Microtubule function and its relation to cellular development and the yeast cell cycle in Wangiella dermatitidis.

The microtubule inhibitor nocodazole (methyl-5-[2-(thienylcarbonyl)-1H-benzimidazol-2-yl]-carbamate) prevented nuclear migration and nuclear division in yeasts and developing multicellular forms of the polymorphic fungus Wangiella dermatitidis. It did not prevent yeast bud formation during at least two or three budding cycles, and caused yeasts to accumulate as premitotic forms with one to three buds. The effects of the drug suggested that at least three control pathways were involved in the yeast cell cycle; that the nocodazole block point was separate from the execution points of two temperature-sensitive mutations which lead to multicellularity; and that microtubules were controlling neither the yeast budding process nor the development of multicellular forms.