FIG. 3.

PCBP dissociates from stem-loop IV in the presence of cloverleaf RNA and 3CD. Uniformly labeled stem-loop IV (5 ng) was incubated with buffer, unlabeled cloverleaf RNA (500 ng, lane 2), S10 HeLa proteins (20 μg), and decreasing concentrations of unlabeled cloverleaf (CL) RNA (500, 50, and 5 ng) (lanes 4 to 6 and lanes 7 to 9). Binding reactions were performed in the absence (lanes 3 to 6) or in the presence (lanes 7 to 10) of 0.5 μg of recombinant 3CD. The electrophoretic mobility of the two RNP complexes formed between PCBP and stem-loop IV (complex I and complex II) and the free stem-loop IV RNA (Free Probe) is indicated on the left.