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Fahrer J, Christmann M. DNA Alkylation Damage by Nitrosamines and Relevant DNA Repair Pathways. Int J Mol Sci 2023; 24:ijms24054684. [PMID: 36902118 PMCID: PMC10003415 DOI: 10.3390/ijms24054684] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/04/2023] Open
Abstract
Nitrosamines occur widespread in food, drinking water, cosmetics, as well as tobacco smoke and can arise endogenously. More recently, nitrosamines have been detected as impurities in various drugs. This is of particular concern as nitrosamines are alkylating agents that are genotoxic and carcinogenic. We first summarize the current knowledge on the different sources and chemical nature of alkylating agents with a focus on relevant nitrosamines. Subsequently, we present the major DNA alkylation adducts induced by nitrosamines upon their metabolic activation by CYP450 monooxygenases. We then describe the DNA repair pathways engaged by the various DNA alkylation adducts, which include base excision repair, direct damage reversal by MGMT and ALKBH, as well as nucleotide excision repair. Their roles in the protection against the genotoxic and carcinogenic effects of nitrosamines are highlighted. Finally, we address DNA translesion synthesis as a DNA damage tolerance mechanism relevant to DNA alkylation adducts.
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Affiliation(s)
- Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, RPTU Kaiserslautern-Landau, Erwin-Schrödinger Strasse 52, D-67663 Kaiserslautern, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany
- Correspondence: (J.F.); (M.C.); Tel.: +496312052974 (J.F.); Tel: +496131179066 (M.C.)
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Chen H, Zhou L, Li J, Hu K. ALKBH family members as novel biomarkers and prognostic factors in human breast cancer. Aging (Albany NY) 2022; 14. [PMID: 35980268 DOI: 10.18632/aging.204231] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/27/2022] [Indexed: 12/11/2022]
Abstract
Breast cancer is the most common lethal carcinoma worldwide and better targeted therapies are still worthy of exploration, having had some great successes already. Abnormal expression of ALKBH members were found in various cancers, and the roles played by it were the focus of attention. The ALKBH gene family encodes nine homologous enzymes (ALKBH1-8 and FTO) to repair DNA or RNA depending on Fe2+ and α-ketoglutarate (α-KG), which is related to carcinogenesis. In this study, we applied several databases to explore the roles of ALKBHs in breast cancer. We found that ALKBH members were abnormal expression in breast cancer and associated with tumor stage and subclasses. Higher alteration rates of ALKBH family were found in breast cancer. Function enrichment revealed that several cancer-associated signal pathways were related to ALKBH family such as PI3K-Akt signaling pathway and axon guidance. Infiltration of immune cells (Eosinophiles, NK CD56bright cells, mast cells, T helper cells and so on) were strongly related to ALKBHs. Moreover, we further found that there was strong correlation between ALKBH7 and higher age, later T stage, ER/PR positive and post-menopause of breast cancer patients, and patients with higher ALKBH7 expression had shorter overall survival (OS) and post progression survival (PPS). In conclusion, our findings may provide novel insights into ALKBH-targeted therapy for breast cancer patients, and ALKBH7 may be a potential prognostic biomarker.
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Shen H, Luo B, Wang Y, Li J, Hu Z, Xie Q, Wu T, Chen G. Genome-Wide Identification, Classification and Expression Analysis of m 6A Gene Family in Solanum lycopersicum. Int J Mol Sci 2022; 23:4522. [PMID: 35562913 DOI: 10.3390/ijms23094522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 02/06/2023] Open
Abstract
Advanced knowledge of messenger RNA (mRNA) N6-methyladenosine (m6A) and DNA N6-methyldeoxyadenosine (6 mA) redefine our understanding of these epigenetic modifications. Both m6A and 6mA carry important information for gene regulation, and the corresponding catalytic enzymes sometimes belong to the same gene family and need to be distinguished. However, a comprehensive analysis of the m6A gene family in tomato remains obscure. Here, 24 putative m6A genes and their family genes in tomato were identified and renamed according to BLASTP and phylogenetic analysis. Chromosomal location, synteny, phylogenetic, and structural analyses were performed, unravelling distinct evolutionary relationships between the MT-A70, ALKBH, and YTH protein families, respectively. Most of the 24 genes had extensive tissue expression, and 9 genes could be clustered in a similar expression trend. Besides, SlYTH1 and SlYTH3A showed a different expression pattern in leaf and fruit development. Additionally, qPCR data revealed the expression variation under multiple abiotic stresses, and LC-MS/MS determination exhibited that the cold stress decreased the level of N6 2′-O dimethyladenosine (m6Am). Notably, the orthologs of newly identified single-strand DNA (ssDNA) 6mA writer–eraser–reader also existed in the tomato genome. Our study provides comprehensive information on m6A components and their family proteins in tomato and will facilitate further functional analysis of the tomato N6-methyladenosine modification genes.
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Kostyusheva A, Brezgin S, Glebe D, Kostyushev D, Chulanov V. Host-cell interactions in HBV infection and pathogenesis: the emerging role of m6A modification. Emerg Microbes Infect 2021; 10:2264-2275. [PMID: 34767497 PMCID: PMC8648018 DOI: 10.1080/22221751.2021.2006580] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 12/28/2022]
Abstract
Hepatitis B virus (HBV) is a DNA virus with a complex life cycle that includes a reverse transcription step. HBV is poorly sensed by the immune system and frequently establishes persistent infection that can cause chronic infection, the leading cause of liver cancer and cirrhosis worldwide. Recent mounting evidence has indicated the growing importance of RNA methylation (m6A modification) in viral replication, immune escape, and carcinogenesis. The value of m6A RNA modification for the prediction and clinical management of chronic HBV infection remains to be assessed. However, a number of studies indicate the important role of m6A-marked transcripts and factors of m6A machinery in managing HBV-related pathologies. In this review, we discuss the fundamental and potential clinical impact of m6A modifications on HBV infection and pathogenesis, as well as highlight the important molecular techniques and tools that can be used for studying RNA m6A methylome.
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Affiliation(s)
- Anastasiya Kostyusheva
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, Moscow, Russia
| | - Sergey Brezgin
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, Moscow, Russia
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, Sochi, Russia
| | - Dieter Glebe
- National Reference Center for Hepatitis B Viruses and Hepatitis D Viruses, Institute of Medical Virology, Justus Liebig University of Giessen, Giessen, Germany
| | - Dmitry Kostyushev
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, Moscow, Russia
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, Sochi, Russia
| | - Vladimir Chulanov
- National Medical Research Center of Tuberculosis and Infectious Diseases, Ministry of Health, Moscow, Russia
- Scientific Center for Genetics and Life Sciences, Division of Biotechnology, Sirius University of Science and Technology, Sochi, Russia
- Department of Infectious Diseases, Sechenov University, Moscow, Russia
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Alvarado-Marchena L, Marquez-Molins J, Martinez-Perez M, Aparicio F, Pallás V. Mapping of Functional Subdomains in the atALKBH9B m 6A-Demethylase Required for Its Binding to the Viral RNA and to the Coat Protein of Alfalfa Mosaic Virus. Front Plant Sci 2021; 12:701683. [PMID: 34290728 PMCID: PMC8287571 DOI: 10.3389/fpls.2021.701683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/09/2021] [Indexed: 06/01/2023]
Abstract
N 6-methyladenosine (m6A) modification is a dynamically regulated RNA modification that impacts many cellular processes and pathways. This epitranscriptomic methylation relies on the participation of RNA methyltransferases (referred to as "writers") and demethylases (referred to as "erasers"), respectively. We previously demonstrated that the Arabidopsis thaliana protein atALKBH9B showed m6A-demethylase activity and interacted with the coat protein (CP) of alfalfa mosaic virus (AMV), causing a profound impact on the viral infection cycle. To dissect the functional activity of atALKBH9B in AMV infection, we performed a protein-mapping analysis to identify the putative domains required for regulating this process. In this context, the mutational analysis of the protein revealed that the residues between 427 and 467 positions are critical for in vitro binding to the AMV RNA. The atALKBH9B amino acid sequence showed intrinsically disordered regions (IDRs) located at the N-terminal part delimiting the internal AlkB-like domain and at the C-terminal part. We identified an RNA binding domain containing an RGxxxRGG motif that overlaps with the C-terminal IDR. Moreover, bimolecular fluorescent experiments allowed us to determine that residues located between 387 and 427 are critical for the interaction with the AMV CP, which should be critical for modulating the viral infection process. Finally, we observed that atALKBH9B deletions of either N-terminal 20 residues or the C-terminal's last 40 amino acids impede their accumulation in siRNA bodies. The involvement of the regions responsible for RNA and viral CP binding and those required for its localization in stress granules in the viral cycle is discussed.
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Huong TT, Ngoc LNT, Kang H. Functional Characterization of a Putative RNA Demethylase ALKBH6 in Arabidopsis Growth and Abiotic Stress Responses. Int J Mol Sci 2020; 21:ijms21186707. [PMID: 32933187 PMCID: PMC7555452 DOI: 10.3390/ijms21186707] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 12/15/2022] Open
Abstract
RNA methylation and demethylation, which is mediated by RNA methyltransferases (referred to as “writers”) and demethylases (referred to as “erasers”), respectively, are emerging as a key regulatory process in plant development and stress responses. Although several studies have shown that AlkB homolog (ALKBH) proteins are potential RNA demethylases, the function of most ALKBHs is yet to be determined. The Arabidopsis thaliana genome contains thirteen genes encoding ALKBH proteins, the functions of which are largely unknown. In this study, we characterized the function of a potential eraser protein, ALKBH6 (At4g20350), during seed germination and seedling growth in Arabidopsis under abiotic stresses. The seeds of T-DNA insertion alkbh6 knockdown mutants germinated faster than the wild-type seeds under cold, salt, or abscisic acid (ABA) treatment conditions but not under dehydration stress conditions. Although no differences in seedling and root growth were observed between the alkbh6 mutant and wild-type under normal conditions, the alkbh6 mutant showed a much lower survival rate than the wild-type under salt, drought, or heat stress. Cotyledon greening of the alkbh6 mutants was much higher than that of the wild-type upon ABA application. Moreover, the transcript levels of ABA signaling-related genes, including ABI3 and ABI4, were down-regulated in the alkbh6 mutant compared to wild-type plants. Importantly, the ALKBH6 protein had an ability to bind to both m6A-labeled and m5C-labeled RNAs. Collectively, these results indicate that the potential eraser ALKBH6 plays important roles in seed germination, seedling growth, and survival of Arabidopsis under abiotic stresses.
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Affiliation(s)
- Trinh Thi Huong
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.H.); (L.N.T.N.)
- The Western Highlands Agriculture and Forestry Science Institute, Buon Ma Thuot, DakLak 63000, Vietnam
| | - Le Nguyen Tieu Ngoc
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.H.); (L.N.T.N.)
- Faculty of Forestry Agriculture, Tay Nguyen University, Buon Ma Thuot, DakLak 63000, Vietnam
| | - Hunseung Kang
- Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea; (T.T.H.); (L.N.T.N.)
- Correspondence: ; Tel.: +82-(62)-530-2181
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Baldwin MR, Admiraal SJ, O'Brien PJ. Transient kinetic analysis of oxidative dealkylation by the direct reversal DNA repair enzyme AlkB. J Biol Chem 2020; 295:7317-7326. [PMID: 32284330 PMCID: PMC7247310 DOI: 10.1074/jbc.ra120.013517] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/10/2020] [Indexed: 11/06/2022] Open
Abstract
AlkB is a bacterial Fe(II)- and 2-oxoglutarate-dependent dioxygenase that repairs a wide range of alkylated nucleobases in DNA and RNA as part of the adaptive response to exogenous nucleic acid-alkylating agents. Although there has been longstanding interest in the structure and specificity of Escherichia coli AlkB and its homologs, difficulties in assaying their repair activities have limited our understanding of their substrate specificities and kinetic mechanisms. Here, we used quantitative kinetic approaches to determine the transient kinetics of recognition and repair of alkylated DNA by AlkB. These experiments revealed that AlkB is a much faster alkylation repair enzyme than previously reported and that it is significantly faster than DNA repair glycosylases that recognize and excise some of the same base lesions. We observed that whereas 1,N6-ethenoadenine can be repaired by AlkB with similar efficiencies in both single- and double-stranded DNA, 1-methyladenine is preferentially repaired in single-stranded DNA. Our results lay the groundwork for future studies of AlkB and its human homologs ALKBH2 and ALKBH3.
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Affiliation(s)
- Michael R Baldwin
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| | - Suzanne J Admiraal
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600
| | - Patrick J O'Brien
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0600.
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Marcinkowski M, Pilžys T, Garbicz D, Steciuk J, Zugaj D, Mielecki D, Sarnowski TJ, Grzesiuk E. Human and Arabidopsis alpha-ketoglutarate-dependent dioxygenase homolog proteins-New players in important regulatory processes. IUBMB Life 2020; 72:1126-1144. [PMID: 32207231 DOI: 10.1002/iub.2276] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/20/2020] [Accepted: 03/08/2020] [Indexed: 12/31/2022]
Abstract
The family of AlkB homolog (ALKBH) proteins, the homologs of Escherichia coli AlkB 2-oxoglutarate (2OG), and Fe(II)-dependent dioxygenase are involved in a number of important regulatory processes in eukaryotic cells including repair of alkylation lesions in DNA, RNA, and nucleoprotein complexes. There are nine human and thirteen Arabidopsis thaliana ALKBH proteins described, which exhibit diversified functions. Among them, human ALKBH5 and FaT mass and Obesity-associated (FTO) protein and Arabidopsis ALKBH9B and ALKBH10B have been recognized as N6 methyladenine (N6 meA) demethylases, the most abundant posttranscriptional modification in mRNA. The FTO protein is reported to be associated with obesity and type 2 diabetes, and involved in multiple other processes, while ALKBH5 is induced by hypoxia. Arabidopsis ALKBH9B is an N6 meA demethylase influencing plant susceptibility to viral infections via m6 A/A ratio control in viral RNA. ALKBH10B has been discovered to be a functional Arabidopsis homolog of FTO; thus, it is also an RNA N6 meA demethylase involved in plant flowering and several other regulatory processes including control of metabolism. High-throughput mass spectrometry showed multiple sites of human ALKBH phosphorylation. In the case of FTO, the type of modified residue decides about the further processing of the protein. This modification may result in subsequent protein ubiquitination and proteolysis, or in the blocking of these processes. However, the impact of phosphorylation on the other ALKBH function and their downstream pathways remains nearly unexplored in both human and Arabidopsis. Therefore, the investigation of evolutionarily conserved functions of ALKBH proteins and their regulatory impact on important cellular processes is clearly called for.
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Affiliation(s)
- Michał Marcinkowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Tomaš Pilžys
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Damian Garbicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Jaroslaw Steciuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Zugaj
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Damian Mielecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz J Sarnowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Elżbieta Grzesiuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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Anindya R. Single-stranded DNA damage: Protecting the single-stranded DNA from chemical attack. DNA Repair (Amst) 2020; 87:102804. [PMID: 31981739 DOI: 10.1016/j.dnarep.2020.102804] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 01/18/2020] [Accepted: 01/18/2020] [Indexed: 01/08/2023]
Abstract
Cellular processes, such as DNA replication, recombination and transcription, require DNA strands separation and single-stranded DNA is formation. The single-stranded DNA is promptly wrapped by human single-stranded DNA binding proteins, replication protein A (RPA) complex. RPA binding not only prevent nuclease degradation and annealing, but it also coordinates cell-cycle checkpoint activation and DNA repair. However, RPA binding offers little protection against the chemical modification of DNA bases. This review focuses on the type of DNA base damage that occurs in single-stranded DNA and how the damage is rectified in human cells. The discovery of DNA repair proteins, such as ALKBH3, AGT, UNG2, NEIL3, being able to repair the damaged base in the single-stranded DNA, renewed the interest to study single-stranded DNA repair. These mechanistically different proteins work independently from each other with the overarching goal of increasing fidelity of recombination and promoting error-free replication.
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Bhat SS, Bielewicz D, Jarmolowski A, Szweykowska-Kulinska Z. N⁶-methyladenosine (m⁶A): Revisiting the Old with Focus on New, an Arabidopsis thaliana Centered Review. Genes (Basel) 2018; 9:E596. [PMID: 30513695 DOI: 10.3390/genes9120596] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 01/24/2023] Open
Abstract
N6-methyladenosine (m6A) is known to occur in plant and animal messenger RNAs (mRNAs) since the 1970s. However, the scope and function of this modification remained un-explored till very recently. Since the beginning of this decade, owing to major technological breakthroughs, the interest in m6A has peaked again. Similar to animal mRNAs, plant mRNAs are also m6A methylated, within a specific sequence motif which is conserved across these kingdoms. m6A has been found to be pivotal for plant development and necessary for processes ranging from seed germination to floral development. A wide range of proteins involved in methylation of adenosine have been identified alongside proteins that remove or identify m6A. This review aims to put together the current knowledge regarding m6A in Arabidopsis thaliana.
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Ougland R, Rognes T, Klungland A, Larsen E. Non-homologous functions of the AlkB homologs. J Mol Cell Biol 2015; 7:494-504. [PMID: 26003568 DOI: 10.1093/jmcb/mjv029] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/26/2015] [Indexed: 12/22/2022] Open
Abstract
The DNA repair enzyme AlkB was identified in E. coli more than three decades ago. Since then, nine mammalian homologs, all members of the superfamily of alpha-ketoglutarate and Fe(II)-dependent dioxygenases, have been identified (designated ALKBH1-8 and FTO). While E. coli AlkB serves as a DNA repair enzyme, only two mammalian homologs have been confirmed to repair DNA in vivo. The other mammalian homologs have remarkably diverse substrate specificities and biological functions. Substrates recognized by the different AlkB homologs comprise erroneous methyl- and etheno adducts in DNA, unique wobble uridine modifications in certain tRNAs, methylated adenines in mRNA, and methylated lysines on proteins. The phenotypes of organisms lacking or overexpressing individual AlkB homologs include obesity, severe sensitivity to inflammation, infertility, growth retardation, and multiple malformations. Here we review the present knowledge of the mammalian AlkB homologs and their implications for human disease and development.
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Affiliation(s)
- Rune Ougland
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, The Norwegian Radium Hospital, 0310 Oslo, Norway
| | - Torbjørn Rognes
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Department of Informatics, University of Oslo, 0316 Oslo, Norway
| | - Arne Klungland
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Elisabeth Larsen
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
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Mielecki D, Grzesiuk E. Ada response - a strategy for repair of alkylated DNA in bacteria. FEMS Microbiol Lett 2014; 355:1-11. [PMID: 24810496 PMCID: PMC4437013 DOI: 10.1111/1574-6968.12462] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/04/2014] [Accepted: 05/05/2014] [Indexed: 11/29/2022] Open
Abstract
Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N3-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER); toxic N1-methyladenine (1meA) and N3-methylcytosine (3meC), induced in DNA and RNA, are removed by AlkB dioxygenase; and mutagenic and cytotoxic O6-methylguanine (O6meG) is repaired by Ada methyltransferase. In Escherichia coli, Ada response involves the expression of four genes, ada, alkA, alkB, and aidB, encoding respective proteins Ada, AlkA, AlkB, and AidB. The Ada response is conserved among many bacterial species; however, it can be organized differently, with diverse substrate specificity of the particular proteins. Here, an overview of the organization of the Ada regulon and function of individual proteins is presented. We put special effort into the characterization of AlkB dioxygenases, their substrate specificity, and function in the repair of alkylation lesions in DNA/RNA.
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Affiliation(s)
- Damian Mielecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
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