title: Trichomonas vaginalis: dominant G2 period and G2 phase arrest in a representative of an early branching eukaryotic lineage.
abstract: Eukaryotic mitotic cell cycles have been extensively studied in yeasts and vertebrate cells but little is known about cell cycle mechanisms in early branches of the eukaryotic lineage. Trichomonas vaginalis represents one of the earliest branching eukaryotic lineages available for study. In contrast with most yeasts and vertebrate cells, the T. vaginalis G2 period was prolonged, comprising 50 to 58% of the cell population. Hydroxyurea, aphidicolin, and excess thymidine, all of which arrest yeasts and vertebrate cells at the G1/S phase boundary, had no effect on the T. vaginalis cell cycle, probably due to the known absence of synthetic pathways. The anti-microtubule mitotic inhibitors, colchicine and nocodazole, induced G2 phase synchrony. Metronidazole, a therapeutic reagent, also caused G2 phase arrest. These observations suggest that T. vaginalis is similar to yeasts and vertebrate cells in G2 and M phases, but the parasite's G1/S phase transition is distinctive. The results also suggest potentially therapeutic, anti-trichomonad activity of microtubule inhibitors such as nocodazole. The cultured parasite may prove useful as a model for the mitotic cell cycle in the absence of G1/S phase transitional activities universal in yeasts and vertebrate cells.
authors.affiliation: Department of Urology, University of Washington School of Medicine, Seattle 98195.
authors.forename: D E
authors.initials: DE
authors.lastname: Riley
authors.forename: J N
authors.initials: JN
authors.lastname: Krieger
authors.forename: D
authors.initials: D
authors.lastname: Miner
authors.forename: P S
authors.initials: PS
authors.lastname: Rabinovitch
mesh_terms: D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D003078:Colchicine / Q000494:pharmacology; D016054:DNA, Protozoan / Q000096:biosynthesis; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects; D016195:G2 Phase / Q000187:drug effects*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D008297:Male; D008795:Metronidazole / Q000494:pharmacology; D015739:Nocodazole / Q000494:pharmacology; D013936:Thymidine / Q000494:pharmacology; D014246:Trichomonas vaginalis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification
chemical_list: D016054:DNA, Protozoan; D008795:Metronidazole; D016590:Aphidicolin; D015739:Nocodazole; D003078:Colchicine; D013936:Thymidine; D006918:Hydroxyurea