FIG. 2.

SR proteins are unable to affect 5′ splice site usage in duplication constructs containing the alpha-globin 5′ splice sites and neighboring G elements. The minigenes utilized for in vivo transfections contained duplicated 5′ splice sites and proximal intron sequences from either adenovirus (A) or alpha globin (B), diagramed at the top of each panel. Transfections with expression plasmids coding for either ASF-SF2 or SC35 used no (A and B, lane 1) or 0.5 (A and B, lanes 2 and 4) or 1.0 (A and B, lanes 3 and 6) μg of expression plasmid per 10-cm-diameter dish of HeLa cells. Whole-cell RNA was analyzed by RT-PCR using primers for flanking exons. RNAs resulting from usage of the proximal or distal sites (see diagrams) are indicated.