1
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Chandra SD, Gunasekera S, Noichl BP, Patrick BO, Perrin DM. Synthesis of (2 S,3 R,4 R)-Dihydroxyisoleucine for Use in Amatoxin Synthesis. J Org Chem 2024; 89:12739-12747. [PMID: 39167711 DOI: 10.1021/acs.joc.4c01051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
We report a streamlined synthesis of (2S,3R,4R)-4,5-dihydroxy isoleucine (DHIle), an amino acid found in α-amanitin, which appears to be critical for toxicity. This synthetic route is transition metal-free and enables the production of significant quantities of DHIle with suitable protection for use in peptide synthesis. Its incorporation into a cytotoxic amatoxin analog is reported.
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Affiliation(s)
- Shambhu Deo Chandra
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - Shanal Gunasekera
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - Benjamin Philipp Noichl
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - Brian O Patrick
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
| | - David M Perrin
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1 Canada
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2
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Xu H, Akinyemi IA, Haley J, McIntosh MT, Bhaduri-McIntosh S. ATM, KAP1 and the Epstein-Barr virus polymerase processivity factor direct traffic at the intersection of transcription and replication. Nucleic Acids Res 2023; 51:11104-11122. [PMID: 37852757 PMCID: PMC10639065 DOI: 10.1093/nar/gkad823] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/09/2023] [Accepted: 09/20/2023] [Indexed: 10/20/2023] Open
Abstract
The timing of transcription and replication must be carefully regulated for heavily-transcribed genomes of double-stranded DNA viruses: transcription of immediate early/early genes must decline as replication ramps up from the same genome-ensuring efficient and timely replication of viral genomes followed by their packaging by structural proteins. To understand how the prototypic DNA virus Epstein-Barr virus tackles the logistical challenge of switching from transcription to DNA replication, we examined the proteome at viral replication forks. Specifically, to transition from transcription, the viral DNA polymerase-processivity factor EA-D is SUMOylated by the epigenetic regulator and E3 SUMO-ligase KAP1/TRIM28. KAP1's SUMO2-ligase function is triggered by phosphorylation via the PI3K-related kinase ATM and the RNA polymerase II-associated helicase RECQ5 at the transcription machinery. SUMO2-EA-D then recruits the histone loader CAF1 and the methyltransferase SETDB1 to silence the parental genome via H3K9 methylation, prioritizing replication. Thus, a key viral protein and host DNA repair, epigenetic and transcription-replication interference pathways orchestrate the handover from transcription-to-replication, a fundamental feature of DNA viruses.
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Affiliation(s)
- Huanzhou Xu
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
| | - Ibukun A Akinyemi
- Child Health Research Institute, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
| | - John Haley
- Department of Pathology and Stony Brook Proteomics Center, Stony Brook University, Stony Brook, NY 11794, USA
| | - Michael T McIntosh
- Child Health Research Institute, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Sumita Bhaduri-McIntosh
- Division of Infectious Diseases, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
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3
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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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4
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Steurer B, Janssens RC, Geijer ME, Aprile-Garcia F, Geverts B, Theil AF, Hummel B, van Royen ME, Evers B, Bernards R, Houtsmuller AB, Sawarkar R, Marteijn J. DNA damage-induced transcription stress triggers the genome-wide degradation of promoter-bound Pol II. Nat Commun 2022; 13:3624. [PMID: 35750669 PMCID: PMC9232492 DOI: 10.1038/s41467-022-31329-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 06/10/2022] [Indexed: 01/22/2023] Open
Abstract
The precise regulation of RNA Polymerase II (Pol II) transcription after genotoxic stress is crucial for proper execution of the DNA damage-induced stress response. While stalling of Pol II on transcription-blocking lesions (TBLs) blocks transcript elongation and initiates DNA repair in cis, TBLs additionally elicit a response in trans that regulates transcription genome-wide. Here we uncover that, after an initial elongation block in cis, TBLs trigger the genome-wide VCP-mediated proteasomal degradation of promoter-bound, P-Ser5-modified Pol II in trans. This degradation is mechanistically distinct from processing of TBL-stalled Pol II, is signaled via GSK3, and contributes to the TBL-induced transcription block, even in transcription-coupled repair-deficient cells. Thus, our data reveal the targeted degradation of promoter-bound Pol II as a critical pathway that allows cells to cope with DNA damage-induced transcription stress and enables the genome-wide adaptation of transcription to genotoxic stress.
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Affiliation(s)
- Barbara Steurer
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Roel C Janssens
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marit E Geijer
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - Bart Geverts
- Department of Pathology, Optical Imaging Centre, Erasmus MC, Rotterdam, The Netherlands
| | - Arjan F Theil
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Barbara Hummel
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Martin E van Royen
- Department of Pathology, Optical Imaging Centre, Erasmus MC, Rotterdam, The Netherlands
| | - Bastiaan Evers
- Oncode Institute, Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - René Bernards
- Oncode Institute, Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Adriaan B Houtsmuller
- Department of Pathology, Optical Imaging Centre, Erasmus MC, Rotterdam, The Netherlands
| | - Ritwick Sawarkar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
- MRC, University of Cambridge, Cambridge, UK
| | - Jurgen Marteijn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands.
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5
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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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6
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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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7
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Zhang Z, Li H, Deng Y, Schuck K, Raulefs S, Maeritz N, Yu Y, Hechler T, Pahl A, Fernández-Sáiz V, Wan Y, Wang G, Engleitner T, Öllinger R, Rad R, Reichert M, Diakopoulos KN, Weber V, Li J, Shen S, Zou X, Kleeff J, Mihaljevic A, Michalski CW, Algül H, Friess H, Kong B. AGR2-Dependent Nuclear Import of RNA Polymerase II Constitutes a Specific Target of Pancreatic Ductal Adenocarcinoma in the Context of Wild-Type p53. Gastroenterology 2021; 161:1601-1614.e23. [PMID: 34303658 DOI: 10.1053/j.gastro.2021.07.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 06/25/2021] [Accepted: 07/17/2021] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Promoted by pancreatitis, oncogenic KrasG12D triggers acinar cells' neoplastic transformation through acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia. Anterior gradient 2 (Agr2), a known inhibitor of p53, is detected at early stage of pancreatic ductal adenocarcinoma (PDAC) development. RNA polymerase II (RNAPII) is a key nuclear enzyme; regulation of its nuclear localization in mammalian cells represents a potential therapeutic target. METHODS A mouse model of inflammation-accelerated KrasG12D-driven ADM and pancreatic intraepithelial neoplasia development was used. Pancreas-specific Agr2 ablation was performed to access its role in pancreatic carcinogenesis. Hydrophobic hexapeptides loaded in liposomes were developed to disrupt Agr2-RNAPII complex. RESULTS We found that Agr2 is up-regulated in ADM-to-pancreatic intraepithelial neoplasia transition in inflammation and KrasG12D-driven early pancreatic carcinogenesis. Genetic ablation of Agr2 specifically blocks this metaplastic-to-neoplastic process. Mechanistically, Agr2 directs the nuclear import of RNAPII via its C-terminal nuclear localization signal, undermining the ATR-dependent p53 activation in ADM lesions. Because Agr2 binds to the largest subunit of RNAPII in a peptide motif-dependent manner, we developed a hexapeptide to interfere with the nuclear import of RNAPII by competitively disrupting the Agr2-RNAPII complex. This novel hexapeptide leads to dysfunction of RNAPII with concomitant activation of DNA damage response in early neoplastic lesions; hence, it dramatically compromises PDAC initiation in vivo. Moreover, the hexapeptide sensitizes PDAC cells and patient-derived organoids harboring wild-type p53 to RNAPII inhibitors and first-line chemotherapeutic agents in vivo. Of note, this therapeutic effect is efficient across various cancer types. CONCLUSIONS Agr2 is identified as a novel adaptor protein for nuclear import of RNAPII in mammalian cells. Also, we provide genetic evidence defining Agr2-dependent nuclear import of RNAPII as a pharmaceutically accessible target for prevention and treatment in PDAC in the context of wild-type p53.
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MESH Headings
- Active Transport, Cell Nucleus
- Animals
- Antineoplastic Agents/pharmacology
- Carcinoma in Situ/drug therapy
- Carcinoma in Situ/enzymology
- Carcinoma in Situ/genetics
- Carcinoma in Situ/pathology
- Carcinoma, Pancreatic Ductal/drug therapy
- Carcinoma, Pancreatic Ductal/enzymology
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/pathology
- Cell Transformation, Neoplastic/genetics
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Gene Expression Regulation, Neoplastic
- Metaplasia
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Knockout
- Mice, SCID
- Mucoproteins/genetics
- Mucoproteins/metabolism
- Mutation
- Oligopeptides/pharmacology
- Oncogene Proteins/genetics
- Oncogene Proteins/metabolism
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/enzymology
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/pathology
- Proto-Oncogene Proteins p21(ras)/genetics
- RNA Polymerase II/genetics
- RNA Polymerase II/metabolism
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
- Mice
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Affiliation(s)
- Zhiheng Zhang
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Hongzhen Li
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China; Department of Surgery, Ulm University Hospital, Ulm University, Ulm, Germany
| | - Yibin Deng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, and College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Kathleen Schuck
- Department of Surgery, Ulm University Hospital, Ulm University, Ulm, Germany
| | - Susanne Raulefs
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Nadja Maeritz
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Yuanyuan Yu
- Department of Surgery, Ulm University Hospital, Ulm University, Ulm, Germany
| | | | - Andreas Pahl
- Heidelberg Pharma Research GmbH, Ladenburg, Germany
| | - Vanesa Fernández-Sáiz
- Department of Medicine III, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Center for Translational Cancer Research, Technische Universität München, Munich, Germany
| | - Yuan Wan
- The Pq Laboratory of Micro/Nano BiomeDx, Department of Biomedical Engineering, Binghamton University, State University of New York, Binghamton, New York
| | - Guosheng Wang
- The Pq Laboratory of Micro/Nano BiomeDx, Department of Biomedical Engineering, Binghamton University, State University of New York, Binghamton, New York
| | - Thomas Engleitner
- Center for Translational Cancer Research, Technische Universität München, Munich, Germany; Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; Comprehensive Cancer Center Munich, Technical University of Munich, Munich, Germany
| | - Rupert Öllinger
- Center for Translational Cancer Research, Technische Universität München, Munich, Germany; Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; German Cancer Consortium at the partner site Munich, Munich, Germany
| | - Roland Rad
- Center for Translational Cancer Research, Technische Universität München, Munich, Germany; Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany; German Cancer Consortium at the partner site Munich, Munich, Germany
| | - Maximilian Reichert
- Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | | | - Verena Weber
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Jingjing Li
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China
| | - Shanshan Shen
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China
| | - Xiaoping Zou
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China
| | - Jörg Kleeff
- Department of Visceral, Vascular and Endocrine Surgery, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Andre Mihaljevic
- Department of Surgery, Ulm University Hospital, Ulm University, Ulm, Germany
| | | | - Hana Algül
- Comprehensive Cancer Center Munich, Technical University of Munich, Munich, Germany
| | - Helmut Friess
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Bo Kong
- Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University, Medical School, Nanjing, China; Department of Surgery, Ulm University Hospital, Ulm University, Ulm, Germany.
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8
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Weems JC, Slaughter BD, Unruh JR, Weaver KJ, Miller BD, Delventhal KM, Conaway JW, Conaway RC. A role for the Cockayne Syndrome B (CSB)-Elongin ubiquitin ligase complex in signal-dependent RNA polymerase II transcription. J Biol Chem 2021; 297:100862. [PMID: 34116057 PMCID: PMC8294581 DOI: 10.1016/j.jbc.2021.100862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/27/2021] [Accepted: 06/07/2021] [Indexed: 11/19/2022] Open
Abstract
The Elongin complex was originally identified as an RNA polymerase II (RNAPII) elongation factor and subsequently as the substrate recognition component of a Cullin-RING E3 ubiquitin ligase. More recent evidence indicates that the Elongin ubiquitin ligase assembles with the Cockayne syndrome B helicase (CSB) in response to DNA damage and can target stalled polymerases for ubiquitylation and removal from the genome. In this report, we present evidence that the CSB-Elongin ubiquitin ligase pathway has roles beyond the DNA damage response in the activation of RNAPII-mediated transcription. We observed that assembly of the CSB-Elongin ubiquitin ligase is induced not just by DNA damage, but also by a variety of signals that activate RNAPII-mediated transcription, including endoplasmic reticulum (ER) stress, amino acid starvation, retinoic acid, glucocorticoids, and doxycycline treatment of cells carrying several copies of a doxycycline-inducible reporter. Using glucocorticoid receptor (GR)-regulated genes as a model, we showed that glucocorticoid-induced transcription is accompanied by rapid recruitment of CSB and the Elongin ubiquitin ligase to target genes in a step that depends upon the presence of transcribing RNAPII on those genes. Consistent with the idea that the CSB-Elongin pathway plays a direct role in GR-regulated transcription, mouse cells lacking the Elongin subunit Elongin A exhibit delays in both RNAPII accumulation on and dismissal from target genes following glucocorticoid addition and withdrawal, respectively. Taken together, our findings bring to light a new role for the CSB-Elongin pathway in RNAPII-mediated transcription.
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Affiliation(s)
- Juston C Weems
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | | | - Jay R Unruh
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Kyle J Weaver
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Brandon D Miller
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Kym M Delventhal
- Stowers Institute for Medical Research, Kansas City, Missouri, USA
| | - Joan W Conaway
- Stowers Institute for Medical Research, Kansas City, Missouri, USA; Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA.
| | - Ronald C Conaway
- Stowers Institute for Medical Research, Kansas City, Missouri, USA; Department of Biochemistry & Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas, USA.
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9
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Fry AL, Webster AK, Burnett J, Chitrakar R, Baugh LR, Hubbard EJA. DAF-18/PTEN inhibits germline zygotic gene activation during primordial germ cell quiescence. PLoS Genet 2021; 17:e1009650. [PMID: 34288923 PMCID: PMC8294487 DOI: 10.1371/journal.pgen.1009650] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
Quiescence, an actively-maintained reversible state of cell cycle arrest, is not well understood. PTEN is one of the most frequently lost tumor suppressors in human cancers and regulates quiescence of stem cells and cancer cells. The sole PTEN ortholog in Caenorhabditis elegans is daf-18. In a C. elegans loss-of-function mutant for daf-18, primordial germ cells (PGCs) divide inappropriately in L1 larvae hatched into starvation conditions, in a TOR-dependent manner. Here, we further investigated the role of daf-18 in maintaining PGC quiescence in L1 starvation. We found that maternal or zygotic daf-18 is sufficient to maintain cell cycle quiescence, that daf-18 acts in the germ line and soma, and that daf-18 affects timing of PGC divisions in fed animals. Importantly, our results also implicate daf-18 in repression of germline zygotic gene activation, though not in germline fate specification. However, TOR is less important to germline zygotic gene expression, suggesting that in the absence of food, daf-18/PTEN prevents inappropriate germline zygotic gene activation and cell division by distinct mechanisms.
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Affiliation(s)
- Amanda L. Fry
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Amy K. Webster
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - Julia Burnett
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Rojin Chitrakar
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - L. Ryan Baugh
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - E. Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
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10
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Conserved long-range base pairings are associated with pre-mRNA processing of human genes. Nat Commun 2021; 12:2300. [PMID: 33863890 PMCID: PMC8052449 DOI: 10.1038/s41467-021-22549-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 03/20/2021] [Indexed: 02/07/2023] Open
Abstract
The ability of nucleic acids to form double-stranded structures is essential for all living systems on Earth. Current knowledge on functional RNA structures is focused on locally-occurring base pairs. However, crosslinking and proximity ligation experiments demonstrated that long-range RNA structures are highly abundant. Here, we present the most complete to-date catalog of conserved complementary regions (PCCRs) in human protein-coding genes. PCCRs tend to occur within introns, suppress intervening exons, and obstruct cryptic and inactive splice sites. Double-stranded structure of PCCRs is supported by decreased icSHAPE nucleotide accessibility, high abundance of RNA editing sites, and frequent occurrence of forked eCLIP peaks. Introns with PCCRs show a distinct splicing pattern in response to RNAPII slowdown suggesting that splicing is widely affected by co-transcriptional RNA folding. The enrichment of 3'-ends within PCCRs raises the intriguing hypothesis that coupling between RNA folding and splicing could mediate co-transcriptional suppression of premature pre-mRNA cleavage and polyadenylation.
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11
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Hambira CM, Matinkhoo K, Pryyma A, Patrick BO, Perrin DM. Scaling Amatoxin Synthesis with an Improved Route to (2 S,3 R,4 R)-Dihydroxyisoleucine Exemplified by a Toxic, Clickable α-Amanitin Analogue. J Org Chem 2021; 86:5362-5370. [PMID: 33710901 DOI: 10.1021/acs.joc.0c03022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here we report a scalable synthesis of the key amino acid residue, (2S,3R,4R)-4,5-dihydroxyisoleucine (DHIle) in α-amanitin, that in turn enables the scalable synthesis of an equipotent analogue, Asn(N-ethylazide)-S,6'-dideoxy-α-amanitin, suitable for CuAAC conjugation to empower studies on therapeutic antibody-drug conjugates.
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Affiliation(s)
- Chido M Hambira
- Chemistry Department, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
| | - Kaveh Matinkhoo
- Chemistry Department, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
| | - Alla Pryyma
- Chemistry Department, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
| | - Brian O Patrick
- Chemistry Department, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
| | - David M Perrin
- Chemistry Department, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T1Z1, Canada
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12
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Laham-Karam N, Pinto GP, Poso A, Kokkonen P. Transcription and Translation Inhibitors in Cancer Treatment. Front Chem 2020; 8:276. [PMID: 32373584 PMCID: PMC7186406 DOI: 10.3389/fchem.2020.00276] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 03/20/2020] [Indexed: 12/12/2022] Open
Abstract
Transcription and translation are fundamental cellular processes that govern the protein production of cells. These processes are generally up regulated in cancer cells, to maintain the enhanced metabolism and proliferative state of these cells. As such cancerous cells can be susceptible to transcription and translation inhibitors. There are numerous druggable proteins involved in transcription and translation which make lucrative targets for cancer drug development. In addition to proteins, recent years have shown that the "undruggable" transcription factors and RNA molecules can also be targeted to hamper the transcription or translation in cancer. In this review, we summarize the properties and function of the transcription and translation inhibitors that have been tested and developed, focusing on the advances of the last 5 years. To complement this, we also discuss some of the recent advances in targeting oncogenes tightly controlling transcription including transcription factors and KRAS. In addition to natural and synthetic compounds, we review DNA and RNA based approaches to develop cancer drugs. Finally, we conclude with the outlook to the future of the development of transcription and translation inhibitors.
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Affiliation(s)
- Nihay Laham-Karam
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Gaspar P. Pinto
- International Clinical Research Center, St. Anne University Hospital, Brno, Czechia
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Brno, Czechia
| | - Antti Poso
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
- University Hospital Tübingen, Department of Internal Medicine VIII, University of Tübingen, Tübingen, Germany
| | - Piia Kokkonen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
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13
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Tateishi-Karimata H, Sugimoto N. Chemical biology of non-canonical structures of nucleic acids for therapeutic applications. Chem Commun (Camb) 2020; 56:2379-2390. [PMID: 32022004 DOI: 10.1039/c9cc09771f] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
DNA forms not only the canonical duplex structure but also non-canonical structures. Most potential sequences that induce the formation of non-canonical structures are present in disease-related genes. Interestingly, biological reactions are inhibited or dysregulated by non-canonical structure formation in disease-related genes. To control biological reactions, methods for inducing the formation of non-canonical structures have been developed using small molecules and oligonucleotides. In this feature article, we review biological reactions such as replication, transcription, and reverse transcription controlled by non-canonical DNA structures formed by disease-related genes. Furthermore, we discuss recent studies aimed at developing methods for regulating these biological reactions using drugs targeting the DNA structure.
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Affiliation(s)
- Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, 650-0047, Japan.
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An F-Box Protein, Mdm30, Interacts with TREX Subunit Sub2 To Regulate Cellular Abundance Cotranscriptionally in Orchestrating mRNA Export Independently of Splicing and Mitochondrial Function. Mol Cell Biol 2020; 40:MCB.00570-19. [PMID: 31932480 DOI: 10.1128/mcb.00570-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/03/2020] [Indexed: 02/02/2023] Open
Abstract
Although an F-box protein, Mdm30, is found to regulate ubiquitylation of the Sub2 component of TREX (transcription-export) complex for proteasomal degradation in stimulation of mRNA export, it remains unknown whether such ubiquitin-proteasome system (UPS) regulation of Sub2 occurs cotranscriptionally via its interaction with Mdm30. Further, it is unclear whether impaired UPS regulation of Sub2 in the absence of Mdm30 alters mRNA export via splicing defects of export factors and/or mitochondrial dynamics/function, since Sub2 controls mRNA splicing and Mdm30 regulates mitochondrial aggregation. Here, we show that Mdm30 interacts with Sub2, and temporary shutdown of Mdm30 enhances Sub2's abundance and impairs mRNA export. Likewise, Sub2's abundance is increased following transcriptional inhibition. These results support Mdm30's direct role in regulation of Sub2's cellular abundance in a transcription-dependent manner. Consistently, the chromatin-bound Sub2 level is increased in the absence of Mdm30. Further, we find that Mdm30 does not facilitate splicing of export factors. Moreover, Mdm30 does not have a dramatic effect on mitochondrial respiration/function, and mRNA export occurs in the absence of Fzo1, which is required for mitochondrial dynamics/respiration. Collective results reveal that Mdm30 interacts with Sub2 for proteasomal degradation in a transcription-dependent manner to promote mRNA export independently of splicing or mitochondrial function, thus advancing our understanding of mRNA export.
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15
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Abstract
Approximately 75% of all disease-relevant human proteins, including those involved in intracellular protein-protein interactions (PPIs), are undruggable with the current drug modalities (i.e., small molecules and biologics). Macrocyclic peptides provide a potential solution to these undruggable targets because their larger sizes (relative to conventional small molecules) endow them the capability of binding to flat PPI interfaces with antibody-like affinity and specificity. Powerful combinatorial library technologies have been developed to routinely identify cyclic peptides as potent, specific inhibitors against proteins including PPI targets. However, with the exception of a very small set of sequences, the vast majority of cyclic peptides are impermeable to the cell membrane, preventing their application against intracellular targets. This Review examines common structural features that render most cyclic peptides membrane impermeable, as well as the unique features that allow the minority of sequences to enter the cell interior by passive diffusion, endocytosis/endosomal escape, or other mechanisms. We also present the current state of knowledge about the molecular mechanisms of cell penetration, the various strategies for designing cell-permeable, biologically active cyclic peptides against intracellular targets, and the assay methods available to quantify their cell-permeability.
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Affiliation(s)
- Patrick G. Dougherty
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
| | - Ashweta Sahni
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
| | - Dehua Pei
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12 Avenue, Columbus, Ohio 43210, United States
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16
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Vogt E, Künzler M. Discovery of novel fungal RiPP biosynthetic pathways and their application for the development of peptide therapeutics. Appl Microbiol Biotechnol 2019; 103:5567-5581. [PMID: 31147756 DOI: 10.1007/s00253-019-09893-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/06/2019] [Accepted: 05/06/2019] [Indexed: 12/18/2022]
Abstract
Bioactive peptide natural products are an important source of therapeutics. Prominent examples are the antibiotic penicillin and the immunosuppressant cyclosporine which are both produced by fungi and have revolutionized modern medicine. Peptide biosynthesis can occur either non-ribosomally via large enzymes referred to as non-ribosomal peptide synthetases (NRPS) or ribosomally. Ribosomal peptides are synthesized as part of a larger precursor peptide where they are posttranslationally modified and subsequently proteolytically released. Such peptide natural products are referred to as ribosomally synthesized and posttranslationally modified peptides (RiPPs). Their biosynthetic pathways have recently received a lot of attention, both from a basic and applied research point of view, due to the discoveries of several novel posttranslational modifications of the peptide backbone. Some of these modifications were so far only known from NRPSs and significantly increase the chemical space covered by this class of peptide natural products. Latter feature, in combination with the promiscuity of the modifying enzymes and the genetic encoding of the peptide sequence, makes RiPP biosynthetic pathways attractive for synthetic biology approaches to identify novel peptide therapeutics via screening of de novo generated peptide libraries and, thus, exploit bioactive peptide natural products beyond their direct use as therapeutics. This review focuses on the recent discovery and characterization of novel RiPP biosynthetic pathways in fungi and their possible application for the development of novel peptide therapeutics.
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Affiliation(s)
- Eva Vogt
- ETH Zürich, Department of Biology, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Markus Künzler
- ETH Zürich, Department of Biology, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland.
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17
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Qiu Z, Zhong D, Yang B. Preventive and Therapeutic Effect of Ganoderma (Lingzhi) on Liver Injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1182:217-242. [DOI: 10.1007/978-981-32-9421-9_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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Cho SF, Anderson KC, Tai YT. Targeting B Cell Maturation Antigen (BCMA) in Multiple Myeloma: Potential Uses of BCMA-Based Immunotherapy. Front Immunol 2018; 9:1821. [PMID: 30147690 PMCID: PMC6095983 DOI: 10.3389/fimmu.2018.01821] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/24/2018] [Indexed: 01/10/2023] Open
Abstract
The approval of the first two monoclonal antibodies targeting CD38 (daratumumab) and SLAMF7 (elotuzumab) in late 2015 for treating relapsed and refractory multiple myeloma (RRMM) was a critical advance for immunotherapies for multiple myeloma (MM). Importantly, the outcome of patients continues to improve with the incorporation of this new class of agents with current MM therapies. However, both antigens are also expressed on other normal tissues including hematopoietic lineages and immune effector cells, which may limit their long-term clinical use. B cell maturation antigen (BCMA), a transmembrane glycoprotein in the tumor necrosis factor receptor superfamily 17 (TNFRSF17), is expressed at significantly higher levels in all patient MM cells but not on other normal tissues except normal plasma cells. Importantly, it is an antigen targeted by chimeric antigen receptor (CAR) T-cells, which have already shown significant clinical activities in patients with RRMM who have undergone at least three prior treatments, including a proteasome inhibitor and an immunomodulatory agent. Moreover, the first anti-BCMA antibody–drug conjugate also has achieved significant clinical responses in patients who failed at least three prior lines of therapy, including an anti-CD38 antibody, a proteasome inhibitor, and an immunomodulatory agent. Both BCMA targeting immunotherapies were granted breakthrough status for patients with RRMM by FDA in Nov 2017. Other promising BCMA-based immunotherapeutic macromolecules including bispecific T-cell engagers, bispecific molecules, bispecific or trispecific antibodies, as well as improved forms of next generation CAR T cells, also demonstrate high anti-MM activity in preclinical and even early clinical studies. Here, we focus on the biology of this promising MM target antigen and then highlight preclinical and clinical data of current BCMA-targeted immunotherapies with various mechanisms of action. These crucial studies will enhance selective anti-MM response, transform the treatment paradigm, and extend disease-free survival in MM.
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Affiliation(s)
- Shih-Feng Cho
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States.,Division of Hematology and Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Kenneth C Anderson
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States
| | - Yu-Tzu Tai
- LeBow Institute for Myeloma Therapeutics and Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States
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19
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Live-cell analysis of endogenous GFP-RPB1 uncovers rapid turnover of initiating and promoter-paused RNA Polymerase II. Proc Natl Acad Sci U S A 2018; 115:E4368-E4376. [PMID: 29632207 PMCID: PMC5948963 DOI: 10.1073/pnas.1717920115] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcription by RNA Polymerase II (Pol II) is a highly dynamic process that is tightly regulated at each step of the transcription cycle. We generated GFP-RPB1 knockin cells and developed photobleaching of endogenous Pol II combined with computational modeling to study the in vivo dynamics of Pol II in real time. This approach allowed us to dissect promoter-paused Pol II from initiating and elongating Pol II and showed that initiation and promoter proximal pausing are surprisingly dynamic events, due to premature termination of Pol II. Our study provides new insights into Pol II dynamics and suggests that the iterative release and reinitiation of promoter-bound Pol II is an important component of transcriptional regulation. Initiation and promoter-proximal pausing are key regulatory steps of RNA Polymerase II (Pol II) transcription. To study the in vivo dynamics of endogenous Pol II during these steps, we generated fully functional GFP-RPB1 knockin cells. GFP-RPB1 photobleaching combined with computational modeling revealed four kinetically distinct Pol II fractions and showed that on average 7% of Pol II are freely diffusing, while 10% are chromatin-bound for 2.4 seconds during initiation, and 23% are promoter-paused for only 42 seconds. This unexpectedly high turnover of Pol II at promoters is most likely caused by premature termination of initiating and promoter-paused Pol II and is in sharp contrast to the 23 minutes that elongating Pol II resides on chromatin. Our live-cell–imaging approach provides insights into Pol II dynamics and suggests that the continuous release and reinitiation of promoter-bound Pol II is an important component of transcriptional regulation.
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20
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Grenfell AW, Heald R, Strzelecka M. Mitotic noncoding RNA processing promotes kinetochore and spindle assembly in Xenopus. J Cell Biol 2016; 214:133-41. [PMID: 27402954 PMCID: PMC4949451 DOI: 10.1083/jcb.201604029] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/22/2016] [Indexed: 12/26/2022] Open
Abstract
Grenfell et al. show that transcription and RNA processing occur in metaphase-arrested egg extracts and that noncoding RNA biogenesis is important for centromere, kinetochore, and mitotic spindle assembly. Transcription at the centromere of chromosomes plays an important role in kinetochore assembly in many eukaryotes, and noncoding RNAs contribute to activation of the mitotic kinase Aurora B. However, little is known about how mitotic RNA processing contributes to spindle assembly. We found that inhibition of transcription initiation or RNA splicing, but not translation, leads to spindle defects in Xenopus egg extracts. Spliceosome inhibition resulted in the accumulation of high molecular weight centromeric transcripts, concomitant with decreased recruitment of the centromere and kinetochore proteins CENP-A, CENP-C, and NDC80 to mitotic chromosomes. In addition, blocking transcript synthesis or processing during mitosis caused accumulation of MCAK, a microtubule depolymerase, on the spindle, indicating misregulation of Aurora B. These findings suggest that co-transcriptional recruitment of the RNA processing machinery to nascent mitotic transcripts is an important step in kinetochore and spindle assembly and challenge the idea that RNA processing is globally repressed during mitosis.
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Affiliation(s)
- Andrew W Grenfell
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Magdalena Strzelecka
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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21
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Kaster BC, Knippa KC, Kaplan CD, Peterson DO. RNA Polymerase II Trigger Loop Mobility: INDIRECT EFFECTS OF Rpb9. J Biol Chem 2016; 291:14883-95. [PMID: 27226557 DOI: 10.1074/jbc.m116.714394] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 01/08/2023] Open
Abstract
Rpb9 is a conserved RNA polymerase II (pol II) subunit, the absence of which confers alterations to pol II enzymatic properties and transcription fidelity. It has been suggested previously that Rpb9 affects mobility of the trigger loop (TL), a structural element of Rpb1 that moves in and out of the active site with each elongation cycle. However, a biochemical mechanism for this effect has not been defined. We find that the mushroom toxin α-amanitin, which inhibits TL mobility, suppresses the effect of Rpb9 on NTP misincorporation, consistent with a role for Rpb9 in this process. Furthermore, we have identified missense alleles of RPB9 in yeast that suppress the severe growth defect caused by rpb1-G730D, a substitution within Rpb1 α-helix 21 (α21). These alleles suggest a model in which Rpb9 indirectly affects TL mobility by anchoring the position of α21, with which the TL directly interacts during opening and closing. Amino acid substitutions in Rpb9 or Rpb1 that disrupt proposed anchoring interactions resulted in phenotypes shared by rpb9Δ strains, including increased elongation rate in vitro Combinations of rpb9Δ with the fast rpb1 alleles that we identified did not result in significantly faster in vitro misincorporation rates than those resulting from rpb9Δ alone, and this epistasis is consistent with the idea that defects caused by the rpb1 alleles are related mechanistically to the defects caused by rpb9Δ. We conclude that Rpb9 supports intra-pol II interactions that modulate TL function and thus pol II enzymatic properties.
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Affiliation(s)
- Benjamin C Kaster
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Kevin C Knippa
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Craig D Kaplan
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - David O Peterson
- From the Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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22
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Bacterial Transcription as a Target for Antibacterial Drug Development. Microbiol Mol Biol Rev 2016; 80:139-60. [PMID: 26764017 DOI: 10.1128/mmbr.00055-15] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transcription, the first step of gene expression, is carried out by the enzyme RNA polymerase (RNAP) and is regulated through interaction with a series of protein transcription factors. RNAP and its associated transcription factors are highly conserved across the bacterial domain and represent excellent targets for broad-spectrum antibacterial agent discovery. Despite the numerous antibiotics on the market, there are only two series currently approved that target transcription. The determination of the three-dimensional structures of RNAP and transcription complexes at high resolution over the last 15 years has led to renewed interest in targeting this essential process for antibiotic development by utilizing rational structure-based approaches. In this review, we describe the inhibition of the bacterial transcription process with respect to structural studies of RNAP, highlight recent progress toward the discovery of novel transcription inhibitors, and suggest additional potential antibacterial targets for rational drug design.
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23
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Amanita phalloides poisoning: Mechanisms of toxicity and treatment. Food Chem Toxicol 2015; 86:41-55. [PMID: 26375431 DOI: 10.1016/j.fct.2015.09.008] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 09/08/2015] [Accepted: 09/10/2015] [Indexed: 02/07/2023]
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24
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Čabart P, Jin H, Li L, Kaplan CD. Activation and reactivation of the RNA polymerase II trigger loop for intrinsic RNA cleavage and catalysis. Transcription 2015; 5:e28869. [PMID: 25764335 PMCID: PMC4574878 DOI: 10.4161/trns.28869] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In addition to RNA synthesis, multisubunit RNA polymerases (msRNAPs) support enzymatic reactions such as intrinsic transcript cleavage. msRNAP active sites from different species appear to exhibit differential intrinsic transcript cleavage efficiency and have likely evolved to allow fine-tuning of the transcription process. Here we show that a single amino-acid substitution in the trigger loop (TL) of Saccharomyces RNAP II, Rpb1 H1085Y, engenders a gain of intrinsic cleavage activity where the substituted tyrosine appears to participate in acid-base chemistry at alkaline pH for both intrinsic cleavage and nucleotidyl transfer. We extensively characterize this TL substitution for each of these reactions by examining the responses RNAP II enzymes to catalytic metals, altered pH, and factor inputs. We demonstrate that TFIIF stimulation of the first phosphodiester bond formation by RNAP II requires wild type TL function and that H1085Y substitution within the TL compromises or alters RNAP II responsiveness to both TFIIB and TFIIF. Finally, Mn(2+) stimulation of H1085Y RNAP II reveals possible allosteric effects of TFIIB on the active center and cooperation between TFIIB and TFIIF.
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Affiliation(s)
- Pavel Čabart
- a Department of Biochemistry and Biophysics; Texas A&M University; College Station, TX
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25
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Teasley DC, Parajuli S, Nguyen M, Moore HR, Alspach E, Lock YJ, Honaker Y, Saharia A, Piwnica-Worms H, Stewart SA. Flap Endonuclease 1 Limits Telomere Fragility on the Leading Strand. J Biol Chem 2015; 290:15133-45. [PMID: 25922071 DOI: 10.1074/jbc.m115.647388] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Indexed: 01/01/2023] Open
Abstract
The existence of redundant replication and repair systems that ensure genome stability underscores the importance of faithful DNA replication. Nowhere is this complexity more evident than in challenging DNA templates, including highly repetitive or transcribed sequences. Here, we demonstrate that flap endonuclease 1 (FEN1), a canonical lagging strand DNA replication protein, is required for normal, complete leading strand replication at telomeres. We find that the loss of FEN1 nuclease activity, but not DNA repair activities, results in leading strand-specific telomere fragility. Furthermore, we show that FEN1 depletion-induced telomere fragility is increased by RNA polymerase II inhibition and is rescued by ectopic RNase H1 expression. These data suggest that FEN1 limits leading strand-specific telomere fragility by processing RNA:DNA hybrid/flap intermediates that arise from co-directional collisions occurring between the replisome and RNA polymerase. Our data reveal the first molecular mechanism for leading strand-specific telomere fragility and the first known role for FEN1 in leading strand DNA replication. Because FEN1 mutations have been identified in human cancers, our findings raise the possibility that unresolved RNA:DNA hybrid structures contribute to the genomic instability associated with cancer.
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Affiliation(s)
- Daniel C Teasley
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Shankar Parajuli
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Mai Nguyen
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Hayley R Moore
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Elise Alspach
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110
| | - Ying Jie Lock
- From the Departments of Cell Biology and Physiology and
| | - Yuchi Honaker
- From the Departments of Cell Biology and Physiology and
| | | | | | - Sheila A Stewart
- From the Departments of Cell Biology and Physiology and Integrating Communications within the Cancer Environment Institute, Washington University School of Medicine, Saint Louis, Missouri 63110 Medicine,
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26
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Weems JC, Slaughter BD, Unruh JR, Hall SM, McLaird MB, Gilmore JM, Washburn MP, Florens L, Yasukawa T, Aso T, Conaway JW, Conaway RC. Assembly of the Elongin A Ubiquitin Ligase Is Regulated by Genotoxic and Other Stresses. J Biol Chem 2015; 290:15030-41. [PMID: 25878247 DOI: 10.1074/jbc.m114.632794] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Indexed: 11/06/2022] Open
Abstract
Elongin A performs dual functions in cells as a component of RNA polymerase II (Pol II) transcription elongation factor Elongin and as the substrate recognition subunit of a Cullin-RING E3 ubiquitin ligase that has been shown to target Pol II stalled at sites of DNA damage. Here we investigate the mechanism(s) governing conversion of the Elongin complex from its elongation factor to its ubiquitin ligase form. We report the discovery that assembly of the Elongin A ubiquitin ligase is a tightly regulated process. In unstressed cells, Elongin A is predominately present as part of Pol II elongation factor Elongin. Assembly of Elongin A into the ubiquitin ligase is strongly induced by genotoxic stress; by transcriptional stresses that lead to accumulation of stalled Pol II; and by other stimuli, including endoplasmic reticulum and nutrient stress and retinoic acid signaling, that activate Elongin A-dependent transcription. Taken together, our findings shed new light on mechanisms that control the Elongin A ubiquitin ligase and suggest that it may play a role in Elongin A-dependent transcription.
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Affiliation(s)
- Juston C Weems
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Brian D Slaughter
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Jay R Unruh
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Shawn M Hall
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Merry B McLaird
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Joshua M Gilmore
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Michael P Washburn
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110, the Departments of Pathology and Laboratory Medicine and
| | - Laurence Florens
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110
| | - Takashi Yasukawa
- the Department of Functional Genomics, Kochi Medical School, Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan
| | - Teijiro Aso
- the Department of Functional Genomics, Kochi Medical School, Kohasu, Oko-cho, Nankoku, Kochi 783-8505, Japan
| | - Joan W Conaway
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110, Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
| | - Ronald C Conaway
- From the Stowers Institute for Medical Research, Kansas City, Missouri 64110, Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
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27
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Jordán-Pla A, Gupta I, de Miguel-Jiménez L, Steinmetz LM, Chávez S, Pelechano V, Pérez-Ortín JE. Chromatin-dependent regulation of RNA polymerases II and III activity throughout the transcription cycle. Nucleic Acids Res 2014; 43:787-802. [PMID: 25550430 PMCID: PMC4333398 DOI: 10.1093/nar/gku1349] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The particular behaviour of eukaryotic RNA polymerases along different gene regions and amongst distinct gene functional groups is not totally understood. To cast light onto the alternative active or backtracking states of RNA polymerase II, we have quantitatively mapped active RNA polymerases at a high resolution following a new biotin-based genomic run-on (BioGRO) technique. Compared with conventional profiling with chromatin immunoprecipitation, the analysis of the BioGRO profiles in Saccharomyces cerevisiae shows that RNA polymerase II has unique activity profiles at both gene ends, which are highly dependent on positioned nucleosomes. This is the first demonstration of the in vivo influence of positioned nucleosomes on transcription elongation. The particular features at the 5' end and around the polyadenylation site indicate that this polymerase undergoes extensive specific-activity regulation in the initial and final transcription elongation phases. The genes encoding for ribosomal proteins show distinctive features at both ends. BioGRO also provides the first nascentome analysis for RNA polymerase III, which indicates that transcription of tRNA genes is poorly regulated at the individual copy level. The present study provides a novel perspective of the transcription cycle that incorporates inactivation/reactivation as an important aspect of RNA polymerase dynamics.
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Affiliation(s)
- Antonio Jordán-Pla
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
| | - Ishaan Gupta
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Lola de Miguel-Jiménez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany Stanford University School of Medicine, Department of Genetics, Stanford, CA 94305, USA Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA
| | - Sebastián Chávez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Virgen del Rocío-CSIC-Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, 41013 Seville, Spain
| | - Vicent Pelechano
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - José E Pérez-Ortín
- Departamento de Bioquímica y Biología Molecular and ERI Biotecmed, Facultad de Biológicas, Universitat de València, C/Dr. Moliner 50, E46100 Burjassot, Spain
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28
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Zhou B, Liu W, Zhang H, Wu J, Liu S, Xu H, Wang P. Imaging of nucleolar RNA in living cells using a highly photostable deep-red fluorescent probe. Biosens Bioelectron 2014; 68:189-196. [PMID: 25569876 DOI: 10.1016/j.bios.2014.12.055] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/23/2014] [Accepted: 12/24/2014] [Indexed: 10/24/2022]
Abstract
A new crescent-shape fluorescent probe (named here as CP) that selectively stains RNA in nucleoli of living cells is prepared. CP shows a deep-red emission (658 nm) and a large Stokes shift because of the introduction of rigid-conjugated coumarin moiety into the molecular structure. Cell imaging experiments indicate that CP can rapidly stain nucleoli in living cells by binding with nucleolar RNA, showing performance superior to commercially available nucleoli dye SYTO RNASelect in terms of high photostability and selectivity. More significantly, these excellent properties together with low cytotoxicity enable CP to monitor nucleolar RNA changes during mitosis, and after treating with anti-cancer drugs cisplatin, actinomycin D and α-amanitin. Thus, CP could be a potential tool for real-time, long-term visualization of the dynamic changes for nucleolar RNA and evaluation of the therapeutic effect for anti-cancer drugs that targeted RNA polymerase I (Pol I).
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Affiliation(s)
- Bingjiang Zhou
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Weimin Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hongyan Zhang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiasheng Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Sha Liu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Haitao Xu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Pengfei Wang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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29
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Voss C, Schmitt B, Werner-Simon S, Lutz C, Simon W, Anderl J. A novel, non-radioactive eukaryotic in vitro transcription assay for sensitive quantification of RNA polymerase II activity. BMC Mol Biol 2014; 15:7. [PMID: 24694320 PMCID: PMC4021065 DOI: 10.1186/1471-2199-15-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 03/11/2014] [Indexed: 11/28/2022] Open
Abstract
Background Many studies of the eukaryotic transcription mechanism and its regulation rely on in vitro assays. Conventional RNA polymerase II transcription assays are based on radioactive labelling of the newly synthesized RNA. Due to the inefficient in vitro transcription, the detection of the RNA involving purification and gel electrophoresis is laborious and not always quantitative. Results Herein, we describe a new, non-radioactive, robust and reproducible eukaryotic in vitro transcription assay that has been established in our laboratory. Upon transcription, the newly synthesized RNA is directly detected and quantified using the QuantiGene assay. Alternatively, the RNA can be purified and a primer extension followed by PCR detection or qPCR quantification can be performed. When applied to assess the activity of RNA polymerase II inhibitors, this new method allowed an accurate estimation of their relative potency. Conclusions Our novel assay provides a non-radioactive alternative to a standard in vitro transcription assay that allows for sensitive detection and precise quantification of the newly transcribed, unlabelled RNA and is particularly useful for quantification of strong transcriptional inhibitors like α-amanitin. Moreover, the method can be easily adapted to quantify the reaction yield and the transcription efficiency of other eukaryotic in vitro systems, thus providing a complementary tool for the field of transcriptional research.
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Affiliation(s)
- Cristina Voss
- Department of Biochemistry and Cell Biology, Heidelberg-Pharma GmbH, Schriesheimer Str, 101, Ladenburg D-68526, Germany.
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30
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Tateishi-Karimata H, Isono N, Sugimoto N. New insights into transcription fidelity: thermal stability of non-canonical structures in template DNA regulates transcriptional arrest, pause, and slippage. PLoS One 2014; 9:e90580. [PMID: 24594642 PMCID: PMC3940900 DOI: 10.1371/journal.pone.0090580] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 02/04/2014] [Indexed: 11/25/2022] Open
Abstract
The thermal stability and topology of non-canonical structures of G-quadruplexes and hairpins in template DNA were investigated, and the effect of non-canonical structures on transcription fidelity was evaluated quantitatively. We designed ten template DNAs: A linear sequence that does not have significant higher-order structure, three sequences that form hairpin structures, and six sequences that form G-quadruplex structures with different stabilities. Templates with non-canonical structures induced the production of an arrested, a slipped, and a full-length transcript, whereas the linear sequence produced only a full-length transcript. The efficiency of production for run-off transcripts (full-length and slipped transcripts) from templates that formed the non-canonical structures was lower than that from the linear. G-quadruplex structures were more effective inhibitors of full-length product formation than were hairpin structure even when the stability of the G-quadruplex in an aqueous solution was the same as that of the hairpin. We considered that intra-polymerase conditions may differentially affect the stability of non-canonical structures. The values of transcription efficiencies of run-off or arrest transcripts were correlated with stabilities of non-canonical structures in the intra-polymerase condition mimicked by 20 wt% polyethylene glycol (PEG). Transcriptional arrest was induced when the stability of the G-quadruplex structure (−ΔGo37) in the presence of 20 wt% PEG was more than 8.2 kcal mol−1. Thus, values of stability in the presence of 20 wt% PEG are an important indicator of transcription perturbation. Our results further our understanding of the impact of template structure on the transcription process and may guide logical design of transcription-regulating drugs.
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Affiliation(s)
- Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe, Japan
| | - Noburu Isono
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe, Japan
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe, Japan
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan
- * E-mail:
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31
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Chen Z, Zhang P, Zhang Z. Investigation and analysis of 102 mushroom poisoning cases in Southern China from 1994 to 2012. FUNGAL DIVERS 2013. [DOI: 10.1007/s13225-013-0260-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Freire-Picos MA, Landeira-Ameijeiras V, Mayán MD. Stalled RNAP-II molecules bound to non-coding rDNA spacers are required for normal nucleolus architecture. Yeast 2013; 30:267-77. [PMID: 23703787 DOI: 10.1002/yea.2961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/16/2013] [Accepted: 05/19/2013] [Indexed: 11/10/2022] Open
Abstract
The correct distribution of nuclear domains is critical for the maintenance of normal cellular processes such as transcription and replication, which are regulated depending on their location and surroundings. The most well-characterized nuclear domain, the nucleolus, is essential for cell survival and metabolism. Alterations in nucleolar structure affect nuclear dynamics; however, how the nucleolus and the rest of the nuclear domains are interconnected is largely unknown. In this report, we demonstrate that RNAP-II is vital for the maintenance of the typical crescent-shaped structure of the nucleolar rDNA repeats and rRNA transcription. When stalled RNAP-II molecules are not bound to the chromatin, the nucleolus loses its typical crescent-shaped structure. However, the RNAP-II interaction with Seh1p, or cryptic transcription by RNAP-II, is not critical for morphological changes.
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Affiliation(s)
- M A Freire-Picos
- MRC Clinical Sciences Centre, Imperial College, London, W12 0NN, UK
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33
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Evaluation of micronuclei in mice bone marrow and antioxidant systems in erythrocytes exposed to α-amanitin. Toxicon 2013; 63:147-53. [DOI: 10.1016/j.toxicon.2012.11.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 08/13/2012] [Accepted: 11/29/2012] [Indexed: 01/26/2023]
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34
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Kakihara Y, Houry WA. The R2TP complex: Discovery and functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:101-7. [DOI: 10.1016/j.bbamcr.2011.08.016] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/30/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
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35
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Comparative antidotal efficacy of benzylpenicillin, ceftazidime and rifamycin in cultured human hepatocytes intoxicated with α-amanitin. Arch Toxicol 2011; 83:1091-6. [PMID: 19730819 DOI: 10.1007/s00204-009-0466-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 08/20/2009] [Indexed: 10/20/2022]
Abstract
The most often used antidote to treat poisoning caused by amanitin-containing mushrooms is benzylpenicillin (BPCN). However, a very few reports suggest that other antibiotics such as ceftazidime (CEFT) and rifamycin SV (RIFSV) show better antidote activity against amanitins than BPCN. Given this, there is an ongoing debate as which of three antidotes is optimal for treatment of such poisonings. In this study, the efficacy of BPCN was compared with those of CEFT and RIFSV in human hepatocyte model. The functional integrity and viability of cultured hepatocytes was evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and by measurements of lactic dehydrogenase (LDH) activity. In the first experimental layout, hepatocytes were simultaneously exposed to α-AMA and tested antidotes, while in the second layout, the cells were exposed for the first 12 h to α-AMA only, and then, the medium containing α-AMA was exchanged to culture medium containing both α-AMA and the antidotes tested. The results demonstrated that simultaneous administration of α-AMA and each of tested antidotes (BPCN, CEFT, RIFSV) effectively protected human hepatocytes; however, in the group dosed with BPCN, the highest hepatocyte viability was observed. In cell cultures from experimental layout II, all tested antidotes were ineffective, which indicates that after the critical dose of α-AMA had been taken up by hepatocytes, further suppression of this process does not protect the cells against injury. Thus, 12 h of exposure of incubated hepatocytes to α-AMA is a sufficient time for such a cellular uptake of a critical dose of this toxin. In summary, it can be concluded that easily accessible and low-cost BPCN should be widely used as an antidote against amanitins. However, the key to successful therapy is a quick implementation of an antidote in order to protect as large as possible portion of the liver parenchyma against the devastating uptake of a critical dose of amanitins.
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36
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Boulon S, Pradet-Balade B, Verheggen C, Molle D, Boireau S, Georgieva M, Azzag K, Robert MC, Ahmad Y, Neel H, Lamond AI, Bertrand E. HSP90 and its R2TP/Prefoldin-like cochaperone are involved in the cytoplasmic assembly of RNA polymerase II. Mol Cell 2010; 39:912-924. [PMID: 20864038 DOI: 10.1016/j.molcel.2010.08.023] [Citation(s) in RCA: 216] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 05/12/2010] [Accepted: 06/16/2010] [Indexed: 01/09/2023]
Abstract
RNA polymerases are key multisubunit cellular enzymes. Microscopy studies indicated that RNA polymerase I assembles near its promoter. However, the mechanism by which RNA polymerase II is assembled from its 12 subunits remains unclear. We show here that RNA polymerase II subunits Rpb1 and Rpb3 accumulate in the cytoplasm when assembly is prevented and that nuclear import of Rpb1 requires the presence of all subunits. Using MS-based quantitative proteomics, we characterized assembly intermediates. These included a cytoplasmic complex containing subunits Rpb1 and Rpb8 associated with the HSP90 cochaperone hSpagh (RPAP3) and the R2TP/Prefoldin-like complex. Remarkably, HSP90 activity stabilized incompletely assembled Rpb1 in the cytoplasm. Our data indicate that RNA polymerase II is built in the cytoplasm and reveal quality-control mechanisms that link HSP90 to the nuclear import of fully assembled enzymes. hSpagh also bound the free RPA194 subunit of RNA polymerase I, suggesting a general role in assembling RNA polymerases.
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Affiliation(s)
- Séverine Boulon
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Bérengère Pradet-Balade
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Céline Verheggen
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Dorothée Molle
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Stéphanie Boireau
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Marya Georgieva
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Karim Azzag
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Marie-Cécile Robert
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
| | - Yasmeen Ahmad
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Henry Neel
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France
| | - Angus I Lamond
- Wellcome Trust Centre for Gene Regulation and Expression, University of Dundee, Dundee DD1 5EH, UK
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier - UMR 5535 CNRS, Université Montpellier 2, 34293 Montpellier Cedex 5, France.,Université Montpellier 2, 34095 Montpellier Cedex 5, France.,Université Montpellier 1, 34060 Montpellier Cedex 2, France
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Abstract
Amatoxin poisoning is caused by mushroom species belonging to the genera Amanita, Galerina and Lepiota with the majority of lethal mushroom exposures attributable to Amanita phalloides. High mortality rate in intoxications with these mushrooms is principally a result of the acute liver failure following significant hepatocyte damage due to hepatocellular uptake of amatoxins. A wide variety of amatoxins have been isolated; however, alpha-amanitin (alpha-AMA) appears to be the primary toxin. Studies in vitro and in vivo suggest that alpha-AMA does not only cause hepatocyte necrosis, but also may lead to apoptotic cell death. The objective of this study was to evaluate the complex hepatocyte apoptosis in alpha-AMA cytotoxicity. All experiments were performed on primary cultured canine hepatocytes. The cells were incubated for 12 h with alpha-AMA at a final concentration of 1, 5, 10 and 20 microM. Viability test (MTT assay), apoptosis evaluation (TUNEL reaction, detection of DNA laddering and electron microscopy) were performed at 6 and 12 h of exposure to alpha-AMA. There was a clear correlation between hepatocyte viability, concentration of alpha-AMA and time of exposure to this toxin. The decline in cultured dog hepatocyte viability during the exposure to alpha-AMA is most likely preceded by enhanced cellular apoptosis. Our results demonstrate that apoptosis might contribute to pathogenesis of the severe liver injury in the course of amanitin intoxication, particularly during the early phase of poisoning.
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38
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Magdalan J, Ostrowska A, Piotrowska A, Gomułkiewicz A, Podhorska-Okołów M, Patrzałek D, Szelag A, Dziegiel P. Benzylpenicillin, acetylcysteine and silibinin as antidotes in human hepatocytes intoxicated with alpha-amanitin. ACTA ACUST UNITED AC 2009; 62:367-73. [PMID: 19556115 DOI: 10.1016/j.etp.2009.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 05/14/2009] [Accepted: 05/17/2009] [Indexed: 11/28/2022]
Abstract
Fatalities due to mushroom poisonings are increasing worldwide, with high mortality rate resulting from ingestion of amanitin-producing species. Intoxications caused by amanitin-containing mushrooms represent an unresolved problem in clinical toxicology since no specific and fully efficient antidote is available. The objective of this study was a comparative evaluation of benzylpenicillin (BPCN), acetylcysteine (ACC) and silibinin (SIL) as an antidotes in human hepatocytes intoxicated with alpha-amanitin (alpha-AMA). All experiments were performed on cultured human hepatocytes. Cytotoxicity evaluation of cultured cells using MTT assay and measurement of lactate dehydrogenase (LDH) activity was performed at 12, 24 and 48h of exposure to alpha-AMA and/or antidotes. The significant decline of cell viability and significant increase of LDH activity were observed in all experimental hepatocyte cultures after 12, 24 and 36h exposure to alpha-AMA at concentration 2microM. Exposure of the cells to alpha-AMA resulted also in significant reduction of cell spreading and attachment. However, addition of tested antidotes to experimental cultures significantly stimulated cell proliferation and attachment. In cell cultures exposed simultaneously to alpha-AMA and tested antidotes cytotoxic parameters (MTT and LDH) were not significantly different from control incidences. The cytoprotective effect of all antidotes was not dose-related, which reflects a high efficacy of all these substances. Administration of studied antidotes was not associated with any adverse effects in hepatocytes. The administration of ACC, BPCN or SIL to human hepatocyte cultures showed a similar strong protective effect against cell damage in alpha-AMA toxicity.
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Affiliation(s)
- Jan Magdalan
- Department of Pharmacology, Wrocław Medical University, Wrocław, Poland
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39
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Kireeva M, Nedialkov YA, Gong XQ, Zhang C, Xiong Y, Moon W, Burton ZF, Kashlev M. Millisecond phase kinetic analysis of elongation catalyzed by human, yeast, and Escherichia coli RNA polymerase. Methods 2009; 48:333-45. [PMID: 19398005 DOI: 10.1016/j.ymeth.2009.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 04/05/2009] [Accepted: 04/06/2009] [Indexed: 11/16/2022] Open
Abstract
Strategies for assembly and analysis of human, yeast, and bacterial RNA polymerase elongation complexes are described, and methods are shown for millisecond phase kinetic analyses of elongation using rapid chemical quench flow. Human, yeast, and bacterial RNA polymerases function very similarly in NTP-Mg2+ commitment and phosphodiester bond formation. A "running start, two-bond, double-quench" protocol is described and its advantages discussed. These studies provide information about stable NTP-Mg2+ loading, phosphodiester bond synthesis, the processive transition between bonds, and sequence-specific effects on transcription elongation dynamics.
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Affiliation(s)
- Maria Kireeva
- Gene Regulation and Chromosome Biology Laboratory, National Cancer Institute-Frederick, Bldg. 539, Room 222, Frederick, MD 21702-1201, USA
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Magdalan J, Ostrowska A, Podhorska-Okołów M, Piotrowska A, Iżykowska I, Nowak M, Dolińska-Krajewska B, Zabel M, Szeląg A, Dzięgiel P. Early morphological and functional alterations in canine hepatocytes due to α-amanitin, a major toxin of Amanita phalloides. Arch Toxicol 2008; 83:55-60. [DOI: 10.1007/s00204-008-0376-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 10/14/2008] [Indexed: 11/29/2022]
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Isolation of a Drosophila amplification origin developmentally activated by transcription. Proc Natl Acad Sci U S A 2008; 105:9651-6. [PMID: 18621687 DOI: 10.1073/pnas.0804146105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We exploited the Drosophila Amplicon in Follicle Cells, DAFC-62D, to identify a new metazoan amplification origin, ori62. In addition to the origin, DAFC-62D contains two other developmental stage-specific binding regions for the Origin Recognition Complex (ORC) and the replicative helicase MCM2-7. All three of these regions are required for proper amplification. There are two rounds of amplification initiation at ori62, and the second round is preceded by transcription across ori62. We show by alpha-amanitin inhibition that RNA polymerase II (RNAPII) transcription is required to localize MCM2-7 (but not ORC) to permit the second round of origin firing. This role for transcription appears unique to DAFC-62D, because neither other DAFCs nor ectopic transposons with the DAFC-62D replication elements bounded by functional chromatin insulators are affected by alpha-amanitin. By sequential chromatin immunoprecipitation, we show that the MCM complex and RNAPII are bound to the same 100-500 bp pieces of chromatin during late origin firing. These results raise the possibility that RNAPII may recruit MCM2-7 at some metazoan replication origins.
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Kaplan CD, Larsson KM, Kornberg RD. The RNA polymerase II trigger loop functions in substrate selection and is directly targeted by alpha-amanitin. Mol Cell 2008; 30:547-56. [PMID: 18538653 DOI: 10.1016/j.molcel.2008.04.023] [Citation(s) in RCA: 211] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 03/07/2008] [Accepted: 04/14/2008] [Indexed: 10/22/2022]
Abstract
Structural, biochemical, and genetic studies have led to proposals that a mobile element of multisubunit RNA polymerases, the Trigger Loop (TL), plays a critical role in catalysis and can be targeted by antibiotic inhibitors. Here we present evidence that the Saccharomyces cerevisiae RNA Polymerase II (Pol II) TL participates in substrate selection. Amino acid substitutions within the Pol II TL preferentially alter substrate usage and enzyme fidelity, as does inhibition of transcription by alpha-amanitin. Finally, substitution of His1085 in the TL specifically renders Pol II highly resistant to alpha-amanitin, indicating a functional interaction between His1085 and alpha-amanitin that is supported by rerefinement of an alpha-amanitin-Pol II crystal structure. We propose that alpha-amanitin-inhibited Pol II elongation, which is slow and exhibits reduced substrate selectivity, results from direct alpha-amanitin interference with the TL.
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Affiliation(s)
- Craig D Kaplan
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA.
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43
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Brueckner F, Cramer P. Structural basis of transcription inhibition by alpha-amanitin and implications for RNA polymerase II translocation. Nat Struct Mol Biol 2008; 15:811-8. [PMID: 18552824 DOI: 10.1038/nsmb.1458] [Citation(s) in RCA: 197] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 06/05/2008] [Indexed: 12/28/2022]
Abstract
To study how RNA polymerase II translocates after nucleotide incorporation, we prepared elongation complex crystals in which pre- and post-translocation states interconvert. Crystal soaking with the inhibitor alpha-amanitin locked the elongation complex in a new state, which was refined at 3.4-A resolution and identified as a possible translocation intermediate. The DNA base entering the active site occupies a 'pretemplating' position above the central bridge helix, which is shifted and occludes the templating position. A leucine residue in the trigger loop forms a wedge at the shifted bridge helix, but moves by 13 A to close the active site during nucleotide incorporation. Our results support a Brownian ratchet mechanism that involves swinging of the trigger loop between open, wedged and closed positions, and suggest that alpha-amanitin impairs nucleotide incorporation and translocation by trapping the trigger loop and bridge helix.
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Affiliation(s)
- Florian Brueckner
- Gene Center and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
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44
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Balakrishnan L, Milavetz B. Histone hyperacetylation during SV40 transcription is regulated by p300 and RNA polymerase II translocation. J Mol Biol 2007; 371:1022-37. [PMID: 17658552 PMCID: PMC1987373 DOI: 10.1016/j.jmb.2007.06.080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 06/17/2007] [Accepted: 06/25/2007] [Indexed: 01/03/2023]
Abstract
The effects of the RNA polymerase II (RNAPII) translocation inhibitors alpha amanitin and 5,6-dichloro-1-beta-D-ribobenzimidazole (DRB) and an siRNA targeting p300 on the presence of RNAPII, p300, hyperacetylated H4 and H3 and unmodified H4 and H3 in transcribing simian virus 40 (SV40) minichromosomes were determined. Following treatment with alpha amanitin we observed a profound reduction in the occupancy of the promoter by RNAPII, the loss of p300 from chromatin fragments containing RNAPII, and an increase in the amount of unmodified H4 and H3 associated with the RNAPII. Treatment with DRB had little effect on the presence of RNAPII or p300 but also resulted in a significant increase in the amount of unmodified H4 and H3 present in chromatin fragments associated with RNAPII. Following treatment with a p300 small interfering RNA (siRNA), we observed a significant decrease in late transcription and a corresponding reduction in the amounts of p300 and hyperacetylated histones associated with the transcribing SV40 minichromosomes. We conclude that in transcribing SV40 minichromosomes histone hyperacetylation and deacetylation is dependent upon the presence of p300 and an as yet unknown histone deacetylase associated with the RNAPII complex that occurs coordinately as the RNAPII complex moves through a nucleosome.
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Affiliation(s)
- Lata Balakrishnan
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, ND 58203, USA
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45
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Radhakrishnan SK, Gartel AL. A novel transcriptional inhibitor induces apoptosis in tumor cells and exhibits antiangiogenic activity. Cancer Res 2006; 66:3264-70. [PMID: 16540679 DOI: 10.1158/0008-5472.can-05-3940] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Using a high-throughput cell-based assay, we identified a nucleoside analogue 4-amino-6-hydrazino-7-beta-D-ribofuranosyl-7H-pyrrolo(2,3-d)-pyrimidine-5-carboxamide (ARC), which has the properties of a general transcriptional inhibitor. Specifically, ARC inhibits the phosphorylation of RNA polymerase II by positive transcription elongation factor-b, leading to a block in transcriptional elongation. ARC was able to potently repress p53 targets p21 and hdm2 (human homologue of mdm2) protein levels, but dramatically increased p53 levels similar to other transcriptional inhibitors, including flavopiridol. This increase in p53 corresponded to the down-regulation of short-lived protein hdm2, which is a well-established negative regulator of p53. Remarkably, ARC induced potent apoptosis in human tumor and transformed, but not in normal cells, and possessed strong antiangiogenic activity in vitro. Although ARC promoted the accumulation of p53, ARC-induced apoptosis in tumor cells was p53-independent, suggesting that it may be useful for the treatment of tumors with functionally inactive p53. Furthermore, cell death induced by ARC had a strong correlation with down-regulation of the antiapoptotic gene survivin, which is often overexpressed in human tumors. Taken together, our data suggests that ARC may be an attractive candidate for anticancer drug development.
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46
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Ghosh M, Liu G, Randall G, Bevington J, Leffak M. Transcription factor binding and induced transcription alter chromosomal c-myc replicator activity. Mol Cell Biol 2005; 24:10193-207. [PMID: 15542830 PMCID: PMC529035 DOI: 10.1128/mcb.24.23.10193-10207.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The observation that transcriptionally active genes generally replicate early in S phase and observations of the interaction between transcription factors and replication proteins support the thesis that promoter elements may have a role in DNA replication. To test the relationship between transcription and replication we constructed HeLa cell lines in which inducible green fluorescent protein (GFP)-encoding genes replaced the proximal approximately 820-bp promoter region of the c-myc gene. Without the presence of an inducer, basal expression occurred from the GFP gene in either orientation and origin activity was restored to the mutant c-myc replicator. In contrast, replication initiation was repressed upon induction of transcription. When basal or induced transcription complexes were slowed by the presence of alpha-amanitin, origin activity depended on the orientation of the transcription unit. To test mechanistically whether basal transcription or transcription factor binding was sufficient for replication rescue by the uninduced GFP genes, a GAL4p binding cassette was used to replace all regulatory sequences within approximately 1,400 bp 5' to the c-myc gene. In these cells, expression of a CREB-GAL4 fusion protein restored replication origin activity. These results suggest that transcription factor binding can enhance replication origin activity and that high levels of expression or the persistence of transcription complexes can repress it.
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Affiliation(s)
- M Ghosh
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA
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47
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Gong XQ, Nedialkov YA, Burton ZF. Alpha-amanitin blocks translocation by human RNA polymerase II. J Biol Chem 2004; 279:27422-7. [PMID: 15096519 DOI: 10.1074/jbc.m402163200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our laboratory has developed methods for transient state kinetic analysis of human RNA polymerase II elongation. In these studies, multiple conformations of the RNA polymerase II elongation complex were revealed by their distinct elongation potential and differing dependence on nucleoside triphosphate substrate. Among these are conformations that appear to correspond to different translocation states of the DNA template and RNA-DNA hybrid. Using alpha-amanitin as a dynamic probe of the RNA polymerase II mechanism, we show that the most highly poised conformation of the elongation complex, which we interpreted previously as the posttranslocated state, is selectively resistant to inhibition with alpha-amanitin. Because initially resistant elongation complexes form only a single phosphodiester bond before being rendered inactive in the following bond addition cycle, alpha-amanitin inhibits elongation at each translocation step.
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Affiliation(s)
- Xue Q Gong
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA
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48
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Jiang C, Ito M, Piening V, Bruck K, Roeder RG, Xiao H. TIP30 interacts with an estrogen receptor alpha-interacting coactivator CIA and regulates c-myc transcription. J Biol Chem 2004; 279:27781-9. [PMID: 15073177 DOI: 10.1074/jbc.m401809200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deregulation of c-myc expression is implicated in the pathogenesis of many neoplasias. Estrogen receptor alpha (ERalpha) can increase the rate of c-myc transcription through the recruitment of a variety of cofactors to the promoter, yet the precise roles of these cofactors in transcription and tumorigenesis are largely unknown. We show here that a putative tumor suppressor TIP30, also called CC3 or Htatip2, interacts with an ERalpha-interacting coactivator CIA. Using chromatin immunoprecipitation assays, we demonstrate that TIP30 and CIA are distinct cofactors that are dynamically associated with the promoter and downstream regions of the c-myc gene in response to estrogen. Both TIP30 and CIA are recruited to the c-myc gene promoter by liganded ERalpha in the second transcription cycle. TIP30 overexpression represses ERalpha-mediated c-myc transcription, whereas TIP30 deficiency enhances c-myc transcription in both the absence and presence of estrogen. Ectopic CIA cooperates with TIP30 to repress ERalpha-mediated c-myc transcription. Moreover, virgin TIP30 knockout mice exhibit increased c-myc expression in mammary glands. Together, these results reveal an important role for TIP30 in the regulation of ERalpha-mediated c-myc transcription and suggest a mechanism for tumorigenesis promoted by TIP30 deficiency.
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Affiliation(s)
- Chao Jiang
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha 68198-7696, USA
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Hawryluk PJ, Ujvári A, Luse DS. Characterization of a novel RNA polymerase II arrest site which lacks a weak 3' RNA-DNA hybrid. Nucleic Acids Res 2004; 32:1904-16. [PMID: 15047857 PMCID: PMC390359 DOI: 10.1093/nar/gkh505] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transcript elongation by RNA polymerase II is blocked at DNA sequences called arrest sites. An exceptionally weak RNA-DNA hybrid is often thought to be necessary at the point of arrest. We have identified an arrest site from the tyrosine hydroxylase (TH) gene which does not fit this pattern. Transcription of many sequence variants of this site shows that the RNA-DNA hybrid over the three bases immediately preceding the major arrest point may be strong (i.e. C:G) without interfering with arrest. However, arrest at the TH site requires the presence of a pyrimidine at the 3' end and arrest increases when the 3'-most segment is pyrimidine rich. We also demonstrated that arrest at the TH site is completely dependent on the presence of a purine-rich element immediately upstream of the RNA-DNA hybrid. Thus, the RNA polymerase II arrest element from the TH gene has several unanticipated characteristics: arrest is independent of a weak RNA-DNA hybrid at the 3' end of the transcript, but it requires both a pyrimidine at the 3' end and a polypurine element upstream of the RNA-DNA hybrid.
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Affiliation(s)
- Peter J Hawryluk
- Department of Molecular Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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50
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Kettenberger H, Armache KJ, Cramer P. Architecture of the RNA polymerase II-TFIIS complex and implications for mRNA cleavage. Cell 2003; 114:347-57. [PMID: 12914699 DOI: 10.1016/s0092-8674(03)00598-1] [Citation(s) in RCA: 273] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The transcription elongation factor TFIIS induces mRNA cleavage by enhancing the intrinsic nuclease activity of RNA polymerase (Pol) II. We have diffused TFIIS into Pol II crystals and derived a model of the Pol II-TFIIS complex from X-ray diffraction data to 3.8 A resolution. TFIIS extends from the polymerase surface via a pore to the internal active site, spanning a distance of 100 A. Two essential and invariant acidic residues in a TFIIS loop complement the Pol II active site and could position a metal ion and a water molecule for hydrolytic RNA cleavage. TFIIS also induces extensive structural changes in Pol II that would realign nucleic acids in the active center. Our results support the idea that Pol II contains a single tunable active site for RNA polymerization and cleavage, in contrast to DNA polymerases with two separate active sites for DNA polymerization and cleavage.
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Affiliation(s)
- Hubert Kettenberger
- Institute of Biochemistry, Gene Center, University of Munich, Feodor-Lynen-Str. 25, 81377 Munich, Germany
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