1
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Chakraborty A, Sreenivasmurthy SG, Miller W, Huai W, Biswas T, Mandal SM, Boscá L, Krishnan B, Ghosh G, Hazra T. Fructose-2,6-bisphosphate restores DNA repair activity of PNKP and ameliorates neurodegenerative symptoms in Huntington's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.26.564220. [PMID: 37961108 PMCID: PMC10634858 DOI: 10.1101/2023.10.26.564220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) are the two most prevalent polyglutamine (polyQ) neurodegenerative diseases, caused by CAG (encoding glutamine) repeat expansion in the coding region of the huntingtin (HTT) and ataxin-3 (ATXN3) proteins, respectively. We have earlier reported that the activity, but not the protein level, of an essential DNA repair enzyme, polynucleotide kinase 3'-phosphatase (PNKP), is severely abrogated in both HD and SCA3 resulting in accumulation of double-strand breaks in patients' brain genome. While investigating the mechanistic basis for the loss of PNKP activity and accumulation of DNA double-strand breaks leading to neuronal death, we observed that PNKP interacts with the nuclear isoform of 6-phosphofructo-2-kinase fructose-2,6-bisphosphatase 3 (PFKFB3). Depletion of PFKFB3 markedly abrogates PNKP activity without changing its protein level. Notably, the levels of both PFKFB3 and its product fructose-2,6 bisphosphate (F2,6BP), an allosteric modulator of glycolysis, are significantly lower in the nuclear extracts of post-mortem brain tissues of HD and SCA3 patients. Supplementation of F2,6BP restored PNKP activity in the nuclear extracts of patients' brain. Moreover, intracellular delivery of F2,6BP restored both the activity of PNKP and the integrity of transcribed genome in neuronal cells derived from striatum of HD mouse. Importantly, supplementing F2,6BP rescued the HD phenotype in Drosophila, suggesting F2,6BP to serve in vivo as a cofactor for the proper functionality of PNKP and thereby, of brain health. Our results thus provide a compelling rationale for exploring the therapeutic use of F2,6BP and structurally related compounds for treating polyQ diseases.
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Affiliation(s)
- Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | | | - Wyatt Miller
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Weihan Huai
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Tapan Biswas
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Santi Mohan Mandal
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Lisardo Boscá
- Instituto de Investigaciones Biomédicas Sols-Morreale (CSIC-UAM), and Centro de Investigación en Red en Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Balaji Krishnan
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Tapas Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
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2
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Piao X, Tang Y, Li X, Zhang W, Yang W, Xu X, Wang W, Jiang J, Xu J, Hu K, Xu M, Liu M, Sun M, Jin L. Supercoiled DNA percentage: A key in-process control of linear DNA template for mRNA drug substance manufacturing. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102223. [PMID: 38948330 PMCID: PMC11214521 DOI: 10.1016/j.omtn.2024.102223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 05/16/2024] [Indexed: 07/02/2024]
Abstract
The development of messenger RNA (mRNA) vaccines and therapeutics necessitates the production of high-quality in vitro-transcribed mRNA drug substance with specific critical quality attributes (CQAs), which are closely tied to the uniformity of linear DNA template. The supercoiled plasmid DNA is the precursor to the linear DNA template, and the supercoiled DNA percentage is commonly regarded as a key in-process control (IPC) during the manufacturing of linear DNA template. In this study, we investigate the influence of supercoiled DNA percentage on key mRNA CQAs, including purity, capping efficiency, double-stranded RNA (dsRNA), and distribution of poly(A) tail. Our findings reveal a significant impact of supercoiled DNA percentage on mRNA purity and in vitro transcription yield. Notably, we observe that the impact on mRNA purity can be mitigated through oligo-dT chromatography, alleviating the tight range of DNA supercoiled percentage to some extent. Overall, this study provides valuable insights into IPC strategies for DNA template chemistry, manufacturing, and controls (CMC) and process development for mRNA drug substance.
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Affiliation(s)
- Xijun Piao
- CATUG Biotechnology, Suzhou 215000, China
- Wuhan CATUG Biotechnology, Wuhan 430074, China
| | - Yujie Tang
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Xiuzhi Li
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Weicheng Zhang
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Wei Yang
- Wuhan CATUG Biotechnology, Wuhan 430074, China
| | - Xining Xu
- CATUG Biotechnology, Suzhou 215000, China
| | - Wenjing Wang
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Jiajia Jiang
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Jun Xu
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Kunkun Hu
- Wuhan CATUG Biotechnology, Wuhan 430074, China
| | - Meiling Xu
- Wuhan CATUG Biotechnology, Wuhan 430074, China
| | - Mengjie Liu
- Wuhan CATUG Biotechnology, Wuhan 430074, China
| | - Mengfei Sun
- CATUG Biotechnology, Suzhou 215000, China
- CATUG Life Technology, Suzhou 215000, China
| | - Lin Jin
- CATUG Biotechnology, Suzhou 215000, China
- Wuhan CATUG Biotechnology, Wuhan 430074, China
- CATUG Inc, Cambridge, MA 02141, United States
- CATUG Life Technology, Suzhou 215000, China
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3
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Islam A, Chakraborty A, Sarker AH, Aryal UK, Pan L, Sharma G, Boldogh I, Hazra T. Site-specific acetylation of polynucleotide kinase 3'-phosphatase regulates its distinct role in DNA repair pathways. Nucleic Acids Res 2024; 52:2416-2433. [PMID: 38224455 PMCID: PMC10954452 DOI: 10.1093/nar/gkae002] [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: 09/05/2023] [Revised: 12/21/2023] [Accepted: 01/01/2024] [Indexed: 01/16/2024] Open
Abstract
Mammalian polynucleotide kinase 3'-phosphatase (PNKP), a DNA end-processing enzyme with 3'-phosphatase and 5'-kinase activities, is involved in multiple DNA repair pathways, including base excision (BER), single-strand break (SSBR), and double-strand break repair (DSBR). However, little is known as to how PNKP functions in such diverse repair processes. Here we report that PNKP is acetylated at K142 (AcK142) by p300 constitutively but at K226 (AcK226) by CBP, only after DSB induction. Co-immunoprecipitation analysis using AcK142 or AcK226 PNKP-specific antibodies showed that AcK142-PNKP associates only with BER/SSBR, and AcK226 PNKP with DSBR proteins. Despite the modest effect of acetylation on PNKP's enzymatic activity in vitro, cells expressing non-acetylable PNKP (K142R or K226R) accumulated DNA damage in transcribed genes. Intriguingly, in striatal neuronal cells of a Huntington's Disease (HD)-based mouse model, K142, but not K226, was acetylated. This is consistent with the reported degradation of CBP, but not p300, in HD cells. Moreover, transcribed genomes of HD cells progressively accumulated DSBs. Chromatin-immunoprecipitation analysis demonstrated the association of Ac-PNKP with the transcribed genes, consistent with PNKP's role in transcription-coupled repair. Thus, our findings demonstrate that acetylation at two lysine residues, located in different domains of PNKP, regulates its distinct role in BER/SSBR versus DSBR.
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Affiliation(s)
- Azharul Islam
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Altaf H Sarker
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Uma K Aryal
- Purdue Proteomics Facility, Bindley Bioscience Center, Purdue University, IN 47907, USA
| | - Lang Pan
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Gulshan Sharma
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tapas Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
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4
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Milano L, Gautam A, Caldecott KW. DNA damage and transcription stress. Mol Cell 2024; 84:70-79. [PMID: 38103560 DOI: 10.1016/j.molcel.2023.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Genome damage and transcription are intimately linked. Tens to hundreds of thousands of DNA lesions arise in each cell each day, many of which can directly or indirectly impede transcription. Conversely, the process of gene expression is itself a source of endogenous DNA lesions as a result of the susceptibility of single-stranded DNA to damage, conflicts with the DNA replication machinery, and engagement by cells of topoisomerases and base excision repair enzymes to regulate the initiation and progression of gene transcription. Although such processes are tightly regulated and normally accurate, on occasion, they can become abortive and leave behind DNA breaks that can drive genome rearrangements, instability, or cell death.
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Affiliation(s)
- Larissa Milano
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Amit Gautam
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Keith W Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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5
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Caldecott KW. Causes and consequences of DNA single-strand breaks. Trends Biochem Sci 2024; 49:68-78. [PMID: 38040599 DOI: 10.1016/j.tibs.2023.11.001] [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: 08/07/2023] [Revised: 10/20/2023] [Accepted: 11/03/2023] [Indexed: 12/03/2023]
Abstract
DNA single-strand breaks (SSBs) are among the most common lesions arising in human cells, with tens to hundreds of thousands arising in each cell, each day. Cells have efficient mechanisms for the sensing and repair of these ubiquitous DNA lesions, but the failure of these processes to rapidly remove SSBs can lead to a variety of pathogenic outcomes. The threat posed by unrepaired SSBs is illustrated by the existence of at least six genetic diseases in which SSB repair (SSBR) is defective, all of which are characterised by neurodevelopmental and/or neurodegenerative pathology. Here, I review current understanding of how SSBs arise and impact on critical molecular processes, such as DNA replication and gene transcription, and their links to human disease.
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Affiliation(s)
- Keith W Caldecott
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, UK.
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6
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Wang J, Muste Sadurni M, Saponaro M. RNAPII response to transcription-blocking DNA lesions in mammalian cells. FEBS J 2023; 290:4382-4394. [PMID: 35731652 PMCID: PMC10952651 DOI: 10.1111/febs.16561] [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: 11/12/2021] [Revised: 05/15/2022] [Accepted: 06/21/2022] [Indexed: 09/21/2023]
Abstract
RNA polymerase II moves along genes to decode genetic information stored in the mammalian genome into messenger RNA and different forms of non-coding RNA. However, the transcription process is frequently challenged by DNA lesions caused by exogenous and endogenous insults, among which helix-distorting DNA lesions and double-stranded DNA breaks are particularly harmful for cell survival. In response to such DNA damage, RNA polymerase II transcription is regulated both locally and globally by multi-layer mechanisms, whereas transcription-blocking lesions are repaired before transcription can recover. Failure in DNA damage repair will cause genome instability and cell death. Although recent studies have expanded our understanding of RNA polymerase II regulation confronting DNA lesions, it is still not always clear what the direct contribution of RNA polymerase II is in the DNA damage repair processes. In this review, we focus on how RNA polymerase II and transcription are both repressed by transcription stalling lesions such as DNA-adducts and double strand breaks, as well as how they are actively regulated to support the cellular response to DNA damage and favour the repair of lesions.
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Affiliation(s)
- Jianming Wang
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic SciencesUniversity of BirminghamUK
| | - Martina Muste Sadurni
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic SciencesUniversity of BirminghamUK
| | - Marco Saponaro
- Transcription Associated Genome Instability Laboratory, Institute of Cancer and Genomic SciencesUniversity of BirminghamUK
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7
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Islam A, Chakraborty A, Sarker AH, Aryal UK, Sharma G, Boldogh I, Hazra T. Site-specific acetylation of polynucleotide kinase 3'-phosphatase (PNKP) regulates its distinct role in DNA repair pathways. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.21.545973. [PMID: 37645927 PMCID: PMC10461918 DOI: 10.1101/2023.06.21.545973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Mammalian polynucleotide kinase 3'-phosphatase (PNKP) is a dual-function DNA end-processing enzyme with 3'-phosphatase and 5'-kinase activities, which generate 3'-OH and 5'-phosphate termini respectively, as substrates for DNA polymerase and DNA ligase to complete DNA repair. PNKP is thus involved in multiple DNA repair pathways, including base excision (BER), single-strand break (SSBR), and double-strand break repair (DSBR). However, little is known as to how PNKP functions in such diverse repair processes, which involve distinct sets of proteins. In this study, we report that PNKP is acetylated at two lysine (K142 and K226) residues. While K142 (AcK142) is constitutively acetylated by p300, CBP acetylates K226 (AcK226) only after DSB induction. Co-immunoprecipitation analysis using antibodies specific for PNKP peptides containing AcK142 or AcK226 of PNKP showed that AcK142-PNKP associates only with BER/SSBR, and AcK226 PNKP only with DSBR proteins. Although acetylation at these residues did not significantly affect the enzymatic activity of PNKP in vitro, cells expressing nonacetylable PNKP (K142R or K226R) accumulated DNA damage, specifically in transcribed genes. Intriguingly, in striatal neuronal cells of a Huntington's Disease (HD)-based mouse model, K142, but not K226, was acetylated. This observation is consistent with the reported degradation of CBP but not p300 in HD cells. Moreover, genomes of HD cells progressively accumulated DSBs specifically in the transcribed genes. Chromatin-immunoprecipitation analysis using anti-AcK142 or anti-AcK226 antibodies demonstrated an association of Ac-PNKP with the transcribed genes, consistent with PNKP's role in transcription-coupled repair. Thus, our findings collectively demonstrate that acetylation at two lysine residues located in different domains of PNKP regulates its functionally distinct role in BER/SSBR vs. DSBR.
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Affiliation(s)
- Azharul Islam
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Altaf H Sarker
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Uma K Aryal
- Purdue Proteomics Facility, Bindley Bioscience Center, Purdue University, IN 47907, USA
| | - Gulshan Sharma
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tapas Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
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8
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Su M, Lien J, Anilao A, Guo T. Enhanced Single-Strand Breaks of a Nucleic Acid by Gold Nanoparticles under X-ray Irradiation. J Phys Chem Lett 2023; 14:1214-1221. [PMID: 36716218 DOI: 10.1021/acs.jpclett.2c03885] [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: 06/18/2023]
Abstract
The hydroxyl radical concentration-dependent yield of single-strand breaks (SSBs), obtained through correction of scavenging and hindrance effects caused by gold nanoparticles (AuNPs), for fluorophore- and quencher-labeled DNA on AuNPs was 10 times that of free DNA based on fluorescence measurements of X-ray-irradiated DNA on AuNPs. By comparing the fluorescence data that revealed the number of SSBs with the results of mass spectrometry measurements that detected the total damage to DNA, we found that SSBs dominated DNA damage for DNA on AuNPs whereas non-SSB damage dominated for free DNA. The yield of RNA SSBs under X-ray irradiation was similar to that of DNA in the presence of AuNPs, whereas free RNA was more resistive to radiation than DNA. These results indicated the enhanced SSBs were likely catalyzed through the conversion from nucleobase damage to SSBs by AuNPs. The outcome of this work impacts materials and environmental science, sensing, nanotechnology, biology, and medicine.
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Affiliation(s)
- Mengqi Su
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Jennifer Lien
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Auddy Anilao
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Ting Guo
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
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9
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Role of Histone Tails and Single Strand DNA Breaks in Nucleosomal Arrest of RNA Polymerase. Int J Mol Sci 2023; 24:ijms24032295. [PMID: 36768621 PMCID: PMC9917218 DOI: 10.3390/ijms24032295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/13/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
Transcription through nucleosomes by RNA polymerases (RNAP) is accompanied by formation of small intranucleosomal DNA loops (i-loops). The i-loops form more efficiently in the presence of single-strand breaks or gaps in a non-template DNA strand (NT-SSBs) and induce arrest of transcribing RNAP, thus allowing detection of NT-SSBs by the enzyme. Here we examined the role of histone tails and extranucleosomal NT-SSBs in i-loop formation and arrest of RNAP during transcription of promoter-proximal region of nucleosomal DNA. NT-SSBs present in linker DNA induce arrest of RNAP +1 to +15 bp in the nucleosome, suggesting formation of the i-loops; the arrest is more efficient in the presence of the histone tails. Consistently, DNA footprinting reveals formation of an i-loop after stalling RNAP at the position +2 and backtracking to position +1. The data suggest that histone tails and NT-SSBs present in linker DNA strongly facilitate formation of the i-loops during transcription through the promoter-proximal region of nucleosomal DNA.
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10
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Chakraborty A, Hazra TK. Highly Sensitive Radioactivity-Based DNA 3'-Phosphatase Activity Assay for Polynucleotide Kinase 3'-Phosphatase. Methods Mol Biol 2023; 2701:39-54. [PMID: 37574474 DOI: 10.1007/978-1-0716-3373-1_3] [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
Endogenous and exogenous genotoxic agents can generate various types of non-ligatable DNA ends at the site of strand break in the mammalian genome. If not repaired, such lesions will impede transcription and replication and can lead to various cellular pathologies. Among various "dirty" DNA ends, 3'-phosphate is one of the most abundant lesions generated in the mammalian cells. Polynucleotide kinase 3'-phosphatase (PNKP) is the major DNA end-processing enzyme for resolving 3'-phosphate termini in the mammalian cells, and thus, it is involved in DNA base excision repair (BER), single-strand break repair, and classical nonhomologous end joining (C-NHEJ)-mediated DNA double-strand break (DSB) repair. The 3'-OH ends generated following PNKP-mediated processing of 3'-P are utilized by a DNA polymerase to fill in the gap, and subsequently, the nick is sealed by a DNA ligase to complete the repair process. Here we describe two novel assay systems to detect phosphate release by PNKP's 3'-phosphatase activity and PNKP-mediated in vitro single-strand break repair with minimal repair components (PNKP, DNA polymerase, and DNA ligase) using either purified proteins or cell-free nuclear extracts from mammalian cells/tissues. These assays are highly reproducible and sensitive, and the researchers would be able to detect any significant difference in PNKP's 3'-phosphatase activity as well as PNKP-mediated single-strand break repair activity in diseased mammalian cells/tissues vs normal healthy controls.
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Affiliation(s)
- Anirban Chakraborty
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Tapas K Hazra
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Texas Medical Branch, Galveston, TX, USA.
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11
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Caldecott KW. DNA single-strand break repair and human genetic disease. Trends Cell Biol 2022; 32:733-745. [PMID: 35643889 DOI: 10.1016/j.tcb.2022.04.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 04/13/2022] [Accepted: 04/22/2022] [Indexed: 12/15/2022]
Abstract
DNA single-strand breaks (SSBs) are amongst the commonest DNA lesions arising in cells, with many tens of thousands induced in each cell each day. SSBs arise not only from exposure to intracellular and environmental genotoxins but also as intermediates of normal DNA metabolic processes, such as the removal of torsional stress in DNA by topoisomerase enzymes and the epigenetic regulation of gene expression by DNA base excision repair (BER). If not rapidly detected and repaired, SSBs can result in RNA polymerase stalling, DNA replication fork collapse, and hyperactivation of the SSB sensor protein poly(ADP-ribose) polymerase 1 (PARP1). The potential impact of unrepaired SSBs is illustrated by the existence of genetic diseases in which proteins involved in SSB repair (SSBR) are mutated, and which are typified by hereditary neurodevelopmental and/or neurodegenerative disease. Here, I review our current understanding of SSBR and its impact on human neurological disease, with a focus on recent developments and concepts.
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Affiliation(s)
- Keith W Caldecott
- Genome Damage and Stability Centre, School of Life Sciences, Science Park Road, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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12
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Structure of an Intranucleosomal DNA Loop That Senses DNA Damage during Transcription. Cells 2022; 11:cells11172678. [PMID: 36078089 PMCID: PMC9454427 DOI: 10.3390/cells11172678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Transcription through chromatin by RNA polymerase II (Pol II) is accompanied by the formation of small intranucleosomal DNA loops containing the enzyme (i-loops) that are involved in survival of core histones on the DNA and arrest of Pol II during the transcription of damaged DNA. However, the structures of i-loops have not been determined. Here, the structures of the intermediates formed during transcription through a nucleosome containing intact or damaged DNA were studied using biochemical approaches and electron microscopy. After RNA polymerase reaches position +24 from the nucleosomal boundary, the enzyme can backtrack to position +20, where DNA behind the enzyme recoils on the surface of the histone octamer, forming an i-loop that locks Pol II in the arrested state. Since the i-loop is formed more efficiently in the presence of SSBs positioned behind the transcribing enzyme, the loop could play a role in the transcription-coupled repair of DNA damage hidden in the chromatin structure.
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13
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Zhang P, Fischer A, Ouyang Y, Sohn YS, Nechushtai R, Zhang J, Tian H, Fan C, Willner I. Topologically switchable and gated transcription machinery. Chem Sci 2022; 13:10555-10565. [PMID: 36277654 PMCID: PMC9473513 DOI: 10.1039/d2sc01599d] [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: 03/19/2022] [Accepted: 08/17/2022] [Indexed: 11/21/2022] Open
Abstract
Three different topological barriers to switch transcription machineries were introduced including Sr2+-ion stabilized G-quadruplex units, T-A·T triplex structures and photoisomerizable azobenzene-nucleic acid blockers.
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Affiliation(s)
- Pu Zhang
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Amit Fischer
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yu Ouyang
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Yang Sung Sohn
- Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Rachel Nechushtai
- Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Junji Zhang
- Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - He Tian
- Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, National Center for Translational Medicine, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Itamar Willner
- Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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14
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Agapov A, Olina A, Kulbachinskiy A. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3018-3041. [PMID: 35323981 PMCID: PMC8989532 DOI: 10.1093/nar/gkac174] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 11/14/2022] Open
Abstract
Cellular DNA is continuously transcribed into RNA by multisubunit RNA polymerases (RNAPs). The continuity of transcription can be disrupted by DNA lesions that arise from the activities of cellular enzymes, reactions with endogenous and exogenous chemicals or irradiation. Here, we review available data on translesion RNA synthesis by multisubunit RNAPs from various domains of life, define common principles and variations in DNA damage sensing by RNAP, and consider existing controversies in the field of translesion transcription. Depending on the type of DNA lesion, it may be correctly bypassed by RNAP, or lead to transcriptional mutagenesis, or result in transcription stalling. Various lesions can affect the loading of the templating base into the active site of RNAP, or interfere with nucleotide binding and incorporation into RNA, or impair RNAP translocation. Stalled RNAP acts as a sensor of DNA damage during transcription-coupled repair. The outcome of DNA lesion recognition by RNAP depends on the interplay between multiple transcription and repair factors, which can stimulate RNAP bypass or increase RNAP stalling, and plays the central role in maintaining the DNA integrity. Unveiling the mechanisms of translesion transcription in various systems is thus instrumental for understanding molecular pathways underlying gene regulation and genome stability.
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Affiliation(s)
- Aleksei Agapov
- Correspondence may also be addressed to Aleksei Agapov. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
| | - Anna Olina
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute” Moscow 123182, Russia
| | - Andrey Kulbachinskiy
- To whom correspondence should be addressed. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
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15
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Adamowicz M, Hailstone R, Demin AA, Komulainen E, Hanzlikova H, Brazina J, Gautam A, Wells SE, Caldecott KW. XRCC1 protects transcription from toxic PARP1 activity during DNA base excision repair. Nat Cell Biol 2021; 23:1287-1298. [PMID: 34811483 PMCID: PMC8683375 DOI: 10.1038/s41556-021-00792-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/11/2021] [Indexed: 11/22/2022]
Abstract
Genetic defects in the repair of DNA single-strand breaks (SSBs) can result in neurological disease triggered by toxic activity of the single-strand-break sensor protein PARP1. However, the mechanism(s) by which this toxic PARP1 activity triggers cellular dysfunction are unclear. Here we show that human cells lacking XRCC1 fail to rapidly recover transcription following DNA base damage, a phenotype also observed in patient-derived fibroblasts with XRCC1 mutations and Xrcc1−/− mouse neurons. This defect is caused by excessive/aberrant PARP1 activity during DNA base excision repair, resulting from the loss of PARP1 regulation by XRCC1. We show that aberrant PARP1 activity suppresses transcriptional recovery during base excision repair by promoting excessive recruitment and activity of the ubiquitin protease USP3, which as a result reduces the level of monoubiquitinated histones important for normal transcriptional regulation. Importantly, inhibition and/or deletion of PARP1 or USP3 restores transcriptional recovery in XRCC1−/− cells, highlighting PARP1 and USP3 as possible therapeutic targets in neurological disease. Adamowicz et al. report that toxic PARP1 activity, induced by ataxia-associated mutations in XRCC1, impairs the recovery of global transcription during DNA base excision repair by promoting aberrant recruitment and activity of the histone ubiquitin protease USP3.
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Affiliation(s)
- Marek Adamowicz
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Richard Hailstone
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Annie A Demin
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Emilia Komulainen
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Hana Hanzlikova
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK.,Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Science, Prague, Czech Republic
| | - Jan Brazina
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Amit Gautam
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Sophie E Wells
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Keith W Caldecott
- Genome Damage and Stability Centre and Sussex Drug Discovery Centre, School of Life Sciences, University of Sussex, Brighton, UK. .,Department of Genome Dynamics, Institute of Molecular Genetics of the Czech Academy of Science, Prague, Czech Republic.
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16
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Chakraborty A, Tapryal N, Islam A, Mitra S, Hazra T. Transcription coupled base excision repair in mammalian cells: So little is known and so much to uncover. DNA Repair (Amst) 2021; 107:103204. [PMID: 34390916 DOI: 10.1016/j.dnarep.2021.103204] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/06/2021] [Accepted: 08/03/2021] [Indexed: 12/31/2022]
Abstract
Oxidized bases in the genome has been implicated in various human pathologies, including cancer, aging and neurological diseases. Their repair is initiated with excision by DNA glycosylases (DGs) in the base excision repair (BER) pathway. Among the five oxidized base-specific human DGs, OGG1 and NTH1 preferentially excise oxidized purines and pyrimidines, respectively, while NEILs remove both oxidized purines and pyrimidines. However, little is known about why cells possess multiple DGs with overlapping substrate specificities. Studies of the past decades revealed that some DGs are involved in repair of oxidized DNA base lesions in the actively transcribed regions. Preferential removal of lesions from the transcribed strands of active genes, called transcription-coupled repair (TCR), was discovered as a distinct sub-pathway of nucleotide excision repair; however, such repair of oxidized DNA bases had not been established until our recent demonstration of NEIL2's role in TC-BER of the nuclear genome. We have shown that NEIL2 forms a distinct transcriptionally active, repair proficient complex. More importantly, we for the first time reconstituted TC-BER using purified components. These studies are important for characterizing critical requirement for the process. However, because NEIL2 cannot remove all types of oxidized bases, it is unlikely to be the only DNA glycosylase involved in TC-BER. Hence, we postulate TC-BER process to be universally involved in maintaining the functional integrity of active genes, especially in post-mitotic, non-growing cells. We further postulate that abnormal bases (e.g., uracil), and alkylated and other small DNA base adducts are also repaired via TC-BER. In this review, we have provided an overview of the various aspects of TC-BER in mammalian cells with the hope of generating significant interest of many researchers in the field. Further studies aimed at better understanding the mechanistic aspects of TC-BER could help elucidate the linkage of TC-BER deficiency to various human pathologies.
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Affiliation(s)
- Anirban Chakraborty
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Nisha Tapryal
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Azharul Islam
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sankar Mitra
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Tapas Hazra
- Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA.
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17
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Komulainen E, Badman J, Rey S, Rulten S, Ju L, Fennell K, Kalasova I, Ilievova K, McKinnon PJ, Hanzlikova H, Staras K, Caldecott KW. Parp1 hyperactivity couples DNA breaks to aberrant neuronal calcium signalling and lethal seizures. EMBO Rep 2021; 22:e51851. [PMID: 33932076 PMCID: PMC8097344 DOI: 10.15252/embr.202051851] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 12/21/2022] Open
Abstract
Defects in DNA single-strand break repair (SSBR) are linked with neurological dysfunction but the underlying mechanisms remain poorly understood. Here, we show that hyperactivity of the DNA strand break sensor protein Parp1 in mice in which the central SSBR protein Xrcc1 is conditionally deleted (Xrcc1Nes-Cre ) results in lethal seizures and shortened lifespan. Using electrophysiological recording and synaptic imaging approaches, we demonstrate that aberrant Parp1 activation triggers seizure-like activity in Xrcc1-defective hippocampus ex vivo and deregulated presynaptic calcium signalling in isolated hippocampal neurons in vitro. Moreover, we show that these defects are prevented by Parp1 inhibition or deletion and, in the case of Parp1 deletion, that the lifespan of Xrcc1Nes-Cre mice is greatly extended. This is the first demonstration that lethal seizures can be triggered by aberrant Parp1 activity at unrepaired SSBs, highlighting PARP inhibition as a possible therapeutic approach in hereditary neurological disease.
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Affiliation(s)
- Emilia Komulainen
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Jack Badman
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Stephanie Rey
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Stuart Rulten
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Limei Ju
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
| | - Kate Fennell
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Ilona Kalasova
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Kristyna Ilievova
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Peter J McKinnon
- Department of GeneticsSt Jude Children’s Research HospitalMemphisTNUSA
| | - Hana Hanzlikova
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Kevin Staras
- Sussex NeuroscienceSchool of Life SciencesUniversity of SussexBrightonUK
| | - Keith W Caldecott
- Genome Damage and Stability CentreSchool of Life SciencesUniversity of SussexBrightonUK
- Department of Genome DynamicsInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
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18
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Pipathsouk A, Belotserkovskii BP, Hanawalt PC. When transcription goes on Holliday: Double Holliday junctions block RNA polymerase II transcription in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1860:282-288. [PMID: 27923713 DOI: 10.1016/j.bbagrm.2016.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/22/2016] [Accepted: 12/02/2016] [Indexed: 01/04/2023]
Abstract
Non-canonical DNA structures can obstruct transcription. This transcription blockage could have various biological consequences, including genomic instability and gratuitous transcription-coupled repair. Among potential structures causing transcription blockage are Holliday junctions (HJs), which can be generated as intermediates in homologous recombination or during processing of stalled replication forks. Of particular interest is the double Holliday junction (DHJ), which contains two HJs. Topological considerations impose the constraint that the total number of helical turns in the DNA duplexes between the junctions cannot be altered as long as the flanking DNA duplexes are intact. Thus, the DHJ structure should strongly resist transient unwinding during transcription; consequently, it is predicted to cause significantly stronger blockage than single HJ structures. The patterns of transcription blockage obtained for RNA polymerase II transcription in HeLa cell nuclear extracts were in accordance with this prediction. However, we did not detect transcription blockage with purified T7 phage RNA polymerase; we discuss a possible explanation for this difference. In general, our findings implicate naturally occurring Holliday junctions in transcription arrest.
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Affiliation(s)
- Anne Pipathsouk
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | - Philip C Hanawalt
- Department of Biology, Stanford University, Stanford, CA 94305, USA.
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19
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Chakraborty A, Tapryal N, Venkova T, Horikoshi N, Pandita RK, Sarker AH, Sarkar PS, Pandita TK, Hazra TK. Classical non-homologous end-joining pathway utilizes nascent RNA for error-free double-strand break repair of transcribed genes. Nat Commun 2016; 7:13049. [PMID: 27703167 PMCID: PMC5059474 DOI: 10.1038/ncomms13049] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/30/2016] [Indexed: 12/30/2022] Open
Abstract
DNA double-strand breaks (DSBs) leading to loss of nucleotides in the transcribed region can be lethal. Classical non-homologous end-joining (C-NHEJ) is the dominant pathway for DSB repair (DSBR) in adult mammalian cells. Here we report that during such DSBR, mammalian C-NHEJ proteins form a multiprotein complex with RNA polymerase II and preferentially associate with the transcribed genes after DSB induction. Depletion of C-NHEJ factors significantly abrogates DSBR in transcribed but not in non-transcribed genes. We hypothesized that nascent RNA can serve as a template for restoring the missing sequences, thus allowing error-free DSBR. We indeed found pre-mRNA in the C-NHEJ complex. Finally, when a DSB-containing plasmid with several nucleotides deleted within the E. coli lacZ gene was allowed time to repair in lacZ-expressing mammalian cells, a functional lacZ plasmid could be recovered from control but not C-NHEJ factor-depleted cells, providing important mechanistic insights into C-NHEJ-mediated error-free DSBR of the transcribed genome. Most adult mammalian cells prefer to repair double-strand DNA breaks though the classical nonhomologous end-joining pathway. Here the authors present evidence that a nascent RNA transcript can serve as a template to facilitate error-free repair.
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Affiliation(s)
- Anirban Chakraborty
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nisha Tapryal
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tatiana Venkova
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Nobuo Horikoshi
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Raj K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Altaf H Sarker
- Division of Life Sciences, Department of Cancer and DNA Damage Responses, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Partha S Sarkar
- Department of Neurology and Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Tej K Pandita
- Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, Texas 77030, USA
| | - Tapas K Hazra
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA
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20
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Xu L, Wang W, Chong J, Shin JH, Xu J, Wang D. RNA polymerase II transcriptional fidelity control and its functional interplay with DNA modifications. Crit Rev Biochem Mol Biol 2015; 50:503-19. [PMID: 26392149 DOI: 10.3109/10409238.2015.1087960] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Accurate genetic information transfer is essential for life. As a key enzyme involved in the first step of gene expression, RNA polymerase II (Pol II) must maintain high transcriptional fidelity while it reads along DNA template and synthesizes RNA transcript in a stepwise manner during transcription elongation. DNA lesions or modifications may lead to significant changes in transcriptional fidelity or transcription elongation dynamics. In this review, we will summarize recent progress toward understanding the molecular basis of RNA Pol II transcriptional fidelity control and impacts of DNA lesions and modifications on Pol II transcription elongation.
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Affiliation(s)
- Liang Xu
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
| | - Wei Wang
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
| | - Jenny Chong
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
| | - Ji Hyun Shin
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
| | - Jun Xu
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
| | - Dong Wang
- a Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California San Diego , La Jolla , CA , USA
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21
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Khodursky A, Guzmán EC, Hanawalt PC. Thymineless Death Lives On: New Insights into a Classic Phenomenon. Annu Rev Microbiol 2015; 69:247-63. [PMID: 26253395 DOI: 10.1146/annurev-micro-092412-155749] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The primary mechanisms by which bacteria lose viability when deprived of thymine have been elusive for over half a century. Early research focused on stalled replication forks and the deleterious effects of uracil incorporation into DNA from thymidine-deficient nucleotide pools. The initiation of the replication cycle and origin-proximal DNA degradation during thymine starvation have now been quantified via whole-genome microarrays and other approaches. These advances have fostered innovative models and informative experiments in bacteria since this topic was last reviewed. Given that thymineless death is similar in mammalian cells and that certain antibacterial and chemotherapeutic drugs elicit thymine deficiency, a mechanistic understanding of this phenomenon might have valuable biomedical applications.
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Affiliation(s)
- Arkady Khodursky
- Biotechnology Institute and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, St. Paul, Minnesota 55108;
| | - Elena C Guzmán
- Departamento de Bioquímica Biología Molecular y Genética, Universidad de Extremadura, 06071 Badajoz, Spain;
| | - Philip C Hanawalt
- Department of Biology, Stanford University, Stanford, California 94305;
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22
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Pandey S, Ogloblina AM, Belotserkovskii BP, Dolinnaya NG, Yakubovskaya MG, Mirkin SM, Hanawalt PC. Transcription blockage by stable H-DNA analogs in vitro. Nucleic Acids Res 2015; 43:6994-7004. [PMID: 26101261 PMCID: PMC4538819 DOI: 10.1093/nar/gkv622] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/03/2015] [Indexed: 11/14/2022] Open
Abstract
DNA sequences that can form unusual secondary structures are implicated in regulating gene expression and causing genomic instability. H-palindromes are an important class of such DNA sequences that can form an intramolecular triplex structure, H-DNA. Within an H-palindrome, the H-DNA and canonical B-DNA are in a dynamic equilibrium that shifts toward H-DNA with increased negative supercoiling. The interplay between H- and B-DNA and the fact that the process of transcription affects supercoiling makes it difficult to elucidate the effects of H-DNA upon transcription. We constructed a stable structural analog of H-DNA that cannot flip into B-DNA, and studied the effects of this structure on transcription by T7 RNA polymerase in vitro. We found multiple transcription blockage sites adjacent to and within sequences engaged in this triplex structure. Triplex-mediated transcription blockage varied significantly with changes in ambient conditions: it was exacerbated in the presence of Mn(2+) or by increased concentrations of K(+) and Li(+). Analysis of the detailed pattern of the blockage suggests that RNA polymerase is sterically hindered by H-DNA and has difficulties in unwinding triplex DNA. The implications of these findings for the biological roles of triple-stranded DNA structures are discussed.
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Affiliation(s)
- Shristi Pandey
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | | | - Nina G Dolinnaya
- Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | | | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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23
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Hahn MA, Szabó PE, Pfeifer GP. 5-Hydroxymethylcytosine: a stable or transient DNA modification? Genomics 2014; 104:314-23. [PMID: 25181633 DOI: 10.1016/j.ygeno.2014.08.015] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/13/2014] [Accepted: 08/15/2014] [Indexed: 12/16/2022]
Abstract
The DNA base 5-hydroxymethylcytosine (5hmC) is produced by enzymatic oxidation of 5-methylcytosine (5mC) by 5mC oxidases (the Tet proteins). Since 5hmC is recognized poorly by DNA methyltransferases, DNA methylation may be lost at 5hmC sites during DNA replication. In addition, 5hmC can be oxidized further by Tet proteins and converted to 5-formylcytosine and 5-carboxylcytosine, two bases that can be removed from DNA by base excision repair. The completed pathway represents a replication-independent DNA demethylation cycle. However, the DNA base 5hmC is also known to be rather stable and occurs at substantial levels, for example in the brain, suggesting that it represents an epigenetic mark by itself that may regulate chromatin structure and transcription. Focusing on a few well-studied tissues and developmental stages, we discuss the opposing views of 5hmC as a transient intermediate in DNA demethylation and as a modified DNA base with an instructive role.
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Affiliation(s)
- Maria A Hahn
- Beckman Research Institute, City of Hope, Duarte CA 91010, USA
| | - Piroska E Szabó
- Beckman Research Institute, City of Hope, Duarte CA 91010, USA
| | - Gerd P Pfeifer
- Beckman Research Institute, City of Hope, Duarte CA 91010, USA.
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24
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Xu L, Da L, Plouffe SW, Chong J, Kool E, Wang D. Molecular basis of transcriptional fidelity and DNA lesion-induced transcriptional mutagenesis. DNA Repair (Amst) 2014; 19:71-83. [PMID: 24767259 DOI: 10.1016/j.dnarep.2014.03.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Maintaining high transcriptional fidelity is essential for life. Some DNA lesions lead to significant changes in transcriptional fidelity. In this review, we will summarize recent progress towards understanding the molecular basis of RNA polymerase II (Pol II) transcriptional fidelity and DNA lesion-induced transcriptional mutagenesis. In particular, we will focus on the three key checkpoint steps of controlling Pol II transcriptional fidelity: insertion (specific nucleotide selection and incorporation), extension (differentiation of RNA transcript extension of a matched over mismatched 3'-RNA terminus), and proofreading (preferential removal of misincorporated nucleotides from the 3'-RNA end). We will also discuss some novel insights into the molecular basis and chemical perspectives of controlling Pol II transcriptional fidelity through structural, computational, and chemical biology approaches.
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Affiliation(s)
- Liang Xu
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA 92093-0625, United States
| | - Linati Da
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA 92093-0625, United States
| | - Steven W Plouffe
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA 92093-0625, United States
| | - Jenny Chong
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA 92093-0625, United States
| | - Eric Kool
- Department of Chemistry, Stanford University, Stanford, CA 94305-5080, United States.
| | - Dong Wang
- Skaggs School of Pharmacy and Pharmaceutical Science, University of California San Diego, La Jolla, CA 92093-0625, United States.
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25
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Belotserkovskii BP, Mirkin SM, Hanawalt PC. DNA sequences that interfere with transcription: implications for genome function and stability. Chem Rev 2013; 113:8620-37. [PMID: 23972098 DOI: 10.1021/cr400078y] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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26
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Khobta A, Epe B. Repair of oxidatively generated DNA damage in Cockayne syndrome. Mech Ageing Dev 2013; 134:253-60. [PMID: 23518175 DOI: 10.1016/j.mad.2013.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/12/2013] [Accepted: 03/01/2013] [Indexed: 11/16/2022]
Abstract
Defects in the repair of endogenously (especially oxidatively) generated DNA modifications and the resulting genetic instability can potentially explain the clinical symptoms of Cockayne syndrome (CS), a hereditary disease characterized by developmental defects and neurological degeneration. In this review, we describe the evidence for the involvement of CSA and CSB proteins, which are mutated in most of the CS patients, in the repair and processing of DNA damage induced by reactive oxygen species and the implications for the induction of cell death and mutations. Taken together, the data demonstrate that CSA and CSB, in addition to their established role in transcription-coupled nucleotide excision repair, can modulate the base excision repair (BER) of oxidized DNA bases both directly (by interaction with BER proteins) and indirectly (by modulating the expression of the DNA repair genes). Both nuclear and mitochondrial DNA repair is affected by mutations in CSA and CSB genes. However, the observed retardations of repair and the resulting accumulation of unrepaired endogenously generated DNA lesions are often mild, thus pointing to the relevance of additional roles of the CS proteins, e.g. in the mitochondrial response to oxidatively generated DNA damage and in the maintenance of gene transcription.
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Affiliation(s)
- Andriy Khobta
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55099 Mainz, Germany.
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27
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Belotserkovskii BP, Neil AJ, Saleh SS, Shin JHS, Mirkin SM, Hanawalt PC. 130 Transcription blockage by single-strand breaks in various sequences and the general model for transcription blockage by R-loop formation. J Biomol Struct Dyn 2013. [DOI: 10.1080/07391102.2013.786372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Belotserkovskii BP, Neil AJ, Saleh SS, Shin JHS, Mirkin SM, Hanawalt PC. Transcription blockage by homopurine DNA sequences: role of sequence composition and single-strand breaks. Nucleic Acids Res 2012; 41:1817-28. [PMID: 23275544 PMCID: PMC3561996 DOI: 10.1093/nar/gks1333] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The ability of DNA to adopt non-canonical structures can affect transcription and has broad implications for genome functioning. We have recently reported that guanine-rich (G-rich) homopurine-homopyrimidine sequences cause significant blockage of transcription in vitro in a strictly orientation-dependent manner: when the G-rich strand serves as the non-template strand [Belotserkovskii et al. (2010) Mechanisms and implications of transcription blockage by guanine-rich DNA sequences., Proc. Natl Acad. Sci. USA, 107, 12816–12821]. We have now systematically studied the effect of the sequence composition and single-stranded breaks on this blockage. Although substitution of guanine by any other base reduced the blockage, cytosine and thymine reduced the blockage more significantly than adenine substitutions, affirming the importance of both G-richness and the homopurine-homopyrimidine character of the sequence for this effect. A single-strand break in the non-template strand adjacent to the G-rich stretch dramatically increased the blockage. Breaks in the non-template strand result in much weaker blockage signals extending downstream from the break even in the absence of the G-rich stretch. Our combined data support the notion that transcription blockage at homopurine-homopyrimidine sequences is caused by R-loop formation.
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