The RNA-binding protein FXR1P regulates cell-cycle progression by modulating the expression of p21/cdkn1a/Cip1/Waf in myoblasts

ABSTRACT: The Fragile X Mental Retardation-Related 1 gene (FXR1) belongs to the Fragile X Related gene family, together with FMR1 and FXR2. While inactivation of FMR1 causes Fragile X syndrome, the most common form of inherited mental retardation, inactivation of FXR1 in various animal models suggest a critical role for the RNA-binding protein FXR1P during myogenesis. Seven alternatively spliced FXR1 transcripts have been identified, three of them being muscle-specific. We previously reported a reduction of these isoforms in myoblasts from Fascio Scapulo Humeral Distrophy (FSHD) myopathic patients. However, so far, no mRNA target of FXR1P has been linked to the drastic muscular phenotypes caused by its absence and the exact molecular role of FXR1P in muscular development remains unknown. In the present study, gene expression profiling of C2C12 myoblasts reveals that transcripts involved in cell cycle and muscular development pathways are modulated by Fxr1-depletion. In addition, Fxr1-depletion translates physiologically into a premature cell cycle exit of myoblasts, accompanied by a robust up-regulation of the cyclin-dependant kinase inhibitor p21/Cdkn1a/Waf/Cip1 mRNA. Importantly, we also observe this P21 increase in FSHD human myoblasts depleted in FXR1P muscular isoforms. Our data further indicate that FXR1P muscle-specific isoforms are involved in the post-transcriptional control of p21 mRNA levels via direct interaction with a conserved G-quadruplex structure located in its 3’ untranslated region. This study has crucial implications for the understanding of FXR1P role during myogenesis and the pathophysiology of FSHD.

ORGANISM(S): Mus musculus

PROVIDER: GSE40577 | GEO | 2013/02/01

SECONDARY ACCESSION(S): PRJNA174339

REPOSITORIES: GEO