Identification of DNA binding sites for ComE, a key regulator of natural competence in Streptococcus pneumoniae.
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.
Ween
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Department of Chemistry and Biotechnology, Agricultural University of Norway, PO Box 5040, N-1432 As, Norway.
Gaustad
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Håvarstein
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D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000378:metabolism; D014169:Transformation, Bacterial
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C103179:ComE protein, Streptococcus pneumoniae; D015342:DNA Probes; D004268:DNA-Binding Proteins