title: Control of CydB and GltA1 expression by the SenX3 RegX3 two component regulatory system of Mycobacterium tuberculosis.
abstract: Two component regulatory systems are used widely by bacteria to coordinate changes in global gene expression profiles in response to environmental signals. The SenX3-RegX3 two component system of Mycobacterium tuberculosis has previously been shown to play a role in virulence and phosphate-responsive control of gene expression. We demonstrate that expression of SenX3-RegX3 is controlled in response to growth conditions, although the absolute changes are small. Global gene expression profiling of a RegX3 deletion strain and wild-type strain in different culture conditions (static, microaerobic, anaerobic), as well as in an over-expressing strain identified a number of genes with changed expression patterns. Among those were genes previously identified as differentially regulated in aerobic culture, including ald (encoding alanine dehydrogenase) cyd,encoding a subunit of the cytochrome D ubiquinol oxidase, and gltA1, encoding a citrate synthase. Promoter activity in the upstream regions of both cydB and gltA1 was altered in the RegX3 deletion strain. DNA-binding assays confirmed that RegX3 binds to the promoter regions of ald, cydB and gltA1 in a phosphorylation-dependent manner. Taken together these data suggest a direct role for the SenX-RegX3 system in modulating expression of aerobic respiration, in addition to its role during phosphate limitation.
authors.affiliation: Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom.
authors.forename: Gretta
authors.initials: G
authors.lastname: Roberts
authors.forename: Indumathi S
authors.initials: IS
authors.lastname: Vadrevu
authors.forename: Murty V
authors.initials: MV
authors.lastname: Madiraju
authors.forename: Tanya
authors.initials: T
authors.lastname: Parish
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009876:Operon; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D011994:Recombinant Proteins