Terminal cytokinesis events uncovered after an RNAi screen.
Much of our understanding of animal cell cytokinesis centers on the regulation of the equatorial acto-myosin contractile ring that drives the rapid ingression of a deep cleavage furrow. However, the central part of the mitotic spindle collapses to a dense structure that impedes the furrow and keeps the daughter cells connected via an intercellular bridge. Factors involved in the formation, maintenance, and resolution of this bridge are largely unknown. Using a library of 7,216 double-stranded RNAs (dsRNAs) representing the conserved genes of Drosophila, we performed an RNA interference (RNAi) screen for cytokinesis genes in Schneider's S2 cells. We identified both familiar and novel genes whose inactivation induced a multi-nucleate phenotype. Using live video microscopy, we show that three genes: anillin, citron-kinase (CG10522), and soluble N-ethylmaleimide sensitive factor (NSF) attachment protein (alpha-SNAP), are essential for the terminal (post-furrowing) events of cytokinesis. anillin RNAi caused gradual disruption of the intercellular bridge after furrowing; citron-kinase RNAi destabilized the bridge at a later stage; alpha-SNAP RNAi caused sister cells to fuse many hours later and by a different mechanism. We have shown that the stability of the intercellular bridge is essential for successful cytokinesis and have defined genes contributing to this stability.
Echard
Arnaud
A
Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143-2200, USA.
Hickson
Gilles R X
GR
Foley
Edan
E
O'Farrell
Patrick H
PH
D000199:Actins / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D003285:Contractile Proteins / Q000235:genetics / Q000502:physiology; D048749:Cytokinesis / Q000502:physiology*; D004330:Drosophila; D015723:Gene Library; D047908:Intracellular Signaling Peptides and Proteins; D018715:Microscopy, Video; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D008941:Spindle Apparatus / Q000502:physiology*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000502:physiology
D000199:Actins; D003285:Contractile Proteins; D047908:Intracellular Signaling Peptides and Proteins; D012330:RNA, Double-Stranded; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D033921:Vesicular Transport Proteins; C095886:anillin; C115635:citron-kinase; D017346:Protein Serine-Threonine Kinases