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Wu H, Han BW, Liu T, Zhang M, Wu Y, Nie J. Epstein-Barr virus deubiquitinating enzyme BPLF1 is involved in EBV carcinogenesis by affecting cellular genomic stability. Neoplasia 2024; 55:101012. [PMID: 38875930 PMCID: PMC11225014 DOI: 10.1016/j.neo.2024.101012] [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: 12/22/2023] [Revised: 05/20/2024] [Accepted: 05/29/2024] [Indexed: 06/16/2024]
Abstract
Increased mutational burden and EBV load have been revealed from normal tissues to Epstein-Barr virus (EBV)-associated gastric carcinomas (EBVaGCs). BPLF1, encoded by EBV, is a lytic cycle protein with deubiquitinating activity has been found to participate in disrupting repair of DNA damage. We first confirmed that BPLF1 gene in gastric cancer (GC) significantly increased the DNA double strand breaks (DSBs). Ubiquitination mass spectrometry identified histones as BPLF1 interactors and potential substrates, and co-immunoprecipitation and in vitro experiments verified that BPLF1 regulates H2Bub by targeting Rad6. Over-expressing Rad6 restored H2Bub but partially reduced γ-H2AX, suggesting that other downstream DNA repair processes were affected. mRNA expression of BRCA2 were significantly down-regulated by next-generation sequencing after over-expression of BPLF1, and over-expression of p65 facilitated the repair of DSBs. We demonstrated BPLF1 may lead to the accumulation of DSBs by two pathways, reducing H2B ubiquitination (H2Bub) and blocking homologous recombination which may provide new ideas for the treatment of gastric cancer.
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Affiliation(s)
- Hantao Wu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, PR China; Key Laboratory of Antibody Engineering of Guangdong Higher Education Institutes, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Bo-Wei Han
- Key Laboratory of Antibody Engineering of Guangdong Higher Education Institutes, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Tiancai Liu
- Key Laboratory of Antibody Engineering of Guangdong Higher Education Institutes, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Min Zhang
- Key Laboratory of Antibody Engineering of Guangdong Higher Education Institutes, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Yingsong Wu
- Key Laboratory of Antibody Engineering of Guangdong Higher Education Institutes, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Jing Nie
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, PR China.
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Brovkina MV, Chapman MA, Holding ML, Clowney EJ. Emergence and influence of sequence bias in evolutionarily malleable, mammalian tandem arrays. BMC Biol 2023; 21:179. [PMID: 37612705 PMCID: PMC10463633 DOI: 10.1186/s12915-023-01673-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/01/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND The radiation of mammals at the extinction of the dinosaurs produced a plethora of new forms-as diverse as bats, dolphins, and elephants-in only 10-20 million years. Behind the scenes, adaptation to new niches is accompanied by extensive innovation in large families of genes that allow animals to contact the environment, including chemosensors, xenobiotic enzymes, and immune and barrier proteins. Genes in these "outward-looking" families are allelically diverse among humans and exhibit tissue-specific and sometimes stochastic expression. RESULTS Here, we show that these tandem arrays of outward-looking genes occupy AT-biased isochores and comprise the "tissue-specific" gene class that lack CpG islands in their promoters. Models of mammalian genome evolution have not incorporated the sharply different functions and transcriptional patterns of genes in AT- versus GC-biased regions. To examine the relationship between gene family expansion, sequence content, and allelic diversity, we use population genetic data and comparative analysis. First, we find that AT bias can emerge during evolutionary expansion of gene families in cis. Second, human genes in AT-biased isochores or with GC-poor promoters experience relatively low rates of de novo point mutation today but are enriched for non-synonymous variants. Finally, we find that isochores containing gene clusters exhibit low rates of recombination. CONCLUSIONS Our analyses suggest that tolerance of non-synonymous variation and low recombination are two forces that have produced the depletion of GC bases in outward-facing gene arrays. In turn, high AT content exerts a profound effect on their chromatin organization and transcriptional regulation.
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Affiliation(s)
- Margarita V Brovkina
- Graduate Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Margaret A Chapman
- Neurosciences Graduate Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - E Josephine Clowney
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
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DNA Polymerase Theta Plays a Critical Role in Pancreatic Cancer Development and Metastasis. Cancers (Basel) 2022; 14:cancers14174077. [PMID: 36077614 PMCID: PMC9454495 DOI: 10.3390/cancers14174077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC), due to its genomic heterogeneity and lack of effective treatment, despite decades of intensive research, will become the second leading cause of cancer-related deaths by 2030. Step-wise acquisition of mutations, due to genomic instability, is considered to drive the development of PDAC; the KRAS mutation occurs in 95 to 100% of human PDAC, and is already detectable in early premalignant lesions designated as pancreatic intraepithelial neoplasia (PanIN). This mutation is possibly the key event leading to genomic instability and PDAC development. Our study aimed to investigate the role of the error-prone DNA double-strand breaks (DSBs) repair pathway, alt-EJ, in the presence of the KRAS G12D mutation in pancreatic cancer development. Our findings show that oncogenic KRAS contributes to increasing the expression of Polθ, Lig3, and Mre11, key components of alt-EJ in both mouse and human PDAC models. We further confirm increased catalytic activity of alt-EJ in a mouse and human model of PDAC bearing the KRAS G12D mutation. Subsequently, we focused on estimating the impact of alt-EJ inactivation by polymerase theta (Polθ) deletion on pancreatic cancer development, and survival in genetically engineered mouse models (GEMMs) and cancer patients. Here, we show that even though Polθ deficiency does not fully prevent the development of pancreatic cancer, it significantly delays the onset of PanIN formation, prolongs the overall survival of experimental mice, and correlates with the overall survival of pancreatic cancer patients in the TCGA database. Our study clearly demonstrates the role of alt-EJ in the development of PDAC, and alt-EJ may be an attractive therapeutic target for pancreatic cancer patients.
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Aguado J, Gómez-Inclán C, Leeson HC, Lavin MF, Shiloh Y, Wolvetang EJ. The hallmarks of aging in Ataxia-Telangiectasia. Ageing Res Rev 2022; 79:101653. [PMID: 35644374 DOI: 10.1016/j.arr.2022.101653] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/28/2022] [Accepted: 05/24/2022] [Indexed: 01/10/2023]
Abstract
Ataxia-telangiectasia (A-T) is caused by absence of the catalytic activity of ATM, a protein kinase that plays a central role in the DNA damage response, many branches of cellular metabolism, redox and mitochondrial homeostasis, and cell cycle regulation. A-T is a complex disorder characterized mainly by progressive cerebellar degeneration, immunodeficiency, radiation sensitivity, genome instability, and predisposition to cancer. It is increasingly recognized that the premature aging component of A-T is an important driver of this disease, and A-T is therefore an attractive model to study the aging process. This review outlines the current state of knowledge pertaining to the molecular and cellular signatures of aging in A-T and proposes how these new insights can guide novel therapeutic approaches for A-T.
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Affiliation(s)
- Julio Aguado
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland 4072, Australia.
| | - Cecilia Gómez-Inclán
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland 4072, Australia
| | - Hannah C Leeson
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland 4072, Australia
| | - Martin F Lavin
- University of Queensland Centre for Clinical Research, The University of Queensland, Herston, Brisbane, Australia
| | - Yosef Shiloh
- The David and Inez Myers Laboratory of Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University School of Medicine, Tel Aviv, Israel
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Queensland 4072, Australia.
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Tang X, Chen Y, Zhu X, Miao Y, Wang D, Zhang J, Li R, Zhang L, Chen J. Alternariol monomethyl ether toxicity and genotoxicity in male Sprague-Dawley rats: 28-Day in vivo multi-endpoint assessment. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 873:503435. [PMID: 35094809 DOI: 10.1016/j.mrgentox.2021.503435] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 01/08/2023]
Abstract
Alternariol monomethyl ether (AME), a typical Alternaria toxin, has often been detected in grains. We have measured the general toxicity and genotoxicity of AME with a 28-day multi-endpoint (Pig-a assay + in vivo micronucleus [MN] test + comet assay) platform. Male Sprague-Dawley rats were administered AME (1.84, 3.67, or 7.35 μg/kg body weight/day), N-Ethyl-N-nitrosourea (40 mg/kg body weight/day), or corn oil by gavage for 28 consecutive days. Another group (AME-high-dose + recovery) was maintained for a further 14 days after the end of the AME administration. Hematology and serum biochemistry results suggested that AME might compromise the immune system. The histopathology results indicated that AME can cause liver (inflammatory cell infiltration, steatosis, and edema), kidney (renal glomerular atrophy), and spleen (white pulp atrophy) damage. The genotoxicity results showed that AME can induce gene mutations, chromosome breakage, and DNA damage, but the effects were diminished after the recovery period. According to point-of-departure analysis (BMDL10), the risk to the population of exposure to AME cannot be ignored and further assessment is needed.
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Affiliation(s)
- Xinyao Tang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Yiyi Chen
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Chenghua Center for Disease Control and Prevention, Chengdu, Sichuan, China.
| | - Xia Zhu
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Yeqiu Miao
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Dongxia Wang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Jing Zhang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Ruirui Li
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Lishi Zhang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
| | - Jinyao Chen
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China; Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, Sichuan, China.
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Shiloh Y. The cerebellar degeneration in ataxia-telangiectasia: A case for genome instability. DNA Repair (Amst) 2020; 95:102950. [PMID: 32871349 DOI: 10.1016/j.dnarep.2020.102950] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/05/2020] [Accepted: 08/08/2020] [Indexed: 02/06/2023]
Abstract
Research on the molecular pathology of genome instability disorders has advanced our understanding of the complex mechanisms that safeguard genome stability and cellular homeostasis at large. Once the culprit genes and their protein products are identified, an ongoing dialogue develops between the research lab and the clinic in an effort to link specific disease symptoms to the functions of the proteins that are missing in the patients. Ataxi A-T elangiectasia (A-T) is a prominent example of this process. A-T's hallmarks are progressive cerebellar degeneration, immunodeficiency, chronic lung disease, cancer predisposition, endocrine abnormalities, segmental premature aging, chromosomal instability and radiation sensitivity. The disease is caused by absence of the powerful protein kinase, ATM, best known as the mobilizer of the broad signaling network induced by double-strand breaks (DSBs) in the DNA. In parallel, ATM also functions in the maintenance of the cellular redox balance, mitochondrial function and turnover and many other metabolic circuits. An ongoing discussion in the A-T field revolves around the question of which ATM function is the one whose absence is responsible for the most debilitating aspect of A-T - the cerebellar degeneration. This review suggests that it is the absence of a comprehensive role of ATM in responding to ongoing DNA damage induced mainly by endogenous agents. It is the ensuing deterioration and eventual loss of cerebellar Purkinje cells, which are very vulnerable to ATM absence due to a unique combination of physiological features, which kindles the cerebellar decay in A-T.
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Affiliation(s)
- Yosef Shiloh
- The David and Inez Myers Laboratory for Cancer Genetics, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University Medical School, Tel Aviv, 69978, Israel.
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XRN2 Links RNA:DNA Hybrid Resolution to Double Strand Break Repair Pathway Choice. Cancers (Basel) 2020; 12:cancers12071821. [PMID: 32645903 PMCID: PMC7408924 DOI: 10.3390/cancers12071821] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/02/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022] Open
Abstract
It was recently shown that the 5’ to 3’ exoribonuclease XRN2 is involved in the DNA damage response. Importantly, loss of XRN2 abrogates DNA double stranded break repair via the non-homologous end-joining pathway. However, the mechanistic details of how XRN2 functions in the non-homologous end-joining repair process are unknown. In this study, we elucidated that XRN2-mediated RNA:DNA hybrid resolution is required to allow Ku70 binding to DNA ends. These data suggest that XRN2 is required for the initiation of non-homologous end-joining repair. Interestingly, we uncovered a role for XRN2 in the homologous recombination repair pathway. Loss of XRN2 lead to a decrease in the repair of double strand breaks by homologous recombination. Strikingly, when we removed RNA:DNA hybrids by RNaseH1 over-expression, homologous recombination was not restored. We found RNA:DNA hybrid formation at and downstream of the DSB site, suggesting that unregulated transcription inhibits homologous recombination repair. In summary, our results indicate a relation between RNA:DNA hybrid resolution and double strand break repair pathway choice.
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Non-canonical DNA/RNA structures during Transcription-Coupled Double-Strand Break Repair: Roadblocks or Bona fide repair intermediates? DNA Repair (Amst) 2019; 81:102661. [PMID: 31331819 DOI: 10.1016/j.dnarep.2019.102661] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Although long overlooked, it is now well understood that DNA does not systematically assemble into a canonical double helix, known as B-DNA, throughout the entire genome but can also accommodate other structures including DNA hairpins, G-quadruplexes and RNA:DNA hybrids. Notably, these non-canonical DNA structures form preferentially at transcriptionally active loci. Acting as replication roadblocks and being targeted by multiple machineries, these structures weaken the genome and render it prone to damage, including DNA double-strand breaks (DSB). In addition, secondary structures also further accumulate upon DSB formation. Here we discuss the potential functions of pre-existing or de novo formed nucleic acid structures, as bona fide repair intermediates or repair roadblocks, especially during Transcription-Coupled DNA Double-Strand Break repair (TC-DSBR), and provide an update on the specialized protein complexes displaying the ability to remove these structures to safeguard genome integrity.
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