Figure 7.

Strong cleavage of the hbsΔ mRNA at nt +12 by RNase Y in the absence of initiating ribosomes. (A) Primer extension of total RNA isolated from ΔrnjA strains carrying the hbsΔ SDwt, and hbsΔ noSD and hbsΔ noAUG mutant plasmids (n = 1), using primer CC1924 hybridising to just downstream of the start codon. C2 and C3 cleavage sites are shown, in addition to the 5′ ends corresponding to the P3Δ and P1Δ transcription start sites. The sequence is labeled as its complement to facilitate direct readout. (B) Northern blot of total RNA isolated from ΔrnjA strains carrying the hbsΔ SDwt, and hbsΔ noSD and hbsΔ noAUG mutant plasmids (n = 2). The blot was probed with oligo CC1924 (hbs) and then HP246 (5S rRNA) as a loading control.