1
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Yuan L, Jiang X, Jia G, Li Z, Wang M, Hu S, Yang J, Liang F, Zhang F, Gao L, Gao N. Minnelide exhibits antileukemic activity by targeting the Ars2/miR-190a-3p axis. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 130:155724. [PMID: 38759317 DOI: 10.1016/j.phymed.2024.155724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 04/25/2024] [Accepted: 05/07/2024] [Indexed: 05/19/2024]
Abstract
BACKGROUND The identification of a novel and effective strategy for the clinical treatment of acute leukemia (AL) is a long-term goal. Minnelide, a water-soluble prodrug of triptolide, has recently been evaluated in phase I and II clinical trials in patients with multiple cancers and has shown promise as an antileukemic agent. However, the molecular mechanism underlying minnelide's antileukemic activity remains unclear. PURPOSE To explore the molecular mechanisms by which minnelide exhibits antileukemic activity. METHODS AL cells, primary human leukemia cells, and a xenograft mouse model were treated with triptolide and minnelide. The molecular mechanism was elucidated using western blotting, immunoprecipitation, flow cytometry, GSEA and liquid chromatography-mass spectrometry analysis. RESULTS Minnelide was highly effective in inhibiting leukemogenesis and improving survival in two complementary AL mouse models. Triptolide, an active form of minnelide, causes cell cycle arrest in G1 phase and induces apoptosis in both human AL cell lines and primary AL cells. Mechanistically, we identified Ars2 as a new chemotherapeutic target of minnelide for AL treatment. We found that triptolide directly targeted Ars2, resulting in the downregulation of miR-190a-3p, which led to the disturbance of PTEN/Akt signaling and culminated in G1 cell cycle arrest and apoptosis. CONCLUSIONS Our findings demonstrate that targeting Ars2/miR-190a-3p signaling using minnelide could represent a novel chemotherapeutic strategy for AL treatment and support the evaluation of minnelide for the treatment of AL in clinical trials.
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Affiliation(s)
- Liang Yuan
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Xiuxing Jiang
- College of Pharmacy, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Guanfei Jia
- College of Pharmacy, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Zhiqiang Li
- College of Pharmacy, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Mei Wang
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Siyi Hu
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Jiawang Yang
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Feng Liang
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Fenglin Zhang
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China
| | - Lu Gao
- Department of Hematology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563000, PR China.
| | - Ning Gao
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, PR China.
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2
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Dubiez E, Pellegrini E, Finderup Brask M, Garland W, Foucher AE, Huard K, Heick Jensen T, Cusack S, Kadlec J. Structural basis for competitive binding of productive and degradative co-transcriptional effectors to the nuclear cap-binding complex. Cell Rep 2024; 43:113639. [PMID: 38175753 DOI: 10.1016/j.celrep.2023.113639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/07/2023] [Accepted: 12/15/2023] [Indexed: 01/06/2024] Open
Abstract
The nuclear cap-binding complex (CBC) coordinates co-transcriptional maturation, transport, or degradation of nascent RNA polymerase II (Pol II) transcripts. CBC with its partner ARS2 forms mutually exclusive complexes with diverse "effectors" that promote either productive or destructive outcomes. Combining AlphaFold predictions with structural and biochemical validation, we show how effectors NCBP3, NELF-E, ARS2, PHAX, and ZC3H18 form competing binary complexes with CBC and how PHAX, NCBP3, ZC3H18, and other effectors compete for binding to ARS2. In ternary CBC-ARS2 complexes with PHAX, NCBP3, or ZC3H18, ARS2 is responsible for the initial effector recruitment but inhibits their direct binding to the CBC. We show that in vivo ZC3H18 binding to both CBC and ARS2 is required for nuclear RNA degradation. We propose that recruitment of PHAX to CBC-ARS2 can lead, with appropriate cues, to competitive displacement of ARS2 and ZC3H18 from the CBC, thus promoting a productive rather than a degradative RNA fate.
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Affiliation(s)
- Etienne Dubiez
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France; Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Erika Pellegrini
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Maja Finderup Brask
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | | | - Karine Huard
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Stephen Cusack
- European Molecular Biology Laboratory, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble Cedex 9, France.
| | - Jan Kadlec
- Univ. Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France.
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3
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Polák P, Garland W, Rathore O, Schmid M, Salerno-Kochan A, Jakobsen L, Gockert M, Gerlach P, Silla T, Andersen JS, Conti E, Jensen TH. Dual agonistic and antagonistic roles of ZC3H18 provide for co-activation of distinct nuclear RNA decay pathways. Cell Rep 2023; 42:113325. [PMID: 37889751 PMCID: PMC10720265 DOI: 10.1016/j.celrep.2023.113325] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/19/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
The RNA exosome is a versatile ribonuclease. In the nucleoplasm of mammalian cells, it is assisted by its adaptors the nuclear exosome targeting (NEXT) complex and the poly(A) exosome targeting (PAXT) connection. Via its association with the ARS2 and ZC3H18 proteins, NEXT/exosome is recruited to capped and short unadenylated transcripts. Conversely, PAXT/exosome is considered to target longer and adenylated substrates via their poly(A) tails. Here, mutational analysis of the core PAXT component ZFC3H1 uncovers a separate branch of the PAXT pathway, which targets short adenylated RNAs and relies on a direct ARS2-ZFC3H1 interaction. We further demonstrate that similar acidic-rich short linear motifs of ZFC3H1 and ZC3H18 compete for a common ARS2 epitope. Consequently, while promoting NEXT function, ZC3H18 antagonizes PAXT activity. We suggest that this organization of RNA decay complexes provides co-activation of NEXT and PAXT at loci with abundant production of short exosome substrates.
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Affiliation(s)
- Patrik Polák
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Om Rathore
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried/Munich, Germany
| | - Lis Jakobsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M, Denmark
| | - Maria Gockert
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Piotr Gerlach
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried/Munich, Germany
| | - Toomas Silla
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried/Munich, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark.
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4
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Rouvière JO, Salerno-Kochan A, Lykke-Andersen S, Garland W, Dou Y, Rathore O, Molska EŠ, Wu G, Schmid M, Bugai A, Jakobsen L, Žumer K, Cramer P, Andersen JS, Conti E, Jensen TH. ARS2 instructs early transcription termination-coupled RNA decay by recruiting ZC3H4 to nascent transcripts. Mol Cell 2023:S1097-2765(23)00384-2. [PMID: 37329882 DOI: 10.1016/j.molcel.2023.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/29/2023] [Accepted: 05/18/2023] [Indexed: 06/19/2023]
Abstract
The RNA-binding ARS2 protein is centrally involved in both early RNA polymerase II (RNAPII) transcription termination and transcript decay. Despite its essential nature, the mechanisms by which ARS2 enacts these functions have remained unclear. Here, we show that a conserved basic domain of ARS2 binds a corresponding acidic-rich, short linear motif (SLiM) in the transcription restriction factor ZC3H4. This interaction recruits ZC3H4 to chromatin to elicit RNAPII termination, independent of other early termination pathways defined by the cleavage and polyadenylation (CPA) and Integrator (INT) complexes. We find that ZC3H4, in turn, forms a direct connection to the nuclear exosome targeting (NEXT) complex, hereby facilitating rapid degradation of the nascent RNA. Hence, ARS2 instructs the coupled transcription termination and degradation of the transcript onto which it is bound. This contrasts with ARS2 function at CPA-instructed termination sites where the protein exclusively partakes in RNA suppression via post-transcriptional decay.
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Affiliation(s)
- Jérôme O Rouvière
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Søren Lykke-Andersen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - William Garland
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Yuhui Dou
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Om Rathore
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Ewa Šmidová Molska
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Guifen Wu
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Andrii Bugai
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark
| | - Lis Jakobsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Kristina Žumer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Munich, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Universitetsbyen 81, Aarhus University, Aarhus, Denmark.
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5
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Yuan L, Jiang X, Gong Q, Gao N. Arsenic resistance protein 2 and microRNA biogenesis: Biological implications in cancer development. Pharmacol Ther 2023; 244:108386. [PMID: 36933704 DOI: 10.1016/j.pharmthera.2023.108386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 03/12/2023] [Accepted: 03/15/2023] [Indexed: 03/18/2023]
Abstract
Arsenic resistance protein 2 (Ars2) is a nuclear protein that plays a critical role in the regulation of microRNA (miRNA) biogenesis. Ars2 is required for cell proliferation and for the early stages of mammalian development through a possible effect on miRNA processing. Increasing evidence reveal that Ars2 is highly expressed in proliferating cancer cells, suggesting that Ars2 may be a potential therapeutic target for cancer. Therefore, development of the novel Ars2 inhibitors could represent the novel therapeutic strategies for treatment of cancer. In this review, we briefly discuss the mechanisms by which Ars2 regulates miRNA biogenesis and its impact on cell proliferation and cancer development. Particularly, we mainly discuss the role of Ars2 in the regulation of cancer development and highlight pharmacological targeting of Ars2 as a promising cancer therapeutic strategy.
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Affiliation(s)
- Liang Yuan
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, China
| | - Xiuxing Jiang
- College of Pharmacy, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, China
| | - Qihai Gong
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, China.
| | - Ning Gao
- Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou 563006, China.
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6
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Mesa-Perez M, Hamilton PT, Miranda A, Brodie N, O’Sullivan C, Christie J, Ryan B, Chow R, Goodlett D, Nelson C, Howard P. OUP accepted manuscript. Nucleic Acids Res 2022; 50:1620-1638. [PMID: 35104878 PMCID: PMC8860587 DOI: 10.1093/nar/gkac033] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/29/2021] [Accepted: 01/13/2022] [Indexed: 12/03/2022] Open
Abstract
The life of RNA polymerase II (RNAPII) transcripts is shaped by the dynamic formation of mutually exclusive ribonucleoprotein complexes (RNPs) that direct transcript biogenesis and turnover. A key regulator of RNA metabolism in the nucleus is the scaffold protein ARS2 (arsenic resistance protein 2), bound to the cap binding complex (CBC). We report here that alternative splicing of ARS2′s intron 5, generates cytoplasmic isoforms that lack 270 amino acids from the N-terminal of the protein and are functionally distinct from nuclear ARS2. Switching of ARS2 isoforms within the CBC in the cytoplasm has dramatic functional consequences, changing ARS2 from a NMD inhibitor to a NMD promoter that enhances the binding of UPF1 to NCBP1 and ERF1, favouring SURF complex formation, SMG7 recruitment and transcript degradation. ARS2 isoform exchange is also relevant during arsenic stress, where cytoplasmic ARS2 promotes a global response to arsenic in a CBC-independent manner. We propose that ARS2 isoform switching promotes the proper recruitment of RNP complexes during NMD and the cellular response to arsenic stress. The existence of non-redundant ARS2 isoforms is relevant for cell homeostasis, and stress response.
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Affiliation(s)
- Monica Mesa-Perez
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | | | - Alex Miranda
- Deeley Research Centre, BC Cancer, Victoria, BC V8R 6V5, Canada
| | - Nicholas Brodie
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Connor O’Sullivan
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jennifer Christie
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Bridget C Ryan
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - David Goodlett
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
- University of Victoria Genome BC Proteomics Centre, Vancouver Island Technology Park, Victoria, BC V8Z 7X8, Canada
| | - Christopher J Nelson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Perry L Howard
- To whom correspondence should be addressed. Tel: +1 260 721 7068; Fax: +1 260 721 8855;
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7
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Mars JC, Ghram M, Culjkovic-Kraljacic B, Borden KLB. The Cap-Binding Complex CBC and the Eukaryotic Translation Factor eIF4E: Co-Conspirators in Cap-Dependent RNA Maturation and Translation. Cancers (Basel) 2021; 13:6185. [PMID: 34944805 PMCID: PMC8699206 DOI: 10.3390/cancers13246185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022] Open
Abstract
The translation of RNA into protein is a dynamic process which is heavily regulated during normal cell physiology and can be dysregulated in human malignancies. Its dysregulation can impact selected groups of RNAs, modifying protein levels independently of transcription. Integral to their suitability for translation, RNAs undergo a series of maturation steps including the addition of the m7G cap on the 5' end of RNAs, splicing, as well as cleavage and polyadenylation (CPA). Importantly, each of these steps can be coopted to modify the transcript signal. Factors that bind the m7G cap escort these RNAs through different steps of maturation and thus govern the physical nature of the final transcript product presented to the translation machinery. Here, we describe these steps and how the major m7G cap-binding factors in mammalian cells, the cap binding complex (CBC) and the eukaryotic translation initiation factor eIF4E, are positioned to chaperone transcripts through RNA maturation, nuclear export, and translation in a transcript-specific manner. To conceptualize a framework for the flow and integration of this genetic information, we discuss RNA maturation models and how these integrate with translation. Finally, we discuss how these processes can be coopted by cancer cells and means to target these in malignancy.
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Affiliation(s)
- Jean-Clement Mars
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Mehdi Ghram
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Katherine L B Borden
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
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8
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ARS2/SRRT: at the nexus of RNA polymerase II transcription, transcript maturation and quality control. Biochem Soc Trans 2021; 49:1325-1336. [PMID: 34060620 DOI: 10.1042/bst20201008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 01/26/2023]
Abstract
ARS2/SRRT is an essential eukaryotic protein that has emerged as a critical factor in the sorting of functional from non-functional RNA polymerase II (Pol II) transcripts. Through its interaction with the Cap Binding Complex (CBC), it associates with the cap of newly made RNAs and acts as a hub for competitive exchanges of protein factors that ultimately determine the fate of the associated RNA. The central position of the protein within the nuclear gene expression machinery likely explains why its depletion causes a broad range of phenotypes, yet an exact function of the protein remains elusive. Here, we consider the literature on ARS2/SRRT with the attempt to garner the threads into a unifying working model for ARS2/SRRT function at the nexus of Pol II transcription, transcript maturation and quality control.
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9
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Rambout X, Maquat LE. The nuclear cap-binding complex as choreographer of gene transcription and pre-mRNA processing. Genes Dev 2021; 34:1113-1127. [PMID: 32873578 PMCID: PMC7462061 DOI: 10.1101/gad.339986.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this review, Rambout and Maquat discuss known roles of the nuclear cap-binding complex (CBC) during the transcription of genes that encode proteins, stitching together past studies from diverse groups to describe the continuum of CBC-mediated checks and balances in eukaryotic cells. The largely nuclear cap-binding complex (CBC) binds to the 5′ caps of RNA polymerase II (RNAPII)-synthesized transcripts and serves as a dynamic interaction platform for a myriad of RNA processing factors that regulate gene expression. While influence of the CBC can extend into the cytoplasm, here we review the roles of the CBC in the nucleus, with a focus on protein-coding genes. We discuss differences between CBC function in yeast and mammals, covering the steps of transcription initiation, release of RNAPII from pausing, transcription elongation, cotranscriptional pre-mRNA splicing, transcription termination, and consequences of spurious transcription. We describe parameters known to control the binding of generic or gene-specific cofactors that regulate CBC activities depending on the process(es) targeted, illustrating how the CBC is an ever-changing choreographer of gene expression.
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Affiliation(s)
- Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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10
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Melko M, Winczura K, Rouvière JO, Oborská-Oplová M, Andersen PK, Heick Jensen T. Mapping domains of ARS2 critical for its RNA decay capacity. Nucleic Acids Res 2020; 48:6943-6953. [PMID: 32463452 PMCID: PMC7337933 DOI: 10.1093/nar/gkaa445] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 02/06/2023] Open
Abstract
ARS2 is a conserved protein centrally involved in both nuclear RNA productive and destructive processes. To map features of ARS2 promoting RNA decay, we utilized two different RNA reporters, one of which depends on direct ARS2 tethering for its degradation. In both cases, ARS2 triggers a degradation phenotype aided by its interaction with the poly(A) tail exosome targeting (PAXT) connection. Interestingly, C-terminal amino acids of ARS2, responsible for binding the RNA 5′cap binding complex (CBC), become dispensable when ARS2 is directly tethered to the reporter RNA. In contrast, the Zinc-finger (ZnF) domain of ARS2 is essential for the decay of both reporters and consistently co-immunoprecipitation analyses reveal a necessity of this domain for the interaction of ARS2 with the PAXT-associated RNA helicase MTR4. Taken together, our results map the domains of ARS2 underlying two essential properties of the protein: its RNP targeting ability and its capacity to recruit the RNA decay machinery.
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Affiliation(s)
- Mireille Melko
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Kinga Winczura
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Jérôme Olivier Rouvière
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Michaela Oborská-Oplová
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Pia K Andersen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
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11
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Kainov YA, Makeyev EV. A transcriptome-wide antitermination mechanism sustaining identity of embryonic stem cells. Nat Commun 2020; 11:361. [PMID: 31953406 PMCID: PMC6969169 DOI: 10.1038/s41467-019-14204-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 12/11/2019] [Indexed: 11/29/2022] Open
Abstract
Eukaryotic gene expression relies on extensive crosstalk between transcription and RNA processing. Changes in this composite regulation network may provide an important means for shaping cell type-specific transcriptomes. Here we show that the RNA-associated protein Srrt/Ars2 sustains embryonic stem cell (ESC) identity by preventing premature termination of numerous transcripts at cryptic cleavage/polyadenylation sites in first introns. Srrt interacts with the nuclear cap-binding complex and facilitates recruitment of the spliceosome component U1 snRNP to cognate intronic positions. At least in some cases, U1 recruited in this manner inhibits downstream cleavage/polyadenylation events through a splicing-independent mechanism called telescripting. We further provide evidence that the naturally high expression of Srrt in ESCs offsets deleterious effects of retrotransposable sequences accumulating in its targets. Our work identifies Srrt as a molecular guardian of the pluripotent cell state. Besides its role in splicing, U1 snRNP can suppress pre-mRNA cleavage and polyadenylation. The authors show that the nuclear cap-binding complex component Srrt/Ars2 maintains embryonic stem cell identity by promoting U1 recruitment to first introns and preventing premature termination of multiple transcripts.
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Affiliation(s)
- Yaroslav A Kainov
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
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12
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Garland W, Jensen TH. Nuclear sorting of RNA. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1572. [PMID: 31713323 DOI: 10.1002/wrna.1572] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 12/27/2022]
Abstract
The majority of the mammalian genome is transcribed by RNA polymerase II, yielding a vast amount of noncoding RNA (ncRNA) in addition to the standard production of mRNA. The typical nuclear biogenesis of mRNA relies on the tightly controlled coupling of co- and post-transcriptional processing events, which ultimately results in the export of transcripts into the cytoplasm. These processes are subject to surveillance by nuclear RNA decay pathways to prevent the export of aberrant, or otherwise "non-optimal," transcripts. However, unlike mRNA, many long ncRNAs are nuclear retained and those that maintain enduring functions must employ precautions to evade decay. Proper sorting and localization of RNA is therefore an essential activity in eukaryotic cells and the formation of ribonucleoprotein complexes during early stages of RNA synthesis is central to deciding such transcript fate. This review details our current understanding of the pathways and factors that direct RNAs towards a particular destiny and how transcripts combat the adverse conditions of the nucleus. This article is categorized under: RNA Export and Localization > Nuclear Export/Import RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- William Garland
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C., Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C., Denmark
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13
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Bui DC, Kim JE, Shin J, Lim JY, Choi GJ, Lee YW, Seo JA, Son H. ARS2 Plays Diverse Roles in DNA Damage Response, Fungal Development, and Pathogenesis in the Plant Pathogenic Fungus Fusarium graminearum. Front Microbiol 2019; 10:2326. [PMID: 31681199 PMCID: PMC6803386 DOI: 10.3389/fmicb.2019.02326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/24/2019] [Indexed: 11/13/2022] Open
Abstract
Arsenite-resistance protein 2 (Ars2) is an important nuclear protein involved in various RNA metabolisms in animals and plants, but no Ars2 ortholog has been studied in filamentous fungi. Although it is an essential gene in most model eukaryotes, FgARS2 null mutants were viable in the plant pathogenic fungus Fusarium graminearum. The deletion of FgARS2 resulted in pleiotropic defects in various fungal developmental processes. Fgars2 mutants were irregular in nuclear division, and conidial germination was significantly retarded, causing the fungus to manifest its hypersensitive phenotypes under DNA damage stress. While FgARS2 deletion caused abnormal morphologies of ascospores and defective ascospore discharge, our data revealed that FgARS2 was not closely involved in small-non-coding RNA production in F. graminearum. The dominant nuclear localization of FgArs2-green fluorescent proteins (GFP) and abnormal nuclear division in FgARS2 deletion mutant implicated that FgArs2 functions in the nucleus. Intriguingly, we found that FgArs2 established a robust physical interaction with the cap binding complex (CBC) to form a tertiary complex CBC-Ars2 (CBCA), and disruption of any CBCA complex subunit drastically attenuated the virulence of F. graminearum. The results of the study indicate that Ars2 regulates fungal development, stress response, and pathogenesis via interaction with CBC in F. graminearum and provide a novel insight into understanding of the biological functions of Ars2 in filamentous fungi.
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Affiliation(s)
- Duc-Cuong Bui
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.,School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Jung-Eun Kim
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jiyoung Shin
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jae Yun Lim
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Gyung Ja Choi
- Therapeutic & Biotechnology Division, Center for Eco-Friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Jeong-Ah Seo
- School of Systems Biomedical Science, Soongsil University, Seoul, South Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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14
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O'Sullivan C, Nickerson PEB, Krupke O, Christie J, Chen LL, Mesa-Peres M, Zhu M, Ryan B, Chow RL, Howard PL. ARS2 is required for retinal progenitor cell S-phase progression and Müller glial cell fate specification. Biochem Cell Biol 2019; 98:50-60. [PMID: 30673303 DOI: 10.1139/bcb-2018-0250] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
During a developmental period that extends postnatally in the mouse, proliferating multipotent retinal progenitor cells produce one of 7 major cell types (rod, cone, bipolar, horizontal, amacrine, ganglion, and Müller glial cells) as they exit the cell cycle in consecutive waves. Cell production in the retina is tightly regulated by intrinsic, extrinsic, spatial, and temporal cues, and is coupled to the timing of cell cycle exit. Arsenic-resistance protein 2 (ARS2, also known as SRRT) is a component of the nuclear cap-binding complex involved in RNA Polymerase II transcription, and is required for cell cycle progression. We show that postnatal retinal progenitor cells (RPCs) require ARS2 for proper progression through S phase, and ARS2 disruption leads to early exit from the cell cycle. Furthermore, we observe an increase in the proportion of cells expressing a rod photoreceptor marker, and a loss of Müller glia marker expression, indicating a role for ARS2 in regulating cell fate specification or differentiation. Knockdown of Flice Associated Huge protein (FLASH), which interacts with ARS2 and is required for cell cycle progression and 3'-end processing of replication-dependent histone transcripts, phenocopies ARS2 knockdown. These data implicate ARS2-FLASH-mediated histone mRNA processing in regulating RPC cell cycle kinetics and neuroglial cell fate specification during postnatal retinal development.
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Affiliation(s)
- Connor O'Sullivan
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | | | - Oliver Krupke
- Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Jennifer Christie
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Li-Li Chen
- Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Monica Mesa-Peres
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Minyan Zhu
- Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Bridget Ryan
- Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - Perry L Howard
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 2Y2, Canada
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15
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Hu X, Xu S, Chen Y, Gao Z, Li Y, Hu J, Huang X, Zhang Y, Jiang X, Li L, Yang C, Chen J, Gao N. Depletion of Ars2 inhibits cell proliferation and leukemogenesis in acute myeloid leukemia by modulating the miR-6734-3p/p27 axis. Leukemia 2018; 33:1090-1101. [PMID: 30518811 PMCID: PMC6756072 DOI: 10.1038/s41375-018-0301-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/03/2018] [Accepted: 09/20/2018] [Indexed: 01/16/2023]
Abstract
Ars2 is a component of the nuclear cap-binding complex (CBC) that contributes to microRNA biogenesis and is required for cellular proliferation. Little is known regarding the functional role of Ars2 in cell proliferation and leukemogenesis of acute myeloid leukemia. Here, we show that the elevated expression of Ars2 was observed in acute myeloid leukemia (AML) cell lines and bone marrow samples from AML patients and was correlated with poorer overall survival. Overexpression of Ars2 promoted cell proliferation and colony formation in AML cells, whereas depletion of Ars2 inhibited cell proliferation and colony formation. Mechanistic studies reveal that depletion of Ars2 suppressed the interaction of Ars2 with CBC and led to alterations in miRNA processing. Furthermore, Ars2 depletion reduced the levels of miR-6734-3p, resulting in upregulation of p27 and culminating in cell cycle arrest at the G1 phase. In vivo studies indicate that depletion of Ars2 significantly reduced leukemic cell burden and prolonged the survival time of the leukemia-bearing mice. These findings indicate that Ars2 may not only play a crucial role in the regulation of cell proliferation and leukemogenesis, but could also be identified as a critical therapeutic target for treatment of AML.
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Affiliation(s)
- Xiaoye Hu
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Shuangnian Xu
- Department of Hematology, Southwest Hospital, Army Medical University, Chongqing, China
| | - Yibiao Chen
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Ziyi Gao
- Greater Philadelphia Pharmacy, Philadelphia, PA, USA
| | - Yunong Li
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Jinjiao Hu
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Xiuning Huang
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Yanhao Zhang
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Xiuxing Jiang
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Lirong Li
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Chong Yang
- College of Pharmacy, Army Medical University, Chongqing, China
| | - Jieping Chen
- Department of Hematology, Southwest Hospital, Army Medical University, Chongqing, China.
| | - Ning Gao
- College of Pharmacy, Army Medical University, Chongqing, China. .,Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, China.
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16
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Chen Y, Hu X, Li Y, Zhang H, Fu R, Liu Y, Hu J, Deng Q, Luo Q, Zhang D, Gao N, Cui H. Ars2 promotes cell proliferation and tumorigenicity in glioblastoma through regulating miR-6798-3p. Sci Rep 2018; 8:15602. [PMID: 30349053 PMCID: PMC6197286 DOI: 10.1038/s41598-018-33905-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 10/08/2018] [Indexed: 12/15/2022] Open
Abstract
Arsenic resistance protein 2 (Ars2) is a component of the nuclear RNA cap-binding complex (CBC) that is important for some microRNA biogenesis and it is critical for cell proliferation and tumorigenicity. However, mechanism of Ars2-regulated cellular proliferation and tumorigenicity in glioblastoma has not been fully understood. Western blotting was used to detect the expressions of Ars2, p53, p21, and cleavage/activation of caspases-3 (C-Caspase 3). Microarray and Quantitative Real-time PCR (qRT-PCR) were performed to identify the Ars2-regulated microRNAs. Apoptosis assessed by flow cytometry analysis was used to evaluate the role of Ars2 in cells proliferation. The lentivirus-mediated gene knockdown approach was conducted to determine the function of Ars2. The orthotopic glioblastoma xenograft was used to demonstrate the role of Ars2 in glioblastoma growth in vivo. The high expression of Ars2 was observed in several glioblastoma cell lines and was significantly associated with poorer overall survival. Importantly, the overexpression of Ars2 promoted cell proliferation and colony formation in glioblastoma cells, whereas the depletion of Ars2 inhibited cell proliferation, colony formation, and tumor growth. Mechanistic study revealed that knockdown of Ars2 reduced the expression levels of miR-6798-3p, which was responsible for the up-regulation of p53 and p21, leading to apoptosis. Furthermore, the knockdown of Ars2 suppressed tumor growth in orthotopic glioblastoma xenograft model and significantly prolonged the survival time of the tumor-bearing mice. These findings identify a critical role for Ars2 in regulation of proliferation and tumorigenicity in glioblastoma and suggest that Ars2 could be a critical therapeutic target for glioblastoma intervention.
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Affiliation(s)
- Yibiao Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Xiaoye Hu
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Yunong Li
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Hongwei Zhang
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Ruoqiu Fu
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Yanxia Liu
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Jinjiao Hu
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Qin Deng
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Qingsong Luo
- College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Dunke Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Ning Gao
- College of Pharmacy, Third Military Medical University, Chongqing, China.
| | - Hongjuan Cui
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China.
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17
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The RNA binding protein Ars2 supports hematopoiesis at multiple levels. Exp Hematol 2018; 64:45-58.e9. [PMID: 29775646 DOI: 10.1016/j.exphem.2018.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/01/2018] [Accepted: 05/08/2018] [Indexed: 12/22/2022]
Abstract
Recent biochemical characterization of arsenic resistance protein 2 (Ars2) has established it as central in determining the fate of nascent ribonucleic acid (RNA) polymerase II (RNAPII) transcripts. Through interactions with the nuclear 5'-7-methylguanosine cap-binding complex, Ars2 promotes cotranscriptional processing coupled with nuclear export or degradation of several classes of RNAPII transcripts, allowing for gene expression programs that facilitate rapid and sustained proliferation of immortalized cells in culture. However, rapidly dividing cells in culture do not represent the physiological condition of the vast majority of cells in an adult mammal. To examine functions of Ars2 in a physiological setting, we generated inducible Ars2 knockout mice and found that deletion of Ars2 from adult mice resulted in defective hematopoiesis in bone marrow and thymus. Importantly, only some of this defect could be explained by the requirement of Ars2 for rapid proliferation, which we found to be cell-type specific in vivo. Rather, Ars2 was required for survival of developing thymocytes and for limiting differentiation of bone marrow resident long-term hematopoietic stem cells. As a result, Ars2 knockout led to rapid thymic involution and loss of the ability of mice to regenerate peripheral blood after myeloablation. These in vivo data demonstrate that Ars2 expression is important at several steps of hematopoiesis, likely because Ars2 acts on gene expression programs underlying essential cell fate decisions such as the decision to die,proliferate, or differentiate.
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18
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Structural analysis of human ARS2 as a platform for co-transcriptional RNA sorting. Nat Commun 2018; 9:1701. [PMID: 29703953 PMCID: PMC5923425 DOI: 10.1038/s41467-018-04142-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/06/2018] [Indexed: 02/08/2023] Open
Abstract
ARS2 is a highly conserved metazoan protein involved in numerous aspects of nuclear RNA metabolism. As a direct partner of the nuclear cap-binding complex (CBC), it mediates interactions with diverse RNA processing and transport machineries in a transcript-dependent manner. Here, we present the human ARS2 crystal structure, which exhibits similarities and metazoan-specific differences to the plant homologue SERRATE, most notably an additional RRM domain. We present biochemical, biophysical and cellular interactome data comparing wild type and mutant ARS2 that identify regions critical for interactions with FLASH (involved in histone mRNA biogenesis), NCBP3 (a putative cap-binding protein involved in mRNA export) and single-stranded RNA. We show that FLASH and NCBP3 have overlapping binding sites on ARS2 and that CBC–ARS2–NCBP3 form a ternary complex that is mutually exclusive with CBC–ARS–PHAX (involved in snRNA export). Our results support that mutually exclusive higher-order CBC–ARS2 complexes are critical in determining Pol II transcript fate. Arsenic resistance protein 2 (ARS2) plays an important role in nuclear RNA metabolism and interacts with the nuclear cap-binding complex (CBC). Here the authors present the human ARS2 structure and identify regions important for its interactions with binding partners supporting that mutually exclusive higher order CBC-ARS2 complexes are formed.
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19
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Structural basis for mutually exclusive co-transcriptional nuclear cap-binding complexes with either NELF-E or ARS2. Nat Commun 2017; 8:1302. [PMID: 29101316 PMCID: PMC5670239 DOI: 10.1038/s41467-017-01402-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 09/14/2017] [Indexed: 12/12/2022] Open
Abstract
Pol II transcribes diverse classes of RNAs that need to be directed into the appropriate nuclear maturation pathway. All nascent Pol II transcripts are 5′-capped and the cap is immediately sequestered by the nuclear cap-binding complex (CBC). Mutually exclusive interactions of CBC with different partner proteins have been implicated in transcript fate determination. Here, we characterise the direct interactions between CBC and NELF-E, a subunit of the negative elongation factor complex, ARS2 and PHAX. Our biochemical and crystal structure results show that the homologous C-terminal peptides of NELF-E and ARS2 bind identically to CBC and in each case the affinity is enhanced when CBC is bound to a cap analogue. Furthermore, whereas PHAX forms a complex with CBC and ARS2, NELF-E binding to CBC is incompatible with PHAX binding. We thus define two mutually exclusive complexes CBC–NELF–E and CBC–ARS2–PHAX, which likely act in respectively earlier and later phases of transcription. The nuclear cap-binding complex (CBC) binds to the 5′-cap structure of Pol II transcripts. Here, the authors give structural insights into CBC-mediated transcript processing and show that CBC forms mutual exclusive complexes with NELF and ARS2, which might act in earlier and later phases of transcription, respectively.
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