Updated project metadata. Muscle formation is a coordinated process driven by extensive gene expression changes where single cells fuse together to form multinucleated muscle fibers. Newly synthesized mRNAs are then regulated by RNA binding proteins(RBPs)affecting post-transcriptional transcripts metabolism. We determined how large gene expression changes affect the catalog of RBPs by studying proliferating and differentiated muscle cells in healthy and dystrophic conditions. Transcriptomic analysis showed that the expression of more than 7000 genes was affected during myogenesis. We identified 769 RBPs, of which 294 were muscle specific and 49 were uniquely shared with cardiomyocytes. A subset of 32 RBPs (half of which was muscle specific) showed preferential loading on target mRNAs in either myoblasts or myotubes. A large proportion of catalytic proteins was bound to mRNAs even though they lack classical RNA binding domains. Finally we show how the identification of cell specific RBPs enabled the identification biomarkers that can separate healthy individuals from dystrophic patients. Our data show how interactome data can shed light on new basic RNA biology as well as provide cell specific data that can be used for diagnostic purposes.