Ku70 and Ligase IV deficiencies reveal distinct alternative end-joining outcomes in G1-arrested progenitor B cells
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA681890 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR13177200_1.fastq.gz | Fastqsanger.gz | |||
| SRR13177200_2.fastq.gz | Fastqsanger.gz | |||
| SRR13177201_1.fastq.gz | Fastqsanger.gz | |||
| SRR13177201_2.fastq.gz | Fastqsanger.gz | |||
| SRR13177202_1.fastq.gz | Fastqsanger.gz |
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Project description:Classical nonhomologous end-joining (C-NHEJ) repairs DNA double-stranded breaks (DSBs) throughout interphase but is thought to predominate in G1-phase when homologous recombination is unavailable. Complexes containing the Ku70/80 ("Ku") and XRCC4/Ligase IV (Lig4) core C-NHEJ factors are required, respectively, for sensing and joining DSBs. While such factors are exclusively required for joining RAG1/2-initiated DSBs during V(D)J recombination in G1-phase lymphocyte progenitors, cycling cells deficient for core C-NHEJ factors join chromosomal DSBs by alternative end-joining (A-EJ) pathways. Restriction of V(D)J recombination to C-NHEJ has been attributed to RAG-mediated exclusion of A-EJ; however, it remains unclear whether A-EJ is similarly excluded from more general DSBs in G1. Here, we report that Ku actively and robustly suppresses A-EJ of RAG1/2 and two classes of engineered endonuclease-mediated DSBs in G1-arrested progenitor B cell lines. Thus, while targeted DSBs remain as free broken ends in Lig4-deficient G1-arrested progenitor B cells, deletion of Ku70 in Lig4-deficient cells restores DSB rejoining and translocation to levels observed in Ku70-deficient counterparts. Correspondingly, while V(D)J recombination is abrogated in Ligase4-deficient lines, V(D)J-like joining occurs in Ku70-deficient and Ku70/Lig4 double-deficient lines through a translocation-based A-EJ mechanism. We conclude that in G1, Lig4-deficient progenitor B cells are functionally end-joining deficient due to a near complete Ku-dependent block in A-EJ. Thus, the differential impacts of Ku deficiency versus XRCC4/Ligase IV deficiency on V(D)J recombination, severity of neuronal apoptosis, and embryonic development, including Ku-deficiency rescuing Lig4-deficient embryonic lethality, may be explained by Ku-mediated inhibition of A-EJ in the G1 cell cycle phase.
2021-05-08 | GSE162453 | 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: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:Classical nonhomologous end joining (C-NHEJ) repairs DNA double-strand breaks (DSBs) throughout interphase but predominates in G1 phase when homologous recombination is unavailable. Complexes containing the Ku70/80 ("Ku") and XRCC4/ligase IV (Lig4) core C-NHEJ factors are required, respectively, for sensing and joining DSBs. While XRCC4/Lig4 are absolutely required for joining RAG1/2 endonuclease ("RAG")-initiated DSBs during V(D)J recombination in G1-phase progenitor lymphocytes, cycling cells deficient for XRCC4/Lig4 also can join chromosomal DSBs by alternative end-joining (A-EJ) pathways. Restriction of V(D)J recombination by XRCC4/Lig4-mediated joining has been attributed to RAG shepherding V(D)J DSBs exclusively into the C-NHEJ pathway. Here, we report that A-EJ of DSB ends generated by RAG1/2, Cas9:gRNA, and Zinc finger endonucleases in Lig4-deficient G1-arrested progenitor B cell lines is suppressed by Ku. Thus, while diverse DSBs remain largely as free broken ends in Lig4-deficient G1-arrested progenitor B cells, deletion of Ku70 increases DSB rejoining and translocation levels to those observed in Ku70-deficient counterparts. Correspondingly, while RAG-initiated V(D)J DSB joining is abrogated in Lig4-deficient G1-arrested progenitor B cell lines, joining of RAG-generated DSBs in Ku70-deficient and Ku70/Lig4 double-deficient lines occurs through a translocation-like A-EJ mechanism. Thus, in G1-arrested, Lig4-deficient progenitor B cells are functionally end-joining suppressed due to Ku-dependent blockage of A-EJ, potentially in association with G1-phase down-regulation of Lig1. Finally, we suggest that differential impacts of Ku deficiency versus Lig4 deficiency on V(D)J recombination, neuronal apoptosis, and embryonic development results from Ku-mediated inhibition of A-EJ in the G1 cell cycle phase in Lig4-deficient developing lymphocyte and neuronal cells.
| S-EPMC8166026 | biostudies-literature
Project description:The critical role of the alternative end joining (AEJ) repair mechanism in V(D)J recombination for B and T lymphocyte development, particularly in the absence of the key non-homologous end joining (NHEJ) component Ku70, is not well understood. AEJ involves functionally redundant factors such as Parp1 vs Polθ and Lig3 vs Lig1, making it unclear which factors are responsible for repairing V(D)J recombination. Additionally, the regulatory mechanism of AEJ remains enigmatic. In this study, we utilized the murine Igκ antigen locus as a model and employed gene editing and HTGTS-Seq pipelines to systematically evaluate potential factors involved in V(D)J recombination. We assessed various aspects of recombination, including efficiency, V gene usage, end resection, joining fidelity, repair patterns, and inter-chromosome translocation. Our findings highlight the Parp1-XRCC1-Lig3 axis as a key mediator of V(D)J recombination, regulated by 53BP1 and ATM. This study advances our understanding of AEJ in DNA damage repair and contributes to our knowledge of lymphocyte development in immunology.
2023-12-31 | GSE246239 | GEO
Project description:DNA-PK is a heterotrimeric complex that consists of Ku70 (XRCC6), Ku80 (XRCC5) and DNA-PKcs (PRKDC) subunits. DNA-PK complex is a major player in DNA double strand break (DSB) repair via non-homologous end joining pathway. This process requires all of DNA-PK subunits. Ku70/Ku80 heterodimers firstly bind to DNA-ends at DSB, that increase affinity of DNA-PKcs to DNA-ends. Recruitment of DNA-PKcs subunit to DSB leads to phosphorylation events near DSB, recruitment of another NHEJ-related genes that restore DNA integrity. However, today a lot of evidence demonstrate participation of DNA-PK components in other cellular process, e.g. cytosolic DNA sensing, apoptosis regulation, cellular movement and adhesion. It is important to note that not all subunits of DNA-PK complex are necessary for these process. This demonstrate the independent functions of DNA-PK subunits. Here we for the first time using NGS-sequencing analyzed the transcriptional changes in HEK293T cells under depletion of Ku70, Ku80 or DNA-PKcs to characterize the independent functions of each subunit.
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2012-12-31 | E-MTAB-940 | biostudies-arrayexpress
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2018-01-08 | GSE106922 | GEO
Project description:Targeting an engineered DNA fragment to a specific site in chromosomes in order to disrupt, overexpress or modify the nucleotide sequence of a gene requires homologous recombination repair mechanism. This DNA repair mechanism is not predominant in fungi, resulting in extremely low targeting efficiency. To increase this efficiency, it is becoming common practice to disable the non homologous end joining (NHEJ) pathway that causes random integration, by deleting homologous gene to human KU70 and KU80 which encode proteins functioning in the NHEJ pathway. These genes have been successfully deleted in several organisms, including the yeast Kluyveromyces lactis and the fungi Neurospora Crassa and several Aspergilli species. In this study we investigated the behavior of high penicillinG-producing Penicillium chrysogenum strains, in which the KU70 or KU80 homologues, HdfA or HdfB, had been deleted. Targeting efficiency in these mutant strains was significantly increased relative to the reference strain. Both physiological and transcriptome data of chemostat cultivations of the hdfA deletion strain and the reference strain showed minimal differences. However, in a direct competition experiment to assess global strain fitness, the reference strain had a clear advantage over the deletion strain. The full characterization of these recombinant host strains is an essential step to guide the future construction of a whole genome knock-out mutant collection.
2009-03-09 | GSE12893 | GEO
Project description:Glioblastoma (GBM) is a malignancy with a complex tumor microenvironment (TME) dominated by glioblastoma stem cells (GSCs) and infiltrated by tumor-associated macrophages (TAMs), and exhibits aberrant metabolic pathways. Lactate is a critical glycolytic metabolite that promotes tumor progression; however, the mechanisms of lactate transportation and lactylation in the tumor microenvironment (TME) of GBM remain elusive. Here, we found that the lactate metabolic signature was highly expressed in TAMs and tumor cells. Moreover, TAMs provide lactate to GSCs, promoting GSC proliferation and inducing lactylation of the non-homologous end joining (NHEJ) protein KU70 at the residue K317. TAM-derived lactate-mediated KU70 lactylation inhibits cGAS- type I interferon signaling, remodeling the immunosuppressive microenvironment through reduced cytotoxic CD8+ T cell infiltration, promoting the malignant progression of GBM. Combinatorial targeting of lactate transport and immune checkpoints demonstrated additive therapeutic benefit in immunocompetent orthotopic xenograft models. This study unveils TAM-derived lactate and lactylation as a critical regulator of NHEJ and create immunosuppressive microenvironment, linking the TME to DNA damage response in GBM and opening novel avenues for developing combinatorial therapy for GBM.
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