Inner ear sensory organs, which mediate balance and hearing in mammals, and the VIIIth cranial ganglion neurons, which innervate them, are derived from the otocyst, an epithelial vesicle formed by invagination of the otic placode. Raft et al. now report that Tbx1 differentially controls sensory organ and neural fate specification in the otocyst (see ). Tbx1 is a member of the T-box family of DNA-binding transcriptional regulators that control diverse aspects of embryogenesis, including cell-fate specification,in many organisms. The researchers show that while overexpression of Tbx1 suppresses neurogenesis in the mouse otocyst epithelium, Tbx1 loss of function results in ectopic neural precursor generation and sensory organ dysmorphogenesis. Together with expression data, these results indicate that Tbx1 acts as a selector gene to specify regional identity in the otocyst.
