Abstract
The transcription factors required to initiate myogenesis in branchial arch- and somite-derived muscles are known, but the comparable upstream factors required during extraocular muscle development have not been identified. We show Pax7 is dispensable for extraocular muscle formation, whereas Pitx2 is cell-autonomously required to prevent apoptosis of the extraocular muscle primordia. The survival requirement for Pitx2 is stage-dependent and ends following stable activation of genes for the muscle regulatory factors (e.g. Myf5, MyoD), which is reduced in the absence of Pitx2. Further, PITX2 binds and activates transcription of the Myf5 and MyoD promoters, indicating these genes are direct targets. Collectively, these data demonstrate that PITX2 is required at several steps in the development of extraocular muscles, acting first as an anti-apoptotic factor in pre-myogenic mesoderm, and subsequently to activate the myogenic program in these cells. Thus, Pitx2 is the first demonstrated upstream activator of myogenesis in the extraocular muscles.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.