Figure 1.

SF2/ASF binds to the HIV Rev/RRE complex. (A) REMSA autoradiograms are shown in which various amounts of the precipitate from a 65–90% NH₄2SO₄-saturated fraction of HeLa cell nuclear extract were added to Rev-binding reactions performed with ³²P-radiolabeled sense and RRE (Right) and control (Left) RNA probes (18). The C1 and C2 complexes formed by Rev binding to the RRE are shown. (B) REMSA demonstrating specific binding of the Rev/RRE complex to SF2/ASF renatured after purification from HeLa cell nuclei by preparative SDS/PAGE (17). In lanes 3 and 4, 300 ng of SF2/ASF was used in reactions. (C) REMSA with 900 ng of recombinant SF2/ASF purified from baculovirus-infected Sf9 cells (21). Binding reactions were performed as described in Materials and Methods.