PUBLICATION

The bHLH Transcription Factor NeuroD Governs Photoreceptor Genesis and Regeneration Through Delta-Notch Signaling

Authors
Taylor, S.M., Alvarez-Delfin, K., Saade, C.J., Thomas, J.L., Thummel, R., Fadool, J.M., Hitchcock, P.F.
ID
ZDB-PUB-151119-1
Date
2015
Source
Investigative ophthalmology & visual science   56: 7496-7515 (Journal)
Registered Authors
Hitchcock, Peter, Thomas, Jennifer, Thummel, Ryan
Keywords
none
MeSH Terms
  • Cell Differentiation
  • Animals, Genetically Modified
  • Photoreceptor Cells/cytology
  • Photoreceptor Cells/metabolism*
  • Nerve Tissue Proteins/biosynthesis
  • Nerve Tissue Proteins/genetics*
  • Gene Expression Regulation, Developmental*
  • Zebrafish/embryology*
  • Regeneration*
  • Cells, Cultured
  • Helix-Loop-Helix Motifs
  • RNA/genetics*
  • Receptors, Notch/metabolism*
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors/biosynthesis
  • Basic Helix-Loop-Helix Transcription Factors/genetics*
(all 16)
PubMed
26580854 Full text @ Invest. Ophthalmol. Vis. Sci.
Abstract
Photoreceptor genesis in the retina requires precise regulation of progenitor cell competence, cell cycle exit, and differentiation, although information around the mechanisms that govern these events currently is lacking. In zebrafish, the basic helix-loop-helix (bHLH) transcription factor NeuroD governs photoreceptor genesis, but the signaling pathways through which NeuroD functions are unknown. The purpose of this study was to identify these pathways, and during photoreceptor genesis, Notch signaling was investigated as the putative mediator of NeuroD function.
In embryos, genetic mosaic analysis was used to determine if NeuroD functions is cell- or non-cell-autonomous. Morpholino-induced NeuroD knockdown, CRISPR/Cas9 mutation, and pharmacologic and transgenic approaches were used, followed by in situ hybridization, immunocytochemistry, and quantitative RT-PCR (qRT-PCR), to identify mechanisms through which NeuroD functions. In adults, following photoreceptor ablation and NeuroD knockdown, similar methods as above were used to identify NeuroD function during photoreceptor regeneration.
In embryos, NeuroD function is non-cell-autonomous, NeuroD knockdown increases Notch pathway gene expression, Notch inhibition rescues the NeuroD knockdown-induced deficiency in cell cycle exit but not photoreceptor maturation, and Notch activation and CRISPR/Cas9 mutation of neurod recapitulate NeuroD knockdown. In adults, NeuroD knockdown prevents cell cycle exit and photoreceptor regeneration and increases Notch pathway gene expression, and Notch inhibition rescues this phenotype.
These data demonstrate that during embryonic development, NeuroD governs photoreceptor genesis via non-cell-autonomous mechanisms and that, during photoreceptor development and regeneration, Notch signaling is a mechanistic link between NeuroD and cell cycle exit. In contrast, during embryonic development, NeuroD governs photoreceptor maturation via mechanisms that are independent of Notch signaling.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Allele Construct Type Affected Genomic Region
b4
    Insertion
    fl1TgTransgenic Insertion
      kca3TgTransgenic Insertion
        mi2001TgTransgenic Insertion
          nl1TgTransgenic Insertion
            umk4TgTransgenic Insertion
              1 - 6 of 6
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              Human Disease / Model
              No data available
              Sequence Targeting Reagents
              Fish
              Antibodies
              Orthology
              Engineered Foreign Genes
              Marker Marker Type Name
              EGFPEFGEGFP
              GAL4FFEFGGAL4FF
              GFPEFGGFP
              1 - 3 of 3
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              Mapping