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Cisneros-Aguirre M, Lopezcolorado FW, Ping X, Chen R, Stark JM. Distinct functions of PAXX and MRI during chromosomal end joining. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.21.607864. [PMID: 39229097 PMCID: PMC11370355 DOI: 10.1101/2024.08.21.607864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
A key step of Canonical Nonhomologous End Joining (C-NHEJ) is synapsis of DNA double strand break (DSB) ends for ligation. The DNA-PKcs dimer mediates synapsis in a long-range complex with DSB ends remaining apart, whereas the XLF homodimer can mediate synapsis in both long-range and short-range complexes. Recent structural studies found the PAXX homodimer may also facilitate synapsis in long-range complexes with DNA-PKcs via its interactions with Ku70. Thus, we examined the influence of PAXX in C-NHEJ of chromosomal DSBs, which we compared to another Ku-binding factor, MRI. Using EJ of blunt DSBs with Cas9 reporters as a readout for C-NHEJ, we found that PAXX and/or MRI are dispensable. However, when combined with disruption of DNA-PKcs, particularly with DNA-PKcs kinase inhibition, PAXX becomes important for blunt DSB EJ. In contrast, while DNA-PKcs is also important to suppress short deletion mutations with microhomology, this effect is not magnified with PAXX loss. MRI loss had no effect combined with DNA-PKcs disruption, but becomes important for blunt DSB EJ when combined with disruption of XLF, as is PAXX. Finally, XLF loss causes an increase in larger deletions compared to DNA-PKcs inhibition, which is magnified with combined loss of MRI. Altogether, we suggest that PAXX promotes DSB end synapsis during C-NHEJ in a manner that is partially redundant with DNA-PKcs and XLF, whereas MRI appears to be mainly important in the context of XLF disruption.
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Affiliation(s)
- Metztli Cisneros-Aguirre
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Felicia Wednesday Lopezcolorado
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Xiaoli Ping
- Department of Diabetes Complications & Metabolism, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Ruby Chen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
| | - Jeremy M Stark
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, 1500 E Duarte Rd., Duarte, CA 91010 USA
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2
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Yuanyuan J, Xinqiang Y. Micropeptides Identified from Human Genomes. J Proteome Res 2022; 21:865-873. [DOI: 10.1021/acs.jproteome.1c00889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jing Yuanyuan
- School of Public Health, North Sichuan Medical College, Nanchong 637000, China
| | - Yin Xinqiang
- School of Basic Medicine and Forensics, North Sichuan Medical College, Nanchong 637000, China
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3
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Acetyltransferases GCN5 and PCAF Are Required for B Lymphocyte Maturation in Mice. Biomolecules 2021; 12:biom12010061. [PMID: 35053209 PMCID: PMC8773862 DOI: 10.3390/biom12010061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 12/28/2021] [Accepted: 12/30/2021] [Indexed: 01/28/2023] Open
Abstract
B lymphocyte development has two DNA recombination processes: V(D)J recombination of the immunoglobulin (Igh) gene variable region, and class switching of the Igh constant regions from IgM to IgG, IgA, or IgE. V(D)J recombination is required for the successful maturation of B cells from pro-B to pre-B to immature-B and then to mature B cells in the bone marrow. CSR occurs outside of the bone marrow when mature B cells migrate to peripheral lymphoid organs, such as spleen and lymph nodes. Both V(D)J recombination and CSR depend on an open chromatin state that makes DNA accessible to specific enzymes, recombination activating gene (RAG), and activation-induced cytidine deaminase (AID). Acetyltransferases GCN5 and PCAF possess redundant functions acetylating histone H3 lysine 9 (H3K9). Here, we generated a mouse model that lacked both GCN5 and PCAF in B cells. Double-deficient mice possessed low levels of mature B cells in the bone marrow and peripheral organs, an accumulation of pro-B cells in bone marrow, and reduced CSR levels. We concluded that both GCN5 and PCAF are required for B-cell development in vivo.
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4
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Ghosh D, Raghavan SC. Nonhomologous end joining: new accessory factors fine tune the machinery. Trends Genet 2021; 37:582-599. [PMID: 33785198 DOI: 10.1016/j.tig.2021.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/08/2023]
Abstract
Nonhomologous DNA end joining (NHEJ) is one of the major DNA double-strand break (DSB) repair pathways in eukaryotes. The well-known critical proteins involved in NHEJ include Ku70/80, DNA-PKcs, Artemis, DNA pol λ/μ, DNA ligase IV-XRCC4, and XLF. Recent studies have added a number of new proteins to the NHEJ repertoire namely paralog of XRCC4 and XLF (PAXX), modulator of retroviral infection (MRI)/ cell cycle regulator of NHEJ (CYREN), transactivation response DNA-binding protein (TARDBP) of 43 kDa (TDP-43), intermediate filament family orphan (IFFO1), ERCC excision repair 6 like 2 (ERCC6L2), and RNase H2. PAXX acts as a stabilizing factor for the main NHEJ components. MRI/CYREN seems to play a dual role stimulating NHEJ in the G1 phase of the cell cycle, while inhibiting the pathway in the S and G2 phases. TDP-43 can recruit the ligase IV-XRCC4 complex to the DSB sites and stimulate ligation in neuronal cells. RNase H2 excises out the ribonucleotides inserted during repair by DNA polymerase μ/TdT. This review provides a brief glimpse into how these new partners were discovered and their contribution to the mechanism and regulation of NHEJ.
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Affiliation(s)
- Dipayan Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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5
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Oksenych V, Kainov DE. DNA Damage Response. Biomolecules 2021; 11:biom11010123. [PMID: 33477863 PMCID: PMC7832852 DOI: 10.3390/biom11010123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/14/2021] [Indexed: 11/16/2022] Open
Abstract
DNA in our cells is constantly modified by internal and external factors [...].
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Affiliation(s)
- Valentyn Oksenych
- Department for Cancer Research and Molecular Medicine (IKOM), Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Department of Biosciences and Nutrition (BioNuT), Karolinska Institutet, 14183 Huddinge, Sweden
- KG Jebsen Centre for B Cell Malignancies, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Correspondence: (V.O.); (D.E.K.)
| | - Denis E. Kainov
- Department for Cancer Research and Molecular Medicine (IKOM), Norwegian University of Science and Technology, 7491 Trondheim, Norway
- Institute of Technology, University of Tartu, 50090 Tartu, Estonia
- Correspondence: (V.O.); (D.E.K.)
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6
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Gago-Fuentes R, Oksenych V. Non-Homologous End Joining Factors XLF, PAXX and DNA-PKcs Maintain the Neural Stem and Progenitor Cell Population. Biomolecules 2020; 11:biom11010020. [PMID: 33379193 PMCID: PMC7823790 DOI: 10.3390/biom11010020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 12/19/2020] [Accepted: 12/23/2020] [Indexed: 12/26/2022] Open
Abstract
Non-homologous end-joining (NHEJ) is a major DNA repair pathway in mammalian cells that recognizes, processes and fixes DNA damage throughout the cell cycle and is specifically important for homeostasis of post-mitotic neurons and developing lymphocytes. Neuronal apoptosis increases in the mice lacking NHEJ factors Ku70 and Ku80. Inactivation of other NHEJ genes, either Xrcc4 or Lig4, leads to massive neuronal apoptosis in the central nervous system (CNS) that correlates with embryonic lethality in mice. Inactivation of either Paxx, Mri or Dna-pkcs NHEJ gene results in normal CNS development due to compensatory effects of Xlf. Combined inactivation of Xlf/Paxx, Xlf/Mri and Xlf/Dna-pkcs, however, results in late embryonic lethality and high levels of apoptosis in CNS. To determine the impact of NHEJ factors on the early stages of neurodevelopment, we isolated neural stem and progenitor cells from mouse embryos and investigated proliferation, self-renewal and differentiation capacity of these cells lacking either Xlf, Paxx, Dna-pkcs, Xlf/Paxx or Xlf/Dna-pkcs. We found that XRCC4-like factor (XLF), DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and paralogue of XRCC4 and XLF (PAXX) maintain the neural stem and progenitor cell populations and neurodevelopment in mammals, which is particularly evident in the double knockout models.
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Affiliation(s)
- Raquel Gago-Fuentes
- Department for Cancer Research and Molecular Medicine (IKOM), Norwegian University of Science and Technology, 7491 Trondheim, Norway;
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Valentyn Oksenych
- Department for Cancer Research and Molecular Medicine (IKOM), Norwegian University of Science and Technology, 7491 Trondheim, Norway;
- KG Jebsen Centre for B Cell Malignancies, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Correspondence:
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Castañeda-Zegarra S, Zhang Q, Alirezaylavasani A, Fernandez-Berrocal M, Yao R, Oksenych V. Leaky severe combined immunodeficiency in mice lacking non-homologous end joining factors XLF and MRI. Aging (Albany NY) 2020; 12:23578-23597. [PMID: 33289702 PMCID: PMC7762521 DOI: 10.18632/aging.202346] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/21/2020] [Indexed: 11/25/2022]
Abstract
Non-homologous end-joining (NHEJ) is a DNA repair pathway required to detect, process, and ligate DNA double-stranded breaks (DSBs) throughout the cell cycle. The NHEJ pathway is necessary for V(D)J recombination in developing B and T lymphocytes. During NHEJ, Ku70 and Ku80 form a heterodimer that recognizes DSBs and promotes recruitment and function of downstream factors PAXX, MRI, DNA-PKcs, Artemis, XLF, XRCC4, and LIG4. Mutations in several known NHEJ genes result in severe combined immunodeficiency (SCID). Inactivation of Mri, Paxx or Xlf in mice results in normal or mild phenotype, while combined inactivation of Xlf/Mri, Xlf/Paxx, or Xlf/Dna-pkcs leads to late embryonic lethality. Here, we describe three new mouse models. We demonstrate that deletion of Trp53 rescues embryonic lethality in mice with combined deficiencies of Xlf and Mri. Furthermore, Xlf-/-Mri-/-Trp53+/- and Xlf-/-Paxx-/-Trp53+/- mice possess reduced body weight, severely reduced mature lymphocyte counts, and accumulation of progenitor B cells. We also report that combined inactivation of Mri/Paxx results in live-born mice with modest phenotype, and combined inactivation of Mri/Dna-pkcs results in embryonic lethality. Therefore, we conclude that XLF is functionally redundant with MRI and PAXX during lymphocyte development in vivo. Moreover, Mri genetically interacts with Dna-pkcs and Paxx.
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Affiliation(s)
- Sergio Castañeda-Zegarra
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Qindong Zhang
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,Department of Cancer Immunology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Amin Alirezaylavasani
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway
| | - Marion Fernandez-Berrocal
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway
| | - Rouan Yao
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway
| | - Valentyn Oksenych
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,Department of Biosciences and Nutrition (BioNut), Karolinska Institutet, Huddinge, Sweden.,Institute of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
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8
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The molecular basis and disease relevance of non-homologous DNA end joining. Nat Rev Mol Cell Biol 2020; 21:765-781. [PMID: 33077885 DOI: 10.1038/s41580-020-00297-8] [Citation(s) in RCA: 221] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2020] [Indexed: 12/26/2022]
Abstract
Non-homologous DNA end joining (NHEJ) is the predominant repair mechanism of any type of DNA double-strand break (DSB) during most of the cell cycle and is essential for the development of antigen receptors. Defects in NHEJ result in sensitivity to ionizing radiation and loss of lymphocytes. The most critical step of NHEJ is synapsis, or the juxtaposition of the two DNA ends of a DSB, because all subsequent steps rely on it. Recent findings show that, like the end processing step, synapsis can be achieved through several mechanisms. In this Review, we first discuss repair pathway choice between NHEJ and other DSB repair pathways. We then integrate recent insights into the mechanisms of NHEJ synapsis with updates on other steps of NHEJ, such as DNA end processing and ligation. Finally, we discuss NHEJ-related human diseases, including inherited disorders and neoplasia, which arise from rare failures at different NHEJ steps.
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9
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Castañeda-Zegarra S, Fernandez-Berrocal M, Tkachov M, Yao R, Upfold NLE, Oksenych V. Genetic interaction between the non-homologous end-joining factors during B and T lymphocyte development: In vivo mouse models. Scand J Immunol 2020; 92:e12936. [PMID: 32654175 DOI: 10.1111/sji.12936] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/07/2020] [Accepted: 07/06/2020] [Indexed: 12/16/2022]
Abstract
Non-homologous end joining (NHEJ) is the main DNA repair mechanism for the repair of double-strand breaks (DSBs) throughout the course of the cell cycle. DSBs are generated in developing B and T lymphocytes during V(D)J recombination to increase the repertoire of B and T cell receptors. DSBs are also generated during the class switch recombination (CSR) process in mature B lymphocytes, providing distinct effector functions of antibody heavy chain constant regions. Thus, NHEJ is important for both V(D)J recombination and CSR. NHEJ comprises core Ku70 and Ku80 subunits that form the Ku heterodimer, which binds DSBs and promotes the recruitment of accessory factors (e.g., DNA-PKcs, Artemis, PAXX, MRI) and downstream core factors (XLF, Lig4 and XRCC4). In recent decades, new NHEJ proteins have been reported, increasing complexity of this molecular pathway. Numerous in vivo mouse models have been generated and characterized to identify the interplay of NHEJ factors and their role in development of adaptive immune system. This review summarizes the currently available mouse models lacking one or several NHEJ factors, with a particular focus on early B cell development. We also underline genetic interactions and redundancy in the NHEJ pathway in mice.
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Affiliation(s)
- Sergio Castañeda-Zegarra
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway
| | - Marion Fernandez-Berrocal
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway.,Behavioural Neurobiology MS Program, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Max Tkachov
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway
| | - Rouan Yao
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway
| | - Nikki Lyn Esnardo Upfold
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway
| | - Valentyn Oksenych
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology, Trondheim, Norway.,St. Olavs Hospital, Clinic of Medicine, Trondheim University Hospital, Trondheim, Norway.,Department of Biosciences and Nutrition (BioNut), Karolinska Institutet, Huddinge, Sweden.,Department of Clinical Medicine, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
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10
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Wang XS, Lee BJ, Zha S. The recent advances in non-homologous end-joining through the lens of lymphocyte development. DNA Repair (Amst) 2020; 94:102874. [PMID: 32623318 DOI: 10.1016/j.dnarep.2020.102874] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/16/2020] [Accepted: 05/24/2020] [Indexed: 12/17/2022]
Abstract
Lymphocyte development requires ordered assembly and subsequent modifications of the antigen receptor genes through V(D)J recombination and Immunoglobulin class switch recombination (CSR), respectively. While the programmed DNA cleavage events are initiated by lymphocyte-specific factors, the resulting DNA double-strand break (DSB) intermediates activate the ATM kinase-mediated DNA damage response (DDR) and rely on the ubiquitously expressed classical non-homologous end-joining (cNHEJ) pathway including the DNA-dependent protein kinase (DNA-PK), and, in the case of CSR, also the alternative end-joining (Alt-EJ) pathway, for repair. Correspondingly, patients and animal models with cNHEJ or DDR defects develop distinct types of immunodeficiency reflecting their specific DNA repair deficiency. The unique end-structure, sequence context, and cell cycle regulation of V(D)J recombination and CSR also provide a valuable platform to study the mechanisms of, and the interplay between, cNHEJ and DDR. Here, we compare and contrast the genetic consequences of DNA repair defects in V(D)J recombination and CSR with a focus on the newly discovered cNHEJ factors and the kinase-dependent structural roles of ATM and DNA-PK in animal models. Throughout, we try to highlight the pending questions and emerging differences that will extend our understanding of cNHEJ and DDR in the context of primary immunodeficiency and lymphoid malignancies.
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Affiliation(s)
- Xiaobin S Wang
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States; Graduate Program of Pathobiology and Molecular Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States
| | - Brian J Lee
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States
| | - Shan Zha
- Institute for Cancer Genetics, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States; Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States; Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States; Department of Immunology and Microbiology, Vagelos College of Physicians and Surgeons, Columbia University, New York City, NY 10032, United States.
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11
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Beck C, Castañeda-Zegarra S, Huse C, Xing M, Oksenych V. Mediator of DNA Damage Checkpoint Protein 1 Facilitates V(D)J Recombination in Cells Lacking DNA Repair Factor XLF. Biomolecules 2019; 10:biom10010060. [PMID: 31905950 PMCID: PMC7023129 DOI: 10.3390/biom10010060] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/23/2019] [Accepted: 12/24/2019] [Indexed: 11/16/2022] Open
Abstract
DNA double-strand breaks (DSBs) trigger the Ataxia telangiectasia mutated (ATM)-dependent DNA damage response (DDR), which consists of histone H2AX, MDC1, RNF168, 53BP1, PTIP, RIF1, Rev7, and Shieldin. Early stages of B and T lymphocyte development are dependent on recombination activating gene (RAG)-induced DSBs that form the basis for further V(D)J recombination. Non-homologous end joining (NHEJ) pathway factors recognize, process, and ligate DSBs. Based on numerous loss-of-function studies, DDR factors were thought to be dispensable for the V(D)J recombination. In particular, mice lacking Mediator of DNA Damage Checkpoint Protein 1 (MDC1) possessed nearly wild-type levels of mature B and T lymphocytes in the spleen, thymus, and bone marrow. NHEJ factor XRCC4-like factor (XLF)/Cernunnos is functionally redundant with ATM, histone H2AX, and p53-binding protein 1 (53BP1) during the lymphocyte development in mice. Here, we genetically inactivated MDC1, XLF, or both MDC1 and XLF in murine vAbl pro-B cell lines and, using chromosomally integrated substrates, demonstrated that MDC1 stimulates the V(D)J recombination in cells lacking XLF. Moreover, combined inactivation of MDC1 and XLF in mice resulted in synthetic lethality. Together, these findings suggest that MDC1 and XLF are functionally redundant during the mouse development, in general, and the V(D)J recombination, in particular.
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Affiliation(s)
- Carole Beck
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
- St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway
| | - Sergio Castañeda-Zegarra
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
- St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway
| | - Camilla Huse
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
- St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway
| | - Mengtan Xing
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
- St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway
| | - Valentyn Oksenych
- Department of Clinical and Molecular Medicine (IKOM), Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
- St. Olavs Hospital, Trondheim University Hospital, Clinic of Medicine, Postboks 3250 Sluppen, 7006 Trondheim, Norway
- Department of Biosciences and Nutrition (BioNuT), Karolinska Institutet, 14183 Huddinge, Sweden
- Correspondence:
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