Regulation of otocyst patterning by <i>Tbx2</i> and <i>Tbx3</i> is required for inner ear morphogenesis in the mouse

ABSTRACT All epithelial components of the inner ear, including sensory hair cells and innervating afferent neurons, arise by patterning differentiation progenitors residing in a simple sphere, otocyst. Here, we identify transcriptional repressors TBX2 TBX3 as novel regulators these processes mouse. Ablation Tbx2 from otocyst led to cochlear hypoplasia, whereas loss Tbx3 was associated with vestibular malformations. The function both genes (Tbx2/3cDKO) prevented ear morphogenesis at midgestation, resulting indiscernible structures birth. Morphogenetic impairment occurred concomitantly increased apoptosis ventral lateral regions Tbx2/3cDKO otocysts around E10.5. Expression analyses revealed partly disturbed regionalisation, posterior-ventral expansion neurogenic domain this stage. We provide evidence that repression FGF signalling is important restrict neurogenesis anterior-ventral implicate another T-box factor, TBX1, crucial mediator regulatory network.