Figure 2.

In100 requires the context of competing splice sites. (A) Structure of splicing substrates. The thinner line and shaded rectangle represent β-globin sequences substituted in the C2/C3Gloi2 substrates. The gray box in parentheses depicts the presence or the absence of the In100 element. The table shows the splicing efficiency (%) as determined from three independent experiments. (B) Splicing of Ex9–10 substrates. Substrates were incubated in HeLa nuclear extracts for the time (in hours) indicated above each lanes. (C) Splicing of Ex8–10 substrates. (D) Splicing of 553 derivatives. Position of the splicing products generated from the use of the proximal (Prox.) or distal (Dist.) splice site is indicated by the white or black triangles, respectively. (E) Splicing of the (C2/C3)Gloi2 derivatives in transfected HeLa cells. Position of exon 9 inclusion and skipping mRNAs is shown.