title: Both actin and myosin inhibitors affect spindle architecture in PtK1 cells: does an actomyosin system contribute to mitotic spindle forces by regulating attachment and movements of chromosomes in mammalian cells?
abstract: Immunocytochemical techniques are used to analyze the effects of both an actin and myosin inhibitor on spindle architecture in PtK(1) cells to understand why both these inhibitors slow or block chromosome motion and detach chromosomes. Cytochalasin J, an actin inhibitor and a myosin inhibitor, 2, 3 butanedione 2-monoxime, have similar effects on changes in spindle organization. Using primary antibodies and stains, changes are studied in microtubule (MT), actin, myosin, and chromatin localization. Treatment of mitotic cells with both inhibitors results in detachment or misalignment of chromosomes from the spindle and a prominent buckling of MTs within the spindle, particularly evident in kinetochore fibers. Evidence is presented to suggest that an actomyosin system may help to regulate the initial and continued attachment of chromosomes to the mammalian spindle and could also influence spindle checkpoint(s).
authors.affiliation: Department of Biological Sciences, University of Denver, Denver, CO 80208, USA. jusnyder@du.edu
authors.forename: Judith A
authors.initials: JA
authors.lastname: Snyder
authors.forename: Yen
authors.initials: Y
authors.lastname: Ha
authors.forename: Claire
authors.initials: C
authors.lastname: Olsofka
authors.forename: Reema
authors.initials: R
authors.lastname: Wahdan
mesh_terms: D000199:Actins / Q000037:antagonists & inhibitors* / Q000502:physiology*; D000205:Actomyosin / Q000502:physiology; D000818:Animals; D001696:Biomechanical Phenomena; D002460:Cell Line; D045584:Chromosome Positioning / Q000187:drug effects / Q000502:physiology*; D003572:Cytochalasins / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D003931:Diacetyl / Q000031:analogs & derivatives / Q000494:pharmacology; D008677:Metaphase / Q000187:drug effects / Q000502:physiology; D008856:Microscopy, Fluorescence; D009218:Myosins / Q000037:antagonists & inhibitors* / Q000502:physiology*; D048328:Potoroidae; D008941:Spindle Apparatus / Q000187:drug effects* / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism
chemical_list: D000199:Actins; D003572:Cytochalasins; D014404:Tubulin; C106137:cytochalasin J; C004717:diacetylmonoxime; D004247:DNA; D000205:Actomyosin; D009218:Myosins; D003931:Diacetyl