Signaling and morphogenesis during inner ear development

The inner ear begins its development as a plate of cells (the otic placode), formed from the surface ectoderm of the early embryo, and quickly invaginates to form the otocyst, the rudiment of the inner ear. Two aspects of inner ear development will be discussed: induction of the otic placode, and initial patterning of the otocyst to form the vestibular chamber. The former involves a cascade of growth factors including FGFs3, 4, and 19, and WNT8a, and the later involves BMPs acting through SMADs to regulate E‐cadherin expression and cell shape changes. As a result of such signaling, the ectoderm is transformed into the highly complex membranous labyrinth. Supported by grants from the National Institutes of Health and the Deafness Research Foundation..