FIG. 4.

Heat induction of the SigB-dependent gsiB gene. Total RNA was isolated from cultures of the wild-type strain 168 and its isogenic mutant derivatives grown at 37 and 51°C, electrophoretically separated on an agarose gel, blotted onto a nylon membrane, and hybridized with a single-stranded RNA probe specific for gsiB. Lanes 1 and 2, strain BSM24 (rsbV); lanes 3 and 4, strain BSM29 (sigB); lanes 5 and 6, wild-type strain 168. Lanes 1, 3, and 5, total RNA isolated from cultures grown at 37°C; lanes 2, 4, and 6, total RNA isolated from cultures grown at 51°C.