Figure 4

6S RNA affects ribosomal RNA transcription at stationary growth. a) Primer extension analysis of bulk rRNA transcription from P1 and P2 promoters. Two independent RNA samples were analyzed from ssrS^- (-) and ssrS⁺ (+) cells grown exponentially (exp.) or stationary (stat.). cDNA products originating from P1 and P2 promoters are indicated. Multiple bands are resolved due to sequence heterogeneities of the rRNA leader regions from the seven different rRNA operons. The constitutively expressed rhoL transcript served as an internal standard for quantification. Lanes 1 and 5: RNA from ssrS^- cells at exponential growth, lanes 2 and 6: RNA from ssrS⁺ cells at exponential growth, lanes 3 and 7: RNA from ssrS^- cells at stationary growth, lanes 4 and 8: RNA from ssrS⁺ cells at stationary growth. b) Quantitative evaluation of P2 transcription products at early stationary phase from RNA samples of ssrS^- (Mutant) and ssrS⁺ (wild-type) cells is shown. Error bars give the standard deviation of 4 independent experiments.