The role of Eya1 and Eya2 in the taste system of mice from embryonic stage to adulthood.

Members of the Eya family, which are a class of transcription factors with phosphatase activity, are widely expressed in cranial sensory organs during development. However, it is unclear whether these genes are expressed in the taste system during development and whether they play any role in specifying taste cell fate. In this study, we report that is not expressed during embryonic tongue development but that -expressing progenitors in somites or pharyngeal endoderm give rise to tongue musculature or taste organs, respectively. In the -deficient tongues, these progenitors do not proliferate properly, resulting in a smaller tongue at birth, impaired growth of taste papillae, and disrupted expression of in the papillary epithelium. On the other hand, is specifically expressed in endoderm-derived circumvallate and foliate papillae located on the posterior tongue during development. In adult tongues, is predominantly expressed in IPR3-positive taste cells in the taste buds of the circumvallate and foliate papillae, while is persistently expressed in these papillae at higher levels in some epithelial progenitors and at lower levels in some taste cells. We found that conditional knockout of in the third week or 2 knockout reduced Pou2f3, Six1 and IPR3 taste cells. Our data define for the first time the expression patterns of and during the development and maintenance of the mouse taste system and suggest that and may act together to promote lineage commitment of taste cell subtypes.