PubMed Health⌕ Search

Biomedical subjects

S Véronneau

Publications and source records attributed to S Véronneau.

7 recordsLinked to original sources
PubMed1999

Functional characterization of the S. cerevisiae genome by gene deletion and parallel analysis.

The functions of many open reading frames (ORFs) identified in genome-sequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.

Culture Media↗
PubMed1999

Mnt2p and Mnt3p of Saccharomyces cerevisiae are members of the Mnn1p family of alpha-1,3-mannosyltransferases responsible for adding the terminal mannose residues of O-linked oligosaccharides.

The genome of Saccharomyces cerevisiae contains five genes that encode type II transmembrane proteins with significant amino acid similarity to the alpha-1,3-mannosyltransferase Mnn1p. The roles of the three genes most closely related to MNN1 were examined in mutants carrying single and multiple combinations of the disrupted genes. Paper chromatographic analysis of [2-3H]mannose-labeled O-linked oligosaccharides released by beta-elimination showed that the MNT2 (YGL257c) and MNT3 (YIL014w) genes in combination with MNN1 have overlapping roles in the addition of the fourth and fifth alpha-1,3-linked mannose residues to form Man4 and Man5 oligosaccharides whereas MNT4 (YNR059w) does not appear to be required for O-glycan synthesis.

Amino Acid Sequence↗
PubMed1997

Ontogeny of epidermal growth factor (EGF), EGF receptor (EGFR) and basic fibroblast growth factor (bFGF) mRNA levels in pancreas, liver, kidney, and skeletal muscle of pig.

Epidermal growth factor (EGF), EGF receptor (EGFR), and basic fibroblast growth factor (bFGF) messenger RNA (mRNA) levels were examined by Northern blot analysis in four tissues (pancreas, liver, kidney, and skeletal muscle) of pig from fetal 90 d to postnatal 180 d of age. The present study shows for the first time that EGF mRNA increased with advancing age in the kidney and skeletal muscle of pig. A high level of EGF mRNA was observed in the kidney compared with the liver and skeletal muscle. In the pancreas, high levels of EGF mRNA were found in fetuses and newborns and were low in older pigs. Pancreatic EGFR mRNA level parallelled its EGF mRNA, whereas in the kidney and skeletal muscle, patterns of EGFR mRNA were reversed to their EGF mRNA levels. In the liver, EGFR mRNA was abundant but EGF mRNA was undetected. In the pancreas and skeletal muscle, the highest levels of bFGF mRNA were found in fetuses of 90 d of age and then decreased with advancing age. In the liver and kidney, there were no major changes in bFGF mRNA levels during the examined developmental periods. These results show that EGF, EGFR, and bFGF mRNA levels are developmentally and tissue specifically regulated in pig. In the pancreas, mRNA levels of EGF, EGFR and bFGF were high in fetal and neonatal life and low thereafter. In the kidney and skeletal muscle, EGF mRNA increased with advancing age. EGF may play a role in muscle growth and maintenance in growing pigs during the later stage of development.

Aging↗
PubMed1996

The hamster adrenal cytochrome P450C11 has equipotent 11beta-hydroxylase and 19-hydroxylase activities, but no aldosterone synthase activity.

We have isolated a hamster adrenal P45OC11 cDNA which shared 90 and 84% homology, respectively, with the nucleotide sequence and the amino acid sequence of the hamster adrenal P450aldo. Both P450C11 and P450aldo cDNA coding sequences were inserted in the plasmid pBluescript SK, transcribed and then translated using a rabbit reticulocyte system in the presence of [35S]methionine. The reaction products were immunoprecipitated with an anti-bovine P450C11 antibody for P450C11 and with an anti-hamster P450aldo for P450aldo. Immunoprecipitated proteins were analyzed by polyacrylamide gel electrophoresis. A single 35S-labeled protein band was detected for P450C11 and for P450aldo, respectively. P450C11 and P450aldo cDNAs were then both inserted into the expression vector pCMV5 containing a viral sequence specific for the attachment of ribosomes to mRNA. These constructions were transfected in COS-1 cells. 24 h after transfection, the presence of P450C11 and P450aldo mRNAs was determined by Northern blot analysis. In a time study experiment we found that P450C11 transformed the labeled-steroid into [14C]corticosterone, [14C]19-OH-deoxycorticosterone and [14C]18-OH-deoxycorticosterone in ratios of 1:1.11:0.07, after 2 h of incubation; no [14C]aldosterone could be detected. Cells transfected with plasmids harboring the P450aldo cDNA transformed [14C]deoxycorticosterone to [14C]corticosterone, [14C]aldosterone, [14C]18-OH-corticosterone, [14C]18-OH-deoxycorticosterone, [14C]19-OH-deoxycorticosterone and [14C]11-dehydrocorticosterone in ratios of 1:0.25:0.45:0.04:0.04:0.04 after 12 h of incubation. These results indicate that one P450 catalyzes the ultimate step of glucocorticoid formation and a separate P450 is involved in the final steps of aldosterone formation in hamster adrenals. The capacity of the hamster adrenal P450C11 to hydroxylate at positions 11beta and 19 in nearly equal ratio makes this animal an excellent model to study the mechanism of synthesis and inhibition of 19-OH-deoxycorticosterone, the precursor of 19-nor-deoxycorticosterone, a very potent mineralocorticoid involved in the development of essential hypertension.

Adrenal Glands↗
PubMed1994

The presence of two cytochrome P450 aldosterone synthase mRNAs in the hamster adrenal.

We isolated a cDNA from a hamster adrenal cDNA library which was similar in sequence to those of the mouse and rat P450c18 cDNAs. The hamster P450c18 cDNA, however, was shorter than the rat and mouse P450c18 cDNAs at its 5'-end and the peptide leader sequence was absent. From a hamster genomic library we isolated and sequenced the first seven exons and a 5'-flanking region of the first P450c18 gene exon. With this information we were able to generate a P450c18 cDNA containing the peptide leader sequence using the polymerase chain reaction. Northern analyses were performed on adrenals from hamsters maintained on a low sodium diet for 0, 4, 7 and 10 days using a 32P-labeled sequence specific to P450c18; two mRNA bands were found at 2 and 3.4 kb. The intensity of both bands was increased about 3- to 5-fold under sodium restriction compared to controls. A distinct mRNA band of 2.3 kb hybridized with an oligonucleotide specific to P450(11) beta and its intensity did not change following low sodium intake. Immunoblotting analyses were performed using an antibovine adrenal P450(11) beta antibody that does not discriminate between P450(11) beta and P450c18 proteins. Three bands were detected at 52, 48 and 45 kDa in homogenate preparations of entire glands. Furthermore, the 45 kDa protein band was present in homogenates of the zona glomerulosa and absent in homogenates of the zone fasciculata-reticularis. In conclusion, these results show that the hamster adrenals express P450c18 as do mouse, rat and human adrenal glands. Furthermore, two P450c18 mRNAs, which are inducible by a low sodium intake, are present in the hamster adrenal vs one for the rat. The physiological role of these two hamster adrenal mRNA species remains to be elucidated.

Adrenal Glands↗
PubMedDate not supplied

Ontogeny of IGFs and IGFBPs mRNA levels and tissue concentrations in liver, kidney and skeletal muscle of pig.

As far as we know, there is no available information about ontogenic changes of tissue concentrations of IGF-I and II and IGFBPs in large mammals. Serum, liver and kidney levels of IGFs and IGFBPs were examined in fetuses at 90 and 110 days of gestation and in pigs at 1d, 3 wk, 3 mo and 6 mo of age. Ontogeny of mRNA levels of IGFs, IGF type I and type II receptors (IGFI-R and IGFII-R), IGFBP-1 and -3 (IGFBPs) and growth hormone receptor (GHR) were also examined by Northern blot analysis in liver, kidney and skeletal muscle of pig. Serum IGF-I, IGF-II and IGFBP-3 concentrations were low during the fetal life and increased after birth. The highest level of IGF-II mRNA was found in fetuses for all studied tissues. In the liver, IGF-I mRNA level and its protein content peaked at 3 wk of age. The highest IGF-II concentration was found at 1d and 3 wk of age. The IGFII-R mRNA remained at a constant level during the whole development period. The most abundant IGFBP-1 mRNA and its protein content were found at birth. The level of IGFBP-2 was high during fetal and early postnatal life. The IGFBP-3 content was relatively low in fetuses and reached the highest level after 3 wk of age. In the kidney, IGFs, IGFBP-3, IGFI-R and IGFII-R as well as GHR mRNA levels were relatively high during the fetal and early postnatal life. The IGFs concentrations were the highest in newborns. In the skeletal muscle, IGFs, IGFBP-3 and IGFI-R mRNA levels decreased with advancing age. During the postnatal life, the high IGFs concentrations in the liver and the kidney correspond to fast growth periods of these organs.

Animals↗