title: The vertebrate-specific Kinesin-6, Kif20b, is required for normal cytokinesis of polarized cortical stem cells and cerebral cortex size.
abstract: Mammalian neuroepithelial stem cells divide using a polarized form of cytokinesis, which is not well understood. The cytokinetic furrow cleaves the cell by ingressing from basal to apical, forming the midbody at the apical membrane. The midbody mediates abscission by recruiting many factors, including the Kinesin-6 family member Kif20b. In developing embryos, Kif20b mRNA is most highly expressed in neural stem/progenitor cells. A loss-of-function mutant in Kif20b, magoo, was found in a forward genetic screen. magoo has a small cerebral cortex, with reduced production of progenitors and neurons, but preserved layering. In contrast to other microcephalic mouse mutants, mitosis and cleavage furrows of cortical stem cells appear normal in magoo. However, apical midbodies show changes in number, shape and positioning relative to the apical membrane. Interestingly, the disruption of abscission does not appear to result in binucleate cells, but in apoptosis. Thus, Kif20b is required for proper midbody organization and abscission in polarized cortical stem cells and has a crucial role in the regulation of cerebral cortex growth.
authors.affiliation: Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Kerstin M
authors.initials: KM
authors.lastname: Janisch
authors.forename: Vita M
authors.initials: VM
authors.lastname: Vock
authors.forename: Michael S
authors.initials: MS
authors.lastname: Fleming
authors.forename: Ayushma
authors.initials: A
authors.lastname: Shrestha
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Grimsley-Myers
authors.forename: Bareza A
authors.initials: BA
authors.lastname: Rasoul
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Neale
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Cupp
authors.forename: Jason M
authors.initials: JM
authors.lastname: Kinchen
authors.forename: Karel F
authors.initials: KF
authors.lastname: Liem
authors.forename: Noelle D
authors.initials: ND
authors.lastname: Dwyer
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000235:genetics; D002540:Cerebral Cortex / Q000378:metabolism*; D048749:Cytokinesis / Q000502:physiology*; D015870:Gene Expression; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008870:Microtubules / Q000378:metabolism; D058953:Neural Stem Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D012333:RNA, Messenger; C583649:KIF20B protein, mouse; D016547:Kinesins
keywords: Abscission; Cortical development; Cytokinesis; Kif20b; Kinesin-6; Microcephaly; Mouse; Neural stem cells