eCite Digital Repository

A two-component regulator of universal stress protein expression and adaptation to oxygen starvation in Mycobacterium smegmatis


O'Toole, R and Smeulders, MJ and Blokpoel, MC and Kay, EJ and Lougheed, K and Williams, HD, A two-component regulator of universal stress protein expression and adaptation to oxygen starvation in Mycobacterium smegmatis, Journal of Bacteriology, 185, (5) pp. 1543-1554. ISSN 0021-9193 (2003) [Refereed Article]

DOI: doi:10.1128/JB.185.5.1543-1554.2003


We identified a response regulator in Mycobacterium smegmatis which plays an important role in adaptation to oxygen-starved stationary phase. The regulator exhibits strong sequence similarity to DevR/Rv3133c of M. tuberculosis. The structural gene is present on a multigene locus, which also encodes a sensor kinase. A devR mutant of M. smegmatis was adept at surviving growth arrest initiated by either carbon or nitrogen starvation. However, its culturability decreased several orders of magnitude below that of the wild type under oxygen-starved stationary-phase conditions. Two-dimensional gel analysis revealed that a number of oxygen starvation-inducible proteins were not expressed in the devR mutant. Three of these proteins are universal stress proteins, one of which is encoded directly upstream of devR. Another protein closely resembles a proposed nitroreductase, while a fifth protein corresponds to the α-crystallin (HspX) orthologue of M. smegmatis. None of the three universal stress proteins of nitroreductase, and a considerably lower amount of HspX was detected in carbon-starved wild-type cultures. A fusion of the hspX promoter to gfp demonstrated that DevR directs gene expression when M. smegmatis enters stationary phase brought about, in particular, by oxygen starvation. To our knowledge, this is the first time a role for a two-component response regulator in the control of universal stress protein expression has been shown. Notably, the devR mutant was 10 4-fold more sensitive than wild type to heat stress. We conclude that DevR is a stationary-phase regulator required for adaptation to oxygen starvation and resistance to heat stress in M. smegmatis.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Medical microbiology
Research Field:Medical bacteriology
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:O'Toole, R (Dr Ronan O'Toole)
ID Code:95796
Year Published:2003
Web of Science® Times Cited:77
Deposited By:Medicine
Deposited On:2014-10-08
Last Modified:2014-10-08

Repository Staff Only: item control page