FIGURE 2.

Transcription of sifA, sifB, and sseJ is significantly de-repressed in an hns mutant at both inducing (5.8) and noninducing (7.4) pH. qRT-PCR was used to determine the extent of hns silencing of sifA, sifB, and sseJ transcript levels. Reactions were performed with the indicated gene-specific primers and RNA harvested from wild type, hns, or ssrB null strains grown in PCN minimal medium at inducing (5.8; solid bars) or noninducing (7.4; open bars) pH. Transcript levels were normalized to 16 S RNA as described under “Experimental Procedures.” Error bars represent ±1 S.D. The hns mutants required PCN minimal medium for growth and are thus not directly comparable with supplemental Fig. 1 where RNA was harvested after growth in N9 minimal medium.