PT  - JOURNAL ARTICLE
AU  - Magdalena Żak
AU  - Vincent Plagnol
AU  - Nicolas Daudet
TI  - A gradient of Wnt activity positions the neurosensory domains of the inner ear
AID  - 10.1101/2020.05.04.071035
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.05.04.071035
4099  - http://biorxiv.org/content/early/2020/05/06/2020.05.04.071035.short
4100  - http://biorxiv.org/content/early/2020/05/06/2020.05.04.071035.full
AB  - The auditory and vestibular organs of the inner ear and the neurons that innervate them originate from Sox2-positive and Notch-active neurosensory domains specified at early stages of otic development. Sox2 is initially present throughout the otic placode and otocyst, then it becomes progressively restricted to a ventro-medial domain. Using gain and loss-of-function approaches in the chicken otocyst, we show that these early changes in Sox2 expression are regulated in a dose-dependent manner by Wnt/beta-catenin signalling. Both high and very low levels of Wnt activity repress Sox2 and neurosensory competence. However, intermediate levels allow the maintenance of Sox2 expression and sensory organ formation. We propose that a dorso-ventral (high-to-low) gradient and wave of Wnt activity initiated at the dorsal rim of the otic placode progressively restricts Sox2 and Notch activity to the ventral half of the otocyst, thereby positioning the neurosensory competent domains in the inner ear.Competing Interest StatementThe authors have declared no competing interest.