title: Extraocular ectoderm triggers dorsal retinal fate during optic vesicle evagination in zebrafish.
abstract: Dorsal retinal fate is established early in eye development, via expression of spatially restricted dorsal-specific transcription factors in the optic vesicle; yet the events leading to initiation of dorsal fate are not clear. We hypothesized that induction of dorsal fate would require an extraocular signal arising from a neighboring tissue to pattern the prospective dorsal retina, however no such signal has been identified. We used the zebrafish embryo to determine the source, timing, and identity of the dorsal retina-inducing signal. Extensive cell movements occur during zebrafish optic vesicle morphogenesis, however the location of prospective dorsal cells within the early optic vesicle and their spatial relationship to early dorsal markers is currently unknown. Our mRNA expression and fate mapping analyses demonstrate that the dorsolateral optic vesicle is the earliest region to express dorsal specific markers, and cells from this domain contribute to the dorsal retinal pole at 24 hpf. We show that three bmp genes marking dorsal retina at 25 hpf are also expressed extraocularly before retinal patterning begins. We identified gdf6a as a dorsal initiation signal acting from the extraocular non-neural ectoderm during optic vesicle evagination. We find that bmp2b is involved in dorsal retina initiation, acting upstream of gdf6a. Together, this work has identified the nature and source of extraocular signals required to pattern the dorsal retina.
authors.affiliation: Department of Neurobiology and Anatomy, 20 North 1900 East, Room 401 MREB, University of Utah, Salt Lake City, UT 84132, USA.
authors.forename: Renee
authors.initials: R
authors.lastname: Kruse-Bend
authors.forename: Jude
authors.initials: J
authors.lastname: Rosenthal
authors.forename: Tyler S
authors.initials: TS
authors.lastname: Quist
authors.forename: Eric S
authors.initials: ES
authors.lastname: Veien
authors.forename: Sabine
authors.initials: S
authors.lastname: Fuhrmann
authors.forename: Richard I
authors.initials: RI
authors.lastname: Dorsky
authors.forename: Chi-Bin
authors.initials: CB
authors.lastname: Chien
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D004475:Ectoderm / Q000378:metabolism / Q000502:physiology*; D005123:Eye / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D005838:Genotype; D055431:Growth Differentiation Factor 6 / Q000378:metabolism*; D017403:In Situ Hybridization; D009024:Morphogenesis / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011720:Pyrazoles; D011743:Pyrimidines; D012160:Retina / Q000166:cytology / Q000196:embryology*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D055396:Bone Morphogenetic Protein 2; D017931:DNA Primers; D055431:Growth Differentiation Factor 6; C554430:LDN 193189; D011720:Pyrazoles; D011743:Pyrimidines; D029961:Zebrafish Proteins; C405936:bmp2b protein, zebrafish; C420987:gdf6a protein, zebrafish