A novel TetR-like transcriptional regulator is induced in acid-nitrosative stress and controls expression of an efflux pump in mycobacteria

Perrone, Filomena, De Siena, Barbara, Muscariello, Lidia, Kendall, Sharon L, Waddell, Simon J and Sacco, Margherita (2017) A novel TetR-like transcriptional regulator is induced in acid-nitrosative stress and controls expression of an efflux pump in mycobacteria. Frontiers in Microbiology, 8 (2039). ISSN 1664-302X

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Abstract

Mycobacterium tuberculosis has the ability to survive inside macrophages under acid-nitrosative stress. M. tuberculosis Rv1685c and its ortholog in M. smegmatis, MSMEG_3765, are induced on exposure to acid-nitrosative stress. Both genes are annotated as TetR transcriptional regulators, a family of proteins that regulate a wide range of cellular activities, including multidrug resistance, carbon catabolism and virulence. Here, we demonstrate that MSMEG_3765 is co-transcribed with the upstream genes MSMEG_3762 and MSMEG_3763, encoding efflux pump components. RTq-PCR and GFP-reporter assays showed that the MSMEG_3762/63/65 gene cluster, and the orthologous region in M. tuberculosis (Rv1687c/86c/85c), was up-regulated in a MSMEG_3765 null mutant, suggesting that MSMEG_3765 acts as a repressor, typical of this family of regulators. We further defined the MSMEG_3765 regulon using genome-wide transcriptional profiling and used reporter assays to confirm that the MSMEG_3762/63/65 promoter was induced under acid-nitrosative stress. A putative 36 bp regulatory motif was identified upstream of the gene clusters in both M. smegmatis and M. tuberculosis and purified recombinant MSMEG_3765 protein was found to bind to DNA fragments containing this motif from both M. smegmatis and M. tuberculosis upstream regulatory regions. These results suggest that the TetR repressor MSMEG_3765/Rv1685c controls expression of an efflux pump with an, as yet, undefined role in the mycobacterial response to acid-nitrosative stress.

Item Type: Article
Keywords: health; infection; tuberculosis; mycobacterium; antimicrobial drug resistance
Schools and Departments: Brighton and Sussex Medical School > Brighton and Sussex Medical School
Research Centres and Groups: Wellcome Trust Brighton and Sussex Centre for Global Health Research
Subjects: Q Science
Q Science > QR Microbiology
Q Science > QR Microbiology > QR0075 Bacteria
Depositing User: Simon Waddell
Date Deposited: 02 Nov 2017 15:47
Last Modified: 02 Nov 2017 15:47
URI: http://sro.sussex.ac.uk/id/eprint/70875

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