Topoisomerase II activity in a DNA double-strand break repair deficient Chinese hamster ovary cell line

Raymond L. Warters, Bradley W. Lyons, T. Mua Li, David J. Chen

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Topoisomerase II activity was measured in wild-type, Chinese hamster ovary K1 cells, and in the DNA double-strand break repair deficient xrs-6 cell line. Total topoisomerase II activity in a high salt, nuclear extract was found to be the same in both cell lines, as measured by decatenation of kinetoplast DNA networks and catenation of plasmid pBr322 DNA. While at low drug concentrations m-AMSA-induced enzyme cutting of nuclear DNA was 25% less in xrs-6 cells, the frequency of DNA breaks at high concentrations of the drug, and thus the frequency of the topoisomerase II enzyme, was the same in both cell lines. Despite the presence of equivalent enzyme levels in both cell lines, the xrs-6 cell line was 3 times more sensitive to drug-induced cytotoxicity. These results may be due to the fact that, as with X-radiation-induced DNA damage, xrs-6 cells are deficient in the capacity to rejoin topoisomerase II-induced DNA double-strand breaks.

Original languageEnglish (US)
Pages (from-to)167-174
Number of pages8
JournalMutation Research-DNA Repair
Volume254
Issue number2
DOIs
StatePublished - 1991

Fingerprint

Type II DNA Topoisomerase
Double-Stranded DNA Breaks
Cricetulus
Ovary
Repair
Cells
Cell Line
DNA
Enzymes
Kinetoplast DNA
Amsacrine
Pharmaceutical Preparations
DNA Breaks
DNA Damage
Cytotoxicity
Plasmids
Salts
X-Rays
Radiation

Keywords

  • Chinese hamster ovary cell line
  • DNA double-strand break repair
  • Topoisomerase II

ASJC Scopus subject areas

  • Genetics
  • Molecular Biology
  • Toxicology

Cite this

Topoisomerase II activity in a DNA double-strand break repair deficient Chinese hamster ovary cell line. / Warters, Raymond L.; Lyons, Bradley W.; Li, T. Mua; Chen, David J.

In: Mutation Research-DNA Repair, Vol. 254, No. 2, 1991, p. 167-174.

Research output: Contribution to journalArticle

Warters, Raymond L. ; Lyons, Bradley W. ; Li, T. Mua ; Chen, David J. / Topoisomerase II activity in a DNA double-strand break repair deficient Chinese hamster ovary cell line. In: Mutation Research-DNA Repair. 1991 ; Vol. 254, No. 2. pp. 167-174.
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