Histone demethylase KDM4B regulates otic vesicle invagination via epigenetic control of Dlx3 expression
In vertebrates, the inner ear arises from the otic placode, a thickened swathe of ectoderm that invaginates to form the otic vesicle. We report that histone demethylase KDM4B is dynamically expressed during early stages of chick inner ear formation. A loss of KDM4B results in defective invagination and striking morphological changes in the otic epithelium, characterized by abnormal localization of adhesion and cytoskeletal molecules and reduced expression of several inner ear markers, including Dlx3. In vivo chromatin immunoprecipitation reveals direct and dynamic occupancy of KDM4B and its target, H3K9me3, at regulatory regions of the Dlx3 locus. Accordingly, coelectroporations of DLX3 or KDM4B encoding constructs, but not a catalytically dead mutant of KDM4B, rescue the ear invagination phenotype caused by KDM4B knockdown. Moreover, a loss of DLX3 phenocopies a loss of KDM4B. Collectively, our findings suggest that KDM4B play a critical role during inner ear invagination via modulating histone methylation of the direct target Dlx3.
© 2015 Uribe et al. This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/). Submitted: 16 March 2015; Accepted: 15 October 2015. We thank Dr. M. Barembaum for pCIG-Dlx3 and pCIG-Dlx5 constructs and for insight throughout this study. This work was supported by grants from the Consejo Nacional de Investigaciones Científicas (CON ICET-PIP D4574) and Agencia Nacional de Promocion Cientifica y Tecnologica (PICT 2011-0500) to P.H. Strobl-Mazzulla and by the Consejo Nacional de Investigaciones Científicas-National Science Foundation grant (CON ICET-NSF D2445) to P.H. Strobl-Mazzulla, as well as by the following supplements from the National Institutes of Health: DC011577 to R.A. Uribe and DC011577 and DE16459 to M.E. Bronner. The authors declare no competing financial interests.
Published - J_Cell_Biol-2015-Uribe-815-27.pdf
Supplemental Material - JCB_201503071_sm.pdf