FIG. 7.

Recombinant SF3a66 and SF3a120 bind RNA. Full-length SF3a60, SF3a66, and SF3a120 (A) or full-length and mutant SF3a66 proteins (B) were UV cross-linked to synthetic [α-³²P]UTP-labeled RNA, treated with RNases A and T₁, and separated by SDS-PAGE. The gel was dried and exposed to X-ray film. The positions of SF3a66 and SF3a120 are shown. Asterisks indicate binding of unrelated proteins. Molecular mass standards (in kilodaltons) are shown on the left.