Roles of DNA topoisomerases in simian virus 40 DNA replication in vitro

L. Yang, M. S. Wold, J. J. Li, T. J. Kelly, Leroy-Fong Liu

Research output: Contribution to journalArticle

229 Citations (Scopus)

Abstract

We examined the roles of DNA topoisomerases in the replication of simian virus 40 (SV40) DNA in a cell-free system composed of an extract from HeLa cells supplemented with purified SV40 tumor antigen. When the activities of both topoisomerase I (EC 5.99.1.2) and topoisomerase II (EC 5.99.1.3) in the extract were blocked with specific inhibitors or antibodies, DNA synthesis was decreased by a factor of 15-20. Addition of purified HeLa DNA topoisomerase II to extracts immunologically depleted of both topoisomerases completely restored replication, and the replication products consisted largely of monomeric daughter molecules. Addition of purified HeLa DNA topoisomerase I to depleted extracts restored DNA synthesis, but the primary products were multiply intertwined, catenated daughter molecules. We conclude that DNA topoisomerases have at least two roles in the replication of SV40 DNA. Either topoisomerase I or topoisomerase II is sufficient to provide the unlinking activity necessary for fork propagation during SV40 DNA replication. However, topoisomerase II is uniquely required for the segregation of newly synthesized daughter molecules.

Original languageEnglish
Pages (from-to)950-954
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume84
Issue number4
DOIs
Publication statusPublished - 1987
Externally publishedYes

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DNA Topoisomerases
Type II DNA Topoisomerase
Simian virus 40
DNA Replication
Type I DNA Topoisomerase
DNA
Cell-Free System
Neoplasm Antigens
HeLa Cells
In Vitro Techniques
Antibodies

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Roles of DNA topoisomerases in simian virus 40 DNA replication in vitro. / Yang, L.; Wold, M. S.; Li, J. J.; Kelly, T. J.; Liu, Leroy-Fong.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 84, No. 4, 1987, p. 950-954.

Research output: Contribution to journalArticle

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