T; D'Eufemia, P; Castori, M; Pekkinen, M; Sochett, E; Cole, W G; Netzer, C; Mäkitie, O

    2011-01-01

    Osteoporosis-pseudoglioma sydrome (OPPG) is an autosomal recessive disorder with early-onset severe osteoporosis and blindness, caused by biallelic loss-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. Heterozygous carriers exhibit a milder bone phenotype. Only a few splice mutations in LRP5 have been published. We present clinical and genetic data for four patients with novel LRP5 mutations, three of which affect splicing. Patients were evaluated clinically and by radiography and bone densitometry. Genetic screening of LRP5 was performed on the basis of the clinical diagnosis of OPPG. Splice aberrances were confirmed by cDNA sequencing or exon trapping. The effect of one splice mutation on LRP5 protein function was studied. A novel splice-site mutation c.1584+4A>T abolished the donor splice site of exon 7 and activated a cryptic splice site, which led to an in-frame insertion of 21 amino acids (p.E528_V529ins21). Functional studies revealed severely impaired signal transduction presumably caused by defective intracellular transport of the mutated receptor. Exon trapping was used on two samples to confirm that splice-site mutations c.4112-2A>G and c.1015+1G>T caused splicing-out of exons 20 and 5, respectively. One patient carried a homozygous deletion of exon 4 causing the loss of exons 4 and 5, as demonstrated by cDNA analysis. Our results broaden the spectrum of mutations in LRP5 and provide the first functional data on splice aberrations. PMID:21407258

  10. Water Collective Dynamics in Whole Photosynthetic Green Algae as Affected by Protein Single Mutation.

    PubMed

    Russo, Daniela; Rea, Giuseppina; Lambreva, Maya D; Haertlein, Michael; Moulin, Martine; De Francesco, Alessio; Campi, Gaetano

    2016-07-01

    In the context of the importance of water molecules for protein function/dynamics relationship, the role of water collective dynamics in Chlamydomonas green algae carrying both native and mutated photosynthetic proteins has been investigated by neutron Brillouin scattering spectroscopy. Results show that single point genetic mutation may notably affect collective density fluctuations in hydrating water providing important insight on the transmission of information possibly correlated to biological functionality. In particular, we highlight that the damping factor of the excitations is larger in the native compared to the mutant algae as a signature of a different plasticity and structure of the hydrogen bond network. PMID:27300078

  11. Determinant factors of industrial symbiosis: greening Pasir Gudang industrial park

    NASA Astrophysics Data System (ADS)

    Teh, B. T.; Ho, C. S.; Matsuoka, Y.; Chau, L. W.; Gomi, K.

    2014-02-01

    Green industry has been identified as an important element in attaining greater sustainability. It calls for harmonizing robust economic growth with environment protection. Industries, particularly in developing and transitional nations such as Malaysia, are in need of a reform. Many experts and international organizations suggest the concept of industrial symbiosis. Mainly, there are successful cases of industrial symbiosis practices around the world. However, there are numerous cases of failure too. As industrial symbiosis is an emerging new approach, with a short history of two decades, a lot of researches are generally focused on narrow context and technical details. There is a lack of concerted efforts to look into the drivers and barriers of industrial symbiosis across different cases. This paper aims to examine the factors influencing the development of industrial symbiosis from various countries to supports such networks to evolve in Pasir Gudang. The findings show institution, law and regulation, finance, awareness and capacity building, technology, research and development, information, collaboration, market, geography proximity, environmental issues and industry structure affect the formation of industrial symbiosis.

  12. A Peptidoglycan-Remodeling Enzyme Is Critical for Bacteroid Differentiation in Bradyrhizobium spp. During Legume Symbiosis.

    PubMed

    Gully, Djamel; Gargani, Daniel; Bonaldi, Katia; Grangeteau, Cédric; Chaintreuil, Clémence; Fardoux, Joël; Nguyen, Phuong; Marchetti, Roberta; Nouwen, Nico; Molinaro, Antonio; Mergaert, Peter; Giraud, Eric

    2016-06-01

    In response to the presence of compatible rhizobium bacteria, legumes form symbiotic organs called nodules on their roots. These nodules house nitrogen-fixing bacteroids that are a differentiated form of the rhizobium bacteria. In some legumes, the bacteroid differentiation comprises a dramatic cell enlargement, polyploidization, and other morphological changes. Here, we demonstrate that a peptidoglycan-modifying enzyme in Bradyrhizobium strains, a DD-carboxypeptidase that contains a peptidoglycan-binding SPOR domain, is essential for normal bacteroid differentiation in Aeschynomene species. The corresponding mutants formed bacteroids that are malformed and hypertrophied. However, in soybean, a plant that does not induce morphological differentiation of its symbiont, the mutation does not affect the bacteroids. Remarkably, the mutation also leads to necrosis in a large fraction of the Aeschynomene nodules, indicating that a normally formed peptidoglycan layer is essential for avoiding the induction of plant immune responses by the invading bacteria. In addition to exopolysaccharides, capsular polysaccharides, and lipopolysaccharides, whose role during symbiosis is well defined, our work demonstrates an essential role in symbiosis for yet another rhizobial envelope component, the peptidoglycan layer.

  13. Novel Mutations Affecting a Signaling Component for Chemotaxis of Escherichia coli

    PubMed Central

    Parkinson, John S.

    1980-01-01

    The genetic relationship between tsr and cheD mutations, which affect chemotactic ability and map at approximately 99 min on the Escherichia coli chromosome, was investigated. Mutants defective in tsr function typically exhibited wild-type swimming patterns, but were unable to carry out chemotactic responses to a number of attractant and repellent chemicals. In contrast, cheD mutants swam smoothly, with few spontaneous directional changes, and were generally nonchemotactic. In complementation tests, cheD mutations, unlike tsr, proved to be dominant to wild type, suggesting that the cheD defect might be due to an active inhibitor of chemotaxis. Mutations that inactivated the putative inhibitor were obtained by selecting for restoration of chemotactic ability or for loss of cheD dominance. The resultant double mutants were shown to carry the original cheD mutation and a second tightly linked mutation, some of which exhibited nonsense or temperature-sensitive phenotypes, implying that they had occurred in a structural gene for a protein. All such double mutants behaved like typical tsr mutants in all other respects, including complementation pattern, swimming behavior, and chemotactic ability. These findings implied that either overproduction of tsr product or synthesis of an aberrant tsr product was responsible for the chemotaxis defect of cheD strains. Such mutants should be useful in analyzing the role of the tsr product in chemotactic responses. Images PMID:6991496

  14. Mutations affecting synaptic levels of neurexin-1β in autism and mental retardation.

    PubMed

    Camacho-Garcia, Rafael J; Planelles, Maria Inmaculada; Margalef, Mar; Pecero, Maria L; Martínez-Leal, Rafael; Aguilera, Francisco; Vilella, Elisabet; Martinez-Mir, Amalia; Scholl, Francisco G

    2012-07-01

    The identification of mutations in genes encoding proteins of the synaptic neurexin-neuroligin pathway in different neurodevelopmental disorders, including autism and mental retardation, has suggested the presence of a shared underlying mechanism. A few mutations have been described so far and for most of them the biological consequences are unknown. To further explore the role of the NRXN1β gene in neurodevelopmental disorders, we have sequenced the coding exons of the gene in 86 cases with autism and mental retardation and 200 controls and performed expression analysis of DNA variants identified in patients. We report the identification of four novel independent mutations that affect nearby positions in two regions of the gene/protein: i) sequences important for protein translation initiation, c.-3G>T within the Kozak sequence, and c.3G>T (p.Met1), at the initiation codon; and ii) the juxtamembrane region of the extracellular domain, p.Arg375Gln and p.Gly378Ser. These mutations cosegregate with different psychiatric disorders other than autism and mental retardation, such as psychosis and attention-deficit/hyperactivity disorder. We provide experimental evidence for the use of an alternative translation initiation codon for c.-3G>T and p.Met1 mutations and reduced synaptic levels of neurexin-1β protein resulting from p.Met1 and p.Arg375Gln. The data reported here support a role for synaptic defects of neurexin-1β in neurodevelopmental disorders.

  15. Analysis of fluG mutations that affect light-dependent conidiation in Aspergillus nidulans.

    PubMed Central

    Yager, L N; Lee, H O; Nagle, D L; Zimmerman, J E

    1998-01-01

    Conidiation in Aspergillus nidulans is induced by exposure to red light but can also be induced by blue light in certain mutant strains. We have isolated a mutation in the fluG gene that abolishes responsiveness to red light but does not affect the response to blue light. It has been shown that the veA1 (velvet) mutation allows conidiation to occur in the absence of light. We have identified three other fluG mutations that suppress the veA1 phenotype; these double mutants do not conidiate in the dark. The mutations described here define two new phenotypic classes of fluG alleles that display abnormal responses to light. We have characterized these mutations with respect to their molecular identity and to their effect on fluG transcription. Although it has been shown that fluG is required for the synthesis of an extracellular factor that directs conidiation, we do not detect this factor under conditions that promote conidiation in the veA1 suppressors. Furthermore, extracellular rescue is not observed in fluG deletion strains containing the wild-type veA allele. We propose that a genetic interaction between fluG and veA influences the production of the extracellular signal and regulates the initiation of conidiation. PMID:9691036

  16. A novel SMARCAL1 missense mutation that affects splicing in a severely affected Schimke immunoosseous dysplasia patient.

    PubMed

    Barraza-García, Jimena; Rivera-Pedroza, Carlos I; Belinchón, Alberta; Fernández-Camblor, Carlota; Valenciano-Fuente, Blanca; Lapunzina, Pablo; Heath, Karen E

    2016-08-01

    Schimke immunoosseous dysplasia (SIOD) is an autosomal recessive disease characterized by skeletal dysplasia, focal segmental glomerulosclerosis, renal failure and immunodeficiency. In this work, we report the molecular studies undertaken in a severely affected SIOD patient that died at six years old due to nephropathy. The patient was screened for mutations using a targeted skeletal dysplasias panel. A homozygous novel missense mutation was identified, c.1615C > G (p.[Leu539Val]) that was predicted as mildly pathogenic by in silico pathogenicity prediction tools. However, splicing prediction software suggested that this variant may create a new splicing donor site in exon 9, which was subsequently confirmed using a minigene assay in HEK293 cells. Thus, the splicing alteration, c.1615C > G; r.1615c > g, 1615_1644del; (p.[Leu539_Ile548del]), results in the loss of 10 amino acids of the HARP-ATPase catalytic domain and the RPA-binding domain. Several studies have demonstrated a weak genotype-phenotype correlation among such patients. Thus, the molecular characterization has helped us to understand why a predicted weakly pathogenic missense mutation results in severe SIOD and should be considered in similar scenarios. PMID:27282802

  17. Progranulin Mutations Affects Brain Oscillatory Activity in Fronto-Temporal Dementia

    PubMed Central

    Moretti, Davide V.; Benussi, Luisa; Fostinelli, Silvia; Ciani, Miriam; Binetti, Giuliano; Ghidoni, Roberta

    2016-01-01

    Background: Mild cognitive impairment (MCI) is a clinical stage indicating a prodromal phase of dementia. This practical concept could be used also for fronto-temporal dementia (FTD). Progranulin (PGRN) has been recently recognized as a useful diagnostic biomarker for fronto-temporal lobe degeneration (FTLD) due to GRN null mutations. Electroencephalography (EEG) is a reliable tool in detecting brain networks changes. The working hypothesis of the present study is that EEG oscillations could detect different modifications among FTLD stages (FTD-MCI versus overt FTD) as well as differences between GRN mutation carriers versus non-carriers in patients with overt FTD. Materials and Methods: EEG in all patients and PGRN dosage in patients with a clear FTD were detected. The cognitive state has been investigated through mini mental state examination (MMSE). Results: MCI-FTD showed a significant lower spectral power in both alpha and theta oscillations as compared to overt FTD. GRN mutations carriers affected by FTLD show an increase in high alpha and decrease in theta oscillations as compared to non-carriers. Conclusion: EEG frequency rhythms are sensible to different stage of FTD and could detect changes in brain oscillatory activity affected by GRN mutations. PMID:26973510

  18. Mutations affecting extracellular protease production in the filamentous fungus Aspergillus nidulans.

    PubMed

    Katz, M E; Flynn, P K; vanKuyk, P A; Cheetham, B F

    1996-04-10

    The extracellular proteases of Aspergillus nidulans are known to be regulated by carbon, nitrogen and sulphur metabolite repression. In this study, a mutant with reduced levels of extracellular protease was isolated by screening for loss of halo production on milk plates. Genetic analysis of the mutant showed that it contains a single, recessive mutation, in a gene which we have designated xprE, located on chromosome VI. The xprE1 mutation affected the production of extracellular proteases in response to carbon, nitrogen and, to a lesser extent, sulphur limitation. Three reversion mutations, xprF1, xprF2 and xprG1, which suppress xprE1, were characterised. Both xprF and xprG map to chromosome VII but the two genes are unlinked. The xprF1, xprF2 and xprG1 mutants showed high levels of milk-clearing activity on medium containing milk as a carbon source but reduced growth on a number of nitrogen sources. Evidence is presented that the xprE1 and xprG1 mutations alter expression of more than one protease and affect levels of alkaline protease gene mRNA.

  19. Identification of Regulatory Mutations in SERPINC1 Affecting Vitamin D Response Elements Associated with Antithrombin Deficiency

    PubMed Central

    Toderici, Mara; de la Morena-Barrio, María Eugenia; Padilla, José; Miñano, Antonia; Antón, Ana Isabel; Iniesta, Juan Antonio; Herranz, María Teresa; Fernández, Nuria; Vicente, Vicente; Corral, Javier

    2016-01-01

    Antithrombin is a crucial anticoagulant serpin whose even moderate deficiency significantly increases the risk of thrombosis. Most cases with antithrombin deficiency carried genetic defects affecting exons or flanking regions of SERPINC1.We aimed to identify regulatory mutations inSERPINC1 through sequencing the promoter, intron 1 and 2 of this gene in 23 patients with antithrombin deficiency but without known genetic defects. Three cases with moderate antithrombin deficiency (63–78%) carried potential regulatory mutations. One located 200 bp before the initiation ATG and two in intron 1. These mutations disrupted two out of five potential vitamin D receptor elements (VDRE) identified in SERPINC1 with different software. One genetic defect, c.42-1060_-1057dupTTGA, was a new low prevalent polymorphism (MAF: 0.01) with functional consequences on plasma antithrombin levels. The relevance of the vitamin D pathway on the regulation of SERPINC1 was confirmed in a cell model. Incubation of HepG2 with paricalcitol, a vitamin D analog, increased dose-dependently the levels of SERPINC1transcripts and antithrombin released to the conditioned medium. This study shows further evidence of the transcriptional regulation of SERPINC1 by vitamin D and first describes the functional and pathological relevance of mutations affecting VDRE of this gene. Our study opens new perspectives in the search of new genetic defects involved in antithrombin deficiency and the risk of thrombosis as well as in the design of new antithrombotic treatments. PMID:27003919

  20. Distinct splicing signatures affect converged pathways in myelodysplastic syndrome patients carrying mutations in different splicing regulators.

    PubMed

    Qiu, Jinsong; Zhou, Bing; Thol, Felicitas; Zhou, Yu; Chen, Liang; Shao, Changwei; DeBoever, Christopher; Hou, Jiayi; Li, Hairi; Chaturvedi, Anuhar; Ganser, Arnold; Bejar, Rafael; Zhang, Dong-Er; Fu, Xiang-Dong; Heuser, Michael

    2016-10-01

    Myelodysplastic syndromes (MDS) are heterogeneous myeloid disorders with prevalent mutations in several splicing factors, but the splicing programs linked to specific mutations or MDS in general remain to be systematically defined. We applied RASL-seq, a sensitive and cost-effective platform, to interrogate 5502 annotated splicing events in 169 samples from MDS patients or healthy individuals. We found that splicing signatures associated with normal hematopoietic lineages are largely related to cell signaling and differentiation programs, whereas MDS-linked signatures are primarily involved in cell cycle control and DNA damage responses. Despite the shared roles of affected splicing factors in the 3' splice site definition, mutations in U2AF1, SRSF2, and SF3B1 affect divergent splicing programs, and interestingly, the affected genes fall into converging cancer-related pathways. A risk score derived from 11 splicing events appears to be independently associated with an MDS prognosis and AML transformation, suggesting potential clinical relevance of altered splicing patterns in MDS. PMID:27492256

  1. Mutations in the putative calcium-binding domain of polyomavirus VP1 affect capsid assembly

    NASA Technical Reports Server (NTRS)

    Haynes, J. I. 2nd; Chang, D.; Consigli, R. A.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    Calcium ions appear to play a major role in maintaining the structural integrity of the polyomavirus and are likely involved in the processes of viral uncoating and assembly. Previous studies demonstrated that a VP1 fragment extending from Pro-232 to Asp-364 has calcium-binding capabilities. This fragment contains an amino acid stretch from Asp-266 to Glu-277 which is quite similar in sequence to the amino acids that make up the calcium-binding EF hand structures found in many proteins. To assess the contribution of this domain to polyomavirus structural integrity, the effects of mutations in this region were examined by transfecting mutated viral DNA into susceptible cells. Immunofluorescence studies indicated that although viral protein synthesis occurred normally, infective viral progeny were not produced in cells transfected with polyomavirus genomes encoding either a VP1 molecule lacking amino acids Thr-262 through Gly-276 or a VP1 molecule containing a mutation of Asp-266 to Ala. VP1 molecules containing the deletion mutation were unable to bind 45Ca in an in vitro assay. Upon expression in Escherichia coli and purification by immunoaffinity chromatography, wild-type VP1 was isolated as pentameric, capsomere-like structures which could be induced to form capsid-like structures upon addition of CaCl2, consistent with previous studies. However, although VP1 containing the point mutation was isolated as pentamers which were indistinguishable from wild-type VP1 pentamers, addition of CaCl2 did not result in their assembly into capsid-like structures. Immunogold labeling and electron microscopy studies of transfected mammalian cells provided in vivo evidence that a mutation in this region affects the process of viral assembly.

  2. Mutations in the human adenosine deaminase gene that affect protein structure and RNA splicing

    SciTech Connect

    Akeson, A.L.; Wiginton, D.A.; States, C.J.; Perme, C.M.; Dusing, M.R.; Hutton, J.J.

    1987-08-01

    Adenosine deaminase deficiency is one cause of the genetic disease severe combined immunodeficiency. To identify mutations responsible for ADA deficiency, the authors synthesized cDNAs to ADA mRNAs from two cell lines, GM2756 and GM2825A, derived from ADA-deficient immunodeficient patients. Sequence analysis of GM2756 cDNA clones revealed a different point mutation in each allele that causes amino acid changes of alanine to valine and arginine to histidine. One allele of GM2825A also has a point mutation that causes an alanine to valine substitution. The other allele of GM2825A was found to produce an mRNA in which exon 4 had been spliced out but had no other detrimental mutations. S1 nuclease mapping of GM2825A mRNA showed equal abundance of the full-length ADA mRNA and the ADA mRNA that was missing exon 4. Several of the ADA cDNA clones extended 5' of the major initiation start site, indicating multiple start sites for ADA transcription. The point mutations in GM2756 and GM2825A and the absence of exon 4 in GM2825A appear to be directly responsible for the ADA deficiency. Comparison of a number of normal and mutant ADA cDNA sequences showed a number of changes in the third base of codons. These change do not affect the amino acid sequence. Analyses of ADA cDNAs from different cell lines detected aberrant RNA species that either included intron 7 or excluded exon 7. Their presence is a result of aberrant splicing of pre-mRNAs and is not related to mutations that cause ADA deficiency.

  3. Symbiosis-related pea genes modulate fungal and plant gene expression during the arbuscule stage of mycorrhiza with Glomus intraradices.

    PubMed

    Kuznetsova, Elena; Seddas-Dozolme, Pascale M A; Arnould, Christine; Tollot, Marie; van Tuinen, Diederik; Borisov, Alexey; Gianinazzi, Silvio; Gianinazzi-Pearson, Vivienne

    2010-08-01

    The arbuscular mycorrhiza association results from a successful interaction between genomes of the plant and fungal symbiotic partners. In this study, we analyzed the effect of inactivation of late-stage symbiosis-related pea genes on symbiosis-associated fungal and plant molecular responses in order to gain insight into their role in the functional mycorrhizal association. The expression of a subset of ten fungal and eight plant genes, previously reported to be activated during mycorrhiza development, was compared in Glomus intraradices-inoculated wild-type and isogenic genotypes of pea mutated for the PsSym36, PsSym33, and PsSym40 genes where arbuscule formation is inhibited or fungal turnover modulated, respectively. Microdissection was used to corroborate arbuscule-related fungal gene expression. Molecular responses varied between pea genotypes and with fungal development. Most of the fungal genes were downregulated when arbuscule formation was defective, and several were upregulated with more rapid fungal development. Some of the plant genes were also affected by inactivation of the PsSym36, PsSym33, and PsSym40 loci, but in a more time-dependent way during root colonization by G. intraradices. Results indicate a role of the late-stage symbiosis-related pea genes not only in mycorrhiza development but also in the symbiotic functioning of arbuscule-containing cells.

  4. Expanding genomics of mycorrhizal symbiosis

    DOE PAGES

    Kuo, Alan; Kohler, Annegret; Martin, Francis M.; Grigoriev, Igor V.

    2014-11-04

    The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant nutrition, soil health, and carbon cycling. The symbiosis evolved repeatedly and independently as multiple morphotypes [e.g., arbuscular mycorrhizae (AM), ectomycorrhizal (ECM)] in multiple fungal clades (e.g., phyla Glomeromycota, Ascomycota, Basidiomycota). The accessibility and cultivability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first three mycorrhizal fungal genomes, representing two morphotypes and three phyla. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolvemore » through loss of plant cell wall-degrading enzymes (PCWDEs) and expansion of lineage-specific gene families such as short secreted protein (SSP) effectors. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of families as in Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other two fungi, symbiosis can involve similar solutions as symbiosis-induced SSPs and loss of PCWDEs. The three genomes provide a solid base for addressing fundamental questions about the nature and role of a vital mutualism.« less

  5. Expanding genomics of mycorrhizal symbiosis

    SciTech Connect

    Kuo, Alan; Kohler, Annegret; Martin, Francis M.; Grigoriev, Igor V.

    2014-11-04

    The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant nutrition, soil health, and carbon cycling. The symbiosis evolved repeatedly and independently as multiple morphotypes [e.g., arbuscular mycorrhizae (AM), ectomycorrhizal (ECM)] in multiple fungal clades (e.g., phyla Glomeromycota, Ascomycota, Basidiomycota). The accessibility and cultivability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first three mycorrhizal fungal genomes, representing two morphotypes and three phyla. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolve through loss of plant cell wall-degrading enzymes (PCWDEs) and expansion of lineage-specific gene families such as short secreted protein (SSP) effectors. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of families as in Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other two fungi, symbiosis can involve similar solutions as symbiosis-induced SSPs and loss of PCWDEs. The three genomes provide a solid base for addressing fundamental questions about the nature and role of a vital mutualism.

  6. Expanding genomics of mycorrhizal symbiosis

    PubMed Central

    Kuo, Alan; Kohler, Annegret; Martin, Francis M.; Grigoriev, Igor V.

    2014-01-01

    The mycorrhizal symbiosis between soil fungi and plant roots is a ubiquitous mutualism that plays key roles in plant nutrition, soil health, and carbon cycling. The symbiosis evolved repeatedly and independently as multiple morphotypes [e.g., arbuscular mycorrhizae (AM), ectomycorrhizal (ECM)] in multiple fungal clades (e.g., phyla Glomeromycota, Ascomycota, Basidiomycota). The accessibility and cultivability of many mycorrhizal partners make them ideal models for symbiosis studies. Alongside molecular, physiological, and ecological investigations, sequencing led to the first three mycorrhizal fungal genomes, representing two morphotypes and three phyla. The genome of the ECM basidiomycete Laccaria bicolor showed that the mycorrhizal lifestyle can evolve through loss of plant cell wall-degrading enzymes (PCWDEs) and expansion of lineage-specific gene families such as short secreted protein (SSP) effectors. The genome of the ECM ascomycete Tuber melanosporum showed that the ECM type can evolve without expansion of families as in Laccaria, and thus a different set of symbiosis genes. The genome of the AM glomeromycete Rhizophagus irregularis showed that despite enormous phylogenetic distance and morphological difference from the other two fungi, symbiosis can involve similar solutions as symbiosis-induced SSPs and loss of PCWDEs. The three genomes provide a solid base for addressing fundamental questions about the nature and role of a vital mutualism. PMID:25408690

  7. Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia

    SciTech Connect

    Epstein, L.M.; Forney, J.D.

    1984-08-01

    A screening procedure was devised for the isolation of X-ray-induced mutations affecting the expression of the A immobilization antigen (i-antigen) in Paramecium tetraurelia. Two of the mutations isolated by this procedure proved to be in modifier genes. The two genes are unlinked to each other and unlinked to the structural A i-antigen gene. These are the first modifier genes identified in a Paramecium sp. that affect surface antigen expression. Another mutation was found to be a deletion of sequences just downstream from the A i-antigen gene. In cells carrying this mutation, the A i-antigen gene lies in close proximity to the end of a macronuclear chromosome. The expression of the A i-antigen is not affected in these cells, demonstrating that downstream sequences are not important for the regulation and expression of the A i-antigen gene. A stable cell line was also recovered which shows non-Mendelian inheritance of a macronuclear deletion of the A i-antigen gene. This mutant does not contain the gene in its macronucleus, but contains a complete copy of the gene in its micronucleus. In the cytoplasm of wild-type animals, the micronuclear gene is included in the developing macronucleus; in the cytoplasm of the mutant, the incorporation of the A i-antigen gene into the macronucleus is inhibited. This is the first evidence that a mechanism is available in ciliates to control the expression of a gene by regulating its incorporation into developing macronuclei.

  8. The Stability of G6PD Is Affected by Mutations with Different Clinical Phenotypes

    PubMed Central

    Gómez-Manzo, Saúl; Terrón-Hernández, Jessica; De la Mora-De la Mora, Ignacio; González-Valdez, Abigail; Marcial-Quino, Jaime; García-Torres, Itzhel; Vanoye-Carlo, America; López-Velázquez, Gabriel; Hernández-Alcántara, Gloria; Oria-Hernández, Jesús; Reyes-Vivas, Horacio; Enríquez-Flores, Sergio

    2014-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency worldwide, causing a wide spectrum of conditions with severity classified from the mildest (Class IV) to the most severe (Class I). To correlate mutation sites in the G6PD with the resulting phenotypes, we studied four naturally occurring G6PD variants: Yucatan, Nashville, Valladolid and Mexico City. For this purpose, we developed a successful over-expression method that constitutes an easier and more precise method for obtaining and characterizing these enzymes. The kcat (catalytic constant) of all the studied variants was lower than in the wild-type. The structural rigidity might be the cause and the most evident consequence of the mutations is their impact on protein stability and folding, as can be observed from the protein yield, the T50 (temperature where 50% of its original activity is retained) values, and differences on hydrophobic regions. The mutations corresponding to more severe phenotypes are related to the structural NADP+ region. This was clearly observed for the Classes III and II variants, which became more thermostable with increasing NADP+, whereas the Class I variants remained thermolabile. The mutations produce repulsive electric charges that, in the case of the Yucatan variant, promote increased disorder of the C-terminus and consequently affect the binding of NADP+, leading to enzyme instability. PMID:25407525

  9. Mutations in amyloid precursor protein affect its interactions with presenilin/γ-secretase

    PubMed Central

    Herl, Lauren; Thomas, Anne V.; Lill, Christina M.; Banks, Mary; Deng, Amy; Jones, Phill B.; Spoelgen, Robert; Hyman, Bradley T.; Berezovska, Oksana

    2009-01-01

    Alzheimer's disease is characterized by accumulation of toxic β-amyloid (Aβ) in the brain and neuronal death. Several mutations in presenilin (PS1) and β-amyloid precursor protein (APP) associate with an increased Aβ42/40 ratio. Aβ42, a highly fibrillogenic species, is believed to drive Aβ aggregation. Factors shifting γ-secretase cleavage of APP to produce Aβ42 are unclear. We investigate the molecular mechanism underlying altered Aβ42/40 ratios associated with APP mutations at codon 716 and 717. Using FRET-based fluorescence lifetime imaging to monitor APP-PS1 interactions, we show that I716F and V717I APP mutations increase the proportion of interacting molecules earlier in the secretory pathway, resulting in an increase in Aβ generation. A PS1 conformation assay reveals that, in the presence of mutant APP, PS1 adopts a conformation reminiscent of FAD-associated PS1 mutations, thus influencing APP binding to PS1/γ-secretase. Mutant APP affects both intracellular location and efficiency of APP-PS1 interactions, thereby changing the Aβ42/40 ratio. PMID:19281847

  10. Mutations in the clk-1 gene of Caenorhabditis elegans affect developmental and behavioral timing

    SciTech Connect

    Wong, A.; Boutis, P.; Hekimi, S.

    1995-03-01

    We have identified three allelic, maternal-effect mutations that affect developmental and behavioral timing in Caenorhabditis elegans. They result in a mean lengthening of embryonic and postembryonic development, the cell cycle period and life span, as well as the periods of the defecation, swimming and pumping cycles. These mutants also display a number of additional phenotypes related to timing. For example, the variability in the length of embryonic development is several times larger in the mutants than in the wild type, resulting in the occasional production of mutant embryos developing more rapidly than the most rapidly developing wild-type embryos. In addition, the duration of embryonic development of the mutants, but not of the wild type, depends on the temperature at which their parents were raised. Finally, individual variations in the severity of distinct mutant phenotypes are correlated in a counterintuitive way. For example, the animals with the shortest embryonic development have the longest defecation cycle and those with the longest embryonic development have the shortest defecation cycle. Most of the features affected by these mutations are believed to be controlled by biological clocks, and we therefore call the gene defined by these mutations clk-1, for {open_quotes}abnormal function of biological clocks.{close_quotes} 52 refs., 5 figs., 4 tabs.

  11. A New Mutation Affecting FRQ-Less Rhythms in the Circadian System of Neurospora crassa

    PubMed Central

    Li, Sanshu; Motavaze, Kamyar; Kafes, Elizabeth; Suntharalingam, Sujiththa; Lakin-Thomas, Patricia

    2011-01-01

    We are using the fungus Neurospora crassa as a model organism to study the circadian system of eukaryotes. Although the FRQ/WCC feedback loop is said to be central to the circadian system in Neurospora, rhythms can still be seen under many conditions in FRQ-less (frq knockout) strains. To try to identify components of the FRQ-less oscillator (FLO), we carried out a mutagenesis screen in a FRQ-less strain and selected colonies with altered conidiation (spore-formation) rhythms. A mutation we named UV90 affects rhythmicity in both FRQ-less and FRQ-sufficient strains. The UV90 mutation affects FRQ-less rhythms in two conditions: the free-running long-period rhythm in choline-depleted chol-1 strains becomes arrhythmic, and the heat-entrained rhythm in the frq10 knockout is severely altered. In a FRQ-sufficient background, the UV90 mutation causes damping of the free-running conidiation rhythm, reduction of the amplitude of the FRQ protein rhythm, and increased phase-resetting responses to both light and heat pulses, consistent with a decreased amplitude of the circadian oscillator. The UV90 mutation also has small but significant effects on the period of the conidiation rhythm and on growth rate. The wild-type UV90 gene product appears to be required for a functional FLO and for sustained, high-amplitude rhythms in FRQ-sufficient conditions. The UV90 gene product may therefore be a good candidate for a component of the FRQ-less oscillator. These results support a model of the Neurospora circadian system in which the FRQ/WCC feedback loop mutually interacts with a single FLO in an integrated circadian system. PMID:21731506

  12. Symbiosis, Empathy, Suicidal Behavior, and the Family.

    ERIC Educational Resources Information Center

    Richman, Joseph

    1978-01-01

    This paper discusses the theoretical concept of symbiosis, as described by Mahler and her co-workers, and its clinical applications in suicidal situations. Also, the practical implications of the concept of symbiosis for assessment and treatment are discussed (Author)

  13. Identification of quantitative trait loci affecting ectomycorrhizal symbiosis in an interspecific F1 poplar cross and differential expression of genes in ectomycorrhizas of the two parents: Populus deltoides and Populus trichocarpa

    SciTech Connect

    Labbe, Jessy L; Jorge, Veronique; Vion, Patrice; Marcais, Benoit; Bastien, Catherine; Tuskan, Gerald A; Martin, Francis; Le Tacon, F

    2011-01-01

    A Populus deltoides Populus trichocarpa F1 pedigree was analyzed for quantitative trait loci (QTLs) affecting ectomycorrhizal development and for microarray characterization of gene networks involved in this symbiosis. A 300 genotype progeny set was evaluated for its ability to form ectomycorrhiza with the basidiomycete Laccaria bicolor. The percentage of mycorrhizal root tips was determined on the root systems of all 300 progeny and their two parents. QTL analysis identified four significant QTLs, one on the P. deltoides and three on the P. trichocarpa genetic maps. These QTLs were aligned to the P. trichocarpa genome and each contained several megabases and encompass numerous genes. NimbleGen whole-genome microarray, using cDNA from RNA extracts of ectomycorrhizal root tips from the parental genotypes P. trichocarpa and P. deltoides, was used to narrow the candidate gene list. Among the 1,543 differentially expressed genes (p value 0.05; 5.0-fold change in transcript level) having different transcript levels in mycorrhiza of the two parents, 41 transcripts were located in the QTL intervals: 20 in Myc_d1, 14 in Myc_t1, and seven in Myc_t2, while no significant differences among transcripts were found in Myc_t3. Among these 41 transcripts, 25 were overrepresented in P. deltoides relative to P. trichocarpa; 16 were overrepresented in P. trichocarpa. The transcript showing the highest overrepresentation in P. trichocarpa mycorrhiza libraries compared to P. deltoides mycorrhiza codes for an ethylene-sensitive EREBP-4 protein which may repress defense mechanisms in P. trichocarpa while the highest overrepresented transcripts in P. deltoides code for proteins/genes typically associated with pathogen resistance.

  14. Human CalDAG-GEFI gene (RASGRP2) mutation affects platelet function and causes severe bleeding

    PubMed Central

    Canault, Matthias; Ghalloussi, Dorsaf; Grosdidier, Charlotte; Guinier, Marie; Perret, Claire; Chelghoum, Nadjim; Germain, Marine; Raslova, Hana; Peiretti, Franck; Morange, Pierre E.; Saut, Noemie; Pillois, Xavier; Nurden, Alan T.; Cambien, François; Pierres, Anne; van den Berg, Timo K.; Kuijpers, Taco W.; Tregouet, David-Alexandre

    2014-01-01

    The nature of an inherited platelet disorder was investigated in three siblings affected by severe bleeding. Using whole-exome sequencing, we identified the culprit mutation (cG742T) in the RAS guanyl-releasing protein-2 (RASGRP2) gene coding for calcium- and DAG-regulated guanine exchange factor-1 (CalDAG-GEFI). Platelets from individuals carrying the mutation present a reduced ability to activate Rap1 and to perform proper αIIbβ3 integrin inside-out signaling. Expression of CalDAG-GEFI mutant in HEK293T cells abolished Rap1 activation upon stimulation. Nevertheless, the PKC- and ADP-dependent pathways allow residual platelet activation in the absence of functional CalDAG-GEFI. The mutation impairs the platelet’s ability to form thrombi under flow and spread normally as a consequence of reduced Rac1 GTP-binding. Functional deficiencies were confined to platelets and megakaryocytes with no leukocyte alteration. This contrasts with the phenotype seen in type III leukocyte adhesion deficiency caused by the absence of kindlin-3. Heterozygous did not suffer from bleeding and have normal platelet aggregation; however, their platelets mimicked homozygous ones by failing to undergo normal adhesion under flow and spreading. Rescue experiments on cultured patient megakaryocytes corrected the functional deficiency after transfection with wild-type RASGRP2. Remarkably, the presence of a single normal allele is sufficient to prevent bleeding, making CalDAG-GEFI a novel and potentially safe therapeutic target to prevent thrombosis. PMID:24958846

  15. Mutations in the three largest subunits of yeast RNA polymerase II that affect enzyme assembly.

    PubMed Central

    Kolodziej, P A; Young, R A

    1991-01-01

    Mutations in the three largest subunits of yeast RNA polymerase II (RPB1, RPB2, and RPB3) were investigated for their effects on RNA polymerase II structure and assembly. Among 23 temperature-sensitive mutations, 6 mutations affected enzyme assembly, as assayed by immunoprecipitation of epitope-tagged subunits. In all six assembly mutants, RNA polymerase II subunits synthesized at the permissive temperature were incorporated into stably assembled, immunoprecipitable enzyme and remained stably associated when cells were shifted to the nonpermissive temperature, whereas subunits synthesized at the nonpermissive temperature were not incorporated into a completely assembled enzyme. The observation that subunit subcomplexes accumulated in assembly-mutant cells at the nonpermissive temperature led us to investigate whether these subcomplexes were assembly intermediates or merely byproducts of mutant enzyme instability. The time course of assembly of RPB1, RPB2, and RPB3 was investigated in wild-type cells and subsequently in mutant cells. Glycerol gradient fractionation of extracts of cells pulse-labeled for various times revealed that a subcomplex of RPB2 and RPB3 appears soon after subunit synthesis and can be chased into fully assembled enzyme. The RPB2-plus-RPB3 subcomplexes accumulated in all RPB1 assembly mutants at the nonpermissive temperature but not in an RPB2 or RPB3 assembly mutant. These data indicate that RPB2 and RPB3 form a complex that subsequently interacts with RPB1 during the assembly of RNA polymerase II. Images PMID:1715023

  16. Symbiosis in Paramecium Bursaria.

    PubMed

    Karakashian, M W

    1975-01-01

    Paramecium bursaria normally appears green dut to several hundred symbiotic Chlorella which are dispersed throughout its cytoplasm. The symbionts are situated within individual vacuoles and these alga-vacuole complexes grow and divide at a rate compatible with that of the paramecium. The symbiotic units also persist through conjugation and the subsequent reorganization of the host. Studies of the benefit of the symbiosis to the ciliate hosts have shown that they are able to grow and survive better than aposymbiotic animals in environments deficient in bacteria. The symbionts are also able to extract nourishment from the host when it is well fed and they are deprived of light. The biochemical nature of these exchanges has not been determined. Potential symbionts usually enter the host in food vacuoles. If they are ingested in sufficient numbers, they are able to interfere with the normal course of host digestion, perhaps by preventing the release of digestive enzymes into the food vacuole. All natural symbionts of P. bursaria appear able to reinfect aposymbiotic cells. Some freeliving strains of Chlorella and related algae are also infective, but these associations are relatively unstable and provide little evident benefit to the host. Host susceptibility to infection by certain strains of free-living algae is invariably lost with time. This loss is specific and often rapid, but it does not occur simultaneously in subcultures derived from the original susceptible culture. The basis for these susceptibility changes is still unknown, but they may be related to long-lasting effect of the previous symbionts on the digestive efficiency of the paramecium host. PMID:785659

  17. Mutations in the white gene of Drosophila melanogaster affecting ABC transporters that determine eye colouration.

    PubMed

    Mackenzie, S M; Brooker, M R; Gill, T R; Cox, G B; Howells, A J; Ewart, G D

    1999-07-15

    The white, brown and scarlet genes of Drosophila melanogaster encode proteins which transport guanine or tryptophan (precursors of the red and brown eye colour pigments) and belong to the ABC transporter superfamily. Current models envisage that the white and brown gene products interact to form a guanine specific transporter, while white and scarlet gene products interact to form a tryptophan transporter. In this study, we report the nucleotide sequence of the coding regions of five white alleles isolated from flies with partially pigmented eyes. In all cases, single amino acid changes were identified, highlighting residues with roles in structure and/or function of the transporters. Mutations in w(cf) (G589E) and w(sat) (F590G) occur at the extracellular end of predicted transmembrane helix 5 and correlate with a major decrease in red pigments in the eyes, while brown pigments are near wild-type levels. Therefore, those residues have a more significant role in the guanine transporter than the tryptophan transporter. Mutations identified in w(crr) (H298N) and w(101) (G243S) affect amino acids which are highly conserved among the ABC transporter superfamily within the nucleotide binding domain. Both cause substantial and similar decreases of red and brown pigments indicating that both tryptophan and guanine transport are impaired. The mutation identified in w(Et87) alters an amino acid within an intracellular loop between transmembrane helices 2 and 3 of the predicted structure. Red and brown pigments are reduced to very low levels by this mutation indicating this loop region is important for the function of both guanine and tryptophan transporters. PMID:10407069

  18. Mutations along the pituitary-gonadal axis affecting sexual maturation: novel information from transgenic and knockout mice.

    PubMed

    Huhtaniemi, Ilpo

    2006-07-25

    During the last 10 years, numerous activating and inactivating mutations have been detected in the genes encoding the two gonadotrophins, luteinising hormone (LH) and follicle-stimulating hormone (FSH), as well as their cognate receptors (R), LHR and FSHR. Because activation of the hypothalamic-pituitary-gonadal axis is a crucial event in the onset and progression of puberty, mutations affecting gonadotrophin action have major influence on this developmental process. Many of the phenotypic effects observed have been expected on the basis of the existing information about gonadotrophin action (e.g. delayed puberty), but also many unexpected findings have been made, including the lack of phenotype in women with activating LHR mutations, and the discrepancy in phenotypes of men with inactivating mutations of FSHbeta (azoospermia and infertility) and FSHR (oligozoospermia and subfertility). Some of the possible mutations, such as inactivating LHbeta and activating FSHR mutations in women, have not yet been detected. Genetically modified mice provide relevant phenocopies for the human mutations and serve as good models for studies on molecular pathogenesis of these conditions. They may also predict phenotypes of the mutations that have not yet been detected in humans. We review here briefly the effects of gonadotrophin subunit and receptor mutations on puberty in humans and contrast the information with findings on genetically modified mice with similar mutations.

  19. Both diet and gene mutation induced obesity affect oocyte quality in mice

    PubMed Central

    Hou, Yan-Jun; Zhu, Cheng-Cheng; Duan, Xing; Liu, Hong-Lin; Wang, Qiang; Sun, Shao-Chen

    2016-01-01

    Obesity was shown to cause reproductive dysfunctions such as reduced conception, infertility and early pregnancy loss. However, the possible effects of obesity on oocyte quality are still not fully understood. In this study we investigated the effects of both diet and gene mutation induced obesity on impairments in mouse oocyte polarization, oxidative stress, and epigenetic modifications. Our results showed that high-fat diet induced obesity (HFD) and gene mutation induced obesity (ob/ob) could both impair oocyte meiotic maturation, disrupt spindle morphology, and reduce oocyte polarity. Oocytes from obese mice underwent oxidative stress, as shown by high DHE and ROS levels. Abnormal mitochondrial distributions and structures were observed in oocytes from obese groups of mice and early apoptosis signals were detected, which suggesting that oxidative stress had impaired mitochondrial function and resulted in oocyte apoptosis. Our results also showed that 5 mC levels and H3K9 and H3K27 methylation levels were altered in oocytes from obese mice, which indicated that DNA methylation and histone methylation had been affected. Our results showed that both HFD and ob/ob induced obesity affected oocyte maturation and that oxidative stress-induced early apoptosis and altered epigenetic modifications may be the reasons for reduced oocyte quality in obese mice. PMID:26732298

  20. Mutations in SPT16/CDC68 suppress cis- and trans-acting mutations that affect promoter function in Saccharomyces cerevisiae.

    PubMed Central

    Malone, E A; Clark, C D; Chiang, A; Winston, F

    1991-01-01

    SPT16 was previously identified as a high-copy-number suppressor of delta insertion mutations in the 5' regions of the HIS4 and LYS2 genes of Saccharomyces cerevisiae. We have constructed null mutations in the SPT16 gene and have demonstrated that it is essential for growth. Temperature-sensitive-lethality spt16 alleles have been isolated and shown to be pleiotropic; at a temperature permissive for growth, spt16 mutations suppress delta insertion mutations, a deletion of the SUC2 upstream activating sequence, and mutations in trans-acting genes required for both SUC2 and Ty expression. In addition, SPT16 is identical to CDC68, a gene previously shown to be required for passage through the cell cycle control point START. However, at least some transcriptional effects caused by spt16 mutations are independent of arrest at START. These results and those in the accompanying paper (A. Rowley, R. A. Singer, and G. C. Johnston, Mol. Cell. Biol. 11:5718-5726, 1991) indicate that SPT16/CDC68 is required for normal transcription of many loci in S. cerevisiae. Images PMID:1922073

  1. A novel MIP gene mutation analysis in a Chinese family affected with congenital progressive punctate cataract.

    PubMed

    Ding, Xuchen; Zhou, Nan; Lin, Hui; Chen, Jianjun; Zhao, Chunyuan; Zhou, Guangkai; Hejtmancik, J Fielding; Qi, Yanhua

    2014-01-01

    Congenital cataracts are one of the leading causes of visual impairment and blindness in children, and genetic factors play an important role in their development. This study aimed to identify the genetic defects associated with autosomal dominant congenital progressive punctate cataracts in a Chinese family and to explore the potential pathogenesis. Detailed family history and clinical data were recorded, and all the family members' blood samples were collected for DNA extraction. Linkage analysis was performed by microsatellite markers that are associated with punctate cataracts, and logarithm (base 10) of odds (LOD) scores were calculated using the LINKAGE program. Positive two-point LOD scores were obtained at markers D12S1622 (Zmax = 2.71 at θ = 0.0), D12S1724 (Zmax = 2.71 at θ = 0.0), and D12S90 (Zmax = 2.71 at θ = 0.0), which flank the major intrinsic protein of lens fiber (MIP) gene on chromosomal region 12q13. Direct sequencing of the encoding region of the MIP gene revealed a novel mutation (G>D) in exon 4 at nucleotide 644, which caused a substitution of glycine to aspartic acid at codon 215 (p.G215D) for the MIP protein. The mutation cosegregated with all patients with congenital progressive punctate cataracts, but it was absent in the healthy members. Bioinformatics analysis predicted that the mutation affects the function of the MIP protein. The wild type (WT) and G215D mutant of MIP were transfected with green fluorescent protein (GFP) into Hela cells separately, and it was found that the G215D mutant was aberrantly located in the cytoplasm instead of in the plasma membrane. In summary, our study presented genetic and functional evidence linking the new MIP mutation of G215D to autosomal dominant congenital cataracts, which adds to the list of MIP mutations linked to congenital progressive punctate cataracts.

  2. Rare Mutations of CACNB2 Found in Autism Spectrum Disease-Affected Families Alter Calcium Channel Function

    PubMed Central

    Breitenkamp, Alexandra F. S.; Matthes, Jan; Nass, Robert Daniel; Sinzig, Judith; Lehmkuhl, Gerd; Nürnberg, Peter; Herzig, Stefan

    2014-01-01

    Autism Spectrum Disorders (ASD) are complex neurodevelopmental diseases clinically defined by dysfunction of social interaction. Dysregulation of cellular calcium homeostasis might be involved in ASD pathogenesis, and genes coding for the L-type calcium channel subunits CaV1.2 (CACNA1C) and CaVβ2 (CACNB2) were recently identified as risk loci for psychiatric diseases. Here, we present three rare missense mutations of CACNB2 (G167S, S197F, and F240L) found in ASD-affected families, two of them described here for the first time (G167S and F240L). All these mutations affect highly conserved regions while being absent in a sample of ethnically matched controls. We suggest the mutations to be of physiological relevance since they modulate whole-cell Ba2+ currents through calcium channels when expressed in a recombinant system (HEK-293 cells). Two mutations displayed significantly decelerated time-dependent inactivation as well as increased sensitivity of voltage-dependent inactivation. In contrast, the third mutation (F240L) showed significantly accelerated time-dependent inactivation. By altering the kinetic parameters, the mutations are reminiscent of the CACNA1C mutation causing Timothy Syndrome, a Mendelian disease presenting with ASD. In conclusion, the results of our first-time biophysical characterization of these three rare CACNB2 missense mutations identified in ASD patients support the hypothesis that calcium channel dysfunction may contribute to autism. PMID:24752249

  3. Clinical and structural impact of mutations affecting the residue Phe367 of FOXP3 in patients with IPEX syndrome.

    PubMed

    Colobran, Roger; Álvarez de la Campa, Elena; Soler-Palacín, Pere; Martín-Nalda, Andrea; Pujol-Borrell, Ricardo; de la Cruz, Xavier; Martínez-Gallo, Mónica

    2016-02-01

    Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic autoimmune disease characterized by early-onset life-threatening multisystemic autoimmunity. This rare hereditary disorder is caused by loss-of-function mutations in the gene encoding the forkhead box P3 (FOXP3) transcription factor, which plays a key role in the differentiation and function of CD4(+)CD25(+) natural regulatory T cells (Tregs), essential for the establishment and maintenance of natural tolerance. We identified a novel mutation in the FOXP3 gene affecting the Phe367 residue of the protein (F367V) in a family with three male siblings affected by IPEX. Two other mutations affecting the FOXP3 Phe367 residue (F367L and F367C) have been described previously. This unique situation of three mutations affecting the same residue in FOXP3 led us to study the molecular impact of these mutations on the structure of FOXP3 protein. Structure analysis showed that Phe367 is involved in a rich interaction network related to both monomer and dimer structure stabilization, and is crucial for FOXP3 regulatory activity. The relevance of this location is confirmed by the results of SIFT and PolyPhen-2 pathogenicity predictions for F367V mutation. In summary, as assessment of the pathogenicity of a novel mutation is crucial to achieve a proper molecular diagnosis, we analysed the impact of mutations affecting the Phe367 residue using a combined approach that provides a mechanistic view of their pathogenic effect. PMID:26748374

  4. P-element mutations affecting embryonic peripheral nervous system development in Drosophila melanogaster

    SciTech Connect

    Kania, A.; Salzberg, A.; Bhat, M.

    1995-04-01

    The Drosophila embryonic peripheral nervous system (PNS) is an excellent model system to study the molecular mechanisms governing neural development. To identify genes controlling PNS development, we screened 2000 lethal P-element insertion strains. The PNS of mutant embryos was examined using the neural specific marker MAb 22C10, and 92 mutant strains were retained for further analysis. Genetic and cytological analysis of these strains shows that 42 mutations affect previously isolated genes that are known to be required for PNS development: longitudinals lacking (19), mastermind (15), numb (4), big brain (2), and spitz (2). The remaining 50 mutations were classified into 29 complementation groups and the P-element insertions were cytologically mapped. The mutants were classified in five major classes on the basis of their phenotype: gain of neurons, loss of neurons, organizational defects, pathfinding defects and morphological defects. Herein we report the preliminary phenotypic characterization of each of these complementation groups as well as the embryonic lacZ expression pattern of each P-element strain. Our analysis indicates that in most of the P-element insertion strains, the lacZ reporter gene is not expressed in the developing PNS. 52 refs., 5 figs., 5 tabs.

  5. GENETIC LINKAGE OF MUTATIONAL SITES AFFECTING SIMILAR CHARACTERS IN PNEUMOCOCCUS AND STREPTOCOCCUS.

    PubMed

    RAVIN, A W; DESA, J H

    1964-01-01

    Ravin, Arnold W. (University of Rochester, Rochester, N.Y.), and Joscelyn D. H. De Sa. Genetic linkage of mutational sites affecting similar characters in pneumococcus and streptococcus. J. Bacteriol. 87:86-96. 1964.-By interspecific transformation, deoxyribonucleic acid (DNA) determinants conferring resistance to high levels of streptomycin in pneumococcus were found to be allelic with DNA determinants conferring low levels of streptomycin resistance in the Challis and NBSI strains of streptococcus. The reciprocal transformation (low resistance pneumococcus x high resistance streptococcus) led to the same conclusion. In addition, determinants controlling resistance to erythromycin in pneumococcus and the Challis strain of streptococcus were found to become closely linked after interspecific transformation. Modifier genes influencing the phenotype conferred by mutations at the streptomycin-resistance locus differentiate species to a certain extent. The results demonstrate that transformations between pneumococcus and streptococcus are not due to episomes, but involve recombinational events in which genetic material of the host species is replaced by homologous material that performed a similar function in the donor species.

  6. Mutations in cadherin 23 affect tip links in zebrafish sensory hair cells.

    PubMed

    Söllner, Christian; Rauch, Gerd-Jörg; Siemens, Jan; Geisler, Robert; Schuster, Stephan C; Müller, Ulrich; Nicolson, Teresa

    2004-04-29

    Hair cells have highly organized bundles of apical projections, or stereocilia, that are deflected by sound and movement. Displacement of stereocilia stretches linkages at the tips of stereocilia that are thought to gate mechanosensory channels. To identify the molecular machinery that mediates mechanotransduction in hair cells, zebrafish mutants were identified with defects in balance and hearing. In sputnik mutants, stereociliary bundles are splayed to various degrees, with individuals displaying reduced or absent mechanotransduction. Here we show that the defects in sputnik mutants are caused by mutations in cadherin 23 (cdh23). Mutations in Cdh23 also cause deafness and vestibular defects in mice and humans, and the protein is present in hair bundles. We show that zebrafish Cdh23 protein is concentrated near the tips of hair bundles, and that tip links are absent in homozygous sputnik(tc317e) larvae. Moreover, tip links are absent in larvae carrying weak alleles of cdh23 that affect mechanotransduction but not hair bundle integrity. We conclude that Cdh23 is an essential tip link component required for hair-cell mechanotransduction. PMID:15057246

  7. Mutation in fucose synthesis gene of Klebsiella pneumoniae affects capsule composition and virulence in mice.

    PubMed

    Pan, Po-Chang; Chen, Hui-Wen; Wu, Po-Kuan; Wu, Yu-Yang; Lin, Chun-Hung; Wu, June H

    2011-02-01

    The emerging pathogenicity of Klebsiella pneumoniae (KP) is evident by the increasing number of clinical cases of liver abscess (LA) due to KP infection. A unique property of KP is its thick mucoid capsule. The bacterial capsule has been found to contain fucose in KP strains causing LA but not in those causing urinary tract infections. The products of the gmd and wcaG genes are responsible for converting mannose to fucose in KP. A KP strain, KpL1, which is known to have a high death rate in infected mice, was mutated by inserting an apramycin-resistance gene into the gmd. The mutant expressed genes upstream and downstream of gmd, but not gmd itself, as determined by reverse transcriptase polymerase chain reaction. The DNA mapping confirmed the disruption of the gmd gene. This mutant decreased its ability to kill infected mice and showed decreased virulence in infected HepG2 cells. Compared with wild-type KpL1, the gmd mutant lost fucose in capsular polysaccharides, increased biofilm formation and interacted more readily with macrophages. The mutant displayed morphological changes with long filament forms and less uniform sizes. The mutation also converted the serotype from K1 of wild-type to K2 and weak K3. The results indicate that disruption of the fucose synthesis gene affected the pathophysiology of this bacterium and may be related to the virulence of this KpL1 strain.

  8. Glutamine synthetase-constitutive mutation affecting the glnALG upstream promoter of Escherichia coli.

    PubMed Central

    León, P; Romero, D; Garciarrubio, A; Bastarrachea, F; Covarrubias, A A

    1985-01-01

    The spontaneous gln-76 mutation of Escherichia coli (Osorio et al., Mol. Gen. Genet. 194:114-123, 1984) was previously shown to be responsible for the cis-dominant constitutive expression of the glnA gene in the absence of a glnG-glnF activator system. Nucleotide sequence analysis has now revealed that gln-76 is a single transversion T.A to A.T, an up-promoter mutation affecting the -10 region of glnAp1, the upstream promoter of the glnALG control region. Both, wild-type and gln-76 DNA control regions were cloned into the promoter-probe plasmid pKO1. Galactokinase activity determinations of cells carrying the fused plasmids showed 10-fold more effective expression mediated by gln-76 than by the glnA wild-type control region. Primer extension experiments with RNA from strains carrying the gln-76 control region indicated that the transcription initiation sites were the same in both the gln-76 mutant and the wild type. Images PMID:2866175

  9. A genetic screen for zygotic embryonic lethal mutations affecting cuticular morphology in the wasp Nasonia vitripennis.

    PubMed Central

    Pultz, M A; Zimmerman, K K; Alto, N M; Kaeberlein, M; Lange, S K; Pitt, J N; Reeves, N L; Zehrung, D L

    2000-01-01

    We have screened for zygotic embryonic lethal mutations affecting cuticular morphology in Nasonia vitripennis (Hymenoptera; Chalcidoidea). Our broad goal was to investigate the use of Nasonia for genetically surveying conservation and change in regulatory gene systems, as a means to understand the diversity of developmental strategies that have arisen during the course of evolution. Specifically, we aim to compare anteroposterior patterning gene functions in two long germ band insects, Nasonia and Drosophila. In Nasonia, unfertilized eggs develop as haploid males while fertilized eggs develop as diploid females, so the entire genome can be screened for recessive zygotic mutations by examining the progeny of F1 females. We describe 74 of >100 lines with embryonic cuticular mutant phenotypes, including representatives of coordinate, gap, pair-rule, segment polarity, homeotic, and Polycomb group functions, as well as mutants with novel phenotypes not directly comparable to those of known Drosophila genes. We conclude that Nasonia is a tractable experimental organism for comparative developmental genetic study. The mutants isolated here have begun to outline the extent of conservation and change in the genetic programs controlling embryonic patterning in Nasonia and Drosophila. PMID:10866651

  10. Four novel cystic fibrosis mutations in splice junction sequences affecting the CFTR nucleotide binding folds

    SciTech Connect

    Doerk, T.; Wulbrand, U.; Tuemmler, B. )

    1993-03-01

    Single cases of the four novel splice site mutations 1525[minus]1 G [r arrow] A (intron 9), 3601[minus]2 A [r arrow] G (intron 18), 3850[minus]3 T [r arrow] G (intron 19), and 4374+1 G [r arrow] T (intron 23) were detected in the CFTR gene of cystic fibrosis patients of Indo-Iranian, Turkish, Polish, and Germany descent. The nucleotide substitutions at the +1, [minus]1, and [minus]2 positions all destroy splice sites and lead to severe disease alleles associated with features typical of gastrointestinal and pulmonary cystic fibrosis disease. The 3850[minus]3 T-to-G change was discovered in a very mildly affected 33-year-old [Delta]F508 compound heterozygote, suggesting that the T-to-G transversion at the less conserved [minus]3 position of the acceptor splice site may retain some wildtype function. 13 refs., 1 fig., 2 tabs.

  11. A family with a dystrophin gene mutation specifically affecting dystrophin expression in the heart

    SciTech Connect

    Muntoni, F.; Davies, K.; Dubowitz, V.

    1994-09-01

    We recently described a family with X-linked dilated cardiomyopathy where a large deletion in the muscle promoter region of the dystrophin gene was associated with a severe dilated cardiomyopathy in absence of clinical skeletal muscle involvement. The deletion removed the entire muscle promoter region, the first muscle exon and part of intron 1. The brain and Purkinje cell promoters were not affected by the deletion. Despite the lack of both the muscle promoter and the first muscle exon, dystrophin was detected immunocytochemically in relative high levels in the skeletal muscle of the affected males. We have now found that both the brain and Purkinje cell promoters were transcribed at high levels in the skeletal muscle of these individuals. This phenomenon, that does not occur in normal skeletal muscle, indicates that these two isoforms, physiologically expressed mainly in the central nervous system, can be transcribed and be functionally active in skeletal muscle under specific circumstances. Contrary to what is observed in skeletal muscle, dystrophin was not detected in the heart of one affected male using immunocytochemistry and an entire panel of anti-dystrophin antibodies. This was most likely the cause for the pronounced cardiac fibrosis observed and eventually responsible for the severe cardiac involvement invariably seen in seven affected males. In conclusion, the mutation of the muscle promoter, first muscle exon and part of intron 1 specifically affected expression of dystrophin in the heart. We believe that this deletion removes sequences involved in regulation of dystrophin expression in the heart and are at the moment characterizing other families with X-linked cardiomyopathy secondary to a dystrophinopathy.

  12. The prevalence of BRCA1 mutations in Chinese patients with early onset breast cancer and affected relatives

    PubMed Central

    Sng, J-H; Chang, J; Feroze, F; Rahman, N; Tan, W; Lim, S; Lehnert, M; Pool, S van der; Wong, J

    2000-01-01

    The purpose of this study was to determine the prevalence of BRCA1 mutations in Chinese breast cancer patients in Singapore. BRCA1 analysis was conducted in consecutive patients with breast cancer before the age of 40 years (76 women), or whose relatives had breast or ovarian cancer (16 women). Ten patients had both early onset breast cancer and affected relatives. Genomic DNA from peripheral mononuclear blood cells was studied by using the protein transcription–translation assay (exon 11) and single-strand conformational polymorphism, with subsequent DNA sequencing. All six disease-causing mutations occurred in women under 40 years (8.6%) with three occurring in patients under 35 years (three out of 22 patients, 13.6%). Mis-sense mutations of unknown significance were found in three patients. Two of the ten women with affected relatives under 40 years had BRCA1 mutations. The prevalence of BRCA1 mutations in Chinese patients with early onset breast cancer is similar to that observed in Caucasian women. Most Chinese patients with affected relatives were not carriers of BRCA1 mutations. © 2000 Cancer Research Campaign PMID:10682662

  13. Balancing Protein Stability and Activity in Cancer: A New Approach for Identifying Driver Mutations Affecting CBL Ubiquitin Ligase Activation.

    PubMed

    Li, Minghui; Kales, Stephen C; Ma, Ke; Shoemaker, Benjamin A; Crespo-Barreto, Juan; Cangelosi, Andrew L; Lipkowitz, Stanley; Panchenko, Anna R

    2016-02-01

    Oncogenic mutations in the monomeric Casitas B-lineage lymphoma (Cbl) gene have been found in many tumors, but their significance remains largely unknown. Several human c-Cbl (CBL) structures have recently been solved, depicting the protein at different stages of its activation cycle and thus providing mechanistic insight underlying how stability-activity tradeoffs in cancer-related proteins-may influence disease onset and progression. In this study, we computationally modeled the effects of missense cancer mutations on structures representing four stages of the CBL activation cycle to identify driver mutations that affect CBL stability, binding, and activity. We found that recurrent, homozygous, and leukemia-specific mutations had greater destabilizing effects on CBL states than random noncancer mutations. We further tested the ability of these computational models, assessing the changes in CBL stability and its binding to ubiquitin-conjugating enzyme E2, by performing blind CBL-mediated EGFR ubiquitination assays in cells. Experimental CBL ubiquitin ligase activity was in agreement with the predicted changes in CBL stability and, to a lesser extent, with CBL-E2 binding affinity. Two thirds of all experimentally tested mutations affected the ubiquitin ligase activity by either destabilizing CBL or disrupting CBL-E2 binding, whereas about one-third of tested mutations were found to be neutral. Collectively, our findings demonstrate that computational methods incorporating multiple protein conformations and stability and binding affinity evaluations can successfully predict the functional consequences of cancer mutations on protein activity, and provide a proof of concept for mutations in CBL. PMID:26676746

  14. Lymphocyte telomere length is long in BRCA1 and BRCA2 mutation carriers regardless of cancer-affected status

    PubMed Central

    McGuffog, Lesley; Barrowdale, Daniel; Frost, Debra; Ellis, Steve D.; Platte, Radka; Fineberg, Elena; Izatt, Louise; Adlard, Julian; Bardwell, Julian; Brewer, Carole; Cole, Trevor; Cook, Jackie; Davidson, Rosemary; Donaldson, Alan; Dorkins, Huw; Douglas, Fiona; Eason, Jacqueline; Houghton, Catherine; Kennedy, M. John; McCann, Emma; Miedzybrobzka, Zosia; Murray, Alex; Porteous, Mary E.; Rogers, Mark T.; Side, Lucy E.; Tischkowitz, Marc; Walker, Lisa; Hodgson, Shirley; Eccles, Diana M.; Morrison, Patrick J.; Evans, D. Gareth; Eeles, Rosalind A.; Antoniou, Antonis C.; Easton, Douglas F.

    2014-01-01

    Background Telomere length has been linked to risk of common diseases, including cancer, and has previously been proposed as a biomarker for cancer risk. Germline BRCA1 and BRCA2 mutations predispose to breast, ovarian and other cancer types. Methods We investigated telomere length in BRCA mutation carriers and their non-carrier relatives and further examined whether telomere length is a modifier of cancer risk in mutation carriers. We measured mean telomere length in DNA extracted from whole blood using high-throughput Q-PCR. Participants were from the EMBRACE study in the UK and Eire (n=4,822) and comprised BRCA1 (n=1,628) and BRCA2 (n=1,506) mutation carriers and their non-carrier relatives (n=1,688). Results We find no significant evidence that mean telomere length is associated with breast or ovarian cancer risk in BRCA mutation carriers. However, we find mutation carriers to have longer mean telomere length than their non-carrier relatives (all carriers vs. non-carriers, P-trend=0.0018), particularly in families with BRCA2 mutations (BRCA2 mutation carriers vs. all non-carriers, P-trend=0.0016). Our findings lend little support to the hypothesis that short mean telomere length predisposes to cancer. Conversely, our main and unexpected finding is that BRCA mutation carriers (regardless of cancer status) have longer telomeres than their non-mutation carrier, non-cancer-affected relatives. The longer telomere length in BRCA2 mutation carriers is consistent with its role in DNA damage response. Conclusions Overall, it appears that increased telomere length may be a consequence of these mutations, but is not itself directly related to the increased cancer risk in carriers. Impact The finding that mutation carriers to have longer mean telomere lengths than their non-carrier relatives is unexpected but biologically plausible and could open up new lines of research into the functions of the BRCA proteins. To our knowledge, this is the largest study of telomere length

  15. Mutations Affecting the SAND Domain of DEAF1 Cause Intellectual Disability with Severe Speech Impairment and Behavioral Problems

    PubMed Central

    Vulto-van Silfhout, Anneke T.; Rajamanickam, Shivakumar; Jensik, Philip J.; Vergult, Sarah; de Rocker, Nina; Newhall, Kathryn J.; Raghavan, Ramya; Reardon, Sara N.; Jarrett, Kelsey; McIntyre, Tara; Bulinski, Joseph; Ownby, Stacy L.; Huggenvik, Jodi I.; McKnight, G. Stanley; Rose, Gregory M.; Cai, Xiang; Willaert, Andy; Zweier, Christiane; Endele, Sabine; de Ligt, Joep; van Bon, Bregje W.M.; Lugtenberg, Dorien; de Vries, Petra F.; Veltman, Joris A.; van Bokhoven, Hans; Brunner, Han G.; Rauch, Anita; de Brouwer, Arjan P.M.; Carvill, Gemma L.; Hoischen, Alexander; Mefford, Heather C.; Eichler, Evan E.; Vissers, Lisenka E.L.M.; Menten, Björn; Collard, Michael W.; de Vries, Bert B.A.

    2014-01-01

    Recently, we identified in two individuals with intellectual disability (ID) different de novo mutations in DEAF1, which encodes a transcription factor with an important role in embryonic development. To ascertain whether these mutations in DEAF1 are causative for the ID phenotype, we performed targeted resequencing of DEAF1 in an additional cohort of over 2,300 individuals with unexplained ID and identified two additional individuals with de novo mutations in this gene. All four individuals had severe ID with severely affected speech development, and three showed severe behavioral problems. DEAF1 is highly expressed in the CNS, especially during early embryonic development. All four mutations were missense mutations affecting the SAND domain of DEAF1. Altered DEAF1 harboring any of the four amino acid changes showed impaired transcriptional regulation of the DEAF1 promoter. Moreover, behavioral studies in mice with a conditional knockout of Deaf1 in the brain showed memory deficits and increased anxiety-like behavior. Our results demonstrate that mutations in DEAF1 cause ID and behavioral problems, most likely as a result of impaired transcriptional regulation by DEAF1. PMID:24726472

  16. Rare variants analysis of neurexin-1β in autism reveals a novel start codon mutation affecting protein levels at synapses.

    PubMed

    Camacho-Garcia, Rafael J; Hervás, Amaia; Toma, Claudio; Balmaña, Noemí; Cormand, Bru; Martinez-Mir, Amalia; Scholl, Francisco G

    2013-12-01

    Neurexins are synaptic plasma membrane proteins encoded by three genes (NRXN1, -2, -3) with alternative promoters. Mutations in neurexin genes have been identified in different neurodevelopmental disorders, including autism. Recently, two point mutations altering the translation initiation site of NRXN1β (c.-3G>T and c.3G>T) have been described in patients with autism and mental retardation. In this study, we analyzed the NRXN1β gene in a sample of 153 patients with autism. We report the identification of a novel mutation, c.3G>A (p.Met1), affecting the translation initiation site. Expression analysis showed that the c.3G>A mutation switches the translation start site of NRXN1β to an in-frame downstream methionine and decreases synaptic levels of the mutant protein in cultured neurons. These data reinforce a role for synaptic defects of NRXN1β in neurodevelopmental disorders.

  17. A mutation in the Xanthomonas oryzae pv. oryzae wxoD gene affects xanthan production and chemotaxis.

    PubMed

    Nam, Jae-Young; Kim, Hong-Il; Lee, Chang-Soo; Park, Young-Jin

    2013-11-01

    Xanthomonas oryzae pv. oryzae causes bacterial blight in rice (Oryza sativa L.). The effect of a mutation in the wxoD gene, that encodes a putative O-antigen acetylase, on xanthan production as well as bacterial chemotaxis was investigated. The mutation increased xanthan production by 52 %. The mutant strain was non-motile on semi-solid agar swarm plates. In addition, several genes involved in chemotaxis, including the cheW, cheV, cheR, and cheD genes, were down-regulated by a mutation in the wxoD gene. Thus, the mutation in the wxoD gene affects xanthan production as well as bacterial chemotaxis. However, the wxoD gene is not essential for the virulence of X. oryzae.

  18. Psychological Distress, Anxiety, and Depression of Cancer-Affected BRCA1/2 Mutation Carriers: a Systematic Review.

    PubMed

    Ringwald, Johanna; Wochnowski, Christina; Bosse, Kristin; Giel, Katrin Elisabeth; Schäffeler, Norbert; Zipfel, Stephan; Teufel, Martin

    2016-10-01

    Understanding the intermediate- and long-term psychological consequences of genetic testing for cancer patients has led to encouraging research, but a clear consensus of the psychosocial impact and clinical routine for cancer-affected BRCA1 and BRCA2 mutation carriers is still missing. We performed a systematic review of intermediate- and long-term studies investigating the psychological impact like psychological distress, anxiety, and depression in cancer-affected BRCA mutation carriers compared to unaffected mutation carriers. This review included the screening of 1243 studies. Eight intermediate- and long-term studies focusing on distress, anxiety, and depression symptoms among cancer-affected mutation carriers at least six months after the disclosure of genetic testing results were included. Studies reported a great variety of designs, methods, and patient outcomes. We found evidence indicating that cancer-affected mutation carriers experienced a negative effect in relation to psychological well-being in terms of an increase in symptoms of distress, anxiety, and depression in the first months after test disclosure. In the intermediate- and long-term, no significant clinical relevant symptoms occurred. However, none of the included studies used specific measurements, which can clearly identify psychological burdens of cancer-affected mutation carriers. We concluded that current well-implemented distress screening instruments are not sufficient for precisely identifying the psychological burden of genetic testing. Therefore, future studies should implement coping strategies, specific personality structures, the impact of genetic testing, supportive care needs and disease management behaviour to clearly screen for the possible intermediate- and long-term psychological impact of a positive test disclosure. PMID:27074860

  19. Psychological Distress, Anxiety, and Depression of Cancer-Affected BRCA1/2 Mutation Carriers: a Systematic Review.

    PubMed

    Ringwald, Johanna; Wochnowski, Christina; Bosse, Kristin; Giel, Katrin Elisabeth; Schäffeler, Norbert; Zipfel, Stephan; Teufel, Martin

    2016-10-01

    Understanding the intermediate- and long-term psychological consequences of genetic testing for cancer patients has led to encouraging research, but a clear consensus of the psychosocial impact and clinical routine for cancer-affected BRCA1 and BRCA2 mutation carriers is still missing. We performed a systematic review of intermediate- and long-term studies investigating the psychological impact like psychological distress, anxiety, and depression in cancer-affected BRCA mutation carriers compared to unaffected mutation carriers. This review included the screening of 1243 studies. Eight intermediate- and long-term studies focusing on distress, anxiety, and depression symptoms among cancer-affected mutation carriers at least six months after the disclosure of genetic testing results were included. Studies reported a great variety of designs, methods, and patient outcomes. We found evidence indicating that cancer-affected mutation carriers experienced a negative effect in relation to psychological well-being in terms of an increase in symptoms of distress, anxiety, and depression in the first months after test disclosure. In the intermediate- and long-term, no significant clinical relevant symptoms occurred. However, none of the included studies used specific measurements, which can clearly identify psychological burdens of cancer-affected mutation carriers. We concluded that current well-implemented distress screening instruments are not sufficient for precisely identifying the psychological burden of genetic testing. Therefore, future studies should implement coping strategies, specific personality structures, the impact of genetic testing, supportive care needs and disease management behaviour to clearly screen for the possible intermediate- and long-term psychological impact of a positive test disclosure.

  20. TERT promoter mutations in bladder cancer affect patient survival and disease recurrence through modification by a common polymorphism

    PubMed Central

    Rachakonda, P. Sivaramakrishna; Hosen, Ismail; de Verdier, Petra J.; Fallah, Mahdi; Heidenreich, Barbara; Ryk, Charlotta; Wiklund, N. Peter; Steineck, Gunnar; Schadendorf, Dirk; Hemminki, Kari; Kumar, Rajiv

    2013-01-01

    The telomerase reverse transcriptase (TERT) promoter, an important element of telomerase expression, has emerged as a target of cancer-specific mutations. Originally described in melanoma, the mutations in TERT promoter have been shown to be common in certain other tumor types that include glioblastoma, hepatocellular carcinoma, and bladder cancer. To fully define the occurrence and effect of the TERT promoter mutations, we investigated tumors from a well-characterized series of 327 patients with urothelial cell carcinoma of bladder. The somatic mutations, mainly at positions −124 and −146 bp from ATG start site that create binding motifs for E-twenty six/ternary complex factors (Ets/TCF), affected 65.4% of the tumors, with even distribution across different stages and grades. Our data showed that a common polymorphism rs2853669, within a preexisting Ets2 binding site in the TERT promoter, acts as a modifier of the effect of the mutations on survival and tumor recurrence. The patients with the mutations showed poor survival in the absence [hazard ratio (HR) 2.19, 95% confidence interval (CI) 1.02–4.70] but not in the presence (HR 0.42, 95% CI 0.18–1.01) of the variant allele of the polymorphism. The mutations in the absence of the variant allele were highly associated with the disease recurrence in patients with Tis, Ta, and T1 tumors (HR 1.85, 95% CI 1.11–3.08). The TERT promoter mutations are the most common somatic lesions in bladder cancer with clinical implications. The association of the mutations with patient survival and disease recurrence, subject to modification by a common polymorphism, can be a unique putative marker with individualized prognostic potential. PMID:24101484

  1. Detection of three nonsense mutations and one missense mutation in the interleukin-2 receptor [gamma] chain gene in SCIDX1 that differently affect the mRNA processing

    SciTech Connect

    Markiewicz, S.; Fischer, A.; Saint Basile, G. de ); Subtil, A.; Dautry-Varsat, A. )

    1994-05-01

    The interleukin-2 receptor [gamma] (IL-2R[gamma]) chain gene encodes a 64-kDa protein that not only composes the high-affinity form of the IL-2 binding receptor in association with the 2R [alpha] and [beta] chains, but also participates in at least the IL-4 and IL-7 receptor complexes. Mutations in this gene have recently been shown to cause X-linked severe combined immunodeficiency (SCIDX1). This disease of the immune system results from an early block of T lymphocyte and natural killer (NK) cell differentiation, which leads to a severe cellular and humoral immune defect that is lethal unless treated by bone marrow transplantation. Analysis of the IL-2R[gamma] gene in SCIDX1 patients has revealed the presence of heterogeneous mutations principally located in the extracellular domain of the molecule. We report here three intraexonic mutations and one deletion in the IL-2R[gamma] gene in four SCIDX1 patients. These mutations appear to differentially affect RNA processing, either by decreasing IL-2R[gamma] mRNA level or by the skipping of a constitutive exon. 16 refs., 1 fig.

  2. Mutation-induced protein interaction kinetics changes affect apoptotic network dynamic properties and facilitate oncogenesis

    PubMed Central

    Zhao, Linjie; Sun, Tanlin; Pei, Jianfeng; Ouyang, Qi

    2015-01-01

    It has been a consensus in cancer research that cancer is a disease caused primarily by genomic alterations, especially somatic mutations. However, the mechanism of mutation-induced oncogenesis is not fully understood. Here, we used the mitochondrial apoptotic pathway as a case study and performed a systematic analysis of integrating pathway dynamics with protein interaction kinetics to quantitatively investigate the causal molecular mechanism of mutation-induced oncogenesis. A mathematical model of the regulatory network was constructed to establish the functional role of dynamic bifurcation in the apoptotic process. The oncogenic mutation enrichment of each of the protein functional domains involved was found strongly correlated with the parameter sensitivity of the bifurcation point. We further dissected the causal mechanism underlying this correlation by evaluating the mutational influence on protein interaction kinetics using molecular dynamics simulation. We analyzed 29 matched mutant–wild-type and 16 matched SNP—wild-type protein systems. We found that the binding kinetics changes reflected by the changes of free energy changes induced by protein interaction mutations, which induce variations in the sensitive parameters of the bifurcation point, were a major cause of apoptosis pathway dysfunction, and mutations involved in sensitive interaction domains show high oncogenic potential. Our analysis provided a molecular basis for connecting protein mutations, protein interaction kinetics, network dynamics properties, and physiological function of a regulatory network. These insights provide a framework for coupling mutation genotype to tumorigenesis phenotype and help elucidate the logic of cancer initiation. PMID:26170328

  3. Mutation-induced protein interaction kinetics changes affect apoptotic network dynamic properties and facilitate oncogenesis.

    PubMed

    Zhao, Linjie; Sun, Tanlin; Pei, Jianfeng; Ouyang, Qi

    2015-07-28

    It has been a consensus in cancer research that cancer is a disease caused primarily by genomic alterations, especially somatic mutations. However, the mechanism of mutation-induced oncogenesis is not fully understood. Here, we used the mitochondrial apoptotic pathway as a case study and performed a systematic analysis of integrating pathway dynamics with protein interaction kinetics to quantitatively investigate the causal molecular mechanism of mutation-induced oncogenesis. A mathematical model of the regulatory network was constructed to establish the functional role of dynamic bifurcation in the apoptotic process. The oncogenic mutation enrichment of each of the protein functional domains involved was found strongly correlated with the parameter sensitivity of the bifurcation point. We further dissected the causal mechanism underlying this correlation by evaluating the mutational influence on protein interaction kinetics using molecular dynamics simulation. We analyzed 29 matched mutant-wild-type and 16 matched SNP--wild-type protein systems. We found that the binding kinetics changes reflected by the changes of free energy changes induced by protein interaction mutations, which induce variations in the sensitive parameters of the bifurcation point, were a major cause of apoptosis pathway dysfunction, and mutations involved in sensitive interaction domains show high oncogenic potential. Our analysis provided a molecular basis for connecting protein mutations, protein interaction kinetics, network dynamics properties, and physiological function of a regulatory network. These insights provide a framework for coupling mutation genotype to tumorigenesis phenotype and help elucidate the logic of cancer initiation.

  4. Oakleaf: an S locus-linked mutation of Primula vulgaris that affects leaf and flower development.

    PubMed

    Cocker, Jonathan M; Webster, Margaret A; Li, Jinhong; Wright, Jonathan; Kaithakottil, Gemy; Swarbreck, David; Gilmartin, Philip M

    2015-10-01

    In Primula vulgaris outcrossing is promoted through reciprocal herkogamy with insect-mediated cross-pollination between pin and thrum form flowers. Development of heteromorphic flowers is coordinated by genes at the S locus. To underpin construction of a genetic map facilitating isolation of these S locus genes, we have characterised Oakleaf, a novel S locus-linked mutant phenotype. We combine phenotypic observation of flower and leaf development, with classical genetic analysis and next-generation sequencing to address the molecular basis of Oakleaf. Oakleaf is a dominant mutation that affects both leaf and flower development; plants produce distinctive lobed leaves, with occasional ectopic meristems on the veins. This phenotype is reminiscent of overexpression of Class I KNOX-homeodomain transcription factors. We describe the structure and expression of all eight P. vulgaris PvKNOX genes in both wild-type and Oakleaf plants, and present comparative transcriptome analysis of leaves and flowers from Oakleaf and wild-type plants. Oakleaf provides a new phenotypic marker for genetic analysis of the Primula S locus. We show that none of the Class I PvKNOX genes are strongly upregulated in Oakleaf leaves and flowers, and identify cohorts of 507 upregulated and 314 downregulated genes in the Oakleaf mutant.

  5. Mutations in TSPEAR, Encoding a Regulator of Notch Signaling, Affect Tooth and Hair Follicle Morphogenesis

    PubMed Central

    Samuelov, Liat; Bertolini, Marta; Weissglas-Volkov, Daphna; Eskin-Schwartz, Marina; Malchin, Natalia; Bochner, Ron; Fainberg, Gilad; Goldberg, Ilan; Sugawara, Koji; Tsuruta, Daisuke; Morasso, Maria; Shalev, Stavit; Gallo, Richard L.; Shomron, Noam; Paus, Ralf; Sprecher, Eli

    2016-01-01

    Despite recent advances in our understanding of the pathogenesis of ectodermal dysplasias (EDs), the molecular basis of many of these disorders remains unknown. In the present study, we aimed at elucidating the genetic basis of a new form of ED featuring facial dysmorphism, scalp hypotrichosis and hypodontia. Using whole exome sequencing, we identified 2 frameshift and 2 missense mutations in TSPEAR segregating with the disease phenotype in 3 families. TSPEAR encodes the thrombospondin-type laminin G domain and EAR repeats (TSPEAR) protein, whose function is poorly understood. TSPEAR knock-down resulted in altered expression of genes known to be regulated by NOTCH and to be involved in murine hair and tooth development. Pathway analysis confirmed that down-regulation of TSPEAR in keratinocytes is likely to affect Notch signaling. Accordingly, using a luciferase-based reporter assay, we showed that TSPEAR knock-down is associated with decreased Notch signaling. In addition, NOTCH1 protein expression was reduced in patient scalp skin. Moreover, TSPEAR silencing in mouse hair follicle organ cultures was found to induce apoptosis in follicular epithelial cells, resulting in decreased hair bulb diameter. Collectively, these observations indicate that TSPEAR plays a critical, previously unrecognized role in human tooth and hair follicle morphogenesis through regulation of the Notch signaling pathway. PMID:27736875

  6. Mutations in the CRE pocket of bacterial RNA polymerase affect multiple steps of transcription.

    PubMed

    Petushkov, Ivan; Pupov, Danil; Bass, Irina; Kulbachinskiy, Andrey

    2015-07-13

    During transcription, the catalytic core of RNA polymerase (RNAP) must interact with the DNA template with low-sequence specificity to ensure efficient enzyme translocation and RNA extension. Unexpectedly, recent structural studies of bacterial promoter complexes revealed specific interactions between the nontemplate DNA strand at the downstream edge of the transcription bubble (CRE, core recognition element) and a protein pocket formed by core RNAP (CRE pocket). We investigated the roles of these interactions in transcription by analyzing point amino acid substitutions and deletions in Escherichia coli RNAP. The mutations affected multiple steps of transcription, including promoter recognition, RNA elongation and termination. In particular, we showed that interactions of the CRE pocket with a nontemplate guanine immediately downstream of the active center stimulate RNA-hairpin-dependent transcription pausing but not other types of pausing. Thus, conformational changes of the elongation complex induced by nascent RNA can modulate CRE effects on transcription. The results highlight the roles of specific core RNAP-DNA interactions at different steps of RNA synthesis and suggest their importance for transcription regulation in various organisms.

  7. Mutations in the CRE pocket of bacterial RNA polymerase affect multiple steps of transcription

    PubMed Central

    Petushkov, Ivan; Pupov, Danil; Bass, Irina; Kulbachinskiy, Andrey

    2015-01-01

    During transcription, the catalytic core of RNA polymerase (RNAP) must interact with the DNA template with low-sequence specificity to ensure efficient enzyme translocation and RNA extension. Unexpectedly, recent structural studies of bacterial promoter complexes revealed specific interactions between the nontemplate DNA strand at the downstream edge of the transcription bubble (CRE, core recognition element) and a protein pocket formed by core RNAP (CRE pocket). We investigated the roles of these interactions in transcription by analyzing point amino acid substitutions and deletions in Escherichia coli RNAP. The mutations affected multiple steps of transcription, including promoter recognition, RNA elongation and termination. In particular, we showed that interactions of the CRE pocket with a nontemplate guanine immediately downstream of the active center stimulate RNA-hairpin-dependent transcription pausing but not other types of pausing. Thus, conformational changes of the elongation complex induced by nascent RNA can modulate CRE effects on transcription. The results highlight the roles of specific core RNAP–DNA interactions at different steps of RNA synthesis and suggest their importance for transcription regulation in various organisms. PMID:25990734

  8. Beta Thalassemia: mutations which affect processing of the beta-Globin mRNA precursor.

    PubMed

    Kantor, J A; Turner, P H; Nienhuis, A W

    1980-08-01

    To define the molecular lesion which causes decreased beta-globin synthesis in beta+ thalessemia, four patients of diverse ethnic origin were studied. Each had a 2--3 fold higher concentration of beta-globin mRNA precursor than that found in control bone marrow cells from patients with sickle cell anemia. Globin RNA metabolism was analyzed in two of these patients. Transcription of the beta-globin gene appeared to be normal, since analysis of nuclear RNA indicated that beta-globin mRNA synthesis exceeded that of alpha in a 2 hr pulse but the cytoplasm contained a relative deficiency of labeled beta-globin mRNA. An abnormal RNA species approximately 650 nucleotides in length, which contained sequences transcribed from both the large intron and coding portions of the beta-globin gene, was found in one patient's bone marrow cells. The second patient's cells contained a significant amount of a 1320 nucleotide RNA species, not initially evident in normal cells, from which part but not all of the large intervening sequence had been removed. Our data thus indicate that mutations which affect RNA processing cause beta thalessemia.

  9. Genetics of mutations affecting the development of a barley floral bract.

    PubMed Central

    Pozzi, C; Faccioli, P; Terzi, V; Stanca, A M; Cerioli, S; Castiglioni, P; Fink, R; Capone, R; Müller, K J; Bossinger, G; Rohde, W; Salamini, F

    2000-01-01

    Two groups of mutants that affect the morphology of the lemma, a floral bract of barley, are described. The first comprises phenotypes associated with mutant alleles of calcaroides loci. On the lemma of these mutants, a well-organized neomorphic structure is formed, termed the sac. We provide a morphological description of wild-type (WT) and mutant lemmas, based on scanning electron microscopy (SEM), showing that both consist of similar tissues, but that the mutant is characterized by reversed growth polarity. The sac is a unique structure among grasses, and it is remarkable that recessive mutations at five different genetic loci lead to the same organ. The second group of mutants carry recessive alleles of two leafy lemma genes, both of which are necessary to cause the transformation of the lemma into a structure having all characteristics of a vegetative leaf, as shown by SEM analysis. The presence of sheath, blade, and ligule in the mutant lemma suggests that wild-type lemma development is interrupted at a leaf-like stage. The genes cal a, b, C, d, 23, lel1, and lel2 have now been mapped at precise positions on linkage groups 2, 7, 7, 3, 7, 5, and 7, respectively. The mutants considered in this article are unaffected in other floral organs. A model for lemma development is suggested. PMID:10757774

  10. Effector diversification within compartments of the Leptosphaeria maculans genome affected by Repeat-Induced Point mutations

    PubMed Central

    Rouxel, Thierry; Grandaubert, Jonathan; Hane, James K.; Hoede, Claire; van de Wouw, Angela P.; Couloux, Arnaud; Dominguez, Victoria; Anthouard, Véronique; Bally, Pascal; Bourras, Salim; Cozijnsen, Anton J.; Ciuffetti, Lynda M.; Degrave, Alexandre; Dilmaghani, Azita; Duret, Laurent; Fudal, Isabelle; Goodwin, Stephen B.; Gout, Lilian; Glaser, Nicolas; Linglin, Juliette; Kema, Gert H. J.; Lapalu, Nicolas; Lawrence, Christopher B.; May, Kim; Meyer, Michel; Ollivier, Bénédicte; Poulain, Julie; Schoch, Conrad L.; Simon, Adeline; Spatafora, Joseph W.; Stachowiak, Anna; Turgeon, B. Gillian; Tyler, Brett M.; Vincent, Delphine; Weissenbach, Jean; Amselem, Joëlle; Quesneville, Hadi; Oliver, Richard P.; Wincker, Patrick; Balesdent, Marie-Hélène; Howlett, Barbara J.

    2011-01-01

    Fungi are of primary ecological, biotechnological and economic importance. Many fundamental biological processes that are shared by animals and fungi are studied in fungi due to their experimental tractability. Many fungi are pathogens or mutualists and are model systems to analyse effector genes and their mechanisms of diversification. In this study, we report the genome sequence of the phytopathogenic ascomycete Leptosphaeria maculans and characterize its repertoire of protein effectors. The L. maculans genome has an unusual bipartite structure with alternating distinct guanine and cytosine-equilibrated and adenine and thymine (AT)-rich blocks of homogenous nucleotide composition. The AT-rich blocks comprise one-third of the genome and contain effector genes and families of transposable elements, both of which are affected by repeat-induced point mutation, a fungal-specific genome defence mechanism. This genomic environment for effectors promotes rapid sequence diversification and underpins the evolutionary potential of the fungus to adapt rapidly to novel host-derived constraints. PMID:21326234

  11. Arbuscular mycorrhizal symbiosis-mediated tomato tolerance to drought.

    PubMed

    Chitarra, Walter; Maserti, Biancaelena; Gambino, Giorgio; Guerrieri, Emilio; Balestrini, Raffaella

    2016-07-01

    A multidisciplinary approach, involving eco-physiological, morphometric, biochemical and molecular analyses, has been used to study the impact of two different AM fungi, i.e. Funneliformis mosseae and Rhizophagus intraradices, on tomato response to water stress. Overall, results show that AM symbiosis positively affects the tolerance to drought in tomato with a different plant response depending on the involved AM fungal species. PMID:27359066

  12. P-Element Insertion Alleles of Essential Genes on the Third Chromosome of Drosophila Melanogaster: Mutations Affecting Embryonic Pns Development

    PubMed Central

    Salzberg, A.; Prokopenko, S. N.; He, Y.; Tsai, P.; Pal, M.; Maroy, P.; Glover, D. M.; Deak, P.; Bellen, H. J.

    1997-01-01

    To identify novel genes and to isolate tagged mutations in known genes that are required for the development of the peripheral nervous system (PNS), we have screened a novel collection of 2460 strains carrying lethal or semilethal P-element insertions on the third chromosome. Monoclonal antibody 22C10 was used as a marker to visualize the embryonic PNS. We identified 109 mutant strains that exhibited reproducible phenotypes in the PNS. Cytological and genetic analyses of these strains indicated that 87 mutations affect previously identified genes: tramtrack (n = 18 alleles), string (n = 15), cyclin A (n = 13), single-minded (n = 13), Delta (n = 9), neuralized (n = 4), pointed (n = 4), extra macrochaetae (n = 4), prospero (n = 3), tartan (n = 2), and pebble (n = 2). In addition, 13 mutations affect genes that we identified recently in a chemical mutagenesis screen designed to isolate similar mutants: hearty (n = 3), dorsotonals (n = 2), pavarotti (n = 2), sanpodo (n = 2), dalmatian (n = 1), missensed (n = 1), senseless (n = 1), and sticky ch1 (n = 1). The remaining nine mutations define seven novel complementation groups. The data presented here demonstrate that this collection of P elements will be useful for the identification and cloning of novel genes on the third chromosome, since >70% of mutations identified in the screen are caused by the insertion of a P element. A comparison between this screen and a chemical mutagenesis screen undertaken earlier highlights the complementarity of the two types of genetic screens. PMID:9409832

  13. Genetic and biochemical characterization of mutations affecting the ability of the yeast Pachysolen tannophilus to metabolize D-xylose

    SciTech Connect

    James, A.P.; Zahab, D.M.; Mahmourides, G.; Maleszka, R.; Schneider, H. )

    1989-11-01

    Induced mutants, selected for their defective growth on D-xylose while retaining the ability to grow normally on D-glucose, were studied in Pachysolen tannophilus, a yeast capable of converting D-xylose to ethanol. Fourteen of the mutations were found to occur at nine distinct loci, and data indicated that many more loci remain to be detected. Most of the mutations were pleiotropic in character, and the expression of some of them was much affected by nutritional conditions and by genetic background. Mutations at several loci resulted in poor growth on at least one compound that was either an intermediate of the tricarboxylic acid cycle, succinate or {alpha}-ketoglutarate, or on compounds metabolizable via this cycle, ethanol or glycerol. An initial biochemical characterization of the mutants was undertaken. Analysis for xylose reductase, xylitol dehydrogenase, and xylulose kinase activity showed that one or more of these activities was affected in 12 of 13 mutants. However, drastic reduction in activity of a single enzyme was confined to that of xylitol dehydrogenase by mutations at three different loci and to that of D-xylose reductase by mutation at another locus. Growth of these latter four mutants was normal on all carbon sources tested that were not five-carbon sugars.

  14. Biallelic mutations in huntington disease: A new case with just one affected parent, review of the literature and terminology.

    PubMed

    Uhlmann, Wendy R; Peñaherrera, Maria S; Robinson, Wendy P; Milunsky, Jeff M; Nicholson, Jane M; Albin, Roger L

    2015-05-01

    Patients with biallelic mutations for Huntington disease (HD) are rare. We present a 46-year-old female with two expanded Huntingtin (HTT) alleles with just one known affected parent. This is the first reported patient with molecular studies performed to exclude HTT uniparental disomy (UPD). The proband had biparental inheritance of HTT alleles (42/44 CAG repeats). Given the negative UPD results, the proband's unaffected mother either had a reduced penetrance allele that expanded into the full mutation range during transmission to our patient or an unknown full HTT mutation and died before symptom onset, unlikely given no family history of HD and asymptomatic at age 59. We made the novel observation in our literature review that most patients with biallelic HD did not have two full HTT mutations. Most had one HTT allele that was in the intermediate or reduced penetrance ranges or 40 CAG repeats, the lowest limit of the full mutation range. Although the number of patients is small, when an allele in these size ranges was present, generally the age of HD onset was in the 50s. If the second HTT allele had >45 repeats, then onset was typically 20s-30s. While similar ages of onset have been reported for patients with one or two HTT mutations, patients with biallelic mutations may have later onset if an expanded HTT allele has ≤40 CAG repeats. Finally, we propose that "biallelic mutations" or "compound heterozygosity" are more accurate descriptive terms than "homozygosity" when there are two non-identical expanded HTT alleles.

  15. Biallelic mutations in huntington disease: A new case with just one affected parent, review of the literature and terminology.

    PubMed

    Uhlmann, Wendy R; Peñaherrera, Maria S; Robinson, Wendy P; Milunsky, Jeff M; Nicholson, Jane M; Albin, Roger L

    2015-05-01

    Patients with biallelic mutations for Huntington disease (HD) are rare. We present a 46-year-old female with two expanded Huntingtin (HTT) alleles with just one known affected parent. This is the first reported patient with molecular studies performed to exclude HTT uniparental disomy (UPD). The proband had biparental inheritance of HTT alleles (42/44 CAG repeats). Given the negative UPD results, the proband's unaffected mother either had a reduced penetrance allele that expanded into the full mutation range during transmission to our patient or an unknown full HTT mutation and died before symptom onset, unlikely given no family history of HD and asymptomatic at age 59. We made the novel observation in our literature review that most patients with biallelic HD did not have two full HTT mutations. Most had one HTT allele that was in the intermediate or reduced penetrance ranges or 40 CAG repeats, the lowest limit of the full mutation range. Although the number of patients is small, when an allele in these size ranges was present, generally the age of HD onset was in the 50s. If the second HTT allele had >45 repeats, then onset was typically 20s-30s. While similar ages of onset have been reported for patients with one or two HTT mutations, patients with biallelic mutations may have later onset if an expanded HTT allele has ≤40 CAG repeats. Finally, we propose that "biallelic mutations" or "compound heterozygosity" are more accurate descriptive terms than "homozygosity" when there are two non-identical expanded HTT alleles. PMID:25736541

  16. A deleterious RNF43 germline mutation in a severely affected serrated polyposis kindred.

    PubMed

    Taupin, Douglas; Lam, Wesley; Rangiah, David; McCallum, Larissa; Whittle, Belinda; Zhang, Yafei; Andrews, Daniel; Field, Matthew; Goodnow, Christopher C; Cook, Matthew C

    2015-01-01

    We report a germline nonsense mutation within the extracellular domain of the RING finger ubiquitin ligase RNF43, segregating with a severe form of serrated polyposis within a kindred. The finding provides evidence that inherited RNF43 mutations define a familial cancer syndrome.

  17. Isolation of Mutations Affecting Neural Circuitry Required for Grooming Behavior in Drosophila Melanogaster

    PubMed Central

    Phillis, R. W.; Bramlage, A. T.; Wotus, C.; Whittaker, A.; Gramates, L. S.; Seppala, D.; Farahanchi, F.; Caruccio, P.; Murphey, R. K.

    1993-01-01

    We have developed a screen for the isolation of mutations that produce neural defects in adult Drosophila melanogaster. In this screen, we identify mutants as flies unable to remove a light coating of applied dust in a 2-hr period. We have recovered and characterized six mutations and have found that they produce coordination defects and some have reduced levels of reflex responsiveness to the stimulation of single tactile sensory bristles. The grooming defects produced by all six of the mutations are recessive, and each of the mutations has been genetically mapped. We have also used our assay to test the grooming ability of stocks containing mutations that produce known neural defects. PMID:8454205

  18. Cell Biology of Cnidarian-Dinoflagellate Symbiosis

    PubMed Central

    Allemand, Denis; Weis, Virginia M.

    2012-01-01

    Summary: The symbiosis between cnidarians (e.g., corals or sea anemones) and intracellular dinoflagellate algae of the genus Symbiodinium is of immense ecological importance. In particular, this symbiosis promotes the growth and survival of reef corals in nutrient-poor tropical waters; indeed, coral reefs could not exist without this symbiosis. However, our fundamental understanding of the cnidarian-dinoflagellate symbiosis and of its links to coral calcification remains poor. Here we review what we currently know about the cell biology of cnidarian-dinoflagellate symbiosis. In doing so, we aim to refocus attention on fundamental cellular aspects that have been somewhat neglected since the early to mid-1980s, when a more ecological approach began to dominate. We review the four major processes that we believe underlie the various phases of establishment and persistence in the cnidarian/coral-dinoflagellate symbiosis: (i) recognition and phagocytosis, (ii) regulation of host-symbiont biomass, (iii) metabolic exchange and nutrient trafficking, and (iv) calcification. Where appropriate, we draw upon examples from a range of cnidarian-alga symbioses, including the symbiosis between green Hydra and its intracellular chlorophyte symbiont, which has considerable potential to inform our understanding of the cnidarian-dinoflagellate symbiosis. Ultimately, we provide a comprehensive overview of the history of the field, its current status, and where it should be going in the future. PMID:22688813

  19. Identification of a novel mutation in the PAX9 gene in a family affected by oligodontia and other dental anomalies.

    PubMed

    Tallón-Walton, Victòria; Manzanares-Céspedes, Maria Cristina; Arte, Sirpa; Carvalho-Lobato, Patricia; Valdivia-Gandur, Ivan; Garcia-Susperregui, Antonio; Ventura, Francesc; Nieminen, Pekka

    2007-12-01

    The objective of the present work was to study the phenotype and the genotype of three generations of a family affected by oligodontia and other dental anomalies. These family members also presented systemic conditions such as hypercholesterolemia, hypothyroidism, diabetes mellitus, scoliosis, and congenital cardiovascular anomalies. Clinical evaluation, panoramic radiographs, and anamnestic data were used for dental analysis. DNA extraction was carried out from gum samples or buccal swabs. A mutation was identified in six subjects across three generations affected by oligodontia, as well as different phenotypical manifestations, both systemic and oral. The previously undescribed PAX9 mutation was observed in the paired box (exon 2); this was a heterozygote transition of C175 to T, implying the change of arginine 59 for a termination codon. These results strongly suggested that the identified mutation was the etiological cause of the oligodontia. However, in two family members affected by both hypodontia and peg-shaped upper lateral incisors, no mutations in the PAX9 and MSX1 genes were identified. This fact underscores the importance that other presently unknown genes and developmental factors have in tooth development and in the etiology of dental anomalies. PMID:18028048

  20. Identification of a novel mutation in the PAX9 gene in a family affected by oligodontia and other dental anomalies.

    PubMed

    Tallón-Walton, Victòria; Manzanares-Céspedes, Maria Cristina; Arte, Sirpa; Carvalho-Lobato, Patricia; Valdivia-Gandur, Ivan; Garcia-Susperregui, Antonio; Ventura, Francesc; Nieminen, Pekka

    2007-12-01

    The objective of the present work was to study the phenotype and the genotype of three generations of a family affected by oligodontia and other dental anomalies. These family members also presented systemic conditions such as hypercholesterolemia, hypothyroidism, diabetes mellitus, scoliosis, and congenital cardiovascular anomalies. Clinical evaluation, panoramic radiographs, and anamnestic data were used for dental analysis. DNA extraction was carried out from gum samples or buccal swabs. A mutation was identified in six subjects across three generations affected by oligodontia, as well as different phenotypical manifestations, both systemic and oral. The previously undescribed PAX9 mutation was observed in the paired box (exon 2); this was a heterozygote transition of C175 to T, implying the change of arginine 59 for a termination codon. These results strongly suggested that the identified mutation was the etiological cause of the oligodontia. However, in two family members affected by both hypodontia and peg-shaped upper lateral incisors, no mutations in the PAX9 and MSX1 genes were identified. This fact underscores the importance that other presently unknown genes and developmental factors have in tooth development and in the etiology of dental anomalies.

  1. A novel reef coral symbiosis

    NASA Astrophysics Data System (ADS)

    Pantos, O.; Bythell, J. C.

    2010-09-01

    Reef building corals form close associations with unicellular microalgae, fungi, bacteria and archaea, some of which are symbiotic and which together form the coral holobiont. Associations with multicellular eukaryotes such as polychaete worms, bivalves and sponges are not generally considered to be symbiotic as the host responds to their presence by forming physical barriers with an active growth edge in the exoskeleton isolating the invader and, at a subcellular level, activating innate immune responses such as melanin deposition. This study describes a novel symbiosis between a newly described hydrozoan ( Zanclea margaritae sp. nov.) and the reef building coral Acropora muricata (= A. formosa), with the hydrozoan hydrorhiza ramifying throughout the coral tissues with no evidence of isolation or activation of the immune systems of the host. The hydrorhiza lacks a perisarc, which is typical of symbiotic species of this and related genera, including species that associate with other cnidarians such as octocorals. The symbiosis was observed at all sites investigated from two distant locations on the Great Barrier Reef, Australia, and appears to be host species specific, being found only in A. muricata and in none of 30 other species investigated at these sites. Not all colonies of A. muricata host the hydrozoans and both the prevalence within the coral population (mean = 66%) and density of emergent hydrozoan hydranths on the surface of the coral (mean = 4.3 cm-2, but up to 52 cm-2) vary between sites. The form of the symbiosis in terms of the mutualism-parasitism continuum is not known, although the hydrozoan possesses large stenotele nematocysts, which may be important for defence from predators and protozoan pathogens. This finding expands the known A. muricata holobiont and the association must be taken into account in future when determining the corals’ abilities to defend against predators and withstand stress.

  2. Identification of novel mutations in HEXA gene in children affected with Tay Sachs disease from India.

    PubMed

    Mistri, Mehul; Tamhankar, Parag M; Sheth, Frenny; Sanghavi, Daksha; Kondurkar, Pratima; Patil, Swapnil; Idicula-Thomas, Susan; Gupta, Sarita; Sheth, Jayesh

    2012-01-01

    Tay Sachs disease (TSD) is a neurodegenerative disorder due to β-hexosaminidase A deficiency caused by mutations in the HEXA gene. The mutations leading to Tay Sachs disease in India are yet unknown. We aimed to determine mutations leading to TSD in India by complete sequencing of the HEXA gene. The clinical inclusion criteria included neuroregression, seizures, exaggerated startle reflex, macrocephaly, cherry red spot on fundus examination and spasticity. Neuroimaging criteria included thalamic hyperdensities on CT scan/T1W images of MRI of the brain. Biochemical criteria included deficiency of hexosaminidase A (less than 2% of total hexosaminidase activity for infantile patients). Total leukocyte hexosaminidase activity was assayed by 4-methylumbelliferyl-N-acetyl-β-D-glucosamine lysis and hexosaminidase A activity was assayed by heat inactivation method and 4-methylumbelliferyl-N-acetyl-β-D-glucosamine-6-sulphate lysis method. The exons and exon-intron boundaries of the HEXA gene were bidirectionally sequenced using an automated sequencer. Mutations were confirmed in parents and looked up in public databases. In silico analysis for mutations was carried out using SIFT, Polyphen2, MutationT@ster and Accelrys Discovery Studio softwares. Fifteen families were included in the study. We identified six novel missense mutations, c.340 G>A (p.E114K), c.964 G>A (p.D322N), c.964 G>T (p.D322Y), c.1178C>G (p.R393P) and c.1385A>T (p.E462V), c.1432 G>A (p.G478R) and two previously reported mutations. c.1277_1278insTATC and c.508C>T (p.R170W). The mutation p.E462V was found in six unrelated families from Gujarat indicating a founder effect. A previously known splice site mutation c.805+1 G>C and another intronic mutation c.672+30 T>G of unknown significance were also identified. Mutations could not be identified in one family. We conclude that TSD patients from Gujarat should be screened for the common mutation p.E462V.

  3. Identification of novel mutations in HEXA gene in children affected with Tay Sachs disease from India.

    PubMed

    Mistri, Mehul; Tamhankar, Parag M; Sheth, Frenny; Sanghavi, Daksha; Kondurkar, Pratima; Patil, Swapnil; Idicula-Thomas, Susan; Gupta, Sarita; Sheth, Jayesh

    2012-01-01

    Tay Sachs disease (TSD) is a neurodegenerative disorder due to β-hexosaminidase A deficiency caused by mutations in the HEXA gene. The mutations leading to Tay Sachs disease in India are yet unknown. We aimed to determine mutations leading to TSD in India by complete sequencing of the HEXA gene. The clinical inclusion criteria included neuroregression, seizures, exaggerated startle reflex, macrocephaly, cherry red spot on fundus examination and spasticity. Neuroimaging criteria included thalamic hyperdensities on CT scan/T1W images of MRI of the brain. Biochemical criteria included deficiency of hexosaminidase A (less than 2% of total hexosaminidase activity for infantile patients). Total leukocyte hexosaminidase activity was assayed by 4-methylumbelliferyl-N-acetyl-β-D-glucosamine lysis and hexosaminidase A activity was assayed by heat inactivation method and 4-methylumbelliferyl-N-acetyl-β-D-glucosamine-6-sulphate lysis method. The exons and exon-intron boundaries of the HEXA gene were bidirectionally sequenced using an automated sequencer. Mutations were confirmed in parents and looked up in public databases. In silico analysis for mutations was carried out using SIFT, Polyphen2, MutationT@ster and Accelrys Discovery Studio softwares. Fifteen families were included in the study. We identified six novel missense mutations, c.340 G>A (p.E114K), c.964 G>A (p.D322N), c.964 G>T (p.D322Y), c.1178C>G (p.R393P) and c.1385A>T (p.E462V), c.1432 G>A (p.G478R) and two previously reported mutations. c.1277_1278insTATC and c.508C>T (p.R170W). The mutation p.E462V was found in six unrelated families from Gujarat indicating a founder effect. A previously known splice site mutation c.805+1 G>C and another intronic mutation c.672+30 T>G of unknown significance were also identified. Mutations could not be identified in one family. We conclude that TSD patients from Gujarat should be screened for the common mutation p.E462V. PMID:22723944

  4. A secondary symbiosis in progress?

    PubMed

    Okamoto, Noriko; Inouye, Isao

    2005-10-14

    Algae have acquired plastids by developing an endosymbiotic relationship with either a cyanobacterium (primary endosymbiosis) or other eukaryotic algae (secondary endosymbiosis). We report a protist, which we tentatively refer to as Hatena, that hosts an endosymbiotic green algal partner but inherits it unevenly. The endosymbiosis causes drastic morphological changes to both the symbiont and the host cell architecture. This type of life cycle, in which endosymbiont integration has only partially converted the host from predator to autotroph, may represent an early stage of plastid acquisition through secondary symbiosis. PMID:16224014

  5. Mutations altering the gammaretrovirus endoproteolytic motif affect glycosylation of the envelope glycoprotein and early events of the virus life cycle.

    PubMed

    Argaw, Takele; Wilson, Carolyn A

    2015-01-15

    Previously, we found that mutation of glutamine to proline in the endoproteolytic cleavage signal of the PERV-C envelope (RQKK to RPKK) resulted in non-infectious vectors. Here, we show that RPKK results in a non-infectious vector when placed in not only a PERV envelope, but also the envelope of a related gammaretrovirus, FeLV-B. The amino acid substitutions do not prevent envelope precursor cleavage, viral core and genome assembly, or receptor binding. Rather, the mutations result in the formation of hyperglycosylated glycoprotein and a reduction in the reverse transcribed minus strand synthesis and undetectable 2-LTR circular DNA in cells exposed to vectors with these mutated envelopes. Our findings suggest novel functions associated with the cleavage signal sequence that may affect trafficking through the glycosylation machinery of the cell. Further, the glycosylation status of the envelope appears to impact post-binding events of the viral life cycle, either membrane fusion, internalization, or reverse transcription.

  6. Sporadic infantile epileptic encephalopathy caused by mutations in PCDH19 resembles Dravet syndrome but mainly affects females.

    PubMed

    Depienne, Christel; Bouteiller, Delphine; Keren, Boris; Cheuret, Emmanuel; Poirier, Karine; Trouillard, Oriane; Benyahia, Baya; Quelin, Chloé; Carpentier, Wassila; Julia, Sophie; Afenjar, Alexandra; Gautier, Agnès; Rivier, François; Meyer, Sophie; Berquin, Patrick; Hélias, Marie; Py, Isabelle; Rivera, Serge; Bahi-Buisson, Nadia; Gourfinkel-An, Isabelle; Cazeneuve, Cécile; Ruberg, Merle; Brice, Alexis; Nabbout, Rima; Leguern, Eric

    2009-02-01

    Dravet syndrome (DS) is a genetically determined epileptic encephalopathy mainly caused by de novo mutations in the SCN1A gene. Since 2003, we have performed molecular analyses in a large series of patients with DS, 27% of whom were negative for mutations or rearrangements in SCN1A. In order to identify new genes responsible for the disorder in the SCN1A-negative patients, 41 probands were screened for micro-rearrangements with Illumina high-density SNP microarrays. A hemizygous deletion on chromosome Xq22.1, encompassing the PCDH19 gene, was found in one male patient. To confirm that PCDH19 is responsible for a Dravet-like syndrome, we sequenced its coding region in 73 additional SCN1A-negative patients. Nine different point mutations (four missense and five truncating mutations) were identified in 11 unrelated female patients. In addition, we demonstrated that the fibroblasts of our male patient were mosaic for the PCDH19 deletion. Patients with PCDH19 and SCN1A mutations had very similar clinical features including the association of early febrile and afebrile seizures, seizures occurring in clusters, developmental and language delays, behavioural disturbances, and cognitive regression. There were, however, slight but constant differences in the evolution of the patients, including fewer polymorphic seizures (in particular rare myoclonic jerks and atypical absences) in those with PCDH19 mutations. These results suggest that PCDH19 plays a major role in epileptic encephalopathies, with a clinical spectrum overlapping that of DS. This disorder mainly affects females. The identification of an affected mosaic male strongly supports the hypothesis that cellular interference is the pathogenic mechanism.

  7. The evolution of specificity in the legume-rhizobium symbiosis.

    PubMed

    Young, J P; Johnston, A W

    1989-11-01

    We know more about the partnership between legumes and their root-nodule bacteria than about any other symbiosis or any other plant-microbe interaction. In the light of recent research we are beginning to see details of an elaborate tapestry. The rhizobia are not a self-contained branch on the bacterial tree; their ancestry is intertwined with that of photosynthetic and pathogenic bacteria. Their host ranges, which vary enormously in breadth, overlap to form a tangled web of interconnections between plants and bacteria, and mechanisms of infection and nodule development are more diverse than we once thought. From genetic analysis of the bacteria we learn that specificity is not the province of special 'host-range determinants', but is affected by a wide range of genes with diverse modes of action. The symbiosis is a rich resource for evolutionary fact and speculation, but its complexity and diversity should warn us not to expect easy answers.

  8. Molecular modeling studies demonstrate key mutations that could affect the ligand recognition by influenza AH1N1 neuraminidase.

    PubMed

    Ramírez-Salinas, Gema L; García-Machorro, J; Quiliano, Miguel; Zimic, Mirko; Briz, Verónica; Rojas-Hernández, Saul; Correa-Basurto, J

    2015-11-01

    The goal of this study was to identify neuraminidase (NA) residue mutants from human influenza AH1N1 using sequences from 1918 to 2012. Multiple alignment studies of complete NA sequences (5732) were performed. Subsequently, the crystallographic structure of the 1918 influenza (PDB ID: 3BEQ-A) was used as a wild-type structure and three-dimensional (3-D) template for homology modeling of the mutated selected NA sequences. The 3-D mutated NAs were refined using molecular dynamics (MD) simulations (50 ns). The refined 3-D models were used to perform docking studies using oseltamivir. Multiple sequence alignment studies showed seven representative mutations (A232V, K262R, V263I, T264V, S367L, S369N, and S369K). MD simulations applied to 3-D NAs showed that each NA had different active-site shapes according to structural surface visualization and docking results. Moreover, Cartesian principal component analyses (cPCA) show structural differences among these NA structures caused by mutations. These theoretical results suggest that the selected mutations that are located outside of the active site of NA could affect oseltamivir recognition and could be associated with resistance to oseltamivir.

  9. Molecular modeling studies demonstrate key mutations that could affect the ligand recognition by influenza AH1N1 neuraminidase.

    PubMed

    Ramírez-Salinas, Gema L; García-Machorro, J; Quiliano, Miguel; Zimic, Mirko; Briz, Verónica; Rojas-Hernández, Saul; Correa-Basurto, J

    2015-11-01

    The goal of this study was to identify neuraminidase (NA) residue mutants from human influenza AH1N1 using sequences from 1918 to 2012. Multiple alignment studies of complete NA sequences (5732) were performed. Subsequently, the crystallographic structure of the 1918 influenza (PDB ID: 3BEQ-A) was used as a wild-type structure and three-dimensional (3-D) template for homology modeling of the mutated selected NA sequences. The 3-D mutated NAs were refined using molecular dynamics (MD) simulations (50 ns). The refined 3-D models were used to perform docking studies using oseltamivir. Multiple sequence alignment studies showed seven representative mutations (A232V, K262R, V263I, T264V, S367L, S369N, and S369K). MD simulations applied to 3-D NAs showed that each NA had different active-site shapes according to structural surface visualization and docking results. Moreover, Cartesian principal component analyses (cPCA) show structural differences among these NA structures caused by mutations. These theoretical results suggest that the selected mutations that are located outside of the active site of NA could affect oseltamivir recognition and could be associated with resistance to oseltamivir. PMID:26499499

  10. A critical functional missense mutation (H173R) in the bovine PROP1 gene significantly affects growth traits in cattle.

    PubMed

    Pan, Chuanying; Wu, Chongyang; Jia, Wenchao; Xu, Yao; Lei, Chuzhao; Hu, Shenrong; Lan, Xianyong; Chen, Hong

    2013-12-01

    The PROP1 protein, encoded by the prophet of Pit-1 (PROP1) gene, exhibits both DNA-binding and transcriptional activation abilities. Its expression leads to the ontogenesis of growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), and pituitary hormone. The missense mutation H173R in PROP1 may result in deficiencies of GH, PRL, TSH, and Pit-1, thereby affecting growth traits. The objective of this study was to characterize the H173R mutation within the PROP1 gene and examine its associations with growth traits in cattle. Accordingly, the H173R mutation was genotyped in 1207 cows belonging to five Chinese native breeds. Three genotypes were identified among the specimens, with genotype AA being the major one. Consequently, the "G" allele was the minor allele. Association testing revealed that the H173R mutation was significantly associated with body weight, average daily weight gain and physical parameters in the analyzed breeds. Interestingly, the cows with genotype AG and/or AA had superior growth traits compared with those expressing the GG genotype, in all tested breeds. These findings revealed that the "A" allele had positive effects on growth traits, which was consistent with the increasing binding ability and enhanced activation capacity associated with the bovine isoform PROP1-173H, representing the "A" allele. Therefore, the H173R mutation can be considered as a DNA marker for selecting individuals with superior growth traits, thereby contributing to research on breeding and genetics in the beef industry.

  11. Mutations in MCT8 in patients with Allan-Herndon-Dudley-syndrome affecting its cellular distribution.

    PubMed

    Kersseboom, Simone; Kremers, Gert-Jan; Friesema, Edith C H; Visser, W Edward; Klootwijk, Wim; Peeters, Robin P; Visser, Theo J

    2013-05-01

    Monocarboxylate transporter 8 (MCT8) is a thyroid hormone (TH)-specific transporter. Mutations in the MCT8 gene are associated with Allan-Herndon-Dudley Syndrome (AHDS), consisting of severe psychomotor retardation and disturbed TH parameters. To study the functional consequences of different MCT8 mutations in detail, we combined functional analysis in different cell types with live-cell imaging of the cellular distribution of seven mutations that we identified in patients with AHDS. We used two cell models to study the mutations in vitro: 1) transiently transfected COS1 and JEG3 cells, and 2) stably transfected Flp-in 293 cells expressing a MCT8-cyan fluorescent protein construct. All seven mutants were expressed at the protein level and showed a defect in T3 and T4 transport in uptake and metabolism studies. Three mutants (G282C, P537L, and G558D) had residual uptake activity in Flp-in 293 and COS1 cells, but not in JEG3 cells. Four mutants (G221R, P321L, D453V, P537L) were expressed at the plasma membrane. The mobility in the plasma membrane of P537L was similar to WT, but the mobility of P321L was altered. The other mutants studied (insV236, G282C, G558D) were predominantly localized in the endoplasmic reticulum. In essence, loss of function by MCT8 mutations can be divided in two groups: mutations that result in partial or complete loss of transport activity (G221R, P321L, D453V, P537L) and mutations that mainly disturb protein expression and trafficking (insV236, G282C, G558D). The cell type-dependent results suggest that MCT8 mutations in AHDS patients may have tissue-specific effects on TH transport probably caused by tissue-specific expression of yet unknown MCT8-interacting proteins. PMID:23550058

  12. Heavy metal stress in alders: Tolerance and vulnerability of the actinorhizal symbiosis.

    PubMed

    Bélanger, Pier-Anne; Bellenger, Jean-Philippe; Roy, Sébastien

    2015-11-01

    Alders have already demonstrated their potential for the revegetation of both mining and industrial sites. These actinorhizal trees and shrubs and the actinobacteria Frankia associate in a nitrogen-fixing symbiosis which could however be negatively affected by the presence of heavy metals, and accumulate them. In our hydroponic assay with black alders, quantification of the roots and shoots metal concentrations showed that, in the absence of stress, symbiosis increases Mo and Ni root content and simultaneously decreases Mo shoot content. Interestingly, the Mo shoot content also decreases in the presence of Ni, Cu, Pb, Zn and Cd for symbiotic alders. In symbiotic alders, Pb shoot translocation was promoted in presence of Pb. On the other hand, Cd exclusion in symbiotic root tissues was observed with Pb and Cd. In the presence of symbiosis, only Cd and Pb showed translocation into aerial tissues when present in the nutrient solution. Moreover, the translocation of Ni to shoot was prevented by symbiosis in the presence of Cd, Ni and Pb. The hydroponic experiment demonstrated that alders benefit from the symbiosis, producing more biomass (total, root and shoot) than non nodulated alders in control condition, and in the presence of metals (Cu, Ni, Zn, Pb and Cd). Heavy metals did not reduce the nodule numbers (SNN), but the presence of Zn or Cd did reduce nodule allocation. Our study suggests that the Frankia-alder symbiosis is a promising (and a compatible) plant-microorganism association for the revegetation of contaminated sites, with minimal risk of metal dispersion.

  13. Novel missense mutation in the GALNS gene in an affected patient with severe form of mucopolysaccharidosis type IVA.

    PubMed

    Seyedhassani, Seyed Mohammad; Hashemi-Gorji, Feyzollah; Yavari, Mahdieh; Mirfakhraie, Reza

    2015-10-23

    Mucopolysaccharidosis type IVA (MPS IVA), also known as Morquio A, is an autosomal recessive disorder characterized by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which causes major skeletal and connective tissue abnormalities and affects multiple organ systems. In this study, one MPS IVA patient with a severe form from consanguine large Iranian family has been investigated. To find a mutation, all of the 14 exons and intron-exon junctions of GALNS gene were sequenced. Sequencing results were analyzed using bioinformatic analysis in order to predict probable pathogenic effect of the variant. One novel homozygous missense mutation in exon 5, c.542A>G (p.Y181C), was found in the proband. That was predicted as being probably pathogenic by bioinformatics analysis. Segregation and familial study confirmed this pathogenic mutation. In conclusion, we have identified the novel mutation responsible for MPS IVA in an Iranian patient to assist in the diagnosis, genetic counseling and prenatal diagnosis of the affected families.

  14. HERC 1 Ubiquitin Ligase Mutation Affects Neocortical, CA3 Hippocampal and Spinal Cord Projection Neurons: An Ultrastructural Study

    PubMed Central

    Ruiz, Rocío; Pérez-Villegas, Eva María; Bachiller, Sara; Rosa, José Luis; Armengol, José Angel

    2016-01-01

    The spontaneous mutation tambaleante is caused by the Gly483Glu substitution in the highly conserved N terminal RCC1-like domain of the HERC1 protein, which leads to the increase of mutated protein levels responsible for cerebellar Purkinje cell death by autophagy. Until now, Purkinje cells have been the only central nervous neurons reported as being targeted by the mutation, and their degeneration elicits an ataxic syndrome in adult mutant mice. However, the ultrastructural analysis performed here demonstrates that signs of autophagy, such as autophagosomes, lysosomes, and altered mitochondria, are present in neocortical pyramidal, CA3 hippocampal pyramidal, and spinal cord motor neurons. The main difference is that the reduction in the number of neurons affected in the tambaleante mutation in the neocortex, the hippocampus, and the spinal cord is not so evident as the dramatic loss of cerebellar Purkinje cells. Interestingly, signs of autophagy are absent in both interneurons and neuroglia cells. Affected neurons have in common that they are projection neurons which receive strong and varied synaptic inputs, and possess the highest degree of neuronal activity. Therefore, because the integrity of the ubiquitin-proteasome system is essential for protein degradation and hence, for normal protein turnover, it could be hypothesized that the deleterious effects of the misrouting of these pathways would depend directly on the neuronal activity. PMID:27147983

  15. HERC 1 Ubiquitin Ligase Mutation Affects Neocortical, CA3 Hippocampal and Spinal Cord Projection Neurons: An Ultrastructural Study.

    PubMed

    Ruiz, Rocío; Pérez-Villegas, Eva María; Bachiller, Sara; Rosa, José Luis; Armengol, José Angel

    2016-01-01

    The spontaneous mutation tambaleante is caused by the Gly483Glu substitution in the highly conserved N terminal RCC1-like domain of the HERC1 protein, which leads to the increase of mutated protein levels responsible for cerebellar Purkinje cell death by autophagy. Until now, Purkinje cells have been the only central nervous neurons reported as being targeted by the mutation, and their degeneration elicits an ataxic syndrome in adult mutant mice. However, the ultrastructural analysis performed here demonstrates that signs of autophagy, such as autophagosomes, lysosomes, and altered mitochondria, are present in neocortical pyramidal, CA3 hippocampal pyramidal, and spinal cord motor neurons. The main difference is that the reduction in the number of neurons affected in the tambaleante mutation in the neocortex, the hippocampus, and the spinal cord is not so evident as the dramatic loss of cerebellar Purkinje cells. Interestingly, signs of autophagy are absent in both interneurons and neuroglia cells. Affected neurons have in common that they are projection neurons which receive strong and varied synaptic inputs, and possess the highest degree of neuronal activity. Therefore, because the integrity of the ubiquitin-proteasome system is essential for protein degradation and hence, for normal protein turnover, it could be hypothesized that the deleterious effects of the misrouting of these pathways would depend directly on the neuronal activity. PMID:27147983

  16. A Single Mutation in Chikungunya Virus Affects Vector Specificity and Epidemic Potential

    PubMed Central

    Tsetsarkin, Konstantin A; Vanlandingham, Dana L; McGee, Charles E; Higgs, Stephen

    2007-01-01

    Chikungunya virus (CHIKV) is an emerging arbovirus associated with several recent large-scale epidemics. The 2005–2006 epidemic on Reunion island that resulted in approximately 266,000 human cases was associated with a strain of CHIKV with a mutation in the envelope protein gene (E1-A226V). To test the hypothesis that this mutation in the epidemic CHIKV (strain LR2006 OPY1) might influence fitness for different vector species, viral infectivity, dissemination, and transmission of CHIKV were compared in Aedes albopictus, the species implicated in the epidemic, and the recognized vector Ae. aegypti. Using viral infectious clones of the Reunion strain and a West African strain of CHIKV, into which either the E1–226 A or V mutation was engineered, we demonstrated that the E1-A226V mutation was directly responsible for a significant increase in CHIKV infectivity for Ae. albopictus, and led to more efficient viral dissemination into mosquito secondary organs and transmission to suckling mice. This mutation caused a marginal decrease in CHIKV Ae. aegypti midgut infectivity, had no effect on viral dissemination, and was associated with a slight increase in transmission by Ae. aegypti to suckling mice in competition experiments. The effect of the E1-A226V mutation on cholesterol dependence of CHIKV was also analyzed, revealing an association between cholesterol dependence and increased fitness of CHIKV in Ae. albopictus. Our observation that a single amino acid substitution can influence vector specificity provides a plausible explanation of how this mutant virus caused an epidemic in a region lacking the typical vector. This has important implications with respect to how viruses may establish a transmission cycle when introduced into a new area. Due to the widespread distribution of Ae. albopictus, this mutation increases the potential for CHIKV to permanently extend its range into Europe and the Americas. PMID:18069894

  17. The ts111 Mutation of Paramecium tetraurelia Affects a Member of the Protein Palmitoylation Family.

    PubMed

    Prajer, Małgorzata; Tarcz, Sebastian

    2015-01-01

    The thermosensitive ts111 mutant of Parameciun tetraurelia carries a recessive mutation which causes cell death after 2-8 divisions at the restrictive temperature of 35 degrees C. Expression at 35 degrees C induces disassembly of the infraciliary lattice (ICL). In this study, we found that the ts111 mutation also results in significant abnormalities in the number and structure of contractile vacuole complexes (CVCs) and in their functioning at the restrictive temperature. In order to characterize the ts111 gene, the complementation cloning was performed by microinjection into the macronucleus of an indexed genomic DNA library. The mutation was complemented by a sequence of 852 bp, which differed from the mutant sequence by a single nucleotide substitution. The deduced protein sequence is 284 amino acids long. It contains a domain referred to as the DHHC domain, associated with 2 trans-membrane helices. The DHHC proteins belong to the Palmitoyl-Acyl Transferases (PATs) protein family, which is implicated in the protein palmitoylation process playing the role in protein addressing. The ts111 mutation induces the amino acid change, localized before the first membrane helix. Transformation of ts111 mutant cells with the TS111-GFP gene fusion showed the expected reparation restoring thermoresistance and also demonstrated a localization of the protein in contractile vacuoles, but not in the ICL. The entire gene silencing in wild type cells at restrictive temperature caused the same effect as the expression of a point mutation in ts111 mutant. The authors propose the following hypotheses: (i) function of CVCs at the restrictive temperature depends in Paramecium on the TS111 protein--a member of the PAT family, and the primary effect of the termosensitive ts111 mutation are morphological abnormalities and dysfunction of CVCs, (ii) disassembly of the ICL is a secondary effect of the ts111 mutation, which results from disturbed regulation of the intracellular concentration

  18. C-Nap1 mutation affects centriole cohesion and is associated with a Seckel-like syndrome in cattle.

    PubMed

    Floriot, Sandrine; Vesque, Christine; Rodriguez, Sabrina; Bourgain-Guglielmetti, Florence; Karaiskou, Anthi; Gautier, Mathieu; Duchesne, Amandine; Barbey, Sarah; Fritz, Sébastien; Vasilescu, Alexandre; Bertaud, Maud; Moudjou, Mohammed; Halliez, Sophie; Cormier-Daire, Valérie; Hokayem, Joyce E L; Nigg, Erich A; Manciaux, Luc; Guatteo, Raphaël; Cesbron, Nora; Toutirais, Geraldine; Eggen, André; Schneider-Maunoury, Sylvie; Boichard, Didier; Sobczak-Thépot, Joelle; Schibler, Laurent

    2015-01-01

    Caprine-like Generalized Hypoplasia Syndrome (SHGC) is an autosomal-recessive disorder in Montbéliarde cattle. Affected animals present a wide range of clinical features that include the following: delayed development with low birth weight, hind limb muscular hypoplasia, caprine-like thin head and partial coat depigmentation. Here we show that SHGC is caused by a truncating mutation in the CEP250 gene that encodes the centrosomal protein C-Nap1. This mutation results in centrosome splitting, which neither affects centriole ultrastructure and duplication in dividing cells nor centriole function in cilium assembly and mitotic spindle organization. Loss of C-Nap1-mediated centriole cohesion leads to an altered cell migration phenotype. This discovery extends the range of loci that constitute the spectrum of autosomal primary recessive microcephaly (MCPH) and Seckel-like syndromes. PMID:25902731

  19. C-Nap1 mutation affects centriole cohesion and is associated with a Seckel-like syndrome in cattle.

    PubMed

    Floriot, Sandrine; Vesque, Christine; Rodriguez, Sabrina; Bourgain-Guglielmetti, Florence; Karaiskou, Anthi; Gautier, Mathieu; Duchesne, Amandine; Barbey, Sarah; Fritz, Sébastien; Vasilescu, Alexandre; Bertaud, Maud; Moudjou, Mohammed; Halliez, Sophie; Cormier-Daire, Valérie; Hokayem, Joyce E L; Nigg, Erich A; Manciaux, Luc; Guatteo, Raphaël; Cesbron, Nora; Toutirais, Geraldine; Eggen, André; Schneider-Maunoury, Sylvie; Boichard, Didier; Sobczak-Thépot, Joelle; Schibler, Laurent

    2015-04-23

    Caprine-like Generalized Hypoplasia Syndrome (SHGC) is an autosomal-recessive disorder in Montbéliarde cattle. Affected animals present a wide range of clinical features that include the following: delayed development with low birth weight, hind limb muscular hypoplasia, caprine-like thin head and partial coat depigmentation. Here we show that SHGC is caused by a truncating mutation in the CEP250 gene that encodes the centrosomal protein C-Nap1. This mutation results in centrosome splitting, which neither affects centriole ultrastructure and duplication in dividing cells nor centriole function in cilium assembly and mitotic spindle organization. Loss of C-Nap1-mediated centriole cohesion leads to an altered cell migration phenotype. This discovery extends the range of loci that constitute the spectrum of autosomal primary recessive microcephaly (MCPH) and Seckel-like syndromes.

  20. The role of mutations affecting gonadotrophin secretion and action in disorders of pubertal development.

    PubMed

    Huhtaniemi, Ilpo T

    2002-03-01

    A number of mutations that disturb the development and function of the hypothalamic-pituitary-gonadal (HPG) axis and cause disturbances in pubertal development are known today. These mutations have effects at all levels of the HPG axis, from the migration of gonadotrophin releasing hormone (GnRH) neurones from the nasal cavity to the hypothalamus, GnRH secretion, GnRH action, pituitary gonadotroph differentiation, gonadotrophin synthesis and secretion, right through to gonadotrophin action. Most of the mutations are inactivating, thus causing hypogonadism and arrest or delay of pubertal development. One exception is the activating mutations of the LH receptor, which causes the male-limited gonadotrophin-independent precocious puberty. The human mutations and animal models with disrupted function of orthologous genes have clarified the molecular pathogenesis of hypogonadism and disturbances of pubertal development. The correct diagnosis of these disorders using molecular biological techniques is now possible. This allows the selection of specific treatments and correct counselling of the patients and their families.

  1. The shiverer mutation affects the persistence of Theiler's virus in the central nervous system.

    PubMed Central

    Bihl, F; Pena-Rossi, C; Guénet, J L; Brahic, M; Bureau, J F

    1997-01-01

    Theiler's virus persists in the white matter of the spinal cord of genetically susceptible mice and causes primary demyelination. The virus persists in macrophages/microglial cells, but also in oligodendrocytes, the myelin-forming cells. Susceptibility/resistance to this chronic infection has been mapped to several loci including one tentatively located in the telomeric region of chromosome 18, close to the myelin basic protein locus (Mbp locus). To determine if the MBP gene influences viral persistence, we inoculated C3H mice bearing the shiverer mutation, a 20-kb deletion in the gene. Whereas control C3H mice were of intermediate susceptibility, C3H mice heterozygous for the mutation were very susceptible, and those homozygous for the mutation were completely resistant. This resistance was not immune mediated. Furthermore, C3H/101H mice homozygous for a point mutation in the gene coding for the proteolipid protein of myelin, the rumpshaker mutation, were resistant. These results strongly support the view that oligodendrocytes are a necessary viral target for the establishment of a persistent infection by Theiler's virus. PMID:9188567

  2. Two novel mutations affecting splicing in the IRF6 gene associated with van der Woude syndrome.

    PubMed

    Scioletti, Anna Paola; Brancati, Francesco; Gatta, Valentina; Antonucci, Ivana; Peissel, Bernard; Pizzuti, Antonio; Mortellaro, Carmen; Tetè, Stefano; Gherlone, Enrico; Palka, Giandomenico; Stuppia, Liborio

    2010-09-01

    van der Woude syndrome (VWS) is a rare autosomal dominant oral facial disorder characterized by high penetrance and variable expression, manifesting with lower lip pits, cleft lips with or without cleft palate, and isolated cleft palate. The phenotypic expression of clefts ranges from incomplete to complete. Different studies have demonstrated an association between VWS and mutations of the IRF6 (interferon regulatory factor) gene. In this study, we describe 2 novel Italian families with VWS harboring 2 distinct splice site mutations in the IRF6 gene. These results add to the previous 9 splicing mutations identified in patients with VWS and strengthen the importance of this type of alterations in the pathogenesis of the disease. PMID:20856073

  3. fusca3: A Heterochronic Mutation Affecting Late Embryo Development in Arabidopsis.

    PubMed Central

    Keith, K.; Kraml, M.; Dengler, N. G.; McCourt, P.

    1994-01-01

    Molecular studies of late embryogenesis and seed development have emphasized differential gene expression as a means of identifying discrete stages of embryogenesis. Little has been done to identify factors that regulate the length of a given developmental stage or the degree of overlap between adjacent developmental programs. We designed a genetic screen to identify mutations that disrupt late embryo development in Arabidopsis without loss of hormonal responses. One such mutation, fusca3 (fus3), alters late embryo functions, such as the establishment of dormancy and desiccation tolerance, and reduces storage protein levels. fus3 cotyledons bear trichomes, and their ultrastructure is similar to that of leaf primordia. Immature fus3 embryos enter germinative development, and the shoot apical meristems develop leaf primordia before seed desiccation begins. The cotyledons resemble leaf primordia, yet retain some cotyledon characteristics; thus, cotyledon- and leaf-specific functions are expressed simultaneously. Together, these observations are consistent with a heterochronic interpretation of the fus3 mutation. PMID:12244252

  4. A Novel Inducer of Roseobacter Motility Is Also a Disruptor of Algal Symbiosis

    PubMed Central

    Sule, Preeti

    2013-01-01

    Silicibacter sp. strain TM1040, a member of the Roseobacter clade, forms a symbiosis with unicellular phytoplankton, which is inextricably linked to the biphasic “swim or stick” lifestyle of the bacteria. Mutations in flaC bias the population toward the motile phase. Renewed examination of the FlaC− strain (HG1016) uncovered that it is composed of two different cells: a pigmented type, PS01, and a nonpigmented cell, PS02, each of which has an identical mutation in flaC. While monocultures of PS01 and PS02 had few motile cells (0.6 and 6%, respectively), coculturing the two strains resulted in a 10-fold increase in the number of motile cells. Cell-free supernatants from coculture or wild-type cells were fully capable of restoring motility to PS01 and PS02, which was due to increased fliC3 (flagellin) transcription, FliC3 protein levels per cell, and flagella synthesis. The motility-inducing compound has an estimated mass of 226 Da, as determined by mass spectrometry, and is referred to as Roseobacter Motility Inducer (RMI). Mutations affecting genes involved in phenyl acetic acid synthesis significantly reduced RMI, while defects in tropodithietic acid (TDA) synthesis had marginal or no effect on RMI. RMI biosynthesis is induced by p-coumaric acid, a product of algal lignin degradation. When added to algal cultures, RMI caused loss of motility, cell enlargement, and vacuolization in the algal cells. RMI is a new member of the roseobacticide family of troponoid compounds whose activities affect roseobacters, by shifting their population toward motility, as well as their phytoplankton hosts, through an algicidal effect. PMID:23161030

  5. Direct selection for mutations affecting specific splice sites in a hamster dihydrofolate reductase minigene.

    PubMed Central

    Chen, I T; Chasin, L A

    1993-01-01

    A Chinese hamster cell line containing an extra exon 2 (50 bp) inserted into a single intron of a dihydrofolate reductase (dhfr) minigene was constructed. The extra exon 2 was efficiently spliced into the RNA, resulting in an mRNA that is incapable of coding for the DHFR enzyme. Mutations that decreased splicing of this extra exon 2 caused it to be skipped and so produced normal dhfr mRNA. In contrast to the parental cell line, the splicing mutants display a DHFR-positive growth phenotype. Splicing mutants were isolated from this cell line after treatment with four different mutagens (racemic benzo[c]phenanthrene diol epoxide, ethyl methanesulfonate, ethyl nitrosourea, and UV irradiation). By polymerase chain reaction amplification and direct DNA sequencing, we determined the base changes in 66 mutants. Each of the mutagens generated highly specific base changes. All mutations were single-base substitutions and comprised 24 different changes distributed over 16 positions. Most of the mutations were within the consensus sequences at the exon 2 splice donor, acceptor, and branch sites. The RNA splicing patterns in the mutants were analyzed by quantitative reverse transcription-polymerase chain reaction. The recruitment of cryptic sites was rarely seen; simple exon skipping was the predominant mutant phenotype. The wide variety of mutations that produced exon skipping suggests that this phenotype is the typical consequence of splice site damage and supports the exon definition model of splice site selection. A few mutations were located outside the consensus sequences, in the exon or between the branch point and the polypyrimidine tract, identifying additional positions that play a role in splice site definition. That most of these 66 mutations fell within consensus sequences in this near-saturation mutagenesis suggests that splicing signals beyond the consensus may consist of robust RNA structures. Images PMID:8417332

  6. Evolution of symbiosis with resource allocation from fecundity to survival

    NASA Astrophysics Data System (ADS)

    Fukui, Shin

    2014-05-01

    Symbiosis is one of the most fundamental relationships between or among organisms and includes parasitism (which has negative effects on the fitness of the interacting partner), commensalism (no effect), and mutualism (positive effects). The effects of these interactions are usually assumed to influence a single component of a species' fitness, either survival or fecundity, even though in reality the interaction can simultaneously affect both of these components. I used a dual lattice model to investigate the process of evolution of mutualistic symbiosis in the presence of interactive effects on both survival and fecundity. I demonstrate that a positive effect on survival and a negative effect on fecundity are key to the establishment of mutualism. Furthermore, both the parasitic and the mutualistic behaviour must carry large costs for mutualism to evolve. This helps develop a new understanding of symbiosis as a function of resource allocation, in which resources are shifted from fecundity to survival. The simultaneous establishment of mutualism from parasitism never occurs in two species, but can do so in one of the species as long as the partner still behaves parasitically. This suggests that one of the altruistic behaviours in a mutualistic unit consisting of two species must originate as a parasitic behaviour.

  7. Evolution of symbiosis with resource allocation from fecundity to survival.

    PubMed

    Fukui, Shin

    2014-05-01

    Symbiosis is one of the most fundamental relationships between or among organisms and includes parasitism (which has negative effects on the fitness of the interacting partner), commensalism (no effect), and mutualism (positive effects). The effects of these interactions are usually assumed to influence a single component of a species' fitness, either survival or fecundity, even though in reality the interaction can simultaneously affect both of these components. I used a dual lattice model to investigate the process of evolution of mutualistic symbiosis in the presence of interactive effects on both survival and fecundity. I demonstrate that a positive effect on survival and a negative effect on fecundity are key to the establishment of mutualism. Furthermore, both the parasitic and the mutualistic behaviour must carry large costs for mutualism to evolve. This helps develop a new understanding of symbiosis as a function of resource allocation, in which resources are shifted from fecundity to survival. The simultaneous establishment of mutualism from parasitism never occurs in two species, but can do so in one of the species as long as the partner still behaves parasitically. This suggests that one of the altruistic behaviours in a mutualistic unit consisting of two species must originate as a parasitic behaviour.

  8. The Rhizobium-plant symbiosis.

    PubMed Central

    van Rhijn, P; Vanderleyden, J

    1995-01-01

    Rhizobium, Bradyrhizobium, and Azorhizobium species are able to elicit the formation of unique structures, called nodules, on the roots or stems of the leguminous host. In these nodules, the rhizobia convert atmospheric N2 into ammonia for the plant. To establish this symbiosis, signals are produced early in the interaction between plant and rhizobia and they elicit discrete responses by the two symbiotic partners. First, transcription of the bacterial nodulation (nod) genes is under control of the NodD regulatory protein, which is activated by specific plant signals, flavonoids, present in the root exudates. In return, the nod-encoded enzymes are involved in the synthesis and excretion of specific lipooligosaccharides, which are able to trigger on the host plant the organogenic program leading to the formation of nodules. An overview of the organization, regulation, and function of the nod genes and their participation in the determination of the host specificity is presented. PMID:7708010

  9. Chemically Induced Cuticle Mutation Affecting Epidermal Conductance to Water Vapor and Disease Susceptibility in Sorghum bicolor (L.) Moench.

    PubMed Central

    Jenks, M. A.; Joly, R. J.; Peters, P. J.; Rich, P. J.; Axtell, J. D.; Ashworth, E. N.

    1994-01-01

    Analysis of Sorghum bicolor bloomless (bm) mutants with altered epicuticular wax (EW) structure uncovered a mutation affecting both EW and cuticle deposition. The cuticle of mutant bm-22 was about 60% thinner and approximately one-fifth the weight of the wild-type parent P954035 (WT-P954035) cuticles. Reduced cuticle deposition was associated with increased epidermal conductance to water vapor. The reduction in EW and cuticle deposition increased susceptibility to the fungal pathogen Exserohilum turcicum. Evidence suggests that this recessive mutation occurs at a single locus with pleiotropic effects. The independently occurring gene mutations of bm-2, bm-6, bm-22, and bm-33 are allelic. These chemically induced mutants had essentially identical EW structure, water loss, and cuticle deposition. Furthermore, 138 F2 plants from a bm-22 x WT-P954035 backcross showed no recombination of these traits. This unique mutation in a near-isogenic background provides a useful biological system to examine plant cuticle biosynthesis, physiology, and function. PMID:12232280

  10. Interactions between Escherichia coli RNA polymerase and lambda repressor. Mutations in PRM affect repression of PR.

    PubMed

    Hwang, J J; Gussin, G N

    1988-04-20

    The rightward operator, OR, of bacteriophage lambda is part of a complex regulatory region that includes PRM, the promoter for repressor synthesis by a prophage, the rightward early promoter PR, and three repressor-binding sites, OR1, OR2 and OR3. By binding to OR2, repressor blocks transcription from PR and simultaneously stimulates the formation of open complexes between RNA polymerase and PRM. In this letter, we describe a test of the hypothesis that the interaction between RNA polymerase bound at PRM and repressor bound at OR2 increases the apparent affinity of repressor for OR. One implication of this hypothesis is that the amount of repressor required for repression of PR should be inversely correlated with PRM promoter strength. This is indeed the case. The amount of repressor required for 50% repression of PR is decreased by prmup-1, an "up" mutation of PRM, and is increased by prm- mutations. An unexpected finding is that in addition to their effect on the apparent affinity of repressor for OR, mutations in the -35 region of PRM alter the shape of repressor-titration curves. We propose that these mutations alter the interaction between RNA polymerase bound at PRM and repressor bound at OR2 in such a way that cooperativity in the binding of repressor to OR1 and OR2 is also disrupted.

  11. Oncogenic Mutations Differentially Affect Bax Monomer, Dimer, and Oligomeric Pore Formation in the Membrane

    PubMed Central

    Zhang, Mingzhen; Zheng, Jie; Nussinov, Ruth; Ma, Buyong

    2016-01-01

    Dysfunction of Bax, a pro-apoptotic regulator of cellular metabolism is implicated in neurodegenerative diseases and cancer. We have constructed the first atomistic models of the Bax oligomeric pore consisting with experimental residue-residue distances. The models are stable, capturing well double electron-electron resonance (DEER) spectroscopy measurements and provide structural details in line with the DEER data. Comparison with the latest experimental results revealed that our models agree well with both Bax and Bak pores, pointed to a converged structural arrangement for Bax and Bak pore formation. Using multi-scale molecular dynamics simulations, we probed mutational effects on Bax transformation from monomer → dimer → membrane pore formation at atomic resolution. We observe that two cancer-related mutations, G40E and S118I, allosterically destabilize the monomer and stabilize an off-pathway swapped dimer, preventing productive pore formation. This observation suggests a mechanism whereby the mutations may work mainly by over-stabilizing the monomer → dimer transformation toward an unproductive off-pathway swapped-dimer state. Our observations point to misfolded Bax states, shedding light on the molecular mechanism of Bax mutation-elicited cancer. Most importantly, the structure of the Bax pore facilitates future study of releases cytochrome C in atomic detail. PMID:27630059

  12. A mutation affecting carbon catabolite repression suppresses growth defects in pyruvate carboxylase mutants from Saccharomyces cerevisiae.

    PubMed

    Blázquez, M A; Gamo, F J; Gancedo, C

    1995-12-18

    Yeasts with disruptions in the genes PYC1 and PYC2 encoding the isoenzymes of pyruvate carboxylase cannot grow in a glucose-ammonium medium (Stucka et al. (1991) Mol. Gen. Genet. 229, 307-315). We have isolated a dominant mutation, BPC1-1, that allows growth in this medium of yeasts with interrupted PYC1 and PYC2 genes. The BPC1-1 mutation abolishes catabolite repression of a series of genes and allows expression of the enzymes of the glyoxylate cycle during growth in glucose. A functional glyoxylate cycle is necessary for suppression as a disruption of gene ICL1 encoding isocitrate lyase abolished the phenotypic effect of BPC1-1 on growth in glucose-ammonium. Concurrent expression from constitutive promoters of genes ICL1 and MLS1 (encoding malate synthase) also suppressed the growth phenotype of pyc1 pyc2 mutants. The mutation BPC1-1 is either allelic or closely linked to the mutation DGT1-1.

  13. Oncogenic Mutations Differentially Affect Bax Monomer, Dimer, and Oligomeric Pore Formation in the Membrane.

    PubMed

    Zhang, Mingzhen; Zheng, Jie; Nussinov, Ruth; Ma, Buyong

    2016-01-01

    Dysfunction of Bax, a pro-apoptotic regulator of cellular metabolism is implicated in neurodegenerative diseases and cancer. We have constructed the first atomistic models of the Bax oligomeric pore consisting with experimental residue-residue distances. The models are stable, capturing well double electron-electron resonance (DEER) spectroscopy measurements and provide structural details in line with the DEER data. Comparison with the latest experimental results revealed that our models agree well with both Bax and Bak pores, pointed to a converged structural arrangement for Bax and Bak pore formation. Using multi-scale molecular dynamics simulations, we probed mutational effects on Bax transformation from monomer → dimer → membrane pore formation at atomic resolution. We observe that two cancer-related mutations, G40E and S118I, allosterically destabilize the monomer and stabilize an off-pathway swapped dimer, preventing productive pore formation. This observation suggests a mechanism whereby the mutations may work mainly by over-stabilizing the monomer → dimer transformation toward an unproductive off-pathway swapped-dimer state. Our observations point to misfolded Bax states, shedding light on the molecular mechanism of Bax mutation-elicited cancer. Most importantly, the structure of the Bax pore facilitates future study of releases cytochrome C in atomic detail. PMID:27630059

  14. Characterization of novel Brown midrib 6 mutations affecting lignin biosynthesis in sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of lignin reduces the quality of lignocellulosic biomass for forage materials and feedstock for biofuels. In C4 grasses, the brown midrib phenotype has been linked to mutations to genes in the monolignol biosynthesis pathway. For example, the Bmr6 gene in sorghum (Sorghum bicolor) has b...

  15. Regulatory Light Chain Mutations Associated with Cardiomyopathy Affect Myosin Mechanics and Kinetics

    PubMed Central

    Greenberg, Michael J.; Watt, James D.; Jones, Michelle; Kazmierczak, Katarzyna; Szczesna-Cordary, Danuta; Moore, Jeffrey R.

    2009-01-01

    The myosin regulatory light chain (RLC) wraps around the alpha helical neck region of myosin. This neck region has been proposed to act as a lever arm, amplifying small conformational changes in the myosin head to generate motion. The RLC serves an important structural role, supporting the myosin neck region and a modulatory role, tuning the kinetics of the actin myosin interaction. Given the importance of the RLC, it is not surprising that mutations of the RLC can lead to familial hypertrophic cardiomyopathy (FHC), the leading cause of sudden cardiac death in people under 30. Population studies identified two FHC mutations located near the cationic binding site of the RLC, R58Q and N47K. Although these mutations are close in sequence, they differ in clinical presentation and prognosis with R58Q showing a more severe phenotype. We examined the molecular based changes in myosin that are responsible for the disease phenotype by purifying myosin from transgenic mouse hearts expressing mutant myosins and examining actin filament sliding using the in vitro motility assay. We found that both R58Q and N47K showed reductions in force compared to the wild type that could result in compensatory hypertrophy. Furthermore, we observed a higher ATPase rate and an increased activation at submaximal calcium levels for the R58Q myosin that could lead to decreased efficiency and incomplete cardiac relaxation, potentially explaining the more severe phenotype for the R58Q mutation. PMID:18929571

  16. Rich Medium Composition Affects Escherichia coli Survival, Glycation, and Mutation Frequency during Long-Term Batch Culture

    PubMed Central

    Kram, Karin E.

    2015-01-01

    Bacteria such as Escherichia coli are frequently grown to high density to produce biomolecules for study in the laboratory. To achieve this, cells can be incubated in extremely rich media that increase overall cell yield. In these various media, bacteria may have different metabolic profiles, leading to changes in the amounts of toxic metabolites produced. We have previously shown that stresses experienced during short-term growth can affect the survival of cells during the long-term stationary phase (LTSP). Here, we incubated cells in LB, 2× yeast extract-tryptone (YT), Terrific Broth, or Super Broth medium and monitored survival during the LTSP, as well as other reporters of genetic and physiological change. We observe differential cell yield and survival in all media studied. We propose that differences in long-term survival are the result of changes in the metabolism of components of the media that may lead to increased levels of protein and/or DNA damage. We also show that culture pH and levels of protein glycation, a covalent modification that causes protein damage, affect long-term survival. Further, we measured mutation frequency after overnight incubation and observed a correlation between high mutation frequencies at the end of the log phase and loss of viability after 4 days of LTSP incubation, indicating that mutation frequency is potentially predictive of long-term survival. Since glycation and mutation can be caused by oxidative stress, we measured expression of the oxyR oxidative stress regulator during log-phase growth and found that higher levels of oxyR expression during the log phase are consistent with high mutation frequency and lower cell density during the LTSP. Since these complex rich media are often used when producing large quantities of biomolecules in the laboratory, the observed increase in damage resulting in glycation or mutation may lead to production of a heterogeneous population of plasmids or proteins, which could affect the

  17. The DMRT3 'Gait keeper' mutation affects performance of Nordic and Standardbred trotters.

    PubMed

    Jäderkvist, K; Andersson, L S; Johansson, A M; Árnason, T; Mikko, S; Eriksson, S; Andersson, L; Lindgren, G

    2014-10-01

    In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We genotyped 427 Nordic trotters and 621 Standardbreds for the DMRT3 nonsense mutation and a SNP in strong linkage disequilibrium with it. In Nordic trotters, we show that horses homozygous for the DMRT3 mutation (A) had significantly higher EBV for trotting performance traits than heterozygous (CA) or homozygous wild-type (CC) horses (P = 0.001). Furthermore, AA homozygotes had a higher proportion of victories and top 3 placings than horses heterozygous or homozygous wild-type, when analyzing performance data for the period 3 to 6 yr of age (P = 0.06 and P = 0.05, respectively). Another finding in the Nordic trotters was that the DMRT3 mutation influenced trotting technique (P = 2.1 × 10(-8)). Standardbred horses homozygous AA had significantly higher EBV for all traits than horses with at least 1 wild-type allele (CA and CC; P = 1.6 × 10(-16)). In a within-family analysis of Standardbreds, we found significant differences in several traits (e.g., earnings, P = 0.002; number of entered races, P = 0.004; and fraction of offspring that entered races, P = 0.002) among paternal half-sibs with genotype AA or CA sired by a CA stallion. For most traits, we found significant differences at young ages. For Nordic trotters, most of the results were significant at 3 yr of age but not for the older ages, and for the Standardbreds most of the results for the ages 3 to 5 were significant. For

  18. The DMRT3 'Gait keeper' mutation affects performance of Nordic and Standardbred trotters.

    PubMed

    Jäderkvist, K; Andersson, L S; Johansson, A M; Árnason, T; Mikko, S; Eriksson, S; Andersson, L; Lindgren, G

    2014-10-01

    In a previous study it was shown that a nonsense mutation in the DMRT3 gene alters the pattern of locomotion in horses and that this mutation has a strong positive impact on trotting performance of Standardbreds. One aim of this study was to test if racing performance and trotting technique in the Nordic (Coldblood) trotters are also influenced by the DMRT3 genotype. Another aim was to further investigate the effect of the mutation on performance in Standardbreds, by using a within-family analysis and genotype-phenotype correlations in a larger horse material than in the previous study. We genotyped 427 Nordic trotters and 621 Standardbreds for the DMRT3 nonsense mutation and a SNP in strong linkage disequilibrium with it. In Nordic trotters, we show that horses homozygous for the DMRT3 mutation (A) had significantly higher EBV for trotting performance traits than heterozygous (CA) or homozygous wild-type (CC) horses (P = 0.001). Furthermore, AA homozygotes had a higher proportion of victories and top 3 placings than horses heterozygous or homozygous wild-type, when analyzing performance data for the period 3 to 6 yr of age (P = 0.06 and P = 0.05, respectively). Another finding in the Nordic trotters was that the DMRT3 mutation influenced trotting technique (P = 2.1 × 10(-8)). Standardbred horses homozygous AA had significantly higher EBV for all traits than horses with at least 1 wild-type allele (CA and CC; P = 1.6 × 10(-16)). In a within-family analysis of Standardbreds, we found significant differences in several traits (e.g., earnings, P = 0.002; number of entered races, P = 0.004; and fraction of offspring that entered races, P = 0.002) among paternal half-sibs with genotype AA or CA sired by a CA stallion. For most traits, we found significant differences at young ages. For Nordic trotters, most of the results were significant at 3 yr of age but not for the older ages, and for the Standardbreds most of the results for the ages 3 to 5 were significant. For

  19. A mutation in the aroE gene affects pigment production, virulence, and chemotaxis in Xanthomonas oryzae pv. oryzae.

    PubMed

    Kim, Hong-Il; Noh, Tae-Hwan; Lee, Chang-Soo; Park, Young-Jin

    2015-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB) in rice. To study its function, a random insertion mutation library of Xoo was constructed using the Tn5 transposon. A mutant strain with decreased virulence against the susceptible rice cultivar IR24 was isolated from the library (aroE mutant), which also had extremely low pigment production. Thermal asymmetric interlaced-polymerase chain reaction (TAIL-PCR) and sequence analysis of the mutant revealed that the transposon was inserted into the aroE gene (encoding shikimate dehydrogenase). To investigate gene expression changes in the pigment- and virulence-deficient mutant, DNA microarray analysis was performed, which showed downregulation of 20 genes involved in the chemotaxis of Xoo. Our findings reveal that mutation of the aroE gene affects virulence and pigment production, as well as expression of genes involved in Xoo chemotaxis.

  20. Mutated otopetrin 1 affects the genesis of otoliths and the localization of Starmaker in zebrafish.

    PubMed

    Söllner, Christian; Schwarz, Heinz; Geisler, Robert; Nicolson, Teresa

    2004-12-01

    Otoliths in bony fishes and otoconia in mammals are composite crystals consisting of calcium carbonate and proteins. These biominerals are part of the gravity and linear acceleration detection system of the inner ear. Mutations in otopetrin 1 have been shown to result in lack of otoconia in tilted and mergulhador mutant mice. The molecular function of Otopetrin 1, a novel protein that contains ten predicted transmembrane domains, however, has remained elusive. Here we show that a mutation in the orthologous gene in zebrafish is responsible for the complete absence of otoliths in backstroke mutants. We examined the localization of Starmaker, a secreted protein that is highly abundant in otoliths in backstroke mutants. Starmaker protein accumulated within cells of the otic epithelium, indicating a possible defect in secretion. Our data suggest that Otopetrin 1 in zebrafish may be involved in the protein trafficking of components required for formation of biominerals in the ear. PMID:15480759

  1. Transient congenital hypothyroidism caused by compound heterozygous mutations affecting the NADPH-oxidase domain of DUOX2.

    PubMed

    Yoshizawa-Ogasawara, Atsuko; Abe, Kiyomi; Ogikubo, Sayaka; Narumi, Satoshi; Hasegawa, Tomonobu; Satoh, Mari

    2016-03-01

    Here, we describe three cases of loss-of-function mutations in the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase (NOX) domain of dual oxidase 2 (DUOX2) occurring along with concurrent missense mutations in thyroid peroxidase (TPO), leading to transient congenital hypothyroidism (CH). Three Japanese boys with nonconsanguineous parents were diagnosed with CH during their neonatal screenings. All patients presented with moderate-to-severe neonatal hypothyroidism and were diagnosed with transient CH after re-evaluation of thyroid function. Two siblings were compound heterozygous for p.[R1110Q]+[Y1180X] in DUOX2; one of them was also heterozygous for p.[R361L] in TPO. The third patient was compound heterozygous for p.[L1160del]+[R1334W] in DUOX2 and heterozygous for p.[P883S] in TPO. This is the first report of a de novo L1160del mutation affecting the DUOX2 gene and of the novel mutations Y1180X in DUOX2 and R361L in TPO. R1110Q and L1160del were found to reduce H2O2 production (5%-9%, p<0.01), while Y1180X, which introduces a premature stop codon, did not confer detectable H2O2 production (-0.7%±0.6%, p<0.01). Moreover, R1334W, a missense mutation possibly affecting electron transfer, led to reduced H2O2 production (24%±0.9%, p<0.01) in vitro, and R1110Q and R1334W resulted in reduced protein expression. Y1180X was detected in a 120 kDa truncated form, whereas L1160del expression was maintained. Further, R361L, a novel missense mutation in TPO, caused partial reduction in peroxidase activity (20.6%±0.8%, p=0.01), whereas P883S, a missense variant, increased it (133.7%±2.8%, p=0.02). The protein expression levels in the case of R361L and P883S were maintained. In conclusion, we provide clinical and in vitro demonstrations of different functional defects and phenotypic heterogeneity in the same thyroid hormonogenesis pathway.

  2. Colon cancer metastasis in mouse liver is not affected by hypercoagulability due to Factor V Leiden mutation

    PubMed Central

    Klerk, CPW; Smorenburg, SM; Spek, CA; Van Noorden, CJF

    2007-01-01

    Abstract Clinical trials have shown life-prolonging effects of antithrombotics in cancer patients, but the molecular mechanisms remain unknown due to the multitude of their effects. We investigated in a mouse model whether one of the targets of antithrombotic therapy, fibrin deposition, stimulates tumour development. Fibrin may provide either protection of cancer cells in the circulation against mechanical stress and the immune system, or form a matrix for tumours and/or angiogenesis in tumours to develop. Mice homozygous for Factor V Leiden (FVL), a mutation in one of the coagulation factors that facilitates fibrin formation, were used to investigate whether hypercoagulability affects tumour development in an experimental metastasis model. Liver metastases of colon cancer were induced in mice with the FVL mutation and wild-type littermates. At day 21, number and size of tumours at the liver surface, fibrin/fibrinogen distribution, vessel density and the presence of newly formed vessels in tumours were analysed. Number and size of tumours did not differ between mice with and without the FVL mutation. Fibrin/fibrinogen was found in the cytoplasm of hepatocytes and cancer cells, in blood vessels in liver and tumour tissue and diffusely distributed outside vessels in tumours, indicating leaky vessels. Vessel density and angiogenesis varied widely between tumours, but a pre-dominance for vessel-rich or vessel-poor tumours or vessel formation could not be found in either genotype. In conclusion, the FVL mutation has no effect on the development of secondary tumours of colon cancer in livers of mice. Fibrin deposition and thus inhibition of fibrin formation by anticoagulants do not seem to affect tumour development in this model. PMID:17635646

  3. Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

    PubMed Central

    Alsafadi, Samar; Houy, Alexandre; Battistella, Aude; Popova, Tatiana; Wassef, Michel; Henry, Emilie; Tirode, Franck; Constantinou, Angelos; Piperno-Neumann, Sophie; Roman-Roman, Sergio; Dutertre, Martin; Stern, Marc-Henri

    2016-01-01

    Hotspot mutations in the spliceosome gene SF3B1 are reported in ∼20% of uveal melanomas. SF3B1 is involved in 3′-splice site (3′ss) recognition during RNA splicing; however, the molecular mechanisms of its mutation have remained unclear. Here we show, using RNA-Seq analyses of uveal melanoma, that the SF3B1R625/K666 mutation results in deregulated splicing at a subset of junctions, mostly by the use of alternative 3′ss. Modelling the differential junctions in SF3B1WT and SF3B1R625/K666 cell lines demonstrates that the deregulated splice pattern strictly depends on SF3B1 status and on the 3'ss-sequence context. SF3B1WT knockdown or overexpression do not reproduce the SF3B1R625/K666 splice pattern, qualifying SF3B1R625/K666 as change-of-function mutants. Mutagenesis of predicted branchpoints reveals that the SF3B1R625/K666-promoted splice pattern is a direct result of alternative branchpoint usage. Altogether, this study provides a better understanding of the mechanisms underlying splicing alterations induced by mutant SF3B1 in cancer, and reveals a role for alternative branchpoints in disease. PMID:26842708

  4. Mutations in Durum Wheat SBEII Genes affect Grain Yield Components, Quality, and Fermentation Responses in Rats

    PubMed Central

    Hazard, Brittany; Zhang, Xiaoqin; Naemeh, Mahmoudreza; Hamilton, M. Kristina; Rust, Bret; Raybould, Helen E.; Newman, John W.; Martin, Roy; Dubcovsky, Jorge

    2016-01-01

    Increased amylose in wheat (Triticum ssp.) starch is associated with increased resistant starch, a fermentable dietary fiber. Fermentation of resistant starch in the large intestine produces short-chain fatty acids that are associated with human health benefits. Since wheat foods are an important component of the human diet, increases in amylose and resistant starch in wheat grains have the potential to deliver health benefits to a large number of people. In three replicated field trials we found that mutations in starch branching enzyme II genes (SBEIIa and SBEIIb) in both A and B genomes (SBEIIa/b-AB) of durum wheat [T. turgidum L. subsp. durum (Desf.) Husn.] resulted in large increases of amylose and resistant starch content. The presence of these four mutations was also associated with an average 5% reduction in kernel weight (P = 0.0007) and 15% reduction in grain yield (P = 0.06) compared to the wild type. Complete milling and pasta quality analysis showed that the mutant lines have an acceptable quality with positive effects on pasta firmness and negative effects on semolina extraction and pasta color. Positive fermentation responses were detected in rats (Rattus spp.) fed with diets incorporating mutant wheat flour. This study quantifies benefits and limitations associated with the deployment of the SBEIIa/b-AB mutations in durum wheat and provides the information required to develop realistic strategies to deploy durum wheat varieties with increased levels of amylose and resistant starch. PMID:27134286

  5. Myotonia Congenita-Associated Mutations in Chloride Channel-1 Affect Zebrafish Body Wave Swimming Kinematics

    PubMed Central

    Cheng, Wei; Tian, Jing; Burgunder, Jean-Marc; Hunziker, Walter; Eng, How-Lung

    2014-01-01

    Myotonia congenita is a human muscle disorder caused by mutations in CLCN1, which encodes human chloride channel 1 (CLCN1). Zebrafish is becoming an increasingly useful model for human diseases, including muscle disorders. In this study, we generated transgenic zebrafish expressing, under the control of a muscle specific promoter, human CLCN1 carrying mutations that have been identified in human patients suffering from myotonia congenita. We developed video analytic tools that are able to provide precise quantitative measurements of movement abnormalities in order to analyse the effect of these CLCN1 mutations on adult transgenic zebrafish swimming. Two new parameters for body-wave kinematics of swimming reveal changes in body curvature and tail offset in transgenic zebrafish expressing the disease-associated CLCN1 mutants, presumably due to their effect on muscle function. The capability of the developed video analytic tool to distinguish wild-type from transgenic zebrafish could provide a useful asset to screen for compounds that reverse the disease phenotype, and may be applicable to other movement disorders besides myotonia congenita. PMID:25083883

  6. Mild mutations in the pan neural gene prospero affect male-specific behaviour in Drosophila melanogaster.

    PubMed

    Grosjean, Yaël; Savy, Mathilde; Soichot, Julien; Everaerts, Claude; Cézilly, Frank; Ferveur, Jean François

    2004-01-30

    The fruitfly Drosophila melanogaster is one of the most appropriate model organisms to study the genetics of behaviour. Here, we focus on prospero (pros), a key gene for the development of the nervous system which specifies multiple aspects from the early formation of the embryonic central nervous system to the formation of larval and adult sensory organs. We studied the effects on locomotion, courtship and mating behaviour of three mild pros mutations. These newly isolated pros mutations were induced after the incomplete excision of a transposable genomic element that, before excision, caused a lethal phenotype during larval development. Strikingly, these mutant strains, but not the strains with a clean excision, produced a high frequency of heterozygous flies, after more than 50 generations in the lab. We investigated the factors that could decrease the fitness of homozygotes relatively to heterozygous pros mutant flies. Flies of both genotypes had slightly different levels of fertility. More strikingly, homozygous mutant males had a lower sexual activity than heterozygous males and failed to mate in a competitive situation. No similar effect was detected in mutant females. These findings suggest that mild mutations in pros did not alter vital functions during development but drastically changed adult male behaviour and reproductive fitness. PMID:14744542

  7. Mutations in DMRT3 affect locomotion in horses and spinal circuit function in mice.

    PubMed

    Andersson, Lisa S; Larhammar, Martin; Memic, Fatima; Wootz, Hanna; Schwochow, Doreen; Rubin, Carl-Johan; Patra, Kalicharan; Arnason, Thorvaldur; Wellbring, Lisbeth; Hjälm, Göran; Imsland, Freyja; Petersen, Jessica L; McCue, Molly E; Mickelson, James R; Cothran, Gus; Ahituv, Nadav; Roepstorff, Lars; Mikko, Sofia; Vallstedt, Anna; Lindgren, Gabriella; Andersson, Leif; Kullander, Klas

    2012-08-30

    Locomotion in mammals relies on a central pattern-generating circuitry of spinal interneurons established during development that coordinates limb movement. These networks produce left-right alternation of limbs as well as coordinated activation of flexor and extensor muscles. Here we show that a premature stop codon in the DMRT3 gene has a major effect on the pattern of locomotion in horses. The mutation is permissive for the ability to perform alternate gaits and has a favourable effect on harness racing performance. Examination of wild-type and Dmrt3-null mice demonstrates that Dmrt3 is expressed in the dI6 subdivision of spinal cord neurons, takes part in neuronal specification within this subdivision, and is critical for the normal development of a coordinated locomotor network controlling limb movements. Our discovery positions Dmrt3 in a pivotal role for configuring the spinal circuits controlling stride in vertebrates. The DMRT3 mutation has had a major effect on the diversification of the domestic horse, as the altered gait characteristics of a number of breeds apparently require this mutation.

  8. A new Gsdma3 mutation affecting anagen phase of first hair cycle

    SciTech Connect

    Tanaka, Shigekazu; Tamura, Masaru; Aoki, Aya; Fujii, Tomoaki; Komiyama, Hiromitsu; Sagai, Tomoko; Shiroishi, Toshihiko . E-mail: tshirois@lab.nig.ac.jp

    2007-08-10

    Recombination-induced mutation 3 (Rim3) is a spontaneous mouse mutation that exhibits dominant phenotype of hyperkeratosis and hair loss. Fine linkage analysis of Rim3 and sequencing revealed a novel single point mutation, G1124A leading to Ala348Thr, in Gsdma3 in chromosome 11. Transgenesis with BAC DNA harboring the Rim3-type Gsdma3 recaptured the Rim3 phenotype, providing direct evidence that Gsdma3 is the causative gene of Rim3. We examined the spatial expression of Gsdma3 and characterized the Rim3 phenotype in detail. Gsdma3 is expressed in differentiated epidermal cells in the skin, but not in the proliferating epidermal cells. Histological analysis of Rim3 mutant showed hyperplasia of the epidermal cells in the upper hair follicles and abnormal anagen phase at the first hair cycle. Furthermore, immunohistochemical analysis revealed hyperproliferation and misdifferentiation of the upper follicular epidermis in Rim3 mutant. These results suggest that Gsdma3 is involved in the proliferation and differentiation of epidermal stem cells.

  9. Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole

    PubMed Central

    Bennett, Gordon M.; Moran, Nancy A.

    2015-01-01

    Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host–symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host–pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid–Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils. PMID:25713367

  10. Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole.

    PubMed

    Bennett, Gordon M; Moran, Nancy A

    2015-08-18

    Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host-symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host-pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid-Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.

  11. Hemoglobin LjGlb1-1 is involved in nodulation and regulates the level of nitric oxide in the Lotus japonicus–Mesorhizobium loti symbiosis

    PubMed Central

    Fukudome, Mitsutaka; Calvo-Begueria, Laura; Kado, Tomohiro; Osuki, Ken-ichi; Rubio, Maria Carmen; Murakami, Ei-ichi; Nagata, Maki; Kucho, Ken-ichi; Sandal, Niels; Stougaard, Jens; Becana, Manuel; Uchiumi, Toshiki

    2016-01-01

    Leghemoglobins transport and deliver O2 to the symbiosomes inside legume nodules and are essential for nitrogen fixation. However, the roles of other hemoglobins (Hbs) in the rhizobia–legume symbiosis are unclear. Several Lotus japonicus mutants affecting LjGlb1-1, a non-symbiotic class 1 Hb, have been used to study the function of this protein in symbiosis. Two TILLING alleles with single amino acid substitutions (A102V and E127K) and a LORE1 null allele with a retrotransposon insertion in the 5′-untranslated region (96642) were selected for phenotyping nodulation. Plants of all three mutant lines showed a decrease in long infection threads and nodules, and an increase in incipient infection threads. About 4h after inoculation, the roots of mutant plants exhibited a greater transient accumulation of nitric oxide (NO) than did the wild-type roots; nevertheless, in vitro NO dioxygenase activities of the wild-type, A102V, and E127K proteins were similar, suggesting that the mutated proteins are not fully functional in vivo. The expression of LjGlb1-1, but not of the other class 1 Hb of L. japonicus (LjGlb1-2), was affected during infection of wild-type roots, further supporting a specific role for LjGlb1-1. In conclusion, the LjGlb1-1 mutants reveal that this protein is required during rhizobial infection and regulates NO levels. PMID:27443280

  12. Suppressors of a genetic regulatory mutation affecting isoleucine-valine biosynthesis in Escherichia coli K-12.

    PubMed Central

    Hahn, J E; Calhoun, D H

    1978-01-01

    Escherichia coli K-12 mutant PS187 carries a mutation, ilvA538, in the structural gene for the biosynthetic L-threonine deaminase that leads to a leucine-sensitive growth phenotype, an isoleucine- and leucine-hypersensitive L-threonine deaminase, and pleiotropic effects resulting in abnormally low and invariant expression of some of the isoleucine-valine biosynthetic enzymes. Fifty-eight derivatives of strain PS187 were isolated as resistant to growth inhibition by leucine, by valine, or by valine plus glycly-valine and were biochemically, genetically, and physiologically characterized. All of these derivatives produced the feedback-hypersensitive L-threonine deaminase, and thus presumably possess the ilvA538 allele of the parent strain. Elevated synthesis of L-threonine deaminase was observed in 41 of the 58 isolates. Among 18 strains analyzed genetically, only those with mutations linked to the ilv gene clusters at 83 min produced elevated levels of L-threonine deaminase. One of the strains, MSR91, isolated as resistant to valine plus glycyl-valine, was chosen for more detailed study. The locus in strain MSR91 conferring resistance was located in four factor crosses between ilvE and rbs, and is in or near the ilvO gene postulated to be a site controlling the expression of the ilvEDA genes. Synthesis of the ilvEDA gene products in strain MSR91 is constitutive and derepressed approximately 200-fold relative to the parent strain, indicating that the genetic regulatory effects of the ilvA538 allele have been suppressed. Strain MSR91 should be suitable for use in purification of the ilvA538 gene product, since enzyme synthesis is fully derepressed and the suppressor mutation is clearly not located within the ilvA gene. PMID:361682

  13. A novel COL11A1 mutation affecting splicing in a patient with Stickler syndrome

    PubMed Central

    Kohmoto, Tomohiro; Naruto, Takuya; Kobayashi, Haruka; Watanabe, Miki; Okamoto, Nana; Masuda, Kiyoshi; Imoto, Issei; Okamoto, Nobuhiko

    2015-01-01

    Stickler syndrome is a clinically and genetically heterogeneous collagenopathy characterized by ocular, auditory, skeletal and orofacial abnormalities, commonly occurring as an autosomal dominant trait. We conducted target resequencing to analyze candidate genes associated with known clinical phenotypes from a 4-year-old girl with Stickler syndrome. We detected a novel heterozygous intronic mutation (NM_001854.3:c.3168+5G>A) in COL11A1 that may impair splicing, which was suggested by in silico prediction and a minigene assay. PMID:27081549

  14. Mutations altering the gammaretrovirus endoproteolytic motif affect glycosylation of the envelope glycoprotein and early events of the virus life cycle

    SciTech Connect

    Argaw, Takele; Wilson, Carolyn A.

    2015-01-15

    Previously, we found that mutation of glutamine to proline in the endoproteolytic cleavage signal of the PERV-C envelope (RQKK to RPKK) resulted in non-infectious vectors. Here, we show that RPKK results in a non-infectious vector when placed in not only a PERV envelope, but also the envelope of a related gammaretrovirus, FeLV-B. The amino acid substitutions do not prevent envelope precursor cleavage, viral core and genome assembly, or receptor binding. Rather, the mutations result in the formation of hyperglycosylated glycoprotein and a reduction in the reverse transcribed minus strand synthesis and undetectable 2-LTR circular DNA in cells exposed to vectors with these mutated envelopes. Our findings suggest novel functions associated with the cleavage signal sequence that may affect trafficking through the glycosylation machinery of the cell. Further, the glycosylation status of the envelope appears to impact post-binding events of the viral life cycle, either membrane fusion, internalization, or reverse transcription. - Highlights: • Env cleavage signal impacts infectivity of gammaretroviruses. • Non-infectious mutants have hyper-glycosylated envelope that bind target cells. • Non-infectious mutants have defects in the formation of the double-stranded DNA. • Env cleavage motif has functions beyond cleavage of the env precursor.

  15. A novel natural mutation AαPhe98Ile in the fibrinogen coiled-coil affects fibrinogen function.

    PubMed

    Riedelová-Reicheltová, Zuzana; Kotlín, Roman; Suttnar, Jiří; Geierová, Véra; Riedel, Tomáš; Májek, Pavel; Dyr, Jan Evangelista

    2014-01-01

    The aim of this study was to investigate the structure and function of fibrinogen obtained from a patient with normal coagulation times and idiopathic thrombophilia. This was done by SDS-PAGE and DNA sequence analyses, scanning electron microscopy, fibrinopeptide release, fibrin polymerisation initiated by thrombin and reptilase, fibrinolysis, and platelet aggregometry. A novel heterozygous point mutation in the fibrinogen Aα chain, Phe98 to Ile, was found and designated as fibrinogen Vizovice. The mutation, which is located in the RGDF sequence (Aα 95-98) of the fibrinogen coiled-coil region, significantly affected fibrin clot morphology. Namely, the clot formed by fibrinogen Vizovice contained thinner and curled fibrin fibers with reduced length. Lysis of the clots prepared from Vizovice plasma and isolated fibrinogen were found to be impaired. The lysis rate of Vizovice clots was almost four times slower than the lysis rate of control clots. In the presence of platelets agonists the mutant fibrinogen caused increased platelet aggregation. The data obtained show that natural mutation of Phe98 to Ile in the fibrinogen Aα chain influences lateral aggregation of fibrin protofibrils, fibrinolysis, and platelet aggregation. They also suggest that delayed fibrinolysis, together with the abnormal fibrin network morphology and increased platelet aggregation, may be the direct cause of thrombotic complications in the patient associated with pregnancy loss. PMID:24108601

  16. Cell surface fucosylation does not affect development of colon tumors in mice with germline Smad3 mutation

    PubMed Central

    Domino, Steven E.; Karnak, David M.; Hurd, Elizabeth A.

    2006-01-01

    Background/Aims: Neoplasia-related alterations in cell surface α(1,2)fucosylated glycans have been reported in multiple tumors including colon, pancreas, endometrium, cervix, bladder, lung, and choriocarcinoma. Spontaneous colorectal tumors from mice with a germline null mutation of transforming growth factor-β signaling gene Smad3 (Madh3) were tested for α(1,2)fucosylated glycan expression. Methods: Ulex Europaeus Agglutinin-I lectin staining, fucosyltransferase gene northern blot analysis, and a cross of mutant mice with Fut2 and Smad3 germline mutations were performed. Results: Spontaneous colorectal tumors from Smad3 (-/-) homozygous null mice were found to express α(1,2)fucosylated glycans in an abnormal pattern compared to adjacent nonneoplastic colon. Northern blot analysis of α(1,2)fucosyltransferase genes Fut1 and Fut2 revealed that Fut2, but not Fut1, steady-state mRNA levels were significantly increased in tumors relative to adjacent normal colonic mucosa. Mutant mice with a Fut2-inactivating germline mutation were crossed with Smad3 targeted mice. In Smad3 (-/-)/Fut2 (-/-) double knock-out mice, UEA-I lectin staining was eliminated from colon and colon tumors, however, the number and size of tumors present by 24 weeks of age did not vary regardless of the Fut2 genotype. Conclusions: In this model of colorectal cancer, cell surface α(1,2)fucosylation does not affect development of colon tumors. PMID:17264540

  17. pigk Mutation underlies macho behavior and affects Rohon-Beard cell excitability

    PubMed Central

    Carmean, V.; Yonkers, M. A.; Tellez, M. B.; Willer, J. R.; Willer, G. B.; Gregg, R. G.; Geisler, R.; Neuhauss, S. C.

    2015-01-01

    The study of touch-evoked behavior allows investigation of both the cells and circuits that generate a response to tactile stimulation. We investigate a touch-insensitive zebrafish mutant, macho (maco), previously shown to have reduced sodium current amplitude and lack of action potential firing in sensory neurons. In the genomes of mutant but not wild-type embryos, we identify a mutation in the pigk gene. The encoded protein, PigK, functions in attachment of glycophosphatidylinositol anchors to precursor proteins. In wild-type embryos, pigk mRNA is present at times when mutant embryos display behavioral phenotypes. Consistent with the predicted loss of function induced by the mutation, knock-down of PigK phenocopies maco touch insensitivity and leads to reduced sodium current (INa) amplitudes in sensory neurons. We further test whether the genetic defect in pigk underlies the maco phenotype by overexpressing wild-type pigk in mutant embryos. We find that ubiquitous expression of wild-type pigk rescues the touch response in maco mutants. In addition, for maco mutants, expression of wild-type pigk restricted to sensory neurons rescues sodium current amplitudes and action potential firing in sensory neurons. However, expression of wild-type pigk limited to sensory cells of mutant embryos does not allow rescue of the behavioral touch response. Our results demonstrate an essential role for pigk in generation of the touch response beyond that required for maintenance of proper INa density and action potential firing in sensory neurons. PMID:26133798

  18. ECHS1 mutations in Leigh disease: a new inborn error of metabolism affecting valine metabolism.

    PubMed

    Peters, Heidi; Buck, Nicole; Wanders, Ronald; Ruiter, Jos; Waterham, Hans; Koster, Janet; Yaplito-Lee, Joy; Ferdinandusse, Sacha; Pitt, James

    2014-11-01

    Two siblings with fatal Leigh disease had increased excretion of S-(2-carboxypropyl)cysteine and several other metabolites that are features of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) deficiency, a rare defect in the valine catabolic pathway associated with Leigh-like disease. However, this diagnosis was excluded by HIBCH sequencing and normal enzyme activity. In contrast to HIBCH deficiency, the excretion of 3-hydroxyisobutyryl-carnitine was normal in the children, suggesting deficiency of short-chain enoyl-CoA hydratase (ECHS1 gene). This mitochondrial enzyme is active in several metabolic pathways involving fatty acids and amino acids, including valine, and is immediately upstream of HIBCH in the valine pathway. Both children were compound heterozygous for a c.473C > A (p.A158D) missense mutation and a c.414+3G>C splicing mutation in ECHS1. ECHS1 activity was markedly decreased in cultured fibroblasts from both siblings, ECHS1 protein was undetectable by immunoblot analysis and transfection of patient cells with wild-type ECHS1 rescued ECHS1 activity. The highly reactive metabolites methacrylyl-CoA and acryloyl-CoA accumulate in deficiencies of both ECHS1 and HIBCH and are probably responsible for the brain pathology in both disorders. Deficiency of ECHS1 or HIBCH should be considered in children with Leigh disease. Urine metabolite testing can detect and distinguish between these two disorders.

  19. Yeast killer plasmid mutations affecting toxin secretion and activity and toxin immunity function

    SciTech Connect

    Bussey, H.; Sacks, W.; Galley, D.; Saville, D.

    1982-04-01

    M double-stranded RNA (MdsRNA) plasmid mutants were obtained by mutagenesis and screening of a diploid killer culture partially heat cured of the plasmid, so that a high proportion of the cells could be expected to have only one M plasmid. Mutants with neutral (K/sup -/), immune (R/sup +/) or suicide (killer (K/sup +/), sensitive (R/sup -/)) phenotypes were examined. All mutants became K/sup -/ R/sup -/ sensitives on heat curing of the MdsRNA plasmid, and showed cytoplasmic inheritance by random spore analysis. In some cases, M plasmid mutations were indicated by altered mobility of the MdsRNA by agarose gel electrophoresis or by altered size of in vitro translation products from denatured dsRNA. Neutral mutants were of two types: nonsecretors of the toxin protein or secretors of an inactive toxin. Of three neutral nonsecretors examined, one (NLP-1), probably a nonsense mutation, made a smaller protoxin precursor in vitro and in vivo, and two made full-size protoxin molecules. The in vivo protoxin of 43,000 molecular weight was unstable in the wild type and kinetically showed a precursor product relationship to the processed, secreted 11,000-molecular-weight toxin. In one nonsecretor (N1), the protoxin appeared more stable in a pulse-chase experiment, and could be altered in a recognition site required for protein processing.

  20. Mutation affecting the expression of immunoglobulin variable regions in the rabbit.

    PubMed

    Kelus, A S; Weiss, S

    1986-07-01

    We have found a variant of the allotype allele a2 in the rabbit, which presumably arose by mutation, that segregates as expected for an allele at the a locus. This allele is called "ali" and the corresponding rabbit strain is called "Alicia." In heterozygous animals (ali/a1 and ali/a3) the concentration of a2 molecules is lower by a factor of 1000 than in standard a2/a2 homozygotes. In homozygous ali/ali individuals the a2 concentration varies with age--i.e., very low in young rabbits and higher in older ones--but it never reaches normal levels. The low level of a2 is compensated by increased amounts of a-negative molecules. Southern blot analysis did not reveal any gross changes in the intron between JH and C mu (joining region of immunoglobulin heavy chain and constant region of immunoglobulin mu chain) or in the number of VH gene segments encoding a locus specificities. We suggest that the ali phenotype is due to a mutation in a control element.

  1. Human mutations affect the epigenetic/bookmarking function of HNF1B

    PubMed Central

    Lerner, Jonathan; Bagattin, Alessia; Verdeguer, Francisco; Makinistoglu, Munevver P.; Garbay, Serge; Felix, Tristan; Heidet, Laurence; Pontoglio, Marco

    2016-01-01

    Bookmarking factors are transcriptional regulators involved in the mitotic transmission of epigenetic information via their ability to remain associated with mitotic chromatin. The mechanisms through which bookmarking factors bind to mitotic chromatin remain poorly understood. HNF1β is a bookmarking transcription factor that is frequently mutated in patients suffering from renal multicystic dysplasia and diabetes. Here, we show that HNF1β bookmarking activity is impaired by naturally occurring mutations found in patients. Interestingly, this defect in HNF1β mitotic chromatin association is rescued by an abrupt decrease in temperature. The rapid relocalization to mitotic chromatin is reversible and driven by a specific switch in DNA-binding ability of HNF1β mutants. Furthermore, we demonstrate that importin-β is involved in the maintenance of the mitotic retention of HNF1β, suggesting a functional link between the nuclear import system and the mitotic localization/translocation of bookmarking factors. Altogether, our studies have disclosed novel aspects on the mechanisms and the genetic programs that account for the mitotic association of HNF1β, a bookmarking factor that plays crucial roles in the epigenetic transmission of information through the cell cycle. PMID:27229139

  2. Mutations in eukaryotic 18S ribosomal RNA affect translational fidelity and resistance to aminoglycoside antibiotics.

    PubMed

    Chernoff, Y O; Vincent, A; Liebman, S W

    1994-02-15

    Mutations have been created in the Saccharomyces cerevisiae 18S rRNA gene that correspond to those known to be involved in the control of translational fidelity or antibiotic resistance in prokaryotes. Yeast strains, in which essentially all chromosomal rDNA repeats are deleted and all cellular rRNAs are encoded by plasmid, have been constructed that contain only mutant 18S rRNA. In Escherichia coli, a C-->U substitution at position 912 of the small subunit rRNA causes streptomycin resistance. Eukaryotes normally carry U at the corresponding position and are naturally resistant to streptomycin. We show that a U-->C transition (rdn-4) at this position of the yeast 18S rRNA gene decreases resistance to streptomycin. The rdn-4 mutation also increases resistance to paromomycin and G-418, and inhibits nonsense suppression induced by paromomycin. The same phenotypes, as well as a slow growth phenotype, are also associated with rdn-2, whose prokaryotic counterpart, 517 G-->A, manifests itself as a suppressor rather than an antisuppressor. Neither rdn-2- nor rdn-4-related phenotypes could be detected in the presence of the normal level of wild-type rDNA repeats. Our data demonstrate that eukaryotic rRNA is involved in the control of translational fidelity, and indicate that rRNA features important for interactions with aminoglycosides have been conserved throughout evolution.

  3. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Garbers, C.; DeLong, A.; Deruere, J.; Bernasconi, P.; Soll, D.; Evans, M. L. (Principal Investigator)

    1996-01-01

    The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis.

  4. Hotfoot mouse mutations affect the delta 2 glutamate receptor gene and are allelic to lurcher.

    PubMed

    Lalouette, A; Guénet, J L; Vriz, S

    1998-05-15

    Hotfoot (ho) is a recessive mouse mutation characterized by cerebellar ataxia associated with relatively mild abnormalities of the cerebellum. It has been previously mapped to Chromosome 6, and at least eight independent alleles have been reported. Here we show that the hotfoot phenotype is associated with mutations in the glutamate receptor ionotropic delta2 gene (Grid2). We have identified a 510-bp deletion in the Grid2 coding sequence in the ho4J allele, resulting in a deletion of 170 amino acids of the extracellular domain of the receptor. Analysis of a second allele, hoTgN37INRA, revealed a 4-kb deletion in the Grid2 transcript. The GRID2 protein in these hotfoot mutants probably has a reduced (or null) activity since the phenotype of hotfoot bears similarities with the previously described phenotype of Grid2 knockout mice. The exceptionally high number of independent alleles at the ho locus is an invaluable tool for investigating the function of the glutamate receptor ionotropic delta2 protein, which so far remains largely unknown.

  5. Ocean acidification alters fish-jellyfish symbiosis.

    PubMed

    Nagelkerken, Ivan; Pitt, Kylie A; Rutte, Melchior D; Geertsma, Robbert C

    2016-06-29

    Symbiotic relationships are common in nature, and are important for individual fitness and sustaining species populations. Global change is rapidly altering environmental conditions, but, with the exception of coral-microalgae interactions, we know little of how this will affect symbiotic relationships. We here test how the effects of ocean acidification, from rising anthropogenic CO2 emissions, may alter symbiotic interactions between juvenile fish and their jellyfish hosts. Fishes treated with elevated seawater CO2 concentrations, as forecast for the end of the century on a business-as-usual greenhouse gas emission scenario, were negatively affected in their behaviour. The total time that fish (yellowtail scad) spent close to their jellyfish host in a choice arena where they could see and smell their host was approximately three times shorter under future compared with ambient CO2 conditions. Likewise, the mean number of attempts to associate with jellyfish was almost three times lower in CO2-treated compared with control fish, while only 63% (high CO2) versus 86% (control) of all individuals tested initiated an association at all. By contrast, none of three fish species tested were attracted solely to jellyfish olfactory cues under present-day CO2 conditions, suggesting that the altered fish-jellyfish association is not driven by negative effects of ocean acidification on olfaction. Because shelter is not widely available in the open water column and larvae of many (and often commercially important) pelagic species associate with jellyfish for protection against predators, modification of the fish-jellyfish symbiosis might lead to higher mortality and alter species population dynamics, and potentially have flow-on effects for their fisheries. PMID:27358374

  6. Ocean acidification alters fish-jellyfish symbiosis.

    PubMed

    Nagelkerken, Ivan; Pitt, Kylie A; Rutte, Melchior D; Geertsma, Robbert C

    2016-06-29

    Symbiotic relationships are common in nature, and are important for individual fitness and sustaining species populations. Global change is rapidly altering environmental conditions, but, with the exception of coral-microalgae interactions, we know little of how this will affect symbiotic relationships. We here test how the effects of ocean acidification, from rising anthropogenic CO2 emissions, may alter symbiotic interactions between juvenile fish and their jellyfish hosts. Fishes treated with elevated seawater CO2 concentrations, as forecast for the end of the century on a business-as-usual greenhouse gas emission scenario, were negatively affected in their behaviour. The total time that fish (yellowtail scad) spent close to their jellyfish host in a choice arena where they could see and smell their host was approximately three times shorter under future compared with ambient CO2 conditions. Likewise, the mean number of attempts to associate with jellyfish was almost three times lower in CO2-treated compared with control fish, while only 63% (high CO2) versus 86% (control) of all individuals tested initiated an association at all. By contrast, none of three fish species tested were attracted solely to jellyfish olfactory cues under present-day CO2 conditions, suggesting that the altered fish-jellyfish association is not driven by negative effects of ocean acidification on olfaction. Because shelter is not widely available in the open water column and larvae of many (and often commercially important) pelagic species associate with jellyfish for protection against predators, modification of the fish-jellyfish symbiosis might lead to higher mortality and alter species population dynamics, and potentially have flow-on effects for their fisheries.

  7. Degenerate In Vitro Genetic Selection Reveals Mutations That Diminish Alfalfa Mosaic Virus RNA Replication without Affecting Coat Protein Binding

    PubMed Central

    Rocheleau, Gail; Petrillo, Jessica; Guogas, Laura; Gehrke, Lee

    2004-01-01

    The alfalfa mosaic virus (AMV) RNAs are infectious only in the presence of the viral coat protein; however, the mechanisms describing coat protein's role during replication are disputed. We reasoned that mechanistic details might be revealed by identifying RNA mutations in the 3′-terminal coat protein binding domain that increased or decreased RNA replication without affecting coat protein binding. Degenerate (doped) in vitro genetic selection, based on a pool of randomized 39-mers, was used to select 30 variant RNAs that bound coat protein with high affinity. AUGC sequences that are conserved among AMV and ilarvirus RNAs were among the invariant nucleotides in the selected RNAs. Five representative clones were analyzed in functional assays, revealing diminished viral RNA expression resulting from apparent defects in replication and/or translation. These data identify a set of mutations, including G-U wobble pairs and nucleotide mismatches in the 5′ hairpin, which affect viral RNA functions without significant impact on coat protein binding. Because the mutations associated with diminished function were scattered over the 3′-terminal nucleotides, we considered the possibility that RNA conformational changes rather than disruption of a precise motif might limit activity. Native polyacrylamide gel electrophoresis experiments showed that the 3′ RNA conformation was indeed altered by nucleotide substitutions. One interpretation of the data is that coat protein binding to the AUGC sequences determines the orientation of the 3′ hairpins relative to one another, while local structural features within these hairpins are also critical determinants of functional activity. PMID:15254175

  8. Mutation affecting regulation of synthesis of acetohydroxy acid synthetase in Escherichia coli K-12.

    PubMed Central

    Jackson, J H; Henderson, E K

    1975-01-01

    Altered regulation of synthesis of acetohydroxy acid synthetase (AHAS) was previously reported in a mutant of Escherichia coli strain K-12. The mutant strain, growing in minimal medium, exhibits a partial growth limiatation and derepression of AHAS, owing to deficient synthesis of isoleucine. The genetic lesion (ilvE503) causing the isoleucine limitation was shown to cause derepression of a valine-sensitive AHAS activity. The derepression effect of the ilvE503 mutation upon synthesis of AHAS was conclusively demonstrated by introducing both the ilvE503 allele and an altered AHAS (ilv-521) into the same cell. Evidence is presented that suggests the presence of multiple genetic regions for synthesis and control of the valine-sensitive AHAS activity. PMID:1089632

  9. Single amino acid mutation in alpha-helical peptide affect second harmonic generation hyperpolarizability

    NASA Astrophysics Data System (ADS)

    Wei, Jing; Wang, Jin-Yun; Zhang, Min-Yi; Chai, Guo-Liang; Lin, Chen-Sheng; Cheng, Wen-Dan

    2013-01-01

    We investigate the effect of side chain on the first-order hyperpolarizability in α-helical polyalanine peptide with the 10th alanine mutation (Acetyl(ala)9X(ala)7NH2). Structures of various substituted peptides are optimized by ONIOM (DFT: AM1) scheme, and then linear and nonlinear optical properties are calculated by SOS//CIS/6-31G∗ method. The polarizability and first-order hyperpolarizability increase obviously only when 'X' represents phenylalanine, tyrosine and tryptophan. We also discuss the origin of nonlinear optical response and determine what caused the increase of first-order hyperpolarizability. Our results strongly suggest that side chains containing benzene, phenol and indole have important contributions to first-order hyperpolarizability.

  10. Sex-reversing mutations affect the architecture of SRY-DNA complexes.

    PubMed Central

    Pontiggia, A; Rimini, R; Harley, V R; Goodfellow, P N; Lovell-Badge, R; Bianchi, M E

    1994-01-01

    The testis determining factor, SRY, is a DNA binding protein that causes a large distortion of its DNA target sites. We have analysed the biochemical properties of the DNA binding domains (HMG-boxes) of mutant SRY proteins from five patients with complete gonadal dysgenesis. The mutant proteins fall into three categories: two bind and bend DNA almost normally, two bind inefficiently but bend DNA normally and one binds DNA with almost normal affinity but produces a different angle. The mutations with moderate effect on complex formation can be transmitted to male progeny, the ones with severe effects on either binding or bending are de novo. The angle induced by SRY depends on the exact DNA sequence and thus adds another level of discrimination in target site recognition. These data suggest that the exact spatial arrangement of the nucleoprotein complex organized by SRY is essential for sex determination. Images PMID:7813448

  11. Mutations in the bvgA gene of Bordetella pertussis that differentially affect regulation of virulence determinants.

    PubMed Central

    Stibitz, S

    1994-01-01

    By using chemical mutagenesis and genetic mapping, a search was undertaken for previously undescribed genes which may be involved in different regulatory mechanisms governing different virulence factors of Bordetella pertussis. Previous studies have shown that the fha locus encoding filamentous hemagglutinin is regulated directly by the bvgAS two component system, while regulation of ptx encoding pertussis toxin is less direct or occurs by a different mechanism. With a strain containing gene fusions to each of these regulated loci, screening was done for mutations which were defective for ptx expression but maintained normal or nearly normal levels of fha expression. Two mutations which had such a phenotype and were also deficient in adenylate cyclase toxin/hemolysin expression were found and characterized more fully. Both were found to affect residues in the C-terminal portion of the BvgA response regulator protein, a domain which shares sequence similarity with a family of regulatory proteins including FixJ, UhpA, MalT, RcsA, RcsB, and LuxR. The residues affected are within a region which, by extension from studies on the LuxR protein, may be involved in transcriptional activation. Images PMID:8083156

  12. Mutations of Arabidopsis TBL32 and TBL33 affect xylan acetylation and secondary wall deposition

    DOE PAGES

    Yuan, Youxi; Teng, Quincy; Zhong, Ruiqin; Haghighat, Marziyeh; Richardson, Elizabeth A.; Ye, Zheng -Hua; Zhang, Jin -Song

    2016-01-08

    Xylan is a major acetylated polymer in plant lignocellulosic biomass and it can be monoand di-acetylated at O-2 and O-3 as well as mono-acetylated at O-3 of xylosyl residues that is substituted with glucuronic acid (GlcA) at O-2. Based on the finding that ESK1, an Arabidopsis thaliana DUF231 protein, specifically mediates xylan 2-O- and 3-O-monoacetylation, we previously proposed that different acetyltransferase activities are required for regiospecific acetyl substitutions of xylan. Here, we demonstrate the functional roles of TBL32 and TBL33, two ESK1 close homologs, in acetyl substitutions of xylan. Simultaneous mutations of TBL32 and TBL33 resulted in a significant reductionmore » in xylan acetyl content and endoxylanase digestion of the mutant xylan released GlcA-substituted xylooligomers without acetyl groups. Structural analysis of xylan revealed that the tbl32 tbl33 mutant had a nearly complete loss of 3-O-acetylated, 2-O-GlcA-substituted xylosyl residues. A reduction in 3-Omonoacetylated and 2,3-di-O-acetylated xylosyl residues was also observed. Simultaneous mutations of TBL32, TBL33 and ESK1 resulted in a severe reduction in xylan acetyl level down to 15% of that of the wild type, and concomitantly, severely collapsed vessels and stunted plant growth. In particular, the S2 layer of secondary walls in xylem vessels of tbl33 esk1 and tbl32 tbl33 esk1 exhibited an altered structure, indicating abnormal assembly of secondary wall polymers. Furthermore, these results demonstrate that TBL32 and TBL33 play an important role in xylan acetylation and normal deposition of secondary walls.« less

  13. Mutations of Arabidopsis TBL32 and TBL33 Affect Xylan Acetylation and Secondary Wall Deposition

    PubMed Central

    Yuan, Youxi; Teng, Quincy; Zhong, Ruiqin; Haghighat, Marziyeh; Richardson, Elizabeth A.; Ye, Zheng-Hua

    2016-01-01

    Xylan is a major acetylated polymer in plant lignocellulosic biomass and it can be mono- and di-acetylated at O-2 and O-3 as well as mono-acetylated at O-3 of xylosyl residues that is substituted with glucuronic acid (GlcA) at O-2. Based on the finding that ESK1, an Arabidopsis thaliana DUF231 protein, specifically mediates xylan 2-O- and 3-O-monoacetylation, we previously proposed that different acetyltransferase activities are required for regiospecific acetyl substitutions of xylan. Here, we demonstrate the functional roles of TBL32 and TBL33, two ESK1 close homologs, in acetyl substitutions of xylan. Simultaneous mutations of TBL32 and TBL33 resulted in a significant reduction in xylan acetyl content and endoxylanase digestion of the mutant xylan released GlcA-substituted xylooligomers without acetyl groups. Structural analysis of xylan revealed that the tbl32 tbl33 mutant had a nearly complete loss of 3-O-acetylated, 2-O-GlcA-substituted xylosyl residues. A reduction in 3-O-monoacetylated and 2,3-di-O-acetylated xylosyl residues was also observed. Simultaneous mutations of TBL32, TBL33 and ESK1 resulted in a severe reduction in xylan acetyl level down to 15% of that of the wild type, and concomitantly, severely collapsed vessels and stunted plant growth. In particular, the S2 layer of secondary walls in xylem vessels of tbl33 esk1 and tbl32 tbl33 esk1 exhibited an altered structure, indicating abnormal assembly of secondary wall polymers. These results demonstrate that TBL32 and TBL33 play an important role in xylan acetylation and normal deposition of secondary walls. PMID:26745802

  14. The functional consequences of mis-sense mutations affecting an intra-molecular salt bridge in arylsulphatase A.

    PubMed Central

    Schestag, Frank; Yaghootfam, Afshin; Habetha, Matthias; Poeppel, Peter; Dietz, Frank; Klein, Roger A; Zlotogora, Joel; Gieselmann, Volkmar

    2002-01-01

    Metachromatic leukodystrophy is a lysosomal storage disorder caused by the deficiency of arylsulphatase A. We describe the functional consequences of three mis-sense mutations in the arylsulphatase A gene (Asp-335-Val, Arg-370-Trp and Arg-370-Gln), affecting an apparent intramolecular Asp-335 to Arg-370 salt bridge, and interpret the effects and clinical consequences on the basis of the three-dimensional structure of arylsulphatase A. Asp-335-Val and Arg-370-Trp substitutions each cause a complete loss of enzyme activity and are associated with the most severe form of the human disease, whereas the Arg-370-Gln-substituted enzyme retains some residual activity, being found in a patient suffering from the milder juvenile form of the disease. Detailed analysis reveals that formation of the apparent salt bridge depends critically on the presence of aspartic acid and arginine residues at positions 335 and 370, respectively. Substitution by various other amino acids, including glutamic acid and lysine, affects enzyme function severely. Biosynthesis and immunoprecipitation studies indicate that the Asp-335-Val substitution affects folding of arylsulphatase A more severely than either the Arg-370-Trp or Arg-370-Gln substitutions. In vitro mutagenesis data show that clinical severity correlates with the space occupied by residue 370. The combination with structural data suggests that the bulky tryptophan residue broadens the cleft held together by the apparent salt bridge, whereas the smaller glutamine residue still allows the cleft to close, yielding a less severely affected enzyme. The position of residue 370 in the three-dimensional structure of the enzyme provides a plausible explanation for the differing severities in loss of enzyme function caused by the mutations and thus the clinical phenotype. PMID:12086582

  15. Effects of nano-ZnO on the agronomically relevant Rhizobium-legume symbiosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of nano-ZnO (nZnO) on Rhizobium-legume symbiosis was studied with garden pea and its compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure of peas to nZnO had no impact on germination, but significantly affected root length. Chronic exposure of plant to nZnO impac...

  16. Effects of nano-TiO2 on the agronomically-relevant Rhizobium-legume symbiosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of nano-TiO2 on Rhizobium-legume symbiosis was studied using garden peas and the compatible bacterial partner Rhizobium leguminosarum bv. viciae 3841. Exposure to nano-TiO2 did not affect the germination of peas grown aseptically, nor did it impact the gross root structure. However, nano-...

  17. Point mutation of H3/H4 histones affects acetic acid tolerance in Saccharomyces cerevisiae.

    PubMed

    Liu, Xiangyong; Zhang, Xiaohua; Zhang, Zhaojie

    2014-10-10

    The molecular mechanism of acetic acid tolerance in yeast remains unclear despite of its importance for efficient cellulosic ethanol production. In this study, we examined the effects of histone H3/H4 point mutations on yeast acetic acid tolerance by comprehensively screening a histone H3/H4 mutant library. A total of 24 histone H3/H4 mutants (six acetic acid resistant and 18 sensitive) were identified. Compared to the wild-type strain, the histone acetic acid-resistant mutants exhibited improved ethanol fermentation performance under acetic acid stress. Genome-wide transcriptome analysis revealed that changes in the gene expression in the acetic acid-resistant mutants H3 K37A and H4 K16Q were mainly related to energy production, antioxidative stress. Our results provide novel insights into yeast acetic acid tolerance on the basis of histone, and suggest a novel approach to improve ethanol production by altering the histone H3/H4 sequences.

  18. Characterization and genetic mapping of a mutation affecting apurinic endonuclease activity in Staphylococcus aureus.

    PubMed Central

    Tam, J E; Pattee, P A

    1986-01-01

    Protoplast fusion between the Rec- mutant RN981 (L. Wyman, R. V. Goering, and R. P. Novick, Genetics 76:681-702, 1974) of Staphylococcus aureus NCTC 8325 and a Rec+ NCTC 8325 derivative yielded Rec+ recombinants that exhibited the increased sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine characteristic of RN981. Transformation analyses identified a specific mutation, designated ngr-374, that was responsible not only for N-methyl-N'-nitro-N-nitrosoguanidine sensitivity, but also sensitivity to methyl methanesulfonate, ethyl methanesulfonate, nitrous acid, and UV irradiation. However, ngr-374-carrying recombinants showed no significant increase in their sensitivity to mitomycin C or 4-nitroquinoline 1-oxide and were unaffected in recombination proficiency. In vitro assays showed that ngr-374-carrying strains had lower apurinic/apyrimidinic endonuclease activities than the wild type. The chromosomal locus occupied by ngr-374 was shown to exist in the gene order omega(Chr::Tn551)40-ngr-374-thrB106. PMID:2430940

  19. Lethal Factor Active-Site Mutations Affect Catalytic Activity In Vitro

    PubMed Central

    Hammond, S. E.; Hanna, P. C.

    1998-01-01

    The lethal factor (LF) protein of Bacillus anthracis lethal toxin contains the thermolysin-like active-site and zinc-binding consensus motif HEXXH (K. R. Klimpel, N. Arora, and S. H. Leppla, Mol. Microbiol. 13:1093–1100, 1994). LF is hypothesized to act as a Zn2+ metalloprotease in the cytoplasm of macrophages, but no proteolytic activities have been previously shown on any target substrate. Here, synthetic peptides are hydrolyzed by LF in vitro. Mass spectroscopy and peptide sequencing of isolated cleavage products separated by reverse-phase high-pressure liquid chromatography indicate that LF seems to prefer proline-containing substrates. Substitution mutations within the consensus active-site residues completely abolish all in vitro catalytic functions, as does addition of 1,10-phenanthroline, EDTA, and certain amino acid hydroxamates, including the novel zinc metalloprotease inhibitor ZINCOV. In contrast, the protease inhibitors bestatin and lysine CMK, previously shown to block LF activity on macrophages, did not block LF activity in vitro. These data provide the first direct evidence that LF may act as an endopeptidase. PMID:9573135

  20. Mutation in the C-Di-AMP Cyclase dacA Affects Fitness and Resistance of Methicillin Resistant Staphylococcus aureus

    PubMed Central

    Dengler, Vanina; McCallum, Nadine; Kiefer, Patrick; Christen, Philipp; Patrignani, Andrea; Vorholt, Julia A.; Berger-Bächi, Brigitte; Senn, Maria M.

    2013-01-01

    Faster growing and more virulent strains of methicillin resistant Staphylococcus aureus (MRSA) are increasingly displacing highly resistant MRSA. Elevated fitness in these MRSA is often accompanied by decreased and heterogeneous levels of methicillin resistance; however, the mechanisms for this phenomenon are not yet fully understood. Whole genome sequencing was used to investigate the genetic basis of this apparent correlation, in an isogenic MRSA strain pair that differed in methicillin resistance levels and fitness, with respect to growth rate. Sequencing revealed only one single nucleotide polymorphism (SNP) in the diadenylate cyclase gene dacA in the faster growing but less resistant strain. Diadenylate cyclases were recently discovered to synthesize the new second messenger cyclic diadenosine monophosphate (c-di-AMP). Introduction of this mutation into the highly resistant but slower growing strain reduced resistance and increased its growth rate, suggesting a direct connection between the dacA mutation and the phenotypic differences of these strains. Quantification of cellular c-di-AMP revealed that the dacA mutation decreased c-di-AMP levels resulting in reduced autolysis, increased salt tolerance and a reduction in the basal expression of the cell wall stress stimulon. These results indicate that c-di-AMP affects cell envelope-related signalling in S. aureus. The influence of c-di-AMP on growth rate and methicillin resistance in MRSA indicate that altering c-di-AMP levels could be a mechanism by which MRSA strains can increase their fitness levels by reducing their methicillin resistance levels. PMID:24013956

  1. Mutations which affect the inhibition of protein phosphatase 2A by simian virus 40 small-t antigen in vitro decrease viral transformation.

    PubMed Central

    Mungre, S; Enderle, K; Turk, B; Porrás, A; Wu, Y Q; Mumby, M C; Rundell, K

    1994-01-01

    Three independent point mutations within residues 97 to 103 of the simian virus 40-small-t antigen (small-t) greatly reduced the ability of purified small-t to inhibit protein phosphatase 2A in vitro. These mutations affected the interaction of small-t antigen with the protein phosphatase 2A A subunit translated in vitro, and a peptide from the region identified by these mutations released the A subunit from immune complexes. When introduced into virus, the mutations eliminated the ability of small-t to enhance viral transformation of growth-arrested rat F111 cells. In contrast, the mutant small-t antigens were unimpaired in the transactivation of the adenovirus E2 promoter, an activity which was reduced by a double mutation in small-t residues 43 and 45. Images PMID:8107228

  2. Hypertrophic cardiomyopathy mutations in the calponin-homology domain of ACTN2 affect actin binding and cardiomyocyte Z-disc incorporation

    PubMed Central

    Haywood, Natalie J.; Wolny, Marcin; Rogers, Brendan; Trinh, Chi H.; Shuping, Yu; Edwards, Thomas A.; Peckham, Michelle

    2016-01-01

    α-Actinin-2 (ACTN2) is the only muscle isoform of α-actinin expressed in cardiac muscle. Mutations in this protein have been implicated in mild to moderate forms of hypertrophic cardiomyopathy (HCM). We have investigated the effects of two mutations identified from HCM patients, A119T and G111V, on the secondary and tertiary structure of a purified actin binding domain (ABD) of ACTN2 by circular dichroism and X-ray crystallography, and show small but distinct changes for both mutations. We also find that both mutants have reduced F-actin binding affinity, although the differences are not significant. The full length mEos2 tagged protein expressed in adult cardiomyocytes shows that both mutations additionally affect Z-disc localization and dynamic behaviour. Overall, these two mutations have small effects on structure, function and behaviour, which may contribute to a mild phenotype for this disease. PMID:27287556

  3. Epididymal protein synthesis and secretion in strains of mice bearing single gene mutations which affect fertility.

    PubMed

    Holland, M K; Orgebin-Crist, M C

    1988-03-01

    Mice bearing gene mutations that, among other effects, render the males infertile were examined. Serum testosterone was within the normal range (0.8-1.8 ng/ml), and sperm numbers in the testis and epididymis were not different between mutant animals and coisogenic wild types. All mutants, except mocha and achondroplasia, displayed normal mating behavior. However, in all genotypes, fewer fertilized eggs were recovered from females mated by mutants. In vitro fertilization tests showed that all mutants--except bouncy--fertilized similar numbers of eggs to wild types. Spermatozoa from bouncy mutants also bound to eggs in lower numbers. These findings indicate that spermatozoa from the bouncy mutant have a severe defect in sperm-zona interaction. When bouncy spermatozoa were tested for sperm-vitelline membrane interaction at a low (10:1) sperm to egg ratio, they penetrated fewer zona-free hamster eggs. Epididymal protein synthesis and secretion were comparable between wild-type animals from all genotypes. However, while the regional pattern of protein synthesis was comparable among all mutants, the absolute rate of protein synthesis (cpm per mg tissue) was lower in some cases. Nevertheless, the proportion of the proteins synthesized that appeared in the medium remained constant. When the regional profile of proteins secreted by mutants was compared to that of their coisogenic wild types, three types of differences were noted: (1) changes in the abundance of a protein, (2) changes in the region of the epididymis from which a protein was secreted, or (3) the absence of a protein.

  4. Heavy metal stress in alders: Tolerance and vulnerability of the actinorhizal symbiosis.

    PubMed

    Bélanger, Pier-Anne; Bellenger, Jean-Philippe; Roy, Sébastien

    2015-11-01

    Alders have already demonstrated their potential for the revegetation of both mining and industrial sites. These actinorhizal trees and shrubs and the actinobacteria Frankia associate in a nitrogen-fixing symbiosis which could however be negatively affected by the presence of heavy metals, and accumulate them. In our hydroponic assay with black alders, quantification of the roots and shoots metal concentrations showed that, in the absence of stress, symbiosis increases Mo and Ni root content and simultaneously decreases Mo shoot content. Interestingly, the Mo shoot content also decreases in the presence of Ni, Cu, Pb, Zn and Cd for symbiotic alders. In symbiotic alders, Pb shoot translocation was promoted in presence of Pb. On the other hand, Cd exclusion in symbiotic root tissues was observed with Pb and Cd. In the presence of symbiosis, only Cd and Pb showed translocation into aerial tissues when present in the nutrient solution. Moreover, the translocation of Ni to shoot was prevented by symbiosis in the presence of Cd, Ni and Pb. The hydroponic experiment demonstrated that alders benefit from the symbiosis, producing more biomass (total, root and shoot) than non nodulated alders in control condition, and in the presence of metals (Cu, Ni, Zn, Pb and Cd). Heavy metals did not reduce the nodule numbers (SNN), but the presence of Zn or Cd did reduce nodule allocation. Our study suggests that the Frankia-alder symbiosis is a promising (and a compatible) plant-microorganism association for the revegetation of contaminated sites, with minimal risk of metal dispersion. PMID:26091871

  5. Systematic screening for mutations in the human serotonin 1F receptor gene in patients with bipolar affective disorder and schizophrenia

    SciTech Connect

    Shimron-Abarbanell, D.; Harms, H.; Erdmann, J.; Propping, P.; Noethen, M.M.

    1996-04-09

    Using single strand conformational analysis we screened the complete coding sequence of the serotonin 1F (5-HT{sub 1F}) receptor gene for the presence of DNA sequence variation in a sample of 137 unrelated individuals including 45 schizophrenic patients, 46 bipolar patients, as well as 46 healthy controls. We detected only three rare sequence variants which are characterized by single base pair substitutions, namely a silent T{r_arrow}A transversion in the third position of codon 261 (encoding isoleucine), a silent C{r_arrow}T transition in the third position of codon 176 (encoding histidine), and a C{r_arrow}T transition in position -78 upstream from the start codon. The lack of significant mutations in patients suffering from schizophrenia and bipolar affective disorder indicates that the 5-HT{sub 1F} receptor is not commonly involved in the etiology of these diseases. 12 refs., 1 fig., 2 tabs.

  6. Mutations that affect structure and assembly of light-harvesting proteins in the cyanobacterium Synechocystis sp. strain 6701

    SciTech Connect

    Anderson, L.K.; Rayner, M.C.; Eiserling, F.A.

    1987-01-01

    The unicellular cyanobacterium Synechocystis sp. strain 6701 was mutagenized with UV irradiation and screened for pigment changes that indicated genetic lesions involving the light-harvesting proteins of the phycobilisome. A previous examination of the pigment mutant UV16 showed an assembly defect in the phycocyanin component of the phycobilisome. Mutagenesis of UV16 produced an additional double mutant, UV16-40, with decreased phycoerythrin content. Phycocyanin and phycoerythrin were isolated from UV16-40 and compared with normal biliproteins. The results suggested that the UV16 mutation affected the alpha subunit of phycocyanin, while the phycoerythrin beta subunit from UV16-40 had lost one of its three chromophores. Characterization of the unassembled phycobilisome components in these mutants suggests that these strains will be useful for probing in vivo the regulated expression and assembly of phycobilisomes.

  7. Interleukin-6 Deficiency Does Not Affect Motor Neuron Disease Caused by Superoxide Dismutase 1 Mutation

    PubMed Central

    Han, Yongmei; Ripley, Barry; Serada, Satoshi; Naka, Tetsuji; Fujimoto, Minoru

    2016-01-01

    Background & Aim Amyotrophic Lateral Sclerosis (ALS) is an adult-onset, progressive, motor neuron degenerative disease. Recent evidence indicates that inflammation is associated with many neurodegenerative diseases including ALS. Previously, abnormal levels of inflammatory cytokines including IL-1β, IL-6 and TNF-α were described in ALS patients and/or in mouse ALS models. In addition, one study showed that blocking IL-1β could slow down progression of ALS-like symptoms in mice. In this study, we examined a role for IL-6 in ALS, using an animal model for familial ALS. Methods Mice with mutant SOD1 (G93A) transgene, a model for familial ALS, were used in this study. The expression of the major inflammatory cytokines, IL-6, IL-1β and TNF-α, in spinal cords of these SOD1 transgenic (TG) mice were assessed by real time PCR. Mice were then crossed with IL-6(-/-) mice to generate SOD1TG/IL-6(-/-) mice. SOD1 TG/IL-6(-/-) mice (n = 17) were compared with SOD1 TG/IL-6(+/-) mice (n = 18), SOD1 TG/IL-6(+/+) mice (n = 11), WT mice (n = 15), IL-6(+/-) mice (n = 5) and IL-6(-/-) mice (n = 8), with respect to neurological disease severity score, body weight and the survival. We also histologically compared the motor neuron loss in lumber spinal cords and the atrophy of hamstring muscles between these mouse groups. Results Levels of IL-6, IL-1β and TNF-α in spinal cords of SOD1 TG mice was increased compared to WT mice. However, SOD1 TG/IL-6(-/-) mice exhibited weight loss, deterioration in motor function and shortened lifespan (167.55 ± 11.52 days), similarly to SOD1 TG /IL-6(+/+) mice (164.31±12.16 days). Motor neuron numbers and IL-1β and TNF-α levels in spinal cords were not significantly different in SOD1 TG /IL-6(-/-) mice and SOD1 TG /IL-6 (+/+) mice. Conclusion These results provide compelling preclinical evidence indicating that IL-6 does not directly contribute to motor neuron disease caused by SOD1 mutations. PMID:27070121

  8. Engineering of formate dehydrogenase: synergistic effect of mutations affecting cofactor specificity and chemical stability.

    PubMed

    Hoelsch, Kathrin; Sührer, Ilka; Heusel, Moritz; Weuster-Botz, Dirk

    2013-03-01

    Formate dehydrogenases (FDHs) are frequently used for the regeneration of cofactors in biotransformations employing NAD(P)H-dependent oxidoreductases. Major drawbacks of most native FDHs are their strong preference for NAD(+) and their low operational stability in the presence of reactive organic compounds such as α-haloketones. In this study, the FDH from Mycobacterium vaccae N10 (MycFDH) was engineered in order to obtain an enzyme that is not only capable of regenerating NADPH but also stable toward the α-haloketone ethyl 4-chloroacetoacetate (ECAA). To change the cofactor specificity, amino acids in the conserved NAD(+) binding motif were mutated. Among these mutants, MycFDH A198G/D221Q had the highest catalytic efficiency (k cat/K m) with NADP(+). The additional replacement of two cysteines (C145S/C255V) not only conferred a high resistance to ECAA but also enhanced the catalytic efficiency 6-fold. The resulting quadruple mutant MycFDH C145S/A198G/D221Q/C255V had a specific activity of 4.00 ± 0.13 U mg(-1) and a K m, NADP(+) of 0.147 ± 0.020 mM at 30 °C, pH 7. The A198G replacement had a major impact on the kinetic constants of the enzyme. The corresponding triple mutant, MycFDH C145S/D221Q/C255V, showed the highest specific activity reported to date for a NADP(+)-accepting FDH (v max, 10.25 ± 1.63 U mg(-1)). However, the half-saturation constant for NADP(+) (K m, NADP(+) , 0.92 ± 0.10 mM) was about one order of magnitude higher than the one of the quadruple mutant. Depending on the reaction setup, both novel MycFDH variants could be useful for the production of the chiral synthon ethyl (S)-4-chloro-3-hydroxybutyrate [(S)-ECHB] by asymmetric reduction of ECAA with NADPH-dependent ketoreductases.

  9. STN1 OB Fold Mutation Alters DNA Binding and Affects Selective Aspects of CST Function

    PubMed Central

    Bhattacharjee, Anukana; Stewart, Jason; Chaiken, Mary; Price, Carolyn M.

    2016-01-01

    Mammalian CST (CTC1-STN1-TEN1) participates in multiple aspects of telomere replication and genome-wide recovery from replication stress. CST resembles Replication Protein A (RPA) in that it binds ssDNA and STN1 and TEN1 are structurally similar to RPA2 and RPA3. Conservation between CTC1 and RPA1 is less apparent. Currently the mechanism underlying CST action is largely unknown. Here we address CST mechanism by using a DNA-binding mutant, (STN1 OB-fold mutant, STN1-OBM) to examine the relationship between DNA binding and CST function. In vivo, STN1-OBM affects resolution of endogenous replication stress and telomere duplex replication but telomeric C-strand fill-in and new origin firing after exogenous replication stress are unaffected. These selective effects indicate mechanistic differences in CST action during resolution of different replication problems. In vitro binding studies show that STN1 directly engages both short and long ssDNA oligonucleotides, however STN1-OBM preferentially destabilizes binding to short substrates. The finding that STN1-OBM affects binding to only certain substrates starts to explain the in vivo separation of function observed in STN1-OBM expressing cells. CST is expected to engage DNA substrates of varied length and structure as it acts to resolve different replication problems. Since STN1-OBM will alter CST binding to only some of these substrates, the mutant should affect resolution of only a subset of replication problems, as was observed in the STN1-OBM cells. The in vitro studies also provide insight into CST binding mechanism. Like RPA, CST likely contacts DNA via multiple OB folds. However, the importance of STN1 for binding short substrates indicates differences in the architecture of CST and RPA DNA-protein complexes. Based on our results, we propose a dynamic DNA binding model that provides a general mechanism for CST action at diverse forms of replication stress. PMID:27690379

  10. Interacting genes that affect microtubule function in Drosophila melanogaster: Two classes of mutation revert the failure to complement between hay sup nc2 and mutations in tubulin genes

    SciTech Connect

    Regan, C.L.; Fuller, M.T. )

    1990-05-01

    The recessive male sterile mutation hay{sup nc2} of Drosophila melanogaster fails to complement certain {beta}{sub 2}-tubulin and {alpha}-tubulin mutations, suggesting that the haywire product plays a role in microtubule function, perhaps as a structural component of microtubules. The genetic interaction appears to require the presence of the aberrant product encoded by hay{sup nc2}, which may act as a structural poison. Based on this observation, the authors have isolated ten new mutations with EMS that revert the failure to complement between hay{sup nc2} and B2t{sup n}. The revertants tested behaved as intragenic mutations of hay in recombination tests, and feel into two phenotypic classes, suggesting two functional domains of the hay gene product. Some revertants were hemizygous viable and less severe than hay{sup nc2} in their recessive phenotype. These mutations might revert the poison by restoring the aberrant product encoded by the hay{sup nc2} allele to more wild-type function. Most of the revertants were recessive lethal mutations, indicating that the hay gene product is essential for viability. These more extreme mutations could revert the poison by destroying the ability of the aberrant haywire{sup nc2} product to interact structurally with microtubules. Flies heterozygous for the original hay{sup nc2} allele and an extreme revertant show defects in both the structure and the function of the male meiotic spindle.

  11. Molecular analysis of HEXA gene in Argentinean patients affected with Tay-Sachs disease: possible common origin of the prevalent c.459+5A>G mutation.

    PubMed

    Zampieri, Stefania; Montalvo, Annalisa; Blanco, Mariana; Zanin, Irene; Amartino, Hernan; Vlahovicek, Kristian; Szlago, Marina; Schenone, Andrea; Pittis, Gabriela; Bembi, Bruno; Dardis, Andrea

    2012-05-15

    Tay-Sachs disease (TSD) is a recessively inherited disorder caused by the deficient activity of hexosaminidase A due to mutations in the HEXA gene. Up to date there is no information regarding the molecular genetics of TSD in Argentinean patients. In the present study we have studied 17 Argentinean families affected by TSD, including 20 patients with the acute infantile form and 3 with the sub-acute form. Overall, we identified 14 different mutations accounting for 100% of the studied alleles. Eight mutations were novel: 5 were single base changes leading to drastic residue changes or truncated proteins, 2 were small deletions and one was an intronic mutation that may cause a splicing defect. Although the spectrum of mutations was highly heterogeneous, a high frequency of the c.459+5G>A mutation, previously described in different populations was found among the studied cohort. Haplotype analysis suggested that in these families the c.459+5G>A mutation might have arisen by a single mutational event.

  12. Molecular analysis of HEXA gene in Argentinean patients affected with Tay-Sachs disease: possible common origin of the prevalent c.459+5A>G mutation.

    PubMed

    Zampieri, Stefania; Montalvo, Annalisa; Blanco, Mariana; Zanin, Irene; Amartino, Hernan; Vlahovicek, Kristian; Szlago, Marina; Schenone, Andrea; Pittis, Gabriela; Bembi, Bruno; Dardis, Andrea

    2012-05-15

    Tay-Sachs disease (TSD) is a recessively inherited disorder caused by the deficient activity of hexosaminidase A due to mutations in the HEXA gene. Up to date there is no information regarding the molecular genetics of TSD in Argentinean patients. In the present study we have studied 17 Argentinean families affected by TSD, including 20 patients with the acute infantile form and 3 with the sub-acute form. Overall, we identified 14 different mutations accounting for 100% of the studied alleles. Eight mutations were novel: 5 were single base changes leading to drastic residue changes or truncated proteins, 2 were small deletions and one was an intronic mutation that may cause a splicing defect. Although the spectrum of mutations was highly heterogeneous, a high frequency of the c.459+5G>A mutation, previously described in different populations was found among the studied cohort. Haplotype analysis suggested that in these families the c.459+5G>A mutation might have arisen by a single mutational event. PMID:22441121

  13. Unethical and Deadly Symbiosis in Higher Education

    ERIC Educational Resources Information Center

    Crumbley, D. Larry; Flinn, Ronald; Reichelt, Kenneth J.

    2012-01-01

    As administrators are pressured to increase retention rates in accounting departments, and higher education in general, a deadly symbiosis is occurring. Most students and parents only wish for high grades, so year after year many educators engage in unethical grade inflation and course work deflation. Since administrators use the students to audit…

  14. An affective disorder in zebrafish with mutation of the glucocorticoid receptor

    PubMed Central

    Ziv, Limor; Muto, Akira; Schoonheim, Peter J.; Meijsing, Sebastiaan H.; Strasser, Daniel; Ingraham, Holly A.; Schaaf, Marcel J.M.; Yamamoto, Keith R.; Baier, Herwig

    2012-01-01

    Upon binding of cortisol, the glucocorticoid receptor (GR) regulates the transcription of specific target genes, including those that encode the stress hormones corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH). Dysregulation of the stress axis is a hallmark of major depression in human patients. However, it is still unclear how glucocorticoid signaling is linked to affective disorders. We identified an adult-viable zebrafish mutant in which the negative feedback on the stress response is disrupted, due to abolition of all transcriptional activity of GR. As a consequence, cortisol is elevated, but unable to signal through GR. When placed into an unfamiliar aquarium (‘novel tank’), mutant fish become immobile (‘freeze’), show reduced exploratory behavior and do not habituate to this stressor upon repeated exposure. Addition of the antidepressant fluoxetine to the holding water and social interactions restore normal behavior, followed by a delayed correction of cortisol levels. Fluoxetine does not affect overall transcription of CRH, the mineralocorticoid receptor (MR), the serotonin transporter Serta or GR itself. Fluoxetine, however, suppresses the stress-induced upregulation of MR and Serta in both wildtype fish and mutants. Our studies show a conserved, protective function of glucocorticoid signaling in the regulation of emotional behavior and reveal novel molecular aspects of how chronic stress impacts vertebrate brain physiology and behavior. Importantly, the zebrafish model opens up the possibility of high-throughput drug screens in search of new classes of antidepressants. PMID:22641177

  15. An affective disorder in zebrafish with mutation of the glucocorticoid receptor.

    PubMed

    Ziv, L; Muto, A; Schoonheim, P J; Meijsing, S H; Strasser, D; Ingraham, H A; Schaaf, M J M; Yamamoto, K R; Baier, H

    2013-06-01

    Upon binding of cortisol, the glucocorticoid receptor (GR) regulates the transcription of specific target genes, including those that encode the stress hormones corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone. Dysregulation of the stress axis is a hallmark of major depression in human patients. However, it is still unclear how glucocorticoid signaling is linked to affective disorders. We identified an adult-viable zebrafish mutant in which the negative feedback on the stress response is disrupted, due to abolition of all transcriptional activity of GR. As a consequence, cortisol is elevated, but unable to signal through GR. When placed into an unfamiliar aquarium ('novel tank'), mutant fish become immobile ('freeze'), show reduced exploratory behavior and do not habituate to this stressor upon repeated exposure. Addition of the antidepressant fluoxetine to the holding water and social interactions restore normal behavior, followed by a delayed correction of cortisol levels. Fluoxetine does not affect the overall transcription of CRH, the mineralocorticoid receptor (MR), the serotonin transporter (Serta) or GR itself. Fluoxetine, however, suppresses the stress-induced upregulation of MR and Serta in both wild-type fish and mutants. Our studies show a conserved, protective function of glucocorticoid signaling in the regulation of emotional behavior and reveal novel molecular aspects of how chronic stress impacts vertebrate brain physiology and behavior. Importantly, the zebrafish model opens up the possibility of high-throughput drug screens in search of new classes of antidepressants. PMID:22641177

  16. Arabidopsis AtADF1 is functionally affected by mutations on actin binding sites.

    PubMed

    Dong, Chun-Hai; Tang, Wei-Ping; Liu, Jia-Yao

    2013-03-01

    The plant actin depolymerizing factor (ADF) binds to both monomeric and filamentous actin, and is directly involved in the depolymerization of actin filaments. To better understand the actin binding sites of the Arabidopsis thaliana L. AtADF1, we generated mutants of AtADF1 and investigated their functions in vitro and in vivo. Analysis of mutants harboring amino acid substitutions revealed that charged residues (Arg98 and Lys100) located at the α-helix 3 and forming an actin binding site together with the N-terminus are essential for both G- and F-actin binding. The basic residues on the β-strand 5 (K82/A) and the α-helix 4 (R135/A, R137/A) form another actin binding site that is important for F-actin binding. Using transient expression of CFP-tagged AtADF1 mutant proteins in onion (Allium cepa) peel epidermal cells and transgenic Arabidopsis thaliana L. plants overexpressing these mutants, we analyzed how these mutant proteins regulate actin organization and affect seedling growth. Our results show that the ADF mutants with a lower affinity for actin filament binding can still be functional, unless the affinity for actin monomers is also affected. The G-actin binding activity of the ADF plays an essential role in actin binding, depolymerization of actin polymers, and therefore in the control of actin organization. PMID:23190411

  17. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato.

    PubMed

    Ruiz-Lozano, Juan Manuel; Aroca, Ricardo; Zamarreño, Ángel María; Molina, Sonia; Andreo-Jiménez, Beatriz; Porcel, Rosa; García-Mina, José María; Ruyter-Spira, Carolien; López-Ráez, Juan Antonio

    2016-02-01

    Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant-AM fungus interaction remains largely unknown. In the present work, the effects of drought on lettuce and tomato plant performance and hormone levels were investigated in non-AM and AM plants. Three different water regimes were applied, and their effects were analysed over time. AM plants showed an improved growth rate and efficiency of photosystem II than non-AM plants under drought from very early stages of plant colonization. The levels of the phytohormone abscisic acid, as well as the expression of the corresponding marker genes, were influenced by drought stress in non-AM and AM plants. The levels of strigolactones and the expression of corresponding marker genes were affected by both AM symbiosis and drought. The results suggest that AM symbiosis alleviates drought stress by altering the hormonal profiles and affecting plant physiology in the host plant. In addition, a correlation between AM root colonization, strigolactone levels and drought severity is shown, suggesting that under these unfavourable conditions, plants might increase strigolactone production in order to promote symbiosis establishment to cope with the stress. PMID:26305264

  18. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato.

    PubMed

    Ruiz-Lozano, Juan Manuel; Aroca, Ricardo; Zamarreño, Ángel María; Molina, Sonia; Andreo-Jiménez, Beatriz; Porcel, Rosa; García-Mina, José María; Ruyter-Spira, Carolien; López-Ráez, Juan Antonio

    2016-02-01

    Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant-AM fungus interaction remains largely unknown. In the present work, the effects of drought on lettuce and tomato plant performance and hormone levels were investigated in non-AM and AM plants. Three different water regimes were applied, and their effects were analysed over time. AM plants showed an improved growth rate and efficiency of photosystem II than non-AM plants under drought from very early stages of plant colonization. The levels of the phytohormone abscisic acid, as well as the expression of the corresponding marker genes, were influenced by drought stress in non-AM and AM plants. The levels of strigolactones and the expression of corresponding marker genes were affected by both AM symbiosis and drought. The results suggest that AM symbiosis alleviates drought stress by altering the hormonal profiles and affecting plant physiology in the host plant. In addition, a correlation between AM root colonization, strigolactone levels and drought severity is shown, suggesting that under these unfavourable conditions, plants might increase strigolactone production in order to promote symbiosis establishment to cope with the stress.

  19. High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype-Phenotype Correlation.

    PubMed

    Rojnueangnit, Kitiwan; Xie, Jing; Gomes, Alicia; Sharp, Angela; Callens, Tom; Chen, Yunjia; Liu, Ying; Cochran, Meagan; Abbott, Mary-Alice; Atkin, Joan; Babovic-Vuksanovic, Dusica; Barnett, Christopher P; Crenshaw, Melissa; Bartholomew, Dennis W; Basel, Lina; Bellus, Gary; Ben-Shachar, Shay; Bialer, Martin G; Bick, David; Blumberg, Bruce; Cortes, Fanny; David, Karen L; Destree, Anne; Duat-Rodriguez, Anna; Earl, Dawn; Escobar, Luis; Eswara, Marthanda; Ezquieta, Begona; Frayling, Ian M; Frydman, Moshe; Gardner, Kathy; Gripp, Karen W; Hernández-Chico, Concepcion; Heyrman, Kurt; Ibrahim, Jennifer; Janssens, Sandra; Keena, Beth A; Llano-Rivas, Isabel; Leppig, Kathy; McDonald, Marie; Misra, Vinod K; Mulbury, Jennifer; Narayanan, Vinodh; Orenstein, Naama; Galvin-Parton, Patricia; Pedro, Helio; Pivnick, Eniko K; Powell, Cynthia M; Randolph, Linda; Raskin, Salmo; Rosell, Jordi; Rubin, Karol; Seashore, Margretta; Schaaf, Christian P; Scheuerle, Angela; Schultz, Meredith; Schorry, Elizabeth; Schnur, Rhonda; Siqveland, Elizabeth; Tkachuk, Amanda; Tonsgard, James; Upadhyaya, Meena; Verma, Ishwar C; Wallace, Stephanie; Williams, Charles; Zackai, Elaine; Zonana, Jonathan; Lazaro, Conxi; Claes, Kathleen; Korf, Bruce; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine

    2015-11-01

    Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P < 0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients. PMID:26178382

  20. High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype–Phenotype Correlation

    PubMed Central

    Rojnueangnit, Kitiwan; Xie, Jing; Gomes, Alicia; Sharp, Angela; Callens, Tom; Chen, Yunjia; Liu, Ying; Cochran, Meagan; Abbott, Mary‐Alice; Atkin, Joan; Babovic‐Vuksanovic, Dusica; Barnett, Christopher P.; Crenshaw, Melissa; Bartholomew, Dennis W.; Basel, Lina; Bellus, Gary; Ben‐Shachar, Shay; Bialer, Martin G.; Bick, David; Blumberg, Bruce; Cortes, Fanny; David, Karen L.; Destree, Anne; Duat‐Rodriguez, Anna; Earl, Dawn; Escobar, Luis; Eswara, Marthanda; Ezquieta, Begona; Frayling, Ian M.; Frydman, Moshe; Gardner, Kathy; Gripp, Karen W.; Hernández‐Chico, Concepcion; Heyrman, Kurt; Ibrahim, Jennifer; Janssens, Sandra; Keena, Beth A; Llano‐Rivas, Isabel; Leppig, Kathy; McDonald, Marie; Misra, Vinod K.; Mulbury, Jennifer; Narayanan, Vinodh; Orenstein, Naama; Galvin‐Parton, Patricia; Pedro, Helio; Pivnick, Eniko K.; Powell, Cynthia M.; Randolph, Linda; Raskin, Salmo; Rosell, Jordi; Rubin, Karol; Seashore, Margretta; Schaaf, Christian P.; Scheuerle, Angela; Schultz, Meredith; Schorry, Elizabeth; Schnur, Rhonda; Siqveland, Elizabeth; Tkachuk, Amanda; Tonsgard, James; Upadhyaya, Meena; Verma, Ishwar C.; Wallace, Stephanie; Williams, Charles; Zackai, Elaine; Zonana, Jonathan; Lazaro, Conxi; Claes, Kathleen; Korf, Bruce; Martin, Yolanda; Legius, Eric

    2015-01-01

    ABSTRACT Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype–phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café‐au‐lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan‐like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P < 0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1‐patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi‐exon deletion, providing genetic evidence that p.Arg1809Cys is a loss‐of‐function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype–phenotype correlation will affect counseling and management of a significant number of patients. PMID:26178382

  1. High Incidence of Noonan Syndrome Features Including Short Stature and Pulmonic Stenosis in Patients carrying NF1 Missense Mutations Affecting p.Arg1809: Genotype-Phenotype Correlation.

    PubMed

    Rojnueangnit, Kitiwan; Xie, Jing; Gomes, Alicia; Sharp, Angela; Callens, Tom; Chen, Yunjia; Liu, Ying; Cochran, Meagan; Abbott, Mary-Alice; Atkin, Joan; Babovic-Vuksanovic, Dusica; Barnett, Christopher P; Crenshaw, Melissa; Bartholomew, Dennis W; Basel, Lina; Bellus, Gary; Ben-Shachar, Shay; Bialer, Martin G; Bick, David; Blumberg, Bruce; Cortes, Fanny; David, Karen L; Destree, Anne; Duat-Rodriguez, Anna; Earl, Dawn; Escobar, Luis; Eswara, Marthanda; Ezquieta, Begona; Frayling, Ian M; Frydman, Moshe; Gardner, Kathy; Gripp, Karen W; Hernández-Chico, Concepcion; Heyrman, Kurt; Ibrahim, Jennifer; Janssens, Sandra; Keena, Beth A; Llano-Rivas, Isabel; Leppig, Kathy; McDonald, Marie; Misra, Vinod K; Mulbury, Jennifer; Narayanan, Vinodh; Orenstein, Naama; Galvin-Parton, Patricia; Pedro, Helio; Pivnick, Eniko K; Powell, Cynthia M; Randolph, Linda; Raskin, Salmo; Rosell, Jordi; Rubin, Karol; Seashore, Margretta; Schaaf, Christian P; Scheuerle, Angela; Schultz, Meredith; Schorry, Elizabeth; Schnur, Rhonda; Siqveland, Elizabeth; Tkachuk, Amanda; Tonsgard, James; Upadhyaya, Meena; Verma, Ishwar C; Wallace, Stephanie; Williams, Charles; Zackai, Elaine; Zonana, Jonathan; Lazaro, Conxi; Claes, Kathleen; Korf, Bruce; Martin, Yolanda; Legius, Eric; Messiaen, Ludwine

    2015-11-01

    Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple café-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P < 0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients.

  2. Morphogenesis in Mucor mucedo: mutations affecting gamone response and organ differentiation.

    PubMed

    Wurtz, T; Jockusch, H

    1978-02-27

    Mutants of Mucor mucedo minus strain that are affected in their trisporic acid (TA) mediated zygophore formation have been isolated. We have found mutants with cold sensitive (cs), with temperature sensitive (ts) and without zygophore formation as well as mutants with unstable zygophores (Zst-). From the appearence of certain pleiotropic phenotypes we deduce a one-dimensional sequence of states of competence of the mycelium to form different organs. TA appears to be a growth substance for zygophores acting on one transient state of competence. The fact that all isolates with lowered response to TA also have a lowered response to the mating type specific TA-precursor P strongly suggests that P has to be converted into TA before inducing zygophore growth. Furthermore, one mutant with lowered sensitivity to TA exhibits an excess zygophore formation in the presence of high TA-concentrations, while high concentrations of P cause a depressed zygophore formation (Fig. 6). Our interpretation of this behaviour is that P acts as an antagonist to TA in the regulation of zygophore growth.

  3. Mutations affecting sensitivity of the cellular slime mold Dictyostelium discoideum to DNA-damaging agents.

    PubMed

    Bronner, C E; Welker, D L; Deering, R A

    1992-09-01

    We describe 22 new mutants of D. discoideum that are sensitive to DNA damage. These mutants were isolated on the basis of sensitivity to either temperature, gamma-rays, or 4-nitroquinolone-1-oxide (4NQO). The doses of gamma-rays, ultraviolet light (UV), and 4NQO required to reduce the survival of colony-forming ability of these mutants to 10% (D10) range from 2% to 100% of the D10s for the nonmutant, parent strains. For most of the mutants, those which are very sensitive to one agent are very sensitive to all agents tested and those which are moderately sensitive to one agent, are moderately sensitive to all agents tested. One mutant is sensitive only to 4NQO. Linkage relationships have been examined for 13 of these mutants. This linkage information was used to design complementation tests to determine allelism with previously characterized complementation groups affecting sensitivity to radiation. 4 of the new mutants fall within previously identified complementation groups and 3 new complementation groups have been identified (radJ, radK and radL). Other new loci probably also exist among these new mutants. This brings the number of characterized mutants of D. discoideum which are sensitive to DNA-damaging agents to 33 and the number of assigned complementation groups to 11. PMID:1380652

  4. Epigenetic Mutation of RAV6 Affects Leaf Angle and Seed Size in Rice.

    PubMed

    Zhang, Xiangqian; Sun, Jing; Cao, Xiaofeng; Song, Xianwei

    2015-11-01

    Heritable epigenetic variants of genes, termed epialleles, can broaden genetic and phenotypic diversity in eukaryotes. Epialleles may also provide a new source of beneficial traits for crop breeding, but very few epialleles related to agricultural traits have been identified in crops. Here, we identified Epi-rav6, a gain-of-function epiallele of rice (Oryza sativa) RELATED TO ABSCISIC ACID INSENSITIVE3 (ABI3)/VIVIPAROUS1 (VP1) 6 (RAV6), which encodes a B3 DNA-binding domain-containing protein. The Epi-rav6 plants show larger lamina inclination and smaller grain size; these agronomically important phenotypes are inherited in a semidominant manner. We did not find nucleotide sequence variation of RAV6. Instead, we found hypomethylation in the promoter region of RAV6, which caused ectopic expression of RAV6 in Epi-rav6 plants. Bisulfite analysis revealed that cytosine methylation of four CG and two CNG loci within a continuous 96-bp region plays essential roles in regulating RAV6 expression; this region contains a conserved miniature inverted repeat transposable element transposon insertion in cultivated rice genomes. Overexpression of RAV6 in the wild type phenocopied the Epi-rav6 phenotype. The brassinosteroid (BR) receptor BR INSENSITIVE1 and BR biosynthetic genes EBISU DWARF, DWARF11, and BR-DEFICIENT DWARF1 were ectopically expressed in Epi-rav6 plants. Also, treatment with a BR biosynthesis inhibitor restored the leaf angle defects of Epi-rav6 plants. This indicates that RAV6 affects rice leaf angle by modulating BR homeostasis and demonstrates an essential regulatory role of epigenetic modification on a key gene controlling important agricultural traits. Thus, our work identifies a unique rice epiallele, which may represent a common phenomenon in complex crop genomes. PMID:26351308

  5. Epigenetic Mutation of RAV6 Affects Leaf Angle and Seed Size in Rice1[OPEN

    PubMed Central

    Zhang, Xiangqian; Sun, Jing; Cao, Xiaofeng; Song, Xianwei

    2015-01-01

    Heritable epigenetic variants of genes, termed epialleles, can broaden genetic and phenotypic diversity in eukaryotes. Epialleles may also provide a new source of beneficial traits for crop breeding, but very few epialleles related to agricultural traits have been identified in crops. Here, we identified Epi-rav6, a gain-of-function epiallele of rice (Oryza sativa) RELATED TO ABSCISIC ACID INSENSITIVE3 (ABI3)/VIVIPAROUS1 (VP1) 6 (RAV6), which encodes a B3 DNA-binding domain-containing protein. The Epi-rav6 plants show larger lamina inclination and smaller grain size; these agronomically important phenotypes are inherited in a semidominant manner. We did not find nucleotide sequence variation of RAV6. Instead, we found hypomethylation in the promoter region of RAV6, which caused ectopic expression of RAV6 in Epi-rav6 plants. Bisulfite analysis revealed that cytosine methylation of four CG and two CNG loci within a continuous 96-bp region plays essential roles in regulating RAV6 expression; this region contains a conserved miniature inverted repeat transposable element transposon insertion in cultivated rice genomes. Overexpression of RAV6 in the wild type phenocopied the Epi-rav6 phenotype. The brassinosteroid (BR) receptor BR INSENSITIVE1 and BR biosynthetic genes EBISU DWARF, DWARF11, and BR-DEFICIENT DWARF1 were ectopically expressed in Epi-rav6 plants. Also, treatment with a BR biosynthesis inhibitor restored the leaf angle defects of Epi-rav6 plants. This indicates that RAV6 affects rice leaf angle by modulating BR homeostasis and demonstrates an essential regulatory role of epigenetic modification on a key gene controlling important agricultural traits. Thus, our work identifies a unique rice epiallele, which may represent a common phenomenon in complex crop genomes. PMID:26351308

  6. A Naturally Occurring Mutation of the Opsin Gene (T4R) in Dogs Affects Glycosylation and Stability of the G Protein-coupled Receptor*

    PubMed Central

    Zhu, Li; Jang, Geeng-Fu; Jastrzebska, Beata; Filipek, Sławomir; Pearce-Kelling, Susan E.; Aguirre, Gustavo D.; Stenkamp, Ronald E.; Acland, Gregory M.; Palczewski, Krzysztof

    2005-01-01

    Rho (rhodopsin; opsin plus 11-cis-retinal) is a prototypical G protein-coupled receptor responsible for the capture of a photon in retinal photoreceptor cells. A large number of mutations in the opsin gene associated with autosomal dominant retinitis pigmentosa have been identified. The naturally occurring T4R opsin mutation in the English mastiff dog leads to a progressive retinal degeneration that closely resembles human retinitis pigmentosa caused by the T4K mutation in the opsin gene. Using genetic approaches and biochemical assays, we explored the properties of the T4R mutant protein. Employing immunoaffinity-purified Rho from affected RHOT4R/T4R dog retina, we found that the mutation abolished glycosylation at Asn2, whereas glycosylation at Asn15 was unaffected, and the mutant opsin localized normally to the rod outer segments. Moreover, we found that T4R Rho* lost its chromophore faster as measured by the decay of meta-rhodopsin II and that it was less resistant to heat denaturation. Detergent-solubilized T4R opsin regenerated poorly and interacted abnormally with the G protein transducin (Gt). Structurally, the mutation affected mainly the “plug” at the intradiscal (extracellular) side of Rho, which is possibly responsible for protecting the chromophore from the access of bulk water. The T4R mutation may represent a novel molecular mechanism of degeneration where the unliganded form of the mutant opsin exerts a detrimental effect by losing its structural integrity. PMID:15459196

  7. Whole-Genome Sequencing and iPLEX MassARRAY Genotyping Map an EMS-Induced Mutation Affecting Cell Competition in Drosophila melanogaster

    PubMed Central

    Lee, Chang-Hyun; Rimesso, Gerard; Reynolds, David M.; Cai, Jinlu; Baker, Nicholas E.

    2016-01-01

    Cell competition, the conditional loss of viable genotypes only when surrounded by other cells, is a phenomenon observed in certain genetic mosaic conditions. We conducted a chemical mutagenesis and screen to recover new mutations that affect cell competition between wild-type and RpS3 heterozygous cells. Mutations were identified by whole-genome sequencing, making use of software tools that greatly facilitate the distinction between newly induced mutations and other sources of apparent sequence polymorphism, thereby reducing false-positive and false-negative identification rates. In addition, we utilized iPLEX MassARRAY for genotyping recombinant chromosomes. These approaches permitted the mapping of a new mutation affecting cell competition when only a single allele existed, with a phenotype assessed only in genetic mosaics, without the benefit of complementation with existing mutations, deletions, or duplications. These techniques expand the utility of chemical mutagenesis and whole-genome sequencing for mutant identification. We discuss mutations in the Atm and Xrp1 genes identified in this screen. PMID:27574103

  8. G364R mutation of MCM4 detected in human skin cancer cells affects DNA helicase activity of MCM4/6/7 complex.

    PubMed

    Ishimi, Yukio; Irie, Daiki

    2015-06-01

    A number of gene mutations are detected in cells derived from human cancer tissues, but roles of these mutations in cancer cell development are largely unknown. We examined G364R mutation of MCM4 detected in human skin cancer cells. Formation of MCM4/6/7 complex is not affected by the mutation. Consistent with this notion, the binding to MCM6 is comparable between the mutant MCM4 and wild-type MCM4. Nuclear localization of this mutant MCM4 expressed in HeLa cells supports this conclusion. Purified MCM4/6/7 complex containing the G364R MCM4 exhibited similar levels of single-stranded DNA binding and ATPase activities to the complex containing wild-type MCM4. However, the mutant complex showed only 30-50% of DNA helicase activity of the wild-type complex. When G364R MCM4 was expressed in HeLa cells, it was fractionated into nuclease-sensitive chromatin fraction, similar to wild-type MCM4. These results suggest that this mutation does not affect assembly of MCM2-7 complex on replication origins but it interferes some step at function of MCM2-7 helicase. Thus, this mutation may contribute to cancer cell development by disturbing DNA replication.

  9. Respiratory phenotypes are distinctly affected in mice with common Rett syndrome mutations MeCP2 T158A and R168X.

    PubMed

    Bissonnette, J M; Schaevitz, L R; Knopp, S J; Zhou, Z

    2014-05-16

    Respiratory disturbances are a primary phenotype of the neurological disorder, Rett syndrome (RTT), caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2). Mouse models generated with null mutations in Mecp2 mimic respiratory abnormalities in RTT girls. Large deletions, however, are seen in only ∼10% of affected human individuals. Here we characterized respiration in heterozygous females from two mouse models that genetically mimic common RTT point mutations, a missense mutation T158A (Mecp2(T158A/)(+)) or a nonsense mutation R168X (Mecp2(R168X/+)). MeCP2 T158A shows decreased binding to methylated DNA, while MeCP2 R168X retains the capacity to bind methylated DNA but lacks the ability to recruit complexes required for transcriptional repression. We found that both Mecp2(T158A/+) and Mecp2(R168X/+) heterozygotes display augmented hypoxic ventilatory responses and depressed hypercapnic responses, compared to wild-type controls. Interestingly, the incidence of apnea was much greater in Mecp2(R168X/+) heterozygotes, 189 per hour, than Mecp2(T158A/+) heterozygotes, 41 per hour. These results demonstrate that different RTT mutations lead to distinct respiratory phenotypes, suggesting that characterization of the respiratory phenotype may reveal functional differences between MeCP2 mutations and provide insights into the pathophysiology of RTT.

  10. Use of advanced recombinant lines to study the impact and potential of mutations affecting starch synthesis in barley☆

    PubMed Central

    Howard, Thomas P.; Fahy, Brendan; Leigh, Fiona; Howell, Phil; Powell, Wayne; Greenland, Andy; Trafford, Kay; Smith, Alison M.

    2014-01-01

    The effects on barley starch and grain properties of four starch synthesis mutations were studied during the introgression of the mutations from diverse backgrounds into an elite variety. The lys5f (ADPglucose transporter), wax (granule-bound starch synthase), isa1 (debranching enzyme isoamylase 1) and sex6 (starch synthase IIa) mutations were introgressed into NFC Tipple to give mutant and wild-type BC2F4 families with different genomic contributions of the donor parent. Comparison of starch and grain properties between the donor parents, the BC2F4 families and NFC Tipple allowed the effects of the mutations to be distinguished from genetic background effects. The wax and sex6 mutations had marked effects on starch properties regardless of genetic background. The sex6 mutation conditioned low grain weight and starch content, but the wax mutation did not. The lys5 mutation conditioned low grain weight and starch content, but exceptionally high β-glucan contents. The isa1 mutation promotes synthesis of soluble α-glucan (phytoglycogen). Its introgression into NFC Tipple increased grain weight and total α-glucan content relative to the donor parent, but reduced the ratio of phytoglycogen to starch. This study shows that introgression of mutations into a common, commercial background provides new insights that could not be gained from the donor parent. PMID:24748716

  11. Insights on the Impact of Arbuscular Mycorrhizal Symbiosis on Tomato Tolerance to Water Stress.

    PubMed

    Chitarra, Walter; Pagliarani, Chiara; Maserti, Biancaelena; Lumini, Erica; Siciliano, Ilenia; Cascone, Pasquale; Schubert, Andrea; Gambino, Giorgio; Balestrini, Raffaella; Guerrieri, Emilio

    2016-06-01

    Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development in the future of a more sustainable next-generation agriculture. The best understood function in symbiosis is an improvement in plant mineral nutrient acquisition, as exchange for carbon compounds derived from the photosynthetic process: this can enhance host growth and tolerance to environmental stresses, such as water stress (WS). However, physiological and molecular mechanisms occurring in arbuscular mycorrhiza-colonized plants and directly involved in the mitigation of WS effects need to be further investigated. The main goal of this work is to verify the potential impact of AM symbiosis on the plant response to WS To this aim, the effect of two AM fungi (Funneliformis mosseae and Rhizophagus intraradices) on tomato (Solanum lycopersicum) under the WS condition was studied. A combined approach, involving ecophysiological, morphometric, biochemical, and molecular analyses, has been used to highlight the mechanisms involved in plant response to WS during AM symbiosis. Gene expression analyses focused on a set of target genes putatively involved in the plant response to drought, and in parallel, we considered the expression changes induced by the imposed stress on a group of fungal genes playing a key role in the water-transport process. Taken together, the results show that AM symbiosis positively affects the tolerance to WS in tomato, with a different plant response depending on the AM fungi species involved. PMID:27208301

  12. The effect of pseudo-microgravity on the symbiosis of plants and microorganisms

    NASA Astrophysics Data System (ADS)

    Tomita-Yokotani, Kaori; Maki, Asano; Aoki, Toshio; Tamura, Kenji; Wada, Hidenori; Hashimoto, Hirofumi; Yamashita, Masamichi

    The symbiosis of plants and microorganisms is important to conduct agriculture under space environment. However, we have less knowledge on whether this kind of symbiosis can be established under space condition. We examined the functional compounds responsible to symbiosis between rhizobiaum and Lotus japonicus as a model of symbiotic combination. The existence of the substances for their symbiosis, some flavonoids, have already been known from the study of gene expression, but the detail structures have not yet been elucidated. Pseudomicrogravity was generated by the 3D-clinorotation. Twenty flavonoids were found in the extracts of 16 days plants of Lotus japonicus grown under the normal gravity by HPLC. Content of two flavonoids among them was affected by the infection of Mesorhizobium loti to them. It has a possibility that the two flavonoids were key substances for their combination process. The productions of those flavonoids were confirmed also under the pseudo-microgravity. The amount of one flavonoid was increased by both infection of rhizobium and exposure to the normal and pseudo-micro gravity. Chemical species of these flavonoids were identified by LC- ESI/MS and spectroscopic analysis. To show the effects of pseudo-microgravity on the gene expression, enzymic activities related to the functional compounds are evaluated after the rhizobial infection.

  13. [Effect of five fungicides on growth of Glycyrrhiza uralensis and efficiency of mycorrhizal symbiosis].

    PubMed

    Li, Peng-ying; Yang, Guang; Zhou, Xiu-teng; Zhou, Liane-yun; Shao, Ai-juan; Chen, Mei-lan

    2015-12-01

    In order to obtain the fungicides with minimal impact on efficiency of mycorrhizal symbiosis, the effect of five fungicides including polyoxins, jinggangmycins, thiophanate methylate, chlorothalonil and carbendazim on the growth of medicinal plant and efficiency of mycorrhizal symbiosis were studied. Pot cultured Glycyrrhiza uralensis was treated with different fungicides with the concentration that commonly used in the field. 60 d after treated with fungicides, infection rate, infection density, biomass indexes, photosyn- thetic index and the content of active component were measured. Experimental results showed that carbendazim had the strongest inhibition on mycorrhizal symbiosis effect. Carbendazim significantly inhibited the mycorrhizal infection rate, significantly suppressed the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. Polyoxins showed the lowest inhibiting affection. Polyoxins had no significant effect on mycorrhizal infection rate, the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. The other three fungicides also had an inhibitory effect on efficiency of mycorrhizal symbiosis, and the inhibition degrees were all between polyoxins's and carbendazim's. The author considered that fungicide's inhibition degree on mycorrhizal effect might be related with the species of fungicides, so the author suggested that the farmer should try to choose bio-fungicides like polyoxins.

  14. [Effect of five fungicides on growth of Glycyrrhiza uralensis and efficiency of mycorrhizal symbiosis].

    PubMed

    Li, Peng-ying; Yang, Guang; Zhou, Xiu-teng; Zhou, Liane-yun; Shao, Ai-juan; Chen, Mei-lan

    2015-12-01

    In order to obtain the fungicides with minimal impact on efficiency of mycorrhizal symbiosis, the effect of five fungicides including polyoxins, jinggangmycins, thiophanate methylate, chlorothalonil and carbendazim on the growth of medicinal plant and efficiency of mycorrhizal symbiosis were studied. Pot cultured Glycyrrhiza uralensis was treated with different fungicides with the concentration that commonly used in the field. 60 d after treated with fungicides, infection rate, infection density, biomass indexes, photosyn- thetic index and the content of active component were measured. Experimental results showed that carbendazim had the strongest inhibition on mycorrhizal symbiosis effect. Carbendazim significantly inhibited the mycorrhizal infection rate, significantly suppressed the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. Polyoxins showed the lowest inhibiting affection. Polyoxins had no significant effect on mycorrhizal infection rate, the actual photosynthetic efficiency of G. uralensis and the most indicators of biomass. The other three fungicides also had an inhibitory effect on efficiency of mycorrhizal symbiosis, and the inhibition degrees were all between polyoxins's and carbendazim's. The author considered that fungicide's inhibition degree on mycorrhizal effect might be related with the species of fungicides, so the author suggested that the farmer should try to choose bio-fungicides like polyoxins. PMID:27141668

  15. Insights on the Impact of Arbuscular Mycorrhizal Symbiosis on Tomato Tolerance to Water Stress1[OPEN

    PubMed Central

    Siciliano, Ilenia

    2016-01-01

    Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development in the future of a more sustainable next-generation agriculture. The best understood function in symbiosis is an improvement in plant mineral nutrient acquisition, as exchange for carbon compounds derived from the photosynthetic process: this can enhance host growth and tolerance to environmental stresses, such as water stress (WS). However, physiological and molecular mechanisms occurring in arbuscular mycorrhiza-colonized plants and directly involved in the mitigation of WS effects need to be further investigated. The main goal of this work is to verify the potential impact of AM symbiosis on the plant response to WS. To this aim, the effect of two AM fungi (Funneliformis mosseae and Rhizophagus intraradices) on tomato (Solanum lycopersicum) under the WS condition was studied. A combined approach, involving ecophysiological, morphometric, biochemical, and molecular analyses, has been used to highlight the mechanisms involved in plant response to WS during AM symbiosis. Gene expression analyses focused on a set of target genes putatively involved in the plant response to drought, and in parallel, we considered the expression changes induced by the imposed stress on a group of fungal genes playing a key role in the water-transport process. Taken together, the results show that AM symbiosis positively affects the tolerance to WS in tomato, with a different plant response depending on the AM fungi species involved. PMID:27208301

  16. Pleiotropic Mutations at the TUP1 Locus That Affect the Expression of Mating-Type-Dependent Functions in SACCHAROMYCES CEREVISIAE.

    PubMed

    Lemontt, J F; Fugit, D R; Mackay, V L

    1980-04-01

    The umr7-1 mutation, previously identified in a set of mutants that had been selected for defective UV-induced mutagenesis at CAN1, affects other cellular functions, including many of those regulated by the mating-type locus (MAT) in heterothallic Saccharomyces cerevisiae. The recessive umr7-1 allele, mapping approximately 20 cM distal to thr4 on chromosome III, causes clumpy growth in both a and alpha cells and has no apparent effect on a mating functions. However, alpha umr7 meiotic segregants fail to express several alpha-specific functions (e.g., high-frequency conjugation with a strains, secretion of the hormone alpha-factor and response to the hormone a-factor). In addition, alpha umr7 cells exhibit some a-specific characteristics, such as the barrier phenotype (Bar(+)) that prevents diffusion of alpha-factor and an increased mating frequency with alpha strains. The most striking property of alpha umr7 strains is their altered morphology, in which mitotic cells develop an asymmetric pear shape, like that of normal a cells induced to form "shmoos" by interaction with alpha-factor. Some a/alpha-specific diploid functions are also affected by umr7; instead of polar budding patterns, a/alpha umr7/umr7 diploids have medial budding like a/a, alpha/alpha and haploid strains. Moreover, a/alpha umr7/umr7 diploids have lost the ability to sporulate and are Bar(+) like a or a/a strains. Revertant studies indicate that umr7-1 is a single point mutation. The umr7 mutant fails to complement mutants of both tup1 (selected for deoxythymidine monophosphate utilization) and cyc9 (selected for high iso-2-cytochrome c levels), and all three isolates have similar genetic and phenotypic properties. It is suggested that the product of this gene plays some common central role in the complex regulation of the expression of both MAT-dependent and MAT-independent functions.

  17. Speciation by Symbiosis: the Microbiome and Behavior

    PubMed Central

    Shropshire, J. Dylan

    2016-01-01

    ABSTRACT Species are fundamental units of comparison in biology. The newly discovered importance and ubiquity of host-associated microorganisms are now stimulating work on the roles that microbes can play in animal speciation. We previously synthesized the literature and advanced concepts of speciation by symbiosis with notable attention to hybrid sterility and lethality. Here, we review recent studies and relevant data on microbes as players in host behavior and behavioral isolation, emphasizing the patterns seen in these analyses and highlighting areas worthy of additional exploration. We conclude that the role of microbial symbionts in behavior and speciation is gaining exciting traction and that the holobiont and hologenome concepts afford an evolving intellectual framework to promote research and intellectual exchange between disciplines such as behavior, microbiology, genetics, symbiosis, and speciation. Given the increasing centrality of microbiology in macroscopic life, microbial symbiosis is arguably the most neglected aspect of animal and plant speciation, and studying it should yield a better understanding of the origin of species. PMID:27034284

  18. The perplexed and confused mutations affect distinct stages during the transition from proliferating to post-mitotic cells within the zebrafish retina.

    PubMed

    Link, B A; Kainz, P M; Ryou, T; Dowling, J E

    2001-08-15

    To identify and study genes essential for vertebrate retinal development, we are screening zebrafish embryos for mutations that disrupt retinal histogenesis. Key steps in retinogenesis include withdrawal from mitosis by multipotent neuroepithelial cells, specification to particular cell types, migration to the appropriate laminar positions, and molecular and morphological differentiation. In this study, we have identified two recessive mutations that affect the transition of proliferating neuroepithelial cells to postmitotic retinal cells. Both the perplexed and confused mutant phenotypes were initially detectable when the first retinal neuroepithelial cells began to leave the cell cycle. At this time, each mutant retina showed increased cell death and a lack of morphological differentiation. Cell death was found to be apoptotic in both perplexed and confused retinas based on TUNEL analysis and activation of caspase-3. TUNEL-phosphoRb-BrdU colocalization studies indicated that the perplexed mutation caused death in cells transitioning from a proliferative to postmitotic state. For the confused mutation, TUNEL-phosphoRb-BrdU analysis revealed that only a subset of postmitotic cells were induced to activate apoptosis. Mosaic analysis demonstrated that within the retina the perplexed mutation functions noncell-autonomously. Furthermore, whole lens or eye cup transplantations indicated that the retinal defect was intrinsic to the retina. Mosaic analysis with confused embryos showed this mutation acts cell-autonomously. From these studies, we conclude that the perplexed and confused genes are essential at distinct stages during the transition from proliferating to postmitotic cells within the zebrafish retina. PMID:11476583

  19. A temperature-sensitive mutation affecting cilia regeneration, nuclear development, and the cell cycle of Tetrahymena thermophila is rescued by cytoplasmic exchange

    SciTech Connect

    Pennock, D.G.; Thatcher, T.; Gorovsky, M.A. )

    1988-07-01

    A temperature-sensitive mutation was isolated that blocks cilia regeneration and arrests growth in Tetrahymena thermophila. Protein and RNA synthesis and ATP production appeared to be largely unaffected at the restrictive temperature, suggesting that the mutation is specific for cilia regeneration and growth. At the restrictive temperature, mutant cells arrested at a specific point in the cell cycle, after macronuclear S phase and shortly before micronuclear mitosis. Arrested cels did not undergo nuclear divisions, DNA replication, or cytokinesis, so the mutation appears to cause true cell cycle arrest. Surprisingly, the mutation des not appear to affect micronuclear mitosis directly but rather some event(s) prior to micronuclear mitosis that must be completed before cells can complete the cell cycle. The cell cycle arrest was transiently complemented by wild-type cytoplasm exchanged during conjugation with a wild-type cell. Each starved, wild-type cell apparently contained enough rescuing factor to support an average of six cell divisions. Thus, this mutation affects assembly and/or function of at least one but not al of the microtubule-based structures in T. thermophila.

  20. Molecular characterization of 7 patients affected by dys- or hypo-dysfibrinogenemia: Identification of a novel mutation in the fibrinogen Bbeta chain causing a gain of glycosylation.

    PubMed

    Asselta, Rosanna; Robusto, Michela; Platé, Manuela; Santoro, Cristina; Peyvandi, Flora; Duga, Stefano

    2015-07-01

    Fibrinogen is a hexameric glycoprotein consisting of two sets of three polypeptides (the Aα, Bβ, and γ chains, encoded by the three genes FGA, FGB, and FGG). It is involved in the final phase of the coagulation process, being the precursor of the fibrin monomers necessary for the formation of the hemostatic plug. Rare inherited fibrinogen disorders can manifest as quantitative deficiencies, qualitative defects, or both. In particular, dysfibrinogenemia and hypo-dysfibrinogenemia are characterized by reduced functional activity associated with normal or reduced antigen levels, and are usually determined by heterozygous mutations affecting any of the three fibrinogen genes. In this study, we investigated the genetic basis of dys- and hypo-dysfibrinogenemia in seven unrelated patients. Mutational screening disclosed six different variants, two of which novel (FGB-p.Asp185Asn and FGG-p.Asn230Lys). The molecular characterization of the FGG-p.Asn230Lys mutation, performed by transient expression experiments of the recombinant mutant protein, demonstrated that it induces an almost complete impairment in fibrinogen secretion, according to a molecular mechanism often associated with quantitative fibrinogen disorders. Conversely, the FGB-p.Asp185Asn variant was demonstrated to be a gain-of-glycosylation mutation leading to a hyperglycosylation of the Bβ chain, not affecting fibrinogen assembly and secretion. To our knowledge, this is the second gain-of-glycosylation mutation involving the FGB gene.

  1. Missense mutations that cause Van der Woude syndrome and popliteal pterygium syndrome affect the DNA-binding and transcriptional activation functions of IRF6.

    PubMed

    Little, Hayley J; Rorick, Nicholas K; Su, Ling-I; Baldock, Clair; Malhotra, Saimon; Jowitt, Tom; Gakhar, Lokesh; Subramanian, Ramaswamy; Schutte, Brian C; Dixon, Michael J; Shore, Paul

    2009-02-01

    Cleft lip and cleft palate (CLP) are common disorders that occur either as part of a syndrome, where structures other than the lip and palate are affected, or in the absence of other anomalies. Van der Woude syndrome (VWS) and popliteal pterygium syndrome (PPS) are autosomal dominant disorders characterized by combinations of cleft lip, CLP, lip pits, skin-folds, syndactyly and oral adhesions which arise as the result of mutations in interferon regulatory factor 6 (IRF6). IRF6 belongs to a family of transcription factors that share a highly conserved N-terminal, DNA-binding domain and a less well-conserved protein-binding domain. To date, mutation analyses have suggested a broad genotype-phenotype correlation in which missense and nonsense mutations occurring throughout IRF6 may cause VWS; in contrast, PPS-causing mutations are highly associated with the DNA-binding domain, and appear to preferentially affect residues that are predicted to interact directly with the DNA. Nevertheless, this genotype-phenotype correlation is based on the analysis of structural models rather than on the investigation of the DNA-binding properties of IRF6. Moreover, the effects of mutations in the protein interaction domain have not been analysed. In the current investigation, we have determined the sequence to which IRF6 binds and used this sequence to analyse the effect of VWS- and PPS-associated mutations in the DNA-binding domain of IRF6. In addition, we have demonstrated that IRF6 functions as a co-operative transcriptional activator and that mutations in the protein interaction domain of IRF6 disrupt this activity. PMID:19036739

  2. Characterization of a Disease-associated Mutation Affecting a Putative Splicing Regulatory Element in Intron 6b of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene*

    PubMed Central

    Faà, Valeria; Incani, Federica; Meloni, Alessandra; Corda, Denise; Masala, Maddalena; Baffico, A. Maria; Seia, Manuela; Cao, Antonio; Rosatelli, M. Cristina

    2009-01-01

    Cystic fibrosis (CF) is a common recessive disorder caused by >1600 mutations in the CF transmembrane conductance regulator (CFTR) gene. About 13% of CFTR mutations are classified as “splicing mutations,” but for almost 40% of these, their role in affecting the pre-mRNA splicing of the gene is not yet defined. In this work, we describe a new splicing mutation detected in three unrelated Italian CF patients. By DNA analyses and mRNA studies, we identified the c.1002–1110_1113delTAAG mutation localized in intron 6b of the CFTR gene. At the mRNA level, this mutation creates an aberrant inclusion of a sequence of 101 nucleotides between exons 6b and 7. This sequence corresponds to a portion of intron 6b and resembles a cryptic exon because it is characterized by an upstream ag and a downstream gt sequence, which are most probably recognized as 5′- and 3′-splice sites by the spliceosome. Through functional analysis of this splicing defect, we show that this mutation abolishes the interaction of the splicing regulatory protein heterogeneous nuclear ribonucleoprotein A2/B1 with an intronic splicing regulatory element and creates a new recognition motif for the SRp75 splicing factor, causing activation of the cryptic exon. Our results show that the c.1002–1110_1113delTAAG mutation creates a new intronic splicing regulatory element in intron 6b of the CFTR gene exclusively recognized by SRp75. PMID:19759008

  3. Mutations in elongation factor EF-1 alpha affect the frequency of frameshifting and amino acid misincorporation in Saccharomyces cerevisiae.

    PubMed

    Sandbaken, M G; Culbertson, M R

    1988-12-01

    A mutational analysis of the eukaryotic elongation factor EF-1 alpha indicates that this protein functions to limit the frequency of errors during genetic code translation. We found that both amino acid misincorporation and reading frame errors are controlled by EF-1 alpha. In order to examine the function of this protein, the TEF2 gene, which encodes EF-1 alpha in Saccharomyces cerevisiae, was mutagenized in vitro with hydroxylamine. Sixteen independent TEF2 alleles were isolated by their ability to suppress frameshift mutations. DNA sequence analysis identified eight different sites in the EF-1 alpha protein that elevate the frequency of mistranslation when mutated. These sites are located in two different regions of the protein. Amino acid substitutions located in or near the GTP-binding and hydrolysis domain of the protein cause suppression of frameshift and nonsense mutations. These mutations may effect mistranslation by altering the binding or hydrolysis of GTP. Amino acid substitutions located adjacent to a putative aminoacyl-tRNA binding region also suppress frameshift and nonsense mutations. These mutations may alter the binding of aminoacyl-tRNA by EF-1 alpha. The identification of frameshift and nonsense suppressor mutations in EF-1 alpha indicates a role for this protein in limiting amino acid misincorporation and reading frame errors. We suggest that these types of errors are controlled by a common mechanism or closely related mechanisms. PMID:3066688

  4. Persistence time of loss-of-function mutations at nonessential loci affecting eye color in Drosophila melanogaster.

    PubMed

    Yampolsky, Lev Y; Allen, Chenoa; Shabalina, Svetlana A; Kondrashov, Alexey S

    2005-12-01

    Persistence time of a mutant allele, the expected number of generations before its elimination from the population, can be estimated as the ratio of the number of segregating mutations per individual over the mutation rate per generation. We screened two natural populations of Drosophila melanogaster for mutations causing clear-cut eye phenotypes and detected 25 mutant alleles, falling into 19 complementation groups, in 1164 haploid genomes, which implies 0.021 eye mutations/genome. The de novo haploid mutation rate for the same set of loci was estimated as 2 x 10(-4) in a 10-generation mutation-accumulation experiment. Thus, the average persistence time of all mutations causing clear-cut eye phenotypes is approximately 100 generations (95% confidence interval: 61-219). This estimate shows that the strength of selection against phenotypically drastic alleles of nonessential loci is close to that against recessive lethals. In both cases, deleterious alleles are apparently eliminated by selection against heterozygous individuals, which show no visible phenotypic differences from wild type. PMID:16118190

  5. Mutations in exons of the CYP17-II gene affect sex steroid concentration in male Japanese flounder ( Paralichthys olivaceus)

    NASA Astrophysics Data System (ADS)

    Ma, Ruiqin; He, Feng; Wen, Haishen; Li, Jifang; Shi, Bao; Shi, Dan; Liu, Miao; Mu, Weijie; Zhang, Yuanqing; Hu, Jian; Han, Weiguo; Zhang, Jianan; Wang, Qingqing; Yuan, Yuren; Liu, Qun

    2012-03-01

    As a specific gene of fish, cytochrome P450c17-II ( CYP17-II) gene plays a key role in the growth, development an reproduction level of fish. In this study, the single-stranded conformational polymorphism (SSCP) technique was used to characterize polymorphisms within the coding region of CYP17-II gene in a population of 75 male Japanese flounder ( Paralichthys olivaceus). Three single nucleotide polymorphisms (SNPs) were identified in CYP17-II gene of Japanese flounder. They were c.G594A (p.G188R), c.G939A and c.G1502A (p.G490D). SNP1 (c.G594A), located in exon 4 of CYP17-II gene, was significantly associated with gonadosomatic index (GSI). Individuals with genotype GG of SNP1 had significantly lower GSI ( P < 0.05) than those with genotype AA or AG. SNP2 (c.G939A) located at the CpG island of CYP17-II gene. The mutation changed the methylation of exon 6. Individuals with genotype AA of SNP2 had significantly lower serum testosterone (T) level and hepatosomatic index (HSI) compared to those with genotype GG. The results suggested that SNP2 could influence the reproductive endocrine of male Japanese flounder. However, the SNP3 (c.G1502A) located in exon 9 did not affect the four measured reproductive traits. This study showed that CYP17-II gene could be a potentially useful candidate gene for the research of genetic breeding and physiological aspects of Japanese flounder.

  6. Recurrent Dominant Mutations Affecting Two Adjacent Residues in the Motor Domain of the Monomeric Kinesin KIF22 Result in Skeletal Dysplasia and Joint Laxity

    PubMed Central

    Boyden, Eric D.; Campos-Xavier, A. Belinda; Kalamajski, Sebastian; Cameron, Trevor L.; Suarez, Philippe; Tanackovich, Goranka; Andria, Generoso; Ballhausen, Diana; Briggs, Michael D.; Hartley, Claire; Cohn, Daniel H.; Davidson, H. Rosemarie; Hall, Christine; Ikegawa, Shiro; Jouk, Pierre-Simon; König, Rainer; Megarbané, André; Nishimura, Gen; Lachman, Ralph S.; Mortier, Geert; Rimoin, David L.; Rogers, R. Curtis; Rossi, Massimiliano; Sawada, Hirotake; Scott, Richard; Unger, Sheila; Valadares, Eugenia Ribeiro; Bateman, John F.; Warman, Matthew L.; Superti-Furga, Andrea; Bonafé, Luisa

    2011-01-01

    Spondyloepimetaphyseal dysplasia with joint laxity, leptodactylic type (lepto-SEMDJL, aka SEMDJL, Hall type), is an autosomal dominant skeletal disorder that, in spite of being relatively common among skeletal dysplasias, has eluded molecular elucidation so far. We used whole-exome sequencing of five unrelated individuals with lepto-SEMDJL to identify mutations in KIF22 as the cause of this skeletal condition. Missense mutations affecting one of two adjacent amino acids in the motor domain of KIF22 were present in 20 familial cases from eight families and in 12 other sporadic cases. The skeletal and connective tissue phenotype produced by these specific mutations point to functions of KIF22 beyond those previously ascribed functions involving chromosome segregation. Although we have found Kif22 to be strongly upregulated at the growth plate, the precise pathogenetic mechanisms remain to be elucidated. PMID:22152678

  7. Tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) rapidly identified a critical missense mutation (P236T) of bovine ACADVL gene affecting growth traits.

    PubMed

    Zhang, Sihuan; Dang, Yonglong; Zhang, Qingfeng; Qin, Qiaomei; Lei, Chuzhao; Chen, Hong; Lan, Xianyong

    2015-04-01

    Acyl-CoA dehydrogenase, very long chain (ACADVL), encoding ACADVL protein, targets the inner mitochondrial membrane where it catalyzes the first step of the mitochondrial fatty acid beta-oxidation pathway and plays an important role in body metabolism and oxidation of long chain fatty acid releasing energy. Tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) is an easy-to-operate, rapid, inexpensive, and exact method for SNP genotyping. Herein, T-ARMS-PCR was carried out to detect a critical missense mutation (AC_000176:g.2885C>A; Pro236Thr) within the ACADVL gene in 644 individuals from two cattle breeds. In order to evaluate the accuracy of the T-ARMS-PCR at this locus, the genotype of the sampled individuals was also identified by PCR-RFLP. The concordance between these two methods was 98.76%. Statistical analysis showed that the bovine ACADVL gene had a significant effect on chest width (P<0.05), chest depth (P<0.05), and hip width (P<0.05) in the Qinchuan breed. The cattle with AA genotype had superior growth traits compared to cattle with AC and/or CC genotypes. The "A" allele had positive effects on growth traits. Therefore, T-ARMS-PCR can replace PCR-RFLP for rapid genotyping of this mutation, which could be used as a DNA marker for selecting individuals with superior growth traits in the Qinchuan breed. These findings contribute to breeding and genetics in beef cattle industry.

  8. Interrelationships between mycorrhizal symbiosis, soil pH and plant sex modify the performance of Antennaria dioica

    NASA Astrophysics Data System (ADS)

    Varga, Sandra; Kytöviita, Minna-Maarit

    2010-05-01

    AM symbiosis is usually beneficial for plants, but the benefits gained may depend on the soil abiotic factors. In dioecious plants, female and male individuals have different resource demands and allocation patterns. As a consequence of these differences, it is logical to assume that female and male plants differ in their relationship with arbuscular mycorrhizal (AM) fungi, although this has rarely been examined. We used a factorial greenhouse experiment to investigate whether female and male plants in the dioecious model species Antennaria dioica have a different relationship with their AM symbionts under two soil pH levels. In particular, we asked: (1) Do the sexes in A. dioica have sex-specific benefits from AM symbiosis? (2) If so, which sex gains the highest benefit? (3) How does soil pH affect the sex - AM fungal relationship? Our results indicate that the sexes responded similarly to AM symbiosis and pH when mycorrhizal benefit was examined as growth and phosphorus accumulation. However, the sexes differed in response to AM symbiosis in terms of survival, as mortality was increased due to AM symbiosis in female plants whilst the opposite effect was detected in males. The plant-AM fungus relationship was significantly affected by soil pH as lowering the soil pH decreased the benefits gained by the plants from the mycorrhizal fungus. Taken together, our findings indicate that AM symbiosis is beneficial for plants depending on the life history trait considered. In addition, interactions between plants and their AM symbionts are modified by soil factors and the sex of the plant.

  9. Correspondence regarding Ballana et al., "Mitochondrial 12S rRNA gene mutations affect RNA secondary structure and lead to variable penetrance in hearing impairment".

    PubMed

    Abreu-Silva, R S; Batissoco, A C; Lezirovitz, K; Romanos, J; Rincon, D; Auricchio, M T B M; Otto, P A; Mingroni-Netto, R C

    2006-05-12

    Ballana et al. [E. Ballana, E. Morales, R. Rabionet, B. Montserrat, M. Ventayol, O. Bravo, P. Gasparini, X. Estivill, Mitochondrial 12S rRNA gene mutations affect RNA secondary structure and lead to variable penetrance in hearing impairment, Biochem. Biophys. Res. Commun. 341 (2006) 950-957] detected a T1291C mutation segregating in a Cuban pedigree with hearing impairment. They interpreted it as probably pathogenic, based on family history, RNA conformation prediction and its absence in a control group of 95 Spanish subjects. We screened a sample of 203 deaf subjects and 300 hearing controls (110 "European-Brazilians" and 190 "African-Brazilians") for the mitochondrial mutations A1555G and T1291C. Five deaf subjects had the T1291C substitution, three isolated cases and two familial cases. In the latter, deafness was paternally inherited or segregated with the A1555G mutation. This doesn't support the hypothesis of T1291C mutation being pathogenic. Two "African-Brazilian" controls also had the T1291C substitution. Six of the seven T1291C-carriers (five deaf and two controls) had mitochondrial DNA of African origin, belonging to macrohaplogroup L1/L2. Therefore, these data point to T1291C substitution as most probably an African non-pathogenic polymorphism.

  10. Characterization of an acromesomelic dysplasia, Grebe type case: novel mutation affecting the recognition motif at the processing site of GDF5.

    PubMed

    Martinez-Garcia, Monica; Garcia-Canto, Eva; Fenollar-Cortes, Maria; Aytes, Antonio Perez; Trujillo-Tiebas, María José

    2016-09-01

    Acromesomelic dysplasia, Grebe type is a very rare skeletal dysplasia characterized by severe dwarfism with marked micromelia and deformation of the upper and lower limbs, with a proximodistal gradient of severity. CDMP1 gene mutations have been associated with Grebe syndrome, Hunter-Thompson syndrome, Du Pan syndrome and brachydactyly type C. The proband is a 4-year-old boy, born of consanguineous Pakistani parents. Radiographic imaging revealed features typical of Grebe syndrome: severe shortening of the forearms with an acromesomelic pattern following a proximodistal gradient, with distal parts more severely affected than medial parts; hypoplastic hands, with the phalangeal zone more affected than the metacarpal zone; and severe hypoplastic tibial/femoral zones in both limbs. After molecular analyses, the p.Arg377Trp variant in a homozygous pattern was identified in the CDMP1 gene in the affected child. In silico and structural analyses predicted the p.Arg377Trp amino acid change to be pathogenic. Of the 34 mutations described in the CDMP1 gene, four different missense mutations have been associated with Grebe syndrome. The CDMP1 gene encodes growth differentiation factor 5 (GDF5), which plays a role in regulation of limb patterning, joint formation and distal bone growth. Homozygous mutations in the mature domain of GDF5 result in severe limb malformations such as the Grebe type or the Hunter-Thompson type of acromesomelic chondrodysplasia. The p.Arg377Trp mutation is located within the recognition motif at the processing site of GDF5 where the sequence RRKRR changes to WRKRR. The genotype-phenotype correlation allowed not only confirmation of the clinical diagnosis but also appropriate genetic counselling to be offered to this family.

  11. Mutation of light-dependent phosphorylation sites of the Drosophila transient receptor potential-like (TRPL) ion channel affects its subcellular localization and stability.

    PubMed

    Cerny, Alexander C; Oberacker, Tina; Pfannstiel, Jens; Weigold, Sebastian; Will, Carina; Huber, Armin

    2013-05-31

    The Drosophila phototransduction cascade terminates in the opening of the ion channel transient receptor potential (TRP) and TRP-like (TRPL). Contrary to TRP, TRPL undergoes light-dependent subcellular trafficking between rhabdomeric photoreceptor membranes and an intracellular storage compartment, resulting in long term light adaptation. Here, we identified in vivo phosphorylation sites of TRPL that affect TRPL stability and localization. Quantitative mass spectrometry revealed a light-dependent change in the TRPL phosphorylation pattern. Mutation of eight C-terminal phosphorylation sites neither affected multimerization of the channels nor the electrophysiological response of flies expressing the mutated channels. However, these mutations resulted in mislocalization and enhanced degradation of TRPL after prolonged dark-adaptation. Mutation of subsets of the eight C-terminal phosphorylation sites also led to a reduction of TRPL content and partial mislocalization in the dark. This suggests that a light-dependent switch in the phosphorylation pattern of the TRPL channel mediates stable expression of TRPL in the rhabdomeres upon prolonged dark-adaptation.

  12. Modeling symbiosis by interactions through species carrying capacities

    NASA Astrophysics Data System (ADS)

    Yukalov, V. I.; Yukalova, E. P.; Sornette, D.

    2012-08-01

    We introduce a mathematical model of symbiosis between different species by taking into account the influence of each species on the carrying capacities of the others. The modeled entities can pertain to biological and ecological societies or to social, economic and financial societies. Our model includes three basic types: symbiosis with direct mutual interactions, symbiosis with asymmetric interactions, and symbiosis without direct interactions. In all cases, we provide a complete classification of all admissible dynamical regimes. The proposed model of symbiosis turned out to be very rich, as it exhibits four qualitatively different regimes: convergence to stationary states, unbounded exponential growth, finite-time singularity, and finite-time death or extinction of species.

  13. Molecular characterization of twelve patients affected by homocystinuria due to cystathionine beta-synthase deficiency: Report of two novel mutations

    SciTech Connect

    Sebastio, G.; Sperandeo, M.P.; Panico, M.

    1994-09-01

    Cystathionine beta-synthase (CBS) deficiency, an autosomal recessive disorder of sulfur amino acid metabolism (MIM 236200), causes homocystinuria and a clinical presentation involving eye, skeleton, central nervous and vascular systems. Less that 20 mutations of CBS gene have been characterized so far, G919A and T833C being the most commonly reported (36 and 9 out of 62 identified alleles, respectively). We have investigated 12 patients (10 Italians, 1 Jewish-French, 1 Italian-Spanish) and one allele of each patient has been characterized at least. T833C has been found in 7 independent alleles (6 in heterozygosity and 1 in homozygosity); G9191A, the most common mutation in Irish and North-European patients, has never been detected in the present survey. C341T (previously reported in 1 Irish-German patient only) has been found in 3 patients in heterozygosity. Besides the two new mutations previously described, i.e. G374A and C770T, we have identified two additional new missense mutations: C869T, a transition in exon 8, causing a P290L amino acid substitution, and C262T, a transition in exon 2, causing a P88S amino acid change. In 4 additional Italian patients, none of the known mutations have been detected; in one of them, a 50 bp deletion has been found in intron 11. The deletion involves the entire sequence of the second element of a tandem repeat. Conclusions: T833C is the most common panethnic mutation; C341T is relatively widespread, while G919A appears to be restricted to North-European patients. Exons 3 and 8 of the CBS gene are the hot-spots of mutational events leading to CBS deficiency.

  14. NS1 Protein Mutation I64T Affects Interferon Responses and Virulence of Circulating H3N2 Human Influenza A Viruses

    PubMed Central

    DeDiego, Marta L.; Nogales, Aitor; Lambert-Emo, Kris; Martinez-Sobrido, Luis

    2016-01-01

    ABSTRACT Influenza NS1 protein is the main viral protein counteracting host innate immune responses, allowing the virus to efficiently replicate in interferon (IFN)-competent systems. In this study, we analyzed NS1 protein variability within influenza A (IAV) H3N2 viruses infecting humans during the 2012-2013 season. We also evaluated the impact of the mutations on the ability of NS1 proteins to inhibit host innate immune responses and general gene expression. Surprisingly, a previously unidentified mutation in the double-stranded RNA (dsRNA)-binding domain (I64T) decreased NS1-mediated general inhibition of host protein synthesis by decreasing its interaction with cleavage and polyadenylation specificity factor 30 (CPSF30), leading to increased innate immune responses after viral infection. Notably, a recombinant A/Puerto Rico/8/34 H1N1 virus encoding the H3N2 NS1-T64 protein was highly attenuated in mice, most likely because of its ability to induce higher antiviral IFN responses at early times after infection and because this virus is highly sensitive to the IFN-induced antiviral state. Interestingly, using peripheral blood mononuclear cells (PBMCs) collected at the acute visit (2 to 3 days after infection), we show that the subject infected with the NS1-T64 attenuated virus has diminished responses to interferon and to interferon induction, suggesting why this subject could be infected with this highly IFN-sensitive virus. These data demonstrate the importance of influenza virus surveillance in identifying new mutations in the NS1 protein, affecting its ability to inhibit innate immune responses and, as a consequence, the pathogenicity of the virus. IMPORTANCE Influenza A and B viruses are one of the most common causes of respiratory infections in humans, causing 1 billion infections and between 300,000 and 500,000 deaths annually. Influenza virus surveillance to identify new mutations in the NS1 protein affecting innate immune responses and, as a consequence

  15. Mutations on the Switch III region and the alpha3 helix of Galpha16 differentially affect receptor coupling and regulation of downstream effectors

    PubMed Central

    Yu, May YM; Ho, Maurice KC; Liu, Andrew MF; Wong, Yung H

    2008-01-01

    Background Gα16 can activate phospholipase Cβ (PLCβ) directly like Gαq. It also couples to tetratricopeptide repeat 1 (TPR1) which is linked to Ras activation. It is unknown whether PLCβ and TPR1 interact with the same regions on Gα16. Previous studies on Gαq have defined two minimal clusters of amino acids that are essential for the coupling to PLCβ. Cognate residues in Gα16 might also be essential for interacting with PLCβ, and possibly contribute to TPR1 interaction and other signaling events. Results Alanine mutations were introduced to the two amino acid clusters (246–248 and 259–260) in the switch III region and α3 helix of Gα16. Regulations of PLCβ and STAT3 were partially weakened by each cluster mutant. A mutant harboring mutations at both clusters generally produced stronger suppressions. Activation of Jun N-terminal kinase (JNK) by Gα16 was completely abolished by mutating either clusters. Contrastingly, phosphorylations of extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) were not significantly affected by these mutations. The interactions between the mutants and PLCβ2 and TPR1 were also reduced in co-immunoprecipitation assays. Coupling between G16 and different categories of receptors was impaired by the mutations, with the effect of switch III mutations being more pronounced than those in the α3 helix. Mutations of both clusters almost completely abolished the receptor coupling and prevent receptor-induced Gβγ release. Conclusion The integrity of the switch III region and α3 helix of Gα16 is critical for the activation of PLCβ, STAT3, and JNK but not ERK or NF-κB. Binding of Gα16 to PLCβ2 or TPR1 was reduced by the mutations of either cluster. The same region could also differentially affect the effectiveness of receptor coupling to G16. The studied region was shown to bear multiple functionally important roles of G16. PMID:19025606

  16. Symbiosis of sea anemones and hermit crabs: different resource utilization patterns in the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Vafeiadou, Anna-Maria; Antoniadou, Chryssanthi; Chintiroglou, Chariton

    2012-09-01

    The small-scale distribution and resource utilization patterns of hermit crabs living in symbiosis with sea anemones were investigated in the Aegean Sea. Four hermit crab species, occupying shells of nine gastropod species, were found in symbiosis with the sea anemone Calliactis parasitica. Shell resource utilization patterns varied among hermit crabs, with Dardanus species utilizing a wide variety of shells. The size structure of hermit crab populations also affected shell resource utilization, with small-sized individuals inhabiting a larger variety of shells. Sea anemone utilization patterns varied both among hermit crab species and among residence shells, with larger crabs and shells hosting an increased abundance and biomass of C. parasitica. The examined biometric relationships suggested that small-sized crabs carry, proportionally to their weight, heavier shells and increased anemone biomass than larger ones. Exceptions to the above patterns are related either to local resource availability or to other environmental factors.

  17. An F1 genetic screen for maternal-effect mutations affecting embryonic pattern formation in Drosophila melanogaster.

    PubMed Central

    Luschnig, Stefan; Moussian, Bernard; Krauss, Jana; Desjeux, Isabelle; Perkovic, Josip; Nüsslein-Volhard, Christiane

    2004-01-01

    Large-scale screens for female-sterile mutations have revealed genes required maternally for establishment of the body axes in the Drosophila embryo. Although it is likely that the majority of components involved in axis formation have been identified by this approach, certain genes have escaped detection. This may be due to (1) incomplete saturation of the screens for female-sterile mutations and (2) genes with essential functions in zygotic development that mutate to lethality, precluding their identification as female-sterile mutations. To overcome these limitations, we performed a genetic mosaic screen aimed at identifying new maternal genes required for early embryonic patterning, including zygotically required ones. Using the Flp-FRT technique and a visible germline clone marker, we developed a system that allows efficient screening for maternal-effect phenotypes after only one generation of breeding, rather than after the three generations required for classic female-sterile screens. We identified 232 mutants showing various defects in embryonic pattern or morphogenesis. The mutants were ordered into 10 different phenotypic classes. A total of 174 mutants were assigned to 86 complementation groups with two alleles on average. Mutations in 45 complementation groups represent most previously known maternal genes, while 41 complementation groups represent new loci, including several involved in dorsoventral, anterior-posterior, and terminal patterning. PMID:15166158

  18. De novo mutation causes steroid 21-hydroxylase deficiency in one family of HLA-identical affected and unaffected siblings

    SciTech Connect

    Tajima, Toshihiro Hokkaido Univ., Sapporo ); Fujieda, K. ); Fujii-Kuriyama, Yoshiaki )

    1993-07-01

    Over 90% of congenital adrenal hyperplasia (CAH) results from 21-hydroxylase deficiency. Because the CYP21B gene is located within the HLA complex and is very tightly linked to HLA markers, HLA typing is widely used for prenatal diagnosis and identifying heterozygous family members. In the course of a study on identification of heterozygous family members with HLA typing, the authors recognized an unusual family case in which three siblings share the same HLA haplotype, and only one of them had the simple virilizing form; her two siblings did not have any endocrinological abnormalities. They investigated the mode of genetic transmission by using polymerase chain reaction and single stranded conformation polymorphism. The present study revealed that the proband was a compound heterozygote with the intron 2 mutation that causes aberrant RNA splicing and the missense mutation of exon 4, while the other siblings and the father had only one allele of a missense mutation in exon 4; the mother is a normal homozygote. This result together with DNA fingerprint analysis strongly suggest that the intron 2 mutation occurred de novo in the maternally inherited gene of the proband. This seems to be the first case of a de novo mutation of the CYP21B gene that causes CAH. 19 refs., 5 figs., 1 tab.

  19. Effect of two AMF life strategies on the tripartite symbiosis with Bradyrhizobium japonicum and soybean.

    PubMed

    Antunes, Pedro M; Deaville, Deanna; Goss, Michael J

    2006-05-01

    This study is the first in assessing the effect of soil disturbance on the contribution of arbuscular mycorrhizal fungi (AMF) with different life-history strategies to the tripartite symbiosis with soybeans and Bradyrhizobium japonicum (Kirchner) Jordan. We hypothesized that Gigaspora margarita Becker and Hall would be more affected by soil disturbance than Glomus clarum Nicol. and Schenck, and consequently, the tripartite symbiosis would develop more rapidly and lead to greater N(2) fixation in the presence of the latter. Soil pasteurization allowed the establishment of treatments with individual AMF species and soil disturbance enabled the development of contrasting root colonization potentials. In contrast, the colonization potential of B. japonicum was kept the same in all treatments. Soil disturbance significantly reduced root colonization by both AMF, with Gi. margarita being considerably more affected than G. clarum. Furthermore, the tripartite symbiosis progressed faster with G. clarum, and at 10 days after plant emergence, there was 30% more nodules when G. clarum was present compared to that when the bacterial symbiont alone was present. At flowering, the absence of soil disturbance stimulated N(2) fixation by 17% in mycorrhizal plants. However, this response was similar for both AMF.

  20. Network analysis of eight industrial symbiosis systems

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Zheng, Hongmei; Shi, Han; Yu, Xiangyi; Liu, Gengyuan; Su, Meirong; Li, Yating; Chai, Yingying

    2016-06-01

    Industrial symbiosis is the quintessential characteristic of an eco-industrial park. To divide parks into different types, previous studies mostly focused on qualitative judgments, and failed to use metrics to conduct quantitative research on the internal structural or functional characteristics of a park. To analyze a park's structural attributes, a range of metrics from network analysis have been applied, but few researchers have compared two or more symbioses using multiple metrics. In this study, we used two metrics (density and network degree centralization) to compare the degrees of completeness and dependence of eight diverse but representative industrial symbiosis networks. Through the combination of the two metrics, we divided the networks into three types: weak completeness, and two forms of strong completeness, namely "anchor tenant" mutualism and "equality-oriented" mutualism. The results showed that the networks with a weak degree of completeness were sparse and had few connections among nodes; for "anchor tenant" mutualism, the degree of completeness was relatively high, but the affiliated members were too dependent on core members; and the members in "equality-oriented" mutualism had equal roles, with diverse and flexible symbiotic paths. These results revealed some of the systems' internal structure and how different structures influenced the exchanges of materials, energy, and knowledge among members of a system, thereby providing insights into threats that may destabilize the network. Based on this analysis, we provide examples of the advantages and effectiveness of recent improvement projects in a typical Chinese eco-industrial park (Shandong Lubei).

  1. Symbiosis catalyses niche expansion and diversification

    PubMed Central

    Joy, Jeffrey B.

    2013-01-01

    Interactions between species are important catalysts of the evolutionary processes that generate the remarkable diversity of life. Symbioses, conspicuous and inherently interesting forms of species interaction, are pervasive throughout the tree of life. However, nearly all studies of the impact of species interactions on diversification have concentrated on competition and predation leaving unclear the importance of symbiotic interaction. Here, I show that, as predicted by evolutionary theories of symbiosis and diversification, multiple origins of a key innovation, symbiosis between gall-inducing insects and fungi, catalysed both expansion in resource use (niche expansion) and diversification. Symbiotic lineages have undergone a more than sevenfold expansion in the range of host-plant taxa they use relative to lineages without such fungal symbionts, as defined by the genetic distance between host plants. Furthermore, symbiotic gall-inducing insects are more than 17 times as diverse as their non-symbiotic relatives. These results demonstrate that the evolution of symbiotic interaction leads to niche expansion, which in turn catalyses diversification. PMID:23390106

  2. Osmoregulation in anthozoan-dinoflagellate symbiosis.

    PubMed

    Mayfield, Anderson B; Gates, Ruth D

    2007-05-01

    Endosymbiosis creates a unique osmotic circumstance. Hosts are not only responsible for balancing their internal osmolarity with respect to the external environment, but they must also maintain a compatible osmotic environment for their endosymbionts, which may themselves contribute to the net osmolarity of the host cell through molecular fluxes and/or exchange. Cnidarian hosts that harbor intracellular dinoflagellates (zooxanthellae) are excellent examples of such a symbiosis. These associations are characterized by the exchange of osmotically active compounds, but they are temporally stable under normal environmental conditions indicating that these osmotically driven exchanges are effectively and rapidly regulated. Although we have some knowledge about how asymbiotic anthozoans and algae osmoregulate, our understanding of the physiological mechanisms involved in regulating an intact anthozoan-dinoflagellate symbiosis is poor. Large-scale expulsion of endosymbiotic zooxanthellae, or bleaching, is currently considered to be one of the greatest threats to coral reefs worldwide. To date, there has been little consideration of the osmotic scenarios that occur when these symbioses are exposed to the conditions that normally elicit bleaching, such as increased seawater temperatures and UV radiation. Here we review what is known about osmoregulation and osmotic stress in anthozoans and dinoflagellates and discuss the osmotic implications of exposure to environmental stress in these globally distributed and ecologically important symbioses.

  3. The Microbiota, Chemical Symbiosis, and Human Disease

    PubMed Central

    Redinbo, Matthew R.

    2014-01-01

    Our understanding of mammalian-microbial mutualism has expanded by combing microbial sequencing with evolving molecular and cellular methods, and unique model systems. Here, the recent literature linking the microbiota to diseases of three of the key mammalian mucosal epithelial compartments – nasal, lung and gastrointestinal (GI) tract – is reviewed with a focus on new knowledge about the taxa, species, proteins and chemistry that promote health and impact progression toward disease. The information presented is further organized by specific diseases now associated with the microbiota:, Staphylococcus aureus infection and rhinosinusitis in the nasal-sinus mucosa; cystic fibrosis (CF), chronic obstructive pulmonary disorder (COPD), and asthma in the pulmonary tissues. For the vast and microbially dynamic GI compartment, several disorders are considered, including obesity, atherosclerosis, Crohn’s disease, ulcerative colitis, drug toxicity, and even autism. Our appreciation of the chemical symbiosis ongoing between human systems and the microbiota continues to grow, and suggest new opportunities for modulating this symbiosis using designed interventions. PMID:25305474

  4. Auxin influences strigolactones in pea mycorrhizal symbiosis.

    PubMed

    Foo, E

    2013-03-15

    Hormone interactions are essential for the control of many developmental processes, including intracellular symbioses. The interaction between auxin and the new plant hormone strigolactone in the regulation of arbuscular mycorrhizal symbiosis was examined in one of the few auxin deficient mutants available in a mycorrhizal species, the auxin-deficient bsh mutant of pea (Pisum sativum). Mycorrhizal colonisation with the fungus Glomus intraradices was significantly reduced in the low auxin bsh mutant. The bsh mutant also exhibited a reduction in strigolactone exudation and the expression of a key strigolactone biosynthesis gene (PsCCD8). Strigolactone exudation was also reduced in wild type plants when the auxin content was reduced by stem girdling. Low strigolactone levels appear to be at least partially responsible for the reduced colonisation of the bsh mutant, as application of the synthetic strigolactone GR24 could partially rescue the mycorrhizal phenotype of bsh mutants. Data presented here indicates root auxin content was correlated with strigolactone exudation in both mutant and wild type plants. Mutant studies suggest that auxin may regulate early events in the formation of arbuscular mycorrhizal symbiosis by controlling strigolactone levels, both in the rhizosphere and possibly during early root colonisation. PMID:23219475

  5. The mvp2 mutation affects the generative transition through the modification of transcriptome pattern, salicylic acid and cytokinin metabolism in Triticum monococcum.

    PubMed

    Boldizsár, Ákos; Vanková, Radomíra; Novák, Aliz; Kalapos, Balázs; Gulyás, Zsolt; Pál, Magda; Floková, Kristyna; Janda, Tibor; Galiba, Gábor; Kocsy, Gábor

    2016-09-01

    Wild type and mvp2 (maintained vegetative phase) deletion mutant T. monococcum plants incapable of flowering were compared in order to determine the effect of the deleted region of chromosome 5A on transcript profile and hormone metabolism. This region contains the vernalization1 (VRN1) gene, a major regulator of the vegetative/generative transition. Transcript profiling in the crowns of T. monococcum during the transition and the subsequent formation of flower primordia showed that 306 genes were affected by the mutation, 198 by the developmental phase and 14 by the interaction of these parameters. In addition, 546 genes were affected by two or three factors. The genes controlled by the deleted region encode transcription factors, antioxidants and enzymes of hormone, carbohydrate and amino acid metabolism. The observed changes in the expression of the gene encoding phenylalanine ammonia lyase (PAL) might indicate the effect of mvp2 mutation on the metabolism of salicylic acid, which was corroborated by the differences in 2-hydroxycinnamic acid and cinnamic acid contents in both of the leaves and crowns, and in the concentrations of salicylic acid and benzoic acid in crowns during the vegetative/generative transition. The amount and ratio of active cytokinins and their derivatives (ribosides, glucosides and phosphates) were affected by developmental changes as well as by mvp2 mutation, too. PMID:27450491

  6. LHON/MELAS overlap mutation in ND1 subunit of mitochondrial complex I affects ubiquinone binding as revealed by modeling in Escherichia coli NDH-1.

    PubMed

    Pätsi, Jukka; Maliniemi, Pilvi; Pakanen, Salla; Hinttala, Reetta; Uusimaa, Johanna; Majamaa, Kari; Nyström, Thomas; Kervinen, Marko; Hassinen, Ilmo E

    2012-02-01

    Defects in complex I due to mutations in mitochondrial DNA are associated with clinical features ranging from single organ manifestation like Leber hereditary optic neuropathy (LHON) to multiorgan disorders like mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. Specific mutations cause overlap syndromes combining several phenotypes, but the mechanisms of their biochemical effects are largely unknown. The m.3376G>A transition leading to p.E24K substitution in ND1 with LHON/MELAS phenotype was modeled here in a homologous position (NuoH-E36K) in the Escherichia coli enzyme and it almost totally abolished complex I activity. The more conservative mutation NuoH-E36Q resulted in higher apparent K(m) for ubiquinone and diminished inhibitor sensitivity. A NuoH homolog of the m.3865A>G transition, which has been found concomitantly in the overlap syndrome patient with the m.3376G>A, had only a minor effect. Consequences of a primary LHON-mutation m.3460G>A affecting the same extramembrane loop as the m.3376G>A substitution were also studied in the E. coli model and were found to be mild. The results indicate that the overlap syndrome-associated m.3376G>A transition in MTND1 is the pathogenic mutation and m.3865A>G transition has minor, if any, effect on presentation of the disease. The kinetic effects of the NuoH-E36Q mutation suggest its proximity to the putative ubiquinone binding domain in 49kD/PSST subunits. In all, m.3376G>A perturbs ubiquinone binding, a phenomenon found in LHON, and decreases the activity of fully assembled complex I as in MELAS.

  7. The LPS O-Antigen in Photosynthetic Bradyrhizobium Strains Is Dispensable for the Establishment of a Successful Symbiosis with Aeschynomene Legumes

    PubMed Central

    Busset, Nicolas; De Felice, Antonia; Chaintreuil, Clémence; Gully, Djamel; Fardoux, Joël; Romdhane, Sana; Molinaro, Antonio; Silipo, Alba; Giraud, Eric

    2016-01-01

    The photosynthetic bradyrhizobia are able to use a Nod-factor independent process to induce nitrogen-fixing nodules on some semi-aquatic Aeschynomene species. These bacteria display a unique LPS O-antigen composed of a new sugar, the bradyrhizose that is regarded as a key symbiotic factor due to its non-immunogenic character. In this study, to check this hypothesis, we isolated mutants affected in the O-antigen synthesis by screening a transposon mutant library of the ORS285 strain for clones altered in colony morphology. Over the 10,000 mutants screened, five were selected and found to be mutated in two genes, rfaL, encoding for a putative O-antigen ligase and gdh encoding for a putative dTDP-glucose 4,6-dehydratase. Biochemical analysis confirmed that the LPS of these mutants completely lack the O-antigen region. However, no effect of the mutations could be detected on the symbiotic properties of the mutants indicating that the O-antigen region of photosynthetic Bradyrhizobium strains is not required for the establishment of symbiosis with Aeschynomene. PMID:26849805

  8. The LPS O-Antigen in Photosynthetic Bradyrhizobium Strains Is Dispensable for the Establishment of a Successful Symbiosis with Aeschynomene Legumes.

    PubMed

    Busset, Nicolas; De Felice, Antonia; Chaintreuil, Clémence; Gully, Djamel; Fardoux, Joël; Romdhane, Sana; Molinaro, Antonio; Silipo, Alba; Giraud, Eric

    2016-01-01

    The photosynthetic bradyrhizobia are able to use a Nod-factor independent process to induce nitrogen-fixing nodules on some semi-aquatic Aeschynomene species. These bacteria display a unique LPS O-antigen composed of a new sugar, the bradyrhizose that is regarded as a key symbiotic factor due to its non-immunogenic character. In this study, to check this hypothesis, we isolated mutants affected in the O-antigen synthesis by screening a transposon mutant library of the ORS285 strain for clones altered in colony morphology. Over the 10,000 mutants screened, five were selected and found to be mutated in two genes, rfaL, encoding for a putative O-antigen ligase and gdh encoding for a putative dTDP-glucose 4,6-dehydratase. Biochemical analysis confirmed that the LPS of these mutants completely lack the O-antigen region. However, no effect of the mutations could be detected on the symbiotic properties of the mutants indicating that the O-antigen region of photosynthetic Bradyrhizobium strains is not required for the establishment of symbiosis with Aeschynomene.

  9. A new type of Alcaligenes eutrophus CH34 zinc resistance generated by mutations affecting regulation of the cnr cobalt-nickel resistance system.

    PubMed Central

    Collard, J M; Provoost, A; Taghavi, S; Mergeay, M

    1993-01-01

    Spontaneous mutants that were resistant to zinc were isolated from Alcaligenes eutrophus CH34 containing either the native plasmid pMOL28 or a derivative derepressed for its self-transfer, pMOL50. With the cured plasmid-free derivative of CH34, strain AE104, such mutants were not detected. The mutations, which were shown to be located in the plasmid, increased the level of the nickel and cobalt resistance determined by the cnr locus. The chromate resistance closely linked to the cnr locus was not affected by these mutations. In the Znr mutants, the resistance to zinc and nickel was constitutively expressed. Uptake studies showed that the zinc resistance in a Znr mutant resulted from reduced accumulation of zinc ions in comparison with that in the plasmid-free strain. Reduced accumulation of zinc was also observed to a lesser degree in the parental strain induced with nickel, suggesting that zinc interferes with the Ni2+ and Co2+ efflux system. A 12.2-kb EcoRI-XbaI restriction endonuclease fragment containing the cnr locus was cloned from plasmid pMOL28 harboring the mutation and shortened to an 8.5-kb EcoRI-PstI-PstI fragment conferring resistance to zinc, nickel, and cobalt. The 12.2-kb EcoRI-XbaI fragment was also reduced to a 9.7-kb BamHI fragment still encoding weak resistance to nickel and cobalt but not to zinc. Complementation studies demonstrated the recessivity of the cnr mutations with a Znr phenotype. Such mutations thus allow positive selection of mutants affected in the expression of the cnr operon. PMID:8423150

  10. ESR1 mutations affect anti-proliferative responses to tamoxifen through enhanced cross-talk with IGF signaling.

    PubMed

    Gelsomino, Luca; Gu, Guowei; Rechoum, Yassine; Beyer, Amanda R; Pejerrey, Sasha M; Tsimelzon, Anna; Wang, Tao; Huffman, Kenneth; Ludlow, Andrew; Andò, Sebastiano; Fuqua, Suzanne A W

    2016-06-01

    The purpose of this study was to address the role of ESR1 hormone-binding mutations in breast cancer. Soft agar anchorage-independent growth assay, Western blot, ERE reporter transactivation assay, proximity ligation assay (PLA), coimmunoprecipitation assay, silencing assay, digital droplet PCR (ddPCR), Kaplan-Meier analysis, and statistical analysis. It is now generally accepted that estrogen receptor (ESR1) mutations occur frequently in metastatic breast cancers; however, we do not yet know how to best treat these patients. We have modeled the three most frequent hormone-binding ESR1 (HBD-ESR1) mutations (Y537N, Y537S, and D538G) using stable lentiviral transduction in human breast cancer cell lines. Effects on growth were examined in response to hormonal and targeted agents, and mutation-specific changes were studied using microarray and Western blot analysis. We determined that the HBD-ESR1 mutations alter anti-proliferative effects to tamoxifen (Tam), due to cell-intrinsic changes in activation of the insulin-like growth factor receptor (IGF1R) signaling pathway and levels of PIK3R1/PIK3R3. The selective estrogen receptor degrader, fulvestrant, significantly reduced the anchorage-independent growth of ESR1 mutant-expressing cells, while combination treatments with the mTOR inhibitor everolimus, or an inhibitor blocking IGF1R, and the insulin receptor significantly enhanced anti-proliferative responses. Using digital drop (dd) PCR, we identified mutations at high frequencies ranging from 12 % for Y537N, 5 % for Y537S, and 2 % for D538G in archived primary breast tumors from women treated with adjuvant mono-tamoxifen therapy. The HBD-ESR1 mutations were not associated with recurrence-free or overall survival in response in this patient cohort and suggest that knowledge of other cell-intrinsic factors in combination with ESR1 mutation status will be needed determine anti-proliferative responses to Tam. PMID:27178332

  11. Mutations affecting the stability of the haemagglutinin molecule impair the immunogenicity of live attenuated H3N2 intranasal influenza vaccine candidates lacking NS1.

    PubMed

    Nakowitsch, Sabine; Wolschek, Markus; Morokutti, Alexander; Ruthsatz, Tanja; Krenn, Brigitte M; Ferko, Boris; Ferstl, Nicole; Triendl, Andrea; Muster, Thomas; Egorov, Andrej; Romanova, Julia

    2011-04-27

    The isolation and cultivation of human influenza viruses in embryonated hen eggs or cell lines often leads to amino acid substitutions in the haemagglutinin (HA) molecule. We found that the propagation of influenza A H3N2 viruses on Vero cells may trigger the appearance of HA destabilising mutations, affecting viral resistance to low pH or high temperature treatment. Two ΔNS1 reassortants, containing the HA sequences identical to the original human H3N2 influenza virus isolates were constructed. Passages of these viruses on Vero cells led to the appearance of single mutations in the HA(1) L194P or HA(2) G75R subunits that impaired virus stability. The original HA sequences and the stable phenotypes of the primary isolates were preserved if reassortants were passaged by infection at pH 5.6 and cultivation in medium at pH 6.5. Corresponding ΔNS1 reassortants were compared for their immunogenicity in ferrets upon intranasal immunisation. Vaccine candidates containing HA mutations demonstrated significantly lower immunogenicity compared to those without mutations. Thus, the retaining of the original HA sequences of human viruses during vaccine production might be crucial for the efficacy of live attenuated influenza vaccines.

  12. Reciprocal mouse and human limb phenotypes caused by gain- and loss-of-function mutations affecting Lmbr1.

    PubMed Central

    Clark, R M; Marker, P C; Roessler, E; Dutra, A; Schimenti, J C; Muenke, M; Kingsley, D M

    2001-01-01

    The major locus for dominant preaxial polydactyly in humans has been mapped to 7q36. In mice the dominant Hemimelic extra toes (Hx) and Hammertoe (Hm) mutations map to a homologous chromosomal region and cause similar limb defects. The Lmbr1 gene is entirely within the small critical intervals recently defined for both the mouse and human mutations and is misexpressed at the exact time that the mouse Hx phenotype becomes apparent during limb development. This result suggests that Lmbr1 may underlie preaxial polydactyly in both mice and humans. We have used deletion chromosomes to demonstrate that the dominant mouse and human limb defects arise from gain-of-function mutations and not from haploinsufficiency. Furthermore, we created a loss-of-function mutation in the mouse Lmbr1 gene that causes digit number reduction (oligodactyly) on its own and in trans to a deletion chromosome. The loss of digits that we observed in mice with reduced Lmbr1 activity is in contrast to the gain of digits observed in Hx mice and human polydactyly patients. Our results suggest that the Lmbr1 gene is required for limb formation and that reciprocal changes in levels of Lmbr1 activity can lead to either increases or decreases in the number of digits in the vertebrate limb. PMID:11606546

  13. Mutations affecting the cytoplasmic functions of the co-chaperone DNAJB6 cause limb-girdle muscular dystrophy

    PubMed Central

    Sarparanta, Jaakko; Jonson, Per Harald; Golzio, Christelle; Sandell, Satu; Luque, Helena; Screen, Mark; McDonald, Kristin; Stajich, Jeffrey M.; Mahjneh, Ibrahim; Vihola, Anna; Raheem, Olayinka; Penttilä, Sini; Lehtinen, Sara; Huovinen, Sanna; Palmio, Johanna; Tasca, Giorgio; Ricci, Enzo; Hackman, Peter; Hauser, Michael; Katsanis, Nicholas; Udd, Bjarne

    2012-01-01

    Limb-girdle muscular dystrophy type 1D (LGMD1D) was linked to 7q36 over a decade ago1, but its genetic cause has remained elusive. We have studied nine LGMD families from Finland, the U.S., and Italy, and identified four dominant missense mutations leading to p.Phe93Leu or p.Phe89Ile changes in the ubiquitously expressed co-chaperone DNAJB6. Functional testing in vivo showed that the mutations have a dominant toxic effect mediated specifically by the cytoplasmic isoform of DNAJB6. In vitro studies demonstrated that the mutations increase the half-life of DNAJB6, extending this effect to the wild-type protein, and reduce its protective anti-aggregation effect. Further, we show that DNAJB6 interacts with members of the CASA complex, including the myofibrillar-myopathy-causing protein BAG3. Our data provide the genetic cause of LGMD1D, suggest that the pathogenesis is mediated by defective chaperone function, and highlight how mutations expressed ubiquitously can exert their effect in a tissue-, cellular compartment-, and isoform-specific manner. PMID:22366786

  14. Cancer-associated mutations in BRC domains of BRCA2 affect homologous recombination induced by Rad51.

    PubMed

    Tal, Asaf; Arbel-Goren, Rinat; Stavans, Joel

    2009-11-13

    The tumor suppressor BRCA2 protein plays a major role in the regulation of Rad51-catalyzed homologous recombination. BRCA2 interacts with monomeric Rad51 primarily via conserved BRC domains and coordinates the formation of Rad51 filaments at double-stranded DNA (dsDNA) breaks. A number of cancer-associated mutations in BRC4 and BRC2 domains have been reported. To elucidate their effects on homologous recombination, we studied Rad51 filament formation on single-stranded DNA and dsDNA substrates and Rad51-catalyzed strand exchange, in the presence of wild-type and mutated peptides of either BRC4 or BRC2. While the wild-type BRC2 and BRC4 peptides inhibited filament formation and, thus, strand exchange, the mutated forms decreased significantly these inhibitory effects. These results are consistent with a three-dimensional model for the interface between individual BRC repeats and Rad51. We suggest that mutations at sites crucial for the association between Rad51 and BRC domains impair the ability of BRCA2 to recruit Rad51 to dsDNA breaks, hampering recombinational repair.

  15. Identification and characterization of a mutation affecting the division arrest signaling of the pheromone response pathway in Saccharomyces cerevisiae

    SciTech Connect

    Fujimura, Hiroaki Hoechst Japan Ltd., Kawagoe )

    1990-02-01

    Mating pheromones, a- and {alpha}-factors, arrest the division of cells of opposite mating types, {alpha} and a cells, respectively. The author has isolated a sterile mutant of Saccharomyces cerevisiae using EMS that is defective in division arrest in response to {alpha}-factor but not defective in morphological changes and agglutinin induction. The mutation was designated dac2 for division arrest control by mating pheromones. The dac2 mutation was closely linked to gal1 and was different from the previously identified cell type nonspecific sterile mutations (ste4, ste5, ste7, ste11, ste12, ste18, and dac1). Although dac2 cells had no phenotype in the absence of pheromones, they showed morphological alterations and divided continuously in the presence of pheromones. As a result, dac2 cells had a mating defect. The dac2 mutation could suppress the lethality caused by the disruption of the GPA1 gene. These results suggest that the DAC2 product may control the signal for G-protein-mediated cell-cycle arrest and indicate that the synchronization of haploid yeast cell cycles by mating pheromones is essential for cell fusion during conjugation.

  16. A novel group of pumilio mutations affects the asymmetric division of germline stem cells in the Drosophila ovary.

    PubMed

    Lin, H; Spradling, A C

    1997-06-01

    Germline stem cells play a pivotal role in gametogenesis; yet little is known about how they are formed, how they divide to self-renew, and how these processes are genetically controlled. Here we describe the self-renewing asymmetric division of germline stem cells in the Drosophila ovarian germline, as marked by the spectrosome, a cytoplasmic structure rich in membrane skeletal proteins. The ontogeny of the spectrosome marks the lineage of germline stem cells. We identified two new groups of mutations in which the divisional asymmetry is disrupted. The first, which we refer to as ovarette (ovt) mutations, was shown to correspond to a novel class of mutations in the pumilio locus. Since pumilio is known to posttranscriptionally repress the expression of target genes at earlier stages of germ cell development, our results suggest that a similar activity is needed to maintain germ line stem cells. We have also identified a second and novel gene, piwi, whose mutations abolish germline stem cell division.

  17. Exome and deep sequencing of clinically aggressive neuroblastoma reveal somatic mutations that affect key pathways involved in cancer progression

    PubMed Central

    Lasorsa, Vito Alessandro; Formicola, Daniela; Pignataro, Piero; Cimmino, Flora; Calabrese, Francesco Maria; Mora, Jaume; Esposito, Maria Rosaria; Pantile, Marcella; Zanon, Carlo; De Mariano, Marilena; Longo, Luca; Hogarty, Michael D.; de Torres, Carmen; Tonini, Gian Paolo; Iolascon, Achille; Capasso, Mario

    2016-01-01

    The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma. Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines. We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK. Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%. Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression. Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants. In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression. PMID:27009842

  18. Exome and deep sequencing of clinically aggressive neuroblastoma reveal somatic mutations that affect key pathways involved in cancer progression.

    PubMed

    Lasorsa, Vito Alessandro; Formicola, Daniela; Pignataro, Piero; Cimmino, Flora; Calabrese, Francesco Maria; Mora, Jaume; Esposito, Maria Rosaria; Pantile, Marcella; Zanon, Carlo; De Mariano, Marilena; Longo, Luca; Hogarty, Michael D; de Torres, Carmen; Tonini, Gian Paolo; Iolascon, Achille; Capasso, Mario

    2016-04-19

    The spectrum of somatic mutation of the most aggressive forms of neuroblastoma is not completely determined. We sought to identify potential cancer drivers in clinically aggressive neuroblastoma.Whole exome sequencing was conducted on 17 germline and tumor DNA samples from high-risk patients with adverse events within 36 months from diagnosis (HR-Event3) to identify somatic mutations and deep targeted sequencing of 134 genes selected from the initial screening in additional 48 germline and tumor pairs (62.5% HR-Event3 and high-risk patients), 17 HR-Event3 tumors and 17 human-derived neuroblastoma cell lines.We revealed 22 significantly mutated genes, many of which implicated in cancer progression. Fifteen genes (68.2%) were highly expressed in neuroblastoma supporting their involvement in the disease. CHD9, a cancer driver gene, was the most significantly altered (4.0% of cases) after ALK.Other genes (PTK2, NAV3, NAV1, FZD1 and ATRX), expressed in neuroblastoma and involved in cell invasion and migration were mutated at frequency ranged from 4% to 2%.Focal adhesion and regulation of actin cytoskeleton pathways, were frequently disrupted (14.1% of cases) thus suggesting potential novel therapeutic strategies to prevent disease progression.Notably BARD1, CHEK2 and AXIN2 were enriched in rare, potentially pathogenic, germline variants.In summary, whole exome and deep targeted sequencing identified novel cancer genes of clinically aggressive neuroblastoma. Our analyses show pathway-level implications of infrequently mutated genes in leading neuroblastoma progression. PMID:27009842

  19. MECP2e1 isoform mutation affects the form and function of neurons derived from Rett syndrome patient iPS cells.

    PubMed

    Djuric, Ugljesa; Cheung, Aaron Y L; Zhang, Wenbo; Mok, Rebecca S; Lai, Wesley; Piekna, Alina; Hendry, Jason A; Ross, P Joel; Pasceri, Peter; Kim, Dae-Sung; Salter, Michael W; Ellis, James

    2015-04-01

    MECP2 mutations cause the X-linked neurodevelopmental disorder Rett Syndrome (RTT) by consistently altering the protein encoded by the MECP2e1 alternative transcript. While mutations that simultaneously affect both MECP2e1 and MECP2e2 isoforms have been widely studied, the consequence of MECP2e1 deficiency on human neurons remains unknown. Here we report the first isoform-specific patient induced pluripotent stem cell (iPSC) model of RTT. RTTe1 patient iPS cell-derived neurons retain an inactive X-chromosome and express only the mutant allele. Single-cell mRNA analysis demonstrated they have a molecular signature of cortical neurons. Mutant neurons exhibited a decrease in soma size, reduced dendritic complexity and decreased cell capacitance, consistent with impaired neuronal maturation. The soma size phenotype was rescued cell-autonomously by MECP2e1 transduction in a level-dependent manner but not by MECP2e2 gene transfer. Importantly, MECP2e1 mutant neurons showed a dysfunction in action potential generation, voltage-gated Na(+) currents, and miniature excitatory synaptic current frequency and amplitude. We conclude that MECP2e1 mutation affects soma size, information encoding properties and synaptic connectivity in human neurons that are defective in RTT.

  20. HIV-1 Nef mutations abrogating downregulation of CD4 affect other Nef functions and show reduced pathogenicity in transgenic mice

    SciTech Connect

    Hanna, Zaher . E-mail: Zaher.Hanna@ircm.qc.ca; Priceputu, Elena; Hu, Chunyan; Vincent, Patrick; Jolicoeur, Paul

    2006-03-01

    pathologies) in respectively Nef{sup RD35/36AA} and Nef{sup D174K} Tg mice, relative to those developing in Nef{sup Wt} Tg mice. Our data suggest that the RD35/36AA and D174K mutations affect other Nef functions, namely those involved in the development of lung and kidney diseases, in addition to their known role in CD4 downregulation. Similarly, in HIV-1-infected individuals, loss of CD4 downregulation by Nef alleles may reflect their lower intrinsic pathogenicity, independently of their effects on virus replication.

  1. Mutations associated with Dent's disease affect gating and voltage dependence of the human anion/proton exchanger ClC-5.

    PubMed

    Alekov, Alexi K

    2015-01-01

    Dent's disease is associated with impaired renal endocytosis and endosomal acidification. It is linked to mutations in the membrane chloride/proton exchanger ClC-5; however, a direct link between localization in the protein and functional phenotype of the mutants has not been established until now. Here, two Dent's disease mutations, G212A and E267A, were investigated using heterologous expression in HEK293T cells, patch-clamp measurements and confocal imaging. WT and mutant ClC-5 exhibited mixed cell membrane and vesicular distribution. Reduced ion currents were measured for both mutants and both exhibited reduced capability to support endosomal acidification. Functionally, mutation G212A was capable of mediating anion/proton antiport but dramatically shifted the activation of ClC-5 toward more depolarized potentials. The shift can be explained by impeded movements of the neighboring gating glutamate Gluext, a residue that confers major part of the voltage dependence of ClC-5 and serves as a gate at the extracellular entrance of the anion transport pathway. Cell surface abundance of E267A was reduced by ~50% but also dramatically increased gating currents were detected for this mutant and accordingly reduced probability to undergoing cycles associated with electrogenic ion transport. Structurally, the gating alternations correlate to the proximity of E267A to the proton glutamate Gluin that serves as intracellular gate in the proton transport pathway and regulates the open probability of ClC-5. Remarkably, two other mammalian isoforms, ClC-3 and ClC-4, also differ from ClC-5 in gating characteristics affected by the here investigated disease-causing mutations. This evolutionary specialization, together with the functional defects arising from mutations G212A and E267A, demonstrate that the complex gating behavior exhibited by most of the mammalian CLC transporters is an important determinant of their cellular function.

  2. Fundus albipunctatus: review of the literature and report of a novel RDH5 gene mutation affecting the invariant tyrosine (p.Tyr175Phe).

    PubMed

    Skorczyk-Werner, Anna; Pawłowski, Przemysław; Michalczuk, Marta; Warowicka, Alicja; Wawrocka, Anna; Wicher, Katarzyna; Bakunowicz-Łazarczyk, Alina; Krawczyński, Maciej R

    2015-08-01

    Fundus albipunctatus (FA) is a rare, congenital form of night blindness with rod system impairment, characterised by the presence of numerous small, white-yellow retinal lesions. FA belongs to a heterogenous group of so-called flecked retina syndromes. This disorder shows autosomal recessive inheritance and is caused mostly by mutations in the RDH5 gene. This gene encodes the enzyme that is a part of the visual cycle, the 11-cis retinol dehydrogenase. This study is a brief review of the literature on FA and a report of the first molecular evidence for RDH5 gene mutation in a Polish patient with this rare disorder. We present a novel pathogenic RDH5 gene mutation in a 16-year-old female patient with symptoms of night blindness. The patient underwent ophthalmological examinations, including colour vision testing, fundus photography, automated visual field testing, full-field electroretinography (ERG) and spectral optical coherent tomography (SOCT). The patient showed typical FA ERG records, the visual field was constricted and fundus examination revealed numerous characteristic, small, white-yellowish retinal lesions. DNA sequencing of the RDH5 gene coding sequence (exons 2-5) enabled the detection of the homozygous missense substitution c.524A > T (p.Tyr175Phe) in exon 3. This is the first report of RDH5 gene mutation that affects the invariant tyrosine, one of the most conserved amino acid residues in short-chain alcohol dehydrogenases/reductases (SDRs), crucial for these enzymes' activity. The location of this substitution, together with its predicted influence on the protein function, indicate that the p.Tyr175Phe mutation is the cause of FA in our patient. PMID:25820994

  3. Characterization of a spontaneous novel mutation in the NPC2 gene in a cat affected by Niemann Pick type C disease.

    PubMed

    Zampieri, Stefania; Bianchi, Ezio; Cantile, Carlo; Saleri, Roberta; Bembi, Bruno; Dardis, Andrea

    2014-01-01

    Niemann-Pick C disease (NPC) is an autosomal recessive lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids within the lysosomes due to mutation in NPC1 or NPC2 genes. A feline model of NPC carrying a mutation in NPC1 gene has been previously described. We have identified two kittens affected by NPC disease due to a mutation in NPC2 gene. They manifested with tremors at the age of 3 months, which progressed to dystonia and severe ataxia. At 6 months of age cat 2 was unable to stand without assistance and had bilaterally reduced menace response. It died at the age of 10 months. Post-mortem histological analysis of the brain showed the presence of neurons with cytoplasmic swelling and vacuoles, gliosis of the substantia nigra and degeneration of the white matter. Spheroids with accumulation of ubiquitinated aggregates were prominent in the cerebellar cortex. Purkinje cells were markedly reduced in number and they showed prominent intracytoplasmic storage. Scattered perivascular aggregates of lymphocytes and microglial cells proliferation were present in the thalamus and midbrain. Proliferation of Bergmann glia was also observed. In the liver, hepatocytes were swollen because of accumulation of small vacuoles and foamy Kupffer cells were also detected. Foamy macrophages were observed within the pulmonary interstitium and alveoli as well. At 9 months cat 1 was unable to walk, developed seizures and it was euthanized at 21 months. Filipin staining of cultured fibroblasts showed massive storage of unesterified cholesterol. Molecular analysis of NPC1 and NPC2 genes showed the presence of a homozygous intronic mutation (c.82+5G>A) in the NPC2 gene. The subsequent analysis of the mRNA showed that the mutation causes the retention of 105 bp in the mature mRNA, which leads to the in frame insertion of 35 amino acids between residues 28 and 29 of NPC2 protein (p.G28_S29ins35).

  4. Cellular interference in craniofrontonasal syndrome: males mosaic for mutations in the X-linked EFNB1 gene are more severely affected than true hemizygotes

    PubMed Central

    Twigg, Stephen R.F.; Babbs, Christian; van den Elzen, Marijke E.P.; Goriely, Anne; Taylor, Stephen; McGowan, Simon J.; Giannoulatou, Eleni; Lonie, Lorne; Ragoussis, Jiannis; Akha, Elham Sadighi; Knight, Samantha J.L.; Zechi-Ceide, Roseli M.; Hoogeboom, Jeannette A.M.; Pober, Barbara R.; Toriello, Helga V.; Wall, Steven A.; Rita Passos-Bueno, M.; Brunner, Han G.; Mathijssen, Irene M.J.; Wilkie, Andrew O.M.

    2013-01-01

    Craniofrontonasal syndrome (CFNS), an X-linked disorder caused by loss-of-function mutations of EFNB1, exhibits a paradoxical sex reversal in phenotypic severity: females characteristically have frontonasal dysplasia, craniosynostosis and additional minor malformations, but males are usually more mildly affected with hypertelorism as the only feature. X-inactivation is proposed to explain the more severe outcome in heterozygous females, as this leads to functional mosaicism for cells with differing expression of EPHRIN-B1, generating abnormal tissue boundaries—a process that cannot occur in hemizygous males. Apparently challenging this model, males occasionally present with a more severe female-like CFNS phenotype. We hypothesized that such individuals might be mosaic for EFNB1 mutations and investigated this possibility in multiple tissue samples from six sporadically presenting males. Using denaturing high performance liquid chromatography, massively parallel sequencing and multiplex-ligation-dependent probe amplification (MLPA) to increase sensitivity above standard dideoxy sequencing, we identified mosaic mutations of EFNB1 in all cases, comprising three missense changes, two gene deletions and a novel point mutation within the 5′ untranslated region (UTR). Quantification by Pyrosequencing and MLPA demonstrated levels of mutant cells between 15 and 69%. The 5′ UTR variant mutates the stop codon of a small upstream open reading frame that, using a dual-luciferase reporter construct, was demonstrated to exacerbate interference with translation of the wild-type protein. These results demonstrate a more severe outcome in mosaic than in constitutionally deficient males in an X-linked dominant disorder and provide further support for the cellular interference mechanism, normally related to X-inactivation in females. PMID:23335590

  5. Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants.

    PubMed

    Aroca, Ricardo; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; Paz, José Antonio; García-Mina, José María; Pozo, María José; López-Ráez, Juan Antonio

    2013-01-01

    Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress.

  6. Sinorhizobium meliloti requires a cobalamin-dependent ribonucleotide reductase for symbiosis with its plant host.

    PubMed

    Taga, Michiko E; Walker, Graham C

    2010-12-01

    Vitamin B(12) (cobalamin) is a critical cofactor for animals and protists, yet its biosynthesis is limited to prokaryotes. We previously showed that the symbiotic nitrogen-fixing alphaproteobacterium Sinorhizobium meliloti requires cobalamin to establish a symbiotic relationship with its plant host, Medicago sativa (alfalfa). Here, the specific requirement for cobalamin in the S. meliloti-alfalfa symbiosis was investigated. Of the three known cobalamin-dependent enzymes in S. meliloti, the methylmalonyl CoA mutase (BhbA) does not affect symbiosis, whereas disruption of the metH gene encoding the cobalamin-dependent methionine synthase causes a significant defect in symbiosis. Expression of the cobalamin-independent methionine synthase MetE alleviates this symbiotic defect, indicating that the requirement for methionine synthesis does not reflect a need for the cobalamin-dependent enzyme. To investigate the function of the cobalamin-dependent ribonucleotide reductase (RNR) encoded by nrdJ, S. meliloti was engineered to express an Escherichia coli cobalamin-independent (class Ia) RNR instead of nrdJ. This strain is severely defective in symbiosis. Electron micrographs show that these cells can penetrate alfalfa nodules but are unable to differentiate into nitrogen-fixing bacteroids and, instead, are lysed in the plant cytoplasm. Flow cytometry analysis indicates that these bacteria are largely unable to undergo endoreduplication. These phenotypes may be due either to the inactivation of the class Ia RNR by reactive oxygen species, inadequate oxygen availability in the nodule, or both. These results show that the critical role of the cobalamin-dependent RNR for survival of S. meliloti in its plant host can account for the considerable resources that S. meliloti dedicates to cobalamin biosynthesis.

  7. Symbiosis and the origin of eukaryotic motility

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Hinkle, G.

    1991-01-01

    Ongoing work to test the hypothesis of the origin of eukaryotic cell organelles by microbial symbioses is discussed. Because of the widespread acceptance of the serial endosymbiotic theory (SET) of the origin of plastids and mitochondria, the idea of the symbiotic origin of the centrioles and axonemes for spirochete bacteria motility symbiosis was tested. Intracellular microtubular systems are purported to derive from symbiotic associations between ancestral eukaryotic cells and motile bacteria. Four lines of approach to this problem are being pursued: (1) cloning the gene of a tubulin-like protein discovered in Spirocheata bajacaliforniesis; (2) seeking axoneme proteins in spirochets by antibody cross-reaction; (3) attempting to cultivate larger, free-living spirochetes; and (4) studying in detail spirochetes (e.g., Cristispira) symbiotic with marine animals. Other aspects of the investigation are presented.

  8. Brassinosteroids Regulate Root Growth, Development, and Symbiosis.

    PubMed

    Wei, Zhuoyun; Li, Jia

    2016-01-01

    Brassinosteroids (BRs) are natural plant hormones critical for growth and development. BR deficient or signaling mutants show significantly shortened root phenotypes. However, for a long time, it was thought that these phenotypes were solely caused by reduced cell elongation in the mutant roots. Functions of BRs in regulating root development have been largely neglected. Nonetheless, recent detailed analyses, revealed that BRs are not only involved in root cell elongation but are also involved in many aspects of root development, such as maintenance of meristem size, root hair formation, lateral root initiation, gravitropic response, mycorrhiza formation, and nodulation in legume species. In this review, current findings on the functions of BRs in mediating root growth, development, and symbiosis are discussed.

  9. A mutation in ribosomal protein L9 affects ribosomal hopping during translation of gene 60 from bacteriophage T4.

    PubMed Central

    Herbst, K L; Nichols, L M; Gesteland, R F; Weiss, R B

    1994-01-01

    Ribosomes hop over a 50-nt coding gap during translation of gene 60 mRNA from bacteriophage T4. This event occurs with near-unitary efficiency when gene 60-lacZ fusions are expressed in Escherichia coli. One of the components necessary for this hop is an RNA hairpin structure containing the 5' junction of the 50-nt coding gap. A mutant E. coli was isolated and found to significantly increase hopping when carrying gene 60-lacZ constructs with altered hairpins. The mutation, hop-1, changed Ser93 to Phe in rplI, the gene coding for ribosomal large-subunit protein L9. Ribosomal hopping on a synthetic sequence in the absence of a hairpin was also increased by this mutation. These data suggest that hop-1 may substitute for the function of the hairpin during ribosomal hopping. Images Fig. 1 Fig. 2 Fig. 4 PMID:7809071

  10. Defective oxidative phosphorylation in thyroid oncocytic carcinoma is associated with pathogenic mitochondrial DNA mutations affecting complexes I and III.

    PubMed

    Bonora, Elena; Porcelli, Anna Maria; Gasparre, Giuseppe; Biondi, Annalisa; Ghelli, Anna; Carelli, Valerio; Baracca, Alessandra; Tallini, Giovanni; Martinuzzi, Andrea; Lenaz, Giorgio; Rugolo, Michela; Romeo, Giovanni

    2006-06-15

    Oncocytic tumors are characterized by cells with an aberrant accumulation of mitochondria. To assess mitochondrial function in neoplastic oncocytic cells, we studied the thyroid oncocytic cell line XTC.UC1 and compared it with other thyroid non-oncocytic cell lines. Only XTC.UC1 cells were unable to survive in galactose, a condition forcing cells to rely solely on mitochondria for energy production. The rate of respiration and mitochondrial ATP synthesis driven by complex I substrates was severely reduced in XTC.UC1 cells. Furthermore, the enzymatic activity of complexes I and III was dramatically decreased in these cells compared with controls, in conjunction with a strongly enhanced production of reactive oxygen species. Osteosarcoma-derived transmitochondrial cell hybrids (cybrids) carrying XTC.UC1 mitochondrial DNA (mtDNA) were generated to discriminate whether the energetic failure depended on mitochondrial or nuclear DNA mutations. In galactose medium, XTC.UC1 cybrid clones showed reduced viability and ATP content, similarly to the parental XTC.UC1, clearly pointing to the existence of mtDNA alterations. Sequencing of XTC.UC1 mtDNA identified a frameshift mutation in ND1 and a nonconservative substitution in cytochrome b, two mutations with a clear pathogenic potential. In conclusion, this is the first demonstration that mitochondrial dysfunction of XTC.UC1 is due to a combined complex I/III defect associated with mtDNA mutations, as proven by the transfer of the defective energetic phenotype with the mitochondrial genome into the cybrids.

  11. Mutations Affecting Potassium Import Restore the Viability of the Escherichia coli DNA Polymerase III holD Mutant

    PubMed Central

    Durand, Adeline

    2016-01-01

    Mutants lacking the ψ (HolD) subunit of the Escherichia coli DNA Polymerase III holoenzyme (Pol III HE) have poor viability, but a residual growth allows the isolation of spontaneous suppressor mutations that restore ΔholD mutant viability. Here we describe the isolation and characterization of two suppressor mutations in the trkA and trkE genes, involved in the main E. coli potassium import system. Viability of ΔholD trk mutants is abolished on media with low or high K+ concentrations, where alternative K+ import systems are activated, and is restored on low K+ concentrations by the inactivation of the alternative Kdp system. These findings show that the ΔholD mutant is rescued by a decrease in K+ import. The effect of trk inactivation is additive with the previously identified ΔholD suppressor mutation lexAind that blocks the SOS response indicating an SOS-independent mechanism of suppression. Accordingly, although lagging-strand synthesis is still perturbed in holD trkA mutants, the trkA mutation allows HolD-less Pol III HE to resist increased levels of the SOS-induced bypass polymerase DinB. trk inactivation is also partially additive with an ssb gene duplication, proposed to stabilize HolD-less Pol III HE by a modification of the single-stranded DNA binding protein (SSB) binding mode. We propose that lowering the intracellular K+ concentration stabilizes HolD-less Pol III HE on DNA by increasing electrostatic interactions between Pol III HE subunits, or between Pol III and DNA, directly or through a modification of the SSB binding mode; these three modes of action are not exclusive and could be additive. To our knowledge, the holD mutant provides the first example of an essential protein-DNA interaction that strongly depends on K+ import in vivo. PMID:27280472

  12. A Mutation in an Hsp90 Gene Affects the Sexual Cycle and Suppresses Vegetative Incompatibility in the Fungus Podospora Anserina

    PubMed Central

    Loubradou, G.; Begueret, J.; Turcq, B.

    1997-01-01

    Vegetative incompatibility is widespread in fungi but its molecular mechanism and biological function are still poorly understood. A way to study vegetative incompatibility is to investigate the function of genes whose mutations suppress this phenomenon. In Podospora anserina, these genes are known as mod genes. In addition to suppressing vegetative incompatibility, mod mutations cause some developmental defects. This suggests that the molecular mechanisms of vegetative incompatibility and development pathways are interconnected. The mod-E1 mutation was isolated as a suppressor of the developmental defects of the mod-D2 strain. We show here that mod-E1 also partially suppresses vegetative incompatibility, strengthening the link between development and vegetative incompatibility. mod-E1 is the first suppressor of vegetative incompatibility characterized at the molecular level. It encodes a member of the Hsp90 family, suggesting that development and vegetative incompatibility use common steps of a signal transduction pathway. The involvement of mod-E in the sexual cycle has also been further investigated. PMID:9335595

  13. A Genetic Screen for Mutations Affecting Cell Division in the Arabidopsis thaliana Embryo Identifies Seven Loci Required for Cytokinesis

    PubMed Central

    Gillmor, C. Stewart; Roeder, Adrienne H. K.; Sieber, Patrick; Somerville, Chris; Lukowitz, Wolfgang

    2016-01-01

    Cytokinesis in plants involves the formation of unique cellular structures such as the phragmoplast and the cell plate, both of which are required to divide the cell after nuclear division. In order to isolate genes that are involved in de novo cell wall formation, we performed a large-scale, microscope-based screen for Arabidopsis mutants that severely impair cytokinesis in the embryo. We recovered 35 mutations that form abnormally enlarged cells with multiple, often polyploid nuclei and incomplete cell walls. These mutants represent seven genes, four of which have previously been implicated in phragmoplast or cell plate function. Mutations in two loci show strongly reduced transmission through the haploid gametophytic generation. Molecular cloning of both corresponding genes reveals that one is represented by hypomorphic alleles of the kinesin-5 gene RADIALLY SWOLLEN 7 (homologous to tobacco kinesin-related protein TKRP125), and that the other gene corresponds to the Arabidopsis FUSED ortholog TWO-IN-ONE (originally identified based on its function in pollen development). No mutations that completely abolish the formation of cross walls in diploid cells were found. Our results support the idea that cytokinesis in the diploid and haploid generations involve similar mechanisms. PMID:26745275

  14. Mutation of the phospholipase C-gamma1-binding site of LAT affects both positive and negative thymocyte selection.

    PubMed

    Sommers, Connie L; Lee, Jan; Steiner, Kevin L; Gurson, Jordan M; Depersis, Corinne L; El-Khoury, Dalal; Fuller, Claudette L; Shores, Elizabeth W; Love, Paul E; Samelson, Lawrence E

    2005-04-01

    Linker for activation of T cells (LAT) is a scaffolding adaptor protein that is critical for T cell development and function. A mutation of LAT (Y136F) that disrupts phospholipase C-gamma1 activation and subsequent calcium influx causes a partial block in T cell development and leads to a severe lymphoproliferative disease in homozygous knock-in mice. One possible contribution to the fatal disease of LAT Y136F knock-in mice could be from autoreactive T cells generated in these mice because of altered thymocyte selection. To examine the impact of the LAT Y136F mutation on thymocyte positive and negative selection, we bred this mutation onto the HY T cell receptor (TCR) transgenic, recombination activating gene-2 knockout background. Female mice with this genotype showed a severe defect in positive selection, whereas male mice exhibited a phenotype resembling positive selection (i.e., development and survival of CD8(hi) HY TCR-specific T cells) instead of negative selection. These results support the hypothesis that in non-TCR transgenic, LAT Y136F knock-in mice, altered thymocyte selection leads to the survival and proliferation of autoreactive T cells that would otherwise be negatively selected in the thymus.

  15. Epilepsy-causing mutations in Kv7.2 C-terminus affect binding and functional modulation by calmodulin.

    PubMed

    Ambrosino, Paolo; Alaimo, Alessandro; Bartollino, Silvia; Manocchio, Laura; De Maria, Michela; Mosca, Ilaria; Gomis-Perez, Carolina; Alberdi, Araitz; Scambia, Giovanni; Lesca, Gaetan; Villarroel, Alvaro; Taglialatela, Maurizio; Soldovieri, Maria Virginia

    2015-09-01

    Mutations in the KCNQ2 gene, encoding for voltage-gated Kv7.2K(+) channel subunits, are responsible for early-onset epileptic diseases with widely-diverging phenotypic presentation, ranging from Benign Familial Neonatal Seizures (BFNS) to epileptic encephalopathy. In the present study, Kv7.2 BFNS-causing mutations (W344R, L351F, L351V, Y362C, and R553Q) have been investigated for their ability to interfere with calmodulin (CaM) binding and CaM-induced channel regulation. To this aim, semi-quantitative (Far-Western blotting) and quantitative (Surface Plasmon Resonance and dansylated CaM fluorescence) biochemical assays have been performed to investigate the interaction of CaM with wild-type or mutant Kv7.2 C-terminal fragments encompassing the CaM-binding domain; in parallel, mutation-induced changes in CaM-dependent Kv7.2 or Kv7.2/Kv7.3 current regulation were investigated by patch-clamp recordings in Chinese Hamster Ovary (CHO) cells co-expressing Kv7.2 or Kv7.2/Kv7.3 channels and CaM or CaM1234 (a CaM isoform unable to bind Ca(2+)). The results obtained suggest that each BFNS-causing mutation prompts specific biochemical and/or functional consequences; these range from slight alterations in CaM affinity which did not translate into functional changes (L351V), to a significant reduction in the affinity and functional modulation by CaM (L351F, Y362C or R553Q), to a complete functional loss without significant alteration in CaM affinity (W344R). CaM overexpression increased Kv7.2 and Kv7.2/Kv7.3 current levels, and partially (R553Q) or fully (L351F) restored normal channel function, providing a rationale pathogenetic mechanism for mutation-induced channel dysfunction in BFNS, and highlighting the potentiation of CaM-dependent Kv7.2 modulation as a potential therapeutic approach for Kv7.2-related epilepsies.

  16. Identification of Genetic Loci Affecting the Severity of Symptoms of Hirschsprung Disease in Rats Carrying Ednrbsl Mutations by Quantitative Trait Locus Analysis

    PubMed Central

    Torigoe, Daisuke; Lei, Chuzhao; Lan, Xianyong; Chen, Hong; Sasaki, Nobuya; Wang, Jinxi; Agui, Takashi

    2015-01-01

    Hirschsprung’s disease (HSCR) is a congenital disease in neonates characterized by the absence of the enteric ganglia in a variable length of the distal colon. This disease results from multiple genetic interactions that modulate the ability of enteric neural crest cells to populate developing gut. We previously reported that three rat strains with different backgrounds (susceptible AGH-Ednrbsl/sl, resistant F344-Ednrbsl/sl, and LEH-Ednrbsl/sl) but the same null mutation of Ednrb show varying severity degrees of aganglionosis. This finding suggests that strain-specific genetic factors affect the severity of HSCR. Consistent with this finding, a quantitative trait locus (QTL) for the severity of HSCR on chromosome (Chr) 2 was identified using an F2 intercross between AGH and F344 strains. In the present study, we performed QTL analysis using an F2 intercross between the susceptible AGH and resistant LEH strains to identify the modifier/resistant loci for HSCR in Ednrb-deficient rats. A significant locus affecting the severity of HSCR was also detected within the Chr 2 region. These findings strongly suggest that a modifier gene of aganglionosis exists on Chr 2. In addition, two potentially causative SNPs (or mutations) were detected upstream of a known HSCR susceptibility gene, Gdnf. These SNPs were possibly responsible for the varied length of gut affected by aganglionosis. PMID:25790447

  17. Mutations in the alpha-amanitin conserved domain of the largest subunit of yeast RNA polymerase III affect pausing, RNA cleavage and transcriptional transitions.

    PubMed Central

    Thuillier, V; Brun, I; Sentenac, A; Werner, M

    1996-01-01

    The alpha-amanitin domain or domain f of the largest subunit of RNA polymerases is one of the most conserved of these enzymes. We have found that the C-terminal part of domain f can be swapped between yeast RNA polymerase II and III. An extensive mutagenesis of domain f of C160, the largest subunit of RNA polymerase III, was carried out to better define its role and understand the mechanism through which C160 participates in transcription. One mutant enzyme, C160-270, showed much reduced transcription of a non-specific template at low DNA concentrations. Abortive synthesis of trinucleotides in a dinucleotide-primed reaction proceeded at roughly wild-type levels, indicating that the mutation did not affect the formation of the first phosphodiester bond, but rather the transition from abortive initiation to processive elongation. In specific transcription assays, on the SUP4 tRNA gene, pausing was extended but the rate of RNA elongation between pause sites was not affected. Finally, the rate of cleavage of nascent RNA transcripts by halted mutant RNA polymerase was increased approximately 10-fold. We propose that the domain f mutation affects the transition between two transcriptional modes, one being adopted during abortive transcription and at pause sites, the other during elongation between pause sites. Images PMID:8599945

  18. Study of cnidarian-algal symbiosis in the "omics" age.

    PubMed

    Meyer, Eli; Weis, Virginia M

    2012-08-01

    The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium. PMID:22983032

  19. DNA Microarray and Gene Ontology Enrichment Analysis Reveals That a Mutation in opsX Affects Virulence and Chemotaxis in Xanthomonas oryzae pv. oryzae

    PubMed Central

    Kim, Hong-Il; Park, Young-Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) in rice (Oryza sativa L.). In this study, we investigated the effect of a mutation in opsX (XOO1056), which encodes a saccharide biosynthesis regulatory protein, on the virulence and bacterial chemotaxis of Xoo. We performed DNA microarray analysis, which showed that 63 of 2,678 genes, including genes related to bacterial motility (flagellar and chemotaxis proteins) were significantly downregulated (<−2 log2 fold changes) by the mutation in opsX. Indeed, motility assays showed that the mutant strain was nonmotile on semisolid agar swarm plates. In addition, a mutant strain (opsX::Tn5) showed decreased virulence against the susceptible rice cultivar, IR24. Quantitative real-time RT-PCR reaction was performed to confirm the expression levels of these genes, including those related to flagella and chemotaxis, in the opsX mutant. Our findings revealed that mutation of opsX affects both virulence and bacterial motility. These results will help to improve our understanding of Xoo and provide insight into Xoo-rice interactions. PMID:27298594

  20. Lenz-Majewski mutations in PTDSS1 affect phosphatidylinositol 4-phosphate metabolism at ER-PM and ER-Golgi junctions.

    PubMed

    Sohn, Mira; Ivanova, Pavlina; Brown, H Alex; Toth, Daniel J; Varnai, Peter; Kim, Yeun Ju; Balla, Tamas

    2016-04-19

    Lenz-Majewski syndrome (LMS) is a rare disease characterized by complex craniofacial, dental, cutaneous, and limb abnormalities combined with intellectual disability. Mutations in thePTDSS1gene coding one of the phosphatidylserine (PS) synthase enzymes, PSS1, were described as causative in LMS patients. Such mutations render PSS1 insensitive to feedback inhibition by PS levels. Here we show that expression of mutant PSS1 enzymes decreased phosphatidylinositol 4-phosphate (PI4P) levels both in the Golgi and the plasma membrane (PM) by activating the Sac1 phosphatase and altered PI4P cycling at the PM. Conversely, inhibitors of PI4KA, the enzyme that makes PI4P in the PM, blocked PS synthesis and reduced PS levels by 50% in normal cells. However, mutant PSS1 enzymes alleviated the PI4P dependence of PS synthesis. Oxysterol-binding protein-related protein 8, which was recently identified as a PI4P-PS exchanger between the ER and PM, showed PI4P-dependent membrane association that was significantly decreased by expression of PSS1 mutant enzymes. Our studies reveal that PS synthesis is tightly coupled to PI4P-dependent PS transport from the ER. Consequently, PSS1 mutations not only affect cellular PS levels and distribution but also lead to a more complex imbalance in lipid homeostasis by disturbing PI4P metabolism. PMID:27044099

  1. The RetC620R Mutation Affects Renal and Enteric Development in a Mouse Model of Hirschsprung’s Disease

    PubMed Central

    Carniti, Cristiana; Belluco, Sara; Riccardi, Elena; Cranston, Aaron N.; Mondellini, Piera; Ponder, Bruce A.J.; Scanziani, Eugenio; Pierotti, Marco A.; Bongarzone, Italia

    2006-01-01

    In rare families RET tyrosine kinase receptor substitutions located in exon 10 (especially at positions 609, 618, and 620) can concomitantly cause the MEN 2A (multiple endocrine neoplasia type 2A) or FMTC (familial medullary thyroid carcinoma) cancer syndromes, and Hirschsprung’s disease (HSCR). No animal model mimicking the co-existence of the MEN 2 pathology and HSCR is available, and the association of these activating mutations with a developmental defect still represents an unresolved problem. The aim of this work was to investigate the significance of the RETC620R substitution in the pathogenesis of both gain- and loss-of-function RET-associated diseases. We report the generation of a line of mice carrying the C620R mutation in the Ret gene. Although RetC620R homozygotes display severe defects in kidney organogenesis and enteric nervous system development leading to perinatal lethality. RetC620R heterozygotes recapitulate features characteristic of HSCR including hypoganglionosis of the gastrointestinal tract. Surprisingly, heterozygotes do not show any defects in the thyroid that might be attributable to a gain-of-function mutation. The RetC620R allele is responsible for HSCR and affects the development of kidneys and the enteric nervous system (ENS). These mice represent an interesting model for studying new therapeutic approaches for the treatment of HSCR disease. PMID:16565500

  2. Prenatal manifestation and management of a mother and child affected by spondyloperipheral dysplasia with a C-propeptide mutation in COL2A1: case report

    PubMed Central

    2011-01-01

    It is not unusual for patients with "rare" conditions, such as skeletal dysplasias, to remain undiagnosed until adulthood. In such cases, a pregnancy may unexpectedly reveal hidden problems and special needs. A 28 year old primigravida was referred to us at 17 weeks for counselling with an undiagnosed skeletal dysplasia with specific skeletal anomalies suggesting the collagen 2 disorder, spondyloperipheral dysplasia (SPD; MIM 156550). She was counselled about the probability of dominant inheritance and was offered a prenatal diagnosis by sonography. US examination at 17, 18 and 20 weeks revealed fetal macrocephaly, a narrow thorax, and shortening and bowing of long bones. The parents elected to continue the pregnancy. At birth the baby showed severe respiratory distress for four weeks which then resolved. Mutation analysis of both mother and child revealed a hitherto undescribed heterozygous nonsense mutation in the C-propeptide coding region of COL2A1 confirming the diagnosis of SPD while reinforcing the genotype-phenotype correlations between C-propeptide COL2A1 mutations and the SPD-Torrance spectrum. This case demonstrates the importance of a correct diagnosis even in adulthood, enabling individuals affected by rare conditions to be made aware about recurrence and pregnancy-associated risks, and potential complications in the newborn. PMID:21356074

  3. Lenz-Majewski mutations in PTDSS1 affect phosphatidylinositol 4-phosphate metabolism at ER-PM and ER-Golgi junctions

    PubMed Central

    Sohn, Mira; Ivanova, Pavlina; Brown, H. Alex; Varnai, Peter; Kim, Yeun Ju; Balla, Tamas

    2016-01-01

    Lenz-Majewski syndrome (LMS) is a rare disease characterized by complex craniofacial, dental, cutaneous, and limb abnormalities combined with intellectual disability. Mutations in the PTDSS1 gene coding one of the phosphatidylserine (PS) synthase enzymes, PSS1, were described as causative in LMS patients. Such mutations render PSS1 insensitive to feedback inhibition by PS levels. Here we show that expression of mutant PSS1 enzymes decreased phosphatidylinositol 4-phosphate (PI4P) levels both in the Golgi and the plasma membrane (PM) by activating the Sac1 phosphatase and altered PI4P cycling at the PM. Conversely, inhibitors of PI4KA, the enzyme that makes PI4P in the PM, blocked PS synthesis and reduced PS levels by 50% in normal cells. However, mutant PSS1 enzymes alleviated the PI4P dependence of PS synthesis. Oxysterol-binding protein–related protein 8, which was recently identified as a PI4P-PS exchanger between the ER and PM, showed PI4P-dependent membrane association that was significantly decreased by expression of PSS1 mutant enzymes. Our studies reveal that PS synthesis is tightly coupled to PI4P-dependent PS transport from the ER. Consequently, PSS1 mutations not only affect cellular PS levels and distribution but also lead to a more complex imbalance in lipid homeostasis by disturbing PI4P metabolism. PMID:27044099

  4. Lenz-Majewski mutations in PTDSS1 affect phosphatidylinositol 4-phosphate metabolism at ER-PM and ER-Golgi junctions.

    PubMed

    Sohn, Mira; Ivanova, Pavlina; Brown, H Alex; Toth, Daniel J; Varnai, Peter; Kim, Yeun Ju; Balla, Tamas

    2016-04-19

    Lenz-Majewski syndrome (LMS) is a rare disease characterized by complex craniofacial, dental, cutaneous, and limb abnormalities combined with intellectual disability. Mutations in thePTDSS1gene coding one of the phosphatidylserine (PS) synthase enzymes, PSS1, were described as causative in LMS patients. Such mutations render PSS1 insensitive to feedback inhibition by PS levels. Here we show that expression of mutant PSS1 enzymes decreased phosphatidylinositol 4-phosphate (PI4P) levels both in the Golgi and the plasma membrane (PM) by activating the Sac1 phosphatase and altered PI4P cycling at the PM. Conversely, inhibitors of PI4KA, the enzyme that makes PI4P in the PM, blocked PS synthesis and reduced PS levels by 50% in normal cells. However, mutant PSS1 enzymes alleviated the PI4P dependence of PS synthesis. Oxysterol-binding protein-related protein 8, which was recently identified as a PI4P-PS exchanger between the ER and PM, showed PI4P-dependent membrane association that was significantly decreased by expression of PSS1 mutant enzymes. Our studies reveal that PS synthesis is tightly coupled to PI4P-dependent PS transport from the ER. Consequently, PSS1 mutations not only affect cellular PS levels and distribution but also lead to a more complex imbalance in lipid homeostasis by disturbing PI4P metabolism.

  5. DNA Microarray and Gene Ontology Enrichment Analysis Reveals That a Mutation in opsX Affects Virulence and Chemotaxis in Xanthomonas oryzae pv. oryzae.

    PubMed

    Kim, Hong-Il; Park, Young-Jin

    2016-06-01

    Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) in rice (Oryza sativa L.). In this study, we investigated the effect of a mutation in opsX (XOO1056), which encodes a saccharide biosynthesis regulatory protein, on the virulence and bacterial chemotaxis of Xoo. We performed DNA microarray analysis, which showed that 63 of 2,678 genes, including genes related to bacterial motility (flagellar and chemotaxis proteins) were significantly downregulated (<-2 log2 fold changes) by the mutation in opsX. Indeed, motility assays showed that the mutant strain was nonmotile on semisolid agar swarm plates. In addition, a mutant strain (opsX::Tn5) showed decreased virulence against the susceptible rice cultivar, IR24. Quantitative real-time RT-PCR reaction was performed to confirm the expression levels of these genes, including those related to flagella and chemotaxis, in the opsX mutant. Our findings revealed that mutation of opsX affects both virulence and bacterial motility. These results will help to improve our understanding of Xoo and provide insight into Xoo-rice interactions.

  6. [Heterozygosity for Mutations Affecting Coat Pigmentation in the American Mink (Neovison vison) Enhances Structural Stability of Adrenal Cortex under Stress Conditions].

    PubMed

    Trapezov, O V; Luzenko, N D; Trapezova, L I

    2016-04-01

    The results of the study of the effects of heterozygosity for mutations affecting coat pigmentation on the response to the environmental stress caused by extreme feeding conditions are provided. The animals with the following genotypes were taken into the study: homozygotes standard (+/+), hedlund white (h/h), and aleutian (a/a) and heterozygotes hedlund white (h/+) and aleutian (a/+). The animals homozygous for the aleutian mutation (a/a) showed a statistically lower growth rate than the animals of other genotypes both in the ontrol and in the experiment (p < 0.05). Under the control conditions, the animals homozygous forboth the wild type standard allele (+/+) and the mutant hedlund white (h/h) and aleutian (a/a) alleles showed the evident tendency for the zona fasciculata and zona reticularis of the adrenal cortex broadening compared to the experimental conditions. At the same time, in the animals heterozygous for the hedlund white (h/+) and the aleutian (a/+) mutations, a clear tendency for increasing size of the zona fasciculata and zona reticularis under the experimental conditions was observed. In the heterozygous animals, although we observed single destructive changes in the adrenal cortex under stress conditions, they were much less profound than in the homozygous ones. This may be related to the broader range of morphological adaptation in the heterozygotes, which gives them the possibility of more significant enlargement of the secreting zone to provide for its adequate functioning. PMID:27529984

  7. [Heterozygosity for Mutations Affecting Coat Pigmentation in the American Mink (Neovison vison) Enhances Structural Stability of Adrenal Cortex under Stress Conditions].

    PubMed

    Trapezov, O V; Luzenko, N D; Trapezova, L I

    2016-04-01

    The results of the study of the effects of heterozygosity for mutations affecting coat pigmentation on the response to the environmental stress caused by extreme feeding conditions are provided. The animals with the following genotypes were taken into the study: homozygotes standard (+/+), hedlund white (h/h), and aleutian (a/a) and heterozygotes hedlund white (h/+) and aleutian (a/+). The animals homozygous for the aleutian mutation (a/a) showed a statistically lower growth rate than the animals of other genotypes both in the ontrol and in the experiment (p < 0.05). Under the control conditions, the animals homozygous forboth the wild type standard allele (+/+) and the mutant hedlund white (h/h) and aleutian (a/a) alleles showed the evident tendency for the zona fasciculata and zona reticularis of the adrenal cortex broadening compared to the experimental conditions. At the same time, in the animals heterozygous for the hedlund white (h/+) and the aleutian (a/+) mutations, a clear tendency for increasing size of the zona fasciculata and zona reticularis under the experimental conditions was observed. In the heterozygous animals, although we observed single destructive changes in the adrenal cortex under stress conditions, they were much less profound than in the homozygous ones. This may be related to the broader range of morphological adaptation in the heterozygotes, which gives them the possibility of more significant enlargement of the secreting zone to provide for its adequate functioning.

  8. Iron: an essential micronutrient for the legume-rhizobium symbiosis

    PubMed Central

    Brear, Ella M.; Day, David A.; Smith, Penelope M. C.

    2013-01-01

    Legumes, which develop a symbiosis with nitrogen-fixing bacteria, have an increased demand for iron. Iron is required for the synthesis of iron-containing proteins in the host, including the highly abundant leghemoglobin, and in bacteroids for nitrogenase and cytochromes of the electron transport chain. Deficiencies in iron can affect initiation and development of the nodule. Within root cells, iron is chelated with organic acids such as citrate and nicotianamine and distributed to other parts of the plant. Transport to the nitrogen-fixing bacteroids in infected cells of nodules is more complicated. Formation of the symbiosis results in bacteroids internalized within root cortical cells of the legume where they are surrounded by a plant-derived membrane termed the symbiosome membrane (SM). This membrane forms an interface that regulates nutrient supply to the bacteroid. Consequently, iron must cross this membrane before being supplied to the bacteroid. Iron is transported across the SM as both ferric and ferrous iron. However, uptake of Fe(II) by both the symbiosome and bacteroid is faster than Fe(III) uptake. Members of more than one protein family may be responsible for Fe(II) transport across the SM. The only Fe(II) transporter in nodules characterized to date is GmDMT1 (Glycine max divalent metal transporter 1), which is located on the SM in soybean. Like the root plasma membrane, the SM has ferric iron reductase activity. The protein responsible has not been identified but is predicted to reduce ferric iron accumulated in the symbiosome space prior to uptake by the bacteroid. With the recent publication of a number of legume genomes including Medicago truncatula and G. max, a large number of additional candidate transport proteins have been identified. Members of the NRAMP (natural resistance-associated macrophage protein), YSL (yellow stripe-like), VIT (vacuolar iron transporter), and ZIP (Zrt-, Irt-like protein) transport families show enhanced expression in

  9. Tmc1 Point Mutation Affects Ca2+ Sensitivity and Block by Dihydrostreptomycin of the Mechanoelectrical Transducer Current of Mouse Outer Hair Cells

    PubMed Central

    Corns, Laura F.; Johnson, Stuart L.; Kros, Corné J.

    2016-01-01

    transmembrane channel-like protein isoform 1 (TMC1) channels in the mammalian cochlea. Using a mutant mouse model (Beethoven) for progressive hearing loss in humans (DFNA36), which harbors a point mutation in the Tmc1 gene, we show that this mutation affects the MET channel pore, reducing its Ca2+ permeability and its affinity for the permeant blocker dihydrostreptomycin. A number of phenomena that we ascribe to Ca2+-dependent adaptation appear stronger, in compensation for the reduced Ca2+ entry. PMID:26758827

  10. Mutation in the primer binding site of the type 1 human immunodeficiency virus genome affects virus production and infectivity.

    PubMed Central

    Nagashunmugam, T; Velpandi, A; Goldsmith, C S; Zaki, S R; Kalyanaraman, V S; Srinivasan, A

    1992-01-01

    In an effort to understand the contribution of the primer-binding site (PBS) region to human immunodeficiency virus (HIV) replication, we have constructed a mutant HIV proviral DNA with an alteration in the 5' end of the PBS. The PBS mutant proviral DNA was characterized by transfection of the viral DNA into CD4+ and non-CD4+ target cells. The results indicate that mutation in the PBS reduced the level of viral particles released into the medium of transfected cells in comparison to wild-type proviral DNA. The viral particles were noninfectious upon transmission to established CD4+ cell lines and phytohemagglutinin-stimulated peripheral blood lymphocytes. Electron microscopic analysis of the transfected cells revealed no abnormalities in the structure of the virion directed by the mutant proviral DNA. Also, the protein and RNA contents of the mutant virions were similar to the wild type. The quantitation of intracellular viral structural protein in the transfected cells, however, indicated that the PBS mutation may have an effect on the assembly of viral particles in addition to completely abolishing reverse transcription of viral RNA into DNA. These results provide evidence that the PBS region of the viral genome has multiple functions in HIV-1 replication. Images PMID:1373895

  11. Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces

    NASA Technical Reports Server (NTRS)

    Rutherford, R.; Gallois, P.; Masson, P. H.

    1998-01-01

    Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type. Genetic and pharmacological experiments argue that the compressed root wave phenotypes of trp5-2wvc1, trp2-1 and trp3-1 seedlings are not due to reduced IAA biosynthetic potential, but rather to a deficiency in L-tryptophan (L-Trp), or in a L-Trp derivative. Although the roots of 7-day-old seedlings possess higher concentrations of free L-Trp than the shoot as a whole, trp5-2wvc1 mutants show no detectable alteration in L-Trp levels in either tissue type, suggesting that a very localized shortage of L-Trp, or of a L-Trp-derived compound, is responsible for the observed phenotype.

  12. Cyclophilin and the regulation of symbiosis in Aiptasia pallida.

    PubMed

    Perez, S; Weis, V

    2008-08-01

    The sea anemone Aiptasia pallida, symbiotic with intracellular dinoflagellates, expresses a peptydyl-prolyl cis-trans isomerase (PPIase) belonging to the conserved family of cytosolic cyclophilins (ApCypA). Protein extracts from A. pallida exhibited PPIase activity. Given the high degree of conservation of ApCypA and its known function in the cellular stress response, we hypothesized that it plays a similar role in the cnidarian-dinoflagellate symbiosis. To explore its role, we inhibited the activity of cyclophilin with cyclosporin A (CsA). CsA effectively inhibited the PPIase activity of protein extracts from symbiotic A. pallida. CsA also induced the dose-dependent release of symbiotic algae from host tissues (bleaching). Laser scanning confocal microscopy using superoxide and nitric oxide-sensitive fluorescent dyes on live specimens of A. pallida revealed that CsA strongly induced the production of these known mediators of bleaching. We tested whether the CsA-sensitive isomerase activity is important for maintaining the activity of the antioxidant enzyme superoxide dismutase (SOD). SOD activity of protein extracts was not affected by pre-incubation with CsA in vitro. PMID:18723638

  13. Mutation accumulation and fitness in mutator subpopulations of Escherichia coli.

    PubMed

    Maharjan, Ram P; Liu, Bin; Li, Yang; Reeves, Peter R; Wang, Lei; Ferenci, Thomas

    2013-02-23

    Bacterial populations in clinical and laboratory settings contain a significant proportion of mutants with elevated mutation rates (mutators). Mutators have a particular advantage when multiple beneficial mutations are needed for fitness, as in antibiotic resistance. Nevertheless, high mutation rates potentially lead to increasing numbers of deleterious mutations and subsequently to the decreased fitness of mutators. To test how fitness changed with mutation accumulation, genome sequencing and fitness assays of nine Escherichia coli mutY mutators were undertaken in an evolving chemostat population at three time points. Unexpectedly, the fitness in members of the mutator subpopulation became constant despite a growing number of mutations over time. To test if the accumulated mutations affected fitness, we replaced each of the known beneficial mutations with wild-type alleles in a mutator isolate. We found that the other 25 accumulated mutations were not deleterious. Our results suggest that isolates with deleterious mutations are eliminated by competition in a continuous culture, leaving mutators with mostly neutral mutations. Interestingly, the mutator-non-mutator balance in the population reversed after the fitness plateau of mutators was reached, suggesting that the mutator-non-mutator ratio in populations has more to do with competition between members of the population than the accumulation of deleterious mutations.

  14. Consequences of symbiosis for food web dynamics.

    PubMed

    Kooi, B W; Kuijper, L D J; Kooijman, S A L M

    2004-09-01

    Basic Lotka-Volterra type models in which mutualism (a type of symbiosis where the two populations benefit both) is taken into account, may give unbounded solutions. We exclude such behaviour using explicit mass balances and study the consequences of symbiosis for the long-term dynamic behaviour of a three species system, two prey and one predator species in the chemostat. We compose a theoretical food web where a predator feeds on two prey species that have a symbiotic relationships. In addition to a species-specific resource, the two prey populations consume the products of the partner population as well. In turn, a common predator forages on these prey populations. The temporal change in the biomass and the nutrient densities in the reactor is described by ordinary differential equations (ODE). Since products are recycled, the dynamics of these abiotic materials must be taken into account as well, and they are described by odes in a similar way as the abiotic nutrients. We use numerical bifurcation analysis to assess the long-term dynamic behaviour for varying degrees of symbiosis. Attractors can be equilibria, limit cycles and chaotic attractors depending on the control parameters of the chemostat reactor. These control parameters that can be experimentally manipulated are the nutrient density of the inflow medium and the dilution rate. Bifurcation diagrams for the three species web with a facultative symbiotic association between the two prey populations, are similar to that of a bi-trophic food chain; nutrient enrichment leads to oscillatory behaviour. Predation combined with obligatory symbiotic prey-interactions has a stabilizing effect, that is, there is stable coexistence in a larger part of the parameter space than for a bi-trophic food chain. However, combined with a large growth rate of the predator, the food web can persist only in a relatively small region of the parameter space. Then, two zero-pair bifurcation points are the organizing centers. In

  15. Academia–Industry Symbiosis in Organic Chemistry

    PubMed Central

    2015-01-01

    Conspectus Collaboration between academia and industry is a growing phenomenon within the chemistry community. These sectors have long held strong ties since academia traditionally trains the future scientists of the corporate world, but the recent drastic decrease of public funding is motivating the academic world to seek more private grants. This concept of industrial “sponsoring” is not new, and in the past, some companies granted substantial amounts of money per annum to various academic institutions in exchange for prime access to all their scientific discoveries and inventions. However, academic and industrial interests were not always aligned, and therefore the investment has become increasingly difficult to justify from industry’s point of view. With fluctuating macroeconomic factors, this type of unrestricted grant has become more rare and has been largely replaced by smaller and more focused partnerships. In our view, forging a partnership with industry can be a golden opportunity for both parties and can represent a true symbiosis. This type of project-specific collaboration is engendered by industry’s desire to access very specific academic expertise that is required for the development of new technologies at the forefront of science. Since financial pressures do not allow companies to spend the time to acquire this expertise and even less to explore fundamental research, partnering with an academic laboratory whose research is related to the problem gives them a viable alternative. From an academic standpoint, it represents the perfect occasion to apply “pure science” research concepts to solve problems that benefit humanity. Moreover, it offers a unique opportunity for students to face challenges from the “real world” at an early stage of their career. Although not every problem in industry can be solved by research developments in academia, we argue that there is significant scientific overlap between these two seemingly disparate

  16. Academia-industry symbiosis in organic chemistry.

    PubMed

    Michaudel, Quentin; Ishihara, Yoshihiro; Baran, Phil S

    2015-03-17

    Collaboration between academia and industry is a growing phenomenon within the chemistry community. These sectors have long held strong ties since academia traditionally trains the future scientists of the corporate world, but the recent drastic decrease of public funding is motivating the academic world to seek more private grants. This concept of industrial "sponsoring" is not new, and in the past, some companies granted substantial amounts of money per annum to various academic institutions in exchange for prime access to all their scientific discoveries and inventions. However, academic and industrial interests were not always aligned, and therefore the investment has become increasingly difficult to justify from industry's point of view. With fluctuating macroeconomic factors, this type of unrestricted grant has become more rare and has been largely replaced by smaller and more focused partnerships. In our view, forging a partnership with industry can be a golden opportunity for both parties and can represent a true symbiosis. This type of project-specific collaboration is engendered by industry's desire to access very specific academic expertise that is required for the development of new technologies at the forefront of science. Since financial pressures do not allow companies to spend the time to acquire this expertise and even less to explore fundamental research, partnering with an academic laboratory whose research is related to the problem gives them a viable alternative. From an academic standpoint, it represents the perfect occasion to apply "pure science" research concepts to solve problems that benefit humanity. Moreover, it offers a unique opportunity for students to face challenges from the "real world" at an early stage of their career. Although not every problem in industry can be solved by research developments in academia, we argue that there is significant scientific overlap between these two seemingly disparate groups, thereby presenting an

  17. Academia-industry symbiosis in organic chemistry.

    PubMed

    Michaudel, Quentin; Ishihara, Yoshihiro; Baran, Phil S

    2015-03-17

    Collaboration between academia and industry is a growing phenomenon within the chemistry community. These sectors have long held strong ties since academia traditionally trains the future scientists of the corporate world, but the recent drastic decrease of public funding is motivating the academic world to seek more private grants. This concept of industrial "sponsoring" is not new, and in the past, some companies granted substantial amounts of money per annum to various academic institutions in exchange for prime access to all their scientific discoveries and inventions. However, academic and industrial interests were not always aligned, and therefore the investment has become increasingly difficult to justify from industry's point of view. With fluctuating macroeconomic factors, this type of unrestricted grant has become more rare and has been largely replaced by smaller and more focused partnerships. In our view, forging a partnership with industry can be a golden opportunity for both parties and can represent a true symbiosis. This type of project-specific collaboration is engendered by industry's desire to access very specific academic expertise that is required for the development of new technologies at the forefront of science. Since financial pressures do not allow companies to spend the time to acquire this expertise and even less to explore fundamental research, partnering with an academic laboratory whose research is related to the problem gives them a viable alternative. From an academic standpoint, it represents the perfect occasion to apply "pure science" research concepts to solve problems that benefit humanity. Moreover, it offers a unique opportunity for students to face challenges from the "real world" at an early stage of their career. Although not every problem in industry can be solved by research developments in academia, we argue that there is significant scientific overlap between these two seemingly disparate groups, thereby presenting an

  18. Recurrent De Novo Mutations Affecting Residue Arg138 of Pyrroline-5-Carboxylate Synthase Cause a Progeroid Form of Autosomal-Dominant Cutis Laxa

    PubMed Central

    Fischer-Zirnsak, Björn; Escande-Beillard, Nathalie; Ganesh, Jaya; Tan, Yu Xuan; Al Bughaili, Mohammed; Lin, Angela E.; Sahai, Inderneel; Bahena, Paulina; Reichert, Sara L.; Loh, Abigail; Wright, Graham D.; Liu, Jaron; Rahikkala, Elisa; Pivnick, Eniko K.; Choudhri, Asim F.; Krüger, Ulrike; Zemojtel, Tomasz; van Ravenswaaij-Arts, Conny; Mostafavi, Roya; Stolte-Dijkstra, Irene; Symoens, Sofie; Pajunen, Leila; Al-Gazali, Lihadh; Meierhofer, David; Robinson, Peter N.; Mundlos, Stefan; Villarroel, Camilo E.; Byers, Peter; Masri, Amira; Robertson, Stephen P.; Schwarze, Ulrike; Callewaert, Bert; Reversade, Bruno; Kornak, Uwe

    2015-01-01

    Progeroid disorders overlapping with De Barsy syndrome (DBS) are collectively denoted as autosomal-recessive cutis laxa type 3 (ARCL3). They are caused by biallelic mutations in PYCR1 or ALDH18A1, encoding pyrroline-5-carboxylate reductase 1 and pyrroline-5-carboxylate synthase (P5CS), respectively, which both operate in the mitochondrial proline cycle. We report here on eight unrelated individuals born to non-consanguineous families clinically diagnosed with DBS or wrinkly skin syndrome. We found three heterozygous mutations in ALDH18A1 leading to amino acid substitutions of the same highly conserved residue, Arg138 in P5CS. A de novo origin was confirmed in all six probands for whom parental DNA was available. Using fibroblasts from affected individuals and heterologous overexpression, we found that the P5CS-p.Arg138Trp protein was stable and able to interact with wild-type P5CS but showed an altered sub-mitochondrial distribution. A reduced size upon native gel electrophoresis indicated an alteration of the structure or composition of P5CS mutant complex. Furthermore, we found that the mutant cells had a reduced P5CS enzymatic activity leading to a delayed proline accumulation. In summary, recurrent de novo mutations, affecting the highly conserved residue Arg138 of P5CS, cause an autosomal-dominant form of cutis laxa with progeroid features. Our data provide insights into the etiology of cutis laxa diseases and will have immediate impact on diagnostics and genetic counseling. PMID:26320891

  19. A mutation creating a potential illegitimate microRNA target site in the myostatin gene affects muscularity in sheep.

    PubMed

    Clop, Alex; Marcq, Fabienne; Takeda, Haruko; Pirottin, Dimitri; Tordoir, Xavier; Bibé, Bernard; Bouix, Jacques; Caiment, Florian; Elsen, Jean-Michel; Eychenne, Francis; Larzul, Catherine; Laville, Elisabeth; Meish, Françoise; Milenkovic, Dragan; Tobin, James; Charlier, Carole; Georges, Michel

    2006-07-01

    Texel sheep are renowned for their exceptional meatiness. To identify the genes underlying this economically important feature, we performed a whole-genome scan in a Romanov x Texel F2 population. We mapped a quantitative trait locus with a major effect on muscle mass to chromosome 2 and subsequently fine-mapped it to a chromosome interval encompassing the myostatin (GDF8) gene. We herein demonstrate that the GDF8 allele of Texel sheep is characterized by a G to A transition in the 3' UTR that creates a target site for mir1 and mir206, microRNAs (miRNAs) that are highly expressed in skeletal muscle. This causes translational inhibition of the myostatin gene and hence contributes to the muscular hypertrophy of Texel sheep. Analysis of SNP databases for humans and mice demonstrates that mutations creating or destroying putative miRNA target sites are abundant and might be important effectors of phenotypic variation.

  20. Genetic and epigenetic mutations affect the DNA binding capability of human ZFP57 in transient neonatal diabetes type 1.

    PubMed

    Baglivo, Ilaria; Esposito, Sabrina; De Cesare, Lucia; Sparago, Angela; Anvar, Zahra; Riso, Vincenzo; Cammisa, Marco; Fattorusso, Roberto; Grimaldi, Giovanna; Riccio, Andrea; Pedone, Paolo V

    2013-05-21

    In the mouse, ZFP57 contains three classical Cys2His2 zinc finger domains (ZF) and recognizes the methylated TGC(met)CGC target sequence using the first and the second ZFs. In this study, we demonstrate that the human ZFP57 (hZFP57) containing six Cys2His2 ZFs, binds the same methylated sequence through the third and the fourth ZFs, and identify the aminoacids critical for DNA interaction. In addition, we present evidences indicating that hZFP57 mutations and hypomethylation of the TNDM1 ICR both associated with Transient Neonatal Diabetes Mellitus type 1 result in loss of hZFP57 binding to the TNDM1 locus, likely causing PLAGL1 activation.

  1. [A point mutation in the coat protein gene affects long distance transport of the tobacco mosaic virus].

    PubMed

    Koshkina, T E; Baranova, E N; Zavriev, S K

    2003-01-01

    A mutation resulting in substitution of positively charged Lys53 with negatively charged Glu in the coat protein was introduced in the infectious cDNA copy of the genome of wild-type tobacco mosaic virus strain U1. Kinetic analysis of long-distance virus transport in plants showed that systemic distribution of the mutant virus was delayed by 5-6 days as compared with the wild-type one. On evidence of RNA sequencing in the mutant progeny, Glu50 of the coat protein was substituted with Lys after passage I to compensate for the loss of the positive charge at position 53. Electron microscopy revealed atypical inclusions (rodlike structures, multiple electron-dense globular particles) in the nuclear interchromatin space of leaf mesophyll cells infected with the mutant but not with the wild-type virus. PMID:12942648

  2. In Azospirillum brasilense, mutations in flmA or flmB genes affect polar flagellum assembly, surface polysaccharides, and attachment to maize roots.

    PubMed

    Rossi, Fernando Ariel; Medeot, Daniela Beatriz; Liaudat, Juan Pablo; Pistorio, Mariano; Jofré, Edgardo

    2016-09-01

    Azospirillum brasilense is a soil bacterium capable of promoting plant growth. Several surface components were previously reported to be involved in the attachment of A. brasilense to root plants. Among these components are the exopolysaccharide (EPS), lipopolysaccharide (LPS) and the polar flagellum. Flagellin from polar flagellum is glycosylated and it was suggested that genes involved in such a posttranslational modification are the same ones involved in the biosynthesis of sugars present in the O-antigen of the LPS. In this work, we report on the characterization of two homologs present in A. brasilense Cd, to the well characterized flagellin modification genes, flmA and flmB, from Aeromonas caviae. We show that mutations in either flmA or flmB genes of A. brasilense resulted in non-motile cells due to alterations in the polar flagellum assembly. Moreover, these mutations also affected the capability of A. brasilense cells to adsorb to maize roots and to produce LPS and EPS. By generating a mutant containing the polar flagellum affected in their rotation, we show the importance of the bacterial motility for the early colonization of maize roots.

  3. Mutation of a C-Terminal Motif Affects Kaposi's Sarcoma-Associated Herpesvirus ORF57 RNA Binding, Nuclear Trafficking, and Multimerization ▿

    PubMed Central

    Taylor, Adam; Jackson, Brian R.; Noerenberg, Marko; Hughes, David J.; Boyne, James R.; Verow, Mark; Harris, Mark; Whitehouse, Adrian

    2011-01-01

    The Kaposi's sarcoma-associated herpesvirus (KSHV) ORF57 protein is essential for virus lytic replication. ORF57 regulates virus gene expression at multiple levels, enhancing transcription, stability, nuclear export, and translation of viral transcripts. To enhance the nuclear export of viral intronless transcripts, ORF57 (i) binds viral intronless mRNAs, (ii) shuttles between the nucleus, nucleolus, and the cytoplasm, and (iii) interacts with multiple cellular nuclear export proteins to access the TAP-mediated nuclear export pathway. We investigated the implications on the subcellular trafficking, cellular nuclear export factor recruitment, and ultimately nuclear mRNA export of an ORF57 protein unable to bind RNA. We observed that mutation of a carboxy-terminal RGG motif, which prevents RNA binding, affects the subcellular localization and nuclear trafficking of the ORF57 protein, suggesting that it forms subnuclear aggregates. Further analysis of the mutant shows that although it still retains the ability to interact with cellular nuclear export proteins, it is unable to export viral intronless mRNAs from the nucleus. Moreover, computational molecular modeling and biochemical studies suggest that, unlike the wild-type protein, this mutant is unable to self-associate. Therefore, these results suggest the mutation of a carboxy-terminal RGG motif affects ORF57 RNA binding, nuclear trafficking, and multimerization. PMID:21593148

  4. Mutations in the WSAWSE and cytosolic domains of the erythropoietin receptor affect signal transduction and ligand binding and internalization.

    PubMed Central

    Quelle, D E; Quelle, F W; Wojchowski, D M

    1992-01-01

    The terminal development of erythroid progenitor cells is promoted in part through the interaction of erythropoietin (EPO) with its cell surface receptor. This receptor and a growing family of related cytokine receptors share homologous extracellular features, including a well-conserved WSXWS motif. To explore the functional significance of this motif in the murine EPO receptor, five WSAWSE mutants were prepared and their signal-transducing, ligand binding, and endocytotic properties were compared. EPO receptors mutated at tryptophan residues (W-232, W-235----G; W-235----G; W-235----F) failed to mediate EPO-induced growth or pp100 phosphorylation, while S-236----T and E-237----K mutants exhibited partial to full activity (50 to 100% of wild-type growth and induced phosphorylation). Ligand affinity was reduced for mutant receptors (two- to fivefold), yet expression at the cell surface for all receptors was nearly equivalent. Also, the ability of mutated receptors to internalize ligand was either markedly reduced or abolished (W-235----F), indicating a role for the WSAWSE region in hormone internalization. Interestingly, receptor forms lacking 97% of the cytosolic domain (no signal-transducing capacity; binding affinity reduced two- to threefold) internalized EPO efficiently. This and all WSAWSE receptor forms studied also mediated specific cross-linking of 125I-EPO to three accessory membrane proteins (M(r)s, 120,000, 105,000, and 93,000). These findings suggest that the WSAWSE domain of the EPO receptor is important for EPO-induced signal transduction and ligand internalization. In contrast, although the cytosolic domain is required for growth signaling, it appears nonessential for efficient endocytosis. Images PMID:1406645

  5. Mutations in BIN1 Associated with Centronuclear Myopathy Disrupt Membrane Remodeling by Affecting Protein Density and Oligomerization

    PubMed Central

    Wu, Tingting; Shi, Zheng; Baumgart, Tobias

    2014-01-01

    The regulation of membrane shapes is central to many cellular phenomena. Bin/Amphiphysin/Rvs (BAR) domain-containing proteins are key players for membrane remodeling during endocytosis, cell migration, and endosomal sorting. BIN1, which contains an N-BAR domain, is assumed to be essential for biogenesis of plasma membrane invaginations (T-tubules) in muscle tissues. Three mutations, K35N, D151N and R154Q, have been discovered so far in the BAR domain of BIN1 in patients with centronuclear myopathy (CNM), where impaired organization of T-tubules has been reported. However, molecular mechanisms behind this malfunction have remained elusive. None of the BIN1 disease mutants displayed a significantly compromised curvature sensing ability. However, two mutants showed impaired membrane tubulation both in vivo and in vitro, and displayed characteristically different behaviors. R154Q generated smaller membrane curvature compared to WT N-BAR. Quantification of protein density on membranes revealed a lower membrane-bound density for R154Q compared to WT and the other mutants, which appeared to be the primary reason for the observation of impaired deformation capacity. The D151N mutant was unable to tubulate liposomes under certain experimental conditions. At medium protein concentrations we found ‘budding’ structures on liposomes that we hypothesized to be intermediates during the tubulation process except for the D151N mutant. Chemical crosslinking assays suggested that the D151N mutation impaired protein oligomerization upon membrane binding. Although we found an insignificant difference between WT and K35N N-BAR in in vitro assays, depolymerizing actin in live cells allowed tubulation of plasma membranes through the K35N mutant. Our results provide insights into the membrane-involved pathophysiological mechanisms leading to human disease. PMID:24755653

  6. Mutations That Affect Transcription and Cyclic Amp-Crp Regulation of the Adenylate Cyclase Gene (Cya) of Salmonella Typhimurium

    PubMed Central

    Fandl, J. P.; Thorner, L. K.; Artz, S. W.

    1990-01-01

    We studied the expression of the cya promoter(s) in cya-lac fusion strains of Salmonella typhimurium and demonstrated cAMP receptor protein (CRP)-dependent repression by cAMP. Expression of cya was reduced about fourfold in cultures grown in acetate minimal medium as compared to cultures grown in glucose-6-phosphate minimal medium. Expression of cya was also reduced about fourfold by addition of 5 mM cAMP to cultures grown in glucose minimal medium. We constructed in vitro deletion and insertion mutations altering a major cya promoter (P2) and a putative CRP binding site overlapping P2. These mutations were recombined into the chromosome by allele replacement with M13mp::cya recombinant phages and the regulation of the mutant promoters was analyzed. A 4-bp deletion of the CRP binding site and a 4-bp insertion in this site nearly eliminated repression by cAMP. A mutant with the P2 promoter and the CRP binding site both deleted exhibited an 80% reduction in cya expression; the 20% residual expression was insensitive to cAMP repression. This mutant retained a Cya(+) phenotype. Taken together, the results establish that the cya gene is transcribed from multiple promoters one of which, P2, is negatively regulated by the cAMP-CRP complex. Correction for the contribution to transcription by the cAMP-CRP nonregulated cya promoters indicates that the P2 promoter is repressed at least eightfold by cAMP-CRP. PMID:2168849

  7. Using answer set programming to integrate RNA expression with signalling pathway information to infer how mutations affect ageing.

    PubMed

    Papatheodorou, Irene; Ziehm, Matthias; Wieser, Daniela; Alic, Nazif; Partridge, Linda; Thornton, Janet M

    2012-01-01

    A challenge of systems biology is to integrate incomplete knowledge on pathways with existing experimental data sets and relate these to measured phenotypes. Research on ageing often generates such incomplete data, creating difficulties in integrating RNA expression with information about biological processes and the phenotypes of ageing, including longevity. Here, we develop a logic-based method that employs Answer Set Programming, and use it to infer signalling effects of genetic perturbations, based on a model of the insulin signalling pathway. We apply our method to RNA expression data from Drosophila mutants in the insulin pathway that alter lifespan, in a foxo dependent fashion. We use this information to deduce how the pathway influences lifespan in the mutant animals. We also develop a method for inferring the largest common sub-paths within each of our signalling predictions. Our comparisons reveal consistent homeostatic mechanisms across both long- and short-lived mutants. The transcriptional changes observed in each mutation usually provide negative feedback to signalling predicted for that mutation. We also identify an S6K-mediated feedback in two long-lived mutants that suggests a crosstalk between these pathways in mutants of the insulin pathway, in vivo. By formulating the problem as a logic-based theory in a qualitative fashion, we are able to use the efficient search facilities of Answer Set Programming, allowing us to explore larger pathways, combine molecular changes with pathways and phenotype and infer effects on signalling in in vivo, whole-organism, mutants, where direct signalling stimulation assays are difficult to perform. Our methods are available in the web-service NetEffects: http://www.ebi.ac.uk/thornton-srv/software/NetEffects.

  8. Metabolic constraints for a novel symbiosis

    PubMed Central

    Sørensen, Megan E. S.; Cameron, Duncan D.; Brockhurst, Michael A.; Wood, A. Jamie

    2016-01-01

    Ancient evolutionary events are difficult to study because their current products are derived forms altered by millions of years of adaptation. The primary endosymbiotic event formed the first photosynthetic eukaryote resulting in both plants and algae, with vast consequences for life on Earth. The evolutionary time that passed since this event means the dominant mechanisms and changes that were required are obscured. Synthetic symbioses such as the novel interaction between Paramecium bursaria and the cyanobacterium Synechocystis PC6803, recently established in the laboratory, permit a unique window on the possible early trajectories of this critical evolutionary event. Here, we apply metabolic modelling, using flux balance analysis (FBA), to predict the metabolic adaptations necessary for this previously free-living symbiont to transition to the endosymbiotic niche. By enforcing reciprocal nutrient trading, we are able to predict the most efficient exchange nutrients for both host and symbiont. During the transition from free-living to obligate symbiosis, it is likely that the trading parameters will change over time, which leads in our model to discontinuous changes in the preferred exchange nutrients. Our results show the applicability of FBA modelling to ancient evolutionary transitions driven by metabolic exchanges, and predict how newly established endosymbioses, governed by conflict, will differ from a well-developed one that has reached a mutual-benefit state. PMID:27069664

  9. A Symbiosis: Carbon Monitoring and Carbon Management

    NASA Astrophysics Data System (ADS)

    Macauley, M.

    2015-12-01

    "We measure what we value and value what we measure." This old dictum characterizes the usefulness of carbon monitoring in serving society, both in advancing research on carbon cycles and in applying new scientific knowledge to help carbon management. Many attempts to design policy for carbon management have been limited, ineffective, or otherwise unsuccessful in part due to inadequate capacity to observe carbon sources and sinks with sufficient measurement certainty and at appropriate spatial scale. Too often, policy designers fail to understand the complexities of carbon science and carbon researchers fail to align at least a portion of their science goals with policy requirements. The carbon monitoring systems research and applications activities under the auspices of the US National Aeronautics and Space Administration have significantly advanced both science and applications. To further this necessary symbiosis, this paper will synthesize current and prospective spatial and temporal requirements for emerging policy needs, discuss likely requirements for measurement certainty, and draw lessons from experiences in policies designed to monitor and manage other natural resources for which scientific research necessarily influenced policy design and effectiveness.

  10. Bacterial communities associated with the lichen symbiosis.

    PubMed

    Bates, Scott T; Cropsey, Garrett W G; Caporaso, J Gregory; Knight, Rob; Fierer, Noah

    2011-02-01

    Lichens are commonly described as a mutualistic symbiosis between fungi and "algae" (Chlorophyta or Cyanobacteria); however, they also have internal bacterial communities. Recent research suggests that lichen-associated microbes are an integral component of lichen thalli and that the classical view of this symbiotic relationship should be expanded to include bacteria. However, we still have a limited understanding of the phylogenetic structure of these communities and their variability across lichen species. To address these knowledge gaps, we used bar-coded pyrosequencing to survey the bacterial communities associated with lichens. Bacterial sequences obtained from four lichen species at multiple locations on rock outcrops suggested that each lichen species harbored a distinct community and that all communities were dominated by Alphaproteobacteria. Across all samples, we recovered numerous bacterial phylotypes that were closely related to sequences isolated from lichens in prior investigations, including those from a lichen-associated Rhizobiales lineage (LAR1; putative N(2) fixers). LAR1-related phylotypes were relatively abundant and were found in all four lichen species, and many sequences closely related to other known N(2) fixers (e.g., Azospirillum, Bradyrhizobium, and Frankia) were recovered. Our findings confirm the presence of highly structured bacterial communities within lichens and provide additional evidence that these bacteria may serve distinct functional roles within lichen symbioses.

  11. Metabolic constraints for a novel symbiosis.

    PubMed

    Sørensen, Megan E S; Cameron, Duncan D; Brockhurst, Michael A; Wood, A Jamie

    2016-03-01

    Ancient evolutionary events are difficult to study because their current products are derived forms altered by millions of years of adaptation. The primary endosymbiotic event formed the first photosynthetic eukaryote resulting in both plants and algae, with vast consequences for life on Earth. The evolutionary time that passed since this event means the dominant mechanisms and changes that were required are obscured. Synthetic symbioses such as the novel interaction between Paramecium bursaria and the cyanobacterium Synechocystis PC6803, recently established in the laboratory, permit a unique window on the possible early trajectories of this critical evolutionary event. Here, we apply metabolic modelling, using flux balance analysis (FBA), to predict the metabolic adaptations necessary for this previously free-living symbiont to transition to the endosymbiotic niche. By enforcing reciprocal nutrient trading, we are able to predict the most efficient exchange nutrients for both host and symbiont. During the transition from free-living to obligate symbiosis, it is likely that the trading parameters will change over time, which leads in our model to discontinuous changes in the preferred exchange nutrients. Our results show the applicability of FBA modelling to ancient evolutionary transitions driven by metabolic exchanges, and predict how newly established endosymbioses, governed by conflict, will differ from a well-developed one that has reached a mutual-benefit state. PMID:27069664

  12. MiniCD4 protein resistance mutations affect binding to the HIV-1 gp120 CD4 binding site and decrease entry efficiency

    PubMed Central

    2012-01-01

    Background Binding of the viral envelope protein (Env), and particularly of its gp120 subunit, to the cellular CD4 receptor is the first essential step of the HIV-1 entry process. The CD4 binding site (CD4bs) of gp120, and especially a recessed cavity occupied by the CD4 Phe43 residue, are known to be highly conserved among the different circulating subtypes and therefore constitute particularly interesting targets for vaccine and drug design. The miniCD4 proteins are a promising class of CD4bs inhibitors. Studying virus evolution under pressure of CD4bs inhibitors could provide insight on the gp120-CD4 interaction and viral entry. Results The present study reports on the resistance induction of two subtype B HIV-1 against the most active miniCD4, M48U1, and its ancestor, M48, and how these mutated positions affect CD4bs recognition, entry efficiency, and sensitivity to other CD4bs inhibitors. Resistance against M48U1 was always associated with S375R/N substitution in both BaL and SF162; M48 resistance was associated with D474N substitution in SF162 and with H105Y substitution in BaL. In addition, some other mutations at position V255 and G471 were of importance for SF162 resistant viruses. Except for 474, all of these mutated positions are conserved, and introducing them into an SF162 Env expressing infectious molecular clone (pBRNL4.3 SF162) resulted in decreased entry efficiency. Furthermore, resistant mutants showed at least some cross-resistance towards other CD4bs inhibitors, the V3 monoclonal antibody 447-52D and some even against the monoclonal antibody 17b, of which the epitope overlaps the co-receptor binding site. Conclusions The mutations H105Y, V255M, S375R/N, G471R/E, and D474N are found to be involved in resistance towards M48 and M48U1. All mutated positions are part of, or in close proximity to, the CD4bs; most are highly conserved, and all have an impact on the entry efficiency, suggesting their importance for optimal virus infectivity. PMID

  13. DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis

    PubMed Central

    Floss, Daniela S.; Levy, Julien G.; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J.

    2013-01-01

    Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis. PMID:24297892

  14. DELLA proteins regulate arbuscule formation in arbuscular mycorrhizal symbiosis.

    PubMed

    Floss, Daniela S; Levy, Julien G; Lévesque-Tremblay, Véronique; Pumplin, Nathan; Harrison, Maria J

    2013-12-17

    Most flowering plants are able to form endosymbioses with arbuscular mycorrhizal fungi. In this mutualistic association, the fungus colonizes the root cortex and establishes elaborately branched hyphae, called arbuscules, within the cortical cells. Arbuscule development requires the cellular reorganization of both symbionts, and the resulting symbiotic interface functions in nutrient exchange. A plant symbiosis signaling pathway controls the development of the symbiosis. Several components of the pathway have been identified, but transcriptional regulators that control downstream pathways for arbuscule formation are still unknown. Here we show that DELLA proteins, which are repressors of gibberellic acid (GA) signaling and function at the nexus of several signaling pathways, are required for arbuscule formation. Arbuscule formation is severely impaired in a Medicago truncatula Mtdella1/Mtdella2 double mutant; GA treatment of wild-type roots phenocopies the della double mutant, and a dominant DELLA protein (della1-Δ18) enables arbuscule formation in the presence of GA. Ectopic expression of della1-Δ18 suggests that DELLA activity in the vascular tissue and endodermis is sufficient to enable arbuscule formation in the inner cortical cells. In addition, expression of della1-Δ18 restores arbuscule formation in the symbiosis signaling pathway mutant cyclops/ipd3, indicating an intersection between DELLA and symbiosis signaling for arbuscule formation. GA signaling also influences arbuscule formation in monocots, and a Green Revolution wheat variety carrying dominant DELLA alleles shows enhanced colonization but a limited growth response to arbuscular mycorrhizal symbiosis.

  15. A review of industrial symbiosis research: theory and methodology

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Zheng, Hongmei; Chen, Bin; Su, Meirong; Liu, Gengyuan

    2015-03-01

    The theory, methodologies, and case studies in the field of industrial symbiosis have been developing for nearly 30 years. In this paper, we trace the development history of industrial symbiosis, and review its current theoretical and methodological bases, as well as trends in current research. Based on the research gaps that we identify, we provide suggestions to guide the future development of this approach to permit more comprehensive analyses. Our theoretical review includes key definitions, a classification system, and a description of the formation and development mechanisms. We discuss methodological studies from the perspective of individual industrial metabolic processes and network analysis. Analyzing specific metabolic processes can help to characterize the exchanges of materials and energy, and to reveal the ecological performance and economic benefits of the symbiosis. Network analysis methods are increasingly being used to analyze both the structural and functional characteristics of a system. Our suggestions for future research focus on three aspects: how to quantitatively classify industrial symbiosis systems, monitor the dynamics of a developing industrial symbiosis system, and analyze its internal attributes more deeply.

  16. Cadherin mutation linked to resistance to Cry1Ac affects male paternity and sperm competition in Helicoverpa armigera

    PubMed Central

    Zhang, Haonan; Du, Bing; Higginson, Dawn M.; Carrière, Yves; Wu, Yidong

    2015-01-01

    Several lepidopteran pests of cotton have cadherin-based resistance to the Bacillus thuringiensis (Bt) toxin Cry1Ac. Cadherins are transmembrane proteins that mediate cell-cell adhesion and tissue morphogenesis, suggesting that fitness costs associated with cadherin mutations may be present in many aspects of life history. To evaluate whether cadherin-based resistance is associated with fitness costs reducing male paternity in Helicoverpa armigera, we examined the effects of a major cadherin resistance allele on sperm competition within and between male ejaculates. When homozygous resistant and susceptible males competed for fertilization of a homozygous resistant or susceptible female, fertilization success was high in males with a different cadherin genotype than females and low in males with the same cadherin genotype as females. Single matings between heterozygous males and susceptible females produced offspring within typical Mendelian ratios. Heterozygous males mated to resistant females, however, resulted in a disproportionate number of heterozygous offspring. While these results show that cadherin-based resistance to Cry1Ac has significant impacts on paternity in H. armigera, there was no evidence that costs associated with resistance consistently reduced male paternity. Rather, effects of cadherin-based resistance on paternity depended on interactions between male and female genotypes and differed when males or sperm competed for fertilization of females, which complicates assessment of impacts of cadherin resistance alleles on resistance evolution. PMID:25220924

  17. Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

    PubMed Central

    2010-01-01

    The Gram-negative bacterium Xanthomonas axonopodis pv. citri, the causal agent of citrus canker, is a major threat to the citrus industry worldwide. Although this is a leaf spot pathogen, it bears genes highly related to degradation of plant cell walls, which are typically found in plant pathogens that cause symptoms of tissue maceration. Little is known on Xac capacity to cause disease and hydrolyze cellulose. We investigated the contribution of various open reading frames on degradation of a cellulose compound by means of a global mutational assay to selectively screen for a defect in carboxymethyl cellulase (CMCase) secretion in X. axonopodis pv. citri. Screening on CMC agar revealed one mutant clone defective in extracellular glycanase activity, out of nearly 3,000 clones. The insertion was located in the xpsD gene, a component of the type II secretion system (T2SS) showing an influence in the ability of Xac to colonize tissues and hydrolyze cellulose. In summary, these data show for the first time, that X. axonopodis pv. citri is capable of hydrolyzing cellulose in a T2SS-dependent process. Furthermore, it was demonstrated that the ability to degrade cellulose contributes to the infection process as a whole. PMID:21637619

  18. Brassinosteroid/Sterol Synthesis and Plant Growth as Affected by lka and lkb Mutations of Pea1

    PubMed Central

    Nomura, Takahito; Kitasaka, Yukiko; Takatsuto, Suguru; Reid, James B.; Fukami, Motohiro; Yokota, Takao

    1999-01-01

    The dwarf pea (Pisum sativum) mutants lka and lkb are brassinosteroid (BR) insensitive and deficient, respectively. The dwarf phenotype of the lkb mutant was rescued to wild type by exogenous application of brassinolide and its biosynthetic precursors. Gas chromatography-mass spectrometry analysis of the endogenous sterols in this mutant revealed that it accumulates 24-methylenecholesterol and isofucosterol but is deficient in their hydrogenated products, campesterol and sitosterol. Feeding experiments using 2H-labeled 24-methylenecholesterol indicated that the lkb mutant is unable to isomerize and/or reduce the Δ24(28) double bond. Dwarfism of the lkb mutant is, therefore, due to BR deficiency caused by blocked synthesis of campesterol from 24-methylenecholesterol. The lkb mutation also disrupted sterol composition of the membranes, which, in contrast to those of the wild type, contained isofucosterol as the major sterol and lacked stigmasterol. The lka mutant was not BR deficient, because it accumulated castasterone. Like some gibberellin-insensitive dwarf mutants, overproduction of castasterone in the lka mutant may be ascribed to the lack of a feedback control mechanism due to impaired perception/signal transduction of BRs. The possibility that castasterone is a biologically active BR is discussed. PMID:10198111

  19. Point mutations in EBV gH that abrogate or differentially affect B cell and epithelial cell fusion

    SciTech Connect

    Wu Liguo; Hutt-Fletcher, Lindsey M. . E-mail: lhuttf@lsuhsc.edu

    2007-06-20

    Cell fusion mediated by Epstein-Barr virus requires three conserved glycoproteins, gB and gHgL, but activation is cell type specific. B cell fusion requires interaction between MHC class II and a fourth virus glycoprotein, gp42, which complexes non-covalently with gHgL. Epithelial cell fusion requires interaction between gHgL and a novel epithelial cell coreceptor and is blocked by excess gp42. We show here that gp42 interacts directly with gH and that point mutations in the region of gH recognized by an antibody that differentially inhibits epithelial and B cell fusion significantly impact both the core fusion machinery and cell-specific events. Substitution of alanine for glycine at residue 594 completely abrogates fusion with either B cells or epithelial cells. Substitution of alanine for glutamic acid at residue 595 reduces fusion with epithelial cells, greatly enhances fusion with B cells and allows low levels of B cell fusion even in the absence of gL.

  20. Molecular analysis of mutations affecting hprt mRNA splicing in human T-lymphocytes in vivo

    SciTech Connect

    Rossi, A.M. Pisa Univ. ); Tates, A.D.; van Zeeland, A.A.; Vrieling, H. )

    1992-01-01

    Molecular analysis of hypoxanthine-guanine phosphoribosyltransferase (hprt) cDNA from 6-thioguanine-resistant T-lymphocytes cloned from smoking and non-smoking adult donors showed that 35% of these mutants were defective in splicing of hprt mRNA. Among a set of 42 hprt splice mutants, the authors observed (1) complete loss of one or more exons, (2) partial loss of one exon, or (3) inclusion of part of an intron sequence between adjacent exons. Loss of exon 4 was significantly more frequent than of the other exons, suggesting that the sequences that regulate splicing of this exon are either larger than those of the other exons or especially prone to mutation. In order to identify the molecular nature of DNA alterations causing aberrant splicing of hprt mRNA, 17 splice mutants were analyzed in more detail by sequencing the genomic regions flanking the mis-spliced exon. Base pair substitutions or small deletions causing defective splicing were either detected in exon sequences or in splice site consensus sequences of introns.

  1. Novel and recurrent mutations in the TAT gene in Tunisian families affected with Richner-Hanhart syndrome.

    PubMed

    Bouyacoub, Yosra; Zribi, Hela; Azzouz, Hatem; Nasrallah, Fehmi; Abdelaziz, Rim Ben; Kacem, Monia; Rekaya, Ben; Messaoud, Olfa; Romdhane, Lilia; Charfeddine, Cherine; Bouziri, Mustapha; Bouziri, Sonia; Tebib, Neji; Mokni, Mourad; Kaabachi, Naziha; Boubaker, Samir; Abdelhak, Sonia

    2013-10-15

    Tyrosinemia type II, also designated as oculocutaneous tyrosinemia or Richner-Hanhart syndrome (RHS), is a very rare autosomal recessive disorder. In the present study, we report clinical features and molecular genetic investigation of the tyrosine aminotransferase (TAT) gene in two young patients, both born to consanguineous unions between first-degree cousins. These two unrelated families originated from Northern and Southern Tunisia. The clinical diagnosis was based on the observation of several complications related to Richner-Hanhart syndrome: recurrent eye redness, tearing and burning pain, photophobia, bilateral pseudodendritic keratitis, an erythematous and painful focal palmo-plantar hyperkeratosis and a mild delay of mental development. The diagnosis was confirmed by biochemical analysis. Sequencing of the TAT gene revealed the presence of a previously reported missense mutation (c.452G>A, p.Cys151Tyr) in a Tunisian family, and a novel G duplication (c.869dupG, p.Trp291Leufs 6). Early diagnosis of RHS and protein-restricted diet are crucial to reduce the risk and the severity of long-term complications of hypertyrosinemia such as intellectual disability.

  2. Glycerol Hypersensitivity in a Drosophila Model for Glycerol Kinase Deficiency Is Affected by Mutations in Eye Pigmentation Genes

    PubMed Central

    Wightman, Patrick J.; Jackson, George R.; Dipple, Katrina M.

    2012-01-01

    Glycerol kinase plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP dependent reaction. In humans, glycerol kinase deficiency results in a wide range of phenotypic variability; patients can have severe metabolic and CNS abnormalities, while others possess hyperglycerolemia and glyceroluria with no other apparent phenotype. In an effort to help understand the pathogenic mechanisms underlying the phenotypic variation, we have created a Drosophila model for glycerol kinase deficiency by RNAi targeting of dGyk (CG18374) and dGK (CG7995). As expected, RNAi flies have reduced glycerol kinase RNA expression, reduced phosphorylation activity and elevated glycerol levels. Further investigation revealed these flies to be hypersensitive to fly food supplemented with glycerol. Due to the hygroscopic nature of glycerol, we predict glycerol hypersensitivity is a result of greater susceptibility to desiccation, suggesting glycerol kinase to play an important role in desiccation resistance in insects. To evaluate a role for genetic modifier loci in determining severity of the glycerol hypersensitivity observed in knockdown flies, we performed a preliminary screen of lethal transposon insertion mutant flies using a glycerol hypersensitive survivorship assay. We demonstrate that this type of screen can identify both enhancer and suppressor genetic loci of glycerol hypersensitivity. Furthermore, we found that the glycerol hypersensitivity phenotype can be enhanced or suppressed by null mutations in eye pigmentation genes. Taken together, our data suggest proteins encoded by eye pigmentation genes play an important role in desiccation resistance and that eye pigmentation genes are strong modifiers of the glycerol hypersensitive phenotype identified in our Drosophila model for glycerol kinase deficiency. PMID:22427807

  3. Integrating transcriptome and genome re-sequencing data to identify key genes and mutations affecting chicken eggshell qualities.

    PubMed

    Zhang, Quan; Zhu, Feng; Liu, Long; Zheng, Chuan Wei; Wang, De He; Hou, Zhuo Cheng; Ning, Zhong Hua

    2015-01-01

    Eggshell damages lead to economic losses in the egg production industry and are a threat to human health. We examined 49-wk-old Rhode Island White hens (Gallus gallus) that laid eggs having shells with significantly different strengths and thicknesses. We used HiSeq 2000 (Illumina) sequencing to characterize the chicken transcriptome and whole genome to identify the key genes and genetic mutations associated with eggshell calcification. We identified a total of 14,234 genes expressed in the chicken uterus, representing 89% of all annotated chicken genes. A total of 889 differentially expressed genes were identified by comparing low eggshell strength (LES) and normal eggshell strength (NES) genomes. The DEGs are enriched in calcification-related processes, including calcium ion transport and calcium signaling pathways as revealed by gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis. Some important matrix proteins, such as OC-116, LTF and SPP1, were also expressed differentially between two groups. A total of 3,671,919 single-nucleotide polymorphisms (SNPs) and 508,035 Indels were detected in protein coding genes by whole-genome re-sequencing, including 1775 non-synonymous variations and 19 frame-shift Indels in DEGs. SNPs and Indels found in this study could be further investigated for eggshell traits. This is the first report to integrate the transcriptome and genome re-sequencing to target the genetic variations which decreased the eggshell qualities. These findings further advance our understanding of eggshell calcification in the chicken uterus.

  4. Symbiosis-induced adaptation to oxidative stress.

    PubMed

    Richier, Sophie; Furla, Paola; Plantivaux, Amandine; Merle, Pierre-Laurent; Allemand, Denis

    2005-01-01

    Cnidarians in symbiosis with photosynthetic protists must withstand daily hyperoxic/anoxic transitions within their host cells. Comparative studies between symbiotic (Anemonia viridis) and non-symbiotic (Actinia schmidti) sea anemones show striking differences in their response to oxidative stress. First, the basal expression of SOD is very different. Symbiotic animal cells have a higher isoform diversity (number and classes) and a higher activity than the non-symbiotic cells. Second, the symbiotic animal cells of A. viridis also maintain unaltered basal values for cellular damage when exposed to experimental hyperoxia (100% O(2)) or to experimental thermal stress (elevated temperature +7 degrees C above ambient). Under such conditions, A. schmidti modifies its SOD activity significantly. Electrophoretic patterns diversify, global activities diminish and cell damage biomarkers increase. These data suggest symbiotic cells adapt to stress while non-symbiotic cells remain acutely sensitive. In addition to being toxic, high O(2) partial pressure (P(O(2))) may also constitute a preconditioning step for symbiotic animal cells, leading to an adaptation to the hyperoxic condition and, thus, to oxidative stress. Furthermore, in aposymbiotic animal cells of A. viridis, repression of some animal SOD isoforms is observed. Meanwhile, in cultured symbionts, new activity bands are induced, suggesting that the host might protect its zooxanthellae in hospite. Similar results have been observed in other symbiotic organisms, such as the sea anemone Aiptasia pulchella and the scleractinian coral Stylophora pistillata. Molecular or physical interactions between the two symbiotic partners may explain such variations in SOD activity and might confer oxidative stress tolerance to the animal host. PMID:15634847

  5. Symbiosis-induced adaptation to oxidative stress.

    PubMed

    Richier, Sophie; Furla, Paola; Plantivaux, Amandine; Merle, Pierre-Laurent; Allemand, Denis

    2005-01-01

    Cnidarians in symbiosis with photosynthetic protists must withstand daily hyperoxic/anoxic transitions within their host cells. Comparative studies between symbiotic (Anemonia viridis) and non-symbiotic (Actinia schmidti) sea anemones show striking differences in their response to oxidative stress. First, the basal expression of SOD is very different. Symbiotic animal cells have a higher isoform diversity (number and classes) and a higher activity than the non-symbiotic cells. Second, the symbiotic animal cells of A. viridis also maintain unaltered basal values for cellular damage when exposed to experimental hyperoxia (100% O(2)) or to experimental thermal stress (elevated temperature +7 degrees C above ambient). Under such conditions, A. schmidti modifies its SOD activity significantly. Electrophoretic patterns diversify, global activities diminish and cell damage biomarkers increase. These data suggest symbiotic cells adapt to stress while non-symbiotic cells remain acutely sensitive. In addition to being toxic, high O(2) partial pressure (P(O(2))) may also constitute a preconditioning step for symbiotic animal cells, leading to an adaptation to the hyperoxic condition and, thus, to oxidative stress. Furthermore, in aposymbiotic animal cells of A. viridis, repression of some animal SOD isoforms is observed. Meanwhile, in cultured symbionts, new activity bands are induced, suggesting that the host might protect its zooxanthellae in hospite. Similar results have been observed in other symbiotic organisms, such as the sea anemone Aiptasia pulchella and the scleractinian coral Stylophora pistillata. Molecular or physical interactions between the two symbiotic partners may explain such variations in SOD activity and might confer oxidative stress tolerance to the animal host.

  6. On Human Symbiosis and the Vicissitudes of Individuation. Infantile Psychosis, Volume 1.

    ERIC Educational Resources Information Center

    Mahler, Margaret S.

    The concepts of symbiosis and separation-individuation are explained, and the symbiosis theory of infantile psychosis is presented. Diagnostic considerations and clinical cases of child psychosis are reviewed; prototypes of mother-child interaction are described; and therapy is discussed. A summary of the symbiosis theory and a bibliography of…

  7. [Effects of monorecessive and double recessive mutations affecting coat color on the monoamine content of the brain of the American mink (Mustela vison Schreber, 1777)].

    PubMed

    Trapezov, O V; Trapezova, L I; alekhina, T A; Klochkov, D V; Ivanov, Iu N

    2009-12-01

    The effects of mutations affecting the coat color on the dopamine, noradrenaline, and serotonin contents of the hypothalamus and brainstem of the American mink have been studied. The sample comprised standard (+/+) and mutant minks, including the monorecessive pastel (b/b), silver-blue (p/p), and white hedlund (h/h) and the combination double recessive sapphire (a/a p/p) and pearl (k/k p/p) ones. The dopamine content of the brainstem of the monorecessive pastel (b/b) and silver-blue (p/p) minks has been found to be higher than in standard (+/+) minks. Conversely, the homozigosity for two coat color loci in double recessive pearl minks (k/k p/p) significantly decreases the noradrenaline and serotonin contents of the hypothalamus. In addition, monorecessive and double recessive minks differ from each other in the serotonin contents of the midbrain and medulla.

  8. Host and φx 174 Mutations Affecting the Morphogenesis or Stabilization of the 50s Complex, a Single-Stranded DNA Synthesizing Intermediate

    PubMed Central

    Ekechukwu, M. C.; Oberste, D. J.; Fane, B. A.

    1995-01-01

    The morphogenetic pathway of bacteriophage φX 174 was investigated in rep mutant hosts that specifically block stage III single-stranded DNA synthesis. The defects conferred by the mutant rep protein most likely affect the formation or stabilization of the 50S complex, a single-stranded DNA synthesizing intermediate, which consists of a viral prohead and a DNA replicating intermediate (preinitiation complex). φX 174 mutants, ogr(rep), which restore the ability to propagate in the mutant rep hosts, were isolated. The ogr(rep) mutations confer amino acid substitutions in the viral coat protein, a constituent of the prohead, and the viral A protein, a constituent of the preinitiation complex. Four of the six coat protein substitutions are localized on or near the twofold axis of symmetry in the atomic structure of the mature virion. PMID:7498760

  9. [LEGUME-RHIZOBIUM SYMBIOSIS PROTEOMICS: ACHIEVEMENTS AND PERSPECTIVES].

    PubMed

    Kondratiuk, Iu Iu; Mamenko, P M; Kots, S Ya

    2015-01-01

    The present review contains results of proteomic researches of legume-rhizobium symbiosis. The technical difficulties associated with the methods of obtaining protein extracts from symbiotic structures and ways of overcoming them were discussed. The changes of protein synthesis under formation and functioning of symbiotic structures were shown. Special attention has been given to the importance of proteomic studies of plant-microbe structures in the formation of adaptation strategies under adverse environmental conditions. The technical and conceptual perspectives of legume-rhizobium symbiosis proteomics were shown.

  10. Evolving together: the biology of symbiosis, part 1

    PubMed Central

    2000-01-01

    Symbioses, prolonged associations between organisms often widely separated phylogenetically, are more common in biology than we once thought and have been neglected as a phenomenon worthy of study on its own merits. Extending along a dynamic continuum from antagonistic to cooperative and often involving elements of both antagonism and mutualism, symbioses involve pathogens, commensals, and mutualists interacting in myriad ways over the evolutionary history of the involved “partners.” In this first of 2 parts, some remarkable examples of symbiosis will be explored, from the coral-algal symbiosis and nitrogen fixation to the great diversity of dietary specializations enabled by the gastrointestinal microbiota of animals. PMID:16389385

  11. Mutations in RNA Polymerase Bridge Helix and Switch Regions Affect Active-Site Networks and Transcript-Assisted Hydrolysis

    PubMed Central

    Zhang, Nan; Schäfer, Jorrit; Sharma, Amit; Rayner, Lucy; Zhang, Xiaodong; Tuma, Roman; Stockley, Peter; Buck, Martin

    2015-01-01

    In bacterial RNA polymerase (RNAP), the bridge helix and switch regions form an intricate network with the catalytic active centre and the main channel. These interactions are important for catalysis, hydrolysis and clamp domain movement. By targeting conserved residues in Escherichia coli RNAP, we are able to show that functions of these regions are differentially required during σ70-dependent and the contrasting σ54-dependent transcription activations and thus potentially underlie the key mechanistic differences between the two transcription paradigms. We further demonstrate that the transcription factor DksA directly regulates σ54-dependent activation both positively and negatively. This finding is consistent with the observed impacts of DksA on σ70-dependent promoters. DksA does not seem to significantly affect RNAP binding to a pre-melted promoter DNA but affects extensively activity at the stage of initial RNA synthesis on σ54-regulated promoters. Strikingly, removal of the σ54 Region I is sufficient to invert the action of DksA (from stimulation to inhibition or vice versa) at two test promoters. The RNAP mutants we generated also show a strong propensity to backtrack. These mutants increase the rate of transcript-hydrolysis cleavage to a level comparable to that seen in the Thermus aquaticus RNAP even in the absence of a non-complementary nucleotide. These novel phenotypes imply an important function of the bridge helix and switch regions as an anti-backtracking ratchet and an RNA hydrolysis regulator. PMID:26365052

  12. Mutations in RNA Polymerase Bridge Helix and Switch Regions Affect Active-Site Networks and Transcript-Assisted Hydrolysis.

    PubMed

    Zhang, Nan; Schäfer, Jorrit; Sharma, Amit; Rayner, Lucy; Zhang, Xiaodong; Tuma, Roman; Stockley, Peter; Buck, Martin

    2015-11-01

    In bacterial RNA polymerase (RNAP), the bridge helix and switch regions form an intricate network with the catalytic active centre and the main channel. These interactions are important for catalysis, hydrolysis and clamp domain movement. By targeting conserved residues in Escherichia coli RNAP, we are able to show that functions of these regions are differentially required during σ(70)-dependent and the contrasting σ(54)-dependent transcription activations and thus potentially underlie the key mechanistic differences between the two transcription paradigms. We further demonstrate that the transcription factor DksA directly regulates σ(54)-dependent activation both positively and negatively. This finding is consistent with the observed impacts of DksA on σ(70)-dependent promoters. DksA does not seem to significantly affect RNAP binding to a pre-melted promoter DNA but affects extensively activity at the stage of initial RNA synthesis on σ(54)-regulated promoters. Strikingly, removal of the σ(54) Region I is sufficient to invert the action of DksA (from stimulation to inhibition or vice versa) at two test promoters. The RNAP mutants we generated also show a strong propensity to backtrack. These mutants increase the rate of transcript-hydrolysis cleavage to a level comparable to that seen in the Thermus aquaticus RNAP even in the absence of a non-complementary nucleotide. These novel phenotypes imply an important function of the bridge helix and switch regions as an anti-backtracking ratchet and an RNA hydrolysis regulator.

  13. Mutations in RNA Polymerase Bridge Helix and Switch Regions Affect Active-Site Networks and Transcript-Assisted Hydrolysis.

    PubMed

    Zhang, Nan; Schäfer, Jorrit; Sharma, Amit; Rayner, Lucy; Zhang, Xiaodong; Tuma, Roman; Stockley, Peter; Buck, Martin

    2015-11-01

    In bacterial RNA polymerase (RNAP), the bridge helix and switch regions form an intricate network with the catalytic active centre and the main channel. These interactions are important for catalysis, hydrolysis and clamp domain movement. By targeting conserved residues in Escherichia coli RNAP, we are able to show that functions of these regions are differentially required during σ(70)-dependent and the contrasting σ(54)-dependent transcription activations and thus potentially underlie the key mechanistic differences between the two transcription paradigms. We further demonstrate that the transcription factor DksA directly regulates σ(54)-dependent activation both positively and negatively. This finding is consistent with the observed impacts of DksA on σ(70)-dependent promoters. DksA does not seem to significantly affect RNAP binding to a pre-melted promoter DNA but affects extensively activity at the stage of initial RNA synthesis on σ(54)-regulated promoters. Strikingly, removal of the σ(54) Region I is sufficient to invert the action of DksA (from stimulation to inhibition or vice versa) at two test promoters. The RNAP mutants we generated also show a strong propensity to backtrack. These mutants increase the rate of transcript-hydrolysis cleavage to a level comparable to that seen in the Thermus aquaticus RNAP even in the absence of a non-complementary nucleotide. These novel phenotypes imply an important function of the bridge helix and switch regions as an anti-backtracking ratchet and an RNA hydrolysis regulator. PMID:26365052

  14. Pyrosequencing-Based Assays for Rapid Detection of HER2 and HER3 Mutations in Clinical Samples Uncover an E332E Mutation Affecting HER3 in Retroperitoneal Leiomyosarcoma

    PubMed Central

    González-Alonso, Paula; Chamizo, Cristina; Moreno, Víctor; Madoz-Gúrpide, Juan; Carvajal, Nerea; Daoud, Lina; Zazo, Sandra; Martín-Aparicio, Ester; Cristóbal, Ion; Rincón, Raúl; García-Foncillas, Jesús; Rojo, Federico

    2015-01-01

    Mutations in Human Epidermal Growth Factor Receptors (HER) are associated with poor prognosis of several types of solid tumors. Although HER-mutation detection methods are currently available, such as Next-Generation Sequencing (NGS), alternative pyrosequencing allow the rapid characterization of specific mutations. We developed specific PCR-based pyrosequencing assays for identification of most prevalent HER2 and HER3 mutations, including S310F/Y, R678Q, L755M/P/S/W, V777A/L/M, 774-776 insertion, and V842I mutations in HER2, as well as M91I, V104M/L, D297N/V/Y, and E332E/K mutations in HER3. We tested 85 Formalin Fixed and Paraffin Embbeded (FFPE) samples and we detected three HER2-V842I mutations in colorectal carcinoma (CRC), ovarian carcinoma, and pancreatic carcinoma patients, respectively, and a HER2-L755M mutation in a CRC specimen. We also determined the presence of a HER3-E332K mutation in an urothelial carcinoma sample, and two HER3-D297Y mutations, in both gastric adenocarcinoma and CRC specimens. The D297Y mutation was previously detected in breast and gastric tumors, but not in CRC. Moreover, we found a not-previously-described HER3-E332E synonymous mutation in a retroperitoneal leiomyosarcoma patient. The pyrosequencing assays presented here allow the detection and characterization of specific HER2 and HER3 mutations. These pyrosequencing assays might be implemented in routine diagnosis for molecular characterization of HER2/HER3 receptors as an alternative to complex NGS approaches. PMID:26287187

  15. Persistence of DNMT3A R882 mutations during remission does not adversely affect outcomes of patients with acute myeloid leukaemia

    PubMed Central

    Bhatnagar, Bhavana; Eisfeld, Ann-Kathrin; Nicolet, Deedra; Mrózek, Krzysztof; Blachly, James S.; Orwick, Shelley; Lucas, David M.; Kohlschmidt, Jessica; Blum, William; Kolitz, Jonathan E.; Stone, Richard M.; Bloomfield, Clara D.; Byrd, John C.

    2016-01-01

    Summary Somatic mutation of the DNMT3A gene at the arginine R882 site is common in acute myeloid leukaemia (AML). The prognostic significance of DNMT3A R882 mutation clearance, using traditional diagnostic next generation sequencing (NGS) methods, during complete remission (CR) in AML patients is controversial. We examined the impact of clearing DNMT3A R882 mutations at diagnosis to the detectable threshold of <3% during CR on outcome in 56 adult AML patients. Mutational remission, defined as clearance of pre-treatment DNMT3A R882 and all other AML-associated mutations to a variant allele frequency <3%, occurred in 14 patients whereas persistent DNMT3A R882 mutations were observed in 42 patients. There were no significant differences in disease-free or overall survival between patients with and without DNMT3A R882 mutation clearance. Patients with persistent DNMT3A R882 who cleared all other AML mutations and did not acquire new mutations (n = 30), trended towards longer disease-free survival (1·6 vs. 0·6 years, P = 0·06) than patients with persistence of DNMT3A R882, in addition to other mutations or acquisition of new AML-associated mutations, such as those in TET2, JAK2, ASXL1 and TP53 (n = 12). These data demonstrate that DNMT3A R882 mutations, as assessed by traditional NGS methods, persist in the majority of AML patients in CR. PMID:27476855

  16. Quorum sensing in the squid-Vibrio symbiosis.

    PubMed

    Verma, Subhash C; Miyashiro, Tim

    2013-08-07

    Quorum sensing is an intercellular form of communication that bacteria use to coordinate group behaviors such as biofilm formation and the production of antibiotics and virulence factors. The term quorum sensing was originally coined to describe the mechanism underlying the onset of luminescence production in cultures of the marine bacterium Vibrio fischeri. Luminescence and, more generally, quorum sensing are important for V. fischeri to form a mutualistic symbiosis with the Hawaiian bobtail squid, Euprymna scolopes. The symbiosis is established when V. fischeri cells migrate via flagella-based motility from the surrounding seawater into a specialized structure injuvenile squid called the light organ. The cells grow to high cell densities within the light organ where the infection persists over the lifetime of the animal. A hallmark of a successful symbiosis is the luminescence produced by V. fischeri that camouflages the squid at night by eliminating its shadow within the water column. While the regulatory networks governing quorum sensing are critical for properly regulating V. fischeri luminescence within the squid light organ, they also regulate luminescence-independent processes during symbiosis. In this review, we discuss the quorum-sensing network of V. fischeri and highlight its impact at various stages during host colonization.

  17. Quorum Sensing in the Squid-Vibrio Symbiosis

    PubMed Central

    Verma, Subhash C.; Miyashiro, Tim

    2013-01-01

    Quorum sensing is an intercellular form of communication that bacteria use to coordinate group behaviors such as biofilm formation and the production of antibiotics and virulence factors. The term quorum sensing was originally coined to describe the mechanism underlying the onset of luminescence production in cultures of the marine bacterium Vibrio fischeri. Luminescence and, more generally, quorum sensing are important for V. fischeri to form a mutualistic symbiosis with the Hawaiian bobtail squid, Euprymna scolopes. The symbiosis is established when V. fischeri cells migrate via flagella-based motility from the surrounding seawater into a specialized structure injuvenile squid called the light organ. The cells grow to high cell densities within the light organ where the infection persists over the lifetime of the animal. A hallmark of a successful symbiosis is the luminescence produced by V. fischeri that camouflages the squid at night by eliminating its shadow within the water column. While the regulatory networks governing quorum sensing are critical for properly regulating V. fischeri luminescence within the squid light organ, they also regulate luminescence-independent processes during symbiosis. In this review, we discuss the quorum-sensing network of V. fischeri and highlight its impact at various stages during host colonization. PMID:23965960

  18. Signaling events during initiation of arbuscular mycorrhizal symbiosis.

    PubMed

    Schmitz, Alexa M; Harrison, Maria J

    2014-03-01

    Under nutrient-limiting conditions, plants will enter into symbiosis with arbuscular mycorrhizal (AM) fungi for the enhancement of mineral nutrient acquisition from the surrounding soil. AM fungi live in close, intracellular association with plant roots where they transfer phosphate and nitrogen to the plant in exchange for carbon. They are obligate fungi, relying on their host as their only carbon source. Much has been discovered in the last decade concerning the signaling events during initiation of the AM symbiosis, including the identification of signaling molecules generated by both partners. This signaling occurs through symbiosis-specific gene products in the host plant, which are indispensable for normal AM development. At the same time, plants have adapted complex mechanisms for avoiding infection by pathogenic fungi, including an innate immune response to general microbial molecules, such as chitin present in fungal cell walls. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is still uncertain. In this review, we present a summary of the molecular signals and their elicited responses during initiation of the AM symbiosis, including plant immune responses and their suppression.

  19. [HYDROBIOCENOSES--A MODEL SYSTEM OF ASSOCIATIVE SYMBIOSIS].

    PubMed

    Nemtseva, N V

    2015-01-01

    Evolutionary formed mechanisms, that preserve and support microorganism populations in any environmental conditions up to extreme, that are the base of survival strategy, were analyzed. Natural mechanisms, that support biodiversity and stability of ecosystems of natural water bodies, are shown to determine structuredness of hydrobiont communities by associative symbiosis type.

  20. Sugar for my honey: carbohydrate partitioning in ectomycorrhizal symbiosis.

    PubMed

    Nehls, Uwe; Grunze, Nina; Willmann, Martin; Reich, Marlis; Küster, Helge

    2007-01-01

    Simple, readily utilizable carbohydrates, necessary for growth and maintenance of large numbers of microbes are rare in forest soils. Among other types of mutualistic interactions, the formation of ectomycorrhizas, a symbiosis between tree roots and certain soil fungi, is a way to overcome nutrient and carbohydrate limitations typical for many forest ecosystems. Ectomycorrhiza formation is typical for trees in boreal and temperate forests of the northern hemisphere and alpine regions world-wide. The main function of this symbiosis is the exchange of fungus-derived nutrients for plant-derived carbohydrates, enabling the colonization of mineral nutrient-poor environments. In ectomycorrhizal symbiosis up to 1/3 of plant photoassimilates could be transferred toward the fungal partner. The creation of such a strong sink is directly related to the efficiency of fungal hexose uptake at the plant/fungus interface, a modulated fungal carbohydrate metabolism in the ectomycorrhiza, and the export of carbohydrates towards soil growing hyphae. However, not only the fungus but also the plant partner increase its expression of hexose importer genes at the plant/fungus interface. This increase in hexose uptake capacity of plant roots in combination with an increase in photosynthesis may explain how the plant deals with the growing fungal carbohydrate demand in symbiosis and how it can restrict this loss of carbohydrates under certain conditions to avoid fungal parasitism. PMID:17078984

  1. Null mutation of chloride channel 7 (Clcn7) impairs dental root formation but does not affect enamel mineralization.

    PubMed

    Guo, Jing; Bervoets, Theodore J M; Henriksen, Kim; Everts, Vincent; Bronckers, Antonius L J J

    2016-02-01

    ClC-7, located in late endosomes and lysosomes, is critical for the function of osteoclasts. Secretion of Cl(-) by the ruffled border of osteoclasts enables H(+) secretion by v-H(+)-ATPases to dissolve bone mineral. Mice lacking ClC-7 show altered lysosomal function that leads to severe lysosomal storage. Maturation ameloblasts are epithelial cells with a ruffled border that secrete Cl(-) as well as endocytose and digest large quantities of enamel matrix proteins during formation of dental enamel. We tested the hypothesis that ClC-7 in maturation ameloblasts is required for intracellular digestion of matrix fragments to complete enamel mineralization. Craniofacial bones and developing teeth in Clcn7(-/-) mice were examined by micro-CT, immunohistochemistry, quantified histomorphometry and electron microscopy. Osteoclasts and ameloblasts in wild-type mice stained intensely with anti-ClC-7 antibody but not in Clcn7(-/-) mice. Craniofacial bones in Clcn7(-/-) mice were severely osteopetrotic and contained 1.4- to 1.6-fold more bone volume, which was less mineralized than the wild-type littermates. In Clcn7(-/-) mice maturation ameloblasts and osteoclasts highly expressed Ae2 as in wild-type mice. However, teeth failed to erupt, incisors were much shorter and roots were disfigured. Molars formed a normal dental crown. In compacted teeth, dentin was slightly less mineralized, enamel did not retain a matrix and mineralized fairly normal. We concluded that ClC-7 is essential for osteoclasts to resorb craniofacial bones to enable tooth eruption and root development. Disruption of Clcn7 reduces bone and dentin mineral density but does not affect enamel mineralization.

  2. Mutations in domain a′ of protein disulfide isomerase affect the folding pathway of bovine pancreatic ribonuclease A

    PubMed Central

    Ruoppolo, Margherita; Orrù, Stefania; Talamo, Fabio; Ljung, Johanna; Pirneskoski, Annamari; Kivirikko, Kari I.; Marino, Gennaro; Koivunen, Peppi

    2003-01-01

    Protein disulfide isomerase (PDI, EC 5.3.4.1), an enzyme and chaperone, catalyses disulfide bond formation and rearrangements in protein folding. It is also a subunit in two proteins, the enzyme collagen prolyl 4-hydroxylase and the microsomal triglyceride transfer protein. It consists of two catalytically active domains, a and a′, and two inactive ones, b and b′, all four domains having the thioredoxin fold. Domain b′ contains the primary peptide binding site, but a′ is also critical for several of the major PDI functions. Mass spectrometry was used here to follow the folding pathway of bovine pancreatic ribonuclease A (RNase A) in the presence of three PDI mutants, F449R, Δ455–457, and abb′, and the individual domains a and a′. The first two mutants contained alterations in the last α helix of domain a′, while the third lacked the entire domain a′. All mutants produced genuine, correctly folded RNase A, but the appearance rate of 50% of the product, as compared to wild-type PDI, was reduced 2.5-fold in the case of PDI Δ455–457, 7.5-fold to eightfold in the cases of PDI F449R and PDI abb′, and over 15-fold in the cases of the individual domains a and a′. In addition, PDI F449R and PDI abb′ affected the distribution of folding intermediates. Domains a and a′ catalyzed the early steps in the folding but no disulfide rearrangements, and therefore the rate observed in the presence of these individual domains was similar to that of the spontaneous process. PMID:12717017

  3. Deduced consensus sequence of Sindbis virus strain AR339: mutations contained in laboratory strains which affect cell culture and in vivo phenotypes.

    PubMed Central

    McKnight, K L; Simpson, D A; Lin, S C; Knott, T A; Polo, J M; Pence, D F; Johannsen, D B; Heidner, H W; Davis, N L; Johnston, R E

    1996-01-01

    The consensus sequence of the Sindbis virus AR339 isolate, the prototype alphavirus, has been deduced. THe results presented here suggest (i) that a substantial proportion of the sequence divergence evident between the consensus sequence and sequences of laboratory strains of AR339 has resulted from selection for efficient growth in cell culture, (ii) that many of these changes affect the virulence of the virus in animal models, and (iii) that such modified genetic backgrounds present in laboratory strains can exert a significant influence on genetic studies of virus pathogenesis and host range. A laboratory strain of Sindbis virus AR339 was sequenced and cloned as a cDNA (pTRSB) from which infectious virus (TRSB) could be derived. The consensus sequence was deduced from the complete sequences of pTRSB and HRsp (E. G. Strauss, C. M. Rice, and J. H. Strauss, Virology 133:92-110, 1984), from partial sequences of the glycoprotein genes of three other AR339 laboratory strains, and by comparison with the sequences of the glycoprotein genes of three other AR339 sequence. HRsp differed form the consensus sequence by eight coding changes, and TRSB differed by three coding changes. In the 5' untranslated region, HRsp differed from the consensus sequence at nucleotide (nt) 5. These differences were likely the result of cell culture passage of the original AR339 isolate. At three of the difference loci (one in TRSB and two in HRsp), selection of cell-culture-adaptive mutations was documented with Sindbis virus or other alphaviruses. Selection in cell culture often results in attenuation of virulence in animals. Considering the TRSB and HRsp sequences together, one noncoding difference from the consensus (an A-for-G substitution in the 5' untranslated region at nt 5) and six coding differences in the glycoprotein genes (at E2 amino acids 1, 3, 70, and 172 and at E1 amino acids 72 and 237) were at loci which, either individually or in combination, significantly affected

  4. A point mutation in the EGF-4 domain of β3 integrin is responsible for the formation of the Seca platelet alloantigen and affects receptor function

    PubMed Central

    Sachs, Ulrich J.; Bakchoul, Tamam; Eva, Olga; Giptner, Astrid; Bein, Gregor; Aster, Richard H.; Gitter, Maria; Peterson, Julie; Santoso, Sentot

    2013-01-01

    Summary Neonatal alloimmune thrombocytopenia (NAIT) is caused by fetomaternal platelet incompatibility with maternal antibodies crossing the placenta and destroying fetal platelets. Antibodies against human platelet antigen-1a (HPA-1a) and HPA-5b are responsible for the majority of NAIT cases. We observed a suspected NAIT in a newborn with a platelet count of 25 G/l and petechial haemorrhages. Serological analysis of maternal serum revealed an immunisation against αIIbβ3 on paternal platelets only, indicating the presence of an antibody against a new rare alloantigen (Seca) residing on αIIbβ3. The location of Seca on αIIbβ3 was confirmed by immunoprecipitation. Nucleotide sequence analysis of paternal β3 revealed a single nucleotide exchange (G1818T) in exon 11 of the β3 gene (ITGB3), changing Lys580 (wild-type) to Asn580 (Seca). Two additional members of the family Sec were typed Seca positive, but none of 300 blood donors. Chinese hamster ovary cells expressing Asn580, but not Lys580 αIIbβ3, bound anti-Seca, which was corroborated by immunoprecipitation. Adhesion of transfected cells onto immobilised fibrinogen showed reduced binding of the Asn580 variant compared to wild-type αIIbβ3. Analysis of transfected cells with anti-LIBS and PAC-1 antibody showed reduced binding when compared to the wild-type. No such effects were observed with Seca positive platelets, which, however, are heterozygous for the Lys580Asn mutation. In this study, we describe a NAIT case caused by maternal alloimmunisation against a new antigen on αIIbβ3. Analysis with mutant transfected cells showed that the Lys580Asn mutation responsible for the formation of the Seca antigenic determinant affects αIIbβ3 receptor function. PMID:22116617

  5. Genetic analysis of Rhizobium meliloti bacA-phoA fusion results in identification of degP: two loci required for symbiosis are closely linked to degP.

    PubMed Central

    Glazebrook, J; Ichige, A; Walker, G C

    1996-01-01

    The function of the Rhizobium meliloti bacA gene, which is a homolog of the Escherichia coli sbmA gene, is required for an intermediate step in nodule development. A strain carrying the bacA386::TnphoA fusion was mutagenized with N-methyl-N'-nitro-N-nitrosoguanidine, and three mutants that had higher levels of alkaline phosphatase activity were identified. The mutations in these strains were recessive and mapped to the same genetic locus. The gene affected by these mutations was identified and sequenced and was found to be a homolog of the E. coli degP gene, which encodes a periplasmic endopeptidase. Although degP function is important for the virulence of certain intracellular pathogens of mammals, it is not required for the R. meliloti-alfalfa symbiosis. The genetic analyses involving degP were complicated by the presence of a locus immediately upstream of depP that was lethal when present in multiple copies in a DegP- background. R. meliloti derivatives carrying insertion mutations in this locus displayed an N,N,N',N'-tetramethyl-p-phenylenediamine oxidase-negative phenotype, elicited the formation of white cylindrical nodules that did not fix nitrogen, and grew slowly in rich medium, suggesting that the locus was a cyc gene encoding a protein involved in the biosynthesis of a component or components of a respiratory chain. The previously identified fix-382::TnphoA, which similarly causes the formation of white cylindrical nodules that do not fix nitrogen, was shown to affect a gene that is separate from this cyc gene but extremely closely linked to it. PMID:8550509

  6. Arbuscular mycorrhizal symbiosis and active ingredients of medicinal plants: current research status and prospectives.

    PubMed

    Zeng, Yan; Guo, Lan-Ping; Chen, Bao-Dong; Hao, Zhi-Peng; Wang, Ji-Yong; Huang, Lu-Qi; Yang, Guang; Cui, Xiu-Ming; Yang, Li; Wu, Zhao-Xiang; Chen, Mei-Lan; Zhang, Yan

    2013-05-01

    Medicinal plants have been used world-wide for thousands of years and are widely recognized as having high healing but minor toxic side effects. The scarcity and increasing demand for medicinal plants and their products have promoted the development of artificial cultivation of medicinal plants. Currently, one of the prominent issues in medicinal cultivation systems is the unstable quality of the products. Arbuscular mycorrhiza (AM) affects secondary metabolism and the production of active ingredients of medicinal plants and thus influence the quality of herbal medicines. In this review, we have assembled, analyzed, and summarized the effects of AM symbioses on secondary metabolites of medicinal plants. We conclude that symbiosis of AM is conducive to favorable characteristics of medicinal plants, by improving the production and accumulation of important active ingredients of medicinal plants such as terpenes, phenols, and alkaloids, optimizing the composition of different active ingredients in medicinal plants and ultimately improving the quality of herbal materials. We are convinced that the AM symbiosis will benefit the cultivation of medicinal plants and improve the total yield and quality of herbal materials. Through this review, we hope to draw attention to the status and prospects of, and arouse more interest in, the research field of medicinal plants and mycorrhiza.

  7. Novel tools integrating metabolic and gene function to study the impact of the environment on coral symbiosis.

    PubMed

    Pernice, Mathieu; Levy, Oren

    2014-01-01

    The symbiotic dinoflagellates (genus Symbiodinium) inhabiting coral endodermal tissues are well known for their role as keystone symbiotic partners, providing corals with enormous amounts of energy acquired via photosynthesis and the absorption of dissolved nutrients. In the past few decades, corals reefs worldwide have been increasingly affected by coral bleaching (i.e., the breakdown of the symbiosis between corals and their dinoflagellate symbionts), which carries important socio-economic implications. Consequently, the number of studies focusing on the molecular and cellular processes underlying this biological phenomenon has grown rapidly, and symbiosis is now widely recognized as a major topic in coral biology. However, obtaining a clear image of the interplay between the environment and this mutualistic symbiosis remains challenging. Here, we review the potential of recent technological advances in molecular biology and approaches using stable isotopes to fill critical knowledge gaps regarding coral symbiotic function. Finally, we emphasize that the largest opportunity to achieve the full potential in this field arises from the integration of these technological advances.

  8. Tumor Infiltrating Lymphocytes Affect the Outcome of Patients with Operable Triple-Negative Breast Cancer in Combination with Mutated Amino Acid Classes

    PubMed Central

    Kotoula, Vassiliki; Lakis, Sotiris; Vlachos, Ioannis S.; Giannoulatou, Eleni; Zagouri, Flora; Alexopoulou, Zoi; Gogas, Helen; Pectasides, Dimitrios; Aravantinos, Gerasimos; Efstratiou, Ioannis; Pentheroudakis, George; Papadopoulou, Kyriaki; Chatzopoulos, Kyriakos; Papakostas, Pavlos; Sotiropoulou, Maria; Nicolaou, Irene; Razis, Evangelia; Psyrri, Amanda; Kosmidis, Paris; Papadimitriou, Christos; Fountzilas, George

    2016-01-01

    Background Stromal tumor infiltrating lymphocytes (TILs) density is an outcome predictor in triple-negative breast cancer (TNBC). Herein we asked whether TILs are related to coding mutation load and to the chemical class of the resulting mutated amino acids, i.e., charged, polar, and hydrophobic mutations. Methods We examined paraffin tumors from TNBC patients who had been treated with adjuvant chemotherapy mostly within clinical trials (training cohort, N = 133; validation, N = 190) for phenotype concordance; TILs density; mutation load and types. Results Concordance of TNBC phenotypes was 42.1% upon local / central, and 72% upon central / central pathology assessment. TILs were not associated with mutation load, type and class of mutated amino acids. Polar and charged mutation patterns differed between TP53 and PIK3CA (p<0.001). Hydrophobic mutations predicted for early relapse in patients with high nodal burden and <50% TILs tumors (training: HR 3.03, 95%CI 1.11–8.29, p = 0.031; validation: HR 2.90, 95%CI 0.97–8.70, p = 0.057), especially if compared to patients with >50% TILs tumors (training p = 0.003; validation p = 0.015). Conclusions TILs density is unrelated to mutation load in TNBC, which may be regarded as an unstable phenotype. If further validated, hydrophobic mutations along with TILs density may help identifying TNBC patients in higher risk for relapse. PMID:27685159

  9. Genes affected by mouse mammary tumor virus (MMTV) proviral insertions in mouse mammary tumors are deregulated or mutated in primary human mammary tumors

    PubMed Central

    Callahan, Robert; Mudunuri, Uma; Bargo, Sharon; Raafat, Ahmed; McCurdy, David; Boulanger, Corinne; Lowther, William; Stephens, Robert; Luke, Brian T.; Stewart, Claudia; Wu, Xiaolin; Munroe, David; Smith, Gilbert H.

    2012-01-01

    The accumulation of mutations is a contributing factor in the initiation of premalignant mammary lesions and their progression to malignancy and metastasis. We have used a mouse model in which the carcinogen is the mouse mammary tumor virus (MMTV) which induces clonal premalignant mammary lesions and malignant mammary tumors by insertional mutagenesis. Identification of the genes and signaling pathways affected in MMTV-induced mouse mammary lesions provides a rationale for determining whether genetic alteration of the human orthologues of these genes/pathways may contribute to human breast carcinogenesis. A high-throughput platform for inverse PCR to identify MMTV-host junction fragments and their nucleotide sequences in a large panel of MMTV-induced lesions was developed. Validation of the genes affected by MMTV-insertion was carried out by microarray analysis. Common integration site (CIS) means that the gene was altered by an MMTV proviral insertion in at least two independent lesions arising in different hosts. Three of the new genes identified as CIS for MMTV were assayed for their capability to confer on HC11 mouse mammary epithelial cells the ability for invasion, anchorage independent growth and tumor development in nude mice. Analysis of MMTV induced mammary premalignant hyperplastic outgrowth (HOG) lines and mammary tumors led to the identification of CIS restricted to 35 loci. Within these loci members of the Wnt, Fgf and Rspo gene families plus two linked genes (Npm3 and Ddn) were frequently activated in tumors induced by MMTV. A second group of 15 CIS occur at a low frequency (2-5 observations) in mammary HOGs or tumors. In this latter group the expression of either Phf19 or Sdc2 was shown to increase HC11 cells invasion capability. Foxl1 expression conferred on HC11 cells the capability for anchorage-independent colony formation in soft agar and tumor development in nude mice. The published transcriptome and nucleotide sequence analysis of gene

  10. A 2-component system is involved in the early stages of the Pisolithus tinctorius-Pinus greggii symbiosis.

    PubMed

    Herrera-Martínez, Aseneth; Ruiz-Medrano, Roberto; Galván-Gordillo, Santiago Valentín; Toscano Morales, Roberto; Gómez-Silva, Lidia; Valdés, María; Hinojosa-Moya, Jesús; Xoconostle-Cázares, Beatriz

    2014-01-01

    Ectomycorrhizal symbiosis results in profound morphological and physiological modifications in both plant and fungus. This in turn is the product of differential gene expression in both co-symbionts, giving rise to specialized cell types capable of performing novel functions. During the precolonization stage, chemical signals from root exudates are sensed by the ectomycorrizal fungus, and vice versa, which are in principle responsible for the observed change in the developmental symbionts program. Little is known about the molecular mechanisms involved in the signaling and recognition between ectomycorrhizal fungi and their host plants. In the present work, we characterized a novel lactone, termed pinelactone, and identified a gene encoding for a histidine kinase in Pisolithus tictorius, which function is proposed to be the perception of the aforementioned metabolites. In this study, the use of closantel, a specific inhibitor of histidine kinase phosphorylation, affected the capacity for fungal colonization in the symbiosis between Pisolithus tinctorius and Pinus greggii, indicating that a 2-component system (TCS) may operate in the early events of plant-fungus interaction. Indeed, the metabolites induced the accumulation of Pisolithus tinctorius mRNA for a putative histidine kinase (termed Pthik1). Of note, Pthik1 was able to partially complement a S. cerevisiae histidine kinase mutant, demonstrating its role in the response to the presence of the aforementioned metabolites. Our results indicate a role of a 2-component pathway in the early stages of ectomycorrhizal symbiosis before colonization. Furthermore, a novel lactone from Pinus greggii root exudates may activate a signal transduction pathway that contributes to the establishment of the ectomycorrhizal symbiosis.

  11. Synthetic enhancement of a TFIIB defect by a mutation in SSU72, an essential yeast gene encoding a novel protein that affects transcription start site selection in vivo.

    PubMed Central

    Sun, Z W; Hampsey, M

    1996-01-01

    An ssu72 mutant of Saccharomyces cerevisiae was identified as an enhancer of a TFIIB defect (sua7-1) that confers both a cold-sensitive growth defect and a downstream shift in transcription start site selection. The ssu72-1 allele did not affect cold sensitivity but, in combination with sua7-1, created a heat-sensitive phenotype. Moreover, start site selection at the ADH1 gene was dramatically shifted further downstream of the normal sites. Both of these effects could be rescued by either SUA7 or SSU72, thereby defining a functional relationship between the two genes. SSU72 is a single-copy, essential gene encoding a novel protein of 206 amino acids. The ssu72-1 allele is the result of a 30-bp duplication creating a sequence encoding a Cys-X2-Cys-X6-Cys-X2-Cys zinc binding motif near the N terminus of Ssu72p. Mutational analysis demonstrated that the N terminus of Ssu72p is essential for function and that cysteine residues in both the normal and mutant proteins are critical. We discuss the possibility that the potential zinc binding motif of Ssu72 facilitates assembly of the transcription preinitiation complex and that this effect is important for accurate start site selection in vivo. PMID:8657130

  12. Mutations of two transmembrane cysteines of hemagglutinin (HA) from influenza A H3N2 virus affect HA thermal stability and fusion activity.

    PubMed

    Xu, Shun; Zhou, Jianqiang; Liu, Kang; Liu, Qiliang; Xue, Chunyi; Li, Xiaoming; Zheng, Jing; Luo, Dongyu; Cao, Yongchang

    2013-08-01

    Influenza A H3N2 virus caused 1968 Hong Kong influenza pandemic, and has since been one of the most prevalent seasonal influenza viruses in global populations, representing a credible pandemic candidate in future. Previous studies have established that the hemagglutinin (HA) protein is the predominant antigen and executes receptor binding and membrane fusion. Homologous sequence analysis of all HA subtypes of influenza viruses revealed that two cysteine residues (540 and 544) are uniquely present in the transmembrane domain (TM) of HA proteins from all influenza A H3N2 viruses. However, the functions of these two cysteines have not been fully studied. Here, we generated three mutants (C540S, C544L, and 2C/SL) to investigate the effects of the two TM cysteines on the biological functions of H3 HA. We herein presented evidences that the mutations of one or two of the cysteines did not affect the proper expressions of HA proteins in cells, and more importantly all mutant H3 HAs showed decreased thermal stability but increased fusion activity in comparison with wildtype HA. Our results taken together demonstrated that the two TM cysteines are important for the biological functions of H3 HA proteins.

  13. Arsenic affects expression and processing of amyloid precursor protein (APP) in primary neuronal cells overexpressing the Swedish mutation of human APP.

    PubMed

    Zarazúa, Sergio; Bürger, Susanne; Delgado, Juan M; Jiménez-Capdeville, Maria E; Schliebs, Reinhard

    2011-06-01

    Arsenic poisoning due to contaminated water and soil, mining waste, glass manufacture, select agrochemicals, as well as sea food, affects millions of people world wide. Recently, an involvement of arsenic in Alzheimer's disease (AD) has been hypothesized (Gong and O'Bryant, 2010). The present study stresses the hypothesis whether sodium arsenite, and its main metabolite, dimethylarsinic acid (DMA), may affect expression and processing of the amyloid precursor protein (APP), using the cholinergic cell line SN56.B5.G4 and primary neuronal cells overexpressing the Swedish mutation of APP, as experimental approaches. Exposure of cholinergic SN56.B5.G4 cells with either sodium arsenite or DMA decreased cell viability in a concentration- and exposure-time dependent manner, and affected the activities of the cholinergic enzymes acetylcholinesterase and choline acetyltransferase. Both sodium arsenite and DMA exposure of SN56.B5.G4 cells resulted in enhanced level of APP, and sAPP in the membrane and cytosolic fractions, respectively. To reveal any effect of arsenic on APP processing, the amounts of APP cleavage products, sAPPβ, and β-amyloid (Aβ) peptides, released into the culture medium of primary neuronal cells derived from transgenic Tg2576 mice, were assessed by ELISA. Following exposure of neuronal cells by sodium arsenite for 12h, the membrane-bound APP level was enhanced, the amount of sAPPβ released into the culture medium was slightly higher, while the levels of Aβ peptides in the culture medium were considerably lower as compared to that assayed in the absence of any drug. The sodium arsenite-induced reduction of Aβ formation suggests an inhibition of the APP γ-cleavage step by arsenite. In contrast, DMA exposure of neuronal cells considerably increased formation of Aβ and sAPPβ, accompanied by enhanced membrane APP level. The DMA-induced changes in APP processing may be the result of the enhanced APP expression. Alternatively, increased Aβ production

  14. Differential Radiosensitivity Phenotypes of DNA-PKcs Mutations Affecting NHEJ and HRR Systems following Irradiation with Gamma-Rays or Very Low Fluences of Alpha Particles

    PubMed Central

    Little, John B.; Kato, Takamitsu A.; Shih, Hung-Ying; Xie, Xian-Jin; Wilson Jr., Paul F.; Brogan, John R.; Kurimasa, Akihiro; Chen, David J.; Bedford, Joel S.; Chen, Benjamin P. C.

    2014-01-01

    We have examined cell-cycle dependence of chromosomal aberration induction and cell killing after high or low dose-rate γ irradiation in cells bearing DNA-PKcs mutations in the S2056 cluster, the T2609 cluster, or the kinase domain. We also compared sister chromatid exchanges (SCE) production by very low fluences of α-particles in DNA-PKcs mutant cells, and in homologous recombination repair (HRR) mutant cells including Rad51C, Rad51D, and Fancg/xrcc9. Generally, chromosomal aberrations and cell killing by γ-rays were similarly affected by mutations in DNA-PKcs, and these mutant cells were more sensitive in G1 than in S/G2 phase. In G1-irradiated DNA-PKcs mutant cells, both chromosome- and chromatid-type breaks and exchanges were in excess than wild-type cells. For cells irradiated in late S/G2 phase, mutant cells showed very high yields of chromatid breaks compared to wild-type cells. Few exchanges were seen in DNA-PKcs-null, Ku80-null, or DNA-PKcs kinase dead mutants, but exchanges in excess were detected in the S2506 or T2609 cluster mutants. SCE induction by very low doses of α-particles is resulted from bystander effects in cells not traversed by α-particles. SCE seen in wild-type cells was completely abolished in Rad51C- or Rad51D-deficient cells, but near normal in Fancg/xrcc9 cells. In marked contrast, very high levels of SCEs were observed in DNA-PKcs-null, DNA-PKcs kinase-dead and Ku80-null mutants. SCE induction was also abolished in T2609 cluster mutant cells, but was only slightly reduced in the S2056 cluster mutant cells. Since both non-homologous end-joining (NHEJ) and HRR systems utilize initial DNA lesions as a substrate, these results suggest the possibility of a competitive interference phenomenon operating between NHEJ and at least the Rad51C/D components of HRR; the level of interaction between damaged DNA and a particular DNA-PK component may determine the level of interaction of such DNA with a relevant HRR component. PMID:24714417

  15. Differential radiosensitivity phenotypes of DNA-PKcs mutations affecting NHEJ and HRR systems following irradiation with gamma-rays or very low fluences of alpha particles.

    PubMed

    Lin, Yu-Fen; Nagasawa, Hatsumi; Little, John B; Kato, Takamitsu A; Shih, Hung-Ying; Xie, Xian-Jin; Wilson, Paul F; Brogan, John R; Kurimasa, Akihiro; Chen, David J; Bedford, Joel S; Chen, Benjamin P C

    2014-01-01

    We have examined cell-cycle dependence of chromosomal aberration induction and cell killing after high or low dose-rate γ irradiation in cells bearing DNA-PKcs mutations in the S2056 cluster, the T2609 cluster, or the kinase domain. We also compared sister chromatid exchanges (SCE) production by very low fluences of α-particles in DNA-PKcs mutant cells, and in homologous recombination repair (HRR) mutant cells including Rad51C, Rad51D, and Fancg/xrcc9. Generally, chromosomal aberrations and cell killing by γ-rays were similarly affected by mutations in DNA-PKcs, and these mutant cells were more sensitive in G1 than in S/G2 phase. In G1-irradiated DNA-PKcs mutant cells, both chromosome- and chromatid-type breaks and exchanges were in excess than wild-type cells. For cells irradiated in late S/G2 phase, mutant cells showed very high yields of chromatid breaks compared to wild-type cells. Few exchanges were seen in DNA-PKcs-null, Ku80-null, or DNA-PKcs kinase dead mutants, but exchanges in excess were detected in the S2506 or T2609 cluster mutants. SCE induction by very low doses of α-particles is resulted from bystander effects in cells not traversed by α-particles. SCE seen in wild-type cells was completely abolished in Rad51C- or Rad51D-deficient cells, but near normal in Fancg/xrcc9 cells. In marked contrast, very high levels of SCEs were observed in DNA-PKcs-null, DNA-PKcs kinase-dead and Ku80-null mutants. SCE induction was also abolished in T2609 cluster mutant cells, but was only slightly reduced in the S2056 cluster mutant cells. Since both non-homologous end-joining (NHEJ) and HRR systems utilize initial DNA lesions as a substrate, these results suggest the possibility of a competitive interference phenomenon operating between NHEJ and at least the Rad51C/D components of HRR; the level of interaction between damaged DNA and a particular DNA-PK component may determine the level of interaction of such DNA with a relevant HRR component.

  16. Missense and silent tau gene mutations cause frontotemporal dementia with parkinsonism-chromosome 17 type, by affecting multiple alternative RNA splicing regulatory elements.

    PubMed

    D'Souza, I; Poorkaj, P; Hong, M; Nochlin, D; Lee, V M; Bird, T D; Schellenberg, G D

    1999-05-11

    Frontotemporal dementia with parkinsonism, chromosome 17 type (FTDP-17) is caused by mutations in the tau gene, and the signature lesions of FTDP-17 are filamentous tau inclusions. Tau mutations may be pathogenic either by altering protein function or gene regulation. Here we show that missense, silent, and intronic tau mutations can increase or decrease splicing of tau exon 10 (E10) by acting on 3 different cis-acting regulatory elements. These elements include an exon splicing enhancer that can either be strengthened (mutation N279(K)) or destroyed (mutation Delta280(K)), resulting in either constitutive E10 inclusion or the exclusion of E10 from tau transcripts. E10 contains a second regulatory element that is an exon splicing silencer, the function of which is abolished by a silent FTDP-17 mutation (L284(L)), resulting in excess E10 inclusion. A third element inhibiting E10 splicing is contained in the intronic sequences directly flanking the 5' splice site of E10 and intronic FTDP-17 mutations in this element enhance E10 inclusion. Thus, tau mutations cause FTDP-17 by multiple pathological mechanisms, which may explain the phenotypic heterogeneity observed in FTDP-17, as exemplified by an unusual family described here with tau pathology as well as amyloid and neuritic plaques.

  17. General method for fine mapping of the Escherichia coli K-12 lamB gene: localization of missense mutations affecting bacteriophage lambda adsorption.

    PubMed Central

    Hofnung, M; Lepouce, E; Braun-Breton, C

    1981-01-01

    lamB is the structural gene for the bacteriophage lambda receptor, a multifunctional protein located in the outer membrane of Escherichia coli K-12. We present a method for deletion mapping of any lamB mutations with a recognizable pheno-type. This method involves a transducing phage constructed by in vitro recombination which can also be used for complementation, deoxyribonucleic acid sequence, and in vitro protein synthesis studies with the mutated lamB gene. Using this method, we mapped 18 lamB missense mutations which confer resistance to phage lambda h+ (wild-type host range). The main results were the following. (i) None of the 18 mutations was located in the first 4 deletion intervals out of the 11 of the genetic map. (ii) These mutations were clustered according to their phenotype as follows. (a) Class I mutations, which allow growth of lambda h and lambda hh* (one-step and two-step host range mutants of lambda, respectively), were located in three regions--three in interval V, four in interval VIII-IX, and three in interval X-XI. Only the last three mutations still allowed growth of phage K10 which also uses the lambda receptor, and two of them still allowed reversible binding of lambda h+. (b) All seven class II mutations allowed only growth of lambda hh* and mapped in interval V. These results are discussed in the frame of a genetic approach to the functional topology of the lambda receptor. PMID:6458595

  18. The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

    SciTech Connect

    Martin, F.; Aerts, A.; Ahren, D.; Brun, A.; Danchin, E. G. J.; Duchaussoy, F.; Gibon, J.; Kohler, A.; Lindquist, E.; Peresa, V.; Salamov, A.; Shapiro, H. J.; Wuyts, J.; Blaudez, D.; Buee, M.; Brokstein, P.; Canback, B.; Cohen, D.; Courty, P. E.; Coutinho, P. M.; Delaruelle, C.; Detter, J. C.; Deveau, A.; DiFazio, S.; Duplessis, S.; Fraissinet-Tachet, L.; Lucic, E.; Frey-Klett, P.; Fourrey, C.; Feussner, I.; Gay, G.; Grimwood, J.; Hoegger, P. J.; Jain, P.; Kilaru, S.; Labbe, J.; Lin, Y. C.; Legue, V.; Le Tacon, F.; Marmeisse, R.; Melayah, D.; Montanini, B.; Muratet, M.; Nehls, U.; Niculita-Hirzel, H.; Secq, M. P. Oudot-Le; Peter, M.; Quesneville, H.; Rajashekar, B.; Reich, M.; Rouhier, N.; Schmutz, J.; Yin, T.; Chalot, M.; Henrissat, B.; Kues, U.; Lucas, S.; Van de Peer, Y.; Podila, G. K.; Polle, A.; Pukkila, P. J.; Richardson, P. M.; Rouze, P.; Sanders, I. R.; Stajich, J. E.; Tunlid, A.; Tuskan, G.; Grigoriev, I. V.

    2007-08-10

    Mycorrhizal symbioses the union of roots and soil fungi are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants 1, 2. Boreal, temperate and montane forests all depend on ectomycorrhizae1. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are

  19. Coral Reef Genomics: Developing tools for functional genomics ofcoral symbiosis

    SciTech Connect

    Schwarz, Jodi; Brokstein, Peter; Manohar, Chitra; Coffroth, MaryAlice; Szmant, Alina; Medina, Monica

    2005-03-01

    Symbioses between cnidarians and dinoflagellates in the genus Symbiodinium are widespread in the marine environment. The importance of this symbiosis to reef-building corals and reef nutrient and carbon cycles is well documented, but little is known about the mechanisms by which the partners establish and regulate the symbiosis. Because the dinoflagellate symbionts live inside the cells of their host coral, the interactions between the partners occur on cellular and molecular levels, as each partner alters the expression of genes and proteins to facilitate the partnership. These interactions can examined using high-throughput techniques that allow thousands of genes to be examined simultaneously. We are developing the groundwork so that we can use DNA microarray profiling to identify genes involved in the Montastraea faveolata and Acropora palmata symbioses. Here we report results from the initial steps in this microarray initiative, that is, the construction of cDNA libraries from 4 of 16 target stages, sequencing of 3450 cDNA clones to generate Expressed Sequenced Tags (ESTs), and annotation of the ESTs to identify candidate genes to include in the microarrays. An understanding of how the coral-dinoflagellate symbiosis is regulated will have implications for atmospheric and ocean sciences, conservation biology, the study and diagnosis of coral bleaching and disease, and comparative studies of animal-protest interactions.

  20. Phosphorus and Nitrogen Regulate Arbuscular Mycorrhizal Symbiosis in Petunia hybrida

    PubMed Central

    Nouri, Eva; Breuillin-Sessoms, Florence; Feller, Urs; Reinhardt, Didier

    2014-01-01

    Phosphorus and nitrogen are essential nutrient elements that are needed by plants in large amounts. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. On the other hand, these nutrients influence root colonization by mycorrhizal fungi and symbiotic functioning. This represents a feedback mechanism that allows plants to control the fungal symbiont depending on nutrient requirements and supply. Elevated phosphorus supply has previously been shown to exert strong inhibition of arbuscular mycorrhizal development. Here, we address to what extent inhibition by phosphorus is influenced by other nutritional pathways in the interaction between Petunia hybrida and R. irregularis. We show that phosphorus and nitrogen are the major nutritional determinants of the interaction. Interestingly, the symbiosis-promoting effect of nitrogen starvation dominantly overruled the suppressive effect of high phosphorus nutrition onto arbuscular mycorrhiza, suggesting that plants promote the symbiosis as long as they are limited by one of the two major nutrients. Our results also show that in a given pair of symbiotic partners (Petunia hybrida and R. irregularis), the entire range from mutually symbiotic to parasitic can be observed depending on the nutritional conditions. Taken together, these results reveal complex nutritional feedback mechanisms in the control of root colonization by arbuscular mycorrhizal fungi. PMID:24608923

  1. Expression Islands Clustered on the Symbiosis Island of the Mesorhizobium loti Genome

    PubMed Central

    Uchiumi, Toshiki; Ohwada, Takuji; Itakura, Manabu; Mitsui, Hisayuki; Nukui, Noriyuki; Dawadi, Pramod; Kaneko, Takakazu; Tabata, Satoshi; Yokoyama, Tadashi; Tejima, Kouhei; Saeki, Kazuhiko; Omori, Hirofumi; Hayashi, Makoto; Maekawa, Takaki; Sriprang, Rutchadaporn; Murooka, Yoshikatsu; Tajima, Shigeyuki; Simomura, Kenshiro; Nomura, Mika; Suzuki, Akihiro; Shimoda, Yoshikazu; Sioya, Kouki; Abe, Mikiko; Minamisawa, Kiwamu

    2004-01-01

    Rhizobia are symbiotic nitrogen-fixing soil bacteria that are associated with host legumes. The establishment of rhizobial symbiosis requires signal exchanges between partners in microaerobic environments that result in mutualism for the two partners. We developed a macroarray for Mesorhizobium loti MAFF303099, a microsymbiont of the model legume Lotus japonicus, and monitored the transcriptional dynamics of the bacterium during symbiosis, microaerobiosis, and starvation. Global transcriptional profiling demonstrated that the clusters of genes within the symbiosis island (611 kb), a transmissible region distinct from other chromosomal regions, are collectively expressed during symbiosis, whereas genes outside the island are downregulated. This finding implies that the huge symbiosis island functions as clustered expression islands to support symbiotic nitrogen fixation. Interestingly, most transposase genes on the symbiosis island were highly upregulated in bacteroids, as were nif, fix, fdx, and rpoN. The genome region containing the fixNOPQ genes outside the symbiosis island was markedly upregulated as another expression island under both microaerobic and symbiotic conditions. The symbiosis profiling data suggested that there was activation of amino acid metabolism, as well as nif-fix gene expression. In contrast, genes for cell wall synthesis, cell division, DNA replication, and flagella were strongly repressed in differentiated bacteroids. A highly upregulated gene in bacteroids, mlr5932 (encoding 1-aminocyclopropane-1-carboxylate deaminase), was disrupted and was confirmed to be involved in nodulation enhancement, indicating that disruption of highly expressed genes is a useful strategy for exploring novel gene functions in symbiosis. PMID:15060047

  2. The EGFR mutation status affects the relative biological effectiveness of carbon-ion beams in non-small cell lung carcinoma cells.

    PubMed

    Amornwichet, Napapat; Oike, Takahiro; Shibata, Atsushi; Nirodi, Chaitanya S; Ogiwara, Hideaki; Makino, Haruhiko; Kimura, Yuka; Hirota, Yuka; Isono, Mayu; Yoshida, Yukari; Ohno, Tatsuya; Kohno, Takashi; Nakano, Takashi

    2015-06-11

    Carbon-ion radiotherapy (CIRT) holds promise to treat inoperable locally-advanced non-small cell lung carcinoma (NSCLC), a disease poorly controlled by standard chemoradiotherapy using X-rays. Since CIRT is an extremely limited medical resource, selection of NSCLC patients likely to benefit from it is important; however, biological predictors of response to CIRT are ill-defined. The present study investigated the association between the mutational status of EGFR and KRAS, driver genes frequently mutated in NSCLC, and the relative biological effectiveness (RBE) of carbon-ion beams over X-rays. The assessment of 15 NSCLC lines of different EGFR/KRAS mutational status and that of isogenic NSCLC lines expressing wild-type or mutant EGFR revealed that EGFR-mutant NSCLC cells, but not KRAS-mutant cells, show low RBE. This was attributable to (i) the high X-ray sensitivity of EGFR-mutant cells, since EGFR mutation is associated with a defect in non-homologous end joining, a major pathway for DNA double-strand break (DSB) repair, and (ii) the strong cell-killing effect of carbon-ion beams due to poor repair of carbon-ion beam-induced DSBs regardless of EGFR mutation status. These data highlight the potential of EGFR mutation status as a predictor of response to CIRT, i.e., CIRT may show a high therapeutic index in EGFR mutation-negative NSCLC.

  3. The p.A382T TARDBP gene mutation in Sardinian patients affected by Parkinson’s disease and other degenerative parkinsonisms

    PubMed Central

    Cannas, Antonino; Borghero, Giuseppe; Floris, Gian Luca; Solla, Paolo; Chiò, Adriano; Traynor, Bryan J.; Calvo, Andrea; Restagno, Gabriella; Majounie, Elisa; Costantino, Emanuela; Piras, Valeria; Lavra, Loredana; Pani, Carla; Orofino, Gianni; Di Stefano, Francesca; Tacconi, Paolo; Mascia, Marcello Mario; Muroni, Antonella; Murru, Maria Rita; Tranquilli, Stefania; Corongiu, Daniela; Rolesu, Marcella; Cuccu, Stefania; Marrosu, Francesco; Marrosu, Maria Giovanna

    2013-01-01

    Background Based on our previous finding of the p.A382T founder mutation in ALS patients with concomitant parkinsonism in the Sardinian population, we hypothesized that the same variant may underlie PD and/or other forms of degenerative parkinsonism on this Mediterranean island. Design We screened a cohort of 611 patients with PD (544 cases) and other forms of degenerative parkinsonism (67 cases), and 604 unrelated controls for the c.1144G>A (p.A382T) missense mutation of the TARDBP gene. Results The p.A382T mutation was identified in 9 patients with parkinsonism. Of these, 5 (0.9% of PD patients) presented a typical PD (2 with familiar forms), while 4 patients (6.0% of all other forms of parkinsonism) presented a peculiar clinical presentation quite different from classical atypical parkinsonism with an overlap of extrapyramidal-pyramidal-cognitive clinical signs. The mutation was found in 8 Sardinian controls (1.3%) consistent with a founder mutation in the island population. Conclusions Our findings suggest that the clinical presentation of the p.A382T TARDBP gene mutation may include forms of parkinsonism in which the extrapyramidal signs are the crucial core of the disease at onset. These forms can present PSP or CBD-like clinical signs, with bulbar and/or extrabulbar pyramidal signs and cognitive impairment. No evidence of association has been found between TARDBP gene mutation and typical PD. PMID:23546887

  4. The EGFR mutation status affects the relative biological effectiveness of carbon-ion beams in non-small cell lung carcinoma cells.

    PubMed

    Amornwichet, Napapat; Oike, Takahiro; Shibata, Atsushi; Nirodi, Chaitanya S; Ogiwara, Hideaki; Makino, Haruhiko; Kimura, Yuka; Hirota, Yuka; Isono, Mayu; Yoshida, Yukari; Ohno, Tatsuya; Kohno, Takashi; Nakano, Takashi

    2015-01-01

    Carbon-ion radiotherapy (CIRT) holds promise to treat inoperable locally-advanced non-small cell lung carcinoma (NSCLC), a disease poorly controlled by standard chemoradiotherapy using X-rays. Since CIRT is an extremely limited medical resource, selection of NSCLC patients likely to benefit from it is important; however, biological predictors of response to CIRT are ill-defined. The present study investigated the association between the mutational status of EGFR and KRAS, driver genes frequently mutated in NSCLC, and the relative biological effectiveness (RBE) of carbon-ion beams over X-rays. The assessment of 15 NSCLC lines of different EGFR/KRAS mutational status and that of isogenic NSCLC lines expressing wild-type or mutant EGFR revealed that EGFR-mutant NSCLC cells, but not KRAS-mutant cells, show low RBE. This was attributable to (i) the high X-ray sensitivity of EGFR-mutant cells, since EGFR mutation is associated with a defect in non-homologous end joining, a major pathway for DNA double-strand break (DSB) repair, and (ii) the strong cell-killing effect of carbon-ion beams due to poor repair of carbon-ion beam-induced DSBs regardless of EGFR mutation status. These data highlight the potential of EGFR mutation status as a predictor of response to CIRT, i.e., CIRT may show a high therapeutic index in EGFR mutation-negative NSCLC. PMID:26065573

  5. A mutation in the alpha 3 domain of Db that abrogates CD8 binding does not affect presentation of an immunodominant H-Y peptide.

    PubMed Central

    Dutz, J P; Teh, S J; Killeen, N; Teh, H S

    1995-01-01

    The peptidic nature of the male (H-Y) antigen, a model minor histocompatibility antigen in H-2b mice, has recently been demonstrated. In this study we show that the H-Y peptide, which is recognized by PM-1, a Db-restricted cytotoxic T-lymphocyte (CTL) clone, is absent in male H-2d spleen cells but present in male H-2d spleen cells that also express a transgenic Db molecule under its endogenous promoter. This result indicates that both the H-Y and the Db gene products are essential and sufficient for production of the Db-restricted H-Y peptide. By comparing the ability of the PM-1 clone and bulk CTL generated in a secondary mixed lymphocyte culture to recognize H-Y peptidic material eluted from affinity-purified Db molecules and separated by reversed-phase high-performance liquid chromatography (HPLC), we provide evidence that there is an immunodominant H-Y epitope that is presented by the Db molecule. Furthermore, the presentation of this epitope is not affected by a mutation in the alpha 3 domain of Db (asp227 to lys227), which abrogates CD8 binding, since similar amounts of H-Y peptide were eluted from affinity-purified wild-type or mutant Db molecules. However, the generation of the H-Y epitope is dependent on the presence of beta 2-microglobulin, since it is absent in male H-2b mice that lack a functional beta 2-microglobulin gene. The implications of these findings on T-cell development are discussed. PMID:7543449

  6. Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress.

    PubMed

    Porcel, Rosa; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique; Aroca, Ricardo; Garcia, Rosalva; Ruiz-Lozano, Juan Manuel

    2015-08-01

    Rice is the most important food crop in the world and is a primary source of food for more than half of the world population. However, salinity is considered the most common abiotic stress reducing its productivity. Soil salinity inhibits photosynthetic processes, which can induce an over-reduction of the reaction centres in photosystem II (PSII), damaging the photosynthetic machinery. The arbuscular mycorrhizal (AM) symbiosis may improve host plant tolerance to salinity, but it is not clear how the AM symbiosis affects the plant photosynthetic capacity, particularly the efficiency of PSII. This study aimed at determining the influence of the AM symbiosis on the performance of PSII in rice plants subjected to salinity. Photosynthetic activity, plant gas-exchange parameters, accumulation of photosynthetic pigments and rubisco activity and gene expression were also measured in order to analyse comprehensively the response of the photosynthetic processes to AM symbiosis and salinity. Results showed that the AM symbiosis enhanced the actual quantum yield of PSII photochemistry and reduced the quantum yield of non-photochemical quenching in rice plants subjected to salinity. AM rice plants maintained higher net photosynthetic rate, stomatal conductance and transpiration rate than nonAM plants. Thus, we propose that AM rice plants had a higher photochemical efficiency for CO2 fixation and solar energy utilization and this increases plant salt tolerance by preventing the injury to the photosystems reaction centres and by allowing a better utilization of light energy in photochemical processes. All these processes translated into higher photosynthetic and rubisco activities in AM rice plants and improved plant biomass production under salinity.

  7. Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress.

    PubMed

    Porcel, Rosa; Redondo-Gómez, Susana; Mateos-Naranjo, Enrique; Aroca, Ricardo; Garcia, Rosalva; Ruiz-Lozano, Juan Manuel

    2015-08-01

    Rice is the most important food crop in the world and is a primary source of food for more than half of the world population. However, salinity is considered the most common abiotic stress reducing its productivity. Soil salinity inhibits photosynthetic processes, which can induce an over-reduction of the reaction centres in photosystem II (PSII), damaging the photosynthetic machinery. The arbuscular mycorrhizal (AM) symbiosis may improve host plant tolerance to salinity, but it is not clear how the AM symbiosis affects the plant photosynthetic capacity, particularly the efficiency of PSII. This study aimed at determining the influence of the AM symbiosis on the performance of PSII in rice plants subjected to salinity. Photosynthetic activity, plant gas-exchange parameters, accumulation of photosynthetic pigments and rubisco activity and gene expression were also measured in order to analyse comprehensively the response of the photosynthetic processes to AM symbiosis and salinity. Results showed that the AM symbiosis enhanced the actual quantum yield of PSII photochemistry and reduced the quantum yield of non-photochemical quenching in rice plants subjected to salinity. AM rice plants maintained higher net photosynthetic rate, stomatal conductance and transpiration rate than nonAM plants. Thus, we propose that AM rice plants had a higher photochemical efficiency for CO2 fixation and solar energy utilization and this increases plant salt tolerance by preventing the injury to the photosystems reaction centres and by allowing a better utilization of light energy in photochemical processes. All these processes translated into higher photosynthetic and rubisco activities in AM rice plants and improved plant biomass production under salinity. PMID:26291919

  8. A novel mutation in the IRF6 gene associated with facial asymmetry in a family affected with Van der Woude syndrome.

    PubMed

    Miñones-Suárez, Lorena; Mas-Vidal, Alberto; Fernandez-Toral, Joaquin; Llano-Rivas, Isabel; González-García, Manuel

    2012-01-01

    This report describes a novel missense mutation in the interferon regulation factor 6 (IRF6) gene associated to facial asymmetry. This new feature widens the phenotype spectrum of Van der Woude syndrome (VWS). PMID:21995291

  9. IL36RN Mutations Affect Protein Expression and Function: A Basis for Genotype-Phenotype Correlation in Pustular Diseases.

    PubMed

    Tauber, Marie; Bal, Elodie; Pei, Xue-Yuan; Madrange, Marine; Khelil, Amel; Sahel, Houria; Zenati, Akila; Makrelouf, Mohamed; Boubridaa, Khaled; Chiali, Amel; Smahi, Naima; Otsmane, Farida; Bouajar, Bakar; Marrakchi, Slaheddine; Turki, Hamida; Bourrat, Emmanuelle; Viguier, Manuelle; Hamel, Yamina; Bachelez, Hervé; Smahi, Asma

    2016-09-01

    Homozygous or compound heterozygous IL36RN gene mutations underlie the pathogenesis of psoriasis-related pustular eruptions including generalized pustular psoriasis, palmoplantar pustular psoriasis, acrodermatitis continua of Hallopeau, and acute generalized exanthematous pustular eruption. We identified two unreported IL36RN homozygous mutations (c.41C>A/p.Ser14X and c.420_426del/p.Gly141MetfsX29) in patients with familial generalized pustular psoriasis. We analyzed the impact of a spectrum of IL36RN mutations on IL-36 receptor antagonist protein by using site-directed mutagenesis and expression in HEK293T cells. This enabled us to differentiate null mutations with complete absence of IL-36 receptor antagonist (the two previously unreported mutations, c.80T>C/p.Leu27Pro, c.28C>T/p.Arg10X, c.280G>T/p.Glu94X, c.368C>G/p.Thr123Arg, c.368C>T/p.Thr123Met, and c.227C>T/p.Pro76Leu) from mutations with decreased (c.95A>G/p.His32Arg, c.142C>T/p.Arg48Trp, and c.308C>T/p.Ser113Leu) or unchanged (c.304C>T/p.Arg102Trp and c.104A>G/p.Lys35Arg) protein expression. Functional assays measuring the impact of mutations on the capacity to repress IL-36-dependent activation of the NF-κB pathway showed complete functional impairment for null mutations, whereas partial or no impairment was observed for other mutations considered as hypomorphic. Finally, null mutations were associated with severe clinical phenotypes (generalized pustular psoriasis, acute generalized exanthematous pustular eruption), whereas hypomorphic mutations were identified in both localized (palmoplantar pustular psoriasis, acrodermatitis continua of Hallopeau) and generalized variants. These results provide a preliminary basis for genotype-phenotype correlation in patients with deficiency of the IL-36Ra (DITRA), and suggest the involvement of other factors in the modulation of clinical expression. PMID:27220475

  10. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems.

    PubMed

    Zigler, J Samuel; Hodgkinson, Colin A; Wright, Megan; Klise, Andrew; Sundin, Olof; Broman, Karl W; Hejtmancik, Fielding; Huang, Hao; Patek, Bonnie; Sergeev, Yuri; Hose, Stacey; Brayton, Cory; Xaiodong, Jiao; Vasquez, David; Maragakis, Nicholas; Mori, Susumu; Goldman, David; Hoke, Ahmet; Sinha, Debasish

    2016-01-01

    A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70-80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs

  11. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems

    PubMed Central

    Zigler, J. Samuel; Hodgkinson, Colin A.; Wright, Megan; Klise, Andrew; Broman, Karl W.; Huang, Hao; Patek, Bonnie; Sergeev, Yuri; Hose, Stacey; Xaiodong, Jiao; Vasquez, David; Maragakis, Nicholas; Mori, Susumu; Goldman, David; Sinha, Debasish

    2016-01-01

    A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70–80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs

  12. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems.

    PubMed

    Zigler, J Samuel; Hodgkinson, Colin A; Wright, Megan; Klise, Andrew; Sundin, Olof; Broman, Karl W; Hejtmancik, Fielding; Huang, Hao; Patek, Bonnie; Sergeev, Yuri; Hose, Stacey; Brayton, Cory; Xaiodong, Jiao; Vasquez, David; Maragakis, Nicholas; Mori, Susumu; Goldman, David; Hoke, Ahmet; Sinha, Debasish

    2016-01-01

    A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70-80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs.

  13. Modifications on the hydrogen bond network by mutations of Escherichia coli copper efflux oxidase affect the process of proton transfer to dioxygen leading to alterations of enzymatic activities

    SciTech Connect

    Kajikawa, Takao; Kataoka, Kunishige; Sakurai, Takeshi

    2012-05-25

    Highlights: Black-Right-Pointing-Pointer Proton transfer pathway to dioxygen in CueO was identified. Black-Right-Pointing-Pointer Glu506 is the key amino acid to transport proton. Black-Right-Pointing-Pointer The Ala mutation at Glu506 formed a compensatory proton transfer pathway. Black-Right-Pointing-Pointer The Ile mutation at Glu506 shut down the hydrogen bond network. -- Abstract: CueO has a branched hydrogen bond network leading from the exterior of the protein molecule to the trinuclear copper center. This network transports protons in the four-electron reduction of dioxygen. We replaced the acidic Glu506 and Asp507 residues with the charged and uncharged amino acid residues. Peculiar changes in the enzyme activity of the mutants relative to the native enzyme indicate that an acidic amino acid residue at position 506 is essential for effective proton transport. The Ala mutation resulted in the formation of a compensatory hydrogen bond network with one or two extra water molecules. On the other hand, the Ile mutation resulted in the complete shutdown of the hydrogen bond network leading to loss of enzymatic activities of CueO. In contrast, the hydrogen bond network without the proton transport function was constructed by the Gln mutation. These results exerted on the hydrogen bond network in CueO are discussed in comparison with proton transfers in cytochrome oxidase.

  14. The engine of the reef: photobiology of the coral-algal symbiosis.

    PubMed

    Roth, Melissa S

    2014-01-01

    Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology, and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral-algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral-algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral-algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral-algal symbiosis, and recent advances in the field. Studies integrating physiology with the developing "omics" fields will provide new insights into the coral-algal symbiosis. Greater physiological and ecological understanding of the coral-algal symbiosis is needed for protection and conservation of coral reefs.

  15. Impediment to symbiosis establishment between giant clams and Symbiodinium algae due to sterilization of seawater.

    PubMed

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment ("symbiosis rate") is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds.

  16. Man-Computer Symbiosis Through Interactive Graphics: A Survey and Identification of Critical Research Areas.

    ERIC Educational Resources Information Center

    Knoop, Patricia A.

    The purpose of this report was to determine the research areas that appear most critical to achieving man-computer symbiosis. An operational definition of man-computer symbiosis was developed by: (1) reviewing and summarizing what others have said about it, and (2) attempting to distinguish it from other types of man-computer relationships. From…

  17. Impediment to Symbiosis Establishment between Giant Clams and Symbiodinium Algae Due to Sterilization of Seawater

    PubMed Central

    Kurihara, Takeo; Yamada, Hideaki; Inoue, Ken; Iwai, Kenji; Hatta, Masayuki

    2013-01-01

    To survive the juvenile stage, giant clam juveniles need to establish a symbiotic relationship with the microalgae Symbiodinium occurring in the environment. The percentage of giant clam juveniles succeeding in symbiosis establishment (“symbiosis rate”) is often low, which is problematic for seed producers. We investigated how and why symbiosis rates vary, depending on whether giant clam seeds are continuously reared in UV treated or non treated seawater. Results repeatedly demonstrated that symbiosis rates were lower for UV treated seawater than for non treated seawater. Symbiosis rates were also lower for autoclaved seawater and 0.2-µm filtered seawater than for non treated seawater. The decreased symbiosis rates in various sterilized seawater suggest the possibility that some factors helping symbiosis establishment in natural seawater are weakened owing to sterilization. The possible factors include vitality of giant clam seeds, since additional experiments revealed that survival rates of seeds reared alone without Symbiodinium were lower in sterilized seawater than in non treated seawater. In conclusion, UV treatment of seawater was found to lead to decreased symbiosis rates, which is due possibly to some adverse effects common to the various sterilization techniques and relates to the vitality of the giant clam seeds. PMID:23613802

  18. Newly identified mutations at the CSN1S1 gene in Ethiopian goats affect casein content and coagulation properties of their milk.

    PubMed

    Mestawet, T A; Girma, A; Adnøy, T; Devold, T G; Vegarud, G E

    2013-08-01

    Very high casein content and good coagulation properties previously observed in some Ethiopian goat breeds led to investigating the αs1-casein (CSN1S1) gene in these breeds. Selected regions of the CSN1S1 gene were sequenced in 115 goats from 5 breeds (2 indigenous: Arsi-Bale and Somali, 1 exotic: Boer, and 2 crossbreeds: Boer × Arsi-Bale and Boer × Somali). The DNA analysis resulted in 35 new mutations: 3 in exons, 3 in the 5' untranslated region (UTR), and 29 in the introns. The mutations in exons that resulted in an amino acid shift were then picked to evaluate their influence on individual casein content (αs1-, αs2-, β-, and κ-CN), micellar size, and coagulation properties in the milk from the 5 goat breeds. A mutation at nucleotide 10657 (exon 10) involved a transversion: CAG→CCG, resulting in an amino acid exchange Gln77→Pro77. This mutation was associated with the indigenous breeds only. Two new mutations, at nucleotide 6072 (exon 4) and 12165 (exon 12), revealed synonymous transitions: GTC→GTT in Val15 and AGA→AGG in Arg100 of the mature protein. Transitions G→A and C→T at nucleotides 1374 and 1866, respectively, occurred in the 5' UTR, whereas the third mutation involved a transversion T→G at nucleotide location 1592. The goats were grouped into homozygote new (CC), homozygote reference (AA), and heterozygote (CA) based on the nucleotide that involved the transversion. The content of αs1-CN (15.32g/kg) in milk samples of goats homozygous (CC) for this newly identified mutation, Gln77→Pro77 was significantly higher than in milks of heterozygous (CA; 9.05g/kg) and reference (AA; 7.61g/kg) genotype animals. The αs2-, β-, and κ-CN contents showed a similar pattern. Milk from goats with a homozygous new mutation had significantly lower micellar size. Milk from both homozygote and heterozygote new-mutation goats had significantly shorter coagulation rate and stronger gel than the reference genotype. Except the transversion, the

  19. A novel mutation affecting the arginine-137 residue of AVPR2 in dizygous twins leads to nephrogenic diabetes insipidus and attenuated urine exosome aquaporin-2.

    PubMed

    Hinrichs, Gitte R; Hansen, Louise H; Nielsen, Maria R; Fagerberg, Christina; Dieperink, Hans; Rittig, Søren; Jensen, Boye L

    2016-04-01

    Mutations in the vasopressin V2 receptor gene AVPR2 may cause X-linked nephrogenic diabetes insipidus by defective apical insertion of aquaporin-2 in the renal collecting duct principal cell. Substitution mutations with exchange of arginine at codon 137 can cause nephrogenic syndrome of inappropriate antidiuresis or congenital X-linked nephrogenic diabetes insipidus. We present a novel mutation in codon 137 within AVPR2 with substitution of glycine for arginine in male dizygotic twins. Nephrogenic diabetes insipidus was demonstrated by water deprivation test and resistance to vasopressin administration. While a similar urine exosome release rate was shown between probands and controls by western blotting for the marker ALIX, there was a selective decrease in exosome aquaporin-2 versus aquaporin-1 protein in probands compared to controls. PMID:27117808

  20. Newly identified mutations at the CSN1S1 gene in Ethiopian goats affect casein content and coagulation properties of their milk.

    PubMed

    Mestawet, T A; Girma, A; Adnøy, T; Devold, T G; Vegarud, G E

    2013-08-01

    Very high casein content and good coagulation properties previously observed in some Ethiopian goat breeds led to investigating the αs1-casein (CSN1S1) gene in these breeds. Selected regions of the CSN1S1 gene were sequenced in 115 goats from 5 breeds (2 indigenous: Arsi-Bale and Somali, 1 exotic: Boer, and 2 crossbreeds: Boer × Arsi-Bale and Boer × Somali). The DNA analysis resulted in 35 new mutations: 3 in exons, 3 in the 5' untranslated region (UTR), and 29 in the introns. The mutations in exons that resulted in an amino acid shift were then picked to evaluate their influence on individual casein content (αs1-, αs2-, β-, and κ-CN), micellar size, and coagulation properties in the milk from the 5 goat breeds. A mutation at nucleotide 10657 (exon 10) involved a transversion: CAG→CCG, resulting in an amino acid exchange Gln77→Pro77. This mutation was associated with the indigenous breeds only. Two new mutations, at nucleotide 6072 (exon 4) and 12165 (exon 12), revealed synonymous transitions: GTC→GTT in Val15 and AGA→AGG in Arg100 of the mature protein. Transitions G→A and C→T at nucleotides 1374 and 1866, respectively, occurred in the 5' UTR, whereas the third mutation involved a transversion T→G at nucleotide location 1592. The goats were grouped into homozygote new (CC), homozygote reference (AA), and heterozygote (CA) based on the nucleotide that involved the transversion. The content of αs1-CN (15.32g/kg) in milk samples of goats homozygous (CC) for this newly identified mutation, Gln77→Pro77 was significantly higher than in milks of heterozygous (CA; 9.05g/kg) and reference (AA; 7.61g/kg) genotype animals. The αs2-, β-, and κ-CN contents showed a similar pattern. Milk from goats with a homozygous new mutation had significantly lower micellar size. Milk from both homozygote and heterozygote new-mutation goats had significantly shorter coagulation rate and stronger gel than the reference genotype. Except the transversion, the

  1. A novel mutation affecting the arginine-137 residue of AVPR2 in dizygous twins leads to nephrogenic diabetes insipidus and attenuated urine exosome aquaporin-2.

    PubMed

    Hinrichs, Gitte R; Hansen, Louise H; Nielsen, Maria R; Fagerberg, Christina; Dieperink, Hans; Rittig, Søren; Jensen, Boye L

    2016-04-01

    Mutations in the vasopressin V2 receptor gene AVPR2 may cause X-linked nephrogenic diabetes insipidus by defective apical insertion of aquaporin-2 in the renal collecting duct principal cell. Substitution mutations with exchange of arginine at codon 137 can cause nephrogenic syndrome of inappropriate antidiuresis or congenital X-linked nephrogenic diabetes insipidus. We present a novel mutation in codon 137 within AVPR2 with substitution of glycine for arginine in male dizygotic twins. Nephrogenic diabetes insipidus was demonstrated by water deprivation test and resistance to vasopressin administration. While a similar urine exosome release rate was shown between probands and controls by western blotting for the marker ALIX, there was a selective decrease in exosome aquaporin-2 versus aquaporin-1 protein in probands compared to controls.

  2. (Iron regulation of gene expression in the Bradyrhizobium japonicum/soybean symbiosis)

    SciTech Connect

    Guerinot, M.L.

    1992-01-01

    We wish to address the question of whether iron plays a regulatory role in the Bradyrhizobium japonicum/soybeam symbiosis. Iron may be an important regulatory signal in planta as the bacteria must acquire iron from their plant hosts and iron-containing proteins figure prominently in all nitrogen-fixing symbioses. For example, the bacterial partner is believed to synthesize the heme moiety of leghemoglobin, which may represent as much as 25--30% of the total soluble protein in an infected plant cell. For this reason, we have focused our attention on the regulation by iron of the first step in the bacterial heme biosynthetic pathway. The enzyme which catalyzes this step, 5-aminolevulinic acid synthase, is encoded by the hemA gene which we had previously cloned and sequenced. Specific objectives include: to define the cis-acting sequences which confer iron regulation on the B. japonicum hemA gene; to identify trans-acting factors which regulate the expression of hemA by iron; to identify new loci which are transcriptionally responsive to changes in iron availability; and to examine the effects of mutations in various known regulatory genes for their effect on the expression of hemA.

  3. [Iron regulation of gene expression in the Bradyrhizobium japonicum/soybean symbiosis]. Progress report

    SciTech Connect

    Guerinot, M.L.

    1992-06-01

    We wish to address the question of whether iron plays a regulatory role in the Bradyrhizobium japonicum/soybeam symbiosis. Iron may be an important regulatory signal in planta as the bacteria must acquire iron from their plant hosts and iron-containing proteins figure prominently in all nitrogen-fixing symbioses. For example, the bacterial partner is believed to synthesize the heme moiety of leghemoglobin, which may represent as much as 25--30% of the total soluble protein in an infected plant cell. For this reason, we have focused our attention on the regulation by iron of the first step in the bacterial heme biosynthetic pathway. The enzyme which catalyzes this step, 5-aminolevulinic acid synthase, is encoded by the hemA gene which we had previously cloned and sequenced. Specific objectives include: to define the cis-acting sequences which confer iron regulation on the B. japonicum hemA gene; to identify trans-acting factors which regulate the expression of hemA by iron; to identify new loci which are transcriptionally responsive to changes in iron availability; and to examine the effects of mutations in various known regulatory genes for their effect on the expression of hemA.

  4. Persistent virus and addiction modules: an engine of symbiosis.

    PubMed

    Villarreal, Luis P

    2016-06-01

    The giant DNA viruses are highly prevalent and have a particular affinity for the lytic infection of unicellular eukaryotic host. The giant viruses can also be infected by inhibitory virophage which can provide lysis protection to their host. The combined protective and destructive action of such viruses can define a general model (PD) of virus-mediated host survival. Here, I present a general model for role such viruses play in the evolution of host symbiosis. By considering how virus mixtures can participate in addiction modules, I provide a functional explanation for persistence of virus derived genetic 'junk' in their host genomic habitats. PMID:27039268

  5. Sustainable agriculture: possible trajectories from mutualistic symbiosis and plant neodomestication.

    PubMed

    Duhamel, Marie; Vandenkoornhuyse, Philippe

    2013-11-01

    Food demand will increase concomitantly with human population. Food production therefore needs to be high enough and, at the same time, minimize damage to the environment. This equation cannot be solved with current strategies. Based on recent findings, new trajectories for agriculture and plant breeding which take into account the belowground compartment and evolution of mutualistic strategy, are proposed in this opinion article. In this context, we argue that plant breeders have the opportunity to make use of native arbuscular mycorrhizal (AM) symbiosis in an innovative ecologically intensive agriculture.

  6. Stellar Pulsations and Stellar Evolution: Conflict, Cohabitation, or Symbiosis?

    NASA Astrophysics Data System (ADS)

    Weiss, Achim

    While the analysis of stellar pulsations allows the determination of current properties of a star, stellar evolution models connect it with its previous history. In many cases results from both methods do not agree. In this review some classical and current cases of disagreement are presented. In some cases these conflicts led to an improvement of the theory of stellar evolution, while in others they still remain unsolved. Some well-known problems of stellar physics are pointed out as well, for which it is hoped that seismology—or in general the analysis of stellar pulsations—will help to resolve them. The limits of this symbiosis will be discussed as well.

  7. Kidney adysplasia and variable hydronephrosis, a new mutation affecting the odd-skipped related 1 gene in the mouse, causes variable defects in kidney development and hydronephrosis

    PubMed Central

    Davisson, Muriel T.; Cook, Susan A.; Akeson, Ellen C.; Liu, Don; Heffner, Caleb; Gudis, Polyxeni; Fairfield, Heather

    2015-01-01

    Many genes, including odd-skipped related 1 (Osr1), are involved in regulation of mammalian kidney development. We describe here a new recessive mutation (kidney adysplasia and variable hydronephrosis, kavh) in the mouse that leads to downregulation of Osr1 transcript, causing several kidney defects: agenesis, hypoplasia, and hydronephrosis with variable age of onset. The mutation is closely associated with a reciprocal translocation, T(12;17)4Rk, whose Chromosome 12 breakpoint is upstream from Osr1. The kavh/kavh mutant provides a model to study kidney development and test therapies for hydronephrosis. PMID:25834070

  8. Kidney adysplasia and variable hydronephrosis, a new mutation affecting the odd-skipped related 1 gene in the mouse, causes variable defects in kidney development and hydronephrosis.

    PubMed

    Davisson, Muriel T; Cook, Susan A; Akeson, Ellen C; Liu, Don; Heffner, Caleb; Gudis, Polyxeni; Fairfield, Heather; Murray, Stephen A

    2015-06-15

    Many genes, including odd-skipped related 1 (Osr1), are involved in regulation of mammalian kidney development. We describe here a new recessive mutation (kidney adysplasia and variable hydronephrosis, kavh) in the mouse that leads to downregulation of Osr1 transcript, causing several kidney defects: agenesis, hypoplasia, and hydronephrosis with variable age of onset. The mutation is closely associated with a reciprocal translocation, T(12;17)4Rk, whose Chromosome 12 breakpoint is upstream from Osr1. The kavh/kavh mutant provides a model to study kidney development and test therapies for hydronephrosis.

  9. Mutational spectrum drives the rise of mutator bacteria.

    PubMed

    Couce, Alejandro; Guelfo, Javier R; Blázquez, Jesús

    2013-01-01

    Understanding how mutator strains emerge in bacterial populations is relevant both to evolutionary theory and to reduce the threat they pose in clinical settings. The rise of mutator alleles is understood as a result of their hitchhiking with linked beneficial mutations, although the factors that govern this process remain unclear. A prominent but underappreciated fact is that each mutator allele increases only a specific spectrum of mutational changes. This spectrum has been speculated to alter the distribution of fitness effects of beneficial mutations, potentially affecting hitchhiking. To study this possibility, we analyzed the fitness distribution of beneficial mutations generated from different mutator and wild-type Escherichia coli strains. Using antibiotic resistance as a model system, we show that mutational spectra can alter these distributions substantially, ultimately determining the competitive ability of each strain across environments. Computer simulation showed that the effect of mutational spectrum on hitchhiking dynamics follows a non-linear function, implying that even slight spectrum-dependent fitness differences are sufficient to alter mutator success frequency by several orders of magnitude. These results indicate an unanticipated central role for the mutational spectrum in the evolution of bacterial mutation rates. At a practical level, this study indicates that knowledge of the molecular details of resistance determinants is crucial for minimizing mutator evolution during antibiotic therapy.

  10. A Missense Mutation in CLIC2 Associated with Intellectual Disability is Predicted by In Silico Modeling to Affect Protein Stability and Dynamics

    PubMed Central

    Witham, Shawn; Takano, Kyoko; Schwartz, Charles; Alexov, Emil

    2011-01-01

    Large-scale next generation resequencing of X chromosome genes identified a missense mutation in the CLIC2 gene on Xq28 in a male with X-linked intellectual disability (XLID) and not found in healthy individuals. At the same time, numerous nsSNPs (nonsynonomous SNP) have been reported in the CLIC2 gene in healthy individuals indicating that the CLIC2 protein can tolerate amino acid substitutions and be fully functional. To test the possibility that p.H101Q is a disease-causing mutation, we performed in silico simulations to calculate the effects of the p.H101Q mutation on CLIC2 stability, dynamics and ionization states while comparing the effects obtained for presumably harmless nsSNPs. It was found that p.H101Q, in contrast with other nsSNPs, (a) lessens the flexibility of the joint loop which is important for the normal function of CLIC2, (b) makes the overall 3D structure of CLIC2 more stable and thus reduces the possibility of the large conformational change expected to occur when CLIC2 moves from a soluble to membrane form and (c) removes the positively charged residue, H101, which may be important for the membrane association of CLIC2. The results of in silico modeling, in conjunction with the polymorphism analysis, suggest that p.H101Q may be a disease-causing mutation, the first one suggested in the CLIC family. PMID:21630357

  11. Effects of multiple climate change factors on the tall fescue-fungal endophyte symbiosis: infection frequency and tissue chemistry.

    SciTech Connect

    Brosi, Glade; McCulley, Rebecca L; Bush, L P; Nelson, Jim A; Classen, Aimee T; Norby, Richard J

    2011-01-01

    Climate change (altered CO{sub 2}, warming, and precipitation) may affect plant-microbial interactions, such as the Lolium arundinaceum-Neotyphodium coenophialum symbiosis, to alter future ecosystem structure and function. To assess this possibility, tall fescue tillers were collected from an existing climate manipulation experiment in a constructed old-field community in Tennessee (USA). Endophyte infection frequency (EIF) was determined, and infected (E+) and uninfected (E-) tillers were analysed for tissue chemistry. The EIF of tall fescue was higher under elevated CO{sub 2} (91% infected) than with ambient CO{sub 2} (81%) but was not affected by warming or precipitation treatments. Within E+ tillers, elevated CO{sub 2} decreased alkaloid concentrations of both ergovaline and loline, by c. 30%; whereas warming increased loline concentrations 28% but had no effect on ergovaline. Independent of endophyte infection, elevated CO{sub 2} reduced concentrations of nitrogen, cellulose, hemicellulose, and lignin. These results suggest that elevated CO{sub 2}, more than changes in temperature or precipitation, may promote this grass-fungal symbiosis, leading to higher EIF in tall fescue in old-field communities. However, as all three climate factors are likely to change in the future, predicting the symbiotic response and resulting ecological consequences may be difficult and dependent on the specific atmospheric and climatic conditions encountered.

  12. The symbiont side of symbiosis: do microbes really benefit?

    PubMed Central

    Garcia, Justine R.; Gerardo, Nicole M.

    2014-01-01

    Microbial associations are integral to all eukaryotes. Mutualism, the interaction of two species for the benefit of both, is an important aspect of microbial associations, with evidence that multicellular organisms in particular benefit from microbes. However, the microbe’s perspective has largely been ignored, and it is unknown whether most microbial symbionts benefit from their associations with hosts. It has been presumed that microbial symbionts receive host-derived nutrients or a competition-free environment with reduced predation, but there have been few empirical tests, or even critical assessments, of these assumptions. We evaluate these hypotheses based on available evidence, which indicate reduced competition and predation are not universal benefits for symbionts. Some symbionts do receive nutrients from their host, but this has not always been linked to a corresponding increase in symbiont fitness. We recommend experiments to test symbiont fitness using current experimental systems of symbiosis and detail considerations for other systems. Incorporating symbiont fitness into symbiosis research will provide insight into the evolution of mutualistic interactions and cooperation in general. PMID:25309530

  13. Understanding resilience in industrial symbiosis networks: insights from network analysis.

    PubMed

    Chopra, Shauhrat S; Khanna, Vikas

    2014-08-01

    Industrial symbiotic networks are based on the principles of ecological systems where waste equals food, to develop synergistic networks. For example, industrial symbiosis (IS) at Kalundborg, Denmark, creates an exchange network of waste, water, and energy among companies based on contractual dependency. Since most of the industrial symbiotic networks are based on ad-hoc opportunities rather than strategic planning, gaining insight into disruptive scenarios is pivotal for understanding the balance of resilience and sustainability and developing heuristics for designing resilient IS networks. The present work focuses on understanding resilience as an emergent property of an IS network via a network-based approach with application to the Kalundborg Industrial Symbiosis (KIS). Results from network metrics and simulated disruptive scenarios reveal Asnaes power plant as the most critical node in the system. We also observe a decrease in the vulnerability of nodes and reduction in single points of failure in the system, suggesting an increase in the overall resilience of the KIS system from 1960 to 2010. Based on our findings, we recommend design strategies, such as increasing diversity, redundancy, and multi-functionality to ensure flexibility and plasticity, to develop resilient and sustainable industrial symbiotic networks.

  14. Genes conserved for arbuscular mycorrhizal symbiosis identified through phylogenomics.

    PubMed

    Bravo, Armando; York, Thomas; Pumplin, Nathan; Mueller, Lukas A; Harrison, Maria J

    2016-01-01

    Arbuscular mycorrhizal symbiosis (AMS), a widespread mutualistic association of land plants and fungi(1), is predicted to have arisen once, early in the evolution of land plants(2-4). Consistent with this notion, several genes required for AMS have been conserved throughout evolution(5) and their symbiotic functions preserved, at least between monocot and dicot plants(6,7). Despite its significance, knowledge of the plants' genetic programme for AMS is limited. To date, most genes required for AMS have been found through commonalities with the evolutionarily younger nitrogen-fixing Rhizobium legume symbiosis (RLS)(8) or by reverse genetic analyses of differentially expressed candidate genes(9). Large sequence-indexed insertion mutant collections and recent genome editing technologies have vastly increased the power of reverse genetics but selection of candidate genes, from the thousands of genes that change expression during AMS, remains an arbitrary process. Here, we describe a phylogenomics approach to identify genes whose evolutionary history predicts conservation for AMS and we demonstrate the accuracy of the predictions through reverse genetics analysis. Phylogenomics analysis of 50 plant genomes resulted in 138 genes from Medicago truncatula predicted to function in AMS. This includes 15 genes with known roles in AMS. Additionally, we demonstrate that mutants in six previously uncharacterized AMS-conserved genes are all impaired in AMS. Our results demonstrate that phylogenomics is an effective strategy to identify a set of evolutionarily conserved genes required for AMS. PMID:27249190

  15. An ancient tripartite symbiosis of plants, ants and scale insects.

    PubMed

    Ueda, Shouhei; Quek, Swee-Peck; Itioka, Takao; Inamori, Keita; Sato, Yumiko; Murase, Kaori; Itino, Takao

    2008-10-22

    In the Asian tropics, a conspicuous radiation of Macaranga plants is inhabited by obligately associated Crematogaster ants tending Coccus (Coccidae) scale insects, forming a tripartite symbiosis. Recent phylogenetic studies have shown that the plants and the ants have been codiversifying over the past 16-20 million years (Myr). The prevalence of coccoids in ant-plant mutualisms suggest that they play an important role in the evolution of ant-plant symbioses. To determine whether the scale insects were involved in the evolutionary origin of the mutualism between Macaranga and Crematogaster, we constructed a cytochrome oxidase I (COI) gene phylogeny of the scale insects collected from myrmecophytic Macaranga and estimated their time of origin based on a COI molecular clock. The minimum age of the associated Coccus was estimated to be half that of the ants, at 7-9Myr, suggesting that they were latecomers in the evolutionary history of the symbiosis. Crematogaster mitochondrial DNA (mtDNA) lineages did not exhibit specificity towards Coccus mtDNA lineages, and the latter was not found to be specific towards Macaranga taxa, suggesting that patterns of associations in the scale insects are dictated by opportunity rather than by specialized adaptations to host plant traits.

  16. Arsenic effect on the model crop symbiosis Bradyrhizobium-soybean.

    PubMed

    Talano, Melina A; Cejas, Romina B; González, Paola S; Agostini, Elizabeth

    2013-02-01

    Soybean (Glycine max) is often being cultivated in soils with moderate to high arsenic (As) concentrations or under irrigation with As contaminated groundwater. The purpose of this study was to determine the effect of As on soybean germination, development and nodulation in soybean-Bradyrhizobium japonicum E109 symbiosis, as a first-step approach to evaluate the impact of As on soybean production. Semi-hydroponic assays were conducted using soybean seedlings inoculated and non-inoculated with B. japonicum E109 and treated with arsenate or arsenite. Soybean germination and development, at early stage of growth, were significantly reduced from 10 μM arsenate or arsenite. This also was seen for soybean seedlings inoculated with B. japonicum mainly with arsenite where, in addition, the number of effective nodules was reduced, despite that the microorganism tolerated the metalloid. This minor nodulation could be due to a reduced motility (swarming and swimming) of the microorganism in presence of As. Arsenic concentration in roots was about 250-times higher than in shoots. Transference coefficient values indicated that As translocation to aerial parts was low and As accumulated mainly in roots, without significant differences between inoculated and non-inoculated plants. The presence of As restricted soybean-B. japonicum symbiosis and hence, the efficiency of most used commercial inoculants for soybean. Thus, water and/or soils containing As would negatively impact on soybean production, even in plants inoculated with B. japonicum E109.

  17. Aphids evolved novel secreted proteins for symbiosis with bacterial endosymbiont.

    PubMed

    Shigenobu, Shuji; Stern, David L

    2013-01-01

    Aphids evolved novel cells, called bacteriocytes, that differentiate specifically to harbour the obligatory mutualistic endosymbiotic bacteria Buchnera aphidicola. The genome of the host aphid Acyrthosiphon pisum contains many orphan genes that display no similarity with genes found in other sequenced organisms, prompting us to hypothesize that some of these orphan genes are related to lineage-specific traits, such as symbiosis. We conducted deep sequencing of bacteriocytes mRNA followed by whole mount in situ hybridizations of over-represented transcripts encoding aphid-specific orphan proteins. We identified a novel class of genes that encode small proteins with signal peptides, which are often cysteine-rich, that are over-represented in bacteriocytes. These genes are first expressed at a developmental time point coincident with the incorporation of symbionts strictly in the cells that contribute to the bacteriocyte and this bacteriocyte-specific expression is maintained throughout the aphid's life. The expression pattern suggests that recently evolved secretion proteins act within bacteriocytes, perhaps to mediate the symbiosis with beneficial bacterial partners, which is reminiscent of the evolution of novel cysteine-rich secreted proteins of leguminous plants that regulate nitrogen-fixing endosymbionts.

  18. ida4-1, ida4-2, and ida4-3 are intron splicing mutations affecting the locus encoding p28, a light chain of Chlamydomonas axonemal inner dynein arms.

    PubMed Central

    LeDizet, M; Piperno, G

    1995-01-01

    We recently determined the nucleotide sequence of the gene encoding p28, a light chain of inner dynein arms of Chlamydomonas axonemes. Here, we show that p28 is the protein encoded by the IDA4 locus. p28, and the dynein heavy chains normally associated with it, are completely absent from the flagella and cell bodies of three allelic strains of ida4, named ida4-1, ida4-2, and ida4-3. We determined the nucleotide sequence of the three alleles of the p28 gene and found in each case a single nucleotide change, affecting the splice sites of the first, second, and fourth introns, respectively. Reverse transcriptase-polymerase chain reaction amplification of RNAs prepared from ida4 cells confirmed that these mutations prevent the correct splicing of the affected introns, thereby blocking the synthesis of full-length p28. These are the first intron splicing mutations described in Chlamydomonas and the first inner dynein arm mutations characterized at the molecular level. The absence in ida4 axonemes of the dynein heavy chains normally found in association with p28 suggests that p28 is necessary for stable assembly of a subset of inner dynein arms or for the binding of these arms to the microtubule doublets. Images PMID:7579690

  19. Do mutator mutations fuel tumorigenesis?

    PubMed

    Fox, Edward J; Prindle, Marc J; Loeb, Lawrence A

    2013-12-01

    The mutator phenotype hypothesis proposes that the mutation rate of normal cells is insufficient to account for the large number of mutations found in human cancers. Consequently, human tumors exhibit an elevated mutation rate that increases the likelihood of a tumor acquiring advantageous mutations. The hypothesis predicts that tumors are composed of cells harboring hundreds of thousands of mutations, as opposed to a small number of specific driver mutations, and that malignant cells within a tumor therefore constitute a highly heterogeneous population. As a result, drugs targeting specific mutated driver genes or even pathways of mutated driver genes will have only limited anticancer potential. In addition, because the tumor is composed of such a diverse cell population, tumor cells harboring drug-resistant mutations will exist prior to the administration of any chemotherapeutic agent. We present recent evidence in support of the mutator phenotype hypothesis, major arguments against this concept, and discuss the clinical consequences of tumor evolution fueled by an elevated mutation rate. We also consider the therapeutic possibility of altering the rate of mutation accumulation. Most significantly, we contend that there is a need to fundamentally reconsider current approaches to personalized cancer therapy. We propose that targeting cellular pathways that alter the rate of mutation accumulation in tumors will ultimately prove more effective than attempting to identify and target mutant driver genes or driver pathways.

  20. The two mutations, Q204X and nt821, of the myostatin gene affect carcass and meat quality in young heterozygous bulls of French beef breeds.

    PubMed

    Allais, S; Levéziel, H; Payet-Duprat, N; Hocquette, J F; Lepetit, J; Rousset, S; Denoyelle, C; Bernard-Capel, C; Journaux, L; Bonnot, A; Renand, G

    2010-02-01

    The availability of genetic tests to detect different mutations in the myostatin gene allows the identification of heterozygous animals and would warrant the superiority of these animals for slaughter performance if this superiority is confirmed. Thus, 2 mutations of this gene, Q204X and nt821, were studied in 3 French beef breeds in the program Qualvigène. This work was done with 1,114 Charolais, 1,254 Limousin, and 981 Blonde d'Aquitaine young bulls from, respectively, 48, 36, and 30 sires and slaughtered from 2004 to 2006. In addition to the usual carcass traits recorded at slaughter (e.g., carcass yield, muscle score), carcass composition was estimated by weighing internal fat and dissecting the 6th rib. The muscle characteristic traits analyzed were lipid and collagen contents, muscle fiber section area, and pH. Regarding meat quality, sensory qualities of meat samples were evaluated by a taste panel, and Warner-Bratzler shear force was measured. Deoxyribonucleic acid was extracted from the blood samples of all calves, the blood samples of 78% of the dams, and the blood or semen samples of all the sires. Genotypes were determined for 2 disruptive mutations, Q204X and nt821. Analyses were conducted by breed. The superiority of carcass traits of calves carrying one copy of the mutated allele (Q204X or nt821) over noncarrier animals was approximately +1 SD in the Charolais and Limousin breeds but was not significant in the Blonde d'Aquitaine. In the Charolais breed, for which the frequency was the greatest (7%), young bulls carrying the Q204X mutation presented a carcass with less fat, less intramuscular fat and collagen contents, and a clearer and more tender meat than those of homozygous-normal cattle. The meat of these animals also had slightly less flavor. Also in the Charolais breed, 13 of 48 sires were heterozygous. For each sire, the substitution effect of the wild allele by the mutant allele was approximately +1 SD for carcass conformation and yield

  1. A nonsense mutation in mouse Tardbp affects TDP43 alternative splicing activity and causes limb-clasping and body tone defects.

    PubMed

    Ricketts, Thomas; McGoldrick, Philip; Fratta, Pietro; de Oliveira, Hugo M; Kent, Rosie; Phatak, Vinaya; Brandner, Sebastian; Blanco, Gonzalo; Greensmith, Linda; Acevedo-Arozena, Abraham; Fisher, Elizabeth M C

    2014-01-01

    Mutations in TARDBP, encoding Tar DNA binding protein-43 (TDP43), cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Attempts to model TDP43 dysfunction in mice have used knockouts or transgenic overexpressors, which have revealed the difficulties of manipulating TDP43, whose level is tightly controlled by auto-regulation. In a complementary approach, to create useful mouse models for the dissection of TDP43 function and pathology, we have identified a nonsense mutation in the endogenous mouse Tardbp gene through screening an N-ethyl-N-nitrosourea (ENU) mutant mouse archive. The mutation is predicted to cause a Q101X truncation in TDP43. We have characterised Tardbp(Q101X) mice to investigate this mutation in perturbing TDP43 biology at endogenous expression levels. We found the Tardbp(Q101X) mutation is homozygous embryonic lethal, highlighting the importance of TDP43 in early development. Heterozygotes (Tardbp(+/Q101X) ) have abnormal levels of mutant transcript, but we find no evidence of the truncated protein and mice have similar full-length TDP43 protein levels as wildtype littermates. Nevertheless, Tardbp(+/Q101X) mice have abnormal alternative splicing of downstream gene targets, and limb-clasp and body tone phenotypes. Thus the nonsense mutation in Tardbp causes a mild loss-of-function phenotype and behavioural assessment suggests underlying neurological abnormalities. Due to the role of TDP43 in ALS, we investigated potential interactions with another known causative gene, mutant superoxide dismutase 1 (SOD1). Tardbp(+/Q101X) mice were crossed with the SOD1(G93Adl) transgenic mouse model of ALS. Behavioural and physiological assessment did not reveal modifying effects on the progression of ALS-like symptoms in the double mutant progeny from this cross. In summary, the Tardbp(Q101X) mutant mice are a useful tool for the dissection of TDP43 protein regulation, effects on splicing, embryonic development and neuromuscular phenotypes

  2. The two mutations, Q204X and nt821, of the myostatin gene affect carcass and meat quality in young heterozygous bulls of French beef breeds.

    PubMed

    Allais, S; Levéziel, H; Payet-Duprat, N; Hocquette, J F; Lepetit, J; Rousset, S; Denoyelle, C; Bernard-Capel, C; Journaux, L; Bonnot, A; Renand, G

    2010-02-01

    The availability of genetic tests to detect different mutations in the myostatin gene allows the identification of heterozygous animals and would warrant the superiority of these animals for slaughter performance if this superiority is confirmed. Thus, 2 mutations of this gene, Q204X and nt821, were studied in 3 French beef breeds in the program Qualvigène. This work was done with 1,114 Charolais, 1,254 Limousin, and 981 Blonde d'Aquitaine young bulls from, respectively, 48, 36, and 30 sires and slaughtered from 2004 to 2006. In addition to the usual carcass traits recorded at slaughter (e.g., carcass yield, muscle score), carcass composition was estimated by weighing internal fat and dissecting the 6th rib. The muscle characteristic traits analyzed were lipid and collagen contents, muscle fiber section area, and pH. Regarding meat quality, sensory qualities of meat samples were evaluated by a taste panel, and Warner-Bratzler shear force was measured. Deoxyribonucleic acid was extracted from the blood samples of all calves, the blood samples of 78% of the dams, and the blood or semen samples of all the sires. Genotypes were determined for 2 disruptive mutations, Q204X and nt821. Analyses were conducted by breed. The superiority of carcass traits of calves carrying one copy of the mutated allele (Q204X or nt821) over noncarrier animals was approximately +1 SD in the Charolais and Limousin breeds but was not significant in the Blonde d'Aquitaine. In the Charolais breed, for which the frequency was the greatest (7%), young bulls carrying the Q204X mutation presented a carcass with less fat, less intramuscular fat and collagen contents, and a clearer and more tender meat than those of homozygous-normal cattle. The meat of these animals also had slightly less flavor. Also in the Charolais breed, 13 of 48 sires were heterozygous. For each sire, the substitution effect of the wild allele by the mutant allele was approximately +1 SD for carcass conformation and yield

  3. Genotype/phenotype correlations of males affected by Simpson-Golabi-Behmel syndrome with GPC3 gene mutations: patient report and review of the literature.

    PubMed

    Mariani, Sabrina; Iughetti, Lorenzo; Bertorelli, Roberto; Coviello, Domenico; Pellegrini, Massimo; Forabosco, Antonino; Bernasconi, Sergio

    2003-02-01

    Simpson-Golabi-Behmel syndrome (SGBS) is an X-linked overgrowth syndrome with associated visceral and skeletal anomalies. Deletions or point mutations involving the glypican-3 (GPC3) gene at Xq26 are associated with a relatively milder form of this disorder (SGBS1). GPC3 encodes a putative extracellular proteoglycan, glypican-3, that is inferred to play an important role in growth control in embryonic mesodermal tissues in which it is selectively expressed. It appears to form a complex with insulin-like growth factor-II (IGF-II), and might thereby modulate IGF-II action. We reviewed the clinical findings of all published patients with SGBS1 with GPC3 mutations to confirm the clinical specificity for the SGBS1 phenotype. Moreover, we report on a new patient with a GPC3 deletion and IGF-II evaluation.

  4. FANCM c.5791C>T nonsense mutation (rs144567652) induces exon skipping, affects DNA repair activity and is a familial breast cancer risk factor.

    PubMed

    Peterlongo, Paolo; Catucci, Irene; Colombo, Mara; Caleca, Laura; Mucaki, Eliseos; Bogliolo, Massimo; Marin, Maria; Damiola, Francesca; Bernard, Loris; Pensotti, Valeria; Volorio, Sara; Dall'Olio, Valentina; Meindl, Alfons; Bartram, Claus; Sutter, Christian; Surowy, Harald; Sornin, Valérie; Dondon, Marie-Gabrielle; Eon-Marchais, Séverine; Stoppa-Lyonnet, Dominique; Andrieu, Nadine; Sinilnikova, Olga M; Mitchell, Gillian; James, Paul A; Thompson, Ella; Marchetti, Marina; Verzeroli, Cristina; Tartari, Carmen; Capone, Gabriele Lorenzo; Putignano, Anna Laura; Genuardi, Maurizio; Medici, Veronica; Marchi, Isabella; Federico, Massimo; Tognazzo, Silvia; Matricardi, Laura; Agata, Simona; Dolcetti, Riccardo; Della Puppa, Lara; Cini, Giulia; Gismondi, Viviana; Viassolo, Valeria; Perfumo, Chiara; Mencarelli, Maria Antonietta; Baldassarri, Margherita; Peissel, Bernard; Roversi, Gaia; Silvestri, Valentina; Rizzolo, Piera; Spina, Francesca; Vivanet, Caterina; Tibiletti, Maria Grazia; Caligo, Maria Adelaide; Gambino, Gaetana; Tommasi, Stefania; Pilato, Brunella; Tondini, Carlo; Corna, Chiara; Bonanni, Bernardo; Barile, Monica; Osorio, Ana; Benitez, Javier; Balestrino, Luisa; Ottini, Laura; Manoukian, Siranoush; Pierotti, Marco A; Renieri, Alessandra; Varesco, Liliana; Couch, Fergus J; Wang, Xianshu; Devilee, Peter; Hilbers, Florentine S; van Asperen, Christi J; Viel, Alessandra; Montagna, Marco; Cortesi, Laura; Diez, Orland; Balmaña, Judith; Hauke, Jan; Schmutzler, Rita K; Papi, Laura; Pujana, Miguel Angel; Lázaro, Conxi; Falanga, Anna; Offit, Kenneth; Vijai, Joseph; Campbell, Ian; Burwinkel, Barbara; Kvist, Anders; Ehrencrona, Hans; Mazoyer, Sylvie; Pizzamiglio, Sara; Verderio, Paolo; Surralles, Jordi; Rogan, Peter K; Radice, Paolo

    2015-09-15

    Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28-12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04-12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09-13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer.

  5. FANCM c.5791C>T nonsense mutation (rs144567652) induces exon skipping, affects DNA repair activity and is a familial breast cancer risk factor

    PubMed Central

    Peterlongo, Paolo; Catucci, Irene; Colombo, Mara; Caleca, Laura; Mucaki, Eliseos; Bogliolo, Massimo; Marin, Maria; Damiola, Francesca; Bernard, Loris; Pensotti, Valeria; Volorio, Sara; Dall'Olio, Valentina; Meindl, Alfons; Bartram, Claus; Sutter, Christian; Surowy, Harald; Sornin, Valérie; Dondon, Marie-Gabrielle; Eon-Marchais, Séverine; Stoppa-Lyonnet, Dominique; Andrieu, Nadine; Sinilnikova, Olga M.; Mitchell, Gillian; James, Paul A.; Thompson, Ella; Marchetti, Marina; Verzeroli, Cristina; Tartari, Carmen; Capone, Gabriele Lorenzo; Putignano, Anna Laura; Genuardi, Maurizio; Medici, Veronica; Marchi, Isabella; Federico, Massimo; Tognazzo, Silvia; Matricardi, Laura; Agata, Simona; Dolcetti, Riccardo; Puppa, Lara Della; Cini, Giulia; Gismondi, Viviana; Viassolo, Valeria; Perfumo, Chiara; Mencarelli, Maria Antonietta; Baldassarri, Margherita; Peissel, Bernard; Roversi, Gaia; Silvestri, Valentina; Rizzolo, Piera; Spina, Francesca; Vivanet, Caterina; Tibiletti, Maria Grazia; Caligo, Maria Adelaide; Gambino, Gaetana; Tommasi, Stefania; Pilato, Brunella; Tondini, Carlo; Corna, Chiara; Bonanni, Bernardo; Barile, Monica; Osorio, Ana; Benitez, Javier; Balestrino, Luisa; Ottini, Laura; Manoukian, Siranoush; Pierotti, Marco A.; Renieri, Alessandra; Varesco, Liliana; Couch, Fergus J.; Wang, Xianshu; Devilee, Peter; Hilbers, Florentine S.; van Asperen, Christi J.; Viel, Alessandra; Montagna, Marco; Cortesi, Laura; Diez, Orland; Balmaña, Judith; Hauke, Jan; Schmutzler, Rita K.; Papi, Laura; Pujana, Miguel Angel; Lázaro, Conxi; Falanga, Anna; Offit, Kenneth; Vijai, Joseph; Campbell, Ian; Burwinkel, Barbara; Kvist, Anders; Ehrencrona, Hans; Mazoyer, Sylvie; Pizzamiglio, Sara; Verderio, Paolo; Surralles, Jordi; Rogan, Peter K.; Radice, Paolo

    2015-01-01

    Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28–12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04–12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09–13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer. PMID:26130695

  6. FANCM c.5791C>T nonsense mutation (rs144567652) induces exon skipping, affects DNA repair activity and is a familial breast cancer risk factor.

    PubMed

    Peterlongo, Paolo; Catucci, Irene; Colombo, Mara; Caleca, Laura; Mucaki, Eliseos; Bogliolo, Massimo; Marin, Maria; Damiola, Francesca; Bernard, Loris; Pensotti, Valeria; Volorio, Sara; Dall'Olio, Valentina; Meindl, Alfons; Bartram, Claus; Sutter, Christian; Surowy, Harald; Sornin, Valérie; Dondon, Marie-Gabrielle; Eon-Marchais, Séverine; Stoppa-Lyonnet, Dominique; Andrieu, Nadine; Sinilnikova, Olga M; Mitchell, Gillian; James, Paul A; Thompson, Ella; Marchetti, Marina; Verzeroli, Cristina; Tartari, Carmen; Capone, Gabriele Lorenzo; Putignano, Anna Laura; Genuardi, Maurizio; Medici, Veronica; Marchi, Isabella; Federico, Massimo; Tognazzo, Silvia; Matricardi, Laura; Agata, Simona; Dolcetti, Riccardo; Della Puppa, Lara; Cini, Giulia; Gismondi, Viviana; Viassolo, Valeria; Perfumo, Chiara; Mencarelli, Maria Antonietta; Baldassarri, Margherita; Peissel, Bernard; Roversi, Gaia; Silvestri, Valentina; Rizzolo, Piera; Spina, Francesca; Vivanet, Caterina; Tibiletti, Maria Grazia; Caligo, Maria Adelaide; Gambino, Gaetana; Tommasi, Stefania; Pilato, Brunella; Tondini, Carlo; Corna, Chiara; Bonanni, Bernardo; Barile, Monica; Osorio, Ana; Benitez, Javier; Balestrino, Luisa; Ottini, Laura; Manoukian, Siranoush; Pierotti, Marco A; Renieri, Alessandra; Varesco, Liliana; Couch, Fergus J; Wang, Xianshu; Devilee, Peter; Hilbers, Florentine S; van Asperen, Christi J; Viel, Alessandra; Montagna, Marco; Cortesi, Laura; Diez, Orland; Balmaña, Judith; Hauke, Jan; Schmutzler, Rita K; Papi, Laura; Pujana, Miguel Angel; Lázaro, Conxi; Falanga, Anna; Offit, Kenneth; Vijai, Joseph; Campbell, Ian; Burwinkel, Barbara; Kvist, Anders; Ehrencrona, Hans; Mazoyer, Sylvie; Pizzamiglio, Sara; Verderio, Paolo; Surralles, Jordi; Rogan, Peter K; Radice, Paolo

    2015-09-15

    Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28-12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04-12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09-13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer. PMID:26130695

  7. Mutations in the Atp1p and Atp3p subunits of yeast ATP synthase differentially affect respiration and fermentation in Saccharomyces cerevisiae.

    PubMed

    Francis, Brian R; White, Karen H; Thorsness, Peter E

    2007-04-01

    ATP1-111, a suppressor of the slow-growth phenotype of yme1Delta lacking mitochondrial DNA is due to the substitution of phenylalanine for valine at position 111 of the alpha-subunit of mitochondrial ATP synthase (Atp1p in yeast). The suppressing activity of ATP1-111 requires intact beta (Atp2p) and gamma (Atp3p) subunits of mitochondrial ATP synthase, but not the stator stalk subunits b (Atp4p) and OSCP (Atp5p). ATP1-111 and other similarly suppressing mutations in ATP1 and ATP3 increase the growth rate of wild-type strains lacking mitochondrial DNA. These suppressing mutations decrease the growth rate of yeast containing an intact mitochondrial chromosome on media requiring oxidative phosphorylation, but not when grown on fermentable media. Measurement of chronological aging of yeast in culture reveals that ATP1 and ATP3 suppressor alleles in strains that contain mitochondrial DNA are longer lived than the isogenic wild-type strain. In contrast, the chronological life span of yeast cells lacking mitochondrial DNA and containing these mutations is shorter than that of the isogenic wild-type strain. Spore viability of strains bearing ATP1-111 is reduced compared to wild type, although ATP1-111 enhances the survival of spores that lacked mitochondrial DNA.

  8. The c.-360 T>C mutation affects PGAM2 transcription activity and is linked with the water holding capacity of the longissimus lumborum muscle in pigs.

    PubMed

    Yang, Haoxin; He, Jiawen; Wei, Wei; Chu, Weiwei; Yu, Shigang; Tian, Ye; Peng, Fengyi; Liu, Hongcheng; Zhang, Zengkai; Chen, Jie

    2016-12-01

    The phosphoglycerate mutase 2 (PGAM2) gene encodes a key enzyme in the glycolytic process. This study examined a functional mutation in the PGAM2 gene and evaluated its relationship with water holding capacity (WHC). RT-qPCR analysis showed the PGAM2 mRNA level was significantly higher in the low-WHC group than in the high-WHC group (P<0.05). The c.-360 T>C mutation was identified through sequencing and found to have opposite allele distributions in the two groups. The allele was further genotyped in 170 Duroc×Large White×Yorkshire crossbred pigs using allele-specific PCR. The CC genotype was associated with lower WHC and higher PGAM2 mRNA levels, whereas the TT genotype corresponded to a higher WHC and lower PGAM2 mRNA levels (P<0.05). A luciferase activity assay also showed that the CC-genotype promoter had higher activity than the TT-genotype promoter (P<0.05). In conclusion, we discovered the c.-360 T>C mutation in the PGAM2 gene, which is a promising marker for improving pork WHC. PMID:27538264

  9. Mutation of the phospholipase C-γ1–binding site of LAT affects both positive and negative thymocyte selection

    PubMed Central

    Sommers, Connie L.; Lee, Jan; Steiner, Kevin L.; Gurson, Jordan M.; DePersis, Corinne L.; El-Khoury, Dalal; Fuller, Claudette L.; Shores, Elizabeth W.; Love, Paul E.; Samelson, Lawrence E.

    2005-01-01

    Linker for activation of T cells (LAT) is a scaffolding adaptor protein that is critical for T cell development and function. A mutation of LAT (Y136F) that disrupts phospholipase C-γ1 activation and subsequent calcium influx causes a partial block in T cell development and leads to a severe lymphoproliferative disease in homozygous knock-in mice. One possible contribution to the fatal disease of LAT Y136F knock-in mice could be from autoreactive T cells generated in these mice because of altered thymocyte selection. To examine the impact of the LAT Y136F mutation on thymocyte positive and negative selection, we bred this mutation onto the HY T cell receptor (TCR) transgenic, recombination activating gene-2 knockout background. Female mice with this genotype showed a severe defect in positive selection, whereas male mice exhibited a phenotype resembling positive selection (i.e., development and survival of CD8hi HY TCR-specific T cells) instead of negative selection. These results support the hypothesis that in non-TCR transgenic, LAT Y136F knock-in mice, altered thymocyte selection leads to the survival and proliferation of autoreactive T cells that would otherwise be negatively selected in the thymus. PMID:15795236

  10. Mutations in Protein-Binding Hot-Spots on the Hub Protein Smad3 Differentially Affect Its Protein Interactions and Smad3-Regulated Gene Expression

    PubMed Central

    Schiro, Michelle M.; Stauber, Sara E.; Peterson, Tami L.; Krueger, Chateen; Darnell, Steven J.; Satyshur, Kenneth A.; Drinkwater, Norman R.; Newton, Michael A.; Hoffmann, F. Michael

    2011-01-01

    Background Hub proteins are connected through binding interactions to many other proteins. Smad3, a mediator of signal transduction induced by transforming growth factor beta (TGF-β), serves as a hub protein for over 50 protein-protein interactions. Different cellular responses mediated by Smad3 are the product of cell-type and context dependent Smad3-nucleated protein complexes acting in concert. Our hypothesis is that perturbation of this spectrum of protein complexes by mutation of single protein-binding hot-spots on Smad3 will have distinct consequences on Smad3-mediated responses. Methodology/Principal Findings We mutated 28 amino acids on the surface of the Smad3 MH2 domain and identified 22 Smad3 variants with reduced binding to subsets of 17 Smad3-binding proteins including Smad4, SARA, Ski, Smurf2 and SIP1. Mutations defective in binding to Smad4, e.g., D408H, or defective in nucleocytoplasmic shuttling, e.g., W406A, were compromised in modulating the expression levels of a Smad3-dependent reporter gene or six endogenous Smad3-responsive genes: Mmp9, IL11, Tnfaip6, Fermt1, Olfm2 and Wnt11. However, the Smad3 mutants Y226A, Y297A, W326A, K341A, and E267A had distinct differences on TGF-β signaling. For example, K341A and Y226A both reduced the Smad3-mediated activation of the reporter gene by ∼50% but K341A only reduced the TGF-β inducibilty of Olfm2 in contrast to Y226A which reduced the TGF-β inducibility of all six endogenous genes as severely as the W406A mutation. E267A had increased protein binding but reduced TGF-β inducibility because it caused higher basal levels of expression. Y297A had increased TGF-β inducibility because it caused lower Smad3-induced basal levels of gene expression. Conclusions/Significance Mutations in protein binding hot-spots on Smad3 reduced the binding to different subsets of interacting proteins and caused a range of quantitative changes in the expression of genes induced by Smad3. This approach should be useful

  11. The high-affinity poplar ammonium importer PttAMT1.2 and its role in ectomycorrhizal symbiosis.

    PubMed

    Selle, Anita; Willmann, Martin; Grunze, Nina; Gessler, Arthur; Weiss, Michael; Nehls, Uwe

    2005-12-01

    One way to elucidate whether ammonium could act as a nitrogen (N) source delivered by the fungus in ectomycorrhizal symbiosis is to investigate plant ammonium importers. Expression analysis of a high-affinity ammonium importer from Populus tremulax tremuloides (PttAMT1.2) and of known members of the AMT1 gene family from Populus trichocarpa was performed. In addition, PttAMT1.2 function was studied in detail by heterologous expression in yeast. PttAMT1.2 expression proved to be root-specific, affected by N nutrition, and strongly increased in a N-independent manner upon ectomycorrhiza formation. The corresponding protein had a K(M) value for ammonium of c. 52 microm. From the seven members of the AMT1 gene family, one gene was exclusively expressed in roots while four genes were detectable in all poplar organs but with varying degrees of expression. Ectomycorrhiza formation resulted in a strong upregulation of three of these genes. Our results indicate an increased ammonium uptake capacity of mycorrhized poplar roots and suggest, together with the expression of putative ammonium exporter genes in the ectomycorrhizal fungus Amanita muscaria, that ammonium could be a major N source delivered from the fungus towards the plant in symbiosis.

  12. Mutations in zebrafish leucine-rich repeat-containing six-like affect cilia motility and result in pronephric cysts, but have variable effects on left-right patterning.

    PubMed

    Serluca, Fabrizio C; Xu, Bo; Okabe, Noriko; Baker, Kari; Lin, Shin-Yi; Sullivan-Brown, Jessica; Konieczkowski, David J; Jaffe, Kimberly M; Bradner, Joshua M; Fishman, Mark C; Burdine, Rebecca D

    2009-05-01

    Cilia defects have been implicated in a variety of human diseases and genetic disorders, but how cilia motility contributes to these phenotypes is still unknown. To further our understanding of how cilia function in development, we have cloned and characterized two alleles of seahorse, a zebrafish mutation that results in pronephric cysts. seahorse encodes Lrrc6l, a leucine-rich repeat-containing protein that is highly conserved in organisms that have motile cilia. seahorse is expressed in zebrafish tissues known to contain motile cilia. Although mutants do not affect cilia structure and retain the ability to interact with Disheveled, both alleles of seahorse strongly affect cilia motility in the zebrafish pronephros and neural tube. Intriguingly, although seahorse mutations variably affect fluid flow in Kupffer's vesicle, they can have very weak effects on left-right patterning. Combined with recently published results, our alleles suggest that the function of seahorse in cilia motility is separable from its function in other cilia-related phenotypes.

  13. Bacterial Molecular Signals in the Sinorhizobium fredii-Soybean Symbiosis.

    PubMed

    López-Baena, Francisco J; Ruiz-Sainz, José E; Rodríguez-Carvajal, Miguel A; Vinardell, José M

    2016-01-01

    Sinorhizobium (Ensifer) fredii (S. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. Thus, S. fredii is able to effectively nodulate dozens of different legumes, including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as Glycyrrhiza uralensis and pigeon-pea. This capacity of adaptation to different symbioses makes the study of the molecular signals produced by S. fredii strains of increasing interest since it allows the analysis of their symbiotic role in different types of nodule. In this review, we analyze in depth different S. fredii molecules that act as signals in symbiosis, including nodulation factors, different surface polysaccharides (exopolysaccharides, lipopolysaccharides, cyclic glucans, and K-antigen capsular polysaccharides), and effectors delivered to the interior of the host cells through a symbiotic type 3 secretion system. PMID:27213334

  14. Nuclear energy and waste management pyroprocess for system symbiosis

    NASA Astrophysics Data System (ADS)

    Ogawa, Toru; Minato, Kazuo; Okamoto, Yoshihiro; Nishihara, Kenji

    2007-01-01

    The actinide management has become a key issue in nuclear energy. Recovering and fissioning transuranium elements reduce the long-term proliferation risks and the environmental burden. The better way of waste management will be made by system symbiosis: a combination of light-water reactor and fast reactor and/or accelerator-driven transmutation system should be sought. The new recycling technology should be able to achieve good economy with smaller plants, which can process fuels from different types of reactors on a common technical basis. Ease in handling the higher heat load of transuranium nuclides is also important. Pyroprocesses with the use of molten salts are regarded as the strong candidate for such recycling technology. In JAEA, the first laboratory for the high-temperature chemistry of Am and Cm has been established. The fundamental data will be combined with the computer code for predicting the molten-salts electrolytic processes.

  15. Long-distance transport of signals during symbiosis

    PubMed Central

    Xie, Zhi-Ping; Illana, Antonio

    2011-01-01

    Legumes enter nodule symbioses with nitrogen-fixing bacteria (rhizobia), whereas most flowering plants establish symbiotic associations with arbuscular mycorrhizal (AM) fungi. Once first steps of symbiosis are initiated, nodule formation and mycorrhization in legumes is negatively controlled by a shoot-derived inhibitor (SDI), a phenomenon termed autoregulation. According to current views, autoregulation of nodulation and mycorrhization in legumes is regulated in a similar way. CLE peptides induced in response to rhizobial nodulation signals (Nod factors) have been proposed to represent the ascending long-distance signals to the shoot. Although not proven yet, these CLE peptides are likely perceived by leucine-rich repeat (LRR) autoregulation receptor kinases in the shoot. Autoregulation of mycorrhization in non-legumes is reminiscent to the phenomenon of “systemic acquired resistance” in plant-pathogen interactions. PMID:21455020

  16. Bacterial Molecular Signals in the Sinorhizobium fredii-Soybean Symbiosis

    PubMed Central

    López-Baena, Francisco J.; Ruiz-Sainz, José E.; Rodríguez-Carvajal, Miguel A.; Vinardell, José M.

    2016-01-01

    Sinorhizobium (Ensifer) fredii (S. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. Thus, S. fredii is able to effectively nodulate dozens of different legumes, including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as Glycyrrhiza uralensis and pigeon-pea. This capacity of adaptation to different symbioses makes the study of the molecular signals produced by S. fredii strains of increasing interest since it allows the analysis of their symbiotic role in different types of nodule. In this review, we analyze in depth different S. fredii molecules that act as signals in symbiosis, including nodulation factors, different surface polysaccharides (exopolysaccharides, lipopolysaccharides, cyclic glucans, and K-antigen capsular polysaccharides), and effectors delivered to the interior of the host cells through a symbiotic type 3 secretion system. PMID:27213334

  17. Making the Most of Omics for Symbiosis Research

    PubMed Central

    Chaston, J.; Douglas, A.E.

    2012-01-01

    Omics, including genomics, proteomics and metabolomics, enable us to explain symbioses in terms of the underlying molecules and their interactions. The central task is to transform molecular catalogs of genes, metabolites etc. into a dynamic understanding of symbiosis function. We review four exemplars of omics studies that achieve this goal, through defined biological questions relating to metabolic integration and regulation of animal-microbial symbioses, the genetic autonomy of bacterial symbionts, and symbiotic protection of animal hosts from pathogens. As omic datasets become increasingly complex, computationally-sophisticated downstream analyses are essential to reveal interactions not evident to visual inspection of the data. We discuss two approaches, phylogenomics and transcriptional clustering, that can divide the primary output of omics studies – long lists of factors – into manageable subsets, and we describe how they have been applied to analyze large datasets and generate testable hypotheses. PMID:22983030

  18. Commensal bacteria direct selective cargo sorting to promote symbiosis.

    PubMed

    Zhang, Qin; Pan, Ying; Yan, Ruiqing; Zeng, Benhua; Wang, Haifang; Zhang, Xinwen; Li, Wenxia; Wei, Hong; Liu, Zhihua

    2015-09-01

    Mucosal immunity protects a host from intestinal inflammation and infection and is profoundly influenced by symbiotic bacteria. Here we report that in mice symbiotic bacteria directed selective cargo sorting in Paneth cells to promote symbiosis through Nod2, a cytosolic bacterial sensor, and the multifunctional protein kinase LRRK2, both encoded by inflammatory bowel disease (IBD)-associated genes. Commensals recruited Nod2 onto lysozyme-containing dense core vesicles (DCVs), which was required for DCV localization of LRRK2 and a small GTPase, Rab2a. Deficiency of Nod2, LRRK2 or Rab2a or depletion of commensals resulted in lysosomal degradation of lysozyme. Thus, commensal bacteria and host factors orchestrate the lysozyme-sorting process to protect the host from enteric infection, implicating Paneth cell dysfunction in IBD pathogenesis.

  19. Mutations and environmental factors affecting regulation of riboflavin synthesis and iron assimilation also cause oxidative stress in the yeast Pichia guilliermondii.

    PubMed

    Boretsky, Yuriy R; Protchenko, Olga V; Prokopiv, Tetiana M; Mukalov, Igor O; Fedorovych, Daria V; Sibirny, Andriy A

    2007-10-01

    Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. However, the mechanisms of such regulation are not known. We found that mutations causing riboflavin overproduction and iron hyperaccumulation (rib80, rib81 and hit1), as well as cobalt excess or iron deficiency all provoke oxidative stress in the Pichia guilliermondii yeast. Iron content in the cells, production both of riboflavin and malondialdehyde by P. guilliermondii wild type and hit1 mutant strains depend on a type of carbon source used in cultivation media. The data suggest that the regulation of riboflavin biosynthesis and iron assimilation in P. guilliermondii are linked with cellular oxidative state. PMID:17910100

  20. Mutations acquired during cell culture isolation may affect antigenic characterisation of influenza A(H3N2) clade 3C.2a viruses.

    PubMed

    Skowronski, Danuta M; Sabaiduc, Suzana; Chambers, Catharine; Eshaghi, Alireza; Gubbay, Jonathan B; Krajden, Mel; Drews, Steven J; Martineau, Christine; De Serres, Gaston; Dickinson, James A; Winter, Anne-Luise; Bastien, Nathalie; Li, Yan

    2016-01-01

    As elsewhere, few (< 15%) sentinel influenza A(H3N2) clade 3C.2a viruses that dominated in Canada during the 2014/15 season could be antigenically characterised by haemagglutination inhibition (HI) assay. Clade 3C.2a viruses that could be HI-characterised had acquired genetic mutations during in vitro cell culture isolation that modified the potential glycosylation motif found in original patient specimens and the consensus sequence of circulating viruses at amino acid positions 158-160 of the haemagglutinin protein. Caution is warranted in extrapolating antigenic relatedness based on limited HI findings for clade 3C.2a viruses that continue to circulate globally.

  1. Identification and characterization of mutations in the UPF1 gene that affect nonsense suppression and the formation of the Upf protein complex but not mRNA turnover.

    PubMed Central

    Weng, Y; Czaplinski, K; Peltz, S W

    1996-01-01

    To understand the relationship between translation and mRNA decay, we have been studying how premature translation termination accelerates the degradation of mRNAs. In the yeast Saccharomyces cerevisiae, the Upf1 protein (Upf1p), which contains a cysteine- and histidine-rich region and nucleoside triphosphate hydrolysis and helicase motifs, was shown to be a trans-acting factor in this decay pathway. A UPF1 gene disruption results in the stabilization of nonsense-containing mRNAs and leads to a nonsense suppression phenotype. Biochemical analysis of the wild-type Upf1p demonstrated that it has RNA-dependent ATPase, RNA helicase, and RNA binding activities. In the work described in the accompanying paper (Y. Weng, K. Czaplinski, and S. W. Peltz, Mol. Cell. Biol. 16:5477-5490, 1996) mutations in the helicase region of Upf1p that inactivated its mRNA decay function but prevented suppression of leu2-2 and tyr7-1 nonsense alleles are identified. On the basis of these results, we suggested that Upf1p is a multifunctional protein involved in modulating mRNA decay and translation termination at nonsense codons. If this is true, we predict that UPF1 mutations with the converse phenotype should be identified. In this report, we describe the identification and biochemical characterization of mutations in the amino-terminal cysteine- and histidine-rich region of Upf1p that have normal nonsense-mediated mRNA decay activities but are able to suppress leu2-2 and tyr7-1 nonsense alleles. Biochemical characterization of these mutant proteins demonstrated that they have altered RNA binding properties. Furthermore, using the two-hybrid system, we characterized the Upf1p-Upf2p interactions and demonstrated that Upf2p interacts with Upf3p. Mutations in the cysteine- and histidine-rich region of Upf1p abolish Upf1p-Upf2p interaction. On the basis of these results, the role of the Upf complex in nonsense-mediated mRNA decay and nonsense suppression is discussed. PMID:8816462

  2. Arbuscular mycorrhizal fungi in terms of symbiosis-parasitism continuum.

    PubMed

    Schmidt, B; Gaşpar, S; Camen, D; Ciobanu, I; Sumălan, R

    2011-01-01

    adverse climatic conditions, like temperature shock at the beginning of growing period modified the nature of symbiosis. In this case, the physiological parameters were reduced at colonized plants, while usual, constant growing conditions permitted the normal, efficient and beneficial development of symbiosis. PMID:22702184

  3. Species specificity of symbiosis and secondary metabolism in ascidians

    PubMed Central

    Tianero, Ma Diarey B; Kwan, Jason C; Wyche, Thomas P; Presson, Angela P; Koch, Michael; Barrows, Louis R; Bugni, Tim S; Schmidt, Eric W

    2015-01-01

    Ascidians contain abundant, diverse secondary metabolites, which are thought to serve a defensive role and which have been applied to drug discovery. It is known that bacteria in symbiosis with ascidians produce several of these metabolites, but very little is known about factors governing these ‘chemical symbioses'. To examine this phenomenon across a wide geographical and species scale, we performed bacterial and chemical analyses of 32 different ascidians, mostly from the didemnid family from Florida, Southern California and a broad expanse of the tropical Pacific Ocean. Bacterial diversity analysis showed that ascidian microbiomes are highly diverse, and this diversity does not correlate with geographical location or latitude. Within a subset of species, ascidian microbiomes are also stable over time (R=−0.037, P-value=0.499). Ascidian microbiomes and metabolomes contain species-specific and location-specific components. Location-specific bacteria are found in low abundance in the ascidians and mostly represent strains that are widespread. Location-specific metabolites consist largely of lipids, which may reflect differences in water temperature. By contrast, species-specific bacteria are mostly abundant sequenced components of the microbiomes and include secondary metabolite producers as major components. Species-specific chemicals are dominated by secondary metabolites. Together with previous analyses that focused on single ascidian species or symbiont type, these results reveal fundamental properties of secondary metabolic symbiosis. Different ascidian species have established associations with many different bacterial symbionts, including those known to produce toxic chemicals. This implies a strong selection for this property and the independent origin of secondary metabolite-based associations in different ascidian species. The analysis here streamlines the connection of secondary metabolite to producing bacterium, enabling further biological and

  4. Lichen Symbiosis: Nature's High Yielding Machines for Induced Hydrogen Production

    PubMed Central

    Papazi, Aikaterini; Kastanaki, Elizabeth; Pirintsos, Stergios; Kotzabasis, Kiriakos

    2015-01-01

    Hydrogen is a promising future energy source. Although the ability of green algae to produce hydrogen has long been recognized (since 1939) and several biotechnological applications have been attempted, the greatest obstacle, being the O2-sensitivity of the hydrogenase enzyme, has not yet been overcome. In the present contribution, 75 years after the first report on algal hydrogen production, taking advantage of a natural mechanism of oxygen balance, we demonstrate high hydrogen yields by lichens. Lichens have been selected as the ideal organisms in nature for hydrogen production, since they consist of a mycobiont and a photobiont in symbiosis. It has been hypothesized that the mycobiont’s and photobiont’s consumption of oxygen (increase of COX and AOX proteins of mitochondrial respiratory pathways and PTOX protein of chrolorespiration) establishes the required anoxic conditions for the activation of the phycobiont’s hydrogenase in a closed system. Our results clearly supported the above hypothesis, showing that lichens have the ability to activate appropriate bioenergetic pathways depending on the specific incubation conditions. Under light conditions, they successfully use the PSII-dependent and the PSII-independent pathways (decrease of D1 protein and parallel increase of PSaA protein) to transfer electrons to hydrogenase, while under dark conditions, lichens use the PFOR enzyme and the dark fermentative pathway to supply electrons to hydrogenase. These advantages of lichen symbiosis in combination with their ability to survive in extreme environments (while in a dry state) constitute them as unique and valuable hydrogen producing natural factories and pave the way for future biotechnological applications. PMID:25826211

  5. Lichen symbiosis: nature's high yielding machines for induced hydrogen production.

    PubMed

    Papazi, Aikaterini; Kastanaki, Elizabeth; Pirintsos, Stergios; Kotzabasis, Kiriakos

    2015-01-01

    Hydrogen is a promising future energy source. Although the ability of green algae to produce hydrogen has long been recognized (since 1939) and several biotechnological applications have been attempted, the greatest obstacle, being the O2-sensitivity of the hydrogenase enzyme, has not yet been overcome. In the present contribution, 75 years after the first report on algal hydrogen production, taking advantage of a natural mechanism of oxygen balance, we demonstrate high hydrogen yields by lichens. Lichens have been selected as the ideal organisms in nature for hydrogen production, since they consist of a mycobiont and a photobiont in symbiosis. It has been hypothesized that the mycobiont's and photobiont's consumption of oxygen (increase of COX and AOX proteins of mitochondrial respiratory pathways and PTOX protein of chrolorespiration) establishes the required anoxic conditions for the activation of the phycobiont's hydrogenase in a closed system. Our results clearly supported the above hypothesis, showing that lichens have the ability to activate appropriate bioenergetic pathways depending on the specific incubation conditions. Under light conditions, they successfully use the PSII-dependent and the PSII-independent pathways (decrease of D1 protein and parallel increase of PSaA protein) to transfer electrons to hydrogenase, while under dark conditions, lichens use the PFOR enzyme and the dark fermentative pathway to supply electrons to hydrogenase. These advantages of lichen symbiosis in combination with their ability to survive in extreme environments (while in a dry state) constitute them as unique and valuable hydrogen producing natural factories and pave the way for future biotechnological applications.

  6. Lichen symbiosis: nature's high yielding machines for induced hydrogen production.

    PubMed

    Papazi, Aikaterini; Kastanaki, Elizabeth; Pirintsos, Stergios; Kotzabasis, Kiriakos

    2015-01-01

    Hydrogen is a promising future energy source. Although the ability of green algae to produce hydrogen has long been recognized (since 1939) and several biotechnological applications have been attempted, the greatest obstacle, being the O2-sensitivity of the hydrogenase enzyme, has not yet been overcome. In the present contribution, 75 years after the first report on algal hydrogen production, taking advantage of a natural mechanism of oxygen balance, we demonstrate high hydrogen yields by lichens. Lichens have been selected as the ideal organisms in nature for hydrogen production, since they consist of a mycobiont and a photobiont in symbiosis. It has been hypothesized that the mycobiont's and photobiont's consumption of oxygen (increase of COX and AOX proteins of mitochondrial respiratory pathways and PTOX protein of chrolorespiration) establishes the required anoxic conditions for the activation of the phycobiont's hydrogenase in a closed system. Our results clearly supported the above hypothesis, showing that lichens have the ability to activate appropriate bioenergetic pathways depending on the specific incubation conditions. Under light conditions, they successfully use the PSII-dependent and the PSII-independent pathways (decrease of D1 protein and parallel increase of PSaA protein) to transfer electrons to hydrogenase, while under dark conditions, lichens use the PFOR enzyme and the dark fermentative pathway to supply electrons to hydrogenase. These advantages of lichen symbiosis in combination with their ability to survive in extreme environments (while in a dry state) constitute them as unique and valuable hydrogen producing natural factories and pave the way for future biotechnological applications. PMID:25826211

  7. Harnessing mosquito-Wolbachia symbiosis for vector and disease control.

    PubMed

    Bourtzis, Kostas; Dobson, Stephen L; Xi, Zhiyong; Rasgon, Jason L; Calvitti, Maurizio; Moreira, Luciano A; Bossin, Hervé C; Moretti, Riccardo; Baton, Luke Anthony; Hughes, Grant L; Mavingui, Patrick; Gilles, Jeremie R L

    2014-04-01

    Mosquito species, members of the genera Aedes, Anopheles and Culex, are the major vectors of human pathogens including protozoa (Plasmodium sp.), filariae and of a variety of viruses (causing dengue, chikungunya, yellow fever, West Nile). There is lack of efficient methods and tools to treat many of the diseases caused by these major human pathogens, since no efficient vaccines or drugs are available; even in malaria where insecticide use and drug therapies have reduced incidence, 219 million cases still occurred in 2010. Therefore efforts are currently focused on the control of vector populations. Insecticides alone are insufficient to control mosquito populations since reduced susceptibility and even resistance is being observed more and more frequently. There is also increased concern about the toxic effects of insecticides on non-target (even beneficial) insect populations, on humans and the environment. During recent years, the role of symbionts in the biology, ecology and evolution of insect species has been well-documented and has led to suggestions that they could potentially be used as tools to control pests and therefore diseases. Wolbachia is perhaps the most renowned insect symbiont, mainly due to its ability to manipulate insect reproduction and to interfere with major human pathogens thus providing new avenues for pest control. We herein present recent achievements in the field of mosquito-Wolbachia symbiosis with an emphasis on Aedes albopictus. We also discuss how Wolbachia symbiosis can be harnessed for vector control as well as the potential to combine the sterile insect technique and Wolbachia-based approaches for the enhancement of population suppression programs. PMID:24252486

  8. Unfolding the secrets of coral–algal symbiosis

    PubMed Central

    Rosic, Nedeljka; Ling, Edmund Yew Siang; Chan, Chon-Kit Kenneth; Lee, Hong Ching; Kaniewska, Paulina; Edwards, David; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-01-01

    Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30 000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral–algal symbiosis. PMID:25343511

  9. Harnessing mosquito-Wolbachia symbiosis for vector and disease control.

    PubMed

    Bourtzis, Kostas; Dobson, Stephen L; Xi, Zhiyong; Rasgon, Jason L; Calvitti, Maurizio; Moreira, Luciano A; Bossin, Hervé C; Moretti, Riccardo; Baton, Luke Anthony; Hughes, Grant L; Mavingui, Patrick; Gilles, Jeremie R L

    2014-04-01

    Mosquito species, members of the genera Aedes, Anopheles and Culex, are the major vectors of human pathogens including protozoa (Plasmodium sp.), filariae and of a variety of viruses (causing dengue, chikungunya, yellow fever, West Nile). There is lack of efficient methods and tools to treat many of the diseases caused by these major human pathogens, since no efficient vaccines or drugs are available; even in malaria where insecticide use and drug therapies have reduced incidence, 219 million cases still occurred in 2010. Therefore efforts are currently focused on the control of vector populations. Insecticides alone are insufficient to control mosquito populations since reduced susceptibility and even resistance is being observed more and more frequently. There is also increased concern about the toxic effects of insecticides on non-target (even beneficial) insect populations, on humans and the environment. During recent years, the role of symbionts in the biology, ecology and evolution of insect species has been well-documented and has led to suggestions that they could potentially be used as tools to control pests and therefore diseases. Wolbachia is perhaps the most renowned insect symbiont, mainly due to its ability to manipulate insect reproduction and to interfere with major human pathogens thus providing new avenues for pest control. We herein present recent achievements in the field of mosquito-Wolbachia symbiosis with an emphasis on Aedes albopictus. We also discuss how Wolbachia symbiosis can be harnessed for vector control as well as the potential to combine the sterile insect technique and Wolbachia-based approaches for the enhancement of population suppression programs.

  10. Species specificity of symbiosis and secondary metabolism in ascidians.

    PubMed

    Tianero, Ma Diarey B; Kwan, Jason C; Wyche, Thomas P; Presson, Angela P; Koch, Michael; Barrows, Louis R; Bugni, Tim S; Schmidt, Eric W

    2015-03-01

    Ascidians contain abundant, diverse secondary metabolites, which are thought to serve a defensive role and which have been applied to drug discovery. It is known that bacteria in symbiosis with ascidians produce several of these metabolites, but very little is known about factors governing these 'chemical symbioses'. To examine this phenomenon across a wide geographical and species scale, we performed bacterial and chemical analyses of 32 different ascidians, mostly from the didemnid family from Florida, Southern California and a broad expanse of the tropical Pacific Ocean. Bacterial diversity analysis showed that ascidian microbiomes are highly diverse, and this diversity does not correlate with geographical location or latitude. Within a subset of species, ascidian microbiomes are also stable over time (R=-0.037, P-value=0.499). Ascidian microbiomes and metabolomes contain species-specific and location-specific components. Location-specific bacteria are found in low abundance in the ascidians and mostly represent strains that are widespread. Location-specific metabolites consist largely of lipids, which may reflect differences in water temperature. By contrast, species-specific bacteria are mostly abundant sequenced components of the microbiomes and include secondary metabolite producers as major components. Species-specific chemicals are dominated by secondary metabolites. Together with previous analyses that focused on single ascidian species or symbiont type, these results reveal fundamental properties of secondary metabolic symbiosis. Different ascidian species have established associations with many different bacterial symbionts, including those known to produce toxic chemicals. This implies a strong selection for this property and the independent origin of secondary metabolite-based associations in different ascidian species. The analysis here streamlines the connection of secondary metabolite to producing bacterium, enabling further biological and

  11. Unfolding the secrets of coral-algal symbiosis.

    PubMed

    Rosic, Nedeljka; Ling, Edmund Yew Siang; Chan, Chon-Kit Kenneth; Lee, Hong Ching; Kaniewska, Paulina; Edwards, David; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-04-01

    Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30,000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral-algal symbiosis.

  12. CbrA is a stationary-phase regulator of cell surface physiology and legume symbiosis in Sinorhizobium meliloti.

    PubMed

    Gibson, Katherine E; Campbell, Gordon R; Lloret, Javier; Walker, Graham C

    2006-06-01

    Sinorhizobium meliloti produces an exopolysaccharide called succinoglycan that plays a critical role in promoting symbiosis with its host legume, alfalfa (Medicago sativa). We performed a transposon mutagenesis and screened for mutants with altered succinoglycan production and a defect in symbiosis. In this way, we identified a putative two-component histidine kinase associated with a PAS sensory domain, now designated CbrA (calcofluor-bright regulator A). The cbrA::Tn5 mutation causes overproduction of succinoglycan and results in increased accumulation of low-molecular-weight forms of this exopolysaccharide. Our results suggest the cbrA::Tn5 allele leads to this succinoglycan phenotype through increased expression of exo genes required for succinoglycan biosynthesis and modification. Interestingly, CbrA-dependent regulation of exo and exs genes is observed almost exclusively during stationary-phase growth. The cbrA::Tn5 mutant also has an apparent cell envelope defect, based on increased sensitivity to a number of toxic compounds, including the bile salt deoxycholate and the hydrophobic dye crystal violet. Growth of the cbrA mutant is also slowed under oxidative-stress conditions. The CbrA-regulated genes exsA and exsE encode putative inner membrane ABC transporters with a high degree of similarity to lipid exporters. ExsA is homologous to the Escherichia coli MsbA protein, which is required for lipopolysaccharide transport, while ExsE is a member of the eukaryotic family of ABCD/hALD peroxisomal membrane proteins involved in transport of very long-chain fatty acids, which are a unique component of the lipopolysaccharides of alphaproteobacteria. Thus, CbrA could play a role in regulating the lipopolysaccharide or lipoprotein components of the cell envelope. PMID:16740957

  13. The R215W mutation in NBS1 impairs {gamma}-H2AX binding and affects DNA repair: molecular bases for the severe phenotype of 657del5/R215W Nijmegen breakage syndrome patients

    SciTech Connect

    Masi, Alessandra di Viganotti, Mara; Polticelli, Fabio; Ascenzi, Paolo; Tanzarella, Caterina; Antoccia, Antonio

    2008-05-09

    Nijmegen breakage syndrome (NBS) is a genetic disorder characterized by chromosomal instability and hypersensitivity to ionising radiation. Compound heterozygous 657del5/R215W NBS patients display a clinical phenotype more severe than the majority of NBS patients homozygous for the 657del5 mutation. The NBS1 protein, mutated in NBS patients, contains a FHA/BRCT domain necessary for the DNA-double strand break (DSB) damage response. Recently, a second BRCT domain has been identified, however, its role is still unknown. Here, we demonstrate that the R215W mutation in NBS1 impairs histone {gamma}-H2AX binding after induction of DNA damage, leading to a delay in DNA-DSB rejoining. Molecular modelling reveals that the 215 residue of NBS1 is located between the two BRCT domains, affecting their relative orientation that appears critical for {gamma}-H2AX binding. Present data represent the first evidence for the role of NBS1 tandem BRCT domains in {gamma}-H2AX recognition, and could explain the severe phenotype observed in 657del5/R215W NBS patients.

  14. Mutations in PurBox1 of the Bacillus subtilis pur operon control site affect adenine-regulated expression in vivo.

    PubMed

    Xuan, Jinsong; Zalkin, Howard; Weng, Manli

    2005-04-01

    Transcription of the Bacillus subtilis pur operon is regulated by a purine repressor (PurR)-DNA control site interaction. The pur operon control site has two PurBoxes that are required for high-affinity PurR binding. An upstream, strong-binding PurBox1 is at position -81 to -68 relative to the transcription start site and a downstream weak-binding PurBox2 is at position -49 to -36. We constructed three PurBox1 mutations and the effects on binding of PurR to the control region in vitro and on regulation of pur operon expression in vivo were investigated. The mutations significantly reduced the binding of PurR to control region DNA. In strains with G-75A, G-75T and a five bp deletion (delta5) pur operon repression was defective in vivo. In addition in vivo PurR titration was used to confirm that sequences flanking PurBox1 and PurBox2 are required for PurR binding to the puroperon control site.

  15. A Missense Mutation in the Zinc Finger Domain of OsCESA7 Deleteriously Affects Cellulose Biosynthesis and Plant Growth in Rice.

    PubMed

    Wang, Daofeng; Qin, Yanling; Fang, Jingjing; Yuan, Shoujiang; Peng, Lixiang; Zhao, Jinfeng; Li, Xueyong

    2016-01-01

    Rice is a model plant species for the study of cellulose biosynthesis. We isolated a mutant, S1-24, from ethyl methanesulfonate (EMS)-treated plants of the japonica rice cultivar, Nipponbare. The mutant exhibited brittle culms and other pleiotropic phenotypes such as dwarfism and partial sterility. The brittle culms resulted from reduced mechanical strength due to a defect in thickening of the sclerenchyma cell wall and reduced cellulose content in the culms of the S1-24 mutant. Map-based gene cloning and a complementation assay showed that phenotypes of the S1-24 mutant were caused by a recessive point mutation in the OsCESA7 gene, which encodes cellulose synthase A subunit 7. The missense mutation changed the highly conserved C40 to Y in the zinc finger domain. The OsCESA7 gene is expressed predominantly in the culm at the mature stage, particularly in mechanical tissues such as vascular bundles and sclerenchyma cells, consistent with the brittle phenotype in the culm. These results indicate that OsCESA7 plays an important role in cellulose biosynthesis and plant growth. PMID:27092937

  16. Structural changes in the hydrophobic hinge region adversely affect the activity and fidelity of the I260Q mutator DNA polymerase β.

    PubMed

    Gridley, Chelsea L; Rangarajan, Sneha; Firbank, Susan; Dalal, Shibani; Sweasy, Joann B; Jaeger, Joachim

    2013-06-25

    The I260Q variant of DNA polymerase β is an efficient mutator polymerase with fairly indiscriminate misincorporation activities opposite all template bases. Previous modeling studies have suggested that I260Q harbors structural variations in its hinge region. Here, we present the crystal structures of wild type and I260Q rat polymerase β in the presence and absence of substrates. Both the I260Q apoenzyme structure and the closed ternary complex with double-stranded DNA and ddTTP show ordered water molecules in the hydrophobic hinge near Gln260, whereas this is not the case in the wild type polymerase. Compared to wild type polymerase β ternary complexes, there are subtle movements around residues 260, 272, 295, and 296 in the mutant. The rearrangements in this region, coupled with side chain movements in the immediate neighborhood of the dNTP-binding pocket, namely, residues 258 and 272, provide an explanation for the altered activity and fidelity profiles observed in the I260Q mutator polymerase.

  17. Mutation of the Plastidial α-Glucan Phosphorylase Gene in Rice Affects the Synthesis and Structure of Starch in the Endosperm[W

    PubMed Central

    Satoh, Hikaru; Shibahara, Kensuke; Tokunaga, Takashi; Nishi, Aiko; Tasaki, Mikako; Hwang, Seon-Kap; Okita, Thomas W.; Kaneko, Nanae; Fujita, Naoko; Yoshida, Mayumi; Hosaka, Yuko; Sato, Aya; Utsumi, Yoshinori; Ohdan, Takashi; Nakamura, Yasunori

    2008-01-01

    Plastidial phosphorylase (Pho1) accounts for ∼96% of the total phosphorylase activity in developing rice (Oryza sativa) seeds. From mutant stocks induced by N-methyl-N-nitrosourea treatment, we identified plants with mutations in the Pho1 gene that are deficient in Pho1. Strikingly, the size of mature seeds and the starch content in these mutants showed considerable variation, ranging from shrunken to pseudonormal. The loss of Pho1 caused smaller starch granules to accumulate and modified the amylopectin structure. Variation in the morphological and biochemical phenotype of individual seeds was common to all 15 pho1-independent homozygous mutant lines studied, indicating that this phenotype was caused solely by the genetic defect. The phenotype of the pho1 mutation was temperature dependent. While the mutant plants grown at 30°C produced mainly plump seeds at maturity, most of the seeds from plants grown at 20°C were shrunken, with a significant proportion showing severe reduction in starch accumulation. These results strongly suggest that Pho1 plays a crucial role in starch biosynthesis in rice endosperm at low temperatures and that one or more other factors can complement the function of Pho1 at high temperatures. PMID:18621947

  18. Germline mutations induced by N-nitroso-N-ethylurea do not affect the inserted copia retrotransposon in a Drosophila melanogaster wa mutant.

    PubMed

    Baldrich, E; Velázquez, A; Xamena, N; Cabré, O

    2003-11-01

    The white-apricot (wa) mutant of Drosophila melanogaster is characterized by a copia retrotransposon inserted in the second intron of the white locus. After germinal exposure to the alkylating agent N-ethyl-N-nitrosourea, we have obtained new phenotypes in the offspring, mainly lighter eye colour, but not revertants to the original phenotype. Subsequent genetic crosses showed that only 3 out of 13 new mutant phenotypes were allelic. Three white gene regions were analysed by Southern blot in order to determine the nature of the mutations. These three regions were the 5' regulatory region, the copia insertion site and the 3' coding region. The results obtained indicate that the treatment does not induce the total or partial excision of copia in the white locus. Two of the new allelic mutants present a 5' or 3' deletion in the white locus. The other new phenotypes seem to be caused by mutations being induced in other loci acting as modifiers, most of them located on the X chromosome. PMID:14614188

  19. The Laccaria and Tuber Genomes Reveal Unique Signatures of Mycorrhizal Symbiosis Evolution (2010 JGI User Meeting)

    SciTech Connect

    Knapp, Steve

    2010-03-24

    Francis Martin from the French agricultural research institute INRA talks on how "The Laccaria and Tuber genomes reveal unique signatures of mycorrhizal symbiosis evolution" on March 24, 2010 at the 5th Annual DOE JGI User Meeting

  20. Landau and Lifshitz' formulation of Le Chatelier's principle: an insight into symbiosis?

    PubMed

    Halabi, T

    2013-12-01

    A correspondence allows application of Landau and Lifshitz' formulation of Le Chatelier's principle from statistical physics to a simple 2-D model of biological symbiosis. The insight: symbionts stabilize the occupation of narrow peaks on fitness landscape. PMID:23851635

  1. Are heterotrophic and silica-rich eukaryotic microbes an important part of the lichen symbiosis?

    PubMed Central

    Wilkinson, David M.; Creevy, Angela L.; Kalu, Chiamaka L.; Schwartzman, David W.

    2015-01-01

    We speculate that heterotrophic and/or silica-rich eukaryotic microorganisms maybe an important part of the lichen symbiosis. None of the very few studies of heterotrophic protists associated with lichens have considered the possibility that they may be of functional significance in the lichen symbiosis. Here we start to develop, currently speculative, theoretical ideas about their potential significance. For example, all the protist taxa identified in lichens we sampled in Ohio USA depend on sili