Transcriptome changes of Hela cells with blocking classical and alternative non-homologous end-joining (NHEJ) pathways
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ABSTRACT:
PROVIDER: PRJNA558142 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR9886790_1.fastq.gz | Fastqsanger.gz | |||
| SRR9886790_2.fastq.gz | Fastqsanger.gz | |||
| SRR9886791_1.fastq.gz | Fastqsanger.gz | |||
| SRR9886791_2.fastq.gz | Fastqsanger.gz | |||
| SRR9886792_1.fastq.gz | Fastqsanger.gz |
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Project description:Purpose: The recombinant endonucleases introduce double-strand breaks (DSBs) in genomic DNA at targeted sites and non-homologous end-joining (NHEJ) pathways repair the breaks introducing indels into the genome. To investigate whether there is another NHEJ pathway or if A-NHEJ and C-NHEJ are redundant, we examined NHEJ edits in HeLa cells. Methods: To test among these possibilities, we engineered a NHEJ reporter system using targeted TALEN induced double strand DNA breaks. C-NHEJ was blocked in XRCC4(-/-) cells and A-NHEJ was blocked pharmacologically with mirin. To assess how NHEJ was maintained, differentially expressed genes were determined by RNA-Seq. Results: When both C-NHEJ and A-NHEJ are blocked, edits were still observed. No changes in expression of DNA repair genes was observed. However, when both NHEJ pathways were blocked, genes from several pathways including DNA damage response, hypoxic response, chromatin packaging, p53 response and two genes that stimulate homologous recombination were differentially expressed. Conclusions: NHEJ is maintained when both NHEJ pathways are blocked through a transcriptional response that must compensate for the inhibited steps in both pathways.
2020-12-31 | GSE135274 | GEO
Project description:Classical non-homologous end-joining (C-NHEJ) is a major mammalian DNA double strand break (DSB) repair pathway. Core C-NHEJ factors, such as XRCC4, are required for joining DSB intermediates of the G1 phase-specific V(D)J recombination reaction in progenitor lymphocytes. Core factors also contribute to joining DSBs in cycling mature B-lineage cells, including DSBs generated during antibody class switch recombination (CSR) and DSBs generated by ionizing radiation (IR). The XLF C-NHEJ factor is dispensable for V(D)J recombination in normal cells, but, due to functional redundancy, is absolutely required for this process in cells deficient for the ATM DSB response factor. The recently identified PAralogue of XRCC4 and XLF (PAXX) factor has homology to these two proteins and variably contributes to IR-induced DSB repair in human and chicken cells. We now report that PAXX is dispensable for joining V(D)J recombination DSBs in G1-arrested mouse pro-B cell lines, dispensable for joining CSR-associated DSBs in a cycling mouse B cell line, and dispensable for normal IR-resistance in both G1-arrested and cycling pro-B lines. However, we find that combined deficiency for PAXX and XLF in G1-arrested pro-B lines abrogates DSB joining during V(D)J recombination and sensitizes the cells to IR exposure. Thus, PAXX provides core C-NHEJ factor-associated functions in the absence of XLF and vice versa in G1-arrested Pro-B cell lines. Finally, we also find that PAXX-deficiency has no impact on V(D)J recombination DSB joining in ATM-deficient pro-B lines. We discuss implications of these findings with respect to potential PAXX and XLF functions in C-NHEJ. Examination of CSR Switch mu-to-alpha junctions from mu bait DSBs using LAM-HTGTS and Illumina Miseq. Two clones of PAXX-/- and XLF-/- and 1 clone of Ligase4-/- were derived from the parental CH12F3 line; the second Ligase4-/- clone was acquired from Keifei Yu. Two clones of XLF-/-PAXX-/-CH12 cells were derived from one of the PAXX-/- clones. Three biological replicates were analyzed for each clone.
2016-08-19 | E-GEOD-84102 | biostudies-arrayexpress
Project description:DNA double strand breaks (DSBs) are a major source of mutations. Both non-homologous-end-joining (NHEJ) and microhomology-mediated-end-joining (MMEJ) DSB repair pathways are error prone and produce deletions, which can lead to cancer. DSBs also lead to epigenetic changes, including demethylation, which is involved in carcinogenesis. Of specific interest is the MMEJ repair pathway, as it requires methylation restoration around the break, as a result of the resection and formation of single stranded (ssDNA) intermediates. While, methylation patterns after homologous recombination (HR) have been partially studied, the methylation status after MMEJ and NHEJ remains poorly reported, and can be relevant for cancer. To study methylation patterns around DSB after NHEJ and MMEJ repair, we used targeted bisulfite-sequencing (BS-seq) to quantify methylation of dozens of single cell clones after induction of DSB by CRISPR. Each single cell clone was classified according to the sequence signature to a specific repair mechanism: NHEJ or MMEJ. Comparison of single cell clones after DSB to control cells, without DSB, demonstrated correct restoration of the methylation levels. No difference in methylation patterns was noticed when comparing NHEJ to MMEJ. Methylation levels in gene body, highly methylated CpGs (n=61, 4000 base pairs around DSB) and in low methylation CpGs (n=19), remained stable after both MMEJ and NHEJ. Gene body methylation persisted even on the background of DNMT3A R882C mutation, the most prevalent preleukemic mutation, in which the de novo methylation machinery is compromised. An exception observed in a single CpG site (ASXL1 995) which demonstrated elevated methylation rate after DSB repair only in the presence of WT DNMT3A. In summary, DNA methylation restoration demonstrated high fidelity after DSB both in methylated and unmethylated gene body, even in cases where DNA resections and deletions occurred.
2022-09-11 | E-MTAB-12037 | biostudies-arrayexpress
Project description:The DNA damage response (DDR) is the signaling cascade that recognizes DNA double-strand breaks (DSB) and promotes their resolution via the DNA repair pathways of Non-Homologous End Joining (NHEJ) or Homologous Recombination (HR). We and others have shown that DDR activation requires DROSHA. However, whether DROSHA exerts its functions by associating with damage sites, what controls its recruitment and how DROSHA influences DNA repair, remains poorly understood. Here we show that DROSHA associates to DSBs independently from transcription. Neither H2AX, nor ATM nor DNA-PK kinase activities are required for its recruitment to break site. Rather, DROSHA interacts with RAD50 and inhibition of MRN by Mirin treatment abolishes this interaction. MRN inactivation by RAD50 knockdown or mirin treatment prevents DROSHA recruitment to DSB and, as a consequence, also 53BP1 recruitment. During DNA repair, DROSHA inactivation reduces NHEJ and boosts HR frequency. Indeed, DROSHA knockdown also increase the association of downstream HR factors such as RAD51 to DNA ends. Overall, our results demonstrate that DROSHA is recruited at DSBs by the MRN complex and direct DNA repair toward NHEJ.
2021-03-15 | GSE166631 | GEO
Project description:DNA double-strand breaks (DSBs) are among the most deleterious types of DNA damages as they can lead to mutations and chromosomal rearrangements, which underlie cancer development and progression. Non-homologous end-joining (NHEJ) is the dominant pathway for the repair of DSBs in human cells, which involves the DNA binding proteins Ku70/Ku80. Other DNA binding proteins such as Zinc Finger (ZnF) domain-containing proteins have also been implicated in DNA repair. However, their role in NHEJ has remained elusive. Here we show that ZNF384, which is a member of the C2H2 family of ZnF proteins that binds DNA in vitro, is recruited to DSBs in vivo. ZNF384 recruitment requires the PARP/PAR-dependent expansion of damaged chromatin followed by binding of ZNF384 to the exposed DNA via its unique C2H2 motifs. Mass-spectrometry-based experiments revealed that ZNF384 interacts with the Ku70/Ku80 NHEJ complex via its N-terminus. This interaction promotes the assembly of Ku70/Ku80 at DBSs as revealed by fluorescence recovery after photobleaching and fluorescence correlation spectroscopy. By regulating Ku70/80 dynamics, ZNF384 facilitates the assembly of several downstream NHEJ factors (e.g. APLF and XRCC4) and repair by cNHEJ at DSBs. Altogether, our data suggest that ZNF384 acts as a ‘Ku-adaptor’ that binds to DSBs and Ku70/80 to facilitate their binding and the subsequent build-up of a functional cNHEJ repairosome at these lesions, high-lighting a role for ZNF384 in DSB repair and genome maintenance.
2021-11-15 | PXD020417 | Pride
Project description:DNA double strand breaks (DSBs) are a major source of mutations. Both non-homologous-end-joining (NHEJ) and microhomology-mediated-end-joining (MMEJ) DSB repair pathways are error prone and produce deletions, which can lead to cancer. DSBs also lead to epigenetic changes, including demethylation, which is involved in carcinogenesis. Of specific interest is the MMEJ repair pathway, as it requires methylation restoration around the break, as a result of the resection and formation of single stranded (ssDNA) intermediates. While, methylation patterns after homologous recombination (HR) have been partially studied, the methylation status after MMEJ and NHEJ remains poorly reported, and can be relevant for cancer. To study methylation patterns around DSB after NHEJ and MMEJ repair, we used targeted bisulfite-sequencing (BS-seq) to quantify methylation of dozens of single cell clones after induction of DSB by CRISPR. Each single cell clone was classified according to the sequence signature to a specific repair mechanism: NHEJ or MMEJ. Comparison of single cell clones after DSB to control cells, without DSB, demonstrated correct restoration of the methylation levels. No difference in methylation patterns was noticed when comparing NHEJ to MMEJ. Methylation levels in gene body, highly methylated CpGs (n=61, 4000 base pairs around DSB) and in low methylation CpGs (n=19), remained stable after both MMEJ and NHEJ. Gene body methylation persisted even on the background of DNMT3A R882C mutation, the most prevalent preleukemic mutation, in which the de novo methylation machinery is compromised. An exception observed in a single CpG site (ASXL1 995) which demonstrated elevated methylation rate after DSB repair only in the presence of WT DNMT3A. In summary, DNA methylation restoration demonstrated high fidelity after DSB both in methylated and unmethylated gene body, even in cases where DNA resections and deletions occurred.
2022-08-25 | E-MTAB-12061 | biostudies-arrayexpress
Project description:The DNA-PK complex is essential for non-homologous end-joining (NHEJ) to repair DNA double-strand breaks (DSB) in a template-independent way. The association of Ku70/80 with the DSB ends facilitates the formation of the DNA-PK holoenzyme. Many questions remain regarding the dynamics that DNA-PK is attached and stabilized at broken DNA ends. Here we revealed that PRRX1, a homeodomain containing protein, mediates chromatin localization and subsequent activation of the DNA-PK. PRRX1 oligomerizes to enable its simultaneous associations with both double-strand DNA and the SAP domain of Ku70, thereby enhancing Ku anchoring at DSBs to stabilize DNA-PK for efficient NHEJ repair. Low expression and pathogenic mutations of PRRX1 are associated with genomic instability and defective NHEJ repair. The peptide interfering PRRX1 oligomerization compromises NHEJ and hampers cell survival on irradiation. These findings deepen our understanding of how the NHEJ machinery is activated and have implications for optimizing cancer therapies.
2025-03-26 | GSE265857 | GEO
Project description:Mutations in the ATM tumor suppressor gene confer cellular hypersensitivity to various DNA-damaging chemotherapeutic agents. To explore genetic resistance mechanisms towards such drugs, we performed genome-wide CRISPR-Cas9 loss-of-function screens in cells treated with the DNA topoisomerase I poison topotecan. Our ensuing characterizations of hits established that loss of terminal components of the non-homologous end joining (NHEJ) machinery or components of the BRCA1-A complex specifically confer topotecan resistance to ATM-deficient cells. Our findings indicate that hypersensitivity of ATM-mutant cells to topotecan or the poly-(ADP-ribose) polymerase (PARP) inhibitor olaparib is due to delayed engagement of homologous recombination repair (HRR) at a subset of DNA-replication-fork associated single ended double-strand breaks (seDSBs), which allows non-homologous end joining (NHEJ) mediated repair, resulting in toxic chromosome fusions. Thus, restoration of legitimate repair in ATM-deficient cells – either by preventing the DNA ligation step of NHEJ or by enhancing HRR engagement by deregulating the BRCA1-A complex – markedly suppresses this toxicity. We conclude that the crucial role for ATM at seDSBs is to prevent toxic LIG4-mediated NHEJ at damaged replication forks. Furthermore, our observation that suppressor mutations in ATM-mutant backgrounds are fundamentally different to those that operate in BRCA1-mutant scenarios suggests new opportunities for patient stratification in the clinic, as well as additional therapeutic vulnerabilities that might be exploited in drug-resistant cancers.
2019-11-12 | PXD011108 | Pride
Project description:Classical non-homologous end-joining (C-NHEJ) is a major mammalian DNA double strand break (DSB) repair pathway. Core C-NHEJ factors, such as XRCC4, are required for joining DSB intermediates of the G1 phase-specific V(D)J recombination reaction in progenitor lymphocytes. Core factors also contribute to joining DSBs in cycling mature B-lineage cells, including DSBs generated during antibody class switch recombination (CSR) and DSBs generated by ionizing radiation (IR). The XLF C-NHEJ factor is dispensable for V(D)J recombination in normal cells, but, due to functional redundancy, is absolutely required for this process in cells deficient for the ATM DSB response factor. The recently identified PAralogue of XRCC4 and XLF (PAXX) factor has homology to these two proteins and variably contributes to IR-induced DSB repair in human and chicken cells. We now report that PAXX is dispensable for joining V(D)J recombination DSBs in G1-arrested mouse pro-B cell lines, dispensable for joining CSR-associated DSBs in a cycling mouse B cell line, and dispensable for normal IR-resistance in both G1-arrested and cycling pro-B lines. However, we find that combined deficiency for PAXX and XLF in G1-arrested pro-B lines abrogates DSB joining during V(D)J recombination and sensitizes the cells to IR exposure. Thus, PAXX provides core C-NHEJ factor-associated functions in the absence of XLF and vice versa in G1-arrested Pro-B cell lines. Finally, we also find that PAXX-deficiency has no impact on V(D)J recombination DSB joining in ATM-deficient pro-B lines. We discuss implications of these findings with respect to potential PAXX and XLF functions in C-NHEJ.
2016-08-19 | GSE84102 | GEO
Project description:In contrast to our extensive knowledge on covalent SUMO target proteins, we are limited in our understanding of proteins that bind SUMO family members in a non-covalent manner. We have identified interactors of different SUMO isoforms: monomeric SUMO1, monomeric SUMO2 or linear trimeric SUMO2 chains, using a mass spectrometry-based proteomics approach. We identified 382 proteins that bind to different SUMO isoforms mainly in a preferential manner. Interestingly, XRCC4 was the only DNA repair protein in our screen with a preference for SUMO2 trimers over mono-SUMO2 as well as the only protein in our screen that belongs to the Non-Homologous End Joining (NHEJ) DNA double-strand break repair pathway. A functional SIM in XRCC4 regulated its recruitment to local sites of DNA damage and its phosphorylation in S320 by DNA-PKcs. Combined, our data highlight the importance of non-covalent and covalent sumoylation for DNA double-strand break repair via the NHEJ pathway and provides a resource of SUMO isoform interactors.
2021-01-29 | PXD022924 | Pride