Figure 4.

(A) Schematic of U12 snRNA showing the sequence and predicted secondary structure of WT SLIIa (nucleotides 32–53). Mutations made in the SLIIa region of U12 snRNA are illustrated. (B) Splicing phenotypes of P120 branch site UC84/85AG mutant co-expressed with the indicated SLIIa mutants of U12 snRNA. Lane numbers 1 through 6 correspond to mutants 1 through 6 shown in (A). (C) Quantitative analysis of spliced/unspliced phenotypes from the gel image shown in (B). (Rev Compl., reverse complementary; Compl., complementary).