title: Effects of modifying topoisomerase II levels on cellular recovery from radiation damage.
abstract: Effects of Modifying Topoisomerase II Levels on Cellular Recovery from Radiation Damage. Experiments were performed with the budding yeast, Saccharomyces cerevisiae, to test whether DNA topoisomerase II is involved in repair of DNA damage induced by ionizing radiation. Topoisomerase II was inactivated by use of a temperature-sensitive mutation. Enzyme inactivation increased cellular radiosensitivity, blocked the restitution of broken chromosomes, assayed by pulsed-field gel electrophoresis, and prolonged the induction of a DNA damage-inducible gene (RNR3). Overexpression of the topoisomerase II gene did not alter cellular radiosensitivity. The data support a role for topoisomerase II in the repair of DNA strand breaks.
authors.affiliation: Department of Radiation Oncology, University of Utah Medical Center, Salt Lake City, Utah 84132, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Gaffney
authors.forename: M
authors.initials: M
authors.lastname: Lundquist
authors.forename: R L
authors.initials: RL
authors.lastname: Warters
authors.forename: R
authors.initials: R
authors.lastname: Rosley
mesh_terms: D015825:Chromosomes, Fungal / Q000528:radiation effects / Q000648:ultrastructure; D004249:DNA Damage; D004260:DNA Repair; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000502:physiology*; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D016521:Electrophoresis, Gel, Pulsed-Field; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000528:radiation effects; D017930:Genes, Reporter; D006358:Hot Temperature; D009675:Novobiocin / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011836:Radiation Tolerance / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects*; D059005:Topoisomerase II Inhibitors
chemical_list: D004271:DNA, Fungal; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D059005:Topoisomerase II Inhibitors; D009675:Novobiocin; D004250:DNA Topoisomerases, Type II