Toxin-antitoxin systems of mycobacterium smegmatis are essential for cell survival

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dc.contributor.authorFrampton, Rebekah A.
dc.contributor.authorAggio, Rachael B.M.
dc.contributor.authorVillas-Bôas, Silas G
dc.contributor.authorArcus, Vickery L.
dc.contributor.authorCook, Gregory M.
dc.date.accessioned2013-03-11T21:12:41Z
dc.date.available2013-03-11T21:12:41Z
dc.date.copyright2012-02-17
dc.date.issued2011
dc.description.abstractThe role of chromosomal toxin-antitoxin (TA) modules in bacterial physiology remains enigmatic despite their abundance in the genomes of many bacteria. Mycobacterium smegmatis contains three putative TA systems, VapBC, MazEF, and Phd/Doc, and previous work from our group has shown VapBC to be a bona fide TA system. In this study, we show that MazEF and Phd/Doc are also TA systems that are constitutively expressed, transcribed as leaderless transcripts, and subject to autoregulation, and expression of the toxin component leads to growth inhibition that can be rescued by the cognate antitoxin. No phenotype was identified for deletions of the individual TA systems, but a triple deletion strain (ΔvapBC, mazEF, phd/doc), designated ΔTAtriple, exhibited a survival defect in complex growth medium demonstrating an essential role for these TA modules in mycobacterial survival. Transcriptomic analysis revealed no significant differences in gene expression between wild type and the ΔTAtriple mutant under these conditions suggesting that the growth defect was not at a transcriptional level. Metabolomic analysis demonstrated that in response to starvation in complex medium, both the wild type and ΔTAtriple mutant consumed a wide range of amino acids from the external milieu. Analysis of intracellular metabolites revealed a significant difference in the levels of branched-chain amino acids between the wild type and ΔTAtriple mutant, which are proposed to play essential roles in monitoring the nutritional supply and physiological state of the cell and linking catabolic with anabolic reactions. Disruption of this balance in the ΔTAtriple mutant may explain the survival defect in complex growth medium.en_NZ
dc.identifier.citationFrampton, R., Aggio, R. B. M., Villas-Boas, S. G., Arcus, V. L., & Cook, G. M. (2012). Toxin-Antitoxin Systems of Mycobacterium smegmatis Are Essential for Cell Survival. Journal of Biological Chemistry, 287(8), 5340-5356.en_NZ
dc.identifier.doi10.1074/jbc.M111.286856en_NZ
dc.identifier.issn1083-351X
dc.identifier.urihttps://hdl.handle.net/10289/7342
dc.language.isoen
dc.publisherAmerican Society for Biochemistry and Molecular Biologyen_NZ
dc.relation.isPartOfJournal of Biological Chemistryen_NZ
dc.relation.ispartofJournal of Biological Chemistry
dc.subjectBacterial Metabolismen_NZ
dc.subjectGene Expressionen_NZ
dc.subjectGene Regulationen_NZ
dc.subjectMetabolic Regulationen_NZ
dc.subjectMycobacteriaen_NZ
dc.subjectGrowth Arresten_NZ
dc.subjectToxin-Antitoxinen_NZ
dc.titleToxin-antitoxin systems of mycobacterium smegmatis are essential for cell survivalen_NZ
dc.typeJournal Articleen_NZ
pubs.begin-page1en_NZ
pubs.declined2014-06-05T17:47:37.122+1200
pubs.deleted2014-06-05T17:47:37.122+1200
pubs.elements-id36999
pubs.end-page36en_NZ
pubs.volumeonlineen_NZ
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