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C Bouchier

Publications and source records attributed to C Bouchier.

18 recordsLinked to original sources
PubMed2003

Collaborative consensus for optimized multilocus sequence typing of Candida albicans.

A panel of 86 different Candida albicans isolates was subjected to multilocus sequence typing (MLST) in two laboratories to obtain sequence data for 10 published housekeeping gene fragments. Analysis of data for all possible combinations of five, six, seven, eight, and nine of the fragments showed that a set comprising the fragments AAT1a, ACC1, ADP1, MPIb, SYA1, VPS13, and ZWF1b was the smallest that yielded 86 unique diploid sequence types for the 86 isolates. This set is recommended for future MLST with C. albicans.

Candida albicans↗
PubMed2003

Expanding the phenotype of LMNA mutations in dilated cardiomyopathy and functional consequences of these mutations.

AIMS: Mutations in the lamin A/C gene (LMNA) have been reported to be involved in dilated cardiomyopathy (DCM) associated with conduction system disease and/or skeletal myopathy. The aim of this study was to perform a mutational analysis of LMNA in a large white population of patients affected by dilated cardiomyopathy with or without associated symptoms. METHODS: We performed screening of the coding sequence of LMNA on DNA samples from 66 index cases, and carried out cell transfection experiments to examine the functional consequences of the mutations identified. RESULTS: A new missense (E161K) mutation was identified in a family with early atrial fibrillation and a previously described (R377H) mutation in another family with a quadriceps myopathy associated with DCM. A new mutation (28insA) leading to a premature stop codon was identified in a family affected by DCM with conduction defects. No mutation in LMNA was found in cases with isolated dilated cardiomyopathy. Functional analyses have identified potential physiopathological mechanisms involving identified mutations, such as haploinsufficiency (28insA) or intermediate filament disorganisation (E161K, R377H). CONCLUSION: For the first time, a specific phenotype characterised by early atrial fibrillation is associated with LMNA mutation. Conversely, mutations in LMNA appear as a rare cause of isolated dilated cardiomyopathy. The variable phenotypes observed in LMNA-DCM might be explained by the variability of functional consequences of LMNA mutations.

Adolescent↗
PubMed2000

A new locus for autosomal dominant dilated cardiomyopathy identified on chromosome 6q12-q16.

Dilated cardiomyopathy (DCM) is a heart-muscle disease characterized by ventricular dilatation and impaired heart contraction and is heterogeneous both clinically and genetically. To date, 12 candidate disease loci have been described for autosomal dominant DCM. We report the identification of a new locus on chromosome 6q12-16 in a French family with 9 individuals affected by the pure form of autosomal dominant DCM. This locus was found by using a genomewide search after exclusion of all reported disease loci and genes for DCM. The maximum pairwise LOD score was 3.52 at recombination fraction 0.0 for markers D6S1644 and D6S1694. Haplotype construction delineated a region of 16.4 cM between markers D6S1627 and D6S1716. This locus does not overlap with two other disease loci that have been described in nonpure forms of DCM and have been mapped on 6q23-24 and 6q23. The phospholamban, malic enzyme 1-soluble, and laminin-alpha4 genes were excluded as candidate genes, using single-strand conformation polymorphism or linkage analysis.

Adolescent↗
PubMed2000

Epidemiology of desmin and cardiac actin gene mutations in a european population of dilated cardiomyopathy.

AIMS: Although dilated cardiomyopathy is the most frequent form of cardiomyopathy, its aetiology is still poorly understood. In about 20-30% of cases the disease is familial with a large predominance of autosomal dominant transmission. Ten different chromosomal loci have been described for autosomal dominant forms of dilated cardiomyopathy. Only two genes have been associated with pure forms (without myopathy and/or conduction disorders) of the disease, the cardiac actin and the desmin genes. Our aim was to determine the proportion of dilated cardiomyopathy affected individuals carrying a mutation in one of these two genes. METHODS AND RESULTS: We performed (1) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of cardiac actin on DNA samples from 43 probands of dilated cardiomyopathy families and 43 sporadic cases; (2) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of desmin combined with a search for the described missense mutation (Ile451Met) by restriction fragment length polymorphism analysis on DNA samples from 41 probands of dilated cardiomyopathy families and 22 sporadic cases. CONCLUSION: None of the patients presents a mutation in any of these two genes. Consequently, the proportion of European dilated cardiomyopathy affected individuals bearing a mutation in (1) the cardiac actin gene is less than 1.2%, (2) the desmin gene is less than 1.6%.

Actins↗
PubMed1999

Mutations in ribosomal protein S19 gene and diamond blackfan anemia: wide variations in phenotypic expression.

Mutations of the ribosomal protein S19 (RPS19) gene were recently identified in 10 patients with Diamond Blackfan anemia (DBA). To determine the prevalence of mutations in this gene in DBA and to begin to define the molecular basis for the observed variable clinical phenotype of this disorder, the genomic sequence of the 6 exons and the 5' untranslated region of the RPS19 gene was directly assessed in DBA index cases from 172 new families. Mutations affecting the coding sequence of RPS19 or splice sites were found in 34 cases (19.7%), whereas mutations in noncoding regions were found in 8 patients (4.6%). Mutations included nonsense, missense, splice sites, and frameshift mutations. A hot spot for missense mutations was identified between codons 52 and 62 of the RPS19 gene in a new sequence consensus motif W-[YFW]-[YF]-x-R-[AT]-A-[SA]-x-[AL]-R-[HRK]-[ILV]-Y. No correlation between the nature of mutations and the different patterns of clinical expression, including age at presentation, presence of malformations, and therapeutic outcome, could be documented. Moreover, RPS19 mutations were also found in some first-degree relatives presenting only with isolated high erythrocyte adenosine deaminase activity and/or macrocytosis. The lack of a consistent relationship between the nature of the mutations and the clinical phenotype implies that yet unidentified factors modulate the phenotypic expression of the primary genetic defect in families with RPS19 mutations.

Adolescent↗
PubMed1999

Abnormal restriction pattern of PIP gene associated with human primary prostate cancers.

The PIP gene, localized in the 7q34 region that contains a number of fragile sites such as FRA 7H and FRA TI, codes for gp17/PIP, a protein secreted by breast apocrine tumors. We analyzed the integrity of this gene in 20 tumors of the urogenital tract. We found rearranged EcoRI fragments in 5 of 15 primary prostate carcinomas. No rearrangement was found in normal prostates derived from five patients undergoing prostatocystectomy during treatment of bladder cancers. By Southern blot hybridization with PIP gene exon-specific probes, the rearrangements were mapped at or near the 3' end of the gene. These abnormalities were found, not only in the neoplastic cells invading the prostatic tissues, but also in seminal vesicles without histologic tumoral features. These data suggest a critical role of the PIP gene or neighboring genes in prostate cancer.

Apolipoproteins↗
PubMed1998

New susceptibility locus for rheumatoid arthritis suggested by a genome-wide linkage study.

Rheumatoid arthritis (RA), the most common autoimmune disease, is associated in families with other autoimmune diseases, including insulin-dependent diabetes mellitus (IDDM). Its genetic component has been suggested by familial aggregation (lambdas = 5), twin studies, and segregation analysis. HLA, which is the only susceptibility locus known, has been estimated to account for one-third of this component. The aim of this paper was to identify new RA loci. A genome scan was performed with 114 European Caucasian RA sib pairs from 97 nuclear families. Linkage was significant only for HLA (P < 2.5.10(-5)) and nominal for 19 markers in 14 other regions (P < 0.05). Four of the loci implicated in IDDM potentially overlap with these regions: the putative IDDM6, IDDM9, IDDM13, and DXS998 loci. The first two of these candidate regions, defined in the RA genome scan by the markers D18S68-D18S61-D18S469 (18q22-23) and D3S1267 (3q13), respectively, were studied in 194 additional RA sib pairs from 164 nuclear families. Support for linkage to chromosome 3 only was extended significantly (P = 0.002). The analysis of all 261 families provided a linkage evidence of P = 0. 001 and suggested an interaction between this putative RA locus and HLA. This locus could account for 16% of the genetic component of RA. Candidate genes include those coding for CD80 and CD86, molecules involved in antigen-specific T cell recognition. In conclusion, this first genome scan in RA Caucasian families revealed 14 candidate regions, one of which was supported further by the study of a second set of families.

Arthritis, Rheumatoid↗
PubMed1995

[IMAGE: molecular integration of the analysis of the human genome and its expression].

We have developed an integrated approach for the analysis of human cDNA libraries from neuromuscular tissues, based on the acquisition of primary structural, expression and mapping data. 26,938 sequence signatures (over 7 million bases) have been derived from both ends of skeletal muscle and brain cDNA clones. Primary redundancy analysis and classification of database similarities made it possible to characterize by structural data about 8,000 human gene transcripts, the majority of which is catalogued for the first time. Collecting hybridization signatures of complex cDNA probes derived from the tissues of origin to cDNA clones arrayed on high density filters provided a global and quantifiable view of the complexity and level of expression of the different transcripts. The development of 2,792 eSTS markers amplifiable by PCR defined the chromosomal localization of some 2,500 genes corresponding to the transcripts sequenced. The data collected are part of the corpus of the human gene transcript catalog and the genic map of the human genome.

Brain Chemistry↗
PubMed1994

The origin of the diversity of crotoxin isoforms in the venom of Crotalus durissus terrificus.

Crotoxin, the main toxin from the venom of the South American rattlesnake Crotalus durissus terrificus, is a beta-neurotoxin which consists of the non-covalent association of two subunits: a phospholipase A2 subunit B (CB), and a non-enzymic subunit A (CA). We have previously purified and characterized several isoforms of each subunit of crotoxin in the venom collected from numerous snakes. Furthermore, three cDNAs encoding two CB isoforms and the precursor, pro-CA, of subunit A have been isolated from a cDNA library prepared from a single venom gland of Crotalus durissus terrificus. The aim of this study is to analyse an individual snake venom from an animal that has been used to construct a cDNA library. Several isoforms of subunit A and two isoforms of subunit B were isolated and compared to purified and characterized subunit isoforms from pooled venom. The result of this study showed that the multiplicity and the diversity of crotoxin isoforms result from post-translational modifications occurring on a precursor and from the expression of different messenger RNAs present in an individual snake. It allowed for the identification of the two CB isoforms encoding cDNAs expressed in the individual venom with two isoforms from pooled venom, CBc and probably CBa2, that belong to two classes of crotoxin complexes which can be distinguished biochemically and pharmacologically.

Amino Acid Sequence↗
PubMed1991

Notechis 11'2, a non-toxic phospholipase A2 from the venom of Notechis scutatus scutatus.

Previously, we deduced the amino acid sequence of a novel phospholipase-A2-like protein (PLA2) from the nucleotide sequence of a cDNA isolated from a library prepared from the venom gland of the Australian elapid Notechis scutatus scutatus. The corresponding protein has now been identified, purified from the venom and named Notechis 11'2. Its complete amino acid sequence has been determined by automated Edman degradation of both the whole protein and peptides generated by Staphylococcus aureus protease digestion and chemical cleavage at a tryptophan residue. As predicted from its sequence which contains all the residues putatively required for PLA2 activity, Notechis 11'2 exhibits an esterase activity, preferentially against neutral phospholipids. However, despite its sequence homology with other highly toxic PLA2 present in the venom of Notechis scutatus scutatus, notechis 11'2 has no lethal activity. This observation further supports the view that the lethal activity of PLA2 from Notechis scutatus scutatus is not due to the esterasic activity only.

Amino Acid Sequence↗
PubMed1991

Analysis of cDNAs encoding the two subunits of crotoxin, a phospholipase A2 neurotoxin from rattlesnake venom: the acidic non enzymatic subunit derives from a phospholipase A2-like precursor.

We report the sequences of three cDNAs encoding the two subunits (CA and CB) of crotoxin, a neurotoxic phospholipase A2 from the venom of the South-American rattlesnake Crotalus durissus terrificus. CB is a basic and toxic phospholipase A2 and CA is an acidic, non toxic and non enzymatic three chain containing protein which enhances the lethal potency of CB. Two cDNAs encoding precursors of CB isoforms have been isolated from a cDNA library prepared from one venom gland. Both precursors are made of the same 16 residues signal peptide followed by a polypeptide of 122 amino acid residues. The two mature sequences differ from each other at eight positions and are in good agreement with the previous polypeptide sequence reported for CB. In the case of CA, the cDNA encodes a signal peptide identical to those found in CB precursors, followed by a polypeptide of 122 amino acids clearly homologous to phospholipases A2 and including three regions which correspond to the three chains of mature CA. This demonstrates that CA is generated from a phospholipase A2-like precursor, called pro-CA, by the removal of three peptides, leaving unchanged the molecule core cross-linked by disulfide bridges. The 5'-untranslated tracts of cDNAs encoding CA and CB are nearly identical and the 3'-untranslated tracts are very similar, suggesting that the mRNAs encoding the two crotoxin subunits may result from the alternative splicing of a single gene or from the existence of a recent gene conversion. Data have been analysed in light of recent results on other phospholipases A2 from different origins.

Amino Acid Sequence↗
PubMed1989

Crotoxin, half-century of investigations on a phospholipase A2 neurotoxin.

Crotoxin, the major toxic component of the South American rattlesnake, Crotalus durissus terrificus, is a neurotoxic phospholipase A2 which exerts its pathophysiological action by blocking the neuromuscular transmission. Crotoxin acts primarily by altering the acetylcholine release from the nerves terminals through a mechanism which has not yet been elucidated. It also acts on postsynaptic membranes by stabilizing the acetylcholine receptor in an inactive conformation very similar to the desensitized state. Crotoxin is made of two dissimilar subunits: a basic and weakly toxic phospholipase A2 component-B, and an acidic and non toxic component-A which does not possess any enzymatic activity. Binding experiments showed that crotoxin subunits dissociate when crotoxin interacts with biological membranes: Component-B binds, whereas component-A appears free in solution. The phospholipase A2 subunit binds in a non saturable, non specific manner, on any kind of biological membranes, whereas in the presence of component-A it interacts only with a limited number of high affinity binding sites present on synaptic membranes but not on erythrocyte membranes. Although the target site (acceptor) of crotoxin has not yet been formally identified, binding experiments carried out with small unilamellar phospholipid vesicles of different compositions indicate that some negatively charged phospholipids like mono and diphosphoinositide phosphates might be an important component of crotoxin acceptor site. Crotoxin is in fact a mixture of several isoforms which have very similar but not identical polypeptide sequences. An individual Crotalus durissus terrificus snake is able to synthesize several crotoxin isoforms which may result of the expression of several isogenes and/or of post-translational events. When compared in quantitative manner, the crotoxin isoforms slightly but significantly differ in their enzymatic and pharmacological properties. Finally, immunochemical investigations carried out with polyclonal antibodies prepared against both crotoxin subunits, showed that non precipitating anti-component-B- antibodies (Fab) inhibit the phospholipase A2 activity of crotoxin and neutralize its lethal potency, suggesting that the catalytic and toxic sites of crotoxin are closely related.

Crotoxin↗