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Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice

To repair ionizing radiation (IR)-induced double strand breaks (DSBs), mammalian cells primarily use canonical non-homologous end-joining (cNHEJ), the homologous recombination (HR) pathway, and the alternative non-homologous end-joining (aEJ) as a backup. These pathways function either compensativel...

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Autores principales: Li, Zhentian, Wang, Ya
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10380458/
https://www.ncbi.nlm.nih.gov/pubmed/37511594
http://dx.doi.org/10.3390/ijms241411836
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author Li, Zhentian
Wang, Ya
author_facet Li, Zhentian
Wang, Ya
author_sort Li, Zhentian
collection PubMed
description To repair ionizing radiation (IR)-induced double strand breaks (DSBs), mammalian cells primarily use canonical non-homologous end-joining (cNHEJ), the homologous recombination (HR) pathway, and the alternative non-homologous end-joining (aEJ) as a backup. These pathways function either compensatively or competitively. High linear energy transfer (LET) compared to low-LET IR kills more cells at the same doses by inhibiting only cNHEJ, but not HR or aEJ. The mechanism remains unclear. The activation of each repair pathway requires the binding of different proteins to DNA fragments of varying lengths. We previously observed an increased generation of small DNA fragments (≤40 bp) in cells following high-LET IR compared to low-LET IR, suggesting that short DNA fragments were one of the major factors interfering with cNHEJ. To provide direct evidence, here we compare the efficiencies of cNHEJ, HR, or aEJ in repairing DSBs containing 30- or 60-bp fragments in vitro and in cells. We show that only cNHEJ but not HR or a-EJ was inefficient for repairing DSBs with 30-bp fragments compared to 60-bp ones, which strongly supports our hypothesis. These results not only enhance our understanding of the DSB repair pathway choice but also hold potential benefits for protection against high-LET IR-induced damage or improving high-LET radiotherapy.
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spelling pubmed-103804582023-07-29 Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice Li, Zhentian Wang, Ya Int J Mol Sci Article To repair ionizing radiation (IR)-induced double strand breaks (DSBs), mammalian cells primarily use canonical non-homologous end-joining (cNHEJ), the homologous recombination (HR) pathway, and the alternative non-homologous end-joining (aEJ) as a backup. These pathways function either compensatively or competitively. High linear energy transfer (LET) compared to low-LET IR kills more cells at the same doses by inhibiting only cNHEJ, but not HR or aEJ. The mechanism remains unclear. The activation of each repair pathway requires the binding of different proteins to DNA fragments of varying lengths. We previously observed an increased generation of small DNA fragments (≤40 bp) in cells following high-LET IR compared to low-LET IR, suggesting that short DNA fragments were one of the major factors interfering with cNHEJ. To provide direct evidence, here we compare the efficiencies of cNHEJ, HR, or aEJ in repairing DSBs containing 30- or 60-bp fragments in vitro and in cells. We show that only cNHEJ but not HR or a-EJ was inefficient for repairing DSBs with 30-bp fragments compared to 60-bp ones, which strongly supports our hypothesis. These results not only enhance our understanding of the DSB repair pathway choice but also hold potential benefits for protection against high-LET IR-induced damage or improving high-LET radiotherapy. MDPI 2023-07-23 /pmc/articles/PMC10380458/ /pubmed/37511594 http://dx.doi.org/10.3390/ijms241411836 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Li, Zhentian
Wang, Ya
Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title_full Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title_fullStr Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title_full_unstemmed Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title_short Short Double-Stranded DNA (≤40-bp) Affects Repair Pathway Choice
title_sort short double-stranded dna (≤40-bp) affects repair pathway choice
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10380458/
https://www.ncbi.nlm.nih.gov/pubmed/37511594
http://dx.doi.org/10.3390/ijms241411836
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