Cranial muscle defects of Pitx2 mutants result from specification defects in the first branchial arch
- 3 April 2007
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 104 (14), 5907-5912
- https://doi.org/10.1073/pnas.0701122104
Abstract
Pitx2 expression is observed during all states of the myogenic progression in embryonic muscle anlagen and persists in adult muscle. Pitx2 mutant mice form all but a few muscle anlagen. Loss or degeneration in muscle anlagen could generally be attributed to the loss of a muscle attachment site induced by some other aspect of the Pitx2 phenotype. Muscles derived from the first branchial arch were absent, whereas muscles derived from the second branchial arch were merely distorted in Pitx2 mutants at midgestation. Pitx2 was expressed well before, and was required for, initiation of the myogenic progression in the first, but not second, branchial arch mesoderm. Pitx2 was also required for expression of premyoblast specification markers Tbx1, Tcf21, and Msc in the first, but not second, branchial arch. First, but not second, arch mesoderm of Pitx2 mutants failed to enlarge after embryonic day 9.5, well before the onset of the myogenic progression. Thus, Pitx2 contributes to specification of first, but not second, arch mesoderm. The jaw of Pitx2 mutants was vestigial by midgestation, but significant size reductions were observed as early as embryonic day 10.5. The diminutive first branchial arch of mutants could not be explained by loss of mesoderm alone, suggesting that Pitx2 contributes to the earliest specification of jaw itself.Keywords
This publication has 35 references indexed in Scilit:
- Tbx1 regulation of myogenic differentiation in the limb and cranial mesodermDevelopmental Dynamics, 2006
- Neural tube derived signals and Fgf8 act antagonistically to specify eye versus mandibular arch musclesDevelopment, 2006
- Nestin-Cre mediated deletion ofPitx2 in the mousegenesis, 2006
- Extraocular Muscle Morphogenesis and Gene Expression Are Regulated byPitx2Gene DoseInvestigative Ophthalmology & Visual Science, 2006
- Tbx1 affects asymmetric cardiac morphogenesis by regulatingPitx2in the secondary heart fieldDevelopment, 2006
- The differentiation and morphogenesis of craniofacial musclesDevelopmental Dynamics, 2006
- Fate Maps of Neural Crest and Mesoderm in the Mammalian EyeInvestigative Ophthalmology & Visual Science, 2005
- Expression of the homeobox gene Pitx2 in neural crest is required for optic stalk and ocular anterior segment developmentHuman Molecular Genetics, 2005
- Genetic dissection ofPitx2in craniofacial development uncovers new functions in branchial arch morphogenesis, late aspects of tooth morphogenesis and cell migrationDevelopment, 2003
- The role of the neural crest in patterning of avian cranial skeletal, connective, and muscle tissuesDevelopmental Biology, 1983