Saturation mutagenesis scheme. (A) Minigene used for splicing studies. The central exon target was Wilms' tumor gene 1 exon 5. All ATG triplets were removed from dhfr exon 1 to minimize the chance of nonsense-mediated decay (NMD). A Kozak ATG sequence was added to dhfr exon 3 to allow mRNA to associate with polysomes. (B) Mutagenesis scheme. At each exon position from 2 to 47, all possible DBSs and SBSs were represented. (C) The input libraries as PCR products and the output libraries as amplified cDNA were deep-sequenced, and the ratio of the relative abundance of these output mutant molecules to the corresponding input abundance was designated the enrichment index (EI).
