Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide

The role of topoisomerase IIβ was investigated in cell lines exposed to two DNA damaging agents, ionising radiation (IR) or etoposide, a drug which acts on topoisomerase II. The appearance and resolution of γH2AX foci in murine embryonic fibroblast cell lines, wild type and null for DNA topoisomera...

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Main Authors: Nicola J. Sunter, Ian G. Cowell, Elaine Willmore, Gary P. Watters, Caroline A. Austin
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:Journal of Nucleic Acids
Online Access:http://dx.doi.org/10.4061/2010/710589
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author Nicola J. Sunter
Ian G. Cowell
Elaine Willmore
Gary P. Watters
Caroline A. Austin
author_facet Nicola J. Sunter
Ian G. Cowell
Elaine Willmore
Gary P. Watters
Caroline A. Austin
author_sort Nicola J. Sunter
collection DOAJ
description The role of topoisomerase IIβ was investigated in cell lines exposed to two DNA damaging agents, ionising radiation (IR) or etoposide, a drug which acts on topoisomerase II. The appearance and resolution of γH2AX foci in murine embryonic fibroblast cell lines, wild type and null for DNA topoisomerase IIβ, was measured after exposure to ionising radiation (IR) or etoposide. Topoisomerase II-DNA adduct levels were also measured. IR rapidly triggered phosphorylation of histone H2AX, less phosphorylation was seen in TOP2β-/- cells, but the difference was not statistically significant. IR did not produce topoisomerase II-DNA adducts above control levels. Etoposide triggered the formation of topoisomerase II-DNA adducts and the phosphorylation of histone H2AX, the γH2AX foci appeared more slowly with etoposide than with IR. Topoisomerase II-DNA complexes in WT cells but not TOP2β-/- cells increased significantly at 24 hours with the proteasome inhibitor MG132, suggesting topoisomerase IIβ adducts are removed by the proteasome.
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spelling doaj-art-e0215dca65734e43a08a095cc6106d092025-08-20T02:21:26ZengWileyJournal of Nucleic Acids2090-021X2010-01-01201010.4061/2010/710589710589Role of Topoisomerase IIβ in DNA Damage Response following IR and EtoposideNicola J. Sunter0Ian G. Cowell1Elaine Willmore2Gary P. Watters3Caroline A. Austin4Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UKInstitute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UKInstitute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UKInstitute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UKInstitute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UKThe role of topoisomerase IIβ was investigated in cell lines exposed to two DNA damaging agents, ionising radiation (IR) or etoposide, a drug which acts on topoisomerase II. The appearance and resolution of γH2AX foci in murine embryonic fibroblast cell lines, wild type and null for DNA topoisomerase IIβ, was measured after exposure to ionising radiation (IR) or etoposide. Topoisomerase II-DNA adduct levels were also measured. IR rapidly triggered phosphorylation of histone H2AX, less phosphorylation was seen in TOP2β-/- cells, but the difference was not statistically significant. IR did not produce topoisomerase II-DNA adducts above control levels. Etoposide triggered the formation of topoisomerase II-DNA adducts and the phosphorylation of histone H2AX, the γH2AX foci appeared more slowly with etoposide than with IR. Topoisomerase II-DNA complexes in WT cells but not TOP2β-/- cells increased significantly at 24 hours with the proteasome inhibitor MG132, suggesting topoisomerase IIβ adducts are removed by the proteasome.http://dx.doi.org/10.4061/2010/710589
spellingShingle Nicola J. Sunter
Ian G. Cowell
Elaine Willmore
Gary P. Watters
Caroline A. Austin
Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
Journal of Nucleic Acids
title Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
title_full Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
title_fullStr Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
title_full_unstemmed Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
title_short Role of Topoisomerase IIβ in DNA Damage Response following IR and Etoposide
title_sort role of topoisomerase iiβ in dna damage response following ir and etoposide
url http://dx.doi.org/10.4061/2010/710589
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