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Köferle A, Schlattl A, Hörmann A, Thatikonda V, Popa A, Spreitzer F, Ravichandran MC, Supper V, Oberndorfer S, Puchner T, Wieshofer C, Corcokovic M, Reiser C, Wöhrle S, Popow J, Pearson M, Martinez J, Weitzer S, Mair B, Neumüller RA. Interrogation of cancer gene dependencies reveals paralog interactions of autosome and sex chromosome-encoded genes. Cell Rep 2022; 39:110636. [PMID: 35417719 DOI: 10.1016/j.celrep.2022.110636] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 12/22/2021] [Accepted: 03/16/2022] [Indexed: 02/07/2023] Open
Abstract
Genetic networks are characterized by extensive buffering. During tumor evolution, disruption of functional redundancies can create de novo vulnerabilities that are specific to cancer cells. Here, we systematically search for cancer-relevant paralog interactions using CRISPR screens and publicly available loss-of-function datasets. Our analysis reveals >2,000 candidate dependencies, several of which we validate experimentally, including CSTF2-CSTF2T, DNAJC15-DNAJC19, FAM50A-FAM50B, and RPP25-RPP25L. We provide evidence that RPP25L can physically and functionally compensate for the absence of RPP25 as a member of the RNase P/MRP complexes in tRNA processing. Our analysis also reveals unexpected redundancies between sex chromosome genes. We show that chrX- and chrY-encoded paralogs, such as ZFX-ZFY, DDX3X-DDX3Y, and EIF1AX-EIF1AY, are functionally linked. Tumor cell lines from male patients with loss of chromosome Y become dependent on the chrX-encoded gene. We propose targeting of chrX-encoded paralogs as a general therapeutic strategy for human tumors that have lost the Y chromosome.
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Affiliation(s)
- Anna Köferle
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Andreas Schlattl
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Alexandra Hörmann
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Venu Thatikonda
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Alexandra Popa
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Fiona Spreitzer
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | | | - Verena Supper
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Sarah Oberndorfer
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Teresa Puchner
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Corinna Wieshofer
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Maja Corcokovic
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Christoph Reiser
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Simon Wöhrle
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Johannes Popow
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Mark Pearson
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria
| | - Barbara Mair
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria.
| | - Ralph A Neumüller
- Boehringer Ingelheim RCV GmbH & Co KG, Doktor-Boehringer-Gasse 5-11, 1120 Vienna, Austria.
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2
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Kroupova A, Ackle F, Asanović I, Weitzer S, Boneberg FM, Faini M, Leitner A, Chui A, Aebersold R, Martinez J, Jinek M. Molecular architecture of the human tRNA ligase complex. eLife 2021; 10:e71656. [PMID: 34854379 PMCID: PMC8668186 DOI: 10.7554/elife.71656] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/01/2021] [Indexed: 01/23/2023] Open
Abstract
RtcB enzymes are RNA ligases that play essential roles in tRNA splicing, unfolded protein response, and RNA repair. In metazoa, RtcB functions as part of a five-subunit tRNA ligase complex (tRNA-LC) along with Ddx1, Cgi-99, Fam98B, and Ashwin. The human tRNA-LC or its individual subunits have been implicated in additional cellular processes including microRNA maturation, viral replication, DNA double-strand break repair, and mRNA transport. Here, we present a biochemical analysis of the inter-subunit interactions within the human tRNA-LC along with crystal structures of the catalytic subunit RTCB and the N-terminal domain of CGI-99. We show that the core of the human tRNA-LC is assembled from RTCB and the C-terminal alpha-helical regions of DDX1, CGI-99, and FAM98B, all of which are required for complex integrity. The N-terminal domain of CGI-99 displays structural homology to calponin-homology domains, and CGI-99 and FAM98B associate via their N-terminal domains to form a stable subcomplex. The crystal structure of GMP-bound RTCB reveals divalent metal coordination geometry in the active site, providing insights into its catalytic mechanism. Collectively, these findings shed light on the molecular architecture and mechanism of the human tRNA ligase complex and provide a structural framework for understanding its functions in cellular RNA metabolism.
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Affiliation(s)
- Alena Kroupova
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Fabian Ackle
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Igor Asanović
- Max Perutz Labs, Vienna BioCenter (VBC)ViennaAustria
| | | | | | - Marco Faini
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | - Alessia Chui
- Department of Biochemistry, University of ZurichZurichSwitzerland
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH ZurichZurichSwitzerland
| | | | - Martin Jinek
- Department of Biochemistry, University of ZurichZurichSwitzerland
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3
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Sekulovski S, Devant P, Panizza S, Gogakos T, Pitiriciu A, Heitmeier K, Ramsay EP, Barth M, Schmidt C, Tuschl T, Baas F, Weitzer S, Martinez J, Trowitzsch S. Assembly defects of human tRNA splicing endonuclease contribute to impaired pre-tRNA processing in pontocerebellar hypoplasia. Nat Commun 2021; 12:5610. [PMID: 34584079 PMCID: PMC8479045 DOI: 10.1038/s41467-021-25870-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/03/2021] [Indexed: 02/07/2023] Open
Abstract
Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1. Splice site recognition involves the mature domain and the anticodon-intron base pair of pre-tRNAs. The 2.1-Å resolution X-ray crystal structure of a TSEN15–34 heterodimer and differential scanning fluorimetry analyses show that PCH mutations cause thermal destabilization. While endonuclease activity in recombinant mutant TSEN is unaltered, we observe assembly defects and reduced pre-tRNA cleavage activity resulting in an imbalanced pre-tRNA pool in PCH patient-derived fibroblasts. Our work defines the molecular principles of intron excision in humans and provides evidence that modulation of TSEN stability may contribute to PCH phenotypes. Mutations within subunits of the tRNA splicing endonuclease complex (TSEN) are associated with pontocerebellar hypoplasia (PCH). Here the authors show that tRNA intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers, and provide evidence that modulation of TSEN stability may contribute to PCH phenotypes.
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Affiliation(s)
- Samoil Sekulovski
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Pascal Devant
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.,Ph.D. Program in Virology, Harvard Medical School, Boston, MA, USA.,Harvard Medical School and Division of Gastroenterology, Boston Children's Hospital, Boston, MA, USA
| | - Silvia Panizza
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Tasos Gogakos
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Anda Pitiriciu
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Katharina Heitmeier
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany
| | | | - Marie Barth
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carla Schmidt
- Interdisciplinary research center HALOmem, Charles Tanford Protein Center, Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Thomas Tuschl
- Laboratory for RNA Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Frank Baas
- Department of Clinical Genetics, Leiden University, Leiden, Netherlands
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Frankfurt/Main, Germany.
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4
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Asanović I, Strandback E, Kroupova A, Pasajlic D, Meinhart A, Tsung-Pin P, Djokovic N, Anrather D, Schuetz T, Suskiewicz MJ, Sillamaa S, Köcher T, Beveridge R, Nikolic K, Schleiffer A, Jinek M, Hartl M, Clausen T, Penninger J, Macheroux P, Weitzer S, Martinez J. The oxidoreductase PYROXD1 uses NAD(P) + as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and unfolded protein response. Mol Cell 2021; 81:2520-2532.e16. [PMID: 33930333 DOI: 10.1016/j.molcel.2021.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/09/2021] [Accepted: 04/09/2021] [Indexed: 12/19/2022]
Abstract
The tRNA ligase complex (tRNA-LC) splices precursor tRNAs (pre-tRNA), and Xbp1-mRNA during the unfolded protein response (UPR). In aerobic conditions, a cysteine residue bound to two metal ions in its ancient, catalytic subunit RTCB could make the tRNA-LC susceptible to oxidative inactivation. Here, we confirm this hypothesis and reveal a co-evolutionary association between the tRNA-LC and PYROXD1, a conserved and essential oxidoreductase. We reveal that PYROXD1 preserves the activity of the mammalian tRNA-LC in pre-tRNA splicing and UPR. PYROXD1 binds the tRNA-LC in the presence of NAD(P)H and converts RTCB-bound NAD(P)H into NAD(P)+, a typical oxidative co-enzyme. However, NAD(P)+ here acts as an antioxidant and protects the tRNA-LC from oxidative inactivation, which is dependent on copper ions. Genetic variants of PYROXD1 that cause human myopathies only partially support tRNA-LC activity. Thus, we establish the tRNA-LC as an oxidation-sensitive metalloenzyme, safeguarded by the flavoprotein PYROXD1 through an unexpected redox mechanism.
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Affiliation(s)
- Igor Asanović
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria
| | - Emilia Strandback
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, 8010 Graz, Austria; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Alena Kroupova
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Djurdja Pasajlic
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria
| | - Anton Meinhart
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Pai Tsung-Pin
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; AnnJi Pharmaceutical, Taipei, Taiwan
| | - Nemanja Djokovic
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Dorothea Anrather
- Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Thomas Schuetz
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Department of Internal Medicine III (Cardiology and Angiology), Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria
| | - Marcin Józef Suskiewicz
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria; Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE Oxford, UK
| | - Sirelin Sillamaa
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Thomas Köcher
- Vienna BioCenter Core Facilities, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Rebecca Beveridge
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria; Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, G1 1XL Glasgow, UK
| | - Katarina Nikolic
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria; Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Markus Hartl
- Max Perutz Labs, University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Tim Clausen
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
| | - Josef Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Department of Medical Genetics, Life Science Institute, University of British Columbia, C201 - 4500 Oak Street, V6H 3N1 Vancouver, BC, Canada
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, 8010 Graz, Austria
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter (VBC), Dr. Bohr-Gasse 9/2, 1030 Vienna, Austria.
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5
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Pinto PH, Kroupova A, Schleiffer A, Mechtler K, Jinek M, Weitzer S, Martinez J. ANGEL2 is a member of the CCR4 family of deadenylases with 2',3'-cyclic phosphatase activity. Science 2020; 369:524-530. [PMID: 32732418 DOI: 10.1126/science.aba9763] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022]
Abstract
RNA molecules are frequently modified with a terminal 2',3'-cyclic phosphate group as a result of endonuclease cleavage, exonuclease trimming, or de novo synthesis. During pre-transfer RNA (tRNA) and unconventional messenger RNA (mRNA) splicing, 2',3'-cyclic phosphates are substrates of the tRNA ligase complex, and their removal is critical for recycling of tRNAs upon ribosome stalling. We identified the predicted deadenylase angel homolog 2 (ANGEL2) as a human phosphatase that converts 2',3'-cyclic phosphates into 2',3'-OH nucleotides. We analyzed ANGEL2's substrate preference, structure, and reaction mechanism. Perturbing ANGEL2 expression affected the efficiency of pre-tRNA processing, X-box-binding protein 1 (XBP1) mRNA splicing during the unfolded protein response, and tRNA nucleotidyltransferase 1 (TRNT1)-mediated CCA addition onto tRNAs. Our results indicate that ANGEL2 is involved in RNA pathways that rely on the ligation or hydrolysis of 2',3'-cyclic phosphates.
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Affiliation(s)
- Paola H Pinto
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter, 1030 Vienna, Austria
| | - Alena Kroupova
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Alexander Schleiffer
- IMP/IMBA Bioinformatics Core Facility, Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology, Vienna BioCenter, 1030 Vienna, Austria.,Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna BioCenter, 1030 Vienna, Austria
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Stefan Weitzer
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter, 1030 Vienna, Austria.
| | - Javier Martinez
- Max Perutz Labs, Medical University of Vienna, Vienna BioCenter, 1030 Vienna, Austria.
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6
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Conde CD, Petronczki ÖY, Baris S, Willmann KL, Girardi E, Salzer E, Weitzer S, Ardy RC, Krolo A, Ijspeert H, Kiykim A, Karakoc-Aydiner E, Förster-Waldl E, Kager L, Pickl WF, Superti-Furga G, Martínez J, Loizou JI, Ozen A, van der Burg M, Boztug K. Polymerase δ deficiency causes syndromic immunodeficiency with replicative stress. J Clin Invest 2020; 129:4194-4206. [PMID: 31449058 DOI: 10.1172/jci128903] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/21/2019] [Indexed: 12/14/2022] Open
Abstract
Polymerase δ is essential for eukaryotic genome duplication and synthesizes DNA at both the leading and lagging strands. The polymerase δ complex is a heterotetramer comprising the catalytic subunit POLD1 and the accessory subunits POLD2, POLD3, and POLD4. Beyond DNA replication, the polymerase δ complex has emerged as a central element in genome maintenance. The essentiality of polymerase δ has constrained the generation of polymerase δ-knockout cell lines or model organisms and, therefore, the understanding of the complexity of its activity and the function of its accessory subunits. To our knowledge, no germline biallelic mutations affecting this complex have been reported in humans. In patients from 2 independent pedigrees, we have identified what we believe to be a novel syndrome with reduced functionality of the polymerase δ complex caused by germline biallelic mutations in POLD1 or POLD2 as the underlying etiology of a previously unknown autosomal-recessive syndrome that combines replicative stress, neurodevelopmental abnormalities, and immunodeficiency. Patients' cells showed impaired cell-cycle progression and replication-associated DNA lesions that were reversible upon overexpression of polymerase δ. The mutations affected the stability and interactions within the polymerase δ complex or its intrinsic polymerase activity. We believe our discovery of human polymerase δ deficiency identifies the central role of this complex in the prevention of replication-related DNA lesions, with particular relevance to adaptive immunity.
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Affiliation(s)
- Cecilia Domínguez Conde
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and
| | - Özlem Yüce Petronczki
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria
| | - Safa Baris
- Pediatric Allergy and Immunology, Marmara University, Faculty of Medicine, Istanbul, Turkey.,Jeffrey Modell Diagnostic Center for Primary Immunodeficiency Diseases, Marmara University, Istanbul, Turkey
| | - Katharina L Willmann
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and
| | - Enrico Girardi
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and
| | - Elisabeth Salzer
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria.,St. Anna Children's Hospital, Department of Pediatrics and Adolescent Medicine, Vienna, Austria
| | - Stefan Weitzer
- Center for Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Rico Chandra Ardy
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria
| | - Ana Krolo
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria
| | - Hanna Ijspeert
- Department of Pediatrics, Laboratory for Immunology, Leiden University Medical Centre, Leiden, Netherlands
| | - Ayca Kiykim
- Pediatric Allergy and Immunology, Marmara University, Faculty of Medicine, Istanbul, Turkey.,Jeffrey Modell Diagnostic Center for Primary Immunodeficiency Diseases, Marmara University, Istanbul, Turkey
| | - Elif Karakoc-Aydiner
- Pediatric Allergy and Immunology, Marmara University, Faculty of Medicine, Istanbul, Turkey.,Jeffrey Modell Diagnostic Center for Primary Immunodeficiency Diseases, Marmara University, Istanbul, Turkey
| | - Elisabeth Förster-Waldl
- Department of Neonatology, Pediatric Intensive Care and Neuropediatrics, Department of Pediatrics and Adolescent Medicine
| | - Leo Kager
- St. Anna Children's Hospital, Department of Pediatrics and Adolescent Medicine, Vienna, Austria
| | - Winfried F Pickl
- Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, and
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Javier Martínez
- Center for Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Joanna I Loizou
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and
| | - Ahmet Ozen
- Pediatric Allergy and Immunology, Marmara University, Faculty of Medicine, Istanbul, Turkey.,Jeffrey Modell Diagnostic Center for Primary Immunodeficiency Diseases, Marmara University, Istanbul, Turkey
| | - Mirjam van der Burg
- Department of Pediatrics, Laboratory for Immunology, Leiden University Medical Centre, Leiden, Netherlands
| | - Kaan Boztug
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases.,CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, and.,St. Anna Children's Cancer Research Institute (CCRI), Vienna, Austria.,St. Anna Children's Hospital, Department of Pediatrics and Adolescent Medicine, Vienna, Austria
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7
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Abstract
The RNA-induced silencing complex (RISC) is the effector complex in the RNA interference (RNAi) pathway. In order to become assembled into RISC, synthetic small interfering RNAs (siRNAs) are phosphorylated at the 5' end upon transfection into cells. The enzymatic activity responsible for this phosphorylation event has so far remained elusive. Using a classical chromatographic approach, we recently identified and characterized hClp1 as the "siRNA-kinase" in HeLa cells. hClp1 is in fact a general RNA-kinase, and a component of the tRNA splicing endonuclease and the mRNA 3' end formation machinery. We discuss the relevance of this finding, and provide further views and perspectives for the analysis of hClp1 in tRNA splicing, mRNA cleavage and polyadenylation and other RNA metabolic processes in which hClp1 might play a role.
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Affiliation(s)
- Stefan Weitzer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.
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8
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Weitzer S, Hanada T, Penninger JM, Martinez J. CLP1 as a novel player in linking tRNA splicing to neurodegenerative disorders. WIREs RNA 2014; 6:47-63. [DOI: 10.1002/wrna.1255] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Stefan Weitzer
- IMBA; Institute of Molecular Biotechnology of the Academy of Sciences; Vienna Austria
| | - Toshikatsu Hanada
- TK Project, Medical Innovation Center; Kyoto University Graduate School of Medicine; Kyoto Japan
| | - Josef M. Penninger
- IMBA; Institute of Molecular Biotechnology of the Academy of Sciences; Vienna Austria
| | - Javier Martinez
- IMBA; Institute of Molecular Biotechnology of the Academy of Sciences; Vienna Austria
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9
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Karaca E, Weitzer S, Pehlivan D, Shiraishi H, Gogakos T, Hanada T, Jhangiani SN, Wiszniewski W, Withers M, Campbell IM, Erdin S, Isikay S, Franco LM, Gonzaga-Jauregui C, Gambin T, Gelowani V, Hunter JV, Yesil G, Koparir E, Yilmaz S, Brown M, Briskin D, Hafner M, Morozov P, Farazi TA, Bernreuther C, Glatzel M, Trattnig S, Friske J, Kronnerwetter C, Bainbridge MN, Gezdirici A, Seven M, Muzny DM, Boerwinkle E, Ozen M, Clausen T, Tuschl T, Yuksel A, Hess A, Gibbs RA, Martinez J, Penninger JM, Lupski JR. Human CLP1 mutations alter tRNA biogenesis, affecting both peripheral and central nervous system function. Cell 2014; 157:636-50. [PMID: 24766809 DOI: 10.1016/j.cell.2014.02.058] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 12/19/2013] [Accepted: 02/21/2014] [Indexed: 10/25/2022]
Abstract
CLP1 is a RNA kinase involved in tRNA splicing. Recently, CLP1 kinase-dead mice were shown to display a neuromuscular disorder with loss of motor neurons and muscle paralysis. Human genome analyses now identified a CLP1 homozygous missense mutation (p.R140H) in five unrelated families, leading to a loss of CLP1 interaction with the tRNA splicing endonuclease (TSEN) complex, largely reduced pre-tRNA cleavage activity, and accumulation of linear tRNA introns. The affected individuals develop severe motor-sensory defects, cortical dysgenesis, and microcephaly. Mice carrying kinase-dead CLP1 also displayed microcephaly and reduced cortical brain volume due to the enhanced cell death of neuronal progenitors that is associated with reduced numbers of cortical neurons. Our data elucidate a neurological syndrome defined by CLP1 mutations that impair tRNA splicing. Reduction of a founder mutation to homozygosity illustrates the importance of rare variations in disease and supports the clan genomics hypothesis.
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Affiliation(s)
- Ender Karaca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stefan Weitzer
- Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hiroshi Shiraishi
- Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Tasos Gogakos
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Toshikatsu Hanada
- Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences, 1030 Vienna, Austria; Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Wojciech Wiszniewski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Marjorie Withers
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ian M Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Serkan Erdin
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Sedat Isikay
- Gaziantep Children's Hospital, Gaziantep 27560, Turkey
| | - Luis M Franco
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Violet Gelowani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill V Hunter
- Department of Pediatric Radiology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Gozde Yesil
- Department of Medical Genetics, Bezmialem University, Istanbul 34093, Turkey
| | - Erkan Koparir
- Department of Medical Genetics, Cerrahpasa Medical School of Istanbul University, Istanbul 34098, Turkey
| | - Sarenur Yilmaz
- Istanbul Medeniyet University, Faculty of Medicine, Department of Medical Genetics, Istanbul 34730, Turkey
| | - Miguel Brown
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Daniel Briskin
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Markus Hafner
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Pavel Morozov
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Thalia A Farazi
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Christian Bernreuther
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - Siegfried Trattnig
- Department of Radiology, MR Center of Excellence, Medical University of Vienna, Vienna 1090, Austria
| | - Joachim Friske
- Department of Radiology, MR Center of Excellence, Medical University of Vienna, Vienna 1090, Austria
| | - Claudia Kronnerwetter
- Department of Radiology, MR Center of Excellence, Medical University of Vienna, Vienna 1090, Austria
| | - Matthew N Bainbridge
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alper Gezdirici
- Department of Medical Genetics, Cerrahpasa Medical School of Istanbul University, Istanbul 34098, Turkey
| | - Mehmet Seven
- Department of Medical Genetics, Cerrahpasa Medical School of Istanbul University, Istanbul 34098, Turkey
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric Boerwinkle
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Human Genetics Center, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Mustafa Ozen
- Department of Medical Genetics, Cerrahpasa Medical School of Istanbul University, Istanbul 34098, Turkey
| | | | - Tim Clausen
- Institute of Molecular Pathology (IMP), 1030 Vienna, Austria
| | - Thomas Tuschl
- Howard Hughes Medical Institute, Laboratory of RNA Molecular Biology, Rockefeller University, New York, NY 10065, USA
| | - Adnan Yuksel
- Department of Medical Genetics, Cerrahpasa Medical School of Istanbul University, Istanbul 34098, Turkey
| | - Andreas Hess
- Institute for Experimental Pharmacology, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany; Campus Support Facility (CSF), Vienna BioCentre, Vienna 1030, Austria
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Javier Martinez
- Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences, 1030 Vienna, Austria.
| | - Josef M Penninger
- Institute of Molecular Biotechnology (IMBA) of the Austrian Academy of Sciences, 1030 Vienna, Austria.
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
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10
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Hanada T, Weitzer S, Mair B, Bernreuther C, Wainger BJ, Ichida J, Hanada R, Orthofer M, Cronin SJ, Komnenovic V, Minis A, Sato F, Mimata H, Yoshimura A, Tamir I, Rainer J, Kofler R, Yaron A, Eggan KC, Woolf CJ, Glatzel M, Herbst R, Martinez J, Penninger JM. CLP1 links tRNA metabolism to progressive motor-neuron loss. Nature 2013; 495:474-80. [PMID: 23474986 DOI: 10.1038/nature11923] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 01/18/2013] [Indexed: 12/21/2022]
Abstract
CLP1 was the first mammalian RNA kinase to be identified. However, determining its in vivo function has been elusive. Here we generated kinase-dead Clp1 (Clp1(K/K)) mice that show a progressive loss of spinal motor neurons associated with axonal degeneration in the peripheral nerves and denervation of neuromuscular junctions, resulting in impaired motor function, muscle weakness, paralysis and fatal respiratory failure. Transgenic rescue experiments show that CLP1 functions in motor neurons. Mechanistically, loss of CLP1 activity results in accumulation of a novel set of small RNA fragments, derived from aberrant processing of tyrosine pre-transfer RNA. These tRNA fragments sensitize cells to oxidative-stress-induced p53 (also known as TRP53) activation and p53-dependent cell death. Genetic inactivation of p53 rescues Clp1(K/K) mice from the motor neuron loss, muscle denervation and respiratory failure. Our experiments uncover a mechanistic link between tRNA processing, formation of a new RNA species and progressive loss of lower motor neurons regulated by p53.
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Affiliation(s)
- Toshikatsu Hanada
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria
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11
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Popow J, Englert M, Weitzer S, Schleiffer A, Mierzwa B, Mechtler K, Trowitzsch S, Will CL, Lührmann R, Söll D, Martinez J. HSPC117 is the essential subunit of a human tRNA splicing ligase complex. Science 2011; 331:760-4. [PMID: 21311021 DOI: 10.1126/science.1197847] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Splicing of mammalian precursor transfer RNA (tRNA) molecules involves two enzymatic steps. First, intron removal by the tRNA splicing endonuclease generates separate 5' and 3' exons. In animals, the second step predominantly entails direct exon ligation by an elusive RNA ligase. Using activity-guided purification of tRNA ligase from HeLa cell extracts, we identified HSPC117, a member of the UPF0027 (RtcB) family, as the essential subunit of a tRNA ligase complex. RNA interference-mediated depletion of HSPC117 inhibited maturation of intron-containing pre-tRNA both in vitro and in living cells. The high sequence conservation of HSPC117/RtcB proteins is suggestive of RNA ligase roles of this protein family in various organisms.
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Affiliation(s)
- Johannes Popow
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), A-1030 Vienna, Austria
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12
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Karayel E, Bürckstümmer T, Bilban M, Dürnberger G, Weitzer S, Martinez J, Superti-Furga G. The TLR-independent DNA recognition pathway in murine macrophages: Ligand features and molecular signature. Cytokine 2009. [DOI: 10.1016/j.cyto.2009.07.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Karayel E, Bürckstümmer T, Bilban M, Dürnberger G, Weitzer S, Martinez J, Superti-Furga G. The TLR-independent DNA recognition pathway in murine macrophages: Ligand features and molecular signature. Eur J Immunol 2009; 39:1929-36. [PMID: 19551900 DOI: 10.1002/eji.200939344] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recognition of foreign DNA by cytosolic innate immune receptors triggers the production of IFN-beta. However, it is unclear whether different types of DNA ligands are recognized by similar receptors and whether the resulting response is distinct from the endosomal TLR response. To address these questions, we compared the two most commonly used types of DNA ligands (IFN-stimulatory DNA (ISD) and poly(dAdT)) and assessed the minimal structural requirements for stimulatory capacity in RAW264.7 cells. Gene expression signatures and competition experiments suggest that ISD and poly(dAdT) are qualitatively indistinguishable and differ from the CpG-containing oligonucleotides triggering the TLR9 pathway. Structure - activity relationship analyses revealed that a minimal length of two helical turns is sufficient for ISD-mediated IFN-beta induction, while phosphorylation at the 5'-end is dispensable. Altogether, our data suggest that, in murine macrophages, only one major cytosolic DNA recognition pathway is operational.
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Affiliation(s)
- Evren Karayel
- Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
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14
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Mc Intyre J, Muller EGD, Weitzer S, Snydsman BE, Davis TN, Uhlmann F. In vivo analysis of cohesin architecture using FRET in the budding yeast Saccharomyces cerevisiae. EMBO J 2007; 26:3783-93. [PMID: 17660750 PMCID: PMC1952217 DOI: 10.1038/sj.emboj.7601793] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2007] [Accepted: 06/18/2007] [Indexed: 12/23/2022] Open
Abstract
Cohesion between sister chromatids in eukaryotes is mediated by the evolutionarily conserved cohesin complex. Cohesin forms a proteinaceous ring, large enough to trap pairs of replicated sister chromatids. The circumference consists of the Smc1 and Smc3 subunits, while Scc1 is thought to close the ring by bridging the Smc (structural maintenance of chromosomes) ATPase head domains. Little is known about two additional subunits, Scc3 and Pds5, and about possible conformational changes of the complex during the cell cycle. We have employed fluorescence resonance energy transfer (FRET) to analyse interactions within the cohesin complex in live budding yeast. These experiments reveal an unexpected geometry of Scc1 at the Smc heads, and suggest that Pds5 plays a role at the Smc hinge on the opposite side of the ring. Key subunit interactions, including close proximity of the two ATPase heads, are constitutive throughout the cell cycle. This depicts cohesin as a stable molecular machine undergoing only transient conformational changes during binding and dissociation from chromosomes. Using FRET, we did not observe interactions between more than one cohesin complex in vivo.
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Affiliation(s)
- John Mc Intyre
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, UK
| | - Eric G D Muller
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Stefan Weitzer
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, UK
| | - Brian E Snydsman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, London, UK
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15
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Weitzer S, Martinez J. The human RNA kinase hClp1 is active on 3' transfer RNA exons and short interfering RNAs. Nature 2007; 447:222-6. [PMID: 17495927 DOI: 10.1038/nature05777] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Accepted: 03/21/2007] [Indexed: 11/09/2022]
Abstract
RNA interference allows the analysis of gene function by introducing synthetic, short interfering RNAs (siRNAs) into cells. In contrast to siRNA and microRNA duplexes generated endogenously by the RNaseIII endonuclease Dicer, synthetic siRNAs display a 5' OH group. However, to become incorporated into the RNA-induced silencing complex (RISC) and mediate target RNA cleavage, the guide strand of an siRNA needs to display a phosphate group at the 5' end. The identity of the responsible kinase has so far remained elusive. Monitoring siRNA phosphorylation, we applied a chromatographic approach that resulted in the identification of the protein hClp1 (human Clp1), a known component of both transfer RNA splicing and messenger RNA 3'-end formation machineries. Here we report that the kinase hClp1 phosphorylates and licenses synthetic siRNAs to become assembled into RISC for subsequent target RNA cleavage. More importantly, we reveal the physiological role of hClp1 as the RNA kinase that phosphorylates the 5' end of the 3' exon during human tRNA splicing, allowing the subsequent ligation of both exon halves by an unknown tRNA ligase. The investigation of this novel enzymatic activity of hClp1 in the context of mRNA 3'-end formation, where no RNA phosphorylation event has hitherto been predicted, remains a challenge for the future.
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Affiliation(s)
- Stefan Weitzer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr Gasse 3, A-1030 Vienna, Austria
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16
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Abstract
BACKGROUND Cohesion between sister chromatids is promoted by the chromosomal cohesin complex that forms a proteinaceous ring, large enough in principle to embrace two sister strands. The mechanism by which cohesin binds to DNA, and how sister chromatid cohesion is established, is unknown. RESULTS Biochemical studies of cohesin have largely been limited to protein isolated from soluble cellular fractions. Here, we characterize cohesin purified from budding yeast chromatin, suggesting that chromosomal cohesin is sufficiently described by its known distinctive ring structure. We present evidence that the two Smc subunits of cohesin by themselves form a ring, closed at interacting ATPase head domains. A motif in the Smc1 subunit implicated in ATP hydrolysis is essential for loading cohesin onto DNA. In addition to functional ATPase heads, an intact cohesin ring structure is indispensable for DNA binding, suggesting that ATP hydrolysis may be coupled to DNA transport into the cohesin ring. DNA is released in anaphase when separase cleaves cohesin's Scc1 subunit. We show that a cleavage fragment of Scc1 disrupts the interaction between the two Smc heads, thereby opening the ring. CONCLUSIONS We present a model for cohesin binding to chromatin by ATP hydrolysis-dependent transport of DNA into the cohesin ring. After DNA replication, two DNA strands may be trapped to promote sister chromatid cohesion. In anaphase, Scc1 cleavage opens the ring to release sister chromatids.
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Affiliation(s)
- Stefan Weitzer
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
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17
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Abstract
During mitosis, in most eukaryotes, cohesin is removed from chromosomes in two steps. A paper in the March issue of Molecular Cell identifies Polo-like kinase as a key regulator for the first step that releases much of cohesin during prophase.
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Affiliation(s)
- Stefan Weitzer
- Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, WC2A 3PX, London, United Kingdom
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18
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Impagnatiello MA, Weitzer S, Gannon G, Compagni A, Cotten M, Christofori G. Mammalian sprouty-1 and -2 are membrane-anchored phosphoprotein inhibitors of growth factor signaling in endothelial cells. J Cell Biol 2001; 152:1087-98. [PMID: 11238463 PMCID: PMC2198812 DOI: 10.1083/jcb.152.5.1087] [Citation(s) in RCA: 232] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Growth factor-induced signaling by receptor tyrosine kinases (RTKs) plays a central role in embryonic development and in pathogenesis and, hence, is tightly controlled by several regulatory proteins. Recently, Sprouty, an inhibitor of Drosophila development-associated RTK signaling, has been discovered. Subsequently, four mammalian Sprouty homologues (Spry-1-4) have been identified. Here, we report the functional characterization of two of them, Spry-1 and -2, in endothelial cells. Overexpressed Spry-1 and -2 inhibit fibroblast growth factor- and vascular endothelial growth factor-induced proliferation and differentiation by repressing pathways leading to p42/44 mitogen-activating protein (MAP) kinase activation. In contrast, although epidermal growth factor-induced proliferation of endothelial cells was also inhibited by Spry-1 and -2, activation of p42/44 MAP kinase was not affected. Biochemical and immunofluorescence analysis of endogenous and overexpressed Spry-1 and -2 reveal that both Spry-1 and -2 are anchored to membranes by palmitoylation and associate with caveolin-1 in perinuclear and vesicular structures. They are phosphorylated on serine residues and, upon growth factor stimulation, a subset is recruited to the leading edge of the plasma membrane. The data indicate that mammalian Spry-1 and -2 are membrane-anchored proteins that negatively regulate angiogenesis-associated RTK signaling, possibly in a RTK-specific fashion.
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Affiliation(s)
| | - Stefan Weitzer
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Grainne Gannon
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Amelia Compagni
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Matt Cotten
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
| | - Gerhard Christofori
- Research Institute of Molecular Pathology, Dr. Bohr-Gasse 7, A-1030 Vienna, Austria
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