1
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Qiu C, Arora P, Malik I, Laperuta AJ, Pavlovic EM, Ugochukwu S, Naik M, Kaplan CD. Thiolutin has complex effects in vivo but is a direct inhibitor of RNA polymerase II in vitro. Nucleic Acids Res 2024; 52:2546-2564. [PMID: 38214235 PMCID: PMC10954460 DOI: 10.1093/nar/gkad1258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 12/18/2023] [Accepted: 12/29/2023] [Indexed: 01/13/2024] Open
Abstract
Thiolutin is a natural product transcription inhibitor with an unresolved mode of action. Thiolutin and the related dithiolopyrrolone holomycin chelate Zn2+ and previous studies have concluded that RNA Polymerase II (Pol II) inhibition in vivo is indirect. Here, we present chemicogenetic and biochemical approaches to investigate thiolutin's mode of action in Saccharomyces cerevisiae. We identify mutants that alter sensitivity to thiolutin. We provide genetic evidence that thiolutin causes oxidation of thioredoxins in vivo and that thiolutin both induces oxidative stress and interacts functionally with multiple metals including Mn2+ and Cu2+, and not just Zn2+. Finally, we show direct inhibition of RNA polymerase II (Pol II) transcription initiation by thiolutin in vitro in support of classical studies that thiolutin can directly inhibit transcription in vitro. Inhibition requires both Mn2+ and appropriate reduction of thiolutin as excess DTT abrogates its effects. Pause prone, defective elongation can be observed in vitro if inhibition is bypassed. Thiolutin effects on Pol II occupancy in vivo are widespread but major effects are consistent with prior observations for Tor pathway inhibition and stress induction, suggesting that thiolutin use in vivo should be restricted to studies on its modes of action and not as an experimental tool.
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Affiliation(s)
- Chenxi Qiu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Payal Arora
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Indranil Malik
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | | | | | | | - Mandar Naik
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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2
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Pilotto S, Sýkora M, Cackett G, Dulson C, Werner F. Structure of the recombinant RNA polymerase from African Swine Fever Virus. Nat Commun 2024; 15:1606. [PMID: 38383525 PMCID: PMC10881513 DOI: 10.1038/s41467-024-45842-7] [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: 08/17/2023] [Accepted: 02/06/2024] [Indexed: 02/23/2024] Open
Abstract
African Swine Fever Virus is a Nucleo-Cytoplasmic Large DNA Virus that causes an incurable haemorrhagic fever in pigs with a high impact on global food security. ASFV replicates in the cytoplasm of the infected cell and encodes its own transcription machinery that is independent of cellular factors, however, not much is known about how this system works at a molecular level. Here, we present methods to produce recombinant ASFV RNA polymerase, functional assays to screen for inhibitors, and high-resolution cryo-electron microscopy structures of the ASFV RNAP in different conformational states. The ASFV RNAP bears a striking resemblance to RNAPII with bona fide homologues of nine of its twelve subunits. Key differences include the fusion of the ASFV assembly platform subunits RPB3 and RPB11, and an unusual C-terminal domain of the stalk subunit vRPB7 that is related to the eukaryotic mRNA cap 2´-O-methyltransferase 1. Despite the high degree of structural conservation with cellular RNA polymerases, the ASFV RNAP is resistant to the inhibitors rifampicin and alpha-amanitin. The cryo-EM structures and fully recombinant RNAP system together provide an important tool for the design, development, and screening of antiviral drugs in a low biosafety containment environment.
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Affiliation(s)
- Simona Pilotto
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Michal Sýkora
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Gwenny Cackett
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Christopher Dulson
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Finn Werner
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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3
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Duan B, Qiu C, Lockless SW, Sze SH, Kaplan CD. Higher-order epistasis within Pol II trigger loop haplotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576280. [PMID: 38293233 PMCID: PMC10827151 DOI: 10.1101/2024.01.20.576280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
RNA polymerase II (Pol II) has a highly conserved domain, the trigger loop (TL), that controls transcription fidelity and speed. We previously probed pairwise genetic interactions between residues within and surrounding the TL and identified widespread incompatibility between TLs of different species when placed in the Saccharomyces cerevisiae Pol II context, indicating epistasis between the TL and its surrounding context. We sought to understand the nature of this incompatibility and probe higher order epistasis internal to the TL. We have employed deep mutational scanning with selected natural TL variants ("haplotypes"), and all possible intermediate substitution combinations between them and the yeast Pol II TL. We identified both positive and negative higher-order residue interactions within example TL haplotypes. Intricate higher-order epistasis formed by TL residues was sometimes only apparent from analysis of intermediate genotypes, emphasizing complexity of epistatic interactions. Furthermore, we distinguished TL substitutions with distinct classes of epistatic patterns, suggesting specific TL residues that potentially influence TL evolution. Our examples of complex residue interactions suggest possible pathways for epistasis to facilitate Pol II evolution.
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Affiliation(s)
- Bingbing Duan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston, MA 02215
| | - Steve W Lockless
- Department of Biology, Texas A&M University, College Station, TX 77843
| | - Sing-Hoi Sze
- Department of Computer Science & Engineering, Texas A&M University, College Station, TX 77843
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
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4
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Chen X, Liu W, Wang Q, Wang X, Ren Y, Qu X, Li W, Xu Y. Structural visualization of transcription initiation in action. Science 2023; 382:eadi5120. [PMID: 38127763 DOI: 10.1126/science.adi5120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 11/11/2023] [Indexed: 12/23/2023]
Abstract
Transcription initiation is a complex process, and its mechanism is incompletely understood. We determined the structures of de novo transcribing complexes TC2 to TC17 with RNA polymerase II halted on G-less promoters when nascent RNAs reach 2 to 17 nucleotides in length, respectively. Connecting these structures generated a movie and a working model. As initially synthesized RNA grows, general transcription factors (GTFs) remain bound to the promoter and the transcription bubble expands. Nucleoside triphosphate (NTP)-driven RNA-DNA translocation and template-strand accumulation in a nearly sealed channel may promote the transition from initially transcribing complexes (ITCs) (TC2 to TC9) to early elongation complexes (EECs) (TC10 to TC17). Our study shows dynamic processes of transcription initiation and reveals why ITCs require GTFs and bubble expansion for initial RNA synthesis, whereas EECs need GTF dissociation from the promoter and bubble collapse for promoter escape.
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Affiliation(s)
- Xizi Chen
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
- The International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, China, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Weida Liu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Qianmin Wang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xinxin Wang
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yulei Ren
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xuechun Qu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Wanjun Li
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China
- The International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, China, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
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5
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Oh J, Shan Z, Hoshika S, Xu J, Chong J, Benner SA, Lyumkis D, Wang D. A unified Watson-Crick geometry drives transcription of six-letter expanded DNA alphabets by E. coli RNA polymerase. Nat Commun 2023; 14:8219. [PMID: 38086811 PMCID: PMC10716388 DOI: 10.1038/s41467-023-43735-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
Artificially Expanded Genetic Information Systems (AEGIS) add independently replicable unnatural nucleotide pairs to the natural G:C and A:T/U pairs found in native DNA, joining the unnatural pairs through alternative modes of hydrogen bonding. Whether and how AEGIS pairs are recognized and processed by multi-subunit cellular RNA polymerases (RNAPs) remains unknown. Here, we show that E. coli RNAP selectively recognizes unnatural nucleobases in a six-letter expanded genetic system. High-resolution cryo-EM structures of three RNAP elongation complexes containing template-substrate UBPs reveal the shared principles behind the recognition of AEGIS and natural base pairs. In these structures, RNAPs are captured in an active state, poised to perform the chemistry step. At this point, the unnatural base pair adopts a Watson-Crick geometry, and the trigger loop is folded into an active conformation, indicating that the mechanistic principles underlying recognition and incorporation of natural base pairs also apply to AEGIS unnatural base pairs. These data validate the design philosophy of AEGIS unnatural basepairs. Further, we provide structural evidence supporting a long-standing hypothesis that pair mismatch during transcription occurs via tautomerization. Together, our work highlights the importance of Watson-Crick complementarity underlying the design principles of AEGIS base pair recognition.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Pharmacy, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Zelin Shan
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Shuichi Hoshika
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, 13709 Progress Blvd Box 7, Alachua, FL, 32615, USA.
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute 10550 N Torrey Pines Road, La Jolla, CA, 92037, USA.
- Graduate School of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, 92093, USA.
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6
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Kim D, Lee MS, Kim ND, Lee S, Lee HS. Identification of α-amanitin effector proteins in hepatocytes by limited proteolysis-coupled mass spectrometry. Chem Biol Interact 2023; 386:110778. [PMID: 37879594 DOI: 10.1016/j.cbi.2023.110778] [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: 06/29/2023] [Revised: 10/02/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
The misuse of poisonous mushrooms containing amatoxins causes acute liver failure (ALF) in patients and is a cause of significant mortality. Although the toxic mechanisms of α-amanitin (α-AMA) and its interactions with RNA polymerase II (RNAP II) have been studied, α-AMA effector proteins that can interact with α-AMA in hepatocytes have not been systematically studied. Limited proteolysis-coupled mass spectrometry (LiP-MS) is an advanced technology that can quickly identify protein-ligand interactions based on global comparative proteomics. This study identified the α-AMA effector proteins found in human hepatocytes, following the detection of conformotypic peptides using LiP-MS coupled with tandem mass tag (TMT) technology. Proteins that are classified into protein processing in the endoplasmic reticulum and the ribosome during the KEGG pathway can be identified through affinity evaluation, according to α-AMA concentration-dependent LiP-MS and LiP-MS in hepatocytes derived from humans and mice, respectively. The possibility of interaction between α-AMA and proteins containing conformotypic peptides was evaluated through molecular docking studies. The results of this study suggest a novel path for α-AMA to induce hepatotoxicity through interactions with various proteins involved in protein synthesis, as well as with RNAP II.
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Affiliation(s)
- Doeun Kim
- College of Pharmacy, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Min Seo Lee
- BK21 Four-sponsored Advanced Program for SmartPharma Leaders, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea
| | - Nam Doo Kim
- Voronoibio Inc., Incheon, 21984, Republic of Korea
| | - Sangkyu Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
| | - Hye Suk Lee
- BK21 Four-sponsored Advanced Program for SmartPharma Leaders, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
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7
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Rasooly R, Do P, He X, Hernlem B. A Sensitive, Cell-Based Assay for Measuring Low-Level Biological Activity of α-Amanitin. Int J Mol Sci 2023; 24:16402. [PMID: 38003593 PMCID: PMC10671307 DOI: 10.3390/ijms242216402] [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: 10/11/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
α-Amanitin is one of the primary toxins produced by the poisonous mushroom genus, Amanita. Because it is odorless and tasteless, it is an important cause of death from the consumption of misidentified mushrooms. To study the thermal stability of α-amanitin, novel cell-based assays were developed to measure the toxin's activity, based on the inhibition of RNA polymerase II by α-amanitin. First, an MTT-formazan cell viability assay was used to measure the biological activity of α-amanitin through the inhibition of cellular activity. This method can detect 10 μg/mL of α-amanitin in a time-dependent manner. Second, a more sensitive quantitative PCR approach was developed to examine its inhibition of viral replication. The new RT-qPCR assay enabled the detection of 100 ng/mL. At this level, α-amanitin still significantly reduced adenovirus transcription. Third, a simpler GFP expression-based assay was developed with an equal sensitivity to the RT-qPCR assay. With this assay, aqueous α-amanitin heated at 90 °C for 16 h or treated in the microwave for 3 min retained its biological activity when tested in HEK293 cells, but a slight reduction was observed when tested in Vero cells. Beyond detecting the activity of α-amanitin, the new method has a potential application for detecting the activity of other toxins that are RNA polymerase inhibitors.
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Affiliation(s)
- Reuven Rasooly
- Foodborne Toxin Detection & Prevention Research Unit, Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, CA 94710, USA; (P.D.); (X.H.); (B.H.)
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8
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Wang Z, Li H, Gou L, Li W, Wang Y. Antibody-drug conjugates: Recent advances in payloads. Acta Pharm Sin B 2023; 13:4025-4059. [PMID: 37799390 PMCID: PMC10547921 DOI: 10.1016/j.apsb.2023.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/30/2023] [Accepted: 06/23/2023] [Indexed: 10/05/2023] Open
Abstract
Antibody‒drug conjugates (ADCs), which combine the advantages of monoclonal antibodies with precise targeting and payloads with efficient killing, show great clinical therapeutic value. The ADCs' payloads play a key role in determining the efficacy of ADC drugs and thus have attracted great attention in the field. An ideal ADC payload should possess sufficient toxicity, low immunogenicity, high stability, and modifiable functional groups. Common ADC payloads include tubulin inhibitors and DNA damaging agents, with tubulin inhibitors accounting for more than half of the ADC drugs in clinical development. However, due to clinical limitations of traditional ADC payloads, such as inadequate efficacy and the development of acquired drug resistance, novel highly efficient payloads with diverse targets and reduced side effects are being developed. This perspective summarizes the recent research advances of traditional and novel ADC payloads with main focuses on the structure-activity relationship studies, co-crystal structures, and designing strategies, and further discusses the future research directions of ADC payloads. This review also aims to provide valuable references and future directions for the development of novel ADC payloads that will have high efficacy, low toxicity, adequate stability, and abilities to overcome drug resistance.
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Affiliation(s)
- Zhijia Wang
- Department of Pulmonary and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu 610212, China
| | - Hanxuan Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Lantu Gou
- Department of Pulmonary and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Wei Li
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Yuxi Wang
- Department of Pulmonary and Critical Care Medicine, Targeted Tracer Research and Development Laboratory, Institute of Respiratory Health, Frontiers Science Center for Disease-related Molecular Network, National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, Precision Medicine Key Laboratory of Sichuan Province & Precision Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
- Frontiers Medical Center, Tianfu Jincheng Laboratory, Chengdu 610212, China
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9
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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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10
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Wang B, Wan AH, Xu Y, Zhang RX, Zhao BC, Zhao XY, Shi YC, Zhang X, Xue Y, Luo Y, Deng Y, Neely GG, Wan G, Wang QP. Identification of indocyanine green as a STT3B inhibitor against mushroom α-amanitin cytotoxicity. Nat Commun 2023; 14:2241. [PMID: 37193694 PMCID: PMC10188588 DOI: 10.1038/s41467-023-37714-3] [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: 07/07/2022] [Accepted: 03/21/2023] [Indexed: 05/18/2023] Open
Abstract
The "death cap", Amanita phalloides, is the world's most poisonous mushroom, responsible for 90% of mushroom-related fatalities. The most fatal component of the death cap is α-amanitin. Despite its lethal effect, the exact mechanisms of how α-amanitin poisons humans remain unclear, leading to no specific antidote available for treatment. Here we show that STT3B is required for α-amanitin toxicity and its inhibitor, indocyanine green (ICG), can be used as a specific antidote. By combining a genome-wide CRISPR screen with an in silico drug screening and in vivo functional validation, we discover that N-glycan biosynthesis pathway and its key component, STT3B, play a crucial role in α-amanitin toxicity and that ICG is a STT3B inhibitor. Furthermore, we demonstrate that ICG is effective in blocking the toxic effect of α-amanitin in cells, liver organoids, and male mice, resulting in an overall increase in animal survival. Together, by combining a genome-wide CRISPR screen for α-amanitin toxicity with an in silico drug screen and functional validation in vivo, our study highlights ICG as a STT3B inhibitor against the mushroom toxin.
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Affiliation(s)
- Bei Wang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Arabella H Wan
- Department of Pathology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, PR China
| | - Yu Xu
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Ruo-Xin Zhang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Ben-Chi Zhao
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Xin-Yuan Zhao
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yan-Chuan Shi
- Obesity and Metabolic Disease Research Group, Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia
| | - Xiaolei Zhang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China
| | - Yongbo Xue
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yong Luo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China
| | - G Gregory Neely
- Dr. John and Anne Chong Laboratory for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Guohui Wan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China.
| | - Qiao-Ping Wang
- Laboratory of Metabolism and Aging, School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, PR China.
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11
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Duan B, Qiu C, Sze SH, Kaplan C. Widespread epistasis shapes RNA Polymerase II active site function and evolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530048. [PMID: 36909581 PMCID: PMC10002619 DOI: 10.1101/2023.02.27.530048] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Multi-subunit RNA Polymerases (msRNAPs) are responsible for transcription in all kingdoms of life. At the heart of these msRNAPs is an ultra-conserved active site domain, the trigger loop (TL), coordinating transcription speed and fidelity by critical conformational changes impacting multiple steps in substrate selection, catalysis, and translocation. Previous studies have observed several different types of genetic interactions between eukaryotic RNA polymerase II (Pol II) TL residues, suggesting that the TL's function is shaped by functional interactions of residues within and around the TL. The extent of these interaction networks and how they control msRNAP function and evolution remain to be determined. Here we have dissected the Pol II TL interaction landscape by deep mutational scanning in Saccharomyces cerevisiae Pol II. Through analysis of over 15000 alleles, representing all single mutants, a rationally designed subset of double mutants, and evolutionarily observed TL haplotypes, we identify interaction networks controlling TL function. Substituting residues creates allele-specific networks and propagates epistatic effects across the Pol II active site. Furthermore, the interaction landscape further distinguishes alleles with similar growth phenotypes, suggesting increased resolution over the previously reported single mutant phenotypic landscape. Finally, co-evolutionary analyses reveal groups of co-evolving residues across Pol II converge onto the active site, where evolutionary constraints interface with pervasive epistasis. Our studies provide a powerful system to understand the plasticity of RNA polymerase mechanism and evolution, and provide the first example of pervasive epistatic landscape in a highly conserved and constrained domain within an essential enzyme.
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Affiliation(s)
- Bingbing Duan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston, MA 02215
| | - Sing-Hoi Sze
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX 77843
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843
| | - Craig Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
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12
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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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13
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Past, Present, and a Glance into the Future of Multiple Myeloma Treatment. Pharmaceuticals (Basel) 2023; 16:ph16030415. [PMID: 36986514 PMCID: PMC10056051 DOI: 10.3390/ph16030415] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023] Open
Abstract
Multiple myeloma (MM) is a challenging hematological cancer which typically grows in bone marrow. MM accounts for 10% of hematological malignancies and 1.8% of cancers. The recent treatment strategies have significantly improved progression-free survival for MM patients in the last decade; however, a relapse for most MM patients is inevitable. In this review we discuss current treatment, important pathways for proliferation, survival, immune suppression, and resistance that could be targeted for future treatments.
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14
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Dutagaci B, Duan B, Qiu C, Kaplan CD, Feig M. Characterization of RNA polymerase II trigger loop mutations using molecular dynamics simulations and machine learning. PLoS Comput Biol 2023; 19:e1010999. [PMID: 36947548 PMCID: PMC10069792 DOI: 10.1371/journal.pcbi.1010999] [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: 08/15/2022] [Revised: 04/03/2023] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Catalysis and fidelity of multisubunit RNA polymerases rely on a highly conserved active site domain called the trigger loop (TL), which achieves roles in transcription through conformational changes and interaction with NTP substrates. The mutations of TL residues cause distinct effects on catalysis including hypo- and hyperactivity and altered fidelity. We applied molecular dynamics simulation (MD) and machine learning (ML) techniques to characterize TL mutations in the Saccharomyces cerevisiae RNA Polymerase II (Pol II) system. We did so to determine relationships between individual mutations and phenotypes and to associate phenotypes with MD simulated structural alterations. Using fitness values of mutants under various stress conditions, we modeled phenotypes along a spectrum of continual values. We found that ML could predict the phenotypes with 0.68 R2 correlation from amino acid sequences alone. It was more difficult to incorporate MD data to improve predictions from machine learning, presumably because MD data is too noisy and possibly incomplete to directly infer functional phenotypes. However, a variational auto-encoder model based on the MD data allowed the clustering of mutants with different phenotypes based on structural details. Overall, we found that a subset of loss-of-function (LOF) and lethal mutations tended to increase distances of TL residues to the NTP substrate, while another subset of LOF and lethal substitutions tended to confer an increase in distances between TL and bridge helix (BH). In contrast, some of the gain-of-function (GOF) mutants appear to cause disruption of hydrophobic contacts among TL and nearby helices.
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Affiliation(s)
- Bercem Dutagaci
- Department of Molecular and Cell Biology, University of California Merced, Merced, California, United States of America
| | - Bingbing Duan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Craig D. Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, United States of America
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15
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Unarta IC, Goonetilleke EC, Wang D, Huang X. Nucleotide addition and cleavage by RNA polymerase II: Coordination of two catalytic reactions using a single active site. J Biol Chem 2022; 299:102844. [PMID: 36581202 PMCID: PMC9860460 DOI: 10.1016/j.jbc.2022.102844] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
RNA polymerase II (Pol II) incorporates complementary ribonucleotides into the growing RNA chain one at a time via the nucleotide addition cycle. The nucleotide addition cycle, however, is prone to misincorporation of noncomplementary nucleotides. Thus, to ensure transcriptional fidelity, Pol II backtracks and then cleaves the misincorporated nucleotides. These two reverse reactions, nucleotide addition and cleavage, are catalyzed in the same active site of Pol II, which is different from DNA polymerases or other endonucleases. Recently, substantial progress has been made to understand how Pol II effectively performs its dual role in the same active site. Our review highlights these recent studies and provides an overall model of the catalytic mechanisms of Pol II. In particular, RNA extension follows the two-metal-ion mechanism, and several Pol II residues play important roles to facilitate the catalysis. In sharp contrast, the cleavage reaction is independent of any Pol II residues. Interestingly, Pol II relies on its residues to recognize the misincorporated nucleotides during the backtracking process, prior to cleavage. In this way, Pol II efficiently compartmentalizes its two distinct catalytic functions using the same active site. Lastly, we also discuss a new perspective on the potential third Mg2+ in the nucleotide addition and intrinsic cleavage reactions.
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Affiliation(s)
- Ilona Christy Unarta
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eshani C Goonetilleke
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Dong Wang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
| | - Xuhui Huang
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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16
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Anti-CD37 α-amanitin-conjugated antibodies as potential therapeutic weapons for Richter syndrome. Blood 2022; 140:1565-1569. [PMID: 35914223 PMCID: PMC9523372 DOI: 10.1182/blood.2022016211] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 07/09/2022] [Indexed: 11/20/2022] Open
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17
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How to Shut Down Transcription in Archaea during Virus Infection. Microorganisms 2022; 10:microorganisms10091824. [PMID: 36144426 PMCID: PMC9501531 DOI: 10.3390/microorganisms10091824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/16/2022] Open
Abstract
Multisubunit RNA polymerases (RNAPs) carry out transcription in all domains of life; during virus infection, RNAPs are targeted by transcription factors encoded by either the cell or the virus, resulting in the global repression of transcription with distinct outcomes for different host–virus combinations. These repressors serve as versatile molecular probes to study RNAP mechanisms, as well as aid the exploration of druggable sites for the development of new antibiotics. Here, we review the mechanisms and structural basis of RNAP inhibition by the viral repressor RIP and the crenarchaeal negative regulator TFS4, which follow distinct strategies. RIP operates by occluding the DNA-binding channel and mimicking the initiation factor TFB/TFIIB. RIP binds tightly to the clamp and locks it into one fixed position, thereby preventing conformational oscillations that are critical for RNAP function as it progresses through the transcription cycle. TFS4 engages with RNAP in a similar manner to transcript cleavage factors such as TFS/TFIIS through the NTP-entry channel; TFS4 interferes with the trigger loop and bridge helix within the active site by occlusion and allosteric mechanisms, respectively. The conformational changes in RNAP described above are universally conserved and are also seen in inactive dimers of eukaryotic RNAPI and several inhibited RNAP complexes of both bacterial and eukaryotic RNA polymerases, including inactive states that precede transcription termination. A comparison of target sites and inhibitory mechanisms reveals that proteinaceous repressors and RNAP-specific antibiotics use surprisingly common ways to inhibit RNAP function.
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18
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Bozukova M, Nikopoulou C, Kleinenkuhnen N, Grbavac D, Goetsch K, Tessarz P. Aging is associated with increased chromatin accessibility and reduced polymerase pausing in liver. Mol Syst Biol 2022; 18:e11002. [PMID: 36082605 PMCID: PMC9459415 DOI: 10.15252/msb.202211002] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/29/2022] Open
Abstract
Regulation of gene expression is linked to the organization of the genome. With age, chromatin alterations occur on all levels of genome organization, accompanied by changes in the gene expression profile. However, little is known about the changes in the level of transcriptional regulation. Here, we used a multi‐omics approach and integrated ATAC‐, RNA‐ and NET‐seq to identify age‐related changes in the chromatin landscape of murine liver and to investigate how these are linked to transcriptional regulation. We provide the first systematic inventory of the connection between aging, chromatin accessibility, and transcriptional regulation in a whole tissue. Aging in murine liver is characterized by an increase in chromatin accessibility at promoter regions, but not in an increase in transcriptional output. Instead, aging is accompanied by a decrease in promoter‐proximal pausing of RNA polymerase II (Pol II), while initiation of transcription is not decreased as assessed by RNA polymerase mapping using CUT&RUN. Based on the data reported, we propose that these age‐related changes in transcriptional regulation are due to a reduced stability of the pausing complex.
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Affiliation(s)
- Mihaela Bozukova
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Chrysa Nikopoulou
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Niklas Kleinenkuhnen
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany.,Faculty of Medicine, Institute of Medical Statistics and Computational Biology, University of Cologne, Cologne, Germany
| | - Dora Grbavac
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Katrin Goetsch
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Peter Tessarz
- Max Planck Research Group 'Chromatin and Ageing', Max Planck Institute for Biology of Ageing, Cologne, Germany.,Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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19
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Ford RE, Foster GD, Bailey AM. Exploring fungal RiPPs from the perspective of chemical ecology. Fungal Biol Biotechnol 2022; 9:12. [PMID: 35752794 PMCID: PMC9233826 DOI: 10.1186/s40694-022-00144-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/05/2022] [Indexed: 12/31/2022] Open
Abstract
Since the initial detection, in 2007, of fungal ribosomally synthesised and post-translationally modified peptides (RiPPs), this group of natural products has undergone rapid expansion, with four separate classes now recognised: amatoxins/phallotoxins, borosins, dikaritins, and epichloëcyclins. Largely due to their historically anthropocentric employment in medicine and agriculture, novel fungal proteins and peptides are seldom investigated in relation to the fungus itself. Therefore, although the benefits these compounds confer to humans are often realised, their evolutionary advantage to the fungus, the reason for their continued production, is often obscure or ignored. This review sets out to summarise current knowledge on how these small peptide-derived products influence their producing species and surrounding biotic environment.
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Affiliation(s)
- R E Ford
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK
| | - G D Foster
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK
| | - A M Bailey
- School of Biological Sciences, University of Bristol, Life Sciences Building, 28 Tyndall Ave, Bristol, BS8 1TQ, UK.
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20
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Garcia J, Carvalho A, das Neves RP, Malheiro R, Rodrigues DF, Figueiredo PR, Bovolini A, Duarte JA, Costa VM, Carvalho F. Antidotal effect of cyclosporine A against α-amanitin toxicity in CD-1 mice, at clinical relevant doses. Food Chem Toxicol 2022; 166:113198. [PMID: 35671903 DOI: 10.1016/j.fct.2022.113198] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 05/25/2022] [Accepted: 05/30/2022] [Indexed: 12/12/2022]
Abstract
Amanita phalloides is one of the most toxic mushrooms worldwide, being responsible for the majority of human fatal cases of mushroom intoxications. α-Amanitin, the most deleterious toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and renal failure. Herein, we used cyclosporine A after it showed potential to displace RNAP II α-amanitin in silico. That potential was not confirmed either by the incorporation of ethynyl-UTP or by the monitoring of fluorescent RNAP II levels. Nevertheless, concomitant incubation of cyclosporine A with α-amanitin, for a short period, provided significant protection against its toxicity in differentiated HepaRG cells. In mice, the concomitant administration of α-amanitin [0.45 mg/kg intraperitoneal (i.p.)] with cyclosporine A (10 mg/kg i.p. plus 2 × 10 mg/kg cyclosporine A i.p. at 8 and 12 h post α-amanitin) resulted in the full survival of α-amanitin-intoxicated mice, up to 30 days after the toxin's administration. Since α-amanitin is a substrate of the organic-anion-transporting polypeptide 1B3 and cyclosporine A inhibits this transporter and is a potent anti-inflammatory agent, we hypothesize that these mechanisms are responsible for the protection observed. These results indicate a potential antidotal effect of cyclosporine A, and its safety profile advocates for its use at an early stage of α-amanitin intoxications.
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Affiliation(s)
- Juliana Garcia
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal; Laboratório Associado i4HB - Instituto para a Saúde e a Bioeconomia, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal
| | - Alexandra Carvalho
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal; IIIUC-Institute of Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal
| | - Ricardo Pires das Neves
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
| | - Rui Malheiro
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal; Laboratório Associado i4HB - Instituto para a Saúde e a Bioeconomia, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal
| | - Daniela F Rodrigues
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal; Laboratório Associado i4HB - Instituto para a Saúde e a Bioeconomia, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal
| | - Pedro R Figueiredo
- CNC - Center for Neuroscience and Cell Biology, CIBB - Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-517, Coimbra, Portugal
| | | | - José Alberto Duarte
- CIAFEL, Faculty of Sport, University of Porto, Porto, Portugal; TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116, Gandra, Portugal
| | - Vera Marisa Costa
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal; Laboratório Associado i4HB - Instituto para a Saúde e a Bioeconomia, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal.
| | - Félix Carvalho
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal; Laboratório Associado i4HB - Instituto para a Saúde e a Bioeconomia, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal.
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21
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Suzuki H, Abe R, Shimada M, Hirose T, Hirose H, Noguchi K, Ike Y, Yasui N, Furugori K, Yamaguchi Y, Toyoda A, Suzuki Y, Yamamoto T, Saitoh N, Sato S, Tomomori-Sato C, Conaway RC, Conaway JW, Takahashi H. The 3' Pol II pausing at replication-dependent histone genes is regulated by Mediator through Cajal bodies' association with histone locus bodies. Nat Commun 2022; 13:2905. [PMID: 35614107 PMCID: PMC9133132 DOI: 10.1038/s41467-022-30632-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/10/2022] [Indexed: 11/09/2022] Open
Abstract
Non-polyadenylated mRNAs of replication-dependent histones (RDHs) are synthesized by RNA polymerase II (Pol II) at histone locus bodies (HLBs). HLBs frequently associate with Cajal bodies (CBs), in which 3'-end processing factors for RDH genes are enriched; however, this association's role in transcription termination of RDH genes remains unclear. Here, we show that Pol II pauses immediately upstream of transcript end sites of RDH genes and Mediator plays a role in this Pol II pausing through CBs' association with HLBs. Disruption of the Mediator docking site for Little elongation complex (LEC)-Cap binding complex (CBC)-Negative elongation factor (NELF), components of CBs, interferes with CBs' association with HLBs and 3' Pol II pausing, resulting in increased aberrant unprocessed RDH gene transcripts. Our findings suggest Mediator's involvement in CBs' association with HLBs to facilitate 3' Pol II pausing and subsequent 3'-end processing of RDH genes by supplying 3'-end processing factors.
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Affiliation(s)
- Hidefumi Suzuki
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Ryota Abe
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Miho Shimada
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Tomonori Hirose
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Hiroko Hirose
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Keisuke Noguchi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Yoko Ike
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Nanami Yasui
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Kazuki Furugori
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan
| | - Yuki Yamaguchi
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama, Kanagawa, 226-8501, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Yutaka Suzuki
- Laboratory of Systems Genomics, Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan
| | - Tatsuro Yamamoto
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Shigeo Sato
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA
| | - Chieri Tomomori-Sato
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA
| | - Ronald C Conaway
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA.,Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, MO, 66160, USA
| | - Joan W Conaway
- Stowers Institute for Medical Research, 1000E 50th Street, Kansas City, MO, 64110, USA.,Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, MO, 66160, USA
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University Graduate School of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa, 236-0004, Japan.
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22
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Gu X, Zhang L, Sun W, Liu K, Xu H, Wu P, Gui M, Qu W. Autophagy Promotes α-Amanitin-Induced Apoptosis of Hepa1-6 Liver Cells. Chem Res Toxicol 2022; 35:392-401. [PMID: 35175747 DOI: 10.1021/acs.chemrestox.1c00297] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is estimated that 90% of deaths from food poisoning in China can be attributed to Amanita poisoning, whose main toxin is α-amanitin. Studies showed that apoptosis plays a critical role in liver injuries induced by α-amanitin. Although the relationship between autophagy and apoptosis in different liver models has been addressed many times, whether autophagy plays a pro or con effect on α-amanitin-induced apoptosis has not been clarified. Therefore, this study was conducted to explore the effect of autophagy in α-amanitin-induced apoptosis in Hepa1-6 liver cells. A 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was applied to determine cell viability, a 2',7'-dichlorofluorescin diacetate probe was used to monitor reactive oxygen species (ROS) levels, a flow cytometer and dansylcadaverine (MDC) staining were used to observe α-amanitin-induced apoptosis and autophagy, respectively, and apoptosis and autophagy proteins were assessed by western blotting. The results showed that α-amanitin suppressed cell viability in a time- and concentration-dependent manner. Moreover, the release of ROS was increased with increasing α-amanitin amount. Cell apoptosis and autophagy were noticed and characterized by the increased apoptosis rate and autophagic vesicles under a fluorescence microscope as well as upregulation of Bax/Bcl-2, cleaved caspase-3, and LC3-II/I and downregulation of p62. Further, the autophagy activator rapamycin (Rap) and the inhibitor 3-methylademine (3-MA) were introduced, which showed that the apoptosis rate and the ratio of Bax/Bcl-2 as well as the protein expression level of cleaved caspase-3 increased significantly with the pretreatment of Rap and decreased remarkably with the pretreatment of 3-MA. Moreover, cell viability was found to decrease further with the promotion of autophagy. Notably, the ROS level was attenuated after autophagy was elevated. In conclusion, autophagy could promote α-amanitin-induced Hepa1-6 cell apoptosis, and the process is unassociated with ROS levels. This research provides a theoretical basis for the study of the toxicological mechanism of α-amanitin-induced liver injuries.
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Affiliation(s)
- Xiaolong Gu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
| | - Limei Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
| | - Weixing Sun
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
| | - Kai Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
| | - Hui Xu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
| | - Peng Wu
- Yunnan Plateau Characteristic Agricultural Industry Research Institute, Yunnan Agricultural University, Kunming 650201, Yunnan, P. R. China
| | - Mingying Gui
- Yunnan Plateau Characteristic Agricultural Industry Research Institute, Yunnan Agricultural University, Kunming 650201, Yunnan, P. R. China
| | - Weijie Qu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Yunnan Agricultural University, No. 65, Jin Hei Road, Panlong District, Kunming 650051, P. R. China
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23
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Katirci Y, Yilmaz I, Kaya E. Effects of thymoquinone on alpha-amanitin induced hepatotoxicity in human C3A hepatocytes. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e191072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - Ismail Yilmaz
- Izmir Kâtip Celebi University School of Medicine, Turkey
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24
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Agapov A, Olina A, Kulbachinskiy A. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3018-3041. [PMID: 35323981 PMCID: PMC8989532 DOI: 10.1093/nar/gkac174] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 02/26/2022] [Accepted: 03/03/2022] [Indexed: 11/14/2022] Open
Abstract
Cellular DNA is continuously transcribed into RNA by multisubunit RNA polymerases (RNAPs). The continuity of transcription can be disrupted by DNA lesions that arise from the activities of cellular enzymes, reactions with endogenous and exogenous chemicals or irradiation. Here, we review available data on translesion RNA synthesis by multisubunit RNAPs from various domains of life, define common principles and variations in DNA damage sensing by RNAP, and consider existing controversies in the field of translesion transcription. Depending on the type of DNA lesion, it may be correctly bypassed by RNAP, or lead to transcriptional mutagenesis, or result in transcription stalling. Various lesions can affect the loading of the templating base into the active site of RNAP, or interfere with nucleotide binding and incorporation into RNA, or impair RNAP translocation. Stalled RNAP acts as a sensor of DNA damage during transcription-coupled repair. The outcome of DNA lesion recognition by RNAP depends on the interplay between multiple transcription and repair factors, which can stimulate RNAP bypass or increase RNAP stalling, and plays the central role in maintaining the DNA integrity. Unveiling the mechanisms of translesion transcription in various systems is thus instrumental for understanding molecular pathways underlying gene regulation and genome stability.
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Affiliation(s)
- Aleksei Agapov
- Correspondence may also be addressed to Aleksei Agapov. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
| | - Anna Olina
- Institute of Molecular Genetics, National Research Center “Kurchatov Institute” Moscow 123182, Russia
| | - Andrey Kulbachinskiy
- To whom correspondence should be addressed. Tel: +7 499 196 0015; Fax: +7 499 196 0015;
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25
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Connell Z, Parnell TJ, McCullough LL, Hill CP, Formosa T. The interaction between the Spt6-tSH2 domain and Rpb1 affects multiple functions of RNA Polymerase II. Nucleic Acids Res 2021; 50:784-802. [PMID: 34967414 PMCID: PMC8789061 DOI: 10.1093/nar/gkab1262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 11/29/2021] [Accepted: 12/09/2021] [Indexed: 11/21/2022] Open
Abstract
The conserved transcription elongation factor Spt6 makes several contacts with the RNA Polymerase II (RNAPII) complex, including a high-affinity interaction between the Spt6 tandem SH2 domain (Spt6-tSH2) and phosphorylated residues of the Rpb1 subunit in the linker between the catalytic core and the C-terminal domain (CTD) heptad repeats. This interaction contributes to generic localization of Spt6, but we show here that it also has gene-specific roles. Disrupting the interface affected transcription start site selection at a subset of genes whose expression is regulated by this choice, and this was accompanied by changes in a distinct pattern of Spt6 accumulation at these sites. Splicing efficiency was also diminished, as was apparent progression through introns that encode snoRNAs. Chromatin-mediated repression was impaired, and a distinct role in maintaining +1 nucleosomes was identified, especially at ribosomal protein genes. The Spt6-tSH2:Rpb1 interface therefore has both genome-wide functions and local roles at subsets of genes where dynamic decisions regarding initiation, transcript processing, or termination are made. We propose that the interaction modulates the availability or activity of the core elongation and histone chaperone functions of Spt6, contributing to coordination between RNAPII and its accessory factors as varying local conditions call for dynamic responses.
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Affiliation(s)
- Zaily Connell
- Dept of Biochemistry, University of Utah School of Medicine 15 N Medical Drive, Rm 4100, Salt Lake City, UT 84112, USA
| | - Timothy J Parnell
- Huntsman Cancer Institute, 2000 Circle of Hope, Salt Lake City, UT 84112, USA
| | - Laura L McCullough
- Dept of Biochemistry, University of Utah School of Medicine 15 N Medical Drive, Rm 4100, Salt Lake City, UT 84112, USA
| | - Christopher P Hill
- Dept of Biochemistry, University of Utah School of Medicine 15 N Medical Drive, Rm 4100, Salt Lake City, UT 84112, USA
| | - Tim Formosa
- Dept of Biochemistry, University of Utah School of Medicine 15 N Medical Drive, Rm 4100, Salt Lake City, UT 84112, USA
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26
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Palo MZ, Zhu J, Mishanina TV, Landick R. Conserved Trigger Loop Histidine of RNA Polymerase II Functions as a Positional Catalyst Primarily through Steric Effects. Biochemistry 2021; 60:3323-3336. [PMID: 34705427 DOI: 10.1021/acs.biochem.1c00528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In all domains of life, multisubunit RNA polymerases (RNAPs) catalyze both the extension of mRNA transcripts by nucleotide addition and the hydrolysis of RNA, which enables proofreading by removal of misincorporated nucleotides. A highly conserved catalytic module within RNAPs called the trigger loop (TL) functions as the key controller of these activities. The TL is proposed to act as a positional catalyst of phosphoryl transfer and transcript cleavage via electrostatic and steric contacts with substrates in its folded helical form. The function of a near-universally conserved TL histidine that contacts NTP phosphates is of particular interest. Despite its exceptional conservation, substitutions of the TL His with Gln support efficient catalysis in bacterial and yeast RNAPs. Unlike bacterial TLs, which contain a nearby Arg, the TL His is the only acid-base catalyst candidate in the eukaryotic RNAPII TL. Nonetheless, replacement of the TL His with Leu is reported to support cell growth in yeast, suggesting that even hydrogen bonding and polarity at this position may be dispensable for efficient catalysis by RNAPII. To test how a TL His-to-Leu substitution affects the enzymatic functions of RNAPII, we compared its rates of nucleotide addition, pyrophosphorolysis, and RNA hydrolysis to those of the wild-type RNAPII enzyme. The His-to-Leu substitution slightly reduced rates of phosphoryl transfer with little if any effect on intrinsic transcript cleavage. These findings indicate that the highly conserved TL His is neither an obligate acid-base catalyst nor a polar contact for NTP phosphates but instead functions as a positional catalyst mainly through steric effects.
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Affiliation(s)
- Michael Z Palo
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Junqiao Zhu
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Tatiana V Mishanina
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.,Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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27
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Zhao T, Vvedenskaya IO, Lai WKM, Basu S, Pugh BF, Nickels BE, Kaplan CD. Ssl2/TFIIH function in transcription start site scanning by RNA polymerase II in Saccharomyces cerevisiae. eLife 2021; 10:e71013. [PMID: 34652274 PMCID: PMC8589449 DOI: 10.7554/elife.71013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/14/2021] [Indexed: 12/31/2022] Open
Abstract
In Saccharomyces cerevisiae, RNA polymerase II (Pol II) selects transcription start sites (TSSs) by a unidirectional scanning process. During scanning, a preinitiation complex (PIC) assembled at an upstream core promoter initiates at select positions within a window ~40-120 bp downstream. Several lines of evidence indicate that Ssl2, the yeast homolog of XPB and an essential and conserved subunit of the general transcription factor (GTF) TFIIH, drives scanning through its DNA-dependent ATPase activity, therefore potentially controlling both scanning rate and scanning extent (processivity). To address questions of how Ssl2 functions in promoter scanning and interacts with other initiation activities, we leveraged distinct initiation-sensitive reporters to identify novel ssl2 alleles. These ssl2 alleles, many of which alter residues conserved from yeast to human, confer either upstream or downstream TSS shifts at the model promoter ADH1 and genome-wide. Specifically, tested ssl2 alleles alter TSS selection by increasing or narrowing the distribution of TSSs used at individual promoters. Genetic interactions of ssl2 alleles with other initiation factors are consistent with ssl2 allele classes functioning through increasing or decreasing scanning processivity but not necessarily scanning rate. These alleles underpin a residue interaction network that likely modulates Ssl2 activity and TFIIH function in promoter scanning. We propose that the outcome of promoter scanning is determined by two functional networks, the first being Pol II activity and factors that modulate it to determine initiation efficiency within a scanning window, and the second being Ssl2/TFIIH and factors that modulate scanning processivity to determine the width of the scanning widow.
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Affiliation(s)
- Tingting Zhao
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
| | - Irina O Vvedenskaya
- Department of Genetics and Waksman Institute, Rutgers UniversityPiscatawayUnited States
| | - William KM Lai
- Department of Molecular Biology and Genetics, Cornell UniversityIthacaUnited States
| | - Shrabani Basu
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
| | - B Franklin Pugh
- Department of Molecular Biology and Genetics, Cornell UniversityIthacaUnited States
| | - Bryce E Nickels
- Department of Genetics and Waksman Institute, Rutgers UniversityPiscatawayUnited States
| | - Craig D Kaplan
- Department of Biological Sciences, University of PittsburghPittsburghUnited States
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28
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Matinkhoo K, Pryyma A, Wong AAWL, Perrin DM. Synthesis and evaluation of " Ama-Flash", a photocaged amatoxin prodrug for light-activated RNA Pol II inhibition and cell death. Chem Commun (Camb) 2021; 57:9558-9561. [PMID: 34477193 DOI: 10.1039/d1cc03279h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Amanitin is used extensively as a research tool to inhibit RNA Pol II thereby implicating its role in mRNA transcription. Recently, amanitin has gained traction as a toxic payload for targeted therapy. Here we report the first-ever photocaged amanitin analog, that is non-toxic and can be pre-loaded into cells. Light provides a means to inhibit RNA Pol II and provoke cell death on-demand.
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Affiliation(s)
- Kaveh Matinkhoo
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
| | - Alla Pryyma
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
| | - Antonio A W L Wong
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
| | - David M Perrin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada.
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29
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Obligate movements of an active site-linked surface domain control RNA polymerase elongation and pausing via a Phe pocket anchor. Proc Natl Acad Sci U S A 2021; 118:2101805118. [PMID: 34470825 DOI: 10.1073/pnas.2101805118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The catalytic trigger loop (TL) in RNA polymerase (RNAP) alternates between unstructured and helical hairpin conformations to admit and then contact the NTP substrate during transcription. In many bacterial lineages, the TL is interrupted by insertions of two to five surface-exposed, sandwich-barrel hybrid motifs (SBHMs) of poorly understood function. The 188-amino acid, two-SBHM insertion in Escherichia coli RNAP, called SI3, occupies different locations in elongating, NTP-bound, and paused transcription complexes, but its dynamics during active transcription and pausing are undefined. Here, we report the design, optimization, and use of a Cys-triplet reporter to measure the positional bias of SI3 in different transcription complexes and to determine the effect of restricting SI3 movement on nucleotide addition and pausing. We describe the use of H2O2 as a superior oxidant for RNAP disulfide reporters. NTP binding biases SI3 toward the closed conformation, whereas transcriptional pausing biases SI3 toward a swiveled position that inhibits TL folding. We find that SI3 must change location in every round of nucleotide addition and that restricting its movements inhibits both transcript elongation and pausing. These dynamics are modulated by a crucial Phe pocket formed by the junction of the two SBHM domains. This SI3 Phe pocket captures a Phe residue in the RNAP jaw when the TL unfolds, explaining the similar phenotypes of alterations in the jaw and SI3. Our findings establish that SI3 functions by modulating TL folding to aid transcriptional regulation and to reset secondary channel trafficking in every round of nucleotide addition.
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30
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Kudruk S, Pottanam Chali S, Linard Matos AL, Bourque C, Dunker C, Gatsogiannis C, Ravoo BJ, Gerke V. Biodegradable and Dual-Responsive Polypeptide-Shelled Cyclodextrin-Containers for Intracellular Delivery of Membrane-Impermeable Cargo. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100694. [PMID: 34278745 PMCID: PMC8456233 DOI: 10.1002/advs.202100694] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 07/01/2021] [Indexed: 06/08/2023]
Abstract
The transport of membrane impermeable compounds into cells is a prerequisite for the efficient cellular delivery of hydrophilic and amphiphilic compounds and drugs. Transport into the cell's cytosolic compartment should ideally be controllable and it should involve biologically compatible and degradable vehicles. Addressing these challenges, nanocontainers based on cyclodextrin amphiphiles that are stabilized by a biodegradable peptide shell are developed and their potential to deliver fluorescently labeled cargo into human cells is analyzed. Host-guest mediated self-assembly of a thiol-containing short peptide or a cystamine-cross-linked polypeptide shell on cyclodextrin vesicles produce short peptide-shelled (SPSVss ) or polypeptide-shelled vesicles (PPSVss ), respectively, with redox-responsive and biodegradable features. Whereas SPSVss are permeable and less stable, PPSVss effectively encapsulate cargo and show a strictly regulated release of membrane impermeable cargo triggered by either reducing conditions or peptidase treatment. Live cell experiments reveal that the novel PPSVSS are readily internalized by primary human endothelial cells (human umbilical vein endothelial cells) and cervical cancer cells and that the reductive microenvironment of the cells' endosomes trigger release of the hydrophilic cargo into the cytosol. Thus, PPSVSS represent a highly efficient, biodegradable, and tunable system for overcoming the plasma membrane as a natural barrier for membrane-impermeable cargo.
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Affiliation(s)
- Sergej Kudruk
- Institute of Medical BiochemistryCenter for Molecular Biology of InflammationUniversity of MuensterVon‐Esmarch‐Str. 56Münster48149Germany
| | - Sharafudheen Pottanam Chali
- Center for Soft Nanoscience and Organic Chemistry InstituteUniversity of MuensterBusso Peus Straße 10Münster48149Germany
| | - Anna Livia Linard Matos
- Institute of Medical BiochemistryCenter for Molecular Biology of InflammationUniversity of MuensterVon‐Esmarch‐Str. 56Münster48149Germany
| | - Cole Bourque
- Center for Soft Nanoscience and Institute of Medical Physics and BiophysicsUniversity of MuensterBusso Peus Straße 10Münster48149Germany
- Max Planck Institute of Molecular PhysiologyOtto‐Hahn‐Straße 11Dortmund44227Germany
| | - Clara Dunker
- Institute of Medical BiochemistryCenter for Molecular Biology of InflammationUniversity of MuensterVon‐Esmarch‐Str. 56Münster48149Germany
| | - Christos Gatsogiannis
- Center for Soft Nanoscience and Institute of Medical Physics and BiophysicsUniversity of MuensterBusso Peus Straße 10Münster48149Germany
- Max Planck Institute of Molecular PhysiologyOtto‐Hahn‐Straße 11Dortmund44227Germany
| | - Bart Jan Ravoo
- Center for Soft Nanoscience and Organic Chemistry InstituteUniversity of MuensterBusso Peus Straße 10Münster48149Germany
| | - Volker Gerke
- Institute of Medical BiochemistryCenter for Molecular Biology of InflammationUniversity of MuensterVon‐Esmarch‐Str. 56Münster48149Germany
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31
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Cao L, Do T, Link AJ. Mechanisms of action of ribosomally synthesized and posttranslationally modified peptides (RiPPs). J Ind Microbiol Biotechnol 2021; 48:6121428. [PMID: 33928382 PMCID: PMC8183687 DOI: 10.1093/jimb/kuab005] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/22/2021] [Indexed: 12/19/2022]
Abstract
Natural products remain a critical source of medicines and drug leads. One of the most rapidly growing superclasses of natural products is RiPPs: ribosomally synthesized and posttranslationally modified peptides. RiPPs have rich and diverse bioactivities. This review highlights examples of the molecular mechanisms of action that underly those bioactivities. Particular emphasis is placed on RiPP/target interactions for which there is structural information. This detailed mechanism of action work is critical toward the development of RiPPs as therapeutics and can also be used to prioritize hits in RiPP genome mining studies.
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Affiliation(s)
- Li Cao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Truc Do
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - A James Link
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.,Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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32
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Matinkhoo K, Wong AAWL, Hambira CM, Kato B, Wei C, Müller C, Hechler T, Braun A, Gallo F, Pahl A, Perrin DM. Design, Synthesis, and Biochemical Evaluation of Alpha-Amanitin Derivatives Containing Analogs of the trans-Hydroxyproline Residue for Potential Use in Antibody-Drug Conjugates. Chemistry 2021; 27:10282-10292. [PMID: 34058032 DOI: 10.1002/chem.202101373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Indexed: 01/08/2023]
Abstract
Alpha-amanitin, an extremely toxic bicyclic octapeptide extracted from the death-cap mushroom, Amanita phalloides, is a highly selective allosteric inhibitor of RNA polymerase II. Following on growing interest in using this toxin as a payload in antibody-drug conjugates, herein we report the synthesis and biochemical evaluation of several new derivatives of this toxin to probe the role of the trans-hydroxyproline (Hyp), which is known to be critical for toxicity. This structure activity relationship (SAR) study represents the first of its kind to use various Hyp-analogs to alter the conformational and H-bonding properties of Hyp in amanitin.
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Affiliation(s)
- Kaveh Matinkhoo
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Antonio A W L Wong
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Chido M Hambira
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Brandon Kato
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Charlie Wei
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
| | - Christoph Müller
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Torsten Hechler
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Alexandra Braun
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Francesca Gallo
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - Andreas Pahl
- Heidelberg Pharma, Gregor-Mendel-Straße 22, 68526, Ladenburg, Germany
| | - David M Perrin
- Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T-1Z1, Canada
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33
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Muniz L, Nicolas E, Trouche D. RNA polymerase II speed: a key player in controlling and adapting transcriptome composition. EMBO J 2021; 40:e105740. [PMID: 34254686 PMCID: PMC8327950 DOI: 10.15252/embj.2020105740] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 05/01/2021] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
RNA polymerase II (RNA Pol II) speed or elongation rate, i.e., the number of nucleotides synthesized per unit of time, is a major determinant of transcriptome composition. It controls co‐transcriptional processes such as splicing, polyadenylation, and transcription termination, thus regulating the production of alternative splice variants, circular RNAs, alternatively polyadenylated transcripts, or read‐through transcripts. RNA Pol II speed itself is regulated in response to intra‐ and extra‐cellular stimuli and can in turn affect the transcriptome composition in response to these stimuli. Evidence points to a potentially important role of transcriptome composition modification through RNA Pol II speed regulation for adaptation of cells to a changing environment, thus pointing to a function of RNA Pol II speed regulation in cellular physiology. Analyzing RNA Pol II speed dynamics may therefore be central to fully understand the regulation of physiological processes, such as the development of multicellular organisms. Recent findings also raise the possibility that RNA Pol II speed deregulation can be detrimental and participate in disease progression. Here, we review initial and current approaches to measure RNA Pol II speed, as well as providing an overview of the factors controlling speed and the co‐transcriptional processes which are affected. Finally, we discuss the role of RNA Pol II speed regulation in cell physiology.
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Affiliation(s)
- Lisa Muniz
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Estelle Nicolas
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Didier Trouche
- MCD, Centre de Biologie Integrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
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34
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Mäkinen JJ, Shin Y, Vieras E, Virta P, Metsä-Ketelä M, Murakami KS, Belogurov GA. The mechanism of the nucleo-sugar selection by multi-subunit RNA polymerases. Nat Commun 2021; 12:796. [PMID: 33542236 PMCID: PMC7862312 DOI: 10.1038/s41467-021-21005-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/06/2021] [Indexed: 01/18/2023] Open
Abstract
RNA polymerases (RNAPs) synthesize RNA from NTPs, whereas DNA polymerases synthesize DNA from 2'dNTPs. DNA polymerases select against NTPs by using steric gates to exclude the 2'OH, but RNAPs have to employ alternative selection strategies. In single-subunit RNAPs, a conserved Tyr residue discriminates against 2'dNTPs, whereas selectivity mechanisms of multi-subunit RNAPs remain hitherto unknown. Here, we show that a conserved Arg residue uses a two-pronged strategy to select against 2'dNTPs in multi-subunit RNAPs. The conserved Arg interacts with the 2'OH group to promote NTP binding, but selectively inhibits incorporation of 2'dNTPs by interacting with their 3'OH group to favor the catalytically-inert 2'-endo conformation of the deoxyribose moiety. This deformative action is an elegant example of an active selection against a substrate that is a substructure of the correct substrate. Our findings provide important insights into the evolutionary origins of biopolymers and the design of selective inhibitors of viral RNAPs.
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Affiliation(s)
- Janne J Mäkinen
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Yeonoh Shin
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Eeva Vieras
- Department of Biochemistry, University of Turku, Turku, Finland
| | - Pasi Virta
- Department of Chemistry, University of Turku, Turku, Finland
| | | | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, The Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
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35
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Kalinina M, Skvortsov D, Kalmykova S, Ivanov T, Dontsova O, Pervouchine D. Multiple competing RNA structures dynamically control alternative splicing in the human ATE1 gene. Nucleic Acids Res 2021; 49:479-490. [PMID: 33330934 PMCID: PMC7797038 DOI: 10.1093/nar/gkaa1208] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/07/2020] [Accepted: 11/28/2020] [Indexed: 11/14/2022] Open
Abstract
The mammalian Ate1 gene encodes an arginyl transferase enzyme with tumor suppressor function that depends on the inclusion of one of the two mutually exclusive exons (MXE), exons 7a and 7b. We report that the molecular mechanism underlying MXE splicing in Ate1 involves five conserved regulatory intronic elements R1-R5, of which R1 and R4 compete for base pairing with R3, while R2 and R5 form an ultra-long-range RNA structure spanning 30 Kb. In minigenes, single and double mutations that disrupt base pairings in R1R3 and R3R4 lead to the loss of MXE splicing, while compensatory triple mutations that restore RNA structure revert splicing to that of the wild type. In the endogenous Ate1 pre-mRNA, blocking the competing base pairings by LNA/DNA mixmers complementary to R3 leads to the loss of MXE splicing, while the disruption of R2R5 interaction changes the ratio of MXE. That is, Ate1 splicing is controlled by two independent, dynamically interacting, and functionally distinct RNA structure modules. Exon 7a becomes more included in response to RNA Pol II slowdown, however it fails to do so when the ultra-long-range R2R5 interaction is disrupted, indicating that exon 7a/7b ratio depends on co-transcriptional RNA folding. In sum, these results demonstrate that splicing is coordinated both in time and in space over very long distances, and that the interaction of these components is mediated by RNA structure.
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Affiliation(s)
- Marina Kalinina
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Dmitry Skvortsov
- Moscow State University, Faculty of Chemistry, Moscow 119991, Russia
| | - Svetlana Kalmykova
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Timofei Ivanov
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
| | - Olga Dontsova
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
- Moscow State University, Faculty of Chemistry, Moscow 119991, Russia
| | - Dmitri D Pervouchine
- Skolkovo Institute of Science and Technology, Center of Life Sciences, Moscow 143026, Russia
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36
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Tadele DS, Robertson J, Crispin R, Herrera MC, Chlubnová M, Piechaczyk L, Ayuda-Durán P, Singh SK, Gedde-Dahl T, Fløisand Y, Skavland J, Wesche J, Gjertsen BT, Enserink JM. A cell competition-based small molecule screen identifies a novel compound that induces dual c-Myc depletion and p53 activation. J Biol Chem 2021; 296:100179. [PMID: 33303632 PMCID: PMC7948465 DOI: 10.1074/jbc.ra120.015285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 11/26/2020] [Accepted: 12/10/2020] [Indexed: 11/08/2022] Open
Abstract
Breakpoint Cluster Region-Abelson kinase (BCR-Abl) is a driver oncogene that causes chronic myeloid leukemia and a subset of acute lymphoid leukemias. Although tyrosine kinase inhibitors provide an effective treatment for these diseases, they generally do not kill leukemic stem cells (LSCs), the cancer-initiating cells that compete with normal hematopoietic stem cells for the bone marrow niche. New strategies to target cancers driven by BCR-Abl are therefore urgently needed. We performed a small molecule screen based on competition between isogenic untransformed cells and BCR-Abl-transformed cells and identified several compounds that selectively impair the fitness of BCR-Abl-transformed cells. Interestingly, systems-level analysis of one of these novel compounds, DJ34, revealed that it induced depletion of c-Myc and activation of p53. DJ34-mediated c-Myc depletion occurred in a wide range of tumor cell types, including lymphoma, lung, glioblastoma, breast cancer, and several forms of leukemia, with primary LSCs being particularly sensitive to DJ34. Further analyses revealed that DJ34 interferes with c-Myc synthesis at the level of transcription, and we provide data showing that DJ34 is a DNA intercalator and topoisomerase II inhibitor. Physiologically, DJ34 induced apoptosis, cell cycle arrest, and cell differentiation. Taken together, we have identified a novel compound that dually targets c-Myc and p53 in a wide variety of cancers, and with particularly strong activity against LSCs.
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Affiliation(s)
- Dagim Shiferaw Tadele
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Joseph Robertson
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Richard Crispin
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Maria C Herrera
- Section for Biochemistry and Molecular Biology, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Markéta Chlubnová
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Laure Piechaczyk
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Pilar Ayuda-Durán
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Sachin Kumar Singh
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | | | - Yngvar Fløisand
- Department of Hematology, Oslo University Hospital, Oslo, Norway
| | - Jørn Skavland
- Precision Oncology Research Group, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Jørgen Wesche
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway
| | - Bjørn-Tore Gjertsen
- Precision Oncology Research Group, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Jorrit M Enserink
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo, Norway.
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37
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Figueroa-Vazquez V, Ko J, Breunig C, Baumann A, Giesen N, Pálfi A, Müller C, Lutz C, Hechler T, Kulke M, Müller-Tidow C, Krämer A, Goldschmidt H, Pahl A, Raab MS. HDP-101, an Anti-BCMA Antibody-Drug Conjugate, Safely Delivers Amanitin to Induce Cell Death in Proliferating and Resting Multiple Myeloma Cells. Mol Cancer Ther 2020; 20:367-378. [PMID: 33298585 DOI: 10.1158/1535-7163.mct-20-0287] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/09/2020] [Accepted: 11/24/2020] [Indexed: 11/16/2022]
Abstract
Despite major treatment advances in recent years, patients with multiple myeloma inevitably relapse. The RNA polymerase II complex has been identified as a promising therapeutic target in both proliferating and dormant cancer cells. Alpha-amanitin, a toxin so far without clinical application due to high liver toxicity, specifically inhibits this complex. Here, we describe the development of HDP-101, an anti-B-cell maturation antigen (BCMA) antibody conjugated with an amanitin derivative. HDP-101 displayed high efficacy against both proliferating and resting myeloma cells in vitro, sparing BCMA-negative cells. In subcutaneous and disseminated murine xenograft models, HDP-101 induced tumor regression at low doses, including durable complete remissions after a single intravenous dose. In cynomolgus monkeys, HDP-101 was well tolerated with a promising therapeutic index. In conclusion, HDP-101 safely and selectively delivers amanitin to myeloma cells and provides a novel therapeutic approach to overcome drug resistance in this disease.
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Affiliation(s)
- Vianihuini Figueroa-Vazquez
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany.,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | - Jonathan Ko
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany.,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Anja Baumann
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany.,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | - Nicola Giesen
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany.,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | - Anikó Pálfi
- Heidelberg Pharma Research GmbH, Ladenburg, Germany
| | | | | | | | | | - Carsten Müller-Tidow
- Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | - Alwin Krämer
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany.,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
| | - Hartmut Goldschmidt
- Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany.,National Center of Tumor Diseases (NCT), Heidelberg, Germany
| | - Andreas Pahl
- Heidelberg Pharma Research GmbH, Ladenburg, Germany.
| | - Marc S Raab
- Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg, Heidelberg, Germany. .,Department of Internal Medicine V, Heidelberg University Hospital, Heidelberg, Germany
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38
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Rymen B, Ferrafiat L, Blevins T. Non-coding RNA polymerases that silence transposable elements and reprogram gene expression in plants. Transcription 2020; 11:172-191. [PMID: 33180661 PMCID: PMC7714444 DOI: 10.1080/21541264.2020.1825906] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Multisubunit RNA polymerase (Pol) complexes are the core machinery for gene expression in eukaryotes. The enzymes Pol I, Pol II and Pol III transcribe distinct subsets of nuclear genes. This family of nuclear RNA polymerases expanded in terrestrial plants by the duplication of Pol II subunit genes. Two Pol II-related enzymes, Pol IV and Pol V, are highly specialized in the production of regulatory, non-coding RNAs. Pol IV and Pol V are the central players of RNA-directed DNA methylation (RdDM), an RNA interference pathway that represses transposable elements (TEs) and selected genes. Genetic and biochemical analyses of Pol IV/V subunits are now revealing how these enzymes evolved from ancestral Pol II to sustain non-coding RNA biogenesis in silent chromatin. Intriguingly, Pol IV-RdDM regulates genes that influence flowering time, reproductive development, stress responses and plant–pathogen interactions. Pol IV target genes vary among closely related taxa, indicating that these regulatory circuits are often species-specific. Data from crops like maize, rice, tomato and Brassicarapa suggest that dynamic repositioning of TEs, accompanied by Pol IV targeting to TE-proximal genes, leads to the reprogramming of plant gene expression over short evolutionary timescales.
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Affiliation(s)
- Bart Rymen
- Institut de biologie moléculaire des plantes, Université de Strasbourg , Strasbourg, France
| | - Laura Ferrafiat
- Institut de biologie moléculaire des plantes, Université de Strasbourg , Strasbourg, France
| | - Todd Blevins
- Institut de biologie moléculaire des plantes, Université de Strasbourg , Strasbourg, France
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39
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Abstract
Gene transcription by RNA polymerase II (Pol II) is the first step in the expression of the eukaryotic genome and a focal point for cellular regulation during development, differentiation, and responses to the environment. Two decades after the determination of the structure of Pol II, the mechanisms of transcription have been elucidated with studies of Pol II complexes with nucleic acids and associated proteins. Here we provide an overview of the nearly 200 available Pol II complex structures and summarize how these structures have elucidated promoter-dependent transcription initiation, promoter-proximal pausing and release of Pol II into active elongation, and the mechanisms that Pol II uses to navigate obstacles such as nucleosomes and DNA lesions. We predict that future studies will focus on how Pol II transcription is interconnected with chromatin transitions, RNA processing, and DNA repair.
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Affiliation(s)
- Sara Osman
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;,
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;,
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40
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Abstract
During transcription elongation at saturating nucleotide concentrations, RNA polymerase (RNAP) performs ∼50 nucleotide-addition cycles every second. The RNAP active center contains a structural element, termed the trigger loop (TL), that has been suggested, but not previously shown, to open to allow a nucleotide to enter and then to close to hold the nucleotide in each nucleotide-addition cycle. Here, using single-molecule fluorescence spectroscopy to monitor distances between a probe incorporated into the TL and a probe incorporated elsewhere in the transcription elongation complex, we show that TL closing and opening occur in solution, define time scales and functional roles of TL closing and opening, and, most crucially, demonstrate that one cycle of TL closing and opening occurs in each nucleotide-addition cycle. The RNA polymerase (RNAP) trigger loop (TL) is a mobile structural element of the RNAP active center that, based on crystal structures, has been proposed to cycle between an “unfolded”/“open” state that allows an NTP substrate to enter the active center and a “folded”/“closed” state that holds the NTP substrate in the active center. Here, by quantifying single-molecule fluorescence resonance energy transfer between a first fluorescent probe in the TL and a second fluorescent probe elsewhere in RNAP or in DNA, we detect and characterize TL closing and opening in solution. We show that the TL closes and opens on the millisecond timescale; we show that TL closing and opening provides a checkpoint for NTP complementarity, NTP ribo/deoxyribo identity, and NTP tri/di/monophosphate identity, and serves as a target for inhibitors; and we show that one cycle of TL closing and opening typically occurs in each nucleotide addition cycle in transcription elongation.
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41
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Structure of complete Pol II-DSIF-PAF-SPT6 transcription complex reveals RTF1 allosteric activation. Nat Struct Mol Biol 2020; 27:668-677. [PMID: 32541898 DOI: 10.1038/s41594-020-0437-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/22/2020] [Indexed: 12/20/2022]
Abstract
Transcription by RNA polymerase II (Pol II) is carried out by an elongation complex. We previously reported an activated porcine Pol II elongation complex, EC*, encompassing the human elongation factors DSIF, PAF1 complex (PAF) and SPT6. Here we report the cryo-EM structure of the complete EC* that contains RTF1, a dissociable PAF subunit critical for chromatin transcription. The RTF1 Plus3 domain associates with Pol II subunit RPB12 and the phosphorylated C-terminal region of DSIF subunit SPT5. RTF1 also forms four α-helices that extend from the Plus3 domain along the Pol II protrusion and RPB10 to the polymerase funnel. The C-terminal 'fastener' helix retains PAF and is followed by a 'latch' that reaches the end of the bridge helix, a flexible element of the Pol II active site. RTF1 strongly stimulates Pol II elongation, and this requires the latch, possibly suggesting that RTF1 activates transcription allosterically by influencing Pol II translocation.
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42
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Qiu C, Jin H, Vvedenskaya I, Llenas JA, Zhao T, Malik I, Visbisky AM, Schwartz SL, Cui P, Čabart P, Han KH, Lai WKM, Metz RP, Johnson CD, Sze SH, Pugh BF, Nickels BE, Kaplan CD. Universal promoter scanning by Pol II during transcription initiation in Saccharomyces cerevisiae. Genome Biol 2020; 21:132. [PMID: 32487207 PMCID: PMC7265651 DOI: 10.1186/s13059-020-02040-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 05/08/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The majority of eukaryotic promoters utilize multiple transcription start sites (TSSs). How multiple TSSs are specified at individual promoters across eukaryotes is not understood for most species. In Saccharomyces cerevisiae, a pre-initiation complex (PIC) comprised of Pol II and conserved general transcription factors (GTFs) assembles and opens DNA upstream of TSSs. Evidence from model promoters indicates that the PIC scans from upstream to downstream to identify TSSs. Prior results suggest that TSS distributions at promoters where scanning occurs shift in a polar fashion upon alteration in Pol II catalytic activity or GTF function. RESULTS To determine the extent of promoter scanning across promoter classes in S. cerevisiae, we perturb Pol II catalytic activity and GTF function and analyze their effects on TSS usage genome-wide. We find that alterations to Pol II, TFIIB, or TFIIF function widely alter the initiation landscape consistent with promoter scanning operating at all yeast promoters, regardless of promoter class. Promoter architecture, however, can determine the extent of promoter sensitivity to altered Pol II activity in ways that are predicted by a scanning model. CONCLUSIONS Our observations coupled with previous data validate key predictions of the scanning model for Pol II initiation in yeast, which we term the shooting gallery. In this model, Pol II catalytic activity and the rate and processivity of Pol II scanning together with promoter sequence determine the distribution of TSSs and their usage.
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Affiliation(s)
- Chenxi Qiu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: Department of Medicine, Division of Translational Therapeutics, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Huiyan Jin
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Irina Vvedenskaya
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jordi Abante Llenas
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843-3128, USA
- Present Address: Whitaker Biomedical Engineering Institute, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Tingting Zhao
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Indranil Malik
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alex M Visbisky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Scott L Schwartz
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Ping Cui
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Pavel Čabart
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Present Address: First Faculty of Medicine, Charles University, BIOCEV, 252 42, Vestec, Czech Republic
| | - Kang Hoo Han
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
| | - William K M Lai
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
- Present Address: Department of Molecular Biology and Genetics, 458 Biotechnology, Cornell University, New York, 14853, USA
| | - Richard P Metz
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Charles D Johnson
- Genomics and Bioinformatics Service, Texas A&M AgriLife, College Station, TX, 77845, USA
| | - Sing-Hoi Sze
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX, 77843-3127, USA
| | - B Franklin Pugh
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, PA, 16802, USA
- Present Address: Department of Molecular Biology and Genetics, 458 Biotechnology, Cornell University, New York, 14853, USA
| | - Bryce E Nickels
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Genetics, Rutgers University, Piscataway, NJ, 08854, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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43
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Therapeutic Targeting of the General RNA Polymerase II Transcription Machinery. Int J Mol Sci 2020; 21:ijms21093354. [PMID: 32397434 PMCID: PMC7246882 DOI: 10.3390/ijms21093354] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/27/2022] Open
Abstract
Inhibitors targeting the general RNA polymerase II (RNAPII) transcription machinery are candidate therapeutics in cancer and other complex diseases. Here, we review the molecular targets and mechanisms of action of these compounds, framing them within the steps of RNAPII transcription. We discuss the effects of transcription inhibitors in vitro and in cellular models (with an emphasis on cancer), as well as their efficacy in preclinical and clinical studies. We also discuss the rationale for inhibiting broadly acting transcriptional regulators or RNAPII itself in complex diseases.
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44
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Lutz C, Simon W, Werner‐Simon S, Pahl A, Müller C. Totalsynthese von α‐ und β‐Amanitin. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Christian Lutz
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Deutschland
| | - Werner Simon
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Deutschland
| | - Susanne Werner‐Simon
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Deutschland
| | - Andreas Pahl
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Deutschland
| | - Christoph Müller
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Deutschland
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45
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Lutz C, Simon W, Werner‐Simon S, Pahl A, Müller C. Total Synthesis of α‐ and β‐Amanitin. Angew Chem Int Ed Engl 2020; 59:11390-11393. [DOI: 10.1002/anie.201914935] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/12/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Christian Lutz
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Germany
| | - Werner Simon
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Germany
| | | | - Andreas Pahl
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Germany
| | - Christoph Müller
- Heidelberg Pharma Research GmbH Department of Chemistry 68529 Ladenburg Germany
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46
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RNA polymerase II stalls on oxidative DNA damage via a torsion-latch mechanism involving lone pair-π and CH-π interactions. Proc Natl Acad Sci U S A 2020; 117:9338-9348. [PMID: 32284409 DOI: 10.1073/pnas.1919904117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Oxidation of guanine generates several types of DNA lesions, such as 8-oxoguanine (8OG), 5-guanidinohydantoin (Gh), and spiroiminodihydantoin (Sp). These guanine-derived oxidative DNA lesions interfere with both replication and transcription. However, the molecular mechanism of transcription processing of Gh and Sp remains unknown. In this study, by combining biochemical and structural analysis, we revealed distinct transcriptional processing of these chemically related oxidized lesions: 8OG allows both error-free and error-prone bypass, whereas Gh or Sp causes strong stalling and only allows slow error-prone incorporation of purines. Our structural studies provide snapshots of how polymerase II (Pol II) is stalled by a nonbulky Gh lesion in a stepwise manner, including the initial lesion encounter, ATP binding, ATP incorporation, jammed translocation, and arrested states. We show that while Gh can form hydrogen bonds with adenosine monophosphate (AMP) during incorporation, this base pair hydrogen bonding is not sufficient to hold an ATP substrate in the addition site and is not stable during Pol II translocation after the chemistry step. Intriguingly, we reveal a unique structural reconfiguration of the Gh lesion in which the hydantoin ring rotates ∼90° and is perpendicular to the upstream base pair planes. The perpendicular hydantoin ring of Gh is stabilized by noncanonical lone pair-π and CH-π interactions, as well as hydrogen bonds. As a result, the Gh lesion, as a functional mimic of a 1,2-intrastrand crosslink, occupies canonical -1 and +1 template positions and compromises the loading of the downstream template base. Furthermore, we suggest Gh and Sp lesions are potential targets of transcription-coupled repair.
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47
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Leng X, Ivanov M, Kindgren P, Malik I, Thieffry A, Brodersen P, Sandelin A, Kaplan CD, Marquardt S. Organismal benefits of transcription speed control at gene boundaries. EMBO Rep 2020; 21:e49315. [PMID: 32103605 PMCID: PMC7132196 DOI: 10.15252/embr.201949315] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/24/2020] [Accepted: 01/30/2020] [Indexed: 12/22/2022] Open
Abstract
RNA polymerase II (RNAPII) transcription is crucial for gene expression. RNAPII density peaks at gene boundaries, associating these key regions for gene expression control with limited RNAPII movement. The connections between RNAPII transcription speed and gene regulation in multicellular organisms are poorly understood. Here, we directly modulate RNAPII transcription speed by point mutations in the second largest subunit of RNAPII in Arabidopsis thaliana. A RNAPII mutation predicted to decelerate transcription is inviable, while accelerating RNAPII transcription confers phenotypes resembling auto-immunity. Nascent transcription profiling revealed that RNAPII complexes with accelerated transcription clear stalling sites at both gene ends, resulting in read-through transcription. The accelerated transcription mutant NRPB2-Y732F exhibits increased association with 5' splice site (5'SS) intermediates and enhanced splicing efficiency. Our findings highlight potential advantages of RNAPII stalling through local reduction in transcription speed to optimize gene expression for the development of multicellular organisms.
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Affiliation(s)
- Xueyuan Leng
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksbergDenmark
| | - Maxim Ivanov
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksbergDenmark
| | - Peter Kindgren
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksbergDenmark
| | - Indranil Malik
- Department of Biochemistry and BiophysicsTexas A&M UniversityCollege StationTXUSA
- Present address:
Department of NeurologyUniversity of Michigan Medical SchoolAnn ArborMIUSA
| | - Axel Thieffry
- Biotech Research and Innovation CentreUniversity of CopenhagenCopenhagenDenmark
- Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Peter Brodersen
- Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Albin Sandelin
- Biotech Research and Innovation CentreUniversity of CopenhagenCopenhagenDenmark
- Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Craig D Kaplan
- Department of Biochemistry and BiophysicsTexas A&M UniversityCollege StationTXUSA
- Department of Biological SciencesUniversity of PittsburghPittsburghPAUSA
| | - Sebastian Marquardt
- Department of Plant and Environmental SciencesCopenhagen Plant Science CentreUniversity of CopenhagenFrederiksbergDenmark
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48
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Abstract
RNA polymerase II (Pol II) transcribes all protein-coding genes and many noncoding RNAs in eukaryotic genomes. Although Pol II is a complex, 12-subunit enzyme, it lacks the ability to initiate transcription and cannot consistently transcribe through long DNA sequences. To execute these essential functions, an array of proteins and protein complexes interact with Pol II to regulate its activity. In this review, we detail the structure and mechanism of over a dozen factors that govern Pol II initiation (e.g., TFIID, TFIIH, and Mediator), pausing, and elongation (e.g., DSIF, NELF, PAF, and P-TEFb). The structural basis for Pol II transcription regulation has advanced rapidly in the past decade, largely due to technological innovations in cryoelectron microscopy. Here, we summarize a wealth of structural and functional data that have enabled a deeper understanding of Pol II transcription mechanisms; we also highlight mechanistic questions that remain unanswered or controversial.
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Affiliation(s)
- Allison C Schier
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, Colorado 80303, USA
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49
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Rodrigues DF, Pires das Neves R, Carvalho ATP, Lourdes Bastos M, Costa VM, Carvalho F. In vitro mechanistic studies on α-amanitin and its putative antidotes. Arch Toxicol 2020; 94:2061-2078. [PMID: 32193566 DOI: 10.1007/s00204-020-02718-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/12/2020] [Indexed: 11/29/2022]
Abstract
α-Amanitin plays a key role in Amanita phalloides intoxications. The liver is a major target of α-amanitin toxicity, and while RNA polymerase II (RNA Pol II) transcription inhibition is a well-acknowledged mechanism of α-amanitin toxicity, other possible toxicological pathways remain to be elucidated. This study aimed to assess the mechanisms of α-amanitin hepatotoxicity in HepG2 cells. The putative protective effects of postulated antidotes were also tested in this cell model and in permeabilized HeLa cells. α-Amanitin (0.1-20 µM) displayed time- and concentration-dependent cytotoxicity, when evaluated through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction and neutral red uptake assays. Additionally, α-amanitin decreased nascent RNA synthesis in a concentration- and time-dependent manner. While α-amanitin did not induce changes in mitochondrial membrane potential, it caused a significant increase in intracellular ATP levels, which was not prevented by incubation with oligomycin, an ATP synthetase inhibitor. Concerning the cell redox status, α-amanitin did not increase reactive species production, but caused a significant increase in total and reduced glutathione, which was abolished by pre-incubation with the inhibitor of gamma-glutamylcysteine synthase, buthionine sulfoximine. None of the tested antidotes [N-acetyl cysteine, silibinin, benzylpenicillin, and polymyxin B (PolB)] conferred any protection against α-amanitin-induced cytotoxicity in HepG2 cells or reversed the inhibition of nascent RNA caused by the toxin in permeabilized HeLa cells. Still, PolB interfered with RNA Pol II activity at high concentrations, though not impacting on α-amanitin observed cytotoxicity. New hepatotoxic mechanisms of α-amanitin were described herein, but the lack of protection observed in clinically used antidotes may reflect the lack of knowledge on their true protection mechanisms and may explain their relatively low clinical efficacy.
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Affiliation(s)
- Daniela Ferreira Rodrigues
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Ricardo Pires das Neves
- UC-Biotech, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3060-197, Cantanhede, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal
| | - Alexandra T P Carvalho
- UC-Biotech, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3060-197, Cantanhede, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal
| | - Maria Lourdes Bastos
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Vera M Costa
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.
| | - Félix Carvalho
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal.
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50
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Ferrafiat L, Pflieger D, Singh J, Thieme M, Böhrer M, Himber C, Gerbaud A, Bucher E, Pikaard CS, Blevins T. The NRPD1 N-terminus contains a Pol IV-specific motif that is critical for genome surveillance in Arabidopsis. Nucleic Acids Res 2019; 47:9037-9052. [PMID: 31372633 PMCID: PMC6753494 DOI: 10.1093/nar/gkz618] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 12/29/2022] Open
Abstract
RNA-guided surveillance systems constrain the activity of transposable elements (TEs) in host genomes. In plants, RNA polymerase IV (Pol IV) transcribes TEs into primary transcripts from which RDR2 synthesizes double-stranded RNA precursors for small interfering RNAs (siRNAs) that guide TE methylation and silencing. How the core subunits of Pol IV, homologs of RNA polymerase II subunits, diverged to support siRNA biogenesis in a TE-rich, repressive chromatin context is not well understood. Here we studied the N-terminus of Pol IV’s largest subunit, NRPD1. Arabidopsis lines harboring missense mutations in this N-terminus produce wild-type (WT) levels of NRPD1, which co-purifies with other Pol IV subunits and RDR2. Our in vitro transcription and genomic analyses reveal that the NRPD1 N-terminus is critical for robust Pol IV-dependent transcription, siRNA production and DNA methylation. However, residual RNA-directed DNA methylation observed in one mutant genotype indicates that Pol IV can operate uncoupled from the high siRNA levels typically observed in WT plants. This mutation disrupts a motif uniquely conserved in Pol IV, crippling the enzyme's ability to inhibit retrotransposon mobilization. We propose that the NRPD1 N-terminus motif evolved to regulate Pol IV function in genome surveillance.
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Affiliation(s)
- Laura Ferrafiat
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
| | - David Pflieger
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
| | - Jasleen Singh
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Michael Thieme
- Botanisches Institut, Universität Basel, CH-4056 Basel, Switzerland
| | - Marcel Böhrer
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
| | - Christophe Himber
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
| | - Aude Gerbaud
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
| | - Etienne Bucher
- Botanisches Institut, Universität Basel, CH-4056 Basel, Switzerland
| | - Craig S Pikaard
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN 47405, USA.,Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Todd Blevins
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, F-67084 Strasbourg, France
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