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Lin SM, Huang HT, Fang PJ, Chang CF, Satange R, Chang CK, Chou SH, Neidle S, Hou MH. Structural basis of water-mediated cis Watson-Crick/Hoogsteen base-pair formation in non-CpG methylation. Nucleic Acids Res 2024; 52:8566-8579. [PMID: 38989613 DOI: 10.1093/nar/gkae594] [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] [Received: 01/25/2024] [Revised: 05/30/2024] [Accepted: 06/28/2024] [Indexed: 07/12/2024] Open
Abstract
Non-CpG methylation is associated with several cellular processes, especially neuronal development and cancer, while its effect on DNA structure remains unclear. We have determined the crystal structures of DNA duplexes containing -CGCCG- regions as CCG repeat motifs that comprise a non-CpG site with or without cytosine methylation. Crystal structure analyses have revealed that the mC:G base-pair can simultaneously form two alternative conformations arising from non-CpG methylation, including a unique water-mediated cis Watson-Crick/Hoogsteen, (w)cWH, and Watson-Crick (WC) geometries, with partial occupancies of 0.1 and 0.9, respectively. NMR studies showed that an alternative conformation of methylated mC:G base-pair at non-CpG step exhibits characteristics of cWH with a syn-guanosine conformation in solution. DNA duplexes complexed with the DNA binding drug echinomycin result in increased occupancy of the (w)cWH geometry in the methylated base-pair (from 0.1 to 0.3). Our structural results demonstrated that cytosine methylation at a non-CpG step leads to an anti→syntransition of its complementary guanosine residue toward the (w)cWH geometry as a partial population of WC, in both drug-bound and naked mC:G base pairs. This particular geometry is specific to non-CpG methylated dinucleotide sites in B-form DNA. Overall, the current study provides new insights into DNA conformation during epigenetic regulation.
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Affiliation(s)
- Shan-Meng Lin
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Hsiang-Ti Huang
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Pei-Ju Fang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chi-Fon Chang
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Roshan Satange
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Chung-Ke Chang
- Taiwan Biobank, Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Shan-Ho Chou
- Institute of Biochemistry, National Chung Hsing University, Taichung 402, Taiwan
| | - Stephen Neidle
- School of Pharmacy, University College London, London WC1N 1AX, UK
| | - Ming-Hon Hou
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
- Doctoral Program in Medical Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
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Tsuruta M, Sugitani Y, Sugimoto N, Miyoshi D. Combined Effects of Methylated Cytosine and Molecular Crowding on the Thermodynamic Stability of DNA Duplexes. Int J Mol Sci 2021; 22:ijms22020947. [PMID: 33477917 PMCID: PMC7833394 DOI: 10.3390/ijms22020947] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/31/2022] Open
Abstract
Methylated cytosine within CpG dinucleotides is a key factor for epigenetic gene regulation. It has been revealed that methylated cytosine decreases DNA backbone flexibility and increases the thermal stability of DNA. Although the molecular environment is an important factor for the structure, thermodynamics, and function of biomolecules, there are few reports on the effects of methylated cytosine under a cell-mimicking molecular environment. Here, we systematically investigated the effects of methylated cytosine on the thermodynamics of DNA duplexes under molecular crowding conditions, which is a critical difference between the molecular environment in cells and test tubes. Thermodynamic parameters quantitatively demonstrated that the methylation effect and molecular crowding effect on DNA duplexes are independent and additive, in which the degree of the stabilization is the sum of the methylation effect and molecular crowding effect. Furthermore, the effects of methylation and molecular crowding correlate with the hydration states of DNA duplexes. The stabilization effect of methylation was due to the favorable enthalpic contribution, suggesting that direct interactions of the methyl group with adjacent bases and adjacent methyl groups play a role in determining the flexibility and thermodynamics of DNA duplexes. These results are useful to predict the properties of DNA duplexes with methylation in cell-mimicking conditions.
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Affiliation(s)
- Mitsuki Tsuruta
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
| | - Yui Sugitani
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
| | - Naoki Sugimoto
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe 650-0047, Japan
| | - Daisuke Miyoshi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
- Correspondence: ; Tel.: +81-(07)-8303-1426
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Hawner M, Ducho C. Cellular Targeting of Oligonucleotides by Conjugation with Small Molecules. Molecules 2020; 25:E5963. [PMID: 33339365 PMCID: PMC7766908 DOI: 10.3390/molecules25245963] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 12/20/2022] Open
Abstract
Drug candidates derived from oligonucleotides (ON) are receiving increased attention that is supported by the clinical approval of several ON drugs. Such therapeutic ON are designed to alter the expression levels of specific disease-related proteins, e.g., by displaying antigene, antisense, and RNA interference mechanisms. However, the high polarity of the polyanionic ON and their relatively rapid nuclease-mediated cleavage represent two major pharmacokinetic hurdles for their application in vivo. This has led to a range of non-natural modifications of ON structures that are routinely applied in the design of therapeutic ON. The polyanionic architecture of ON often hampers their penetration of target cells or tissues, and ON usually show no inherent specificity for certain cell types. These limitations can be overcome by conjugation of ON with molecular entities mediating cellular 'targeting', i.e., enhanced accumulation at and/or penetration of a specific cell type. In this context, the use of small molecules as targeting units appears particularly attractive and promising. This review provides an overview of advances in the emerging field of cellular targeting of ON via their conjugation with small-molecule targeting structures.
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Affiliation(s)
| | - Christian Ducho
- Department of Pharmacy, Pharmaceutical and Medicinal Chemistry, Saarland University, Campus C2 3, 66 123 Saarbrücken, Germany;
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Dostal V, Churchill MEA. Cytosine methylation of mitochondrial DNA at CpG sequences impacts transcription factor A DNA binding and transcription. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2019; 1862:598-607. [PMID: 30807854 PMCID: PMC7806247 DOI: 10.1016/j.bbagrm.2019.01.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 12/22/2022]
Abstract
In eukaryotes, cytosine methylation of nuclear DNA at CpG sequences (5mCpG) regulates epigenetic inheritance through alterations in chromatin structure. However, mitochondria lack nucleosomal chromatin, therefore the molecular mechanisms by which 5mCpG influences mitochondria must be different and are as yet unknown. Mitochondrial Transcription Factor A (TFAM) is both the primary DNA-compacting protein in the mitochondrial DNA (mtDNA) nucleoid and a transcription-initiation factor. TFAM must encounter hundreds of CpGs in mtDNA, so the occurrence of 5mCpG has the potential to impact TFAM-DNA recognition. We used biophysical approaches to determine whether 5mCpG alters any TFAM-dependent activities. 5mCpG in the heavy strand promoter (HSP1) increased the binding affinity of TFAM and induced TFAM multimerization with increased cooperativity compared to nonmethylated DNA. However, 5mCpG had no apparent effect on TFAM-dependent DNA compaction. Additionally, 5mCpG had a clear and context-dependent effect on transcription initiating from the three mitochondrial promoters. Taken together, our findings demonstrate that 5mCpG in the mitochondrial promoter region does impact TFAM-dependent activities in vitro.
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Affiliation(s)
- Vishantie Dostal
- Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mair E A Churchill
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA; Program in Structural Biology and Biochemistry, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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Liu CD, Wang JH, Xie Y, Chen H. Synthesis and DNA/RNA complementation studies of peptide nucleic acids containing 5-halouracils. MEDCHEMCOMM 2017; 8:385-389. [PMID: 30108754 PMCID: PMC6071789 DOI: 10.1039/c6md00536e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/09/2016] [Indexed: 01/02/2023]
Abstract
The monomers of peptide nucleic acids containing 5-halouracils (5-XU-PNA), incorporated into heptameric PNA in the middle position, have been synthesized. Thermodynamic analyses revealed that the heptameric PNA oligomer with DNA and RNA showed higher duplex stability compared to the unmodified PNA counterpart. NMR studies suggested that the electron withdrawing effect of the halogen atom increased the strength of the XU-A hydrogen bond.
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Affiliation(s)
- Chun-Dong Liu
- Key Laboratory of Biorheological Science and Technology , Ministry of Education , College of Bioengineering , Chongqing University , Chongqing , 400044 , China . ; ; Tel: +86 23 65102507
| | - Jian-Hua Wang
- Key Laboratory of Biorheological Science and Technology , Ministry of Education , College of Bioengineering , Chongqing University , Chongqing , 400044 , China . ; ; Tel: +86 23 65102507
| | - Yang Xie
- Key Laboratory of Biorheological Science and Technology , Ministry of Education , College of Bioengineering , Chongqing University , Chongqing , 400044 , China . ; ; Tel: +86 23 65102507
| | - Hang Chen
- Key Laboratory of Biorheological Science and Technology , Ministry of Education , College of Bioengineering , Chongqing University , Chongqing , 400044 , China . ; ; Tel: +86 23 65102507
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Yu Y, Cui Y, Niedernhofer LJ, Wang Y. Occurrence, Biological Consequences, and Human Health Relevance of Oxidative Stress-Induced DNA Damage. Chem Res Toxicol 2016; 29:2008-2039. [PMID: 27989142 DOI: 10.1021/acs.chemrestox.6b00265] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A variety of endogenous and exogenous agents can induce DNA damage and lead to genomic instability. Reactive oxygen species (ROS), an important class of DNA damaging agents, are constantly generated in cells as a consequence of endogenous metabolism, infection/inflammation, and/or exposure to environmental toxicants. A wide array of DNA lesions can be induced by ROS directly, including single-nucleobase lesions, tandem lesions, and hypochlorous acid (HOCl)/hypobromous acid (HOBr)-derived DNA adducts. ROS can also lead to lipid peroxidation, whose byproducts can also react with DNA to produce exocyclic DNA lesions. A combination of bioanalytical chemistry, synthetic organic chemistry, and molecular biology approaches have provided significant insights into the occurrence, repair, and biological consequences of oxidatively induced DNA lesions. The involvement of these lesions in the etiology of human diseases and aging was also investigated in the past several decades, suggesting that the oxidatively induced DNA adducts, especially bulky DNA lesions, may serve as biomarkers for exploring the role of oxidative stress in human diseases. The continuing development and improvement of LC-MS/MS coupled with the stable isotope-dilution method for DNA adduct quantification will further promote research about the clinical implications and diagnostic applications of oxidatively induced DNA adducts.
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Affiliation(s)
| | | | - Laura J Niedernhofer
- Department of Metabolism and Aging, The Scripps Research Institute Florida , Jupiter, Florida 33458, United States
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Intrinsic mutagenic properties of 5-chlorocytosine: A mechanistic connection between chronic inflammation and cancer. Proc Natl Acad Sci U S A 2015; 112:E4571-80. [PMID: 26243878 DOI: 10.1073/pnas.1507709112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
During chronic inflammation, neutrophil-secreted hypochlorous acid can damage nearby cells inducing the genomic accumulation of 5-chlorocytosine (5ClC), a known inflammation biomarker. Although 5ClC has been shown to promote epigenetic changes, it has been unknown heretofore if 5ClC directly perpetrates a mutagenic outcome within the cell. The present work shows that 5ClC is intrinsically mutagenic, both in vitro and, at a level of a single molecule per cell, in vivo. Using biochemical and genetic approaches, we have quantified the mutagenic and toxic properties of 5ClC, showing that this lesion caused C→T transitions at frequencies ranging from 3-9% depending on the polymerase traversing the lesion. X-ray crystallographic studies provided a molecular basis for the mutagenicity of 5ClC; a snapshot of human polymerase β replicating across a primed 5ClC-containing template uncovered 5ClC engaged in a nascent base pair with an incoming dATP analog. Accommodation of the chlorine substituent in the template major groove enabled a unique interaction between 5ClC and the incoming dATP, which would facilitate mutagenic lesion bypass. The type of mutation induced by 5ClC, the C→T transition, has been previously shown to occur in substantial amounts both in tissues under inflammatory stress and in the genomes of many inflammation-associated cancers. In fact, many sequence-specific mutational signatures uncovered in sequenced cancer genomes feature C→T mutations. Therefore, the mutagenic ability of 5ClC documented in the present study may constitute a direct functional link between chronic inflammation and the genetic changes that enable and promote malignant transformation.
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Gorczak N, Fujii T, Mishra AK, Houtepen AJ, Grozema FC, Lewis FD. Mechanism and Dynamics of Electron Injection and Charge Recombination in DNA. Dependence on Neighboring Pyrimidines. J Phys Chem B 2015; 119:7673-80. [DOI: 10.1021/jp512113w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Natalie Gorczak
- Department of Chemical
Engineering, Delft University of Technology, 2628 BL Delft, The Netherlands
| | - Taiga Fujii
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ashutosh Kumar Mishra
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Arjan J. Houtepen
- Department of Chemical
Engineering, Delft University of Technology, 2628 BL Delft, The Netherlands
| | - Ferdinand C. Grozema
- Department of Chemical
Engineering, Delft University of Technology, 2628 BL Delft, The Netherlands
| | - Frederick D. Lewis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
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9
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Tao H, Yang JJ, Shi KH, Deng ZY, Li J. DNA methylation in cardiac fibrosis: new advances and perspectives. Toxicology 2014; 323:125-9. [PMID: 25017140 DOI: 10.1016/j.tox.2014.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/08/2014] [Accepted: 07/09/2014] [Indexed: 01/22/2023]
Abstract
Cardiac fibrosis is characterized by net accumulation of extracellular matrix (ECM) proteins in the cardiac interstitium, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. More specifically, cardiac fibroblasts are activated by a variety of pathological stimuli, thereby undergoing proliferation, differentiation to myofibroblasts, and production of various cytokines and ECM proteins. Thus, understanding the biological processes of cardiac fibroblasts will provide novel insights into the underlying mechanisms of cardiac fibrosis. DNA methylation is an important epigenetic mechanism, which often occurs in response to environmental stimuli and is crucial in regulating gene expression. The aberrant methylation of CpG island promoters of selected genes is the prominent epigenetic mechanism by which gene transcription can be effectively silenced. Aberrant hypermethylation of a few selected genes such as RASSF1A plays an important role in facilitating fibrotic fibroblast activation and in driving fibrosis. In this review we will discuss the mechanisms of DNA methylation and their implications for cardiac fibroblasts activation and fibrosis. Control of DNA methylation may serve as a new strategy for anti-fibrotic therapy.
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Affiliation(s)
- Hui Tao
- Department of Cardiothoracic Surgery, The Second Hospital of Anhui Medical University, Hefei 230601, China; Cardiovascular Research Center, Anhui Medical University, Hefei 230601, China
| | - Jing-Jing Yang
- Department of Pharmacology, The Second Hospital of Anhui Medical University, Hefei 230601, China; School of Pharmacy, Anhui Medical University, Hefei 230032, China
| | - Kai-Hu Shi
- Department of Cardiothoracic Surgery, The Second Hospital of Anhui Medical University, Hefei 230601, China; Cardiovascular Research Center, Anhui Medical University, Hefei 230601, China.
| | - Zi-Yu Deng
- Department of Scientific and Educational, The Second Hospital of Anhui Medical University, Hefei 230032, China.
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei 230032, China.
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