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Biomedical subjects

D Hulanicka

Publications and source records attributed to D Hulanicka.

At least 19 recordsLinked to original sources
PubMed1998

Integration host factor positively regulates cycJIH transcription.

We report the identification of integration host factor (IHF) as an additional element involved in the regulation of the cysJIH promoter of Salmonella typhimurium and Escherichia coli. An IHF-binding site was located in the regulatory region of the cysJIH promoter by using two methods, protection against DNase I digestion and hydroxyl radical cleavage. The positive influence of IHF on in vitro run-off transcription from the cysJIH promoter is shown. The in vivo observations suggest that IHF is necessary for full expression of cysJIH in stationary phase but not during exponential growth.

Bacterial Proteins↗
PubMed1998

Infectious transcripts from cloned cDNA of potato leafroll luteovirus.

Infectious transcripts play a key role in the research on plant viruses at the molecular level. A number of cDNA clones covering the whole genome of the Polish isolate of potato leafroll virus were constructed. Four overlapping clones were selected and assembled using restriction sites. The full copy was positioned between T7 RNA polymerase promoter and unique ScaI site. The full-length capped transcripts of the sequence of the viral genome synthesised in vitro were able to replicate in protoplasts and to produce the viral coat protein.

DNA, Complementary↗
PubMed1995

Sulfate and thiosulfate transport in Escherichia coli K-12: evidence for a functional overlapping of sulfate- and thiosulfate-binding proteins.

In Escherichia coli, sulfate and thiosulfate ions are transported by an ABC-type transporter consisting of both the membrane components (the products of cysT, cysW, and cysA genes) and the periplasmic binders (the products of cysP and sbp genes). The single cysP and sbp mutants are able to utilize both sulfate and thiosulfate as a sole sulfur source, while the inactivation of both genes leads to cysteine auxotrophy resulting from the block in the transport of both ions.

Amino Acid Sequence↗
PubMed1993

Structural requirements for efficient translational frameshifting in the synthesis of the putative viral RNA-dependent RNA polymerase of potato leafroll virus.

The putative RNA-dependent RNA polymerase of potato leafroll luteovirus (PLRV) is expressed by -1 ribosomal frameshifting in the region where the open reading frames (ORF) of proteins 2a and 2b overlap. The signal responsible for efficient frameshift is composed of the slippery site UUUAAAU followed by a sequence that has the potential to adopt two alternative folding patterns, either a structure involving a pseudoknot, or a simple stem-loop structure. To investigate the structure requirements for efficient frameshifting, mutants in the stem-loop or in the potential pseudoknot regions of a Polish isolate of PLRV (PLRV-P) have been analyzed. Mutations that are located in the second stem (S2) of the potential pseudoknot structure, but are located in unpaired regions of the alternative stem-loop structure, reduce frameshift efficiency. Deletion of the 3' end sequence of the alternative stem-loop structure does not reduce frameshift efficiency. Our results confirm that -1 frameshift in the overlap region depends on the slippery site and on the downstream positioned sequence, and propose that in PLRV-P a pseudoknot is required for efficient frameshifting. These results are in agreement with those recently published for the closely related beet western yellows luteovirus (BWYV).

Base Sequence↗
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↗