Meczes, E.L., Gilroy, K.L., West, K.L. and Austin, C.A. (2008) The impact of the human DNA topoisomerase II C-terminal domain on activity. PLoS ONE, 3(3), e1754. (doi: 10.1371/journal.pone.0001754)
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Publisher's URL: http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0001754
Abstract
Background Type II DNA topoisomerases (topos) are essential enzymes needed for the resolution of topological problems that occur during DNA metabolic processes. Topos carry out an ATP-dependent strand passage reaction whereby one double helix is passed through a transient break in another. Humans have two topoII isoforms, α and β, which while enzymatically similar are differentially expressed and regulated, and are thought to have different cellular roles. The C-terminal domain (CTD) of the enzyme has the most diversity, and has been implicated in regulation. We sought to investigate the impact of the CTD domain on activity. Methodology/Principle Findings We have investigated the role of the human topoII C-terminal domain by creating constructs encoding C-terminally truncated recombinant topoIIα and β and topoIIα+β-tail and topoIIβ+α-tail chimeric proteins. We then investigated function in vivo in a yeast system, and in vitro in activity assays. We find that the C-terminal domain of human topoII isoforms is needed for in vivo function of the enzyme, but not needed for cleavage activity. C-terminally truncated enzymes had similar strand passage activity to full length enzymes, but the presence of the opposite C-terminal domain had a large effect, with the topoIIα-CTD increasing activity, and the topoIIβ-CTD decreasing activity. Conclusions/Significance In vivo complementation data show that the topoIIα C-terminal domain is needed for growth, but the topoIIβ isoform is able to support low levels of growth without a C-terminal domain. This may indicate that topoIIβ has an additional localisation signal. In vitro data suggest that, while the lack of any C-terminal domain has little effect on activity, the presence of either the topoIIα or β C-terminal domain can affect strand passage activity. Data indicates that the topoIIβ-CTD may be a negative regulator. This is the first report of in vitro data with chimeric human topoIIs.
Item Type: | Articles |
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Additional Information: | This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | West, Dr Katherine and Gilroy, Dr Kathryn |
Authors: | Meczes, E.L., Gilroy, K.L., West, K.L., and Austin, C.A. |
College/School: | College of Medical Veterinary and Life Sciences > School of Cancer Sciences |
Journal Name: | PLoS ONE |
Publisher: | Public Library of Science |
ISSN: | 1932-6203 |
ISSN (Online): | 1932-6203 |
Published Online: | 01 January 2008 |
Copyright Holders: | © 2008 Meczes et al |
First Published: | First published in PLoS ONE 2008 3(3): e1754 |
Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher |
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