Sustained Staufen1 expression regulates CELF1 and MBNL1 levels and alternative splicing in wild-type skeletal muscle. (A and B) H&E staining of TA muscle cross-section from 16-week-old wild-type FVB/N (CTL) and MCK-Stau1 mice (Tg-551 and Tg-6898). Scale bars, 50 μm. (C and D) Alternative splicing profiles from 16-week-old wild-type FVB/N (CTL) and MCK-Stau1 mice were analyzed by RT-PCR. The quantification of Serca1 exon 22 exclusion and RyR1 ASI exon 70 exclusion. (E and F) Western blot and quantification from TA muscles of 16-week-old wild-type FVB/N (CTL) and MCK-Stau1 mice for CELF1, MBNL1 and β-actin and GAPDH as the loading control. CTL (N = 5) and MCK-Stau1 (N = 6). (G) The quantification of CELF1 and MBNL1 mRNA expression by RT-qPCR. CTL (N = 5) and MCK-Stau1 (N = 6). Data are means ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001; Student’s t-test, two-tailed, equal variance.