title: A complex containing the Sm protein CAR-1 and the RNA helicase CGH-1 is required for embryonic cytokinesis in Caenorhabditis elegans.
abstract: Cytokinesis completes cell division and partitions the contents of one cell to the two daughter cells. Here we characterize CAR-1, a predicted RNA binding protein that is implicated in cytokinesis. CAR-1 localizes to germline-specific RNA-containing particles and copurifies with the essential RNA helicase, CGH-1, in an RNA-dependent fashion. The atypical Sm domain of CAR-1, which directly binds RNA, is dispensable for CAR-1 localization, but is critical for its function. Inhibition of CAR-1 by RNA-mediated depletion or mutation results in a specific defect in embryonic cytokinesis. This cytokinesis failure likely results from an anaphase spindle defect in which interzonal microtubule bundles that recruit Aurora B kinase and the kinesin, ZEN-4, fail to form between the separating chromosomes. Depletion of CGH-1 results in sterility, but partially depleted worms produce embryos that exhibit the CAR-1-depletion phenotype. Cumulatively, our results suggest that CAR-1 functions with CGH-1 to regulate a specific set of maternally loaded RNAs that is required for anaphase spindle structure and cytokinesis.
authors.affiliation: Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA. aaudhya@ucsd.edu
authors.forename: Anjon
authors.initials: A
authors.lastname: Audhya
authors.forename: Francie
authors.initials: F
authors.lastname: Hyndman
authors.forename: Ian X
authors.initials: IX
authors.lastname: McLeod
authors.forename: Amy S
authors.initials: AS
authors.lastname: Maddox
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Arshad
authors.initials: A
authors.lastname: Desai
authors.forename: Karen
authors.initials: K
authors.lastname: Oegema
mesh_terms: D000705:Anaphase / Q000502:physiology; D000818:Animals; D064107:Aurora Kinase B; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology*; D016547:Kinesins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034622:RNA Interference / Q000502:physiology; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000737:chemistry / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; C506963:Car-1 protein, C elegans; D016601:RNA-Binding Proteins; C114455:ZEN-4 protein, C elegans; D064107:Aurora Kinase B; D017346:Protein Serine-Threonine Kinases; C491506:air-2 protein, C elegans; D012316:RNA Nucleotidyltransferases; C490618:cgh-1 protein, C elegans; D016547:Kinesins