Abstract
CHO cells can be arrested with hydoxyurea at the beginning of the DNA synthesis phase of the cell cycle. Subsequent treatment with the xanthine, caffeine, induces cells to bypass the S-phase checkpoint and enter unscheduled mitosis [Schlegel and Pardee,1986, Science 232:1264-1266]. These treated cells build a normal spindle and distribute kinetochores, unattached to chromosomes, to their daughter cells [Brinkley et al.,1988, Nature 336:251-254; Zinkowski et al.,1991, J Cell Biol 113:1091-1110; Wise and Brinkley,1997, Cell Motil Cytoskeleton 36:291-302; Balczon et al.,2003, Chromosoma 112:96-102]. To investigate how these cells distribute kinetochores to daughter cells, we analyzed the spindle checkpoint components, Mad2, CENP-E, and the 3F3 phosphoepitope, using immunofluorescence and digital microscopy. Even though the kinetochores were unpaired and DNA was fragmented, the tension, alignment, and motor components of the checkpoint were found to be present and localized as predicted in prometaphase and metaphase. This unusual mitosis proves that a cell can successfully localize checkpoint proteins and divide even when kinetochores are unpaired and fragmented.
References
Aug 1, 1992·International Journal of Radiation Biology·T Jung, C Streffer
Jun 1, 1991·The Journal of Cell Biology·R P ZinkowskiB R Brinkley
Jun 6, 1986·Science·R Schlegel, A B Pardee
Nov 17, 1988·Nature·B R BrinkleyP N Rao
Sep 1, 1993·The Journal of Cell Biology·G J Gorbsky, W A Ricketts
Jun 1, 1995·The Journal of Cell Biology·M S Campbell, G J Gorbsky
Oct 1, 1994·The Biological Bulletin·E D SalmonA W Murray
Jan 1, 1997·Cell Motility and the Cytoskeleton·D A Wise, B R Brinkley
Nov 14, 1997·Proceedings of the National Academy of Sciences of the United States of America·Y LiR Benezra
Jun 12, 1998·The Journal of Cell Biology·J C WatersE D Salmon
Aug 15, 1998·Trends in Cell Biology·C L Rieder, E D Salmon
May 29, 2000·Science·K NasmythF Uhlmann
Jul 13, 2000·Cell·M DoblesP K Sorger
Jul 11, 2001·Novartis Foundation Symposium·K NasmythF Uhlmann
Sep 13, 2001·Molecular Biology of the Cell·B F McEwenT J Yen
Dec 6, 2001·Chromosoma·R C Balczon
Jul 16, 2003·Cell·Yinghui MaoDon W Cleveland
Jul 29, 2003·Chromosoma·Ron BalczonY M Bhatnagar
Jan 1, 1992·Trends in Cell Biology·B R BrinkleyR P Zinkowski
Aug 12, 2004·Cytogenetic and Genome Research·W B HerronD Wise
Oct 29, 2004·Journal of Cell Science·Helder MaiatoWilliam C Earnshaw
Jan 29, 2005·Oncogene·Anna CastroThierry Lorca
Aug 9, 2005·Trends in Cell Biology·Benjamin A Pinsky, Sue Biggins
Sep 8, 2005·The Journal of Cell Biology·Yinghui MaoDon W Cleveland
Oct 13, 2006·The Journal of Cell Biology·Song-Tao LiuTim J Yen
Oct 14, 2006·Journal of Cell Science·Karen M May, Kevin G Hardwick