Hypaxial muscle migration during primary myogenesis in Xenopus laevis.
In contrast to many vertebrates, the ventral body wall muscles and limb muscles of Xenopus develop at different times. The ventral body wall forms in the tadpole, while limb (appendicular) muscles form during metamorphosis to the adult frog. In organisms that have been examined thus far, a conserved mechanism has been shown to control migratory muscle precursor specification, migration, and differentiation. Here, we show that the process of ventral body wall formation in Xenopus laevis is similar to hypaxial muscle development in chickens and mice. Cells specified for the migratory lineage display an upregulation of pax3 in the ventro-lateral region of the somite. These pax3-positive cells migrate ventrally, away from the somite, and undergo terminal differentiation with the expression of myf-5, followed by myoD. Several other genes are selectively expressed in the migrating muscle precursor population, including neural cell adhesion molecule (NCAM), Xenopus kit related kinase (Xkrk1), and Xenopus SRY box 5 (sox5). We have also found that muscle precursor migration is highly coordinated with the migration of neural crest-derived melanophores. However, by extirpating neural crest at an early stage and allowing embryos to develop, we determined that muscle precursor migration is not dependent on physical or genetic interaction with melanophores.
Martin
B L
BL
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202, USA.
Harland
R M
RM
D000818:Animals; D002448:Cell Adhesion; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology; D017403:In Situ Hybridization; D008547:Melanophores / Q000378:metabolism; D009132:Muscles / Q000166:cytology* / Q000196:embryology*; D019006:Neural Cell Adhesion Molecules / Q000502:physiology; D009432:Neural Crest / Q000196:embryology; D009687:Nuclear Proteins / Q000502:physiology; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis / Q000502:physiology; D055755:SOXD Transcription Factors; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins / Q000096:biosynthesis; D014982:Xenopus laevis
D004268:DNA-Binding Proteins; D019006:Neural Cell Adhesion Molecules; D009687:Nuclear Proteins; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; C489411:Pax3 protein, Xenopus; D055755:SOXD Transcription Factors; C490302:Sox5 protein, Xenopus; D014157:Transcription Factors; D029867:Xenopus Proteins; C068686:Pax3 protein, mouse; D019009:Proto-Oncogene Proteins c-kit; C444981:xkrk1 protein, Xenopus