title: Doublecortin-like, a microtubule-associated protein expressed in radial glia, is crucial for neuronal precursor division and radial process stability.
abstract: During corticogenesis, progenitors divide within the ventricular zone where they rely on radial process extensions, formed by radial glial cell (RG) scaffolds, along which they migrate to the proper layers of the cerebral cortex. Although the microtubule-associated proteins doublecortin (DCX) and doublecortin-like kinase (DCLK) are critically involved in dynamic rearrangement of the cytoskeletal machinery that allow migration, little is known about their role in early corticogenesis. Here we have functionally characterized a mouse splice-variant of DCLK, doublecortin-like (DCL), exhibiting 73% amino acid sequence identity with DCX over its entire length. Unlike DCX, DCL is expressed from embryonic day 8 onwards throughout the early neuroepithelium. It is localized in mitotic cells, RGs and radial processes. DCL knockdown using siRNA in vitro induces spindle collapse in dividing neuroblastoma cells, whereas overexpression results in elongated and asymmetrical mitotic spindles. In vivo knockdown of the DCLK gene by in utero electroporation significantly reduced cell numbers in the inner proliferative zones and dramatically disrupted most radial processes. Our data emphasize the unique role of the DCLK gene in mitotic spindle integrity during early neurogenesis. In addition, they indicate crucial involvement of DCLK in RG proliferation and their radial process stability, a finding that has thus far not been attributed to DCX or DCLK.
authors.affiliation: Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, PO Box 9502, 2300 RA Leiden, The Netherlands. vreugden@lacdr.leidenuniv.nl
authors.forename: Erno
authors.initials: E
authors.lastname: Vreugdenhil
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Kolk
authors.forename: Karin
authors.initials: K
authors.lastname: Boekhoorn
authors.forename: Carlos P
authors.initials: CP
authors.lastname: Fitzsimons
authors.forename: Marcel
authors.initials: M
authors.lastname: Schaaf
authors.forename: Theo
authors.initials: T
authors.lastname: Schouten
authors.forename: Angela
authors.initials: A
authors.lastname: Sarabdjitsingh
authors.forename: Rosana
authors.initials: R
authors.lastname: Sibug
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lucassen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D003001:Cloning, Molecular; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D000089742:Doublecortin-Like Kinases; D005260:Female; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics; D008870:Microtubules / Q000502:physiology; D008969:Molecular Sequence Data; D019579:Neocortex / Q000166:cytology / Q000196:embryology* / Q000502:physiology; D009457:Neuroglia / Q000502:physiology*; D009474:Neurons / Q000166:cytology; D009479:Neuropeptides / Q000235:genetics; D011247:Pregnancy; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D034741:RNA, Small Interfering; D008941:Spindle Apparatus / Q000502:physiology; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology
chemical_list: C000714847:Dcx protein, mouse; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D034741:RNA, Small Interfering; D000089742:Doublecortin-Like Kinases; C485525:Dclk1 protein, mouse; D017346:Protein Serine-Threonine Kinases