FIG. 2.

Graphic depiction of three operons represented on the microarray. Numbers above genes indicate wild-type-to-mutant expression ratios in stationary-phase cells. Arrows indicate transcriptional start sites. (A) The four genes of the rsbV operon are transcribed from a σ^B-dependent promoter (7). Transcription can also occur from a σ^A-dependent promoter further upstream, which also transcribes the four upstream genes rsbR, rsbS, rsbT, and rsbU. (B) The four genes of the opuC operon are transcribed from a σ^B-dependent promoter (22). (C) Transcription upstream of inlA can be initiated from one of four promoters (40), one of which is σ^B dependent (as confirmed by RACE). Cotranscription of inlB can occur from at least one of the inlA promoters (40). Transcription of inlB can also occur independently from promoters directly upstream of inlB (i.e., not including inlA), including one promoter that does not have a σ^B consensus sequence (40) and potentially from one with a visually predicted σ^B-dependent promoter.