A complex containing the Sm protein CAR-1 and the RNA helicase CGH-1 is required for embryonic cytokinesis in Caenorhabditis elegans.
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.
Audhya
Anjon
A
Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA. aaudhya@ucsd.edu
Hyndman
Francie
F
McLeod
Ian X
IX
Maddox
Amy S
AS
Yates
John R
JR
Desai
Arshad
A
Oegema
Karen
K
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
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