FIG. 4.

Gel retardation analysis of TCV CP binding to RNA fragments. (A) TCV CP binding to the C3′ (64 nt), C56G3′ (66 nt) and SK70 (70 nt) RNAs. ³²P-labeled RNAs (100 pM) were incubated in the presence of a series of increasing concentrations of CP, indicated above each gel. Incubation mixtures were subjected to electrophoresis on a 5% polyacrylamide gel that was fixed and dried prior to autoradiography. (B) Quantification of the results presented in panel A and two additional independent experiments (data not shown). Autoradiograms were scanned by densitometry, and the fractions of unbound RNA remaining in the presence of different CP concentrations were determined and plotted against CP concentrations. Each point represents the average of three experiments. Standard deviation bars that are not within the limits of the symbols are shown.