Poly(ADP-ribose) is required for spindle assembly and structure.
The mitotic spindle is typically thought of as an array of microtubules, microtubule-associated proteins and motors that self-organizes to align and segregate chromosomes. The major spindle components consist of proteins and DNA, the primary structural elements of the spindle. Other macromolecules including RNA and lipids also associate with spindles, but their spindle function, if any, is unknown. Poly(ADP-ribose) (PAR) is a large, branched, negatively charged polymeric macromolecule whose polymerization onto acceptor proteins is catalysed by a family of poly(ADP-ribose) polymerases (PARPs). Several PARPs localize to the spindle in vertebrate cells, suggesting that PARPs and/or PAR have a role in spindle function. Here we show that PAR is enriched in the spindle and is required for spindle function--PAR hydrolysis or perturbation leads to rapid disruption of spindle structure, and hydrolysis during spindle assembly blocks the formation of bipolar spindles. PAR exhibits localization dynamics that differ from known spindle proteins and are consistent with a low rate of turnover in the spindle. Thus, PAR is a non-proteinaceous, non-chromosomal component of the spindle required for bipolar spindle assembly and function.
Chang
Paul
P
Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA. paul_chang2@hms.harvard.edu
Jacobson
Myron K
MK
Mitchison
Timothy J
TJ
D000818:Animals; D002417:Cattle; D003593:Cytoplasm / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D016547:Kinesins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D008941:Spindle Apparatus / Q000737:chemistry* / Q000378:metabolism*; D029867:Xenopus Proteins / Q000378:metabolism; D014982:Xenopus laevis / Q000378:metabolism
C088335:KIF11 protein, Xenopus; C489079:NUMA1 protein, Xenopus; D009687:Nuclear Proteins; D029867:Xenopus Proteins; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase; D016547:Kinesins