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J Bacteriol

Title:		Competence for genetic transformation in Streptococcus pneumoniae: termination of activity of the alternative sigma factor ComX is independent of proteolysis of ComX and ComW
Author(s):		Piotrowski A; Luo P; Morrison DA;
Address:		"Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607, USA"
Journal Title:		J Bacteriol
Year:		2009
Volume:		20090313
Issue:		10
Page Number:		3359 - 3366
DOI:		10.1128/JB.01750-08
ISSN/ISBN:		1098-5530 (Electronic) 0021-9193 (Print) 0021-9193 (Linking)
Abstract:		"Competence for genetic transformation in Streptococcus pneumoniae is a transient physiological state whose development is coordinated by a peptide pheromone (CSP) and its receptor, which activates transcription of two downstream genes, comX and comW, and 15 other 'early' genes. ComX, a transient alternative sigma factor, drives transcription of 'late' genes, many of which are essential for transformation. In vivo, ComW both stabilizes ComX against proteolysis by the ClpE-ClpP protease and stimulates its activity. Interestingly, stabilization of ComX by deletion of the gene encoding the ClpP protease did not extend the period of competence. We considered the hypothesis that the rapid decay of competence arises from a rapid loss of ComW and thus of its ComX stimulating activity, so that ComX might persist but lose its transcriptional activity. Western analysis revealed that ComW is indeed a transient protein, which is also stabilized by deletion of the gene encoding the ClpP protease. However, stabilizing both ComX and ComW did not prolong either ComX activity or the period of transformation, indicating that termination of the transcriptional activity of ComX is not dependent on proteolysis of ComW"
Keywords:		"Bacterial Proteins/genetics/*metabolism Blotting, Western Electrophoresis, Polyacrylamide Gel Endopeptidase Clp Models, Biological Protein Stability Serine Endopeptidases/genetics/metabolism Sigma Factor/genetics/*metabolism Streptococcus pneumoniae/*gene;"
Notes:		"MedlinePiotrowski, Andrew Luo, Ping Morrison, Donald A eng Research Support, U.S. Gov't, Non-P.H.S. 2009/03/17 J Bacteriol. 2009 May; 191(10):3359-66. doi: 10.1128/JB.01750-08. Epub 2009 Mar 13"