G-rich and C-rich motifs can functionally replace one another as ISEs. (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, MUT3, MUT7, MUT6, MUT 27, MUT 28 and MUT 29) 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.