R Knirschová

Slovak Academy of Sciences, Bratislava, Bratislavsky Kraj, Slovakia

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Publications (5)7.73 Total impact

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    ABSTRACT: We previously identified a polyketide synthase gene cluster, aur1, responsible for the production of the angucycline antibiotic auricin in Streptomyces aureofaciens CCM 3239. A sequence analysis of the aur1 flanking regions revealed the presence of several genes encoding proteins homologous to those for Streptomyces linear plasmid replication, partitioning, and telomere-binding. Pulse-field gel electrophoresis detected the single, 240-kb linear plasmid, pSA3239, in S. aureofaciens CCM3239. The presence of the auricin cluster in pSA3239 was confirmed by several approaches. In addition to aur1, pSA3239 also carries a large number of regulatory genes and two gene clusters involved in production of secondary metabolites: the aur2 cluster for an unknown secondary metabolite and the bpsA cluster for the blue pigment indigoidine. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
    FEMS Microbiology Letters 02/2013; · 2.05 Impact Factor
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    ABSTRACT: A DNA fragment containing part of the salinomycin biosynthetic gene cluster from industrial strain Streptomyces albus CCM 4719 was cloned. Sequence analysis of the 25.809-kbp fragment revealed the presence of 8 open reading frames (ORFs), including two large ORFs encoding three modular sets of oligoketide synthase, followed by three genes (salRI, salRII, salRIII) encoding transcriptional regulators. The first two regulators, SalRI and SalRII, belonged to the novel LAL family of large transcriptional regulators. SalRIII was highly similar to the NysRIV, AmphRIV, and FscRI transcriptional regulators from the oligoene macrolides nystatin, amphotericin, and R008/candicidin clusters, respectively.
    Folia Microbiologica 02/2007; 52(4):359-65. · 0.79 Impact Factor
  • D Homerová, R Knirschová, J Kormanec
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    ABSTRACT: Transcription from the chiC promoter, directing expression of the chitinase gene, chiC, in Streptomyces coelicolor, was analyzed using xylE reporter gene and high-resolution S1-nuclease mapping. The transcription from the chiC promoter was induced by chitin, and this induction was dramatically reduced in the S. coelicolor chiR-disrupted strain. This indicated a dependence of chiC expression upon the chiR gene encoding a response regulator protein. To investigate this relationship, the S. coelicolor ChiR was overproduced using Escherichia coli T7 RNA polymerase expression system. However, gel mobility shift-assay with such a purified ChiR showed no binding in the chiC promoter region, which indicates a lack of specific phosphorylation of E. coli overproduced ChiR that is necessary for DNA-binding activity of response regulators.
    Folia Microbiologica 02/2002; 47(5):499-505. · 0.79 Impact Factor
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    ABSTRACT: We cloned a new gene, sigH, encoding an alternative sigma factor in Streptomyces coelicolor A3(2). The deduced protein of 354 amino acids with an M(r) of 39486 showed greatest similarity to the sporulation sigma factor (sigma(F)) of S. coelicolor, general stress-response sigma(B) of Bacillus subtilis, and stationary-phase stress-response sigma(F) of Mycobacterium tuberculosis. Sequence analysis of the upstream region revealed an ORF encoding a protein (UshX) similar to several anti-sigma factors, and short ORF (UshY) containing zinc-finger DNA binding motif. Transcriptional analysis revealed that all three genes are located on the same polycistronic transcript in order ushY, ushX, and sigH. Expression of the operon was directed by four promoters differentially expressed in the course of differentiation. The first (P1) constitutive promoter was located upstream of ushY. The other three promoters (P2, P3, and P4) were located upstream of ushX, and were differentially induced after various stress conditions. The magnitude of the induction was greatest after osmotic stress and heat shock.
    FEMS Microbiology Letters 09/2000; 189(1):31-8. · 2.05 Impact Factor
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    [Show abstract] [Hide abstract]
    ABSTRACT: We cloned a new gene, sigH, encoding an alternative σ factor in Streptomyces coelicolor A3(2). The deduced protein of 354 amino acids with an Mr of 39 486 showed greatest similarity to the sporulation σ factor (σF) of S. coelicolor, general stress-response σB of Bacillus subtilis, and stationary-phase stress-response σF of Mycobacterium tuberculosis. Sequence analysis of the upstream region revealed an ORF encoding a protein (UshX) similar to several anti-σ factors, and short ORF (UshY) containing zinc-finger DNA binding motif. Transcriptional analysis revealed that all three genes are located on the same polycistronic transcript in order ushY, ushX, and sigH. Expression of the operon was directed by four promoters differentially expressed in the course of differentiation. The first (P1) constitutive promoter was located upstream of ushY. The other three promoters (P2, P3, and P4) were located upstream of ushX, and were differentially induced after various stress conditions. The magnitude of the induction was greatest after osmotic stress and heat shock.
    FEMS Microbiology Letters 08/2000; 189(1). · 2.05 Impact Factor