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1.
Encephale ; 47(4): 326-333, 2021 Aug.
Article in French | MEDLINE | ID: mdl-33198958

ABSTRACT

BACKGROUND: A woman's negative perception of her subjective childbirth experience can have consequences on the mother's psychological state and on early mother-baby relationships. To date, there is no validated tool in France allowing to evaluate childbirth experience in a multidimensional way. The aim of this study is to validate the Questionnaire Assessing the Childbirth Experience (QEVA) in a French sample of mothers. This tool was developed in a previous study where the authors combined 25 items into 6 dimensions: representations and expectations, sensory perceptions, feeling of control, perceived social support (medical staff and partner), emotions (positive and negative) and first moments with the baby. METHODS: The sample included 256 women recruited in a maternity ward. Sociodemographic and obstetric characteristics of our sample were compared to those of the French national perinatal survey. The structure of the QEVA with 17 items was explored by an exploratory structural equation modeling (ESEM). An analysis of the internal consistency was conducted on the sub-scores of the identified factors, and the concurrent validity was assessed with the Peri-traumatic Distress Inventory (PDI) through a correlation and its associated t-test. RESULTS: The characteristics of our sample and those of the national perinatal survey do not differ on age, marital status, parity, cannabis use, infertility treatment, epidural and baby weight, in favour of the good representativeness of our sample. The study of the QEVA structure revealed a 4-dimensional structure. Analysis of the psychometric qualities showed a good internal consistency, with an observed alpha value ranging from 0.69 to 0.86. The QEVA also shows a good concurrent validity with the peri-traumatic distress scores (r=0.51). CONCLUSION: To date, the QEVA is the first standardized tool allowing a multidimensional evaluation of the subjective experience of childbirth. It has been validated on a French population using an exploratory structural equation modeling. This tool, which is simple to use and well accepted by mothers, enables health professionals not only to screen mothers experiencing difficult childbirth and in need of support, but also to adapt health care according to the dimensions of the birth experience and its associated difficulties (emotions during the birth, interactions with health professionals, first moments with the baby, or post-partum emotions).


Subject(s)
Delivery, Obstetric , Parturition , Female , Humans , Pregnancy , Psychometrics , Reproducibility of Results , Surveys and Questionnaires
3.
Mol Psychiatry ; 19(11): 1179-85, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24393808

ABSTRACT

RNA-sequencing (RNA-seq) is a powerful technique to investigate the complexity of gene expression in the human brain. We used RNA-seq to survey the brain transcriptome in high-quality postmortem dorsolateral prefrontal cortex from 11 individuals diagnosed with bipolar disorder (BD) and from 11 age- and gender-matched controls. Deep sequencing was performed, with over 350 million reads per specimen. At a false discovery rate of <5%, we detected five differentially expressed (DE) genes and 12 DE transcripts, most of which have not been previously implicated in BD. Among these, Prominin 1/CD133 and ATP-binding cassette-sub-family G-member2 (ABCG2) have important roles in neuroplasticity. We also show for the first time differential expression of long noncoding RNAs (lncRNAs) in BD. DE transcripts include those of serine/arginine-rich splicing factor 5 (SRSF5) and regulatory factor X4 (RFX4), which along with lncRNAs have a role in mammalian circadian rhythms. The DE genes were significantly enriched for several Gene Ontology categories. Of these, genes involved with GTPase binding were also enriched for BD-associated SNPs from previous genome-wide association studies, suggesting that differential expression of these genes is not simply a consequence of BD or its treatment. Many of these findings were replicated by microarray in an independent sample of 60 cases and controls. These results highlight common pathways for inherited and non-inherited influences on disease risk that may constitute good targets for novel therapies.


Subject(s)
Bipolar Disorder/metabolism , Circadian Rhythm/physiology , GTP Phosphohydrolases/metabolism , Neuronal Plasticity/physiology , Prefrontal Cortex/metabolism , Transcriptome , Adult , Aged , Bipolar Disorder/genetics , Circadian Rhythm/genetics , Female , GTP Phosphohydrolases/genetics , Genome-Wide Association Study , Humans , Male , Meta-Analysis as Topic , Microarray Analysis , Middle Aged , Neuronal Plasticity/genetics , Polymerase Chain Reaction , Principal Component Analysis , Sequence Analysis, RNA/methods , Young Adult
4.
Pharmacogenomics J ; 14(4): 395-9, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24445990

ABSTRACT

It would be beneficial to find genetic predictors of antidepressant response to help personalise treatment of major depressive disorder (MDD). Rare copy number variants (CNVs) have been implicated in several psychiatric disorders, including MDD, but their role in antidepressant response has yet to be investigated. CNV data were available for 1565 individuals with MDD from the NEWMEDS (Novel Methods leading to New Medications in Depression and Schizophrenia) consortium with prospective data on treatment outcome with either a serotonergic or noradrenergic antidepressant. No association was seen between the presence of CNV (rare or common), the overall number of CNVs or genomic CNV 'burden' and antidepressant response. Specific CNVs were nominally associated with antidepressant response, including 15q13.3 duplications and exonic NRXN1 deletions. These were associated with poor response to antidepressants. Overall burden of CNVs is unlikely to contribute to personalising antidepressant treatment. Specific CNVs associated with antidepressant treatment require replication and further study to confirm their role in the therapeutic action of antidepressant.


Subject(s)
Antidepressive Agents/therapeutic use , DNA Copy Number Variations , Depressive Disorder, Major/drug therapy , Depressive Disorder, Major/genetics , Humans
5.
Am J Med Genet B Neuropsychiatr Genet ; 162B(4): 367-79, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23606572

ABSTRACT

The neuronal glutamate transporter gene SLC1A1 is a candidate gene for obsessive-compulsive disorder (OCD) based on linkage studies and convergent evidence implicating glutamate in OCD etiology. The 3' end of SLC1A1 is the only genomic region with consistently demonstrated OCD association, especially when analyzing male-only probands. However, specific allele associations have not been consistently replicated, and recent OCD genome-wide association and meta-analysis studies have not incorporated all previously associated SLC1A1 SNPs. To clarify the nature of association between SLC1A1 and OCD, pooled analysis was performed on all available relevant raw study data, comprising a final sample of 815 trios, 306 cases and 634 controls. This revealed weak association between OCD and one of nine tested SLC1A1 polymorphisms (rs301443; uncorrected P = 0.046; non-significant corrected P). Secondary analyses of male-affecteds only (N = 358 trios and 133 cases) demonstrated modest association between OCD and a different SNP (rs12682807; uncorrected P = 0.012; non-significant corrected P). Findings of this meta-analysis are consistent with the trend of previous candidate gene studies in psychiatry and do not clarify the putative role of SLC1A1 in OCD pathophysiology. Nonetheless, it may be important to further examine the potential associations demonstrated in this amalgamated sample, especially since the SNPs with modest associations were not included in the more highly powered recent GWAS or in a past meta-analysis including five SLC1A1 polymorphisms. This study underscores the need for much larger sample sizes in future genetic association studies and suggests that next-generation sequencing may be beneficial in examining the potential role of rare variants in OCD.


Subject(s)
Amino Acid Transport System X-AG/genetics , Neurons/metabolism , Obsessive-Compulsive Disorder/genetics , Amino Acid Transport System X-AG/chemistry , Case-Control Studies , Female , Genetic Markers , Humans , Male , Polymorphism, Single Nucleotide
6.
Mol Psychiatry ; 18(2): 195-205, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22182935

ABSTRACT

Meta-analyses of bipolar disorder (BD) genome-wide association studies (GWAS) have identified several genome-wide significant signals in European-ancestry samples, but so far account for little of the inherited risk. We performed a meta-analysis of ∼750,000 high-quality genetic markers on a combined sample of ∼14,000 subjects of European and Asian-ancestry (phase I). The most significant findings were further tested in an extended sample of ∼17,700 cases and controls (phase II). The results suggest novel association findings near the genes TRANK1 (LBA1), LMAN2L and PTGFR. In phase I, the most significant single nucleotide polymorphism (SNP), rs9834970 near TRANK1, was significant at the P=2.4 × 10(-11) level, with no heterogeneity. Supportive evidence for prior association findings near ANK3 and a locus on chromosome 3p21.1 was also observed. The phase II results were similar, although the heterogeneity test became significant for several SNPs. On the basis of these results and other established risk loci, we used the method developed by Park et al. to estimate the number, and the effect size distribution, of BD risk loci that could still be found by GWAS methods. We estimate that >63,000 case-control samples would be needed to identify the ∼105 BD risk loci discoverable by GWAS, and that these will together explain <6% of the inherited risk. These results support previous GWAS findings and identify three new candidate genes for BD. Further studies are needed to replicate these findings and may potentially lead to identification of functional variants. Sample size will remain a limiting factor in the discovery of common alleles associated with BD.


Subject(s)
Bipolar Disorder/ethnology , Bipolar Disorder/genetics , Genetic Predisposition to Disease , Meta-Analysis as Topic , Polymorphism, Single Nucleotide , Ankyrins/genetics , Ankyrins/metabolism , Antidepressive Agents/pharmacology , Asian People/genetics , Cell Line, Transformed , Cytokines/genetics , Dose-Response Relationship, Drug , Female , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , Gene Frequency , Genome-Wide Association Study , Humans , Lectins/genetics , Lectins/metabolism , Lithium Chloride/pharmacology , Male , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , RNA, Messenger/metabolism , Receptors, Prostaglandin/genetics , Receptors, Prostaglandin/metabolism , Time Factors , Valproic Acid/pharmacology , White People/genetics
7.
Mol Psychiatry ; 18(7): 788-98, 2013 Jul.
Article in English | MEDLINE | ID: mdl-22889921

ABSTRACT

Obsessive-compulsive disorder (OCD) is a common, debilitating neuropsychiatric illness with complex genetic etiology. The International OCD Foundation Genetics Collaborative (IOCDF-GC) is a multi-national collaboration established to discover the genetic variation predisposing to OCD. A set of individuals affected with DSM-IV OCD, a subset of their parents, and unselected controls, were genotyped with several different Illumina SNP microarrays. After extensive data cleaning, 1465 cases, 5557 ancestry-matched controls and 400 complete trios remained, with a common set of 469,410 autosomal and 9657 X-chromosome single nucleotide polymorphisms (SNPs). Ancestry-stratified case-control association analyses were conducted for three genetically-defined subpopulations and combined in two meta-analyses, with and without the trio-based analysis. In the case-control analysis, the lowest two P-values were located within DLGAP1 (P=2.49 × 10(-6) and P=3.44 × 10(-6)), a member of the neuronal postsynaptic density complex. In the trio analysis, rs6131295, near BTBD3, exceeded the genome-wide significance threshold with a P-value=3.84 × 10(-8). However, when trios were meta-analyzed with the case-control samples, the P-value for this variant was 3.62 × 10(-5), losing genome-wide significance. Although no SNPs were identified to be associated with OCD at a genome-wide significant level in the combined trio-case-control sample, a significant enrichment of methylation QTLs (P<0.001) and frontal lobe expression quantitative trait loci (eQTLs) (P=0.001) was observed within the top-ranked SNPs (P<0.01) from the trio-case-control analysis, suggesting these top signals may have a broad role in gene expression in the brain, and possibly in the etiology of OCD.


Subject(s)
Genetic Predisposition to Disease/genetics , Genome-Wide Association Study , Nerve Tissue Proteins/genetics , Obsessive-Compulsive Disorder/genetics , Case-Control Studies , Frontal Lobe/metabolism , Humans , Parents , Polymorphism, Single Nucleotide/genetics , Quantitative Trait Loci/genetics , SAP90-PSD95 Associated Proteins , White People/genetics
8.
Mol Psychiatry ; 16(1): 108-20, 2011 Jan.
Article in English | MEDLINE | ID: mdl-19806148

ABSTRACT

Genetic association studies of SLC6A4 (SERT) and obsessive-compulsive disorder (OCD) have been equivocal. We genotyped 1241 individuals in 278 pedigrees from the OCD Collaborative Genetics Study for 13 single-nucleotide polymorphisms, for the linked polymorphic region (LPR) indel with molecular haplotypes at rs25531, for VNTR polymorphisms in introns 2 and 7 and for a 381-bp deletion 3' to the LPR. We analyzed using the Family-Based Association Test (FBAT) under additive, dominant, recessive and genotypic models, using both OCD and sex-stratified OCD as phenotypes. Two-point FBAT analysis detected association between Int2 (P = 0.0089) and Int7 (P = 0.0187) (genotypic model). Sex-stratified two-point analysis showed strong association in females with Int2 (P<0.0002), significant after correction for linkage disequilibrium, and multiple marker and model testing (P(Adj) = 0.0069). The SLC6A4 gene is composed of two haplotype blocks (our data and the HapMap); FBAT whole-marker analysis conducted using this structure was not significant. Several noteworthy nonsignificant results have emerged. Unlike Hu et al., we found no evidence for overtransmission of the LPR L(A) allele (genotype relative risk = 1.11, 95% confidence interval: 0.77-1.60); however, rare individual haplotypes containing L(A) with P<0.05 were observed. Similarly, three individuals (two with OCD/OCPD) carried the rare I425V SLC6A4 variant, but none of them passed it on to their six OCD-affected offspring, suggesting that it is unlikely to be solely responsible for the 'OCD plus syndrome', as reported by Ozaki et al. In conclusion, we found evidence of genetic association at the SLC6A4 locus with OCD. A noteworthy lack of association at the LPR, LPR-rs25531 and rare 425V variants suggests that hypotheses about OCD risk need revision to accommodate these new findings, including a possible gender effect.


Subject(s)
Obsessive-Compulsive Disorder/genetics , Serotonin Plasma Membrane Transport Proteins/genetics , Adolescent , Adult , Child , Female , Genetic Predisposition to Disease , Haplotypes , Humans , Male , Pedigree , Polymorphism, Single Nucleotide , Sex Distribution , United States , Young Adult
13.
Genes Brain Behav ; 5(1): 40-5, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16436187

ABSTRACT

By conferring allele-specific transcriptional activity on the monoamine oxidase A (MAOA) gene in humans, length variation of a repetitive sequence [(variable number of tandem repeat (VNTR)] in the MAOA promoter influences a constellation of personality traits related to aggressive and antisocial behavior and increases the risk of neurodevelopmental and psychiatric disorders. Here, we have analyzed the presence and variability of this MAOA promoter repeat in several species of nonhuman primates. Sequence analysis of MAOA's transcriptional control region revealed the presence of the VNTR in chimpanzee (Pan troglodytes), bonobo (Pan paniscus), gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus), rhesus macaque (Macaca mulatta) and Gelada baboon (Theropithecus gelada). The majority of P. troglodytes and P. paniscus showed a single repeat with a sequence identical to the VNTR sequence in humans. In contrast, analyses of the remaining species revealed shorter sequences similar to the first 18 bp of human VNTR. Compared with other nonhuman primates, the VNTR sequence of M. mulatta showed the highest length variability with allele frequencies of 35, 25 and 40% for the five, six and seven repeat variants, respectively. The extent of variability of the MAOA promoter repeat in both rhesus monkeys and humans supports the notion that there may be a relationship between functional MAOA expression and aggression-related traits in humans and rhesus macaque populations.


Subject(s)
Minisatellite Repeats/physiology , Monoamine Oxidase/genetics , Primates/genetics , Promoter Regions, Genetic/physiology , Animals , Base Sequence , Female , Gene Frequency , Humans , Male , Molecular Sequence Data , Monoamine Oxidase/chemistry , Primates/metabolism , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , Species Specificity , Temperament/physiology
14.
Eukaryot Cell ; 3(6): 1574-88, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15590831

ABSTRACT

Cytoplasmic dynein is a microtubule-associated minus-end-directed motor protein. CaDYN1 encodes the single dynein heavy-chain gene of Candida albicans. The open reading frames of both alleles of CaDYN1 were completely deleted via a PCR-based approach. Cadyn1 mutants are viable but grow more slowly than the wild type. In vivo time-lapse microscopy was used to compare growth of wild-type (SC5314) and dyn1 mutant strains during yeast growth and after hyphal induction. During yeast-like growth, Cadyn1 strains formed chains of cells. Chromosomal TUB1-GFP and HHF1-GFP alleles were used both in wild-type and mutant strains to monitor the orientation of mitotic spindles and nuclear positioning in C. albicans. In vivo fluorescence time-lapse analyses with HHF1-GFP over several generations indicated defects in dyn1 cells in the realignment of spindles with the mother-daughter axis of yeast cells compared to that of the wild type. Mitosis in the dyn1 mutant, in contrast to that of wild-type yeast cells, was very frequently completed in the mother cells. Nevertheless, daughter nuclei were faithfully transported into the daughter cells, resulting in only a small number of multinucleate cells. Cadyn1 mutant strains responded to hypha-inducing media containing l-proline or serum with initial germ tube formation. Elongation of the hyphal tubes eventually came to a halt, and these tubes showed a defect in the tipward localization of nuclei. Using a heterozygous DYN1/dyn1 strain in which the remaining copy was controlled by the regulatable MAL2 promoter, we could switch between wild-type and mutant phenotypes depending on the carbon source, indicating that the observed mutant phenotypes were solely due to deletion of DYN1.


Subject(s)
Candida albicans/genetics , Cell Nucleus/metabolism , Dyneins/genetics , Gene Deletion , Active Transport, Cell Nucleus , Alleles , Candida albicans/metabolism , Cell Movement , Cell Survival , Cytoplasm/metabolism , DNA Primers/chemistry , Genotype , Green Fluorescent Proteins/metabolism , Heterozygote , Microscopy, Fluorescence , Microscopy, Video , Mitosis , Models, Genetic , Mutation , Open Reading Frames , Phenotype , Promoter Regions, Genetic , Recombinant Fusion Proteins/metabolism , Spindle Apparatus/metabolism , Time Factors
15.
Eukaryot Cell ; 3(2): 471-82, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15075276

ABSTRACT

The yeast-to-hypha transition is a key feature in the cell biology of the dimorphic human fungal pathogen Candida albicans. Reorganization of the actin cytoskeleton is required for this dimorphic switch in Candida. We show that C. albicans WAL1 mutants with both copies of the Wiskott-Aldrich syndrome protein (WASP) homolog deleted do not form hyphae under all inducing conditions tested. Growth of the wild-type and wal1 mutant strains was monitored by in vivo time-lapse microscopy both during yeast-like growth and under hypha-inducing conditions. Isotropic bud growth produced round wal1 cells and unusual mother cell growth. Defects in the organization of the actin cytoskeleton resulted in the random localization of actin patches. Furthermore, wal1 cells exhibited defects in the endocytosis of the lipophilic dye FM4-64, contained increased numbers of vacuoles compared to the wild type, and showed defects in bud site selection. Under hypha-inducing conditions wal1 cells were able to initiate polarized morphogenesis, which, however, resulted in the formation of pseudohyphal cells. Green fluorescent protein (GFP)-tagged Wal1p showed patch-like localization in emerging daughter cells during the yeast growth phase and at the hyphal tips under hypha-inducing conditions. Wal1p-GFP localization largely overlapped with that of actin. Our results demonstrate that Wal1p is required for the organization of the actin cytoskeleton and hyphal morphogenesis in C. albicans as well as for endocytosis and vacuole morphology.


Subject(s)
Candida albicans/growth & development , Fungal Proteins/physiology , Proteins/physiology , Actins/metabolism , Amino Acid Sequence , Candida albicans/cytology , Candida albicans/genetics , Cell Cycle , Cell Polarity , Cell Wall/ultrastructure , Endocytosis , Fungal Proteins/genetics , Hyphae/growth & development , Hyphae/ultrastructure , Microscopy, Fluorescence , Molecular Sequence Data , Mutation , Proteins/genetics , Proteins/metabolism , Pyridinium Compounds/analysis , Pyridinium Compounds/metabolism , Quaternary Ammonium Compounds/analysis , Quaternary Ammonium Compounds/metabolism , Sequence Alignment , Vacuoles/ultrastructure , Wiskott-Aldrich Syndrome Protein
16.
Fungal Genet Biol ; 40(1): 65-71, 2003 Oct.
Article in English | MEDLINE | ID: mdl-12948514

ABSTRACT

We have developed a transformation system for the dimorphic plant pathogenic fungus Holleya sinecauda based on an electroporation protocol used for the closely related filamentous fungus Ashbya gossypii. DNA-mediated transformation of the dominant selection marker kanMX generated H. sinecauda transformants that were resistant to the antibiotic drug G418/geneticin. Freely replicating plasmids could be established in H. sinecauda using an A. gossypii autonomously replicating sequence (ARS) element, whereas Saccharomyces cerevisiae ARS elements, which are functional in A. gossypii, were not functional in H. sinecauda. In addition, centromeric DNA of A. gossypii stabilized the maintenance of plasmids in H. sinecauda under non-selective conditions. We isolated a fragment of the HsLEU2 gene and used this locus for targeted integration of kanMX3, consisting of the kanMX gene flanked by direct repeats. This allowed the construction of a Hsleu2 strain which became G418 sensitive after direct repeat-induced marker excision. The Hsleu2 strain can be complemented by the ScLEU2 gene. Finally, we constructed high- and low-copy shuttle vectors for H. sinecauda.


Subject(s)
Saccharomycetales/genetics , Sex Characteristics , Transformation, Genetic , DNA, Fungal/chemistry , DNA, Fungal/genetics , Electroporation , Genetic Markers , Genome, Fungal , Gentamicins , Kanamycin Resistance , Molecular Sequence Data , Open Reading Frames/genetics , Plants/microbiology , Plasmids/genetics , Promoter Regions, Genetic , Recombination, Genetic
17.
Fungal Genet Biol ; 34(2): 63-82, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11686673

ABSTRACT

Fungi generally display either of two growth modes, yeast-like or filamentous, whereas dimorphic fungi, upon environmental stimuli, are able to switch between the yeast-like and the filamentous growth mode. Signal transduction pathways have been elucidated in the budding yeast Saccharomyces cerevisiae, establishing a morphogenetic network that links cell-cycle events with cellular morphogenesis. Recent molecular genetic studies in several filamentous fungal model systems revealed key components required for distinct steps from fungal spore germination to the maintenance of polar hyphal growth, mycelium formation, and nuclear division. This allows a mechanistic comparison of yeast-like and hyphal growth and the establishment of a core model morphogenetic network for filamentous growth including signaling via the cAMP pathway, Rho modules, and cell cycle kinases. Appreciating similarities between morphogenetic networks of the unicellular yeasts and the multicellular filamentous fungi will open new research directions, help in isolating the central network components, and ultimately pave the way to elucidate the central differences (of many) that distinguish, e.g., the growth mode of filamentous fungi from that of their yeast-like relatives, the role of cAMP signaling, and nuclear division.


Subject(s)
Hyphae/physiology , Yeasts/cytology , Yeasts/physiology , Aspergillus/cytology , Aspergillus/physiology , Cell Division/physiology , Cell Polarity , Cyclic AMP/metabolism , Cytoskeleton/physiology , Hyphae/cytology , Hyphae/growth & development , Morphogenesis/physiology , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/physiology , Signal Transduction/physiology , Spores, Fungal/physiology
18.
Genetics ; 157(2): 601-10, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11156982

ABSTRACT

Polarized cell growth requires a polarized organization of the actin cytoskeleton. Small GTP-binding proteins of the Rho-family have been shown to be involved in the regulation of actin polarization as well as other processes. Hyphal growth in filamentous fungi represents an ideal model to investigate mechanisms involved in generating cell polarity and establishing polarized cell growth. Since a potential role of Rho-proteins has not been studied so far in filamentous fungi we isolated and characterized the Ashbya gossypii homologs of the Saccharomyces cerevisiae CDC42, CDC24, RHO1, and RHO3 genes. The AgCDC42 and AgCDC24 genes can both complement conditional mutations in the S. cerevisiae CDC42 and CDC24 genes and both proteins are required for the establishment of actin polarization in A. gossypii germ cells. Agrho1 mutants show a cell lysis phenotype. Null mutant strains of Agrho3 show periodic swelling of hyphal tips that is overcome by repolarization and polar hyphal growth in a manner resembling the germination pattern of spores. Thus different Rho-protein modules are required for distinct steps during polarized hyphal growth of A. gossypii.


Subject(s)
Cell Division/genetics , Guanine Nucleotide Exchange Factors , Saccharomyces cerevisiae Proteins , Saccharomycetales/genetics , rho GTP-Binding Proteins/physiology , Actins/genetics , Actins/metabolism , Amino Acid Sequence , Cell Cycle Proteins/genetics , Cytoskeleton/genetics , Cytoskeleton/metabolism , DNA/metabolism , DNA Primers/metabolism , Gene Deletion , Genetic Complementation Test , Models, Genetic , Molecular Sequence Data , Mutagenesis , Mutation , Phenotype , Proto-Oncogene Proteins/genetics , Saccharomyces cerevisiae/genetics , Sequence Homology, Amino Acid , cdc42 GTP-Binding Protein/genetics , cdc42 GTP-Binding Protein/physiology , rho GTP-Binding Proteins/genetics
19.
Eur J Neurosci ; 12(10): 3560-6, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11029625

ABSTRACT

The heat-transducing receptor VR1 cloned from rat sensory neurons can be activated by both noxious heat and capsaicin. As the response of sensory neurons to capsaicin is species dependent, it is conceivable that the responses to noxious heat and to capsaicin are transduced by distinct receptors across different species. Therefore, we investigated responses to noxious heat from a capsaicin-insensitive (chick) and a capsaicin-sensitive (rat) species. In chick, whole-cell patch-clamp experiments in isolated dorsal root ganglion neurons revealed two populations of neurons with different thresholds to noxious heat, activated at approximately 43 degrees C and approximately 53 degrees C. In cobalt uptake experiments, the proportion of neurons showing a heat-induced response increased with increasing heat stimuli. Application of capsaicin (1-10 microM) did not result in inward currents or cobalt uptake. Rat neurons yielded comparable results in heat experiments, but were capsaicin-sensitive. Although chick neurons are insensitive to capsaicin, the competitive capsaicin antagonist capsazepine (1-10 microM) was effective in blocking heat-induced responses, verified by patch-clamp and cobalt uptake methods. The noncompetitive capsaicin antagonist ruthenium red (10 microM) reduced to almost nil the proportion of heat-responsive neurons identified with the cobalt uptake method. These findings suggest that chick DRG neurons express a low-threshold heat-transducing receptor with a pharmacological profile distinct from the low-threshold heat receptor VR1 cloned from rat DRG neurons. The data support the idea that there might be heat receptor subtypes with differences in the capsaicin binding site.


Subject(s)
Capsaicin/analogs & derivatives , Capsaicin/antagonists & inhibitors , Ganglia, Spinal/drug effects , Hot Temperature/adverse effects , Neurons, Afferent/drug effects , Nociceptors/drug effects , Thermosensing/physiology , Animals , Capsaicin/pharmacology , Cell Size/physiology , Cells, Cultured , Chickens/anatomy & histology , Chickens/metabolism , Cobalt/metabolism , Cobalt/pharmacology , Ganglia, Spinal/cytology , Ganglia, Spinal/metabolism , Ion Channels/drug effects , Ion Channels/metabolism , Male , Neurons, Afferent/cytology , Neurons, Afferent/metabolism , Nociceptors/cytology , Nociceptors/metabolism , Patch-Clamp Techniques , Rats , Rats, Sprague-Dawley , Ruthenium Red/pharmacology
20.
J Cell Sci ; 113 ( Pt 9): 1611-21, 2000 May.
Article in English | MEDLINE | ID: mdl-10751152

ABSTRACT

In the filamentous ascomycete Ashbya gossypii, like in other filamentous fungi onset of growth in dormant spores occurs as an isotropic growth phase generating spherical germ cells. Thereafter, a switch to polarized growth results in the formation of the first hyphal tip. The initial steps of hyphal tip formation in filamentous fungi, therefore, resemble processes taking place prior to and during bud emergence of unicellular yeast-like fungi. We investigated whether phenotypic similarities between these distinct events extended to the molecular level. To this end we isolated and characterized the A. gossypii homolog of the Saccharomyces cerevisiae BEM2 gene which is part of a network of rho-GTPases and their regulators required for bud emergence and bud growth in yeast. Here we show that the AgBem2 protein contains a GAP- (GTPase activating protein) domain for rho-like GTPases at its carboxy terminus, and that this part of AgBem2p is required for complementation of an Agbem2 null strain. Germination of spores resulted in enlarged Agbem2 germ cells that were unable to generate the bipolar branching pattern found in wild-type germ cells. In addition, mutant hyphae were swollen due to defects in polarized cell growth indicated by the delocalized distribution of chitin and cortical actin patches. Surprisingly, the complete loss of cell polarity which lead to spherical hyphal tips was overcome by the establishment of new cell polarities and the formation of multiple new hyphal tips. In conclusion these results and other findings demonstrate that establishment of cell polarity, maintenance of cell polarity, and polarized hyphal growth in filamentous fungi require members of &rgr;-GTPase modules.


Subject(s)
Ascomycota/cytology , GTPase-Activating Proteins , Saccharomyces cerevisiae Proteins , Spores, Fungal , rho GTP-Binding Proteins/physiology , Amino Acid Sequence , Ascomycota/genetics , Ascomycota/growth & development , Base Sequence , DNA Primers , Fungal Proteins/chemistry , Fungal Proteins/genetics , Molecular Sequence Data , Sequence Deletion , Sequence Homology, Amino Acid , rho GTP-Binding Proteins/chemistry
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