title: FGF19-FGFR4 signaling elaborates lens induction with the FGF8-L-Maf cascade in the chick embryo.
abstract: The fibroblast growth factor (FGF) family is known to be involved in vertebrate eye development. However, distinct roles of individual FGF members during eye development remain largely elusive. Here, we show a detailed expression pattern of Fgf19 in chick lens development. Fgf19 expression initiated in the forebrain, and then became restricted to the distal portion of the optic vesicle abutting the future lens placode, where FGF receptor 4 (Fgfr4), a receptor for FGF19, was expressed. Fgf8, a positive regulator for L-Maf, was expressed in a portion of the optic vesicle. To examine the role of FGF19 signaling during early eye development, Fgf19 was misexpressed near the presumptive lens ectoderm; however, no alteration in the expression of lens marker genes was observed. Conversely, a secreted form of FGFR4 was misexpressed to inhibit an FGF19 signal, resulting in the induction of L-Maf expression. To further define the relationship between L-Maf and Fgf19, L-Maf misexpression was performed, resulting in ectopic induction of Fgf19 expression by Hamburger and Hamilton's stage 12/13. Furthermore, misexpression of Fgf8 induced Fgf19 expression in addition to L-Maf. These results suggest that FGF19-FGFR4 signaling plays a role in early lens development in collaboration with FGF8 signaling and L-Maf transcriptional system.
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, University of Tokushima, 2-1 Minami-Jyosanjima, Tokushima 770-8506, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Kurose
authors.forename: Mayumi
authors.initials: M
authors.lastname: Okamoto
authors.forename: Miyuki
authors.initials: M
authors.lastname: Shimizu
authors.forename: Takaaki
authors.initials: T
authors.lastname: Bito
authors.forename: Cristophe
authors.initials: C
authors.lastname: Marcelle
authors.forename: Sumihare
authors.initials: S
authors.lastname: Noji
authors.forename: Hideyo
authors.initials: H
authors.lastname: Ohuchi
mesh_terms: D000818:Animals; D002642:Chick Embryo; D004475:Ectoderm / Q000276:immunology; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors / Q000032:analysis / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D015870:Gene Expression; D005819:Genetic Markers; D007908:Lens, Crystalline / Q000196:embryology* / Q000276:immunology / Q000378:metabolism; D050977:Maf Transcription Factors; D051499:Receptor, Fibroblast Growth Factor, Type 4; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D005819:Genetic Markers; C111440:L-MAF protein, Gallus gallus; D050977:Maf Transcription Factors; D017468:Receptors, Fibroblast Growth Factor; D014157:Transcription Factors; D051524:Fibroblast Growth Factor 8; D005346:Fibroblast Growth Factors; D051499:Receptor, Fibroblast Growth Factor, Type 4