Delta-1 is a regulator of neurogenesis in the vertebrate retina.
In the retina, cell fate determination is thought to be regulated by a series of local cell-cell interactions. Evidence suggests that retinal precursors utilize Notch-mediated intercellular signaling to regulate their fates. However, the identity of the endogenous ligand and its role in the Notch-signaling pathway is not well understood. We have identified C-Delta-1 as the putative endogenous ligand for Notch, in the developing chick retina. C-Delta-1 is coexpressed spatially and temporally with C-Notch-1 and their expression is associated with the temporal aspects of cell birth in the developing retina. This suggests that Delta-Notch signaling is utilized to maintain progenitors in an uncommitted state and that a subtle fluctuation in this signaling helps to sort out competent cells during successive cell-fate determination. We have tested the latter possibility in the specification of the ganglion cells. In early stages of retinal development when ganglion cells are the predominant cells born, decreasing C-Delta-1 expression with antisense oligonucleotides increases the proportion of RA4 antigen-expressing ganglion cells which are recruited predominantly in the periphery. Conversely, use of exogenous Drosophila Delta leads to a decrease in the RA4 antigen-expressing ganglion cells. Our results suggest that C-Delta-1 activation of the Notch pathway regulates the specification of retinal neurons in general and of ganglion cells in particular.
Ahmad
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Department of Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha 68198-6395, USA.
Dooley
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CM
Polk
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DL
D000818:Animals; D002642:Chick Embryo; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009024:Morphogenesis; D009420:Nervous System / Q000196:embryology*; D009474:Neurons; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D014157:Transcription Factors
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D051881:Receptor, Notch1; D011956:Receptors, Cell Surface; D014157:Transcription Factors; C064045:delta protein