Abstract

Significance Skeletal muscle exhibits a remarkable ability to regenerate, a process that has been demonstrated to be dependent on satellite cells. Satellite cells uniformly express the transcription factor paired box 7 (Pax7), and extensive analysis of Pax7 -deficient mice has documented the progressive loss of the satellite cell lineage likely due to a failure to proliferate together with precocious differentiation. In contrast to these findings, a recent provocative study suggested that Pax7 was entirely dispensable in adult life. Here, we demonstrate that Pax7 expression is an absolute prerequisite for the normal function of satellite cells during regenerative myogenesis at any age. Our experiments therefore demonstrate that Pax7 plays an essential role in regulating the myogenic potential and function of satellite cells.