Gel mobility shift assay
of RB69 RegA protein binding to RE RNAs. 32P-5′-end-labeled
18mer RB69 gene 44 RE RNA (5′-AUGAGGAAAAUUACAUGA-3′) (lanes 1–4), 16mer T4 gene 44 RE RNA (5′-AAUGAGGAAAUUAUG-3′) (lanes 5–7) and 16mer T4 gene 44 G–9U RE RNA (5′-AAUUAGGAAAUUAUG-3′) (lanes
8–10) were incubated with cell supernatants containing
no RegA protein (lane 2) or 20 nM RB69 RegA protein (lanes 3, 4,
6, 7, 9 and 10). Samples were analyzed by electrophoresis on a native
6% polyacrylamide gel. Gels were dried and then analyzed
on a PhosphorImager (see Materials and Methods).