Biomedical subjects

E Bon

Publications and source records attributed to E Bon.

At least 19 recordsLinked to original sources

PubMed2005

CYGD: the Comprehensive Yeast Genome Database.

The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, chosen as the best understood model organism for eukaryotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual genes and proteins. In addition, it provides information on the physical and functional interactions among proteins as well as other genetic elements. These cellular networks include metabolic and regulatory pathways, signal transduction and transport processes as well as co-regulated gene clusters. As more yeast genomes are published, their annotation becomes greatly facilitated using S.cerevisiae as a reference. CYGD provides a way of exploring related genomes with the aid of the S.cerevisiae genome as a backbone and SIMAP, the Similarity Matrix of Proteins. The comprehensive resource is available under http://mips.gsf.de/genre/proj/yeast/.

Binding Sites↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 1. A set of yeast species for molecular evolution studies.

The identification of molecular evolutionary mechanisms in eukaryotes is approached by a comparative genomics study of a homogeneous group of species classified as Hemiascomycetes. This group includes Saccharomyces cerevisiae, the first eukaryotic genome entirely sequenced, back in 1996. A random sequencing analysis has been performed on 13 different species sharing a small genome size and a low frequency of introns. Detailed information is provided in the 20 following papers. Additional tables available on websites describe the ca. 20000 newly identified genes. This wealth of data, so far unique among eukaryotes, allowed us to examine the conservation of chromosome maps, to identify the 'yeast-specific' genes, and to review the distribution of gene families into functional classes. This project conducted by a network of seven French laboratories has been designated 'Génolevures'.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 3. Methods and strategies used for sequence analysis and annotation.

The primary analysis of the sequences for our Hemiascomycete random sequence tag (RST) project was performed using a combination of classical methods for sequence comparison and contig assembly, and of specifically written scripts and computer visualization routines. Comparisons were performed first against DNA and protein sequences from Saccharomyces cerevisiae, then against protein sequences from other completely sequenced organisms and, finally, against protein sequences from all other organisms. Blast alignments were individually inspected to help recognize genes within our random genomic sequences despite the fact that only parts of them were available. For each yeast species, validated alignments were used to infer the proper genetic code, to determine codon usage preferences and to calculate their degree of sequence divergence with S. cerevisiae. The quality of each genomic library was monitored from contig analysis of the DNA sequences. Annotated sequences were submitted to the EMBL database, and the general annotation tables produced served as a basis for our comparative description of the evolution, redundancy and function of the Hemiascomycete genomes described in other articles of this issue.

Amino Acid Sequence↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 4. The genome of Saccharomyces cerevisiae revisited.

Since its completion more than 4 years ago, the sequence of Saccharomyces cerevisiae has been extensively used and studied. The original sequence has received a few corrections, and the identification of genes has been completed, thanks in particular to transcriptome analyses and to specialized studies on introns, tRNA genes, transposons or multigene families. In order to undertake the extensive comparative sequence analysis of this program, we have entirely revisited the S. cerevisiae sequence using the same criteria for all 16 chromosomes and taking into account publicly available annotations for genes and elements that cannot be predicted. Comparison with the other yeast species of this program indicates the existence of 50 novel genes in segments previously considered as 'intergenic' and suggests extensions for 26 of the previously annotated genes.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 5. Saccharomyces bayanus var. uvarum.

Saccharomyces bayanus var. uvarum investigated here is the species closest to Saccharomyces cerevisiae. Random sequence tags (RSTs) allowed us to identify homologues to 2789 open reading frames (ORFs) in S. cerevisiae, ORFs duplicated in S. uvarum but not in S. cerevisiae, centromeres, tRNAs, homologues of Ty1/2 and Ty4 retrotransposons, and a complete rDNA repeat. Only 13 RSTs seem to be homologous to sequences in other organisms but not in S. cerevisiae. As the synteny between the two species is very high, cases in which synteny is lost suggest special mechanisms of genome evolution. The corresponding RSTs revealed that S. uvarum can exist without any S. cerevisiae DNA introgression. Accession numbers are from AL397139 to AL402278 in the EMBL databank.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 6. Saccharomyces exiguus.

Random sequence tags were obtained from a genomic DNA library of Saccharomyces exiguus. The mitochondrial genome appeared to be at least 25.7 kb in size, with a different organization compared to Saccharomyces cerevisiae. An unusual putative 953 bp long terminal repeated element associated to Ty3 was found. A set of 1451 genes was identified homologous to S. cerevisiae open reading frames. Only five genes were identified outside the S. cerevisiae taxon, confirming that S. exiguus is phylogenetically closely related to S. cerevisiae. Unexpectedly, numerous duplicated genes were found whereas they are unique in S. cerevisiae. The sequences are deposited at EMBL under the accession numbers: AL407377-AL409955.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 7. Saccharomyces servazzii.

The genome of Saccharomyces servazzii was analyzed with 2570 random sequence tags totalling 2.3 Mb. BLASTX comparisons revealed a minimum of 1420 putative open reading frames with significant homology to Saccharomyces cerevisiae (58% aa identity on average), two with Schizosaccharomyces pombe and one with a human protein, confirming that S. servazzii is closely related to S. cerevisiae. About 25% of the S. servazzii genes were identified, assuming that the gene complement is identical in both yeasts. S. servazzii carries very few transposable elements related to Ty elements in S. cerevisiae. Most of the mitochondrial genes were identified in eight contigs altogether spanning 25 kb for a predicted size of 29 kb. A significant match with the Kluyveromyces lactis linear DNA plasmid pGKL-1 encoded RF4 killer protein suggests that a related plasmid exists in S. servazzii. The sequences have been deposited with EMBL under the accession numbers AL402279-AL404848.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 9. Saccharomyces kluyveri.

The genome of Saccharomyces kluyveri was explored through 2528 random sequence tags with an average length of 981 bp. The complete nuclear ribosomal DNA unit was found to be 8656 bp in length. Sequences homologous to retroelements of the gypsy and copia types were identified as well as numerous solo long terminal repeats. We identified at least 1406 genes homologous to Saccharomyces cerevisiae open reading frames, with on average 58.1% and 72.4% amino acid identity and similarity, respectively. In addition, by comparison with completely sequenced genomes and the SwissProt database, we found 27 novel S. kluyveri genes. Most of these genes belong to pathways or have functions absent from S. cerevisiae, such as the catabolic pathway of purines or pyrimidines, melibiose fermentation, sorbitol utilization, or degradation of pollutants. The sequences are deposited in EMBL under the accession numbers AL404849-AL407376.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 14. Debaryomyces hansenii var. hansenii.

By analyzing 2830 random sequence tags (RSTs), totalling 2.7 Mb, we explored the genome of the marine, osmo- and halotolerant yeast, Debaryomyces hansenii. A contig 29 kb in length harbors the entire mitochondrial genome. The genes encoding Cox1, Cox2, Cox3, Cob, Atp6, Atp8, Atp9, several subunits of the NADH dehydrogenase complex 1 and 11 tRNAs were unambiguously identified. An equivalent number of putative transposable elements compared to Saccharomyces cerevisiae were detected, the majority of which are more related to higher eukaryote copia elements. BLASTX comparisons of RSTs with databases revealed at least 1119 putative open reading frames with homology to S. cerevisiae and 49 to other genomes. Specific functions, including transport of metabolites, are clearly over-represented in D. hansenii compared to S. cerevisiae, consistent with the observed difference in physiology of the two species. The sequences have been deposited with EMBL under the accession numbers AL436045-AL438874.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 17. Yarrowia lipolytica.

A total of 4940 random sequence tags of the dimorphic yeast Yarrowia lipolytica, totalling 4.9 Mb, were analyzed. BLASTX comparisons revealed at least 1229 novel Y. lipolytica genes 1083 genes having homology with Saccharomyces cerevisiae genes and 146 with genes from various other genomes. This confirms the rapid sequence evolution assumed for Y. lipolytica. Functional analysis of newly discovered genes revealed that several enzymatic activities were increased compared to S. cerevisiae, in particular, transport activities, ion homeostasis, and various metabolism pathways. Most of the mitochondrial genes were identified in contigs spanning more than 47 kb. Matches to retrotransposons were observed, including a S. cerevisiae Ty3 and a LINE element. The sequences have been deposited with EMBL under the accession numbers AL409956-AL414895.

DNA Transposable Elements↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 18. Comparative analysis of chromosome maps and synteny with Saccharomyces cerevisiae.

We have analyzed the evolution of chromosome maps of Hemiascomycetes by comparing gene order and orientation of the 13 yeast species partially sequenced in this program with the genome map of Saccharomyces cerevisiae. From the analysis of nearly 8000 situations in which two distinct genes having homologs in S. cerevisiae could be identified on the sequenced inserts of another yeast species, we have quantified the loss of synteny, the frequency of single gene deletion and the occurrence of gene inversion. Traces of ancestral duplications in the genome of S. cerevisiae could be identified from the comparison with the other species that do not entirely coincide with those identified from the comparison of S. cerevisiae with itself. From such duplications and from the correlation observed between gene inversion and loss of synteny, a model is proposed for the molecular evolution of Hemiascomycetes. This model, which can possibly be extended to other eukaryotes, is based on the reiteration of events of duplication of chromosome segments, creating transient merodiploids that are subsequently resolved by single gene deletion events.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 19. Ascomycetes-specific genes.

Comparisons of the 6213 predicted Saccharomyces cerevisiae open reading frame (ORF) products with sequences from organisms of other biological phyla differentiate genes commonly conserved in evolution from 'maverick' genes which have no homologue in phyla other than the Ascomycetes. We show that a majority of the 'maverick' genes have homologues among other yeast species and thus define a set of 1892 genes that, from sequence comparisons, appear 'Ascomycetes-specific'. We estimate, retrospectively, that the S. cerevisiae genome contains 5651 actual protein-coding genes, 50 of which were identified for the first time in this work, and that the present public databases contain 612 predicted ORFs that are not real genes. Interestingly, the sequences of the 'Ascomycetes-specific' genes tend to diverge more rapidly in evolution than that of other genes. Half of the 'Ascomycetes-specific' genes are functionally characterized in S. cerevisiae, and a few functional categories are over-represented in them.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 20. Evolution of gene redundancy compared to Saccharomyces cerevisiae.

We have evaluated the degree of gene redundancy in the nuclear genomes of 13 hemiascomycetous yeast species. Saccharomyces cerevisiae singletons and gene families appear generally conserved in these species as singletons and families of similar size, respectively. Variations of the number of homologues with respect to that expected affect from 7 to less than 24% of each genome. Since S. cerevisiae homologues represent the majority of the genes identified in the genomes studied, the overall degree of gene redundancy seems conserved across all species. This is best explained by a dynamic equilibrium resulting from numerous events of gene duplication and deletion rather than by a massive duplication event occurring in some lineages and not in others.

Ascomycota↗

PubMed2000

Genomic exploration of the hemiascomycetous yeasts: 21. Comparative functional classification of genes.

We explored the biological diversity of hemiascomycetous yeasts using a set of 22000 newly identified genes in 13 species through BLASTX searches. Genes without clear homologue in Saccharomyces cerevisiae appeared to be conserved in several species, suggesting that they were recently lost by S. cerevisiae. They often identified well-known species-specific traits. Cases of gene acquisition through horizontal transfer appeared to occur very rarely if at all. All identified genes were ascribed to functional classes. Functional classes were differently represented among species. Species classification by functional clustering roughly paralleled rDNA phylogeny. Unequal distribution of rapidly evolving, ascomycete-specific, genes among species and functions was shown to contribute strongly to this clustering. A few cases of gene family amplification were documented, but no general correlation could be observed between functional differentiation of yeast species and variations of gene family sizes. Yeast biological diversity seems thus to result from limited species-specific gene losses or duplications, and for a large part from rapid evolution of genes and regulatory factors dedicated to specific functions.

Ascomycota↗

PubMed2000

A network of proteins around Rvs167p and Rvs161p, two proteins related to the yeast actin cytoskeleton.

The Rvs161p and Rvs167p proteins of Saccharomyces cerevisiae, homologues of higher eukaryotes' amphiphysins, associate with actin and appear to be involved in several functions related to the actin cytoskeleton. In order to identify partners of the Rvsp proteins, yeast libraries constructed in two-hybrid vectors were screened using either Rvs167p or Rvs161p as a bait. The selected candidates, representing 34 ORFs, were then tested against both Rvsp proteins, as well as domains of Rvs167p or Rvs161p. Among the most significant ones, 24 ORFs were specific preys of Rvs167p only and two gave interactions with Rvs161p only. Interestingly, five ORFs were preys of both Rvs161p and Rvs167p (RVS167, LAS17, YNL094w, YMR192w and YPL249c). Analysis of putative functions of the candidates confirm involvement of the Rvsp in endocytosis/vesicle traffic, but also opens possible new fields, such as nuclear functions.

Actins↗

PubMed1997

Inflammatory rheumatism and nasal polyposis.

We report five cases of seronegative inflammatory rheumatism associated with nasal polyposis. The patients were four women and one man, mean age 49.5 years (range 42-59 yrs.). Two patients had polyarthralgia predominating in the hands, wrists and knees and two patients had symmetrical acromelic polyarthritis. The fifth patient, a woman, had oligoarticular arthritis. In a single female patient, X-rays showed moderate erosions of both tarsometatarsal bones. The inflammatory syndrome was moderate with mean ESR 23 (12-38) and immunological investigations were negative except for the presence of pANCA (50-200 U) in three patients. HLA-A1, B8, and Bw35 antigens were found in three of the five patients. In all cases, nasal and sinus polyposis (NSP) preceded rheumatism and the joint symptoms were accompanied by worsening of the ENT symptoms. NSP was confirmed by CT scan of the nasal fossae and sinuses. Polyps were surgically removed in four patients and the histology showed neither granuloma nor vasculitis. In four patients the joint symptoms, which responded poorly to nonsteroidal anti-inflammatory drugs (NSAIDs), improved markedly after ENT treatment (surgery and topical steroids) and synthetic antimalarials. The concomitant course of the joint and ENT symptoms suggests there may be a link between inflammatory rheumatism and NSP.

Adult↗

PubMed1997

Plasma vitellogenin levels during the annual reproductive cycle of the female rainbow trout (Oncorhynchus mykiss): establishment and validation of an ELISA.

Rainbow trout, Oncorhynchus mykiss, vitellogenin (Vtg) was purified from plasma of E2-treated male by direct anion exchange chromatography and some of its biochemical characteristics were studied. Our results demonstrated that, under SDS-PAGE conditions, rainbow trout Vtg was composed of two molecular forms of 390 and 176 kDa representing, respectively, the dimeric form and the monomeric from of the molecule. The purified Vtg was used to raise a polyclonal antibody for Vtg (anti-Vtg). Using this anti-Vtg, a competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of rainbow trout Vtg. The practical sensitivity range of this ELISA was 20-320 ng/ml (80-20% of binding) and the detection limit was 9 ng/ml. The intra- and the inter-assay coefficients of variation (at 50% of binding) were estimated at 1.8% (n = 10) and 3.9% (n = 13), respectively. This ELISA was validated by detecting changes in Vtg levels in rainbow trout at different physiological stages, as well as in 2-year-old female rainbow trout throughout the reproductive cycle.

Animals↗

PubMed1997

No link between avascular necrosis of the femoral head and antiphospholipid antibodies.

The rate of occurrence of antiphospholipid antibodies was compared in 47 patients with avascular necrosis of the femoral head and in 47 controls matched on age and sex. Antiphospholipid antibodies were looked for using three techniques in each patient, namely the VDRL test, an ELISA for anticardiolipin, and a circulating anticoagulant detection procedure involving three different tests. The VDRL and the tests for circulating anticoagulants were negative in all the patients and controls. No significant between-group difference was found for the ELISA, which was positive in three patients and two controls.

Adult↗