1
|
Grimes SL, Denison MR. The Coronavirus helicase in replication. Virus Res 2024; 346:199401. [PMID: 38796132 PMCID: PMC11177069 DOI: 10.1016/j.virusres.2024.199401] [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: 11/30/2023] [Revised: 04/16/2024] [Accepted: 05/17/2024] [Indexed: 05/28/2024]
Abstract
The coronavirus nonstructural protein (nsp) 13 encodes an RNA helicase (nsp13-HEL) with multiple enzymatic functions, including unwinding and nucleoside phosphatase (NTPase) activities. Attempts for enzymatic inactivation have defined the nsp13-HEL as a critical enzyme for viral replication and a high-priority target for antiviral development. Helicases have been shown to play numerous roles beyond their canonical ATPase and unwinding activities, though these functions are just beginning to be explored in coronavirus biology. Recent genetic and biochemical studies, as well as work in structurally-related helicases, have provided evidence that supports new hypotheses for the helicase's potential role in coronavirus replication. Here, we review several aspects of the coronavirus nsp13-HEL, including its reported and proposed functions in viral replication and highlight fundamental areas of research that may aid the development of helicase inhibitors.
Collapse
Affiliation(s)
- Samantha L Grimes
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Mark R Denison
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| |
Collapse
|
2
|
Vadla GP, Singh K, Lorson CL, Lorson MA. The contribution and therapeutic implications of IGHMBP2 mutations on IGHMBP2 biochemical activity and ABT1 association. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167091. [PMID: 38403020 PMCID: PMC10999323 DOI: 10.1016/j.bbadis.2024.167091] [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: 11/16/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
Mutations within immunoglobulin mu DNA binding protein (IGHMBP2), an RNA-DNA helicase, result in SMA with respiratory distress type I (SMARD1) and Charcot Marie Tooth type 2S (CMT2S). The underlying biochemical mechanism of IGHMBP2 is unknown as well as the functional significance of IGHMBP2 mutations in disease severity. Here we report the biochemical mechanisms of IGHMBP2 disease-causing mutations D565N and H924Y, and their potential impact on therapeutic strategies. The IGHMBP2-D565N mutation has been identified in SMARD1 patients, while the IGHMBP2-H924Y mutation has been identified in CMT2S patients. For the first time, we demonstrate a correlation between the altered IGHMBP2 biochemical activity associated with the D565N and H924Y mutations and disease severity and pathology in patients and our Ighmbp2 mouse models. We show that IGHMBP2 mutations that alter the association with activator of basal transcription (ABT1) impact the ATPase and helicase activities of IGHMBP2 and the association with the 47S pre-rRNA 5' external transcribed spacer. We demonstrate that the D565N mutation impairs IGHMBP2 ATPase and helicase activities consistent with disease pathology. The H924Y mutation alters IGHMBP2 activity to a lesser extent while maintaining association with ABT1. In the context of the compound heterozygous patient, we demonstrate that the total biochemical activity associated with IGHMBP2-D565N and IGHMBP2-H924Y proteins is improved over IGHMBP2-D565N alone. Importantly, we demonstrate that the efficacy of therapeutic applications may vary based on the underlying IGHMBP2 mutations and the relative biochemical activity of the mutant IGHMBP2 protein.
Collapse
Affiliation(s)
- Gangadhar P Vadla
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Monique A Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
| |
Collapse
|
3
|
Wery M, Szachnowski U, Andjus S, de Andres-Pablo A, Morillon A. The RNA helicases Dbp2 and Mtr4 regulate the expression of Xrn1-sensitive long non-coding RNAs in yeast. FRONTIERS IN RNA RESEARCH 2023; 1:1244554. [PMID: 37667796 PMCID: PMC7615016 DOI: 10.3389/frnar.2023.1244554] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The expression of yeast long non-coding (lnc)RNAs is restricted by RNA surveillance machineries, including the cytoplasmic 5'-3' exonuclease Xrn1 which targets a conserved family of lncRNAs defined as XUTs, and that are mainly antisense to protein-coding genes. However, the co-factors involved in the degradation of these transcripts and the underlying molecular mechanisms remain largely unknown. Here, we show that two RNA helicases, Dbp2 and Mtr4, act as global regulators of XUTs expression. Using RNA-Seq, we found that most of them accumulate upon Dbp2 inactivation or Mtr4 depletion. Mutants of the cytoplasmic RNA helicases Ecm32, Ski2, Slh1, Dbp1, and Dhh1 did not recapitulate this global stabilization of XUTs, suggesting that XUTs decay is specifically controlled by Dbp2 and Mtr4. Notably, Dbp2 and Mtr4 affect XUTs independently of their configuration relative to their paired-sense mRNAs. Finally, we show that the effect of Dbp2 on XUTs depends on a cytoplasmic localization. Overall, our data indicate that Dbp2 and Mtr4 are global regulators of lncRNAs expression and contribute to shape the non-coding transcriptome together with RNA decay machineries.
Collapse
Affiliation(s)
- Maxime Wery
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Ugo Szachnowski
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Sara Andjus
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL
University, Sorbonne Université, CNRS UMR3244, Paris Cedex, France
| | - Alvaro de Andres-Pablo
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, Sorbonne
Université, CNRS UMR3244, Paris Cedex, France
| |
Collapse
|
4
|
Urakov VN, Mitkevich OV, Safenkova IV, Ter‐Avanesyan MD. Ribosome‐bound Pub1 modulates stop codon decoding during translation termination in yeast. FEBS J 2017; 284:1914-1930. [DOI: 10.1111/febs.14099] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 03/16/2017] [Accepted: 04/28/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Valery N. Urakov
- Federal Research Center ‘Fundamentals of Biotechnology’ of the Russian Academy of Sciences Bach Institute of Biochemistry Moscow Russia
| | - Olga V. Mitkevich
- Federal Research Center ‘Fundamentals of Biotechnology’ of the Russian Academy of Sciences Bach Institute of Biochemistry Moscow Russia
| | - Irina V. Safenkova
- Federal Research Center ‘Fundamentals of Biotechnology’ of the Russian Academy of Sciences Bach Institute of Biochemistry Moscow Russia
| | - Michael D. Ter‐Avanesyan
- Federal Research Center ‘Fundamentals of Biotechnology’ of the Russian Academy of Sciences Bach Institute of Biochemistry Moscow Russia
| |
Collapse
|
5
|
Nizhnikov AA, Antonets KS, Inge-Vechtomov SG, Derkatch IL. Modulation of efficiency of translation termination in Saccharomyces cerevisiae. Prion 2014; 8:247-60. [PMID: 25486049 DOI: 10.4161/pri.29851] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nonsense suppression is a readthrough of premature termination codons. It typically occurs either due to the recognition of stop codons by tRNAs with mutant anticodons, or due to a decrease in the fidelity of translation termination. In the latter case, suppressors usually promote the readthrough of different types of nonsense codons and are thus called omnipotent nonsense suppressors. Omnipotent nonsense suppressors were identified in yeast Saccharomyces cerevisiae in 1960s, and most of subsequent studies were performed in this model organism. Initially, omnipotent suppressors were localized by genetic analysis to different protein- and RNA-encoding genes, mostly the components of translational machinery. Later, nonsense suppression was found to be caused not only by genomic mutations, but also by epigenetic elements, prions. Prions are self-perpetuating protein conformations usually manifested by infectious protein aggregates. Modulation of translational accuracy by prions reflects changes in the activity of their structural proteins involved in different aspects of protein synthesis. Overall, nonsense suppression can be seen as a "phenotypic mirror" of events affecting the accuracy of the translational machine. However, the range of proteins participating in the modulation of translation termination fidelity is not fully elucidated. Recently, the list has been expanded significantly by findings that revealed a number of weak genetic and epigenetic nonsense suppressors, the effect of which can be detected only in specific genetic backgrounds. This review summarizes the data on the nonsense suppressors decreasing the fidelity of translation termination in S. cerevisiae, and discusses the functional significance of the modulation of translational accuracy.
Collapse
Affiliation(s)
- Anton A Nizhnikov
- a Department of Genetics and Biotechnology ; St. Petersburg State University ; St. Petersburg , Russia
| | | | | | | |
Collapse
|
6
|
Jędrzejowska M, Madej-Pilarczyk A, Fidziańska A, Mierzewska H, Pronicka E, Obersztyn E, Gos M, Pronicki M, Kmieć T, Migdał M, Mierzewska-Schmidt M, Walczak-Wojtkowska I, Konopka E, Hausmanowa-Petrusewicz I. Severe phenotypes of SMARD1 associated with novel mutations of the IGHMBP2 gene and nuclear degeneration of muscle and Schwann cells. Eur J Paediatr Neurol 2014; 18:183-92. [PMID: 24388491 DOI: 10.1016/j.ejpn.2013.11.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 11/04/2013] [Indexed: 01/25/2023]
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a very rare autosomal recessive form of spinal muscular atrophy manifested in low birth weight, diaphragmatic palsy and distal muscular atrophy. Caused by a mutation in the IGHMBP2 gene, the disease is addressed here by reference to five Polish patients in which SMARD1 has been confirmed genetically. All presented a severe form of the disease and had evident symptoms during the second month of life; with four displaying weak cries, feeding difficulties and hypotonia from birth. Two were afflicted by severe dysfunction of the autonomic nervous system. Ultrastructural analysis of a muscle biopsy revealed progressive degeneration within the nuclei of the muscle cells and Schwann cells. Neuromuscular junctions were also defective. It proved possible to identify in our patients 6 novel IGHMBP2 mutations: three missense (c.595G>C, c.1682T>C and c.1794C>A), two nonsense (c.94C>T and c.1336C>T) and one in-frame deletion (c.1615_1623del). One nonsense mutation (c.429C>T) that had been described previously was also identified. Observation of our patients makes it clear that clinical picture is still the most important factor suggesting diagnosis of SMARD1, though further investigations concerning some of the symptoms are required. As the IGHMBP2 gene is characterized by significant heterogeneity, genetic counseling of affected families is rendered more complex. IGHMBP2 protein deficiency can lead to the degeneration of nuclei, in both muscle and Schwann cells.
Collapse
Affiliation(s)
- Maria Jędrzejowska
- Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
| | | | - Anna Fidziańska
- Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Mierzewska
- Department of Child and Adolescent Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Ewa Pronicka
- Department of Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland
| | - Ewa Obersztyn
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Monika Gos
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Maciej Pronicki
- Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Tomasz Kmieć
- Department of Neurology and Epileptology, The Children's Memorial Health Institute, Warsaw, Poland
| | - Marek Migdał
- Department of Anaesthesiology and Intensive Care, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Iwona Walczak-Wojtkowska
- Department of Paediatric Anaesthesiology and Intensive Care, Institute of Mother and Child, Warsaw, Poland
| | - Elżbieta Konopka
- Department of Paediatric Anaesthesiology and Intensive Care, Institute of Mother and Child, Warsaw, Poland
| | | |
Collapse
|
7
|
Na I, Reddy KD, Breydo L, Xue B, Uversky VN. A putative role of the Sup35p C-terminal domain in the cytoskeleton organization during yeast mitosis. ACTA ACUST UNITED AC 2014; 10:925-40. [DOI: 10.1039/c3mb70515c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on structural analysis of several effectors and partners, Sup35pC is proposed to serve as actin modulator during mitosis.
Collapse
Affiliation(s)
- Insung Na
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Krishna D. Reddy
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Leonid Breydo
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Bin Xue
- Department of Cell Biology
- Microbiology, and Molecular Biology
- College of Arts and Science
- University of South Florida
- Tampa, USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
- USF Health Byrd Alzheimer's Research Institute
| |
Collapse
|
8
|
Xiao R, Gao Y, Shen Q, Li C, Chang W, Chai B. Polypeptide chain release factor eRF3 is a novel molecular partner of survivin. Cell Biol Int 2013; 37:359-69. [PMID: 23377885 DOI: 10.1002/cbin.10043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 01/07/2013] [Indexed: 01/12/2023]
Abstract
The eukaryotic class II polypeptide chain release factor (eRF3) is an eRF1- and ribosome-dependent GTPase involved in translation termination of protein biosynthesis. eRF3 is a multifunctional protein that is also involved in chromosomal segregation and cytokinesis during mitosis. Survivin is a member of the inhibitor of apoptosis protein (IAP) family that is involved in the organisation of spindle and cell apoptosis. Interaction between survivin and eRF3a-F3 or eRF3b, encoded by the GSPT1 and GSPT2 genes, respectively, was confirmed using yeast two-hybrid (Y2H) and pull-down assays in vitro, and co-immunoprecipitation in vivo. The domains involved in the formation of the survivin-eRF3s complex have been identified. The sites on survivin that interact with eRF3 are located in the baculovirus IAP repeat domain (residues 65-76), which forms a beta-strand structure with an overall negative charge. The sites on eRF3 that interact with survivin were localised to the N-terminal domain(NTD; residues 131-200). Cell localisation experiments indicate that both factors are in the nucleus, suggesting that they cooperatively function in nuclear processes.
Collapse
Affiliation(s)
- Ruilin Xiao
- Key Laboratory of Chemical Biology and Molecular Engineering, Ministry of Education, China; Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | | | | | | | | | | |
Collapse
|
9
|
Hasgall PA, Hoogewijs D, Faza MB, Panse VG, Wenger RH, Camenisch G. The putative RNA helicase HELZ promotes cell proliferation, translation initiation and ribosomal protein S6 phosphorylation. PLoS One 2011; 6:e22107. [PMID: 21765940 PMCID: PMC3135610 DOI: 10.1371/journal.pone.0022107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 06/16/2011] [Indexed: 11/18/2022] Open
Abstract
The hypoxia–inducible transcription factor (HIF) is a key component of the cellular adaptation mechanisms to hypoxic conditions. HIFα subunits are degraded by prolyl-4-hydroxylase domain (PHD) enzyme-dependent prolyl-4-hydroxylation of LxxLAP motifs that confer oxygen-dependent proteolytic degradation. Interestingly, only three non-HIFα proteins contain two conserved LxxLAP motifs, including the putative RNA helicase with a zinc finger domain HELZ. However, HELZ proteolytic regulation was found to be oxygen-independent, supporting the notion that a LxxLAP sequence motif alone is not sufficient for oxygen-dependent protein destruction. Since biochemical pathways involving RNA often require RNA helicases to modulate RNA structure and activity, we used luciferase reporter gene constructs and metabolic labeling to demonstrate that HELZ overexpression activates global protein translation whereas RNA-interference mediated HELZ suppression had the opposite effect. Although HELZ interacted with the poly(A)-binding protein (PABP) via its PAM2 motif, PABP was dispensable for HELZ function in protein translation. Importantly, downregulation of HELZ reduced translational initiation, resulting in the disassembly of polysomes, in a reduction of cell proliferation and hypophosphorylation of ribosomal protein S6.
Collapse
Affiliation(s)
- Philippe A. Hasgall
- Institute of Physiology and Zürich Center for Integrative Human Physiology ZIHP, University of Zürich UZH, Zürich, Switzerland
| | - David Hoogewijs
- Institute of Physiology and Zürich Center for Integrative Human Physiology ZIHP, University of Zürich UZH, Zürich, Switzerland
| | - Marius B. Faza
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | | | - Roland H. Wenger
- Institute of Physiology and Zürich Center for Integrative Human Physiology ZIHP, University of Zürich UZH, Zürich, Switzerland
- * E-mail:
| | - Gieri Camenisch
- Institute of Physiology and Zürich Center for Integrative Human Physiology ZIHP, University of Zürich UZH, Zürich, Switzerland
| |
Collapse
|
10
|
Ju S, Tardiff DF, Han H, Divya K, Zhong Q, Maquat LE, Bosco DA, Hayward LJ, Brown RH, Lindquist S, Ringe D, Petsko GA. A yeast model of FUS/TLS-dependent cytotoxicity. PLoS Biol 2011; 9:e1001052. [PMID: 21541368 PMCID: PMC3082520 DOI: 10.1371/journal.pbio.1001052] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 03/17/2011] [Indexed: 12/12/2022] Open
Abstract
FUS/TLS is a nucleic acid binding protein that, when mutated, can cause a subset of familial amyotrophic lateral sclerosis (fALS). Although FUS/TLS is normally located predominantly in the nucleus, the pathogenic mutant forms of FUS/TLS traffic to, and form inclusions in, the cytoplasm of affected spinal motor neurons or glia. Here we report a yeast model of human FUS/TLS expression that recapitulates multiple salient features of the pathology of the disease-causing mutant proteins, including nuclear to cytoplasmic translocation, inclusion formation, and cytotoxicity. Protein domain analysis indicates that the carboxyl-terminus of FUS/TLS, where most of the ALS-associated mutations are clustered, is required but not sufficient for the toxicity of the protein. A genome-wide genetic screen using a yeast over-expression library identified five yeast DNA/RNA binding proteins, encoded by the yeast genes ECM32, NAM8, SBP1, SKO1, and VHR1, that rescue the toxicity of human FUS/TLS without changing its expression level, cytoplasmic translocation, or inclusion formation. Furthermore, hUPF1, a human homologue of ECM32, also rescues the toxicity of FUS/TLS in this model, validating the yeast model and implicating a possible insufficiency in RNA processing or the RNA quality control machinery in the mechanism of FUS/TLS mediated toxicity. Examination of the effect of FUS/TLS expression on the decay of selected mRNAs in yeast indicates that the nonsense-mediated decay pathway is probably not the major determinant of either toxicity or suppression.
Collapse
Affiliation(s)
- Shulin Ju
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical
Sciences Research Center, Brandeis University, Waltham, Massachusetts, United
States of America
- Department of Neurology and Center for Neurologic Diseases, Harvard
Medical School and Brigham & Women's Hospital, Cambridge,
Massachusetts, United States of America
| | - Daniel F. Tardiff
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts,
United States of America
- Howard Hughes Medical Institute, Department of Biology, Massachusetts
Institute of Technology, Cambridge, Massachusetts, United States of
America
| | - Haesun Han
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts,
United States of America
- Howard Hughes Medical Institute, Department of Biology, Massachusetts
Institute of Technology, Cambridge, Massachusetts, United States of
America
| | - Kanneganti Divya
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical
Sciences Research Center, Brandeis University, Waltham, Massachusetts, United
States of America
| | - Quan Zhong
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston,
Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts,
United States of America
| | - Lynne E. Maquat
- Department of Biochemistry and Biophysics and Center for RNA Biology,
School of Medicine and Dentistry, University of Rochester, Rochester, New York,
United States of America
| | - Daryl A. Bosco
- Department of Neurology, University of Massachusetts Medical School,
Worcester, Massachusetts, United States of America
| | - Lawrence J. Hayward
- Department of Neurology, University of Massachusetts Medical School,
Worcester, Massachusetts, United States of America
| | - Robert H. Brown
- Department of Neurology, University of Massachusetts Medical School,
Worcester, Massachusetts, United States of America
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts,
United States of America
- Howard Hughes Medical Institute, Department of Biology, Massachusetts
Institute of Technology, Cambridge, Massachusetts, United States of
America
| | - Dagmar Ringe
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical
Sciences Research Center, Brandeis University, Waltham, Massachusetts, United
States of America
- Department of Neurology and Center for Neurologic Diseases, Harvard
Medical School and Brigham & Women's Hospital, Cambridge,
Massachusetts, United States of America
| | - Gregory A. Petsko
- Department of Biochemistry and Chemistry, Rosenstiel Basic Medical
Sciences Research Center, Brandeis University, Waltham, Massachusetts, United
States of America
- Department of Neurology and Center for Neurologic Diseases, Harvard
Medical School and Brigham & Women's Hospital, Cambridge,
Massachusetts, United States of America
| |
Collapse
|
11
|
Zhou X, Cooke P, Li L. Eukaryotic release factor 1-2 affects Arabidopsis responses to glucose and phytohormones during germination and early seedling development. JOURNAL OF EXPERIMENTAL BOTANY 2009; 61:357-67. [PMID: 19939886 PMCID: PMC2803205 DOI: 10.1093/jxb/erp308] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 09/22/2009] [Accepted: 10/01/2009] [Indexed: 05/20/2023]
Abstract
Germination and early seedling development are coordinately regulated by glucose and phytohormones such as ABA, GA, and ethylene. However, the molecules that affect plant responses to glucose and phytohormones remain to be fully elucidated. Eukaryotic release factor 1 (eRF1) is responsible for the recognition of the stop codons in mRNAs during protein synthesis. Accumulating evidence indicates that eRF1 functions in other processes in addition to translation termination. The physiological role of eRF1-2, a member of the eRF1 family, in Arabidopsis was examined here. The eRF1-2 gene was found to be specifically induced by glucose. Arabidopsis plants overexpressing eRF1-2 were hypersensitive to glucose during germination and early seedling development. Such hypersensitivity to glucose was accompanied by a dramatic reduction of the expression of glucose-regulated genes, chlorophyll a/b binding protein and plastocyanin. The hypersensitive response was not due to the enhanced accumulation of ABA. In addition, the eRF1-2 overexpressing plants showed increased sensitivity to paclobutrazol, an inhibitor of GA biosynthesis, and exogenous GA restored their normal growth. By contrast, the loss-of-function erf1-2 mutant exhibited resistance to paclobutrazol, suggesting that eRF1-2 may exert a negative effect on the GA signalling pathway. Collectively, these data provide evidence in support of a novel role of eRF1-2 in affecting glucose and phytohormone responses in modulating plant growth and development.
Collapse
Affiliation(s)
- Xiangjun Zhou
- Robert W Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Peter Cooke
- Microscopic Imaging, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA
| | - Li Li
- Robert W Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
12
|
Strawn LA, Lin CA, Tank EMH, Osman MM, Simpson SA, True HL. Mutants of the Paf1 complex alter phenotypic expression of the yeast prion [PSI+]. Mol Biol Cell 2009; 20:2229-41. [PMID: 19225160 DOI: 10.1091/mbc.e08-08-0813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The yeast [PSI+] prion is an epigenetic modifier of translation termination fidelity that causes nonsense suppression. The prion [PSI+] forms when the translation termination factor Sup35p adopts a self-propagating conformation. The presence of the [PSI+] prion modulates survivability in a variety of growth conditions. Nonsense suppression is essential for many [PSI+]-mediated phenotypes, but many do not appear to be due to read-through of a single stop codon, but instead are multigenic traits. We hypothesized that other global mechanisms act in concert with [PSI+] to influence [PSI+]-mediated phenotypes. We have identified one such global regulator, the Paf1 complex (Paf1C). Paf1C is conserved in eukaryotes and has been implicated in several aspects of transcriptional and posttranscriptional regulation. Mutations in Ctr9p and other Paf1C components reduced [PSI+]-mediated nonsense suppression. The CTR9 deletion also alters nonsense suppression afforded by other genetic mutations but not always to the same extent as the effects on [PSI+]-mediated read-through. Our data suggest that the Paf1 complex influences mRNA translatability but not solely through changes in transcript stability or abundance. Finally, we demonstrate that the CTR9 deletion alters several [PSI+]-dependent phenotypes. This provides one example of how [PSI+] and genetic modifiers can interact to uncover and regulate phenotypic variability.
Collapse
Affiliation(s)
- Lisa A Strawn
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | | | | | | | | |
Collapse
|
13
|
Interactions between UPF1, eRFs, PABP and the exon junction complex suggest an integrated model for mammalian NMD pathways. EMBO J 2008; 27:736-47. [PMID: 18256688 DOI: 10.1038/emboj.2008.17] [Citation(s) in RCA: 252] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 01/18/2008] [Indexed: 11/08/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) represents a key mechanism to control the expression of wild-type and aberrant mRNAs. Phosphorylation of the protein UPF1 in the context of translation termination contributes to committing mRNAs to NMD. We report that translation termination is inhibited by UPF1 and stimulated by cytoplasmic poly(A)-binding protein (PABPC1). UPF1 binds to eRF1 and to the GTPase domain of eRF3 both in its GTP- and GDP-bound states. Importantly, mutation studies show that UPF1 can interact with the exon junction complex (EJC) alternatively through either UPF2 or UPF3b to become phosphorylated and to activate NMD. On this basis, we discuss an integrated model where UPF1 halts translation termination and is phosphorylated by SMG1 if the termination-promoting interaction of PABPC1 with eRF3 cannot readily occur. The EJC, with UPF2 or UPF3b as a cofactor, interferes with physiological termination through UPF1. This model integrates previously competing models of NMD and suggests a mechanistic basis for alternative NMD pathways.
Collapse
|
14
|
Kodama H, Ito K, Nakamura Y. The role of N-terminal domain of translational release factor eRF3 for the control of functionality and stability in S. cerevisiae. Genes Cells 2007; 12:639-50. [PMID: 17535254 DOI: 10.1111/j.1365-2443.2007.01082.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translation termination in eukaryotes is mediated by two eukaryotic release factors, eRF1 and eRF3. eRF1 recognizes all three stop codons and induces polypeptide release, while eRF3 binds to eRF1 and participates in translation termination though the regulatory role of eRF3 is still unknown. Importantly, eRF3 interacts with various proteins of distinct biological functions. Here, we investigated the effect of these binding factors on functionality and stability of eRF3 using a temperature-sensitive mutant eRF3ts, which is susceptible to factor binding to change the growth phenotype or cellular protein level. Of factors tested, Itt1 over-expression and Sla1 knockout severely impaired viability of eRF3ts cell and its protein abundance in permissive and semipermissive conditions. Sla1 over-expression reversed the phenotype. It is reported that Itt1 and Sla1 bind to the N-terminal extension domain (NED) of eRF3, unlike the other no-effect factors that bind to the C-terminal domain (CTD). Although NED itself is dispensable, NED-less eRF3ts altered in the stability and functionality. Moreover, Itt1-induced eRF3ts lethality was significantly restored by pep4, prb1 and prc1 knockouts that are defective in vacuolar proteolysis. These findings suggest that NED functions to switch the functional mode of eRF3 depending on the nature of binding factors.
Collapse
Affiliation(s)
- Hiroyuki Kodama
- Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | | | | |
Collapse
|
15
|
von der Haar T, Tuite MF. Regulated translational bypass of stop codons in yeast. Trends Microbiol 2006; 15:78-86. [PMID: 17187982 DOI: 10.1016/j.tim.2006.12.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/13/2006] [Accepted: 12/07/2006] [Indexed: 10/23/2022]
Abstract
Stop codons are used to signal the ribosome to terminate the decoding of an mRNA template. Recent studies on translation termination in the yeast Saccharomyces cerevisiae have not only enabled the identification of the key components of the termination machinery, but have also revealed several regulatory mechanisms that might enable the controlled synthesis of C-terminally extended polypeptides via stop-codon readthrough. These include both genetic and epigenetic mechanisms. Rather than being a translation 'error', stop-codon readthrough can have important effects on other cellular processes such as mRNA degradation and, in some cases, can confer a beneficial phenotype to the cell.
Collapse
Affiliation(s)
- Tobias von der Haar
- Protein Science Group, Department of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.
| | | |
Collapse
|
16
|
Abstract
As concepts evolve in mammalian and yeast prion biology, rather preliminary research investigating the interplay between prion and RNA processes are gaining momentum. The yeast prion [PSI+] represents an aggregated state of the translation termination factor Sup35 resulting in the tendency of ribosomes to readthrough stop codons. This "nonsense suppression" activity is investigated for its possible physiological role to engender on Saccharomyces cerevisiae the ability to respond to stress or variable growth conditions and thereby act as a capacitor to evolve. The interaction between prion and RNA is a two way street--the cell may have adopted RNA processes in translation to govern the presence of prions and the [PSI+] prion's nonsense suppressor phenotype may exhibit different growth phenotypes by its control of translation termination. RNA processes in the mammalian cell also effect and are affected by prions.
Collapse
Affiliation(s)
- Colin G Crist
- Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639
| | | |
Collapse
|
17
|
Rospert S, Rakwalska M, Dubaquié Y. Polypeptide chain termination and stop codon readthrough on eukaryotic ribosomes. REVIEWS OF PHYSIOLOGY BIOCHEMISTRY AND PHARMACOLOGY 2006; 155:1-30. [PMID: 15928926 DOI: 10.1007/3-540-28217-3_1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
During protein translation, a variety of quality control checks ensure that the resulting polypeptides deviate minimally from their genetic encoding template. Translational fidelity is central in order to preserve the function and integrity of each cell. Correct termination is an important aspect of translational fidelity, and a multitude of mechanisms and players participate in this exquisitely regulated process. This review explores our current understanding of eukaryotic termination by highlighting the roles of the different ribosomal components as well as termination factors and ribosome-associated proteins, such as chaperones.
Collapse
Affiliation(s)
- S Rospert
- Universität Freiburg, Institut für Biochemie und Molekularbiologie, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany.
| | | | | |
Collapse
|
18
|
Petsch KA, Mylne J, Botella JR. Cosuppression of eukaryotic release factor 1-1 in Arabidopsis affects cell elongation and radial cell division. PLANT PHYSIOLOGY 2005; 139:115-26. [PMID: 16113224 PMCID: PMC1203362 DOI: 10.1104/pp.105.062695] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2005] [Revised: 05/30/2005] [Accepted: 05/30/2005] [Indexed: 05/04/2023]
Abstract
The role of the eukaryotic release factor 1 (eRF1) in translation termination has previously been established in yeast; however, only limited characterization has been performed on any plant homologs. Here, we demonstrate that cosuppression of eRF1-1 in Arabidopsis (Arabidopsis thaliana) has a profound effect on plant morphology, resulting in what we term the broomhead phenotype. These plants primarily exhibit a reduction in internode elongation causing the formation of a broomhead-like cluster of malformed siliques at the top of the inflorescence stem. Histological analysis of broomhead stems revealed that cells are reduced in height and display ectopic lignification of the phloem cap cells, some phloem sieve cells, and regions of the fascicular cambium, as well as enhanced lignification of the interfascicular fibers. We also show that cell division in the fascicular cambial regions is altered, with the majority of vascular bundles containing cambial cells that are disorganized and possess enlarged nuclei. This is the first attempt at functional characterization of a release factor in vivo in plants and demonstrates the importance of eRF1-1 function in Arabidopsis.
Collapse
Affiliation(s)
- Katherine Anne Petsch
- Plant Genetic Engineering Laboratory, Department of Botany, School of Integrative Biology, University of Queensland, Brisbane, Australia
| | | | | |
Collapse
|
19
|
Duttagupta R, Tian B, Wilusz CJ, Khounh DT, Soteropoulos P, Ouyang M, Dougherty JP, Peltz SW. Global analysis of Pub1p targets reveals a coordinate control of gene expression through modulation of binding and stability. Mol Cell Biol 2005; 25:5499-513. [PMID: 15964806 PMCID: PMC1156976 DOI: 10.1128/mcb.25.13.5499-5513.2005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Regulation of mRNA turnover is an important cellular strategy for posttranscriptional control of gene expression, mediated by the interplay of cis-acting sequences and associated trans-acting factors. Pub1p, an ELAV-like yeast RNA-binding protein with homology to T-cell internal antigen 1 (TIA-1)/TIA-1-related protein (TIAR), is an important modulator of the decay of two known classes of mRNA. Our goal in this study was to determine the range of mRNAs whose stability is dependent on Pub1p, as well as to identify specific transcripts that directly bind to this protein. We have examined global mRNA turnover in isogenic PUB1 and pub1delta strains through gene expression analysis and demonstrate that 573 genes exhibit a significant reduction in half-life in a pub1delta strain. We also examine the binding specificity of Pub1p using affinity purification followed by microarray analysis to comprehensively distinguish between direct and indirect targets and find that Pub1p significantly binds to 368 cellular transcripts. Among the Pub1p-associated mRNAs, 53 transcripts encoding proteins involved in ribosomal biogenesis and cellular metabolism are selectively destabilized in the pub1delta strain. In contrast, genes involved in transporter activity demonstrate association with Pub1p but display no measurable changes in transcript stability. Characterization of two candidate genes, SEC53 and RPS16B, demonstrate that both Pub1p-dependent regulation of stability and Pub1p binding require 3' untranslated regions, which harbor distinct sequence motifs. These results suggest that Pub1p binds to discrete subsets of cellular transcripts and posttranscriptionally regulates their expression at multiple levels.
Collapse
Affiliation(s)
- Radharani Duttagupta
- Department of Molecular Genetics, Microbiology, and Immunology, UMDNJ-Robert Wood Johnson Medical School, 675 Hoes Ln., Piscataway, New Jersey 08854-5627, USA
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Rospert S, Rakwalska M, Dubaquié Y. Polypeptide chain termination and stop codon readthrough on eukaryotic ribosomes. Rev Physiol Biochem Pharmacol 2005. [DOI: 10.1007/s10254-005-0039-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
21
|
de Pinto B, Lippolis R, Castaldo R, Altamura N. Overexpression of Upf1p compensates for mitochondrial splicing deficiency independently of its role in mRNA surveillance. Mol Microbiol 2004; 51:1129-42. [PMID: 14763985 DOI: 10.1046/j.1365-2958.2003.03889.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In yeast the UPF1, UPF2 and UPF3 genes encode three interacting factors involved in translation termination and nonsense-mediated mRNA decay (NMD). UPF1 plays a central role in both processes. In addition, UPF1 was originally isolated as a multicopy suppressor of mitochondrial splicing deficiency, and its deletion leads to an impairment in respiratory growth. Here, we provide evidence that inactivation of UPF2 or UPF3, like that of UPF1, leads to an impairment in respiratory competence, suggesting that their products, Upf1p, Upf2p and Upf3p, are equivalently involved in mitochondrial biogenesis. In addition, however, we show that only Upf1p acts as a multicopy suppressor of mitochondrial splicing deficiency, and its activity does not require either Upf2p or Upf3p. Mutations in the conserved cysteine- and histidine-rich regions and ATPase and helicase motifs of Upf1p separate the ability of Upf1p to complement the respiratory impairment of a Deltaupf1 strain from its ability to act as a multicopy suppressor of mitochondrial splicing deficiency, indicating that distinct pathways express these phenotypes. In addition, we show that, when overexpressed, Upf1p is not detected within mitochondria, suggesting that its role as multicopy suppressor of mitochondrial splicing deficiency is indirect. Furthermore, we provide evidence that cells overexpressing certain upf1 alleles accumulate a phosphorylated isoform of Upf1p. Altogether, these results indicate that overexpression of Upf1p compensates for mitochondrial splicing deficiency independently of its role in mRNA surveillance, which relies on Upf1p-Upf2p-Upf3p functional interplay.
Collapse
Affiliation(s)
- B de Pinto
- Consiglio Nazionale delle Ricerche, Istituto di Biomembrane e Bioenergetica, Bari, Italy
| | | | | | | |
Collapse
|
22
|
Tork S, Hatin I, Rousset JP, Fabret C. The major 5' determinant in stop codon read-through involves two adjacent adenines. Nucleic Acids Res 2004; 32:415-21. [PMID: 14736996 PMCID: PMC373328 DOI: 10.1093/nar/gkh201] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aim of this approach was to identify the major determinants, located at the 5' end of the stop codon, that modulate translational read-through in Saccharomyces cerevisiae. We developed a library of oligonucleotides degenerate at the six positions immediately upstream of the termination codon, cloned in the ADE2 reporter gene. Variations at these positions modulated translational read-through efficiency approximately 16-fold. The major effect was imposed by the two nucleotides immediately upstream of the stop codon. We showed that this effect was neither mediated by the last amino acid residues present in the polypeptide chain nor by the tRNA present in the ribosomal P site. We propose that the mRNA structure, depending on the nucleotides in the P site, is the main 5' determinant of read-through efficiency.
Collapse
MESH Headings
- Adenine Nucleotides/genetics
- Base Composition
- Base Sequence
- Binding Sites
- Codon, Terminator/genetics
- Gene Library
- Genes, Fungal/genetics
- Genes, Reporter/genetics
- Nucleic Acid Conformation
- Oligoribonucleotides/chemistry
- Oligoribonucleotides/genetics
- Oligoribonucleotides/metabolism
- Peptide Chain Elongation, Translational/genetics
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- Regulatory Sequences, Ribonucleic Acid/genetics
- Ribosomes/genetics
- Ribosomes/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae Proteins/genetics
Collapse
Affiliation(s)
- Sanaa Tork
- CNRS UMR 8621, Institut de Génétique et Microbiologie, Université Paris-Sud, 91405 Orsay Cedex, France
| | | | | | | |
Collapse
|
23
|
Inagaki Y, Blouin C, Susko E, Roger AJ. Assessing functional divergence in EF-1alpha and its paralogs in eukaryotes and archaebacteria. Nucleic Acids Res 2003; 31:4227-37. [PMID: 12853641 PMCID: PMC165955 DOI: 10.1093/nar/gkg440] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A number of methods have recently been published that use phylogenetic information extracted from large multiple sequence alignments to detect sites that have changed properties in related protein families. In this study we use such methods to assess functional divergence between eukaryotic EF-1alpha (eEF-1alpha), archaebacterial EF-1alpha (aEF-1alpha) and two eukaryote-specific EF-1alpha paralogs-eukaryotic release factor 3 (eRF3) and Hsp70 subfamily B suppressor 1 (HBS1). Overall, the evolutionary modes of aEF-1alpha, HBS1 and eRF3 appear to significantly differ from that of eEF-1alpha. However, functionally divergent (FD) sites detected between aEF-1alpha and eEF-1alpha only weakly overlap with sites implicated as putative EF-1beta or aminoacyl-tRNA (aa-tRNA) binding residues in EF-1alpha, as expected based on the shared ancestral primary translational functions of these two orthologs. In contrast, FD sites detected between eEF-1alpha and its paralogs significantly overlap with the putative EF-1beta and/or aa-tRNA binding sites in EF-1alpha. In eRF3 and HBS1, these sites appear to be released from functional constraints, indicating that they bind neither eEF-1beta nor aa-tRNA. These results are consistent with experimental observations that eRF3 does not bind to aa-tRNA, but do not support the 'EF-1alpha-like' function recently proposed for HBS1. We re-assess the available genetic data for HBS1 in light of our analyses, and propose that this protein may function in stop codon-independent peptide release.
Collapse
Affiliation(s)
- Yuji Inagaki
- Program in Evolutionary Biology, Canadian Institute for Advanced Research and Genome Atlantic, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada.
| | | | | | | |
Collapse
|
24
|
Bradley ME, Bagriantsev S, Vishveshwara N, Liebman SW. Guanidine reduces stop codon read-through caused by missense mutations in SUP35 or SUP45. Yeast 2003; 20:625-32. [PMID: 12734800 DOI: 10.1002/yea.985] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Sup35 and Sup45 are essential protein components of the Saccharomyces cerevisiae translation termination factor. Yeast cells harbouring the [PSI(+)] prion form of Sup35 have impaired stop codon recognition (nonsense suppression). It has long been known that the [PSI(+)] prion is not stably transmitted to daughter cells when yeast are grown in the presence of mM concentrations of guanidine hydrochloride (GuHCl). In this paper, Mendelian suppressor mutations whose phenotypes are likewise hidden during growth in the presence of millimolar GuHCl are described. Such GuHCl-remedial Mendelian suppressors were selected under conditions where [PSI(+)] appearance was limiting, and were caused by missense mutations in SUP35 or SUP45. Clearly, anti-suppression caused by growth in the presence of GuHCl is not sufficient to distinguish missense mutations in SUP35 or SUP45, from [PSI(+)]. However, the Mendelian and prion suppressors can be distinguished by subsequent growth in the absence of GuHCl, where only the nonsense suppression caused by the [PSI(+)] prion remains cured. Recent reports indicate that GuHCl blocks the inheritance of [PSI(+)] by directly inhibiting the activity of the protein remodelling factor Hsp104, which is required for the transmission of [PSI(+)] from mother to daughter cells. However, the nonsense suppressor activity caused by the GuHCl-remedial sup35 or sup45 suppressors does not require Hsp104. Thus, GuHCl must anti-suppress the sup35 and sup45 mutations via an in vivo target distinct from Hsp104.
Collapse
Affiliation(s)
- Michael E Bradley
- Laboratory for Molecular Biology, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | | | | | | |
Collapse
|
25
|
Kisselev L, Ehrenberg M, Frolova L. Termination of translation: interplay of mRNA, rRNAs and release factors? EMBO J 2003; 22:175-82. [PMID: 12514123 PMCID: PMC140092 DOI: 10.1093/emboj/cdg017] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Termination of translation in eukaryotes has focused recently on functional anatomy of polypeptide chain release factor, eRF1, by using a variety of different approaches. The tight correlation between the domain structure and different functions of eRF1 has been revealed. Independently, the role of prokaryotic RF1/2 in GTPase activity of RF3 has been deciphered, as well as RF3 function itself.
Collapse
Affiliation(s)
- Lev Kisselev
- Engelhardt Institute of Molecular Biology, 119991 Moscow, Russia and
Department of Cell and Molecular Biology, BMC, Uppsala University, Box 596, S75124 Uppsala, Sweden Corresponding author e-mail:
| | - Måns Ehrenberg
- Engelhardt Institute of Molecular Biology, 119991 Moscow, Russia and
Department of Cell and Molecular Biology, BMC, Uppsala University, Box 596, S75124 Uppsala, Sweden Corresponding author e-mail:
| | | |
Collapse
|
26
|
Valouev IA, Kushnirov VV, Ter-Avanesyan MD. Yeast polypeptide chain release factors eRF1 and eRF3 are involved in cytoskeleton organization and cell cycle regulation. CELL MOTILITY AND THE CYTOSKELETON 2002; 52:161-73. [PMID: 12112144 DOI: 10.1002/cm.10040] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Termination of translation in eukaryotes is controlled by two interacting polypeptide chain release factors, eRF1 and eRF3. eRF1 recognizes nonsense codons UAA, UAG, and UGA, while eRF3 stimulates polypeptide release from the ribosome in a GTP- and eRF1-dependent manner. In the yeast Saccharomyces cerevisiae, eRF1 and eRF3 are encoded by the SUP45 and SUP35 genes, respectively. Here we show that in yeast shortage of any one of the release factors was accompanied by a reduction in the levels of the other release factor and resulted in a substantial increase of nonsense codon readthrough. Besides, repression of the genes encoding these factors caused different effects on cell morphology. Repression of the SUP35 gene caused accumulation of cells of increased size with large buds. This was accompanied by the disappearance of actin cytoskeletal structures, impairment of the mitotic spindle structure, and defects in nuclei division and segregation in mitosis. The evolutionary conserved C-terminal domain of eRF3 similar to the elongation factor EF-1alpha was responsible for these effects. Repression of the SUP45 gene caused accumulation of unbudded cells with 2C and higher DNA content, indicating that DNA replication is uncoupled from budding. The data obtained suggest that eRF1 and eRF3 play additional, nontranslational roles in the yeast cell.
Collapse
Affiliation(s)
- Igor A Valouev
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, Russia
| | | | | |
Collapse
|
27
|
Ito K, Frolova L, Seit-Nebi A, Karamyshev A, Kisselev L, Nakamura Y. Omnipotent decoding potential resides in eukaryotic translation termination factor eRF1 of variant-code organisms and is modulated by the interactions of amino acid sequences within domain 1. Proc Natl Acad Sci U S A 2002; 99:8494-9. [PMID: 12084909 PMCID: PMC124286 DOI: 10.1073/pnas.142690099] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, a single translational release factor, eRF1, deciphers three stop codons, although its decoding mechanism remains puzzling. In the ciliate Tetrahymena thermophila, UAA and UAG codons are reassigned to Gln codons. A yeast eRF1-domain swap containing Tetrahymena domain 1 responded only to UGA in vitro and failed to complement a defect in yeast eRF1 in vivo at 37 degrees C. This finding demonstrates that decoding specificity of eRF1 from variant code organisms resides at domain 1. However, the wild-type eRF1 hybrid fully restored the growth of eRF1-deficient yeast at 30 degrees C. Tetrahymena eRF1 contains a variant sequence, KATNIKD, at the tip of domain 1. The TASNIKD variant of hybrid eRF1 rendered the eRF1-nullified yeast viable, although in an in vitro assay, the same hybrid eRF1 responded only to UGA. Nevertheless, the yeast eRF1 bearing the KATNIKD motif instead of the TASNIKS heptapeptide present in higher eukaryotes remains omnipotent in vivo. Collectively, these data suggest that variant genetic code organisms like Tetrahymena have an intrinsic potential to decode three stop codons in vivo, and that interaction within domain 1 between the KAT tripeptide and other sequences modulates the decoding specificity of Tetrahymena eRF1.
Collapse
Affiliation(s)
- Koichi Ito
- Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | | | | | | | | | | |
Collapse
|
28
|
Namy O, Hatin I, Stahl G, Liu H, Barnay S, Bidou L, Rousset JP. Gene overexpression as a tool for identifying new trans-acting factors involved in translation termination in Saccharomyces cerevisiae. Genetics 2002; 161:585-94. [PMID: 12072456 PMCID: PMC1462122 DOI: 10.1093/genetics/161.2.585] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In eukaryotes, translation termination is dependent on the availability of both release factors, eRF1 and eRF3; however, the precise mechanisms involved remain poorly understood. In particular, the fact that the phenotype of release factor mutants is pleiotropic could imply that other factors and interactions are involved in translation termination. To identify unknown elements involved in this process, we performed a genetic screen using a reporter strain in which a leaky stop codon is inserted in the lacZ reporter gene, attempting to isolate factors modifying termination efficiency when overexpressed. Twelve suppressors and 11 antisuppressors, increasing or decreasing termination readthrough, respectively, were identified and analyzed for three secondary phenotypes often associated with translation mutations: thermosensitivity, G418 sensitivity, and sensitivity to osmotic pressure. Interestingly, among these candidates, we identified two genes, SSO1 and STU2, involved in protein transport and spindle pole body formation, respectively, suggesting puzzling connections with the translation termination process.
Collapse
Affiliation(s)
- Olivier Namy
- Laboratoire de Génétique Moléculaire de la Traduction, Institut de Génétique et Microbiologie, CNRS UMR8621, Université Paris-Sud, 91405 Orsay Cedex, France
| | | | | | | | | | | | | |
Collapse
|
29
|
Cosson B, Couturier A, Chabelskaya S, Kiktev D, Inge-Vechtomov S, Philippe M, Zhouravleva G. Poly(A)-binding protein acts in translation termination via eukaryotic release factor 3 interaction and does not influence [PSI(+)] propagation. Mol Cell Biol 2002; 22:3301-15. [PMID: 11971964 PMCID: PMC133780 DOI: 10.1128/mcb.22.10.3301-3315.2002] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent studies of translational control suggest that translation termination may not be simply the end of synthesizing a protein but rather be involved in modulating both the translation efficiency and stability of a given transcript. Using recombinant eukaryotic release factor 3 (eRF3) and cellular extracts, we have shown for Saccharomyces cerevisiae that yeast eRF3 and Pab1p can interact. This interaction, mediated by the N+M domain of eRF3 and amino acids 473 to 577 of Pab1p, was demonstrated to be direct by the two-hybrid approach. We confirmed that a genetic interaction exists between eRF3 and Pab1p and showed that Pab1p overexpression enhances the efficiency of termination in SUP35 (eRF3) mutant and [PSI(+)] cells. This effect requires the interaction of Pab1p with eRF3. These data further strengthen the possibility that Pab1p has a role in coupling translation termination events with initiation of translation. Several lines of evidence indicate that Pab1p does not influence [PSI(+)] propagation. First, "[PSI(+)]-no-more" mutations do not affect eRF3-Pab1p two-hybrid interaction. Second, overexpression of PAB1 does not cure the [PSI(+)] phenotype or solubilize detectable amounts of eRF3. Third, prion-curing properties of overexpressed HSP104p, which is required for formation and maintenance of [PSI(+)], were not modified by excess Pab1p.
Collapse
Affiliation(s)
- Bertrand Cosson
- Universite de Rennes 1, CNRS UMR 6061, 35043 Rennes Cedex, France
| | | | | | | | | | | | | |
Collapse
|
30
|
Volkov KV, Aksenova AY, Soom MJ, Osipov KV, Svitin AV, Kurischko C, Shkundina IS, Ter-Avanesyan MD, Inge-Vechtomov SG, Mironova LN. Novel non-Mendelian determinant involved in the control of translation accuracy in Saccharomyces cerevisiae. Genetics 2002; 160:25-36. [PMID: 11805042 PMCID: PMC1461950 DOI: 10.1093/genetics/160.1.25] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Two cytoplasmically inherited determinants related by their manifestation to the control of translation accuracy were previously described in yeast. Cells carrying one of them, [PSI(+)], display a nonsense suppressor phenotype and contain a prion form of the Sup35 protein. Another element, [PIN(+)], determines the probability of de novo generation of [PSI(+)] and results from a prion form of several proteins, which can be functionally unrelated to Sup35p. Here we describe a novel nonchromosomal determinant related to the SUP35 gene. This determinant, designated [ISP(+)], was identified as an antisuppressor of certain sup35 mutations. We observed its loss upon growth on guanidine hydrochloride and subsequent spontaneous reappearance with high frequency. The reversible curability of [ISP(+)] resembles the behavior of yeast prions. However, in contrast to known prions, [ISP(+)] does not depend on the chaperone protein Hsp104. Though manifestation of both [ISP(+)] and [PSI(+)] is related to the SUP35 gene, the maintenance of [ISP(+)] does not depend on the prionogenic N-terminal domain of Sup35p and Sup35p is not aggregated in [ISP(+)] cells, thus ruling out the possibility that [ISP(+)] is a specific form of [PSI(+)]. We hypothesize that [ISP(+)] is a novel prion involved in the control of translation accuracy in yeast.
Collapse
Affiliation(s)
- Kirill V Volkov
- Department of Genetics, St. Petersburg State University, St. Petersburg 199034, Russia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Bond AT, Mangus DA, He F, Jacobson A. Absence of Dbp2p alters both nonsense-mediated mRNA decay and rRNA processing. Mol Cell Biol 2001; 21:7366-79. [PMID: 11585918 PMCID: PMC99910 DOI: 10.1128/mcb.21.21.7366-7379.2001] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Dbp2p, a member of the large family of DEAD-box proteins and a yeast homolog of human p68, was shown to interact with Upf1p, an essential component of the nonsense-mediated mRNA decay pathway. Dbp2p:Upf1p interaction occurs within a large conserved region in the middle of Upf1p that is largely distinct from its Nmd2p and Sup35/45p interaction domains. Deletion of DBP2, or point mutations within its highly conserved DEAD-box motifs, increased the abundance of nonsense-containing transcripts, leading us to conclude that Dbp2p also functions in the nonsense-mediated mRNA decay pathway. Dbp2p, like Upf1p, acts before or at decapping, is predominantly cytoplasmic, and associates with polyribosomes. Interestingly, Dbp2p also plays an important role in rRNA processing. In dbp2Delta cells, polyribosome profiles are deficient in free 60S subunits and the mature 25S rRNA is greatly reduced. The ribosome biogenesis phenotype, but not the mRNA decay function, of dbp2Delta cells can be complemented by the human p68 gene. We propose a unifying model in which Dbp2p affects both nonsense-mediated mRNA decay and rRNA processing by altering rRNA structure, allowing specific processing events in one instance and facilitating dissociation of the translation termination complex in the other.
Collapse
Affiliation(s)
- A T Bond
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0122, USA
| | | | | | | |
Collapse
|
32
|
Urakov VN, Valouev IA, Lewitin EI, Paushkin SV, Kosorukov VS, Kushnirov VV, Smirnov VN, Ter-Avanesyan MD. Itt1p, a novel protein inhibiting translation termination in Saccharomyces cerevisiae. BMC Mol Biol 2001; 2:9. [PMID: 11570975 PMCID: PMC56590 DOI: 10.1186/1471-2199-2-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Accepted: 08/24/2001] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Termination of translation in eukaryotes is controlled by two interacting polypeptide chain release factors, eRFl and eRF3. eRFl recognizes nonsense codons UAA, UAG and UGA, while eRF3 stimulates polypeptide release from the ribosome in a GTP- and eRFl - dependent manner. Recent studies has shown that proteins interacting with these release factors can modulate the efficiency of nonsense codon readthrough. RESULTS We have isolated a nonessential yeast gene, which causes suppression of nonsense mutations, being in a multicopy state. This gene encodes a protein designated Itt1p, possessing a zinc finger domain characteristic of the TRIAD proteins of higher eukaryotes. Overexpression of Itt1p decreases the efficiency of translation termination, resulting in the readthrough of all three types of nonsense codons. Itt1p interacts in vitro with both eRFl and eRF3. Overexpression of eRFl, but not of eRF3, abolishes the nonsense suppressor effect of overexpressed Itt1p. CONCLUSIONS The data obtained demonstrate that Itt1p can modulate the efficiency of translation termination in yeast. This protein possesses a zinc finger domain characteristic of the TRIAD proteins of higher eukaryotes, and this is a first observation of such protein being involved in translation.
Collapse
Affiliation(s)
- Valery N Urakov
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, 121552, Russia
| | - Igor A Valouev
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, 121552, Russia
| | - Eugeny I Lewitin
- School of Biology, Georgia Institute of Technology, Atlanta, GA, 30332-0230, USA
| | - Sergey V Paushkin
- Howard Hughes Medical Institute, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Vyacheslav S Kosorukov
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, 121552, Russia
| | - Vitaly V Kushnirov
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, 121552, Russia
| | - Vladimir N Smirnov
- Institute of Experimental Cardiology, Cardiology Research Center, Moscow, 121552, Russia
| | | |
Collapse
|
33
|
Abstract
Nonsense-mediated mRNA decay (NMD), the loss of mRNAs carrying premature stop codons, is a process by which cells recognize and degrade nonsense mRNAs to prevent possibly toxic effects of truncated peptides. Most mammalian nonsense mRNAs are degraded while associated with the nucleus, but a few are degraded in the cytoplasm; at either site, there is a requirement for translation and for an intron downstream of the early stop codon. We have examined the NMD of a mutant HEXA message in lymphoblasts derived from a Tay-Sachs disease patient homozygous for the common frameshift mutation 1278ins4. The mutant mRNA was nearly undetectable in these cells and increased to approximately 40% of normal in the presence of the translation inhibitor cycloheximide. The stabilized transcript was found in the cytoplasm in association with polysomes. Within 5 h of cycloheximide removal, the polysome-associated nonsense message was completely degraded, while the normal message was stable. The increased lability of the polysome-associated mutant HEXA mRNA shows that NMD of this endogenous mRNA occurred in the cytoplasm. Transfection of Chinese hamster ovary cells showed that expression of an intronless HEXA minigene harboring the frameshift mutation or a closely located nonsense codon resulted in half the normal mRNA level. Inclusion of multiple downstream introns decreased the abundance further, to about 20% of normal. Thus, in contrast to other systems, introns are not absolutely required for NMD of HEXA mRNA, although they enhance the low-HEXA-mRNA phenotype.
Collapse
Affiliation(s)
- K S Rajavel
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095-1737, USA
| | | |
Collapse
|
34
|
Affiliation(s)
- M Kozak
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854, USA.
| |
Collapse
|