1
|
Zhou J, Chen Q, Ren R, Yang J, Liu B, Horton JR, Chang C, Li C, Maksoud L, Yang Y, Rotili D, Zhang X, Blumenthal RM, Chen T, Gao Y, Valente S, Mai A, Cheng X. Quinoline-based compounds can inhibit diverse enzymes that act on DNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587980. [PMID: 38617249 PMCID: PMC11014617 DOI: 10.1101/2024.04.03.587980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
DNA methylation, as exemplified by cytosine-C5 methylation in mammals and adenine-N6 methylation in bacteria, is a crucial epigenetic mechanism driving numerous vital biological processes. Developing non-nucleoside inhibitors to cause DNA hypomethylation is a high priority, in order to treat a variety of significant medical conditions without the toxicities associated with existing cytidine-based hypomethylating agents. In this study, we have characterized fifteen quinoline-based analogs. Notably, compounds with additions like a methylamine ( 9 ) or methylpiperazine ( 11 ) demonstrate similar low micromolar inhibitory potency against both human DNMT1 (which generates C5-methylcytosine) and Clostridioides difficile CamA (which generates N6-methyladenine). Structurally, compounds 9 and 11 specifically intercalate into CamA-bound DNA via the minor groove, adjacent to the target adenine, leading to a substantial conformational shift that moves the catalytic domain away from the DNA. This study adds to the limited examples of DNA methyltransferases being inhibited by non-nucleotide compounds through DNA intercalation, following the discovery of dicyanopyridine-based inhibitors for DNMT1. Furthermore, our study shows that some of these quinoline-based analogs inhibit other enzymes that act on DNA, such as polymerases and base excision repair glycosylases. Finally, in cancer cells compound 11 elicits DNA damage response via p53 activation. Abstract Figure Highlights Six of fifteen quinoline-based derivatives demonstrated comparable low micromolar inhibitory effects on human cytosine methyltransferase DNMT1, and the bacterial adenine methyltransferases Clostridioides difficile CamA and Caulobacter crescentus CcrM. Compounds 9 and 11 were found to intercalate into a DNA substrate bound by CamA. These quinoline-based derivatives also showed inhibitory activity against various base excision repair DNA glycosylases, and DNA and RNA polymerases. Compound 11 provokes DNA damage response via p53 activation in cancer cells.
Collapse
|
2
|
Torres JR, Lescano López I, Ayala AM, Alvarez ME. The Arabidopsis DNA glycosylase MBD4L repairs the nuclear genome in vivo. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1633-1646. [PMID: 37278489 DOI: 10.1111/tpj.16344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/02/2023] [Indexed: 06/07/2023]
Abstract
DNA glycosylases remove mispaired or modified bases from DNA initiating the base excision repair (BER) pathway. The DNA glycosylase MBD4 (methyl-CpG-binding domain protein 4) has been functionally characterized in mammals, but not yet in plants, where it is called MBD4-like (MBD4L). Mammalian MBD4 and Arabidopsis recombinant MBD4L excise U and T mispaired with G, as well as 5-fluorouracil (5-FU) and 5-bromouracil (5-BrU) in vitro. Here, we investigate the ability of Arabidopsis MBD4L to remove some of these substrates from the nuclear genome in vivo in coordination with uracil DNA glycosylase (AtUNG). We found that mbd4l mutants are hypersensitive to 5-FU and 5-BrU, as they displayed smaller size, less root growth, and higher cell death than control plants in both media. Using comet assays, we determined BER-associated DNA fragmentation in isolated nuclei and observed reduced DNA breaks in mbd4l plants under both conditions, but particularly with 5-BrU. The use of ung and ung x mbd4l mutants in these assays indicated that both MBD4L and AtUNG trigger nuclear DNA fragmentation in response to 5-FU. Consistently, we here report the nuclear localization of AtUNG based on the expression of AtUNG-GFP/RFP constructs in transgenic plants. Interestingly, MBD4L and AtUNG are transcriptionally coordinated but display not completely overlapping functions. MBD4L-deficient plants showed reduced expression of BER genes and enhanced expression of DNA damage response (DDR) gene markers. Overall, our findings indicate that Arabidopsis MBD4L is critical for maintaining nuclear genome integrity and preventing cell death under genotoxic stress conditions.
Collapse
Affiliation(s)
- José Roberto Torres
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina
| | - Ignacio Lescano López
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina
| | - Ana María Ayala
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina
| | - María Elena Alvarez
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba, X5000HUA, Argentina
| |
Collapse
|
3
|
Nikkel DJ, Wetmore SD. Distinctive Formation of a DNA-Protein Cross-Link during the Repair of DNA Oxidative Damage: Insights into Human Disease from MD Simulations and QM/MM Calculations. J Am Chem Soc 2023. [PMID: 37285289 DOI: 10.1021/jacs.3c01773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Reactive oxygen species damage DNA and result in health issues. The major damage product, 8-oxo-7,8-dihydroguanine (8oG), is repaired by human adenine DNA glycosylase homologue (MUTYH). Although MUTYH misfunction is associated with a genetic disorder called MUTYH-associated polyposis (MAP) and MUTYH is a potential target for cancer drugs, the catalytic mechanism required to develop disease treatments is debated in the literature. This study uses molecular dynamics simulations and quantum mechanics/molecular mechanics techniques initiated from DNA-protein complexes that represent different stages of the repair pathway to map the catalytic mechanism of the wild-type MUTYH bacterial homologue (MutY). This multipronged computational approach characterizes a DNA-protein cross-linking mechanism that is consistent with all previous experimental data and is a distinct pathway across the broad class of monofunctional glycosylase repair enzymes. In addition to clarifying how the cross-link is formed, accommodated by the enzyme, and hydrolyzed for product release, our calculations rationalize why cross-link formation is favored over immediate glycosidic bond hydrolysis, the accepted mechanism for all other monofunctional DNA glycosylases to date. Calculations on the Y126F mutant MutY highlight critical roles for active site residues throughout the reaction, while investigation of the N146S mutant rationalizes the connection between the analogous N224S MUTYH mutation and MAP. In addition to furthering our knowledge of the chemistry associated with a devastating disorder, the structural information gained about the distinctive MutY mechanism compared to other repair enzymes represents an important step for the development of specific and potent small-molecule inhibitors as cancer therapeutics.
Collapse
Affiliation(s)
- Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| |
Collapse
|
4
|
Hung SH, Elliott GI, Ramkumar TR, Burtnyak L, McGrenaghan CJ, Alkuzweny S, Quaiyum S, Iwata-Reuyl D, Pan X, Green BD, Kelly VP, de Crécy-Lagard V, Swairjo M. Structural basis of Qng1-mediated salvage of the micronutrient queuine from queuosine-5'-monophosphate as the biological substrate. Nucleic Acids Res 2023; 51:935-951. [PMID: 36610787 PMCID: PMC9881137 DOI: 10.1093/nar/gkac1231] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 12/02/2022] [Accepted: 12/10/2022] [Indexed: 01/09/2023] Open
Abstract
Eukaryotic life benefits from-and ofttimes critically relies upon-the de novo biosynthesis and supply of vitamins and micronutrients from bacteria. The micronutrient queuosine (Q), derived from diet and/or the gut microbiome, is used as a source of the nucleobase queuine, which once incorporated into the anticodon of tRNA contributes to translational efficiency and accuracy. Here, we report high-resolution, substrate-bound crystal structures of the Sphaerobacter thermophilus queuine salvage protein Qng1 (formerly DUF2419) and of its human ortholog QNG1 (C9orf64), which together with biochemical and genetic evidence demonstrate its function as the hydrolase releasing queuine from queuosine-5'-monophosphate as the biological substrate. We also show that QNG1 is highly expressed in the liver, with implications for Q salvage and recycling. The essential role of this family of hydrolases in supplying queuine in eukaryotes places it at the nexus of numerous (patho)physiological processes associated with queuine deficiency, including altered metabolism, proliferation, differentiation and cancer progression.
Collapse
Affiliation(s)
- Shr-Hau Hung
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
- The Viral Information Institute, San Diego State University, San Diego, CA, USA
| | - Gregory I Elliott
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Thakku R Ramkumar
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Lyubomyr Burtnyak
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Callum J McGrenaghan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Sana Alkuzweny
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Samia Quaiyum
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, PO Box 751 Portland State University, Portland, OR 97207, USA
| | - Xiaobei Pan
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Brian D Green
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Vincent P Kelly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
- University of Florida Genetics Institute, Gainesville, FL 32610, USA
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
- The Viral Information Institute, San Diego State University, San Diego, CA, USA
| |
Collapse
|
5
|
Baljinnyam T, Sowers ML, Hsu CW, Conrad JW, Herring JL, Hackfeld LC, Sowers LC. Chemical and enzymatic modifications of 5-methylcytosine at the intersection of DNA damage, repair, and epigenetic reprogramming. PLoS One 2022; 17:e0273509. [PMID: 36037209 PMCID: PMC9423628 DOI: 10.1371/journal.pone.0273509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 08/09/2022] [Indexed: 11/19/2022] Open
Abstract
The DNA of all living organisms is persistently damaged by endogenous reactions including deamination and oxidation. Such damage, if not repaired correctly, can result in mutations that drive tumor development. In addition to chemical damage, recent studies have established that DNA bases can be enzymatically modified, generating many of the same modified bases. Irrespective of the mechanism of formation, modified bases can alter DNA-protein interactions and therefore modulate epigenetic control of gene transcription. The simultaneous presence of both chemically and enzymatically modified bases in DNA suggests a potential intersection, or collision, between DNA repair and epigenetic reprogramming. In this paper, we have prepared defined sequence oligonucleotides containing the complete set of oxidized and deaminated bases that could arise from 5-methylcytosine. We have probed these substrates with human glycosylases implicated in DNA repair and epigenetic reprogramming. New observations reported here include: SMUG1 excises 5-carboxyuracil (5caU) when paired with A or G. Both TDG and MBD4 cleave 5-formyluracil and 5caU when mispaired with G. Further, TDG not only removes 5-formylcytosine and 5-carboxycytosine when paired with G, but also when mispaired with A. Surprisingly, 5caU is one of the best substrates for human TDG, SMUG1 and MBD4, and a much better substrate than T. The data presented here introduces some unexpected findings that pose new questions on the interactions between endogenous DNA damage, repair, and epigenetic reprogramming pathways.
Collapse
Affiliation(s)
- Tuvshintugs Baljinnyam
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Mark L. Sowers
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Chia Wei Hsu
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - James W. Conrad
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jason L. Herring
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Linda C. Hackfeld
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lawrence C. Sowers
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
| |
Collapse
|
6
|
Westwood MN, Johnson CC, Oyler NA, Meints GA. Kinetics and thermodynamics of BI-BII interconversion altered by T:G mismatches in DNA. Biophys J 2022; 121:1691-1703. [PMID: 35367235 PMCID: PMC9117933 DOI: 10.1016/j.bpj.2022.03.031] [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: 08/30/2021] [Revised: 10/26/2021] [Accepted: 03/28/2022] [Indexed: 11/19/2022] Open
Abstract
T:G mismatches in DNA result in humans primarily from deamination of methylated CpG sites. They are repaired by redundant systems, such as thymine DNA glycosylase (TDG) and methyl-binding domain enzyme (MBD4), and maintenance of these sites has been implicated in epigenetic processes. The process by which these enzymes identify a canonical DNA base in the incorrect basepairing context remains a mystery. However, the conserved contacts of the repair enzymes with the DNA backbone suggests a role for protein-phosphate interaction in the recognition and repair processes. We have used 31P NMR to investigate the energetics of DNA backbone BI-BII interconversion, and for this work have focused on alterations to the activation barriers to interconversion and the effect of a mismatch compared with canonical DNA. We have found that alterations to the ΔG of interconversion for T:G basepairs are remarkably similar to U:G basepairs in the form of stepwise differences in ΔG of 1-2 kcal/mol greater than equivalent steps in unmodified DNA, suggesting a universality of this result for TDG substrates. Likewise, we see perturbations to the free energy (∼1 kcal/mol) and enthalpy (2-5 kcal/mol) of activation for the BI-BII interconversion localized to the phosphates flanking the mismatch. Overall our results strongly suggest that the perturbed backbone energetics in T:G basepairs play a significant role in the recognition process of DNA repair enzymes.
Collapse
Affiliation(s)
- M N Westwood
- Department of Chemistry and Biochemistry, Missouri State University, Springfield, Missouri
| | - C C Johnson
- Department of Chemistry and Biochemistry, Missouri State University, Springfield, Missouri
| | - Nathan A Oyler
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri
| | - Gary A Meints
- Department of Chemistry and Biochemistry, Missouri State University, Springfield, Missouri.
| |
Collapse
|
7
|
Yang J, Gupta E, Horton JR, Blumenthal RM, Zhang X, Cheng X. Differential ETS1 binding to T:G mismatches within a CpG dinucleotide contributes to C-to-T somatic mutation rate of the IDH2 hotspot at codon Arg140. DNA Repair (Amst) 2022; 113:103306. [PMID: 35255310 PMCID: PMC9411267 DOI: 10.1016/j.dnarep.2022.103306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 12/16/2022]
Abstract
Cytosine to thymine (C>T) somatic mutation is highly enriched in certain types of cancer, and most commonly occurs via deamination of a 5-methylcytosine (5mC) to thymine, in the context of a CpG dinucleotide. In theory, deamination should occur at equal rates to both 5mC nucleotides on opposite strands. In most cases, the resulting T:G or G:T mismatch can be repaired by thymine DNA glycosylase activities. However, while some hotspot-associated CpG mutations have approximately equal numbers of mutations that resulted either from C>T or G>A in a CpG dinucleotide, many showed strand bias, being skewed toward C>T of the first base pair or G>A of the second base pair. Using the IDH2 Arg140 codon as a case study, we show that the two possible T:G mismatches at the codon-specific CpG site have differing effects on transcription factor ETS1 binding affinity, differentially affecting access of a repair enzyme (MBD4) to the deamination-caused T:G mismatch. Our study thus provides a plausible mechanism for exclusion of repair enzymes by the differential binding of transcription factors affecting the rate at which the antecedent opposite-strand mutations occur.
Collapse
Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Esha Gupta
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA.
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| |
Collapse
|
8
|
Proteins That Read DNA Methylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:269-293. [DOI: 10.1007/978-3-031-11454-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
9
|
Trasviña-Arenas CH, Demir M, Lin WJ, David SS. Structure, function and evolution of the Helix-hairpin-Helix DNA glycosylase superfamily: Piecing together the evolutionary puzzle of DNA base damage repair mechanisms. DNA Repair (Amst) 2021; 108:103231. [PMID: 34649144 DOI: 10.1016/j.dnarep.2021.103231] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
The Base Excision Repair (BER) pathway is a highly conserved DNA repair system targeting chemical base modifications that arise from oxidation, deamination and alkylation reactions. BER features lesion-specific DNA glycosylases (DGs) which recognize and excise modified or inappropriate DNA bases to produce apurinic/apyrimidinic (AP) sites and coordinate AP-site hand-off to subsequent BER pathway enzymes. The DG superfamilies identified have evolved independently to cope with a wide variety of nucleobase chemical modifications. Most DG superfamilies recognize a distinct set of structurally related lesions. In contrast, the Helix-hairpin-Helix (HhH) DG superfamily has the remarkable ability to act upon structurally diverse sets of base modifications. The versatility in substrate recognition of the HhH-DG superfamily has been shaped by motif and domain acquisitions during evolution. In this paper, we review the structural features and catalytic mechanisms of the HhH-DG superfamily and draw a hypothetical reconstruction of the evolutionary path where these DGs developed diverse and unique enzymatic features.
Collapse
Affiliation(s)
| | - Merve Demir
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A
| | - Wen-Jen Lin
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A
| | - Sheila S David
- Department of Chemistry, University of California, Davis, CA 95616, U.S.A..
| |
Collapse
|
10
|
Pidugu LS, Bright H, Lin WJ, Majumdar C, Van Ostrand RP, David SS, Pozharski E, Drohat AC. Structural Insights into the Mechanism of Base Excision by MBD4. J Mol Biol 2021; 433:167097. [PMID: 34107280 PMCID: PMC8286355 DOI: 10.1016/j.jmb.2021.167097] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/24/2021] [Accepted: 06/01/2021] [Indexed: 11/28/2022]
Abstract
DNA glycosylases remove damaged or modified nucleobases by cleaving the N-glycosyl bond and the correct nucleotide is restored through subsequent base excision repair. In addition to excising threatening lesions, DNA glycosylases contribute to epigenetic regulation by mediating DNA demethylation and perform other important functions. However, the catalytic mechanism remains poorly defined for many glycosylases, including MBD4 (methyl-CpG binding domain IV), a member of the helix-hairpin-helix (HhH) superfamily. MBD4 excises thymine from G·T mispairs, suppressing mutations caused by deamination of 5-methylcytosine, and it removes uracil and modified uracils (e.g., 5-hydroxymethyluracil) mispaired with guanine. To investigate the mechanism of MBD4 we solved high-resolution structures of enzyme-DNA complexes at three stages of catalysis. Using a non-cleavable substrate analog, 2'-deoxy-pseudouridine, we determined the first structure of an enzyme-substrate complex for wild-type MBD4, which confirms interactions that mediate lesion recognition and suggests that a catalytic Asp, highly conserved in HhH enzymes, binds the putative nucleophilic water molecule and stabilizes the transition state. Observation that mutating the Asp (to Gly) reduces activity by 2700-fold indicates an important role in catalysis, but probably not one as the nucleophile in a double-displacement reaction, as previously suggested. Consistent with direct-displacement hydrolysis, a structure of the enzyme-product complex indicates a reaction leading to inversion of configuration. A structure with DNA containing 1-azadeoxyribose models a potential oxacarbenium-ion intermediate and suggests the Asp could facilitate migration of the electrophile towards the nucleophilic water. Finally, the structures provide detailed snapshots of the HhH motif, informing how these ubiquitous metal-binding elements mediate DNA binding.
Collapse
Affiliation(s)
- Lakshmi S Pidugu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hilary Bright
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Wen-Jen Lin
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA
| | - Chandrima Majumdar
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA
| | | | - Sheila S David
- Department of Chemistry, University of California Davis, Davis, CA 95616, USA
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Center for Biomolecular Therapeutics, Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA.
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| |
Collapse
|
11
|
Deshpande SSS, Nemani H, Balasinor NH. High fat diet-induced- and genetically inherited- obesity differential alters DNA demethylation pathways in the germline of adult male rats. Reprod Biol 2021; 21:100532. [PMID: 34246869 DOI: 10.1016/j.repbio.2021.100532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/11/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
Obesity is a multifactorial condition with predominantly genetic and environmental causes and is an emerging risk factor for male infertility/subfertility. Epigenetic mechanisms are vulnerable to genetic and environmental changes. Our earlier studies have shown differential effects of genetically inherited (GIO) - and diet-induced- obesity (DIO) on DNA methylation in male germline. Contrary to DNA methylation is DNA demethylation, which also regulates the gene expression by activating transcription. The present study aimed to delineate the effects of obesity on the DNA demethylation pathway using two rat models: GIO (WNIN/Ob) and DIO (high-fat diet). We observed differential alterations in enzymes involved in DNA demethylation by oxidation (Tet1-3) pathway in testis in both groups. An increase in Tets in DIO group and a decrease in GIO group were noted. Analysis of oxidation pathway intermediates (5-hmC, 5-fC, and 5-caC) did not show any effect on testis in DIO group but an increase in 5-hmC and decrease in 5-caC levels in GIO group was observed. Analysis of transcript levels of enzymes related to deamination pathway in testis showed an increase (Gadd45a, Aicda, and Tdg) in DIO group and a decrease (Gadd45a, Aicda, and Tdg) in GIO group. Also, 5-hmC levels were differentially altered in the spermatozoa of both groups without any changes in Tet enzyme levels. These findings highlight differences in effects of GIO and DIO on DNA demethylation mechanisms in male germline, which could be due to differences in endocrine and metabolic profile as well as white fat distribution observed earlier in two groups.
Collapse
Affiliation(s)
- Sharvari S S Deshpande
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive Health, Jehangir Merwanji Street, Parel, Mumbai, 400012, India
| | - Harishankar Nemani
- National Institute of Nutrition Animal Facility, ICMR-National Institute of Nutrition, Jamai-Osmania PO, Hyderabad, 500 007, India
| | - Nafisa H Balasinor
- Department of Neuroendocrinology, ICMR-National Institute for Research in Reproductive Health, Jehangir Merwanji Street, Parel, Mumbai, 400012, India.
| |
Collapse
|
12
|
DNA glycosylases for 8-oxoguanine repair in Staphylococcus aureus. DNA Repair (Amst) 2021; 105:103160. [PMID: 34192601 DOI: 10.1016/j.dnarep.2021.103160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/20/2022]
Abstract
GO system is part of base excision DNA repair and is required for the correct repair of 8-oxoguanine (8-oxoG), one of the most abundant oxidative lesions. Due to the ability of 8-oxoG to mispair with A, this base is highly mutagenic, and its repair requires two enzymes: Fpg that removes 8-oxoG from 8-oxoG:C pairs, and MutY that excises the normal A from 8-oxoG:A mispairs. Here we characterize the properties of putative GO system DNA glycosylases from Staphylococcus aureus, an important human opportunistic pathogen that causes hospital infections and presents a serious health concern due to quick spread of antibiotic-resistant strains. In addition to Fpg and MutY from the reference NCTC 8325 strain (SauFpg1 and SauMutY), we have also studied an Fpg homolog from a multidrug-resistant C0673 isolate (SauFpg2), which is different from SauFpg1 in its sequence. Both SauFpg enzymes showed the highest activity at pH 7.0-9.0 and NaCl concentrations 25-75 mM (SauFpg1) or 50-100 mM (SauFpg2), whereas SauMutY was active at a broad pH range and had a salt optimum at ∼75 mM NaCl. Both SauFpg1 and SauFpg2 bound and cleaved duplexes containing 8-oxoG, 5-hydroxyuracil, 5,6-dihydrouracil or apurinic/apyrimidinic site paired with C, T, or G, but not with A. For SauFpg1 and SauFpg2, 8-oxoG was the best substrate tested, and 5,6-dihydrouracil was the worst one. SauMutY efficiently excised adenine from duplex substrates containing A:8-oxoG or A:G pairs. SauFpg enzymes were readily trapped on DNA by NaBH4 treatment, indicating formation of a Schiff base reaction intermediate. Surprisingly, SauMutY was also trapped significantly better than its E. coli homolog. All three S. aureus GO glycosylases drastically reduced spontaneous mutagenesis when expressed in an fpg mutY E. coli double mutant. Overall, we conclude that S. aureus possesses an active GO system, which could possibly be targeted for sensitization of this pathogen to oxidative stress.
Collapse
|
13
|
Moyon S, Frawley R, Marechal D, Huang D, Marshall-Phelps KLH, Kegel L, Bøstrand SMK, Sadowski B, Jiang YH, Lyons DA, Möbius W, Casaccia P. TET1-mediated DNA hydroxymethylation regulates adult remyelination in mice. Nat Commun 2021; 12:3359. [PMID: 34099715 PMCID: PMC8185117 DOI: 10.1038/s41467-021-23735-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/10/2021] [Indexed: 12/17/2022] Open
Abstract
The mechanisms regulating myelin repair in the adult central nervous system (CNS) are unclear. Here, we identify DNA hydroxymethylation, catalyzed by the Ten-Eleven-Translocation (TET) enzyme TET1, as necessary for myelin repair in young adults and defective in old mice. Constitutive and inducible oligodendrocyte lineage-specific ablation of Tet1 (but not of Tet2), recapitulate this age-related decline in repair of demyelinated lesions. DNA hydroxymethylation and transcriptomic analyses identify TET1-target in adult oligodendrocytes, as genes regulating neuro-glial communication, including the solute carrier (Slc) gene family. Among them, we show that the expression levels of the Na+/K+/Cl- transporter, SLC12A2, are higher in Tet1 overexpressing cells and lower in old or Tet1 knockout. Both aged mice and Tet1 mutants also present inefficient myelin repair and axo-myelinic swellings. Zebrafish mutants for slc12a2b also display swellings of CNS myelinated axons. Our findings suggest that TET1 is required for adult myelin repair and regulation of the axon-myelin interface.
Collapse
Affiliation(s)
- Sarah Moyon
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA.
| | - Rebecca Frawley
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | - Damien Marechal
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | - Dennis Huang
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA
| | | | - Linde Kegel
- Centre for Discovery Brain Sciences, Edinburgh, UK
| | | | - Boguslawa Sadowski
- Department of Neurogenetics, Göttingen, Germany
- Electron Microscopy Core Unit, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Yong-Hui Jiang
- Department of Neurobiology and Pediatrics, Duke University School of Medicine, Durham, NC, USA
| | | | - Wiebke Möbius
- Department of Neurogenetics, Göttingen, Germany
- Electron Microscopy Core Unit, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Patrizia Casaccia
- Neuroscience Initiative Advanced Science Research Center, New York, NY, USA.
- Program of Biology and Biochemistry, The Graduate Center of The City University of New York, New York, NY, USA.
| |
Collapse
|
14
|
Pegoraro M, Weedall GD. Malaria in the 'Omics Era'. Genes (Basel) 2021; 12:genes12060843. [PMID: 34070769 PMCID: PMC8228830 DOI: 10.3390/genes12060843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 12/26/2022] Open
Abstract
Genomics has revolutionised the study of the biology of parasitic diseases. The first Eukaryotic parasite to have its genome sequenced was the malaria parasite Plasmodium falciparum. Since then, Plasmodium genomics has continued to lead the way in the study of the genome biology of parasites, both in breadth—the number of Plasmodium species’ genomes sequenced—and in depth—massive-scale genome re-sequencing of several key species. Here, we review some of the insights into the biology, evolution and population genetics of Plasmodium gained from genome sequencing, and look at potential new avenues in the future genome-scale study of its biology.
Collapse
|
15
|
Insights into the substrate discrimination mechanisms of methyl-CpG-binding domain 4. Biochem J 2021; 478:1985-1997. [PMID: 33960375 DOI: 10.1042/bcj20210017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022]
Abstract
G:T mismatches, the major mispairs generated during DNA metabolism, are repaired in part by mismatch-specific DNA glycosylases such as methyl-CpG-binding domain 4 (MBD4) and thymine DNA glycosylase (TDG). Mismatch-specific DNA glycosylases must discriminate the mismatches against million-fold excess correct base pairs. MBD4 efficiently removes thymine opposite guanine but not opposite adenine. Previous studies have revealed that the substrate thymine is flipped out and enters the catalytic site of the enzyme, while the estranged guanine is stabilized by Arg468 of MBD4. To gain further insights into the mismatch discrimination mechanism of MBD4, we assessed the glycosylase activity of MBD4 toward various base pairs. In addition, we determined a crystal structure of MBD4 bound to T:O6-methylguanine-containing DNA, which suggests the O6 and N2 of purine and the O4 of pyrimidine are required to be a substrate for MBD4. To understand the role of the Arg468 finger in catalysis, we evaluated the glycosylase activity of MBD4 mutants, which revealed the guanidinium moiety of Arg468 may play an important role in catalysis. D560N/R468K MBD4 bound to T:G mismatched DNA shows that the side chain amine moiety of the Lys stabilizes the flipped-out thymine by a water-mediated phosphate pinching, while the backbone carbonyl oxygen of the Lys engages in hydrogen bonds with N2 of the estranged guanine. Comparison of various DNA glycosylase structures implies the guanidinium and amine moieties of Arg and Lys, respectively, may involve in discriminating between substrate mismatches and nonsubstrate base pairs.
Collapse
|
16
|
Yang J, Horton JR, Akdemir KC, Li J, Huang Y, Kumar J, Blumenthal RM, Zhang X, Cheng X. Preferential CEBP binding to T:G mismatches and increased C-to-T human somatic mutations. Nucleic Acids Res 2021; 49:5084-5094. [PMID: 33877329 PMCID: PMC8136768 DOI: 10.1093/nar/gkab276] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
DNA cytosine methylation in mammals modulates gene expression and chromatin accessibility. It also impacts mutation rates, via spontaneous oxidative deamination of 5-methylcytosine (5mC) to thymine. In most cases the resulting T:G mismatches are repaired, following T excision by one of the thymine DNA glycosylases, TDG or MBD4. We found that C-to-T mutations are enriched in the binding sites of CCAAT/enhancer binding proteins (CEBP). Within a CEBP site, the presence of a T:G mismatch increased CEBPβ binding affinity by a factor of >60 relative to the normal C:G base pair. This enhanced binding to a mismatch inhibits its repair by both TDG and MBD4 in vitro. Furthermore, repair of the deamination product of unmethylated cytosine, which yields a U:G DNA mismatch that is normally repaired via uracil DNA glycosylase, is also inhibited by CEBPβ binding. Passage of a replication fork over either a T:G or U:G mismatch, before repair can occur, results in a C-to-T mutation in one of the daughter duplexes. Our study thus provides a plausible mechanism for accumulation of C-to-T human somatic mutations.
Collapse
Affiliation(s)
- Jie Yang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John R Horton
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kadir C Akdemir
- Departments of Genomic Medicine and Neurosurgery, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jia Li
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics & Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Janani Kumar
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Xing Zhang
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| |
Collapse
|
17
|
Alekseeva IV, Bakman AS, Iakovlev DA, Kuznetsov NA, Fedorova OS. Comparative Analysis of the Activity of the Polymorphic Variants of Human Uracil-DNA-Glycosylases SMUG1 and MBD4. Mol Biol 2021. [DOI: 10.1134/s0026893321020035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
18
|
Westwood MN, Ljunggren KD, Boyd B, Becker J, Dwyer TJ, Meints GA. Single-Base Lesions and Mismatches Alter the Backbone Conformational Dynamics in DNA. Biochemistry 2021; 60:873-885. [PMID: 33689312 DOI: 10.1021/acs.biochem.0c00784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
DNA damage has been implicated in numerous human diseases, particularly cancer, and the aging process. Single-base lesions and mismatches in DNA can be cytotoxic or mutagenic and are recognized by a DNA glycosylase during the process of base excision repair. Altered local dynamics and conformational properties in damaged DNAs have previously been suggested to assist in recognition and specificity. Herein, we use solution nuclear magnetic resonance to quantify changes in BI-BII backbone conformational dynamics due to the presence of single-base lesions in DNA, including uracil, dihydrouracil, 1,N6-ethenoadenine, and T:G mismatches. Stepwise changes to the %BII and ΔG of the BI-BII dynamic equilibrium compared to those of unmodified sequences were observed. Additionally, the equilibrium skews toward endothermicity for the phosphates nearest the lesion/mismatched base pair. Finally, the phosphates with the greatest alterations correlate with those most relevant to the repair of enzyme binding. All of these results suggest local conformational rearrangement of the DNA backbone may play a role in lesion recognition by repair enzymes.
Collapse
Affiliation(s)
- M N Westwood
- Department of Chemistry, Missouri State University, 901 South National Avenue, Springfield, Missouri 65897, United States
| | - K D Ljunggren
- Department of Chemistry, Missouri State University, 901 South National Avenue, Springfield, Missouri 65897, United States
| | - Benjamin Boyd
- Department of Chemistry, Missouri State University, 901 South National Avenue, Springfield, Missouri 65897, United States
| | - Jaclyn Becker
- Department of Chemistry, Missouri State University, 901 South National Avenue, Springfield, Missouri 65897, United States
| | - Tammy J Dwyer
- Department of Chemistry and Biochemistry, University of San Diego, San Diego, California 92110, United States
| | - Gary A Meints
- Department of Chemistry, Missouri State University, 901 South National Avenue, Springfield, Missouri 65897, United States
| |
Collapse
|
19
|
Hewitt G, Borel V, Segura-Bayona S, Takaki T, Ruis P, Bellelli R, Lehmann LC, Sommerova L, Vancevska A, Tomas-Loba A, Zhu K, Cooper C, Fugger K, Patel H, Goldstone R, Schneider-Luftman D, Herbert E, Stamp G, Brough R, Pettitt S, Lord CJ, West SC, Ahel I, Ahel D, Chapman JR, Deindl S, Boulton SJ. Defective ALC1 nucleosome remodeling confers PARPi sensitization and synthetic lethality with HRD. Mol Cell 2021; 81:767-783.e11. [PMID: 33333017 PMCID: PMC7895907 DOI: 10.1016/j.molcel.2020.12.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/09/2020] [Accepted: 12/03/2020] [Indexed: 12/19/2022]
Abstract
Chromatin is a barrier to efficient DNA repair, as it hinders access and processing of certain DNA lesions. ALC1/CHD1L is a nucleosome-remodeling enzyme that responds to DNA damage, but its precise function in DNA repair remains unknown. Here we report that loss of ALC1 confers sensitivity to PARP inhibitors, methyl-methanesulfonate, and uracil misincorporation, which reflects the need to remodel nucleosomes following base excision by DNA glycosylases but prior to handover to APEX1. Using CRISPR screens, we establish that ALC1 loss is synthetic lethal with homologous recombination deficiency (HRD), which we attribute to chromosome instability caused by unrepaired DNA gaps at replication forks. In the absence of ALC1 or APEX1, incomplete processing of BER intermediates results in post-replicative DNA gaps and a critical dependence on HR for repair. Hence, targeting ALC1 alone or as a PARP inhibitor sensitizer could be employed to augment existing therapeutic strategies for HRD cancers.
Collapse
Affiliation(s)
- Graeme Hewitt
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Valerie Borel
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Tohru Takaki
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Phil Ruis
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Laura C Lehmann
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden
| | - Lucia Sommerova
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | | | - Antonia Tomas-Loba
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Kang Zhu
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - Christopher Cooper
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - Kasper Fugger
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Harshil Patel
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | | | - Ellie Herbert
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Gordon Stamp
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Rachel Brough
- The CRUK Gene Function Laboratory, The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London SW3 6JB, UK
| | - Stephen Pettitt
- The CRUK Gene Function Laboratory, The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London SW3 6JB, UK
| | - Christopher J Lord
- The CRUK Gene Function Laboratory, The Breast Cancer Now Toby Robins Research Centre, The Institute of Cancer Research, London SW3 6JB, UK
| | - Stephen C West
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Ivan Ahel
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - Dragana Ahel
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - J Ross Chapman
- Medical Research Council (MRC) Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Sebastian Deindl
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, 75124 Uppsala, Sweden
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Artios Pharma Ltd., Meditrina, Babraham Research Campus, Cambridge CB22 3AT, UK.
| |
Collapse
|
20
|
Iakovlev DA, Alekseeva IV, Kuznetsov NA, Fedorova OS. Role of Arg243 and His239 Residues in the Recognition of Damaged Nucleotides by Human Uracil-DNA Glycosylase SMUG1. BIOCHEMISTRY (MOSCOW) 2021; 85:594-603. [PMID: 32571189 DOI: 10.1134/s0006297920050089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Human uracil-DNA glycosylase SMUG1 removes uracil residues and some other noncanonical or damaged bases from DNA. Despite the functional importance of this enzyme, its X-ray structure is still unavailable. Previously, we performed homology modeling of human SMUG1 structure and suggested the roles of some amino acid residues in the recognition of damaged nucleotides and their removal from DNA. In this study, we investigated the kinetics of conformational transitions in the protein and in various DNA substrates during enzymatic catalysis using the stopped-flow method based on changes in the fluorescence intensity of enzyme's tryptophan residues and 2-aminopurine in DNA or fluorescence resonance energy transfer (FRET) between fluorophores in DNA. The kinetic mechanism of interactions between reaction intermediates was identified, and kinetic parameters of the intermediate formation and dissociation were calculated. The obtained data help in elucidating the functions of His239 and Arg243 residues in the recognition and removal of damaged nucleotides by SMUG1.
Collapse
Affiliation(s)
- D A Iakovlev
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.,Novosibirsk State University, Department of Natural Sciences, Novosibirsk, 630090, Russia
| | - I V Alekseeva
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - N A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
| | - O S Fedorova
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
| |
Collapse
|
21
|
Catalytic mechanism of the mismatch-specific DNA glycosylase methyl-CpG-binding domain 4. Biochem J 2020; 477:1601-1612. [PMID: 32297632 DOI: 10.1042/bcj20200125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/09/2020] [Accepted: 04/14/2020] [Indexed: 12/15/2022]
Abstract
Thymine:guanine base pairs are major promutagenic mismatches occurring in DNA metabolism. If left unrepaired, these mispairs can cause C to T transition mutations. In humans, T:G mismatches are repaired in part by mismatch-specific DNA glycosylases such as methyl-CpG-binding domain 4 (hMBD4) and thymine-DNA glycosylase. Unlike lesion-specific DNA glycosylases, T:G-mismatch-specific DNA glycosylases specifically recognize both bases of the mismatch and remove the thymine but only from mispairs with guanine. Despite the advances in biochemical and structural characterizations of hMBD4, the catalytic mechanism of hMBD4 remains elusive. Herein, we report two structures of hMBD4 processing T:G-mismatched DNA. A high-resolution crystal structure of Asp560Asn hMBD4-T:G complex suggests that hMBD4-mediated glycosidic bond cleavage occurs via a general base catalysis mechanism assisted by Asp560. A structure of wild-type hMBD4 encountering T:G-containing DNA shows the generation of an apurinic/apyrimidinic (AP) site bearing the C1'-(S)-OH. The inversion of the stereochemistry at the C1' of the AP-site indicates that a nucleophilic water molecule approaches from the back of the thymine substrate, suggesting a bimolecular displacement mechanism (SN2) for hMBD4-catalyzed thymine excision. The AP-site is stabilized by an extensive hydrogen bond network in the MBD4 catalytic site, highlighting the role of MBD4 in protecting the genotoxic AP-site.
Collapse
|
22
|
Tran A, Zheng S, White DS, Curry AM, Cen Y. Retracted Article: Divergent synthesis of 5-substituted pyrimidine 2'-deoxynucleosides and their incorporation into oligodeoxynucleotides for the survey of uracil DNA glycosylases. Chem Sci 2020; 11:11818-11826. [PMID: 34123208 PMCID: PMC8162711 DOI: 10.1039/d0sc04161k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/07/2020] [Indexed: 11/21/2022] Open
Abstract
Recent studies have indicated that 5-methylcytosine (5mC) residues in DNA can be oxidized and potentially deaminated to the corresponding thymine analogs. Some of these oxidative DNA damages have been implicated as new epigenetic markers that could have profound influences on chromatin function as well as disease pathology. In response to oxidative damage, the cells have a complex network of repair systems that recognize, remove and rebuild the lesions. However, how the modified nucleobases are detected and repaired remains elusive, largely due to the limited availability of synthetic oligodeoxynucleotides (ODNs) containing these novel DNA modifications. A concise and divergent synthetic strategy to 5mC derivatives has been developed. These derivatives were further elaborated to the corresponding phosphoramidites to enable the site-specific incorporation of modified nucleobases into ODNs using standard solid-phase DNA synthesis. The synthetic methodology, along with the panel of ODNs, is of great value to investigate the biological functions of epigenetically important nucleobases, and to elucidate the diversity in chemical lesion repair.
Collapse
Affiliation(s)
- Ai Tran
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences Colchester VT 05446 USA
| | - Song Zheng
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences Colchester VT 05446 USA
| | - Dawanna S White
- Department of Medicinal Chemistry, Virginia Commonwealth University Richmond VA 23219 USA +1-804-828-7405
| | - Alyson M Curry
- Department of Medicinal Chemistry, Virginia Commonwealth University Richmond VA 23219 USA +1-804-828-7405
| | - Yana Cen
- Department of Medicinal Chemistry, Virginia Commonwealth University Richmond VA 23219 USA +1-804-828-7405
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University Richmond VA 23219 USA
| |
Collapse
|
23
|
Arthur-Farraj P, Moyon S. DNA methylation in Schwann cells and in oligodendrocytes. Glia 2020; 68:1568-1583. [PMID: 31958184 DOI: 10.1002/glia.23784] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/17/2019] [Accepted: 01/10/2020] [Indexed: 12/12/2022]
Abstract
DNA methylation is one of many epigenetic marks, which directly modifies base residues, usually cytosines, in a multiple-step cycle. It has been linked to the regulation of gene expression and alternative splicing in several cell types, including during cell lineage specification and differentiation processes. DNA methylation changes have also been observed during aging, and aberrant methylation patterns have been reported in several neurological diseases. We here review the role of DNA methylation in Schwann cells and oligodendrocytes, the myelin-forming glia of the peripheral and central nervous systems, respectively. We first address how methylation and demethylation are regulating myelinating cells' differentiation during development and repair. We then mention how DNA methylation dysregulation in diseases and cancers could explain their pathogenesis by directly influencing myelinating cells' proliferation and differentiation capacities.
Collapse
Affiliation(s)
- Peter Arthur-Farraj
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Sarah Moyon
- Neuroscience Initiative Advanced Science Research Center, CUNY, New York, New York
| |
Collapse
|
24
|
Kuznetsov NA, Fedorova OS. Kinetic Milestones of Damage Recognition by DNA Glycosylases of the Helix-Hairpin-Helix Structural Superfamily. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1241:1-18. [DOI: 10.1007/978-3-030-41283-8_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
25
|
Koliadenko V, Wilanowski T. Additional functions of selected proteins involved in DNA repair. Free Radic Biol Med 2020; 146:1-15. [PMID: 31639437 DOI: 10.1016/j.freeradbiomed.2019.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022]
Abstract
Protein moonlighting is a phenomenon in which a single polypeptide chain can perform a number of different unrelated functions. Here we present our analysis of moonlighting in the case of selected DNA repair proteins which include G:T mismatch-specific thymine DNA glycosylase (TDG), methyl-CpG-binding domain protein 4 (MBD4), apurinic/apyrimidinic endonuclease 1 (APE1), AlkB homologs, poly (ADP-ribose) polymerase 1 (PARP-1) and single-strand selective monofunctional uracil DNA glycosylase 1 (SMUG1). Most of their additional functions are not accidental and clear patterns are emerging. Participation in RNA metabolism is not surprising as bases occurring in RNA are the same or very similar to those in DNA. Other common additional function involves regulation of transcription. This is not unexpected as these proteins bind to specific DNA regions for DNA repair, hence they can also be recruited to regulate transcription. Participation in demethylation and replication of DNA appears logical as well. Some of the multifunctional DNA repair proteins play major roles in many diseases, including cancer. However, their moonlighting might prove a major difficulty in the development of new therapies because it will not be trivial to target a single protein function without affecting its other functions that are not related to the disease.
Collapse
Affiliation(s)
- Vlada Koliadenko
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Tomasz Wilanowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland.
| |
Collapse
|
26
|
Fang Y, Zou P. Genome-Wide Mapping of Oxidative DNA Damage via Engineering of 8-Oxoguanine DNA Glycosylase. Biochemistry 2019; 59:85-89. [PMID: 31618020 DOI: 10.1021/acs.biochem.9b00782] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The occurrence of 8-oxo-7,8-dihydroguanine (OG) in the genome, as one of the major DNA oxidative damages, has been implicated in an array of biological processes, ranging from mutagenesis to transcriptional regulation. Genome-wide mapping of oxidative damages could shed light on the underlying cellular mechanism. In the present study, we engineered the hOGG1 enzyme, a primary 8-oxoguanine DNA glycosylase, into a guanine oxidation-profiling tool. Our method, called enTRAP-seq, successfully identified more than 1400 guanine oxidation sites in the mouse embryonic fibroblast genome. These OG peaks were enriched in open chromatin regions and regulatory elements, including promoters, 5' untranslated regions, and CpG islands. Collectively, we present a simple and generalizable approach for the genome-wide profiling of DNA damages with high sensitivity and specificity.
Collapse
Affiliation(s)
- Yuxin Fang
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education , Peking University , Beijing 100871 , China
| | - Peng Zou
- College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education , Peking University , Beijing 100871 , China.,Peking-Tsinghua Center for Life Sciences , Peking University , Beijing 100871 , China.,PKU-IDG/McGovern Institute for Brain Research , Peking University , Beijing 100871 , China
| |
Collapse
|
27
|
Iakovlev DA, Alekseeva IV, Vorobjev YN, Kuznetsov NA, Fedorova OS. The Role of Active-Site Residues Phe98, His239, and Arg243 in DNA Binding and in the Catalysis of Human Uracil-DNA Glycosylase SMUG1. Molecules 2019; 24:molecules24173133. [PMID: 31466351 PMCID: PMC6749576 DOI: 10.3390/molecules24173133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 11/16/2022] Open
Abstract
Human SMUG1 (hSMUG1) hydrolyzes the N-glycosidic bond of uracil and some uracil lesions formed in the course of epigenetic regulation. Despite the functional importance of hSMUG1 in the DNA repair pathway, the damage recognition mechanism has been elusive to date. In the present study, our objective was to build a model structure of the enzyme-DNA complex of wild-type hSMUG1 and several hSMUG1 mutants containing substitution F98W, H239A, or R243A. Enzymatic activity of these mutant enzymes was examined by polyacrylamide gel electrophoresis analysis of the reaction product formation and pre-steady-state analysis of DNA conformational changes during enzyme-DNA complex formation. It was shown that substitutions F98W and H239A disrupt specific contacts generated by the respective wild-type residues, namely stacking with a flipped out Ura base in the damaged base-binding pocket or electrostatic interactions with DNA in cases of Phe98 and His239, respectively. A loss of the Arg side chain in the case of R243A reduced the rate of DNA bending and increased the enzyme turnover rate, indicating facilitation of the product release step.
Collapse
Affiliation(s)
- Danila A Iakovlev
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia
| | - Irina V Alekseeva
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia
| | - Yury N Vorobjev
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia.
- Department of Natural Sciences, Novosibirsk State University (NSU), 2 Pirogova St., Novosibirsk 630090, Russia.
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia.
- Department of Natural Sciences, Novosibirsk State University (NSU), 2 Pirogova St., Novosibirsk 630090, Russia.
| |
Collapse
|
28
|
Boldinova EO, Khairullin RF, Makarova AV, Zharkov DO. Isoforms of Base Excision Repair Enzymes Produced by Alternative Splicing. Int J Mol Sci 2019; 20:ijms20133279. [PMID: 31277343 PMCID: PMC6651865 DOI: 10.3390/ijms20133279] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 06/29/2019] [Accepted: 07/02/2019] [Indexed: 02/07/2023] Open
Abstract
Transcripts of many enzymes involved in base excision repair (BER) undergo extensive alternative splicing, but functions of the corresponding alternative splice variants remain largely unexplored. In this review, we cover the studies describing the common alternatively spliced isoforms and disease-associated variants of DNA glycosylases, AP-endonuclease 1, and DNA polymerase beta. We also discuss the roles of alternative splicing in the regulation of their expression, catalytic activities, and intracellular transport.
Collapse
Affiliation(s)
| | - Rafil F Khairullin
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 9 Parizhskoy Kommuny Str., 420012 Kazan, Russia
| | - Alena V Makarova
- RAS Institute of Molecular Genetics, 2 Kurchatova Sq., 123182 Moscow, Russia.
| | - Dmitry O Zharkov
- Novosibirsk State University, 1 Pirogova St., 630090 Novosibirsk, Russia.
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia.
| |
Collapse
|
29
|
D'Addario C, Bellia F, Benatti B, Grancini B, Vismara M, Pucci M, De Carlo V, Viganò C, Galimberti D, Fenoglio C, Scarpini E, Maccarrone M, Dell'Osso B. Exploring the role of BDNF DNA methylation and hydroxymethylation in patients with obsessive compulsive disorder. J Psychiatr Res 2019; 114:17-23. [PMID: 31004918 DOI: 10.1016/j.jpsychires.2019.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/20/2019] [Accepted: 04/05/2019] [Indexed: 01/12/2023]
Abstract
Obsessive-compulsive disorder (OCD) is a clinically heterogeneous neuropsychiatric condition associated with profound disability, whose susceptibility, stemming from genetic and environmental factors that intersect with each other, is still under investigation. In this perspective, we sought to explore the transcriptional regulation of Brain Derived Neurotrophic Factor (BDNF), a promising candidate biomarker in both development and etiology of different neuropsychiatric conditions, in peripheral blood mononuclear cells from OCD patients and healthy controls. In particular, we focused on BDNF gene expression and interrogated in depth DNA methylation and hydroxymethylation at gene promoters (exons I, IV and IX) in a sample of OCD patients attending a tertiary OCD Clinic to receive guidelines-recommended treatment, and matched controls. Our preliminary data showed a significant increase in BDNF gene expression and a significant correlation with changes in the two epigenetic modifications selectively at promoter exon I, with no changes in the other promoters under study. We can conclude that transcriptional regulation of BDNF in OCD engages epigenetic mechanisms, and can suggest that this is likely evoked by the long-term pharmacotherapy. It is important to underline that many different factors need to be taken into account (i.e. age, sex, duration of illness, treatment), and thus further studies are mandatory to investigate their role in the epigenetic regulation of BDNF gene. Of note, we provide unprecedented evidence for the importance of analyzing 5-hydroxymethylcytosine levels to correctly evaluate 5-methylcytosine changes.
Collapse
Affiliation(s)
- Claudio D'Addario
- University of Teramo, Bioscience, Teramo, Italy; Karolinska Institutet, Department of Clinical Neuroscience, Stockholm, Sweden.
| | | | - Beatrice Benatti
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy
| | - Benedetta Grancini
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy
| | - Matteo Vismara
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy
| | | | - Vera De Carlo
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy
| | - Caterina Viganò
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy
| | - Daniela Galimberti
- University of Milan, Dino Ferrari Center, Milan, Italy; Fondazione IRCCS Ca' Granda, Ospedale Policlinico, Neurodegenerative Diseases Unit, Milan, Italy
| | - Chiara Fenoglio
- University of Milan, Dino Ferrari Center, Milan, Italy; Fondazione IRCCS Ca' Granda, Ospedale Policlinico, Neurodegenerative Diseases Unit, Milan, Italy
| | - Elio Scarpini
- University of Milan, Dino Ferrari Center, Milan, Italy; Fondazione IRCCS Ca' Granda, Ospedale Policlinico, Neurodegenerative Diseases Unit, Milan, Italy
| | - Mauro Maccarrone
- Department of Medicine, Campus Bio-Medico University of Rome, Rome, Italy; Fondazione IRCCS Santa Lucia, Unit of Lipid Neurochemistry, Rome, Italy
| | - Bernardo Dell'Osso
- University of Milan, Department of Biomedical and Clinical Sciences Luigi Sacco, Milano, Italy; CRC "Aldo Ravelli", University of Milan, Milano, Italy; Department of Psychiatry and Behavioral Sciences, Stanford University, CA, USA.
| |
Collapse
|
30
|
Ahn WC, Aroli S, Kim JH, Moon JH, Lee GS, Lee MH, Sang PB, Oh BH, Varshney U, Woo EJ. Covalent binding of uracil DNA glycosylase UdgX to abasic DNA upon uracil excision. Nat Chem Biol 2019; 15:607-614. [PMID: 31101917 DOI: 10.1038/s41589-019-0289-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 04/10/2019] [Indexed: 11/09/2022]
Abstract
Uracil DNA glycosylases (UDGs) are important DNA repair enzymes that excise uracil from DNA, yielding an abasic site. Recently, UdgX, an unconventional UDG with extremely tight binding to DNA containing uracil, was discovered. The structure of UdgX from Mycobacterium smegmatis in complex with DNA shows an overall similarity to that of family 4 UDGs except for a protruding loop at the entrance of the uracil-binding pocket. Surprisingly, H109 in the loop was found to make a covalent bond to the abasic site to form a stable intermediate, while the excised uracil remained in the pocket of the active site. H109 functions as a nucleophile to attack the oxocarbenium ion, substituting for the catalytic water molecule found in other UDGs. To our knowledge, this change from a catalytic water attack to a direct nucleophilic attack by the histidine residue is unprecedented. UdgX utilizes a unique mechanism of protecting cytotoxic abasic sites from exposure to the cellular environment.
Collapse
Affiliation(s)
- Woo-Chan Ahn
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea.,Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Shashanka Aroli
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Jin-Hahn Kim
- Creative Research Initiative Center for Chemical Dynamics in Living Cells, Department of Chemistry, Chung-Ang University, Seoul, Korea
| | - Jeong Hee Moon
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Ga Seal Lee
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Min-Ho Lee
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Pau Biak Sang
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Byung-Ha Oh
- Department of Biological Sciences, KAIST Institute for the Biocentury, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
| | - Eui-Jeon Woo
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea. .,University of Science and Technology, Daejeon, Republic of Korea.
| |
Collapse
|
31
|
Tu J, Chen R, Yang Y, Cao W, Xie W. Suicide inactivation of the uracil DNA glycosylase UdgX by covalent complex formation. Nat Chem Biol 2019; 15:615-622. [PMID: 31101915 DOI: 10.1038/s41589-019-0290-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/10/2019] [Indexed: 01/08/2023]
Abstract
A uracil DNA glycosylase (UDG) from Mycobacterium smegmatis (MsmUdgX) shares sequence similarity with family 4 UDGs and forms exceedingly stable complexes with single-stranded uracil-containing DNAs (ssDNA-Us) that are resistant to denaturants. However, MsmUdgX has been reported to be inactive in excising uracil from ssDNA-Us and the underlying structural basis is unclear. Here, we report high-resolution crystal structures of MsmUdgX in the free, uracil- and DNA-bound forms, respectively. The structural information, supported by mutational and biochemical analyses, indicates that the conserved residue His109 located on a characteristic loop forms an irreversible covalent linkage with the deoxyribose at the apyrimidinic site of ssDNA-U, thus rendering the enzyme unable to regenerate. By proposing the catalytic pathway and molecular mechanism for MsmUdgX, our studies provide an insight into family 4 UDGs and UDGs in general.
Collapse
Affiliation(s)
- Jie Tu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Ran Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Ye Yang
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Weiguo Cao
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Wei Xie
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou, Guangdong, China.
| |
Collapse
|
32
|
Geyer KK, Munshi SE, Whiteland HL, Fernandez-Fuentes N, Phillips DW, Hoffmann KF. Methyl-CpG-binding (SmMBD2/3) and chromobox (SmCBX) proteins are required for neoblast proliferation and oviposition in the parasitic blood fluke Schistosoma mansoni. PLoS Pathog 2018; 14:e1007107. [PMID: 29953544 PMCID: PMC6023120 DOI: 10.1371/journal.ppat.1007107] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/17/2018] [Indexed: 12/11/2022] Open
Abstract
While schistosomiasis remains a significant health problem in low to middle income countries, it also represents a recently recognised threat to more economically-developed regions. Until a vaccine is developed, this neglected infectious disease is primarily controlled by praziquantel, a drug with a currently unknown mechanism of action. By further elucidating how Schistosoma molecular components cooperate to regulate parasite developmental processes, next generation targets will be identified. Here, we continue our studies on schistosome epigenetic participants and characterise the function of a DNA methylation reader, the Schistosoma mansoni methyl-CpG-binding domain protein (SmMBD2/3). Firstly, we demonstrate that SmMBD2/3 contains amino acid features essential for 5-methyl cytosine (5mC) binding and illustrate that adult schistosome nuclear extracts (females > males) contain this activity. We subsequently show that SmMBD2/3 translocates into nuclear compartments of transfected murine NIH-3T3 fibroblasts and recombinant SmMBD2/3 exhibits 5mC binding activity. Secondly, using a yeast-two hybrid (Y2H) screen, we show that SmMBD2/3 interacts with the chromo shadow domain (CSD) of an epigenetic adaptor, S. mansoni chromobox protein (SmCBX). Moreover, fluorescent in situ hybridisation (FISH) mediated co-localisation of Smmbd2/3 and Smcbx to mesenchymal cells as well as somatic- and reproductive- stem cells confirms the Y2H results and demonstrates that these interacting partners are ubiquitously expressed and found within both differentiated as well as proliferating cells. Finally, using RNA interference, we reveal that depletion of Smmbd2/3 or Smcbx in adult females leads to significant reductions (46-58%) in the number of proliferating somatic stem cells (PSCs or neoblasts) as well as in the quantity of in vitro laid eggs. Collectively, these results further expand upon the schistosome components involved in epigenetic processes and suggest that pharmacological inhibition of SmMBD2/3 and/or SmCBX biology could prove useful in the development of future schistosomiasis control strategies.
Collapse
Affiliation(s)
- Kathrin K. Geyer
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Sabrina E. Munshi
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Helen L. Whiteland
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Narcis Fernandez-Fuentes
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Dylan W. Phillips
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Karl F. Hoffmann
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| |
Collapse
|
33
|
Uncovering universal rules governing the selectivity of the archetypal DNA glycosylase TDG. Proc Natl Acad Sci U S A 2018; 115:5974-5979. [PMID: 29784784 DOI: 10.1073/pnas.1803323115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Thymine DNA glycosylase (TDG) is a pivotal enzyme with dual roles in both genome maintenance and epigenetic regulation. TDG is involved in cytosine demethylation at CpG sites in DNA. Here we have used molecular modeling to delineate the lesion search and DNA base interrogation mechanisms of TDG. First, we examined the capacity of TDG to interrogate not only DNA substrates with 5-carboxyl cytosine modifications but also G:T mismatches and nonmismatched (A:T) base pairs using classical and accelerated molecular dynamics. To determine the kinetics, we constructed Markov state models. Base interrogation was found to be highly stochastic and proceeded through insertion of an arginine-containing loop into the DNA minor groove to transiently disrupt Watson-Crick pairing. Next, we employed chain-of-replicas path-sampling methodologies to compute minimum free energy paths for TDG base extrusion. We identified the key intermediates imparting selectivity and determined effective free energy profiles for the lesion search and base extrusion into the TDG active site. Our results show that DNA sculpting, dynamic glycosylase interactions, and stabilizing contacts collectively provide a powerful mechanism for the detection and discrimination of modified bases and epigenetic marks in DNA.
Collapse
|
34
|
Epigenetics in teleost fish: From molecular mechanisms to physiological phenotypes. Comp Biochem Physiol B Biochem Mol Biol 2018; 224:210-244. [PMID: 29369794 DOI: 10.1016/j.cbpb.2018.01.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 01/08/2018] [Accepted: 01/16/2018] [Indexed: 02/07/2023]
Abstract
While the field of epigenetics is increasingly recognized to contribute to the emergence of phenotypes in mammalian research models across different developmental and generational timescales, the comparative biology of epigenetics in the large and physiologically diverse vertebrate infraclass of teleost fish remains comparatively understudied. The cypriniform zebrafish and the salmoniform rainbow trout and Atlantic salmon represent two especially important teleost orders, because they offer the unique possibility to comparatively investigate the role of epigenetic regulation in 3R and 4R duplicated genomes. In addition to their sequenced genomes, these teleost species are well-characterized model species for development and physiology, and therefore allow for an investigation of the role of epigenetic modifications in the emergence of physiological phenotypes during an organism's lifespan and in subsequent generations. This review aims firstly to describe the evolution of the repertoire of genes involved in key molecular epigenetic pathways including histone modifications, DNA methylation and microRNAs in zebrafish, rainbow trout, and Atlantic salmon, and secondly, to discuss recent advances in research highlighting a role for molecular epigenetics in shaping physiological phenotypes in these and other teleost models. Finally, by discussing themes and current limitations of the emerging field of teleost epigenetics from both theoretical and technical points of view, we will highlight future research needs and discuss how epigenetics will not only help address basic research questions in comparative teleost physiology, but also inform translational research including aquaculture, aquatic toxicology, and human disease.
Collapse
|
35
|
Garcia-Gomez A, Li T, Kerick M, Català-Moll F, Comet NR, Rodríguez-Ubreva J, de la Rica L, Branco MR, Martín J, Ballestar E. TET2- and TDG-mediated changes are required for the acquisition of distinct histone modifications in divergent terminal differentiation of myeloid cells. Nucleic Acids Res 2017; 45:10002-10017. [PMID: 28973458 PMCID: PMC5622316 DOI: 10.1093/nar/gkx666] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/19/2017] [Indexed: 12/21/2022] Open
Abstract
The plasticity of myeloid cells is illustrated by a diversity of functions including their role as effectors of innate immunity as macrophages (MACs) and bone remodelling as osteoclasts (OCs). TET2, a methylcytosine dioxygenase highly expressed in these cells and frequently mutated in myeloid leukemias, may be a key contributor to this plasticity. Through transcriptomic and epigenomic analyses, we investigated 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) and gene expression changes in two divergent terminal myeloid differentiation processes, namely MAC and OC differentiation. MACs and OCs undergo highly similar 5hmC and 5mC changes, despite their wide differences in gene expression. Many TET2- and thymine-DNA glycosylase (TDG)-dependent 5mC and 5hmC changes directly activate the common terminal myeloid differentiation programme. However, the acquisition of differential features between MACs and OCs also depends on TET2/TDG. In fact, 5mC oxidation precedes differential histone modification changes between MACs and OCs. TET2 and TDG downregulation impairs the acquisition of such differential histone modification and expression patterns at MAC-/OC-specific genes. We prove that the histone H3K4 methyltransferase SETD1A is differentially recruited between MACs and OCs in a TET2-dependent manner. We demonstrate a novel role of these enzymes in the establishment of specific elements of identity and function in terminal myeloid differentiation.
Collapse
Affiliation(s)
- Antonio Garcia-Gomez
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Tianlu Li
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Martin Kerick
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Parque Tecnológico de La Salud (PTS), Granada, Spain
| | - Francesc Català-Moll
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Natalia R Comet
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Javier Rodríguez-Ubreva
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| | - Lorenzo de la Rica
- Barts and The London School of Medicine and Dentistry, Centre for Neuroscience & Trauma, Blizard Institute, 4 Newark Street, London E1 2AT, UK
| | - Miguel R Branco
- Barts and The London School of Medicine and Dentistry, Centre for Neuroscience & Trauma, Blizard Institute, 4 Newark Street, London E1 2AT, UK
| | - Javier Martín
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Parque Tecnológico de La Salud (PTS), Granada, Spain
| | - Esteban Ballestar
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Barcelona, Spain
| |
Collapse
|
36
|
Zhang P, Hastert FD, Ludwig AK, Breitwieser K, Hofstätter M, Cardoso MC. DNA base flipping analytical pipeline. Biol Methods Protoc 2017; 2:bpx010. [PMID: 32161792 PMCID: PMC6994035 DOI: 10.1093/biomethods/bpx010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 06/01/2017] [Accepted: 06/07/2017] [Indexed: 11/20/2022] Open
Abstract
DNA base modifications and mutations are observed in all genomes throughout the kingdoms of life. Proteins involved in their establishment and removal were shown to use a base flipping mechanism to access their substrates. To better understand how proteins flip DNA bases to modify or remove them, we optimized and developed a pipeline of methods to step-by-step detect the process starting with protein–DNA interaction, base flipping itself and the ensuing DNA base modification or excision. As methylcytosine is the best-studied DNA modification, here we focus on the process of writing, modifying and reading this DNA base. Using multicolor electrophoretic mobility shift assays, we show that the methylcytosine modifier Tet1 exhibits little DNA sequence specificity with only a slight preference for methylated CpG containing DNA. A combination of chloroacetaldehyde treatment and high-resolution melting temperature analysis allowed us to detect base flipping induced by the methylcytosine modifier Tet1 as well as the methylcytosine writer M.HpaII. Finally, we show that high-resolution melting temperature analysis can be used to detect the activity of glycosylases, methyltransferases and dioxigenases on DNA substrates. Taken together, this DNA base flipping analytical pipeline (BaFAP) provide a complete toolbox for the fast and sensitive analysis of proteins that bind, flip and modify or excise DNA bases.
Collapse
Affiliation(s)
- Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Germany
| | - Florian D Hastert
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Germany
| | - Anne K Ludwig
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Germany
| | - Kai Breitwieser
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Germany
| | | | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Germany
| |
Collapse
|
37
|
MBD4 Facilitates Immunoglobulin Class Switch Recombination. Mol Cell Biol 2017; 37:MCB.00316-16. [PMID: 27777312 DOI: 10.1128/mcb.00316-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/30/2016] [Indexed: 01/02/2023] Open
Abstract
Immunoglobulin heavy chain class switch recombination (CSR) requires targeted formation of DNA double-strand breaks (DSBs) in repetitive switch region elements followed by ligation between distal breaks. The introduction of DSBs is initiated by activation-induced cytidine deaminase (AID) and requires base excision repair (BER) and mismatch repair (MMR). The BER enzyme methyl-CpG binding domain protein 4 (MBD4) has been linked to the MMR pathway through its interaction with MutL homologue 1 (MLH1). We find that when Mbd4 exons 6 to 8 are deleted in a switching B cell line, DSB formation is severely reduced and CSR frequency is impaired. Impaired CSR can be rescued by ectopic expression of Mbd4 Mbd4 deficiency yields a deficit in DNA end processing similar to that found in MutS homologue 2 (Msh2)- and Mlh1-deficient B cells. We demonstrate that microhomology-rich S-S junctions are enriched in cells in which Mbd4 is deleted. Our studies suggest that Mbd4 is a component of MMR-directed DNA end processing.
Collapse
|
38
|
Tyugashev TE, Kuznetsova AA, Kuznetsov NA, Fedorova OS. Interaction features of adenine DNA glycosylase MutY from E. coli with DNA substrates. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2017. [DOI: 10.1134/s1068162017010101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
39
|
Yakovlev DA, Kuznetsova AA, Fedorova OS, Kuznetsov NA. Search for Modified DNA Sites with the Human Methyl-CpG-Binding Enzyme MBD4. Acta Naturae 2017; 9:88-98. [PMID: 28461979 PMCID: PMC5406665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The MBD4 enzyme initiates the process of DNA demethylation by the excision of modified DNA bases, resulting in the formation of apurinic/apyrimidinic sites. MBD4 contains a methyl-CpG-binding domain which provides the localization of the enzyme at the CpG sites, and a DNA glycosylase domain that is responsible for the catalytic activity. The aim of this work was to clarify the mechanisms of specific site recognition and formation of catalytically active complexes between model DNA substrates and the catalytic N-glycosylase domain MBD4cat. The conformational changes in MBD4cat and DNA substrates during their interaction were recorded in real time by stopped-flow detection of the fluorescence of tryptophan residues in the enzyme and fluorophores in DNA. A kinetic scheme of MBD4cat interaction with DNA was proposed, and the rate constants for the formation and decomposition of transient reaction intermediates were calculated. Using DNA substrates of different lengths, the formation of the catalytically active complex was shown to follow the primary DNA binding step which is responsible for the search and recognition of the modified base. The results reveal that in the primary complex of MBD4cat with DNA containing modified nucleotides, local melting and bending of the DNA strand occur. On the next step, when the catalytically competent conformation of the enzyme-substrate complex is formed, the modified nucleotide is everted from the double DNA helix into the active center and the void in the helix is filled by the enzyme's amino acids.
Collapse
Affiliation(s)
- D. A. Yakovlev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva ave. 8, Novosibirsk, 630090, Russia
| | - A. A. Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva ave. 8, Novosibirsk, 630090, Russia
| | - O. S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva ave. 8, Novosibirsk, 630090, Russia ,Department of Natural Sciences, Novosibirsk State University, Pirogova str. 2, Novosibirsk, 630090 , Russia
| | - N. A. Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Lavrentieva ave. 8, Novosibirsk, 630090, Russia ,Department of Natural Sciences, Novosibirsk State University, Pirogova str. 2, Novosibirsk, 630090 , Russia
| |
Collapse
|
40
|
Coey CT, Malik SS, Pidugu LS, Varney KM, Pozharski E, Drohat AC. Structural basis of damage recognition by thymine DNA glycosylase: Key roles for N-terminal residues. Nucleic Acids Res 2016; 44:10248-10258. [PMID: 27580719 PMCID: PMC5137436 DOI: 10.1093/nar/gkw768] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/20/2016] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
Abstract
Thymine DNA Glycosylase (TDG) is a base excision repair enzyme functioning in DNA repair and epigenetic regulation. TDG removes thymine from mutagenic G·T mispairs arising from deamination of 5-methylcytosine (mC), and it processes other deamination-derived lesions including uracil (U). Essential for DNA demethylation, TDG excises 5-formylcytosine and 5-carboxylcytosine, derivatives of mC generated by Tet (ten-eleven translocation) enzymes. Here, we report structural and functional studies of TDG82-308, a new construct containing 29 more N-terminal residues than TDG111-308, the construct used for previous structures of DNA-bound TDG. Crystal structures and NMR experiments demonstrate that most of these N-terminal residues are disordered, for substrate- or product-bound TDG82-308 Nevertheless, G·T substrate affinity and glycosylase activity of TDG82-308 greatly exceeds that of TDG111-308 and is equivalent to full-length TDG. We report the first high-resolution structures of TDG in an enzyme-substrate complex, for G·U bound to TDG82-308 (1.54 Å) and TDG111-308 (1.71 Å), revealing new enzyme-substrate contacts, direct and water-mediated. We also report a structure of the TDG82-308 product complex (1.70 Å). TDG82-308 forms unique enzyme-DNA interactions, supporting its value for structure-function studies. The results advance understanding of how TDG recognizes and removes modified bases from DNA, particularly those resulting from deamination.
Collapse
Affiliation(s)
- Christopher T Coey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Shuja S Malik
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Lakshmi S Pidugu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kristen M Varney
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,University of Maryland Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD 21201, USA.,Center for Biomolecular Therapeutics, Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
| | - Edwin Pozharski
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA .,University of Maryland Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD 21201, USA.,Center for Biomolecular Therapeutics, Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA .,University of Maryland Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD 21201, USA
| |
Collapse
|
41
|
Drohat AC, Coey CT. Role of Base Excision "Repair" Enzymes in Erasing Epigenetic Marks from DNA. Chem Rev 2016; 116:12711-12729. [PMID: 27501078 DOI: 10.1021/acs.chemrev.6b00191] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Base excision repair (BER) is one of several DNA repair pathways found in all three domains of life. BER counters the mutagenic and cytotoxic effects of damage that occurs continuously to the nitrogenous bases in DNA, and its critical role in maintaining genomic integrity is well established. However, BER also performs essential functions in processes other than DNA repair, where it acts on naturally modified bases in DNA. A prominent example is the central role of BER in mediating active DNA demethylation, a multistep process that erases the epigenetic mark 5-methylcytosine (5mC), and derivatives thereof, converting them back to cytosine. Herein, we review recent advances in the understanding of how BER mediates this critical component of epigenetic regulation in plants and animals.
Collapse
Affiliation(s)
- Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Christopher T Coey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| |
Collapse
|
42
|
Ludwig AK, Zhang P, Cardoso MC. Modifiers and Readers of DNA Modifications and Their Impact on Genome Structure, Expression, and Stability in Disease. Front Genet 2016; 7:115. [PMID: 27446199 PMCID: PMC4914596 DOI: 10.3389/fgene.2016.00115] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/06/2016] [Indexed: 12/16/2022] Open
Abstract
Cytosine base modifications in mammals underwent a recent expansion with the addition of several naturally occurring further modifications of methylcytosine in the last years. This expansion was accompanied by the identification of the respective enzymes and proteins reading and translating the different modifications into chromatin higher order organization as well as genome activity and stability, leading to the hypothesis of a cytosine code. Here, we summarize the current state-of-the-art on DNA modifications, the enzyme families setting the cytosine modifications and the protein families reading and translating the different modifications with emphasis on the mouse protein homologs. Throughout this review, we focus on functional and mechanistic studies performed on mammalian cells, corresponding mouse models and associated human diseases.
Collapse
Affiliation(s)
- Anne K Ludwig
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| | - M C Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technische Universität Darmstadt, Darmstadt Germany
| |
Collapse
|
43
|
Wood KH, Zhou Z. Emerging Molecular and Biological Functions of MBD2, a Reader of DNA Methylation. Front Genet 2016; 7:93. [PMID: 27303433 PMCID: PMC4880565 DOI: 10.3389/fgene.2016.00093] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/10/2016] [Indexed: 01/25/2023] Open
Abstract
DNA methylation is an epigenetic mark that is essential for many biological processes and is linked to diseases such as cancer. Methylation is usually associated with transcriptional silencing, but new research has challenged this model. Both transcriptional activation and repression have recently been found to be associated with DNA methylation in a context-specific manner. How DNA methylation patterns are interpreted into different functional output remains poorly understood. One mechanism involves the protein ‘readers’ of methylation, which includes the methyl-CpG binding domain (MBD) family of proteins. This review examines the molecular and biological functions of MBD2, which binds to CpG methylation and is an integral part of the nucleosome remodeling and histone deacetylation (NuRD) complex. MBD2 has been linked to immune system function and tumorigenesis, yet little is known about its functions in vivo. Recent studies have found the MBD2 protein is ubiquitously expressed, with relatively high levels in the lung, liver, and colon. Mbd2 null mice surprisingly show relatively mild phenotypes compared to mice with loss of function of other MBD proteins. This evidence has previously been interpreted as functional redundancy between the MBD proteins. Here, we examine and contextualize research that suggests MBD2 has unique properties and functions among the MBD proteins. These functions translate to recently described roles in the development and differentiation of multiple cell lineages, including pluripotent stem cells and various cell types of the immune system, as well as in tumorigenesis. We also consider possible models for the dynamic interactions between MBD2 and NuRD in different tissues in vivo. The functions of MBD2 may have direct therapeutic implications for several areas of human disease, including autoimmune conditions and cancer, in addition to providing insights into the actions of NuRD and chromatin regulation.
Collapse
Affiliation(s)
- Kathleen H Wood
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA, USA
| | - Zhaolan Zhou
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA, USA
| |
Collapse
|
44
|
Tomkova M, McClellan M, Kriaucionis S, Schuster-Boeckler B. 5-hydroxymethylcytosine marks regions with reduced mutation frequency in human DNA. eLife 2016; 5. [PMID: 27183007 PMCID: PMC4931910 DOI: 10.7554/elife.17082] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/13/2016] [Indexed: 12/21/2022] Open
Abstract
CpG dinucleotides are the main mutational hot-spot in most cancers. The characteristic elevated C>T mutation rate in CpG sites has been related to 5-methylcytosine (5mC), an epigenetically modified base which resides in CpGs and plays a role in transcription silencing. In brain nearly a third of 5mCs have recently been found to exist in the form of 5-hydroxymethylcytosine (5hmC), yet the effect of 5hmC on mutational processes is still poorly understood. Here we show that 5hmC is associated with an up to 53% decrease in the frequency of C>T mutations in a CpG context compared to 5mC. Tissue specific 5hmC patterns in brain, kidney and blood correlate with lower regional CpG>T mutation frequency in cancers originating in the respective tissues. Together our data reveal global and opposing effects of the two most common cytosine modifications on the frequency of cancer causing somatic mutations in different cell types.
Collapse
Affiliation(s)
- Marketa Tomkova
- Ludwig Cancer Research Oxford, University of Oxford, Oxford, United Kingdom
| | - Michael McClellan
- Ludwig Cancer Research Oxford, University of Oxford, Oxford, United Kingdom
| | | | | |
Collapse
|
45
|
Patel DJ. A Structural Perspective on Readout of Epigenetic Histone and DNA Methylation Marks. Cold Spring Harb Perspect Biol 2016; 8:a018754. [PMID: 26931326 DOI: 10.1101/cshperspect.a018754] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This article outlines the protein modules that target methylated lysine histone marks and 5mC DNA marks, and the molecular principles underlying recognition. The article focuses on the structural basis underlying readout of isolated marks by single reader molecules, as well as multivalent readout of multiple marks by linked reader cassettes at the histone tail and nucleosome level. Additional topics addressed include the role of histone mimics, cross talk between histone marks, technological developments at the genome-wide level, advances using chemical biology approaches, the linkage between histone and DNA methylation, the role for regulatory lncRNAs, and the promise of chromatin-based therapeutic modalities.
Collapse
Affiliation(s)
- Dinshaw J Patel
- Structural Biology Department, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| |
Collapse
|
46
|
Shimbo T, Wade PA. Proteins That Read DNA Methylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:303-320. [PMID: 27826844 DOI: 10.1007/978-3-319-43624-1_13] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Covalent modification of DNA via deposition of a methyl group at the 5' position on cytosine residues alters the chemical groups available for interaction in the major groove of DNA. The information content inherent in this modification alters the affinity and the specificity of DNA binding; some proteins favor interaction with methylated DNA, and others disfavor it. Molecular recognition of cytosine methylation by proteins often initiates sequential regulatory events which impact gene expression and chromatin structure. The known methyl-DNA-binding proteins have unique domains responsible for DNA methylation recognition: (1) the methyl-CpG-binding domain (MBD), (2) the C2H2 zinc finger domain, and (3) the SET- and RING finger-associated (SRA) domain. Structural analyses have revealed that each domain has a characteristic methylated DNA-binding pattern, and this difference in the recognition mechanism renders the DNA methylation mark able to transmit complicated biological information. Recent genetic and genomic studies have revealed novel functions of methyl-DNA-binding proteins. These emerging data have also provided glimpses into how methyl-DNA-binding proteins possess unique features and, presumably, functions. In this review, we summarize structural and biochemical analyses elucidating the mechanism for recognition of DNA methylation and correlate this information with emerging genomic and functional data.
Collapse
Affiliation(s)
- Takashi Shimbo
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, USA
| | - Paul A Wade
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, USA.
| |
Collapse
|
47
|
Woods RD, O'Shea VL, Chu A, Cao S, Richards JL, Horvath MP, David SS. Structure and stereochemistry of the base excision repair glycosylase MutY reveal a mechanism similar to retaining glycosidases. Nucleic Acids Res 2015; 44:801-10. [PMID: 26673696 PMCID: PMC4737165 DOI: 10.1093/nar/gkv1469] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 12/02/2015] [Indexed: 12/13/2022] Open
Abstract
MutY adenine glycosylases prevent DNA mutations by excising adenine from promutagenic 8-oxo-7,8-dihydroguanine (OG):A mismatches. Here, we describe structural features of the MutY active site bound to an azaribose transition state analog which indicate a catalytic role for Tyr126 and approach of the water nucleophile on the same side as the departing adenine base. The idea that Tyr126 participates in catalysis, recently predicted by modeling calculations, is strongly supported by mutagenesis and by seeing close contact between the hydroxyl group of this residue and the azaribose moiety of the transition state analog. NMR analysis of MutY methanolysis products corroborates a mechanism for adenine removal with retention of stereochemistry. Based on these results, we propose a revised mechanism for MutY that involves two nucleophilic displacement steps akin to the mechanisms accepted for 'retaining' O-glycosidases. This new-for-MutY yet familiar mechanism may also be operative in related base excision repair glycosylases and provides a critical framework for analysis of human MutY (MUTYH) variants associated with inherited colorectal cancer.
Collapse
Affiliation(s)
- Ryan D Woods
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Valerie L O'Shea
- Department of Chemistry, University of California, Davis, CA 95616, USA Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Aurea Chu
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Sheng Cao
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Jody L Richards
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Martin P Horvath
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Sheila S David
- Department of Chemistry, University of California, Davis, CA 95616, USA
| |
Collapse
|
48
|
Du Q, Luu PL, Stirzaker C, Clark SJ. Methyl-CpG-binding domain proteins: readers of the epigenome. Epigenomics 2015; 7:1051-73. [DOI: 10.2217/epi.15.39] [Citation(s) in RCA: 265] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How DNA methylation is interpreted and influences genome regulation remains largely unknown. Proteins of the methyl-CpG-binding domain (MBD) family are primary candidates for the readout of DNA methylation as they recruit chromatin remodelers, histone deacetylases and methylases to methylated DNA associated with gene repression. MBD protein binding requires both functional MBD domains and methyl-CpGs; however, some MBD proteins also bind unmethylated DNA and active regulatory regions via alternative regulatory domains or interaction with the nucleosome remodeling deacetylase (NuRD/Mi-2) complex members. Mutations within MBD domains occur in many diseases, including neurological disorders and cancers, leading to loss of MBD binding specificity to methylated sites and gene deregulation. Here, we summarize the current state of knowledge about MBD proteins and their role as readers of the epigenome.
Collapse
Affiliation(s)
- Qian Du
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Phuc-Loi Luu
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
| | - Clare Stirzaker
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
- St Vincent's Clinical School, University of NSW, Darlinghurst, NSW 2010, Australia
| |
Collapse
|
49
|
Dong E, Ruzicka WB, Grayson D, Guidotti A. DNA-methyltransferase1 (DNMT1) binding to CpG rich GABAergic and BDNF promoters is increased in the brain of schizophrenia and bipolar disorder patients. Schizophr Res 2015; 167:35-41. [PMID: 25476119 PMCID: PMC4451449 DOI: 10.1016/j.schres.2014.10.030] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/16/2014] [Accepted: 10/19/2014] [Indexed: 10/24/2022]
Abstract
The down regulation of glutamic acid decarboxylase67 (GAD1), reelin (RELN), and BDNF expression in brain of schizophrenia (SZ) and bipolar (BP) disorder patients is associated with overexpression of DNA methyltransferase1 (DNMT1) and ten-eleven translocase methylcytosine dioxygenase1 (TET1). DNMT1 and TET1 belong to families of enzymes that methylate and hydroxymethylate cytosines located proximal to and within cytosine phosphodiester guanine (CpG) islands of many gene promoters, respectively. Altered promoter methylation may be one mechanism underlying the down-regulation of GABAergic and glutamatergic gene expression. However, recent reports suggest that both DNMT1 and TET1 directly bind to unmethylated CpG rich promoters through their respective Zinc Finger (ZF-CXXC) domains. We report here, that the binding of DNMT1 to GABAergic (GAD1, RELN) and glutamatergic (BDNF-IX) promoters is increased in SZ and BP disorder patients and this increase does not necessarily correlate with enrichment in promoter methylation. The increased DNMT1 binding to these promoter regions is detected in the cortex but not in the cerebellum of SZ and BP disorder patients, suggesting a brain region and neuron specific dependent mechanism. Increased binding of DNMT1 positively correlates with increased expression of DNMT1 and with increased binding of MBD2. In contrast, the binding of TET1 to RELN, GAD1 and BDNF-IX promoters failed to change. These data are consistent with the hypothesis that the down-regulation of specific GABAergic and glutamatergic genes in SZ and BP disorder patients may be mediated, at least in part, by a brain region specific and neuronal-activity dependent DNMT1 action that is likely independent of its DNA methylation activity.
Collapse
Affiliation(s)
- E. Dong
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago
| | - W. B. Ruzicka
- Program in Structural and Molecular Neuroscience, McLean Hospital., Belmont, MA,Department of Psychiatry, Harvard Medical School, Boston, MA
| | - D.R. Grayson
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago
| | - A. Guidotti
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago,Corresponding author: A. Guidotti, 1601 W. Taylor St., Chicago, IL 60612, , 312-413-4594
| |
Collapse
|
50
|
Rodger EJ, Chatterjee A, Morison IM. 5-hydroxymethylcytosine: a potential therapeutic target in cancer. Epigenomics 2015; 6:503-14. [PMID: 25431943 DOI: 10.2217/epi.14.39] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The ten-eleven translocation enzymes catalyze the conversion of 5-methylcytosine to 5-hydroxymethylcytosine, a distinct epigenetic mark that has an integral role in active demethylation. Genes that regulate the distribution and amount of 5-hydroxymethylcytosine in the genome could be suitable therapeutic targets to correct abnormal methylation in cancer. Here, we present an overview of the role of the 5-hydroxymethylcytosine pathway in human disease and discuss the emergence of innovative techniques that can map the distribution of 5-hydroxymethylcytosine at high resolution. In the context of current epigenetic therapies and by using recent functional studies, we propose plausible mechanisms to target the 5-hydroxymethylcytosine pathway in cancer. As the study of 5-hydroxymethylcytosine is still in its infancy, we provide future perspectives.
Collapse
Affiliation(s)
- Euan J Rodger
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | | | | |
Collapse
|