scholarly journals Alternative End-Joining and Classical Nonhomologous End-Joining Pathways Repair Different Types of Double-Strand Breaks during Class-Switch Recombination

2013 ◽  
Vol 191 (11) ◽  
pp. 5751-5763 ◽  
Author(s):  
Elena M. Cortizas ◽  
Astrid Zahn ◽  
Maurice E. Hajjar ◽  
Anne-Marie Patenaude ◽  
Javier M. Di Noia ◽  
...  
Keyword(s):  
Class Switch Recombination ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Strand Breaks ◽  
Class Switch ◽  
Different Types ◽  
Alternative End Joining

scholarly journals Involvement of Artemis in nonhomologous end-joining during immunoglobulin class switch recombination

2008 ◽  
Vol 205 (13) ◽  
pp. 3031-3040 ◽  
Author(s):  
Likun Du ◽  
Mirjam van der Burg ◽  
Sergey W. Popov ◽  
Ashwin Kotnis ◽  
Jacques J.M. van Dongen ◽  
...  
Keyword(s):  
Class Switch Recombination ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Igg Subclass ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Immunoglobulin Class ◽  
Class Switch ◽  
Human B Cells

DNA double-strand breaks (DSBs) introduced in the switch (S) regions are intermediates during immunoglobulin class switch recombination (CSR). These breaks are subsequently recognized, processed, and joined, leading to recombination of the two S regions. Nonhomologous end-joining (NHEJ) is believed to be the principle mechanism involved in DSB repair during CSR. One important component in NHEJ, Artemis, has however been considered to be dispensable for efficient CSR. In this study, we have characterized the S recombinational junctions from Artemis-deficient human B cells. Sμ–Sα junctions could be amplified from all patients tested and were characterized by a complete lack of “direct” end-joining and a remarkable shift in the use of an alternative, microhomology-based end-joining pathway. Sμ–Sγ junctions could only be amplified from one patient who carries “hypomorphic” mutations. Although these Sμ–Sγ junctions appear to be normal, a significant increase of an unusual type of sequential switching from immunoglobulin (Ig)M, through one IgG subclass, to a different IgG subclass was observed, and the Sγ–Sγ junctions showed long microhomologies. Thus, when the function of Artemis is impaired, varying modes of CSR junction resolution may be used for different S regions. Our findings strongly link Artemis to the predominant NHEJ pathway during CSR.

scholarly journals 53BP1 is required for class switch recombination

2004 ◽  
Vol 165 (4) ◽  
pp. 459-464 ◽  
Author(s):  
Irene M. Ward ◽  
Bernardo Reina-San-Martin ◽  
Alexandru Olaru ◽  
Kay Minn ◽  
Koji Tamada ◽  
...  
Keyword(s):  
Class Switch Recombination ◽  
Cell Cycle Checkpoint ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Checkpoint Control ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Class Switch ◽  
Cycle Checkpoint

53BP1 participates early in the DNA damage response and is involved in cell cycle checkpoint control. Moreover, the phenotype of mice and cells deficient in 53BP1 suggests a defect in DNA repair (Ward et al., 2003b). Therefore, we asked whether or not 53BP1 would be required for the efficient repair of DNA double strand breaks. Our data indicate that homologous recombination by gene conversion does not depend on 53BP1. Moreover, 53BP1-deficient mice support normal V(D)J recombination, indicating that 53BP1 is not required for “classic” nonhomologous end joining. However, class switch recombination is severely impaired in the absence of 53BP1, suggesting that 53BP1 facilitates DNA end joining in a way that is not required or redundant for the efficient closing of RAG-induced strand breaks. These findings are similar to those observed in mice or cells deficient in the tumor suppressors ATM and H2AX, further suggesting that the functions of ATM, H2AX, and 53BP1 are closely linked.

scholarly journals Alternative end-joining catalyzes class switch recombination in the absence of both Ku70 and DNA ligase 4

2010 ◽  
Vol 207 (2) ◽  
pp. 417-427 ◽  
Author(s):  
Cristian Boboila ◽  
Catherine Yan ◽  
Duane R. Wesemann ◽  
Mila Jankovic ◽  
Jing H. Wang ◽  
...  
Keyword(s):  
B Cells ◽  
Class Switch Recombination ◽  
Strand Break ◽  
Nonhomologous End Joining ◽  
Dna Ligase ◽  
End Joining ◽  
Dsb Repair ◽  
Class Switch ◽  
Dna Double Strand Break ◽  
Alternative End Joining

The classical nonhomologous end-joining (C-NHEJ) DNA double-strand break (DSB) repair pathway employs the Ku70/80 complex (Ku) for DSB recognition and the XRCC4/DNA ligase 4 (Lig4) complex for ligation. During IgH class switch recombination (CSR) in B lymphocytes, switch (S) region DSBs are joined by C-NHEJ to form junctions either with short microhomologies (MHs; “MH-mediated” joins) or no homologies (“direct” joins). In the absence of XRCC4 or Lig4, substantial CSR occurs via “alternative” end-joining (A-EJ) that generates largely MH-mediated joins. Because upstream C-NHEJ components remain in XRCC4- or Lig4-deficient B cells, residual CSR might be catalyzed by C-NHEJ using a different ligase. To address this, we have assayed for CSR in B cells deficient for Ku70, Ku80, or both Ku70 and Lig4. Ku70- or Ku80-deficient B cells have reduced, but still substantial, CSR. Strikingly, B cells deficient for both Ku plus Lig4 undergo CSR similarly to Ku-deficient B cells, firmly demonstrating that an A-EJ pathway distinct from C-NHEJ can catalyze CSR end-joining. Ku-deficient or Ku- plus Lig4-deficient B cells are also biased toward MH-mediated CSR joins; but, in contrast to XRCC4- or Lig4-deficient B cells, generate substantial numbers of direct CSR joins. Our findings suggest that more than one form of A-EJ can function in CSR.

scholarly journals Role of PRKDC in cancer initiation, progression, and treatment

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yu Chen ◽  
Yi Li ◽  
Jiani Xiong ◽  
Bin Lan ◽  
Xuefeng Wang ◽  
...  
Keyword(s):  
Checkpoint Inhibitors ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Cancer Initiation ◽  
Different Types ◽  
Dependent Protein

AbstractThe PRKDC gene encodes the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) protein. DNA-PKcs plays an important role in nonhomologous end joining (NHEJ) of DNA double-strand breaks (DSBs) and is also closely related to the establishment of central immune tolerance and the maintenance of chromosome stability. The occurrence and development of different types of tumors and the results of their treatment are also influenced by DNA-PKcs, and it may also predict the results of radiotherapy, chemotherapy, and therapy with immune checkpoint inhibitors (ICIs). Here, we discuss and review the structure and mechanism of action of PRKDC and DNA-PKcs and their relationship with cancer.

scholarly journals Altered kinetics of nonhomologous end joining and class switch recombination in ligase IV–deficient B cells

2008 ◽  
Vol 205 (12) ◽  
pp. 2745-2753 ◽  
Author(s):  
Li Han ◽  
Kefei Yu
Keyword(s):  
Class Switch Recombination ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Class Switch ◽  
Ligase Iv ◽  
Switch Regions ◽  
Cytokine Stimulation

Immunoglobulin heavy chain class switch recombination (CSR) is believed to occur through the generation and repair of DNA double-strand breaks (DSBs) in the long and repetitive switch regions. Although implied, the role of the major vertebrate DSB repair pathway, nonhomologous end joining (NHEJ), in CSR has been controversial. By somatic gene targeting of DNA ligase IV (Lig4; a key component of NHEJ) in a B cell line (CH12F3) capable of highly efficient CSR in vitro, we found that NHEJ is required for efficient CSR. Disruption of the Lig4 gene in CH12F3 cells severely inhibits the initial rate of CSR and causes a late cell proliferation defect under cytokine stimulation. However, unlike V(D)J recombination, which absolutely requires NHEJ, CSR accumulates to a substantial level in Lig4-null cells. The data revealed a fast-acting NHEJ and a slow-acting alterative end joining of switch region breaks during CSR.

scholarly journals Oncogenic transformation in the absence of Xrcc4 targets peripheral B cells that have undergone editing and switching

2008 ◽  
Vol 205 (13) ◽  
pp. 3079-3090 ◽  
Author(s):  
Jing H. Wang ◽  
Frederick W. Alt ◽  
Monica Gostissa ◽  
Abhishek Datta ◽  
Michael Murphy ◽  
...  
Keyword(s):  
B Cells ◽  
Chromosomal Translocation ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Class Switch ◽  
Ig Heavy Chain ◽  
Peripheral B Cells

Nonhomologous end-joining (NHEJ) repairs DNA double-strand breaks (DSBs) during V(D)J recombination in developing lymphocytes and during immunoglobulin (Ig) heavy chain (IgH) class switch recombination (CSR) in peripheral B lymphocytes. We now show that CD21-cre–mediated deletion of the Xrcc4 NHEJ gene in p53-deficient peripheral B cells leads to recurrent surface Ig-negative B lymphomas (“CXP lymphomas”). Remarkably, CXP lymphomas arise from peripheral B cells that had attempted both receptor editing (secondary V[D]J recombination of Igκ and Igλ light chain genes) and IgH CSR subsequent to Xrcc4 deletion. Correspondingly, CXP tumors frequently harbored a CSR-based reciprocal chromosomal translocation that fused IgH to c-myc, as well as large chromosomal deletions or translocations involving Igκ or Igλ, with the latter fusing Igλ to oncogenes or to IgH. Our findings reveal peripheral B cells that have undergone both editing and CSR and show them to be common progenitors of CXP tumors. Our studies also reveal developmental stage-specific mechanisms of c-myc activation via IgH locus translocations. Thus, Xrcc4/p53-deficient pro–B lymphomas routinely activate c-myc by gene amplification, whereas Xrcc4/p53-deficient peripheral B cell lymphomas routinely ectopically activate a single c-myc copy.

scholarly journals Parp3 promotes long-range end-joining in murine cells

2018 ◽  
Author(s):  
Jacob V. Layer ◽  
J. Patrick Cleary ◽  
Alexander J. Brown ◽  
Kristen E. Stevenson ◽  
Sara N. Morrow ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Embryonic Stem ◽  
Cell Types ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Class Switch

AbstractChromosomal rearrangements, including translocations, are early and essential events in the formation of many tumors. Previous studies that defined the genetic requirements for rearrangement formation have identified differences between murine and human cells, most notably in the role of classical‐ and alternative-nonhomologous end joining factors (NHEJ). We reported that poly(ADP)ribose polymerase 3 (PARP3) promotes chromosomal rearrangements induced by endonucleases in multiple human cell types. In contrast to c-NHEJ factors, we show here that Parp3 also promotes rearrangements in murine cells, including translocations in murine embryonic stem cells (mESCs), class switch recombination in primary B cells and inversions in tail fibroblasts that generate Eml4-Alk fusions. In mESCs, Parp3-deficient cells had shorter deletion lengths at translocation junctions. This was corroborated using next-generation sequencing of Eml4-Alk junctions in tail fibroblasts and is consistent with a role for Parp3 in promoting the processing of DNA double-strand breaks. We confirmed a previous report that Parp1 also promotes rearrangement formation. In contrast with Parp3, rearrangement junctions in the absence of Parp1 had longer deletion lengths, suggesting Parp1 may suppress DSB processing. Together, these data indicate that Parp3 and Parp1 promote rearrangements with distinct phenotypes.

scholarly journals Redundant function of DNA ligase 1 and 3 in alternative end-joining during immunoglobulin class switch recombination

2016 ◽  
Vol 113 (5) ◽  
pp. 1261-1266 ◽  
Author(s):  
Shahnaz Masani ◽  
Li Han ◽  
Katheryn Meek ◽  
Kefei Yu
Keyword(s):  
Class Switch Recombination ◽  
Strand Break ◽  
Nonhomologous End Joining ◽  
Dna Ligase ◽  
End Joining ◽  
Dna Ligases ◽  
Class Switch ◽  
Dna Double Strand Break ◽  
Absolute Requirement ◽  
Alternative End Joining

Nonhomologous end-joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammals and resolves the DSBs generated during both V(D)J recombination in developing lymphocytes and class switch recombination (CSR) in antigen-stimulated B cells. In contrast to the absolute requirement for NHEJ to resolve DSBs associated with V(D)J recombination, DSBs associated with CSR can be resolved in NHEJ-deficient cells (albeit at a reduced level) by a poorly defined alternative end-joining (A-EJ) pathway. Deletion of DNA ligase IV (Lig4), a core component of the NHEJ pathway, reduces CSR efficiency in a mouse B-cell line capable of robust cytokine-stimulated CSR in cell culture. Here, we report that CSR levels are not further reduced by deletion of either of the two remaining DNA ligases (Lig1 and nuclear Lig3) in Lig4−/− cells. We conclude that in the absence of Lig4, Lig1, and Lig3 function in a redundant manner in resolving switch region DSBs during CSR.

Role for Artemis nuclease in the repair of radiation-induced DNA double strand breaks by alternative end joining

DNA Repair ◽  
2015 ◽  
Vol 31 ◽  
pp. 29-40 ◽  
Author(s):  
Mario Moscariello ◽  
Radi Wieloch ◽  
Aya Kurosawa ◽  
Fanghua Li ◽  
Noritaka Adachi ◽  
...  
Keyword(s):  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Alternative End Joining ◽  
Radiation Induced
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