title: Transcription factors involved in retinogenesis are co-opted by the circadian clock following photoreceptor differentiation.
abstract: The circadian clock is known to regulate a wide range of physiological and cellular processes, yet remarkably little is known about its role during embryo development. Zebrafish offer a unique opportunity to explore this issue, not only because a great deal is known about key developmental events in this species, but also because the clock starts on the very first day of development. In this study, we identified numerous rhythmic genes in zebrafish larvae, including the key transcriptional regulators neurod and cdx1b, which are involved in neuronal and intestinal differentiation, respectively. Rhythmic expression of neurod and several additional transcription factors was only observed in the developing retina. Surprisingly, these rhythms in expression commenced at a stage of development after these transcription factors are known to have played their essential role in photoreceptor differentiation. Furthermore, this circadian regulation was maintained in adult retina. Thus, once mature photoreceptors are formed, multiple retinal transcription factors fall under circadian clock control, at which point they appear to play a new and important role in regulating rhythmic elements in the phototransduction pathway.
authors.affiliation: Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London WC1E 6DE, UK.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Laranjeiro
authors.affiliation: Centre for Cell and Molecular Dynamics, Department of Cell and Developmental Biology, University College London, London WC1E 6DE, UK d.whitmore@ucl.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Whitmore
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D015153:Blotting, Western; D001973:Bromodeoxyuridine; D002454:Cell Differentiation / Q000502:physiology; D057906:Circadian Clocks / Q000502:physiology*; D017931:DNA Primers; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D009419:Nerve Tissue Proteins / Q000378:metabolism; D038081:Organogenesis / Q000502:physiology*; D010786:Photoreceptor Cells / Q000502:physiology*; D012160:Retina / Q000196:embryology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D001973:Bromodeoxyuridine; D017931:DNA Primers; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C529211:Cdx1b protein, zebrafish; C093564:Neurogenic differentiation factor 1
keywords: Circadian clock; Photoreceptors; Retina; Transcription factors; Zebrafish; neurod