FIG. 7.

The phosphorylated Crr is involved in rpoS translation. (A) Effect of cAMP on cellular ς^S content. Strains CU263 (wild type [WT]), CU330 (crr::kan), and NM23 (cya::kan) were grown at 37°C in Luria broth in either the absence (−) or the presence (+) of 5 mM cAMP. At the mid-logarithmic phase, total protein samples were prepared and each 20 μg was subjected to immunoblotting with anti-ς^S antiserum. (B) Effect of the addition of cAMP on rpoS-lacZ PF212 expression. Strains CU264 (wild type), NM9 (crr::kan), and NM24 (cya::kan), each carrying rpoS-lacZ PF212, were grown, and then β-galactosidase activity expressed by rpoS-lacZ PF212 was measured. The data are means with standard deviations for four independent assays. (C) Strains CU263 (wild type) and CU330 (crr::kan) harboring plasmid pTSV28 (vector [vec.]), pSTCRR (crr⁺), or pST172 (crrH90Q) were grown at 37°C in Luria broth supplemented with 25 μg of chloramphenicol per ml in either the absence (−) or the presence (+) of 5 mM cAMP. At the mid-logarithmic phase, ς^S content was measured by immunoblotting.