title: Centriole distribution during tripolar mitosis in Chinese hamster ovary cells.
abstract: During bipolar mitosis a pair of centrioles is distributed to each cell but the activities of the two centrioles within the pair are not equivalent. The parent is normally surrounded by a cloud of pericentriolar material that serves as a microtubule-organizing center. The daughter does not become associated with pericentriolar material until it becomes a parent in the next cell cycle (Rieder, C.L., and G. G. Borisy , 1982, Biol. Cell., 44:117-132). We asked whether the microtubule-organizing activity associated with a centriole was dependent on its becoming a parent. We induced multipolar mitosis in Chinese hamster ovary cells by treatment with 0.04 micrograms/ml colcemid for 4 h. After recovery from this colcemid block, the majority of cells divided into two, but 40% divided into three and 2% divided into four. The tripolar mitotic cells were examined by antitubulin immunofluorescence and by high voltage electron microscopy of serial thick (0.25-micron) sections. The electron microscope analysis showed that centriole number was conserved and that the centrioles were distributed among the three spindle poles, generally in a 2:1:1 or 2:2:0 pattern. The first pattern shows that centriole parenting is not prerequisite for association with pole function; the second pattern indicates that centrioles per se are not required at all. However, the frequency of midbody formation and successful division was higher when centrioles were present in the 2:1:1 pattern. We suggest that the centrioles may help the proper distribution and organization of the pericentriolar cloud, which is needed for the formation of a functional spindle pole.
mesh_terms: D000705:Anaphase; D000818:Animals; D002460:Cell Line; D002502:Centrioles / Q000502:physiology* / Q000648:ultrastructure; D006224:Cricetinae; D003412:Cricetulus; D003703:Demecolcine / Q000633:toxicity; D005260:Female; D005455:Fluorescent Antibody Technique; D008677:Metaphase; D008854:Microscopy, Electron; D008938:Mitosis / Q000187:drug effects; D009940:Organoids / Q000502:physiology*; D010053:Ovary; D013692:Telophase
chemical_list: D003703:Demecolcine