The pAM beta 1 CopF repressor regulates plasmid copy number by controlling transcription of the repE gene.
pAM beta 1 is a low-copy-number, promiscuous plasmid from Gram-positive bacteria that replicates by a unidirectional theta-type mode. Its replication is initiated by an original mechanism, involving the positive rate-limiting RepE protein. Here we show that the pAM beta 1-encoded CopF protein is involved in negative regulation of the plasmid copy number. CopF represses approximately 10-fold the transcription initiated at the promoter of the repE gene and binds to a 31 bp segment which is located immediately upstream of the -35 box of the repE promoter. We propose that CopF inhibits initiation of transcription at the repE promoter by binding to its operator.
Le Chatelier
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Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, Jouy en Josas, France.
Ehrlich
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SD
Jannière
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D001412:Bacillus subtilis / Q000235:genetics*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005784:Gene Amplification; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D010957:Plasmids / Q000235:genetics*; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D004269:DNA, Bacterial