Rbfox1 Downregulation and Altered Calpain 3 Splicing by FRG1 in a Mouse Model of Facioscapulohumeral Muscular Dystrophy (FSHD)
(a) Left panel: real-time RT-PCR analysis showing that in FRG1 mice Rbfox1 expression is preferentially downregulated in vastus lateralis compared to biceps brachii. Gapdh expression was used for sample normalization. Right panel: immunoblotting on vastus lateralis using anti-Rbfox1 antibody. Tubulin was used as loading control and FRG1 antibody as confirmation of the genotype. (b) Real-time RT-PCR analysis showing that Rbfox1 expression is normal in mdx mice. (c) Left: real-time RT-PCR analysis showing that Rbfox1 expression is down-regulated in proliferating (MB) or differentiating (MT) C2C12 muscle cells over-expressing FRG1. Right: immunoblotting using protein extracted from the same samples as in (c, left) using anti-Rbfox1 antibodies. Tubulin was used as loading control. Note that in proliferating C2C12 cells Rbfox1 protein is almost undetectable, while its levels significantly increase during myogenic differentiation. (d) Left panel: real-time RT-PCR analysis of RBFOX1 expression using RNA extracted from muscle cells derived from three different normal individuals and three different FSHD patients. Right panel: immunoblotting using protein extracted from the same samples as in (d, left) using anti-RBFOX1 antibody. Tubulin was used as loading control.