title: Modulation of cytochemically detected dihydrofolate reductase during cell cycle.
abstract: Dihydrofolate reductase (DHFR, EC 1.5.1.3) is an important enzyme involved in DNA metabolism. In this connection the cell cycle modulation of DHFR levels in HeLa S3 and HL 60 cell lines was investigated by flow cytometric analysis. A concentration of 4 micrograms/ml of aphidicolin was employed to synchronize the cell lines. DHFR was cytochemically detected by using tetrazolium salt and immunofluorescence techniques; DNA content was evaluated by means of propidium iodide staining. At 0, 2, 4, 6, 8, 10, 12 hrs. after the removal of the drug we observed a low DHFR level in G0-G1 phase, followed by an increase during late S and G2/M phases. The variations of this enzyme may represent, under well defined conditions, a marker of cycling cells.
authors.affiliation: Dip. Biologia Animale, Università di Pavia e Centro di Studio per l'Istochimica del C.N.R., Italia.
authors.forename: R
authors.initials: R
authors.lastname: Nano
authors.forename: G
authors.initials: G
authors.lastname: Gerzeli
authors.forename: S
authors.initials: S
authors.lastname: Spadari
mesh_terms: D002453:Cell Cycle / Q000502:physiology*; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D006801:Humans; D013762:Tetrahydrofolate Dehydrogenase / Q000378:metabolism*; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D013778:Tetrazolium Salts; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase