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Oswalt LE, Eichman BF. NEIL3: A unique DNA glycosylase involved in interstrand DNA crosslink repair. DNA Repair (Amst) 2024; 139:103680. [PMID: 38663144 PMCID: PMC11162926 DOI: 10.1016/j.dnarep.2024.103680] [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: 01/16/2024] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 05/09/2024]
Abstract
Endonuclease VIII-like 3 (NEIL3) is a versatile DNA glycosylase that repairs a diverse array of chemical modifications to DNA. Unlike other glycosylases, NEIL3 has a preference for lesions within single-strand DNA and at single/double-strand DNA junctions. Beyond its canonical role in base excision repair of oxidized DNA, NEIL3 initiates replication-dependent interstrand DNA crosslink repair as an alternative to the Fanconi Anemia pathway. This review outlines our current understanding of NEIL3's biological functions, role in disease, and three-dimensional structure as it pertains to substrate specificity and catalytic mechanism.
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Affiliation(s)
- Leah E Oswalt
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA.
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2
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Price NE, Gates KS. Novel Processes Associated with the Repair of Interstrand Cross-Links Derived from Abasic Sites in Duplex DNA: Roles for the Base Excision Repair Glycosylase NEIL3 and the SRAP Protein HMCES. Chem Res Toxicol 2024; 37:199-207. [PMID: 38198604 DOI: 10.1021/acs.chemrestox.3c00345] [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
Recent studies have defined a novel pathway for the repair of interstrand cross-links derived from the reaction of an adenine residue with an apurinic/apyrimidinic (AP) site on the opposing strand of DNA (dA-AP ICL). Stalling of a replication fork at the dA-AP ICL triggers TRAIP-dependent ubiquitylation of the CMG helicase that recruits the base excision repair glycosylase NEIL3 to the lesion. NEIL3 unhooks the dA-AP ICL to regenerate the native adenine residue on one strand and an AP site on the other strand. Covalent capture of the abasic site by the SRAP protein HMCES protects against genomic instability that would result from cleavage of the abasic site in the context of single-stranded DNA at the replication fork. After repair synthesis moves the HMCES-AP adduct into the context of double-stranded DNA, the DNA-protein cross-link is resolved by a nonproteolytic mechanism involving dissociation of thiazolidine attachment. The AP site in duplex DNA is then repaired by the base excision repair pathway.
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Affiliation(s)
- Nathan E Price
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
- Department of Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
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3
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Gomina A, Islam T, Shim G, Lei Z, Gates KS. Formation and Properties of DNA Adducts Generated by Reactions of Abasic Sites with 1,2-Aminothiols Including Cysteamine, Cysteine Methyl Ester, and Peptides Containing N-Terminal Cysteine Residues. Chem Res Toxicol 2024; 37:395-406. [PMID: 38181204 DOI: 10.1021/acs.chemrestox.3c00344] [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] [Indexed: 01/07/2024]
Abstract
The reaction of 1,2-aminothiol groups with aldehyde residues in aqueous solution generates thiazolidine products, and this process has been developed as a catalyst-free click reaction for bioconjugation. The work reported here characterized reactions of the biologically relevant 1,2-aminothiols including cysteamine, cysteine methyl ester, and peptides containing N-terminal cysteine residues with the aldehyde residue of apurinic/apyrimidinic (AP) sites in DNA oligomers. These 1,2-aminothiol-containing compounds rapidly generated adducts with AP sites in single-stranded and double-stranded DNA. NMR and MALDI-TOF-MS analyses provided evidence that the reaction generated a thiazolidine product. Conversion of an AP site to a thiazolidine-AP adduct protected against the rapid cleavage normally induced at AP sites by the endonuclease action of the enzyme APE1 and the AP-lyase activity of the biogenic amine spermine. In the presence of excess 1,2-aminothiols, the thiazolidine-AP adducts underwent slow strand cleavage via a β-lyase reaction that generated products with 1,2-aminothiol-modified sugar residues on the 3'-end of the strand break. In the absence of excess 1,2-aminothiols, the thiazolidine-AP adducts dissociated to release the parent AP-containing oligonucleotide. The properties of the thiazolidine-AP adducts described here mirror critical properties of SRAP proteins HMCES and YedK that capture AP sites in single-stranded regions of cellular DNA and protect them from cleavage.
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Affiliation(s)
- Anuoluwapo Gomina
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Tanhaul Islam
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Garam Shim
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
| | - Zhentian Lei
- MU Metabolomics Center, University of Missouri, 240F Christopher S. Bond Life Science Center, Columbia, Missouri 65211, United States
| | - Kent S Gates
- Department of Chemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
- Department of Biochemistry, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, United States
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4
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Rua-Fernandez J, Lovejoy CA, Mehta KPM, Paulin KA, Toudji YT, Giansanti C, Eichman BF, Cortez D. Self-reversal facilitates the resolution of HMCES DNA-protein crosslinks in cells. Cell Rep 2023; 42:113427. [PMID: 37950866 PMCID: PMC10842721 DOI: 10.1016/j.celrep.2023.113427] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/02/2023] [Accepted: 10/27/2023] [Indexed: 11/13/2023] Open
Abstract
Abasic sites are common DNA lesions stalling polymerases and threatening genome stability. When located in single-stranded DNA (ssDNA), they are shielded from aberrant processing by 5-hydroxymethyl cytosine, embryonic stem cell (ESC)-specific (HMCES) via a DNA-protein crosslink (DPC) that prevents double-strand breaks. Nevertheless, HMCES-DPCs must be removed to complete DNA repair. Here, we find that DNA polymerase α inhibition generates ssDNA abasic sites and HMCES-DPCs. These DPCs are resolved with a half-life of approximately 1.5 h. HMCES can catalyze its own DPC self-reversal reaction, which is dependent on glutamate 127 and is favored when the ssDNA is converted to duplex DNA. When the self-reversal mechanism is inactivated in cells, HMCES-DPC removal is delayed, cell proliferation is slowed, and cells become hypersensitive to DNA damage agents that increase AP (apurinic/apyrimidinic) site formation. In these circumstances, proteolysis may become an important mechanism of HMCES-DPC resolution. Thus, HMCES-DPC formation followed by self-reversal is an important mechanism for ssDNA AP site management.
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Affiliation(s)
- Jorge Rua-Fernandez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Courtney A Lovejoy
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kavi P M Mehta
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Katherine A Paulin
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Yasmine T Toudji
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Celeste Giansanti
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Brandt F Eichman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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5
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Donsbach M, Dürauer S, Grünert F, Nguyen KT, Nigam R, Yaneva D, Weickert P, Bezalel‐Buch R, Semlow DR, Stingele J. A non-proteolytic release mechanism for HMCES-DNA-protein crosslinks. EMBO J 2023; 42:e113360. [PMID: 37519246 PMCID: PMC10505908 DOI: 10.15252/embj.2022113360] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 08/01/2023] Open
Abstract
The conserved protein HMCES crosslinks to abasic (AP) sites in ssDNA to prevent strand scission and the formation of toxic dsDNA breaks during replication. Here, we report a non-proteolytic release mechanism for HMCES-DNA-protein crosslinks (DPCs), which is regulated by DNA context. In ssDNA and at ssDNA-dsDNA junctions, HMCES-DPCs are stable, which efficiently protects AP sites against spontaneous incisions or cleavage by APE1 endonuclease. In contrast, HMCES-DPCs are released in dsDNA, allowing APE1 to initiate downstream repair. Mechanistically, we show that release is governed by two components. First, a conserved glutamate residue, within HMCES' active site, catalyses reversal of the crosslink. Second, affinity to the underlying DNA structure determines whether HMCES re-crosslinks or dissociates. Our study reveals that the protective role of HMCES-DPCs involves their controlled release upon bypass by replication forks, which restricts DPC formation to a necessary minimum.
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Affiliation(s)
- Maximilian Donsbach
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
| | - Sophie Dürauer
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
| | - Florian Grünert
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
| | - Kha T Nguyen
- Division of Chemistry and Chemical EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Richa Nigam
- Division of Chemistry and Chemical EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Denitsa Yaneva
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
| | - Pedro Weickert
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
| | - Rachel Bezalel‐Buch
- Department of Biological Chemistry and Molecular BiophysicsWashington University School of MedicalSaint LouisMOUSA
| | - Daniel R Semlow
- Division of Chemistry and Chemical EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Julian Stingele
- Department of BiochemistryLudwig‐Maximilians‐University MunichMunichGermany
- Gene Center, Ludwig‐Maximilians‐University MunichMunichGermany
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6
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Eichman BF. Repair and tolerance of DNA damage at the replication fork: A structural perspective. Curr Opin Struct Biol 2023; 81:102618. [PMID: 37269798 PMCID: PMC10525001 DOI: 10.1016/j.sbi.2023.102618] [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: 03/07/2023] [Revised: 05/05/2023] [Accepted: 05/07/2023] [Indexed: 06/05/2023]
Abstract
The replication machinery frequently encounters DNA damage and other structural impediments that inhibit progression of the replication fork. Replication-coupled processes that remove or bypass the barrier and restart stalled forks are essential for completion of replication and for maintenance of genome stability. Errors in replication-repair pathways lead to mutations and aberrant genetic rearrangements and are associated with human diseases. This review highlights recent structures of enzymes involved in three replication-repair pathways: translesion synthesis, template switching and fork reversal, and interstrand crosslink repair.
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Affiliation(s)
- Brandt F Eichman
- Vanderbilt University, Department of Biological Sciences and Department of Biochemistry, 5270A MRBIII, 465 21st Ave S, Nashville, TN 37232 USA.
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7
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Liu C, Le BH, Xu W, Yang CH, Chen YH, Zhao L. Dual chemical labeling enables nucleotide-resolution mapping of DNA abasic sites and common alkylation damage in human mitochondrial DNA. Nucleic Acids Res 2023; 51:e73. [PMID: 37293974 PMCID: PMC10359467 DOI: 10.1093/nar/gkad502] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/01/2023] [Accepted: 05/26/2023] [Indexed: 06/10/2023] Open
Abstract
Mitochondrial DNA (mtDNA) modifications play an emerging role in innate immunity and inflammatory diseases. Nonetheless, relatively little is known regarding the locations of mtDNA modifications. Such information is critically important for deciphering their roles in mtDNA instability, mtDNA-mediated immune and inflammatory responses, and mitochondrial disorders. The affinity probe-based enrichment of lesion-containing DNA represents a key strategy for sequencing DNA modifications. Existing methods are limited in the enrichment specificity of abasic (AP) sites, a prevalent DNA modification and repair intermediate. Herein, we devise a novel approach, termed dual chemical labeling-assisted sequencing (DCL-seq), for mapping AP sites. DCL-seq features two designer compounds for enriching and mapping AP sites specifically at single-nucleotide resolution. For proof of principle, we mapped AP sites in mtDNA from HeLa cells under different biological conditions. The resulting AP site maps coincide with mtDNA regions with low TFAM (mitochondrial transcription factor A) coverage and with potential G-quadruplex-forming sequences. In addition, we demonstrated the broader applicability of the method in sequencing other DNA modifications in mtDNA, such as N7-methyl-2'-deoxyguanosine and N3-methyl-2'-deoxyadenosine, when coupled with a lesion-specific repair enzyme. Together, DCL-seq holds the promise to sequence multiple DNA modifications in various biological samples.
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Affiliation(s)
- Chaoxing Liu
- Department of Chemistry, University of California, Riverside, Riverside, CA 92521, USA
| | - Brandon H Le
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Wenyan Xu
- Department of Chemistry, University of California, Riverside, Riverside, CA 92521, USA
| | - Ching-Hsin Yang
- Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
| | - Yu Hsuan Chen
- Department of Chemistry, University of California, Riverside, Riverside, CA 92521, USA
| | - Linlin Zhao
- Department of Chemistry, University of California, Riverside, Riverside, CA 92521, USA
- Environmental Toxicology Graduate Program, University of California, Riverside, Riverside, CA 92521, USA
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8
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Rua-Fernandez J, Lovejoy CA, Mehta KPM, Paulin KA, Toudji YT, Eichman BF, Cortez D. Self-reversal facilitates the resolution of HMCES-DNA protein crosslinks in cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.14.544844. [PMID: 37398432 PMCID: PMC10312715 DOI: 10.1101/2023.06.14.544844] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Abasic sites are common DNA lesions that stall polymerases and threaten genome stability. When located in single-stranded DNA (ssDNA), they are shielded from aberrant processing by HMCES via a DNA-protein crosslink (DPC) that prevents double-strand breaks. Nevertheless, the HMCES-DPC must be removed to complete DNA repair. Here, we found that DNA polymerase α inhibition generates ssDNA abasic sites and HMCES-DPCs. These DPCs are resolved with a half-life of approximately 1.5 hours. Resolution does not require the proteasome or SPRTN protease. Instead, HMCES-DPC self-reversal is important for resolution. Biochemically, self-reversal is favored when the ssDNA is converted to duplex DNA. When the self-reversal mechanism is inactivated, HMCES-DPC removal is delayed, cell proliferation is slowed, and cells become hypersensitive to DNA damage agents that increase AP site formation. Thus, HMCES-DPC formation followed by self-reversal is an important mechanism for ssDNA AP site management.
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9
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Sugimoto Y, Masuda Y, Iwai S, Miyake Y, Kanao R, Masutani C. Novel mechanisms for the removal of strong replication-blocking HMCES- and thiazolidine-DNA adducts in humans. Nucleic Acids Res 2023; 51:4959-4981. [PMID: 37021581 PMCID: PMC10250235 DOI: 10.1093/nar/gkad246] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 03/16/2023] [Accepted: 03/27/2023] [Indexed: 04/07/2023] Open
Abstract
Apurinic/apyrimidinic (AP) sites are DNA lesions created under normal growth conditions that result in cytotoxicity, replication-blocks, and mutations. AP sites are susceptible to β-elimination and are liable to be converted to DNA strand breaks. HMCES (5-hydroxymethylcytosine binding, ES cell specific) protein interacts with AP sites in single stranded (ss) DNA exposed at DNA replication forks to generate a stable thiazolidine protein-DNA crosslink and protect cells against AP site toxicity. The crosslinked HMCES is resolved by proteasome-mediated degradation; however, it is unclear how HMCES-crosslinked ssDNA and the resulting proteasome-degraded HMCES adducts are processed and repaired. Here, we describe methods for the preparation of thiazolidine adduct-containing oligonucleotides and determination of their structure. We demonstrate that the HMCES-crosslink is a strong replication blocking adduct and that protease-digested HMCES adducts block DNA replication to a similar extent as AP sites. Moreover, we show that the human AP endonuclease APE1 incises DNA 5' to the protease-digested HMCES adduct. Interestingly, while HMCES-ssDNA crosslinks are stable, the crosslink is reversed upon the formation of dsDNA, possibly due to a catalytic reverse reaction. Our results shed new light on damage tolerance and repair pathways for HMCES-DNA crosslinks in human cells.
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Affiliation(s)
- Yohei Sugimoto
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Molecular Pharmaco-Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yuji Masuda
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Molecular Pharmaco-Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shigenori Iwai
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Yumi Miyake
- Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Rie Kanao
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Molecular Pharmaco-Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Chikahide Masutani
- Department of Genome Dynamics, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Department of Molecular Pharmaco-Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Abstract
Bacteria are continuously exposed to numerous endogenous and exogenous DNA-damaging agents. To maintain genome integrity and ensure cell survival, bacteria have evolved several DNA repair pathways to correct different types of DNA damage and non-canonical bases, including strand breaks, nucleotide modifications, cross-links, mismatches and ribonucleotide incorporations. Recent advances in genome-wide screens, the availability of thousands of whole-genome sequences and advances in structural biology have enabled the rapid discovery and characterization of novel bacterial DNA repair pathways and new enzymatic activities. In this Review, we discuss recent advances in our understanding of base excision repair and nucleotide excision repair, and we discuss several new repair processes including the EndoMS mismatch correction pathway and the MrfAB excision repair system.
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Affiliation(s)
- Katherine J Wozniak
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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Paulin KA, Cortez D, Eichman BF. The SOS response-associated peptidase (SRAP) domain of YedK catalyzes ring opening of abasic sites and reversal of its DNA-protein crosslink. J Biol Chem 2022; 298:102307. [PMID: 35934051 PMCID: PMC9436759 DOI: 10.1016/j.jbc.2022.102307] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/12/2022] Open
Abstract
Apurinic/apyrimidinic (AP, or abasic) sites in DNA are one of the most common forms of DNA damage. AP sites are reactive and form cross-links to both proteins and DNA, are prone to strand breakage, and inhibit DNA replication and transcription. The replication-associated AP site repair protein HMCES protects cells from strand breaks, inhibits mutagenic translesion synthesis, and participates in repair of interstrand DNA cross-links derived from AP sites by forming a stable thiazolidine DNA–protein cross-link (DPC) to AP sites in single-stranded DNA (ssDNA). Despite the importance of HMCES to genome maintenance and the evolutionary conservation of its catalytic SRAP (SOS Response Associated Peptidase) domain, the enzymatic mechanisms of DPC formation and resolution are unknown. Using the bacterial homolog YedK, we show that the SRAP domain catalyzes conversion of the AP site to its reactive, ring-opened aldehyde form, and we provide structural evidence for the Schiff base intermediate that forms prior to the more stable thiazolidine. We also report two new activities, whereby SRAP reacts with polyunsaturated aldehydes at DNA 3′-ends generated by bifunctional DNA glycosylases and catalyzes direct reversal of the DPC to regenerate the AP site, the latter of which we observe in both YedK and HMCES-SRAP proteins. Taken together, this work provides insights into possible mechanisms by which HMCES DPCs are resolved in cells.
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12
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Thompson PS, Cortez D. New insights into abasic site repair and tolerance. DNA Repair (Amst) 2020; 90:102866. [PMID: 32417669 PMCID: PMC7299775 DOI: 10.1016/j.dnarep.2020.102866] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022]
Abstract
Thousands of apurinic/apyrimidinic (AP or abasic) sites form in each cell, each day. This simple DNA lesion can have profound consequences to cellular function, genome stability, and disease. As potent blocks to polymerases, they interfere with the reading and copying of the genome. Since they provide no coding information, they are potent sources of mutation. Due to their reactive chemistry, they are intermediates in the formation of lesions that are more challenging to repair including double-strand breaks, interstrand crosslinks, and DNA protein crosslinks. Given their prevalence and deleterious consequences, cells have multiple mechanisms of repairing and tolerating these lesions. While base excision repair of abasic sites in double-strand DNA has been studied for decades, new interest in abasic site processing has come from more recent insights into how they are processed in single-strand DNA. In this review, we discuss the source of abasic sites, their biological consequences, tolerance mechanisms, and how they are repaired in double and single-stranded DNA.
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Affiliation(s)
- Petria S Thompson
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN, 37232, USA
| | - David Cortez
- Vanderbilt University School of Medicine, Department of Biochemistry, Nashville, TN, 37232, USA.
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