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J Biochem. 2016 Mar;159(3):363-9. doi: 10.1093/jb/mvv110. Epub 2015 Nov 1.

DNA-binding activity of rat DNA topoisomerase II α C-terminal domain contributes to efficient DNA catenation in vitro.

Author information

1
Department of Biochemistry, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan and kawanos@dbc.ous.ac.jp.
2
Department of Biochemistry, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan and.
3
Department of Neurogenomics, Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.

Abstract

DNA topoisomerase IIα (topo IIα) is an essential enzyme for resolution of DNA topologies arising in DNA metabolic reactions. In proliferating cells, topo II activities of DNA catenation or decatenation are required for condensation of chromosomes and segregation of chromatids. Recent studies suggest that the C-terminal domain (CTD) of human topo IIα is required for localization to mitotic chromosomes. Here, we show that the CTD of topo IIα is also associated with efficient DNA catenation in vitro, based on comparison of wild-type (WT) rat topo IIα and its deletion mutants. Unlike WT, the CTD truncated mutant (ΔCTD) lacked linear DNA binding activity, but could bind to negatively supercoiled DNA similarly to WT. The CTD alone showed linear DNA-binding activity. ΔCTD mediated formation of a DNA catenane in the presence of polyethylene glycol, which enhances macromolecular association. These results indicate that DNA-binding activity in the CTD of topo IIα concentrates the enzyme in the vicinity of condensed DNA and allows topo IIα to efficiently form a DNA catenane.

KEYWORDS:

C-terminal domain; DNA-binding; catenation; topoisomerase II; α isoform

PMID:
26527691
DOI:
10.1093/jb/mvv110
[Indexed for MEDLINE]

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