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J Bouvier

Publications and source records attributed to J Bouvier.

50 records · Page 3Linked to original sources
PubMed1985

Two functional domains conserved in major and alternate bacterial sigma factors.

Sequences of the sigma factors of Escherichia coli and Bacillus subtilis were aligned with the sequences of two sigma-like proteins, HtpR, involved in the expression of heat-shock genes in E. coli, and SpoIIG, necessary for endospore formation in B. subtilis. An internal region is highly conserved in the four proteins and is proposed to be involved in binding of sigma factors to core RNA polymerase. The carboxy-terminal part of the four proteins presents the characteristic structure found in several prokaryotic DNA-binding proteins and is proposed to be involved in promoter recognition.

Amino Acid Sequence↗
PubMed1985

Expression in mammalian cells of the diaminopimelic acid decarboxylase of Escherichia coli permits cell growth in lysine-free medium.

The lysA gene of Escherichia coli encodes for a diaminopimelic acid decarboxylase (EC 4.1.1.20) which allows the conversion of diaminopimelic acid into lysine in bacteria. It has been cloned in an eukaryotic expression vector containing upstream the SV40 early promoting sequence, and downstream mouse alpha-globin maturating sequences. The recombinant plasmid pSB99 (4800 base pairs) has been introduced into several mammalian cell lines by cotransfection with a second selectable marker i.e. the polyoma-transforming DNA. Selection for morphologically transformed rat cells which contained the intact lysA sequences, allowed the determination of the concentration of diaminopimelic acid in the lysine-free medium that permitted cell growth. lysA-expressing clones were directly selected in a medium containing 10 mM diaminopimelic acid, after transfection with pSB99 alone. Southern blot analysis on selected clones have shown that they contain up to 30-50 integrated copies of the plasmid in tandem arrangement. Finally, we demonstrated that lysA-expressing clones incorporate a significant amount of radiolabelled [3H]diaminopimelic acid in acid-insoluble material. The recombinant plasmid can serve as a selectable marker, in growth medium in which lysine was replaced by its direct bacterial precursor.

Animals↗
PubMed1985

Evidence that the major surface proteins of three Leishmania species are structurally related.

Promastigotes of Leishmania major LRC-L137, L. donovani LEM 75, and L. tropica LRC-L32 were surface radioiodinated. The proteins of the parasites were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and labeled molecules were revealed by fluorography. A single major iodinated protein of Mr 63 000 (p63) was identified in each of the three species. These proteins were partially purified by phase separation in Triton X-114 solution, demonstrating that the p63 of each of the three species is the most abundant integral membrane protein in the promastigote. Peptide maps were obtained by partial proteolysis with N-chlorosuccinimide or Staphylococcus V8 protease followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The maps of L. major and L. donovani were identical, but only partially homologous to the maps of L. tropica p63. Finally, immunological crossreactivity among the three p63s was demonstrated with the serum of a mouse immunized with purified L. major p63, and the serum of a dog naturally infected with L. donovani. The data show that the major surface proteins found on promastigotes of three Old World Leishmania species are structurally related.

Animals↗
PubMed1984

Nucleotide sequence and expression of the Escherichia coli dapB gene.

The Escherichia coli dapB gene encodes dihydrodipicolinate reductase. This enzyme is part of the diaminopimelate-lysine pathway, and its synthesis is repressed by lysine. The dapB gene was cloned into pBR322 from a transducing lambda bacteriophage, its complete nucleotide sequence established, and the transcriptional start localized. The DNA sequence predicts that the dapB gene codes for a 273-amino acid polypeptide, Mr 28,798. No attenuation-type sequence can be found between the mRNA start and the coding sequence. The dapB promoter signals appear to be weak as compared to RNA polymerase consensus sequences. Nevertheless an efficient in vivo synthesis of beta-galactosidase was obtained when the lac operon was inserted in vitro in the dapB gene, downstream of the dapB regulatory signals. Further studies were performed on an in-frame gene fusion constructed in vitro between the dapB and the lacZ genes. They indicated that repression by lysine is exerted on a DNA region restricted to a 153-base pair fragment with only 102 nontranscribed nucleotides. Finally, dapB gene expression showed a gene dosage effect which suggests that it is not controlled by an element present in limiting amounts in the cell.

Amino Acid Sequence↗
PubMed1984

Multiple regulatory signals in the control region of the Escherichia coli carAB operon.

The first reaction in pyrimidine and arginine biosynthesis in Escherichia coli is catalyzed by a single enzyme, carbamoyl-phosphate synthetase (EC 6.3.5.5), the product of the carAB operon. Expression of this operon is cumulatively repressed by arginine and pyrimidines. The nucleotide sequence of the carAB control region was determined and transcriptional starts were localized. Two adjacent promoters, 70 base pairs apart, appear to be used in vivo, the downstream one overlapping a typical arginine operator. The absence of any attenuation-like sequence excludes such a mechanism for pyrimidine-mediated repression. Various fragments of the carA promoter-proximal region were fused in vitro with the lacZ gene. Results obtained with these fusions indicate that (i) translation of the carA gene can be initiated in vivo without an AUG codon but very likely with an UUG or an AUU codon; (ii) the carAB downstream promoter is repressed by arginine; and (iii) the carAB upstream promoter is repressed by pyrimidines and subject to stringent control. When carried by a multicopy plasmid the carAB control region escapes repression by arginine and pyrimidines. The existence of a pyrimidine repressor, present in limiting amounts in the cell, is therefore postulated.

Amino Acid Sequence↗
PubMed1984

Nucleotide sequence of the spo0B gene of Bacillus subtilis and regulation of its expression.

The spo0B gene is one of the genes involved in initiation of sporulation of Bacillus subtilis. This gene, previously cloned into the pHV33 shuttle vector, is expressed in Escherichia coli and B. subtilis. We have determined the sequence of 1118 base pairs (bp) of the DNA insert carrying the spo0B gene. The promoter sequence of this gene shows the canonical T-A-T-A-A-T region at 10 bp from the transcriptional start (-10 region) but an unusual sequence, T-T-T-T-C-T-, in the -35 region. The nucleotide sequence shows an open reading frame encoding a 192-amino-acid polypeptide of Mr 22,542, which is close to the molecular weight of the spo0B product synthesized in E. coli minicells. To investigate the regulation of the spo0B gene under a variety of physiological conditions, we constructed an in-frame fusion between the spo0B promoter proximal region and the lacZ gene of E. coli. This hybrid gene was subsequently integrated into the B. subtilis chromosome, and the beta-galactosidase activity was measured. It was found that the spo0B gene is preferentially expressed during exponential growth; it is not induced by exhaustion of the growth medium nor repressed by glucose.

Bacillus subtilis↗
PubMed1984

Immunogenic proteins of Leishmania major during mouse infection.

Mice of different strains (C3H/He, A/Jax, DBA/2, BALB/c and CBA/Ca) were infected intracutaneously with Leishmania major. Antibody production was analysed on the antigens of the promastigote form of the parasite which had previously been separated by SDS-polyacrylamide gel electrophoresis and transferred to nitrocellulose sheets. The kinetics of IgG antibody production were determined and the major immunogenic proteins of the parasite were identified for each strain of mouse. It was found that: 1 Antibody directed against parasite proteins appeared in the blood in all mouse strains tested soon after the first week of infection and rose steadily for 5 to 12 weeks. 2 Qualitative individual variation within a given strain was commonly observed in the response to the various antigens. Each mouse strain synthesized IgG directed against a somewhat different spectrum of parasite proteins. Homologies in antigen recognition by pooled sera of five mice ranged from 54% to 79% from one mouse strain to another. Hybrid mice from a BALB/c X CBA cross (F1 generation) recognized essentially all antigens recognized by the two parents. Proteins of L. major with apparent molecular weights of 19 kD, 60 kD, 65 kD, 70 kD and greater than 100 kD were immunogenic in all strains of mice tested.

Animals↗
PubMed1982

Membrane potential stimulated binding of the maltose-binding protein to membrane vesicles of Escherichia coli.

We show in this study that radioactively labelled purified maltose-binding protein of Escherichia coli binds specifically to membrane vesicles, in the presence of maltose. When a potential is imposed across the membrane, the specific binding is increased, dependent on maltose, abolished in a mutant defective in the tar-gene product, one of the methyl-accepting chemotaxis proteins.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

A developmental gene product of Bacillus subtilis homologous to the sigma factor of Escherichia coli.

Sporulation of Bacillus subtilis involves sequential morphological and biochemical changes and is regulated by specific genes (spo genes) estimated to occupy more than 30 loci. A mutation in any one of these genes blocks the sporulation process at the corresponding developmental stage. Despite intensive genetic studies, the nature and function of the spo gene products remain unknown. Vegetative B. subtilis RNA polymerase core enzyme may interact with several sigma factors and discriminate among different classes of promoters. During sporulation, new polypeptides are associated with the core enzyme which may have a central role in modifying its promoter recognition specificity. As a first step to understanding their function in the switch from vegetative to sporulation mode, several early sporulation genes have been cloned and analysed. Here we report the cloning and nucleotide sequence of the spoIIG gene of B. subtilis. This gene encodes a polypeptide with a predicted relative molecular mass of 27,652 which contains a 65-amino acid region highly homologous to an internal part of the Escherichia coli sigma factor.

Amino Acid Sequence↗