Related Experiment Video
Updated: Oct 11, 2026

Measuring DNA Damage and Repair in Mouse Splenocytes After Chronic In Vivo Exposure to Very Low Doses of Beta- and Gamma-Radiation
Published on: July 3, 2015
Effects of modifying topoisomerase II levels on cellular recovery from radiation damage
D K Gaffney1, M Lundquist, R L Warters
1Department of Radiation Oncology, University of Utah Medical Center, Salt Lake City, Utah 84132, USA.
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.
Related Concept Videos
DNA Topoisomerases
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
DNA Damage can Stall the Cell Cycle
Inhibitors of Bacterial DNA Synthesis
