In vivo mapping of DNA topoisomerase II-specific cleavage sites on SV40 chromatin

Liu Yang, Thomas C. Rowe, Eric M. Nelson, Leroy F. Liu

Research output: Contribution to journalArticlepeer-review

120 Citations (Scopus)


The antitumor drug, m-AMSA (4′-(9-acridinylamino)-methanesulfon-m-anisidide), is known to interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II by blocking the enzyme-DNA complex in its putative cleavable state. Treatment of SV40 virus infected monkey cells with m-AMSA resulted in both single- and double-stranded breaks on SV40 viral chromatin. These strand breaks are unusual because they are covalently associated with protein. Immuno-precipitation results suggest that the covalently linked protein is DNA topoisomerase II. These results are consistent with the proposal that the drug action in vivo involves the stabilization of a cleavable complex between topoisomerase II and DNA in chromatin. Mapping of these double-stranded breaks on SV40 viral DNA revealed multiple topoisomerase II cleavage sites. A major topoisomerase II cleavage site was preferentially induced during late infection and was mapped in the DNAase I hypersensitive region of SV40 chromatin.

Original languageEnglish
Pages (from-to)127-132
Number of pages6
Issue number1
Publication statusPublished - May 1985
Externally publishedYes

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology


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