Document Detail


CRP-dependent Positive Autoregulation and Proteolytic Degradation Regulates Competence Activator Sxy of Escherichia coli.
MedLine Citation:
PMID:  25491382     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Natural competence, the ability of bacteria to take up exogenous DNA and incorporate it into their chromosomes, is in most bacteria a transient phenomenon under complex genetic and environmental control. In the Gram-negative bacteria Haemophilus influenzae and Vibrio cholerae the master regulator Sxy/TfoX controls competence development. Although not known to be naturally competent, Escherichia coli possesses a Sxy homologue and a competence regulon containing the genes required for DNA uptake. Here, we show that in contrast to other characterised Gamma-proteobacteria, E. coli Sxy is positively autoregulated at the level of transcription by a mechanism that requires CRP, cAMP and a CRP-S site in the sxy promoter. Similarly, we found no evidence that Sxy expression in E. coli was regulated at the translational level. However, biochemical analysis revealed that Sxy is an unstable protein and that its cellular level is negatively regulated at the post-translational level via degradation by Lon protease. Interestingly, in the Gram-positive model organism Bacillus subtilis, the competence master regulator ComK is also positively autoregulated at the level of transcription and negatively regulated by proteolysis. Together, these findings reveal striking similarities between the competence regulons of a Gram-positive and a Gram-negative bacterium.
Authors:
Milena Jaskólska; Kenn Gerdes
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-12-10
Journal Detail:
Title:  Molecular microbiology     Volume:  -     ISSN:  1365-2958     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2014 Dec 
Date Detail:
Created Date:  2014-12-10     Completed Date:  -     Revised Date:  2014-12-11    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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This article is protected by copyright. All rights reserved.
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