Mycobacterium tuberculosis Response Regulators, DevR and NarL, Interact in Vivo and Co-regulate Gene Expression during Aerobic Nitrate Metabolism

Malhotra, Vandana and Agrawal, Ruchi and Duncan, Tammi R and Saini, Deepak K and Clark-Curtiss, Josephine E (2015) Mycobacterium tuberculosis Response Regulators, DevR and NarL, Interact in Vivo and Co-regulate Gene Expression during Aerobic Nitrate Metabolism. In: JOURNAL OF BIOLOGICAL CHEMISTRY, 290 (13). pp. 8294-8309.

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Abstract

Mycobacterium tuberculosis genes Rv0844c/Rv0845 encoding the NarL response regulator and NarS histidine kinase are hypothesized to constitute a two-component system involved in the regulation of nitrate metabolism. However, there is no experimental evidence to support this. In this study, we established M. tuberculosis NarL/NarS as a functional two-component system and identified His(241) and Asp(61) as conserved phosphorylation sites in NarS and NarL, respectively. Transcriptional profiling between M. tuberculosis H37Rv and Delta narL mutant strain during exponential growth in broth cultures with or without nitrate defined an similar to 30-gene NarL regulon that exhibited significant overlap with DevR-regulated genes, thereby implicating a role for the DevR response regulator in the regulation of nitrate metabolism. Notably, expression analysis of a subset of genes common to NarL and DevR regulons in M. tuberculosis Delta devR, Delta devS Delta dosT, and Delta narL mutant strains revealed that in response to nitrite produced during aerobic nitrate metabolism, the DevRS/DosT regulatory system plays a primary role that is augmented by NarL. Specifically, NarL itself was unable to bind to the narK2, acg, and Rv3130c promoters in phosphorylated or unphosphorylated form; however, its interaction with DevR similar to P resulted in cooperative binding, thereby enabling co-regulation of these genes. These findings support the role of physiologically derived nitrite as a metabolic signal in mycobacteria. We propose NarL-DevR binding, possibly as a heterodimer, as a novel mechanism for co-regulation of gene expression by the DevRS/DosT and NarL/NarS regulatory systems.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOLOGICAL CHEMISTRY
Publisher:	AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Additional Information:	Copy right for this article belongs to the AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA
Keywords:	2-COMPONENT SIGNAL-TRANSDUCTION; ESCHERICHIA-COLI K-12; NITRIC-OXIDE; HYPOXIC RESPONSE; HUMAN MACROPHAGES; DORMANCY REGULON; CARBON-MONOXIDE; PROTEIN-KINASE; DOSR; SYSTEM
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	28 Apr 2015 07:50
Last Modified:	28 Apr 2015 07:50
URI:	http://eprints.iisc.ac.in/id/eprint/51434

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