A conserved role for FGF signaling in chordate otic/atrial placode formation.

TitleA conserved role for FGF signaling in chordate otic/atrial placode formation.
Publication TypeJournal Article
Year of Publication2007
AuthorsKourakis MJ, Smith WC
JournalDev Biol
Volume312
Issue1
Pagination245-57
Date Published2007 Dec 1
ISSN1095-564X
KeywordsAnimals, Body Patterning, Butadienes, Chordata, Ear, Fibroblast Growth Factors, Gills, Laser Therapy, Mesoderm, Metamorphosis, Biological, Mitogen-Activated Protein Kinase Kinases, Nitriles, Protein Kinase Inhibitors, Receptors, Fibroblast Growth Factor, Sequence Homology, Amino Acid, Signal Transduction, Time Factors
Abstract

The widely held view that neurogenic placodes are vertebrate novelties has been challenged by morphological and molecular data from tunicates suggesting that placodes predate the vertebrate divergence. Here, we examine requirements for the development of the tunicate atrial siphon primordium, thought to share homology with the vertebrate otic placode. In vertebrates, FGF signaling is required for otic placode induction and for later events following placode invagination, including elaboration and patterning of the inner ear. We show that results from perturbation of the FGF pathway in the ascidian Ciona support a similar role for this pathway: inhibition with MEK or Fgfr inhibitor at tailbud stages in Ciona results in a larva which fails to form atrial placodes; inhibition during metamorphosis disrupts development of the atrial siphon and gill slits, structures which form where invaginated atrial siphon ectoderm apposes pharyngeal endoderm. We show that laser ablation of atrial primordium ectoderm also results in a failure to form gill slits in the underlying endoderm. Our data suggest interactions required for formation of the atrial siphon and highlight the role of atrial ectoderm during gill slit morphogenesis.

DOI10.1016/j.ydbio.2007.09.020
Alternate JournalDev. Biol.
PubMed ID17959164
PubMed Central IDPMC2169521
Grant ListGM075049 / GM / NIGMS NIH HHS / United States
HD038701 / HD / NICHD NIH HHS / United States
R01 HD038701-07 / HD / NICHD NIH HHS / United States
R24 GM075049-02 / GM / NIGMS NIH HHS / United States