Figure 1. Microarray transcription profiles of (A) Group-I and (B) Group-II genes in wild-type S. venezuelae during submerged sporulation and in congenic ΔbldM, ΔwhiA, ΔwhiB, ΔwhiD, ΔwhiG, ΔwhiH and ΔwhiI null mutants grown under identical conditions.

RNA samples were prepared at 2-hour intervals from 8 to 20 hours, by which time sporulation was nearing completion. For each panel, the x-axis indicates the age of the culture in hours, and the y-axis indicates the per gene normalized transcript abundance (log₂). Group-I genes (blue) depend on bldM but are independent of all the whi genes. Group-II genes (red) depend on bldM but also depend whiG and whiI. The average expression profile is indicated by the black line. Group I genes are activated at least two hours earlier than Group-II genes (see insets). Red bars indicate vegetative growth (V), fragmentation of mycelium (F), and spore formation (S).