Neurogenin3 promotes early retinal neurogenesis.
The transcriptional regulatory network governing the establishment of retinal neuron diversity is not well delineated. We report experimental results suggesting proneural gene neurogenin3 (ngn3) participating in this regulatory network. Retinal expression of chick ngn3 was confined to early neurogenesis. Overexpression of ngn3 in chick retina reduced cell proliferation and expanded the population of ganglion cells into the territory normally occupied by amacrine cells. Ngn3 overexpression altered the expression of a number of regulatory genes, including ash1, ath3, ath5, chx10, neuroD, ngn1, ngn2, and NSCL1. Early gene ngn1 was induced, but ash1, ngn2, ath3, and chx10, whose expressions persist through later phases of neurogenesis, were down-regulated. Expression of ath5 was up-regulated at the locale corresponding to young ganglion cells, but was down-regulated at the locale corresponding to progenitor cells. These results suggest that ngn3 regulates retinal neurogenesis by inducing regulatory genes for early-born neurons and repressing those for later-born cells.
Ma
Wenxin
W
Department of Ophthalmology, University of Alabama at Birmingham, 700 South 18th Street, Birmingham, AL 35233, USA.
Yan
Run-Tao
RT
Mao
Weiming
W
Wang
Shu-Zhen
SZ
D000595:Amino Acid Sequence; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002642:Chick Embryo; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D055495:Neurogenesis / Q000502:physiology*; D012160:Retina / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D055351:Retinal Neurons / Q000166:cytology / Q000502:physiology*; D016415:Sequence Alignment; D013234:Stem Cells / Q000166:cytology / Q000502:physiology
D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; C498695:NEUROG3 protein, human; C407737:Neurog3 protein, mouse