Tankyrase-1 polymerization of poly(ADP-ribose) is required for spindle structure and function.
Poly(ADP-ribose) (PAR) is a large, negatively charged post-translational modification that is produced by polymerization of NAD+ by PAR polymerases (PARPs). There are at least 18 PARPs in the human genome, several of which have functions that are unknown. PAR modifications are dynamic; PAR structure depends on the balance between synthesis and hydrolysis by PAR glycohydrolase2. We previously found that PAR is enriched in vertebrate somatic-cell mitotic spindles and demonstrated a requirement for PAR in the assembly of Xenopus egg extract spindles. Here, we knockdown all characterized PARPs using RNA interference (RNAi), and identify tankyrase-1 as the PARP that is required for mitosis. Tankyrase-1 localizes to mitotic spindle poles, to telomeres and to the Golgi apparatus. Tankyrase-1 RNAi was recently shown to result in mitotic arrest, with abnormal chromosome distributions and spindle morphology observed--data that is interpreted as evidence of post-anaphase arrest induced by failure of telomere separation6. We show that tankyrase-1 RNAi results in pre-anaphase arrest, with intact sister-chromatid cohesion. We also demonstrate a requirement for tankyrase-1 in the assembly of bipolar spindles, and identify the spindle-pole protein NuMA as a substrate for covalent modification by tankyrase-1.
Chang
Paul
P
Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA. paul_chang2@hms.harvard.edu
Coughlin
Margaret
M
Mitchison
Timothy J
TJ
D000705:Anaphase; D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins / Q000378:metabolism; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D034622:RNA Interference; D008941:Spindle Apparatus / Q000201:enzymology / Q000502:physiology*; D038501:Tankyrases / Q000502:physiology*
D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D011064:Poly Adenosine Diphosphate Ribose; D038501:Tankyrases; C050045:NUMA1 protein, human; C418109:TNKS protein, human