FIGURE 2.

Lead-induced and RNase A cleavage protection of CRISPR repeat RNA by P. furiosus Cas6. (A) 3′-end-labeled P. furiosus CRISPR repeat RNA was incubated in the absence (RNA) or presence of increasing concentrations of Cas6 (indicated as micromolar, μM) and subjected to RNase A cleavage (left panel) or lead-induced cleavage (right panel). RNAs were separated on 15% denaturing (7 M urea) polyacrylamide gels. Size markers include 5′-end-labeled RNA markers (M) and alkaline hydrolysis ladders (OH). (Blue bars) Sites of strong protection. (B) Cleavage protection assays performed as in A with 5′-end-labeled CRISPR repeat RNA. A summary of cleavage protections is displayed to the right of each gel. (C) A summary of observed cleavage protection is shown. The Cas6 cleavage site is indicated by an asterisk (*).