1
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Enders L, Siklos M, Borggräfe J, Gaussmann S, Koren A, Malik M, Tomek T, Schuster M, Reiniš J, Hahn E, Rukavina A, Reicher A, Casteels T, Bock C, Winter GE, Hannich JT, Sattler M, Kubicek S. Pharmacological perturbation of the phase-separating protein SMNDC1. Nat Commun 2023; 14:4504. [PMID: 37587144 PMCID: PMC10432564 DOI: 10.1038/s41467-023-40124-0] [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: 10/19/2022] [Accepted: 07/13/2023] [Indexed: 08/18/2023] Open
Abstract
SMNDC1 is a Tudor domain protein that recognizes di-methylated arginines and controls gene expression as an essential splicing factor. Here, we study the specific contributions of the SMNDC1 Tudor domain to protein-protein interactions, subcellular localization, and molecular function. To perturb the protein function in cells, we develop small molecule inhibitors targeting the dimethylarginine binding pocket of the SMNDC1 Tudor domain. We find that SMNDC1 localizes to phase-separated membraneless organelles that partially overlap with nuclear speckles. This condensation behavior is driven by the unstructured C-terminal region of SMNDC1, depends on RNA interaction and can be recapitulated in vitro. Inhibitors of the protein's Tudor domain drastically alter protein-protein interactions and subcellular localization, causing splicing changes for SMNDC1-dependent genes. These compounds will enable further pharmacological studies on the role of SMNDC1 in the regulation of nuclear condensates, gene regulation and cell identity.
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Affiliation(s)
- Lennart Enders
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Marton Siklos
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Jan Borggräfe
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Neuherberg, 85764, München, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Garching, 85748, München, Germany
| | - Stefan Gaussmann
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Neuherberg, 85764, München, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Garching, 85748, München, Germany
| | - Anna Koren
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Monika Malik
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Tatjana Tomek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Michael Schuster
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Jiří Reiniš
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Elisa Hahn
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Andrea Rukavina
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Andreas Reicher
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Tamara Casteels
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
- Sloan Kettering Institute, 1275 York Avenue, New York, NY, 10065, USA
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
- Medical University of Vienna, Institute of Artificial Intelligence, Center for Medical Data Science, Währinger Straße 25a, 1090, Vienna, Austria
| | - Georg E Winter
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - J Thomas Hannich
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria
| | - Michael Sattler
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Neuherberg, 85764, München, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Garching, 85748, München, Germany
| | - Stefan Kubicek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090, Vienna, Austria.
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2
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Wolin E, Guo JK, Blanco MR, Perez AA, Goronzy IN, Abdou AA, Gorhe D, Guttman M, Jovanovic M. SPIDR: a highly multiplexed method for mapping RNA-protein interactions uncovers a potential mechanism for selective translational suppression upon cellular stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543769. [PMID: 37333139 PMCID: PMC10274648 DOI: 10.1101/2023.06.05.543769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
RNA binding proteins (RBPs) play crucial roles in regulating every stage of the mRNA life cycle and mediating non-coding RNA functions. Despite their importance, the specific roles of most RBPs remain unexplored because we do not know what specific RNAs most RBPs bind. Current methods, such as crosslinking and immunoprecipitation followed by sequencing (CLIP-seq), have expanded our knowledge of RBP-RNA interactions but are generally limited by their ability to map only one RBP at a time. To address this limitation, we developed SPIDR (Split and Pool Identification of RBP targets), a massively multiplexed method to simultaneously profile global RNA binding sites of dozens to hundreds of RBPs in a single experiment. SPIDR employs split-pool barcoding coupled with antibody-bead barcoding to increase the throughput of current CLIP methods by two orders of magnitude. SPIDR reliably identifies precise, single-nucleotide RNA binding sites for diverse classes of RBPs simultaneously. Using SPIDR, we explored changes in RBP binding upon mTOR inhibition and identified that 4EBP1 acts as a dynamic RBP that selectively binds to 5'-untranslated regions of specific translationally repressed mRNAs only upon mTOR inhibition. This observation provides a potential mechanism to explain the specificity of translational regulation controlled by mTOR signaling. SPIDR has the potential to revolutionize our understanding of RNA biology and both transcriptional and post-transcriptional gene regulation by enabling rapid, de novo discovery of RNA-protein interactions at an unprecedented scale.
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Affiliation(s)
- Erica Wolin
- Department of Biological Sciences, Columbia University, New York City, New York 10027, USA
| | - Jimmy K. Guo
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Mario R. Blanco
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
| | - Andrew A. Perez
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
| | - Isabel N. Goronzy
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
| | - Ahmed A. Abdou
- Department of Biological Sciences, Columbia University, New York City, New York 10027, USA
| | - Darvesh Gorhe
- Department of Biological Sciences, Columbia University, New York City, New York 10027, USA
| | - Mitchell Guttman
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena CA 91125, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York City, New York 10027, USA
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3
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Wang Y, Bedford MT. Effectors and effects of arginine methylation. Biochem Soc Trans 2023; 51:725-734. [PMID: 37013969 PMCID: PMC10212539 DOI: 10.1042/bst20221147] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 04/05/2023]
Abstract
Arginine methylation is a ubiquitous and relatively stable post-translational modification (PTM) that occurs in three types: monomethylarginine (MMA), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA). Methylarginine marks are catalyzed by members of the protein arginine methyltransferases (PRMTs) family of enzymes. Substrates for arginine methylation are found in most cellular compartments, with RNA-binding proteins forming the majority of PRMT targets. Arginine methylation often occurs in intrinsically disordered regions of proteins, which impacts biological processes like protein-protein interactions and phase separation, to modulate gene transcription, mRNA splicing and signal transduction. With regards to protein-protein interactions, the major 'readers' of methylarginine marks are Tudor domain-containing proteins, although additional domain types and unique protein folds have also recently been identified as methylarginine readers. Here, we will assess the current 'state-of-the-art' in the arginine methylation reader field. We will focus on the biological functions of the Tudor domain-containing methylarginine readers and address other domains and complexes that sense methylarginine marks.
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Affiliation(s)
- Yalong Wang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, U.S.A
| | - Mark T. Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, U.S.A
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4
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Casteels T, Bajew S, Reiniš J, Enders L, Schuster M, Fontaine F, Müller AC, Wagner BK, Bock C, Kubicek S. SMNDC1 links chromatin remodeling and splicing to regulate pancreatic hormone expression. Cell Rep 2022; 40:111288. [PMID: 36044849 DOI: 10.1016/j.celrep.2022.111288] [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: 09/03/2021] [Revised: 04/06/2022] [Accepted: 08/09/2022] [Indexed: 11/28/2022] Open
Abstract
Insulin expression is primarily restricted to the pancreatic β cells, which are physically or functionally depleted in diabetes. Identifying targetable pathways repressing insulin in non-β cells, particularly in the developmentally related glucagon-secreting α cells, is an important aim of regenerative medicine. Here, we perform an RNA interference screen in a murine α cell line to identify silencers of insulin expression. We discover that knockdown of the splicing factor Smndc1 triggers a global repression of α cell gene-expression programs in favor of increased β cell markers. Mechanistically, Smndc1 knockdown upregulates the β cell transcription factor Pdx1 by modulating the activities of the BAF and Atrx chromatin remodeling complexes. SMNDC1's repressive role is conserved in human pancreatic islets, its loss triggering enhanced insulin secretion and PDX1 expression. Our study identifies Smndc1 as a key factor connecting splicing and chromatin remodeling to the control of insulin expression in human and mouse islet cells.
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Affiliation(s)
- Tamara Casteels
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - Simon Bajew
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Carrer del Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Carrer del Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Jiří Reiniš
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - Lennart Enders
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - Michael Schuster
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - Frédéric Fontaine
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | - André C Müller
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria
| | | | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria; Medical University of Vienna, Center for Medical Statistics, Informatics, and Intelligent Systems, Institute of Artificial Intelligence, 1090 Vienna, Austria
| | - Stefan Kubicek
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Lazarettgasse 14, 1090 Vienna, Austria.
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5
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Thomas JD, Polaski JT, Feng Q, De Neef EJ, Hoppe ER, McSharry MV, Pangallo J, Gabel AM, Belleville AE, Watson J, Nkinsi NT, Berger AH, Bradley RK. RNA isoform screens uncover the essentiality and tumor-suppressor activity of ultraconserved poison exons. Nat Genet 2020; 52:84-94. [PMID: 31911676 PMCID: PMC6962552 DOI: 10.1038/s41588-019-0555-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 11/21/2019] [Indexed: 12/30/2022]
Abstract
While RNA-seq has enabled comprehensive quantification of alternative splicing, no correspondingly high-throughput assay exists for functionally interrogating individual isoforms. We describe pgFARM (paired guide RNAs for alternative exon removal), a CRISPR-Cas9-based method to manipulate isoforms independent of gene inactivation. This approach enabled rapid suppression of exon recognition in polyclonal settings to identify functional roles for individual exons, such as an SMNDC1 cassette exon that regulates pan-cancer intron retention. We generalized this method to a pooled screen to measure the functional relevance of 'poison' cassette exons, which disrupt their host genes' reading frames yet are frequently ultraconserved. Many poison exons were essential for the growth of both cultured cells and lung adenocarcinoma xenografts, while a subset had clinically relevant tumor-suppressor activity. The essentiality and cancer relevance of poison exons are likely to contribute to their unusually high conservation and contrast with the dispensability of other ultraconserved elements for viability.
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Affiliation(s)
- James D Thomas
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jacob T Polaski
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Qing Feng
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Emma J De Neef
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Emma R Hoppe
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Maria V McSharry
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Joseph Pangallo
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Austin M Gabel
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Andrea E Belleville
- Medical Scientist Training Program, University of Washington, Seattle, WA, USA
| | - Jacqueline Watson
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Naomi T Nkinsi
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Alice H Berger
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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6
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Zhang D, Yang JF, Gao B, Liu TY, Hao GF, Yang GF, Fu LJ, Chen MX, Zhang J. Identification, evolution and alternative splicing profile analysis of the splicing factor 30 (SPF30) in plant species. PLANTA 2019; 249:1997-2014. [PMID: 30904945 DOI: 10.1007/s00425-019-03146-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
The work offers a comprehensive evaluation on the phylogenetics and conservation of splicing patterns of the plant SPF30 splicing factor gene family. In eukaryotes, one pre-mRNA can generate multiple mRNA transcripts by alternative splicing (AS), which expands transcriptome and proteome diversity. Splicing factor 30 (SPF30), also known as survival motor neuron domain containing protein 1 (SMNDC1), is a spliceosomal protein that plays an essential role in spliceosomal assembly. Although SPF30 genes have been well characterised in human and yeast, little is known about their homologues in plants. Here, we report the genome-wide identification and phylogenetic analysis of SPF30 genes in the plant kingdom. In total, 82 SPF30 genes were found in 64 plant species from algae to land plants. Alternative transcripts were found in many SPF30 genes and splicing profile analysis revealed that the second intron in SPF30 genome is frequently associated with AS events and contributed to the birth of novel exons in a few SPF30 members. In addition, different conserved sequences were observed at these putative splice sites among moss, monocots and dicots, respectively. Our findings will facilitate further functional characterization of plant SPF30 genes as putative splicing factors.
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Affiliation(s)
- Di Zhang
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China
| | - Jing-Fang Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Bei Gao
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tie-Yuan Liu
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ge-Fei Hao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, China
| | - Li-Jun Fu
- Fujian Provincial Key Laboratory of Ecology-Toxicological Effects & Control for Emerging Contaminants, Putian University, Putian, 351100, Fujian, People's Republic of China
| | - Mo-Xian Chen
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong.
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
| | - Jianhua Zhang
- Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
- Department of Biology, Hong Kong Baptist University and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong.
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7
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McAninch DS, Heinaman AM, Lang CN, Moss KR, Bassell GJ, Rita Mihailescu M, Evans TL. Fragile X mental retardation protein recognizes a G quadruplex structure within the survival motor neuron domain containing 1 mRNA 5'-UTR. MOLECULAR BIOSYSTEMS 2017; 13:1448-1457. [PMID: 28612854 PMCID: PMC5544254 DOI: 10.1039/c7mb00070g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
G quadruplex structures have been predicted by bioinformatics to form in the 5'- and 3'-untranslated regions (UTRs) of several thousand mature mRNAs and are believed to play a role in translation regulation. Elucidation of these roles has primarily been focused on the 3'-UTR, with limited focus on characterizing the G quadruplex structures and functions in the 5'-UTR. Investigation of the affinity and specificity of RNA binding proteins for 5'-UTR G quadruplexes and the resulting regulatory effects have also been limited. Among the mRNAs predicted to form a G quadruplex structure within the 5'-UTR is the survival motor neuron domain containing 1 (SMNDC1) mRNA, encoding a protein that is critical to the spliceosome. Additionally, this mRNA has been identified as a potential target of the fragile X mental retardation protein (FMRP), whose loss of expression leads to fragile X syndrome. FMRP is an RNA binding protein involved in translation regulation that has been shown to bind mRNA targets that form G quadruplex structures. In this study we have used biophysical methods to investigate G quadruplex formation in the 5'-UTR of SMNDC1 mRNA and analyzed its interactions with FMRP. Our results show that SMNDC1 mRNA 5'-UTR forms an intramolecular, parallel G quadruplex structure comprised of three G quartet planes, which is bound specifically by FMRP both in vitro and in mouse brain lysates. These findings suggest a model by which FMRP might regulate the translation of a subset of its mRNA targets by recognizing the G quadruplex structure present in their 5'-UTR, and affecting their accessibility by the protein synthesis machinery.
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Affiliation(s)
- Damian S McAninch
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, USA.
| | - Ashley M Heinaman
- Department of Chemistry, University of Pittsburgh at Johnstown, Johnstown, Pennsylvania 15904, USA
| | - Cara N Lang
- Department of Chemistry, University of Pittsburgh at Johnstown, Johnstown, Pennsylvania 15904, USA
| | - Kathryn R Moss
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Mihaela Rita Mihailescu
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, USA.
| | - Timothy L Evans
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, Pennsylvania 15282, USA. and Department of Chemistry, University of Pittsburgh at Johnstown, Johnstown, Pennsylvania 15904, USA
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8
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Sidarovich A, Will CL, Anokhina MM, Ceballos J, Sievers S, Agafonov DE, Samatov T, Bao P, Kastner B, Urlaub H, Waldmann H, Lührmann R. Identification of a small molecule inhibitor that stalls splicing at an early step of spliceosome activation. eLife 2017; 6. [PMID: 28300534 PMCID: PMC5354520 DOI: 10.7554/elife.23533] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/26/2017] [Indexed: 11/13/2022] Open
Abstract
Small molecule inhibitors of pre-mRNA splicing are important tools for identifying new spliceosome assembly intermediates, allowing a finer dissection of spliceosome dynamics and function. Here, we identified a small molecule that inhibits human pre-mRNA splicing at an intermediate stage during conversion of pre-catalytic spliceosomal B complexes into activated Bact complexes. Characterization of the stalled complexes (designated B028) revealed that U4/U6 snRNP proteins are released during activation before the U6 Lsm and B-specific proteins, and before recruitment and/or stable incorporation of Prp19/CDC5L complex and other Bact complex proteins. The U2/U6 RNA network in B028 complexes differs from that of the Bact complex, consistent with the idea that the catalytic RNA core forms stepwise during the B to Bact transition and is likely stabilized by the Prp19/CDC5L complex and related proteins. Taken together, our data provide new insights into the RNP rearrangements and extensive exchange of proteins that occurs during spliceosome activation. DOI:http://dx.doi.org/10.7554/eLife.23533.001
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Affiliation(s)
- Anzhalika Sidarovich
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Maria M Anokhina
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Javier Ceballos
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sonja Sievers
- Compound Management and Screening Center, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Dmitry E Agafonov
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Timur Samatov
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Penghui Bao
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Berthold Kastner
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytics Group, Institute for Clinical Chemistry Göttingen, University Medical Center, Göttingen, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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9
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Boesler C, Rigo N, Anokhina MM, Tauchert MJ, Agafonov DE, Kastner B, Urlaub H, Ficner R, Will CL, Lührmann R. A spliceosome intermediate with loosely associated tri-snRNP accumulates in the absence of Prp28 ATPase activity. Nat Commun 2016; 7:11997. [PMID: 27377154 PMCID: PMC4935976 DOI: 10.1038/ncomms11997] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 05/20/2016] [Indexed: 11/17/2022] Open
Abstract
The precise role of the spliceosomal DEAD-box protein Prp28 in higher eukaryotes remains unclear. We show that stable tri-snRNP association during pre-catalytic spliceosomal B complex formation is blocked by a dominant-negative hPrp28 mutant lacking ATPase activity. Complexes formed in the presence of ATPase-deficient hPrp28 represent a novel assembly intermediate, the pre-B complex, that contains U1, U2 and loosely associated tri-snRNP and is stalled before disruption of the U1/5′ss base pairing interaction, consistent with a role for hPrp28 in the latter. Pre-B and B complexes differ structurally, indicating that stable tri-snRNP integration is accompanied by substantial rearrangements in the spliceosome. Disruption of the U1/5′ss interaction alone is not sufficient to bypass the block by ATPase-deficient hPrp28, suggesting hPrp28 has an additional function at this stage of splicing. Our data provide new insights into the function of Prp28 in higher eukaryotes, and the requirements for stable tri-snRNP binding during B complex formation. The assembly of the splicesome involves several distinct stages that require the sequential action of DExD/H-box RNA helicases. Here, the authors uncover a new intermediate, the pre-B complex, that accumulates in the presence of an inactive form of the DEAD-box protein Prp28.
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Affiliation(s)
- Carsten Boesler
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Norbert Rigo
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Maria M Anokhina
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Marcel J Tauchert
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Dmitry E Agafonov
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Berthold Kastner
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, D-37075 Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
| | - Cindy L Will
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
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10
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Van Nostrand EL, Pratt GA, Shishkin AA, Gelboin-Burkhart C, Fang MY, Sundararaman B, Blue SM, Nguyen TB, Surka C, Elkins K, Stanton R, Rigo F, Guttman M, Yeo GW. Robust transcriptome-wide discovery of RNA-binding protein binding sites with enhanced CLIP (eCLIP). Nat Methods 2016; 13:508-14. [PMID: 27018577 PMCID: PMC4887338 DOI: 10.1038/nmeth.3810] [Citation(s) in RCA: 818] [Impact Index Per Article: 102.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/16/2016] [Indexed: 12/26/2022]
Abstract
As RNA binding proteins (RBPs) play essential roles in cellular physiology by interacting with target RNAs, binding site identification by UV-crosslinking and immunoprecipitation (CLIP) of ribonucleoprotein complexes is critical to understanding RBP function. However, current CLIP protocols are technically demanding and yield low complexity libraries with high experimental failure rates. We have developed an enhanced CLIP (eCLIP) protocol that decreases requisite amplification by ~1,000-fold, decreasing discarded PCR duplicate reads by ~60% while maintaining single-nucleotide binding resolution. By simplifying the generation of paired IgG and size-matched input controls, eCLIP improves specificity in discovery of authentic binding sites. We generated 102 eCLIP experiments for 73 diverse RBPs in HepG2 and K562 cells (available at https://www.encodeproject.org), demonstrating that eCLIP enables large-scale and robust profiling, with amplification and sample requirements similar to ChIP-seq. eCLIP enables integrative analysis of diverse RBPs to reveal factor-specific profiles, common artifacts for CLIP and RNA-centric perspectives of RBP activity.
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Affiliation(s)
- Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Gabriel A Pratt
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA.,Bioinformatics and Systems Biology Graduate Program, University of California at San Diego, La Jolla, California, USA
| | - Alexander A Shishkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Chelsea Gelboin-Burkhart
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Mark Y Fang
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Balaji Sundararaman
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Steven M Blue
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Thai B Nguyen
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Christine Surka
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Keri Elkins
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Rebecca Stanton
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California, USA.,Stem Cell Program, University of California at San Diego, La Jolla, California, USA.,Institute for Genomic Medicine, University of California at San Diego, La Jolla, California, USA.,Bioinformatics and Systems Biology Graduate Program, University of California at San Diego, La Jolla, California, USA.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Molecular Engineering Laboratory, A*STAR, Singapore
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11
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orthoFind Facilitates the Discovery of Homologous and Orthologous Proteins. PLoS One 2015; 10:e0143906. [PMID: 26624019 PMCID: PMC4666658 DOI: 10.1371/journal.pone.0143906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/07/2015] [Indexed: 11/19/2022] Open
Abstract
Finding homologous and orthologous protein sequences is often the first step in evolutionary studies, annotation projects, and experiments of functional complementation. Despite all currently available computational tools, there is a requirement for easy-to-use tools that provide functional information. Here, a new web application called orthoFind is presented, which allows a quick search for homologous and orthologous proteins given one or more query sequences, allowing a recurrent and exhaustive search against reference proteomes, and being able to include user databases. It addresses the protein multidomain problem, searching for homologs with the same domain architecture, and gives a simple functional analysis of the results to help in the annotation process. orthoFind is easy to use and has been proven to provide accurate results with different datasets. Availability: http://www.bioinfocabd.upo.es/orthofind/.
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12
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Boesler C, Rigo N, Agafonov DE, Kastner B, Urlaub H, Will CL, Lührmann R. Stable tri-snRNP integration is accompanied by a major structural rearrangement of the spliceosome that is dependent on Prp8 interaction with the 5' splice site. RNA (NEW YORK, N.Y.) 2015; 21:1993-2005. [PMID: 26385511 PMCID: PMC4604437 DOI: 10.1261/rna.053991.115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 08/21/2015] [Indexed: 05/22/2023]
Abstract
Exon definition is the predominant initial spliceosome assembly pathway in higher eukaryotes, but it remains much less well-characterized compared to the intron-defined assembly pathway. Addition in trans of an excess of 5'ss containing RNA to a splicing reaction converts a 37S exon-defined complex, formed on a single exon RNA substrate, into a 45S B-like spliceosomal complex with stably integrated U4/U6.U5 tri-snRNP. This 45S complex is compositonally and structurally highly similar to an intron-defined spliceosomal B complex. Stable tri-snRNP integration during B-like complex formation is accompanied by a major structural change as visualized by electron microscopy. The changes in structure and stability during transition from a 37S to 45S complex can be induced in affinity-purified cross-exon complexes by adding solely the 5'ss RNA oligonucleotide. This conformational change does not require the B-specific proteins, which are recruited during this stabilization process, or site-specific phosphorylation of hPrp31. Instead it is triggered by the interaction of U4/U6.U5 tri-snRNP components with the 5'ss sequence, most importantly between Prp8 and nucleotides at the exon-intron junction. These studies provide novel insights into the conversion of a cross-exon to cross-intron organized spliceosome and also shed light on the requirements for stable tri-snRNP integration during B complex formation.
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Affiliation(s)
- Carsten Boesler
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Norbert Rigo
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Dmitry E Agafonov
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Berthold Kastner
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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13
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Gayatri S, Bedford MT. Readers of histone methylarginine marks. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1839:702-10. [PMID: 24583552 PMCID: PMC4099268 DOI: 10.1016/j.bbagrm.2014.02.015] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 01/31/2014] [Accepted: 02/14/2014] [Indexed: 11/15/2022]
Abstract
Arginine methylation is a common posttranslational modification (PTM) that alters roughly 0.5% of all arginine residues in the cells. There are three types of arginine methylation: monomethylarginine (MMA), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA). These three PTMs are enriched on RNA-binding proteins and on histones, and also impact signal transduction cascades. To date, over thirty arginine methylation sites have been cataloged on the different core histones. These modifications alter protein structure, impact interactions with DNA, and also generate docking sites for effector molecules. The primary "readers" of methylarginine marks are Tudor domain-containing proteins. The complete family of thirty-six Tudor domain-containing proteins has yet to be fully characterized, but at least ten bind methyllysine motifs and eight bind methylarginine motifs. In this review, we will highlight the biological roles of the Tudor domains that interact with arginine methylated motifs, and also address other types of interactions that are regulated by these particular PTMs. This article is part of a Special Issue entitled: Molecular mechanisms of histone modification function.
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Affiliation(s)
- Sitaram Gayatri
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - Mark T Bedford
- Department of Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
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14
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Molecular evolution of the moonlighting protein SMN in metazoans. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2013; 8:220-30. [PMID: 23831553 DOI: 10.1016/j.cbd.2013.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 06/06/2013] [Accepted: 06/08/2013] [Indexed: 11/20/2022]
Abstract
The spinal muscular atrophy (SMA) associated protein survival of motor neuron (SMN) is known to be a moonlighting protein: having one primary, ancestral function (presumed to be involvement in U snRNP assembly) along with one or more secondary functions. One hypothesis for the evolution of moonlighting proteins is that regions of a structure under relatively weak negative selection could gain new functions without interfering with the primary function. To test this hypothesis, we investigated sequence conservation and dN/dS, which reflects the selection acting on a coding sequence, in SMN and a related protein, splicing factor 30 (SPF30), which is not currently known to be multifunctional. We found very different patterns of evolution in the two genes, with SPF30 characterized by strong sequence conservation and negative selection in most animal taxa investigated, and SMN with much lower sequence conservation, and much weaker negative selection at many sites. Evidence was found of positive selection acting on some sites in primate genes for SMN. SMN was also found to have been duplicated in a number of species, and with patterns that indicate reduced negative selection following some of these duplications. There were also several animal species lacking an SMN gene.
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15
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Abstract
Tudor domain proteins function as molecular adaptors, binding methylated arginine or lysine residues on their substrates to promote physical interactions and the assembly of macromolecular complexes. Here, we discuss the emerging roles of Tudor domain proteins during development, most notably in the Piwi-interacting RNA pathway, but also in other aspects of RNA metabolism, the DNA damage response and chromatin modification.
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Affiliation(s)
- Jun Wei Pek
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
| | - Amit Anand
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
| | - Toshie Kai
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117604
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16
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Hegele A, Kamburov A, Grossmann A, Sourlis C, Wowro S, Weimann M, Will CL, Pena V, Lührmann R, Stelzl U. Dynamic protein-protein interaction wiring of the human spliceosome. Mol Cell 2012; 45:567-80. [PMID: 22365833 DOI: 10.1016/j.molcel.2011.12.034] [Citation(s) in RCA: 285] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/01/2011] [Accepted: 12/12/2011] [Indexed: 12/12/2022]
Abstract
More than 200 proteins copurify with spliceosomes, the compositionally dynamic RNPs catalyzing pre-mRNA splicing. To better understand protein - protein interactions governing splicing, we systematically investigated interactions between human spliceosomal proteins. A comprehensive Y2H interaction matrix screen generated a protein interaction map comprising 632 interactions between 196 proteins. Among these, 242 interactions were found between spliceosomal core proteins and largely validated by coimmunoprecipitation. To reveal dynamic changes in protein interactions, we integrated spliceosomal complex purification information with our interaction data and performed link clustering. These data, together with interaction competition experiments, suggest that during step 1 of splicing, hPRP8 interactions with SF3b proteins are replaced by hSLU7, positioning this second step factor close to the active site, and that the DEAH-box helicases hPRP2 and hPRP16 cooperate through ordered interactions with GPKOW. Our data provide extensive information about the spliceosomal protein interaction network and its dynamics.
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Affiliation(s)
- Anna Hegele
- Otto-Warburg Laboratory, Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
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17
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Tripsianes K, Madl T, Machyna M, Fessas D, Englbrecht C, Fischer U, Neugebauer KM, Sattler M. Structural basis for dimethylarginine recognition by the Tudor domains of human SMN and SPF30 proteins. Nat Struct Mol Biol 2011; 18:1414-20. [PMID: 22101937 DOI: 10.1038/nsmb.2185] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 10/14/2011] [Indexed: 11/09/2022]
Abstract
Arginine dimethylation plays critical roles in the assembly of ribonucleoprotein complexes in pre-mRNA splicing and piRNA pathways. We report solution structures of SMN and SPF30 Tudor domains bound to symmetric and asymmetric dimethylated arginine (DMA) that is inherent in the RNP complexes. An aromatic cage in the Tudor domain mediates dimethylarginine recognition by electrostatic stabilization through cation-π interactions. Distinct from extended Tudor domains, dimethylarginine binding by the SMN and SPF30 Tudor domains is independent of proximal residues in the ligand. Yet, enhanced micromolar affinities are obtained by external cooperativity when multiple methylation marks are presented in arginine- and glycine-rich peptide ligands. A hydrogen bond network in the SMN Tudor domain, including Glu134 and a tyrosine hydroxyl of the aromatic cage, enhances cation-π interactions and is impaired by a mutation causing an E134K substitution associated with spinal muscular atrophy. Our structural analysis enables the design of an optimized binding pocket and the prediction of DMA binding properties of Tudor domains.
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18
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Mier P, Pérez-Pulido AJ. Fungal Smn and Spf30 homologues are mainly present in filamentous fungi and genomes with many introns: implications for spinal muscular atrophy. Gene 2011; 491:135-41. [PMID: 22020225 DOI: 10.1016/j.gene.2011.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/24/2011] [Accepted: 10/02/2011] [Indexed: 10/16/2022]
Abstract
Spinal muscular atrophy is an important rare genetic disease characterized by the loss of motor neurons, where the main gene responsible is smn1. Orthologous genes have only been characterized in a single fungal genome: Schizosaccharomyces pombe. We have searched for putative SMN orthologues in publically available fungal genomes, finding that they are predominately present in filamentous fungi. SMN binding partners and the SPF30 SMN paralogue, which are all involved in mRNA splicing, were found to be present in a similar but non-identical subset of fungal genomes. The Saccharomycces cerevisiae yeast genome contains neither smn1 orthologues nor paralogues and it has been suggested that this might be related to the low number of introns in this yeast. Here we have tested this hypothesis by looking at other fungal genomes. Significantly, we find that fungal genomes with high numbers of introns also possess an SMN orthologue or at least its paralogue, SPF30.
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Affiliation(s)
- Pablo Mier
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO, Facultad de Ciencias Experimentales (Área de Genética), Universidad Pablo de Olavide, 41013 Sevilla, Spain
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19
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Chen C, Nott TJ, Jin J, Pawson T. Deciphering arginine methylation: Tudor tells the tale. Nat Rev Mol Cell Biol 2011; 12:629-42. [PMID: 21915143 DOI: 10.1038/nrm3185] [Citation(s) in RCA: 221] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins can be modified by post-translational modifications such as phosphorylation, methylation, acetylation and ubiquitylation, creating binding sites for specific protein domains. Methylation has pivotal roles in the formation of complexes that are involved in cellular regulation, including in the generation of small RNAs. Arginine methylation was discovered half a century ago, but the ability of methylarginine sites to serve as binding motifs for members of the Tudor protein family, and the functional significance of the protein-protein interactions that are mediated by Tudor domains, has only recently been appreciated. Tudor proteins are now known to be present in PIWI complexes, where they are thought to interact with methylated PIWI proteins and regulate the PIWI-interacting RNA (piRNA) pathway in the germ line.
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Affiliation(s)
- Chen Chen
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
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20
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Schneider M, Hsiao HH, Will CL, Giet R, Urlaub H, Lührmann R. Human PRP4 kinase is required for stable tri-snRNP association during spliceosomal B complex formation. Nat Struct Mol Biol 2010; 17:216-21. [PMID: 20118938 DOI: 10.1038/nsmb.1718] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 10/09/2009] [Indexed: 11/09/2022]
Abstract
Reversible protein phosphorylation has an essential role during pre-mRNA splicing. Here we identify two previously unidentified phosphoproteins in the human spliceosomal B complex, namely the pre-mRNA processing factors PRP6 and PRP31, both components of the U4/U6-U5 tri-small nuclear ribonucleoprotein (snRNP). We provide evidence that PRP6 and PRP31 are directly phosphorylated by human PRP4 kinase (PRP4K) concomitant with their incorporation into B complexes. Immunodepletion and complementation studies with HeLa splicing extracts revealed that active human PRP4K is required for the phosphorylation of PRP6 and PRP31 and for the assembly of stable, functional B complexes. Thus, the phosphorylation of PRP6 and PRP31 is likely to have a key role during spliceosome assembly. Our data provide new insights into the molecular mechanism by which PRP4K contributes to splicing. They further indicate that numerous phosphorylation events contribute to spliceosome assembly and, thus, that splicing can potentially be modulated at multiple regulatory checkpoints.
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Affiliation(s)
- Marc Schneider
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
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21
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Splicing factor Spf30 assists exosome-mediated gene silencing in fission yeast. Mol Cell Biol 2009; 30:1145-57. [PMID: 20028739 DOI: 10.1128/mcb.01317-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Heterochromatin assembly in fission yeast relies on the processing of cognate noncoding RNAs by both the RNA interference and the exosome degradation pathways. Recent evidence indicates that splicing factors facilitate the cotranscriptional processing of centromeric transcripts into small interfering RNAs (siRNAs). In contrast, how the exosome contributes to heterochromatin assembly and whether it also relies upon splicing factors were unknown. We provide here evidence that fission yeast Spf30 is a splicing factor involved in the exosome pathway of heterochromatin silencing. Spf30 and Dis3, the main exosome RNase, colocalize at centromeric heterochromatin and euchromatic genes. At the centromeres, Dis3 helps recruiting Spf30, whose deficiency phenocopies the dis3-54 mutant: heterochromatin is impaired, as evidenced by reduced silencing and the accumulation of polyadenylated centromeric transcripts, but the production of siRNAs appears to be unaffected. Consistent with a direct role, Spf30 binds centromeric transcripts and locates at the centromeres in an RNA-dependent manner. We propose that Spf30, bound to nascent centromeric transcripts, perhaps with other splicing factors, assists their processing by the exosome. Splicing factor intercession may thus be a common feature of gene silencing pathways.
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22
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Lohrberg D, Krause E, Schümann M, Piontek J, Winkler L, Blasig IE, Haseloff RF. A strategy for enrichment of claudins based on their affinity to Clostridium perfringens enterotoxin. BMC Mol Biol 2009; 10:61. [PMID: 19545418 PMCID: PMC2713237 DOI: 10.1186/1471-2199-10-61] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 06/22/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Claudins, a family of protein localized in tight junctions, are essential for the control of paracellular permeation in epithelia and endothelia. The interaction of several claudins with Clostridium perfringens enterotoxin (CPE) has been exploited for an affinity-based enrichment of CPE-binding claudins from lysates of normal rat cholangiocytes. RESULTS Immunoblotting and mass spectrometry (MS) experiments demonstrate strong enrichment of the CPE-binding claudins -3, -4 and -7, indicating specific association with glutathione-S-transferase (GST)-CPE(116-319) fusion protein. In parallel, the co-elution of (non-CPE-binding) claudin-1 and claudin-5 was observed. The complete set of co-enriched proteins was identified by MS after electrophoretic separation. Relative mass spectrometric protein quantification with stable isotope labeling with amino acids in cell culture (SILAC) made it possible to discriminate specific binding from non-specific association to GST and/or matrix material. CONCLUSION CPE(116-319) provides an efficient tool for single step enrichment of different claudins from cell lysates. Numerous proteins were shown to be co-enriched with the CPE-binding claudins, but there are no indications (except for claudins -1 and -5) for an association with tight junctions.
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Affiliation(s)
- Dörte Lohrberg
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany.
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23
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Morris GE. The Cajal body. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:2108-15. [PMID: 18755223 DOI: 10.1016/j.bbamcr.2008.07.016] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 07/21/2008] [Accepted: 07/23/2008] [Indexed: 12/30/2022]
Abstract
The Cajal body, originally identified over 100 years ago as a nucleolar accessory body in neurons, has come to be identified with nucleoplasmic structures, often quite tiny, that contain coiled threads of the marker protein, coilin. The interaction of coilin with other proteins appears to increase the efficiency of several nuclear processes by concentrating their components in the Cajal body. The best-known of these processes is the modification and assembly of U snRNPs, some of which eventually form the RNA splicing machinery, or spliceosome. Over the last 10 years, research into the function of Cajal bodies has been greatly stimulated by the discovery that SMN, the protein deficient in the inherited neuromuscular disease, spinal muscular atrophy, is a Cajal body component and has an essential role in the assembly of spliceosomal U snRNPs in the cytoplasm and their delivery to the Cajal body in the nucleus.
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Affiliation(s)
- Glenn E Morris
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, OSWESTRY, SY10 7AG, UK.
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24
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Goulet I, Boisvenue S, Mokas S, Mazroui R, Côté J. TDRD3, a novel Tudor domain-containing protein, localizes to cytoplasmic stress granules. Hum Mol Genet 2008; 17:3055-74. [PMID: 18632687 PMCID: PMC2536506 DOI: 10.1093/hmg/ddn203] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our previous work has demonstrated that the Tudor domain of the ‘survival of motor neuron’ protein and the Tudor domain-containing protein 3 (TDRD3) are highly similar and that they both have the ability to interact with arginine-methylated polypeptides. TDRD3 has been identified among genes whose overexpression has a strong predictive value for poor prognosis of estrogen receptor-negative breast cancers, although its precise function remains unknown. TDRD3 is a modular protein, and in addition to its Tudor domain, it harbors a putative nucleic acid recognition motif and a ubiquitin-associated domain. We report here that TDRD3 localizes predominantly to the cytoplasm, where it co-sediments with the fragile X mental retardation protein on actively translating polyribosomes. We also demonstrate that TDRD3 accumulates into stress granules (SGs) in response to various cellular stresses. Strikingly, the Tudor domain of TDRD3 was found to be both required and sufficient for its recruitment to SGs, and the methyl-binding surface in the Tudor domain is important for this process. Pull down experiments identified five novel TDRD3 interacting partners, most of which are potentially methylated RNA-binding proteins. Our findings revealed that two of these proteins, SERPINE1 mRNA-binding protein 1 and DEAD/H box-3 (a gene often deleted in Sertoli-cell-only syndrome), are also novel constituents of cytoplasmic SGs. Taken together, we report the first characterization of TDRD3 and its functional interaction with at least two proteins implicated in human genetic diseases and present evidence supporting a role for arginine methylation in the regulation of SG dynamics.
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Affiliation(s)
- Isabelle Goulet
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5
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Little JT, Jurica MS. Splicing Factor SPF30 Bridges an Interaction between the Prespliceosome Protein U2AF35 and Tri-small Nuclear Ribonucleoprotein Protein hPrp3. J Biol Chem 2008; 283:8145-52. [DOI: 10.1074/jbc.m707984200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Yang J, Välineva T, Hong J, Bu T, Yao Z, Jensen ON, Frilander MJ, Silvennoinen O. Transcriptional co-activator protein p100 interacts with snRNP proteins and facilitates the assembly of the spliceosome. Nucleic Acids Res 2007; 35:4485-94. [PMID: 17576664 PMCID: PMC1935017 DOI: 10.1093/nar/gkm470] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcription and pre-mRNA splicing are the key nuclear processes in eukaryotic gene expression, and identification of factors common to both processes has suggested that they are functionally coordinated. p100 protein has been shown to function as a transcriptional co-activator for several transcription factors. p100 consists of staphylococcal nuclease (SN)-like and Tudor-SN (TSN) domains of which the SN-like domains have been shown to function in transcription, but the function of TSN domain has remained elusive. Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing. The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs. In vitro splicing assays revealed that the purified p100, and specifically the TSN domain of p100, accelerates the kinetics of the spliceosome assembly, particularly the formation of complex A, and the transition from complex A to B. Consistently, the p100 protein, as well as the separated TSN domain, enhanced the kinetics of the first step of splicing in an in vitro splicing assay in dose-dependent manner. Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.
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Affiliation(s)
- Jie Yang
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Tuuli Välineva
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Jingxin Hong
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Tianxu Bu
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Zhi Yao
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Ole N. Jensen
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Mikko J. Frilander
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Olli Silvennoinen
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
- *To whom correspondence should be addressed. Tel:+358 3 3551 7845; Fax:+358 3 3551 7332; Correspondence may also be addressed to Jie Yang. Tel:+86 22 23542520 +86 22 23542581
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Bratanich A, Blanchetot A. A Gene Similar to the Human Hyaluronan-mediated Motility Receptor (RHAMM) Gene is Upregulated During Porcine Circovirus Type 2 Infection. Virus Genes 2006; 32:145-52. [PMID: 16604446 DOI: 10.1007/s11262-005-6870-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/07/2005] [Accepted: 07/25/2005] [Indexed: 11/29/2022]
Abstract
Little is known on the cellular events triggered by the Porcine Circovirus type 2 (PCV2) in Porcine Multisystemic Wasting Syndrome (PMWS). The differential display reverse-transcription PCR (DDRT-PCR) was used to identify cellular target molecules in lymph node tissue that were regulated in PMWS. Comparative profile analysis of a pool of lymph node tissues from PMWS and healthy animals showed that some transcripts were up-regulated in PMWS. Bacterial recombinant clones containing up-regulated transcripts were analyzed by reverse dot blot. Clones showing enhanced hybridization when probed with cDNAs from PMWS animals were sequenced and compared to existing databases. Two of the differentially regulated transcripts displayed homology with human genes such as an RNA splicing factor and hyaluronan-mediated motility receptor (RHAMM). Clones encoding theses genes were subsequently used as probes to analyze their expression pattern in PK15 cells persistently infected with PCV2. Northern blot analyzes indicated that these transcripts were up-regulated in these cells as observed in infected lymph node tissue from PMWS cases. A role for the up-regulation of the RHAMM gene is proposed.
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Affiliation(s)
- Ana Bratanich
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, 58105, USA.
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Gonzalez-Santos JM, Cao H, Wang A, Koehler DR, Martin B, Navab R, Hu J. A complementation method for functional analysis of mammalian genes. Nucleic Acids Res 2005; 33:e94. [PMID: 15944448 PMCID: PMC1145195 DOI: 10.1093/nar/gni093] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our progress in understanding mammalian gene function has lagged behind that of gene identification. New methods for mammalian gene functional analysis are needed to accelerate the process. In yeast, the powerful genetic shuffle system allows deletion of any chromosomal gene by homologous recombination and episomal expression of a mutant allele in the same cell. Here, we report a method for mammalian cells, which employs a helper-dependent adenoviral (HD-Ad) vector to synthesize small hairpin (sh) RNAs to knock-down the expression of an endogenous gene by targeting untranslated regions (UTRs). The vector simultaneously expresses an exogenous version of the same gene (wild-type or mutant allele) lacking the UTRs for functional analysis. We demonstrated the utility of the method by using PRPF3, which encodes the human RNA splicing factor Hprp3p. Recently, missense mutations in PRPF3 were found to cause autosomal-dominant Retinitis Pigmentosa, a form of genetic eye diseases affecting the retina. We knocked-down endogenous PRPF3 in multiple cell lines and rescued the phenotype (cell death) with exogenous PRPF3 cDNA, thereby creating a genetic complementation method. Because Ad vectors can efficiently transduce a wide variety of cell types, and many tissues in vivo, this method could have a wide application for gene function studies.
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Affiliation(s)
- Juana Maria Gonzalez-Santos
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
- Laboratory Medicine and Pathobiology, University of TorontoToronto, Canada M5S 1A1
| | - Huibi Cao
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
- Laboratory Medicine and Pathobiology, University of TorontoToronto, Canada M5S 1A1
| | - Anan Wang
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
| | - David R. Koehler
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
- Laboratory Medicine and Pathobiology, University of TorontoToronto, Canada M5S 1A1
| | - Bernard Martin
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
| | - Roya Navab
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
- Laboratory Medicine and Pathobiology, University of TorontoToronto, Canada M5S 1A1
| | - Jim Hu
- Programme in Lung Biology Research and the Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick ChildrenToronto, Canada M5G 1X8 and
- Department of Paediatrics, University of TorontoToronto, Canada M5S 1A1
- Laboratory Medicine and Pathobiology, University of TorontoToronto, Canada M5S 1A1
- To whom correspondence should be addressed. Tel: +1 416 813 6412; Fax: +1 416 813 5771;
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Abstract
The Tudor domain is an approximately 60-amino acid structure motif in search of a function. Herein we show that the Tudor domains of the spinal muscular atrophy gene product SMN, the splicing factor 30 kDa (SPF30), and the Tudor domain-containing 3 (TDRD3) proteins interacted with arginine-glycine-rich motifs in a methylarginine-dependent manner. The Tudor domains also associated with methylarginine-containing cellular proteins, providing evidence that methylated arginines represent physiological ligands for this protein module. In addition, we report that spliceosomal small nuclear ribonucleoprotein particles core Sm proteins accumulated in the cytoplasm when arginine methylation was inhibited with adenosine dialdehyde or in the presence of an excessive amount of unmethylated arginine-glycine-rich peptides. These data provide in vivo evidence in support of a role for arginine methylation in the proper assembly and localization of spliceosomal Sm proteins.
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Affiliation(s)
- Jocelyn Côté
- Terry Fox Molecular Oncology Group and the Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital and Department of Oncology, McGill University, Montréal, Québec H3T 1E2, Canada
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Makarova OV, Makarov EM, Urlaub H, Will CL, Gentzel M, Wilm M, Lührmann R. A subset of human 35S U5 proteins, including Prp19, function prior to catalytic step 1 of splicing. EMBO J 2004; 23:2381-91. [PMID: 15175653 PMCID: PMC423283 DOI: 10.1038/sj.emboj.7600241] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Accepted: 04/27/2004] [Indexed: 11/09/2022] Open
Abstract
During catalytic activation of the spliceosome, snRNP remodeling events occur, leading to the formation of a 35S U5 snRNP that contains a large group of proteins, including Prp19 and CDC5, not found in 20S U5 snRNPs. To investigate the function of 35S U5 proteins, we immunoaffinity purified human spliceosomes that had not yet undergone catalytic activation (designated BDeltaU1), which contained U2, U4, U5, and U6, but lacked U1 snRNA. Comparison of the protein compositions of BDeltaU1 and activated B* spliceosomes revealed that, whereas U4/U6 snRNP proteins are stably associated with BDeltaU1 spliceosomes, 35S U5-associated proteins (which are present in B*) are largely absent, suggesting that they are dispensable for complex B formation. Indeed, immunodepletion/complementation experiments demonstrated that a subset of 35S U5 proteins including Prp19, which form a stable heteromeric complex, are required prior to catalytic step 1 of splicing, but not for stable integration of U4/U6.U5 tri-snRNPs. Thus, comparison of the proteomes of spliceosomal complexes at defined stages can provide information as to which proteins function as a group at a particular step of splicing.
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Affiliation(s)
- Olga V Makarova
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Evgeny M Makarov
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Henning Urlaub
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marc Gentzel
- EMBL, Bioanalytical Research Group, Heidelberg, Germany
| | - Matthias Wilm
- EMBL, Bioanalytical Research Group, Heidelberg, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany. Tel.: +49 551 201 1407; Fax: +49 551 201 1197; E-mail:
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31
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Bauer A, Kuster B. Affinity purification-mass spectrometry. Powerful tools for the characterization of protein complexes. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:570-8. [PMID: 12581197 DOI: 10.1046/j.1432-1033.2003.03428.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Multi-protein complexes are emerging as important entities of biological activity inside cells that serve to create functional diversity by contextual combination of gene products and, at the same time, organize the large number of different proteins into functional units. Many a time, when studying protein complexes rather than individual proteins, the biological insight gained has been fundamental, particularly in cases in which proteins with no previous functional annotation could be placed into a functional context derived from their 'molecular environment'. In this minireview, we summarize the current state of the art for the retrieval of multiprotein complexes by affinity purification and their analysis by mass spectrometry. The advances in technology made over the past few years now enable the study of protein complexes on a proteomic scale and it can be anticipated that the knowledge gathered from such projects will fuel drug target discovery and validation pipelines and that the technology is also going to prove valuable in the emerging field of systems biology.
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32
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Ajuh P, Chusainow J, Ryder U, Lamond AI. A novel function for human factor C1 (HCF-1), a host protein required for herpes simplex virus infection, in pre-mRNA splicing. EMBO J 2002; 21:6590-602. [PMID: 12456665 PMCID: PMC136956 DOI: 10.1093/emboj/cdf652] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human factor C1 (HCF-1) is needed for the expression of herpes simplex virus 1 (HSV-1) immediate-early genes in infected mammalian cells. Here, we provide evidence that HCF-1 is required for spliceosome assembly and splicing in mammalian nuclear extracts. HCF-1 interacts with complexes containing splicing snRNPs in uninfected mammalian cells and is a stable component of the spliceosome complex. We show that a missense mutation in HCF-1 in the BHK21 hamster cell line tsBN67, at the non-permissive temperature, inhibits the protein's interaction with U1 and U5 splicing snRNPs, causes inefficient spliceosome assembly and inhibits splicing. Transient expression of wild-type HCF-1 in tsBN67 cells restores splicing at the non-permissive temperature. The inhibition of splicing in tsBN67 cells correlates with the temperature-sensitive cell cycle arrest phenotype, suggesting that HCF-1-dependent splicing events may be required for cell cycle progression.
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Affiliation(s)
| | | | | | - Angus I. Lamond
- School of Life Sciences, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
Corresponding author e-mail:
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Will CL, Urlaub H, Achsel T, Gentzel M, Wilm M, Lührmann R. Characterization of novel SF3b and 17S U2 snRNP proteins, including a human Prp5p homologue and an SF3b DEAD-box protein. EMBO J 2002; 21:4978-88. [PMID: 12234937 PMCID: PMC126279 DOI: 10.1093/emboj/cdf480] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mass spectrometry was used to identify novel proteins associated with the human 17S U2 snRNP and one of its stable subunits, SF3b. Several additional proteins were identified, demonstrating that 17S U2 snRNPs are significantly more complex than previously thought. Two of the newly identified proteins, namely the DEAD-box proteins SF3b125 and hPrp5 (a homologue of Saccharomyces cerevisiae Prp5p) were characterized further. Immunodepletion experiments with HeLa nuclear extract indicated that hPrp5p plays an important role in pre-mRNA splicing, acting during or prior to prespliceosome assembly. The SF3b-associated protein SF3b125 dissociates at the time of 17S U2 formation, raising the interesting possibility that it might facilitate the assembly of the 17S U2 snRNP. Finally, immunofluorescence/FISH studies revealed a differential subnuclear distribution of U2 snRNA, hPrp5p and SF3b125, which were enriched in Cajal bodies, versus SF3b155 and SF3a120, which were not; a model for 17S U2 snRNP assembly based on these findings is presented. Taken together, these studies provide new insight into the composition of the 17S U2 snRNP and the potential function of several of its proteins.
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Affiliation(s)
| | | | | | - Marc Gentzel
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Göttingen and
EMBL, Bioanalytical Research Group, D-69117 Heidelberg, Germany Corresponding author e-mail:
| | - Matthias Wilm
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Göttingen and
EMBL, Bioanalytical Research Group, D-69117 Heidelberg, Germany Corresponding author e-mail:
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Göttingen and
EMBL, Bioanalytical Research Group, D-69117 Heidelberg, Germany Corresponding author e-mail:
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Rappsilber J, Ryder U, Lamond AI, Mann M. Large-scale proteomic analysis of the human spliceosome. Genome Res 2002; 12:1231-45. [PMID: 12176931 PMCID: PMC186633 DOI: 10.1101/gr.473902] [Citation(s) in RCA: 695] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In a previous proteomic study of the human spliceosome, we identified 42 spliceosome-associated factors, including 19 novel ones. Using enhanced mass spectrometric tools and improved databases, we now report identification of 311 proteins that copurify with splicing complexes assembled on two separate pre-mRNAs. All known essential human splicing factors were found, and 96 novel proteins were identified, of which 55 contain domains directly linking them to functions in splicing/RNA processing. We also detected 20 proteins related to transcription, which indicates a direct connection between this process and splicing. This investigation provides the most detailed inventory of human spliceosome-associated factors to date, and the data indicate a number of interesting links coordinating splicing with other steps in the gene expression pathway.
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Affiliation(s)
- Juri Rappsilber
- Protein Interaction Laboratory in the Center of Experimental Bioinformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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Gonzalez-Santos JM, Wang A, Jones J, Ushida C, Liu J, Hu J. Central region of the human splicing factor Hprp3p interacts with Hprp4p. J Biol Chem 2002; 277:23764-72. [PMID: 11971898 DOI: 10.1074/jbc.m111461200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human splicing factors Hprp3p and Hprp4p are associated with the U4/U6 small nuclear ribonucleoprotein particle, which is essential for the assembly of an active spliceosome. Currently, little is known about the specific roles of these factors in splicing. In this study, we characterized the molecular interaction between Hprp3p and Hprp4p. Constructs were created for expression of Hprp3p or its mutants in bacterial or mammalian cells. We showed that antibodies against either Hprp3p or Hprp4p were able to pull-down the Hprp3p-Hprp4p complex formed in Escherichia coli lysates. By co-immunoprecipitation and isothermal titration calorimetry, we demonstrated that purified Hprp3p and its mutants containing the central region, but lacking either the N-terminal 194 amino acids or the C-terminal 240 amino acids, were able to interact with Hprp4p. Conversely, Hprp3p mutants containing only the N- or C-terminal region did not interact with Hprp4p. In addition, by co-immunoprecipitation, we showed that intact Hprp3p and its mutants containing the central region interacted with Hprp4p in HeLa cell nuclear extracts. Primer extension analysis illustrated that the central region of Hprp3p is required to maintain the association of Hprp3p-Hprp4p with U4/U6 small nuclear RNAs, suggesting that this Hprp3p/Hprp4p interaction allows the recruitment of Hprp4p, and perhaps other protein(s), to the U4/U6 small nuclear ribonucleoprotein particle.
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Schneider C, Will CL, Makarova OV, Makarov EM, Lührmann R. Human U4/U6.U5 and U4atac/U6atac.U5 tri-snRNPs exhibit similar protein compositions. Mol Cell Biol 2002; 22:3219-29. [PMID: 11971955 PMCID: PMC133795 DOI: 10.1128/mcb.22.10.3219-3229.2002] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the U12-dependent spliceosome, the U4atac/U6atac snRNP represents the functional analogue of the major U4/U6 snRNP. Little information is available presently regarding the protein composition of the former snRNP and its association with other snRNPs. In this report we show that human U4atac/U6atac di-snRNPs associate with U5 snRNPs to form a 25S U4atac/U6atac.U5 trimeric particle. Comparative analysis of minor and major tri-snRNPs by using immunoprecipitation experiments revealed that their protein compositions are very similar, if not identical. Not only U5-specific proteins but, surprisingly, all tested U4/U6- and major tri-snRNP-specific proteins were detected in the minor tri-snRNP complex. Significantly, the major tri-snRNP-specific proteins 65K and 110K, which are required for integration of the major tri-snRNP into the U2-dependent spliceosome, were among those proteins detected in the minor tri-snRNP, raising an interesting question as to how the specificity of addition of tri-snRNP to the corresponding spliceosome is maintained. Moreover, immunodepletion studies demonstrated that the U4/U6-specific 61K protein, which is involved in the formation of major tri-snRNPs, is essential for the association of the U4atac/U6atac di-snRNP with U5 to form the U4atac/U6atac.U5 tri-snRNP. Subsequent immunoprecipitation studies demonstrated that those proteins detected in the minor tri-snRNP complex are also incorporated into U12-dependent spliceosomes. This remarkable conservation of polypeptides between minor and major spliceosomes, coupled with the absence of significant sequence similarity between the functionally analogous snRNAs, supports an evolutionary model in which most major and minor spliceosomal proteins, but not snRNAs, are derived from a common ancestor.
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Affiliation(s)
- Claudia Schneider
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, D-37077 Göttingen, Germany
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37
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Abstract
The annotation of the human genome indicates the surprisingly low number of approximately 40,000 genes. However, the estimated number of proteins encoded by these genes is two to three orders of magnitude higher. The ability to unambiguously identify the proteins is a prerequisite for their functional investigation. As proteins derived from the same gene can be largely identical, and might differ only in small but functionally relevant details, protein identification tools must not only identify a large number of proteins but also be able to differentiate between close relatives. This information can be generated by mass spectrometry, an approach that identifies proteins by partial analysis of their digestion-derived peptides. Information gleaned from databases fills in the missing sequence information. Because both sequence databases and experimental data are limited, a certain ambiguity often remains concerning which sequence variant(s) and modification(s) are present. As the common denominator of all the isoforms is a gene, in our opinion, it would be more accurate to state that a product of this particular gene rather than a certain protein has been identified by mass spectrometry.
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Affiliation(s)
- Juri Rappsilber
- Protein Interaction Laboratory, Center of Experimental Bioinformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 M Odense, Denmark.
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