Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress
Abstract Background Mutations in genes associated with homologous recombination (HR) increase an individual’s risk of developing triple-negative breast cancer (TNBC). Although known for their role in repairing dsDNA breaks, HR repair elements also stabilize and restart stalled replication forks. Ess...
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doaj-1fd0c61af2304bf5b0389420b309c0472021-04-02T15:08:42ZengBMCBreast Cancer Research1465-542X2019-11-0121111410.1186/s13058-019-1207-zLoss of SIM2s inhibits RAD51 binding and leads to unresolved replication stressScott J. Pearson0Jessica Elswood1Rola Barhoumi2Brittini Ming-Whitfield3Monique Rijnkels4Weston W. Porter5Department of Integrative Biosciences, College of Veterinary Medicine, Texas A&M UniversityDepartment of Integrative Biosciences, College of Veterinary Medicine, Texas A&M UniversityDepartment of Integrative Biosciences, College of Veterinary Medicine, Texas A&M UniversityDepartment of Molecular and Cellular Medicine, Texas A&M UniversityDepartment of Integrative Biosciences, College of Veterinary Medicine, Texas A&M UniversityDepartment of Integrative Biosciences, College of Veterinary Medicine, Texas A&M UniversityAbstract Background Mutations in genes associated with homologous recombination (HR) increase an individual’s risk of developing triple-negative breast cancer (TNBC). Although known for their role in repairing dsDNA breaks, HR repair elements also stabilize and restart stalled replication forks. Essential to these functions are RAD51 and its paralogs, each of which has a unique role in preventing replication fork collapse and restart. However, progress toward understanding the regulation of these factors has been slow. With such a pivotal role in the maintenance of genomic integrity, furthering our understanding of this pathway through the discovery of new factors involved in HR is important. Recently, we showed that singleminded-2s (SIM2s) is stabilized in response to dsDNA breaks and is required for effective HR. Methods Initial analysis of the effect loss of SIM2s has on replication stress resolution was conducted using DNA combing assays in established breast cancer cell lines. Further analysis was conducted via immunostaining to determine the effect loss of SIM2s has on factor recruitment. In vivo confirmation was achieved through the use of a mammary epithelial cell conditional knockout mouse model before SIM2s’ role in RAD51 recruitment was determined by immunoblotting. Results Here, we show loss of SIM2s decreases replication fork stability, leading to fork collapse in response to genotoxic stress. Furthermore, loss of SIM2s results in aberrant separation of sister chromatids during mitosis, which has been previously shown to result in chromosomal fragmentation and aneuploidy. Interestingly, loss of SIM2s was shown to result in failure of RAD51 to localize to sites of replication stress in both breast cancer cell lines and primary mammary epithelial cells. Finally, we observed SIM2 is stabilized in response to genotoxic stress and interacts with RAD51, which is necessary for RAD51-DNA binding. Conclusions Together, these results show a role for SIM2s in the resolution of replication stress and further characterize the necessity of SIM2s for effective RAD51 loading in response to DNA damage or stress, ultimately promoting genomic integrity and thus preventing the accumulation of cancer-promoting mutations.http://link.springer.com/article/10.1186/s13058-019-1207-zBreast cancerTumor suppressorGenetic instabilitySIM2Replication stress |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Scott J. Pearson Jessica Elswood Rola Barhoumi Brittini Ming-Whitfield Monique Rijnkels Weston W. Porter |
spellingShingle |
Scott J. Pearson Jessica Elswood Rola Barhoumi Brittini Ming-Whitfield Monique Rijnkels Weston W. Porter Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress Breast Cancer Research Breast cancer Tumor suppressor Genetic instability SIM2 Replication stress |
author_facet |
Scott J. Pearson Jessica Elswood Rola Barhoumi Brittini Ming-Whitfield Monique Rijnkels Weston W. Porter |
author_sort |
Scott J. Pearson |
title |
Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress |
title_short |
Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress |
title_full |
Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress |
title_fullStr |
Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress |
title_full_unstemmed |
Loss of SIM2s inhibits RAD51 binding and leads to unresolved replication stress |
title_sort |
loss of sim2s inhibits rad51 binding and leads to unresolved replication stress |
publisher |
BMC |
series |
Breast Cancer Research |
issn |
1465-542X |
publishDate |
2019-11-01 |
description |
Abstract Background Mutations in genes associated with homologous recombination (HR) increase an individual’s risk of developing triple-negative breast cancer (TNBC). Although known for their role in repairing dsDNA breaks, HR repair elements also stabilize and restart stalled replication forks. Essential to these functions are RAD51 and its paralogs, each of which has a unique role in preventing replication fork collapse and restart. However, progress toward understanding the regulation of these factors has been slow. With such a pivotal role in the maintenance of genomic integrity, furthering our understanding of this pathway through the discovery of new factors involved in HR is important. Recently, we showed that singleminded-2s (SIM2s) is stabilized in response to dsDNA breaks and is required for effective HR. Methods Initial analysis of the effect loss of SIM2s has on replication stress resolution was conducted using DNA combing assays in established breast cancer cell lines. Further analysis was conducted via immunostaining to determine the effect loss of SIM2s has on factor recruitment. In vivo confirmation was achieved through the use of a mammary epithelial cell conditional knockout mouse model before SIM2s’ role in RAD51 recruitment was determined by immunoblotting. Results Here, we show loss of SIM2s decreases replication fork stability, leading to fork collapse in response to genotoxic stress. Furthermore, loss of SIM2s results in aberrant separation of sister chromatids during mitosis, which has been previously shown to result in chromosomal fragmentation and aneuploidy. Interestingly, loss of SIM2s was shown to result in failure of RAD51 to localize to sites of replication stress in both breast cancer cell lines and primary mammary epithelial cells. Finally, we observed SIM2 is stabilized in response to genotoxic stress and interacts with RAD51, which is necessary for RAD51-DNA binding. Conclusions Together, these results show a role for SIM2s in the resolution of replication stress and further characterize the necessity of SIM2s for effective RAD51 loading in response to DNA damage or stress, ultimately promoting genomic integrity and thus preventing the accumulation of cancer-promoting mutations. |
topic |
Breast cancer Tumor suppressor Genetic instability SIM2 Replication stress |
url |
http://link.springer.com/article/10.1186/s13058-019-1207-z |
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