Control of planar divisions by the G-protein regulator LGN maintains progenitors in the chick neuroepithelium.
The spatio-temporal regulation of symmetrical as opposed to asymmetric cell divisions directs the fate and location of cells in the developing CNS. In invertebrates, G-protein regulators control spindle orientation in asymmetric divisions, which generate progeny with different identities. We investigated the role of the G-protein regulator LGN (also called Gpsm2) in spindle orientation and cell-fate determination in the spinal cord neuroepithelium of the developing chick embryo. We show that LGN is located at the cell cortex and spindle poles of neural progenitors, and that it regulates spindle movements and orientation. LGN promotes planar divisions in the early spinal cord. Interfering with LGN function randomizes the plane of division. Notably, this does not affect cell fate, but frequently leads one daughter of proliferative symmetric divisions to exit the neuroepithelium prematurely and to proliferate aberrantly in the mantle zone. Hence, tight control of planar spindle orientation maintains neural progenitors in the neuroepithelium, and regulates the proper development of the nervous system.
Morin
Xavier
X
Institute of Developmental Biology of Marseille-Luminy, Centre National de la Recherche Scientifique UMR 6216, Case 907, Campus de Luminy, 13288 Marseille Cedex9, France. morin@ibdml.univ-mrs.fr
Jaouen
Florence
F
Durbec
Pascale
P
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D049109:Cell Proliferation; D002642:Chick Embryo; D003001:Cloning, Molecular / Q000379:methods; D003598:Cytoskeletal Proteins / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000378:metabolism; D046569:Neuroepithelial Cells / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology; D013234:Stem Cells / Q000502:physiology*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; C502655:LGN protein, mouse; D009419:Nerve Tissue Proteins; D049452:Green Fluorescent Proteins