Compound 2b alleviates molecular defects in FECD cells. (A) Quantification of the number of r(CUG)exp-MBNL1 foci/nucleus (n = 3, 40 nuclei counted/replicate). (B) Quantification of the effect of 2b on MBNL1 exon 5 pre-mRNA splicing (n = 3). Statistical significance was computed by comparison to untreated cells (“0”). (C) Schematic of retention of TCF4 intron 3 in FECD-affected cells. (D) Quantification of the effect of 2b on TCF4 mature mRNA, as determined by RT-qPCR (n = 3). (E) Quantification of the effect of 2b on intron 3-containing TCF4 levels in FECD cells, compared to WT levels, as determined by RT-qPCR (n = 3). Data are represented as mean ± SD. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001, as determined by a two-tailed Student t-test (panel A) or a one-way ANOVA (panels B, D, and E). See also Figure S5.