title: Retinoic acid alters photoreceptor development in vivo.
abstract: Application of exogenous retinoic acid (RA) to zebrafish during the initial stages of photoreceptor differentiation results in a precocious development of rod photoreceptors and an inhibition of cone photoreceptor maturation. The acceleration of rod differentiation is observed initially within the ventral retina 3 days after fertilization, following 24 hr of RA application, and within the dorsal retina 4 days after fertilization, following 48 hr of RA application. The differentiation of rods was impeded significantly when the synthesis of endogenous retinoic acid was inhibited by citral prior to the initial stage of rod differentiation. RA-treated embryos labeled for bromodeoxyuridine (BrdU) uptake revealed that RA exerts its effect on a postmitotic cell population within the developing retina. During normal development in zebrafish, rod differentiation is most robust within the ventral retina, a region previously shown to be rich in RA. Our data suggest that the RA signaling pathway is involved in the differentiation and maturation of both the rod and cone photoreceptors within the developing zebrafish retina.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Hyatt
authors.forename: E A
authors.initials: EA
authors.lastname: Schmitt
authors.forename: J M
authors.initials: JM
authors.lastname: Fadool
authors.forename: J E
authors.initials: JE
authors.lastname: Dowling
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004625:Embryo, Nonmammalian; D007150:Immunohistochemistry; D010786:Photoreceptor Cells / Q000187:drug effects / Q000196:embryology*; D012016:Reference Values; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D017299:Rod Opsins / Q000096:biosynthesis*; D014158:Transcription, Genetic / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*; D015027:Zebrafish
chemical_list: D017299:Rod Opsins; D014212:Tretinoin