Ndel1 is a direct MBNL1 splicing target. (A) Semiquantitative RT-PCR analysis of alternative exon presence in Ndel1, Mff, Picalm, and Uso1 gene transcripts in GFP-sorted cultured day1 (D1) and day 2 (D2) cells infected with shLuc (C) or shMbnl1-1 (KD). Bar graphs show the percentage of the inclusion isoform based on quantification of inclusion and exclusion band intensities. (B) Genome tracks showing the computed positions of MBNL1 binding clusters in the introns of the Mff and Picalm transcripts relative to the alternatively skipped exon. (C) Genome track showing the computed position of the MBNL1 binding clusters on the introns of Ndel1 SE event and the regions probed by the RIP experiment. (D) Western blot of MBNL1 protein in control IgG and anti-MBNL1 immunoprecipitations of a total cell lysate. (E) PCR analysis of Ndel1 intronic regions in IgG and MBNL1 immunoprecipitated cell lysates. (F) Schematic of the bichromatic splicing reporter assay; wild-type Ndel gene depicted on the left and the form with a mutation in the predicted Mbnl1 binding site on the right. (G) Fluorescent microscopy images of MBNL1-Ndel1-minigene reporter assay. (H) Quantification of the fold induction of Ndel1-inc-dsRed reporter signal derived from FACS analysis.