journal.pone.0058239.pdf (749.51 kB)
ATM deficiency results in accumulation of DNA-Topoisomerase I covalent intermediates in neural cells
journal contribution
posted on 2023-06-08, 14:45 authored by Meryem Alagoz, Shih-Chieh Chiang, Abhishek Sharma, Sherif F El-KhamisyAccumulation 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.
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- Published
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PLoS ONEISSN
1932-6203Publisher
Public Library of ScienceExternal DOI
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4Volume
8Article number
e58239Department affiliated with
- Clinical and Experimental Medicine Publications
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- Yes
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- Yes
Legacy Posted Date
2013-04-25First Open Access (FOA) Date
2013-04-25First Compliant Deposit (FCD) Date
2013-04-25Usage metrics
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