FIG. 5.

Depletion of HeLa cell nuclear extracts with ESSV and ESS2 RNAs removes a common inhibitory cellular factor or factors. In vitro splicing of HS1-ESSV, HS1-ESSVx, or HS1-ESS2 substrates was carried out by use of nondepleted nuclear extracts and nuclear extracts depleted with ESSV- or ESSVx-biotinylated RNAs (A) or ESS2- or ESS2x-biotinylated RNAs (B) immobilized on paramagnetic beads (Beads-RNA) as described in Materials and Methods. The positions of the precursor and the spliced product are marked.