FIGURE 2.

RNase III cleaves within the rpoS leader in vitro. In vitro transcribed RpoSII RNA (nucleotides −564 to +161) was incubated alone (lane 1) or with increasing quantities of RNase III (lanes 2–6) in the (A) absence or (B) presence of DsrA. The resulting products of cleavage were further analyzed by primer extension. (C) The RNA sequence of a segment of the rpoS 5′-leader is schematically depicted at the bottom. The elements of the inhibitory stem–loop structure (stems I, II, and III) and the ribosome-binding site (underlined) are indicated. The positions of DsrA-independent (−15/−94) and DsrA-dependent (−112/*) RNase III cleavage were determined using a concurrently run RNA sequencing ladder (lanes 7–10) and are indicated by arrows.