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Bao J, Su B, Chen Z, Sun Z, Peng J, Zhao S. A UTP3-dependent nucleolar translocation pathway facilitates pre-rRNA 5'ETS processing. Nucleic Acids Res 2024:gkae631. [PMID: 39036955 DOI: 10.1093/nar/gkae631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 06/27/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024] Open
Abstract
The ribosome small subunit (SSU) is assembled by the SSU processome which contains approximately 70 non-ribosomal protein factors. Whilst the biochemical mechanisms of the SSU processome in 18S rRNA processing and maturation have been extensively studied, how SSU processome components enter the nucleolus has yet to be systematically investigated. Here, in examining the nucleolar localization of 50 human SSU processome components, we found that UTP3, together with another 24 proteins, enter the nucleolus autonomously. For the remaining 25 proteins we found that UTP3/SAS10 assists the nucleolar localization of five proteins (MPP10, UTP25, EMG1 and the two UTP-B components UTP12 and UTP13), likely through its interaction with nuclear importin α. This 'ferrying' function of UTP3 was then confirmed as conserved in the zebrafish. We also found that knockdown of human UTP3 impairs cleavage at the A0-site while loss-of-function of either utp3/sas10 or utp13/tbl3 in zebrafish causes the accumulation of aberrantly processed 5'ETS products, which highlights the crucial role of UTP3 in mediating 5'ETS processing. Mechanistically, we found that UTP3 facilitates the degradation of processed 5'ETS by recruiting the RNA exosome component EXOSC10 to the nucleolus. These findings lay the groundwork for studying the mechanism of cytoplasm-to-nucleolus trafficking of SSU processome components.
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Affiliation(s)
- Jiayang Bao
- MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Baochun Su
- MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zheyan Chen
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhaoxiang Sun
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jinrong Peng
- MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shuyi Zhao
- MOE Key Laboratory for Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
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2
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Filippopoulou C, Thomé CC, Perdikari S, Ntini E, Simos G, Bohnsack KE, Chachami G. Hypoxia-driven deSUMOylation of EXOSC10 promotes adaptive changes in the transcriptome profile. Cell Mol Life Sci 2024; 81:58. [PMID: 38279024 PMCID: PMC10817850 DOI: 10.1007/s00018-023-05035-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/12/2023] [Accepted: 11/06/2023] [Indexed: 01/28/2024]
Abstract
Reduced oxygen availability (hypoxia) triggers adaptive cellular responses via hypoxia-inducible factor (HIF)-dependent transcriptional activation. Adaptation to hypoxia also involves transcription-independent processes like post-translational modifications; however, these mechanisms are poorly characterized. Investigating the involvement of protein SUMOylation in response to hypoxia, we discovered that hypoxia strongly decreases the SUMOylation of Exosome subunit 10 (EXOSC10), the catalytic subunit of the RNA exosome, in an HIF-independent manner. EXOSC10 is a multifunctional exoribonuclease enriched in the nucleolus that mediates the processing and degradation of various RNA species. We demonstrate that the ubiquitin-specific protease 36 (USP36) SUMOylates EXOSC10 and we reveal SUMO1/sentrin-specific peptidase 3 (SENP3) as the enzyme-mediating deSUMOylation of EXOSC10. Under hypoxia, EXOSC10 dissociates from USP36 and translocates from the nucleolus to the nucleoplasm concomitant with its deSUMOylation. Loss of EXOSC10 SUMOylation does not detectably affect rRNA maturation but affects the mRNA transcriptome by modulating the expression levels of hypoxia-related genes. Our data suggest that dynamic modulation of EXOSC10 SUMOylation and localization under hypoxia regulates the RNA degradation machinery to facilitate cellular adaptation to low oxygen conditions.
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Affiliation(s)
- Chrysa Filippopoulou
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - Chairini C Thomé
- Department of Molecular Biology, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Sofia Perdikari
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas (FORTH), 70013, Heraklion, Greece
| | - Evgenia Ntini
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas (FORTH), 70013, Heraklion, Greece
| | - George Simos
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece
- Gerald Bronfman Department of Oncology, Faculty of Medicine, McGill University, Montreal, Canada
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Georgia Chachami
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Biopolis, 41500, Larissa, Greece.
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3
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Yim MK, Stuart CJ, Pond MI, van Hoof A, Johnson SJ. Conserved Residues at the Mtr4 C-Terminus Coordinate Helicase Activity and Exosome Interactions. Biochemistry 2024; 63:159-170. [PMID: 38085597 PMCID: PMC10984559 DOI: 10.1021/acs.biochem.3c00401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Mtr4 is an essential RNA helicase involved in nuclear RNA processing and degradation and is a member of the Ski2-like helicase family. Ski2-like helicases share a common core architecture that includes two RecA-like domains, a winged helix, and a helical bundle (HB) domain. In Mtr4, a short C-terminal tail immediately follows the HB domain and is positioned at the interface of the RecA-like domains. The tail ends with a SLYΦ sequence motif that is highly conserved in a subset of Ski2-like helicases. Here, we show that this sequence is critical for Mtr4 function. Mutations in the C-terminus result in decreased RNA unwinding activity. Mtr4 is a key activator of the RNA exosome complex, and mutations in the SLYΦ motif produce a slow growth phenotype when combined with a partial exosome defect in S. cerevisiae, suggesting an important role of the C-terminus of Mtr4 and the RNA exosome. We further demonstrate that C-terminal mutations impair RNA degradation activity by the major RNA exosome nuclease Rrp44 in vitro. These data demonstrate a role for the Mtr4 C-terminus in regulating helicase activity and coordinating Mtr4-exosome interactions.
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Affiliation(s)
- Matthew K. Yim
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322, USA
| | - Catherine J. Stuart
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas, 77030, USA
| | - Markell I. Pond
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas, 77030, USA
| | - Sean J. Johnson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, 84322, USA
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4
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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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5
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Keidel A, Kögel A, Reichelt P, Kowalinski E, Schäfer IB, Conti E. Concerted structural rearrangements enable RNA channeling into the cytoplasmic Ski238-Ski7-exosome assembly. Mol Cell 2023; 83:4093-4105.e7. [PMID: 37879335 PMCID: PMC10659929 DOI: 10.1016/j.molcel.2023.09.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/25/2023] [Accepted: 09/29/2023] [Indexed: 10/27/2023]
Abstract
The Ski2-Ski3-Ski8 (Ski238) helicase complex directs cytoplasmic mRNAs toward the nucleolytic exosome complex for degradation. In yeast, the interaction between Ski238 and exosome requires the adaptor protein Ski7. We determined different cryo-EM structures of the Ski238 complex depicting the transition from a rigid autoinhibited closed conformation to a flexible active open conformation in which the Ski2 helicase module has detached from the rest of Ski238. The open conformation favors the interaction of the Ski3 subunit with exosome-bound Ski7, leading to the recruitment of the exosome. In the Ski238-Ski7-exosome holocomplex, the Ski2 helicase module binds the exosome cap, enabling the RNA to traverse from the helicase through the internal exosome channel to the Rrp44 exoribonuclease. Our study pinpoints how conformational changes within the Ski238 complex regulate exosome recruitment for RNA degradation. We also reveal the remarkable conservation of helicase-exosome RNA channeling mechanisms throughout eukaryotic nuclear and cytoplasmic exosome complexes.
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Affiliation(s)
- Achim Keidel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Alexander Kögel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Peter Reichelt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Eva Kowalinski
- EMBL Grenoble, 71 Avenue des Martyrs, 38072 Grenoble, France
| | - Ingmar B Schäfer
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, 82152 Munich, Germany.
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6
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Sterrett MC, Cureton LA, Cohen LN, van Hoof A, Khoshnevis S, Fasken MB, Corbett AH, Ghalei H. Comparative analyses of disease-linked missense mutations in the RNA exosome modeled in budding yeast reveal distinct functional consequences in translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562946. [PMID: 37904946 PMCID: PMC10614903 DOI: 10.1101/2023.10.18.562946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The RNA exosome is an evolutionarily conserved exoribonuclease complex that consists of a 3-subunit cap, a 6-subunit barrel-shaped core, and a catalytic base subunit. Missense mutations in genes encoding structural subunits of the RNA exosome cause a growing family of diseases with diverse pathologies, collectively termed RNA exosomopathies. The disease symptoms vary and can manifest as neurological defects or developmental disorders. The diversity of the RNA exosomopathy pathologies suggests that the different missense mutations in structural genes result in distinct in vivo consequences. To investigate these functional consequences and distinguish whether they are unique to each RNA exosomopathy mutation, we generated a collection of in vivo models using budding yeast by introducing pathogenic missense mutations in orthologous S. cerevisiae genes. We then performed a comparative RNA-seq analysis to assess broad transcriptomic changes in each mutant model. Three of the mutant models rrp4-G226D, rrp40-W195R and rrp46-L191H, which model mutations in the genes encoding structural subunits of the RNA exosome, EXOSC2, EXOSC3 and EXOSC5 showed the largest transcriptomic differences. Further analyses revealed shared increased transcripts enriched in translation or ribosomal RNA modification/processing pathways across the three mutant models. Studies of the impact of the mutations on translation revealed shared defects in ribosome biogenesis but distinct impacts on translation. Collectively, our results provide the first comparative analysis of several RNA exosomopathy mutant models and suggest that different RNA exosomopathy mutations result in in vivo consequences that are both unique and shared across each variant, providing more insight into the biology underlying each distinct pathology.
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Affiliation(s)
- Maria C. Sterrett
- Department of Biology, Emory University, Atlanta, Georgia, USA
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia, USA
| | - Lauryn A. Cureton
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, Georgia, USA
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Lauren N. Cohen
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Sohail Khoshnevis
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Milo B. Fasken
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | | | - Homa Ghalei
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
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7
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Sterrett MC, Farchi D, Strassler SE, Boise LH, Fasken MB, Corbett AH. In vivo characterization of the critical interaction between the RNA exosome and the essential RNA helicase Mtr4 in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2023; 13:jkad049. [PMID: 36861343 PMCID: PMC10411580 DOI: 10.1093/g3journal/jkad049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/05/2023] [Accepted: 02/10/2023] [Indexed: 03/03/2023]
Abstract
The RNA exosome is a conserved molecular machine that processes/degrades numerous coding and non-coding RNAs. The 10-subunit complex is composed of three S1/KH cap subunits (human EXOSC2/3/1; yeast Rrp4/40/Csl4), a lower ring of six PH-like subunits (human EXOSC4/7/8/9/5/6; yeast Rrp41/42/43/45/46/Mtr3), and a singular 3'-5' exo/endonuclease DIS3/Rrp44. Recently, several disease-linked missense mutations have been identified in structural cap and core RNA exosome genes. In this study, we characterize a rare multiple myeloma patient missense mutation that was identified in the cap subunit gene EXOSC2. This missense mutation results in a single amino acid substitution, p.Met40Thr, in a highly conserved domain of EXOSC2. Structural studies suggest that this Met40 residue makes direct contact with the essential RNA helicase, MTR4, and may help stabilize the critical interaction between the RNA exosome complex and this cofactor. To assess this interaction in vivo, we utilized the Saccharomyces cerevisiae system and modeled the EXOSC2 patient mutation into the orthologous yeast gene RRP4, generating the variant rrp4-M68T. The rrp4-M68T cells show accumulation of certain RNA exosome target RNAs and show sensitivity to drugs that impact RNA processing. We also identified robust negative genetic interactions between rrp4-M68T and specific mtr4 mutants. A complementary biochemical approach revealed that Rrp4 M68T shows decreased interaction with Mtr4, consistent with these genetic results. This study suggests that the EXOSC2 mutation identified in a multiple myeloma patient impacts the function of the RNA exosome and provides functional insight into a critical interface between the RNA exosome and Mtr4.
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Affiliation(s)
- Maria C Sterrett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322, USA
| | - Daniela Farchi
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Sarah E Strassler
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322, USA
- Department of Biochemistry, Emory University, Atlanta, GA, 30322, USA
| | - Lawrence H Boise
- Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Milo B Fasken
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
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8
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Schneider C, Bohnsack KE. Caught in the act-Visualizing ribonucleases during eukaryotic ribosome assembly. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1766. [PMID: 36254602 DOI: 10.1002/wrna.1766] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 07/20/2023]
Abstract
Ribosomes are essential macromolecular machines responsible for translating the genetic information encoded in mRNAs into proteins. Ribosomes are composed of ribosomal RNAs and proteins (rRNAs and RPs) and the rRNAs fulfill both catalytic and architectural functions. Excision of the mature eukaryotic rRNAs from their precursor transcript is achieved through a complex series of endoribonucleolytic cleavages and exoribonucleolytic processing steps that are precisely coordinated with other aspects of ribosome assembly. Many ribonucleases involved in pre-rRNA processing have been identified and pre-rRNA processing pathways are relatively well defined. However, momentous advances in cryo-electron microscopy have recently enabled structural snapshots of various pre-ribosomal particles from budding yeast (Saccharomyces cerevisiae) and human cells to be captured and, excitingly, these structures not only allow pre-rRNAs to be observed before and after cleavage events, but also enable ribonucleases to be visualized on their target RNAs. These structural views of pre-rRNA processing in action allow a new layer of understanding of rRNA maturation and how it is coordinated with other aspects of ribosome assembly. They illuminate mechanisms of target recognition by the diverse ribonucleases involved and reveal how the cleavage/processing activities of these enzymes are regulated. In this review, we discuss the new insights into pre-rRNA processing gained by structural analyses and the growing understanding of the mechanisms of ribonuclease regulation. This article is categorized under: Translation > Ribosome Biogenesis RNA Processing > rRNA Processing.
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Affiliation(s)
- Claudia Schneider
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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9
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Xu T, Liao S, Huang M, Zhu C, Huang X, Jin Q, Xu D, Fu C, Chen X, Feng X, Guang S. A ZTF-7/RPS-2 complex mediates the cold-warm response in C. elegans. PLoS Genet 2023; 19:e1010628. [PMID: 36763670 PMCID: PMC9949642 DOI: 10.1371/journal.pgen.1010628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 02/23/2023] [Accepted: 01/20/2023] [Indexed: 02/12/2023] Open
Abstract
Temperature greatly affects numerous biological processes in all organisms. How multicellular organisms respond to and are impacted by hypothermic stress remains elusive. Here, we found that cold-warm stimuli induced depletion of the RNA exosome complex in the nucleoli but enriched it in the nucleoplasm. To further understand the function and mechanism of cold-warm stimuli, we conducted forward genetic screening and identified ZTF-7, which is required for RNA exosome depletion from nucleoli upon transient cold-warm exposure in C. elegans. ZTF-7 is a putative ortholog of human ZNF277 that may contribute to language impairments. Immunoprecipitation followed by mass spectrometry (IP-MS) found that ZTF-7 interacted with RPS-2, which is a ribosomal protein of the small subunit and participates in pre-rRNA processing. A partial depletion of RPS-2 and other proteins of the small ribosomal subunit blocked the cold-warm stimuli-induced reduction of exosome subunits from the nucleoli. These results established a novel mechanism by which C. elegans responds to environmental cold-warm exposure.
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Affiliation(s)
- Ting Xu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Shimiao Liao
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Meng Huang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Chengming Zhu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaona Huang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Qile Jin
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Demin Xu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Chuanhai Fu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiangyang Chen
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
- * E-mail: (XC); (XF); (SG)
| | - Xuezhu Feng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
- * E-mail: (XC); (XF); (SG)
| | - Shouhong Guang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui, China
- CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, Anhui, China
- * E-mail: (XC); (XF); (SG)
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10
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Webster SF, Ghalei H. Maturation of small nucleolar RNAs: from production to function. RNA Biol 2023; 20:715-736. [PMID: 37796118 PMCID: PMC10557570 DOI: 10.1080/15476286.2023.2254540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Small Nucleolar RNAs (snoRNAs) are an abundant group of non-coding RNAs with well-defined roles in ribosomal RNA processing, folding and chemical modification. Besides their classic roles in ribosome biogenesis, snoRNAs are also implicated in several other cellular activities including regulation of splicing, transcription, RNA editing, cellular trafficking, and miRNA-like functions. Mature snoRNAs must undergo a series of processing steps tightly regulated by transiently associating factors and coordinated with other cellular processes including transcription and splicing. In addition to their mature forms, snoRNAs can contribute to gene expression regulation through their derivatives and degradation products. Here, we review the current knowledge on mechanisms of snoRNA maturation, including the different pathways of processing, and the regulatory mechanisms that control snoRNA levels and complex assembly. We also discuss the significance of studying snoRNA maturation, highlight the gaps in the current knowledge and suggest directions for future research in this area.
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Affiliation(s)
- Sarah F. Webster
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia, USA
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
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11
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Fujiwara N, Shigemoto M, Hirayama M, Fujita KI, Seno S, Matsuda H, Nagahama M, Masuda S. MPP6 stimulates both RRP6 and DIS3 to degrade a specified subset of MTR4-sensitive substrates in the human nucleus. Nucleic Acids Res 2022; 50:8779-8806. [PMID: 35902094 PMCID: PMC9410898 DOI: 10.1093/nar/gkac559] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 06/10/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Recent in vitro reconstitution analyses have proven that the physical interaction between the exosome core and MTR4 helicase, which promotes the exosome activity, is maintained by either MPP6 or RRP6. However, knowledge regarding the function of MPP6 with respect to in vivo exosome activity remains scarce. Here, we demonstrate a facilitative function of MPP6 that composes a specific part of MTR4-dependent substrate decay by the human exosome. Using RNA polymerase II-transcribed poly(A)+ substrate accumulation as an indicator of a perturbed exosome, we found functional redundancy between RRP6 and MPP6 in the decay of these poly(A)+ transcripts. MTR4 binding to the exosome core via MPP6 was essential for MPP6 to exert its redundancy with RRP6. However, at least for the decay of our identified exosome substrates, MTR4 recruitment by MPP6 was not functionally equivalent to recruitment by RRP6. Genome-wide classification of substrates based on their sensitivity to each exosome component revealed that MPP6 deals with a specific range of substrates and highlights the importance of MTR4 for their decay. Considering recent findings of competitive binding to the exosome between auxiliary complexes, our results suggest that the MPP6-incorporated MTR4-exosome complex is one of the multiple alternative complexes rather than the prevailing one.
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Affiliation(s)
- Naoko Fujiwara
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8502, Japan
| | - Maki Shigemoto
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8502, Japan
| | - Mizuki Hirayama
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8502, Japan
| | - Ken-Ichi Fujita
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8502, Japan.,Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Shigeto Seno
- Graduate School of Information Science and Technology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hideo Matsuda
- Graduate School of Information Science and Technology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masami Nagahama
- Laboratory of Molecular and Cellular Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588, Japan
| | - Seiji Masuda
- Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8502, Japan.,Department of Food Science and Nutrition, Faculty of Agriculture Kindai University, Nara, Nara 631-8505, Japan.,Agricultural Technology and Innovation Research Institute, Kindai University, Nara, Nara 631-8505, Japan.,Antiaging center, Kindai University, Higashiosaka, Osaka 577-8502, Japan
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12
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Wu M, Schmid M, Jensen T, Sandelin A. Computational identification of signals predictive for nuclear RNA exosome degradation pathway targeting. NAR Genom Bioinform 2022; 4:lqac071. [PMID: 36128426 PMCID: PMC9477074 DOI: 10.1093/nargab/lqac071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/05/2022] [Accepted: 09/01/2022] [Indexed: 11/15/2022] Open
Abstract
The RNA exosome degrades transcripts in the nucleoplasm of mammalian cells. Its substrate specificity is mediated by two adaptors: the ‘nuclear exosome targeting (NEXT)’ complex and the ‘poly(A) exosome targeting (PAXT)’ connection. Previous studies have revealed some DNA/RNA elements that differ between the two pathways, but how informative these features are for distinguishing pathway targeting, or whether additional genomic features that are informative for such classifications exist, is unknown. Here, we leverage the wealth of available genomic data and develop machine learning models that predict exosome targets and subsequently rank the features the models use by their predictive power. As expected, features around transcript end sites were most predictive; specifically, the lack of canonical 3′ end processing was highly predictive of NEXT targets. Other associated features, such as promoter-proximal G/C content and 5′ splice sites, were informative, but only for distinguishing NEXT and not PAXT targets. Finally, we discovered predictive features not previously associated with exosome targeting, in particular RNA helicase DDX3X binding sites. Overall, our results demonstrate that nucleoplasmic exosome targeting is to a large degree predictable, and our approach can assess the predictive power of previously known and new features in an unbiased way.
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Affiliation(s)
- Mengjun Wu
- The Bioinformatics Centre, Department of Biology and Biotech and Research Innovation Centre, University of Copenhagen , Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet , 171 65 Solna , Sweden
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University , Universitetsbyen 81, Aarhus , DK-8000, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University , Universitetsbyen 81, Aarhus , DK-8000, Denmark
| | - Albin Sandelin
- The Bioinformatics Centre, Department of Biology and Biotech and Research Innovation Centre, University of Copenhagen , Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
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13
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Transcriptomic analysis of ribosome biogenesis and pre-rRNA processing during growth stress in Entamoeba histolytica. Exp Parasitol 2022; 239:108308. [PMID: 35718007 DOI: 10.1016/j.exppara.2022.108308] [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: 08/15/2021] [Revised: 05/27/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022]
Abstract
Ribosome biogenesis, a multi-step process involving transcription, modification, folding and processing of rRNA, is the major consumer of cellular energy. It involves sequential assembly of ribosomal proteins (RP)s via more than 200 ribogenesis factors. Unlike model organisms where transcription of rRNA and RP genes slows down during stress, in Entamoeba histolytica, pre-rRNA synthesis continues, and unprocessed pre-rRNA accumulates. Northern hybridization from different spacer regions depicted the accumulation of unprocessed intermediates during stress. To gain insight into the vast repertoire of ribosome biogenesis factors and understand the major components playing role during stress we computationally identified ribosome biogenesis factors in E. histolytica. Of the ∼279 Saccharomyces cerevisiae proteins, we could only find 188 proteins in E. histolytica. Some of the proteins missing in E. histolytica were also missing in humans. A number of proteins represented by multiple genes in S. cerevisiae had a single copy in E. histolytica. Interestingly E. histolytica lacked mitochondrial ribosome biogenesis factors and had far less RNase components compared to S. cerevisiae. Transcriptomic studies revealed the differential regulation of ribosomal factors both in serum starved and RRP6 down-regulation conditions. These included the NEP1 and TSR3 proteins that chemically modify 18S-rRNA. Pre-rRNA precursors accumulate upon downregulation of the latter proteins in S. cerevisiae and humans. These data reveal the major factors that regulate pre-rRNA processing during stress in E. histolytica and provide the first complete repertoire of ribosome biogenesis factors in this early-branching protist.
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14
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Puno MR, Lima CD. Structural basis for RNA surveillance by the human nuclear exosome targeting (NEXT) complex. Cell 2022; 185:2132-2147.e26. [PMID: 35688134 PMCID: PMC9210550 DOI: 10.1016/j.cell.2022.04.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/04/2022] [Accepted: 04/08/2022] [Indexed: 02/07/2023]
Abstract
RNA quality control relies on co-factors and adaptors to identify and prepare substrates for degradation by ribonucleases such as the 3' to 5' ribonucleolytic RNA exosome. Here, we determined cryogenic electron microscopy structures of human nuclear exosome targeting (NEXT) complexes bound to RNA that reveal mechanistic insights to substrate recognition and early steps that precede RNA handover to the exosome. The structures illuminate ZCCHC8 as a scaffold, mediating homodimerization while embracing the MTR4 helicase and flexibly anchoring RBM7 to the helicase core. All three subunits collaborate to bind the RNA, with RBM7 and ZCCHC8 surveying sequences upstream of the 3' end to facilitate RNA capture by MTR4. ZCCHC8 obscures MTR4 surfaces important for RNA binding and extrusion as well as MPP6-dependent recruitment and docking onto the RNA exosome core, interactions that contribute to RNA surveillance by coordinating RNA capture, translocation, and extrusion from the helicase to the exosome for decay.
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Affiliation(s)
- M Rhyan Puno
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Howard Hughes Medical Institute, 1275 York Avenue, New York, NY 10065, USA.
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15
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Villa T, Porrua O. Pervasive transcription: a controlled risk. FEBS J 2022. [PMID: 35587776 DOI: 10.1111/febs.16530] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/26/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
Transcriptome-wide interrogation of eukaryotic genomes has unveiled the pervasive nature of RNA polymerase II transcription. Virtually, any DNA region with an accessible chromatin structure can be transcribed, resulting in a mass production of noncoding RNAs (ncRNAs) with the potential of interfering with gene expression programs. Budding yeast has proved to be a powerful model organism to understand the mechanisms at play to control pervasive transcription and overcome the risks of hazardous disruption of cellular functions. In this review, we focus on the actors and strategies yeasts employ to govern ncRNA production, and we discuss recent findings highlighting the dangers of losing control over pervasive transcription.
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Affiliation(s)
- Tommaso Villa
- Institut Jacques Monod CNRS, Université de Paris Cité France
| | - Odil Porrua
- Institut Jacques Monod CNRS, Université de Paris Cité France
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16
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Zhao Y, Rai J, Xu C, He H, Li H. Artificial intelligence-assisted cryoEM structure of Bfr2-Lcp5 complex observed in the yeast small subunit processome. Commun Biol 2022; 5:523. [PMID: 35650250 PMCID: PMC9160021 DOI: 10.1038/s42003-022-03500-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Eukaryotic ribosome is maturated through an elaborate process that includes modification, processing and folding of pre-ribosomal RNA (pre-rRNAs) by a series of ribosome assembly intermediates. More than 70 factors participate in the dynamic assembly and disassembly of the small subunit processome (90S) inside nucleolus, leading to the early maturation of small subunit. The 5' domain of the 18S rRNA is the last to be incorporated into the stable 90S prior to the cleavage of pre-rRNA at the A1 site. This step is facilitated by the Kre33-Enp2-Bfr2-Lcp5 protein module with the participation of the DEAD-box protein Dbp4. Though structures of Kre33 and Enp2 have been modeled in previously observed 90S structures, that of Bfr2-Lcp5 complex remains unavailable. Here, we report an AlphaFold-assisted structure determination of the Bfr2-Lcp5 complex captured in a 3.99 Å - 7.24 Å cryoEM structure of 90S isolated from yeast cells depleted of Pih1, a chaperone protein of the 90S core assembly. The structure model is consistent with the protein-protein interaction results and the secondary structures of recombinant Bfr2 and Bfr2-Lcp5 complex obtained by Circular Dichroism. The Bfr2-Lcp5 complex interaction mimics that of exosome factors Rrp6-Rrp47 and acts to regulate 90S transitions.
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Affiliation(s)
- Yu Zhao
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA
| | - Jay Rai
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA
| | - Chong Xu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA
| | - Huan He
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA
| | - Hong Li
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL, 32306, USA.
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
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17
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Gerlach P, Garland W, Lingaraju M, Salerno-Kochan A, Bonneau F, Basquin J, Jensen TH, Conti E. Structure and regulation of the nuclear exosome targeting complex guides RNA substrates to the exosome. Mol Cell 2022; 82:2505-2518.e7. [PMID: 35688157 PMCID: PMC9278407 DOI: 10.1016/j.molcel.2022.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/07/2022] [Accepted: 04/08/2022] [Indexed: 11/30/2022]
Abstract
In mammalian cells, spurious transcription results in a vast repertoire of unproductive non-coding RNAs, whose deleterious accumulation is prevented by rapid decay. The nuclear exosome targeting (NEXT) complex plays a central role in directing non-functional transcripts to exosome-mediated degradation, but the structural and molecular mechanisms remain enigmatic. Here, we elucidated the architecture of the human NEXT complex, showing that it exists as a dimer of MTR4-ZCCHC8-RBM7 heterotrimers. Dimerization preconfigures the major MTR4-binding region of ZCCHC8 and arranges the two MTR4 helicases opposite to each other, with each protomer able to function on many types of RNAs. In the inactive state of the complex, the 3′ end of an RNA substrate is enclosed in the MTR4 helicase channel by a ZCCHC8 C-terminal gatekeeping domain. The architecture of a NEXT-exosome assembly points to the molecular and regulatory mechanisms with which the NEXT complex guides RNA substrates to the exosome. NEXT homodimerizes through two intertwined ZCCHC8 subunits ZCCHC8 binds MTR4 with both constitutive and regulatory interactions Stable MTR4 arch interactions orient the two helicases in opposite directions Regulatory interactions at the MTR4 helicase domain guide RNA to the exosome
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Affiliation(s)
- Piotr Gerlach
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany.
| | - William Garland
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Mahesh Lingaraju
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Anna Salerno-Kochan
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Fabien Bonneau
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany
| | - Jérôme Basquin
- 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, Aarhus University, Aarhus, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Munich, Germany.
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18
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Daniels PW, Hama Soor T, Levicky Q, Hettema EH, Mitchell P. Contribution of domain structure to the function of the yeast DEDD family exoribonuclease and RNase T functional homolog, Rex1. RNA (NEW YORK, N.Y.) 2022; 28:493-507. [PMID: 35082142 PMCID: PMC8925975 DOI: 10.1261/rna.078939.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The 3' exonucleolytic processing of stable RNAs is conserved throughout biology. Yeast strains lacking the exoribonuclease Rex1 are defective in the 3' processing of stable RNAs, including 5S rRNA and tRNA. The equivalent RNA processing steps in Escherichia coli are carried out by RNase T. Rex1 is larger than RNase T, the catalytic DEDD domain being embedded within uncharacterized amino- and carboxy-terminal regions. Here we report that both amino- and carboxy-terminal regions of Rex1 are essential for its function, as shown by genetic analyses and 5S rRNA profiling. Full-length Rex1, but not mutants lacking amino- or carboxy-terminal regions, accurately processed a 3' extended 5S rRNA substrate. Crosslinking analyses showed that both amino- and carboxy-terminal regions of Rex1 directly contact RNA in vivo. Sequence homology searches identified YFE9 in Schizosaccharomyces pombe and SDN5 in Arabidopsis thaliana as closely related proteins to Rex1. In addition to the DEDD domain, these proteins share a domain, referred to as the RYS (Rex1, YFE9 and SDN5) domain, that includes elements of both the amino- and caroxy-terminal flanking regions. We also characterize a nuclear localization signal in the amino-terminal region of Rex1. These studies reveal a novel dual domain structure at the core of Rex1-related ribonucleases, wherein the catalytic DEDD domain and the RYS domain are aligned such that they both contact the bound substrate. The domain organization of Rex1 is distinct from that of other previously characterized DEDD family nucleases and expands the known repertoire of structures for this fundamental family of RNA processing enzymes.
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Affiliation(s)
- Peter W Daniels
- Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Taib Hama Soor
- Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Quentin Levicky
- Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Ewald H Hettema
- Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Phil Mitchell
- Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, United Kingdom
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19
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Lange H, Gagliardi D. Catalytic activities, molecular connections, and biological functions of plant RNA exosome complexes. THE PLANT CELL 2022; 34:967-988. [PMID: 34954803 PMCID: PMC8894942 DOI: 10.1093/plcell/koab310] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/16/2021] [Indexed: 05/08/2023]
Abstract
RNA exosome complexes provide the main 3'-5'-exoribonuclease activities in eukaryotic cells and contribute to the maturation and degradation of virtually all types of RNA. RNA exosomes consist of a conserved core complex that associates with exoribonucleases and with multimeric cofactors that recruit the enzyme to its RNA targets. Despite an overall high level of structural and functional conservation, the enzymatic activities and compositions of exosome complexes and their cofactor modules differ among eukaryotes. This review highlights unique features of plant exosome complexes, such as the phosphorolytic activity of the core complex, and discusses the exosome cofactors that operate in plants and are dedicated to the maturation of ribosomal RNA, the elimination of spurious, misprocessed, and superfluous transcripts, or the removal of mRNAs cleaved by the RNA-induced silencing complex and other mRNAs prone to undergo silencing.
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Affiliation(s)
- Heike Lange
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
- Author for correspondence:
| | - Dominique Gagliardi
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
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20
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Yim MK, Denson JM, Gold MD, Johnson SJ. Purification and characterization of Mtr4 and TRAMP from S. cerevisiae. Methods Enzymol 2022; 673:425-451. [DOI: 10.1016/bs.mie.2022.03.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Sterrett MC, Enyenihi L, Leung SW, Hess L, Strassler SE, Farchi D, Lee RS, Withers ES, Kremsky I, Baker RE, Basrai MA, van Hoof A, Fasken MB, Corbett AH. A budding yeast model for human disease mutations in the EXOSC2 cap subunit of the RNA exosome complex. RNA (NEW YORK, N.Y.) 2021; 27:1046-1067. [PMID: 34162742 PMCID: PMC8370739 DOI: 10.1261/rna.078618.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
RNA exosomopathies, a growing family of diseases, are linked to missense mutations in genes encoding structural subunits of the evolutionarily conserved, 10-subunit exoribonuclease complex, the RNA exosome. This complex consists of a three-subunit cap, a six-subunit, barrel-shaped core, and a catalytic base subunit. While a number of mutations in RNA exosome genes cause pontocerebellar hypoplasia, mutations in the cap subunit gene EXOSC2 cause an apparently distinct clinical presentation that has been defined as a novel syndrome SHRF (short stature, hearing loss, retinitis pigmentosa, and distinctive facies). We generated the first in vivo model of the SHRF pathogenic amino acid substitutions using budding yeast by modeling pathogenic EXOSC2 missense mutations (p.Gly30Val and p.Gly198Asp) in the orthologous S. cerevisiae gene RRP4 The resulting rrp4 mutant cells show defects in cell growth and RNA exosome function. Consistent with altered RNA exosome function, we detect significant transcriptomic changes in both coding and noncoding RNAs in rrp4-G226D cells that model EXOSC2 p.Gly198Asp, suggesting defects in nuclear surveillance. Biochemical and genetic analyses suggest that the Rrp4 G226D variant subunit shows impaired interactions with key RNA exosome cofactors that modulate the function of the complex. These results provide the first in vivo evidence that pathogenic missense mutations present in EXOSC2 impair the function of the RNA exosome. This study also sets the stage to compare exosomopathy models to understand how defects in RNA exosome function underlie distinct pathologies.
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Affiliation(s)
- Maria C Sterrett
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia 30322, USA
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Liz Enyenihi
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Sara W Leung
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Laurie Hess
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Sarah E Strassler
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia 30322, USA
- Department of Biochemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Daniela Farchi
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Richard S Lee
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Elise S Withers
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Isaac Kremsky
- Loma Linda University School of Medicine, Loma Linda, California 92350, USA
| | - Richard E Baker
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Munira A Basrai
- Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Milo B Fasken
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, Georgia 30322, USA
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22
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Machado de Amorim A, Chakrabarti S. Assembly of multicomponent machines in RNA metabolism: A common theme in mRNA decay pathways. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1684. [PMID: 34351053 DOI: 10.1002/wrna.1684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/05/2022]
Abstract
Multicomponent protein-RNA complexes comprising a ribonuclease and partner RNA helicase facilitate the turnover of mRNA in all domains of life. While these higher-order complexes provide an effective means of physically and functionally coupling the processes of RNA remodeling and decay, most ribonucleases and RNA helicases do not exhibit sequence specificity in RNA binding. This raises the question as to how these assemblies select substrates for processing and how the activities are orchestrated at the precise moment to ensure efficient decay. The answers to these apparent puzzles lie in the auxiliary components of the assemblies that might relay decay-triggering signals. Given their function within the assemblies, these components may be viewed as "sensors." The functions and mechanisms of action of the sensor components in various degradation complexes in bacteria and eukaryotes are highlighted here to discuss their roles in RNA decay processes. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
| | - Sutapa Chakrabarti
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
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23
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Bagatelli FFM, de Luna Vitorino FN, da Cunha JPC, Oliveira CC. The ribosome assembly factor Nop53 has a structural role in the formation of nuclear pre-60S intermediates, affecting late maturation events. Nucleic Acids Res 2021; 49:7053-7074. [PMID: 34125911 PMCID: PMC8266606 DOI: 10.1093/nar/gkab494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic ribosome biogenesis is an elaborate process during which ribosomal proteins assemble with the pre-rRNA while it is being processed and folded. Hundreds of assembly factors (AF) are required and transiently recruited to assist the sequential remodeling events. One of the most intricate ones is the stepwise removal of the internal transcribed spacer 2 (ITS2), between the 5.8S and 25S rRNAs, that constitutes together with five AFs the pre-60S ‘foot’. In the transition from nucleolus to nucleoplasm, Nop53 replaces Erb1 at the basis of the foot and recruits the RNA exosome for the ITS2 cleavage and foot disassembly. Here we comprehensively analyze the impact of Nop53 recruitment on the pre-60S compositional changes. We show that depletion of Nop53, different from nop53 mutants lacking the exosome-interacting motif, not only causes retention of the unprocessed foot in late pre-60S intermediates but also affects the transition from nucleolar state E particle to subsequent nuclear stages. Additionally, we reveal that Nop53 depletion causes the impairment of late maturation events such as Yvh1 recruitment. In light of recently described pre-60S cryo-EM structures, our results provide biochemical evidence for the structural role of Nop53 rearranging and stabilizing the foot interface to assist the Nog2 particle formation.
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Affiliation(s)
- Felipe F M Bagatelli
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP 05508-000, Brazil
| | - Francisca N de Luna Vitorino
- Laboratory of Cell Cycle, Butantan Institute, São Paulo, SP 05503-900, Brazil.,Center of Toxins, Immune-Response and Cell Signaling, Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Julia P C da Cunha
- Laboratory of Cell Cycle, Butantan Institute, São Paulo, SP 05503-900, Brazil.,Center of Toxins, Immune-Response and Cell Signaling, Butantan Institute, São Paulo, SP 05503-900, Brazil
| | - Carla C Oliveira
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP 05508-000, Brazil
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24
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The zinc-finger protein Red1 orchestrates MTREC submodules and binds the Mtl1 helicase arch domain. Nat Commun 2021; 12:3456. [PMID: 34103492 PMCID: PMC8187409 DOI: 10.1038/s41467-021-23565-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/05/2021] [Indexed: 12/02/2022] Open
Abstract
Cryptic unstable transcripts (CUTs) are rapidly degraded by the nuclear exosome in a process requiring the RNA helicase Mtr4 and specific adaptor complexes for RNA substrate recognition. The PAXT and MTREC complexes have recently been identified as homologous exosome adaptors in human and fission yeast, respectively. The eleven-subunit MTREC comprises the zinc-finger protein Red1 and the Mtr4 homologue Mtl1. Here, we use yeast two-hybrid and pull-down assays to derive a detailed interaction map. We show that Red1 bridges MTREC submodules and serves as the central scaffold. In the crystal structure of a minimal Mtl1/Red1 complex an unstructured region adjacent to the Red1 zinc-finger domain binds to both the Mtl1 KOW domain and stalk helices. This interaction extends the canonical interface seen in Mtr4-adaptor complexes. In vivo mutational analysis shows that this interface is essential for cell survival. Our results add to Mtr4 versatility and provide mechanistic insights into the MTREC complex. The human PAXT complex and the MTREC complex in fission yeast are important exosome cofactors, serving in the degradation of specific noncoding RNAs. Here, the authors combine structural, biochemical and in vivo methods to show how Red1 recruits the Mtl1 helicase by an interface not seen before in helicase-adaptor complexes.
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25
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Wang C, Liu Y, DeMario SM, Mandric I, Gonzalez-Figueroa C, Chanfreau GF. Rrp6 Moonlights in an RNA Exosome-Independent Manner to Promote Cell Survival and Gene Expression during Stress. Cell Rep 2021; 31:107754. [PMID: 32521279 PMCID: PMC7587046 DOI: 10.1016/j.celrep.2020.107754] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 11/21/2019] [Accepted: 05/19/2020] [Indexed: 12/13/2022] Open
Abstract
The nuclear RNA exosome is essential for RNA processing and degradation. Here, we show that the exosome nuclear-specific subunit Rrp6p promotes cell survival during heat stress through the cell wall integrity (CWI) pathway, independently of its catalytic activity or association with the core exosome. Rrp6p exhibits negative genetic interactions with the Slt2/Mpk1p or Paf1p elongation factors required for expression of CWI genes during stress. Overexpression of Rrp6p or of its catalytically inactive or exosome-independent mutants can partially rescue the growth defect of the mpk1Δ mutant and stimulates expression of the Mpk1 p target gene FKS2. The rrp6Δ and mpk1Δ mutants show similarities in deficient expression of CWI genes during heat shock, and overexpression of the CWI gene HSP150 can rescue the stress-induced lethality of the mpk1Δrp6Δ mutant. These results demonstrate that Rrp6p moonlights independently from the exosome to ensure proper expression of CWI genes and to promote cell survival during stress. Wang et al. show that Rrp6 functions with the Slt2/Mpk1 and Paf1 elongation factors for the proper expression of CWI genes during heat stress. The role of Rrp6p in promoting heat-stress-induced gene expression does not require Rrp6 catalytic activity or interaction with the nuclear RNA exosome.
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Affiliation(s)
- Charles Wang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yanru Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Samuel M DeMario
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Igor Mandric
- Department of Computer Science, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Carlos Gonzalez-Figueroa
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Guillaume F Chanfreau
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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26
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Das M, Zattas D, Zinder JC, Wasmuth EV, Henri J, Lima CD. Substrate discrimination and quality control require each catalytic activity of TRAMP and the nuclear RNA exosome. Proc Natl Acad Sci U S A 2021; 118:e2024846118. [PMID: 33782132 PMCID: PMC8040639 DOI: 10.1073/pnas.2024846118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quality control requires discrimination between functional and aberrant species to selectively target aberrant substrates for destruction. Nuclear RNA quality control in Saccharomyces cerevisiae includes the TRAMP complex that marks RNA for decay via polyadenylation followed by helicase-dependent 3' to 5' degradation by the RNA exosome. Using reconstitution biochemistry, we show that polyadenylation and helicase activities of TRAMP cooperate with processive and distributive exoribonuclease activities of the nuclear RNA exosome to protect stable RNA from degradation while selectively targeting and degrading less stable RNA. Substrate discrimination is lost when the distributive exoribonuclease activity of Rrp6 is inactivated, leading to degradation of stable and unstable RNA species. These data support a proofreading mechanism in which deadenylation by Rrp6 competes with Mtr4-dependent degradation to protect stable RNA while selectively targeting and degrading unstable RNA.
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Affiliation(s)
- Mom Das
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Dimitrios Zattas
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - John C Zinder
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Elizabeth V Wasmuth
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Julien Henri
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065;
- HHMI, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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27
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Wu G, Schmid M, Rib L, Polak P, Meola N, Sandelin A, Jensen TH. A Two-Layered Targeting Mechanism Underlies Nuclear RNA Sorting by the Human Exosome. Cell Rep 2021; 30:2387-2401.e5. [PMID: 32075771 DOI: 10.1016/j.celrep.2020.01.068] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/09/2019] [Accepted: 01/22/2020] [Indexed: 12/14/2022] Open
Abstract
Degradation of transcripts in human nuclei is primarily facilitated by the RNA exosome. To obtain substrate specificity, the exosome is aided by adaptors; in the nucleoplasm, those adaptors are the nuclear exosome-targeting (NEXT) complex and the poly(A) (pA) exosome-targeting (PAXT) connection. How these adaptors guide exosome targeting remains enigmatic. Employing high-resolution 3' end sequencing, we demonstrate that NEXT substrates arise from heterogenous and predominantly pA- 3' ends often covering kilobase-wide genomic regions. In contrast, PAXT targets harbor well-defined pA+ 3' ends defined by canonical pA site use. Irrespective of this clear division, NEXT and PAXT act redundantly in two ways: (1) regional redundancy, where the majority of exosome-targeted transcription units produce NEXT- and PAXT-sensitive RNA isoforms, and (2) isoform redundancy, where the PAXT connection ensures fail-safe decay of post-transcriptionally polyadenylated NEXT targets. In conjunction, this provides a two-layered targeting mechanism for efficient nuclear sorting of the human transcriptome.
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Affiliation(s)
- Guifen Wu
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Leonor Rib
- The Bioinformatics Centre, Department of Biology and Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaloes Vej 5, 2200 Copenhagen, Denmark
| | - Patrik Polak
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Nicola Meola
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Albin Sandelin
- The Bioinformatics Centre, Department of Biology and Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaloes Vej 5, 2200 Copenhagen, 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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28
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Stuparević I, Novačić A, Rahmouni AR, Fernandez A, Lamb N, Primig M. Regulation of the conserved 3'-5' exoribonuclease EXOSC10/Rrp6 during cell division, development and cancer. Biol Rev Camb Philos Soc 2021; 96:1092-1113. [PMID: 33599082 DOI: 10.1111/brv.12693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 01/31/2023]
Abstract
The conserved 3'-5' exoribonuclease EXOSC10/Rrp6 processes and degrades RNA, regulates gene expression and participates in DNA double-strand break repair and control of telomere maintenance via degradation of the telomerase RNA component. EXOSC10/Rrp6 is part of the multimeric nuclear RNA exosome and interacts with numerous proteins. Previous clinical, genetic, biochemical and genomic studies revealed the protein's essential functions in cell division and differentiation, its RNA substrates and its relevance to autoimmune disorders and oncology. However, little is known about the regulatory mechanisms that control the transcription, translation and stability of EXOSC10/Rrp6 during cell growth, development and disease and how these mechanisms evolved from yeast to human. Herein, we provide an overview of the RNA- and protein expression profiles of EXOSC10/Rrp6 during cell division, development and nutritional stress, and we summarize interaction networks and post-translational modifications across species. Additionally, we discuss how known and predicted protein interactions and post-translational modifications influence the stability of EXOSC10/Rrp6. Finally, we explore the idea that different EXOSC10/Rrp6 alleles, which potentially alter cellular protein levels or affect protein function, might influence human development and disease progression. In this review we interpret information from the literature together with genomic data from knowledgebases to inspire future work on the regulation of this essential protein's stability in normal and malignant cells.
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Affiliation(s)
- Igor Stuparević
- Laboratory of Biochemistry, Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, 10000, Croatia
| | - Ana Novačić
- Laboratory of Biochemistry, Department of Chemistry and Biochemistry, Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, 10000, Croatia
| | - A Rachid Rahmouni
- Centre de Biophysique Moléculaire, UPR4301 du CNRS, Orléans, 45071, France
| | - Anne Fernandez
- Institut de Génétique Humaine, UMR 9002 CNRS, Montpellier, France
| | - Ned Lamb
- Institut de Génétique Humaine, UMR 9002 CNRS, Montpellier, France
| | - Michael Primig
- Univ Rennes, Inserm, EHESP, Irset (Institut de recherche en santé, environnement et travail) - UMR_S 1085, Rennes, 35000, France
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29
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Olsen KJ, Johnson SJ. Mtr4 RNA helicase structures and interactions. Biol Chem 2021; 402:605-616. [PMID: 33857361 DOI: 10.1515/hsz-2020-0329] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 12/10/2020] [Indexed: 01/19/2023]
Abstract
Mtr4 is a Ski2-like RNA helicase that plays a central role in RNA surveillance and degradation pathways as an activator of the RNA exosome. Multiple crystallographic and cryo-EM studies over the past 10 years have revealed important insight into the Mtr4 structure and interactions with protein and nucleic acid binding partners. These structures place Mtr4 at the center of a dynamic process that recruits RNA substrates and presents them to the exosome. In this review, we summarize the available Mtr4 structures and highlight gaps in our current understanding.
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Affiliation(s)
- Keith J Olsen
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT84322-0300, USA
| | - Sean J Johnson
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT84322-0300, USA
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30
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Fraga de Andrade I, Mehta C, Bresnick EH. Post-transcriptional control of cellular differentiation by the RNA exosome complex. Nucleic Acids Res 2020; 48:11913-11928. [PMID: 33119769 PMCID: PMC7708067 DOI: 10.1093/nar/gkaa883] [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: 08/27/2020] [Revised: 09/21/2020] [Accepted: 09/30/2020] [Indexed: 12/12/2022] Open
Abstract
Given the complexity of intracellular RNA ensembles and vast phenotypic remodeling intrinsic to cellular differentiation, it is instructive to consider the role of RNA regulatory machinery in controlling differentiation. Dynamic post-transcriptional regulation of protein-coding and non-coding transcripts is vital for establishing and maintaining proteomes that enable or oppose differentiation. By contrast to extensively studied transcriptional mechanisms governing differentiation, many questions remain unanswered regarding the involvement of post-transcriptional mechanisms. Through its catalytic activity to selectively process or degrade RNAs, the RNA exosome complex dictates the levels of RNAs comprising multiple RNA classes, thereby regulating chromatin structure, gene expression and differentiation. Although the RNA exosome would be expected to control diverse biological processes, studies to elucidate its biological functions and how it integrates into, or functions in parallel with, cell type-specific transcriptional mechanisms are in their infancy. Mechanistic analyses have demonstrated that the RNA exosome confers expression of a differentiation regulatory receptor tyrosine kinase, downregulates the telomerase RNA component TERC, confers genomic stability and promotes DNA repair, which have considerable physiological and pathological implications. In this review, we address how a broadly operational RNA regulatory complex interfaces with cell type-specific machinery to control cellular differentiation.
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Affiliation(s)
- Isabela Fraga de Andrade
- Wisconsin Blood Cancer Research Institute, Department of Cell and Regenerative Biology, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, 1111 Highland Avenue, 4009 WIMR, Madison, WI 53705, USA
| | - Charu Mehta
- Wisconsin Blood Cancer Research Institute, Department of Cell and Regenerative Biology, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, 1111 Highland Avenue, 4009 WIMR, Madison, WI 53705, USA
| | - Emery H Bresnick
- Wisconsin Blood Cancer Research Institute, Department of Cell and Regenerative Biology, Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, 1111 Highland Avenue, 4009 WIMR, Madison, WI 53705, USA
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31
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Weick EM, Lima CD. RNA helicases are hubs that orchestrate exosome-dependent 3'-5' decay. Curr Opin Struct Biol 2020; 67:86-94. [PMID: 33147539 DOI: 10.1016/j.sbi.2020.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/14/2020] [Accepted: 09/20/2020] [Indexed: 01/10/2023]
Abstract
The RNA exosome is a conserved complex of proteins that mediates 3'-5' RNA processing and decay. Its functions range from processing of non-coding RNAs such as ribosomal RNAs and decay of aberrant transcripts in the nucleus to cytoplasmic mRNA turnover and quality control. Ski2-like RNA helicases translocate substrates to exosome-associated ribonucleases and interact with the RNA exosome either directly or as part of multi-subunit helicase-containing complexes that identify and target RNA substrates for decay. Recent structures of these helicases with their RNA-binding partners or the RNA exosome have advanced our understanding of a system of modular and mutually exclusive contacts between the exosome and exosome-associated helicase complexes that shape the transcriptome by orchestrating exosome-dependent 3'-5' decay.
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Affiliation(s)
- Eva-Maria Weick
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Howard Hughes Medical Institute, 1275 York Avenue, New York, NY 10065, USA.
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32
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Kilchert C, Kecman T, Priest E, Hester S, Aydin E, Kus K, Rossbach O, Castello A, Mohammed S, Vasiljeva L. System-wide analyses of the fission yeast poly(A) + RNA interactome reveal insights into organization and function of RNA-protein complexes. Genome Res 2020; 30:1012-1026. [PMID: 32554781 PMCID: PMC7397868 DOI: 10.1101/gr.257006.119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 05/18/2020] [Indexed: 01/12/2023]
Abstract
Large RNA-binding complexes play a central role in gene expression and orchestrate production, function, and turnover of mRNAs. The accuracy and dynamics of RNA–protein interactions within these molecular machines are essential for their function and are mediated by RNA-binding proteins (RBPs). Here, we show that fission yeast whole-cell poly(A)+ RNA–protein crosslinking data provide information on the organization of RNA–protein complexes. To evaluate the relative enrichment of cellular RBPs on poly(A)+ RNA, we combine poly(A)+ RNA interactome capture with a whole-cell extract normalization procedure. This approach yields estimates of in vivo RNA-binding activities that identify subunits within multiprotein complexes that directly contact RNA. As validation, we trace RNA interactions of different functional modules of the 3′ end processing machinery and reveal additional contacts. Extending our analysis to different mutants of the RNA exosome complex, we explore how substrate channeling through the complex is affected by mutation. Our data highlight the central role of the RNA helicase Mtl1 in regulation of the complex and provide insights into how different components contribute to engagement of the complex with substrate RNA. In addition, we characterize RNA-binding activities of novel RBPs that have been recurrently detected in the RNA interactomes of multiple species. We find that many of these, including cyclophilins and thioredoxins, are substoichiometric RNA interactors in vivo. Because RBPomes show very good overall agreement between species, we propose that the RNA-binding characteristics we observe in fission yeast are likely to apply to related proteins in higher eukaryotes as well.
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Affiliation(s)
- Cornelia Kilchert
- Institut für Biochemie, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
| | - Tea Kecman
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Emily Priest
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Svenja Hester
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Ebru Aydin
- Institut für Biochemie, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
| | - Krzysztof Kus
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Oliver Rossbach
- Institut für Biochemie, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
| | - Alfredo Castello
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Shabaz Mohammed
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom.,Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, OX1 3TA, United Kingdom
| | - Lidia Vasiljeva
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
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33
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Lingaraju M, Schuller JM, Falk S, Gerlach P, Bonneau F, Basquin J, Benda C, Conti E. To Process or to Decay: A Mechanistic View of the Nuclear RNA Exosome. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:155-163. [PMID: 32493762 DOI: 10.1101/sqb.2019.84.040295] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The RNA exosome was originally discovered in yeast as an RNA-processing complex required for the maturation of 5.8S ribosomal RNA (rRNA), one of the constituents of the large ribosomal subunit. The exosome is now known in eukaryotes as the major 3'-5' RNA degradation machine involved in numerous processing, turnover, and surveillance pathways, both in the nucleus and the cytoplasm. Yet its role in maturing the 5.8S rRNA in the pre-60S ribosomal particle remains probably the most intricate and emblematic among its functions, as it involves all the RNA unwinding, degradation, and trimming activities embedded in this macromolecular complex. Here, we propose a comprehensive mechanistic model, based on current biochemical and structural data, explaining the dual functions of the nuclear exosome-the constructive versus the destructive mode.
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Affiliation(s)
- Mahesh Lingaraju
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Jan M Schuller
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Sebastian Falk
- Max Perutz Labs, Department of Structural and Computational Biology, University of Vienna, 1030, Vienna, Austria
| | - Piotr Gerlach
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Fabien Bonneau
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Jérôme Basquin
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Christian Benda
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
| | - Elena Conti
- Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, D-82152 Martinsried/Munich, Germany
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34
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Porrua O. Purification and In Vitro Analysis of the Exosome Cofactors Nrd1-Nab3 and Trf4-Air2. Methods Mol Biol 2020; 2062:277-289. [PMID: 31768982 DOI: 10.1007/978-1-4939-9822-7_14] [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] [Indexed: 06/10/2023]
Abstract
In many eukaryotic organisms from yeast to human, the exosome plays an important role in the control of pervasive transcription and in non-coding RNA (ncRNA) processing and quality control by trimming precursor RNAs and degrading aberrant transcripts. In Saccharomyces cerevisiae this function is enabled by the interaction of the exosome with several cofactors: the Nrd1-Nab3 heterodimer and the Trf4-Air2-Mtr4 (TRAMP4) complex. Nrd1 and Nab3 are RNA binding proteins that recognize specific motifs enriched in the target ncRNAs, whereas TRAMP4 adds polyA tails at the 3' end of transcripts and stimulates RNA degradation by the exosome. This chapter provides protocols for the purification of recombinant forms of these exosome cofactors and for the in vitro assessment of their activity.
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Affiliation(s)
- Odil Porrua
- Institut Jacques Monod-UMR7592, CNRS, Université de Paris, Paris, France.
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35
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Keidel A, Conti E, Falk S. Purification and Reconstitution of the S. cerevisiae TRAMP and Ski Complexes for Biochemical and Structural Studies. Methods Mol Biol 2020; 2062:491-513. [PMID: 31768992 DOI: 10.1007/978-1-4939-9822-7_24] [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] [Indexed: 06/10/2023]
Abstract
The RNA exosome is a macromolecular machine that degrades a large variety of RNAs from their 3'-end. It comprises the major 3'-to-5' exonuclease in the cell, completely degrades erroneous and overly abundant RNAs, and is also involved in the precise processing of RNAs. To degrade transcripts both specifically and efficiently the exosome functions together with compartment-specific cofactors. In the yeast S. cerevisiae, the exosome associates with the Ski complex in the cytoplasm and with Mtr4 alone or with Mtr4 as part of the TRAMP complex in the nucleus. Here we describe how to produce, purify, and assemble the Ski and TRAMP complexes from S. cerevisiae.
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Affiliation(s)
- Achim Keidel
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany.
| | - Sebastian Falk
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Martinsried, Germany.
- Max Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Vienna, Austria.
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36
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Abstract
We describe procedures to clone, express, and reconstitute an active human nuclear RNA exosome. Individual recombinant subunits are expressed from E. coli and successfully reconstituted into the nuclear complex, which contains the noncatalytic nine-subunit exosome core, the endoribonuclease and exoribonuclease DIS3, the distributive exoribonuclease EXOSC10, the cofactors C1D and MPP6, and the RNA helicase MTR4.
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Affiliation(s)
- Kurt Januszyk
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Eva-Maria Weick
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Howard Hughes Medical Institute, New York, NY, USA.
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37
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Abstract
The RNA exosome is a ribonucleolytic multiprotein complex that is conserved and essential in all eukaryotes. Although we tend to speak of "the" exosome complex, it should be more correctly viewed as several different subtypes that share a common core. Subtypes of the exosome complex are present in the cytoplasm, the nucleus and the nucleolus of all eukaryotic cells, and carry out the 3'-5' processing and/or degradation of a wide range of RNA substrates.Because the substrate specificity of the exosome complex is determined by cofactors, the system is highly adaptable, and different organisms have adjusted the machinery to their specific needs. Here, we present an overview of exosome complexes and their cofactors that have been described in different eukaryotes.
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Affiliation(s)
- Cornelia Kilchert
- Institut für Biochemie, Justus-Liebig-Universität Gießen, Gießen, Germany.
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38
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Zinder JC, Lima CD. Reconstitution of S. cerevisiae RNA Exosome Complexes Using Recombinantly Expressed Proteins. Methods Mol Biol 2020; 2062:427-448. [PMID: 31768989 PMCID: PMC8596991 DOI: 10.1007/978-1-4939-9822-7_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
3' to 5' RNA degradation is primarily catalyzed by the RNA exosome subunits Dis3 and Rrp6 in the nucleus of Saccharomyces cerevisiae. These enzymes form a complex with the nine-subunit noncatalytic core (Exo9) to carry out their functions in vivo. Protein cofactors Rrp47, Mpp6, and the Mtr4 RNA helicase also assist the complex by modulating its activities and/or recruiting it to specific RNAs for processing or degradation. Here we present our preferred strategy for reconstituting RNA exosomes from S. cerevisiae using purified, recombinantly expressed components.
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Affiliation(s)
- John C Zinder
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Howard Hughes Medical Institute, New York, NY, USA.
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Weick EM, Zinder JC, Lima CD. Strategies for Generating RNA Exosome Complexes from Recombinant Expression Hosts. Methods Mol Biol 2020; 2062:417-425. [PMID: 31768988 PMCID: PMC8565498 DOI: 10.1007/978-1-4939-9822-7_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
The eukaryotic RNA exosome is a conserved and ubiquitous multiprotein complex that possesses multiple RNase activities and is involved in a diverse array of RNA degradation and processing events. While much of our current understanding of RNA exosome function has been elucidated using genetics and cell biology based studies of protein functions, in particular in S. cerevisiae, many important contributions in the field have been enabled through use of in vitro reconstituted complexes. Here, we present an overview of our approach to purify exosome components from recombinant sources and reconstitute them into functional complexes. Three chapters following this overview provide detailed protocols for reconstituting exosome complexes from S. cerevisiae, S. pombe, and H. sapiens. We additionally provide insight on some of the drawbacks of these methods and highlight several important discoveries that have been achieved using reconstituted complexes.
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Affiliation(s)
- Eva-Maria Weick
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - John C Zinder
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Howard Hughes Medical Institute, New York, NY, USA.
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Januszyk K, Lima CD. Reconstitution of the Schizosaccharomyces pombe RNA Exosome. Methods Mol Biol 2020; 2062:449-465. [PMID: 31768990 PMCID: PMC8596990 DOI: 10.1007/978-1-4939-9822-7_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
In this chapter, we describe methods to clone, express, purify, and reconstitute active S. pombe RNA exosomes. Reconstitution procedures are similar to methods that have been successful for the human and budding yeast exosome systems using protein subunits purified from the recombinant host E. coli. By applying these strategies, we can successfully reconstitute the S. pombe noncatalytic exosome core as well as complexes that contain the exoribonucleases Dis3 and Rrp6, cofactors Cti1 (equivalent to budding yeast Rrp47) and Mpp6 as well as the RNA helicase Mtr4.
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Affiliation(s)
- Kurt Januszyk
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Howard Hughes Medical Institute, New York, NY, USA.
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Abstract
The evolutionarily conserved RNA exosome is a multisubunit ribonuclease complex that processes and/or degrades numerous RNAs. Recently, mutations in genes encoding both structural and catalytic subunits of the RNA exosome have been linked to human disease. Mutations in the structural exosome gene EXOSC2 cause a distinct syndrome that includes retinitis pigmentosa, hearing loss, and mild intellectual disability. In contrast, mutations in the structural exosome genes EXOSC3 and EXOSC8 cause pontocerebellar hypoplasia type 1b (PCH1b) and type 1c (PCH1c), respectively, which are related autosomal recessive, neurodegenerative diseases. In addition, mutations in the structural exosome gene EXOSC9 cause a PCH-like disease with cerebellar atrophy and spinal motor neuronopathy. Finally, mutations in the catalytic exosome gene DIS3 have been linked to multiple myeloma, a neoplasm of plasma B cells. How mutations in these RNA exosome genes lead to distinct, tissue-specific diseases is not currently well understood. In this chapter, we examine the role of the RNA exosome complex in human disease and discuss the mechanisms by which mutations in different exosome subunit genes could impair RNA exosome function and give rise to diverse diseases.
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Affiliation(s)
- Milo B Fasken
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
| | - Derrick J Morton
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Emily G Kuiper
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Stephanie K Jones
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA, USA
| | - Sara W Leung
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Anita H Corbett
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
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Abstract
The exoribonuclease Rrp6p is critical for RNA decay in the nucleus. While Rrp6p acts on a large range of diverse substrates, it does not indiscriminately degrade all RNAs. How Rrp6p accomplishes this task is not understood. Here, we measure Rrp6p-RNA binding and degradation kinetics in vitro at single-nucleotide resolution and find an intrinsic substrate selectivity that enables Rrp6p to discriminate against specific RNAs. RNA length and the four 3'-terminal nucleotides contribute most to substrate selectivity and collectively enable Rrp6p to discriminate between different RNAs by several orders of magnitude. The most pronounced discrimination is seen against RNAs ending with CCA-3'. These RNAs correspond to 3' termini of uncharged tRNAs, which are not targeted by Rrp6p in cells. The data show that in contrast to many other proteins that use substrate selectivity to preferentially interact with specific RNAs, Rrp6p utilizes its selectivity to discriminate against specific RNAs. This ability allows Rrp6p to target diverse substrates while avoiding a subset of RNAs.
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Cepeda LPP, Bagatelli FFM, Santos RM, Santos MDM, Nogueira FCS, Oliveira CC. The ribosome assembly factor Nop53 controls association of the RNA exosome with pre-60S particles in yeast. J Biol Chem 2019; 294:19365-19380. [PMID: 31662437 DOI: 10.1074/jbc.ra119.010193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 10/22/2019] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic ribosomal biogenesis is a high-energy-demanding and complex process that requires hundreds of trans-acting factors to dynamically build the highly-organized 40S and 60S subunits. Each ribonucleoprotein complex comprises specific rRNAs and ribosomal proteins that are organized into functional domains. The RNA exosome complex plays a crucial role as one of the pre-60S-processing factors, because it is the RNase responsible for processing the 7S pre-rRNA to the mature 5.8S rRNA. The yeast pre-60S assembly factor Nop53 has previously been shown to associate with the nucleoplasmic pre-60S in a region containing the "foot" structure assembled around the 3' end of the 7S pre-rRNA. Nop53 interacts with 25S rRNA and with several 60S assembly factors, including the RNA exosome, specifically, with its catalytic subunit Rrp6 and with the exosome-associated RNA helicase Mtr4. Nop53 is therefore considered the adaptor responsible for recruiting the exosome complex for 7S processing. Here, using proteomics-based approaches in budding yeast to analyze the effects of Nop53 on the exosome interactome, we found that the exosome binds pre-ribosomal complexes early during the ribosome maturation pathway. We also identified interactions through which Nop53 modulates exosome activity in the context of 60S maturation and provide evidence that in addition to recruiting the exosome, Nop53 may also be important for positioning the exosome during 7S processing. On the basis of these findings, we propose that the exosome is recruited much earlier during ribosome assembly than previously thought, suggesting the existence of additional interactions that remain to be described.
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Affiliation(s)
- Leidy Paola P Cepeda
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, SP, Brazil
| | - Felipe F M Bagatelli
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, SP, Brazil
| | - Renata M Santos
- Proteomics Unit and Laboratory of Proteomics/LADETEC, Federal University of Rio de Janeiro, 22410-001 Rio de Janeiro (RJ), Brazil
| | - Marlon D M Santos
- Laboratory for Structural and Computational Proteomics, Carlos Chagas Institute, Fiocruz, Curitiba, PR, CEP 81350-010, Brazil
| | - Fabio C S Nogueira
- Proteomics Unit and Laboratory of Proteomics/LADETEC, Federal University of Rio de Janeiro, 22410-001 Rio de Janeiro (RJ), Brazil
| | - Carla C Oliveira
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, SP, Brazil
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Das S, Biswas S, Chaudhuri S, Bhattacharyya A, Das B. A Nuclear Zip Code in SKS1 mRNA Promotes Its Slow Export, Nuclear Retention, and Degradation by the Nuclear Exosome/DRN in Saccharomyces cerevisiae. J Mol Biol 2019; 431:3626-3646. [DOI: 10.1016/j.jmb.2019.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 06/26/2019] [Accepted: 07/01/2019] [Indexed: 01/12/2023]
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Pillon MC, Lo YH, Stanley RE. IT'S 2 for the price of 1: Multifaceted ITS2 processing machines in RNA and DNA maintenance. DNA Repair (Amst) 2019; 81:102653. [PMID: 31324529 PMCID: PMC6764878 DOI: 10.1016/j.dnarep.2019.102653] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cells utilize sophisticated RNA processing machines to ensure the quality of RNA. Many RNA processing machines have been further implicated in regulating the DNA damage response signifying a strong link between RNA processing and genome maintenance. One of the most intricate and highly regulated RNA processing pathways is the processing of the precursor ribosomal RNA (pre-rRNA), which is paramount for the production of ribosomes. Removal of the Internal Transcribed Spacer 2 (ITS2), located between the 5.8S and 25S rRNA, is one of the most complex steps of ribosome assembly. Processing of the ITS2 is initiated by the newly discovered endoribonuclease Las1, which cleaves at the C2 site within the ITS2, generating products that are further processed by the polynucleotide kinase Grc3, the 5'→3' exonuclease Rat1, and the 3'→5' RNA exosome complex. In addition to their defined roles in ITS2 processing, these critical cellular machines participate in other stages of ribosome assembly, turnover of numerous cellular RNAs, and genome maintenance. Here we summarize recent work defining the molecular mechanisms of ITS2 processing by these essential RNA processing machines and highlight their emerging roles in transcription termination, heterochromatin function, telomere maintenance, and DNA repair.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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Lingaraju M, Johnsen D, Schlundt A, Langer LM, Basquin J, Sattler M, Heick Jensen T, Falk S, Conti E. The MTR4 helicase recruits nuclear adaptors of the human RNA exosome using distinct arch-interacting motifs. Nat Commun 2019; 10:3393. [PMID: 31358741 PMCID: PMC6662825 DOI: 10.1038/s41467-019-11339-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 07/07/2019] [Indexed: 12/16/2022] Open
Abstract
The nuclear exosome and its essential co-factor, the RNA helicase MTR4, play crucial roles in several RNA degradation pathways. Besides unwinding RNA substrates for exosome-mediated degradation, MTR4 associates with RNA-binding proteins that function as adaptors in different RNA processing and decay pathways. Here, we identify and characterize the interactions of human MTR4 with a ribosome processing adaptor, NVL, and with ZCCHC8, an adaptor involved in the decay of small nuclear RNAs. We show that the unstructured regions of NVL and ZCCHC8 contain short linear motifs that bind the MTR4 arch domain in a mutually exclusive manner. These short sequences diverged from the arch-interacting motif (AIM) of yeast rRNA processing factors. Our results suggest that nuclear exosome adaptors have evolved canonical and non-canonical AIM sequences to target human MTR4 and demonstrate the versatility and specificity with which the MTR4 arch domain can recruit a repertoire of different RNA-binding proteins.
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Affiliation(s)
- Mahesh Lingaraju
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Dennis Johnsen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000, Aarhus C, Denmark
| | - Andreas Schlundt
- Center for Integrated Protein Science Munich (CIPSM) at Department of Chemistry, Technical University of Munich (TUM), 85747, Garching, Germany.,Institute of Structural Biology, Helmholtz-Zentrum München, 85764, Neuherberg, Germany.,Institute for Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ) at Johann Wolfgang Goethe-University, Frankfurt am Main, 60438, Germany
| | - Lukas M Langer
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Jérôme Basquin
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Michael Sattler
- Center for Integrated Protein Science Munich (CIPSM) at Department of Chemistry, Technical University of Munich (TUM), 85747, Garching, Germany.,Institute of Structural Biology, Helmholtz-Zentrum München, 85764, Neuherberg, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000, Aarhus C, Denmark
| | - Sebastian Falk
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany. .,Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
| | - Elena Conti
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
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47
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Moreau K, Le Dantec A, Mosrin-Huaman C, Bigot Y, Piégu B, Rahmouni AR. Perturbation of mRNP biogenesis reveals a dynamic landscape of the Rrp6-dependent surveillance machinery trafficking along the yeast genome. RNA Biol 2019; 16:879-889. [PMID: 31007122 PMCID: PMC6546349 DOI: 10.1080/15476286.2019.1593745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Eukaryotic cells have evolved a nuclear quality control (QC) system to monitor the co-transcriptional mRNA processing and packaging reactions that lead to the formation of export-competent ribonucleoprotein particles (mRNPs). Aberrant mRNPs that fail to pass the QC steps are retained in the nucleus and eliminated by the exonuclease activity of Rrp6. It is still unclear how the surveillance system is precisely coordinated both physically and functionally with the transcription machinery to detect the faulty events that may arise at each step of transcript elongation and mRNP formation. To dissect the QC mechanism, we previously implemented a powerful assay based on global perturbation of mRNP biogenesis in yeast by the bacterial Rho helicase. By monitoring model genes, we have shown that the QC process is coordinated by Nrd1, a component of the NNS complex (Nrd1-Nab3-Sen1) involved in termination, processing and decay of ncRNAs which is recruited by the CTD of RNAP II. Here, we have extended our investigations by analyzing the QC behaviour over the whole yeast genome. We performed high-throughput RNA sequencing (RNA-seq) to survey a large collection of mRNPs whose biogenesis is affected by Rho action and which can be rescued upon Rrp6 depletion. This genome-wide perspective was extended by generating high-resolution binding landscapes (ChIP-seq) of QC components along the yeast chromosomes before and after perturbation of mRNP biogenesis. Our results show that perturbation of mRNP biogenesis redistributes the QC components over the genome with a significant hijacking of Nrd1 and Nab3 from genomic loci producing ncRNAs to Rho-affected protein-coding genes, triggering termination and processing defects of ncRNAs.
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Affiliation(s)
- Kévin Moreau
- a Centre de Biophysique Moléculaire , UPR 4301 du CNRS, Orléans , France
| | - Aurélia Le Dantec
- a Centre de Biophysique Moléculaire , UPR 4301 du CNRS, Orléans , France
| | | | - Yves Bigot
- b Physiologie de la Reproduction et des Comportements , UMR 7247 INRA-CNRS, Nouzilly , France
| | - Benoit Piégu
- b Physiologie de la Reproduction et des Comportements , UMR 7247 INRA-CNRS, Nouzilly , France
| | - A Rachid Rahmouni
- a Centre de Biophysique Moléculaire , UPR 4301 du CNRS, Orléans , France
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Helicase-Dependent RNA Decay Illuminated by a Cryo-EM Structure of a Human Nuclear RNA Exosome-MTR4 Complex. Cell 2019; 173:1663-1677.e21. [PMID: 29906447 DOI: 10.1016/j.cell.2018.05.041] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
Abstract
The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4-containing RNA exosomes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and human and show that they unwind structured substrates to promote degradation. We loaded a human exosome with an optimized DNA-RNA chimera that stalls MTR4 during unwinding and determined its structure to an overall resolution of 3.45 Å by cryoelectron microscopy (cryo-EM). The structure reveals an RNA-engaged helicase atop the non-catalytic core, with RNA captured within the central channel and DIS3 exoribonuclease active site. MPP6 tethers MTR4 to the exosome through contacts to the RecA domains of MTR4. EXOSC10 remains bound to the core, but its catalytic module and cofactor C1D are displaced by RNA-engaged MTR4. Competition for the exosome core may ensure that RNA is committed to degradation by DIS3 when engaged by MTR4.
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Tomita T, Ieguchi K, Takita M, Tsukahara F, Yamada M, Egly JM, Maru Y. C1D is not directly involved in the repair of UV-damaged DNA but protects cells from oxidative stress by regulating gene expressions in human cell lines. J Biochem 2019; 164:415-426. [PMID: 30165670 DOI: 10.1093/jb/mvy069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/24/2018] [Indexed: 11/14/2022] Open
Abstract
A small nuclear protein, C1D, has roles in various cellular processes, transcription regulation, genome stability surveillance, DNA repair and RNA processing, all of which are required to maintain the host life cycles. In the previous report, C1D directly interacts with XPB, a component of the nucleotide excision repair complex, and C1D knockdown reduced cell survival of 27-1 cells, CHO derivative cells, after UV irradiation. To find out the role of C1D in UV-damaged cells, we used human cell lines with siRNA or shRNA to knockdown C1D. C1D knockdown reduced cell survival rates of LU99 and 786-O after UV irradiation, although C1D knockdown did not affect the efficiency of the nucleotide excision repair. Immunostaining data support that C1D is not directly involved in the DNA repair process in UV-damaged cells. However, H2O2 treatment reduced cell viability in LU99 and 786-O cells. We also found that C1D knockdown upregulated DDIT3 expression in LU99 cells and downregulated APEX1 in 786-O cells, suggesting that C1D functions as a co-repressor/activator. The data accounts for the reduction of cell survival rates upon UV irradiation.
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Affiliation(s)
- Takeshi Tomita
- Department of Pharmacology, Tokyo Women's Medical University, 8-1 Kawada, Shinjuku, Tokyo, Japan
| | - Katsuaki Ieguchi
- Department of Pharmacology, Tokyo Women's Medical University, 8-1 Kawada, Shinjuku, Tokyo, Japan
| | - Morichika Takita
- Department of Pharmacology, Tokyo Women's Medical University, 8-1 Kawada, Shinjuku, Tokyo, Japan
| | - Fujiko Tsukahara
- Department of Pharmacology, Tokyo Women's Medical University, 8-1 Kawada, Shinjuku, Tokyo, Japan
| | - Masayuki Yamada
- Center for Medical Education, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, Japan
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire CNRS/INSERM/UdS 1, rue Laurent Fries, BP163 F-67404 Illkirch Cedex, France
| | - Yoshiro Maru
- Department of Pharmacology, Tokyo Women's Medical University, 8-1 Kawada, Shinjuku, Tokyo, Japan
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50
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Schmid M, Jensen TH. The Nuclear RNA Exosome and Its Cofactors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:113-132. [PMID: 31811632 DOI: 10.1007/978-3-030-31434-7_4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The RNA exosome is a highly conserved ribonuclease endowed with 3'-5' exonuclease and endonuclease activities. The multisubunit complex resides in both the nucleus and the cytoplasm, with varying compositions and activities between the two compartments. While the cytoplasmic exosome functions mostly in mRNA quality control pathways, the nuclear RNA exosome partakes in the 3'-end processing and complete decay of a wide variety of substrates, including virtually all types of noncoding (nc) RNAs. To handle these diverse tasks, the nuclear exosome engages with dedicated cofactors, some of which serve as activators by stimulating decay through oligoA addition and/or RNA helicase activities or, as adaptors, by recruiting RNA substrates through their RNA-binding capacities. Most nuclear exosome cofactors contain the essential RNA helicase Mtr4 (MTR4 in humans). However, apart from Mtr4, nuclear exosome cofactors have undergone significant evolutionary divergence. Here, we summarize biochemical and functional knowledge about the nuclear exosome and exemplify its cofactor variety by discussing the best understood model organisms-the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe, and human cells.
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Affiliation(s)
- Manfred Schmid
- 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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