The Role of SOX7 in the Activation of Satellite Cells and Regulation of Skeletal Myogenesis

Abstract

One of the major drawbacks of using stem cell therapy to treat muscular dystrophies is the challenge of isolating sufficient numbers of suitable precursor cells for transplantation. As such, a deeper understanding of the molecular mechanisms involved during muscle development, which would increase the proportion of embryonic stem cells that can differentiate into skeletal myocytes, is essential. In conditional SOX7-/- mice, we observed that the loss of SOX7 in satellite cells resulted in poor differentiation and fusion. In vivo, we observed fewer Pax7+ satellite cells in the mice lacking SOX7 as well as smaller muscle fibers. RT-qPCR data also revealed that Pax7, MRF and MHC3 transcript levels were down-regulated in SOX7 knockdown mice. Surprisingly, when SOX7 was over-expressed in embryonic stem cells, we found that there was a defect in making muscle precursor cells, specifically a failure to activate Pax7 expression. Taken together, these results suggest that SOX7 expression is required for the proper regulation of skeletal myogenesis.