A novel myogenic cell line with phenotypic properties of muscle progenitors.

Skeletal myogenesis is a multistep process starting with progenitor cell proliferation, followed by their exit from the cell cycle, differentiation, alignment, and fusion to form multinucleated myotubes, typical of the differentiated muscle tissue. While the molecular players involved in early myogenesis have been extensively characterized, information about the later steps of the process is scanty. Here, we describe a novel myogenic cell line (MYOP7), composed of highly proliferating Sca-1+ muscle precursor cells, which can be induced to terminally differentiate into spontaneously contracting multinucleated myotubes. By performing high-density microarray analysis on these cells, we identified a series of genes, differentially expressed in proliferating vs differentiating conditions, which are candidates to play a major role in the later phase of myogenesis. In addition, we confirmed that the late stages of muscle differentiation are characterized by a marked upregulation of the cellular receptors for the vascular endothelial growth factor.