title: The developmental sequence of gene expression within the rod photoreceptor lineage in embryonic zebrafish.
abstract: In postembryonic zebrafish, rod photoreceptors are continuously generated from progenitors in the inner nuclear layer, which are derived from radial Müller glia that express the transcription factor pax6. We used BrdU incorporation, in combination with in situ hybridization for cell-specific transcription factors, to establish the patterns of gene expression during rod lineage maturation in the embryonic zebrafish. Downregulation of pax6 expression was accompanied by sporadic upregulation of expression of the transcription factors NeuroD/nrd, rx1, crx, and Nr2e3/pnr. As cells of the rod lineage entered the outer nuclear layer, they became homogeneous, coordinately expressing NeuroD, rx1, crx, and Nr2e3. Postmitotic, maturing rods also expressed nrl, rod opsin, and rod transducin/gnat1. The presence of rx1 within the rod lineage and in maturing rods indicates that rx1 is not cone-specific, as previously reported, and suggests a high degree of molecular similarity between rod and cone progenitor populations in the zebrafish.
authors.affiliation: Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844-3051, USA.
authors.forename: Steve M
authors.initials: SM
authors.lastname: Nelson
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Frey
authors.forename: Sheri L
authors.initials: SL
authors.lastname: Wardwell
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Stenkamp
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D015415:Biomarkers; D001973:Bromodeoxyuridine; D019070:Cell Lineage; D049109:Cell Proliferation; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D017948:Retinal Rod Photoreceptor Cells / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018398:Homeodomain Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C464524:rx1 protein, zebrafish; D001973:Bromodeoxyuridine