C-rich motifs function as ISEs in LCAT intron 4 splicing. (a) LCAT intron 4 with the mutations shown in blue above the WT sequence. BPS, branchpoint. (b) Splicing of the LCAT intron 4 mini-genes (WT, MUT1, MUT1b, MUT2, MUT 6 and MUT 5) in HeLa cells. Analysis was performed as in Figure 4. (c) Graphical representation of the percent pre-mRNA for each LCAT mini-gene. Error bars represent standard deviation of replicate experiments.