FIGURE 3.
Point mutations in the three elements affect Bcl-x splicing in HeLa cells. A, mutations for every two nucleotides are represented in lowercase below the wild-type sequence. Shown in the graph are Bcl-xL/Bcl-xS ratios for each mutation, relative to the Bcl-xL/Bcl-xS ratio of the minigene X2.13 which is represented by the horizontal line at 1.0. The nucleotides deemed important are highlighted in gray, and the putative binding sites for ASF/SF2 (B1AG and B1d) and SRp40 (B1u) are underlined. The RBM25-binding site recently discovered is boxed. B, topological map representing the average of the effect of the mutational analysis. The value for each mutation was calculated as an average of it and both adjoining mutations. For example, the value for mutation B1d.7 is an average of the values in A for the mutations B1d.6, B1d.7, and B1d.8.