Alagoz, M., Chiang, S. C., Sharma, A. et al. (1 more author) (2013) ATM deficiency results in accumulation of DNA-topoisomerase I covalent intermediates in neural cells. PLoS One, 8 (4). e58239. ISSN 1932-6203
Abstract
Accumulation of peptide-linked DNA breaks contributes to neurodegeration in humans. This is typified by defects in tyrosyl DNA phosphodiesterase 1 (TDP1) and human hereditary ataxia. TDP1 primarily operates at single-strand breaks (SSBs) created by oxidative stress or by collision of transcription machinery with topoisomerase I intermediates (Top1-CCs). Cellular and cell-free studies have shown that Top1 at stalled Top1-CCs is first degraded to a small peptide resulting in Top1-SSBs, which are the primary substrates for TDP1. Here we established an assay to directly compare Top1-SSBs and Top1-CCs. We subsequently employed this assay to reveal an increased steady state level of Top1-CCs in neural cells lacking Atm; the protein mutated in ataxia telangiectasia. Our data suggest that the accumulation of endogenous Top1-CCs in Atm-/- neural cells is primarily due to elevated levels of reactive oxygen species. Biochemical purification of Top1-CCs from neural cell extract and the use of Top1 poisons further confirmed a role for Atm during the formation/resolution of Top1-CCs. Finally, we report that global transcription is reduced in Atm-/- neural cells and fails to recover to normal levels following Top1-mediated DNA damage. Together, these data identify a distinct role for ATM during the formation/resolution of neural Top1-CCs and suggest that their accumulation contributes to the neuropathology of ataxia telangiectasia.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2013 Alagoz et al. 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. |
Keywords: | Astrocytes; Ataxia Telangiectasia Mutated Proteins; Biological Assay; Camptothecin; Cell Line; DNA Breaks, Single-Stranded; DNA Topoisomerases, Type I; Enzyme Inhibitors; Fibroblasts; Gene Expression Regulation; Humans; Morpholines; Oxidative Stress; Phosphoric Diester Hydrolases; Pyrones; Signal Transduction; Topoisomerase I Inhibitors; Transcription, Genetic |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) > Department of Molecular Biology and Biotechnology (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 05 Dec 2016 16:25 |
Last Modified: | 05 Dec 2016 16:31 |
Published Version: | http://dx.doi.org/10.1371/journal.pone.0058239 |
Status: | Published |
Publisher: | Public Library of Science |
Refereed: | Yes |
Identification Number: | 10.1371/journal.pone.0058239 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:108653 |