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Feng B, Zheng J, Cai Y, Han Y, Han Y, Wu J, Feng J, Zheng K. An Epigenetic Manifestation of Alzheimer's Disease: DNA Methylation. ACTAS ESPANOLAS DE PSIQUIATRIA 2024; 52:365-374. [PMID: 38863055 PMCID: PMC11190457 DOI: 10.62641/aep.v52i3.1595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Alzheimer's disease (AD), the most common form of dementia, has a complex pathogenesis. The number of AD patients has increased in recent years due to population aging, while a trend toward a younger age of onset has arisen, imposing a substantial burden on society and families, and garnering extensive attention. DNA methylation has recently been revealed to play an important role in AD onset and progression. DNA methylation is a critical mechanism regulating gene expression, and alterations in this mechanism dysregulate gene expression and disrupt important pathways, including oxidative stress responses, inflammatory reactions, and protein degradation processes, eventually resulting in disease. Studies have revealed widespread changes in AD patients' DNA methylation in the peripheral blood and brain tissues, affecting multiple signaling pathways and severely impacting neuronal cell and synaptic functions. This review summarizes the role of DNA methylation in the pathogenesis of AD, aiming to provide a theoretical basis for its early prevention and treatment.
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Affiliation(s)
- Boyi Feng
- Department of Chronic Disease, Longhua District Center for Chronic Disease Control/Mental Health, 510080 Shenzhen, Guangdong, China
- Shenzhen Guangming District People's Hospital, 518107 Shenzhen, Guangdong, China
| | - Junli Zheng
- Department of Chronic Disease, Longhua District Center for Chronic Disease Control/Mental Health, 510080 Shenzhen, Guangdong, China
| | - Ying Cai
- Public Health Service Center, Bao'an District, 518100 Shenzhen, Guangdong, China
| | - Yaguang Han
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, 150000 Harbin, Heilongjiang, China
| | - Yanhua Han
- First Affiliated Hospital, Heilongjiang University of Chinese Medicine, 150000 Harbin, Heilongjiang, China
| | - Jiaqi Wu
- Department of Chronic Disease, Longhua District Center for Chronic Disease Control/Mental Health, 510080 Shenzhen, Guangdong, China
| | - Jun Feng
- Department of Chronic Disease, Longhua District Center for Chronic Disease Control/Mental Health, 510080 Shenzhen, Guangdong, China
| | - Kai Zheng
- Department of Chronic Disease, Longhua District Center for Chronic Disease Control/Mental Health, 510080 Shenzhen, Guangdong, China
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Kriukienė E, Tomkuvienė M, Klimašauskas S. 5-Hydroxymethylcytosine: the many faces of the sixth base of mammalian DNA. Chem Soc Rev 2024; 53:2264-2283. [PMID: 38205583 DOI: 10.1039/d3cs00858d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Epigenetic phenomena play a central role in cell regulatory processes and are important factors for understanding complex human disease. One of the best understood epigenetic mechanisms is DNA methylation. In the mammalian genome, cytosines (C) in CpG dinucleotides were long known to undergo methylation at the 5-position of the pyrimidine ring (mC). Later it was found that mC can be oxidized to 5-hydroxymethylcytosine (hmC) or even further to 5-formylcytosine (fC) and to 5-carboxylcytosine (caC) by the action of 2-oxoglutarate-dependent dioxygenases of the TET family. These findings unveiled a long elusive mechanism of active DNA demethylation and bolstered a wave of studies in the area of epigenetic regulation in mammals. This review is dedicated to critical assessment of recent data on biochemical and chemical aspects of the formation and conversion of hmC in DNA, analytical techniques used for detection and mapping of this nucleobase in mammalian genomes as well as epigenetic roles of hmC in DNA replication, transcription, cell differentiation and human disease.
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Affiliation(s)
- Edita Kriukienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257 Vilnius, Lithuania.
| | - Miglė Tomkuvienė
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257 Vilnius, Lithuania.
| | - Saulius Klimašauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Saulėtekio al. 7, LT-10257 Vilnius, Lithuania.
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Hardtke HA, Zhang YJ. Collaborators or competitors: the communication between RNA polymerase II and the nucleosome during eukaryotic transcription. Crit Rev Biochem Mol Biol 2024; 59:1-19. [PMID: 38288999 PMCID: PMC11209794 DOI: 10.1080/10409238.2024.2306365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 01/12/2024] [Indexed: 04/22/2024]
Abstract
Decades of scientific research have been devoted to unraveling the intricacies of eukaryotic transcription since the groundbreaking discovery of eukaryotic RNA polymerases in the late 1960s. RNA polymerase II, the polymerase responsible for mRNA synthesis, has always attracted the most attention. Despite its structural resemblance to its bacterial counterpart, eukaryotic RNA polymerase II faces a unique challenge in progressing transcription due to the presence of nucleosomes that package DNA in the nuclei. In this review, we delve into the impact of RNA polymerase II and histone signaling on the progression of eukaryotic transcription. We explore the pivotal points of interactions that bridge the RNA polymerase II and histone signaling systems. Finally, we present an analysis of recent cryo-electron microscopy structures, which captured RNA polymerase II-nucleosome complexes at different stages of the transcription cycle. The combination of the signaling crosstalk and the direct visualization of RNA polymerase II-nucleosome complexes provides a deeper understanding of the communication between these two major players in eukaryotic transcription.
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Affiliation(s)
- Haley A. Hardtke
- Department of Molecular Biosciences, University of Texas, Austin
| | - Y. Jessie Zhang
- Department of Molecular Biosciences, University of Texas, Austin
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Breindl M, Spitzer D, Gerasimaitė R, Kairys V, Schubert T, Henfling R, Schwartz U, Lukinavičius G, Manelytė L. Biochemical and cellular insights into the Baz2B protein, a non-catalytic subunit of the chromatin remodeling complex. Nucleic Acids Res 2024; 52:337-354. [PMID: 38000389 PMCID: PMC10783490 DOI: 10.1093/nar/gkad1096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 09/21/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Baz2B is a regulatory subunit of the ATP-dependent chromatin remodeling complexes BRF1 and BRF5, which control access to DNA during DNA-templated processes. Baz2B has been implicated in several diseases and also in unhealthy ageing, however limited information is available on the domains and cellular roles of Baz2B. To gain more insight into the Baz2B function, we biochemically characterized the TAM (Tip5/ARBP/MBD) domain with the auxiliary AT-hook motifs and the bromodomain (BRD). We observed alterations in histone code recognition in bromodomains carrying cancer-associated point mutations, suggesting their potential involvement in disease. Furthermore, the depletion of Baz2B in the Hap1 cell line resulted in altered cell morphology, reduced colony formation and perturbed transcriptional profiles. Despite that, super-resolution microscopy images revealed no changes in the overall chromatin structure in the absence of Baz2B. These findings provide insights into the biological function of Baz2B.
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Affiliation(s)
- Matthias Breindl
- Biochemistry III, University of Regensburg, Regensburg DE-93053, Germany
| | - Dominika Spitzer
- Biochemistry III, University of Regensburg, Regensburg DE-93053, Germany
| | - Rūta Gerasimaitė
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, DE-37077 Göttingen, Germany
| | - Visvaldas Kairys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius LT-10257, Lithuania
| | | | - Ramona Henfling
- Biochemistry III, University of Regensburg, Regensburg DE-93053, Germany
| | - Uwe Schwartz
- NGS Analysis Center, University of Regensburg, Regensburg DE-93053, Germany
| | - Gražvydas Lukinavičius
- Chromatin Labeling and Imaging Group, Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, DE-37077 Göttingen, Germany
| | - Laura Manelytė
- Biochemistry III, University of Regensburg, Regensburg DE-93053, Germany
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Vilkaitis G, Masevičius V, Kriukienė E, Klimašauskas S. Chemical Expansion of the Methyltransferase Reaction: Tools for DNA Labeling and Epigenome Analysis. Acc Chem Res 2023; 56:3188-3197. [PMID: 37904501 PMCID: PMC10666283 DOI: 10.1021/acs.accounts.3c00471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/01/2023]
Abstract
DNA is the genetic matter of life composed of four major nucleotides which can be further furnished with biologically important covalent modifications. Among the variety of enzymes involved in DNA metabolism, AdoMet-dependent methyltransferases (MTases) combine the recognition of specific sequences and covalent methylation of a target nucleotide. The naturally transferred methyl groups play important roles in biological signaling, but they are poor physical reporters and largely resistant to chemical derivatization. Therefore, an obvious strategy to unlock the practical utility of the methyltransferase reactions is to enable the transfer of "prederivatized" (extended) versions of the methyl group.However, previous enzymatic studies of extended AdoMet analogs indicated that the transalkylation reactions are drastically impaired as the size of the carbon chain increases. In collaborative efforts, we proposed that, akin to enhanced SN2 reactivity of allylic and propargylic systems, addition of a π orbital next to the transferable carbon atom might confer the needed activation of the reaction. Indeed, we found that MTase-catalyzed transalkylations of DNA with cofactors containing a double or a triple C-C bond in the β position occurred in a robust and sequence-specific manner. Altogether, this breakthrough approach named mTAG (methyltransferase-directed transfer of activated groups) has proven instrumental for targeted labeling of DNA and other types of biomolecules (using appropriate MTases) including RNA and proteins.Our further work focused on the propargylic cofactors and their reactions with DNA cytosine-5 MTases, a class of MTases common for both prokaryotes and eukaryotes. Here, we learned that the 4-X-but-2-yn-1-yl (X = polar group) cofactors suffered from a rapid loss of activity in aqueous buffers due to susceptibility of the triple bond to hydration. This problem was remedied by synthetically increasing the separation between X and the triple bond from one to three carbon units (6-X-hex-2-ynyl cofactors). To further optimize the transfer of the bulkier groups, we performed structure-guided engineering of the MTase cofactor pocket. Alanine replacements of two conserved residues conferred substantial improvements of the transalkylation activity with M.HhaI and three other engineered bacterial C5-MTases. Of particular interest were CpG-specific DNA MTases (M.SssI), which proved valuable tools for studies of mammalian methylomes and chemical probing of DNA function.Inspired by the successful repurposing of bacterial enzymes, we turned to more complex mammalian C5-MTases (Dnmt1, Dnmt3A, and Dnmt3B) and asked if they could ultimately lead to mTAG labeling inside mammalian cells. Our efforts to engineer mouse Dnmt1 produced a variant (Dnmt1*) that enabled efficient Dnmt1-directed deposition of 6-azide-hexynyl groups on DNA in vitro. CRISPR-Cas9 editing of the corresponding codons in the genomic Dnmt1 alleles established endogenous expression of Dnmt1* in mouse embryonic stem cells. To circumvent the poor cellular uptake of AdoMet and its analogs, we elaborated their efficient internalization by electroporation, which has finally enabled selective catalysis-dependent azide tagging of natural Dnmt1 targets in live mammalian cells. The deposited chemical groups were then exploited as "click" handles for reading adjoining sequences and precise genomic mapping of the methylation sites. These findings offer unprecedented inroads into studies of DNA methylation in a wide range of eukaryotic model systems.
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Affiliation(s)
- Giedrius Vilkaitis
- Institute
of Biotechnology, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania
| | - Viktoras Masevičius
- Institute
of Biotechnology, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania
- Institute
of Chemistry, Department of Chemistry and Geosciences, Vilnius University, LT-03225 Vilnius, Lithuania
| | - Edita Kriukienė
- Institute
of Biotechnology, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania
| | - Saulius Klimašauskas
- Institute
of Biotechnology, Life Sciences Center, Vilnius University, LT-10257 Vilnius, Lithuania
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DNA Labeling Using DNA Methyltransferases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:535-562. [DOI: 10.1007/978-3-031-11454-0_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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