(A) Effect of mutation in 3′ exoribonuclease genes on generation of shorter transcripts. TM542 (ΔsgrS), TM894 (ΔsgrS Δpnp), TM895 (ΔsgrS Δrnb), and TM896 (ΔsgrS Δrnr) cells harboring pSgrS-S-LS2 were grown in LB medium containing 0.2% arabinose. At A600 = 0.6, total RNAs were prepared and 10 µg of RNA samples was subjected to Northern blotting using the SgrS-S probe. (B,C) Stability of heterogeneous transcripts in the presence (C) and absence (B) of stress. TM772 (ΔsgrS Δhfq) cells harboring pSgrS-S-LS2 were grown in LB medium. For the preparation of samples in the absence of stress, 0.2% arabinose was added at A600 = 0.6 and incubation was continued for 10 min, and then rifampicin (250 µg/mL) was added. Total RNAs were prepared at the indicated time after the addition of rifampicin. For the preparation of samples in the presence of stress, cells were exposed to 0.01% αMG for 10 min prior to the addition of arabinose. The RNA samples (20 µg) were subjected to Northern blotting using the SgrS-S. Arrowheads represent the full-length transcripts.
