Adaptive Mutagenesis at ebgR Is Regulated by PhoPQ
Hall, Barry G.
American Society for Microbiology
Adaptive mutations are mutations that occur in nondividing or very slowly dividing microbial cells during prolonged nonlethal selection and that are specific to the challenge of the selection in the sense that the only mutations that can be detected are those that provide a growth advantage to the cell. The phoPQ genes encode a two-component positively acting regulatory system that controls expression of at least 25 to 30 genes in Escherichia coli and Salmonella typhimurium. PhoPQ responds to a variety of environmental stress signals including Mg2+ starvation and nutritional deprivation. Here I show that disruption of phoP or phoQ by Tn10dCam significantly reduces the adaptive mutation rate to ebgR, indicating that the adaptive mutagenesis machinery is regulated, directly or indirectly, by phoPQ. The finding that it is regulated implies that adaptive mutagenesis does not simply result from a failure of various error correction mechanisms during prolonged starvation.
ACESSO AO ARTIGOhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=107250
- Spectra of Spontaneous Growth-Dependent and Adaptive Mutations at ebgR
- Transcriptional autoregulation of the Salmonella typhimurium phoPQ operon.
- Transcription of the SsrAB Regulon Is Repressed by Alkaline pH and Is Independent of PhoPQ and Magnesium Concentration
- Inactivation of phoPQ genes attenuates Salmonella Gallinarum biovar Gallinarum to susceptible chickens
- Alterations in Two-Component Regulatory Systems of phoPQ and pmrAB Are Associated with Polymyxin B Resistance in Clinical Isolates of Pseudomonas aeruginosa▿