Regulation of the divergent guaBA and xseA promoters of Escherichia coli by the cyclic AMP receptor protein.
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Hutchings MI, Drabble WT
Regulation of the divergent guaBA and xseA promoters of Escherichia coli by the cyclic AMP receptor protein.
FEMS Microbiol Lett. 2000 Jun 15;187(2):115-22.
- PubMed ID
- 10856643 [ View in PubMed]
- Abstract
The gua promoter (guaP) of Escherichia coli resembles those for ribosomal RNA (rrn) operons and lies in a close back-to-back arrangement with the promoter for xseA (xseP). Transcription from guaP is subject to stringent control and growth-rate-dependent regulation, and to repression by DnaA and PurR. In addition, transcription from guaP is regulated by the cyclic AMP receptor protein (CRP). Plasmid-borne promoter fusions to the receptor gene for chloramphenicol acetyl transferase were used to assess the role of CRP in controlling transcription from guaP and xseP following a downshift of cultures from rich into minimal medium. CRP is required to activate guaBA transcription and repress xseA transcription following downshift. Bandshift assays with a DNA fragment carrying the divergent promoters revealed specific binding of CRP. We propose that CRP, binding to a near-consensus site centred at -117.5, activates transcription from guaP and obstructs transcription from the xseA promoter.