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Kumari N, Antil H, Kumari S, Raghavan SC. Deficiency of ligase IV leads to reduced NHEJ, accumulation of DNA damage, and can sensitize cells to cancer therapeutics. Genomics 2023; 115:110731. [PMID: 37871849 DOI: 10.1016/j.ygeno.2023.110731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/14/2023] [Accepted: 10/19/2023] [Indexed: 10/25/2023]
Abstract
Ligase IV is a key enzyme involved during DNA double-strand breaks (DSBs) repair through nonhomologous end joining (NHEJ). However, in contrast to Ligase IV deficient mouse cells, which are embryonic lethal, Ligase IV deficient human cells, including pre-B cells, are viable. Using CRISPR-Cas9 mediated genome editing, we have generated six different LIG4 mutants in cervical cancer and normal kidney epithelial cell lines. While the LIG4 mutant cells showed a significant reduction in NHEJ, joining mediated through microhomology-mediated end joining (MMEJ) and homologous recombination (HR) were significantly high. The reduced NHEJ joining activity was restored by adding purified Ligase IV/XRCC4. Accumulation of DSBs and reduced cell viability were observed in LIG4 mutant cells. LIG4 mutant cells exhibited enhanced sensitivity towards DSB-inducing agents such as ionizing radiation (IR) and etoposide. More importantly, the LIG4 mutant of cervical cancer cells showed increased sensitivity towards FDA approved drugs such as Carboplatin, Cisplatin, Paclitaxel, Doxorubicin, and Bleomycin used for cervical cancer treatment. These drugs, in combination with IR showed enhanced cancer cell death in the background of LIG4 gene mutation. Thus, our study reveals that mutation in LIG4 results in compromised NHEJ, leading to sensitization of cervical cancer cells towards currently used cancer therapeutics.
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Affiliation(s)
- Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Himanshu Antil
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Susmita Kumari
- 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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2
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Balducci E, Steimlé T, Smith C, Villarese P, Feroul M, Payet-Bornet D, Kaltenbach S, Couronné L, Lhermitte L, Touzart A, Dourthe ME, Simonin M, Baruchel A, Dombret H, Ifrah N, Boissel N, Nadel B, Macintyre E, Cieslak A, Asnafi V. TREC mediated oncogenesis in human immature T lymphoid malignancies preferentially involves ZFP36L2. Mol Cancer 2023; 22:108. [PMID: 37430263 DOI: 10.1186/s12943-023-01794-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/25/2023] [Indexed: 07/12/2023] Open
Abstract
The reintegration of excised signal joints resulting from human V(D)J recombination was described as a potent source of genomic instability in human lymphoid cancers. However, such molecular events have not been recurrently reported in clinical patient lymphoma/leukemia samples. Using a specifically designed NGS-capture pipeline, we here demonstrated the reintegration of T-cell receptor excision circles (TRECs) in 20/1533 (1.3%) patients with T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL). Remarkably, the reintegration of TREC recurrently targeted the tumor suppressor gene, ZFP36L2, in 17/20 samples. Thus, our data identified a new and hardly detectable mechanism of gene deregulation in lymphoid cancers providing new insights in human oncogenesis.
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Affiliation(s)
- Estelle Balducci
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Thomas Steimlé
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
- TAGC, UMR 1090, Aix-Marseille University, INSERM, Marseille, France
| | - Charlotte Smith
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Patrick Villarese
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Mélanie Feroul
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | | | - Sophie Kaltenbach
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Lucile Couronné
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Ludovic Lhermitte
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Aurore Touzart
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Marie-Emilie Dourthe
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Mathieu Simonin
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - André Baruchel
- Department of Pediatric Hematology and Immunology, University Hospital Robert Debré, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
- Institut Universitaire d'Hématologie, EA-3518, University Hospital Saint-Louis, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | - Hervé Dombret
- Université Paris Diderot, Institut Universitaire d'Hématologie, EA-3518, Assistance Publique-Hôpitaux de Paris, University Hospital Saint-Louis, 75010, Paris, France
| | - Norbert Ifrah
- PRES LUNAM, CHU Angers Service Des Maladies du Sang, INSERM U 892, 49933, Angers, France
| | - Nicolas Boissel
- Université Paris Diderot, Institut Universitaire d'Hématologie, EA-3518, Assistance Publique-Hôpitaux de Paris, University Hospital Saint-Louis, 75010, Paris, France
| | - Bertrand Nadel
- Aix Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Elizabeth Macintyre
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France
| | - Agata Cieslak
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France.
| | - Vahid Asnafi
- Laboratory of Onco-Hematology, Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
- Université Paris Cité, CNRS, INSERM U1151, Institut Necker Enfants Malades (INEM), Paris, France.
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3
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Chen W, Hu J, Huang J, Liu Q, Wang Q, Zhang Y, Yang D. Characterization of T-cell receptors and immunoglobulin heavy chains loci and identification of T/B cell clusters in teleost. FISH & SHELLFISH IMMUNOLOGY 2023; 136:108746. [PMID: 37054766 DOI: 10.1016/j.fsi.2023.108746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/09/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
Bacterial disease is one of the important factors leading to economic losses in the turbot (Scophthalmus maximus) cultivation industry. T lymphocytes are major components of cellular immunity, whereas B lymphocytes produce immunoglobulins (Ig) that are key elements of humoral immune responses against infection. However, the genomic organization of genes encoding T-cell receptors (TCR) and immunoglobulin heavy chains (IgHs) in turbot remains largely unknown. In this study, abundant full-length transcripts of TCRs and IgHs were sequenced by Isoform-sequencing (Iso-seq), and we investigated and annotated the V, D, J and C gene loci of TCRα, TCRβ, IgT, IgM and IgD in turbot. Furthermore, through single-cell RNA sequencing (scRNA-seq) of blood leukocytes, we confirmed that these identified TCRs and IgHs were highly expressed in T/B cell clusters, respectively. Meanwhile, we also identified the IgM+IgD+ B and IgT+ B cells with differential gene expression profiles and potential functions. Taken together, our results provide a comprehensive understanding of TCRs and IgHs loci in turbot, which will contribute to evolutionary and functional characterization of T and B lymphocytes in teleost.
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Affiliation(s)
- Weijie Chen
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China
| | - Jing Hu
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China
| | - Jianchang Huang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering, Laboratory for Aquatic Animal Diseases, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, 200237, China.
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López C, Burkhardt B, Chan JKC, Leoncini L, Mbulaiteye SM, Ogwang MD, Orem J, Rochford R, Roschewski M, Siebert R. Burkitt lymphoma. Nat Rev Dis Primers 2022; 8:78. [PMID: 36522349 DOI: 10.1038/s41572-022-00404-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/19/2022] [Indexed: 12/16/2022]
Abstract
Burkitt lymphoma (BL) is an aggressive form of B cell lymphoma that can affect children and adults. The study of BL led to the identification of the first recurrent chromosomal aberration in lymphoma, t(8;14)(q24;q32), and subsequent discovery of the central role of MYC and Epstein-Barr virus (EBV) in tumorigenesis. Most patients with BL are cured with chemotherapy but those with relapsed or refractory disease usually die of lymphoma. Historically, endemic BL, non-endemic sporadic BL and the immunodeficiency-associated BL have been recognized, but differentiation of these epidemiological variants is confounded by the frequency of EBV positivity. Subtyping into EBV+ and EBV- BL might better describe the biological heterogeneity of the disease. Phenotypically resembling germinal centre B cells, all types of BL are characterized by dysregulation of MYC due to enhancer activation via juxtaposition with one of the three immunoglobulin loci. Additional molecular changes commonly affect B cell receptor and sphingosine-1-phosphate signalling, proliferation, survival and SWI-SNF chromatin remodelling. BL is diagnosed on the basis of morphology and high expression of MYC. BL can be effectively treated in children and adolescents with short durations of high dose-intensity multiagent chemotherapy regimens. Adults are more susceptible to toxic effects but are effectively treated with chemotherapy, including modified versions of paediatric regimens. The outcomes in patients with BL are good in high-income countries with low mortality and few late effects, but in low-income and middle-income countries, BL is diagnosed late and is usually treated with less-effective regimens affecting the overall good outcomes in patients with this lymphoma.
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Affiliation(s)
- Cristina López
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Institute of Human Genetics, Ulm University and Ulm University Medical Center, Ulm, Germany
| | - Birgit Burkhardt
- Non-Hodgkin's Lymphoma Berlin-Frankfurt-Münster (NHL-BFM) Study Center and Paediatric Hematology, Oncology and BMT, University Hospital Muenster, Muenster, Germany
| | - John K C Chan
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong SAR, China
| | - Lorenzo Leoncini
- Section of Pathology, Department of Medical Biotechnology, University of Siena, Siena, Italy
| | - Sam M Mbulaiteye
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, US Department of Health and Human Services, Bethesda, MD, USA
| | | | | | - Rosemary Rochford
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Mark Roschewski
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Reiner Siebert
- Institute of Human Genetics, Ulm University and Ulm University Medical Center, Ulm, Germany.
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Paranjape AM, Desai SS, Nishana M, Roy U, Nilavar NM, Mondal A, Kumari R, Radha G, Katapadi VK, Choudhary B, Raghavan SC. Nonamer dependent RAG cleavage at CpGs can explain mechanism of chromosomal translocations associated to lymphoid cancers. PLoS Genet 2022; 18:e1010421. [PMID: 36228010 PMCID: PMC9595545 DOI: 10.1371/journal.pgen.1010421] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/25/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Chromosomal translocations are considered as one of the major causes of lymphoid cancers. RAG complex, which is responsible for V(D)J recombination, can also cleave non-B DNA structures and cryptic RSSs in the genome leading to chromosomal translocations. The mechanism and factors regulating the illegitimate function of RAGs resulting in oncogenesis are largely unknown. Upon in silico analysis of 3760 chromosomal translocations from lymphoid cancer patients, we find that 93% of the translocation breakpoints possess adjacent cryptic nonamers (RAG binding sequences), of which 77% had CpGs in proximity. As a proof of principle, we show that RAGs can efficiently bind to cryptic nonamers present at multiple fragile regions and cleave at adjacent mismatches generated to mimic the deamination of CpGs. ChIP studies reveal that RAGs can indeed recognize these fragile sites on a chromatin context inside the cell. Finally, we show that AID, the cytidine deaminase, plays a significant role during the generation of mismatches at CpGs and reconstitute the process of RAG-dependent generation of DNA breaks both in vitro and inside the cells. Thus, we propose a novel mechanism for generation of chromosomal translocation, where RAGs bind to the cryptic nonamer sequences and direct cleavage at adjacent mismatch generated due to deamination of meCpGs or cytosines.
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Affiliation(s)
- Amita M. Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sagar S. Desai
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Mayilaadumveettil Nishana
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Namrata M. Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Amrita Mondal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Gudapureddy Radha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- * E-mail: (BC); (SCR)
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- * E-mail: (BC); (SCR)
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Honkova K, Rossnerova A, Chvojkova I, Milcova A, Margaryan H, Pastorkova A, Ambroz A, Rossner P, Jirik V, Rubes J, Sram RJ, Topinka J. Genome-Wide DNA Methylation in Policemen Working in Cities Differing by Major Sources of Air Pollution. Int J Mol Sci 2022; 23:ijms23031666. [PMID: 35163587 PMCID: PMC8915177 DOI: 10.3390/ijms23031666] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
DNA methylation is the most studied epigenetic mechanism that regulates gene expression, and it can serve as a useful biomarker of prior environmental exposure and future health outcomes. This study focused on DNA methylation profiles in a human cohort, comprising 125 nonsmoking city policemen (sampled twice), living and working in three localities (Prague, Ostrava and Ceske Budejovice) of the Czech Republic, who spent the majority of their working time outdoors. The main characterization of the localities, differing by major sources of air pollution, was defined by the stationary air pollution monitoring of PM2.5, B[a]P and NO2. DNA methylation was analyzed by a genome-wide microarray method. No season-specific DNA methylation pattern was discovered; however, we identified 13,643 differentially methylated CpG loci (DML) for a comparison between the Prague and Ostrava groups. The most significant DML was cg10123377 (log2FC = −1.92, p = 8.30 × 10−4) and loci annotated to RPTOR (total 20 CpG loci). We also found two hypomethylated loci annotated to the DNA repair gene XRCC5. Groups of DML annotated to the same gene were linked to diabetes mellitus (KCNQ1), respiratory diseases (PTPRN2), the dopaminergic system of the brain and neurodegenerative diseases (NR4A2). The most significant possibly affected pathway was Axon guidance, with 86 potentially deregulated genes near DML. The cluster of gene sets that could be affected by DNA methylation in the Ostrava groups mainly includes the neuronal functions and biological processes of cell junctions and adhesion assembly. The study demonstrates that the differences in the type of air pollution between localities can affect a unique change in DNA methylation profiles across the human genome.
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Affiliation(s)
- Katerina Honkova
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
- Correspondence: ; Tel.: +420-775-406-170
| | - Andrea Rossnerova
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
| | - Irena Chvojkova
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
| | - Alena Milcova
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
| | - Hasmik Margaryan
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
| | - Anna Pastorkova
- Department of Nanotoxicology and Molecular Epidemiology, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.P.); (A.A.); (P.R.J.)
| | - Antonin Ambroz
- Department of Nanotoxicology and Molecular Epidemiology, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.P.); (A.A.); (P.R.J.)
| | - Pavel Rossner
- Department of Nanotoxicology and Molecular Epidemiology, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.P.); (A.A.); (P.R.J.)
| | - Vitezslav Jirik
- Centre for Epidemiological Research, Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic;
| | - Jiri Rubes
- Veterinary Research Institute, Hudcova 296/70, 621 00 Brno, Czech Republic;
| | - Radim J. Sram
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
| | - Jan Topinka
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine CAS, Videnska 1083, 142 20 Prague 4, Czech Republic; (A.R.); (I.C.); (A.M.); (H.M.); (R.J.S.); (J.T.)
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7
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Qian C, Li D, Chen Y. ETS factors in prostate cancer. Cancer Lett 2022; 530:181-189. [PMID: 35033589 PMCID: PMC8832285 DOI: 10.1016/j.canlet.2022.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/01/2022] [Accepted: 01/10/2022] [Indexed: 12/21/2022]
Abstract
The ETS family of proteins consists of 28 transcription factors, many of which play critical roles in both normal tissue development and homeostasis and have been implicated in development and progression of a variety of cancers. In prostate cancer, gene fusion and overexpression of ETS factors ERG, FLI1, ETV1, ETV4 and ETV5 have been found in half of prostate cancer patients in Caucasian men and define the largest genetic subtype of prostate cancer. This review summarizes the data on the discovery, modeling, molecular taxonomy, lineage plasticity and therapeutic targeting of ETS family members in prostate cancer.
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Affiliation(s)
- Cheng Qian
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA; Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, People's Republic of China
| | - Dan Li
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Yu Chen
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA; Department of Medicine, Memorial Sloan Kettering Cancer Center, NY, 10065, USA; Department of Medicine, Weill Cornell Medical College, New York, NY, 10065, USA.
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8
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Yang FY, Wei N, Zhang ZH, Wang M, Liu YC, Zhang LF, Gu F. Genome editing of Corynebacterium glutamicum mediated with Cpf1 plus Ku/LigD. Biotechnol Lett 2021; 43:2273-2281. [PMID: 34669078 DOI: 10.1007/s10529-021-03195-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/11/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Corynebacterium glutamicum (C. glutamicum) has been harnessed for multi-million-ton scale production of glutamate and lysine. To further increase its amino acid production for fermentation industry, there is an acute need to develop next-generation genome manipulation tool for its metabolic engineering. All reported methods for genome editing triggered with CRISPR-Cas are based on the homologous recombination. While, it requires the generation of DNA repair template, which is a bottle-neck for its extensive application. RESULTS In this study, we developed a method for gene knockout in C. glutamicum via CRISPR-Cpf1-coupled non-homologous end-joining (CC-NHEJ). Specifically, CRISPR-Cpf1 introduced double-strand breaks in the genome of C. glutamicum, which was further repaired by ectopically expressed two NHEJ key proteins (Mycobacterium tuberculosis Ku and ligase D). We provide the proof of concept, for CC-NHEJ, by the successful knockout of the crtYf/e gene in C. glutamicum with the efficiency of 22.00 ± 5.56%, or something like that. CONCLUSION The present study reported a novel genome manipulation method for C. glutamicum.
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Affiliation(s)
- Fa-Yu Yang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Nan Wei
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Zhi-Hao Zhang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Mi Wang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Ying-Chun Liu
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Li-Fang Zhang
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China
| | - Feng Gu
- Key Laboratory of Veterinary Chemical Drugs and Pharmaceutics, Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, China.
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9
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Yuan M, Wang Y, Qin M, Zhao X, Chen X, Li D, Miao Y, Otieno Odhiambo W, Liu H, Ma Y, Ji Y. RAG enhances BCR-ABL1-positive leukemic cell growth through its endonuclease activity in vitro and in vivo. Cancer Sci 2021; 112:2679-2691. [PMID: 33949040 PMCID: PMC8253288 DOI: 10.1111/cas.14939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/15/2021] [Accepted: 04/30/2021] [Indexed: 12/14/2022] Open
Abstract
BCR-ABL1 gene fusion associated with additional DNA lesions involves the pathogenesis of chronic myelogenous leukemia (CML) from a chronic phase (CP) to a blast crisis of B lymphoid (CML-LBC) lineage and BCR-ABL1+ acute lymphoblastic leukemia (BCR-ABL1+ ALL). The recombination-activating gene RAG1 and RAG2 (collectively, RAG) proteins that assemble a diverse set of antigen receptor genes during lymphocyte development are abnormally expressed in CML-LBC and BCR-ABL1+ ALL. However, the direct involvement of dysregulated RAG in disease progression remains unclear. Here, we generate human wild-type (WT) RAG and catalytically inactive RAG-expressing BCR-ABL1+ and BCR-ABL1- cell lines, respectively, and demonstrate that BCR-ABL1 specifically collaborates with RAG recombinase to promote cell survival in vitro and in xenograft mice models. WT RAG-expressing BCR-ABL1+ cell lines and primary CD34+ bone marrow cells from CML-LBC samples maintain more double-strand breaks (DSB) compared to catalytically inactive RAG-expressing BCR-ABL1+ cell lines and RAG-deficient CML-CP samples, which are measured by γ-H2AX. WT RAG-expressing BCR-ABL1+ cells are biased to repair RAG-mediated DSB by the alternative non-homologous end joining pathway (a-NHEJ), which could contribute genomic instability through increasing the expression of a-NHEJ-related MRE11 and RAD50 proteins. As a result, RAG-expressing BCR-ABL1+ cells decrease sensitivity to tyrosine kinase inhibitors (TKI) by activating BCR-ABL1 signaling but independent of the levels of BCR-ABL1 expression and mutations in the BCR-ABL1 tyrosine kinase domain. These findings identify a surprising and novel role of RAG in the functional specialization of disease progression in BCR-ABL1+ leukemia through its endonuclease activity.
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MESH Headings
- Acid Anhydride Hydrolases/metabolism
- Animals
- Blast Crisis/genetics
- Blast Crisis/metabolism
- Cell Line, Tumor
- Cell Proliferation
- Cell Survival
- DNA Breaks, Double-Stranded
- DNA End-Joining Repair
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Disease Progression
- Endonucleases/metabolism
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Genomic Instability
- Heterografts
- Histones/analysis
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- In Vitro Techniques
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- MRE11 Homologue Protein/metabolism
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Nuclear Proteins/deficiency
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism
- Protein Kinase Inhibitors/therapeutic use
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Affiliation(s)
- Meng Yuan
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Yang Wang
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Mengting Qin
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Xiaohui Zhao
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Xiaodong Chen
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Dandan Li
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Yinsha Miao
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
- Department of Clinical laboratoryXi’an No. 3 HospitalThe Affiliated Hospital of Northwest UniversityXi’anChina
| | - Wood Otieno Odhiambo
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Huasheng Liu
- Department of HematologyThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’anChina
| | - Yunfeng Ma
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
| | - Yanhong Ji
- Department of Pathogenic Biology and Immunology, School of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anChina
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10
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Ioniţă E, Marcu A, Temelie M, Savu D, Şerbănescu M, Ciubotaru M. Radiofrequency EMF irradiation effects on pre-B lymphocytes undergoing somatic recombination. Sci Rep 2021; 11:12651. [PMID: 34135382 PMCID: PMC8208969 DOI: 10.1038/s41598-021-91790-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/31/2021] [Indexed: 01/14/2023] Open
Abstract
Intense electromagnetic fields (EMFs) induce DNA double stranded breaks (DSBs) in exposed lymphocytes.We study developing pre-B lymphocytes following V(D)J recombination at their Immunoglobulin light chain loci (IgL). Recombination physiologically induces DNA DSBs, and we tested if low doses of EMF irradiation affect this developmental stage. Recombining pre-B cells, were exposed for 48 h to low intensity EMFs (maximal radiative power density flux S of 9.5 µW/cm2 and electric field intensity 3 V/m) from waves of frequencies ranging from 720 to 1224 MHz. Irradiated pre-B cells show decreased levels of recombination, reduction which is dependent upon the power dose and most remarkably upon the frequency of the applied EMF. Although 50% recombination reduction cannot be obtained even for an S of 9.5 µW/cm2 in cells irradiated at 720 MHz, such an effect is reached in cells exposed to only 0.45 µW/cm2 power with 950 and 1000 MHz waves. A maximal four-fold recombination reduction was measured in cells exposed to 1000 MHz waves with S from 0.2 to 4.5 µW/cm2 displaying normal levels of γH2AX phosphorylated histone. Our findings show that developing B cells exposure to low intensity EMFs can affect the levels of production and diversity of their antibodies repertoire.
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Affiliation(s)
- Elena Ioniţă
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania.,Department of Immunology, Internal Medicine, Colentina Clinical Hospital, 72202, Bucharest, Romania
| | - Aurelian Marcu
- Center for Advanced Laser Technologies, National Institute for Laser Plasma and Radiation Physics, 077125, Măgurele, Ilfov, Romania
| | - Mihaela Temelie
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania
| | - Diana Savu
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania
| | - Mihai Şerbănescu
- Center for Advanced Laser Technologies, National Institute for Laser Plasma and Radiation Physics, 077125, Măgurele, Ilfov, Romania
| | - Mihai Ciubotaru
- Department of Physics of Life and Environmental Sciences, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, 077125, Măgurele, Ilfov, Romania. .,Department of Immunology, Internal Medicine, Colentina Clinical Hospital, 72202, Bucharest, Romania.
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11
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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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12
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Kaeser G, Chun J. Brain cell somatic gene recombination and its phylogenetic foundations. J Biol Chem 2020; 295:12786-12795. [PMID: 32699111 PMCID: PMC7476723 DOI: 10.1074/jbc.rev120.009192] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 07/22/2020] [Indexed: 12/19/2022] Open
Abstract
A new form of somatic gene recombination (SGR) has been identified in the human brain that affects the Alzheimer's disease gene, amyloid precursor protein (APP). SGR occurs when a gene sequence is cut and recombined within a single cell's genomic DNA, generally independent of DNA replication and the cell cycle. The newly identified brain SGR produces genomic complementary DNAs (gencDNAs) lacking introns, which integrate into locations distinct from germline loci. This brief review will present an overview of likely related recombination mechanisms and genomic cDNA-like sequences that implicate evolutionary origins for brain SGR. Similarities and differences exist between brain SGR and VDJ recombination in the immune system, the first identified SGR form that now has a well-defined enzymatic machinery. Both require gene transcription, but brain SGR uses an RNA intermediate and reverse transcriptase (RT) activity, which are characteristics shared with endogenous retrotransposons. The identified gencDNAs have similarities to other cDNA-like sequences existing throughout phylogeny, including intron-less genes and inactive germline processed pseudogenes, with likely overlapping biosynthetic processes. gencDNAs arise somatically in an individual to produce multiple copies; can be functional; appear most frequently within postmitotic cells; have diverse sequences; change with age; and can change with disease state. Normally occurring brain SGR may represent a mechanism for gene optimization and long-term cellular memory, whereas its dysregulation could underlie multiple brain disorders and, potentially, other diseases like cancer. The involvement of RT activity implicates already Food and Drug Administration-approved RT inhibitors as possible near-term interventions for managing SGR-associated diseases and suggest next-generation therapeutics targeting SGR elements.
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Affiliation(s)
- Gwendolyn Kaeser
- Degenerative Disease Program at the Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Jerold Chun
- Degenerative Disease Program at the Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
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13
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Sproul JS, Khost DE, Eickbush DG, Negm S, Wei X, Wong I, Larracuente AM. Dynamic Evolution of Euchromatic Satellites on the X Chromosome in Drosophila melanogaster and the simulans Clade. Mol Biol Evol 2020; 37:2241-2256. [PMID: 32191304 PMCID: PMC7403614 DOI: 10.1093/molbev/msaa078] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Satellite DNAs (satDNAs) are among the most dynamically evolving components of eukaryotic genomes and play important roles in genome regulation, genome evolution, and speciation. Despite their abundance and functional impact, we know little about the evolutionary dynamics and molecular mechanisms that shape satDNA distributions in genomes. Here, we use high-quality genome assemblies to study the evolutionary dynamics of two complex satDNAs, Rsp-like and 1.688 g/cm3, in Drosophila melanogaster and its three nearest relatives in the simulans clade. We show that large blocks of these repeats are highly dynamic in the heterochromatin, where their genomic location varies across species. We discovered that small blocks of satDNA that are abundant in X chromosome euchromatin are similarly dynamic, with repeats changing in abundance, location, and composition among species. We detail the proliferation of a rare satellite (Rsp-like) across the X chromosome in D. simulans and D. mauritiana. Rsp-like spread by inserting into existing clusters of the older, more abundant 1.688 satellite, in events likely facilitated by microhomology-mediated repair pathways. We show that Rsp-like is abundant on extrachromosomal circular DNA in D. simulans, which may have contributed to its dynamic evolution. Intralocus satDNA expansions via unequal exchange and the movement of higher order repeats also contribute to the fluidity of the repeat landscape. We find evidence that euchromatic satDNA repeats experience cycles of proliferation and diversification somewhat analogous to bursts of transposable element proliferation. Our study lays a foundation for mechanistic studies of satDNA proliferation and the functional and evolutionary consequences of satDNA movement.
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Affiliation(s)
- John S Sproul
- Department of Biology, University of Rochester, Rochester, NY
| | | | | | - Sherif Negm
- Department of Biology, University of Rochester, Rochester, NY
| | - Xiaolu Wei
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY
| | - Isaac Wong
- Department of Biology, University of Rochester, Rochester, NY
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14
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Burgess JT, Rose M, Boucher D, Plowman J, Molloy C, Fisher M, O'Leary C, Richard DJ, O'Byrne KJ, Bolderson E. The Therapeutic Potential of DNA Damage Repair Pathways and Genomic Stability in Lung Cancer. Front Oncol 2020; 10:1256. [PMID: 32850380 PMCID: PMC7399071 DOI: 10.3389/fonc.2020.01256] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/17/2020] [Indexed: 12/16/2022] Open
Abstract
Despite advances in our understanding of the molecular biology of the disease and improved therapeutics, lung cancer remains the most common cause of cancer-related deaths worldwide. Therefore, an unmet need remains for improved treatments, especially in advanced stage disease. Genomic instability is a universal hallmark of all cancers. Many of the most commonly prescribed chemotherapeutics, including platinum-based compounds such as cisplatin, target the characteristic genomic instability of tumors by directly damaging the DNA. Chemotherapies are designed to selectively target rapidly dividing cells, where they cause critical DNA damage and subsequent cell death (1, 2). Despite the initial efficacy of these drugs, the development of chemotherapy resistant tumors remains the primary concern for treatment of all lung cancer patients. The correct functioning of the DNA damage repair machinery is essential to ensure the maintenance of normal cycling cells. Dysregulation of these pathways promotes the accumulation of mutations which increase the potential of malignancy. Following the development of the initial malignancy, the continued disruption of the DNA repair machinery may result in the further progression of metastatic disease. Lung cancer is recognized as one of the most genomically unstable cancers (3). In this review, we present an overview of the DNA damage repair pathways and their contributions to lung cancer disease occurrence and progression. We conclude with an overview of current targeted lung cancer treatments and their evolution toward combination therapies, including chemotherapy with immunotherapies and antibody-drug conjugates and the mechanisms by which they target DNA damage repair pathways.
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Affiliation(s)
- Joshua T Burgess
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Maddison Rose
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Didier Boucher
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Jennifer Plowman
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Christopher Molloy
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Mark Fisher
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Connor O'Leary
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Derek J Richard
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Kenneth J O'Byrne
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Emma Bolderson
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
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15
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Genome instability in multiple myeloma. Leukemia 2020; 34:2887-2897. [PMID: 32651540 DOI: 10.1038/s41375-020-0921-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022]
Abstract
Multiple myeloma (MM) is an incurable plasma cell malignancy characterized by clonal proliferation of plasma cells and a heterogenous genomic landscape. Copy number and structural changes due to chromosomal instability (CIN) are common features of MM. In this review, we describe how primary and secondary genetic events caused by CIN can contribute to increased instability across the genome of malignant plasma cells; with a focus on specific driver genomic events, and how they interfere with cell-cycle checkpoints, to prompt accelerated proliferation. We also provide insight into other forms of CIN, such as chromothripsis and chromoplexy. We evaluate how the tumor microenvironment can contribute to a further increase in chromosomal instability in myeloma cells. Lastly, we highlight the role of certain mutational signatures in leading to high mutation rate and genome instability in certain MM patients. We suggest that assessing CIN in MM and its precursors states may help improve predicting the risk of progression to symptomatic disease and relapse and identifying future therapeutic targets.
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16
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Ray S, Breuer G, DeVeaux M, Zelterman D, Bindra R, Sweasy JB. DNA polymerase beta participates in DNA End-joining. Nucleic Acids Res 2019; 46:242-255. [PMID: 29161447 PMCID: PMC5758893 DOI: 10.1093/nar/gkx1147] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 10/31/2017] [Indexed: 12/21/2022] Open
Abstract
DNA double strand breaks (DSBs) are one of the most deleterious lesions and if left unrepaired, they lead to cell death, genomic instability and carcinogenesis. Cells combat DSBs by two pathways: homologous recombination (HR) and non-homologous end-joining (NHEJ), wherein the two DNA ends are re-joined. Recently a back-up NHEJ pathway has been reported and is referred to as alternative NHEJ (aNHEJ), which joins ends but results in deletions and insertions. NHEJ requires processing enzymes including nucleases and polymerases, although the roles of these enzymes are poorly understood. Emerging evidence indicates that X family DNA polymerases lambda (Pol λ) and mu (Pol μ) promote DNA end-joining. Here, we show that DNA polymerase beta (Pol β), another member of the X family of DNA polymerases, plays a role in aNHEJ. In the absence of DNA Pol β, fewer small deletions are observed. In addition, depletion of Pol β results in cellular sensitivity to bleomycin and DNA protein kinase catalytic subunit inhibitors due to defective repair of DSBs. In summary, our results indicate that Pol β in functions in aNHEJ and provide mechanistic insight into its role in this process.
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Affiliation(s)
- Sreerupa Ray
- Department of Therapeutic Radiology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
| | - Gregory Breuer
- Department of Therapeutic Radiology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA.,Department of Pathology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
| | - Michelle DeVeaux
- School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
| | - Daniel Zelterman
- School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
| | - Ranjit Bindra
- Department of Therapeutic Radiology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA.,Department of Pathology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
| | - Joann B Sweasy
- Department of Therapeutic Radiology, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA.,Department of Genetics, School of Public Health, Yale University School of Medicine, New Haven, CT 06520-8034, USA
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17
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Frequency of DNA end joining in trans is not determined by the predamage spatial proximity of double-strand breaks in yeast. Proc Natl Acad Sci U S A 2019; 116:9481-9490. [PMID: 31019070 DOI: 10.1073/pnas.1818595116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
DNA double-strand breaks (DSBs) are serious genomic insults that can lead to chromosomal rearrangements if repaired incorrectly. To gain insight into the nuclear mechanisms contributing to these rearrangements, we developed an assay in yeast to measure cis (same site) vs. trans (different site) repair for the majority process of precise nonhomologous end joining (NHEJ). In the assay, the HO endonuclease gene is placed between two HO cut sites such that HO expression is self-terminated upon induction. We further placed an additional cut site in various genomic loci such that NHEJ in trans led to expression of a LEU2 reporter gene. Consistent with prior reports, cis NHEJ was more efficient than trans NHEJ. However, unlike homologous recombination, where spatial distance between a single DSB and donor locus was previously shown to correlate with repair efficiency, trans NHEJ frequency remained essentially constant regardless of the position of the two DSB loci, even when they were on the same chromosome or when two trans repair events were put in competition. Repair of similar DSBs via single-strand annealing of short terminal direct repeats showed substantially higher repair efficiency and trans repair frequency, but still without a strong correlation of trans repair to genomic position. Our results support a model in which yeast cells mobilize, and perhaps compartmentalize, multiple DSBs in a manner that no longer reflects the predamage position of two broken loci.
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18
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RAGs usurp cellular factors for both breaking and repairing. Blood 2019; 133:773-774. [DOI: 10.1182/blood-2019-01-892729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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Haakenson JK, Huang R, Smider VV. Diversity in the Cow Ultralong CDR H3 Antibody Repertoire. Front Immunol 2018; 9:1262. [PMID: 29915599 PMCID: PMC5994613 DOI: 10.3389/fimmu.2018.01262] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/18/2018] [Indexed: 01/26/2023] Open
Abstract
Typical antibodies found in humans and mice usually have short CDR H3s and generally flat binding surfaces. However, cows possess a subset of antibodies with ultralong CDR H3s that can range up to 70 amino acids and form a unique “stalk and knob” structure, with the knob protruding far out of the antibody surface, where it has the potential to bind antigens with concave epitopes. Activation-induced cytidine deaminase (AID) has a proven role in diversifying antibody repertoires in humoral immunity, and it has been found to induce somatic hypermutation in bovine immunoglobulin genes both before and after contact with antigen. Due to limited use of variable and diversity genes in the V(D)J recombination events that produce ultralong CDR H3 antibodies in cows, the diversity in the bovine ultralong antibody repertoire has been proposed to rely on AID-induced mutations targeted to the IGHD8-2 gene that encodes the entire knob region. In this review, we discuss the genetics, structures, and diversity of bovine ultralong antibodies, as well as the role of AID in creating a diverse antibody repertoire.
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Affiliation(s)
- Jeremy K Haakenson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Ruiqi Huang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Vaughn V Smider
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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20
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Srivastava S, Dahal S, Naidu SJ, Anand D, Gopalakrishnan V, Kooloth Valappil R, Raghavan SC. DNA double-strand break repair in Penaeus monodon is predominantly dependent on homologous recombination. DNA Res 2017; 24:117-128. [PMID: 28431013 PMCID: PMC5397610 DOI: 10.1093/dnares/dsw059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 12/08/2016] [Indexed: 11/13/2022] Open
Abstract
DNA double-strand breaks (DSBs) are mostly repaired by nonhomologous end joining (NHEJ) and homologous recombination (HR) in higher eukaryotes. In contrast, HR-mediated DSB repair is the major double-strand break repair pathway in lower order organisms such as bacteria and yeast. Penaeus monodon, commonly known as black tiger shrimp, is one of the economically important crustaceans facing large-scale mortality due to exposure to infectious diseases. The animals can also get exposed to chemical mutagens under the culture conditions as well as in wild. Although DSB repair mechanisms have been described in mammals and some invertebrates, its mechanism is unknown in the shrimp species. In the present study, we show that HR-mediated DSB repair is the predominant mode of repair in P. monodon. Robust repair was observed at a temperature of 30 °C, when 2 µg of cell-free extract derived from hepatopancreas was used for the study. Although HR occurred through both reciprocal recombination and gene conversion, the latter was predominant when the bacterial colonies containing recombinants were evaluated. Unlike mammals, NHEJ-mediated DSB repair was undetectable in P. monodon. However, we could detect evidence for an alternative mode of NHEJ that uses microhomology, termed as microhomology-mediated end joining (MMEJ). Interestingly, unlike HR, MMEJ was predominant at lower temperatures. Therefore, the results suggest that, while HR is major DSB repair pathway in shrimp, MMEJ also plays a role in ensuring the continuity and stability of the genome.
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Affiliation(s)
- Shikha Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sharanya J Naidu
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Deepika Anand
- ICAR-Central Institute of Fisheries Education, Mumbai 400 061, India
| | - Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | | | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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21
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Evaluation of Structural Factors Potentially Implicated in Acute Lymphoblastic Leukemia: A report of the MIGICCL. Arch Med Res 2017; 47:515-520. [PMID: 28262192 DOI: 10.1016/j.arcmed.2016.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/23/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND AIMS Acute lymphoblastic leukemia (ALL) is the most common cancer in the pediatric population; ∼80% of the cases show some translocation. Translocations that result in ALL are due to chromosome breaks. However, the exact mechanisms that cause these breaks have not been well studied. A detailed search of the breakpoints associated with ALL reported in the NCBI database shows that some are concentrated in limited regions of the chromosome, whereas others are scattered throughout. Therefore, the objective of this study was to identify the structural factors involved in chromosomal breaks in ALL. METHODS We performed several bioinformatic studies on the sequences where chromosomal breakpoints have been reported in search of rearrangements: areas of high similarity, thermodynamic stability, composition and conformation of the DNA. RESULTS Certain factors may influence chromosome breaks and are capable of predicting the propensity towards these types of events. CONCLUSIONS These findings may be useful in the design of molecular techniques able to detect these changes in ALL.
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22
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Le MX, Haddad D, Ling AK, Li C, So CC, Chopra A, Hu R, Angulo JF, Moffat J, Martin A. Kin17 facilitates multiple double-strand break repair pathways that govern B cell class switching. Sci Rep 2016; 6:37215. [PMID: 27853268 PMCID: PMC5112545 DOI: 10.1038/srep37215] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/13/2016] [Indexed: 11/09/2022] Open
Abstract
Class switch recombination (CSR) in B cells requires the timely repair of DNA double-stranded breaks (DSBs) that result from lesions produced by activation-induced cytidine deaminase (AID). Through a genome-wide RNAi screen, we identified Kin17 as a gene potentially involved in the maintenance of CSR in murine B cells. In this study, we confirm a critical role for Kin17 in CSR independent of AID activity. Furthermore, we make evident that DSBs generated by AID or ionizing radiation require Kin17 for efficient repair and resolution. Our report shows that reduced Kin17 results in an elevated deletion frequency following AID mutational activity in the switch region. In addition, deficiency in Kin17 affects the functionality of multiple DSB repair pathways, namely homologous recombination, non-homologous end-joining, and alternative end-joining. This report demonstrates the importance of Kin17 as a critical factor that acts prior to the repair phase of DSB repair and is of bona fide importance for CSR.
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Affiliation(s)
- Michael X. Le
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Dania Haddad
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Alexanda K. Ling
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Conglei Li
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Clare C. So
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Amit Chopra
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Rui Hu
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
| | - Jaime F. Angulo
- Laboratoire de Radio Toxicologie, CEA, Université Paris-Saclay, Arpajon, 91297, France
| | - Jason Moffat
- Donnelly Centre and Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, M5S1A8, Canada
| | - Alberto Martin
- Department of Immunology, University of Toronto, Medical Sciences Building, Toronto, Ontario, M5S1A8, Canada
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23
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Laffleur B, Dalloul Z, Dalloul I, Le Noir S, Cogné M. [When immunoglobulin genes assemble with bricks from other chromosomes]. Med Sci (Paris) 2016; 32:677-80. [PMID: 27615167 DOI: 10.1051/medsci/20163208006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Brice Laffleur
- Department of immunology, Columbia university, New York, États-Unis
| | - Zeinab Dalloul
- Université de Limoges, CNRS UMR 7276, Contrôle de la réponse immune et lymphoprolifération, faculté de médecine, 2, rue du Docteur Marcland, 87025 Limoges, France
| | - Iman Dalloul
- Université de Limoges, CNRS UMR 7276, Contrôle de la réponse immune et lymphoprolifération, faculté de médecine, 2, rue du Docteur Marcland, 87025 Limoges, France
| | - Sandrine Le Noir
- Université de Limoges, CNRS UMR 7276, Contrôle de la réponse immune et lymphoprolifération, faculté de médecine, 2, rue du Docteur Marcland, 87025 Limoges, France
| | - Michel Cogné
- Université de Limoges, CNRS UMR 7276, Contrôle de la réponse immune et lymphoprolifération, faculté de médecine, 2, rue du Docteur Marcland, 87025 Limoges, France - Institut universitaire de France, Paris, France
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24
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Meek K, Xu Y, Bailie C, Yu K, Neal JA. The ATM Kinase Restrains Joining of Both VDJ Signal and Coding Ends. THE JOURNAL OF IMMUNOLOGY 2016; 197:3165-3174. [PMID: 27574300 DOI: 10.4049/jimmunol.1600597] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 08/06/2016] [Indexed: 11/19/2022]
Abstract
The evidence that ATM affects resolution of RAG-induced DNA double-strand breaks is profuse and unequivocal; moreover, it is clear that the RAG complex itself cooperates (in an undetermined way) with ATM to facilitate repair of these double-strand breaks by the classical nonhomologous end-joining pathway. The mechanistic basis for the cooperation between ATM and the RAG complex has not been defined, although proposed models invoke ATM and RAG2's C terminus in maintaining the RAG postcleavage complex. In this study, we show that ATM reduces the rate of both coding and signal joining in a robust episomal assay; we suggest that this is the result of increased stability of the postcleavage complex. ATM's ability to inhibit VDJ joining requires its enzymatic activity. The noncore C termini of both RAG1 and RAG2 are also required for ATM's capacity to limit signal (but not coding) joining. Moreover, potential phosphorylation targets within the C terminus of RAG2 are also required for ATM's capacity to limit signal joining. These data suggest a model whereby the RAG signal end complex is stabilized by phosphorylation of RAG2 by ATM.
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Affiliation(s)
- Katheryn Meek
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; .,Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; and
| | - Yao Xu
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.,Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; and
| | - Caleb Bailie
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.,Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; and
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, College of Human Medicine, Michigan State University, East Lansing, MI 48824
| | - Jessica A Neal
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.,Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; and
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25
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Neal JA, Xu Y, Abe M, Hendrickson E, Meek K. Restoration of ATM Expression in DNA-PKcs-Deficient Cells Inhibits Signal End Joining. THE JOURNAL OF IMMUNOLOGY 2016; 196:3032-42. [PMID: 26921311 DOI: 10.4049/jimmunol.1501654] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 01/26/2016] [Indexed: 11/19/2022]
Abstract
Unlike most DNA-dependent protein kinase, catalytic subunit (DNA-PKcs)-deficient mouse cell strains, we show in the present study that targeted deletion of DNA-PKcs in two different human cell lines abrogates VDJ signal end joining in episomal assays. Although the mechanism is not well defined, DNA-PKcs deficiency results in spontaneous reduction of ATM expression in many cultured cell lines (including those examined in this study) and in DNA-PKcs-deficient mice. We considered that varying loss of ATM expression might explain differences in signal end joining in different cell strains and animal models, and we investigated the impact of ATM and/or DNA-PKcs loss on VDJ recombination in cultured human and rodent cell strains. To our surprise, in DNA-PKcs-deficient mouse cell strains that are proficient in signal end joining, restoration of ATM expression markedly inhibits signal end joining. In contrast, in DNA-PKcs-deficient cells that are deficient in signal end joining, complete loss of ATM enhances signal (but not coding) joint formation. We propose that ATM facilitates restriction of signal ends to the classical nonhomologous end-joining pathway.
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Affiliation(s)
- Jessica A Neal
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824
| | - Yao Xu
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824
| | - Masumi Abe
- National Institute of Radiological Sciences, Chiba 263-8555, Japan; and
| | - Eric Hendrickson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Katheryn Meek
- Department of Microbiology and Molecular Genetics, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824;
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26
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Nagy Z, Kalousi A, Furst A, Koch M, Fischer B, Soutoglou E. Tankyrases Promote Homologous Recombination and Check Point Activation in Response to DSBs. PLoS Genet 2016; 12:e1005791. [PMID: 26845027 PMCID: PMC4741384 DOI: 10.1371/journal.pgen.1005791] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/16/2015] [Indexed: 11/18/2022] Open
Abstract
DNA lesions are sensed by a network of proteins that trigger the DNA damage response (DDR), a signaling cascade that acts to delay cell cycle progression and initiate DNA repair. The Mediator of DNA damage Checkpoint protein 1 (MDC1) is essential for spreading of the DDR signaling on chromatin surrounding Double Strand Breaks (DSBs) by acting as a scaffold for PI3K kinases and for ubiquitin ligases. MDC1 also plays a role both in Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR) repair pathways. Here we identify two novel binding partners of MDC1, the poly (ADP-ribose) Polymerases (PARPs) TNKS1 and 2. We find that TNKSs are recruited to DNA lesions by MDC1 and regulate DNA end resection and BRCA1A complex stabilization at lesions leading to efficient DSB repair by HR and proper checkpoint activation. MDC1 recruit Tankyrases to DNA lesions to regulate homologous recombination and to control check-point activation.
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Affiliation(s)
- Zita Nagy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Alkmini Kalousi
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Audrey Furst
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Marc Koch
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Benoit Fischer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Evi Soutoglou
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U964, Illkirch, France
- Centre National de Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
- * E-mail:
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27
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Redundant function of DNA ligase 1 and 3 in alternative end-joining during immunoglobulin class switch recombination. Proc Natl Acad Sci U S A 2016; 113:1261-6. [PMID: 26787901 DOI: 10.1073/pnas.1521630113] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
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.
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28
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Sinha S, Villarreal D, Shim EY, Lee SE. Risky business: Microhomology-mediated end joining. Mutat Res 2016; 788:17-24. [PMID: 26790771 DOI: 10.1016/j.mrfmmm.2015.12.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/03/2015] [Accepted: 12/22/2015] [Indexed: 11/16/2022]
Abstract
Prevalence of microhomology (MH) at the breakpoint junctions in somatic and germ-line chromosomal rearrangements and in the programmed immune receptor rearrangements from cells deficient in classical end joining reveals an enigmatic process called MH-mediated end joining (MMEJ). MMEJ repairs DNA double strand breaks (DSBs) by annealing flanking MH and deleting genetic information at the repair junctions from yeast to humans. Being genetically distinct from canonical DNA DSB pathways, MMEJ is involved with the fusions of eroded/uncapped telomeres as well as with the assembly of chromosome fragments in chromothripsis. In this review article, we will discuss an up-to-date model representing the MMEJ process and the mechanism by which cells regulate MMEJ to limit repair-associated mutagenesis. We will also describe the possible therapeutic gains resulting from the inhibition of MMEJ in recombination deficient cancers. Lastly, we will embark on two contentious issues associated with MMEJ such as the significance of MH at the repair junction to be the hallmark of MMEJ and the relationship of MMEJ to other mechanistically related DSB repair pathways.
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Affiliation(s)
- Supriya Sinha
- Department of Molecular Medicine, Institute of Biotechnology, United States
| | - Diana Villarreal
- Children's Hospital of San Antonio, Baylor College of Medicine, San Antonio, TX 78207, United States
| | - Eun Yong Shim
- Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, TX 78229, United States
| | - Sang Eun Lee
- Department of Molecular Medicine, Institute of Biotechnology, United States; Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, TX 78229, United States.
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29
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Identification and Characterization of the V(D)J Recombination Activating Gene 1 in Long-Term Memory of Context Fear Conditioning. Neural Plast 2015; 2016:1752176. [PMID: 26843989 PMCID: PMC4710954 DOI: 10.1155/2016/1752176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/12/2015] [Indexed: 12/17/2022] Open
Abstract
An increasing body of evidence suggests that mechanisms related to the introduction and repair of DNA double strand breaks (DSBs) may be associated with long-term memory (LTM) processes. Previous studies from our group suggested that factors known to function in DNA recombination/repair machineries, such as DNA ligases, polymerases, and DNA endonucleases, play a role in LTM. Here we report data using C57BL/6 mice showing that the V(D)J recombination-activating gene 1 (RAG1), which encodes a factor that introduces DSBs in immunoglobulin and T-cell receptor genes, is induced in the amygdala, but not in the hippocampus, after context fear conditioning. Amygdalar induction of RAG1 mRNA, measured by real-time PCR, was not observed in context-only or shock-only controls, suggesting that the context fear conditioning response is related to associative learning processes. Furthermore, double immunofluorescence studies demonstrated the neuronal localization of RAG1 protein in amygdalar sections prepared after perfusion and fixation. In functional studies, intra-amygdalar injections of RAG1 gapmer antisense oligonucleotides, given 1 h prior to conditioning, resulted in amygdalar knockdown of RAG1 mRNA and a significant impairment in LTM, tested 24 h after training. Overall, these findings suggest that the V(D)J recombination-activating gene 1, RAG1, may play a role in LTM consolidation.
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30
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Tadi SK, Sebastian R, Dahal S, Babu RK, Choudhary B, Raghavan SC. Microhomology-mediated end joining is the principal mediator of double-strand break repair during mitochondrial DNA lesions. Mol Biol Cell 2015; 27:223-35. [PMID: 26609070 PMCID: PMC4713127 DOI: 10.1091/mbc.e15-05-0260] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 11/18/2015] [Indexed: 12/13/2022] Open
Abstract
Repair of double-strand breaks in mammalian mitochondria depends on microhomology-mediated end joining (MMEJ). Classical NHEJ is not detectable in mitochondria. DNA ligase III, but not ligase IV or ligase I, is involved in mitochondrial MMEJ. The protein machinery involved in miitochondrial MMEJ includes CtIP, FEN1, ligase III, MRE11, and PARP1. Mitochondrial DNA (mtDNA) deletions are associated with various mitochondrial disorders. The deletions identified in humans are flanked by short, directly repeated mitochondrial DNA sequences; however, the mechanism of such DNA rearrangements has yet to be elucidated. In contrast to nuclear DNA (nDNA), mtDNA is more exposed to oxidative damage, which may result in double-strand breaks (DSBs). Although DSB repair in nDNA is well studied, repair mechanisms in mitochondria are not characterized. In the present study, we investigate the mechanisms of DSB repair in mitochondria using in vitro and ex vivo assays. Whereas classical NHEJ (C-NHEJ) is undetectable, microhomology-mediated alternative NHEJ efficiently repairs DSBs in mitochondria. Of interest, robust microhomology-mediated end joining (MMEJ) was observed with DNA substrates bearing 5-, 8-, 10-, 13-, 16-, 19-, and 22-nt microhomology. Furthermore, MMEJ efficiency was enhanced with an increase in the length of homology. Western blotting, immunoprecipitation, and protein inhibition assays suggest the involvement of CtIP, FEN1, MRE11, and PARP1 in mitochondrial MMEJ. Knockdown studies, in conjunction with other experiments, demonstrated that DNA ligase III, but not ligase IV or ligase I, is primarily responsible for the final sealing of DSBs during mitochondrial MMEJ. These observations highlight the central role of MMEJ in maintenance of mammalian mitochondrial genome integrity and is likely relevant for deletions observed in many human mitochondrial disorders.
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Affiliation(s)
- Satish Kumar Tadi
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Robin Sebastian
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Ravi K Babu
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560 100, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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31
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Recruitment of RAG1 and RAG2 to Chromatinized DNA during V(D)J Recombination. Mol Cell Biol 2015; 35:3701-13. [PMID: 26303526 DOI: 10.1128/mcb.00219-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/09/2015] [Indexed: 11/20/2022] Open
Abstract
V(D)J recombination is initiated by the binding of the RAG1 and RAG2 proteins to recombination signal sequences (RSSs) that consist of conserved heptamer and nonamer sequences separated by a spacer of either 12 or 23 bp. Here, we used RAG-inducible pro-B v-Abl cell lines in conjunction with chromatin immunoprecipitation to better understand the protein and RSS requirements for RAG recruitment to chromatin. Using a catalytic mutant form of RAG1 to prevent recombination, we did not observe cooperation between RAG1 and RAG2 in their recruitment to endogenous Jκ gene segments over a 48-h time course. Using retroviral recombination substrates, we found that RAG1 was recruited inefficiently to substrates lacking an RSS or containing a single RSS, better to substrates with two 12-bp RSSs (12RSSs) or two 23-bp RSSs (23RSSs), and more efficiently to a substrate with a 12/23RSS pair. RSS mutagenesis demonstrated a major role for the nonamer element in RAG1 binding, and correspondingly, a cryptic RSS consisting of a repeat of CA dinucleotides, which poorly re-creates the nonamer, was ineffective in recruiting RAG1. Our findings suggest that 12RSS-23RSS cooperation (the "12/23 rule") is important not only for regulating RAG-mediated DNA cleavage but also for the efficiency of RAG recruitment to chromatin.
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32
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Lin W, Yuan N, Wang Z, Cao Y, Fang Y, Li X, Xu F, Song L, Wang J, Zhang H, Yan L, Xu L, Zhang X, Zhang S, Wang J. Autophagy confers DNA damage repair pathways to protect the hematopoietic system from nuclear radiation injury. Sci Rep 2015; 5:12362. [PMID: 26197097 PMCID: PMC4508834 DOI: 10.1038/srep12362] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/26/2015] [Indexed: 12/23/2022] Open
Abstract
Autophagy is essentially a metabolic process, but its in vivo role in nuclear radioprotection remains unexplored. We observed that ex vivo autophagy activation reversed the proliferation inhibition, apoptosis, and DNA damage in irradiated hematopoietic cells. In vivo autophagy activation improved bone marrow cellularity following nuclear radiation exposure. In contrast, defective autophagy in the hematopoietic conditional mouse model worsened the hematopoietic injury, reactive oxygen species (ROS) accumulation and DNA damage caused by nuclear radiation exposure. Strikingly, in vivo defective autophagy caused an absence or reduction in regulatory proteins critical to both homologous recombination (HR) and non-homologous end joining (NHEJ) DNA damage repair pathways, as well as a failure to induce these proteins in response to nuclear radiation. In contrast, in vivo autophagy activation increased most of these proteins in hematopoietic cells. DNA damage assays confirmed the role of in vivo autophagy in the resolution of double-stranded DNA breaks in total bone marrow cells as well as bone marrow stem and progenitor cells upon whole body irradiation. Hence, autophagy protects the hematopoietic system against nuclear radiation injury by conferring and intensifying the HR and NHEJ DNA damage repair pathways and by removing ROS and inhibiting apoptosis.
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Affiliation(s)
- Weiwei Lin
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Na Yuan
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Zhen Wang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Yan Cao
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Yixuan Fang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Xin Li
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Fei Xu
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Lin Song
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Jian Wang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Han Zhang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Lili Yan
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Li Xu
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Xiaoying Zhang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Suping Zhang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
| | - Jianrong Wang
- Hematology Center of Cyrus Tang Medical Institute, Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Jiangsu Key Laboratory for Stem Cell Research, Soochow University School of Medicine, Suzhou 215123, China
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Karo JM, Sun JC. Novel molecular mechanism for generating NK-cell fitness and memory. Eur J Immunol 2015; 45:1906-15. [PMID: 26018782 DOI: 10.1002/eji.201445339] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/21/2015] [Accepted: 05/27/2015] [Indexed: 12/28/2022]
Abstract
The mammalian immune system has been traditionally subdivided into two compartments known as the innate and the adaptive. T cells and B cells, which rearrange their antigen-receptor genes using the RAG recombinase, comprise the adaptive arm of immunity. Meanwhile, every other white blood cell has been grouped together under the broad umbrella of innate immunity, including NK cells. NK cells are considered innate lymphocytes because of their rapid responses to stressed cells and their ability to develop without receptor gene rearrangement (i.e. in RAG-deficient mice). However, new findings implicate a critical function for RAG proteins during NK-cell ontogeny, and suggest a novel mechanism by which controlled DNA breaks during NK-cell development dictate the fitness, function, and longevity of these cells. This review highlights recent work describing how DNA break events can impact cellular differentiation and fitness in a variety of cell types and settings.
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Affiliation(s)
- Jenny M Karo
- Immunology Program and Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Joseph C Sun
- Immunology Program and Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Karo JM, Schatz DG, Sun JC. The RAG recombinase dictates functional heterogeneity and cellular fitness in natural killer cells. Cell 2015; 159:94-107. [PMID: 25259923 DOI: 10.1016/j.cell.2014.08.026] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/22/2014] [Accepted: 08/05/2014] [Indexed: 01/30/2023]
Abstract
The emergence of recombination-activating genes (RAGs) in jawed vertebrates endowed adaptive immune cells with the ability to assemble a diverse set of antigen receptor genes. In contrast, innate lymphocytes, such as natural killer (NK) cells, are not believed to require RAGs. Here, we report that NK cells unable to express RAGs or RAG endonuclease activity during ontogeny exhibit a cell-intrinsic hyperresponsiveness but a diminished capacity to survive following virus-driven proliferation, a reduced expression of DNA damage response mediators, and defects in the repair of DNA breaks. Evidence for this novel function of RAG has also been observed in T cells and innate lymphoid cells (ILCs), revealing an unexpected role for RAG proteins beyond V(D)J recombination. We propose that DNA cleavage events mediated by RAG endow developing adaptive and innate lymphocytes with a cellular "fitness" that safeguards their persistence later in life during episodes of rapid proliferation or cellular stress.
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Affiliation(s)
- Jenny M Karo
- Immunology Program and Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - David G Schatz
- Department of Immunobiology and the Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joseph C Sun
- Immunology Program and Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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John F, George J, Srivastava M, Hassan PA, Aswal VK, Karki SS, Raghavan SC. Pluronic copolymer encapsulated SCR7 as a potential anticancer agent. Faraday Discuss 2015; 177:155-61. [DOI: 10.1039/c4fd00176a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nonhomologous end joining (NHEJ) of DNA double strand breaks (DSBs) inside cells can be selectively inhibited by 5,6-bis-(benzylideneamino)-2-mercaptopyrimidin-4-ol (SCR7) which possesses anticancer properties. The hydrophobicity of SCR7 decreases its bioavailability which is a major setback in the utilization of this compound as a therapeutic agent. In order to circumvent the drawback of SCR7, we prepared a polymer encapsulated form of SCR7. The physical interaction of SCR7 and Pluronic® copolymer is evident from different analytical techniques. The in vitro cytotoxicity of the drug formulations is established using the MTT assay.
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Affiliation(s)
- Franklin John
- Biotechnology Laboratory
- PG and Research Department of Chemistry
- Sacred Heart College
- Kochi 682 013
- India
| | - Jinu George
- Biotechnology Laboratory
- PG and Research Department of Chemistry
- Sacred Heart College
- Kochi 682 013
- India
| | - Mrinal Srivastava
- Department of Biochemistry
- Indian Institute of Science
- Bangalore 560 012
- India
| | - P. A. Hassan
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai 400 085
- India
| | - V. K. Aswal
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai 400 085
- India
| | - Subhas. S. Karki
- Department of Pharmaceutical Chemistry
- KLE University
- Bangalore 560 010
- India
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Anand RP, Tsaponina O, Greenwell PW, Lee CS, Du W, Petes TD, Haber JE. Chromosome rearrangements via template switching between diverged repeated sequences. Genes Dev 2014; 28:2394-406. [PMID: 25367035 PMCID: PMC4215184 DOI: 10.1101/gad.250258.114] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Anand et al. examined break-induced replication (BIR) and template switching between highly diverged sequences in S. cerevisiae, induced during repair of a site-specific double-strand break (DSB). Template switches between highly divergent sequences appear to be mechanistically distinct from the initial strand invasions that establish BIR. BIR traversing repeated DNA sequences frequently results in complex translocations analogous to those seen in mammalian cells. These results suggest that template switching among repeated genes is a potent driver of genome instability and evolution. Recent high-resolution genome analyses of cancer and other diseases have revealed the occurrence of microhomology-mediated chromosome rearrangements and copy number changes. Although some of these rearrangements appear to involve nonhomologous end-joining, many must have involved mechanisms requiring new DNA synthesis. Models such as microhomology-mediated break-induced replication (MM-BIR) have been invoked to explain these rearrangements. We examined BIR and template switching between highly diverged sequences in Saccharomyces cerevisiae, induced during repair of a site-specific double-strand break (DSB). Our data show that such template switches are robust mechanisms that give rise to complex rearrangements. Template switches between highly divergent sequences appear to be mechanistically distinct from the initial strand invasions that establish BIR. In particular, such jumps are less constrained by sequence divergence and exhibit a different pattern of microhomology junctions. BIR traversing repeated DNA sequences frequently results in complex translocations analogous to those seen in mammalian cells. These results suggest that template switching among repeated genes is a potent driver of genome instability and evolution.
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Affiliation(s)
- Ranjith P Anand
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA
| | - Olga Tsaponina
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA
| | - Patricia W Greenwell
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Cheng-Sheng Lee
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA
| | - Wei Du
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA
| | - Thomas D Petes
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - James E Haber
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, Massachusetts 02254, USA;
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Souliotis VL, Sfikakis PP. Increased DNA double-strand breaks and enhanced apoptosis in patients with lupus nephritis. Lupus 2014; 24:804-15. [PMID: 25542905 DOI: 10.1177/0961203314565413] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 11/25/2014] [Indexed: 11/16/2022]
Abstract
OBJECTIVE DNA double-strand breaks (DSBs) lead to mutations, genomic instability and apoptotic death, whereas accumulation of apoptotic cells results in excessive autoantigen presentation and autoantibody formation. We aimed to measure DSB levels in lupus nephritis, a severe complication of the prototypic systemic autoimmune disease. METHODS The intrinsic DNA damage and the apoptosis induction/DSB levels were evaluated in peripheral blood mononuclear cells of six patients and 10 healthy controls following exposure to genotoxic agents (melphalan, cisplatin) ex vivo. DSBs were assessed using immunofluorescence quantification of γH2AX foci and comet assay. RESULTS Intrinsic DNA damage was increased in lupus versus control cells in both assays (Olive Tail Moment units of 15.8 ± 2.3 versus 3.0 ± 1.4 in comet, p < 0.01; % γH2AX-positive cells: 13.6 ± 1.8 versus 4.6 ± 0.9, p < 0.01, respectively). Melphalan or cisplatin doses as low as 9.9 ± 4.8 or 29.8 ± 8.3 µg/ml, respectively, were sufficient to induce apoptosis in lupus cells; control cells required doses of 32.3 ± 7.7 and 67.7 ± 5.5 µg/ml, respectively. Drug-induced DSB levels were increased in lupus versus control cells, with the area under the curve (AUC) for melphalan-induced DSBs being 3050 ± 610 (% γH2AX-positive staining cells) × (drug dose) in patients and 1580 ± 350 in controls (p < 0.05); the corresponding values for cisplatin-induced AUC were 13900 ± 1800 for lupus and 4500 ± 750 for controls (p < 0.01). Interestingly, within either lupus patients or controls examined, the accumulation of DSBs correlated with apoptosis degrees (all p < 0.01). Results in lupus cells were not associated with individual disease activity level or treatment modalities at the time of the study. CONCLUSION These findings suggest a novel mechanism by which increased accumulation of DSBs may render cells more sensitive to apoptosis, thus contributing to the induction of systemic autoimmunity.
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Affiliation(s)
- V L Souliotis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, Athens, Greece
| | - P P Sfikakis
- Rheumatology Unit, First Department of Propedeutic Internal Medicine, Athens University Medical School, Athens, Greece
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John F, George J, Vartak SV, Srivastava M, Hassan PA, Aswal VK, Karki SS, Raghavan SC. Enhanced efficacy of pluronic copolymer micelle encapsulated SCR7 against cancer cell proliferation. Macromol Biosci 2014; 15:521-34. [PMID: 25515310 DOI: 10.1002/mabi.201400480] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 11/14/2014] [Indexed: 12/22/2022]
Abstract
5,6-Bis(benzylideneamino)-2-mercaptopyrimidin-4-ol (SCR7) is a new anti cancer molecule having capability to selectively inhibit non-homologous end joining (NHEJ), one of the DNA double strand break (DSB) repair pathways inside the cells. In spite of the promising potential as an anticancer agent, hydrophobicity of SCR7 decreases its bioavailability. Herein the entrapment of SCR7 in Pluronic copolymer is reported. The size of the aggregates was determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) which yields an average diameter of 23 nm. SCR7 encapsulated micelles (ES) were also characterized by small-angle neutron scattering (SANS). Evaluation of its biological properties by using a variety of techniques, including Trypan blue, MTT and Live-dead cell assays, reveal that encapsulated SCR7 can induce cytotoxicity in cancer cell lines, being more effective in breast cancer cell line. Encapsulated SCR7 treatment resulted in accumulation of DNA breaks within the cells, resulting in cell cycle arrest at G1 phase and activation of apoptosis. More importantly, we found ≈ 5 fold increase in cell death, when encapsulated SCR7 was used in comparison with SCR7 alone.
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Affiliation(s)
- Franklin John
- Biotechnology Laboratory, Department of Chemistry, Sacred Heart College, Kochi, 682 013, India
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Abstract
Since DNA double-strand breaks (DSBs) contribute to the genomic instability that drives cancer development, DSB repair pathways serve as important mechanisms for tumor suppression. Thus, genetic lesions, such as BRCA1 and BRCA2 mutations, that disrupt DSB repair are often associated with cancer susceptibility. In addition, recent evidence suggests that DSB "mis-repair", in which DSBs are resolved by an inappropriate repair pathway, can also promote genomic instability and presumably tumorigenesis. This notion has gained currency from recent cancer genome sequencing studies which have uncovered numerous chromosomal rearrangements harboring pathological DNA repair signatures. In this perspective, we discuss the factors that regulate DSB repair pathway choice and their consequences for genome stability and cancer.
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Affiliation(s)
- Tomas Aparicio
- Institute for Cancer Genetics & Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA
| | - Richard Baer
- Institute for Cancer Genetics & Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Jean Gautier
- Institute for Cancer Genetics & Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA.
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Burgess JT, Croft LV, Wallace NC, Stephenson SA, Adams MN, Ashton NW, Solomon B, O’Byrne K, Richard DJ. DNA repair pathways and their therapeutic potential in lung cancer. Lung Cancer Manag 2014. [DOI: 10.2217/lmt.14.12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
SUMMARY: Lung cancer is the leading cause of cancer-related mortality. According to WHO, 1.37 million deaths occur globally each year as a result of this disease. More than 70% of these cases are associated with prior tobacco consumption and/or cigarette smoking, suggesting a direct causal relationship. The development and progression of lung cancer and other malignancies involves the loss of genetic stability, resulting in acquisition of cumulative genetic changes; this affords the cell increased malignant potential. As such, an understanding of the mechanisms through which these events may occur will potentially allow for development of new anticancer therapies. This review will address the association between lung cancer and genetic instability, with a central focus on genetic mutations in the DNA damage repair pathways. In addition, we will discuss the potential clinical exploitation of these pathways, both in terms of biomarker staging, as well as through direct therapeutic targeting.
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Affiliation(s)
- Joshua T Burgess
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Laura V Croft
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Nathan C Wallace
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Sally-Anne Stephenson
- Eph Receptor Biology Group, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Mark N Adams
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Nicholas W Ashton
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Benjamin Solomon
- Department of Medical Oncology, Peter MacCallum Cancer Centre, East Melbourne 3002, Australia
| | - Ken O’Byrne
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
| | - Derek J Richard
- Genome Stability Laboratory, Cancer & Ageing Research Program, Institute of Health & Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Woolloongabba, Queensland 4102, Australia
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Glassy MC, Gupta R. Technical and ethical limitations in making human monoclonal antibodies (an overview). Methods Mol Biol 2014; 1060:9-36. [PMID: 24037834 DOI: 10.1007/978-1-62703-586-6_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In the broadest sense there are no longer any technical limitations to making human mAbs. Biological issues involving the type and nature of either a synthetic or a natural antibody, advantages of various B cell immunological compartments, and various assays needed to qualitate and quantitate mAbs have essentially been solved. If the target antigen is known then procedures to optimize antibody development can be readily planned out and implemented. When the antigen or target is unknown and specificity is the driving force in generating a human mAb then considerations about the nature and location of the B cell making the sought after antibody become important. And, therefore, the person the B cell is obtained from can be an ethical challenge and a limitation. For the sources of B cells special considerations must be taken to insure the anonymity and privacy of the patient. In many cases informed consent is adequate for antibody development as well as using discarded tissues. After the antibody has been generated then manufacturing technical issues become important that greatly depend upon the amounts of mAb required. For kilogram quantities then special considerations for manufacturing that include FDA guidelines will be necessary.
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Affiliation(s)
- Mark C Glassy
- Integrated Medical Sciences Association Foundation, San Diego, CA, USA
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42
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White RR, Sung P, Vestal CG, Benedetto G, Cornelio N, Richardson C. Double-strand break repair by interchromosomal recombination: an in vivo repair mechanism utilized by multiple somatic tissues in mammals. PLoS One 2013; 8:e84379. [PMID: 24349572 PMCID: PMC3862804 DOI: 10.1371/journal.pone.0084379] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 11/22/2013] [Indexed: 01/22/2023] Open
Abstract
Homologous recombination (HR) is essential for accurate genome duplication and maintenance of genome stability. In eukaryotes, chromosomal double strand breaks (DSBs) are central to HR during specialized developmental programs of meiosis and antigen receptor gene rearrangements, and form at unusual DNA structures and stalled replication forks. DSBs also result from exposure to ionizing radiation, reactive oxygen species, some anti-cancer agents, or inhibitors of topoisomerase II. Literature predicts that repair of such breaks normally will occur by non-homologous end-joining (in G1), intrachromosomal HR (all phases), or sister chromatid HR (in S/G2). However, no in vivo model is in place to directly determine the potential for DSB repair in somatic cells of mammals to occur by HR between repeated sequences on heterologs (i.e., interchromosomal HR). To test this, we developed a mouse model with three transgenes—two nonfunctional green fluorescent protein (GFP) transgenes each containing a recognition site for the I-SceI endonuclease, and a tetracycline-inducible I-SceI endonuclease transgene. If interchromosomal HR can be utilized for DSB repair in somatic cells, then I-SceI expression and induction of DSBs within the GFP reporters may result in a functional GFP+ gene. Strikingly, GFP+ recombinant cells were observed in multiple organs with highest numbers in thymus, kidney, and lung. Additionally, bone marrow cultures demonstrated interchromosomal HR within multiple hematopoietic subpopulations including multi-lineage colony forming unit–granulocyte-erythrocyte-monocyte-megakaryocte (CFU-GEMM) colonies. This is a direct demonstration that somatic cells in vivo search genome-wide for homologous sequences suitable for DSB repair, and this type of repair can occur within early developmental populations capable of multi-lineage differentiation.
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Affiliation(s)
- Ryan R. White
- Department of Biology, University of North Carolina-Charlotte, Charlotte, North Carolina, United States of America
| | - Patricia Sung
- Developmental Biology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - C. Greer Vestal
- Department of Biology, University of North Carolina-Charlotte, Charlotte, North Carolina, United States of America
| | - Gregory Benedetto
- Department of Biology, University of North Carolina-Charlotte, Charlotte, North Carolina, United States of America
| | - Noelle Cornelio
- Department of Biology, University of North Carolina-Charlotte, Charlotte, North Carolina, United States of America
| | - Christine Richardson
- Department of Biology, University of North Carolina-Charlotte, Charlotte, North Carolina, United States of America
- * E-mail:
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Mansour WY, Borgmann K, Petersen C, Dikomey E, Dahm-Daphi J. The absence of Ku but not defects in classical non-homologous end-joining is required to trigger PARP1-dependent end-joining. DNA Repair (Amst) 2013; 12:1134-42. [PMID: 24210699 DOI: 10.1016/j.dnarep.2013.10.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/30/2013] [Accepted: 10/10/2013] [Indexed: 11/27/2022]
Abstract
Classical-non-homologous end-joining (C-NHEJ) is considered the main pathway for repairing DNA double strand breaks (DSB) in mammalian cells. When C-NHEJ is defective, cells may switch DSB repair to an alternative-end-joining, which depends on PARP1 and is more erroneous. This PARP1-EJ is suggested to be active especially in tumor cells contributing to their genomic instability. Here, we define conditions under which cells would switch the repair to PARP1-EJ. Using the end jining repair substrate pEJ, we revealed that PARP1-EJ is solely used when Ku is deficient but not when either DNA-PKcs or Xrcc4 is lacking. In the latter case, DSB repair, however, could be shuttled to PARP1-EJ after additional Ku80 down-regulation, which partly rescued the DSB repair in these mutants. We demonstrate here that PARP-EJ may work on DSB ends at high fidelity manner, as evident from the unchanged efficiency upon blocking end resection by either roscovitin or mirin. Furthermore, we demonstrate for that PARP-EJ is likewise involved in the repair of multiple DSBs (I-PpoI- and IR-induced). Importantly, we identified a chromatin signature associated with the switch to PARP1-EJ which is characterized by a strong enrichment of both PARP1 and LigIII at damaged chromatin. Together, these data indicate that Ku is the main regulator for the hierarchal organization between C-NHEJ and PARP1-EJ.
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Affiliation(s)
- Wael Y Mansour
- Laboratory of Radiobiology & Experimental Radiooncology, Medical Center, Hamburg 20246, Germany; Department of Tumor Biology, National Cancer Institute, Cairo University, Cairo, Egypt.
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R/G-band boundaries: genomic instability and human disease. Clin Chim Acta 2013; 419:108-12. [PMID: 23434413 DOI: 10.1016/j.cca.2013.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/29/2013] [Accepted: 02/03/2013] [Indexed: 01/19/2023]
Abstract
The human genome is composed of large-scale compartmentalized structures resulting from variations in the amount of guanine and cytosine residues (GC%) and in the timing of DNA replication. These compartmentalized structures are related to the light- and dark-staining bands along chromosomes after the appropriate staining. Here we describe our current understanding of the biological importance of the boundaries between these light and dark bands (the so-called R/G boundaries). These R/G boundaries were identified following integration of information obtained from analyses of chromosome bands and genome sequences. This review also discusses the potential medical significance of these chromosomal regions for conditions related to genomic instability, such as cancer and neural disease. We propose that R/G-chromosomal boundaries, which correspond to regions showing a switch in replication timing from early to late S phase (early/late-switch regions) and of transition in GC%, have an extremely low number of replication origins and more non-B-form DNA structures than other genomic regions. Further, we suggest that genes located at R/G boundaries and which contain such DNA sequences have an increased risk of genetic instability and of being associated with human diseases. Finally, we propose strategies for genome and epigenome analyses based on R/G boundaries.
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Davidson D, Amrein L, Panasci L, Aloyz R. Small Molecules, Inhibitors of DNA-PK, Targeting DNA Repair, and Beyond. Front Pharmacol 2013; 4:5. [PMID: 23386830 PMCID: PMC3560216 DOI: 10.3389/fphar.2013.00005] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 01/08/2013] [Indexed: 12/13/2022] Open
Abstract
Many current chemotherapies function by damaging genomic DNA in rapidly dividing cells ultimately leading to cell death. This therapeutic approach differentially targets cancer cells that generally display rapid cell division compared to normal tissue cells. However, although these treatments are initially effective in arresting tumor growth and reducing tumor burden, resistance and disease progression eventually occur. A major mechanism underlying this resistance is increased levels of cellular DNA repair. Most cells have complex mechanisms in place to repair DNA damage that occurs due to environmental exposures or normal metabolic processes. These systems, initially overwhelmed when faced with chemotherapy induced DNA damage, become more efficient under constant selective pressure and as a result chemotherapies become less effective. Thus, inhibiting DNA repair pathways using target specific small molecule inhibitors may overcome cellular resistance to DNA damaging chemotherapies. Non-homologous end joining a major mechanism for the repair of double-strand breaks (DSB) in DNA is regulated in part by the serine/threonine kinase, DNA dependent protein kinase (DNA-PK). The DNA-PK holoenzyme acts as a scaffold protein tethering broken DNA ends and recruiting other repair molecules. It also has enzymatic activity that may be involved in DNA damage signaling. Because of its’ central role in repair of DSBs, DNA-PK has been the focus of a number of small molecule studies. In these studies specific DNA-PK inhibitors have shown efficacy in synergizing chemotherapies in vitro. However, compounds currently known to specifically inhibit DNA-PK are limited by poor pharmacokinetics: these compounds have poor solubility and have high metabolic lability in vivo leading to short serum half-lives. Future improvement in DNA-PK inhibition will likely be achieved by designing new molecules based on the recently reported crystallographic structure of DNA-PK. Computer based drug design will not only assist in identifying novel functional moieties to replace the metabolically labile morpholino group but will also facilitate the design of molecules to target the DNA-PKcs/Ku80 interface or one of the autophosphorylation sites.
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Affiliation(s)
- David Davidson
- Department of Oncology, Segal Cancer Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University Montreal, QC, Canada
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Oh S, Wang Y, Zimbric J, Hendrickson EA. Human LIGIV is synthetically lethal with the loss of Rad54B-dependent recombination and is required for certain chromosome fusion events induced by telomere dysfunction. Nucleic Acids Res 2012; 41:1734-49. [PMID: 23275564 PMCID: PMC3561972 DOI: 10.1093/nar/gks1326] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Classic non-homologous end joining (C-NHEJ) is the predominant DNA double-strand break repair pathway in humans. Although seven genes Ku70, Ku86, DNA-PKcs, Artemis, DNA Ligase IV (LIGIV), X-ray cross-complementing group 4 and XRCC4-like factor are required for C-NHEJ, several of them also have ancillary functions. For example, Ku70:Ku86 possesses an essential telomere maintenance activity. In contrast, LIGIV is believed to function exclusively in C-NHEJ. Moreover, a viable LIGIV-null human B-cell line and LIGIV-reduced patient cell lines have been described. Together, these observations suggest that LIGIV (and hence C-NHEJ), albeit important, is nonetheless dispensable, whereas Ku70:Ku86 and telomere maintenance are essential. To confirm this hypothesis, we inactivated LIGIV in the epithelial human cell line, HCT116. The resulting LIGIV-null cell line was viable, verifying that the gene and C-NHEJ are not essential. However, functional inactivation of RAD54B, a key homologous recombination factor, in the LIGIV-null background yielded no viable clones, suggesting that the combined absence of RAD54B/homologous recombination and C-NHEJ is synthetically lethal. Finally, we demonstrate that LIGIV is differentially required for certain chromosome fusion events induced by telomere dysfunction—used for those owing to the overexpression of a dominant negative version of telomere recognition factor 2, but not used for those owing to absence of Ku70:Ku86.
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Affiliation(s)
- Sehyun Oh
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Hussein SMI, Elbaz J, Nagy AA. Genome damage in induced pluripotent stem cells: Assessing the mechanisms and their consequences. Bioessays 2012; 35:152-62. [DOI: 10.1002/bies.201200114] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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49
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Microhomology directs diverse DNA break repair pathways and chromosomal translocations. PLoS Genet 2012; 8:e1003026. [PMID: 23144625 PMCID: PMC3493447 DOI: 10.1371/journal.pgen.1003026] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 08/24/2012] [Indexed: 11/23/2022] Open
Abstract
Chromosomal structural change triggers carcinogenesis and the formation of other genetic diseases. The breakpoint junctions of these rearrangements often contain small overlapping sequences called “microhomology,” yet the genetic pathway(s) responsible have yet to be defined. We report a simple genetic system to detect microhomology-mediated repair (MHMR) events after a DNA double-strand break (DSB) in budding yeast cells. MHMR using >15 bp operates as a single-strand annealing variant, requiring the non-essential DNA polymerase subunit Pol32. MHMR is inhibited by sequence mismatches, but independent of extensive DNA synthesis like break-induced replication. However, MHMR using less than 14 bp is genetically distinct from that using longer microhomology and far less efficient for the repair of distant DSBs. MHMR catalyzes chromosomal translocation almost as efficiently as intra-chromosomal repair. The results suggest that the intrinsic annealing propensity between microhomology sequences efficiently leads to chromosomal rearrangements. Cancer results from an accumulation of mutations that transform a normal cell into one that proliferates uncontrollably. DNA double-strand breaks (DSBs) can lead to genetic mutations and chromosome rearrangements, underscoring the importance of functional DNA DSB repair pathways in the maintenance of chromosome integrity and tumor suppression. Ample evidence suggests that cells possess multiple DSB repair mechanisms with distinct mutational potentials, and one or more of these pathways is likely responsible for the formation of chromosomal translocations. Importantly, at the junctions of many rearrangements, small (2–20 bp in length) overlapping sequences from each of the original sequences, termed “microhomology,” are found, and they may provide a clue as to how these rearrangements form. Here, we describe our genetic investigation into how flanking microhomology influences the type and frequency of DSB repair. We also show that microhomology-mediated repair (MHMR) efficiently induces chromosomal translocations. This research provides a basic understanding of the mechanisms that utilize microhomology for mutagenic repair.
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McCurley N, Hirano M, Das S, Cooper MD. Immune related genes underpin the evolution of adaptive immunity in jawless vertebrates. Curr Genomics 2012; 13:86-94. [PMID: 23024600 PMCID: PMC3308329 DOI: 10.2174/138920212799860670] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 11/30/2011] [Accepted: 12/05/2011] [Indexed: 12/17/2022] Open
Abstract
The study of immune related genes in lampreys and hagfish provides a unique perspective on the evolutionary genetic underpinnings of adaptive immunity and the evolution of vertebrate genomes. Separated from their jawed cousins at the stem of the vertebrate lineage, these jawless vertebrates have many of the gene families and gene regulatory networks associated with the defining morphological and physiological features of vertebrates. These include genes vital for innate immunity, inflammation, wound healing, protein degradation, and the development, signaling and trafficking of lymphocytes. Jawless vertebrates recognize antigen by using leucine-rich repeat (LRR) based variable lymphocyte receptors (VLRs), which are very different from the immunoglobulin (Ig) based T cell receptor (TCR) and B cell receptor (BCR) used for antigen recognition by jawed vertebrates. The somatically constructed VLR genes are expressed in monoallelic fashion by T-like and B-like lymphocytes. Jawless and jawed vertebrates thus share many of the genes that provide the molecular infrastructure and physiological context for adaptive immune responses, yet use entirely different genes and mechanisms of combinatorial assembly to generate diverse repertoires of antigen recognition receptors.
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Affiliation(s)
- Nathanael McCurley
- Emory Vaccine Center and Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, USA
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