Escherichia coli RNase E and RNase G cleave a Bacillus subtilis transcript at the same site in a structure-dependent manner

The decay of Bacillus subtilis aprE leader-lacZ mRNA was examined in Escherichia coli wild-type and in mutants deficient in RNase E, RNase G, or both. Two versions of the mRNA were studied: the wild-type mRNA, which has a stem-loop at the 5' end, and a mutant mRNA, with a single-stranded 5' end. The half-life of both transcripts was determined by RNase E, the half-life of the mutant transcript being one-third of that of the wild-type transcript. RNase G cleaved both transcripts at a site within an AU-rich sequence in the stem-loop region, but cleavage was much more efficient when the stem-loop was destabilized. RNase E cleaved at the same site, but less efficiently and only in the mutant transcript.