Rückert, Christian and Milse, Johanna and Albersmeier, Andreas and Koch, Daniel J. and Pühler, Alfred and Kalinowski, Jörn (2008) The dual transcriptional regulator CysR in Corynebacterium glutamicum ATCC 13032 controls a subset of genes of the McbR regulon in response to the availability of sulphide acceptor molecules. BMC Genomics, 9 (483). ISSN 1471-2164 http://resolver.caltech.edu/CaltechAUTHORS:RUCbmcg08
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Background: Regulation of sulphur metabolism in Corynebacterium glutamicum ATCC 13032 has been studied intensively in the last few years, due to its industrial as well as scientific importance. Previously, the gene cg0156 was shown to belong to the regulon of McbR, a global transcriptional repressor of sulphur metabolism in C. glutamicum. This gene encodes a putative ROK-type regulator, a paralogue of the activator of sulphonate utilisation, SsuR. Therefore, it is an interesting candidate for study to further the understanding of the regulation of sulphur metabolism in C. glutamicum. Results: Deletion of cg0156, now designated cysR, results in the inability of the mutant to utilise sulphate and aliphatic sulphonates. DNA microarray hybridisations revealed 49 genes with significantly increased and 48 with decreased transcript levels in presence of the native CysR compared to a cysR deletion mutant. Among the genes positively controlled by CysR were the gene cluster involved in sulphate reduction, fpr2 cysIXHDNYZ, and ssuR. Gel retardation experiments demonstrated that binding of CysR to DNA depends in vitro on the presence of either O-acetyl-L-serine or O-acetyl-L-homoserine. Mapping of the transcription start points of five transcription units helped to identify a 10 bp inverted repeat as the possible CysR binding site. Subsequent in vivo tests proved this motif to be necessary for CysR-dependent transcriptional regulation. Conclusion: CysR acts as the functional analogue of the unrelated LysR-type regulator CysB from Escherichia coli, controlling sulphide production in response to acceptor availability. In both bacteria, gene duplication events seem to have taken place which resulted in the evolution of dedicated regulators for the control of sulphonate utilisation. The striking convergent evolution of network topology indicates the strong selective pressure to control the metabolism of the essential but often toxic sulphur-containing (bio-)molecules.
|Additional Information:||© 2008 Rückert et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received: 10 July 2008. Accepted: 14 October 2008. Published: 14 October 2008. We thank Carola Eck for assistance during MALDI-TOF mass spectrometry. CR and DJK acknowledge the receipt of a grant from the International NRW Graduate School in Bioinformatics and Genome Research. The work was supported by the Bundesministerium für Bildung und Forschung (grant 0313805A) and in part by Evonik Degussa GmbH (Düsseldorf, Germany). Authors' contributions: CR wrote the manuscript, performed the bioinformatic analyses and carried out the mutational and transcriptional studies. JM aided the transcriptional studies, purified CysR and performed the electrophoretic mobility shift assays. DJK aided the mutational analysis and performed the growth tests. AA performed the mapping of transcriptional start points. AP aided in coordination and conceived of the design of tables and figures. JK conceived and coordinated this study. All authors read and approved of the final manuscript.|
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|Deposited On:||11 Nov 2008 18:48|
|Last Modified:||26 Dec 2012 10:30|
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