FIG. 3.

The A. tumefaciens ccrM promoter has a highly conserved sequence and is bound by the CtrA response regulator. (A) Sequence of the ccrM promoter region and its alignment with the ccrM promoters of C. crescentus and B. abortus. The conserved CtrA binding site (consensus, TTAANTTAAC) is in bold type. The region protected from DNase I by phosphorylated CtrA is shaded. (B) Start site of ccrM transcription as determined by primer extension. A sequence ladder generated with the same primer was used to determine the start site. (C) DNase I protection of the ccrM promoter by CtrA. A sequence ladder generated by using the primer AgMTFP1 was used to identify the protected region. Protection was seen only if CtrA was phosphorylated by the histidine kinase EnvZ.