ERK1 and ERK2 are required for radial glial maintenance and cortical lamination |
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Authors: | Osamu Imamura Gilles Pagès Jacques Pouysségur Shogo Endo Kunio Takishima |
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Affiliation: | 1. Department of Biochemistry, National Defense Medical College, 3‐2 Namiki, Tokorozawa 359‐8513, Japan;2. University of Nice Sophia Antipolis, Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543, Centre A. Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France;3. Unit for Molecular Neurobiology of Learning and Memory, Initial Research Project, Okinawa Institute of Science and Technology, Uruma 904‐2234, Japan |
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Abstract: | ERK1/2 is involved in a variety of cellular processes during development, but the functions of these isoforms in brain development remain to be determined. Here, we generated double knockout (DKO) mice to study the individual and combined roles of ERK1 and ERK2 during cortical development. Mice deficient in Erk2, and more dramatically in the DKOs, displayed proliferation defects in late radial glial progenitors within the ventricular zone, and a severe disruption of lamination in the cerebral cortex. Immunohistochemical analyses revealed that late‐generated cortical neurons were misplaced and failed to migrate the upper cortical layers in DKO mice. Moreover, these mice displayed fewer radial glial fibers, which provide architectural guides for radially migrating neurons. These results suggest that extracellular signal‐regulated kinase signaling is essential for the expansion of the radial glial population and for the maintenance of radial glial scaffolding. Tangential migration of interneurons and oligodendrocytes from the ganglionic eminences (GE) to the dorsal cortex was more severely impaired in DKO mice than in mice deficient for Erk2 alone, because of reduced progenitor proliferation in the GE of the ventral telencephalon. These data demonstrate functional overlaps between ERK1 and ERK2 and indicate that extracellular signal‐regulated kinase signaling plays a crucial role in cortical development. |
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