Expression patterns of Irx genes in the developing

Authors: Sheila CardeñaNúñez Luis Óscar SánchezGuardado Rubén CorralSanMiguel Lucía RodríguezGallardo Faustino Marín Luis Puelles Pilar Aroca Matías HidalgoSánchez

Publish Date: 2016/10/25

Volume: 222, Issue: 5, Pages: 2071-2092

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Abstract

The vertebrate inner ear is a complex threedimensional sensorial structure with auditory and vestibular functions The molecular patterning of the developing otic epithelium creates various positional identities consequently leading to the stereotyped specification of each neurosensory and nonsensory element of the membranous labyrinth The Iroquois Iro/Irx genes clustered in two groups A Irx1 Irx2 and Irx4 and B Irx3 Irx5 and Irx6 encode for transcriptional factors involved directly in numerous patterning processes of embryonic tissues in many phyla This work presents a detailed study of the expression patterns of these six Irx genes during chick inner ear development paying particular attention to the axial specification of the otic anlagen The Irx genes seem to play different roles at different embryonic periods At the otic vesicle stage HH18 all the genes of each cluster are expressed identically Both clusters A and B seem involved in the specification of the lateral and posterior portions of the otic anlagen Cluster B seems to regulate a larger area than cluster A including the presumptive territory of the endolymphatic apparatus Both clusters seem also to be involved in neurogenic events At stages HH24/25HH27 combinations of IrxA and IrxB genes participate in the specification of most sensory patches and some nonsensory components of the otic epithelium At stage HH34 the six Irx genes show divergent patterns of expression leading to the final specification of the membranous labyrinth as well as to cell differentiation

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