title: The orientation of cell division influences cell-fate choice in the developing mammalian retina.
abstract: Asymmetric segregation of cell-fate determinants during cell division plays an important part in generating cell diversity in invertebrates. We showed previously that cells in the neonatal rat retina divide at various orientations and that some dividing cells asymmetrically distribute the cell-fate determinant Numb to the two daughter cells. Here, we test the possibility that such asymmetric divisions contribute to retinal cell diversification. We have used long-term videomicroscopy of green-fluorescent-protein (GFP)-labeled retinal explants from neonatal rats to visualize the plane of cell division and follow the differentiation of the daughter cells. We found that cells that divided with a horizontal mitotic spindle, where both daughter cells should inherit Numb, tended to produce daughters that became the same cell type, whereas cells that divided with a vertical mitotic spindle, where only one daughter cell should inherit Numb, tended to produce daughters that became different. Moreover, overexpression of Numb in the dividing cells promoted the development of photoreceptor cells at the expense of interneurons and Müller glial cells. These findings indicate that the plane of cell division influences cell-fate choice in the neonatal rat retina and support the hypothesis that the asymmetric segregation of Numb normally influences some of these choices.
authors.affiliation: MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London WC1E 6BT, UK. m.cayouette@stanford.edu
authors.forename: Michel
authors.initials: M
authors.lastname: Cayouette
authors.forename: Martin
authors.initials: M
authors.lastname: Raff
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D002455:Cell Division; D046508:Culture Techniques; D005136:Eye Proteins / Q000235:genetics; D049452:Green Fluorescent Proteins; D007395:Interneurons / Q000166:cytology; D008164:Luminescent Proteins / Q000235:genetics; D018715:Microscopy, Video; D008938:Mitosis; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000235:genetics; D020419:Photoreceptor Cells, Vertebrate / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000235:genetics; D012160:Retina / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins