Sox2 and Fgf interact with Atoh1 to promote sensory competence throughout the zebrafish inner ear

► Misexpression of zebrafish Atoh1a promotes sensory development in the otic vesicle. ► Responsiveness to Atoh1a is spatially restricted at all stages and declines with age. ► Misexpression of Sox2 or Fgf3/8 greatly expands the zone of responsiveness to Atoh1a. ► Sox2 enhances prosensory activity of Atoh1a even at relatively late stages. ► Atoh1a acts in a gene network with Fgf and Sox2 to promote sensory development.