title: Fgf3 and Fgf16 expression patterns define spatial and temporal domains in the developing chick inner ear.
abstract: The inner ear is a morphologically complex sensory structure with auditory and vestibular functions. The developing otic epithelium gives rise to neurosensory and non-sensory elements of the adult membranous labyrinth. Extrinsic and intrinsic signals manage the patterning and cell specification of the developing otic epithelium by establishing lineage-restricted compartments defined in turn by differential expression of regulatory genes. FGF3 and FGF16 are excellent candidates to govern these developmental events. Using the chick inner ear, we show that Fgf3 expression is present in the borders of all developing cristae. Strong Fgf16 expression was detected in a portion of the developing vertical and horizontal pouches, whereas the cristae show weaker or undetected Fgf16 expression at different developmental stages. Concerning the rest of the vestibular sensory elements, both the utricular and saccular maculae were Fgf3 positive. Interestingly, strong Fgf16 expression delimited these Fgf16-negative sensory patches. The Fgf3-negative macula neglecta and the Fgf3-positive macula lagena were included within weakly Fgf16-expressing areas. Therefore, different FGF-mediated mechanisms might regulate the specification of the anterior (utricular and saccular) and posterior (neglecta and lagena) maculae. In the developing cochlear duct, dynamic Fgf3 and Fgf16 expression suggests their cooperation in the early specification and later cell differentiation in the hearing system. The requirement of Fgf3 and Fgf16 genes in endolymphatic apparatus development and neurogenesis are discussed. Based on these observations, FGF3 and FGF16 seem to be key signaling pathways that control the inner ear plan by defining epithelial identities within the developing otic epithelium.
authors.affiliation: Department of Cell Biology, School of Science, University of Extremadura, Avda. de Elvas s/n, 06071, Badajoz, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Olaya-Sánchez
authors.affiliation: Department of Cell Biology, School of Science, University of Extremadura, Avda. de Elvas s/n, 06071, Badajoz, Spain.
authors.forename: Luis Óscar
authors.initials: LÓ
authors.lastname: Sánchez-Guardado
authors.affiliation: Department of Neurobiology and Anatomy, University of Utah, 2R066 School of Medicine, 30 N. 1900 E., Salt Lake City, UT, 84132-3401, USA.
authors.forename: Sho
authors.initials: S
authors.lastname: Ohta
authors.affiliation: Department of Biological Sciences, Clemson University, 340 Long Hall, Clemson, SC, 29634, USA.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Chapman
authors.affiliation: Department of Neurobiology and Anatomy, University of Utah, 2R066 School of Medicine, 30 N. 1900 E., Salt Lake City, UT, 84132-3401, USA.
authors.forename: Gary C
authors.initials: GC
authors.lastname: Schoenwolf
authors.affiliation: Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, 30100, Murcia, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Puelles
authors.affiliation: Department of Cell Biology, School of Science, University of Extremadura, Avda. de Elvas s/n, 06071, Badajoz, Spain. mhidalgo@unex.es.
authors.forename: Matías
authors.initials: M
authors.lastname: Hidalgo-Sánchez
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000378:metabolism*; D002645:Chickens; D007758:Ear, Inner / Q000196:embryology* / Q000378:metabolism*; D051518:Fibroblast Growth Factor 3 / Q000378:metabolism*; D005346:Fibroblast Growth Factors / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D051518:Fibroblast Growth Factor 3; D005346:Fibroblast Growth Factors
keywords: Acoustic-vestibular ganglion; Fibroblastic growth factors; Otic innervation; Otic specification; Sensory patches