1
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Moreira FA, Escobar JFB, Giordani C, Caseli L. Langmuir monolayers provide an effective strategy for studying molecular recognition of nucleobases using alkylated nucleotides. Colloids Surf B Biointerfaces 2024; 244:114129. [PMID: 39121572 DOI: 10.1016/j.colsurfb.2024.114129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 07/18/2024] [Accepted: 07/27/2024] [Indexed: 08/12/2024]
Abstract
Molecular Recognition in nucleotides is crucial for medicine, underpinning precise interactions in genetic replication and therapy. Alkylated nucleotides, in particular, play a key role in modifying DNA to inhibit cancer cell growth. In this study, we focused on an alkylated nucleotide, PNM2 (3',4',6'-O-tristearoyl uridine or uridine tri-stearate), to investigate the interaction between adenine molecules in the aqueous subphase and PNM2 Langmuir monolayers. Utilizing techniques such as tensiometry, Brewster angle microscopy, infrared spectroscopy, surface potential measurements, and dilatational surface rheology, we found compelling evidence of molecular Recognition between the polar head of the insoluble amphiphile (uridine) in the monolayer and adenine in the aqueous subphase, attributed to hydrogen bonding. These interactions significantly influenced the physicochemical properties of the air-water interface, including monolayer expansion upon molecular recognition, decreased dilatational modulus, increased tensiometric stability of the monolayer when compressed to relevant surface pressures, and decreased surface potential. These findings are noteworthy for drug development, providing crucial insights into the mechanisms of nucleotide interactions.
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Affiliation(s)
- Felipe Almeida Moreira
- Department of Chemistry, Federal University of Sao Paulo, Rua São Nicolau, 210, Diadema, SP 09913-030, Brazil
| | - Jhon Fernando Berrio Escobar
- Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 No. 52-21, Medellìn 050010, Colombia
| | - Cristiano Giordani
- Instituto de Física, Universidad de Antioquia, Calle 70 No. 52-21, Medellìn 050010, Colombia; Grupo Productos Naturales Marinos, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia, Calle 70 No. 52-21, Medellín 050010, Colombia.
| | - Luciano Caseli
- Department of Chemistry, Federal University of Sao Paulo, Rua São Nicolau, 210, Diadema, SP 09913-030, Brazil.
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2
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Nicholson MD, Anderson CJ, Odom DT, Aitken SJ, Taylor MS. DNA lesion bypass and the stochastic dynamics of transcription-coupled repair. Proc Natl Acad Sci U S A 2024; 121:e2403871121. [PMID: 38717857 PMCID: PMC11098089 DOI: 10.1073/pnas.2403871121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 04/09/2024] [Indexed: 05/18/2024] Open
Abstract
DNA base damage is a major source of oncogenic mutations and disruption to gene expression. The stalling of RNA polymerase II (RNAP) at sites of DNA damage and the subsequent triggering of repair processes have major roles in shaping the genome-wide distribution of mutations, clearing barriers to transcription, and minimizing the production of miscoded gene products. Despite its importance for genetic integrity, key mechanistic features of this transcription-coupled repair (TCR) process are controversial or unknown. Here, we exploited a well-powered in vivo mammalian model system to explore the mechanistic properties and parameters of TCR for alkylation damage at fine spatial resolution and with discrimination of the damaged DNA strand. For rigorous interpretation, a generalizable mathematical model of DNA damage and TCR was developed. Fitting experimental data to the model and simulation revealed that RNA polymerases frequently bypass lesions without triggering repair, indicating that small alkylation adducts are unlikely to be an efficient barrier to gene expression. Following a burst of damage, the efficiency of transcription-coupled repair gradually decays through gene bodies with implications for the occurrence and accurate inference of driver mutations in cancer. The reinitation of transcription from the repair site is not a general feature of transcription-coupled repair, and the observed data is consistent with reinitiation never taking place. Collectively, these results reveal how the directional but stochastic activity of TCR shapes the distribution of mutations following DNA damage.
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Affiliation(s)
- Michael D. Nicholson
- Cancer Research United Kingdom Scotland Centre, Institute of Genetics and Cancer, University of Edinburgh, EdinburghEH4 2XU, United Kingdom
| | - Craig J. Anderson
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, EdinburghEH4 2XU, United Kingdom
| | - Duncan T. Odom
- Division of Regulatory Genomics and Cancer Evolution (B270), German Cancer Research Center, Heidelberg69120, Germany
- Cancer Research United Kingdom Cambridge Institute, University of Cambridge, CambridgeCB2 0RE, United Kingdom
| | - Sarah J. Aitken
- Cancer Research United Kingdom Cambridge Institute, University of Cambridge, CambridgeCB2 0RE, United Kingdom
- Medical Research Council Toxicology Unit, University of Cambridge, CambridgeCB2 1QR, United Kingdom
- Department of Histopathology, Cambridge University Hospitals National Health Service Foundation Trust, CambridgeCB2 0QQ, United Kingdom
| | - Martin S. Taylor
- Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, EdinburghEH4 2XU, United Kingdom
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3
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Gao S, Hou P, Oh J, Wang D, Greenberg MM. Molecular Mechanism of RNA Polymerase II Transcriptional Mutagenesis by the Epimerizable DNA Lesion, Fapy·dG. J Am Chem Soc 2024; 146:6274-6282. [PMID: 38393762 PMCID: PMC10932878 DOI: 10.1021/jacs.3c14476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Oxidative DNA lesions cause significant detrimental effects on a living species. Two major DNA lesions resulting from dG oxidation, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo) and formamidopyrimidine (Fapy·dG), are produced from a common chemical intermediate. Fapy·dG is formed in comparable yields under oxygen-deficient conditions. Replicative bypass of Fapy·dG in human cells is more mutagenic than that of 8-OxodGuo. Despite the biological importance of transcriptional mutagenesis, there are no reports of the effects of Fapy·dG on RNA polymerase II (Pol II) activity. Here we perform comprehensive kinetic studies to investigate the impact of Fapy·dG on three key transcriptional fidelity checkpoint steps by Pol II: insertion, extension, and proofreading steps. The ratios of error-free versus error-prone incorporation opposite Fapy·dG are significantly reduced in comparison with undamaged dG. Similarly, Fapy·dG:A mispair is extended with comparable efficiency as that of the error-free, Fapy·dG:C base pair. The α- and β-configurational isomers of Fapy·dG have distinct effects on Pol II insertion and extension. Pol II can preferentially cleave error-prone products by proofreading. To further understand the structural basis of transcription processing of Fapy·dG, five different structures were solved, including Fapy·dG template-loading state (apo), error-free cytidine triphosphate (CTP) binding state (prechemistry), error-prone ATP binding state (prechemistry), error-free Fapy·dG:C product state (postchemistry), and error-prone Fapy·dG:A product state (postchemistry), revealing distinctive nucleotide binding and product states. Taken together, our study provides a comprehensive mechanistic framework for better understanding how Fapy·dG lesions impact transcription and subsequent pathological consequences.
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Affiliation(s)
- Shijun Gao
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Peini Hou
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Regulatory Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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4
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Samir S. Human DNA Mutations and their Impact on Genetic Disorders. Recent Pat Biotechnol 2024; 18:288-315. [PMID: 37936448 DOI: 10.2174/0118722083255081231020055309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 07/25/2023] [Accepted: 09/18/2023] [Indexed: 11/09/2023]
Abstract
DNA is a remarkably precise medium for copying and storing biological information. It serves as a design for cellular machinery that permits cells, organs, and even whole organisms to work. The fidelity of DNA replication results from the action of hundreds of genes involved in proofreading and damage repair. All human cells can acquire genetic changes in their DNA all over life. Genetic mutations are changes to the DNA sequence that happen during cell division when the cells make copies of themselves. Mutations in the DNA can cause genetic illnesses such as cancer, or they could help humans better adapt to their environment over time. The endogenous reactive metabolites, therapeutic medicines, and an excess of environmental mutagens, such as UV rays all continuously damage DNA, compromising its integrity. One or more chromosomal alterations and point mutations at a single site (monogenic mutation) including deletions, duplications, and inversions illustrate such DNA mutations. Genetic conditions can occur when an altered gene is inherited from parents, which increases the risk of developing that particular condition, or some gene alterations can happen randomly. Moreover, symptoms of genetic conditions depend on which gene has a mutation. There are many different diseases and conditions caused by mutations. Some of the most common genetic conditions are Alzheimer's disease, some cancers, cystic fibrosis, Down syndrome, and sickle cell disease. Interestingly, scientists find that DNA mutations are more common than formerly thought. This review outlines the main DNA mutations that occur along the human genome and their influence on human health. The subject of patents pertaining to DNA mutations and genetic disorders has been brought up.
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Affiliation(s)
- Safia Samir
- Department of Biochemistry and Molecular Biology, Theodor Bilharz Research Institute, Giza, Egypt
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5
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Oh J, Shan Z, Hoshika S, Xu J, Chong J, Benner SA, Lyumkis D, Wang D. A unified Watson-Crick geometry drives transcription of six-letter expanded DNA alphabets by E. coli RNA polymerase. Nat Commun 2023; 14:8219. [PMID: 38086811 PMCID: PMC10716388 DOI: 10.1038/s41467-023-43735-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
Artificially Expanded Genetic Information Systems (AEGIS) add independently replicable unnatural nucleotide pairs to the natural G:C and A:T/U pairs found in native DNA, joining the unnatural pairs through alternative modes of hydrogen bonding. Whether and how AEGIS pairs are recognized and processed by multi-subunit cellular RNA polymerases (RNAPs) remains unknown. Here, we show that E. coli RNAP selectively recognizes unnatural nucleobases in a six-letter expanded genetic system. High-resolution cryo-EM structures of three RNAP elongation complexes containing template-substrate UBPs reveal the shared principles behind the recognition of AEGIS and natural base pairs. In these structures, RNAPs are captured in an active state, poised to perform the chemistry step. At this point, the unnatural base pair adopts a Watson-Crick geometry, and the trigger loop is folded into an active conformation, indicating that the mechanistic principles underlying recognition and incorporation of natural base pairs also apply to AEGIS unnatural base pairs. These data validate the design philosophy of AEGIS unnatural basepairs. Further, we provide structural evidence supporting a long-standing hypothesis that pair mismatch during transcription occurs via tautomerization. Together, our work highlights the importance of Watson-Crick complementarity underlying the design principles of AEGIS base pair recognition.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Pharmacy, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Zelin Shan
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Shuichi Hoshika
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA.
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute 10550 N Torrey Pines Road, La Jolla, CA, 92037, USA.
- Graduate School of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093, USA.
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6
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Gohil D, Sarker AH, Roy R. Base Excision Repair: Mechanisms and Impact in Biology, Disease, and Medicine. Int J Mol Sci 2023; 24:14186. [PMID: 37762489 PMCID: PMC10531636 DOI: 10.3390/ijms241814186] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Base excision repair (BER) corrects forms of oxidative, deamination, alkylation, and abasic single-base damage that appear to have minimal effects on the helix. Since its discovery in 1974, the field has grown in several facets: mechanisms, biology and physiology, understanding deficiencies and human disease, and using BER genes as potential inhibitory targets to develop therapeutics. Within its segregation of short nucleotide (SN-) and long patch (LP-), there are currently six known global mechanisms, with emerging work in transcription- and replication-associated BER. Knockouts (KOs) of BER genes in mouse models showed that single glycosylase knockout had minimal phenotypic impact, but the effects were clearly seen in double knockouts. However, KOs of downstream enzymes showed critical impact on the health and survival of mice. BER gene deficiency contributes to cancer, inflammation, aging, and neurodegenerative disorders. Medicinal targets are being developed for single or combinatorial therapies, but only PARP and APE1 have yet to reach the clinical stage.
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Affiliation(s)
- Dhara Gohil
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA;
| | - Altaf H. Sarker
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA;
| | - Rabindra Roy
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA;
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7
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Zhu W, Wang H, Li X, Tie W, Huo B, Zhu A, Li L. Amplification, Enrichment, and Sequencing of Mutagenic Methylated DNA Adduct through Specifically Pairing with Unnatural Nucleobases. J Am Chem Soc 2022; 144:20165-20170. [DOI: 10.1021/jacs.2c06110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wuyuan Zhu
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
- State Key Laboratory of Cell Differentiation Regulation and Target Drug, Henan Normal University, Xinxiang 453007, China
| | - Honglei Wang
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xiaohuan Li
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Wenchao Tie
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Bianbian Huo
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Anlian Zhu
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Lingjun Li
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
- State Key Laboratory of Cell Differentiation Regulation and Target Drug, Henan Normal University, Xinxiang 453007, China
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8
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Jaijyan DK, Govindasamy K, Lee M, Zhu H. A chemical method for generating live-attenuated, replication-defective DNA viruses for vaccine development. CELL REPORTS METHODS 2022; 2:100287. [PMID: 36160049 PMCID: PMC9499982 DOI: 10.1016/j.crmeth.2022.100287] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/22/2022] [Accepted: 08/17/2022] [Indexed: 11/22/2022]
Abstract
The development of a chemically attenuated, replication-incompetent virus vaccine can provide protection against diseases caused by DNA viruses. In this study, we have developed a method to produce live-attenuated, replication-defective viruses using centanamycin (CM), a chemical compound that alkylates the A-T-rich minor groove of the DNA and thereby blocks DNA replication. We tested the efficacy of CM to produce live-attenuated, replication-defective human cytomegalovirus, mouse cytomegalovirus, and herpes simplex virus-2 (HSV-2), suggesting a broad application for generating live-attenuated, replication-defective DNA viruses. Mass spectrometry analysis showed that CM alkylate viral DNA at the adenine-N3 position. Moreover, mice immunization with CM-attenuated mouse cytomegalovirus (MCMV) produced a robust immune response and reduced the viral load in immunized animals against challenges with live, wild-type MCMV. Our study offers a unifying and attractive therapeutic opportunity that chemically attenuated live DNA viruses can be readily developed as new frontline vaccines.
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Affiliation(s)
- Dabbu Kumar Jaijyan
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers – New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
| | - Kavitha Govindasamy
- New Jersey Center for Science, Technology and Mathematics, Kean University, Union, NJ, USA
| | - Moses Lee
- Department of Chemistry, Georgia State University, Atlanta, GA, USA
| | - Hua Zhu
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers – New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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9
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Cui R, Li H, Zhao J, Li X, Gan J, Ma J. Structural insights into the dual activities of the two-barrel RNA polymerase QDE-1. Nucleic Acids Res 2022; 50:10169-10186. [PMID: 36039765 PMCID: PMC9508822 DOI: 10.1093/nar/gkac727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/01/2022] [Accepted: 08/27/2022] [Indexed: 11/19/2022] Open
Abstract
Neurospora crassa protein QDE-1, a member of the two-barrel polymerase superfamily, possesses both DNA- and RNA-dependent RNA polymerase (DdRP and RdRP) activities. The dual activities are essential for the production of double-stranded RNAs (dsRNAs), the precursors of small interfering RNAs (siRNAs) in N. crassa. Here, we report five complex structures of N-terminal truncated QDE-1 (QDE-1ΔN), representing four different reaction states: DNA/RNA-templated elongation, the de novo initiation of RNA synthesis, the first step of nucleotide condensation during de novo initiation and initial NTP loading. The template strand is aligned by a bridge-helix and double-psi beta-barrels 2 (DPBB2), the RNA product is held by DPBB1 and the slab domain. The DNA template unpairs with the RNA product at position –7, but the RNA template remains paired. The NTP analog coordinates with cations and is precisely positioned at the addition site by a rigid trigger loop and a proline-containing loop in the active center. The unique C-terminal tail from the QDE-1 dimer partner inserts into the substrate-binding cleft and plays regulatory roles in RNA synthesis. Collectively, this work elucidates the conserved mechanisms for DNA/RNA-dependent dual activities by QDE-1 and other two-barrel polymerase superfamily members.
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Affiliation(s)
- Ruixue Cui
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Hao Li
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jin Zhao
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xuhang Li
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jianhua Gan
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jinbiao Ma
- Huashan Hospital affiliated to Fudan University, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute of Complex Systems, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
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10
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Li X, Cao G, Liu X, Tang TS, Guo C, Liu H. Polymerases and DNA Repair in Neurons: Implications in Neuronal Survival and Neurodegenerative Diseases. Front Cell Neurosci 2022; 16:852002. [PMID: 35846567 PMCID: PMC9279898 DOI: 10.3389/fncel.2022.852002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/23/2022] [Indexed: 12/22/2022] Open
Abstract
Most of the neurodegenerative diseases and aging are associated with reactive oxygen species (ROS) or other intracellular damaging agents that challenge the genome integrity of the neurons. As most of the mature neurons stay in G0/G1 phase, replication-uncoupled DNA repair pathways including BER, NER, SSBR, and NHEJ, are pivotal, efficient, and economic mechanisms to maintain genomic stability without reactivating cell cycle. In these progresses, polymerases are prominent, not only because they are responsible for both sensing and repairing damages, but also for their more diversified roles depending on the cell cycle phase and damage types. In this review, we summarized recent knowledge on the structural and biochemical properties of distinct polymerases, including DNA and RNA polymerases, which are known to be expressed and active in nervous system; the biological relevance of these polymerases and their interactors with neuronal degeneration would be most graphically illustrated by the neurological abnormalities observed in patients with hereditary diseases associated with defects in DNA repair; furthermore, the vicious cycle of the trinucleotide repeat (TNR) and impaired DNA repair pathway is also discussed. Unraveling the mechanisms and contextual basis of the role of the polymerases in DNA damage response and repair will promote our understanding about how long-lived postmitotic cells cope with DNA lesions, and why disrupted DNA repair contributes to disease origin, despite the diversity of mutations in genes. This knowledge may lead to new insight into the development of targeted intervention for neurodegenerative diseases.
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Affiliation(s)
- Xiaoling Li
- Nano-Biotechnology Key Lab of Hebei Province, Yanshan University, Qinhuangdao, China
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
- Xiaoling Li
| | - Guanghui Cao
- Nano-Biotechnology Key Lab of Hebei Province, Yanshan University, Qinhuangdao, China
| | - Xiaokang Liu
- Nano-Biotechnology Key Lab of Hebei Province, Yanshan University, Qinhuangdao, China
| | - Tie-Shan Tang
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
| | - Caixia Guo
- Beijing Institute of Genomics, University of Chinese Academy of Sciences, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, China
- *Correspondence: Caixia Guo
| | - Hongmei Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Hongmei Liu
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11
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Zhao CL, Qiao X, Liu XM, Song XQ, Zou YH, Li DQ, Yu XW, Bao WG, Xu JY. Rapid DNA interstrand cross-linking of Pt(IV) compound. Eur J Pharmacol 2022; 925:174985. [PMID: 35489419 DOI: 10.1016/j.ejphar.2022.174985] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/23/2022] [Accepted: 04/25/2022] [Indexed: 11/30/2022]
Abstract
Pt(IV) anticancer compounds have been developed for several decades to overcome the drawbacks of their Pt(II) congeners, and the reduction of Pt(IV) to Pt(II) has been commonly regarded as a necessary step in the activation of Pt(IV) compounds prior to targeting DNA. However, blockage of glutathione (GSH) biosynthesis resulted in a slight effect on the cytotoxicity of oxoplatin in yeast Saccharomyces cerevisiae strains, urging us to reconsider the mechanism of actions for the "inert" Pt(IV) complexes. Using X-ray absorption near-edge spectroscopy (XANES), our data demonstrated that Pt(IV) complex oxoplatin could bind to DNA in a tetravalent state. Both alkaline denaturing agarose electrophoresis and thermal denaturation-renaturation assay revealed that oxoplatin could rapidly produce stable interstrand crosslinks (ICLs), which can further translate into a fast cell-killing process in cancer cells. Using quantitative real-time PCR and immunofluorescence analysis, we also proved that Pt(IV) complex oxoplatin could induce a quick intracellular response of the FA/BRCA pathway in cancer cells that involves the DNA interstrand crosslinking repair system, and this quick response to ICLs was independent with the intracellular GSH levels. Cell cycle analysis showed that short incubation with oxoplatin can induce a strong S phase arrest in HeLa cells, indicating that the rapid interstrand crosslinks produced by oxoplatin might stall the replication fork, result in the double-strand breaks, and eventually induce cell death. Our results implied that, besides the reduction mechanism to release the Pt(II) congeners, direct and rapid interstrand cross-linking with DNA by Pt(IV) compounds might be a unique mechanism for Pt(IV) compounds, which may provide new insight for the development of next-generation platinum-based drugs.
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Affiliation(s)
- Chun-Lai Zhao
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Xin Qiao
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Xiao-Meng Liu
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Xue-Qing Song
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Yun-Hong Zou
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Dan-Qing Li
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Xia-Wen Yu
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China
| | - Wei-Guo Bao
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China.
| | - Jing-Yuan Xu
- Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, China.
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12
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Li Y, Hecht SS. Metabolic Activation and DNA Interactions of Carcinogenic N-Nitrosamines to Which Humans Are Commonly Exposed. Int J Mol Sci 2022; 23:ijms23094559. [PMID: 35562949 PMCID: PMC9105260 DOI: 10.3390/ijms23094559] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 02/04/2023] Open
Abstract
Carcinogenic N-nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These carcinogens-widely detectable in relatively low levels in food, water, cosmetics, and drugs-are well-established and powerful animal carcinogens. The electrophiles resulting from the cytochrome P450-mediated metabolism of N-nitrosamines can readily react with DNA and form covalent addition products (DNA adducts) that play a central role in carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and DNA interactions of 10 carcinogenic N-nitrosamines to which humans are commonly exposed. Certain DNA adducts such as O6-methylguanine with established miscoding properties play central roles in the cancer induction process, whereas others have been linked to the high incidence of certain types of cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and DNA interactions of these 10 carcinogenic N-nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: ; Tel.: +1-612-624-8187
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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13
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Zhang Y, Han L, Tian X, Peng C, Chen Y. Ligand‐Directed Caging Enables the Control of Endogenous DNA Alkyltransferase Activity with Light inside Live Cells. Angew Chem Int Ed Engl 2022; 61:e202115472. [DOI: 10.1002/anie.202115472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Indexed: 12/29/2022]
Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Lili Han
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
| | - Xiaoxu Tian
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Chao Peng
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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14
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Zhang Y, Han L, Tian X, Peng C, Chen Y. Ligand‐Directed Caging Enables the Control of Endogenous DNA Alkyltransferase Activity with Light inside Live Cells. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Lili Han
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
| | - Xiaoxu Tian
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Chao Peng
- National Facility for Protein Science in Shanghai Zhangjiang Lab Shanghai Advanced Research Institute Chinese Academy of Science Shanghai 201210 China
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry Centre of Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
- School of Physical Science and Technology ShanghaiTech University 100 Haike Road Shanghai 201210 China
- School of Chemistry and Material Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences 1 Sub-lane Xiangshan Hangzhou 310024 China
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15
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Oh J, Jia T, Xu J, Chong J, Dervan PB, Wang D. RNA polymerase II trapped on a molecular treadmill: Structural basis of persistent transcriptional arrest by a minor groove DNA binder. Proc Natl Acad Sci U S A 2022; 119:e2114065119. [PMID: 35022237 PMCID: PMC8784135 DOI: 10.1073/pnas.2114065119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023] Open
Abstract
Elongating RNA polymerase II (Pol II) can be paused or arrested by a variety of obstacles. These obstacles include DNA lesions, DNA-binding proteins, and small molecules. Hairpin pyrrole-imidazole (Py-Im) polyamides bind to the minor groove of DNA in a sequence-specific manner and induce strong transcriptional arrest. Remarkably, this Py-Im-induced Pol II transcriptional arrest is persistent and cannot be rescued by transcription factor TFIIS. In contrast, TFIIS can effectively rescue the transcriptional arrest induced by a nucleosome barrier. The structural basis of Py-Im-induced transcriptional arrest and why TFIIS cannot rescue this arrest remain elusive. Here we determined the X-ray crystal structures of four distinct Pol II elongation complexes (Pol II ECs) in complex with hairpin Py-Im polyamides as well as of the hairpin Py-Im polyamides-dsDNA complex. We observed that the Py-Im oligomer directly interacts with RNA Pol II residues, introduces compression of the downstream DNA duplex, prevents Pol II forward translocation, and induces Pol II backtracking. These results, together with biochemical studies, provide structural insight into the molecular mechanism by which Py-Im blocks transcription. Our structural study reveals why TFIIS fails to promote Pol II bypass of Py-Im-induced transcriptional arrest.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Tiezheng Jia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Peter B Dervan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125;
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
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16
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Agapov A, Olina A, Kulbachinskiy A. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3018-3041. [PMID: 35323981 PMCID: PMC8989532 DOI: 10.1093/nar/gkac174] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 11/14/2022] Open
Abstract
Cellular DNA is continuously transcribed into RNA by multisubunit RNA polymerases (RNAPs). The continuity of transcription can be disrupted by DNA lesions that arise from the activities of cellular enzymes, reactions with endogenous and exogenous chemicals or irradiation. Here, we review available data on translesion RNA synthesis by multisubunit RNAPs from various domains of life, define common principles and variations in DNA damage sensing by RNAP, and consider existing controversies in the field of translesion transcription. Depending on the type of DNA lesion, it may be correctly bypassed by RNAP, or lead to transcriptional mutagenesis, or result in transcription stalling. Various lesions can affect the loading of the templating base into the active site of RNAP, or interfere with nucleotide binding and incorporation into RNA, or impair RNAP translocation. Stalled RNAP acts as a sensor of DNA damage during transcription-coupled repair. The outcome of DNA lesion recognition by RNAP depends on the interplay between multiple transcription and repair factors, which can stimulate RNAP bypass or increase RNAP stalling, and plays the central role in maintaining the DNA integrity. Unveiling the mechanisms of translesion transcription in various systems is thus instrumental for understanding molecular pathways underlying gene regulation and genome stability.
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Affiliation(s)
- Aleksei Agapov
- Correspondence may also be addressed to Aleksei Agapov. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
| | - Anna Olina
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute” Moscow 123182, Russia
| | - Andrey Kulbachinskiy
- To whom correspondence should be addressed. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
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17
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Yan W, Deng XW, Yang C, Tang X. The Genome-Wide EMS Mutagenesis Bias Correlates With Sequence Context and Chromatin Structure in Rice. FRONTIERS IN PLANT SCIENCE 2021; 12:579675. [PMID: 33841451 PMCID: PMC8025102 DOI: 10.3389/fpls.2021.579675] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Ethyl methanesulfonate (EMS) is a chemical mutagen believed to mainly induce G/C to A/T transitions randomly in plant genomes. However, mutant screening for phenotypes often gets multiple alleles for one gene but no mutant for other genes. We investigated the potential EMS mutagenesis bias and the possible correlations with sequence context and chromatin structure using the whole genome resequencing data collected from 52 rice EMS mutants. We defined the EMS-induced single nucleotide polymorphic sites (SNPs) and explored the genomic factors associated with EMS mutagenesis bias. Compared with natural SNPs presented in the Rice3K project, EMS showed a preference on G/C sites with flanking sequences also higher in GC contents. The composition of local dinucleotides and trinucleotides was also associated with the efficiency of EMS mutagenesis. The biased distribution of EMS-induced SNPs was positively correlated with CpG numbers, transposable element contents, and repressive epigenetic markers but negatively with gene expression, the euchromatin marker DNase I hypersensitive sites, and active epigenetic markers, suggesting that sequence context and chromatin structure might correlate with the efficiency of EMS mutagenesis. Exploring the genome-wide features of EMS mutagenesis and correlations with epigenetic modifications will help in the understanding of DNA repair mechanism.
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Affiliation(s)
- Wei Yan
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- Shenzhen Institute of Molecular Crop Design, Shenzhen, China
| | - Xing Wang Deng
- Shenzhen Institute of Molecular Crop Design, Shenzhen, China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Chengwei Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiaoyan Tang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- Shenzhen Institute of Molecular Crop Design, Shenzhen, China
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18
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Tsao N, Schärer OD, Mosammaparast N. The complexity and regulation of repair of alkylation damage to nucleic acids. Crit Rev Biochem Mol Biol 2021; 56:125-136. [PMID: 33430640 DOI: 10.1080/10409238.2020.1869173] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
DNA damaging agents have been a cornerstone of cancer therapy for nearly a century. The discovery of many of these chemicals, particularly the alkylating agents, are deeply entwined with the development of poisonous materials originally intended for use in warfare. Over the last decades, their anti-proliferative effects have focused on the specific mechanisms by which they damage DNA, and the factors involved in the repair of such damage. Due to the variety of aberrant adducts created even for the simplest alkylating agents, numerous pathways of repair are engaged as a defense against this damage. More recent work has underscored the role of RNA damage in the cellular response to these agents, although the understanding of their role in relation to established DNA repair pathways is still in its infancy. In this review, we discuss the chemistry of alkylating agents, the numerous ways in which they damage nucleic acids, as well as the specific DNA and RNA repair pathways which are engaged to counter their effects.
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Affiliation(s)
- Ning Tsao
- Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, USA
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea.,Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
| | - Nima Mosammaparast
- Department of Pathology and Immunology, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO, USA
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19
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Oh J, Xu J, Chong J, Wang D. Molecular basis of transcriptional pausing, stalling, and transcription-coupled repair initiation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194659. [PMID: 33271312 DOI: 10.1016/j.bbagrm.2020.194659] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 12/24/2022]
Abstract
Transcription elongation by RNA polymerase II (Pol II) is constantly challenged by numerous types of obstacles that lead to transcriptional pausing or stalling. These obstacles include DNA lesions, DNA epigenetic modifications, DNA binding proteins, and non-B form DNA structures. In particular, lesion-induced prolonged transcriptional blockage or stalling leads to genome instability, cellular dysfunction, and cell death. Transcription-coupled nucleotide excision repair (TC-NER) pathway is the first line of defense that detects and repairs these transcription-blocking DNA lesions. In this review, we will first summarize the recent research progress toward understanding the molecular basis of transcriptional pausing and stalling by different kinds of obstacles. We will then discuss new insights into Pol II-mediated lesion recognition and the roles of CSB in TC-NER.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, United States; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, United States; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, United States.
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20
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Formation and Recognition of UV-Induced DNA Damage within Genome Complexity. Int J Mol Sci 2020; 21:ijms21186689. [PMID: 32932704 PMCID: PMC7555853 DOI: 10.3390/ijms21186689] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/09/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022] Open
Abstract
Ultraviolet (UV) light is a natural genotoxic agent leading to the formation of photolesions endangering the genomic integrity and thereby the survival of living organisms. To prevent the mutagenetic effect of UV, several specific DNA repair mechanisms are mobilized to accurately maintain genome integrity at photodamaged sites within the complexity of genome structures. However, a fundamental gap remains to be filled in the identification and characterization of factors at the nexus of UV-induced DNA damage, DNA repair, and epigenetics. This review brings together the impact of the epigenomic context on the susceptibility of genomic regions to form photodamage and focuses on the mechanisms of photolesions recognition through the different DNA repair pathways.
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21
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Liang S, Ezerskyte M, Wang J, Pelechano V, Dreij K. Transcriptional mutagenesis dramatically alters genome-wide p53 transactivation landscape. Sci Rep 2020; 10:13513. [PMID: 32782319 PMCID: PMC7419513 DOI: 10.1038/s41598-020-70412-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 07/27/2020] [Indexed: 11/29/2022] Open
Abstract
The transcriptional error rate can be significantly increased by the presence of DNA lesions that instruct mis-insertion during transcription; a process referred to as transcriptional mutagenesis (TM) that can result in altered protein function. Herein, we determined the effect of O6-methylguanine (O6-meG) on transcription and subsequent transactivation activity of p53 in human lung H1299 cells. Levels of TM and effects on transactivation were determined genome wide by RNA-seq. Results showed that 47% of all p53 transcripts contained an uridine misincorporation opposite the lesion at 6 h post transfection, which was decreased to 18% at 24 h. TM at these levels reduced DNA binding activity of p53 to 21% and 80% compared to wild type p53, respectively. Gene expression data were analysed to identify differentially expressed genes due to TM of p53. We show a temporal repression of transactivation of > 100 high confidence p53 target genes including regulators of the cell cycle, DNA damage response and apoptosis. In addition, TM repressed the transcriptional downregulation by p53 of several negative regulators of proliferation and differentiation. Our work demonstrates that TM, even when restricting its effect to an individual transcription factor, has the potential to alter gene expression programs and diversify cellular phenotypes.
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Affiliation(s)
- Shuo Liang
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Monika Ezerskyte
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77, Stockholm, Sweden.
| | - Jingwen Wang
- Science for Life Laboratory, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Vicent Pelechano
- Science for Life Laboratory, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Kristian Dreij
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77, Stockholm, Sweden.
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22
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Agapov A, Ignatov A, Turtola M, Belogurov G, Esyunina D, Kulbachinskiy A. Role of the trigger loop in translesion RNA synthesis by bacterial RNA polymerase. J Biol Chem 2020; 295:9583-9595. [PMID: 32439804 DOI: 10.1074/jbc.ra119.011844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
DNA lesions can severely compromise transcription and block RNA synthesis by RNA polymerase (RNAP), leading to subsequent recruitment of DNA repair factors to the stalled transcription complex. Recent structural studies have uncovered molecular interactions of several DNA lesions within the transcription elongation complex. However, little is known about the role of key elements of the RNAP active site in translesion transcription. Here, using recombinantly expressed proteins, in vitro transcription, kinetic analyses, and in vivo cell viability assays, we report that point amino acid substitutions in the trigger loop, a flexible element of the active site involved in nucleotide addition, can stimulate translesion RNA synthesis by Escherichia coli RNAP without altering the fidelity of nucleotide incorporation. We show that these substitutions also decrease transcriptional pausing and strongly affect the nucleotide addition cycle of RNAP by increasing the rate of nucleotide addition but also decreasing the rate of translocation. The secondary channel factors DksA and GreA modulated translesion transcription by RNAP, depending on changes in the trigger loop structure. We observed that although the mutant RNAPs stimulate translesion synthesis, their expression is toxic in vivo, especially under stress conditions. We conclude that the efficiency of translesion transcription can be significantly modulated by mutations affecting the conformational dynamics of the active site of RNAP, with potential effects on cellular stress responses and survival.
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Affiliation(s)
- Aleksei Agapov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Artem Ignatov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Matti Turtola
- Department of Biochemistry, University of Turku, Turku, Finland
| | | | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
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23
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RNA polymerase II stalls on oxidative DNA damage via a torsion-latch mechanism involving lone pair-π and CH-π interactions. Proc Natl Acad Sci U S A 2020; 117:9338-9348. [PMID: 32284409 DOI: 10.1073/pnas.1919904117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Oxidation of guanine generates several types of DNA lesions, such as 8-oxoguanine (8OG), 5-guanidinohydantoin (Gh), and spiroiminodihydantoin (Sp). These guanine-derived oxidative DNA lesions interfere with both replication and transcription. However, the molecular mechanism of transcription processing of Gh and Sp remains unknown. In this study, by combining biochemical and structural analysis, we revealed distinct transcriptional processing of these chemically related oxidized lesions: 8OG allows both error-free and error-prone bypass, whereas Gh or Sp causes strong stalling and only allows slow error-prone incorporation of purines. Our structural studies provide snapshots of how polymerase II (Pol II) is stalled by a nonbulky Gh lesion in a stepwise manner, including the initial lesion encounter, ATP binding, ATP incorporation, jammed translocation, and arrested states. We show that while Gh can form hydrogen bonds with adenosine monophosphate (AMP) during incorporation, this base pair hydrogen bonding is not sufficient to hold an ATP substrate in the addition site and is not stable during Pol II translocation after the chemistry step. Intriguingly, we reveal a unique structural reconfiguration of the Gh lesion in which the hydantoin ring rotates ∼90° and is perpendicular to the upstream base pair planes. The perpendicular hydantoin ring of Gh is stabilized by noncanonical lone pair-π and CH-π interactions, as well as hydrogen bonds. As a result, the Gh lesion, as a functional mimic of a 1,2-intrastrand crosslink, occupies canonical -1 and +1 template positions and compromises the loading of the downstream template base. Furthermore, we suggest Gh and Sp lesions are potential targets of transcription-coupled repair.
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24
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A facile & convenient route for the stereoselective synthesis of Z- isoxazol-5(4H)-ones derivatives catalysed by sodium acetate: Synthesis, multispectroscopic properties, crystal structure with DFT calculations, DNA-binding studies and molecular docking studies. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127067] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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25
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Prajapati RK, Rosenqvist P, Palmu K, Mäkinen JJ, Malinen AM, Virta P, Metsä-Ketelä M, Belogurov GA. Oxazinomycin arrests RNA polymerase at the polythymidine sequences. Nucleic Acids Res 2019; 47:10296-10312. [PMID: 31495891 PMCID: PMC6821320 DOI: 10.1093/nar/gkz782] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/13/2019] [Accepted: 08/31/2019] [Indexed: 02/06/2023] Open
Abstract
Oxazinomycin is a C-nucleoside antibiotic that is produced by Streptomyces hygroscopicus and closely resembles uridine. Here, we show that the oxazinomycin triphosphate is a good substrate for bacterial and eukaryotic RNA polymerases (RNAPs) and that a single incorporated oxazinomycin is rapidly extended by the next nucleotide. However, the incorporation of several successive oxazinomycins or a single oxazinomycin in a certain sequence context arrested a fraction of the transcribing RNAP. The addition of Gre RNA cleavage factors eliminated the transcriptional arrest at a single oxazinomycin and shortened the nascent RNAs arrested at the polythymidine sequences suggesting that the transcriptional arrest was caused by backtracking of RNAP along the DNA template. We further demonstrate that the ubiquitous C-nucleoside pseudouridine is also a good substrate for RNA polymerases in a triphosphorylated form but does not inhibit transcription of the polythymidine sequences. Our results collectively suggest that oxazinomycin functions as a Trojan horse substrate and its inhibitory effect is attributable to the oxygen atom in the position corresponding to carbon five of the uracil ring.
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Affiliation(s)
- Ranjit K Prajapati
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Petja Rosenqvist
- Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
| | - Kaisa Palmu
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Janne J Mäkinen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Anssi M Malinen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Pasi Virta
- Department of Chemistry, University of Turku, FIN-20014 Turku, Finland
| | - Mikko Metsä-Ketelä
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
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Brickner JR, Townley BA, Mosammaparast N. Intersections between transcription-coupled repair and alkylation damage reversal. DNA Repair (Amst) 2019; 81:102663. [PMID: 31326362 DOI: 10.1016/j.dnarep.2019.102663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The response to DNA damage intersects with many other physiological processes in the cell, such as DNA replication, chromatin remodeling, and the cell cycle. Certain damaging lesions, such as UV-induced pyrimidine dimers, also strongly block RNA polymerases, necessitating the coordination of the repair mechanism with remodeling of the elongating transcriptional machinery, in a process called transcription-coupled nucleotide excision repair (TC-NER). This pathway is typically not thought to be engaged with smaller lesions such as base alkylation. However, recent work has uncovered the potential for shared molecular components between the cellular response to alkylation and UV damage. Here, we review our current understanding of the alkylation damage response and its impacts on RNA biogenesis. We give particular attention to the Activating Signal Cointegrator Complex (ASCC), which plays important roles in the transcriptional response during UV damage as well as alkylation damage reversal, and intersects with trichothiodystrophy, an inherited disease associated with TC-NER.
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Affiliation(s)
- Joshua R Brickner
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Brittany A Townley
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Nima Mosammaparast
- Department of Pathology and Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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27
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Oh J, Xu J, Chong J, Wang D. Structural and biochemical analysis of DNA lesion-induced RNA polymerase II arrest. Methods 2019; 159-160:29-34. [PMID: 30797902 DOI: 10.1016/j.ymeth.2019.02.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/30/2019] [Accepted: 02/19/2019] [Indexed: 11/16/2022] Open
Abstract
Transcription, catalyzed by RNA polymerase II (Pol II) in eukaryotes, is the first step in gene expression. RNA Pol II is a 12-subunit enzyme complex regulated by many different transcription factors during transcription initiation, elongation, and termination. During elongation, Pol II encounters various types of obstacles that can cause transcriptional pausing and arrest. Through decades of research on transcriptional pausing, it is widely known that Pol II can distinguish between different types of obstacles by its active site. A major class of obstacles is DNA lesions. While some DNA lesions can cause transient transcriptional pausing, which can be bypassed by Pol II itself or with the help from other elongation factors, bulky DNA damage can cause prolonged transcriptional pausing and arrest, which signals for transcription coupled repair. Using biochemical and structural biology approaches, the outcomes of many different types of DNA lesions, DNA modifications, and DNA binding molecules to transcription were studied. In this mini review, we will describe the in vitro transcription assays with Pol II to investigate the impacts of various DNA lesions on transcriptional outcomes and the crystallization method of lesion-arrested Pol II complex. These methods can provide a general platform for the structural and biochemical analysis of Pol II transcriptional pausing and bypass mechanisms.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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28
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Turtola M, Mäkinen JJ, Belogurov GA. Active site closure stabilizes the backtracked state of RNA polymerase. Nucleic Acids Res 2018; 46:10870-10887. [PMID: 30256972 PMCID: PMC6237748 DOI: 10.1093/nar/gky883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/30/2018] [Accepted: 09/19/2018] [Indexed: 01/02/2023] Open
Abstract
All cellular RNA polymerases (RNAP) occasionally backtrack along the template DNA as part of transcriptional proofreading and regulation. Here, we studied the mechanism of RNAP backtracking by one nucleotide using two complementary approaches that allowed us to precisely measure the occupancy and lifetime of the backtracked state. Our data show that the stability of the backtracked state is critically dependent on the closure of the RNAP active site by a mobile domain, the trigger loop (TL). The lifetime and occupancy of the backtracked state measurably decreased by substitutions of the TL residues that interact with the nucleoside triphosphate (NTP) substrate, whereas amino acid substitutions that stabilized the closed active site increased the lifetime and occupancy. These results suggest that the same conformer of the TL closes the active site during catalysis of nucleotide incorporation into the nascent RNA and backtracking by one nucleotide. In support of this hypothesis, we construct a model of the 1-nt backtracked complex with the closed active site and the backtracked nucleotide in the entry pore area known as the E-site. We further propose that 1-nt backtracking mimics the reversal of the NTP substrate loading into the RNAP active site during on-pathway elongation.
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Affiliation(s)
- Matti Turtola
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
| | - Janne J Mäkinen
- University of Turku, Department of Biochemistry, FIN-20014 Turku, Finland
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29
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Hu CW, Cooke MS, Chang YJ, Chao MR. Direct-acting DNA ethylating agents associated with tobacco use primarily originate from the tobacco itself, not combustion. JOURNAL OF HAZARDOUS MATERIALS 2018; 358:397-404. [PMID: 30005251 DOI: 10.1016/j.jhazmat.2018.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 06/27/2018] [Accepted: 07/02/2018] [Indexed: 06/08/2023]
Abstract
Unburnt tobacco and tobacco smoke contain a variety of carcinogens, exposure to which are causally associated with the incidence of several human cancers. Herein, we used isotope-dilution LC-MS/MS for the quantification of alkylated purines in DNA, following in vitro exposure to aqueous extracts of tobacco itself, and tobacco smoke. Our results demonstrated the presence of direct-acting ethylating agent(s) in unburnt tobacco, which 4.0-6.3 times exceeded that in the particulate phase of sidestream cigarette smoke and 6.8-8.9 times exceeded that in mainstream smoke. Interestingly, particulate phase of sidestream cigarette smoke exhibited higher ethylating potency than that in mainstream smoke. This finding refutes the previous assumptions that the ethylating agent(s) associated with smoking, are derived from cigarette smoke. Indeed, our data show that combustion of tobacco actually decreases the ethylating potency of tobacco. Although the identity of this agent(s) remains unknown, our data suggest that it is highly hydrophilic, and hence likely to be easily extracted by saliva. This would allow intimate contact with the tissues of the oropharyngeal cavity. Taken together, these results have profound implications for tobacco use, in particular for tobacco chewers and passive smokers, whose exposure to ethylating agent(s) is greater than previously thought.
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Affiliation(s)
- Chiung-Wen Hu
- Department of Public Health, Chung Shan Medical University, Taichung 402, Taiwan; Oxidative Stress Group, Department of Environmental Health Sciences, Florida International University, Miami, FL 33199, USA
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Environmental Health Sciences, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Yuan-Jhe Chang
- Department of Occupational Safety and Health, Chung Shan Medical University, Taichung 402, Taiwan
| | - Mu-Rong Chao
- Oxidative Stress Group, Department of Environmental Health Sciences, Florida International University, Miami, FL 33199, USA; Department of Occupational Safety and Health, Chung Shan Medical University, Taichung 402, Taiwan; Department of Occupational Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan.
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30
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Structural basis of DNA lesion recognition for eukaryotic transcription-coupled nucleotide excision repair. DNA Repair (Amst) 2018; 71:43-55. [PMID: 30174298 DOI: 10.1016/j.dnarep.2018.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Eukaryotic transcription-coupled nucleotide excision repair (TC-NER) is a pathway that removes DNA lesions capable of blocking RNA polymerase II (Pol II) transcription from the template strand. This process is initiated by lesion-arrested Pol II and the recruitment of Cockayne Syndrome B protein (CSB). In this review, we will focus on the lesion recognition steps of eukaryotic TC-NER and summarize the recent research progress toward understanding the structural basis of Pol II-mediated lesion recognition and Pol II-CSB interactions. We will discuss the roles of CSB in both TC-NER initiation and transcription elongation. Finally, we propose an updated model of tripartite lesion recognition and verification for TC-NER in which CSB ensures Pol II-mediated recognition of DNA lesions for TC-NER.
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31
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O6-methylguanine-induced transcriptional mutagenesis reduces p53 tumor-suppressor function. Proc Natl Acad Sci U S A 2018; 115:4731-4736. [PMID: 29666243 PMCID: PMC5939098 DOI: 10.1073/pnas.1721764115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The impact of DNA lesions on replication and mutagenesis is of high relevance for human health; however, the role of lesion-induced transcriptional mutagenesis (TM) in disease development is unknown. Here, the impact of O6-methylguanine–induced TM on p53 function as a tumor suppressor was investigated in human cells. Results showed that TM in 15% of the transcripts resulted in a reduced ability of p53 protein to transactivate genes that regulate cell-cycle arrest and induction of apoptosis. This resulted in the loss of functional cell-cycle checkpoints and in impaired activation of apoptosis, both canonical p53 tumor-suppressor functions. This work provides evidence that TM can induce phenotypic changes in mammalian cells that have important implications for its role in tumorigenesis. Altered protein function due to mutagenesis plays an important role in disease development. This is perhaps most evident in tumorigenesis and the associated loss or gain of function of tumor-suppressor genes and oncogenes. The extent to which lesion-induced transcriptional mutagenesis (TM) influences protein function and its contribution to the development of disease is not well understood. In this study, the impact of O6-methylguanine on the transcription fidelity of p53 and the subsequent effects on the protein’s function as a regulator of cell death and cell-cycle arrest were examined in human cells. Levels of TM were determined by RNA-sequencing. In cells with active DNA repair, misincorporation of uridine opposite the lesion occurred in 0.14% of the transcripts and increased to 14.7% when repair by alkylguanine–DNA alkyltransferase was compromised. Expression of the dominant-negative p53 R248W mutant due to TM significantly reduced the transactivation of several established p53 target genes that mediate the tumor-suppressor function, including CDKN1A (p21) and BBC3 (PUMA). This resulted in deregulated signaling through the retinoblastoma protein and loss of G1/S cell-cycle checkpoint function. In addition, we observed impaired activation of apoptosis coupled to the reduction of the tumor-suppressor functions of p53. Taking these findings together, this work provides evidence that TM can induce phenotypic changes in mammalian cells that have important implications for the role of TM in tumorigenesis.
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32
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Wang W, Walmacq C, Chong J, Kashlev M, Wang D. Structural basis of transcriptional stalling and bypass of abasic DNA lesion by RNA polymerase II. Proc Natl Acad Sci U S A 2018; 115:E2538-E2545. [PMID: 29487211 PMCID: PMC5856558 DOI: 10.1073/pnas.1722050115] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Abasic sites are among the most abundant DNA lesions and interfere with DNA replication and transcription, but the mechanism of their action on transcription remains unknown. Here we applied a combined structural and biochemical approach for a comprehensive investigation of how RNA polymerase II (Pol II) processes an abasic site, leading to slow bypass of lesion. Encounter of Pol II with an abasic site involves two consecutive slow steps: insertion of adenine opposite a noninstructive abasic site (the A-rule), followed by extension of the 3'-rAMP with the next cognate nucleotide. Further studies provided structural insights into the A-rule: ATP is slowly incorporated into RNA in the absence of template guidance. Our structure revealed that ATP is bound to the Pol II active site, whereas the abasic site is located at an intermediate state above the Bridge Helix, a conserved structural motif that is cirtical for Pol II activity. The next extension step occurs in a template-dependent manner where a cognate substrate is incorporated, despite at a much slower rate compared with nondamaged template. During the extension step, neither the cognate substrate nor the template base is located at the canonical position, providing a structural explanation as to why this step is as slow as the insertion step. Taken together, our studies provide a comprehensive understanding of Pol II stalling and bypass of the abasic site in the DNA template.
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Affiliation(s)
- Wei Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Celine Walmacq
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Mikhail Kashlev
- Center for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093
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