Figure 1.

Inhibition of spliceosome complex formation by the BPV-1 ESS in vitro. The two pre-mRNAs used for the assay are shown diagrammatically at the top of the gel. The cross-hatched box in exon 2 indicates SE1; the black box in exon 2 indicates the ESS. Spliceosomal complex formation was carried out and analyzed as described in Materials and Methods. The 0 time indicates the pre-mRNA with no addition of HeLa NE. Spliceosomal complexes A and B, the nonspecific heterogeneous nuclear ribonucleoprotein complex H, and free pre-mRNA are indicated on the left of the gel. Ori, origin.