title: Lfc and Tctex-1 regulate the genesis of neurons from cortical precursor cells.
abstract: The mechanisms that regulate symmetric, proliferative divisions versus asymmetric, neurogenic divisions of mammalian neural precursors are still not well understood. We found that Lfc (Arhgef2), a Rho-specific guanine nucleotide exchange factor that interacts with spindle microtubules, and its negative regulator Tctex-1 (Dynlt1) determine the genesis of neurons from precursors in the embryonic murine cortex. Specifically, genetic knockdown of Arhgef2 in cortical precursors either in culture or in vivo inhibited neurogenesis and maintained cells as cycling radial precursors. Conversely, genetic knockdown of Dynlt1 in radial precursors promoted neurogenesis and depleted cycling cortical precursors. Coincident silencing of these two genes indicated that Tctex-1 normally inhibits the genesis of neurons from radial precursors by antagonizing the proneurogenic actions of Lfc. Moreover, Lfc and Tctex-1 were required to determine the orientation of mitotic precursor cell divisions in vivo. Thus, Lfc and Tctex-1 interact to regulate cortical neurogenesis, potentially by regulating mitotic spindle orientation.
authors.affiliation: Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Andrée
authors.initials: A
authors.lastname: Gauthier-Fisher
authors.forename: Dan C
authors.initials: DC
authors.lastname: Lin
authors.forename: Melissa
authors.initials: M
authors.lastname: Greeve
authors.forename: David R
authors.initials: DR
authors.lastname: Kaplan
authors.forename: Robert
authors.initials: R
authors.lastname: Rottapel
authors.forename: Freda D
authors.initials: FD
authors.lastname: Miller
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D016764:Cell Polarity / Q000235:genetics; D049109:Cell Proliferation; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology*; D015536:Down-Regulation / Q000235:genetics; D004398:Dyneins; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008938:Mitosis / Q000235:genetics; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D064067:Rho Guanine Nucleotide Exchange Factors; D015398:Signal Transduction / Q000235:genetics; D008941:Spindle Apparatus / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics; D056427:t-Complex Genome Region
chemical_list: C577402:Arhgef2 protein, mouse; D018797:Cell Cycle Proteins; C533386:Dynlt1b protein, mouse; D020662:Guanine Nucleotide Exchange Factors; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; D004398:Dyneins; D020742:rhoA GTP-Binding Protein