ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.

Chromosome rearrangements can form when incorrect ends are matched during end joining (EJ) repair of multiple chromosomal double-strand breaks (DSBs). We tested whether the ATM kinase limits chromosome rearrangements via suppressing incorrect end utilization during EJ repair of multiple DSBs. For th...

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Main Authors: Nicole Bennardo, Jeremy M Stark
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2010-11-01
Series:PLoS Genetics
Online Access:https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1001194&type=printable
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author Nicole Bennardo
Jeremy M Stark
author_facet Nicole Bennardo
Jeremy M Stark
author_sort Nicole Bennardo
collection DOAJ
description Chromosome rearrangements can form when incorrect ends are matched during end joining (EJ) repair of multiple chromosomal double-strand breaks (DSBs). We tested whether the ATM kinase limits chromosome rearrangements via suppressing incorrect end utilization during EJ repair of multiple DSBs. For this, we developed a system for monitoring EJ of two tandem DSBs that can be repaired using correct ends (Proximal-EJ) or incorrect ends (Distal-EJ, which causes loss of the DNA between the DSBs). In this system, two DSBs are induced in a chromosomal reporter by the meganuclease I-SceI. These DSBs are processed into non-cohesive ends by the exonuclease Trex2, which leads to the formation of I-SceI-resistant EJ products during both Proximal-EJ and Distal-EJ. Using this method, we find that genetic or chemical disruption of ATM causes a substantial increase in Distal-EJ, but not Proximal-EJ. We also find that the increase in Distal-EJ caused by ATM disruption is dependent on classical non-homologous end joining (c-NHEJ) factors, specifically DNA-PKcs, Xrcc4, and XLF. We present evidence that Nbs1-deficiency also causes elevated Distal-EJ, but not Proximal-EJ, to a similar degree as ATM-deficiency. In addition, to evaluate the roles of these factors on end processing, we examined Distal-EJ repair junctions. We found that ATM and Xrcc4 limit the length of deletions, whereas Nbs1 and DNA-PKcs promote short deletions. Thus, the regulation of end processing appears distinct from that of end utilization. In summary, we suggest that ATM is important to limit incorrect end utilization during c-NHEJ.
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spelling doaj-art-521de2c139b44264ac9444512e93b60d2025-08-20T02:01:54ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042010-11-01611e100119410.1371/journal.pgen.1001194ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.Nicole BennardoJeremy M StarkChromosome rearrangements can form when incorrect ends are matched during end joining (EJ) repair of multiple chromosomal double-strand breaks (DSBs). We tested whether the ATM kinase limits chromosome rearrangements via suppressing incorrect end utilization during EJ repair of multiple DSBs. For this, we developed a system for monitoring EJ of two tandem DSBs that can be repaired using correct ends (Proximal-EJ) or incorrect ends (Distal-EJ, which causes loss of the DNA between the DSBs). In this system, two DSBs are induced in a chromosomal reporter by the meganuclease I-SceI. These DSBs are processed into non-cohesive ends by the exonuclease Trex2, which leads to the formation of I-SceI-resistant EJ products during both Proximal-EJ and Distal-EJ. Using this method, we find that genetic or chemical disruption of ATM causes a substantial increase in Distal-EJ, but not Proximal-EJ. We also find that the increase in Distal-EJ caused by ATM disruption is dependent on classical non-homologous end joining (c-NHEJ) factors, specifically DNA-PKcs, Xrcc4, and XLF. We present evidence that Nbs1-deficiency also causes elevated Distal-EJ, but not Proximal-EJ, to a similar degree as ATM-deficiency. In addition, to evaluate the roles of these factors on end processing, we examined Distal-EJ repair junctions. We found that ATM and Xrcc4 limit the length of deletions, whereas Nbs1 and DNA-PKcs promote short deletions. Thus, the regulation of end processing appears distinct from that of end utilization. In summary, we suggest that ATM is important to limit incorrect end utilization during c-NHEJ.https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1001194&type=printable
spellingShingle Nicole Bennardo
Jeremy M Stark
ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
PLoS Genetics
title ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
title_full ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
title_fullStr ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
title_full_unstemmed ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
title_short ATM limits incorrect end utilization during non-homologous end joining of multiple chromosome breaks.
title_sort atm limits incorrect end utilization during non homologous end joining of multiple chromosome breaks
url https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1001194&type=printable
work_keys_str_mv AT nicolebennardo atmlimitsincorrectendutilizationduringnonhomologousendjoiningofmultiplechromosomebreaks
AT jeremymstark atmlimitsincorrectendutilizationduringnonhomologousendjoiningofmultiplechromosomebreaks