Mutational alteration of the breakage/resealing subunit of bacteriophage T4 DNA topoisomerase confers resistance to antitumor agent m-AMSA.

Journal Article (Journal Article)

Bacteriophage T4 provides a simple model system in which to examine the mechanism of action of antitumor agents that have been proposed to attack type II DNA topoisomerases. Prior results demonstrated that T4 type II DNA topoisomerase is the target of antitumor agent 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) in phage-infected Escherichia coli: a point mutation in topoisomerase structural gene 39 was shown to confer both m-AMSA-resistant phage growth and m-AMSA-insensitive topoisomerase activity. We report here that a point mutation in T4 topoisomerase structural gene 52 can also independently render both phage growth and topoisomerase activity resistant to m-AMSA. The DNA relaxation and DNA cleavage activities of this newly isolated mutant topoisomerase were significantly insensitive to m-AMSA. The drug-resistance mutation in gene 52, as well as that in gene 39, alters the DNA cleavage site specificity of wild-type T4 topoisomerase. This finding is consistent with a mechanism of drug action in which both topoisomerase and DNA participate in formation of the drug-binding site.

Full Text

Duke Authors

Cited Authors

  • Huff, AC; Ward, RE; Kreuzer, KN

Published Date

  • March 1990

Published In

Volume / Issue

  • 221 / 1

Start / End Page

  • 27 - 32

PubMed ID

  • 2157956

International Standard Serial Number (ISSN)

  • 0026-8925

Digital Object Identifier (DOI)

  • 10.1007/BF00280363


  • eng

Conference Location

  • Germany