FIG. 1.

Major expression patterns of the downregulated genes in R. sphaeroides in response to blue light. Clusters were derived by using GeneSpring software. (A) Cluster 1 represents genes whose expression was downregulated at 5 min of irradiation and remained low during irradiation. (B) Cluster 2 represents genes whose expression was significantly downregulated at 45 min but not at 5 min of irradiation. (C) PS gene cluster and puc operons. PpsR-binding sites are shown as red vertical arrows. Putative transcripts are shown as black horizontal arrows. Colors: green, bacteriochlorophyll biosynthesis genes; red, carotenoid biosynthesis genes; blue, genes encoding structural polypeptides of photocomplexes; gray, genes encoding assembly factors or proteins of unknown function; orange, genes encoding regulatory factors; pink, genes encoding enzymes common to bacteriochlorophyll and ubiquinone biosynthesis. Circled genes were directly repressed by PpsR (Moskvin et al., submitted). (D) Relative expression of the PS genes in the ΔappA mutant APP11 and the wild type expressing higher levels of PpsR, 2.4.1(pPNs), compared to the wild-type strain. The expression of every gene in the wild type (not shown) was assigned to 1. The expression levels in APP11 and 2.4.1(pPNs) are according to the color scheme shown.