DOI: 10.5061/dryad.70rxwdc79
title: Sox2 interacts with Atoh1 and Huwe1 loci to regulate Atoh1 transcription and stability during hair cell differentiation

description: 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
 development.
description: # 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 later times in development resulted in an overproduction of hair cells due to decreased degradation of Atoh1 at the lowered level of E3 ubiquitin ligase *Huwe1 ( HECT domain E3 ubiquitin ligase)*. This seemingly contradictory signaling enables *Sox2* to direct the fate of inner ear progenitor cells through a brief burst of *Atoh1* gene expression followed immediately by degradation of the protein. DOX- Doxycycline, MG132- Proteosome inhibitor. ### Files and variables #### File: Values\_supporting\_each\_graph\_PLOS\_genetics.xlsx **Description:** Numerical values of all points in figures  ##### Variables * Figure 1D: Cell number * Figure 2A: Relative mRNA expression * Figure 2C: Relative mRNA expression * Figure 2F: Cell number * Figure 2I: Cell number * Figure 3B: Relative mRNA expression * Figure 3H: Cell number * Figure 3I: Cell number * Figure 4B: Fold enrichment * Figure 4D: Fold enrichment * Figure 5A: Relative mRNA expression * Figure 5E: Relative mRNA expression * Figure 5F: Relative mRNA expression * Figure 1S: Relative mRNA expression