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Smerdon MJ, Wyrick JJ, Delaney S. A half century of exploring DNA excision repair in chromatin. J Biol Chem 2023; 299:105118. [PMID: 37527775 PMCID: PMC10498010 DOI: 10.1016/j.jbc.2023.105118] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 08/03/2023] Open
Abstract
DNA in eukaryotic cells is packaged into the compact and dynamic structure of chromatin. This packaging is a double-edged sword for DNA repair and genomic stability. Chromatin restricts the access of repair proteins to DNA lesions embedded in nucleosomes and higher order chromatin structures. However, chromatin also serves as a signaling platform in which post-translational modifications of histones and other chromatin-bound proteins promote lesion recognition and repair. Similarly, chromatin modulates the formation of DNA damage, promoting or suppressing lesion formation depending on the chromatin context. Therefore, the modulation of DNA damage and its repair in chromatin is crucial to our understanding of the fate of potentially mutagenic and carcinogenic lesions in DNA. Here, we survey many of the landmark findings on DNA damage and repair in chromatin over the last 50 years (i.e., since the beginning of this field), focusing on excision repair, the first repair mechanism studied in the chromatin landscape. For example, we highlight how the impact of chromatin on these processes explains the distinct patterns of somatic mutations observed in cancer genomes.
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Affiliation(s)
- Michael J Smerdon
- Biochemistry and Biophysics, School of Molecular Biosciences, Washington State University, Pullman, Washington, USA.
| | - John J Wyrick
- Genetics and Cell Biology, School of Molecular Biosciences, Washington State University, Pullman, Washington, USA
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
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Ryan BJ, Weaver TM, Spencer JJ, Freudenthal BD. Generation of Recombinant Nucleosomes Containing Site-Specific DNA Damage. Methods Mol Biol 2023; 2701:55-76. [PMID: 37574475 PMCID: PMC10794041 DOI: 10.1007/978-1-0716-3373-1_4] [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] [Indexed: 08/15/2023]
Abstract
Eukaryotic DNA exists in chromatin, where the genomic DNA is packaged into a fundamental repeating unit known as the nucleosome. In this chromatin environment, our genomic DNA is constantly under attack by exogenous and endogenous stressors that can lead to DNA damage. Importantly, this DNA damage must be repaired to prevent the accumulation of mutations and ensure normal cellular function. To date, most in-depth biochemical studies of DNA repair proteins have been performed in the context of free duplex DNA. However, chromatin can serve as a barrier that DNA repair enzymes must navigate in order find, access, and process DNA damage in the cell. To facilitate future studies of DNA repair in chromatin, we describe a protocol for generating nucleosome containing site-specific DNA damage that can be utilized for a variety of in vitro applications. This protocol describes several key steps including how to generate damaged DNA oligonucleotides, the expression and purification of recombinant histones, the refolding of histone complexes, and the reconstitution of nucleosomes containing site-specific DNA damage. These methods will enable researchers to generate nucleosomes containing site-specific DNA damage for extensive biochemical and structural studies of DNA repair in the nucleosome.
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Affiliation(s)
- Benjamin J Ryan
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Tyler M Weaver
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Jonah J Spencer
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS, USA.
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Maschari D, Saxena G, Law TD, Walsh E, Campbell MC, Consitt LA. Lactate-induced lactylation in skeletal muscle is associated with insulin resistance in humans. Front Physiol 2022; 13:951390. [PMID: 36111162 PMCID: PMC9468271 DOI: 10.3389/fphys.2022.951390] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022] Open
Abstract
Elevated circulating lactate has been associated with obesity and insulin resistance. The aim of the current study was to determine if lactate-induced lysine lactylation (kla), a post-translational modification, was present in human skeletal muscle and related to insulin resistance. Fifteen lean (Body Mass Index: 22.1 ± 0.5 kg/m2) and fourteen obese (40.6 ± 1.4 kg/m2) adults underwent a muscle biopsy and 2-h oral glucose tolerance test. Skeletal muscle lactylation was increased in obese compared to lean females (19%, p < 0.05) and associated with insulin resistance (r = 0.37, p < 0.05) in the whole group. Skeletal muscle lactylation levels were significantly associated with markers of anaerobic metabolism (plasma lactate and skeletal muscle lactate dehydrogenase [LDH], p < 0.05) and negatively associated with markers of oxidative metabolism (skeletal muscle cytochrome c oxidase subunit 4 and Complex I [pyruvate] OXPHOS capacity, p < 0.05). Treatment of primary human skeletal muscle cells (HSkMC) with sodium lactate for 24 h increased protein lactylation and IRS-1 serine 636 phosphorylation in a similar dose-dependent manner (p < 0.05). Inhibition of glycolysis (with 2-deoxy-d-glucose) or LDH-A (with sodium oxamate or LDH-A siRNA) for 24 h reduced HSkMC lactylation which paralleled reductions in culture media lactate accumulation. This study identified the existence of a lactate-derived post-translational modification in human skeletal muscle and suggests skeletal muscle lactylation could provide additional insight into the regulation of skeletal muscle metabolism, including insulin resistance.
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Affiliation(s)
- Dominic Maschari
- College of Health Sciences and Professions, Ohio University, Athens, OH, United States
| | - Gunjan Saxena
- Department of Biomedical Sciences, Ohio University, Athens, OH, United States
| | - Timothy D. Law
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, United States
| | - Erin Walsh
- Biological Sciences Department, Ohio University, Athens, OH, United States
| | - Mason C. Campbell
- Biological Sciences Department, Ohio University, Athens, OH, United States
| | - Leslie A Consitt
- Department of Biomedical Sciences, Ohio University, Athens, OH, United States
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH, United States
- Diabetes Institute, Ohio University, Athens, OH, United States
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Monitoring DNA polymerase β mitochondrial localization and dynamics. DNA Repair (Amst) 2022; 116:103357. [PMID: 35717762 PMCID: PMC9253048 DOI: 10.1016/j.dnarep.2022.103357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 11/22/2022]
Abstract
Mouse fibroblasts lacking (null) DNA polymerase β (pol β) were transfected with fluorescently tagged pol β and stained with biomarkers to allow visualization within living cells by confocal microscopy. Transient transfection resulted in varying pol β expression levels. Separating cells into three groups based on pol β fluorescence intensity and morphological distribution, permitted analysis of the concentration dependence and spatial distribution of cytoplasmic pol β. Colocalization between pol β and mitochondria was pol β concentration dependent. A decrease in overlap with nucleoids containing mitochondrial DNA (mtDNA) was observed at the highest pol β intensity where pol β exhibits a tubular appearance, suggesting the ability to load elevated levels of pol β into mitochondria readily available for relocation to damaged mtDNA. The dynamics of pol β and mitochondrial nucleoids were followed by confocal recording of time series images. Two populations of mitochondrial nucleoids were observed, with and without pol β. Micro-irradiation, known to form DNA single-strand breaks, in a line across nucleus and cytoplasm of pol β stably transfected cells enhanced apparent localization of pol β with mitochondria in the perinuclear region of the cytoplasm near the nuclear membrane. Exposure of pol β expressing cells to H2O2 resulted in a time-dependent increase in cytoplasmic pol β observed by immunofluorescence analysis of fixed cells. Further screening revealed increased levels of colocalization of pol β with a mitochondrial probe and an increase in oxidative DNA damage in the cytoplasm. ELISA quantification confirmed an increase of an oxidative mitochondrial base lesion, 7,8-dihydro-8-oxoguanine, after H2O2 treatment. Taken together, the results suggest that pol β is recruited to mitochondria in response to oxidatively-induced mtDNA damage to participate in mtDNA repair.
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dCas9 binding inhibits the initiation of base excision repair in vitro. DNA Repair (Amst) 2022; 109:103257. [PMID: 34847381 PMCID: PMC8748382 DOI: 10.1016/j.dnarep.2021.103257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/08/2021] [Accepted: 11/16/2021] [Indexed: 01/03/2023]
Abstract
Cas9 targets DNA during genome editing by forming an RNA:DNA heteroduplex (R-loop) between the Cas9-bound guide RNA and the targeted DNA strand. We have recently demonstrated that R-loop formation by catalytically inactive Cas9 (dCas9) is inherently mutagenic, in part, by promoting spontaneous cytosine deamination within the non-targeted single-stranded DNA of the dCas9-induced R-loop. However, the extent to which dCas9 binding and R-loop formation affect the subsequent repair of uracil lesions or other damaged DNA bases is unclear. Here, we show that DNA binding by dCas9 inhibits initiation of base excision repair (BER) for uracil lesions in vitro. Our data indicate that cleavage of uracil lesions by Uracil-DNA glycosylase (UDG) is generally inhibited at dCas9-bound DNA, in both the dCas9:sgRNA-bound target strand (TS) or the single-stranded non-target strand (NT). However, cleavage of a uracil lesion within the base editor window of the NT strand was less inhibited than at other locations, indicating that this site is more permissive to UDG activity. Furthermore, our data suggest that dCas9 binding to PAM sites can inhibit UDG activity. However, this non-specific inhibition can be relieved with the addition of an sgRNA lacking sequence complementarity to the DNA substrate. Moreover, we show that dCas9 binding also inhibits human single-strand selective monofunctional uracil-DNA glycosylase (SMUG1). Structural analysis of a Cas9-bound target site subsequently suggests a molecular mechanism for BER inhibition. Taken together, our results imply that dCas9 (or Cas9) binding may promote background mutagenesis by inhibiting the removal of DNA base lesions by BER.
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Fleming AM, Burrows CJ. Chemistry of ROS-mediated oxidation to the guanine base in DNA and its biological consequences. Int J Radiat Biol 2022; 98:452-460. [PMID: 34747670 PMCID: PMC8881305 DOI: 10.1080/09553002.2021.2003464] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE One outcome of DNA damage from hydroxyl radical generated by ionizing radiation (IR) or by the Fenton reaction is oxidation of the nucleobases, especially guanine (G). While 8-oxo-7,8-dihydroguanine (OG) is a commonly studied oxidized lesion, several others are formed in high abundance, including 5-carboxamido-5-formamido-2-iminohydantoin (2Ih), a prevalent product in in vitro chemistry that is challenging to study from cellular sources. In this short review, we have a goal of explaining new insights into hydroxyl radical-induced oxidation chemistry of G in DNA and comparing it to endogenous DNA damage, as well as commenting on the biological outcomes of DNA base damage. CONCLUSIONS Pathways of oxidation of G are discussed and a comparison is made between IR (hydroxyl radical chemistry) and endogenous oxidative stress that largely forms carbonate radical anion as a reactive intermediate. These pathways overlap with the formation of OG and 2Ih, but other guanine-derived lesions are more pathway specific. The biological consequences of guanine oxidation include both mutagenesis and epigenetics; a new mechanism of gene regulation via the base excision repair pathway is described for OG, whereas the impact of IR in forming guanine modifications may be to confound this process in addition to introduction of mutagenic sites.
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Thompson MK, Sobol RW, Prakash A. Exploiting DNA Endonucleases to Advance Mechanisms of DNA Repair. BIOLOGY 2021; 10:530. [PMID: 34198612 PMCID: PMC8232306 DOI: 10.3390/biology10060530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/17/2022]
Abstract
The earliest methods of genome editing, such as zinc-finger nucleases (ZFN) and transcription activator-like effector nucleases (TALENs), utilize customizable DNA-binding motifs to target the genome at specific loci. While these approaches provided sequence-specific gene-editing capacity, the laborious process of designing and synthesizing recombinant nucleases to recognize a specific target sequence, combined with limited target choices and poor editing efficiency, ultimately minimized the broad utility of these systems. The discovery of clustered regularly interspaced short palindromic repeat sequences (CRISPR) in Escherichia coli dates to 1987, yet it was another 20 years before CRISPR and the CRISPR-associated (Cas) proteins were identified as part of the microbial adaptive immune system, by targeting phage DNA, to fight bacteriophage reinfection. By 2013, CRISPR/Cas9 systems had been engineered to allow gene editing in mammalian cells. The ease of design, low cytotoxicity, and increased efficiency have made CRISPR/Cas9 and its related systems the designer nucleases of choice for many. In this review, we discuss the various CRISPR systems and their broad utility in genome manipulation. We will explore how CRISPR-controlled modifications have advanced our understanding of the mechanisms of genome stability, using the modulation of DNA repair genes as examples.
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Affiliation(s)
- Marlo K. Thompson
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Robert W. Sobol
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Pharmacology, University of South Alabama, Mobile, AL 36688, USA
| | - Aishwarya Prakash
- Mitchell Cancer Institute, University of South Alabama Health, Mobile, AL 36604, USA; (M.K.T.); (R.W.S.)
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
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Karakaidos P, Karagiannis D, Rampias T. Resolving DNA Damage: Epigenetic Regulation of DNA Repair. Molecules 2020; 25:molecules25112496. [PMID: 32471288 PMCID: PMC7321228 DOI: 10.3390/molecules25112496] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/18/2022] Open
Abstract
Epigenetic research has rapidly evolved into a dynamic field of genome biology. Chromatin regulation has been proved to be an essential aspect for all genomic processes, including DNA repair. Chromatin structure is modified by enzymes and factors that deposit, erase, and interact with epigenetic marks such as DNA and histone modifications, as well as by complexes that remodel nucleosomes. In this review we discuss recent advances on how the chromatin state is modulated during this multi-step process of damage recognition, signaling, and repair. Moreover, we examine how chromatin is regulated when different pathways of DNA repair are utilized. Furthermore, we review additional modes of regulation of DNA repair, such as through the role of global and localized chromatin states in maintaining expression of DNA repair genes, as well as through the activity of epigenetic enzymes on non-nucleosome substrates. Finally, we discuss current and future applications of the mechanistic interplays between chromatin regulation and DNA repair in the context cancer treatment.
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Affiliation(s)
| | - Dimitris Karagiannis
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA;
| | - Theodoros Rampias
- Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece;
- Correspondence: ; Tel.: +30-210-659-7469
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Beecher M, Kumar N, Jang S, Rapić-Otrin V, Van Houten B. Expanding molecular roles of UV-DDB: Shining light on genome stability and cancer. DNA Repair (Amst) 2020; 94:102860. [PMID: 32739133 DOI: 10.1016/j.dnarep.2020.102860] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 01/13/2023]
Abstract
UV-damaged DNA binding protein (UV-DDB) is a heterodimeric complex, composed of DDB1 and DDB2, and is involved in global genome nucleotide excision repair. Mutations in DDB2 are associated with xeroderma pigmentosum complementation group E. UV-DDB forms a ubiquitin E3 ligase complex with cullin-4A and RBX that helps to relax chromatin around UV-induced photoproducts through the ubiquitination of histone H2A. After providing a brief historical perspective on UV-DDB, we review our current knowledge of the structure and function of this intriguing repair protein. Finally, this article discusses emerging data suggesting that UV-DDB may have other non-canonical roles in base excision repair and the etiology of cancer.
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Affiliation(s)
- Maria Beecher
- Molecular Pharmacology Graduate Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Namrata Kumar
- Molecular Genetics and Developmental Biology Graduate Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sunbok Jang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Vesna Rapić-Otrin
- Department of Microbiology and Molecular Genetics, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Bennett Van Houten
- Molecular Pharmacology Graduate Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; Molecular Genetics and Developmental Biology Graduate Program, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA; UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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