Sox2 interacts with Atoh1 and Huwe1 loci to regulate Atoh1 transcription and stability during hair cell differentiation

Stem cell pluripotency gene Sox2 stimulates expression of proneural basic-helix-loop-helix transcription factor Atoh1. Sox2 is necessary for the development of cochlear hair cells and binds to the Atoh1 3’ enhancer to stimulate Atoh1 expression. We show here that Sox2 deletion in late embryogenesis results in the formation of extra hair cells, in contrast to the absence of hair cell development obtained after Sox2 knockout early in gestation. Sox2 overexpression decreased the level of Atoh1 protein despite an increase in Atoh1 mRNA. Sox2 upregulated E3 ubiquitin ligase, Huwe1, by direct binding to the Huwe1 gene. By upregulating its cognate E3 ligase, Sox2 disrupts the positive feedback loop through which Atoh1 protein increases the expression of Atoh1. We conclude that Sox2 initiates expression, while also limiting continued activity of bHLH transcription factor, Atoh1, and this inhibition represents a new mechanism for regulating the activity of this powerful initiator of hair cell de..., , , # Sox2 Interacts with Atoh1 and Huwe1 Loci to Regulate Atoh1 Transcription and Stability During Hair Cell Differentiation

[https://doi.org/10.5061/dryad.70rxwdc79](https://doi.org/10.5061/dryad.70rxwdc79)

## Description of the data and file structure

Regeneration of hair cells, the sensory cells of the cochlea, is a potential treatment for deafness. Here, we studied the regulation of *Atoh1*, a transcription factor required for the development of hair cells in the embryo. We discovered a dual role for Sox2 in determining the level of *Atoh1 expression in the cochlea. Sox2* initiates the expression of *Atoh1*, while also imposing a limit on the level of Atoh1 protein through concurrent activation of the proteasome pathway. This mechanism of *Atoh1* regulation explains the variable phenotypes induced by *Sox2* deletion: a lack of hair cells when *Sox2* was deleted early in embryogenesis was attributed to the missing stimulation by *Sox2* of *Atoh1* expression, while Sox2 deletion at la...