1
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Ubhi T, Zaslaver O, Quaile AT, Plenker D, Cao P, Pham NA, Békési A, Jang GH, O'Kane GM, Notta F, Moffat J, Wilson JM, Gallinger S, Vértessy BG, Tuveson DA, Röst HL, Brown GW. Cytidine deaminases APOBEC3C and APOBEC3D promote DNA replication stress resistance in pancreatic cancer cells. NATURE CANCER 2024; 5:895-915. [PMID: 38448522 DOI: 10.1038/s43018-024-00742-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 02/09/2024] [Indexed: 03/08/2024]
Abstract
Gemcitabine is a potent inhibitor of DNA replication and is a mainstay therapeutic for diverse cancers, particularly pancreatic ductal adenocarcinoma (PDAC). However, most tumors remain refractory to gemcitabine therapies. Here, to define the cancer cell response to gemcitabine, we performed genome-scale CRISPR-Cas9 chemical-genetic screens in PDAC cells and found selective loss of cell fitness upon disruption of the cytidine deaminases APOBEC3C and APOBEC3D. Following gemcitabine treatment, APOBEC3C and APOBEC3D promote DNA replication stress resistance and cell survival by deaminating cytidines in the nuclear genome to ensure DNA replication fork restart and repair in PDAC cells. We provide evidence that the chemical-genetic interaction between APOBEC3C or APOBEC3D and gemcitabine is absent in nontransformed cells but is recapitulated across different PDAC cell lines, in PDAC organoids and in PDAC xenografts. Thus, we uncover roles for APOBEC3C and APOBEC3D in DNA replication stress resistance and offer plausible targets for improving gemcitabine-based therapies for PDAC.
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Affiliation(s)
- Tajinder Ubhi
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Olga Zaslaver
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Andrew T Quaile
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Dennis Plenker
- Lustgarten Foundation Pancreatic Cancer Research Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Xilis Inc., Durham, NC, USA
| | - Pinjiang Cao
- Living Biobank, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Nhu-An Pham
- Living Biobank, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Angéla Békési
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, BME Budapest University of Technology and Economics, Budapest, Hungary
- Genome Metabolism Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Hungarian Research Network, Budapest, Hungary
| | - Gun-Ho Jang
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Grainne M O'Kane
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
- Wallace McCain Centre for Pancreatic Cancer, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Faiyaz Notta
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
- Division of Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Jason Moffat
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Julie M Wilson
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Steven Gallinger
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
- Wallace McCain Centre for Pancreatic Cancer, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Hepatobiliary/Pancreatic Surgical Oncology Program, University Health Network, Toronto, Ontario, Canada
| | - Beáta G Vértessy
- Department of Applied Biotechnology and Food Science, Faculty of Chemical Technology and Biotechnology, BME Budapest University of Technology and Economics, Budapest, Hungary
- Genome Metabolism Research Group, Institute of Molecular Life Sciences, Research Centre for Natural Sciences, Hungarian Research Network, Budapest, Hungary
| | - David A Tuveson
- Lustgarten Foundation Pancreatic Cancer Research Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Hannes L Röst
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Grant W Brown
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada.
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2
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Ghawil M, Abdulrahman F, Hadeed I, Doggah M, Zarroug S, Habeb A. Further evidence supporting the role of DUT gene in diabetes with bone marrow failure syndrome. Am J Med Genet A 2022; 188:2406-2412. [PMID: 35611808 DOI: 10.1002/ajmg.a.62771] [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: 12/05/2021] [Revised: 03/21/2022] [Accepted: 04/05/2022] [Indexed: 11/09/2022]
Abstract
In 2017, a homozygous DUT mutation was reported to cause a syndrome of diabetes and bone marrow failure. However, no further patient with this combination has been reported and the phenotype of heterozygous DUT mutation is unknown. We describe the genotype, phenotype, and post bone marrow transplantation (BMT) data of two unrelated families with this rare syndrome. Whole-exome and/or direct sequencing of the DUT gene were performed in all family members. Each family has two children presented within the first 10 years of life with thrombocytopenia, macrocytosis, with or without anemia, followed by non-autoimmune diabetes. The same homozygous missense DUT mutation, reported in 2017 (c.425A>G p.(Tyr142Cys), was detected in all affected children. The heterozygous carriers have no BM failure, one developed type 2 diabetes, and the rest have normal fasting glucose, insulin, HbA1c, and c-peptide. Multiple nevi were detected in homozygous and heterozygous mutation carriers. Allogenic BMT normalized BM aplasia without impact on diabetes. Post BMT follow-up revealed normal puberty and school performance; but three have height <2.5 SDS. We add two families with this syndrome supporting a role of DUT in bone marrow and β-cell function. The heterozygous carriers of this DUT mutation appear to be healthy.
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Affiliation(s)
- Millad Ghawil
- Pediatric Department, Endocrine Division, Tripoli University Hospital, Faculty of Medicine, University of Tripoli, Tripoli, Libya
| | - Fathia Abdulrahman
- Pediatric Department, Hematology Division, Tripoli University Hospital, Faculty of Medicine, University of Tripoli, Tripoli, Libya
| | - Ibtisam Hadeed
- Pediatric Department, Endocrine Division, Tripoli University Hospital, Faculty of Medicine, University of Tripoli, Tripoli, Libya
| | - Milad Doggah
- Pediatric Department, Endocrine Division, Tripoli University Hospital, Faculty of Medicine, University of Tripoli, Tripoli, Libya
| | - Salem Zarroug
- Pediatric Department, Hematology Division, Tripoli University Hospital, Faculty of Medicine, University of Tripoli, Tripoli, Libya
| | - Abdelhadi Habeb
- Pediatric Department, Prince Mohamed bin Abdulaziz Hospital, National Guard Ministry, Madinah, Saudi Arabia
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3
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Jiang L, Yin J, Qian M, Rong S, Zhang S, Chen K, Zhao C, Tan Y, Guo J, Chen H, Gao S, Liu T, Liu Y, Shen B, Yang J, Zhang Y, Meng FL, Hu J, Ma H, Chen YH. UdgX-Mediated Uracil Sequencing at Single-Nucleotide Resolution. J Am Chem Soc 2022; 144:1323-1331. [PMID: 35037455 DOI: 10.1021/jacs.1c11269] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
As an aberrant base in DNA, uracil is generated by either deoxyuridine (dU) misincorporation or cytosine deamination, and involved in multiple physiological and pathological processes. Genome-wide profiles of uracil are important for study of these processes. Current methods for whole-genome mapping of uracil all rely on uracil-DNA N-glycosylase (UNG) and are limited in resolution, specificity, and/or sensitivity. Here, we developed a UdgX cross-linking and polymerase stalling sequencing ("Ucaps-seq") method to detect dU at single-nucleotide resolution. First, the specificity of Ucaps-seq was confirmed on synthetic DNA. Then the effectiveness of the approach was verified on two genomes from different sources. Ucaps-seq not only identified the enrichment of dU at dT sites in pemetrexed-treated cancer cells with globally elevated uracil but also detected dU at dC sites within the "WRC" motif in activated B cells which have increased dU in specific regions. Finally, Ucaps-seq was utilized to detect dU introduced by the cytosine base editor (nCas9-APOBEC) and identified a novel off-target site in cellular context. In conclusion, Ucaps-seq is a powerful tool with many potential applications, especially in evaluation of base editing fidelity.
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Affiliation(s)
- Liudan Jiang
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Shanghai Fifth People's Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Jiayong Yin
- Institute of Pediatrics and Department of Hematology and Oncology, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Maoxiang Qian
- Institute of Pediatrics and Department of Hematology and Oncology, Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Shaoqin Rong
- Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Shengqi Zhang
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Kejing Chen
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Chengchen Zhao
- School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Yuanqing Tan
- Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Jiayin Guo
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Hao Chen
- School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China
| | - Siyun Gao
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Tingting Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yi Liu
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Bin Shen
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
| | - Jian Yang
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
| | - Yong Zhang
- School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Fei-Long Meng
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinchuan Hu
- Shanghai Fifth People's Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Honghui Ma
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
- Research Units of Origin and Regulation of Heart Rhythm, Chinese Academy of Medical Sciences, Shanghai 200092, China
| | - Yi-Han Chen
- Department of Cardiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, 200092, China
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4
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Zhou D, Lv X, Wang Y, Liu H, Luo S, Li W, Huang G. Folic acid alleviates age-related cognitive decline and inhibits apoptosis of neurocytes in senescence-accelerated mouse prone 8: deoxythymidine triphosphate biosynthesis as a potential mechanism. J Nutr Biochem 2021; 97:108796. [PMID: 34102282 DOI: 10.1016/j.jnutbio.2021.108796] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 03/28/2021] [Accepted: 05/31/2021] [Indexed: 11/18/2022]
Abstract
Disturbed deoxythymidine triphosphate biosynthesis due to the inhibition of thymidylate synthase (TS) can lead to uracil accumulation in DNA, eventually, lead to neurocytes apoptosis and cognitive decline. Folic acid supplementation delayed cognitive decline and neurodegeneration in senescence-accelerated mouse prone 8 (SAMP8). Whether folic acid, one of nutrition factor, the effect on the expression of TS is unknown. The study aimed to determine if folic acid supplementation could alleviate age-related cognitive decline and apoptosis of neurocytes by increasing TS expression in SAMP8 mice. According to folic acid concentration in diet, four-month-old male SAMP8 mice were randomly divided into three different diet groups by baseline body weight in equal numbers. Moreover, to evaluate the role of TS, a TS inhibitor was injected intraperitoneal. Cognitive test, apoptosis rates of neurocytes, expression of TS, relative uracil level in telomere, and telomere length in brain tissue were detected. The results showed that folic acid supplementation decreased deoxyuridine monophosphate accumulation, uracil misincorporation in telomere, alleviated telomere length shorting, increased expression of TS, then decreased apoptosis rates of neurocytes, and alleviated cognitive performance in SAMP8 mice. Moreover, at the same concentration of folic acid, TS inhibitor raltitrexed increased deoxyuridine monophosphate accumulation, uracil misincorporation in telomere, and exacerbated telomere length shorting, decreased expression of TS, then increased apoptosis rates of neurocytes, and decreased cognitive performance in SAMP8 mice. In conclusion, folic acid supplementation alleviated age-related cognitive decline and inhibited apoptosis of neurocytes by increasing TS expression in SAMP8 mice.
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Affiliation(s)
- Dezheng Zhou
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Xin Lv
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Yalan Wang
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Huan Liu
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China
| | - Suhui Luo
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China
| | - Wen Li
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.
| | - Guowei Huang
- Department of Nutrition and Food Science, School of Public Health, Tianjin Medical University, Tianjin, China; Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.
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5
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Fiddler JL, Xiu Y, Blum JE, Lamarre SG, Phinney WN, Stabler SP, Brosnan ME, Brosnan JT, Thalacker-Mercer AE, Field MS. Reduced Shmt2 Expression Impairs Mitochondrial Folate Accumulation and Respiration, and Leads to Uracil Accumulation in Mouse Mitochondrial DNA. J Nutr 2021; 151:2882-2893. [PMID: 34383924 DOI: 10.1093/jn/nxab211] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/24/2021] [Accepted: 06/08/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Adequate cellular thymidylate (dTMP) pools are essential for preservation of nuclear and mitochondrial genome stability. Previous studies have indicated that disruption in nuclear dTMP synthesis leads to increased uracil misincorporation into DNA, affecting genome stability. To date, the effects of impaired mitochondrial dTMP synthesis in nontransformed tissues have been understudied. OBJECTIVES This study aimed to determine the effects of decreased serine hydroxymethyltransferase 2 (Shmt2) expression and dietary folate deficiency on mitochondrial DNA (mtDNA) integrity and mitochondrial function in mouse tissues. METHODS Liver mtDNA content, and uracil content in liver mtDNA, were measured in Shmt2+/- and Shmt2+/+ mice weaned onto either a folate-sufficient control diet (2 mg/kg folic acid; C) or a modified diet lacking folic acid (0 mg/kg folic acid) for 7 wk. Shmt2+/- and Shmt2+/+ mouse embryonic fibroblast (MEF) cells were cultured in defined culture medium containing either 0 or 25 nM folate (6S-5-formyl-tetrahydrofolate, folinate) to assess proliferative capacity and mitochondrial function. Chi-square tests, linear mixed models, and 2-factor ANOVA with Tukey post hoc analyses were used to analyze data. RESULTS Shmt2 +/- mice exhibited a 48%-67% reduction in SHMT2 protein concentrations in tissues. Interestingly, Shmt2+/- mice consuming the folate-sufficient C diet exhibited a 25% reduction in total folate in liver mitochondria. There was also a >20-fold increase in uracil in liver mtDNA in Shmt2+/- mice consuming the C diet, and dietary folate deficiency also increased uracil content in mouse liver mtDNA from both Shmt2+/+ and Shmt2+/- mice. Furthermore, decreased Shmt2 expression in MEF cells reduced cell proliferation, mitochondrial membrane potential, and oxygen consumption rate. CONCLUSIONS This study demonstrates that Shmt2 heterozygosity and dietary folate deficiency impair mitochondrial dTMP synthesis in mice, as evidenced by the increased uracil in mtDNA. In addition, Shmt2 heterozygosity impairs mitochondrial function in MEF cells. These findings suggest that elevated uracil in mtDNA may impair mitochondrial function.
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Affiliation(s)
- Joanna L Fiddler
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Yuwen Xiu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Jamie E Blum
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Simon G Lamarre
- Department of Biology, University of Moncton, Moncton, New Brunswick, Canada
| | | | - Sally P Stabler
- Department of Medicine, University of Colorado, Aurora, CO, USA
| | - Margaret E Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - John T Brosnan
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Anna E Thalacker-Mercer
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Martha S Field
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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6
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Wang Y, Zhang X, Han S, Yang W, Chen Z, Wu F, Liu J, Weng X, Zhou X. Base-Resolution Analysis of Deoxyuridine at the Genome Scale Based on the Artificial Incorporation Modified Nucleobase. ACS CENTRAL SCIENCE 2021; 7:973-979. [PMID: 34235258 PMCID: PMC8227591 DOI: 10.1021/acscentsci.0c01504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Indexed: 05/11/2023]
Abstract
Deamination of cytosine and dUMP misincorporation have been found to be capable of producing uracil in the genome. This study presents the AI-seq (artificial incorporation modified nucleobase for sequencing), a "base substitution", which not only is capable of profiling uracil at single-nucleotide resolution and showing its centromeric enrichment but could also reveal that the identified uracil sites are derived from cytosine deamination. All the results indicate the potential biological significance of uracil as the epigenetic modification.
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Affiliation(s)
- Yafen Wang
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Xiong Zhang
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Shaoqing Han
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Wei Yang
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Zonggui Chen
- State
Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for
Seed Design, Chinese Academy of Sciences, Wuhan 430072, China
| | - Fan Wu
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Jizhou Liu
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
| | - Xiaocheng Weng
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
- E-mail:
| | - Xiang Zhou
- College
of Chemistry and Molecular Sciences, Key Laboratory of Biomedical
Polymers of Ministry of Education, Wuhan
University, Wuhan, 430072 Hubei, China
- E-mail:
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7
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Detection of Genomic Uracil Patterns. Int J Mol Sci 2021; 22:ijms22083902. [PMID: 33918885 PMCID: PMC8070346 DOI: 10.3390/ijms22083902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/28/2021] [Accepted: 04/05/2021] [Indexed: 01/06/2023] Open
Abstract
The appearance of uracil in the deoxyuridine moiety of DNA is among the most frequently occurring genomic modifications. Three different routes can result in genomic uracil, two of which do not require specific enzymes: spontaneous cytosine deamination due to the inherent chemical reactivity of living cells, and thymine-replacing incorporation upon nucleotide pool imbalances. There is also an enzymatic pathway of cytosine deamination with multiple DNA (cytosine) deaminases involved in this process. In order to describe potential roles of genomic uracil, it is of key importance to utilize efficient uracil-DNA detection methods. In this review, we provide a comprehensive and critical assessment of currently available uracil detection methods with special focus on genome-wide mapping solutions. Recent developments in PCR-based and in situ detection as well as the quantitation of genomic uracil are also discussed.
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8
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Wang B, Chen Y, Zhang X, Jiang Z, Wang Y, Chen K, Wang F, Weng X, Zhou X. A far-red emissive two-photon fluorescent probe for quantification of uracil in genomic DNA. Chem Commun (Camb) 2021; 57:2784-2787. [PMID: 33599665 DOI: 10.1039/d1cc00016k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a new method for dU detection in genomic DNA combined with UNG excision and fluorescent probe labeling. UNG can remove uracil bases to introduce abasic sites, which can react with NRNO to produce intense fluorescence because of the inhibition of the PET effect. It can also cause the polymerase extension to stop to provide details of dU site information.
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Affiliation(s)
- Bingyao Wang
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Yi Chen
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Xiong Zhang
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Zhuoran Jiang
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Yafen Wang
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Kun Chen
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Fang Wang
- Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Xiaocheng Weng
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
| | - Xiang Zhou
- The Institute of Advanced Studies, College of Chemistry and Molecular Sciences, Key Laboratory of Biomedical Polymers of Ministry of Education, Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University, Wuhan, Hubei 430072, China.
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9
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Stewart JA, Schauer G, Bhagwat AS. Visualization of uracils created by APOBEC3A using UdgX shows colocalization with RPA at stalled replication forks. Nucleic Acids Res 2020; 48:e118. [PMID: 33074285 PMCID: PMC7672425 DOI: 10.1093/nar/gkaa845] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 12/19/2022] Open
Abstract
The AID/APOBEC enzymes deaminate cytosines in single-stranded DNA (ssDNA) and play key roles in innate and adaptive immunity. The resulting uracils cause mutations and strand breaks that inactivate viruses and diversify antibody repertoire. Mutational evidence suggests that two members of this family, APOBEC3A (A3A) and APOBEC3B, deaminate cytosines in the lagging-strand template during replication. To obtain direct evidence for the presence of these uracils, we engineered a protein that covalently links to DNA at uracils, UdgX, for mammalian expression and immunohistochemistry. We show that UdgX strongly prefers uracils in ssDNA over those in U•G or U:A pairs, and localizes to nuclei in a dispersed form. When A3A is expressed in these cells, UdgX tends to form foci. The treatment of cells with cisplatin, which blocks replication, causes a significant increase in UdgX foci. Furthermore, this protein- and hence the uracils created by A3A- colocalize with replication protein A (RPA), but not with A3A. Using purified proteins, we confirm that RPA inhibits A3A by binding ssDNA, but despite its overexpression following cisplatin treatment, RPA is unable to fully protect ssDNA created by cisplatin adducts. This suggests that cisplatin treatment of cells expressing APOBEC3A should cause accumulation of APOBEC signature mutations.
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Affiliation(s)
- Jessica A Stewart
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - Grant Schauer
- Department of Biochemistry & Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Ashok S Bhagwat
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.,Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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10
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Pálinkás HL, Békési A, Róna G, Pongor L, Papp G, Tihanyi G, Holub E, Póti Á, Gemma C, Ali S, Morten MJ, Rothenberg E, Pagano M, Szűts D, Győrffy B, Vértessy BG. Genome-wide alterations of uracil distribution patterns in human DNA upon chemotherapeutic treatments. eLife 2020; 9:e60498. [PMID: 32956035 PMCID: PMC7505663 DOI: 10.7554/elife.60498] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/23/2020] [Indexed: 12/17/2022] Open
Abstract
Numerous anti-cancer drugs perturb thymidylate biosynthesis and lead to genomic uracil incorporation contributing to their antiproliferative effect. Still, it is not yet characterized if uracil incorporations have any positional preference. Here, we aimed to uncover genome-wide alterations in uracil pattern upon drug treatments in human cancer cell line models derived from HCT116. We developed a straightforward U-DNA sequencing method (U-DNA-Seq) that was combined with in situ super-resolution imaging. Using a novel robust analysis pipeline, we found broad regions with elevated probability of uracil occurrence both in treated and non-treated cells. Correlation with chromatin markers and other genomic features shows that non-treated cells possess uracil in the late replicating constitutive heterochromatic regions, while drug treatment induced a shift of incorporated uracil towards segments that are normally more active/functional. Data were corroborated by colocalization studies via dSTORM microscopy. This approach can be applied to study the dynamic spatio-temporal nature of genomic uracil.
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Affiliation(s)
- Hajnalka L Pálinkás
- Genome Metabolism Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
- Doctoral School of Multidisciplinary Medical Science, University of SzegedSzegedHungary
| | - Angéla Békési
- Genome Metabolism Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
| | - Gergely Róna
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
- Department of Biochemistry and Molecular Pharmacology, New York University School of MedicineNew YorkUnited States
- Perlmutter Cancer Center, New York University School of MedicineNew YorkUnited States
- Howard Hughes Medical Institute, New York University School of MedicineNew YorkUnited States
| | - Lőrinc Pongor
- Cancer Biomarker Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Bioinformatics and 2nd Department of Pediatrics, Semmelweis UniversityBudapestHungary
| | - Gábor Papp
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
| | - Gergely Tihanyi
- Genome Metabolism Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
| | - Eszter Holub
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
| | - Ádám Póti
- Genome Stability Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Carolina Gemma
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital CampusLondonUnited Kingdom
| | - Simak Ali
- Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital CampusLondonUnited Kingdom
| | - Michael J Morten
- Department of Biochemistry and Molecular Pharmacology, New York University School of MedicineNew YorkUnited States
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of MedicineNew YorkUnited States
| | - Michele Pagano
- Department of Biochemistry and Molecular Pharmacology, New York University School of MedicineNew YorkUnited States
- Perlmutter Cancer Center, New York University School of MedicineNew YorkUnited States
- Howard Hughes Medical Institute, New York University School of MedicineNew YorkUnited States
| | - Dávid Szűts
- Genome Stability Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
| | - Balázs Győrffy
- Cancer Biomarker Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Bioinformatics and 2nd Department of Pediatrics, Semmelweis UniversityBudapestHungary
| | - Beáta G Vértessy
- Genome Metabolism Research Group, Institute of Enzymology, Research Centre for Natural SciencesBudapestHungary
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and EconomicsBudapestHungary
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11
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Martínez-Arribas B, Requena CE, Pérez-Moreno G, Ruíz-Pérez LM, Vidal AE, González-Pacanowska D. DCTPP1 prevents a mutator phenotype through the modulation of dCTP, dTTP and dUTP pools. Cell Mol Life Sci 2020; 77:1645-1660. [PMID: 31377845 PMCID: PMC7162842 DOI: 10.1007/s00018-019-03250-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/05/2019] [Accepted: 07/23/2019] [Indexed: 12/02/2022]
Abstract
To maintain dNTP pool homeostasis and preserve genetic integrity of nuclear and mitochondrial genomes, the synthesis and degradation of DNA precursors must be precisely regulated. Human all-alpha dCTP pyrophosphatase 1 (DCTPP1) is a dNTP pyrophosphatase with high affinity for dCTP and 5'-modified dCTP derivatives, but its contribution to overall nucleotide metabolism is controversial. Here, we identify a central role for DCTPP1 in the homeostasis of dCTP, dTTP and dUTP. Nucleotide pools and the dUTP/dTTP ratio are severely altered in DCTPP1-deficient cells, which exhibit an accumulation of uracil in genomic DNA, the activation of the DNA damage response and both a mitochondrial and nuclear hypermutator phenotype. Notably, DNA damage can be reverted by incubation with thymidine, dUTPase overexpression or uracil-DNA glycosylase suppression. Moreover, DCTPP1-deficient cells are highly sensitive to down-regulation of nucleoside salvage. Our data indicate that DCTPP1 is crucially involved in the provision of dCMP for thymidylate biosynthesis, introducing a new player in the regulation of pyrimidine dNTP levels and the maintenance of genomic integrity.
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Affiliation(s)
- Blanca Martínez-Arribas
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Cristina E Requena
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Guiomar Pérez-Moreno
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Luis M Ruíz-Pérez
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Antonio E Vidal
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina "López-Neyra", Consejo Superior de Investigaciones Científicas (CSIC), Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain.
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12
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Qian C, Wang R, Wu H, Zhang F, Wu J, Wang L. Uracil-Mediated New Photospacer-Adjacent Motif of Cas12a To Realize Visualized DNA Detection at the Single-Copy Level Free from Contamination. Anal Chem 2019; 91:11362-11366. [DOI: 10.1021/acs.analchem.9b02554] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Cheng Qian
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Rui Wang
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Hui Wu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Fang Zhang
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Jian Wu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Liu Wang
- Institute of Quality and Standards for Agro-products, Zhejiang Academy of Agricultural Sciences, State Key Laboratory of Quality and Safety of Agro-products, Hangzhou 310021, China
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13
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Yagüe-Capilla M, García-Caballero D, Aguilar-Pereyra F, Castillo-Acosta VM, Ruiz-Pérez LM, Vidal AE, González-Pacanowska D. Base excision repair plays an important role in the protection against nitric oxide- and in vivo-induced DNA damage in Trypanosoma brucei. Free Radic Biol Med 2019; 131:59-71. [PMID: 30472364 DOI: 10.1016/j.freeradbiomed.2018.11.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 10/22/2018] [Accepted: 11/21/2018] [Indexed: 11/17/2022]
Abstract
Uracil-DNA glycosylase (UNG) initiates the base excision repair pathway by excising uracil from DNA. We have previously shown that Trypanosoma brucei cells defective in UNG exhibit reduced infectivity thus demonstrating the relevance of this glycosylase for survival within the mammalian host. In the early steps of the immune response, nitric oxide (NO) is released by phagocytes, which in combination with oxygen radicals produce reactive nitrogen species (RNS). These species can react with DNA generating strand breaks and base modifications including deaminations. Since deaminated cytosines are the main substrate for UNG, we hypothesized that the glycosylase might confer protection towards nitrosative stress. Our work establishes the occurrence of genotoxic damage in Trypanosoma brucei upon exposure to NO in vitro and shows that deficient base excision repair results in increased levels of damage in DNA and a hypermutator phenotype. We also evaluate the incidence of DNA damage during infection in vivo and show that parasites recovered from mice exhibit higher levels of DNA strand breaks, base deamination and repair foci compared to cells cultured in vitro. Notably, the absence of UNG leads to reduced infectivity and enhanced DNA damage also in animal infections. By analysing mRNA and protein levels, we found that surviving UNG-KO trypanosomes highly express tryparedoxin peroxidase involved in trypanothione/tryparedoxin metabolism. These observations suggest that the immune response developed by the host enhances the activation of genes required to counteract oxidative stress and emphasize the importance of DNA repair pathways in the protection to genotoxic and oxidative stress in trypanosomes.
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Affiliation(s)
- Miriam Yagüe-Capilla
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Daniel García-Caballero
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Fernando Aguilar-Pereyra
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Víctor M Castillo-Acosta
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Luis M Ruiz-Pérez
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Antonio E Vidal
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina "López-Neyra". Consejo Superior de Investigaciones Científicas. Parque Tecnológico de Ciencias de la Salud, Avenida del Conocimiento, 17, 18016 Armilla, Granada, Spain.
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14
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Combinatorial Loss of the Enzymatic Activities of Viral Uracil-DNA Glycosylase and Viral dUTPase Impairs Murine Gammaherpesvirus Pathogenesis and Leads to Increased Recombination-Based Deletion in the Viral Genome. mBio 2018; 9:mBio.01831-18. [PMID: 30377280 PMCID: PMC6212821 DOI: 10.1128/mbio.01831-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Unrepaired uracils in DNA can lead to mutations and compromise genomic stability. Herpesviruses have hijacked host processes of DNA repair and nucleotide metabolism by encoding a viral UNG that excises uracils and a viral dUTPase that initiates conversion of dUTP to dTTP. To better understand the impact of these processes on gammaherpesvirus pathogenesis, we examined the separate and collaborative roles of vUNG and vDUT upon MHV68 infection of mice. Simultaneous disruption of the enzymatic activities of both vUNG and vDUT led to a severe defect in acute replication and establishment of latency, while also revealing a novel, combinatorial function in promoting viral genomic stability. We propose that herpesviruses require these enzymatic processes to protect the viral genome from damage, possibly triggered by misincorporated uracil. This reveals a novel point of therapeutic intervention to potentially block viral replication and reduce the fitness of multiple herpesviruses. Misincorporation of uracil or spontaneous cytidine deamination is a common mutagenic insult to DNA. Herpesviruses encode a viral uracil-DNA glycosylase (vUNG) and a viral dUTPase (vDUT), each with enzymatic and nonenzymatic functions. However, the coordinated roles of these enzymatic activities in gammaherpesvirus pathogenesis and viral genomic stability have not been defined. In addition, potential compensation by the host UNG has not been examined in vivo. The genetic tractability of the murine gammaherpesvirus 68 (MHV68) system enabled us to delineate the contribution of host and viral factors that prevent uracilated DNA. Recombinant MHV68 lacking vUNG (ORF46.stop) was not further impaired for acute replication in the lungs of UNG−/− mice compared to wild-type (WT) mice, indicating host UNG does not compensate for the absence of vUNG. Next, we investigated the separate and combinatorial consequences of mutating the catalytic residues of the vUNG (ORF46.CM) and vDUT (ORF54.CM). ORF46.CM was not impaired for replication, while ORF54.CM had a slight transient defect in replication in the lungs. However, disabling both vUNG and vDUT led to a significant defect in acute expansion in the lungs, followed by impaired establishment of latency in the splenic reservoir. Upon serial passage of the ORF46.CM/ORF54.CM mutant in either fibroblasts or the lungs of mice, we noted rapid loss of the nonessential yellow fluorescent protein (YFP) reporter gene from the viral genome, due to recombination at repetitive elements. Taken together, our data indicate that the vUNG and vDUT coordinate to promote viral genomic stability and enable viral expansion prior to colonization of latent reservoirs.
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15
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The etiology of uracil residues in the Saccharomyces cerevisiae genomic DNA. Curr Genet 2018; 65:393-399. [PMID: 30328489 PMCID: PMC6420880 DOI: 10.1007/s00294-018-0895-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/11/2018] [Accepted: 10/13/2018] [Indexed: 11/29/2022]
Abstract
Non-canonical residue in DNA is a major and conserved source of genome instability. The appearance of uracil residues in DNA accompanies a significant mutagenic consequence and is regulated at multiple levels, from the concentration of available dUTP in the nucleotide pool to the excision repair for removal from DNA. Recently, an interesting phenomenon of transcription-associated elevation in uracil-derived mutations was described in Saccharomyces cerevisiae genome. While trying to understand the variability in mutagenesis, we uncovered that the frequency of uracil incorporation into DNA can vary depending on the transcription rate and that the non-replicative, repair-associated DNA synthesis underlies the higher uracil density of the actively transcribed genomic loci. This novel mechanism brings together the chemical vulnerability of DNA under transcription and the uracil-associated mutagenesis, and has the potential to apply to other non-canonical residues of mutagenic importance.
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16
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Genome-wide mapping reveals that deoxyuridine is enriched in the human centromeric DNA. Nat Chem Biol 2018; 14:680-687. [PMID: 29785056 DOI: 10.1038/s41589-018-0065-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 03/19/2018] [Indexed: 02/06/2023]
Abstract
Uracil in DNA can be generated by cytosine deamination or dUMP misincorporation; however, its distribution in the human genome is poorly understood. Here we present a selective labeling and pull-down technology for genome-wide uracil profiling and identify thousands of uracil peaks in three different human cell lines. Surprisingly, uracil is highly enriched at the centromere of the human genome. Using mass spectrometry, we demonstrate that human centromeric DNA contains a higher level of uracil. We also directly verify the presence of uracil within two centromeric uracil peaks on chromosomes 6 and 11. Moreover, centromeric uracil is preferentially localized within the binding regions of the centromere-specific histone CENP-A and can be excised by human uracil-DNA glycosylase UNG. Collectively, our approaches allow comprehensive analysis of uracil in the human genome and provide robust tools for mapping and future functional studies of uracil in DNA.
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17
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Hirmondo R, Lopata A, Suranyi EV, Vertessy BG, Toth J. Differential control of dNTP biosynthesis and genome integrity maintenance by the dUTPase superfamily enzymes. Sci Rep 2017; 7:6043. [PMID: 28729658 PMCID: PMC5519681 DOI: 10.1038/s41598-017-06206-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 06/12/2017] [Indexed: 01/22/2023] Open
Abstract
dUTPase superfamily enzymes generate dUMP, the obligate precursor for de novo dTTP biosynthesis, from either dUTP (monofunctional dUTPase, Dut) or dCTP (bifunctional dCTP deaminase/dUTPase, Dcd:dut). In addition, the elimination of dUTP by these enzymes prevents harmful uracil incorporation into DNA. These two beneficial outcomes have been thought to be related. Here we determined the relationship between dTTP biosynthesis (dTTP/dCTP balance) and the prevention of DNA uracilation in a mycobacterial model that encodes both the Dut and Dcd:dut enzymes, and has no other ways to produce dUMP. We show that, in dut mutant mycobacteria, the dTTP/dCTP balance remained unchanged, but the uracil content of DNA increased in parallel with the in vitro activity-loss of Dut accompanied with a considerable increase in the mutation rate. Conversely, dcd:dut inactivation resulted in perturbed dTTP/dCTP balance and two-fold increased mutation rate, but did not increase the uracil content of DNA. Thus, unexpectedly, the regulation of dNTP balance and the prevention of DNA uracilation are decoupled and separately brought about by the Dcd:dut and Dut enzymes, respectively. Available evidence suggests that the discovered functional separation is conserved in humans and other organisms.
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Affiliation(s)
- Rita Hirmondo
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Anna Lopata
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Eva Viola Suranyi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
- Department of Applied Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Beata G Vertessy
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
- Department of Applied Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
| | - Judit Toth
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary.
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18
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Wang Q, Kieffer-Kwon KR, Oliveira TY, Mayer CT, Yao K, Pai J, Cao Z, Dose M, Casellas R, Jankovic M, Nussenzweig MC, Robbiani DF. The cell cycle restricts activation-induced cytidine deaminase activity to early G1. J Exp Med 2016; 214:49-58. [PMID: 27998928 PMCID: PMC5206505 DOI: 10.1084/jem.20161649] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 10/21/2016] [Accepted: 11/22/2016] [Indexed: 02/02/2023] Open
Abstract
Wang et al. show that antibody gene deamination by activation-induced cytidine deaminase (AID) is restricted to a short time window in early G1 as a result of AID’s transient nuclear localization and accessibility of the target sites. Activation-induced cytidine deaminase (AID) converts cytosine into uracil to initiate somatic hypermutation (SHM) and class switch recombination (CSR) of antibody genes. In addition, this enzyme produces DNA lesions at off-target sites that lead to mutations and chromosome translocations. However, AID is mostly cytoplasmic, and how and exactly when it accesses nuclear DNA remains enigmatic. Here, we show that AID is transiently in spatial contact with genomic DNA from the time the nuclear membrane breaks down in prometaphase until early G1, when it is actively exported into the cytoplasm. Consistent with this observation, the immunoglobulin (Igh) gene deamination as measured by uracil accumulation occurs primarily in early G1 after chromosomes decondense. Altering the timing of cell cycle–regulated AID nuclear residence increases DNA damage at off-target sites. Thus, the cell cycle–controlled breakdown and reassembly of the nuclear membrane and the restoration of transcription after mitosis constitute an essential time window for AID-induced deamination, and provide a novel DNA damage mechanism restricted to early G1.
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Affiliation(s)
- Qiao Wang
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Kyong-Rim Kieffer-Kwon
- Genomics and Immunity, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892.,Center of Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Thiago Y Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Christian T Mayer
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Kaihui Yao
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Joy Pai
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Zhen Cao
- Weill Cornell Medical College and Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Marei Dose
- Genomics and Immunity, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892.,Center of Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Rafael Casellas
- Genomics and Immunity, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892.,Center of Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Mila Jankovic
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
| | - Michel C Nussenzweig
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065 .,Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065
| | - Davide F Robbiani
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065
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19
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The nucleotidohydrolases DCTPP1 and dUTPase are involved in the cellular response to decitabine. Biochem J 2016; 473:2635-43. [PMID: 27325794 DOI: 10.1042/bcj20160302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/17/2016] [Indexed: 02/03/2023]
Abstract
Decitabine (5-aza-2'-deoxycytidine, aza-dCyd) is an anti-cancer drug used clinically for the treatment of myelodysplastic syndromes and acute myeloid leukaemia that can act as a DNA-demethylating or genotoxic agent in a dose-dependent manner. On the other hand, DCTPP1 (dCTP pyrophosphatase 1) and dUTPase are two 'house-cleaning' nucleotidohydrolases involved in the elimination of non-canonical nucleotides. In the present study, we show that exposure of HeLa cells to decitabine up-regulates the expression of several pyrimidine metabolic enzymes including DCTPP1, dUTPase, dCMP deaminase and thymidylate synthase, thus suggesting their contribution to the cellular response to this anti-cancer nucleoside. We present several lines of evidence supporting that, in addition to the formation of aza-dCTP (5-aza-2'-deoxycytidine-5'-triphosphate), an alternative cytotoxic mechanism for decitabine may involve the formation of aza-dUMP, a potential thymidylate synthase inhibitor. Indeed, dUTPase or DCTPP1 down-regulation enhanced the cytotoxic effect of decitabine producing an accumulation of nucleoside triphosphates containing uracil as well as uracil misincorporation and double-strand breaks in genomic DNA. Moreover, DCTPP1 hydrolyses the triphosphate form of decitabine with similar kinetic efficiency to its natural substrate dCTP and prevents decitabine-induced global DNA demethylation. The data suggest that the nucleotidohydrolases DCTPP1 and dUTPase are factors involved in the mode of action of decitabine with potential value as enzymatic targets to improve decitabine-based chemotherapy.
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20
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Róna G, Scheer I, Nagy K, Pálinkás HL, Tihanyi G, Borsos M, Békési A, Vértessy BG. Detection of uracil within DNA using a sensitive labeling method for in vitro and cellular applications. Nucleic Acids Res 2016; 44:e28. [PMID: 26429970 PMCID: PMC4756853 DOI: 10.1093/nar/gkv977] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 09/10/2015] [Accepted: 09/15/2015] [Indexed: 11/14/2022] Open
Abstract
The role of uracil in genomic DNA has been recently re-evaluated. It is now widely accepted to be a physiologically important DNA element in diverse systems from specific phages to antibody maturation and Drosophila development. Further relevant investigations would largely benefit from a novel reliable and fast method to gain quantitative and qualitative information on uracil levels in DNA both in vitro and in situ, especially since current techniques does not allow in situ cellular detection. Here, starting from a catalytically inactive uracil-DNA glycosylase protein, we have designed several uracil sensor fusion proteins. The designed constructs can be applied as molecular recognition tools that can be detected with conventional antibodies in dot-blot applications and may also serve as in situ uracil-DNA sensors in cellular techniques. Our method is verified on numerous prokaryotic and eukaryotic cellular systems. The method is easy to use and can be applied in a high-throughput manner. It does not require expensive equipment or complex know-how, facilitating its easy implementation in any basic molecular biology laboratory. Elevated genomic uracil levels from cells of diverse genetic backgrounds and/or treated with different drugs can be demonstrated also in situ, within the cell.
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Affiliation(s)
- Gergely Róna
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt Gellért Square 4, H-1111 Budapest, Hungary
| | - Ildikó Scheer
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt Gellért Square 4, H-1111 Budapest, Hungary
| | - Kinga Nagy
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt Gellért Square 4, H-1111 Budapest, Hungary
| | - Hajnalka L Pálinkás
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Doctoral School of Multidisciplinary Medical Science, University of Szeged, H-6720 Szeged, Hungary
| | - Gergely Tihanyi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt Gellért Square 4, H-1111 Budapest, Hungary
| | - Máté Borsos
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary
| | - Angéla Békési
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary
| | - Beáta G Vértessy
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Magyar Tudósok Str. 2, H-1117 Budapest, Hungary Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Szt Gellért Square 4, H-1111 Budapest, Hungary
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21
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Fachmann M, Josefsen M, Hoorfar J, Nielsen M, Löfström C. Cost-effective optimization of real-time PCR-based detection of Campylobacter
and Salmonella
with inhibitor tolerant DNA polymerases. J Appl Microbiol 2015; 119:1391-402. [DOI: 10.1111/jam.12937] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/03/2015] [Accepted: 08/11/2015] [Indexed: 11/29/2022]
Affiliation(s)
- M.S.R. Fachmann
- Division of Microbiology and Production; National Food Institute; Technical University of Denmark; Søborg Denmark
| | - M.H. Josefsen
- Division of Microbiology and Production; National Food Institute; Technical University of Denmark; Søborg Denmark
| | - J. Hoorfar
- Division of Microbiology and Production; National Food Institute; Technical University of Denmark; Søborg Denmark
| | - M.T. Nielsen
- Division of Microbiology and Production; National Food Institute; Technical University of Denmark; Søborg Denmark
| | - C. Löfström
- Division of Microbiology and Production; National Food Institute; Technical University of Denmark; Søborg Denmark
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22
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Hirmondó R, Szabó JE, Nyíri K, Tarjányi S, Dobrotka P, Tóth J, Vértessy BG. Cross-species inhibition of dUTPase via the Staphylococcal Stl protein perturbs dNTP pool and colony formation in Mycobacterium. DNA Repair (Amst) 2015; 30:21-7. [PMID: 25841100 DOI: 10.1016/j.dnarep.2015.03.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 12/11/2022]
Abstract
Proteins responsible for the integrity of the genome are often used targets in drug therapies against various diseases. The inhibitors of these proteins are also important to study the pathways in genome integrity maintenance. A prominent example is Ugi, a well known cross-species inhibitor protein of the enzyme uracil-DNA glycosylase, responsible for uracil excision from DNA. Here, we report that a Staphylococcus pathogenicity island repressor protein called StlSaPIbov1 (Stl) exhibits potent dUTPase inhibition in Mycobacteria. To our knowledge, this is the first indication of a cross-species inhibitor protein for any dUTPase. We demonstrate that the Staphylococcus aureus Stl and the Mycobacterium tuberculosis dUTPase form a stable complex and that in this complex, the enzymatic activity of dUTPase is strongly inhibited. We also found that the expression of the Stl protein in Mycobacterium smegmatis led to highly increased cellular dUTP levels in the mycobacterial cell, this effect being in agreement with its dUTPase inhibitory role. In addition, Stl expression in M. smegmatis drastically decreased colony forming ability, as well, indicating significant perturbation of the phenotype. Therefore, we propose that Stl can be considered to be a cross-species dUTPase inhibitor and may be used as an important reagent in dUTPase inhibition experiments either in vitro/in situ or in vivo.
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Affiliation(s)
- Rita Hirmondó
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary.
| | - Judit E Szabó
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary
| | - Kinga Nyíri
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary
| | - Szilvia Tarjányi
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary
| | - Paula Dobrotka
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary
| | - Judit Tóth
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta G Vértessy
- Institute of Enzymology, Research Centre for Natural Sciences (RCNS), Hungarian Academy of Sciences, Budapest, Hungary; Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary.
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23
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SHMT1 knockdown induces apoptosis in lung cancer cells by causing uracil misincorporation. Cell Death Dis 2014; 5:e1525. [PMID: 25412303 PMCID: PMC4260740 DOI: 10.1038/cddis.2014.482] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/03/2014] [Accepted: 10/09/2014] [Indexed: 12/15/2022]
Abstract
Reprogramming of cellular metabolism towards de novo serine production fuels the growth of cancer cells, providing essential precursors such as amino acids and nucleotides and controlling the antioxidant and methylation capacities of the cell. The enzyme serine hydroxymethyltransferase (SHMT) has a key role in this metabolic shift, and directs serine carbons to one-carbon units metabolism and thymidilate synthesis. While the mitochondrial isoform of SHMT (SHMT2) has recently been identified as an important player in the control of cell proliferation in several cancer types and as a hot target for anticancer therapies, the role of the cytoplasmic isoform (SHMT1) in cancerogenesis is currently less defined. In this paper we show that SHMT1 is overexpressed in tissue samples from lung cancer patients and lung cancer cell lines, suggesting that, in this widespread type of tumor, SHMT1 plays a relevant role. We show that SHMT1 knockdown in lung cancer cells leads to cell cycle arrest and, more importantly, to p53-dependent apoptosis. Our data demonstrate that the induction of apoptosis does not depend on serine or glycine starvation, but is because of the increased uracil accumulation during DNA replication.
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24
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Ji L, Sasaki T, Sun X, Ma P, Lewis ZA, Schmitz RJ. Methylated DNA is over-represented in whole-genome bisulfite sequencing data. Front Genet 2014; 5:341. [PMID: 25374580 PMCID: PMC4204604 DOI: 10.3389/fgene.2014.00341] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 09/11/2014] [Indexed: 12/31/2022] Open
Abstract
The development of whole-genome bisulfite sequencing (WGBS) has resulted in a number of exciting discoveries about the role of DNA methylation leading to a plethora of novel testable hypotheses. Methods for constructing sodium bisulfite-converted and amplified libraries have recently advanced to the point that the bottleneck for experiments that use WGBS has shifted to data analysis and interpretation. Here we present empirical evidence for an over-representation of reads from methylated DNA in WGBS. This enrichment for methylated DNA is exacerbated by higher cycles of PCR and is influenced by the type of uracil-insensitive DNA polymerase used for amplifying the sequencing library. Future efforts to computationally correct for this enrichment bias will be essential to increasing the accuracy of determining methylation levels for individual cytosines. It is especially critical for studies that seek to accurately quantify DNA methylation levels in populations that may segregate for allelic DNA methylation states.
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Affiliation(s)
- Lexiang Ji
- Department of Genetics, University of Georgia, Athens, GA USA ; Institute of Bioinformatics, University of Georgia, Athens, GA USA
| | - Takahiko Sasaki
- Department of Microbiology, University of Georgia, Athens, GA USA
| | - Xiaoxiao Sun
- Department of Statistics, University of Georgia, Athens, GA USA
| | - Ping Ma
- Department of Statistics, University of Georgia, Athens, GA USA
| | - Zachary A Lewis
- Department of Microbiology, University of Georgia, Athens, GA USA
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25
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Galashevskaya A, Sarno A, Vågbø CB, Aas PA, Hagen L, Slupphaug G, Krokan HE. A robust, sensitive assay for genomic uracil determination by LC/MS/MS reveals lower levels than previously reported. DNA Repair (Amst) 2013; 12:699-706. [PMID: 23742752 DOI: 10.1016/j.dnarep.2013.05.002] [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: 02/18/2013] [Revised: 05/06/2013] [Accepted: 05/09/2013] [Indexed: 10/26/2022]
Abstract
Considerable progress has been made in understanding the origins of genomic uracil and its role in genome stability and host defense; however, the main question concerning the basal level of uracil in DNA remains disputed. Results from assays designed to quantify genomic uracil vary by almost three orders of magnitude. To address the issues leading to this inconsistency, we explored possible shortcomings with existing methods and developed a sensitive LC/MS/MS-based method for the absolute quantification of genomic 2'-deoxyuridine (dUrd). To this end, DNA was enzymatically hydrolyzed to 2'-deoxyribonucleosides and dUrd was purified in a preparative HPLC step and analyzed by LC/MS/MS. The standard curve was linear over four orders of magnitude with a quantification limit of 5 fmol dUrd. Control samples demonstrated high inter-experimental accuracy (94.3%) and precision (CV 9.7%). An alternative method that employed UNG2 to excise uracil from DNA for LC/MS/MS analysis gave similar results, but the intra-assay variability was significantly greater. We quantified genomic dUrd in Ung(+/+) and Ung(-/-) mouse embryonic fibroblasts and human lymphoblastoid cell lines carrying UNG mutations. DNA-dUrd is 5-fold higher in Ung(-/-) than in Ung(+/+) fibroblasts and 11-fold higher in UNG2 dysfunctional than in UNG2 functional lymphoblastoid cells. We report approximately 400-600 dUrd per human or murine genome in repair-proficient cells, which is lower than results using other methods and suggests that genomic uracil levels may have previously been overestimated.
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Affiliation(s)
- Anastasia Galashevskaya
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, NO-7489 Trondheim, Norway
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26
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Gouge J, Ralec C, Henneke G, Delarue M. Molecular recognition of canonical and deaminated bases by P. abyssi family B DNA polymerase. J Mol Biol 2012; 423:315-36. [PMID: 22902479 DOI: 10.1016/j.jmb.2012.07.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 10/28/2022]
Abstract
Euryarchaeal polymerase B can recognize deaminated bases on the template strand, effectively stalling the replication fork 4nt downstream the modified base. Using Pyrococcus abyssi DNA B family polymerase (PabPolB), we investigated the discrimination between deaminated and natural nucleotide(s) by primer extension assays, electrophoretic mobility shift assays, and X-ray crystallography. Structures of complexes between the protein and DNA duplexes with either a dU or a dH in position +4 were solved at 2.3Å and 2.9Å resolution, respectively. The PabPolB is found in the editing mode. A new metal binding site has been uncovered below the base-checking cavity where the +4 base is flipped out; it is fully hydrated in an octahedral fashion and helps guide the strongly kinked template strand. Four other crystal structures with each of the canonical bases were also solved in the editing mode, and the presence of three nucleotides in the exonuclease site caused a shift in the coordination state of its metal A from octahedral to tetrahedral. Surprisingly, we find that all canonical bases also enter the base-checking pocket with very small differences in the binding geometry and in the calculated binding free energy compared to deaminated ones. To explain how this can lead to stalling of the replication fork, the full catalytic pathway and its branches must be taken into account, during which the base is checked several times. Our results strongly suggest a switch from elongation to editing modes right after nucleotide insertion when the modified base is at position +5.
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Affiliation(s)
- Jérôme Gouge
- Unité de Dynamique Structurale des Macromolécules, UMR 3528 du CNRS, Institut Pasteur, 25 rue du Dr Roux, 75015 Paris, France
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27
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Uracil-containing DNA in Drosophila: stability, stage-specific accumulation, and developmental involvement. PLoS Genet 2012; 8:e1002738. [PMID: 22685418 PMCID: PMC3369950 DOI: 10.1371/journal.pgen.1002738] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 04/13/2012] [Indexed: 11/26/2022] Open
Abstract
Base-excision repair and control of nucleotide pools safe-guard against permanent uracil accumulation in DNA relying on two key enzymes: uracil–DNA glycosylase and dUTPase. Lack of the major uracil–DNA glycosylase UNG gene from the fruit fly genome and dUTPase from fruit fly larvae prompted the hypotheses that i) uracil may accumulate in Drosophila genomic DNA where it may be well tolerated, and ii) this accumulation may affect development. Here we show that i) Drosophila melanogaster tolerates high levels of uracil in DNA; ii) such DNA is correctly interpreted in cell culture and embryo; and iii) under physiological spatio-temporal control, DNA from fruit fly larvae, pupae, and imago contain greatly elevated levels of uracil (200–2,000 uracil/million bases, quantified using a novel real-time PCR–based assay). Uracil is accumulated in genomic DNA of larval tissues during larval development, whereas DNA from imaginal tissues contains much less uracil. Upon pupation and metamorphosis, uracil content in DNA is significantly decreased. We propose that the observed developmental pattern of uracil–DNA is due to the lack of the key repair enzyme UNG from the Drosophila genome together with down-regulation of dUTPase in larval tissues. In agreement, we show that dUTPase silencing increases the uracil content in DNA of imaginal tissues and induces strong lethality at the early pupal stages, indicating that tolerance of highly uracil-substituted DNA is also stage-specific. Silencing of dUTPase perturbs the physiological pattern of uracil–DNA accumulation in Drosophila and leads to a strongly lethal phenotype in early pupal stages. These findings suggest a novel role of uracil-containing DNA in Drosophila development and metamorphosis and present a novel example for developmental effects of dUTPase silencing in multicellular eukaryotes. Importantly, we also show lack of the UNG gene in all available genomes of other Holometabola insects, indicating a potentially general tolerance and developmental role of uracil–DNA in this evolutionary clade. The usual paradigm confines “normal” DNA of living cells to a well-defined restricted chemical space populated with only four bases (adenine, thymine, guanine, and cytosine) and some of their methylated derivatives (e.g. 5′-methyl-cytosine). Uracil is not considered to be a “normal” DNA base, except in several bacteriophages. On the contrary, uracil is generally considered to be an error in DNA. We show that Drosophila cells interpret uracil-substituted DNA as normal DNA, due to lack of two repair enzymes. Importantly, this unusual trait is under developmental control and applies only for animals before pupation. Metamorphosis is drastically perturbed by silencing of dUTPase, responsible for keeping uracil out of DNA. Our results argue that in Drosophila, and perhaps in other Holometabola insects as well, uracil–DNA plays a dedicated physiological role.
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28
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Pecsi I, Hirmondo R, Brown AC, Lopata A, Parish T, Vertessy BG, Tóth J. The dUTPase enzyme is essential in Mycobacterium smegmatis. PLoS One 2012; 7:e37461. [PMID: 22655049 PMCID: PMC3360063 DOI: 10.1371/journal.pone.0037461] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 04/20/2012] [Indexed: 02/06/2023] Open
Abstract
Thymidine biosynthesis is essential in all cells. Inhibitors of the enzymes involved in this pathway (e.g. methotrexate) are thus frequently used as cytostatics. Due to its pivotal role in mycobacterial thymidylate synthesis dUTPase, which hydrolyzes dUTP into the dTTP precursor dUMP, has been suggested as a target for new antitubercular agents. All mycobacterial genomes encode dUTPase with a mycobacteria-specific surface loop absent in the human dUTPase. Using Mycobacterium smegmatis as a fast growing model for Mycobacterium tuberculosis, we demonstrate that dUTPase knock-out results in lethality that can be reverted by complementation with wild-type dUTPase. Interestingly, a mutant dUTPase gene lacking the genus-specific loop was unable to complement the knock-out phenotype. We also show that deletion of the mycobacteria-specific loop has no major effect on dUTPase enzymatic properties in vitro and thus a yet to be identified loop-specific function seems to be essential within the bacterial cell context. In addition, here we demonstrated that Mycobacterium tuberculosis dUTPase is fully functional in Mycobacterium smegmatis as it rescues the lethal knock-out phenotype. Our results indicate the potential of dUTPase as a target for antitubercular drugs and identify a genus-specific surface loop on the enzyme as a selective target.
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Affiliation(s)
- Ildiko Pecsi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom
| | - Rita Hirmondo
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Amanda C. Brown
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom
| | - Anna Lopata
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tanya Parish
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom
| | - Beata G. Vertessy
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
- Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest, Hungary
- * E-mail: (BGV); (JT)
| | - Judit Tóth
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail: (BGV); (JT)
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29
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Yang J, Osman K, Iqbal M, Stekel DJ, Luo Z, Armstrong SJ, Franklin FCH. Inferring the Brassica rapa Interactome Using Protein-Protein Interaction Data from Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2012; 3:297. [PMID: 23293649 PMCID: PMC3537189 DOI: 10.3389/fpls.2012.00297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 12/11/2012] [Indexed: 05/06/2023]
Abstract
Following successful completion of the Brassica rapa sequencing project, the next step is to investigate functions of individual genes/proteins. For Arabidopsis thaliana, large amounts of protein-protein interaction (PPI) data are available from the major PPI databases (DBs). It is known that Brassica crop species are closely related to A. thaliana. This provides an opportunity to infer the B. rapa interactome using PPI data available from A. thaliana. In this paper, we present an inferred B. rapa interactome that is based on the A. thaliana PPI data from two resources: (i) A. thaliana PPI data from three major DBs, BioGRID, IntAct, and TAIR. (ii) ortholog-based A. thaliana PPI predictions. Linking between B. rapa and A. thaliana was accomplished in three complementary ways: (i) ortholog predictions, (ii) identification of gene duplication based on synteny and collinearity, and (iii) BLAST sequence similarity search. A complementary approach was also applied, which used known/predicted domain-domain interaction data. Specifically, since the two species are closely related, we used PPI data from A. thaliana to predict interacting domains that might be conserved between the two species. The predicted interactome was investigated for the component that contains known A. thaliana meiotic proteins to demonstrate its usability.
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Affiliation(s)
- Jianhua Yang
- University of BirminghamBirmingham, UK
- *Correspondence: Jianhua Yang and F. Chris H. Franklin, University of Birmingham, B152TT Birmingham, UK. e-mail: ,
| | - Kim Osman
- University of BirminghamBirmingham, UK
| | | | | | - Zewei Luo
- University of BirminghamBirmingham, UK
| | | | - F. Chris H. Franklin
- University of BirminghamBirmingham, UK
- *Correspondence: Jianhua Yang and F. Chris H. Franklin, University of Birmingham, B152TT Birmingham, UK. e-mail: ,
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30
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Bozóky Z, Róna G, Klement É, Medzihradszky KF, Merényi G, Vértessy BG, Friedrich P. Calpain-catalyzed proteolysis of human dUTPase specifically removes the nuclear localization signal peptide. PLoS One 2011; 6:e19546. [PMID: 21625588 PMCID: PMC3098232 DOI: 10.1371/journal.pone.0019546] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Accepted: 04/01/2011] [Indexed: 11/19/2022] Open
Abstract
Background Calpain proteases drive intracellular signal transduction via specific proteolysis of multiple substrates upon Ca2+-induced activation. Recently, dUTPase, an enzyme essential to maintain genomic integrity, was identified as a physiological calpain substrate in Drosophila cells. Here we investigate the potential structural/functional significance of calpain-activated proteolysis of human dUTPase. Methodology/Principal Findings Limited proteolysis of human dUTPase by mammalian m-calpain was investigated in the presence and absence of cognate ligands of either calpain or dUTPase. Significant proteolysis was observed only in the presence of Ca(II) ions, inducing calpain action. The presence or absence of the dUTP-analogue α,β-imido-dUTP did not show any effect on Ca2+-calpain-induced cleavage of human dUTPase. The catalytic rate constant of dUTPase was unaffected by calpain cleavage. Gel electrophoretic analysis showed that Ca2+-calpain-induced cleavage of human dUTPase resulted in several distinctly observable dUTPase fragments. Mass spectrometric identification of the calpain-cleaved fragments identified three calpain cleavage sites (between residues 4SE5; 7TP8; and 31LS32). The cleavage between the 31LS32 peptide bond specifically removes the flexible N-terminal nuclear localization signal, indispensable for cognate localization. Conclusions/Significance Results argue for a mechanism where Ca2+-calpain may regulate nuclear availability and degradation of dUTPase.
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Affiliation(s)
- Zoltán Bozóky
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gergely Róna
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Éva Klement
- Proteomics Research Group, Biological Research Centre (BRC), Hungarian Academy of Sciences, Szeged, Hungary
| | - Katalin F. Medzihradszky
- Proteomics Research Group, Biological Research Centre (BRC), Hungarian Academy of Sciences, Szeged, Hungary
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Gábor Merényi
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta G. Vértessy
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
- Department of Applied Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
- * E-mail: (BGV); (PF)
| | - Peter Friedrich
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail: (BGV); (PF)
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31
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HIV DNA is heavily uracilated, which protects it from autointegration. Proc Natl Acad Sci U S A 2011; 108:9244-9. [PMID: 21576478 DOI: 10.1073/pnas.1102943108] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human immune cells infected by HIV naturally contain high uracil content, and HIV reverse transcriptase (RT) does not distinguish between dUTP and dTTP. Many DNA viruses and retroviruses encode a dUTPase or uracil-DNA glycosylase (UNG) to counteract uracil incorporation. However, although HIV virions are thought to contain cellular UNG2, replication of HIV produced in cells lacking UNG activity does not appear to be impaired. Here we show that HIV reverse transcripts generated in primary human immune cells are heavily uracilated (>500 uracils per 10 kb HIV genome). We find that HIV DNA uracilation, rather than being dangerous, may promote the early phase of the viral life cycle. Shortly after reverse transcription, the ends of the HIV DNA are activated by the viral integrase (IN) in preparation for chromosomal insertion. However, the activated ends can attack the viral DNA itself in a suicidal side pathway, called autointegration. We find here that uracilation of target DNA inhibits the strand transfer of HIV DNA ends by IN, thereby inhibiting autointegration and facilitating chromosomal integration and viral replication. When uracilation is increased by incubating uracil-poor cells in the presence of increasing concentrations of dUTP or by infecting with virus that contains the cytosine deaminase APOBEC3G (A3G), the proportion of reverse transcripts that undergo suicidal autointegration decreases. Thus, HIV tolerates, or even benefits from, nonmutagenic uracil incorporation during reverse transcription in human immune cells.
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