1
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Lee Y, Gu S, Al-Hashimi HM. Insights into the A-C mismatch conformational ensemble in duplex DNA and its role in genetic processes through a structure-based review. J Mol Biol 2024:168710. [PMID: 39009073 DOI: 10.1016/j.jmb.2024.168710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 07/10/2024] [Accepted: 07/10/2024] [Indexed: 07/17/2024]
Abstract
Knowing the conformational ensembles formed by mismatches is crucial for understanding how they are generated and repaired and how they contribute to genomic instability. Here, we review structural and energetic studies of the A-C mismatch in duplex DNA and use the information to identify critical conformational states in its ensemble and their significance in genetic processes. In the 1970s, Topal and Fresco proposed the A-C wobble stabilized by two hydrogen bonds, one requiring protonation of adenine-N1. Subsequent NMR and X-ray crystallography studies showed that the protonated A-C wobble was in dynamic equilibrium with a neutral inverted wobble. The mismatch was shown to destabilize duplex DNA in a sequence- and pH-dependent manner by 2.4-3.8 kcal/mol and to have an apparent pKa ranging between 7.2 and 7.7. The A-C mismatch conformational repertoire expanded as structures were determined for damaged and protein-bound DNA. These structures included Watson-Crick-like conformations forming through tautomerization of the bases that drive replication errors, the reverse wobble forming through rotation of the entire nucleotide proposed to increase the fidelity of DNA replication, and the Hoogsteen base-pair forming through the flipping of the adenine base which explained the unusual specificity of DNA polymerases that bypass DNA damage. Thus, the A-C mismatch ensemble encompasses various conformational states that can be selectively stabilized in response to environmental changes such as pH shifts, intermolecular interactions, and chemical modifications, and these adaptations facilitate critical biological processes. This review also highlights the utility of existing 3D structures to build ensemble models for nucleic acid motifs.
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Affiliation(s)
- Yeongjoon Lee
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States
| | - Stephanie Gu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States.
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2
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Kisby GE, Wilson DM, Spencer PS. Introducing the Role of Genotoxicity in Neurodegenerative Diseases and Neuropsychiatric Disorders. Int J Mol Sci 2024; 25:7221. [PMID: 39000326 PMCID: PMC11241460 DOI: 10.3390/ijms25137221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024] Open
Abstract
Decades of research have identified genetic and environmental factors involved in age-related neurodegenerative diseases and, to a lesser extent, neuropsychiatric disorders. Genomic instability, i.e., the loss of genome integrity, is a common feature among both neurodegenerative (mayo-trophic lateral sclerosis, Parkinson's disease, Alzheimer's disease) and psychiatric (schizophrenia, autism, bipolar depression) disorders. Genomic instability is associated with the accumulation of persistent DNA damage and the activation of DNA damage response (DDR) pathways, as well as pathologic neuronal cell loss or senescence. Typically, DDR signaling ensures that genomic and proteomic homeostasis are maintained in both dividing cells, including neural progenitors, and post-mitotic neurons. However, dysregulation of these protective responses, in part due to aging or environmental insults, contributes to the progressive development of neurodegenerative and/or psychiatric disorders. In this Special Issue, we introduce and highlight the overlap between neurodegenerative diseases and neuropsychiatric disorders, as well as the emerging clinical, genomic, and molecular evidence for the contributions of DNA damage and aberrant DNA repair. Our goal is to illuminate the importance of this subject to uncover possible treatment and prevention strategies for relevant devastating brain diseases.
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Affiliation(s)
- Glen E. Kisby
- Department of Biomedical Sciences, College of Osteopathic Medicine of Pacific Northwest, Western University of Health Sciences, Lebanon, OR 97355, USA
| | - David M. Wilson
- Biomedical Research Institute, BIOMED, Hasselt University, 3500 Hasselt, Belgium;
| | - Peter S. Spencer
- Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Sciences University (OHSU), Portland, OR 97239, USA
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3
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Dinep-Schneider O, Appiah E, Dapper A, Patterson S, Vermulst M, Gout JF. Effects of the glyphosate-based herbicide Roundup on C. elegans and S. cerevisiae mortality, reproduction, and transcription fidelity. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 356:124203. [PMID: 38830529 DOI: 10.1016/j.envpol.2024.124203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024]
Abstract
Glyphosate-based weed killers such as Roundup have been implicated in detrimental effects on single- and multicellular eukaryotic model organism health and longevity. However, the mode(s) of action for these effects are currently unknown. In this study, we investigate the impact of exposure to Roundup on two model organisms: Saccharomyces cerevisiae and Caenorhabditis elegans and test the hypothesis that exposure to Roundup decreases transcription fidelity. Population growth assays and motility assays were performed in order to determine the phenotypic effects of Roundup exposure. We also used Rolling-Circle Amplification RNA sequencing to quantify the impact of exposure to Roundup on transcription fidelity in these two model organisms. Our results show that exposure to the glyphosate-based herbicide Roundup increases mortality, reduces reproduction, and increases transcription error rates in C. elegans and S. cerevisiae. We suggest that these effects may be due in part to the involvement of inflammation and oxidative stress, conditions which may also contribute to increases in transcription error rates.
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Affiliation(s)
| | - Eastilan Appiah
- Department of Computer Science and Engineering, Computational Biology, Mississippi State University, Starkville MS
| | - Amy Dapper
- Department of Biology, Mississippi State University, Starkville MS
| | - Sarah Patterson
- Department of Computer Science and Engineering, Computational Biology, Mississippi State University, Starkville MS
| | - Marc Vermulst
- University of Southern California, Leonard Davis School of Gerontology, Los Angeles, CA 90089
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4
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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: implications for the fidelity of transcription and CRISPR/Cas9 gene editing. Nucleic Acids Res 2024; 52:2672-2685. [PMID: 38281263 PMCID: PMC10954477 DOI: 10.1093/nar/gkae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/02/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024] Open
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G·T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R1ρ experiments, we show that dG·rU and dT·rG mismatches in two RNA:DNA hybrids transiently form tautomeric (Genol·T/U $ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}}$ G·Tenol/Uenol) and anionic (G·T-/U-) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG·rU- formed with a ten-fold higher propensity relative to dT-·rG and dG·dT- and this could be attributed to the lower pKa (ΔpKa ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G·T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G·U versus G·T, and indicate that anionic Watson-Crick-like G·U- could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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Affiliation(s)
- Or Szekely
- Department of Biology, Duke University, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University, Durham, NC 27710, USA
| | | | - Stephanie Gu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Akanksha Manghrani
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Serafima Guseva
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
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5
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Ren P, Zhang J, Vijg J. Somatic mutations in aging and disease. GeroScience 2024:10.1007/s11357-024-01113-3. [PMID: 38488948 DOI: 10.1007/s11357-024-01113-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Time always leaves its mark, and our genome is no exception. Mutations in the genome of somatic cells were first hypothesized to be the cause of aging in the 1950s, shortly after the molecular structure of DNA had been described. Somatic mutation theories of aging are based on the fact that mutations in DNA as the ultimate template for all cellular functions are irreversible. However, it took until the 1990s to develop the methods to test if DNA mutations accumulate with age in different organs and tissues and estimate the severity of the problem. By now, numerous studies have documented the accumulation of somatic mutations with age in normal cells and tissues of mice, humans, and other animals, showing clock-like mutational signatures that provide information on the underlying causes of the mutations. In this review, we will first briefly discuss the recent advances in next-generation sequencing that now allow quantitative analysis of somatic mutations. Second, we will provide evidence that the mutation rate differs between cell types, with a focus on differences between germline and somatic mutation rate. Third, we will discuss somatic mutational signatures as measures of aging, environmental exposure, and activities of DNA repair processes. Fourth, we will explain the concept of clonally amplified somatic mutations, with a focus on clonal hematopoiesis. Fifth, we will briefly discuss somatic mutations in the transcriptome and in our other genome, i.e., the genome of mitochondria. We will end with a brief discussion of a possible causal contribution of somatic mutations to the aging process.
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Affiliation(s)
- Peijun Ren
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Jie Zhang
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jan Vijg
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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6
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Gao S, Hou P, Oh J, Wang D, Greenberg MM. Molecular Mechanism of RNA Polymerase II Transcriptional Mutagenesis by the Epimerizable DNA Lesion, Fapy·dG. J Am Chem Soc 2024; 146:6274-6282. [PMID: 38393762 PMCID: PMC10932878 DOI: 10.1021/jacs.3c14476] [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: 02/25/2024]
Abstract
Oxidative DNA lesions cause significant detrimental effects on a living species. Two major DNA lesions resulting from dG oxidation, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo) and formamidopyrimidine (Fapy·dG), are produced from a common chemical intermediate. Fapy·dG is formed in comparable yields under oxygen-deficient conditions. Replicative bypass of Fapy·dG in human cells is more mutagenic than that of 8-OxodGuo. Despite the biological importance of transcriptional mutagenesis, there are no reports of the effects of Fapy·dG on RNA polymerase II (Pol II) activity. Here we perform comprehensive kinetic studies to investigate the impact of Fapy·dG on three key transcriptional fidelity checkpoint steps by Pol II: insertion, extension, and proofreading steps. The ratios of error-free versus error-prone incorporation opposite Fapy·dG are significantly reduced in comparison with undamaged dG. Similarly, Fapy·dG:A mispair is extended with comparable efficiency as that of the error-free, Fapy·dG:C base pair. The α- and β-configurational isomers of Fapy·dG have distinct effects on Pol II insertion and extension. Pol II can preferentially cleave error-prone products by proofreading. To further understand the structural basis of transcription processing of Fapy·dG, five different structures were solved, including Fapy·dG template-loading state (apo), error-free cytidine triphosphate (CTP) binding state (prechemistry), error-prone ATP binding state (prechemistry), error-free Fapy·dG:C product state (postchemistry), and error-prone Fapy·dG:A product state (postchemistry), revealing distinctive nucleotide binding and product states. Taken together, our study provides a comprehensive mechanistic framework for better understanding how Fapy·dG lesions impact transcription and subsequent pathological consequences.
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Affiliation(s)
- Shijun Gao
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Peini Hou
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Regulatory Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Marc M Greenberg
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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7
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Verheijen BM, Chung C, Thompson B, Kim H, Nakahara A, Anink JJ, Mills JD, Lee JH, Aronica E, Oyanagi K, Kakita A, Gout JF, Vermulst M. The cycad genotoxin methylazoxymethanol, linked to Guam ALS/PDC, induces transcriptional mutagenesis. Acta Neuropathol Commun 2024; 12:30. [PMID: 38383591 PMCID: PMC10882831 DOI: 10.1186/s40478-024-01725-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 02/23/2024] Open
Affiliation(s)
- Bert M Verheijen
- School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA.
- Department of Neuroscience, Maastricht University, Maastricht, The Netherlands.
| | - Claire Chung
- School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ben Thompson
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hyunjin Kim
- Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Asa Nakahara
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Jasper J Anink
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - James D Mills
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter, SL9 0RJ, UK
| | - Jeong H Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Kiyomitsu Oyanagi
- Division of Neuropathology, Department of Brain Disease Research, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Jean-Francois Gout
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Marc Vermulst
- School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
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8
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Burkewitz K. Hitting the brakes on transcription to extend lifespan. Trends Genet 2023; 39:889-891. [PMID: 37574379 PMCID: PMC10841265 DOI: 10.1016/j.tig.2023.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 08/15/2023]
Abstract
In aged animals from worms to humans, transcriptional elongation rates are faster, leading to changes in transcript quality and alternative splicing. Recent work by Debès et al. shows how interventions that slow elongation rates, such as mutating RNA polymerase II (Pol II) or increasing nucleosome density to impose transcriptional 'traffic', delay senescence and promote longevity.
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Affiliation(s)
- Kristopher Burkewitz
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.
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9
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Tyshkovskiy A, Zhang S, Gladyshev VN. Accelerated transcriptional elongation during aging impairs longevity. Cell Res 2023; 33:817-818. [PMID: 37253838 PMCID: PMC10624826 DOI: 10.1038/s41422-023-00829-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Affiliation(s)
- Alexander Tyshkovskiy
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sirui Zhang
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Broad Institute, Cambridge, MA, USA.
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10
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Wysocki R, Rodrigues JI, Litwin I, Tamás MJ. Mechanisms of genotoxicity and proteotoxicity induced by the metalloids arsenic and antimony. Cell Mol Life Sci 2023; 80:342. [PMID: 37904059 PMCID: PMC10616229 DOI: 10.1007/s00018-023-04992-5] [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: 06/23/2023] [Revised: 09/12/2023] [Accepted: 09/29/2023] [Indexed: 11/01/2023]
Abstract
Arsenic and antimony are metalloids with profound effects on biological systems and human health. Both elements are toxic to cells and organisms, and exposure is associated with several pathological conditions including cancer and neurodegenerative disorders. At the same time, arsenic- and antimony-containing compounds are used in the treatment of multiple diseases. Although these metalloids can both cause and cure disease, their modes of molecular action are incompletely understood. The past decades have seen major advances in our understanding of arsenic and antimony toxicity, emphasizing genotoxicity and proteotoxicity as key contributors to pathogenesis. In this review, we highlight mechanisms by which arsenic and antimony cause toxicity, focusing on their genotoxic and proteotoxic effects. The mechanisms used by cells to maintain proteostasis during metalloid exposure are also described. Furthermore, we address how metalloid-induced proteotoxicity may promote neurodegenerative disease and how genotoxicity and proteotoxicity may be interrelated and together contribute to proteinopathies. A deeper understanding of cellular toxicity and response mechanisms and their links to pathogenesis may promote the development of strategies for both disease prevention and treatment.
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Affiliation(s)
- Robert Wysocki
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328, Wroclaw, Poland.
| | - Joana I Rodrigues
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 405 30, Göteborg, Sweden
| | - Ireneusz Litwin
- Academic Excellence Hub - Research Centre for DNA Repair and Replication, Faculty of Biological Sciences, University of Wroclaw, 50-328, Wroclaw, Poland
| | - Markus J Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, 405 30, Göteborg, Sweden.
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11
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Lin G, Barnes CO, Weiss S, Dutagaci B, Qiu C, Feig M, Song J, Lyubimov A, Cohen AE, Kaplan CD, Calero G. Structural basis of transcription: RNA Polymerase II substrate binding and metal coordination at 3.0 Å using a free-electron laser. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559052. [PMID: 37790421 PMCID: PMC10543002 DOI: 10.1101/2023.09.22.559052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Catalysis and translocation of multi-subunit DNA-directed RNA polymerases underlie all cellular mRNA synthesis. RNA polymerase II (Pol II) synthesizes eukaryotic pre-mRNAs from a DNA template strand buried in its active site. Structural details of catalysis at near atomic resolution and precise arrangement of key active site components have been elusive. Here we present the free electron laser (FEL) structure of a matched ATP-bound Pol II, revealing the full active site interaction network at the highest resolution to date, including the trigger loop (TL) in the closed conformation, bonafide occupancy of both site A and B Mg2+, and a putative third (site C) Mg2+ analogous to that described for some DNA polymerases but not observed previously for cellular RNA polymerases. Molecular dynamics (MD) simulations of the structure indicate that the third Mg2+ is coordinated and stabilized at its observed position. TL residues provide half of the substrate binding pocket while multiple TL/bridge helix (BH) interactions induce conformational changes that could propel translocation upon substrate hydrolysis. Consistent with TL/BH communication, a FEL structure and MD simulations of the hyperactive Rpb1 T834P bridge helix mutant reveals rearrangement of some active site interactions supporting potential plasticity in active site function and long-distance effects on both the width of the central channel and TL conformation, likely underlying its increased elongation rate at the expense of fidelity.
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Affiliation(s)
- Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
| | - Christopher O Barnes
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena CA 91125 USA
| | - Simon Weiss
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
| | - Bercem Dutagaci
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing MI 48824 USA
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston MA 02115 USA
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing MI 48824 USA
| | - Jihnu Song
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Artem Lyubimov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh PA 15260 USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
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12
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Popescu I, Deelen J, Illario M, Adams J. Challenges in anti-aging medicine-trends in biomarker discovery and therapeutic interventions for a healthy lifespan. J Cell Mol Med 2023; 27:2643-2650. [PMID: 37610311 PMCID: PMC10494298 DOI: 10.1111/jcmm.17912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/02/2023] [Accepted: 08/07/2023] [Indexed: 08/24/2023] Open
Abstract
We are facing a growing aging population, along with increasing pressure on health systems, caused by the impact of chronic co-morbidities (i.e. cancer, cardiovascular and neurodegenerative diseases) and functional disabilities as people age. Relatively simple preventive lifestyle interventions, such as dietary restriction and physical exercise, are important contributors to active and healthy aging in the general population. However, as shown in model organisms or in 'in vitro' conditions, lifestyle-independent interventions may have additional health benefits and can even be conceived as possible reversers of the aging process. Thus, pharmaceutical laboratories, research institutes, and universities are putting more and more effort into finding new molecular pathways and druggable targets to develop gerotherapeutics. One approach is to target the driving mechanisms of aging, some of which, like cellular senescence and impaired autophagy, we discussed in an update on the biology of aging at AgingFit 2023 in Lille, France. We underline the importance of carefully and extensively testing senotherapeutics, given the pleiotropism and heterogeneity of targeted senescent cells within different organs, at different time frames. Other druggable targets emerging from new putative mechanisms, like those based on transcriptome imbalance, nucleophagy, protein phosphatase depletion, glutamine metabolism, or seno-antigenicity, have been evidenced by recent preclinical studies in classical models of aging but need to be validated in humans. Finally, we highlight several approaches in the discovery of biomarkers of healthy aging, as well as for the prediction of neurodegenerative diseases and the evaluation of rejuvenation strategies.
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Affiliation(s)
- Iuliana Popescu
- Barnstable Brown Diabetes Research CenterUniversity of Kentucky, College of MedicineLexingtonKentuckyUSA
| | - Joris Deelen
- Max Planck Institute for Biology of AgeingKölnGermany
| | - Maddalena Illario
- Department of Public Health and EDANFederico II University and HospitalNaplesItaly
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13
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Schroader JH, Handley MT, Reddy K. Inosine triphosphate pyrophosphatase: A guardian of the cellular nucleotide pool and potential mediator of RNA function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1790. [PMID: 37092460 DOI: 10.1002/wrna.1790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/10/2023] [Accepted: 03/20/2023] [Indexed: 04/25/2023]
Abstract
Inosine triphosphate pyrophosphatase (ITPase), encoded by the ITPA gene in humans, is an important enzyme that preserves the integrity of cellular nucleotide pools by hydrolyzing the noncanonical purine nucleotides (deoxy)inosine and (deoxy)xanthosine triphosphate into monophosphates and pyrophosphate. Variants in the ITPA gene can cause partial or complete ITPase deficiency. Partial ITPase deficiency is benign but clinically relevant as it is linked to altered drug responses. Complete ITPase deficiency causes a severe multisystem disorder characterized by seizures and encephalopathy that is frequently associated with fatal infantile dilated cardiomyopathy. In the absence of ITPase activity, its substrate noncanonical nucleotides have the potential to accumulate and become aberrantly incorporated into DNA and RNA. Hence, the pathophysiology of ITPase deficiency could arise from metabolic imbalance, altered DNA or RNA regulation, or from a combination of these factors. Here, we review the known functions of ITPase and highlight recent work aimed at determining the molecular basis for ITPA-associated pathogenesis which provides evidence for RNA dysfunction. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Jacob H Schroader
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
| | - Mark T Handley
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Kaalak Reddy
- The RNA Institute, University at Albany, State University of New York, Albany, New York, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, New York, USA
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14
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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: Implications for the fidelity of transcription and CRISPR/Cas9 gene editing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554670. [PMID: 37662220 PMCID: PMC10473728 DOI: 10.1101/2023.08.24.554670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G•T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R 1ρ experiments, we show that dG•rU and dT•rG mismatches in two RNA:DNA hybrids transiently form tautomeric (G enol •T/U ⇄G•T enol /U enol ) and anionic (G•T - /U - ) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG•rU - formed with a ten-fold higher propensity relative to dT - •rG and dG•dT - and this could be attributed to the lower pK a (Δ pK a ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G•T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G•U versus G•T, and indicate that anionic Watson-Crick-like G•U - could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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15
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Debès C, Papadakis A, Grönke S, Karalay Ö, Tain LS, Mizi A, Nakamura S, Hahn O, Weigelt C, Josipovic N, Zirkel A, Brusius I, Sofiadis K, Lamprousi M, Lu YX, Huang W, Esmaillie R, Kubacki T, Späth MR, Schermer B, Benzing T, Müller RU, Antebi A, Partridge L, Papantonis A, Beyer A. Ageing-associated changes in transcriptional elongation influence longevity. Nature 2023; 616:814-821. [PMID: 37046086 PMCID: PMC10132977 DOI: 10.1038/s41586-023-05922-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 03/07/2023] [Indexed: 04/14/2023]
Abstract
Physiological homeostasis becomes compromised during ageing, as a result of impairment of cellular processes, including transcription and RNA splicing1-4. However, the molecular mechanisms leading to the loss of transcriptional fidelity are so far elusive, as are ways of preventing it. Here we profiled and analysed genome-wide, ageing-related changes in transcriptional processes across different organisms: nematodes, fruitflies, mice, rats and humans. The average transcriptional elongation speed (RNA polymerase II speed) increased with age in all five species. Along with these changes in elongation speed, we observed changes in splicing, including a reduction of unspliced transcripts and the formation of more circular RNAs. Two lifespan-extending interventions, dietary restriction and lowered insulin-IGF signalling, both reversed most of these ageing-related changes. Genetic variants in RNA polymerase II that reduced its speed in worms5 and flies6 increased their lifespan. Similarly, reducing the speed of RNA polymerase II by overexpressing histone components, to counter age-associated changes in nucleosome positioning, also extended lifespan in flies and the division potential of human cells. Our findings uncover fundamental molecular mechanisms underlying animal ageing and lifespan-extending interventions, and point to possible preventive measures.
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Affiliation(s)
- Cédric Debès
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Antonios Papadakis
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | - Özlem Karalay
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Luke S Tain
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Athanasia Mizi
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Shuhei Nakamura
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Oliver Hahn
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Carina Weigelt
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Natasa Josipovic
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Anne Zirkel
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Isabell Brusius
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Konstantinos Sofiadis
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Mantha Lamprousi
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Yu-Xuan Lu
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Wenming Huang
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Reza Esmaillie
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Torsten Kubacki
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Martin R Späth
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Bernhard Schermer
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Thomas Benzing
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Roman-Ulrich Müller
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Adam Antebi
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Max Planck Institute for Biology of Ageing, Cologne, Germany.
| | - Linda Partridge
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Max Planck Institute for Biology of Ageing, Cologne, Germany.
- Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, London, UK.
| | - Argyris Papantonis
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Andreas Beyer
- Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
- Institute for Genetics, Faculty of Mathematics and Natural Sciences, University of Cologne, Cologne, Germany.
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16
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Chung C, Verheijen BM, Navapanich Z, McGann EG, Shemtov S, Lai GJ, Arora P, Towheed A, Haroon S, Holczbauer A, Chang S, Manojlovic Z, Simpson S, Thomas KW, Kaplan C, van Hasselt P, Timmers M, Erie D, Chen L, Gout JF, Vermulst M. Evolutionary conservation of the fidelity of transcription. Nat Commun 2023; 14:1547. [PMID: 36941254 PMCID: PMC10027832 DOI: 10.1038/s41467-023-36525-w] [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: 12/15/2021] [Accepted: 02/03/2023] [Indexed: 03/23/2023] Open
Abstract
Accurate transcription is required for the faithful expression of genetic information. However, relatively little is known about the molecular mechanisms that control the fidelity of transcription, or the conservation of these mechanisms across the tree of life. To address these issues, we measured the error rate of transcription in five organisms of increasing complexity and found that the error rate of RNA polymerase II ranges from 2.9 × 10-6 ± 1.9 × 10-7/bp in yeast to 4.0 × 10-6 ± 5.2 × 10-7/bp in worms, 5.69 × 10-6 ± 8.2 × 10-7/bp in flies, 4.9 × 10-6 ± 3.6 × 10-7/bp in mouse cells and 4.7 × 10-6 ± 9.9 × 10-8/bp in human cells. These error rates were modified by various factors including aging, mutagen treatment and gene modifications. For example, the deletion or modification of several related genes increased the error rate substantially in both yeast and human cells. This research highlights the evolutionary conservation of factors that control the fidelity of transcription. Additionally, these experiments provide a reasonable estimate of the error rate of transcription in human cells and identify disease alleles in a subunit of RNA polymerase II that display error-prone transcription. Finally, we provide evidence suggesting that the error rate and spectrum of transcription co-evolved with our genetic code.
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Affiliation(s)
- Claire Chung
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Bert M Verheijen
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Zoe Navapanich
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Eric G McGann
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Sarah Shemtov
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Guan-Ju Lai
- School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Payal Arora
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Atif Towheed
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Suraiya Haroon
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Agnes Holczbauer
- Children's hospital of Philadelphia, Center for Mitochondrial and Epigenomic Medicine, Philadelphia, PA, USA
| | - Sharon Chang
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Zarko Manojlovic
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Stephen Simpson
- College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH, USA
| | - Kelley W Thomas
- College of Life Sciences and Agriculture, University of New Hampshire, Durham, NH, USA
| | - Craig Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Peter van Hasselt
- Department of Metabolic Disease, University of Utrecht, Utrecht, the Netherlands
| | - Marc Timmers
- Department of Urology, Medical Center - University of Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK) Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Dorothy Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
| | - Lin Chen
- Department of Molecular and Cellular Biology, University of Southern California, Los Angeles, CA, USA
| | - Jean-Franćois Gout
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Marc Vermulst
- School of Gerontology, University of Southern California, Los Angeles, CA, USA.
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17
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The fidelity of transcription in human cells. Proc Natl Acad Sci U S A 2023; 120:e2210038120. [PMID: 36696440 PMCID: PMC9945944 DOI: 10.1073/pnas.2210038120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
To determine the error rate of transcription in human cells, we analyzed the transcriptome of H1 human embryonic stem cells with a circle-sequencing approach that allows for high-fidelity sequencing of the transcriptome. These experiments identified approximately 100,000 errors distributed over every major RNA species in human cells. Our results indicate that different RNA species display different error rates, suggesting that human cells prioritize the fidelity of some RNAs over others. Cross-referencing the errors that we detected with various genetic and epigenetic features of the human genome revealed that the in vivo error rate in human cells changes along the length of a transcript and is further modified by genetic context, repetitive elements, epigenetic markers, and the speed of transcription. Our experiments further suggest that BRCA1, a DNA repair protein implicated in breast cancer, has a previously unknown role in the suppression of transcription errors. Finally, we analyzed the distribution of transcription errors in multiple tissues of a new mouse model and found that they occur preferentially in neurons, compared to other cell types. These observations lend additional weight to the idea that transcription errors play a key role in the progression of various neurological disorders, including Alzheimer's disease.
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18
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Lim S, Liu Y, Rhie BH, Kim C, Ryu HY, Ahn SH. Sus1 maintains a normal lifespan through regulation of TREX-2 complex-mediated mRNA export. Aging (Albany NY) 2022; 14:4990-5012. [PMID: 35771153 PMCID: PMC9271307 DOI: 10.18632/aging.204146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
Eukaryotic gene expression requires multiple cellular events, including transcription and RNA processing and transport. Sus1, a common subunit in both the Spt-Ada-Gcn5 acetyltransferase (SAGA) and transcription and export complex-2 (TREX-2) complexes, is a key factor in coupling transcription activation to mRNA nuclear export. Here, we report that the SAGA DUB module and TREX-2 distinctly regulate yeast replicative lifespan in a Sir2-dependent and -independent manner, respectively. The growth and lifespan impaired by SUS1 loss depend on TREX-2 but not on the SAGA DUB module. Notably, an increased dose of the mRNA export factors Mex67 and Dbp5 rescues the growth defect, shortened lifespan, and nuclear accumulation of poly(A)+ RNA in sus1Δ cells, suggesting that boosting the mRNA export process restores the mRNA transport defect and the growth and lifespan damage in sus1Δ cells. Moreover, Sus1 is required for the proper association of Mex67 and Dbp5 with the nuclear rim. Together, these data indicate that Sus1 links transcription and mRNA nuclear export to the lifespan control pathway, suggesting that prevention of an abnormal accumulation of nuclear RNA is necessary for maintenance of a normal lifespan.
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Affiliation(s)
- Suji Lim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Yan Liu
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Byung-Ho Rhie
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Chun Kim
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
| | - Hong-Yeoul Ryu
- BK21 Plus KNU Creative BioResearch Group, School of Life Sciences, College of National Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Seong Hoon Ahn
- Department of Molecular and Life Science, College of Science and Convergence Technology, Hanyang University, Ansan, Gyeonggi-do 15588, Republic of Korea
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19
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Gene loss and compensatory evolution promotes the emergence of morphological novelties in budding yeast. Nat Ecol Evol 2022; 6:763-773. [PMID: 35484218 DOI: 10.1038/s41559-022-01730-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 03/10/2022] [Indexed: 01/05/2023]
Abstract
Deleterious mutations are generally considered to be irrelevant for morphological evolution. However, they could be compensated by conditionally beneficial mutations, thereby providing access to new adaptive paths. Here we use high-dimensional phenotyping of laboratory-evolved budding yeast lineages to demonstrate that new cellular morphologies emerge exceptionally rapidly as a by-product of gene loss and subsequent compensatory evolution. Unexpectedly, the capacities for invasive growth, multicellular aggregation and biofilm formation also spontaneously evolve in response to gene loss. These multicellular phenotypes can be achieved by diverse mutational routes and without reactivating the canonical regulatory pathways. These ecologically and clinically relevant traits originate as pleiotropic side effects of compensatory evolution and have no obvious utility in the laboratory environment. The extent of morphological diversity in the evolved lineages is comparable to that of natural yeast isolates with diverse genetic backgrounds and lifestyles. Finally, we show that both the initial gene loss and subsequent compensatory mutations contribute to new morphologies, with their synergistic effects underlying specific morphological changes. We conclude that compensatory evolution is a previously unrecognized source of morphological diversity and phenotypic novelties.
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20
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Nuclear mRNA Export and Aging. Int J Mol Sci 2022; 23:ijms23105451. [PMID: 35628261 PMCID: PMC9142925 DOI: 10.3390/ijms23105451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/10/2022] [Accepted: 05/12/2022] [Indexed: 02/04/2023] Open
Abstract
The relationship between transcription and aging is one that has been studied intensively and experimentally with diverse attempts. However, the impact of the nuclear mRNA export on the aging process following its transcription is still poorly understood, although the nuclear events after transcription are coupled closely with the transcription pathway because the essential factors required for mRNA transport, namely TREX, TREX-2, and nuclear pore complex (NPC), physically and functionally interact with various transcription factors, including the activator/repressor and pre-mRNA processing factors. Dysregulation of the mediating factors for mRNA export from the nucleus generally leads to the aberrant accumulation of nuclear mRNA and further impairment in the vegetative growth and normal lifespan and the pathogenesis of neurodegenerative diseases. The optimal stoichiometry and density of NPC are destroyed during the process of cellular aging, and their damage triggers a defect of function in the nuclear permeability barrier. This review describes recent findings regarding the role of the nuclear mRNA export in cellular aging and age-related neurodegenerative disorders.
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21
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Defective transcription elongation in human cancers imposes targetable proteotoxic vulnerability. Transl Oncol 2021; 16:101323. [PMID: 34954455 PMCID: PMC8718660 DOI: 10.1016/j.tranon.2021.101323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/12/2021] [Accepted: 12/19/2021] [Indexed: 11/24/2022] Open
Abstract
Successful cancer therapy is contingent on identifying cancer-specific aberrant phenotypes and their associated vulnerabilities. We recently reported that a subset of almost every cancer type contains a genome-wide defect in RNA Polymerase II-mediated transcription elongation (TEdef), which impairs the expression of long genes and confers resistance to anti-tumor immune attack. Using a combination of computational analysis and laboratory experiments, we report that tumor cells with TEdef have widespread overexpression of the components of the protein homeostasis machinery (mostly composed of short genes), including protein folding and clearance. Accordingly, TEdef cells were characterized by abnormally high levels of insoluble protein aggregates in the cytoplasm and autophagy influx. We present evidence that TEdef cells exhibit impaired clearance of misfolded protein aggregates through the ubiquitin-proteasome system, and thus rely on autophagy for their degradation. As such, while these cells were highly resistant to proteasome inhibitors, they were acutely sensitive to inhibitors of autophagy in vitro and in vivo. This study reveals a major aberrant phenotype that is observed in ∼15-25% of all cancers and characterizes a unique cellular vulnerability that can be readily exploited in the clinic to improve treatment efficacy.
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22
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Haste makes waste: The significance of translation fidelity for development and longevity. Mol Cell 2021; 81:3675-3676. [PMID: 34547232 DOI: 10.1016/j.molcel.2021.08.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We highlight Martinez-Miguel et al. (2021), which demonstrates that an amino acid substitution in RPS23 found in thermophilic archaea contributes to increased translation fidelity, lifespan, and stress response but slows development and reproduction in other organisms.
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23
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Verma K, Verma M, Chaphalkar A, Chakraborty K. Recent advances in understanding the role of proteostasis. Fac Rev 2021; 10:72. [PMID: 34632458 PMCID: PMC8483240 DOI: 10.12703/r/10-72] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Maintenance of a functional proteome is achieved through the mechanism of proteostasis that involves precise coordination between molecular machineries assisting a protein from its conception to demise. Although each organelle within a cell has its own set of proteostasis machinery, inter-organellar communication and cell non-autonomous signaling bring forth the multidimensional nature of the proteostasis network. Exposure to extrinsic and intrinsic stressors can challenge the proteostasis network, leading to the accumulation of aberrant proteins or a decline in the proteostasis components, as seen during aging and in several diseases. Here, we summarize recent advances in understanding the role of proteostasis and its regulation in aging and disease, including monogenetic and infectious diseases. We highlight some of the emerging as well as unresolved questions in proteostasis that need to be addressed to overcome pathologies associated with damaged proteins and to promote healthy aging.
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Affiliation(s)
- Kanika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Monika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Aseem Chaphalkar
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Kausik Chakraborty
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
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24
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Andersson S, Romero A, Rodrigues JI, Hua S, Hao X, Jacobson T, Karl V, Becker N, Ashouri A, Rauch S, Nyström T, Liu B, Tamás MJ. Genome-wide imaging screen uncovers molecular determinants of arsenite-induced protein aggregation and toxicity. J Cell Sci 2021; 134:jcs258338. [PMID: 34085697 PMCID: PMC8214759 DOI: 10.1242/jcs.258338] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/03/2021] [Indexed: 12/20/2022] Open
Abstract
The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis. This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Stefanie Andersson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Antonia Romero
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Joana Isabel Rodrigues
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Sansan Hua
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Xinxin Hao
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
- Institute of Biomedicine - Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Göteborg, Sweden
| | - Therese Jacobson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Vivien Karl
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Nathalie Becker
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Arghavan Ashouri
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Sebastien Rauch
- Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Thomas Nyström
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
- Institute of Biomedicine - Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Göteborg, Sweden
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Markus J. Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
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25
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Fritsch C, Gout JF, Haroon S, Towheed A, Chung C, LaGosh J, McGann E, Zhang X, Song Y, Simpson S, Danthi PS, Benayoun BA, Wallace D, Thomas K, Lynch M, Vermulst M. Genome-wide surveillance of transcription errors in response to genotoxic stress. Proc Natl Acad Sci U S A 2021; 118:e2004077118. [PMID: 33443141 PMCID: PMC7817157 DOI: 10.1073/pnas.2004077118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutagenic compounds are a potent source of human disease. By inducing genetic instability, they can accelerate the evolution of human cancers or lead to the development of genetically inherited diseases. Here, we show that in addition to genetic mutations, mutagens are also a powerful source of transcription errors. These errors arise in dividing and nondividing cells alike, affect every class of transcripts inside cells, and, in certain cases, greatly exceed the number of mutations that arise in the genome. In addition, we reveal the kinetics of transcription errors in response to mutagen exposure and find that DNA repair is required to mitigate transcriptional mutagenesis after exposure. Together, these observations have far-reaching consequences for our understanding of mutagenesis in human aging and disease, and suggest that the impact of DNA damage on human physiology has been greatly underestimated.
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Affiliation(s)
- C Fritsch
- Department of Cellular and Molecular Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - J-F Gout
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762
| | - S Haroon
- Department of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - A Towheed
- Touro College of Osteopathic Medicine, Middletown, NY 10940
| | - C Chung
- School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - J LaGosh
- School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - E McGann
- School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - X Zhang
- Bioinforx, Inc., Madison, WI 53719
| | - Y Song
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, University of Pennsylvania, Philadelphia, PA 19104
| | - S Simpson
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824
| | - P S Danthi
- School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - B A Benayoun
- School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - D Wallace
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, University of Pennsylvania, Philadelphia, PA 19104
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104
| | - K Thomas
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824
| | - M Lynch
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85287;
| | - M Vermulst
- School of Gerontology, University of Southern California, Los Angeles, CA 90089;
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104
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26
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Anagnostou M, Chung C, McGann E, Verheijen B, Kou Y, Chen L, Vermulst M. Transcription errors in aging and disease. TRANSLATIONAL MEDICINE OF AGING 2021. [DOI: 10.1016/j.tma.2021.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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27
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Proteotoxic Stress and Cell Death in Cancer Cells. Cancers (Basel) 2020; 12:cancers12092385. [PMID: 32842524 PMCID: PMC7563887 DOI: 10.3390/cancers12092385] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
To maintain proteostasis, cells must integrate information and activities that supervise protein synthesis, protein folding, conformational stability, and also protein degradation. Extrinsic and intrinsic conditions can both impact normal proteostasis, causing the appearance of proteotoxic stress. Initially, proteotoxic stress elicits adaptive responses aimed at restoring proteostasis, allowing cells to survive the stress condition. However, if the proteostasis restoration fails, a permanent and sustained proteotoxic stress can be deleterious, and cell death ensues. Many cancer cells convive with high levels of proteotoxic stress, and this condition could be exploited from a therapeutic perspective. Understanding the cell death pathways engaged by proteotoxic stress is instrumental to better hijack the proliferative fate of cancer cells.
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28
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Rangarajan N, Kapoor I, Li S, Drossopoulos P, White KK, Madden VJ, Dohlman HG. Potassium starvation induces autophagy in yeast. J Biol Chem 2020; 295:14189-14202. [PMID: 32788210 DOI: 10.1074/jbc.ra120.014687] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/02/2020] [Indexed: 01/04/2023] Open
Abstract
Autophagy is a conserved process that recycles cellular contents to promote survival. Although nitrogen limitation is the canonical inducer of autophagy, recent studies have revealed several other nutrients important to this process. In this study, we used a quantitative, high-throughput assay to identify potassium starvation as a new and potent inducer of autophagy in the yeast Saccharomyces cerevisiae We found that potassium-dependent autophagy requires the core pathway kinases Atg1, Atg5, and Vps34, and other components of the phosphatidylinositol 3-kinase complex. Transmission EM revealed abundant autophagosome formation in response to both stimuli. RNA-Seq indicated distinct transcriptional responses: nitrogen affects transport of ions such as copper, whereas potassium targets the organization of other cellular components. Thus, nitrogen and potassium share the ability to influence molecular supply and demand but do so in different ways. Both inputs promote catabolism through bulk autophagy, but result in distinct mechanisms of cellular remodeling and synthesis.
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Affiliation(s)
- Nambirajan Rangarajan
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ishani Kapoor
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Shuang Li
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter Drossopoulos
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Kristen K White
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Victoria J Madden
- Microscopy Services Laboratory, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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29
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Cheung PPH, Jiang B, Booth GT, Chong TH, Unarta IC, Wang Y, Suarez GD, Wang J, Lis JT, Huang X. Identifying Transcription Error-Enriched Genomic Loci Using Nuclear Run-on Circular-Sequencing Coupled with Background Error Modeling. J Mol Biol 2020; 432:3933-3949. [PMID: 32325070 DOI: 10.1016/j.jmb.2020.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 01/30/2023]
Abstract
RNA polymerase transcribes certain genomic loci with higher errors rates. These transcription error-enriched genomic loci (TEELs) have implications in disease. Current deep-sequencing methods cannot distinguish TEELs from post-transcriptional modifications, stochastic transcription errors, and technical noise, impeding efforts to elucidate the mechanisms linking TEELs to disease. Here, we describe background error model-coupled precision nuclear run-on circular-sequencing (EmPC-seq) to discern genomic regions enriched for transcription misincorporations. EmPC-seq innovatively combines a nuclear run-on assay for capturing nascent RNA before post-transcriptional modifications, a circular-sequencing step that sequences the same nascent RNA molecules multiple times to improve accuracy, and a statistical model for distinguishing error-enriched regions among stochastic polymerase errors. Applying EmPC-seq to the ribosomal RNA transcriptome, we show that TEELs of RNA polymerase I are not randomly distributed but clustered together, with higher error frequencies at nascent transcript 3' ends. Our study establishes a reliable method of identifying TEELs with nucleotide precision, which can help elucidate their molecular origins.
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Affiliation(s)
- Peter Pak-Hang Cheung
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China; Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Biaobin Jiang
- Division of Life Science, Department of Chemical and Biological Engineering, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong; The HKUST Jockey Club Institute for Advanced Study (IAS), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Gregory T Booth
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Tin Hang Chong
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China
| | - Ilona Christy Unarta
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Yuqing Wang
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Gianmarco D Suarez
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Jiguang Wang
- Division of Life Science, Department of Chemical and Biological Engineering, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA; The HKUST Jockey Club Institute for Advanced Study (IAS), The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
| | - Xuhui Huang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China; Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong; Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.
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30
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Li W, Lynch M. Universally high transcript error rates in bacteria. eLife 2020; 9:54898. [PMID: 32469307 PMCID: PMC7259958 DOI: 10.7554/elife.54898] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/28/2020] [Indexed: 12/22/2022] Open
Abstract
Errors can occur at any level during the replication and transcription of genetic information. Genetic mutations derived mainly from replication errors have been extensively studied. However, fundamental details of transcript errors, such as their rate, molecular spectrum, and functional effects, remain largely unknown. To globally identify transcript errors, we applied an adapted rolling-circle sequencing approach to Escherichia coli, Bacillus subtilis, Agrobacterium tumefaciens, and Mesoplasma florum, revealing transcript-error rates 3 to 4 orders of magnitude higher than the corresponding genetic mutation rates. The majority of detected errors would result in amino-acid changes, if translated. With errors identified from 9929 loci, the molecular spectrum and distribution of errors were uncovered in great detail. A G→A substitution bias was observed in M. florum, which apparently has an error-prone RNA polymerase. Surprisingly, an increased frequency of nonsense errors towards the 3' end of mRNAs was observed, suggesting a Nonsense-Mediated Decay-like quality-control mechanism in prokaryotes.
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Affiliation(s)
- Weiyi Li
- Department of Biology, Indiana University, Bloomington, United States
| | - Michael Lynch
- Department of Biology, Indiana University, Bloomington, United States.,Center for Mechanisms of Evolution, The Biodesign Institute, Arizona State University, Tempe, United States
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31
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Ghosh A, Williams LD, Pestov DG, Shcherbik N. Proteotoxic stress promotes entrapment of ribosomes and misfolded proteins in a shared cytosolic compartment. Nucleic Acids Res 2020; 48:3888-3905. [PMID: 32030400 PMCID: PMC7144922 DOI: 10.1093/nar/gkaa068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/03/2020] [Accepted: 01/21/2020] [Indexed: 11/23/2022] Open
Abstract
Cells continuously monitor protein synthesis to prevent accumulation of aberrant polypeptides. Insufficient capacity of cellular degradative systems, chaperone shortage or high levels of mistranslation by ribosomes can result in proteotoxic stress and endanger proteostasis. One of the least explored reasons for mistranslation is the incorrect functioning of the ribosome itself. To understand how cells deal with ribosome malfunction, we introduced mutations in the Expansion Segment 7 (ES7L) of 25S rRNA that allowed the formation of mature, translationally active ribosomes but induced proteotoxic stress and compromised cell viability. The ES7L-mutated ribosomes escaped nonfunctional rRNA Decay (NRD) and remained stable. Remarkably, ES7L-mutated ribosomes showed increased segregation into cytoplasmic foci containing soluble misfolded proteins. This ribosome entrapment pathway, termed TRAP (Translational Relocalization with Aberrant Polypeptides), was generalizable beyond the ES7L mutation, as wild-type ribosomes also showed increased relocalization into the same compartments in cells exposed to proteotoxic stressors. We propose that during TRAP, assembled ribosomes associated with misfolded nascent chains move into cytoplasmic compartments enriched in factors that facilitate protein quality control. In addition, TRAP may help to keep translation at its peak efficiency by preventing malfunctioning ribosomes from active duty in translation.
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Affiliation(s)
- Arnab Ghosh
- Department for Cell Biology and Neuroscience, Rowan University, School of Osteopathic Medicine, 2 Medical Center Drive, Stratford, NJ 08084, USA
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, 315 Ferst Drive NW, Atlanta, GA 30332, USA
| | - Dimitri G Pestov
- Department for Cell Biology and Neuroscience, Rowan University, School of Osteopathic Medicine, 2 Medical Center Drive, Stratford, NJ 08084, USA
| | - Natalia Shcherbik
- Department for Cell Biology and Neuroscience, Rowan University, School of Osteopathic Medicine, 2 Medical Center Drive, Stratford, NJ 08084, USA
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32
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Ren J, Liu Y, Wang S, Wang Y, Li W, Chen S, Cui D, Yang S, Li MY, Feng B, Lai PBS, Chen GG. The FKH domain in FOXP3 mRNA frequently contains mutations in hepatocellular carcinoma that influence the subcellular localization and functions of FOXP3. J Biol Chem 2020; 295:5484-5495. [PMID: 32198183 PMCID: PMC7170510 DOI: 10.1074/jbc.ra120.012518] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/12/2020] [Indexed: 01/16/2023] Open
Abstract
The transcription factor forkhead box P3 (FOXP3) is a biomarker for regulatory T cells and can also be expressed in cancer cells, but its function in cancer appears to be divergent. The role of hepatocyte-expressed FOXP3 in hepatocellular carcinoma (HCC) is unknown. Here, we collected tumor samples and clinical information from 115 HCC patients and used five human cancer cell lines. We examined FOXP3 mRNA sequences for mutations, used a luciferase assay to assess promoter activities of FOXP3's target genes, and employed mouse tumor models to confirm in vitro results. We detected mutations in the FKH domain of FOXP3 mRNAs in 33% of the HCC tumor tissues, but in none of the adjacent nontumor tissues. None of the mutations occurred at high frequency, indicating that they occurred randomly. Notably, the mutations were not detected in the corresponding regions of FOXP3 genomic DNA, and many of them resulted in amino acid substitutions in the FKH region, altering FOXP3's subcellular localization. FOXP3 delocalization from the nucleus to the cytoplasm caused loss of transcriptional regulation of its target genes, inactivated its tumor-inhibitory capability, and changed cellular responses to histone deacetylase (HDAC) inhibitors. More complex FKH mutations appeared to be associated with worse prognosis in HCC patients. We conclude that mutations in the FKH domain of FOXP3 mRNA frequently occur in HCC and that these mutations are caused by errors in transcription and are not derived from genomic DNA mutations. Our results suggest that transcriptional mutagenesis of FOXP3 plays a role in HCC.
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Affiliation(s)
- Jianwei Ren
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute (SZRI), Chinese University of Hong Kong, Shenzhen 518057, China
| | - Yi Liu
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, Guangdong 524023, China
| | - Shanshan Wang
- School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Yu Wang
- Division of Cellular & Molecular Research, National Cancer Centre, Singapore 169610
| | - Wende Li
- Guangdong Laboratory Animals Monitoring Institute, Guangzhou 510663, China
| | - Siyu Chen
- Guangdong Laboratory Animals Monitoring Institute, Guangzhou 510663, China
| | - Dexuan Cui
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Shengli Yang
- Union Hospital Tumour Center, Wuhan 430022, China
| | - Ming-Yue Li
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510320, China
| | - Bo Feng
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Paul B S Lai
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China.
| | - George G Chen
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China; Shenzhen Research Institute (SZRI), Chinese University of Hong Kong, Shenzhen 518057, China; Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, Guangdong 524023, China; Department of Otorhinolaryngology, Head and Neck Surgery, Chinese University of Hong Kong, Hong Kong, China.
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33
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Immunohistochemical detection of the pro-apoptotic Bax∆2 protein in human tissues. Histochem Cell Biol 2020; 154:41-53. [PMID: 32200452 DOI: 10.1007/s00418-020-01874-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2020] [Indexed: 12/11/2022]
Abstract
The pro-apoptotic Bax isoform Bax∆2 was originally discovered in cancer patients with a microsatellite guanine deletion (G8 to G7). This deletion leads to an early stop codon; however, when combined with the alternative splicing of exon 2, the reading frame is restored allowing production of a full-length protein (Bax∆2). Unlike the parental Baxα, Bax∆2 triggers apoptosis through a non-mitochondrial pathway and the expression in human tissues was unknown. Here, we analyzed over 1000 tissue microarray samples from 13 different organs using immunohistochemistry. Bax∆2-positive cells were detected in all examined organs at low rates (1-5%) and mainly scattered throughout the connective tissues. Surprisingly, over 70% of normal colon samples scored high for BaxΔ2-positive staining. Only 7% of malignant colon samples scored high, with most high-grade tumors being negative. A similar pattern was observed in most organs examined. We also showed that both Baxα and Bax∆2 can co-exist in the same cells. Genotyping showed that the majority of Bax∆2-positive normal tissues contain no G7 mutation, but an unexpected high rate of G9 was observed. Although the underlying mechanism remains to be explored, the inverse correlation of Bax∆2 expression with tissue malignancy suggests that it may have a clinical implication in cancer development and treatment.
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34
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Srivastava S. Emerging Insights into the Metabolic Alterations in Aging Using Metabolomics. Metabolites 2019; 9:E301. [PMID: 31847272 PMCID: PMC6950098 DOI: 10.3390/metabo9120301] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/08/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
Metabolomics is the latest 'omics' technology and systems biology science that allows for comprehensive profiling of small-molecule metabolites in biological systems at a specific time and condition. Metabolites are cellular intermediate products of metabolic reactions, which reflect the ultimate response to genomic, transcriptomic, proteomic, or environmental changes in a biological system. Aging is a complex biological process that is characterized by a gradual and progressive decline in molecular, cellular, tissue, organ, and organismal functions, and it is influenced by a combination of genetic, environmental, diet, and lifestyle factors. The precise biological mechanisms of aging remain unknown. Metabolomics has emerged as a powerful tool to characterize the organism phenotypes, identify altered metabolites, pathways, novel biomarkers in aging and disease, and offers wide clinical applications. Here, I will provide a comprehensive overview of our current knowledge on metabolomics led studies in aging with particular emphasis on studies leading to biomarker discovery. Based on the data obtained from model organisms and humans, it is evident that metabolites associated with amino acids, lipids, carbohydrate, and redox metabolism may serve as biomarkers of aging and/or longevity. Current challenges and key questions that should be addressed in the future to advance our understanding of the biological mechanisms of aging are discussed.
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Affiliation(s)
- Sarika Srivastava
- Fralin Biomedical Research Institute at Virginia Tech Carilion, 2 Riverside Circle, Roanoke, VA 24016, USA
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35
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Transcriptional Fidelity of Mitochondrial RNA Polymerase RpoTm from Arabidopsis thaliana. J Mol Biol 2019; 431:4767-4783. [PMID: 31626802 DOI: 10.1016/j.jmb.2019.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 05/30/2019] [Accepted: 08/26/2019] [Indexed: 11/21/2022]
Abstract
Fidelity of RNA synthesis is essential for the faithful transfer of information from DNA to RNA. A comprehensive analysis of the nucleotide selectivity by the mitochondrial RNA polymerase (RNAP) RpoTm, from Arabidopsis thaliana, has been carried out. The kinetic parameters for the incorporation of cognate, noncognate, and oxidized bases have been determined. The results establish high fidelity of mitochondrial transcription resembling those of replicative polymerases in the absence of repair. In addition, RpoTm incorporates oxidized nucleotides with similar efficiency compared with mismatches and is capable of extending the RNA beyond the insertion of the oxidized base. Furthermore, lesion bypass study on RpoTm demonstrates that the enzyme bypasses 8-oxo-guanine by insertion of adenine leading to C to A mutations in RNA. Homology modeling of RpoTm elongation complex allows delineation of the residues necessary for stabilizing the incoming NTP substrate and for posing the template nucleotide residue. Substitution of these residues leads to compromise in the activity of the enzyme corroborating their importance in RNA synthesis. Comparison of the data with T7 RNAPs indicates that low efficiency of misincorporation is a universal strategy used by single-subunit RNAPs for maintaining high fidelity in the absence of proofreading and repair activity in mitochondria.
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36
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Bradley CC, Gordon AJE, Halliday JA, Herman C. Transcription fidelity: New paradigms in epigenetic inheritance, genome instability and disease. DNA Repair (Amst) 2019; 81:102652. [PMID: 31326363 DOI: 10.1016/j.dnarep.2019.102652] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA transcription errors are transient, yet frequent, events that do have consequences for the cell. However, until recently we lacked the tools to empirically measure and study these errors. Advances in RNA library preparation and next generation sequencing (NGS) have allowed the spectrum of transcription errors to be empirically measured over the entire transcriptome and in nascent transcripts. Combining these powerful methods with forward and reverse genetic strategies has refined our understanding of transcription factors known to enhance RNA accuracy and will enable the discovery of new candidates. Furthermore, these approaches will shed additional light on the complex interplay between transcription fidelity and other DNA transactions, such as replication and repair, and explore a role for transcription errors in cellular evolution and disease.
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Affiliation(s)
- Catherine C Bradley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, 77030, USA; Robert and Janice McNair Foundation/ McNair Medical Institute M.D./Ph.D. Scholars Program, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, 77030, USA.
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37
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Huang C, Wagner-Valladolid S, Stephens AD, Jung R, Poudel C, Sinnige T, Lechler MC, Schlörit N, Lu M, Laine RF, Michel CH, Vendruscolo M, Kaminski CF, Kaminski Schierle GS, David DC. Intrinsically aggregation-prone proteins form amyloid-like aggregates and contribute to tissue aging in Caenorhabditis elegans. eLife 2019; 8:e43059. [PMID: 31050339 PMCID: PMC6524967 DOI: 10.7554/elife.43059] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 05/02/2019] [Indexed: 12/13/2022] Open
Abstract
Reduced protein homeostasis leading to increased protein instability is a common molecular feature of aging, but it remains unclear whether this is a cause or consequence of the aging process. In neurodegenerative diseases and other amyloidoses, specific proteins self-assemble into amyloid fibrils and accumulate as pathological aggregates in different tissues. More recently, widespread protein aggregation has been described during normal aging. Until now, an extensive characterization of the nature of age-dependent protein aggregation has been lacking. Here, we show that age-dependent aggregates are rapidly formed by newly synthesized proteins and have an amyloid-like structure resembling that of protein aggregates observed in disease. We then demonstrate that age-dependent protein aggregation accelerates the functional decline of different tissues in C. elegans. Together, these findings imply that amyloid-like aggregates contribute to the aging process and therefore could be important targets for strategies designed to maintain physiological functions in the late stages of life.
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Affiliation(s)
- Chaolie Huang
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
| | - Sara Wagner-Valladolid
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Amberley D Stephens
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Raimund Jung
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
| | - Chetan Poudel
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Tessa Sinnige
- Department of ChemistryUniversity of CambridgeCambridgeUnited Kingdom
| | - Marie C Lechler
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
- Graduate Training Centre of NeuroscienceUniversity of TübingenTübingenGermany
| | - Nicole Schlörit
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
- Graduate Training Centre of NeuroscienceUniversity of TübingenTübingenGermany
| | - Meng Lu
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Romain F Laine
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Claire H Michel
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | | | - Clemens F Kaminski
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUnited Kingdom
| | | | - Della C David
- German Center for Neurodegenerative Diseases (DZNE)TübingenGermany
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38
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Ka Man Tse C, Xu J, Xu L, Sheong FK, Wang S, Chow HY, Gao X, Li X, Cheung PPH, Wang D, Zhang Y, Huang X. Intrinsic Cleavage of RNA Polymerase II Adopts a Nucleobase-independent Mechanism Assisted by Transcript Phosphate. Nat Catal 2019; 2:228-235. [PMID: 31179024 PMCID: PMC6548511 DOI: 10.1038/s41929-019-0227-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
Abstract
RNA polymerase II (Pol II) utilises the same active site for polymerization and intrinsic cleavage. Pol II proofreads the nascent transcript by its intrinsic nuclease activity to maintain high transcriptional fidelity critical for cell growth and viability. The detailed catalytic mechanism of intrinsic cleavage remains unknown. Here, we combined ab initio quantum mechanics/molecular mechanics studies and biochemical cleavage assays to show that Pol II utilises downstream phosphate oxygen to activate the attacking nucleophile in hydrolysis, while the newly formed 3'-end is protonated through active-site water without a defined general acid. Experimentally, alteration of downstream phosphate oxygen either by 2'-5' sugar linkage or stereo-specific thio-substitution of phosphate oxygen drastically reduced cleavage rate. We showed by N7-modification that guanine nucleobase does not directly involve as acid-base catalyst. Our proposed mechanism provides important insights into the understanding of intrinsic transcriptional cleavage reaction, an essential step of transcriptional fidelity control.
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Affiliation(s)
- Carmen Ka Man Tse
- Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Jun Xu
- Department of Cellular and Molecular Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Liang Xu
- Department of Cellular and Molecular Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry, Sun Yat-Sen University, Guangzhou, China
| | - Fu Kit Sheong
- Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Shenglong Wang
- Department of Chemistry, New York University, New York, New York 10003 United States
| | - Hoi Yee Chow
- Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong, Hong Kong
| | - Xin Gao
- Computational Bioscience Research Centre (CBRC), CEMSE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Xuechen Li
- Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong, Hong Kong
| | - Peter Pak-Hang Cheung
- Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Dong Wang
- Department of Cellular and Molecular Medicine, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, New York 10003 United States
- NYU-ECNU Centre for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
| | - Xuhui Huang
- Department of Chemistry, Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
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Wong HE, Huang CJ, Zhang Z. Amino Acid Misincorporation Propensities Revealed through Systematic Amino Acid Starvation. Biochemistry 2018; 57:6767-6779. [DOI: 10.1021/acs.biochem.8b00976] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- H. Edward Wong
- Process Development, Amgen, Inc., 1 Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Chung-Jr Huang
- Process Development, Amgen, Inc., 1 Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Zhongqi Zhang
- Process Development, Amgen, Inc., 1 Amgen Center Drive, Thousand Oaks, California 91320, United States
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40
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Sivaramakrishnan P, Gordon AJE, Halliday JA, Herman C. How Acts of Infidelity Promote DNA Break Repair: Collision and Collusion Between DNA Repair and Transcription. Bioessays 2018; 40:e1800045. [PMID: 30091472 PMCID: PMC6334755 DOI: 10.1002/bies.201800045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/07/2018] [Indexed: 12/20/2022]
Abstract
Transcription is a fundamental cellular process and the first step in gene regulation. Although RNA polymerase (RNAP) is highly processive, in growing cells the progression of transcription can be hindered by obstacles on the DNA template, such as damaged DNA. The authors recent findings highlight a trade-off between transcription fidelity and DNA break repair. While a lot of work has focused on the interaction between transcription and nucleotide excision repair, less is known about how transcription influences the repair of DNA breaks. The authors suggest that when the cell experiences stress from DNA breaks, the control of RNAP processivity affects the balance between preserving transcription integrity and DNA repair. Here, how the conflict between transcription and DNA double-strand break (DSB) repair threatens the integrity of both RNA and DNA are discussed. In reviewing this field, the authors speculate on cellular paradigms where this equilibrium is well sustained, and instances where the maintenance of transcription fidelity is favored over genome stability.
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Affiliation(s)
- Priya Sivaramakrishnan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Baylor College of Medicine, Dan L. Duncan Comprehensive Cancer Center, Houston, TX 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA
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Abstract
SIGNIFICANCE Aging is a complex trait that is influenced by a combination of genetic and environmental factors. Although many cellular and physiological changes have been described to occur with aging, the precise molecular causes of aging remain unknown. Given the biological complexity and heterogeneity of the aging process, understanding the mechanisms that underlie aging requires integration of data about age-dependent changes that occur at the molecular, cellular, tissue, and organismal levels. Recent Advances: The development of high-throughput technologies such as next-generation sequencing, proteomics, metabolomics, and automated imaging techniques provides researchers with new opportunities to understand the mechanisms of aging. Using these methods, millions of biological molecules can be simultaneously monitored during the aging process with high accuracy and specificity. CRITICAL ISSUES Although the ability to produce big data has drastically increased over the years, integration and interpreting of high-throughput data to infer regulatory relationships between biological factors and identify causes of aging remain the major challenges. In this review, we describe recent advances and survey emerging omics approaches in aging research. We then discuss their limitations and emphasize the need for the further development of methods for the integration of different types of data. FUTURE DIRECTIONS Combining omics approaches and novel methods for single-cell analysis with systems biology tools would allow building interaction networks and investigate how these networks are perturbed with aging and disease states. Together, these studies are expected to provide a better understanding of the aging process and could provide insights into the pathophysiology of many age-associated human diseases. Antioxid. Redox Signal. 29, 985-1002.
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Affiliation(s)
- Jared S Lorusso
- 1 Department of Dermatology, Boston University School of Medicine , Boston, Massachusetts
| | - Oleg A Sviderskiy
- 2 Department of Ecology and Life Safety, Samara National Research University , Samara, Russia
| | - Vyacheslav M Labunskyy
- 1 Department of Dermatology, Boston University School of Medicine , Boston, Massachusetts
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42
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Fritsch C, Gout JFP, Vermulst M. Genome-wide Surveillance of Transcription Errors in Eukaryotic Organisms. J Vis Exp 2018. [PMID: 30272673 DOI: 10.3791/57731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Accurate transcription is required for the faithful expression of genetic information. Surprisingly though, little is known about the mechanisms that control the fidelity of transcription. To fill this gap in scientific knowledge, we recently optimized the circle-sequencing assay to detect transcription errors throughout the transcriptome of Saccharomyces cerevisiae, Drosophila melanogaster, and Caenorhabditis elegans. This protocol will provide researchers with a powerful new tool to map the landscape of transcription errors in eukaryotic cells so that the mechanisms that control the fidelity of transcription can be elucidated in unprecedented detail.
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Affiliation(s)
- Clark Fritsch
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia; Department of Cellular and Molecular Biology, University of Pennsylvania
| | - Jean-Francois Pierre Gout
- Department of Biological Sciences, Mississippi State University; Center for Mechanisms of Evolution, Biodesign Institute, Arizona State University
| | - Marc Vermulst
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia;
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43
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Verheijen BM, Vermulst M, van Leeuwen FW. Somatic mutations in neurons during aging and neurodegeneration. Acta Neuropathol 2018; 135:811-826. [PMID: 29705908 PMCID: PMC5954077 DOI: 10.1007/s00401-018-1850-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 12/22/2022]
Abstract
The nervous system is composed of a large variety of neurons with a diverse array of morphological and functional properties. This heterogeneity is essential for the construction and maintenance of a distinct set of neural networks with unique characteristics. Accumulating evidence now indicates that neurons do not only differ at a functional level, but also at the genomic level. These genomic discrepancies seem to be the result of somatic mutations that emerge in nervous tissue during development and aging. Ultimately, these mutations bring about a genetically heterogeneous population of neurons, a phenomenon that is commonly referred to as "somatic brain mosaicism". Improved understanding of the development and consequences of somatic brain mosaicism is crucial to understand the impact of somatic mutations on neuronal function in human aging and disease. Here, we highlight a number of topics related to somatic brain mosaicism, including some early experimental evidence for somatic mutations in post-mitotic neurons of the hypothalamo-neurohypophyseal system. We propose that age-related somatic mutations are particularly interesting, because aging is a major risk factor for a variety of neuronal diseases, including Alzheimer's disease. We highlight potential links between somatic mutations and the development of these diseases and argue that recent advances in single-cell genomics and in vivo physiology have now finally made it possible to dissect the origins and consequences of neuronal mutations in unprecedented detail.
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Affiliation(s)
- Bert M Verheijen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG, Utrecht, The Netherlands.
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3508 GA, Utrecht, The Netherlands.
| | - Marc Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Fred W van Leeuwen
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, 6229 ER, Maastricht, The Netherlands
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44
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O6-methylguanine-induced transcriptional mutagenesis reduces p53 tumor-suppressor function. Proc Natl Acad Sci U S A 2018; 115:4731-4736. [PMID: 29666243 PMCID: PMC5939098 DOI: 10.1073/pnas.1721764115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The impact of DNA lesions on replication and mutagenesis is of high relevance for human health; however, the role of lesion-induced transcriptional mutagenesis (TM) in disease development is unknown. Here, the impact of O6-methylguanine–induced TM on p53 function as a tumor suppressor was investigated in human cells. Results showed that TM in 15% of the transcripts resulted in a reduced ability of p53 protein to transactivate genes that regulate cell-cycle arrest and induction of apoptosis. This resulted in the loss of functional cell-cycle checkpoints and in impaired activation of apoptosis, both canonical p53 tumor-suppressor functions. This work provides evidence that TM can induce phenotypic changes in mammalian cells that have important implications for its role in tumorigenesis. Altered protein function due to mutagenesis plays an important role in disease development. This is perhaps most evident in tumorigenesis and the associated loss or gain of function of tumor-suppressor genes and oncogenes. The extent to which lesion-induced transcriptional mutagenesis (TM) influences protein function and its contribution to the development of disease is not well understood. In this study, the impact of O6-methylguanine on the transcription fidelity of p53 and the subsequent effects on the protein’s function as a regulator of cell death and cell-cycle arrest were examined in human cells. Levels of TM were determined by RNA-sequencing. In cells with active DNA repair, misincorporation of uridine opposite the lesion occurred in 0.14% of the transcripts and increased to 14.7% when repair by alkylguanine–DNA alkyltransferase was compromised. Expression of the dominant-negative p53 R248W mutant due to TM significantly reduced the transactivation of several established p53 target genes that mediate the tumor-suppressor function, including CDKN1A (p21) and BBC3 (PUMA). This resulted in deregulated signaling through the retinoblastoma protein and loss of G1/S cell-cycle checkpoint function. In addition, we observed impaired activation of apoptosis coupled to the reduction of the tumor-suppressor functions of p53. Taking these findings together, this work provides evidence that TM can induce phenotypic changes in mammalian cells that have important implications for the role of TM in tumorigenesis.
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45
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Sein H, Reinmets K, Peil K, Kristjuhan K, Värv S, Kristjuhan A. Rpb9-deficient cells are defective in DNA damage response and require histone H3 acetylation for survival. Sci Rep 2018; 8:2949. [PMID: 29440683 PMCID: PMC5811553 DOI: 10.1038/s41598-018-21110-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/29/2018] [Indexed: 11/09/2022] Open
Abstract
Rpb9 is a non-essential subunit of RNA polymerase II that is involved in DNA transcription and repair. In budding yeast, deletion of RPB9 causes several phenotypes such as slow growth and temperature sensitivity. We found that simultaneous mutation of multiple N-terminal lysines within histone H3 was lethal in rpb9Δ cells. Our results indicate that hypoacetylation of H3 leads to inefficient repair of DNA double-strand breaks, while activation of the DNA damage checkpoint regulators γH2A and Rad53 is suppressed in Rpb9-deficient cells. Combination of H3 hypoacetylation with the loss of Rpb9 leads to genomic instability, aberrant segregation of chromosomes in mitosis, and eventually to cell death. These results indicate that H3 acetylation becomes essential for efficient DNA repair and cell survival if a DNA damage checkpoint is defective.
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Affiliation(s)
- Henel Sein
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kristina Reinmets
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kadri Peil
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Kersti Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia
| | - Signe Värv
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia.,Department of Biosciences, Section for Biochemistry and Molecular Biology, University of Oslo, Blindernveien 31, 0371, Oslo, Norway
| | - Arnold Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010, Tartu, Estonia.
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46
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Verheijen BM, van Leeuwen FW. Commentary: The landscape of transcription errors in eukaryotic cells. Front Genet 2017; 8:219. [PMID: 29313848 PMCID: PMC5735076 DOI: 10.3389/fgene.2017.00219] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/05/2017] [Indexed: 12/18/2022] Open
Affiliation(s)
- Bert M Verheijen
- Laboratory of Experimental Neurology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Fred W van Leeuwen
- Department of Neuroscience, Maastricht University, Maastricht, Netherlands
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47
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von der Haar T, Leadsham JE, Sauvadet A, Tarrant D, Adam IS, Saromi K, Laun P, Rinnerthaler M, Breitenbach-Koller H, Breitenbach M, Tuite MF, Gourlay CW. The control of translational accuracy is a determinant of healthy ageing in yeast. Open Biol 2017; 7:rsob.160291. [PMID: 28100667 PMCID: PMC5303280 DOI: 10.1098/rsob.160291] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 12/08/2016] [Indexed: 12/18/2022] Open
Abstract
Life requires the maintenance of molecular function in the face of stochastic processes that tend to adversely affect macromolecular integrity. This is particularly relevant during ageing, as many cellular functions decline with age, including growth, mitochondrial function and energy metabolism. Protein synthesis must deliver functional proteins at all times, implying that the effects of protein synthesis errors like amino acid misincorporation and stop-codon read-through must be minimized during ageing. Here we show that loss of translational accuracy accelerates the loss of viability in stationary phase yeast. Since reduced translational accuracy also reduces the folding competence of at least some proteins, we hypothesize that negative interactions between translational errors and age-related protein damage together overwhelm the cellular chaperone network. We further show that multiple cellular signalling networks control basal error rates in yeast cells, including a ROS signal controlled by mitochondrial activity, and the Ras pathway. Together, our findings indicate that signalling pathways regulating growth, protein homeostasis and energy metabolism may jointly safeguard accurate protein synthesis during healthy ageing.
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Affiliation(s)
- Tobias von der Haar
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Jane E Leadsham
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Aimie Sauvadet
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Daniel Tarrant
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Ilectra S Adam
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Kofo Saromi
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Peter Laun
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | | | - Michael Breitenbach
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | - Mick F Tuite
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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48
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Paredes JA, Ezerskyte M, Bottai M, Dreij K. Transcriptional mutagenesis reduces splicing fidelity in mammalian cells. Nucleic Acids Res 2017; 45:6520-6529. [PMID: 28460122 PMCID: PMC5499639 DOI: 10.1093/nar/gkx339] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Splicing fidelity is essential to the maintenance of cellular functions and viability, and mutations or natural variations in pre-mRNA sequences and consequent alteration of splicing have been implicated in the etiology and progression of numerous diseases. The extent to which transcriptional errors or lesion-induced transcriptional mutagenesis (TM) influences splicing fidelity is not currently known. To investigate this, we employed site-specific DNA lesions on the transcribed strand of a minigene splicing reporter in normal mammalian cells. These were the common mutagenic lesions O6-methylguanine (O6-meG) and 8-oxoguanine (8-oxoG). The minigene splicing reporters were derived from lamin A (LMNA) and proteolipid protein 1 (PLP1), both with known links to human diseases that result from deregulated splicing. In cells with active DNA repair, 1–4% misincorporation occurred opposite the lesions, which increased to 20–40% when repair was compromised. Furthermore, our results reveal that TM at a splice site significantly reduces in vivo splicing fidelity, thereby changing the relative expression of alternative splicing forms in mammalian cells. These findings suggest that splicing defects caused by transcriptional errors can potentially lead to phenotypic cellular changes and increased susceptibility to the development of disease.
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Affiliation(s)
- João A Paredes
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Monika Ezerskyte
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Matteo Bottai
- Unit of Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Kristian Dreij
- Unit of Biochemical Toxicology, Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden
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49
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Wong HE, Huang CJ, Zhang Z. Amino acid misincorporation in recombinant proteins. Biotechnol Adv 2017; 36:168-181. [PMID: 29107148 DOI: 10.1016/j.biotechadv.2017.10.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/12/2017] [Accepted: 10/24/2017] [Indexed: 11/26/2022]
Abstract
Proteins provide the molecular basis for cellular structure, catalytic activity, signal transduction, and molecular transport in biological systems. Recombinant protein expression is widely used to prepare and manufacture novel proteins that serve as the foundation of many biopharmaceutical products. However, protein translation bioprocesses are inherently prone to low-level errors. These sequence variants caused by amino acid misincorporation have been observed in both native and recombinant proteins. Protein sequence variants impact product quality, and their presence can be exacerbated through cellular stress, overexpression, and nutrient starvation. Therefore, the cell line selection process, which is used in the biopharmaceutical industry, is not only directed towards maximizing productivity, but also focuses on selecting clones which yield low sequence variant levels, thereby proactively avoiding potentially inauspicious patient safety and efficacy outcomes. Here, we summarize a number of hallmark studies aimed at understanding the mechanisms of amino acid misincorporation, as well as exacerbating factors, and mitigation strategies. We also describe key advances in analytical technologies in the identification and quantification of sequence variants, and some practical considerations when using LC-MS/MS for detecting sequence variants.
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Affiliation(s)
- H Edward Wong
- Process Development, Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Chung-Jr Huang
- Process Development, Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Zhongqi Zhang
- Process Development, Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA 91320, United States.
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50
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The transcription fidelity factor GreA impedes DNA break repair. Nature 2017; 550:214-218. [PMID: 28976965 PMCID: PMC5654330 DOI: 10.1038/nature23907] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/07/2017] [Indexed: 01/07/2023]
Abstract
Homologous recombination repairs DNA double-strand breaks and must function even on actively transcribed DNA. Because break repair prevents chromosome loss, the completion of repair is expected to outweigh the transcription of broken templates. Yet, the interplay between DNA break repair and transcription processivity is unclear. Here we show that the transcription factor GreA inhibits break repair in Escherichia coli. GreA restarts backtracked RNA polymerase (RNAP) and hence promotes transcription fidelity. We report that removal of GreA results in dramatically enhanced break repair via the classical RecBCD-RecA pathway. Using a deep-sequencing method to measure chromosomal exonucleolytic degradation (XO-Seq), we demonstrate that the absence of GreA limits RecBCD-mediated resection. Our findings suggest that increased RNAP backtracking promotes break repair by instigating RecA loading by RecBCD, without the influence of canonical Chi signals. The idea that backtracked RNAP can stimulate recombination presents a DNA transaction conundrum: a transcription fidelity factor compromises genomic integrity.
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