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D Hulanicka

Publications and source records attributed to D Hulanicka.

At least 19 recordsLinked to original sources
PubMed1990

Sulfate and thiosulfate transport in Escherichia coli K-12: nucleotide sequence and expression of the cysTWAM gene cluster.

The nucleotide sequence of the sulfate and thiosulfate transport gene cluster has been determined and located 3' to the gene (cysP) encoding the thiosulfate-binding protein. Four open reading frames, designated cysT, cysW, cysA, and cysM, have been identified. Similarities in primary structure were observed between (i) the deduced amino acid sequences of CysT and CysW with membrane-bound components of other binding protein-dependent transport systems, (ii) that of the CysA sequence with the "conserved" component of such systems, and (iii) that of the CysM sequence with O-acetylserine sulfhydrylase A (cysK gene product) and the beta-subunit of tryptophan synthase (coded by trpB). Expression of the four genes was analyzed in the T7 promoter-polymerase system.

Amino Acid Sequence↗
PubMed1990

Sulfate and thiosulfate transport in Escherichia coli K-12: identification of a gene encoding a novel protein involved in thiosulfate binding.

The sequence of 1,973 nucleotides encompassing the region at and directly adjacent to the CysB-dependent promoter controlling expression and synthesis of the sulfate-thiosulfate transport system of Escherichia coli has been determined. The transcription start site has been mapped by primer extension. One open reading frame representing the first gene of the presumed sulfate transport operon was identified and designated cysP. The deduced amino acid sequence of the CysP polypeptide indicates the presence of a signal peptide. Expression of the cysP gene in the T7 promoter-polymerase system revealed the location of the gene product in the periplasm. Construction of a cysP insertional mutant and assays of binding and uptake of sulfate and thiosulfate by this mutant allowed the identification of the cysP gene product as a thiosulfate-binding protein. The TGA termination codon of cysP was found to overlap the putative ATG initiation codon of the next open reading frame, inferred as being essential for the sulfate transport system, and it was designated cysT. Preliminary sequence data from the corresponding region of the Salmonella typhimurium chromosome showed strictly homologous counterparts of the E. coli cysP and cysT genes.

Amino Acid Sequence↗
PubMed1989

Identification and mapping of the sulphate permease promoter region in Escherichia coli.

The cys329::lac fusion linking the lacZ gene to the regulatory region of cys locus involved in sulphate transport in E. coli, was cloned and localized within the restriction map of cysA region. The region containing the cysB-dependent promoter governing the expression of sulphate transport system was identified and the direction of transcription from this promoter has been established. Two complementation groups specified by different mutations in cysA region of E. coli were found.

Escherichia coli↗
PubMed1987

Cloning of cysB mutant alleles of S. typhimurium.

Two cysB mutant alleles of S. typhimurium have been cloned onto pBR vectors. The product of the constitutive cysBc 1352 allele present on the plasmid was found to fulfill regulatory functions: as an activator of the cysteine regulon and as an autorepressor. CysB70 auxotrophic mutation impairs both regulatory functions cysB protein. Transfer of the clones cysBc 1352 allele from E. coli to S. typhimurium and from S. typhimurium to E. coli and biochemical analysis of transformants suggest involvement of a restriction-modification system in the constitutive expression of the cysteine regulon.

Alleles↗
PubMed1986

Effect of DNA gyrase inhibitors and urea on the expression of cysB, the regulatory gene of the cysteine regulon.

cysB, the regulatory gene of the cysteine regulon, is autoregulated. Inhibitors of both gyrase subunits, nalidixic acid and novobiocin, affect the expression of cysB, as monitored by beta-galactosidase activity in cysB::lac fusion strains. In gyrA mutants that are resistant to nalidixic acid, this drug does not affect cysB expression. The amount of mRNA transcribed from the cysB promoter isolated from cultures grown in the presence of gyrase inhibitors was significantly lower than that from the control culture without inhibitors. Urea also decreased cysB expression. These results suggest that DNA topology could play a role in cysB expression.

Cysteine↗
PubMed1986

Regulation of the cysB gene expression in Escherichia coli.

It was found by Northern-type hybridization that the amount of RNA, the transcription of which begins at the cysB regulatory gene promoter, is significantly reduced after cysB gene introduction into Escherichia coli on multicopy plasmid. This result indicates that cysB protein inhibits the transcription of its own gene. O-acetyl-L-serine, an internal inducer of E. coli and Salmonella typhimurin cysteine regulons, has no effect on cysB gene expression.

Escherichia coli↗
PubMed1982

A new class of mutants of the cysB regulatory gene for cysteine biosynthesis in Salmonella typhimurium.

A new class of regulatory mutants in the cysB locus has been isolated by plating cysM strains, under anaerobic conditions, on medium containing 1,2,4-triazole. The isolated cysB mutants are cysteine prototrophs and triazole-resistant, although the levels of cysteine and O-acetyl-L-serine sulphydrylase are not changed. In contrast to the constitutive cysB mutants identified previously, the expression of the cysteine biosynthetic enzymes in the newly isolated mutants is regulated by the same factors as in wild-type strains. In the double mutant cysE cysB2971, the cysteine biosynthetic enzymes are absent with the exception of O-acetyl-L-serine sulphydrylase.

Chromosome Mapping↗
PubMed1982

Delayed inducibility of sulphite reductase in cysM mutants of Salmonella typhimurium under anaerobic conditions.

Salmonella typhimurium cysM mutants grow at a normal rate under aerobic conditions, but only after a lag period under anaerobic conditions. No difference in the induction of two cysteine biosynthetic enzymes--sulphite reductase and O-acetyl-L-serine sulphydrylase--in wild-type, cysK and cysM strains was observed under aerobic conditions. Under anaerobic conditions, however, the cysM strain differed from the others in showing a long delay in the induction of sulphite reductase. These observations are consistent with the assumption that the observed growth delay of the cysM mutant under anaerobic conditions is the result of abnormalities in the regulation of sulphite reductase.

Anaerobiosis↗
PubMed1981

Effect of DNA gyrase inhibitors on gene expression of the cysteine regulon.

Nalidixic acid inhibits the expression of those cysteine genes which are regulated by the cysB product, it has no affect, however, on the constitutively-expressed cysE gene. The expression of cysteine genes in a strain carrying a mutation in the nalA locus is resistant to this drug. Novobiocin affects the expression of cysteine genes similarly to nalidixic acid. The effect of nalidixic acid on the expression of genes in a cysteine constitutive mutant was studied.

Acetyltransferases↗
PubMed1981

Use of gene fusions to study expression of cysB, the regulatory gene of the cysteine regulon.

Strains of escherichia coli were constructed in which the lacZ gene is fused to cysB, the positive regulator gene of the cysteine regulon. The fusion strains were used to study the regulation of the cysB gene by assaying the fused lacZ gene product. The introduction of a cysB allele, either on a plasmid or on an episome to the fusion strains, resulted in the decrease of beta-galactosidase activity. This implies that the cysB gene expression is autoregulated by its own product. The direction of cysB gene transcription was determined to be clockwise.

Cysteine↗
PubMed1979

Constitutive mutation of cysJIH operon in a cysB deletion strain of Salmonella typhimurium.

In a cysB deletion strain a new mutation, denoted cys-2332 was isolated, which causes the constitutive expression of the cysJIH operon. cys-2332 is closely linked to cysJIH and presumably is located in the initiator region of this operon, rendering its expression independent of the cysB gene product and the internal inducer O-acetyl-L-serine. The presence of sulfite reductase (encoded by cysI and cysJ) activity in a cysB- cys-2332 double mutant indicates that cysG, which is not linked to cysJIH but is required for the synthesis of the sulfite reductase co-factor siroheme, is not controlled by cysB.

Chromosome Mapping↗
PubMed1979

Properties of cysK mutants of Escherichia coli K12.

Triazole and azaserine resistant mutants of E. coli K12 affecting cysK gene coding for O-acetylserine sulphydrylase were isolated. The cysK gene in E. coli is located in the same region of chromosome as the cycK gene in Salmonella typhimurium. All azaserine and some triazole resistant mutants require cysteine for growth at a normal rate. The cysK mutants have reduced sulphate uptake. Stability and transfer by conjugation of triazole resistant phenotype were checked. Differences in sulphate metabolism between closely related organisms E. coli and S. typhimurium are discussed.

Azaserine↗
PubMed1978

Method of isolation of cysteine constitutive mutants of the cysteine regulon in Salmonella typhimurium.

A method for selection of constitutive cysB mutation is described which takes advantage of the resistance of cysteine constitutive mutants to 1,2,4-triazole. Since cysM cysK double mutants are cysteine auxotrophs, by selecting for triazole resistance in cysM strains, mutants arising under this condition also should be constitutive for cysteine biosynthesis. Genetic analysis of mutants isolated by this technique showed that their mutational sites are located in the cysB region. Biochemical assays of cysteine enzymes, sulphite reductase and O-acetylserine sulfhydrylase of the mutants showed the derepressed level of these enzymes and the lack or slight repression by 1-cysteine.

Cysteine↗