1
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Wanat JJ, McCann JJ, Tingey M, Atkins J, Merlino CO, Lee-Soety JY. Yeast Npl3 regulates replicative senescence outside of TERRA R-loop resolution and co-transcriptional processing. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2024:1-21. [PMID: 38976968 DOI: 10.1080/15257770.2024.2374023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 06/20/2024] [Indexed: 07/10/2024]
Abstract
Eukaryotic cells without telomerase experience progressively shorter telomeres with each round of cell division until cell cycle arrest is initiated, leading to replicative senescence. When yeast TLC1, which encodes the RNA template of telomerase, is deleted, senescence is accompanied by increased expression of TERRA (non-coding telomere repeat-containing RNA). Deletion of Npl3, an RNA-processing protein with telomere maintenance functions, accelerates senescence in tlc1Δ cells and significantly increases TERRA levels. Using genetic approaches, we set out to determine how Npl3 is involved in regulating TERRA expression and maintaining telomere homeostasis. Even though Npl3 regulates hyperrecombination, we found that Npl3 does not help resolve RNA:DNA hybrids formed during TERRA synthesis in the same way as RNase H1 and H2. Furthermore, Rad52 is still required for cells to escape senescence by telomere recombination in the absence of Npl3. Npl3 also works separately from the THO/TREX pathway for processing nascent RNA for nuclear export. However, deleting Dot1, a histone methyltransferase involved in tethering telomeres to the nuclear periphery, rescued the accelerated senescence phenotype of npl3Δ cells. Thus, our study suggests that Npl3 plays an additional role in regulating cellular senescence outside of RNA:DNA hybrid resolution and co-transcriptional processing.
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Affiliation(s)
- Jennifer J Wanat
- Department of Biology, Washington College, Chestertown, Maryland, USA
| | - Jennifer J McCann
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Mark Tingey
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Jessica Atkins
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Corinne O Merlino
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
| | - Julia Y Lee-Soety
- Department of Biology, Saint Joseph's University, Philadelphia, Pennsylvania, USA
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2
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Colón EM, Haddock LA, Lasalde C, Lin Q, Ramírez-Lugo JS, González CI. Characterization of the mIF4G Domains in the RNA Surveillance Protein Upf2p. Curr Issues Mol Biol 2023; 46:244-261. [PMID: 38248319 PMCID: PMC10814901 DOI: 10.3390/cimb46010017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/11/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
Thirty percent of all mutations causing human disease generate mRNAs with premature termination codons (PTCs). Recognition and degradation of these PTC-containing mRNAs is carried out by the mechanism known as nonsense-mediated mRNA decay (NMD). Upf2 is a scaffold protein known to be a central component of the NMD surveillance pathway. It harbors three middle domains of eukaryotic initiation factor 4G (mIF4G-1, mIF4G-2, mIF4G-3) in its N-terminal region that are potentially important in regulating the surveillance pathway. In this study, we defined regions within the mIF4G-1 and mIF4G-2 that are required for proper function of Upf2p in NMD and translation termination in Saccharomyces cerevisiae. In addition, we narrowed down the activity of these regions to an aspartic acid (D59) in mIF4G-1 that is important for NMD activity and translation termination accuracy. Taken together, these studies suggest that inherently charged residues within mIF4G-1 of Upf2p play a role in the regulation of the NMD surveillance mechanism in S. cerevisiae.
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Affiliation(s)
- Edgardo M. Colón
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
| | - Luis A. Haddock
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
| | - Clarivel Lasalde
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
| | - Qishan Lin
- Department of Chemistry, University at Albany, Albany, NY 12222, USA;
- RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY 12222, USA
| | - Juan S. Ramírez-Lugo
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
| | - Carlos I. González
- Department of Biology, Río Piedras Campus, University of Puerto Rico, San Juan, PR 00931, USA (C.L.); (J.S.R.-L.)
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR 00926, USA
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3
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Asada R, Dominguez A, Montpetit B. Single-molecule quantitation of RNA-binding protein occupancy and stoichiometry defines a role for Yra1 (Aly/REF) in nuclear mRNP organization. Cell Rep 2023; 42:113415. [PMID: 37963019 PMCID: PMC10841842 DOI: 10.1016/j.celrep.2023.113415] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/09/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
RNA-binding proteins (RBPs) interact with mRNA to form supramolecular complexes called messenger ribonucleoprotein (mRNP) particles. These dynamic assemblies direct and regulate individual steps of gene expression; however, their composition and functional importance remain largely unknown. Here, we develop a total internal reflection fluorescence-based single-molecule imaging assay to investigate stoichiometry and co-occupancy of 15 RBPs within mRNPs from Saccharomyces cerevisiae. We show compositional heterogeneity of single mRNPs and plasticity across different growth conditions, with major co-occupants of mRNPs containing the nuclear cap-binding complex identified as Yra1 (1-10 copies), Nab2 (1-6 copies), and Npl3 (1-6 copies). Multicopy Yra1-bound mRNPs are specifically co-occupied by the THO complex and assembled on mRNAs biased by transcript length and RNA secondary structure. Yra1 depletion results in decreased compaction of nuclear mRNPs demonstrating a packaging function. Together, we provide a quantitative framework for gene- and condition-dependent RBP occupancy and stoichiometry in individual nuclear mRNPs.
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Affiliation(s)
- Ryuta Asada
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA
| | - Andrew Dominguez
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - Ben Montpetit
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA.
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4
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Moursy A, Cléry A, Gerhardy S, Betz KM, Rao S, Mazur J, Campagne S, Beusch I, Duszczyk MM, Robinson MD, Panse VG, Allain FHT. RNA recognition by Npl3p reveals U2 snRNA-binding compatible with a chaperone role during splicing. Nat Commun 2023; 14:7166. [PMID: 37935663 PMCID: PMC10630445 DOI: 10.1038/s41467-023-42962-4] [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: 08/31/2022] [Accepted: 10/27/2023] [Indexed: 11/09/2023] Open
Abstract
The conserved SR-like protein Npl3 promotes splicing of diverse pre-mRNAs. However, the RNA sequence(s) recognized by the RNA Recognition Motifs (RRM1 & RRM2) of Npl3 during the splicing reaction remain elusive. Here, we developed a split-iCRAC approach in yeast to uncover the consensus sequence bound to each RRM. High-resolution NMR structures show that RRM2 recognizes a 5´-GNGG-3´ motif leading to an unusual mille-feuille topology. These structures also reveal how RRM1 preferentially interacts with a CC-dinucleotide upstream of this motif, and how the inter-RRM linker and the region C-terminal to RRM2 contribute to cooperative RNA-binding. Structure-guided functional studies show that Npl3 genetically interacts with U2 snRNP specific factors and we provide evidence that Npl3 melts U2 snRNA stem-loop I, a prerequisite for U2/U6 duplex formation within the catalytic center of the Bact spliceosomal complex. Thus, our findings suggest an unanticipated RNA chaperoning role for Npl3 during spliceosome active site formation.
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Affiliation(s)
- Ahmed Moursy
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Antoine Cléry
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland.
| | - Stefan Gerhardy
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Sardona Therapeutics, San Francisco, CA, USA
| | - Katharina M Betz
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Sanjana Rao
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Jarosław Mazur
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Sébastien Campagne
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- ARNA laboratory, INSERM U1212, University of Bordeaux, Bordeaux, France
| | - Irene Beusch
- Department of Biology, Institute of Biochemistry, ETH Zurich, Switzerland
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | | | - Mark D Robinson
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
- Faculty of Science, University of Zurich, Zurich, Switzerland.
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5
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Chowdhury MN, Jin H. The RGG motif proteins: Interactions, functions, and regulations. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1748. [PMID: 35661420 PMCID: PMC9718894 DOI: 10.1002/wrna.1748] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 01/31/2023]
Abstract
Proteins with motifs rich in arginines and glycines were discovered decades ago and are functionally involved in a staggering range of essential processes in the cell. Versatile, specific, yet adaptable molecular interactions enabled by the unique combination of arginine and glycine, combined with multiplicity of molecular recognition conferred by repeated di-, tri-, and multiple peptide motifs, allow RGG motif proteins to interact with a broad range of proteins and nucleic acids. Furthermore, posttranslational modifications at the arginines in the motif extend the RGG protein's capacity for a fine-tuned regulation. In this review, we focus on the biochemical properties of the RGG motif, its molecular interactions with RNAs and proteins, and roles of the posttranslational modification in modulating their interactions. We discuss current knowledge of the RGG motif proteins involved in mRNA transport and translation, highlight our merging understanding of their molecular functions in translational regulation and summarize areas of research in the future critical in understanding this important family of proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Mechanisms.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Corresponding author: Phone: (217)244-9493, Fax: (217)244-5858,
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6
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Lu YY, Krebber H. Nuclear mRNA Quality Control and Cytoplasmic NMD Are Linked by the Guard Proteins Gbp2 and Hrb1. Int J Mol Sci 2021; 22:ijms222011275. [PMID: 34681934 PMCID: PMC8541090 DOI: 10.3390/ijms222011275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 12/23/2022] Open
Abstract
Pre-mRNA splicing is critical for cells, as defects in this process can lead to altered open reading frames and defective proteins, potentially causing neurodegenerative diseases and cancer. Introns are removed in the nucleus and splicing is documented by the addition of exon-junction-complexes (EJCs) at exon-exon boundaries. This “memory” of splicing events is important for the ribosome, which translates the RNAs in the cytoplasm. In case a stop codon was detected before an EJC, translation is blocked and the RNA is eliminated by the nonsense-mediated decay (NMD). In the model organism Saccharomyces cerevisiae, two guard proteins, Gbp2 and Hrb1, have been identified as nuclear quality control factors for splicing. In their absence, intron-containing mRNAs leak into the cytoplasm. Their presence retains transcripts until the process is completed and they release the mRNAs by recruitment of the export factor Mex67. On transcripts that experience splicing problems, these guard proteins recruit the nuclear RNA degradation machinery. Interestingly, they continue their quality control function on exported transcripts. They support NMD by inhibiting translation and recruiting the cytoplasmic degradation factors. In this way, they link the nuclear and cytoplasmic quality control systems. These discoveries are also intriguing for humans, as homologues of these guard proteins are present also in multicellular organisms. Here, we provide an overview of the quality control mechanisms of pre-mRNA splicing, and present Gbp2 and Hrb1, as well as their human counterparts, as important players in these pathways.
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7
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Sandhu R, Sinha A, Montpetit B. The SR-protein Npl3 is an essential component of the meiotic splicing regulatory network in Saccharomyces cerevisiae. Nucleic Acids Res 2021; 49:2552-2568. [PMID: 33577675 PMCID: PMC7969001 DOI: 10.1093/nar/gkab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 01/30/2023] Open
Abstract
The meiotic gene expression program in Saccharomyces cerevisiae involves regulated splicing of meiosis-specific genes via multiple splicing activators (e.g. Mer1, Nam8, Tgs1). Here, we show that the SR protein Npl3 is required for meiotic splicing regulation and is essential for proper execution of the meiotic cell cycle. The loss of Npl3, though not required for viability in mitosis, caused intron retention in meiosis-specific transcripts, inefficient meiotic double strand break processing and an arrest of the meiotic cell cycle. The targets of Npl3 overlapped in some cases with other splicing regulators, while also having unique target transcripts that were not shared. In the absence of Npl3, splicing defects for three transcripts (MER2, HOP2 and SAE3) were rescued by conversion of non-consensus splice sites to the consensus sequence. Methylation of Npl3 was further found to be required for splicing Mer1-dependent transcripts, indicating transcript-specific mechanisms by which Npl3 supports splicing. Together these data identify an essential function for the budding yeast SR protein Npl3 in meiosis as part of the meiotic splicing regulatory network.
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Affiliation(s)
- Rima Sandhu
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Aniketa Sinha
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
| | - Ben Montpetit
- Department of Viticulture and Enology, University of California Davis, Davis, CA, USA
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8
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Grosse S, Lu YY, Coban I, Neumann B, Krebber H. Nuclear SR-protein mediated mRNA quality control is continued in cytoplasmic nonsense-mediated decay. RNA Biol 2021; 18:1390-1407. [PMID: 33406982 PMCID: PMC8489946 DOI: 10.1080/15476286.2020.1851506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
One important task of eukaryotic cells is to translate only mRNAs that were correctly processed to prevent the production of truncated proteins, found in neurodegenerative diseases and cancer. Nuclear quality control of splicing requires the SR-like proteins Gbp2 and Hrb1 in S. cerevisiae, where they promote the degradation of faulty pre-mRNAs. Here we show that Gbp2 and Hrb1 also function in nonsense mediated decay (NMD) of spliced premature termination codon (PTC)-containing mRNAs. Our data support a model in which they are in a complex with the Upf-proteins and help to transmit the Upf1-mediated PTC recognition to the transcripts ends. Most importantly they appear to promote translation repression of spliced transcripts that contain a PTC and to finally facilitate degradation of the RNA, presumably by supporting the recruitment of the degradation factors. Therefore, they seem to control mRNA quality beyond the nuclear border and may thus be global surveillance factors. Identification of SR-proteins as general cellular surveillance factors in yeast will help to understand the complex human system in which many diseases with defects in SR-proteins or NMD are known, but the proteins were not yet recognized as general RNA surveillance factors.
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Affiliation(s)
- Sebastian Grosse
- Abteilung Für Molekulare Genetik, Institut Für Mikrobiologie Und Genetik, Göttinger Zentrum Für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Yen-Yun Lu
- Abteilung Für Molekulare Genetik, Institut Für Mikrobiologie Und Genetik, Göttinger Zentrum Für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Ivo Coban
- Abteilung Für Molekulare Genetik, Institut Für Mikrobiologie Und Genetik, Göttinger Zentrum Für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Bettina Neumann
- Abteilung Für Molekulare Genetik, Institut Für Mikrobiologie Und Genetik, Göttinger Zentrum Für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Heike Krebber
- Abteilung Für Molekulare Genetik, Institut Für Mikrobiologie Und Genetik, Göttinger Zentrum Für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
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9
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Heinrich S, Derrer CP, Lari A, Weis K, Montpetit B. Temporal and spatial regulation of mRNA export: Single particle RNA-imaging provides new tools and insights. Bioessays 2017; 39. [PMID: 28052353 DOI: 10.1002/bies.201600124] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The transport of messenger RNAs (mRNAs) from the nucleus to cytoplasm is an essential step in the gene expression program of all eukaryotes. Recent technological advances in the areas of RNA-labeling, microscopy, and sequencing are leading to novel insights about mRNA biogenesis and export. This includes quantitative single molecule imaging (SMI) of RNA molecules in live cells, which is providing knowledge of the spatial and temporal dynamics of the export process. As this information becomes available, it leads to new questions, the reinterpretation of previous findings, and revised models of mRNA export. In this review, we will briefly highlight some of these recent findings and discuss how live cell SMI approaches may be used to further our current understanding of mRNA export and gene expression.
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Affiliation(s)
| | | | - Azra Lari
- Department of Cell Biology, University of Alberta, Edmonton, Canada
| | - Karsten Weis
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Canada.,Department of Viticulture and Enology, University of California, Davis, CA, USA
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10
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Holmes RK, Tuck AC, Zhu C, Dunn-Davies HR, Kudla G, Clauder-Munster S, Granneman S, Steinmetz LM, Guthrie C, Tollervey D. Loss of the Yeast SR Protein Npl3 Alters Gene Expression Due to Transcription Readthrough. PLoS Genet 2015; 11:e1005735. [PMID: 26694144 PMCID: PMC4687934 DOI: 10.1371/journal.pgen.1005735] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/20/2015] [Indexed: 01/25/2023] Open
Abstract
Yeast Npl3 is a highly abundant, nuclear-cytoplasmic shuttling, RNA-binding protein, related to metazoan SR proteins. Reported functions of Npl3 include transcription elongation, splicing and RNA 3’ end processing. We used UV crosslinking and analysis of cDNA (CRAC) to map precise RNA binding sites, and strand-specific tiling arrays to look at the effects of loss of Npl3 on all transcripts across the genome. We found that Npl3 binds diverse RNA species, both coding and non-coding, at sites indicative of roles in both early pre-mRNA processing and 3’ end formation. Tiling arrays and RNAPII mapping data revealed 3’ extended RNAPII-transcribed RNAs in the absence of Npl3, suggesting that defects in pre-mRNA packaging events result in termination readthrough. Transcription readthrough was widespread and frequently resulted in down-regulation of neighboring genes. We conclude that the absence of Npl3 results in widespread 3' extension of transcripts with pervasive effects on gene expression. Npl3 is a yeast mRNA binding protein with many reported functions in RNA processing. We wanted to identify direct targets and therefore combined analyses of the transcriptome-wide effects of the loss of Npl3 on gene expression with UV crosslinking and bioinformatics to identify RNA-binding sites for Npl3. We found that Npl3 binds diverse sites on large numbers of transcripts, and that the loss of Npl3 results in transcriptional readthrough on many genes. One effect of this transcription readthrough is that the expression of numerous flanking genes is strongly down regulated. This underlines the importance of faithful termination for the correct regulation of gene expression. The effects of the loss of Npl3 are seen on both mRNAs and non-protein coding RNAs. These have distinct but overlapping termination mechanisms, with both classes requiring Npl3 for correct RNA packaging.
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Affiliation(s)
- Rebecca K. Holmes
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Alex C. Tuck
- FMI Basel, Basel, Switzerland
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | | | - Hywel R. Dunn-Davies
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Grzegorz Kudla
- The Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, Scotland, United Kingdom
| | | | - Sander Granneman
- SynthSys, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | | | - Christine Guthrie
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, United States of America
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * E-mail:
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11
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Celik A, Kervestin S, Jacobson A. NMD: At the crossroads between translation termination and ribosome recycling. Biochimie 2014; 114:2-9. [PMID: 25446649 DOI: 10.1016/j.biochi.2014.10.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 10/27/2014] [Indexed: 10/24/2022]
Abstract
Nonsense-mediated mRNA decay (NMD) is one of three regulatory mechanisms that monitor the cytoplasm for aberrant mRNAs. NMD is usually triggered by premature translation termination codons that arise from mutations, transcription errors, or inefficient splicing, but which also occur in transcripts with alternately spliced isoforms or upstream open reading frames, or in the context of long 3'-UTRs. This surveillance pathway requires detection of the nonsense codon by the eukaryotic release factors (eRF1 and eRF3) and the activities of the Upf proteins, but the exact mechanism by which a nonsense codon is recognized as premature, and the individual roles of the Upf proteins, are poorly understood. In this review, we highlight important differences between premature and normal termination. Based on our current understanding of normal termination and ribosome recycling, we propose a similar mechanism for premature termination events that includes a role for the Upf proteins. In this model, the Upf proteins not only target the mRNA and nascent peptide for degradation, but also assume the role of recycling factors and rescue a ribosome stalled at a premature nonsense codon. The ATPase and helicase activities of Upf1, with the help of Upf2 and Upf3, are thus thought to be the catalytic force in ribosome subunit dissociation and ribosome recycling at an otherwise poorly dissociable termination event. While this model is somewhat speculative, it provides a unified vision for current data and a direction for future research.
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Affiliation(s)
- Alper Celik
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01655-0122, USA
| | - Stephanie Kervestin
- CNRS FRE3630 Associated with Université Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Allan Jacobson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01655-0122, USA.
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12
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Wang L, Jiang N, Wang L, Fang O, Leach LJ, Hu X, Luo Z. 3' Untranslated regions mediate transcriptional interference between convergent genes both locally and ectopically in Saccharomyces cerevisiae. PLoS Genet 2014; 10:e1004021. [PMID: 24465217 PMCID: PMC3900390 DOI: 10.1371/journal.pgen.1004021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 10/28/2013] [Indexed: 11/18/2022] Open
Abstract
Paired sense and antisense (S/AS) genes located in cis represent a structural feature common to the genomes of both prokaryotes and eukaryotes, and produce partially complementary transcripts. We used published genome and transcriptome sequence data and found that over 20% of genes (645 pairs) in the budding yeast Saccharomyces cerevisiae genome are arranged in convergent pairs with overlapping 3'-UTRs. Using published microarray transcriptome data from the standard laboratory strain of S. cerevisiae, our analysis revealed that expression levels of convergent pairs are significantly negatively correlated across a broad range of environments. This implies an important role for convergent genes in the regulation of gene expression, which may compensate for the absence of RNA-dependent mechanisms such as micro RNAs in budding yeast. We selected four representative convergent gene pairs and used expression assays in wild type yeast and its genetically modified strains to explore the underlying patterns of gene expression. Results showed that convergent genes are reciprocally regulated in yeast populations and in single cells, whereby an increase in expression of one gene produces a decrease in the expression of the other, and vice-versa. Time course analysis of the cell cycle illustrated the functional significance of this relationship for the three pairs with relevant functional roles. Furthermore, a series of genetic modifications revealed that the 3'-UTR sequence plays an essential causal role in mediating transcriptional interference, which requires neither the sequence of the open reading frame nor the translation of fully functional proteins. More importantly, transcriptional interference persisted even when one of the convergent genes was expressed ectopically (in trans) and therefore does not depend on the cis arrangement of convergent genes; we conclude that the mechanism of transcriptional interference cannot be explained by the transcriptional collision model, which postulates a clash between simultaneous transcriptional processes occurring on opposite DNA strands.
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Affiliation(s)
- Luwen Wang
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
| | - Ning Jiang
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
| | - Lin Wang
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
| | - Ou Fang
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
| | - Lindsey J. Leach
- School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
| | - Xiaohua Hu
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
- * E-mail: (XH); (ZL)
| | - Zewei Luo
- Laboratory of Population & Quantitative Genetics, Institute of Genetics and Biostatistics, SKLG, School of Life Sciences, Fudan University, Shanghai, China
- School of Biosciences, The University of Birmingham, Birmingham, United Kingdom
- * E-mail: (XH); (ZL)
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13
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Corden JL. RNA polymerase II C-terminal domain: Tethering transcription to transcript and template. Chem Rev 2013; 113:8423-55. [PMID: 24040939 PMCID: PMC3988834 DOI: 10.1021/cr400158h] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jeffry L Corden
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine , 725 North Wolfe Street, Baltimore Maryland 21205, United States
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14
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Lasalde C, Rivera AV, León AJ, González-Feliciano JA, Estrella LA, Rodríguez-Cruz EN, Correa ME, Cajigas IJ, Bracho DP, Vega IE, Wilkinson MF, González CI. Identification and functional analysis of novel phosphorylation sites in the RNA surveillance protein Upf1. Nucleic Acids Res 2013; 42:1916-29. [PMID: 24198248 PMCID: PMC3919615 DOI: 10.1093/nar/gkt1049] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
One third of inherited genetic diseases are caused by mRNAs harboring premature termination codons as a result of nonsense mutations. These aberrant mRNAs are degraded by the Nonsense-Mediated mRNA Decay (NMD) pathway. A central component of the NMD pathway is Upf1, an RNA-dependent ATPase and helicase. Upf1 is a known phosphorylated protein, but only portions of this large protein have been examined for phosphorylation sites and the functional relevance of its phosphorylation has not been elucidated in Saccharomyces cerevisiae. Using tandem mass spectrometry analyses, we report the identification of 11 putative phosphorylated sites in S. cerevisiae Upf1. Five of these phosphorylated residues are located within the ATPase and helicase domains and are conserved in higher eukaryotes, suggesting a biological significance for their phosphorylation. Indeed, functional analysis demonstrated that a small carboxy-terminal motif harboring at least three phosphorylated amino acids is important for three Upf1 functions: ATPase activity, NMD activity and the ability to promote translation termination efficiency. We provide evidence that two tyrosines within this phospho-motif (Y-738 and Y-742) act redundantly to promote ATP hydrolysis, NMD efficiency and translation termination fidelity.
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Affiliation(s)
- Clarivel Lasalde
- Department of Biology, University of Puerto Rico-Río Piedras Campus, San Juan, PR, Department of Reproductive Medicine, University of California, San Diego, CA, Department of Biochemistry, University of Puerto Rico-Medical Sciences Campus, San Juan, PR and Molecular Sciences Research Building, San Juan, PR
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15
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Abstract
Although most mRNA molecules derived from protein-coding genes are destined to be translated into functional polypeptides, some are eliminated by cellular quality control pathways that collectively perform the task of mRNA surveillance. In the nonsense-mediated decay (NMD) pathway premature translation termination promotes the recruitment of a set of factors that destabilize a targeted mRNA. The same factors also seem to have key roles in repressing the translation of the mRNA, dissociating its terminating ribosome and messenger ribonucleoproteins (mRNPs), promoting the degradation of its truncated polypeptide product and possibly even feeding back to the site of transcription to interfere with splicing of the primary transcript.
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16
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Lee-Soety JY, Jones J, MacGibeny MA, Remaly EC, Daniels L, Ito A, Jean J, Radecki H, Spencer S. Yeast hnRNP-related proteins contribute to the maintenance of telomeres. Biochem Biophys Res Commun 2012; 426:12-7. [PMID: 22902537 DOI: 10.1016/j.bbrc.2012.07.144] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 07/26/2012] [Indexed: 01/06/2023]
Abstract
Telomeres protect the ends of linear chromosomes, which if eroded to a critical length can become uncapped and lead to replicative senescence. Telomerase maintains telomere length in some cells, but inappropriate expression facilitates the immortality of cancer cells. Recently, proteins involved in RNA processing and ribosome assembly, such as hnRNP (heterogeneous nuclear ribonucleoprotein) A1, have been found to participate in telomere maintenance in mammals. The Saccharomyces cerevisiae protein Npl3 shares significant amino acid sequence similarities with hnRNP A1. We found that deleting NPL3 accelerated the senescence of telomerase null cells. The highly conserved RNA recognition motifs (RRM) in Npl3 appear to be important for preventing faster senescence. Npl3 preferentially binds telomere sequences in vitro, suggesting that Npl3 may affect telomeres directly. Despite similarities between the two proteins, human hnRNP A1 is unable to complement the lack of Npl3 to rescue accelerated senescence in tlc1 npl3 cells. Deletion of CBC2, which encodes another hnRNP-related protein that associates with Npl3, also accelerates senescence. Potential mechanisms by which hnRNP-related proteins maintain telomeres are discussed.
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17
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Torabi N, Kruglyak L. Genetic basis of hidden phenotypic variation revealed by increased translational readthrough in yeast. PLoS Genet 2012; 8:e1002546. [PMID: 22396662 PMCID: PMC3291563 DOI: 10.1371/journal.pgen.1002546] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 12/28/2011] [Indexed: 01/07/2023] Open
Abstract
Eukaryotic release factors 1 and 3, encoded by SUP45 and SUP35, respectively, in Saccharomyces cerevisiae, are required for translation termination. Recent studies have shown that, besides these two key factors, several genetic and epigenetic mechanisms modulate the efficiency of translation termination. These mechanisms, through modifying translation termination fidelity, were shown to affect various cellular processes, such as mRNA degradation, and in some cases could confer a beneficial phenotype to the cell. The most studied example of such a mechanism is [PSI+], the prion conformation of Sup35p, which can have pleiotropic effects on growth that vary among different yeast strains. However, genetic loci underlying such readthrough-dependent, background-specific phenotypes have yet to be identified. Here, we used sup35C653R, a partial loss-of-function allele of the SUP35 previously shown to increase readthrough of stop codons and recapitulate some [PSI+]-dependent phenotypes, to study the genetic basis of phenotypes revealed by increased translational readthrough in two divergent yeast strains: BY4724 (a laboratory strain) and RM11_1a (a wine strain). We first identified growth conditions in which increased readthrough of stop codons by sup35C653R resulted in different growth responses between these two strains. We then used a recently developed linkage mapping technique, extreme QTL mapping (X-QTL), to identify readthrough-dependent loci for the observed growth differences. We further showed that variation in SKY1, an SR protein kinase, underlies a readthrough-dependent locus observed for growth on diamide and hydrogen peroxide. We found that the allelic state of SKY1 interacts with readthrough level and the genetic background to determine growth rate in these two conditions. Proper termination is an important step in a successful mRNA translation event. Many factors, employing genetic and epigenetic mechanisms, are involved in modifying translation termination efficiency in the budding yeast, Saccharomyces cerevisiae. [PSI+], the prion conformation of Sup35p, one of the translation termination factors in yeast, provides an example of such mechanisms. [PSI+] increases readthrough of stop codons. This has the potential to unveil hidden genetic variation that may enhance growth in some yeast strains in certain environments. The specific details of readthrough-dependent phenotypes, however, have remained poorly understood. Here, we used a partial loss-of-function allele of SUP35, which increases readthrough of stop codons, and a recently developed linkage mapping technique, X-QTL, to map loci underlying readthrough-dependent growth phenotypes in two divergent yeast strains, BY (a laboratory strain) and RM (a wine strain). We found that readthrough-dependent growth phenotypes are often complex, with multiple loci influencing growth. We also showed that variants in the gene SKY1 underlie one of the loci detected for readthrough-dependent growth phenotypes in the presence of two chemicals that induce oxidative stress.
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Affiliation(s)
- Noorossadat Torabi
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Leonid Kruglyak
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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18
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Garre E, Romero-Santacreu L, De Clercq N, Blasco-Angulo N, Sunnerhagen P, Alepuz P. Yeast mRNA cap-binding protein Cbc1/Sto1 is necessary for the rapid reprogramming of translation after hyperosmotic shock. Mol Biol Cell 2011; 23:137-50. [PMID: 22072789 PMCID: PMC3248893 DOI: 10.1091/mbc.e11-05-0419] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Global translation is inhibited in Saccharomyces cerevisiae cells under osmotic stress; nonetheless, osmostress-protective proteins are synthesized. We found that translation mediated by the mRNA cap-binding protein Cbc1 is stress-resistant and necessary for the rapid translation of osmostress-protective proteins under osmotic stress. In response to osmotic stress, global translation is inhibited, but the mRNAs encoding stress-protective proteins are selectively translated to allow cell survival. To date, the mechanisms and factors involved in the specific translation of osmostress-responsive genes in Saccharomyces cerevisiae are unknown. We find that the mRNA cap-binding protein Cbc1 is important for yeast survival under osmotic stress. Our results provide new evidence supporting a role of Cbc1 in translation initiation. Cbc1 associates with polysomes, while the deletion of the CBC1 gene causes hypersensitivity to the translation inhibitor cycloheximide and yields synthetic “sickness” in cells with limiting amounts of translation initiator factor eIF4E. In cbc1Δ mutants, translation drops sharply under osmotic stress, the subsequent reinitiation of translation is retarded, and “processing bodies” containing untranslating mRNAs remain for long periods. Furthermore, osmostress-responsive mRNAs are transcriptionally induced after osmotic stress in cbc1Δ cells, but their rapid association with polysomes is delayed. However, in cells containing a thermosensitive eIF4E allele, their inability to grow at 37ºC is suppressed by hyperosmosis, and Cbc1 relocalizes from nucleus to cytoplasm. These data support a model in which eIF4E-translation could be stress-sensitive, while Cbc1-mediated translation is necessary for the rapid translation of osmostress-protective proteins under osmotic stress.
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Affiliation(s)
- Elena Garre
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universitat de València, Burjassot, Valencia, Spain
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19
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Abstract
The cell nucleus is an intricate organelle that coordinates multiple activities that are associated with DNA replication and gene expression. In all eukaryotes, it stores the genetic information and the machineries that control the production of mature and export-competent messenger ribonucleoproteins (mRNPs), a multistep process that is regulated in a spatial and temporal manner. Recent studies suggest that post-translational modifications play a part in coordinating the co-transcriptional assembly, remodelling and export of mRNP complexes through nuclear pores, adding a new level of regulation to the process of gene expression.
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Rispal D, Henri J, van Tilbeurgh H, Graille M, Séraphin B. Structural and functional analysis of Nro1/Ett1: a protein involved in translation termination in S. cerevisiae and in O2-mediated gene control in S. pombe. RNA (NEW YORK, N.Y.) 2011; 17:1213-1224. [PMID: 21610214 PMCID: PMC3138559 DOI: 10.1261/rna.2697111] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 04/01/2011] [Indexed: 05/30/2023]
Abstract
In Saccharomyces cerevisiae, the putative 2-OG-Fe(II) dioxygenase Tpa1 and its partner Ett1 have been shown to impact mRNA decay and translation. Hence, inactivation of these factors was shown to influence stop codon read-though. In addition, Tpa1 represses, by an unknown mechanism, genes regulated by Hap1, a transcription factor involved in the response to levels of heme and O(2). The Schizosaccharomyces pombe orthologs of Tpa1 and Ett1, Ofd1, and its partner Nro1, respectively, have been shown to regulate the stability of the Sre1 transcription factor in response to oxygen levels. To gain insight into the function of Nro1/Ett1, we have solved the crystal structure of the S. pombe Nro1 protein deleted of its 54 N-terminal residues. Nro1 unexpectedly adopts a Tetratrico Peptide Repeat (TPR) fold, a motif often responsible for protein or peptide binding. Two ligands, a sulfate ion and an unknown molecule, interact with a cluster of highly conserved amino acids on the protein surface. Mutation of these residues demonstrates that these ligand binding sites are essential for Ett1 function in S. cerevisiae, as investigated by assaying for efficient translation termination.
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Affiliation(s)
- Delphine Rispal
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR7104, Inserm U964, and Université de Strasbourg, Strasbourg, Illkirch F-67000, France
- Centre de Génétique Moléculaire (CGM), CNRS, F-91198 Gif-sur-Yvette Cedex, France
| | - Julien Henri
- Equipe “Fonction et Architecture des Assemblages Macromoléculaires”, IBBMC (Institut de Biochimie et Biophysique Moléculaire et Cellulaire), CNRS, UMR8619, Bat 430, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Herman van Tilbeurgh
- Equipe “Fonction et Architecture des Assemblages Macromoléculaires”, IBBMC (Institut de Biochimie et Biophysique Moléculaire et Cellulaire), CNRS, UMR8619, Bat 430, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Marc Graille
- Equipe “Fonction et Architecture des Assemblages Macromoléculaires”, IBBMC (Institut de Biochimie et Biophysique Moléculaire et Cellulaire), CNRS, UMR8619, Bat 430, Université Paris Sud, F-91405 Orsay Cedex, France
| | - Bertrand Séraphin
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR7104, Inserm U964, and Université de Strasbourg, Strasbourg, Illkirch F-67000, France
- Centre de Génétique Moléculaire (CGM), CNRS, F-91198 Gif-sur-Yvette Cedex, France
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21
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Current awareness on yeast. Yeast 2010. [DOI: 10.1002/yea.1717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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