Figure 9.

Influence of Ssr9 on Asr9 stability. The decay of Asr9 sRNA after blocking transcription by addition of rifampicin was determined by northern blots in RNA samples obtained from cultures of strains KT2440 (panel A), or F1 containing or lacking plasmids including the translational fusions 8C, 8C + S, or the asr9 gene (panel B). Values indicate the percentage of Asr9 observed at each time relative to time zero, normalized for the amount of 5S rRNA detected (values correspond to the mean for three independent assays). (C) Examples of Northern blots used to monitor the decay of Asr9 in each strain. The time (in min) at which cell samples were collected after rifampicin addition is indicated. The well named ‘F1’ corresponds to RNA obtained from strain F1 (which does not contain Asr9), which was used as control. The bands corresponding to Asr9 and 5S rRNA are indicated.