| Autor: |
Wolański M; Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, 50-383, Wrocław, Poland. marcin.wolanski@uni.wroc.pl., Łebkowski T; Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, 50-383, Wrocław, Poland., Kois-Ostrowska A; Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, 50-383, Wrocław, Poland., Zettler J; Pharmazeutische Biologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.; German Centre for Infection Research (DZIF), Partner Site, Tübingen, Germany., Apel AK; Pharmazeutische Biologie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.; German Centre for Infection Research (DZIF), Partner Site, Tübingen, Germany., Jakimowicz D; Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, 50-383, Wrocław, Poland.; Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. Weigla 12, 53-114, Wrocław, Poland., Zakrzewska-Czerwińska J; Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14A, 50-383, Wrocław, Poland.; Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, ul. Weigla 12, 53-114, Wrocław, Poland. |
| Abstrakt: |
Aminocoumarins are potent antibiotics belonging to a relatively small group of secondary metabolites produced by actinomycetes. Genome mining of Catenulispora acidiphila has recently led to the discovery of a gene cluster responsible for biosynthesis of novel aminocoumarins, cacibiocins. However, regulation of the expression of this novel gene cluster has not yet been analyzed. In this study, we identify transcriptional regulators of the cacibiocin gene cluster. Using a heterologous expression system, we show that the CabA and CabR proteins encoded by cabA and cabR genes in the cacibiocin gene cluster control the expression of genes involved in the biosynthesis, modification, regulation, and potentially, efflux/resistance of cacibiocins. CabA positively regulates the expression of cabH (the first gene in the cabHIYJKL operon) and cabhal genes encoding key enzymes responsible for the biosynthesis and halogenation of the aminocoumarin moiety, respectively. We provide evidence that CabA is a direct inducer of cacibiocin production, whereas the second transcriptional factor, CabR, is involved in the negative regulation of its own gene and cabT-the latter of which encodes a putative cacibiocin transporter. We also demonstrate that CabR activity is negatively regulated in vitro by aminocoumarin compounds, suggesting the existence of analogous regulation in vivo. Finally, we propose a model of multilevel regulation of gene transcription in the cacibiocin gene cluster by CabA and CabR. |
