Figure 6

Effects of M1 and M2 mutations in the brb genes 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; brz S9, strain brz S9; brb M1, strain brb M1; brz S9brb M2, strain brz S9brb M2. According to densitometry, the levels of bop mRNA (normalized to 16S rRNA) from strain brzS9 were: 58 ± 1% (OD₆₀₀ = 07.-0.8), 20 ± 2% (OD₆₀₀ = 1.1-1.2) of WT in the dark, and 46 ± 3% (OD₆₀₀ = 07.-0.8), 10 ± 1% (OD₆₀₀ = 1.1-1.2) in the light; from strain brbM1 they were: 95 ± 2% (OD₆₀₀ = 07.-0.8), 129 ± 2% (OD₆₀₀ = 1.1-1.2) of WT in the dark, and 82 ± 2% (OD₆₀₀ = 07.-0.8), 105 ± 7% (OD₆₀₀ = 1.1-1.2) in the light; and from the brzS9brbM2 they were: 74 ± 2% (OD₆₀₀ = 07.-0.8), 47 ± 2% (OD₆₀₀ = 1.1-1.2) of WT in the dark, and 64 ± 3% (OD₆₀₀ = 07.-0.8), 33 ± 3% (OD₆₀₀ = 1.1-1.2) in the light. Panel B shows the locations of mutations in the brz and brb genes.