Celf1 is directly phosphorylated and regulated by Akt and cyclin D3/cdk4, which leads to CCND1 upregulation and p21 downregulation and causes impaired myogenesis in DM1 (Timchenko et al., 2001a; Salisbury et al., 2008). This evidence concerns the gene CELF1 and myotonic dystrophy type 1.