title: Pax7 is back.
abstract: Two recent studies have reinvigorated the conversation regarding the role of Pax7 in adult satellite. Studies by Gunther et al (Cell Stem Cell 13:590-601, 2013) and Von Maltzhen et al (Proc Natl Acad Sci U S A 110:16474-16479) show that Pax7 is critical for adult satellite cell function and their contribution to muscle repair. Previously, Lepper et al (Nature 460:627-631, 2009) demonstrated that Pax7 was dispensable for adult muscle repair. In this commentary I have summarized the results from these studies, focusing on the differences in experimental paradigms that led the authors to different conclusions. I also take this opportunity to discuss the potential limitations and hurdles of Cre-lox technology that are responsible for the discrepant results.
authors.affiliation: Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA 02114 USA ; Harvard Stem Cell Institute (HSCI), Boston, MA 02114 USA ; Harvard Medical School, Boston, MA 02115 USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Brack
keywords: Cre; Lineage tracing; Pax7; Regeneration; Satellite cell; Skeletal muscle