title: Drug Stimulated DNA Cleavage Mediated by Cauliflower Topoisomerase II.
abstract: We have investigated cauliflower (Brassica oleracea) topoisomerase II with respect to its interaction with DNA and demonstrate that the enzyme shares the characteristics of topoisomerase II purified from a variety of phylogenetically remote organisms. In the presence of the 2-nitroimidazole Ro 15-0216, cauliflower topoisomerase II-mediated DNA cleavage is extensively stimulated (approximately 20-fold) only at a site recognized as a major cleavage site for the enzyme in the absence of drug. The conservation of the enzyme's DNA specificity in the presence of Ro 15-0216 is in contrast to the effect exerted by traditional topoisomerase II inhibitors, which cause enzyme-mediated cleavage to take place at a multiple number of DNA sites. Ro 15-0216 may therefore prove useful as a tool in the elucidation of the enzyme's DNA interaction sites and its involvement in nucleic acid metabolism in plant cells.
authors: Department of Molecular Biology and Plant Physiology, University of Aarhus, DK-8000 Arhus C, Denmark.
authors: B S
authors: BS
authors: Sørensen
authors: H
authors: H
authors: Fukata
authors: P S
authors: PS
authors: Jensen
authors: A H
authors: AH
authors: Andersen
authors: K
authors: K
authors: Christiansen
authors: H
authors: H
authors: Fukasawa
authors: O
authors: O
authors: Westergaard