title: Expression patterns of Irx genes in the developing chick inner ear.
abstract: The vertebrate inner ear is a complex three-dimensional 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 non-sensory 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 HH24/25-HH27, combinations of IrxA and IrxB genes participate in the specification of most sensory patches and some non-sensory 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.
authors: Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain.
authors: Sheila
authors: S
authors: Cardeña-Núñez
authors: Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain.
authors: Luis Óscar
authors: LÓ
authors: Sánchez-Guardado
authors: Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain.
authors: Rubén
authors: R
authors: Corral-San-Miguel
authors: Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain.
authors: Lucía
authors: L
authors: Rodríguez-Gallardo
authors: Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain.
authors: Faustino
authors: F
authors: Marín
authors: Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain.
authors: Luis
authors: L
authors: Puelles
authors: Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia and Instituto Murciano de Investigación Biosanitaria-Virgen de La Arrixaca (IMIB-Arrixaca), E30100, Murcia, Spain.
authors: Pilar
authors: P
authors: Aroca
authors: Department of Cell Biology, School of Science, University of Extremadura, Avda de Elvas s/n, E06071, Badajoz, Spain. mhidalgo@unex.es.
authors: Matías
authors: http://orcid.org/0000-0001-8573-8829
authors: M
authors: Hidalgo-Sánchez
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002642:Chick Embryo; D002645:Chickens; D007758:Ear, Inner / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014714:Vertebrates / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors
keywords: Acoustic-vestibular ganglion; Otic specification; Otic vesicle; Otocyst; Sensory patch