Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

DNA end resection during homologous recombination.

ABSTRACT: Exposure to environmental mutagens but also cell-endogenous processes can create DNA double-strand breaks (DSBs) in a cell's genome. DSBs need to be repaired accurately and timely to ensure genomic integrity and cell survival. One major DSB repair mechanism, called homologous recombination, relies on the nucleolytic degradation of the 5'-terminated strands in a process termed end resection. Here, we review new insights into end resection with a focus on the mechanistic interplay of the nucleases, helicases, and accessory factors involved.

SUBMITTER: Gnugge R

PROVIDER: S-EPMC9006674 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

DNA end resection during homologous recombination.

Gnügge Robert R Symington Lorraine S LS

Current opinion in genetics & development 20210728

Exposure to environmental mutagens but also cell-endogenous processes can create DNA double-strand breaks (DSBs) in a cell's genome. DSBs need to be repaired accurately and timely to ensure genomic integrity and cell survival. One major DSB repair mechanism, called homologous recombination, relies on the nucleolytic degradation of the 5'-terminated strands in a process termed end resection. Here, we review new insights into end resection with a focus on the mechanistic interplay of the nucleases ...[more]

PMID: 34329854

Similar Datasets

RBM14 promotes DNA end resection during homologous recombination repair.

Project description:DNA double-strand break (DSB) repair by homologous recombination (HR) is crucial for the maintenance of genome stability and integrity. In this study, we aim to identify novel RNA binding proteins (RBPs) involved in HR repair because little is known about RBP function in HR. For this purpose, we carry out pulldown assays using a synthetic ssDNA/dsDNA structure coated with replication protein A (RPA) to mimic resected DNA, a crucial intermediate in HR-mediated DSB repair. Using this approach, we identify RNA-binding motif protein 14 (RBM14) as a potential binding partner. We further show that RBM14 interacts with an essential HR repair factor, CtIP. RBM14 is crucial for CtIP recruitment to DSB sites and for subsequent RPA coating and RAD51 replacement, facilitating efficient HR repair. Moreover, inhibition of RBM14 expression sensitizes cancer cells to X-ray irradiation. Together, our results demonstrate that RBM14 promotes DNA end resection to ensure HR repair and may serve as a potential target for cancer therapy.

| S-EPMC10753362 | biostudies-literature

PWWP2B promotes DNA end resection and homologous recombination.

Project description:Genome instability is one of the leading causes of gastric cancers. However, the mutational landscape of driver genes in gastric cancer is poorly understood. Here, we investigate somatic mutations in 25 Korean gastric adenocarcinoma patients using whole-exome sequencing and show that PWWP2B is one of the most frequently mutated genes. PWWP2B mutation correlates with lower cancer patient survival. We find that PWWP2B has a role in DNA double-strand break repair. As a nuclear protein, PWWP2B moves to sites of DNA damage through its interaction with UHRF1. Depletion of PWWP2B enhances cellular sensitivity to ionizing radiation (IR) and impairs IR-induced foci formation of RAD51. PWWP2B interacts with MRE11 and participates in homologous recombination via promoting DNA end-resection. Taken together, our data show that PWWP2B facilitates the recruitment of DNA repair machinery to sites of DNA damage and promotes HR-mediated DNA double-strand break repair. Impaired PWWP2B function might thus cause genome instability and promote gastric cancer development.

| S-EPMC9253748 | biostudies-literature

EXD2 promotes homologous recombination by facilitating DNA end resection.

Project description:Repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is critical for survival and genome stability of individual cells and organisms, but also contributes to the genetic diversity of species. A vital step in HR is MRN-CtIP-dependent end resection, which generates the 3' single-stranded DNA overhangs required for the subsequent strand exchange reaction. Here, we identify EXD2 (also known as EXDL2) as an exonuclease essential for DSB resection and efficient HR. EXD2 is recruited to chromatin in a damage-dependent manner and confers resistance to DSB-inducing agents. EXD2 functionally interacts with the MRN complex to accelerate resection through its 3'-5' exonuclease activity, which efficiently processes double-stranded DNA substrates containing nicks. Finally, we establish that EXD2 stimulates both short- and long-range DSB resection, and thus, together with MRE11, is required for efficient HR. This establishes a key role for EXD2 in controlling the initial steps of chromosomal break repair.

| S-EPMC4829102 | biostudies-literature

DNA Double-Strand Break Resection Occurs during Non-homologous End Joining in G1 but Is Distinct from Resection during Homologous Recombination.

Project description:Canonical non-homologous end joining (c-NHEJ) repairs DNA double-strand breaks (DSBs) in G1 cells with biphasic kinetics. We show that DSBs repaired with slow kinetics, including those localizing to heterochromatic regions or harboring additional lesions at the DSB site, undergo resection prior to repair by c-NHEJ and not alt-NHEJ. Resection-dependent c-NHEJ represents an inducible process during which Plk3 phosphorylates CtIP, mediating its interaction with Brca1 and promoting the initiation of resection. Mre11 exonuclease, EXD2, and Exo1 execute resection, and Artemis endonuclease functions to complete the process. If resection does not commence, then repair can ensue by c-NHEJ, but when executed, Artemis is essential to complete resection-dependent c-NHEJ. Additionally, Mre11 endonuclease activity is dispensable for resection in G1. Thus, resection in G1 differs from the process in G2 that leads to homologous recombination. Resection-dependent c-NHEJ significantly contributes to the formation of deletions and translocations in G1, which represent important initiating events in carcinogenesis.

| S-EPMC5316416 | biostudies-literature

SAMHD1 Promotes DNA End Resection to Facilitate DNA Repair by Homologous Recombination.

Project description:DNA double-strand break (DSB) repair by homologous recombination (HR) is initiated by CtIP/MRN-mediated DNA end resection to maintain genome integrity. SAMHD1 is a dNTP triphosphohydrolase, which restricts HIV-1 infection, and mutations are associated with Aicardi-Goutières syndrome and cancer. We show that SAMHD1 has a dNTPase-independent function in promoting DNA end resection to facilitate DSB repair by HR. SAMHD1 deficiency or Vpx-mediated degradation causes hypersensitivity to DSB-inducing agents, and SAMHD1 is recruited to DSBs. SAMHD1 complexes with CtIP via a conserved C-terminal domain and recruits CtIP to DSBs to facilitate end resection and HR. Significantly, a cancer-associated mutant with impaired CtIP interaction, but not dNTPase-inactive SAMHD1, fails to rescue the end resection impairment of SAMHD1 depletion. Our findings define a dNTPase-independent function for SAMHD1 in HR-mediated DSB repair by facilitating CtIP accrual to promote DNA end resection, providing insight into how SAMHD1 promotes genome integrity.

| S-EPMC5576576 | biostudies-literature

DNA end resection, homologous recombination and DNA damage checkpoint activation require CDK1.

Project description:A single double-strand break (DSB) induced by HO endonuclease triggers both repair by homologous recombination and activation of the Mec1-dependent DNA damage checkpoint in budding yeast. Here we report that DNA damage checkpoint activation by a DSB requires the cyclin-dependent kinase CDK1 (Cdc28) in budding yeast. CDK1 is also required for DSB-induced homologous recombination at any cell cycle stage. Inhibition of homologous recombination by using an analogue-sensitive CDK1 protein results in a compensatory increase in non-homologous end joining. CDK1 is required for efficient 5' to 3' resection of DSB ends and for the recruitment of both the single-stranded DNA-binding complex, RPA, and the Rad51 recombination protein. In contrast, Mre11 protein, part of the MRX complex, accumulates at unresected DSB ends. CDK1 is not required when the DNA damage checkpoint is initiated by lesions that are processed by nucleotide excision repair. Maintenance of the DSB-induced checkpoint requires continuing CDK1 activity that ensures continuing end resection. CDK1 is also important for a later step in homologous recombination, after strand invasion and before the initiation of new DNA synthesis.

| S-EPMC4493751 | biostudies-literature

Structural studies of DNA end detection and resection in homologous recombination.

Project description:DNA double-strand breaks are repaired by two major pathways, homologous recombination or nonhomologous end joining. The commitment to one or the other pathway proceeds via different steps of resection of the DNA ends, which is controlled and executed by a set of DNA double-strand break sensors, endo- and exonucleases, helicases, and DNA damage response factors. The molecular choreography of the underlying protein machinery is beginning to emerge. In this review, we discuss the early steps of genetic recombination and double-strand break sensing with an emphasis on structural and molecular studies.

| S-EPMC4176011 | biostudies-literature

CDK targets Sae2 to control DNA-end resection and homologous recombination.

Project description:DNA double-strand breaks (DSBs) are repaired by two principal mechanisms: non-homologous end-joining (NHEJ) and homologous recombination (HR). HR is the most accurate DSB repair mechanism but is generally restricted to the S and G2 phases of the cell cycle, when DNA has been replicated and a sister chromatid is available as a repair template. By contrast, NHEJ operates throughout the cell cycle but assumes most importance in G1 (refs 4, 6). The choice between repair pathways is governed by cyclin-dependent protein kinases (CDKs), with a major site of control being at the level of DSB resection, an event that is necessary for HR but not NHEJ, and which takes place most effectively in S and G2 (refs 2, 5). Here we establish that cell-cycle control of DSB resection in Saccharomyces cerevisiae results from the phosphorylation by CDK of an evolutionarily conserved motif in the Sae2 protein. We show that mutating Ser 267 of Sae2 to a non-phosphorylatable residue causes phenotypes comparable to those of a sae2Delta null mutant, including hypersensitivity to camptothecin, defective sporulation, reduced hairpin-induced recombination, severely impaired DNA-end processing and faulty assembly and disassembly of HR factors. Furthermore, a Sae2 mutation that mimics constitutive Ser 267 phosphorylation complements these phenotypes and overcomes the necessity of CDK activity for DSB resection. The Sae2 mutations also cause cell-cycle-stage specific hypersensitivity to DNA damage and affect the balance between HR and NHEJ. These findings therefore provide a mechanistic basis for cell-cycle control of DSB repair and highlight the importance of regulating DSB resection.

| S-EPMC2635538 | biostudies-literature

Persistently bound Ku at DNA ends attenuates DNA end resection and homologous recombination.

Project description:DNA double strand breaks (DSBs) are repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). The DNA cell cycle stage and resection of the DSB ends are two key mechanisms which are believed to push DSB repair to the HR pathway. Here, we show that the NHEJ factor Ku80 associates with DSBs in S phase, when HR is thought to be the preferred repair pathway, and its dynamics/kinetics at DSBs is similar to those observed for Ku80 in non-S phase in mammalian cells. A Ku homolog from Mycobacterium tuberculosis binds to and is retained at DSBs in S phase and was used as a tool to determine if blocking DNA ends affects end resection and HR in mammalian cells. A decrease in DNA end resection, as marked by IR-induced RPA, BrdU, and Rad51 focus formation, and HR are observed when Ku deficient rodent cells are complemented with Mt-Ku. Together, this data suggests that Ku70/80 binds to DSBs in all cell cycle stages and is likely actively displaced from DSB ends to free the DNA ends for DNA end resection and thus HR to occur.

| S-EPMC3297478 | biostudies-literature

ATR-binding lncRNA ScaRNA2 promotes cancer resistance through facilitating efficient DNA end resection during homologous recombination repair.

Project description:BackgroundOur previous study first showed that ATR-binding long noncoding RNA (lncRNA) is necessary for ATR function and promotes cancer resistance. However, the specific lncRNAs instrumental in ATR activation remain largely unclear, which limits our comprehensive understanding of this critical biological process.MethodsRNA immunoprecipitation (RIP) followed by RNA sequencing was employed to identify ATR-binding lncRNAs, which were further validated using RIP-qPCR assays. Immunofluorescence staining and Western blotting were applied to detect the activation of DNA damage repair factors. After the effect of scaRNA2 on cellular sensitivity to DNA-damaging reagents was determined, the effects of scaRNA2 on radiotherapy were investigated in patient-derived organoids and xenograft preclinical models. The clinical relevance of scaRNA2 was also validated in tissues isolated from rectal cancer patients.ResultsScaRNA2 was identified as the most enriched ATR-binding lncRNA and was found to be essential for homologous recombination (HR) mediated DNA damage repair. Furthermore, scaRNA2 knockdown abrogated the recruitment of ATR and its substrates in response to DNA damage. Mechanistically, scaRNA2 was observed to be necessary for Exo1-mediated DNA end resection and bridged the MRN complex to ATR activation. Knockdown of scaRNA2 effectively increased the sensitivity of cancer cells to multiple kinds of DNA damage-related chemoradiotherapy. Preclinically, knockdown of scaRNA2 improved the effects of radiotherapy on patient-derived organoids and xenograft models. Finally, an increase in scaRNA2 colocalized with ATR was also found in clinical patients who were resistant to radiotherapy.ConclusionsScaRNA2 was identified as the most abundant lncRNA bound to ATR and was demonstrated to bridge DNA end resection to ATR activation; thus, it could be applied as a potent target for combined cancer treatments with chemoradiotherapy.

| S-EPMC10542231 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data