CELF1 and myotonic dystrophy type 1: Importantly, in this experimental model of DM1, manumycin A did not alter expression of Mbnl1 and Cugbp1, which are involved in splicing regulation of Clcn1 E7a, Serca1 E22, and m-Titin Mex5 (Table S1 in Supplementary Material).