Negative regulation of the bolA1p of Escherichia coli K-12 by the transcription factor OmpR for osmolarity response genes.

To test whether OmpR is involved in regulation of the bolA1p, we investigated possible effects of ompR mutation on transcription from bolA1p. In vivo, bolA1p was found to be repressed by OmpR. Furthermore in vitro, the phospho-OmpR was found to bind to the OmpR binding region of bolA1p and repress the transcription by Esigma(S) or Esigma(D). These results suggest that the phosphorylated form of OmpR is a negative regulator for the transcription of the bolA1p promoter.