Figure 7.

PCC 7002 RNase III’s are capable of cleaving E. coli RNase III targets. (A) Cleavage assays of in vitro transcribed E. coli RNase III target (aceEF) incubated with purified cyanobacteria RNase III’s. Cleavage reactions containing 5 μg of RNA were initiated by addition of MgCl₂ and samples were removed at 5, 10, 20, 30 and 60 min and run on a urea polyacrylamide gel. Initial samples were also taken before the addition of enzyme (–/–) and MgCl₂ (+/-). (B) Summary of cleavage reactions of sequences known to be cleaved by E. coli’s RNase III. A highly structured RNA but not known to be cleaved by E. coli’s RNase III was included as a negative control (ompA). (C) Locations of cyanobacteria RNase III cleavage of known E. coli RNase III targets. Structures and locations of E. coli RNase III cleavage are shown as in (21). Filled in triangles indicate 5′ ends found with 5′ RACE of in vitro cleavage reactions while open triangles indicate position of the other cleavage event where the inferred other cleavage event would be to leave the characteristic two nucleotide 3′-overhangs.