1
|
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
|
2
|
Torgasheva NA, Diatlova EA, Grin IR, Endutkin AV, Mechetin GV, Vokhtantsev IP, Yudkina AV, Zharkov DO. Noncatalytic Domains in DNA Glycosylases. Int J Mol Sci 2022; 23:ijms23137286. [PMID: 35806289 PMCID: PMC9266487 DOI: 10.3390/ijms23137286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 02/04/2023] Open
Abstract
Many proteins consist of two or more structural domains: separate parts that have a defined structure and function. For example, in enzymes, the catalytic activity is often localized in a core fragment, while other domains or disordered parts of the same protein participate in a number of regulatory processes. This situation is often observed in many DNA glycosylases, the proteins that remove damaged nucleobases thus initiating base excision DNA repair. This review covers the present knowledge about the functions and evolution of such noncatalytic parts in DNA glycosylases, mostly concerned with the human enzymes but also considering some unique members of this group coming from plants and prokaryotes.
Collapse
Affiliation(s)
- Natalia A. Torgasheva
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Evgeniia A. Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Inga R. Grin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Grigory V. Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Ivan P. Vokhtantsev
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
| | - Anna V. Yudkina
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Avenue, 630090 Novosibirsk, Russia; (N.A.T.); (E.A.D.); (I.R.G.); (A.V.E.); (G.V.M.); (I.P.V.); (A.V.Y.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia
- Correspondence:
| |
Collapse
|
3
|
Park JC, Jang HK, Kim J, Han JH, Jung Y, Kim K, Bae S, Cha HJ. High expression of uracil DNA glycosylase determines C to T substitution in human pluripotent stem cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 27:175-183. [PMID: 34976436 PMCID: PMC8688811 DOI: 10.1016/j.omtn.2021.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/28/2021] [Indexed: 10/29/2022]
Abstract
Precise genome editing of human pluripotent stem cells (hPSCs) is crucial not only for basic science but also for biomedical applications such as ex vivo stem cell therapy and genetic disease modeling. However, hPSCs have unique cellular properties compared to somatic cells. For instance, hPSCs are extremely susceptible to DNA damage, and therefore Cas9-mediated DNA double-strand breaks (DSB) induce p53-dependent cell death, resulting in low Cas9 editing efficiency. Unlike Cas9 nucleases, base editors including cytosine base editor (CBE) and adenine base editor (ABE) can efficiently substitute single nucleotides without generating DSBs at target sites. Here, we found that the editing efficiency of CBE was significantly lower than that of ABE in human embryonic stem cells (hESCs), which are associated with high expression of DNA glycosylases, the key component of the base excision repair pathway. Sequential depletion of DNA glycosylases revealed that high expression of uracil DNA glycosylase (UNG) not only resulted in low editing efficiency but also affected CBE product purity (i.e., C to T) in hESCs. Therefore, additional suppression of UNG via transient knockdown would also improve C to T base substitutions in hESCs. These data suggest that the unique cellular characteristics of hPSCs could determine the efficiency of precise genome editing.
Collapse
Affiliation(s)
- Ju-Chan Park
- College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hyeon-Ki Jang
- Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Jumee Kim
- College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jun Hee Han
- Department of Chemistry, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Youngri Jung
- Department of Chemistry, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Keuntae Kim
- College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Sangsu Bae
- Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, Republic of Korea
- Department of Chemistry, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Hyuk-Jin Cha
- College of Pharmacy, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| |
Collapse
|
4
|
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
|
5
|
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
|
6
|
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]
|
7
|
Prasad R, Yen TJ, Bellacosa A. Active DNA demethylation-The epigenetic gatekeeper of development, immunity, and cancer. ADVANCED GENETICS (HOBOKEN, N.J.) 2020; 2:e10033. [PMID: 36618446 PMCID: PMC9744510 DOI: 10.1002/ggn2.10033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 01/11/2023]
Abstract
DNA methylation is a critical process in the regulation of gene expression with dramatic effects in development and continually expanding roles in oncogenesis. 5-Methylcytosine was once considered to be an inherited and stably repressive epigenetic mark, which can be only removed by passive dilution during multiple rounds of DNA replication. However, in the past two decades, physiologically controlled DNA demethylation and deamination processes have been identified, thereby revealing the function of cytosine methylation as a highly regulated and complex state-not simply a static, inherited signature or binary on-off switch. Alongside these fundamental discoveries, clinical studies over the past decade have revealed the dramatic consequences of aberrant DNA demethylation. In this review we discuss DNA demethylation and deamination in the context of 5-methylcytosine as critical processes for physiological and physiopathological transitions within three states-development, immune maturation, and oncogenic transformation; and we describe the expanding role of DNA demethylating drugs as therapeutic agents in cancer.
Collapse
Affiliation(s)
- Rahul Prasad
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Timothy J. Yen
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer CenterPhiladelphiaPennsylvaniaUSA
| |
Collapse
|
8
|
Lenz SAP, Li D, Wetmore SD. Insights into the Direct Oxidative Repair of Etheno Lesions: MD and QM/MM Study on the Substrate Scope of ALKBH2 and AlkB. DNA Repair (Amst) 2020; 96:102944. [PMID: 33161373 DOI: 10.1016/j.dnarep.2020.102944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 01/09/2023]
Abstract
E. coli AlkB and human ALKBH2 belong to the AlkB family enzymes, which contain several α-ketoglutarate (α-KG)/Fe(II)-dependent dioxygenases that repair alkylated DNA. Specifically, the AlkB enzymes catalyze decarboxylation of α-KG to generate a high-valent Fe(IV)-oxo species that oxidizes alkyl groups on DNA adducts. AlkB and ALKBH2 have been reported to differentially repair select etheno adducts, with preferences for 1,N6-ethenoadenine (1,N6-εA) and 3,N4-ethenocytosine (3,N4-εC) over 1,N2-ethenoguanine (1,N2-εG). However, N2,3-ethenoguanine (N2,3-εG), the most common etheno adduct, is not repaired by the AlkB enzymes. Unfortunately, a structural understanding of the differential activity of E. coli AlkB and human ALKBH2 is lacking due to challenges acquiring atomistic details for a range of substrates using experiments. This study uses both molecular dynamics (MD) simulations and ONIOM(QM:MM) calculations to determine how the active site changes upon binding each etheno adduct and characterizes the corresponding catalytic impacts. Our data reveal that the preferred etheno substrates (1,N6-εA and 3,N4-εC) form favorable interactions with catalytic residues that situate the lesion near the Fe(IV)-oxo species and permit efficient oxidation. In contrast, although the damage remains correctly aligned with respect to the Fe(IV)-oxo moiety, repair of 1,N2-εG is mitigated by increased solvation of the active site and a larger distance between Fe(IV)-oxo and the aberrant carbons. Binding of non-substrate N2,3-εG in the active site disrupts key DNA-enzyme interactions, and positions the aberrant carbon atoms even further from the Fe(IV)-oxo species, leading to prohibitively high barriers for oxidative catalysis. Overall, our calculations provide the first structural insight required to rationalize the experimentally-reported substrate specificities of AlkB and ALKBH2 and thereby highlight the roles of several active site residues in the repair of etheno adducts that directly correlates with available experimental data. These proposed catalytic strategies can likely be generalized to other α-KG/Fe(II)-dependent dioxygenases that play similar critical biological roles, including epigenetic and post-translational regulation.
Collapse
Affiliation(s)
- Stefan A P Lenz
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| |
Collapse
|
9
|
Reading Targeted DNA Damage in the Active Demethylation Pathway: Role of Accessory Domains of Eukaryotic AP Endonucleases and Thymine-DNA Glycosylases. J Mol Biol 2020:S0022-2836(19)30720-X. [DOI: 10.1016/j.jmb.2019.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/24/2019] [Accepted: 12/05/2019] [Indexed: 01/07/2023]
|
10
|
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]
|
11
|
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
|
12
|
Sannai M, Doneddu V, Giri V, Seeholzer S, Nicolas E, Yip SC, Bassi MR, Mancuso P, Cortellino S, Cigliano A, Lurie R, Ding H, Chernoff J, Sobol RW, Yen TJ, Bagella L, Bellacosa A. Modification of the base excision repair enzyme MBD4 by the small ubiquitin-like molecule SUMO1. DNA Repair (Amst) 2019; 82:102687. [PMID: 31476572 PMCID: PMC6785017 DOI: 10.1016/j.dnarep.2019.102687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/21/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
The base excision repair DNA N-glycosylase MBD4 (also known as MED1), an interactor of the DNA mismatch repair protein MLH1, plays a central role in the maintenance of genomic stability of CpG sites by removing thymine and uracil from G:T and G:U mismatches, respectively. MBD4 is also involved in DNA damage response and transcriptional regulation. The interaction with other proteins is likely critical for understanding MBD4 functions. To identify novel proteins that interact with MBD4, we used tandem affinity purification (TAP) from HEK-293 cells. The MBD4-TAP fusion and its co-associated proteins were purified sequentially on IgG and calmodulin affinity columns; the final eluate was shown to contain MLH1 by western blotting, and MBD4-associated proteins were identified by mass spectrometry. Bands with molecular weight higher than that expected for MBD4 (˜66 kD) yielded peptides corresponding to MBD4 itself and the small ubiquitin-like molecule-1 (SUMO1), suggesting that MBD4 is sumoylated in vivo. MBD4 sumoylation was validated by co-immunoprecipitation in HEK-293 and MCF7 cells, and by an in vitrosumoylation assay. Sequence and mutation analysis identified three main sumoylation sites: MBD4 is sumoylated preferentially on K137, with additional sumoylation at K215 and K377. Patterns of MBD4 sumoylation were altered, in a DNA damage-specific way, by the anti-metabolite 5-fluorouracil, the alkylating agent N-Methyl-N-nitrosourea and the crosslinking agent cisplatin. MCF7 extract expressing sumoylated MBD4 displays higher thymine glycosylase activity than the unmodified species. Of the 67 MBD4 missense mutations reported in The Cancer Genome Atlas, 14 (20.9%) map near sumoylation sites. These results indicate that MBD4 is sumoylated in vivo in a DNA damage-specific manner, and suggest that sumoylation serves to regulate its repair activity and could be compromised in cancer. This study expands the role played by sumoylation in fine-tuning DNA damage response and repair.
Collapse
Affiliation(s)
- Mara Sannai
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Valentina Doneddu
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA; Department of Biomedical Sciences, University of Sassari, Sassari, 07100, Italy
| | - Veda Giri
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Steven Seeholzer
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia PA, 19104, USA
| | - Emmanuelle Nicolas
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Shu-Chin Yip
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Maria Rosaria Bassi
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Pietro Mancuso
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Salvatore Cortellino
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Antonio Cigliano
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Rebecca Lurie
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Hua Ding
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia PA, 19104, USA
| | - Jonathan Chernoff
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Robert W Sobol
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA
| | - Timothy J Yen
- Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA
| | - Luigi Bagella
- Department of Biomedical Sciences, University of Sassari, Sassari, 07100, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, 19122, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA, 19111, USA.
| |
Collapse
|
13
|
Roldán-Arjona T, Ariza RR, Córdoba-Cañero D. DNA Base Excision Repair in Plants: An Unfolding Story With Familiar and Novel Characters. FRONTIERS IN PLANT SCIENCE 2019; 10:1055. [PMID: 31543887 PMCID: PMC6728418 DOI: 10.3389/fpls.2019.01055] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/30/2019] [Indexed: 05/05/2023]
Abstract
Base excision repair (BER) is a critical genome defense pathway that deals with a broad range of non-voluminous DNA lesions induced by endogenous or exogenous genotoxic agents. BER is a complex process initiated by the excision of the damaged base, proceeds through a sequence of reactions that generate various DNA intermediates, and culminates with restoration of the original DNA structure. BER has been extensively studied in microbial and animal systems, but knowledge in plants has lagged behind until recently. Results obtained so far indicate that plants share many BER factors with other organisms, but also possess some unique features and combinations. Plant BER plays an important role in preserving genome integrity through removal of damaged bases. However, it performs additional important functions, such as the replacement of the naturally modified base 5-methylcytosine with cytosine in a plant-specific pathway for active DNA demethylation.
Collapse
Affiliation(s)
- Teresa Roldán-Arjona
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- Department of Genetics, University of Córdoba, Córdoba, Spain
- Reina Sofia University Hospital, Córdoba, Spain
| | - Rafael R. Ariza
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- Department of Genetics, University of Córdoba, Córdoba, Spain
- Reina Sofia University Hospital, Córdoba, Spain
| | - Dolores Córdoba-Cañero
- Maimónides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain
- Department of Genetics, University of Córdoba, Córdoba, Spain
- Reina Sofia University Hospital, Córdoba, Spain
| |
Collapse
|
14
|
A rapid, safe, and quantitative in vitro assay for measurement of uracil-DNA glycosylase activity. J Mol Med (Berl) 2019; 97:991-1001. [DOI: 10.1007/s00109-019-01788-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 12/26/2022]
|
15
|
The DNA Methylation Machinery. Clin Epigenetics 2019. [DOI: 10.1007/978-981-13-8958-0_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
|
16
|
Ginder GD, Williams DC. Readers of DNA methylation, the MBD family as potential therapeutic targets. Pharmacol Ther 2017; 184:98-111. [PMID: 29128342 DOI: 10.1016/j.pharmthera.2017.11.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
DNA methylation represents a fundamental epigenetic modification that regulates chromatin architecture and gene transcription. Many diseases, including cancer, show aberrant methylation patterns that contribute to the disease phenotype. DNA methylation inhibitors have been used to block methylation dependent gene silencing to treat hematopoietic neoplasms and to restore expression of developmentally silenced genes. However, these inhibitors disrupt methylation globally and show significant off-target toxicities. As an alternative approach, we have been studying readers of DNA methylation, the 5-methylcytosine binding domain family of proteins, as potential therapeutic targets to restore expression of aberrantly and developmentally methylated and silenced genes. In this review, we discuss the role of DNA methylation in gene regulation and cancer development, the structure and function of the 5-methylcytosine binding domain family of proteins, and the possibility of targeting the complexes these proteins form to treat human disease.
Collapse
Affiliation(s)
- Gordon D Ginder
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, United States; Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, United States; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, United States.
| | - David C Williams
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States.
| |
Collapse
|
17
|
Chaim IA, Gardner A, Wu J, Iyama T, Wilson DM, Samson LD. A novel role for transcription-coupled nucleotide excision repair for the in vivo repair of 3,N4-ethenocytosine. Nucleic Acids Res 2017; 45:3242-3252. [PMID: 28115629 PMCID: PMC5389632 DOI: 10.1093/nar/gkx015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/20/2017] [Indexed: 12/13/2022] Open
Abstract
Etheno (ε) DNA base adducts are highly mutagenic lesions produced endogenously via reactions with lipid peroxidation (LPO) products. Cancer-promoting conditions, such as inflammation, can induce persistent oxidative stress and increased LPO, resulting in the accumulation of ε-adducts in different tissues. Using a recently described fluorescence multiplexed host cell reactivation assay, we show that a plasmid reporter bearing a site-specific 3,N4-ethenocytosine (εC) causes transcriptional blockage. Notably, this blockage is exacerbated in Cockayne Syndrome and xeroderma pigmentosum patient-derived lymphoblastoid and fibroblast cells. Parallel RNA-Seq expression analysis of the plasmid reporter identifies novel transcriptional mutagenesis properties of εC. Our studies reveal that beyond the known pathways, such as base excision repair, the process of transcription-coupled nucleotide excision repair plays a role in the removal of εC from the genome, and thus in the protection of cells and tissues from collateral damage induced by inflammatory responses.
Collapse
Affiliation(s)
- Isaac A Chaim
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alycia Gardner
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jie Wu
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility in the Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Teruaki Iyama
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA
| | - Leona D Samson
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| |
Collapse
|
18
|
Tudek B, Zdżalik-Bielecka D, Tudek A, Kosicki K, Fabisiewicz A, Speina E. Lipid peroxidation in face of DNA damage, DNA repair and other cellular processes. Free Radic Biol Med 2017; 107:77-89. [PMID: 27908783 DOI: 10.1016/j.freeradbiomed.2016.11.043] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/20/2016] [Accepted: 11/27/2016] [Indexed: 01/09/2023]
Abstract
Exocyclic adducts to DNA bases are formed as a consequence of exposure to certain environmental carcinogens as well as inflammation and lipid peroxidation (LPO). Complex family of LPO products gives rise to a variety of DNA adducts, which can be grouped in two classes: (i) small etheno-type adducts of strong mutagenic potential, and (ii) bulky, propano-type adducts, which block replication and transcription, and are lethal lesions. Etheno-DNA adducts are removed from the DNA by base excision repair (BER), AlkB and nucleotide incision repair enzymes (NIR), while substituted propano-type lesions by nucleotide excision repair (NER) and homologous recombination (HR). Changes of the level and activity of several enzymes removing exocyclic adducts from the DNA was reported during carcinogenesis. Also several beyond repair functions of these enzymes, which participate in regulation of cell proliferation and growth, as well as RNA processing was recently described. In addition, adducts of LPO products to proteins was reported during aging and age-related diseases. The paper summarizes pathways for exocyclic adducts removal and describes how proteins involved in repair of these adducts can modify pathological states of the organism.
Collapse
Affiliation(s)
- Barbara Tudek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Daria Zdżalik-Bielecka
- Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ksiecia Trojdena 4, 02-109 Warsaw, Poland
| | - Agnieszka Tudek
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Mollers Alle 3, 8000 Aarhus, Denmark
| | - Konrad Kosicki
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Fabisiewicz
- Department of Molecular and Translational Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Roentgena 5, Warsaw 02-781, Poland
| | - Elżbieta Speina
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| |
Collapse
|
19
|
Mohamadkhani A, Pourshams A, Viti J, Cellai F, Mortazavi K, Sharafkhah M, Sotoudeh M, Malekzadeh R, Boffetta P, Peluso M. Pancreatic Cancer is Associated with Peripheral Leukocyte Oxidative DNA Damage. Asian Pac J Cancer Prev 2017; 18:1349-1355. [PMID: 28612585 PMCID: PMC5555546 DOI: 10.22034/apjcp.2017.18.5.1349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background: DNA damage accumulation has been linked to the cancer phenotype. The purpose of this study was to compare the levels of DNA base 8-hydroxy-2’-deoxyguanosine (8-OHdG) and C-reactive protein (CRP) inflammatory markers in healthy controls and pancreatic cancer patients from a hospital-based case-control study. Materials and Methods: Fifty-five pancreatic cancer patients and 55 healthy controls were enrolled from a pool of patients referred to the Endoscopic Ultrasound (EUS) center. Analysis of DNA content of peripheral blood cells was conducted for 8-OHdG with the 32P-postlabelling assay. Serum CRP levels were measured by high-sensitivity assays and demographic data for comparison were collected from individual medical records. Results: The group of cases showed significant increased median (IQR) 8-OHdG DNA adducts/106 nucleotides and CRP compared to the controls (208.8 (138.0-340.8) vs 121.8 (57.7-194.8) RAL value; P<0.001) and (3.5 (1.5-8.6) vs 0.5 (0.2-1.5) mg/L P<0.001). A number of conditional regression models confirmed associations of pancreatic cancer with oxidative DNA damage in peripheral leukocytes. Conclusions: Our findings suggest the importance of leukocyte 8-OHdG adducts as an indicator for systemic oxidative DNA damage in pancreatic cancer patients. In addition to increase in the CRP inflammatory marker, this supports the impact of inflammation in the occurrence of pancreatic cancer as well as inflammatory responses during cancer development.
Collapse
Affiliation(s)
- Ashraf Mohamadkhani
- Liver and Pancreatobiliary Diseases Research Center, Digestive Disease Research Institute, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran. ,
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Mutational spectra of aflatoxin B 1 in vivo establish biomarkers of exposure for human hepatocellular carcinoma. Proc Natl Acad Sci U S A 2017; 114:E3101-E3109. [PMID: 28351974 DOI: 10.1073/pnas.1700759114] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aflatoxin B1 (AFB1) and/or hepatitis B and C viruses are risk factors for human hepatocellular carcinoma (HCC). Available evidence supports the interpretation that formation of AFB1-DNA adducts in hepatocytes seeds a population of mutations, mainly G:C→T:A, and viral processes synergize to accelerate tumorigenesis, perhaps via inflammation. Responding to a need for early-onset evidence predicting disease development, highly accurate duplex sequencing was used to monitor acquisition of high-resolution mutational spectra (HRMS) during the process of hepatocarcinogenesis. Four-day-old male mice were treated with AFB1 using a regimen that induced HCC within 72 wk. For analysis, livers were separated into tumor and adjacent cellular fractions. HRMS of cells surrounding the tumors revealed predominantly G:C→T:A mutations characteristic of AFB1 exposure. Importantly, 25% of all mutations were G→T in one trinucleotide context (CGC; the underlined G is the position of the mutation), which is also a hotspot mutation in human liver tumors whose incidence correlates with AFB1 exposure. The technology proved sufficiently sensitive that the same distinctive spectrum was detected as early as 10 wk after dosing, well before evidence of neoplasia. Additionally, analysis of tumor tissue revealed a more complex pattern than observed in surrounding hepatocytes; tumor HRMS were a composite of the 10-wk spectrum and a more heterogeneous set of mutations that emerged during tumor outgrowth. We propose that the 10-wk HRMS reflects a short-term mutational response to AFB1, and, as such, is an early detection metric for AFB1-induced liver cancer in this mouse model that will be a useful tool to reconstruct the molecular etiology of human hepatocarcinogenesis.
Collapse
|
21
|
Nakamura T, Murakami K, Tada H, Uehara Y, Nogami J, Maehara K, Ohkawa Y, Saitoh H, Nishitani H, Ono T, Nishi R, Yokoi M, Sakai W, Sugasawa K. Thymine DNA glycosylase modulates DNA damage response and gene expression by base excision repair-dependent and independent mechanisms. Genes Cells 2017; 22:392-405. [PMID: 28318075 DOI: 10.1111/gtc.12481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 02/01/2017] [Indexed: 02/04/2023]
Abstract
Thymine DNA glycosylase (TDG) is a base excision repair (BER) enzyme, which is implicated in correction of deamination-induced DNA mismatches, the DNA demethylation process and regulation of gene expression. Because of these pivotal roles associated, it is crucial to elucidate how the TDG functions are appropriately regulated in vivo. Here, we present evidence that the TDG protein undergoes degradation upon various types of DNA damage, including ultraviolet light (UV). The UV-induced degradation of TDG was dependent on proficiency in nucleotide excision repair and on CRL4CDT2 -mediated ubiquitination that requires a physical interaction between TDG and DNA polymerase clamp PCNA. Using the Tdg-deficient mouse embryonic fibroblasts, we found that ectopic expression of TDG compromised cellular survival after UV irradiation and repair of UV-induced DNA lesions. These negative effects on cellular UV responses were alleviated by introducing mutations in TDG that impaired its BER function. The expression of TDG induced a large-scale alteration in the gene expression profile independently of its DNA glycosylase activity, whereas a subset of genes was affected by the catalytic activity of TDG. Our results indicate the presence of BER-dependent and BER-independent functions of TDG, which are involved in regulation of cellular DNA damage responses and gene expression patterns.
Collapse
Affiliation(s)
- Tomohumi Nakamura
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Kouichi Murakami
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Haruto Tada
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Yoshihiko Uehara
- Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Jumpei Nogami
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Kazumitsu Maehara
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Yasuyuki Ohkawa
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Hisato Saitoh
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Hideo Nishitani
- Graduate School of Life Science, University of Hyogo, Kamigori, 678-1297, Japan
| | - Tetsuya Ono
- Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ryotaro Nishi
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
| | - Masayuki Yokoi
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Wataru Sakai
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Kaoru Sugasawa
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| |
Collapse
|
22
|
Repair of oxidatively induced DNA damage by DNA glycosylases: Mechanisms of action, substrate specificities and excision kinetics. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 771:99-127. [PMID: 28342455 DOI: 10.1016/j.mrrev.2017.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Indexed: 02/07/2023]
Abstract
Endogenous and exogenous reactive species cause oxidatively induced DNA damage in living organisms by a variety of mechanisms. As a result, a plethora of mutagenic and/or cytotoxic products are formed in cellular DNA. This type of DNA damage is repaired by base excision repair, although nucleotide excision repair also plays a limited role. DNA glycosylases remove modified DNA bases from DNA by hydrolyzing the glycosidic bond leaving behind an apurinic/apyrimidinic (AP) site. Some of them also possess an accompanying AP-lyase activity that cleaves the sugar-phosphate chain of DNA. Since the first discovery of a DNA glycosylase, many studies have elucidated the mechanisms of action, substrate specificities and excision kinetics of these enzymes present in all living organisms. For this purpose, most studies used single- or double-stranded oligodeoxynucleotides with a single DNA lesion embedded at a defined position. High-molecular weight DNA with multiple base lesions has been used in other studies with the advantage of the simultaneous investigation of many DNA base lesions as substrates. Differences between the substrate specificities and excision kinetics of DNA glycosylases have been found when these two different substrates were used. Some DNA glycosylases possess varying substrate specificities for either purine-derived lesions or pyrimidine-derived lesions, whereas others exhibit cross-activity for both types of lesions. Laboratory animals with knockouts of the genes of DNA glycosylases have also been used to provide unequivocal evidence for the substrates, which had previously been found in in vitro studies, to be the actual substrates in vivo as well. On the basis of the knowledge gained from the past studies, efforts are being made to discover small molecule inhibitors of DNA glycosylases that may be used as potential drugs in cancer therapy.
Collapse
|
23
|
Suzuki S, Iwaizumi M, Tseng-Rogenski S, Hamaya Y, Miyajima H, Kanaoka S, Sugimoto K, Carethers JM. Production of truncated MBD4 protein by frameshift mutation in DNA mismatch repair-deficient cells enhances 5-fluorouracil sensitivity that is independent of hMLH1 status. Cancer Biol Ther 2016; 17:760-8. [PMID: 27115207 DOI: 10.1080/15384047.2016.1178430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Methyl-CpG binding domain protein 4 (MBD4) is a DNA glycosylase that can remove 5-fluorodeoxyuracil from DNA as well as repair T:G or U:G mismatches. MBD4 is a target for frameshift mutation with DNA mismatch repair (MMR) deficiency, creating a truncated MBD4 protein (TruMBD4) that lacks its glycosylase domain. Here we show that TruMBD4 plays an important role for enhancing 5-fluorouracil (5FU) sensitivity in MMR-deficient colorectal cancer cells. We found biochemically that TruMBD4 binds to 5FU incorporated into DNA with higher affinity than MBD4. TruMBD4 reduced the 5FU affinity of the MMR recognition complexes that determined 5FU sensitivity by previous reports, suggesting other mechanisms might be operative to trigger cytotoxicity. To analyze overall 5FU sensitivity with TruMBD4, we established TruMBD4 overexpression in hMLH1-proficient or -deficient colorectal cancer cells followed by treatment with 5FU. 5FU-treated TruMBD4 cells demonstrated diminished growth characteristics compared to controls, independently of hMLH1 status. Flow cytometry revealed more 5FU-treated TruMBD4 cells in S phase than controls. We conclude that patients with MMR-deficient cancers, which show characteristic resistance to 5FU therapy, may be increased for 5FU sensitivity via secondary frameshift mutation of the base excision repair gene MBD4.
Collapse
Affiliation(s)
- Satoshi Suzuki
- a First Department of Medicine , Hamamatsu University School of Medicine , Hamamatsu , Shizuoka , Japan
| | - Moriya Iwaizumi
- a First Department of Medicine , Hamamatsu University School of Medicine , Hamamatsu , Shizuoka , Japan.,b Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan , Ann Arbor , MA , USA
| | - Stephanie Tseng-Rogenski
- b Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan , Ann Arbor , MA , USA
| | - Yasushi Hamaya
- a First Department of Medicine , Hamamatsu University School of Medicine , Hamamatsu , Shizuoka , Japan.,b Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan , Ann Arbor , MA , USA
| | - Hiroaki Miyajima
- a First Department of Medicine , Hamamatsu University School of Medicine , Hamamatsu , Shizuoka , Japan
| | - Shigeru Kanaoka
- c Department of Gastroenterology , Hamamatsu Medical Center , Shizuoka , Japan
| | - Ken Sugimoto
- a First Department of Medicine , Hamamatsu University School of Medicine , Hamamatsu , Shizuoka , Japan
| | - John M Carethers
- b Division of Gastroenterology, Department of Internal Medicine and Department of Human Genetics, University of Michigan , Ann Arbor , MA , USA
| |
Collapse
|
24
|
Huehls AM, Huntoon CJ, Joshi PM, Baehr CA, Wagner JM, Wang X, Lee MY, Karnitz LM. Genomically Incorporated 5-Fluorouracil that Escapes UNG-Initiated Base Excision Repair Blocks DNA Replication and Activates Homologous Recombination. Mol Pharmacol 2015; 89:53-62. [PMID: 26494862 DOI: 10.1124/mol.115.100164] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/21/2015] [Indexed: 12/17/2022] Open
Abstract
5-Fluorouracil (5-FU) and its metabolite 5-fluorodeoxyuridine (FdUrd, floxuridine) are chemotherapy agents that are converted to 5-fluorodeoxyuridine monophosphate (FdUMP) and 5-fluorodeoxyuridine triphosphate (FdUTP). FdUMP inhibits thymidylate synthase and causes the accumulation of uracil in the genome, whereas FdUTP is incorporated by DNA polymerases as 5-FU in the genome; however, it remains unclear how either genomically incorporated U or 5-FU contributes to killing. We show that depletion of the uracil DNA glycosylase (UNG) sensitizes tumor cells to FdUrd. Furthermore, we show that UNG depletion does not sensitize cells to the thymidylate synthase inhibitor (raltitrexed), which induces uracil but not 5-FU accumulation, thus indicating that genomically incorporated 5-FU plays a major role in the antineoplastic effects of FdUrd. We also show that 5-FU metabolites do not block the first round of DNA synthesis but instead arrest cells at the G1/S border when cells again attempt replication and activate homologous recombination (HR). This arrest is not due to 5-FU lesions blocking DNA polymerase δ but instead depends, in part, on the thymine DNA glycosylase. Consistent with the activation of HR repair, disruption of HR sensitized cells to FdUrd, especially when UNG was disabled. These results show that 5-FU lesions that escape UNG repair activate HR, which promotes cell survival.
Collapse
Affiliation(s)
- Amelia M Huehls
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Catherine J Huntoon
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Poorval M Joshi
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Carly A Baehr
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Jill M Wagner
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Xiaoxiao Wang
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Marietta Y Lee
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| | - Larry M Karnitz
- Department of Molecular Pharmacology and Experimental Therapeutics (A.M.H., C.J.H., P.M.J., C.A.B., J.M.W., L.M.K.) and Division of Oncology Research (C.J.H., J.M.W., L.M.K), Department of Radiation Oncology (L.M.K.), Mayo Clinic, Rochester, Minnesota; and Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York (X.W., M.Y.L.)
| |
Collapse
|
25
|
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
|
26
|
Zdżalik D, Domańska A, Prorok P, Kosicki K, van den Born E, Falnes PØ, Rizzo CJ, Guengerich FP, Tudek B. Differential repair of etheno-DNA adducts by bacterial and human AlkB proteins. DNA Repair (Amst) 2015; 30:1-10. [PMID: 25797601 PMCID: PMC4451939 DOI: 10.1016/j.dnarep.2015.02.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/17/2015] [Accepted: 02/25/2015] [Indexed: 11/16/2022]
Abstract
AlkB proteins are evolutionary conserved Fe(II)/2-oxoglutarate-dependent dioxygenases, which remove alkyl and highly promutagenic etheno(ɛ)-DNA adducts, but their substrate specificity has not been fully determined. We developed a novel assay for the repair of ɛ-adducts by AlkB enzymes using oligodeoxynucleotides with a single lesion and specific DNA glycosylases and AP-endonuclease for identification of the repair products. We compared the repair of three ɛ-adducts, 1,N(6)-ethenoadenine (ɛA), 3,N(4)-ethenocytosine (ɛC) and 1,N(2)-ethenoguanine (1,N(2)-ɛG) by nine bacterial and two human AlkBs, representing four different structural groups defined on the basis of conserved amino acids in the nucleotide recognition lid, engaged in the enzyme binding to the substrate. Two bacterial AlkB proteins, MT-2B (from Mycobacterium tuberculosis) and SC-2B (Streptomyces coelicolor) did not repair these lesions in either double-stranded (ds) or single-stranded (ss) DNA. Three proteins, RE-2A (Rhizobium etli), SA-2B (Streptomyces avermitilis), and XC-2B (Xanthomonas campestris) efficiently removed all three lesions from the DNA substrates. Interestingly, XC-2B and RE-2A are the first AlkB proteins shown to be specialized for ɛ-adducts, since they do not repair methylated bases. Three other proteins, EcAlkB (Escherichia coli), SA-1A, and XC-1B removed ɛA and ɛC from ds and ssDNA but were inactive toward 1,N(2)-ɛG. SC-1A repaired only ɛA with the preference for dsDNA. The human enzyme ALKBH2 repaired all three ɛ-adducts in dsDNA, while only ɛA and ɛC in ssDNA and repair was less efficient in ssDNA. ALKBH3 repaired only ɛC in ssDNA. Altogether, we have shown for the first time that some AlkB proteins, namely ALKBH2, RE-2A, SA-2B and XC-2B can repair 1,N(2)-ɛG and that ALKBH3 removes only ɛC from ssDNA. Our results also suggest that the nucleotide recognition lid is not the sole determinant of the substrate specificity of AlkB proteins.
Collapse
Affiliation(s)
- Daria Zdżalik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Anna Domańska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Paulina Prorok
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Konrad Kosicki
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | | | - Pål Ø Falnes
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Carmelo J Rizzo
- Department of Chemistry, Center in Molecular Toxicology, and Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN, USA
| | - F Peter Guengerich
- Department of Biochemistry, Center in Molecular Toxicology, and Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Barbara Tudek
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
| |
Collapse
|
27
|
Lipid peroxidation product 4-hydroxy-2-nonenal modulates base excision repair in human cells. DNA Repair (Amst) 2014; 22:1-11. [DOI: 10.1016/j.dnarep.2014.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 06/01/2014] [Accepted: 06/06/2014] [Indexed: 11/20/2022]
|
28
|
Talhaoui I, Couve S, Gros L, Ishchenko AA, Matkarimov B, Saparbaev MK. Aberrant repair initiated by mismatch-specific thymine-DNA glycosylases provides a mechanism for the mutational bias observed in CpG islands. Nucleic Acids Res 2014; 42:6300-13. [PMID: 24692658 PMCID: PMC4041421 DOI: 10.1093/nar/gku246] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 03/09/2014] [Accepted: 03/13/2014] [Indexed: 12/13/2022] Open
Abstract
The human thymine-DNA glycosylase (TDG) initiates the base excision repair (BER) pathway to remove spontaneous and induced DNA base damage. It was first biochemically characterized for its ability to remove T mispaired with G in CpG context. TDG is involved in the epigenetic regulation of gene expressions by protecting CpG-rich promoters from de novo DNA methylation. Here we demonstrate that TDG initiates aberrant repair by excising T when it is paired with a damaged adenine residue in DNA duplex. TDG targets the non-damaged DNA strand and efficiently excises T opposite of hypoxanthine (Hx), 1,N(6)-ethenoadenine, 7,8-dihydro-8-oxoadenine and abasic site in TpG/CpX context, where X is a modified residue. In vitro reconstitution of BER with duplex DNA containing Hx•T pair and TDG results in incorporation of cytosine across Hx. Furthermore, analysis of the mutation spectra inferred from single nucleotide polymorphisms in human population revealed a highly biased mutation pattern within CpG islands (CGIs), with enhanced mutation rate at CpA and TpG sites. These findings demonstrate that under experimental conditions used TDG catalyzes sequence context-dependent aberrant removal of thymine, which results in TpG, CpA→CpG mutations, thus providing a plausible mechanism for the putative evolutionary origin of the CGIs in mammalian genomes.
Collapse
Affiliation(s)
- Ibtissam Talhaoui
- Groupe Réparation de l’ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave Roussy, F-94805 Villejuif Cedex, France
| | - Sophie Couve
- Laboratoire de Génétique Oncologique EPHE, INSERM U753, Gustave Roussy, F-94805 Villejuif, France
| | - Laurent Gros
- Groupe Réparation de l’ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave Roussy, F-94805 Villejuif Cedex, France
- AB Science SA, 75008 Paris, France
| | - Alexander A. Ishchenko
- Groupe Réparation de l’ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave Roussy, F-94805 Villejuif Cedex, France
| | - Bakhyt Matkarimov
- Nazarbayev University Research and Innovation System, Astana 010000, Kazakhstan
| | - Murat K. Saparbaev
- Groupe Réparation de l’ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Gustave Roussy, F-94805 Villejuif Cedex, France
| |
Collapse
|
29
|
Ramiro-Merina Á, Ariza RR, Roldán-Arjona T. Molecular characterization of a putative plant homolog of MBD4 DNA glycosylase. DNA Repair (Amst) 2013; 12:890-8. [PMID: 23994068 DOI: 10.1016/j.dnarep.2013.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/02/2013] [Accepted: 08/07/2013] [Indexed: 11/19/2022]
Abstract
Methyl-CpG-binding domain 4 (MBD4) DNA glycosylase is involved in excision of spontaneous deamination products of cytosine and 5-methylcytosine in animals, but it is unknown whether related proteins perform similar functions in plants. We report here the isolation and biochemical characterization of a putative MBD4 homolog from Arabidopsis thaliana, designated as MBD4L (MBD4-like). The plant enzyme lacks the MBD domain present in mammalian MBD4 proteins, but conserves a DNA glycosylase domain with critical residues for substrate recognition and catalysis, and it is more closely related to MBD4 homologs than to other members of the HhH-GPD superfamily. Arabidopsis MBD4L excises uracil and thymine opposite G, and the presence of halogen substituents at C5 of the target base greatly increases its excision efficiency. No significant activity is detected on cytosine derivatives such as 5-methylcytosine or 5-hydroxymethylcytosine. The enzyme binds to the abasic site product generated after excision, which decreases its catalytic turnover in vitro. Both the full-length protein and a N-terminal truncated version retaining the catalytic domain exhibit a preference for a CpG sequence context, where most plant DNA methylation is found. Our results suggest that an important function of Arabidopsis MBD4L is to protect the plant genome from the mutagenic consequences of cytosine and 5-methylcytosine deamination.
Collapse
Affiliation(s)
- Ángel Ramiro-Merina
- Department of Genetics, University of Córdoba/Maimónides Institute for Research in Biomedicine of Córdoba (IMIBIC)/Reina Sofía University Hospital, 14071 Córdoba, Spain
| | | | | |
Collapse
|
30
|
The MBD4 Glu346Lys polymorphism is associated with the risk of cervical cancer in a Chinese population. Int J Gynecol Cancer 2013; 22:1552-6. [PMID: 23027038 DOI: 10.1097/igc.0b013e31826e22e4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE Methyl-CpG binding domain 4 (MBD4) protein functions as a DNA repair enzyme and plays an important role in maintaining genome integrity and carcinogenesis. The polymorphisms in the MBD4 gene may be associated with differences in DNA repair capacity and thereby influence an individual's susceptibility to cervical cancer. To verify this hypothesis, we examined the potential association between the MBD4 Glu346Lys polymorphism (rs140693, G>A) and the risk of cervical cancer in a Chinese population. METHODS We genotyped the MBD4 Glu346Lys polymorphism in 146 cervical cancer cases and 320 healthy female subjects using polymerase chain reaction-based restriction fragment length polymorphism method. Unconditional logistic regression analysis was used to estimate the association between the genotypes and the risk of cervical cancer. RESULTS We observed a significantly decreased risk of cervical cancer associated with the heterozygous Lys/Glu genotype (odds ratio [OR], 0.60; 95% confidence interval [CI], 0.36-0.99; P = 0.046) and the homozygous Glu/Glu genotype (OR, 0.52; 95% CI, 0.30-0.89; P = 0.018), compared with the Lys/Lys homozygotes. Moreover, the reduced cervical cancer risk was more predominant among younger subjects or human papillomavirus-positive individuals carrying Glu/Glu genotypes (OR, 0.33; 95% CI, 0.14-0.78, P = 0.011; and OR, 0.27; 95% CI, 0.09-0.75, P = 0.013, respectively). CONCLUSIONS The MBD4 codon 346 polymorphism may play a role in cervical cancer susceptibility in the Chinese population. Further larger case-control and functional studies are needed to validate these findings.
Collapse
|
31
|
LI W, LIN Y. Identification of Human Methyl-CpG Binding Domain Protein (MBD) 4 as a Substrate of Protein Kinase X*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2011.00430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
32
|
Talhaoui I, Couvé S, Ishchenko AA, Kunz C, Schär P, Saparbaev M. 7,8-Dihydro-8-oxoadenine, a highly mutagenic adduct, is repaired by Escherichia coli and human mismatch-specific uracil/thymine-DNA glycosylases. Nucleic Acids Res 2012. [PMID: 23209024 PMCID: PMC3553953 DOI: 10.1093/nar/gks1149] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hydroxyl radicals predominantly react with the C8 of purines forming 7,8-dihydro-8-oxoguanine (8oxoG) and 7,8-dihydro-8-oxoadenine (8oxoA) adducts, which are highly mutagenic in mammalian cells. The majority of oxidized DNA bases are removed by DNA glycosylases in the base excision repair pathway. Here, we report for the first time that human thymine-DNA glycosylase (hTDG) and Escherichia coli mismatch-specific uracil-DNA glycosylase (MUG) can remove 8oxoA from 8oxoA•T, 8oxoA•G and 8oxoA•C pairs. Comparison of the kinetic parameters of the reaction indicates that full-length hTDG excises 8oxoA, 3,N4-ethenocytosine (εC) and T with similar efficiency (kmax = 0.35, 0.36 and 0.16 min−1, respectively) and is more proficient as compared with its bacterial homologue MUG. The N-terminal domain of the hTDG protein is essential for 8oxoA–DNA glycosylase activity, but not for εC repair. Interestingly, the TDG status had little or no effect on the proliferation rate of mouse embryonic fibroblasts after exposure to γ-irradiation. Nevertheless, using whole cell-free extracts from the DNA glycosylase-deficient murine embryonic fibroblasts and E. coli, we demonstrate that the excision of 8oxoA from 8oxoA•T and 8oxoA•G has an absolute requirement for TDG and MUG, respectively. The data establish that MUG and TDG can counteract the genotoxic effects of 8oxoA residues in vivo.
Collapse
Affiliation(s)
- Ibtissam Talhaoui
- Groupe Réparation de l'ADN, Université Paris Sud, Laboratoire Stabilité Génétique et Oncogenèse CNRS, UMR 8200, Institut de Cancérologie Gustave Roussy, F-94805 Villejuif Cedex, France
| | | | | | | | | | | |
Collapse
|
33
|
Bosshard M, Markkanen E, van Loon B. Base excision repair in physiology and pathology of the central nervous system. Int J Mol Sci 2012. [PMID: 23203191 PMCID: PMC3546685 DOI: 10.3390/ijms131216172] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Relatively low levels of antioxidant enzymes and high oxygen metabolism result in formation of numerous oxidized DNA lesions in the tissues of the central nervous system. Accumulation of damage in the DNA, due to continuous genotoxic stress, has been linked to both aging and the development of various neurodegenerative disorders. Different DNA repair pathways have evolved to successfully act on damaged DNA and prevent genomic instability. The predominant and essential DNA repair pathway for the removal of small DNA base lesions is base excision repair (BER). In this review we will discuss the current knowledge on the involvement of BER proteins in the maintenance of genetic stability in different brain regions and how changes in the levels of these proteins contribute to aging and the onset of neurodegenerative disorders.
Collapse
Affiliation(s)
- Matthias Bosshard
- Institute for Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
| | | | | |
Collapse
|
34
|
Abstract
The base excision repair system is vital to the repair of endogenous and exogenous DNA damage. This pathway is initiated by one of several DNA glycosylases that recognizes and excises specific DNA lesions in a coordinated fashion. Methyl-CpG Domain Protein 4 (MBD4) and Thymine DNA Glycosylase (TDG) are the two major G:T glycosylases that remove thymine generated by the deamination of 5-methylcytosine. Both of these glycosylases also remove a variety of other base lesions, including G:U and preferentially act at CpG sites throughout the genome. Many have questioned the purpose of seemingly redundant glycosylases, but new information has emerged to suggest MBD4 and TDG have diverse biological functions. MBD4 has been closely linked to apoptosis, while TDG has been clearly implicated in transcriptional regulation. This article reviews all of these developments, and discusses the consequences of germline and somatic mutations that lead to non-synonymous amino acid substitutions on MBD4 and TDG protein function. In addition, we report the finding of alternatively spliced variants of MBD4 and TDG and the results of functional studies of a tumor-associated variant of MBD4.
Collapse
|
35
|
da Costa NM, Hautefeuille A, Cros MP, Melendez ME, Waters T, Swann P, Hainaut P, Pinto LFR. Transcriptional regulation of thymine DNA glycosylase (TDG) by the tumor suppressor protein p53. Cell Cycle 2012; 11:4570-8. [PMID: 23165212 DOI: 10.4161/cc.22843] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Thymine DNA glycosylase (TDG) belongs to the superfamily of uracil DNA glycosylases (UDG) and is the first enzyme in the base-excision repair pathway (BER) that removes thymine from G:T mismatches at CpG sites. This glycosylase activity has also been found to be critical for active demethylation of genes involved in embryonic development. Here we show that wild-type p53 transcriptionally regulates TDG expression. Chromatin immunoprecipitation (ChIP) and luciferase assays indicate that wild-type p53 binds to a domain of TDG promoter containing two p53 consensus response elements (p53RE) and activates its transcription. Next, we have used a panel of cell lines with different p53 status to demonstrate that TDG mRNA and protein expression levels are induced in a p53-dependent manner under different conditions. This panel includes isogenic breast and colorectal cancer cell lines with wild-type or inactive p53, esophageal squamous cell carcinoma cell lines lacking p53 or expressing a temperature-sensitive p53 mutant and normal human bronchial epithelial cells. Induction of TDG mRNA expression is accompanied by accumulation of TDG protein in both nucleus and cytoplasm, with nuclear re-localization occurring upon DNA damage in p53-competent, but not -incompetent, cells. These observations suggest a role for p53 activity in TDG nuclear translocation. Overall, our results show that TDG expression is directly regulated by p53, suggesting that loss of p53 function may affect processes mediated by TDG, thus negatively impacting on genetic and epigenetic stability.
Collapse
|
36
|
Moréra S, Grin I, Vigouroux A, Couvé S, Henriot V, Saparbaev M, Ishchenko AA. Biochemical and structural characterization of the glycosylase domain of MBD4 bound to thymine and 5-hydroxymethyuracil-containing DNA. Nucleic Acids Res 2012; 40:9917-26. [PMID: 22848106 PMCID: PMC3479182 DOI: 10.1093/nar/gks714] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Active DNA demethylation in mammals occurs via hydroxylation of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC) by the ten-eleven translocation family of proteins (TETs). 5hmC residues in DNA can be further oxidized by TETs to 5-carboxylcytosines and/or deaminated by the Activation Induced Deaminase/Apolipoprotein B mRNA-editing enzyme complex family proteins to 5-hydromethyluracil (5hmU). Excision and replacement of these intermediates is initiated by DNA glycosylases such as thymine-DNA glycosylase (TDG), methyl-binding domain protein 4 (MBD4) and single-strand specific monofunctional uracil-DNA glycosylase 1 in the base excision repair pathway. Here, we report detailed biochemical and structural characterization of human MBD4 which contains mismatch-specific TDG activity. Full-length as well as catalytic domain (residues 426–580) of human MBD4 (MBD4cat) can remove 5hmU when opposite to G with good efficiency. Here, we also report six crystal structures of human MBD4cat: an unliganded form and five binary complexes with duplex DNA containing a T•G, 5hmU•G or AP•G (apurinic/apyrimidinic) mismatch at the target base pair. These structures reveal that MBD4cat uses a base flipping mechanism to specifically recognize thymine and 5hmU. The recognition mechanism of flipped-out 5hmU bases in MBD4cat active site supports the potential role of MBD4, together with TDG, in maintenance of genome stability and active DNA demethylation in mammals.
Collapse
Affiliation(s)
- Solange Moréra
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, Gif-sur-Yvette Cedex, F-91198, France.
| | | | | | | | | | | | | |
Collapse
|
37
|
Hashimoto H, Zhang X, Cheng X. Excision of thymine and 5-hydroxymethyluracil by the MBD4 DNA glycosylase domain: structural basis and implications for active DNA demethylation. Nucleic Acids Res 2012; 40:8276-84. [PMID: 22740654 PMCID: PMC3458566 DOI: 10.1093/nar/gks628] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The mammalian DNA glycosylase—methyl-CpG binding domain protein 4 (MBD4)—is involved in active DNA demethylation via the base excision repair pathway. MBD4 contains an N-terminal MBD and a C-terminal DNA glycosylase domain. MBD4 can excise the mismatched base paired with a guanine (G:X), where X is uracil, thymine or 5-hydroxymethyluracil (5hmU). These are, respectively, the deamination products of cytosine, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). Here, we present three structures of the MBD4 C-terminal glycosylase domain (wild-type and its catalytic mutant D534N), in complex with DNA containing a G:T or G:5hmU mismatch. MBD4 flips the target nucleotide from the double-stranded DNA. The catalytic mutant D534N captures the intact target nucleotide in the active site binding pocket. MBD4 specifically recognizes the Watson–Crick polar edge of thymine or 5hmU via the O2, N3 and O4 atoms, thus restricting its activity to thymine/uracil-based modifications while excluding cytosine and its derivatives. The wild-type enzyme cleaves the N-glycosidic bond, leaving the ribose ring in the flipped state, while the cleaved base is released. Unexpectedly, the C1′ of the sugar has yet to be hydrolyzed and appears to form a stable intermediate with one of the side chain carboxyl oxygen atoms of D534, via either electrostatic or covalent interaction, suggesting a different catalytic mechanism from those of other DNA glycosylases.
Collapse
Affiliation(s)
- Hideharu Hashimoto
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
| | | | | |
Collapse
|
38
|
Checkpoint signaling, base excision repair, and PARP promote survival of colon cancer cells treated with 5-fluorodeoxyuridine but not 5-fluorouracil. PLoS One 2011; 6:e28862. [PMID: 22194930 PMCID: PMC3240632 DOI: 10.1371/journal.pone.0028862] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 11/16/2011] [Indexed: 12/19/2022] Open
Abstract
The fluoropyrimidines 5-fluorouracil (5-FU) and FdUrd (5-fluorodeoxyuridine; floxuridine) are the backbone of chemotherapy regimens for colon cancer and other tumors. Despite their widespread use, it remains unclear how these agents kill tumor cells. Here, we have analyzed the checkpoint and DNA repair pathways that affect colon tumor responses to 5-FU and FdUrd. These studies demonstrate that both FdUrd and 5-FU activate the ATR and ATM checkpoint signaling pathways, indicating that they cause genotoxic damage. Notably, however, depletion of ATM or ATR does not sensitize colon cancer cells to 5-FU, whereas these checkpoint pathways promote the survival of cells treated with FdUrd, suggesting that FdUrd exerts cytotoxicity by disrupting DNA replication and/or inducing DNA damage, whereas 5-FU does not. We also found that disabling the base excision (BER) repair pathway by depleting XRCC1 or APE1 sensitized colon cancer cells to FdUrd but not 5-FU. Consistent with a role for the BER pathway, we show that small molecule poly(ADP-ribose) polymerase 1/2 (PARP) inhibitors, AZD2281 and ABT-888, remarkably sensitized both mismatch repair (MMR)-proficient and -deficient colon cancer cell lines to FdUrd but not to 5-FU. Taken together, these studies demonstrate that the roles of genotoxin-induced checkpoint signaling and DNA repair differ significantly for these agents and also suggest a novel approach to colon cancer therapy in which FdUrd is combined with a small molecule PARP inhibitor.
Collapse
|
39
|
DNA glycosylases: in DNA repair and beyond. Chromosoma 2011; 121:1-20. [PMID: 22048164 PMCID: PMC3260424 DOI: 10.1007/s00412-011-0347-4] [Citation(s) in RCA: 254] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/10/2011] [Accepted: 10/11/2011] [Indexed: 12/20/2022]
Abstract
The base excision repair machinery protects DNA in cells from the damaging effects of oxidation, alkylation, and deamination; it is specialized to fix single-base damage in the form of small chemical modifications. Base modifications can be mutagenic and/or cytotoxic, depending on how they interfere with the template function of the DNA during replication and transcription. DNA glycosylases play a key role in the elimination of such DNA lesions; they recognize and excise damaged bases, thereby initiating a repair process that restores the regular DNA structure with high accuracy. All glycosylases share a common mode of action for damage recognition; they flip bases out of the DNA helix into a selective active site pocket, the architecture of which permits a sensitive detection of even minor base irregularities. Within the past few years, it has become clear that nature has exploited this ability to read the chemical structure of DNA bases for purposes other than canonical DNA repair. DNA glycosylases have been brought into context with molecular processes relating to innate and adaptive immunity as well as to the control of DNA methylation and epigenetic stability. Here, we summarize the key structural and mechanistic features of DNA glycosylases with a special focus on the mammalian enzymes, and then review the evidence for the newly emerging biological functions beyond the protection of genome integrity.
Collapse
|
40
|
Wisniewska-Jarosinska M, Sliwinski T, Kasznicki J, Kaczmarczyk D, Krupa R, Bloch K, Drzewoski J, Chojnacki J, Blasiak J, Morawiec-Sztandera A. Cytotoxicity and genotoxicity of capecitabine in head and neck cancer and normal cells. Mol Biol Rep 2011; 38:3679-88. [PMID: 21107724 PMCID: PMC3115142 DOI: 10.1007/s11033-010-0482-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 11/09/2010] [Indexed: 11/29/2022]
Abstract
The interaction between a chemical and a cell may strongly depend on whether this cell is normal or pathological. Side effects of anticancer drugs may sometimes overcome their benefit action, so it is important to investigate their effect in both the target and normal cells. Capecitabine (Xeloda, CAP), a prodrug of 5-fluorouracil, is mainly used in colon cancer, but little is known about its action in head and neck cancer. We compared the cyto- and genotoxicity of CAP in head and neck HTB-43 cells and normal human lymphocytes by comet assay and flow cytometry. CAP at concentration up to 50 μM significantly decreased the viability of the cancer cells, whereas it did not affect normal lymphocytes. The drug did not interact with isolated plasmid DNA, but it damaged DNA in both cancer and normal cells. However, the extent of the damage in the former was much higher than in the latter. CAP induced apoptosis in the cancer cells, but not in normal lymphocytes. Pre-treatment of the cells with the nitrone spin traps α-(4-pyridil-1-oxide)-N-tert-butylnitrone and N-tert-butyl-α-phenylnitrone decreased the extent of CAP induced DNA damage, suggesting that free radicals may be involved in the formation of DNA lesions induced by CAP. The drug evoked an increase in the G0/G1 cell population accompanied by a decrease in the S cell population. CAP may evoke a pronounced cyto- and genotoxic effects in head and neck cancer cells, whereas it may or may not induce such effects in normal cells to far lesser extent.
Collapse
Affiliation(s)
| | - Tomasz Sliwinski
- Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland
| | - Jacek Kasznicki
- Department of Clinical Pharmacology, Medical University of Lodz, 95-100 Zgierz, Poland
| | - Dariusz Kaczmarczyk
- Department of Head and Neck Cancer, Medical University of Lodz, 93-509 Lodz, Poland
| | - Renata Krupa
- Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland
| | - Karolina Bloch
- Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland
| | - Jozef Drzewoski
- Department of Clinical Pharmacology, Medical University of Lodz, 95-100 Zgierz, Poland
| | - Jan Chojnacki
- Department of Gastroenterology and Internal Medicine, Medical University of Lodz, 90-647 Lodz, Poland
| | - Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland
| | | |
Collapse
|
41
|
Cortellino S, Xu J, Sannai M, Moore R, Caretti E, Cigliano A, Le Coz M, Devarajan K, Wessels A, Soprano D, Abramowitz LK, Bartolomei MS, Rambow F, Bassi MR, Bruno T, Fanciulli M, Renner C, Klein-Szanto AJ, Matsumoto Y, Kobi D, Davidson I, Alberti C, Larue L, Bellacosa A. Thymine DNA glycosylase is essential for active DNA demethylation by linked deamination-base excision repair. Cell 2011; 146:67-79. [PMID: 21722948 DOI: 10.1016/j.cell.2011.06.020] [Citation(s) in RCA: 595] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 05/17/2011] [Accepted: 06/12/2011] [Indexed: 01/19/2023]
Abstract
DNA methylation is a major epigenetic mechanism for gene silencing. Whereas methyltransferases mediate cytosine methylation, it is less clear how unmethylated regions in mammalian genomes are protected from de novo methylation and whether an active demethylating activity is involved. Here, we show that either knockout or catalytic inactivation of the DNA repair enzyme thymine DNA glycosylase (TDG) leads to embryonic lethality in mice. TDG is necessary for recruiting p300 to retinoic acid (RA)-regulated promoters, protection of CpG islands from hypermethylation, and active demethylation of tissue-specific developmentally and hormonally regulated promoters and enhancers. TDG interacts with the deaminase AID and the damage response protein GADD45a. These findings highlight a dual role for TDG in promoting proper epigenetic states during development and suggest a two-step mechanism for DNA demethylation in mammals, whereby 5-methylcytosine and 5-hydroxymethylcytosine are first deaminated by AID to thymine and 5-hydroxymethyluracil, respectively, followed by TDG-mediated thymine and 5-hydroxymethyluracil excision repair.
Collapse
Affiliation(s)
- Salvatore Cortellino
- Cancer Biology Program and Epigenetics and Progenitor Cells Keystone Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Law JA, Jacobsen SE. Establishing, maintaining and modifying DNA methylation patterns in plants and animals. Nat Rev Genet 2011; 11:204-20. [PMID: 20142834 DOI: 10.1038/nrg2719] [Citation(s) in RCA: 2467] [Impact Index Per Article: 189.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cytosine DNA methylation is a stable epigenetic mark that is crucial for diverse biological processes, including gene and transposon silencing, imprinting and X chromosome inactivation. Recent findings in plants and animals have greatly increased our understanding of the pathways used to accurately target, maintain and modify patterns of DNA methylation and have revealed unanticipated mechanistic similarities between these organisms. Key roles have emerged for small RNAs, proteins with domains that bind methylated DNA and DNA glycosylases in these processes. Drawing on insights from both plants and animals should deepen our understanding of the regulation and biological significance of DNA methylation.
Collapse
Affiliation(s)
- Julie A Law
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 90095-1606, USA
| | | |
Collapse
|
43
|
Hang B. Formation and repair of tobacco carcinogen-derived bulky DNA adducts. J Nucleic Acids 2010; 2010:709521. [PMID: 21234336 PMCID: PMC3017938 DOI: 10.4061/2010/709521] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/16/2010] [Accepted: 09/17/2010] [Indexed: 01/08/2023] Open
Abstract
DNA adducts play a central role in chemical carcinogenesis. The analysis of formation and repair of smoking-related DNA adducts remains particularly challenging as both smokers and nonsmokers exposed to smoke are repetitively under attack from complex mixtures of carcinogens such as polycyclic aromatic hydrocarbons and N-nitrosamines. The bulky DNA adducts, which usually have complex structure, are particularly important because of their biological relevance. Several known cellular DNA repair pathways have been known to operate in human cells on specific types of bulky DNA adducts, for example, nucleotide excision repair, base excision repair, and direct reversal involving O6-alkylguanine DNA alkyltransferase or AlkB homologs. Understanding the mechanisms of adduct formation and repair processes is critical for the assessment of cancer risk resulting from exposure to cigarette smoke, and ultimately for developing strategies of cancer prevention. This paper highlights the recent progress made in the areas concerning formation and repair of bulky DNA adducts in the context of tobacco carcinogen-associated genotoxic and carcinogenic effects.
Collapse
Affiliation(s)
- Bo Hang
- Life Sciences Division, Department of Cancer and DNA Damage Responses, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| |
Collapse
|
44
|
Bertoni C, Rustagi A, Rando TA. Enhanced gene repair mediated by methyl-CpG-modified single-stranded oligonucleotides. Nucleic Acids Res 2010; 37:7468-82. [PMID: 19854937 PMCID: PMC2794159 DOI: 10.1093/nar/gkp757] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gene editing mediated by oligonucleotides has been shown to induce stable single base alterations in genomic DNA in both prokaryotic and eukaryotic organisms. However, the low frequencies of gene repair have limited its applicability for both basic manipulation of genomic sequences and for the development of therapeutic approaches for genetic disorders. Here, we show that single-stranded oligodeoxynucleotides (ssODNs) containing a methyl-CpG modification and capable of binding to the methyl-CpG binding domain protein 4 (MBD4) are able to induce >10-fold higher levels of gene correction than ssODNs lacking the specific modification. Correction was stably inherited through cell division and was confirmed at the protein, transcript and genomic levels. Downregulation of MBD4 expression using RNAi prevented the enhancement of gene correction efficacy obtained using the methyl-CpG-modified ssODN, demonstrating the specificity of the repair mechanism being recruited. Our data demonstrate that efficient manipulation of genomic targets can be achieved and controlled by the type of ssODN used and by modulation of the repair mechanism involved in the correction process. This new generation of ssODNs represents an important technological advance that is likely to have an impact on multiple applications, especially for gene therapy where permanent correction of the genetic defect has clear advantages over viral and other nonviral approaches currently being tested.
Collapse
Affiliation(s)
- Carmen Bertoni
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | | | | |
Collapse
|
45
|
Zhao H, Du W, Wang D, Gu D, Xue F, Ge J, Sui T, Yang R. Single nucleotide polymorphism in the methyl-CpG binding domain 4 Gene and the risk for immune thrombocytopenic purpura in Chinese population. Platelets 2010; 21:132-6. [DOI: 10.3109/09537100903474365] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
46
|
Micronucleus Occurrence Related to Base Excision Repair Gene Polymorphisms in Chinese Workers Occupationally Exposed to Vinyl Chloride Monomer. J Occup Environ Med 2009; 51:578-85. [DOI: 10.1097/jom.0b013e3181990d19] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
47
|
Baute J, Depicker A. Base excision repair and its role in maintaining genome stability. Crit Rev Biochem Mol Biol 2008; 43:239-76. [PMID: 18756381 DOI: 10.1080/10409230802309905] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
For all living organisms, genome stability is important, but is also under constant threat because various environmental and endogenous damaging agents can modify the structural properties of DNA bases. As a defense, organisms have developed different DNA repair pathways. Base excision repair (BER) is the predominant pathway for coping with a broad range of small lesions resulting from oxidation, alkylation, and deamination, which modify individual bases without large effect on the double helix structure. As, in mammalian cells, this damage is estimated to account daily for 10(4) events per cell, the need for BER pathways is unquestionable. The damage-specific removal is carried out by a considerable group of enzymes, designated as DNA glycosylases. Each DNA glycosylase has its unique specificity and many of them are ubiquitous in microorganisms, mammals, and plants. Here, we review the importance of the BER pathway and we focus on the different roles of DNA glycosylases in various organisms.
Collapse
Affiliation(s)
- Joke Baute
- Department of Plant Systems Biology, Flanders Institute for Biotechnology, Gent, Belgium
| | | |
Collapse
|
48
|
MBD4-mediated glycosylase activity on a chromatin template is enhanced by acetylation. Mol Cell Biol 2008; 28:4734-44. [PMID: 18519584 DOI: 10.1128/mcb.00588-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of the MBD4 glycosylase to excise a mismatched base from DNA has been assessed in vitro using DNA substrates with different extents of cytosine methylation, in the presence or absence of reconstituted nucleosomes. Despite the enhanced ability of MBD4 to bind to methylated cytosines, the efficiency of its glycosylase activity on T/G mismatches was slightly dependent on the extent of methylation of the DNA substrate. The reduction in activity caused by competitor DNA was likewise unaffected by the methylation status of the substrate or the competitor. Our results also show that MBD4 efficiently processed T/G mismatches within the nucleosome. Furthermore, the glycolytic activity of the enzyme was not affected by the positioning of the mismatch within the nucleosome. However, histone hyperacetylation facilitated the efficiency with which the bases were excised from the nucleosome templates, irrespective of the position of the mismatch relative to the pseudodyad axis of symmetry of the nucleosome.
Collapse
|
49
|
Abstract
Chromatin-modifying proteins mold the genome into areas that are accessible for transcriptional activity and areas that are transcriptionally silent. This epigenetic gene regulation allows for different transcriptional programs to be conducted in different cell types at different timepoints-despite the fact that all cells in the organism contain the same genetic information. A large amount of data gathered over the last decades has demonstrated that deregulation of chromatin-modifying proteins is etiologically involved in the development and progression of cancer. Here we discuss how epigenetic alterations influence cancer development and review known cancer-associated alterations in chromatin-modifying proteins.
Collapse
Affiliation(s)
- Cathrine K Fog
- Biotech Research & Innovation Centre and Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, DK- 2200 Copenhagen Denmark
| | | | | |
Collapse
|
50
|
Abdel-Rahman WM, Knuutila S, Peltomäki P, Harrison DJ, Bader SA. Truncation of MBD4 predisposes to reciprocal chromosomal translocations and alters the response to therapeutic agents in colon cancer cells. DNA Repair (Amst) 2007; 7:321-8. [PMID: 18162445 DOI: 10.1016/j.dnarep.2007.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 10/18/2007] [Accepted: 11/06/2007] [Indexed: 01/27/2023]
Abstract
We previously identified a novel genomic instability phenotype of multiple reciprocal chromosomal translocations in a MLH1-defective, microsatellite unstable (MSI) colon cancer cell line (HCA7) and, further, showed that it was unlikely to be directly caused by the mismatch repair (MMR) defect in this cell line. To gain insight into the molecular basis to this novel translocation phenotype, we examined coding and splice-site nucleotide repeat tracts in DNA repair genes for mutations by direct sequencing together with RT-PCR expression analysis of the associated transcript. The material was a selected panel of 8 MSI cell lines including HCA7. A strong candidate identified through this approach was MBD4 as it showed a homozygous truncating mutation associated with substantial loss of the transcript in HCA7 not seen in the other lines. In previous published studies, heterozygous MBD4 mutations were observed in up to 89% of sporadic MSI microdissected colon tumor foci. Using MFISH, we show that over-expression of the truncated MBD4 (+MBD4(tru)) in DLD1, a MSH6 defective, MSI human colon carcinoma cell line predisposed these cells to acquire structural chromosomal rearrangements including multiple reciprocal translocations after irradiation, reminiscent of those seen in HCA7. We also show that over-expression of MBD4(tru) in DLD1 alters the colony survival after exposure to cisplatin or etoposide. These data suggest a wide role for MBD4 in DNA damage response and maintaining chromosomal stability.
Collapse
|