FIG. 3.

Binding of hPRP31 to the U4 snRNA requires residues in α-helix 3 of 15.5K. GST-hPRP31 was incubated with ³²P-labeled U4 snRNA in the presence (lanes 2, 3, 4, 5, 6 and 7) or absence (lane 1) of either wild-type or mutant 15.5K. GST-hPRP31 was isolated using glutathione resin, and bound RNA was extracted and ethanol precipitated. The bound (GST-hPRP31) and unbound RNA (10% supernatant [10% Sup.]) was analyzed on a denaturing 8% polyacrylamide-7 M urea gel and visualized by autoradiography. The identity of the 15.5K protein used is indicated above each lane (15.5K-Wt, wild-type 15.5K).