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Instability of pleomorphic tubulin paracrystals artificially induced by Vinca alkaloids in tissue‐cultured cells
Author(s) -
Takanari Hideki,
Yosida Toshimichi,
Morita Joji,
Izutsu Kosaku,
Ito Tadahiro
Publication year - 1990
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(90)90363-8
Subject(s) - colcemid , vinca , colchicine , tubulin , microtubule , vinca alkaloid , vinblastine , alkaloid , biophysics , biology , vicia , microbiology and biotechnology , vincristine , pharmacology , botany , chemotherapy , cyclophosphamide , vicia faba , genetics
Summary— The processes of tubulin paracrystal induction in Chinese hamster ovary cells treated with a Vinca alkaloid, ie , vinblastine or vincristine, and treated simultaneously with one of the Vinca alkaloids and colcemid or colchicine were followed by four different microscopic techniques, in particular by tubulin‐immunofluorescence. Vinca alkaloid alone, in lower concentrations, induced basically tactoid or needle‐shaped (N‐shaped) paracrystals. However, the formation of crystalloid was greatly enhanced by increasing the concentration of Vinca alkaloid. Square or barrel‐shaped (S‐shaped) and hexagonal paracrystals were also commonly induced by simultaneous treatment with a Vinca alkaloid and colcemid or colchicine. Large rectangular paracrystals often displayed fibrillar or lamellar fine structures which ran perpendicular to the long axis but tended to cleave into fragments by spontaneous splitting. Electron micrographs revealed the fine structure of crystalloids to be aggregates of numerous filaments. The growth of paracrystals, particularly N‐shaped crystals, was markedly inhibited when cells were exposed to drug(s) at a low temperature (4°C). We confirmed that both N‐ and S‐shaped paracrystals dissociated rapidly after the culture medium was replaced with fresh, drug‐free medium. Glutaraldehyde‐fixed paracrystals treated with RNase solution were stained with acridine orange, showing a weak orange color. Possible factors involved in the assembly and disassembly of tubulin paracrystals are discussed.