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Identification of DNA binding sites for ComE, a key regulator of natural competence in Streptococcus pneumoniae
Author(s) -
Ween Ola,
Gaustad Peter,
Håvarstein Leiv Sigve
Publication year - 1999
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1999.01528.x
Subject(s) - biology , streptococcus pneumoniae , gene , genetics , promoter , regulator , response regulator , quorum sensing , dna , dna binding site , genome , binding site , sequence motif , transcription (linguistics) , transcription factor , gene expression , bacteria , bacterial protein , virulence , linguistics , philosophy
Natural competence in Streptococcus pneumoniae is regulated by a quorum‐sensing mechanism consisting of a competence‐stimulating peptide (CSP), its dedicated secretion apparatus (ComAB), its histidine kinase receptor (ComD) and a response regulator (ComE). In this report, we show that ComE is a DNA‐binding protein that acts autocatalytically by binding to a region in its own promoter. Two additional ComE binding sites were identified in the pneumococcal genome, one in the promoter region of comAB and the other upstream of an ABC transporter of unknown function. A comparison of the ComE‐binding sequences with the sequence motif previously found to be involved in the co‐ordinated expression of the late genes revealed that they are unrelated. These findings indicate that ComE activates transcription of the late genes indirectly, i.e. via one or more intermediate factors.