Figure 4

Effects of inactivation of the brb gene translation on bop transcription. In panel A, the upper blocks represent the 16S rRNA bands on the agarose gel stained by ethidium bromide. The lower blocks show northern blots of total cell RNA after probing with labeled DNA fragments containing the bop gene. Cells were grown in the dark and light. Culture OD₆₀₀ at which RNA was extracted is given at right. WT R1, wild-type strain R1; brb stop1, strain brb stop1; brb stop2, strain brb stop2. According to densitometry, the levels of bop mRNA (normalized to 16S rRNA) from strain brb stop1 were: 117 ± 5% (OD₆₀₀ = 07.-0.8), 86 ± 4% (OD₆₀₀ = 1.1-1.2) of WT in the dark, and 106 ± 2% (OD₆₀₀ = 07.-0.8), 132 ± 9% (OD₆₀₀ = 1.1-1.2) in the light; from strain brb stop2 they were: 175 ± 6% (OD₆₀₀ = 07.-0.8), 95 ± 4% (OD₆₀₀ = 1.1-1.2) of WT in the dark, and 124 ± 9% (OD₆₀₀ = 07.-0.8), 118 ± 11% (OD₆₀₀ = 1.1-1.2) in the light. Panel B shows locations of the mutations in the brz and brb genes.