FIG. 2.

Effect of Crc on expression of the benzoate degradation pathway. The expression of the benA, catB, and pcaI genes was evaluated by real-time RT-PCR analysis of cells growing exponentially in LB medium in the absence or presence of either benzoate (Ben) or catechol (Cat). (A) The Crc repression factor was calculated by comparing mRNA levels (see Materials and Methods) for each gene in strain KT2442-C (which contains an inactivated crc allele) to those observed in the parental strain KT2442 (which contains wild-type crc). (B) Values of induction by benzoate or catechol corresponded to the mRNA levels observed for the indicated genes in cells of strain KT2442 (wild type [wt]) and KT2442-C (crc) growing in the presence of benzoate or catechol relative to those observed in these strains in the absence of benzoate or catechol.