FIG. 8.

In vitro endoribonucleolytic cleavage of TBSV genomic (+)RNA by RNase MRP. (A) Increasing amounts of highly purified RNase MRP were added to unlabeled TBSV gRNA, followed by primer extension and denaturing PAGE analysis. The primer extension was performed with labeled 708R primer. Bands representing mapped endoribonucleolytically cleaved products are marked with arrows. We used a 5′-phosphorylated 100-bp ladder (NE Biolabs) and a 25-bp ladder (Gibco-BRL) as markers. (B) Similar cleavage-site mapping experiment to that in panel A, except that the primer extension was performed with labeled RIII (3820) primer. (C) Locations of mapped endoribonucleolytic cleavage sites in TBSV gRNA. Note that we show only the more frequent/repeatable endoribonucleolytic cleavage sites and their approximate locations.