Effect of depletion of PRR33 on gene expression during myoblast differentiation

Coordinated cytoskeleton-mitochondria organization during myogenesis is very essential for muscle development and function. Currently, our understanding of the underlying regulatory mechanisms is still inadequate. Here, we identified a novel muscle specific protein PRR33, which is up-regulated during myogenesis and acts as a promyogenic factor. Depletion of PRR33 in C2C12 represses myoblast differentiation. Interactome and transcriptome analyze reveal that PRR33 regulates cytoskeleton and mitochondrial function. Remarkably, PRR33 interacts with DESMIN, a key regulator of cytoskeleton-mitochondria organization in muscle cells. Abrogation of PRR33 in myocytes substantially abolishes the interaction of DESMIN filaments with mitochondria and can result in abnormal intracellular accumulation of DESMIN and mitochondrial disorganization/dysfunction in myofibers. Together, our study shows that PRR33 and DESMIN constitute an important regulatory module coordinating mitochondrial organization with muscle differentiation. To investigate the function of PRR33 in regulation of myoblast differentiation, we established C2C12 cell line which PRR33 has been knocked down through CRISPR/CAS9 gRNA. Then, we performed gene expression profiling analysis using data obtained from RNA-seq of ctrl-gRNA and Prr33-gRNA C2C12 at differentiation medium 3 days.