%0 Journal Article
%T An Integrin-Dependent Role of Pouch Endoderm in Hyoid Cartilage Development
%A Justin Gage Crump
%A Mary E Swartz
%A Charles B Kimmel
%J PLOS Biology
%D 2004
%I Public Library of Science (PLoS)
%R 10.1371/journal.pbio.0020244
%X Pharyngeal endoderm is essential for and can reprogram development of the head skeleton. Here we investigate the roles of specific endodermal structures in regulating craniofacial development. We have isolated an integrin¦Á5 mutant in zebrafish that has region-specific losses of facial cartilages derived from hyoid neural crest cells. In addition, the cranial muscles that normally attach to the affected cartilage region and their associated nerve are secondarily reduced in integrin¦Á5£¿ animals. Earlier in development, integrin¦Á5 mutants also have specific defects in the formation of the first pouch, an outpocketing of the pharyngeal endoderm. By fate mapping, we show that the cartilage regions that are lost in integrin¦Á5 mutants develop from neural crest cells directly adjacent to the first pouch in wild-type animals. Furthermore, we demonstrate that Integrin¦Á5 functions in the endoderm to control pouch formation and cartilage development. Time-lapse recordings suggest that the first pouch promotes region-specific cartilage development by regulating the local compaction and survival of skeletogenic neural crest cells. Thus, our results reveal a hierarchy of tissue interactions, at the top of which is the first endodermal pouch, which locally coordinates the development of multiple tissues in a specific region of the vertebrate face. Lastly, we discuss the implications of a mosaic assembly of the facial skeleton for the evolution of ray-finned fish.
%U http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0020244