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Ripin N, Parker R. Formation, function, and pathology of RNP granules. Cell 2023; 186:4737-4756. [PMID: 37890457 PMCID: PMC10617657 DOI: 10.1016/j.cell.2023.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/28/2023] [Accepted: 09/07/2023] [Indexed: 10/29/2023]
Abstract
Ribonucleoprotein (RNP) granules are diverse membrane-less organelles that form through multivalent RNA-RNA, RNA-protein, and protein-protein interactions between RNPs. RNP granules are implicated in many aspects of RNA physiology, but in most cases their functions are poorly understood. RNP granules can be described through four key principles. First, RNP granules often arise because of the large size, high localized concentrations, and multivalent interactions of RNPs. Second, cells regulate RNP granule formation by multiple mechanisms including posttranslational modifications, protein chaperones, and RNA chaperones. Third, RNP granules impact cell physiology in multiple manners. Finally, dysregulation of RNP granules contributes to human diseases. Outstanding issues in the field remain, including determining the scale and molecular mechanisms of RNP granule function and how granule dysfunction contributes to human disease.
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Affiliation(s)
- Nina Ripin
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA.
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2
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Pánek J, Roithová A, Radivojević N, Sýkora M, Prusty AB, Huston N, Wan H, Pyle AM, Fischer U, Staněk D. The SMN complex drives structural changes in human snRNAs to enable snRNP assembly. Nat Commun 2023; 14:6580. [PMID: 37852981 PMCID: PMC10584915 DOI: 10.1038/s41467-023-42324-0] [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: 06/11/2021] [Accepted: 10/06/2023] [Indexed: 10/20/2023] Open
Abstract
Spliceosomal snRNPs are multicomponent particles that undergo a complex maturation pathway. Human Sm-class snRNAs are generated as 3'-end extended precursors, which are exported to the cytoplasm and assembled together with Sm proteins into core RNPs by the SMN complex. Here, we provide evidence that these pre-snRNA substrates contain compact, evolutionarily conserved secondary structures that overlap with the Sm binding site. These structural motifs in pre-snRNAs are predicted to interfere with Sm core assembly. We model structural rearrangements that lead to an open pre-snRNA conformation compatible with Sm protein interaction. The predicted rearrangement pathway is conserved in Metazoa and requires an external factor that initiates snRNA remodeling. We show that the essential helicase Gemin3, which is a component of the SMN complex, is crucial for snRNA structural rearrangements during snRNP maturation. The SMN complex thus facilitates ATP-driven structural changes in snRNAs that expose the Sm site and enable Sm protein binding.
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Affiliation(s)
- Josef Pánek
- Laboratory of Bioinformatics, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Adriana Roithová
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
- Laboratory of Regulation of Gene Expression, Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Nenad Radivojević
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Michal Sýkora
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | | | - Nicholas Huston
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, USA
| | - Han Wan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, USA
- Department of Chemistry, Yale University, New Haven, USA
- Howard Hughes Medical Institute, Chevy Chase, USA
| | - Utz Fischer
- Department of Biochemistry, Theodor Boveri Institute, University of Würzburg, Würzburg, Germany
| | - David Staněk
- Laboratory of RNA Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic.
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3
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Xiong F, Ren JJ, Wang YY, Zhou Z, Qi HD, Otegui MS, Wang XL. An Arabidopsis Retention and Splicing complex regulates root and embryo development through pre-mRNA splicing. PLANT PHYSIOLOGY 2022; 190:621-639. [PMID: 35640107 PMCID: PMC9434225 DOI: 10.1093/plphys/kiac256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/08/2022] [Indexed: 05/30/2023]
Abstract
Pre-mRNA splicing is an important step in the posttranscriptional processing of transcripts and a key regulator of development. The heterotrimeric retention and splicing (RES) complex plays vital roles in the growth and development of yeast, zebrafish, and humans by mediating pre-mRNA splicing of multiple genes. However, whether the RES complex is conserved in plants and what specific functions it has remain unknown. In this study, we identified Arabidopsis (Arabidopsis thaliana) BUD13 (AtBUD13), GROWTH, DEVELOPMENT AND SPLICING 1 (GDS1), and DAWDLE (DDL) as the counterparts of the yeast RES complex subunits Bud site selection protein 13 (Bud13), U2 snRNP component Snu17 (Snu17), and Pre-mRNA leakage protein 1, respectively. Moreover, we showed that RES is an ancient complex evolutionarily conserved in eukaryotes. GDS1 directly interacts with both AtBUD13 and DDL in nuclear speckles. The BUD13 domain of AtBUD13 and the RNA recognition motif domain of GDS1 are necessary and sufficient for AtBUD13-GDS1 interaction. Mutants of AtBUD13, GDS1, and DDL failed to properly splice multiple genes involved in cell proliferation and showed defects in early embryogenesis and root development. In addition, we found that GDS1 and DDL interact, respectively, with the U2 small nuclear ribonucleoproteins auxiliary factor AtU2AF65B and the NineTeen Complex-related splicing factor SKIP, which are essential for early steps of spliceosome assembly and recognition of splice sites. Altogether, our work reveals that the Arabidopsis RES complex is important for root and early embryo development by modulating pre-mRNA splicing.
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Affiliation(s)
- Feng Xiong
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Jing-Jing Ren
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Yu-Yi Wang
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Zhou Zhou
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Hao-Dong Qi
- National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian 271018, China
| | - Marisa S Otegui
- Department of Botany, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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4
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López-Cortés A, Echeverría-Garcés G, Ramos-Medina MJ. Molecular Pathogenesis and New Therapeutic Dimensions for Spinal Muscular Atrophy. BIOLOGY 2022; 11:biology11060894. [PMID: 35741415 PMCID: PMC9219894 DOI: 10.3390/biology11060894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 11/16/2022]
Abstract
The condition known as 5q spinal muscular atrophy (SMA) is a devastating autosomal recessive neuromuscular disease caused by a deficiency of the ubiquitous protein survival of motor neuron (SMN), which is encoded by the SMN1 and SMN2 genes. It is one of the most common pediatric recessive genetic diseases, and it represents the most common cause of hereditary infant mortality. After decades of intensive basic and clinical research efforts, and improvements in the standard of care, successful therapeutic milestones have been developed, delaying the progression of 5q SMA and increasing patient survival. At the same time, promising data from early-stage clinical trials have indicated that additional therapeutic options are likely to emerge in the near future. Here, we provide updated information on the molecular underpinnings of SMA; we also provide an overview of the rapidly evolving therapeutic landscape for SMA, including SMN-targeted therapies, SMN-independent therapies, and combinational therapies that are likely to be key for the development of treatments that are effective across a patient’s lifespan.
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Affiliation(s)
- Andrés López-Cortés
- Programa de Investigación en Salud Global, Facultad de Ciencias de la Salud, Universidad Internacional SEK, Quito 170302, Ecuador
- Facultad de Medicina, Universidad de Las Américas, Quito 170124, Ecuador
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
- Correspondence:
| | - Gabriela Echeverría-Garcés
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
| | - María José Ramos-Medina
- Latin American Network for the Implementation and Validation of Clinical Pharmacogenomics Guidelines (RELIVAF-CYTED), 28001 Madrid, Spain; (G.E.-G.); (M.J.R.-M.)
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5
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Cao H, Wang Y, Zhang N, Xia S, Tian P, Lu L, Du J, Du Y. Progress of CRISPR-Cas13 Mediated Live-Cell RNA Imaging and Detection of RNA-Protein Interactions. Front Cell Dev Biol 2022; 10:866820. [PMID: 35356276 PMCID: PMC8959342 DOI: 10.3389/fcell.2022.866820] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 02/21/2022] [Indexed: 12/26/2022] Open
Abstract
Ribonucleic acid (RNA) and proteins play critical roles in gene expression and regulation. The relevant study increases the understanding of various life processes and contributes to the diagnosis and treatment of different diseases. RNA imaging and mapping RNA-protein interactions expand the understanding of RNA biology. However, the existing methods have some limitations. Recently, precise RNA targeting of CRISPR-Cas13 in cells has been reported, which is considered a new promising platform for RNA imaging in living cells and recognition of RNA-protein interactions. In this review, we first described the current findings on Cas13. Furthermore, we introduced current tools of RNA real-time imaging and mapping RNA-protein interactions and highlighted the latest advances in Cas13-mediated tools. Finally, we discussed the advantages and disadvantages of Cas13-based methods, providing a set of new ideas for the optimization of Cas13-mediated methods.
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Affiliation(s)
- Huake Cao
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Yuechen Wang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Ning Zhang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Siyuan Xia
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- Second School of Clinical Medicine, Anhui Medical University, Hefei, China
| | - Pengfei Tian
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- First School of Clinical Medicine, Anhui Medical University, Hefei, China
- First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Li Lu
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Juan Du
- School of Medicine, The Chinese University of Hong Kong, Shenzhen, China
- Longgang District People’s Hospital of Shenzhen & The Second Affiliated Hospital, The Chinese University of Hong Kong, Shenzhen, China
- *Correspondence: Yinan Du, ; Juan Du,
| | - Yinan Du
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
- *Correspondence: Yinan Du, ; Juan Du,
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6
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Jutzi D, Ruepp MD. Alternative Splicing in Human Biology and Disease. Methods Mol Biol 2022; 2537:1-19. [PMID: 35895255 DOI: 10.1007/978-1-0716-2521-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Alternative pre-mRNA splicing allows for the production of multiple mRNAs from an individual gene, which not only expands the protein-coding potential of the genome but also enables complex mechanisms for the post-transcriptional control of gene expression. Regulation of alternative splicing entails a combinatorial interplay between an abundance of trans-acting splicing factors, cis-acting regulatory sequence elements and their concerted effects on the core splicing machinery. Given the extent and biological significance of alternative splicing in humans, it is not surprising that aberrant splicing patterns can cause or contribute to a wide range of diseases. In this introductory chapter, we outline the mechanisms that govern alternative pre-mRNA splicing and its regulation and discuss how dysregulated splicing contributes to human diseases affecting the motor system and the brain.
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Affiliation(s)
- Daniel Jutzi
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.
| | - Marc-David Ruepp
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.
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7
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Campagne S, de Vries T, Allain FHT. Probing the Interactions of Splicing Regulatory Small Molecules and Proteins with U1 snRNP Using NMR Spectroscopy. Methods Mol Biol 2022; 2537:247-262. [PMID: 35895269 DOI: 10.1007/978-1-0716-2521-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Alternative RNA splicing is an essential part of gene expression that not only increases the protein diversity of metazoan but also provides an additional layer of gene expression regulation. The U1 small ribonucleoparticle (U1 snRNP) plays an essential role in seeding spliceosome assembly and its binding on weak 5'-splice sites is regulated by transient interactions with splicing factors. Recent progress in allele specific splicing correction has shown the therapeutic potential offered by small molecule splicing modifiers that specifically promotes the recruitment of U1 snRNP to modulate alternative splicing and gene expression. Here, we described a method to reconstitute U1 snRNP in vitro and to study labile interactions with protein or synthetic splicing factors using solution state NMR spectroscopy. This approach allowed us to validate direct interactions between splicing regulators and U1 snRNP and could also be useful for the screening of small molecules acting on splicing regulation.
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Affiliation(s)
- Sébastien Campagne
- ARNA Laboratory, INSERM U1212, CNRS 5320, University of Bordeaux, Bordeaux, France.
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, Zurich, Switzerland.
| | - Tebbe de Vries
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Frédéric H-T Allain
- Department of Biology, Institute of Biochemistry, Swiss Federal Institute of Technology, Zurich, Switzerland.
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8
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Lin X, Fonseca MAS, Breunig JJ, Corona RI, Lawrenson K. In vivo discovery of RNA proximal proteins via proximity-dependent biotinylation. RNA Biol 2021; 18:2203-2217. [PMID: 34006179 PMCID: PMC8648264 DOI: 10.1080/15476286.2021.1917215] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/16/2021] [Accepted: 04/10/2021] [Indexed: 12/12/2022] Open
Abstract
RNA molecules function as messenger RNAs (mRNAs) that encode proteins and noncoding transcripts that serve as adaptor molecules, structural components, and regulators of genome organization and gene expression. Their function and regulation are largely mediated by RNA binding proteins (RBPs). Here we present RNA proximity labelling (RPL), an RNA-centric method comprising the endonuclease-deficient Type VI CRISPR-Cas protein dCas13b fused to engineered ascorbate peroxidase APEX2. RPL discovers target RNA proximal proteins in vivo via proximity-based biotinylation. RPL applied to U1 identified proteins involved in both U1 canonical and noncanonical functions. Profiling of poly(A) tail proximal proteins uncovered expected categories of RBPs and provided additional evidence for 5'-3' proximity and unexplored subcellular localizations of poly(A)+ RNA. Our results suggest that RPL allows rapid identification of target RNA binding proteins in native cellular contexts, and is expected to pave the way for discovery of novel RNA-protein interactions important for health and disease.
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Affiliation(s)
- Xianzhi Lin
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Marcos A. S. Fonseca
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Joshua J. Breunig
- Cedars-Sinai Medical Center, Board of Governors Regenerative Medicine Institute, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Cedars-Sinai Medical Center, Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Rosario I. Corona
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Kate Lawrenson
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Cedars-Sinai Medical Center, Center for Bioinformatics and Functional Genomics, Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
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9
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Alternative polyadenylation: An untapped source for prostate cancer biomarkers and therapeutic targets? Asian J Urol 2021; 8:407-415. [PMID: 34765448 PMCID: PMC8566364 DOI: 10.1016/j.ajur.2021.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/20/2021] [Accepted: 05/05/2021] [Indexed: 11/25/2022] Open
Abstract
Objective To review alternative polyadenylation (APA) as a mechanism of gene regulation and consider potential roles for APA in prostate cancer (PCa) biology and treatment. Methods An extensive review of mRNA polyadenylation, APA, and PCa literature was performed. This review article introduces APA and its association with human disease, outlines the mechanisms and components of APA, reviews APA in cancer biology, and considers whether APA may contribute to PCa progression and/or produce novel biomarkers and therapeutic targets for PCa. Results Eukaryotic mRNA 3′-end cleavage and polyadenylation play a critical role in gene expression. Most human genes encode more than one polyadenylation signal, and produce more than one transcript isoform, through APA. Polyadenylation can occur throughout the gene body to generate transcripts with differing 3′-termini and coding sequence. Differences in 3′-untranslated regions length can modify post-transcriptional gene regulation by microRNAs and RNA binding proteins, and alter mRNA stability, translation efficiency, and subcellular localization. Distinctive APA patterns are associated with human diseases, tissue origins, and changes in cellular proliferation rate and differentiation state. APA events may therefore generate unique mRNA biomarkers or therapeutic targets in certain cancer types or phenotypic states. Conclusions The full extent of cancer-associated and tissue-specific APA events have yet to be defined, and the mechanisms and functional consequences of APA in cancer remain incompletely understood. There is evidence that APA is active in PCa, and that it may be an untapped resource for PCa biomarkers or therapeutic targets.
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10
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Huang Y, Zhu Q. Mechanisms Regulating Abnormal Circular RNA Biogenesis in Cancer. Cancers (Basel) 2021; 13:cancers13164185. [PMID: 34439339 PMCID: PMC8391333 DOI: 10.3390/cancers13164185] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 01/22/2023] Open
Abstract
Simple Summary Circular RNAs (circRNAs) are circular RNA molecules without a 5′ cap and a 3′ poly(A) tail structure, which play an important role in tumor development, invasion and metastasis, etc. However, the mechanism of circRNA dysregulation in cancer remains unclear. Different from the classic splicing of linear RNA, circRNA is formed by back-splicing and is regulated by many cis-acting elements and trans-acting proteins. Exploring how the dysregulation of cis-regulatory elements and trans-acting proteins in tumor cells affects the biogenesis of circRNA, which in turn affects the development and prognosis of cancer, is of great significance for circRNA to become a cancer biomarker and therapeutic target. Abstract Circular RNAs (circRNAs), which are a class of endogenous RNA with covalently closed loops, play important roles in epigenetic regulation of gene expression at both the transcriptional and post-transcriptional level. Accumulating evidence demonstrated that numerous circRNAs were abnormally expressed in tumors and their dysregulation was involved in the tumorigenesis and metastasis of cancer. Although the functional mechanisms of many circRNAs have been revealed, how circRNAs are dysregulated in cancer remains elusive. CircRNAs are generated by a “back-splicing” process, which is regulated by different cis-regulatory elements and trans-acting proteins. Therefore, how these cis and trans elements change during tumorigenesis and how they regulate the biogenesis of circRNAs in cancer are two questions that interest us. In this review, we summarized the pathways for the biogenesis of circRNAs; and then illustrated how circRNAs dysregulated in cancer by discussing the changes of cis-regulatory elements and trans-acting proteins that related to circRNA splicing and maturation in cancer.
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Affiliation(s)
| | - Qubo Zhu
- Correspondence: ; Tel.: +86-18670318650
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11
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Veepaschit J, Viswanathan A, Bordonné R, Grimm C, Fischer U. Identification and structural analysis of the Schizosaccharomyces pombe SMN complex. Nucleic Acids Res 2021; 49:7207-7223. [PMID: 33754639 PMCID: PMC8287938 DOI: 10.1093/nar/gkab158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 01/20/2023] Open
Abstract
The macromolecular SMN complex facilitates the formation of Sm-class ribonucleoproteins involved in mRNA processing (UsnRNPs). While biochemical studies have revealed key activities of the SMN complex, its structural investigation is lagging behind. Here we report on the identification and structural determination of the SMN complex from the lower eukaryote Schizosaccharomyces pombe, consisting of SMN, Gemin2, 6, 7, 8 and Sm proteins. The core of the SMN complex is formed by several copies of SMN tethered through its C-terminal alpha-helices arranged with alternating polarity. This creates a central platform onto which Gemin8 binds and recruits Gemins 6 and 7. The N-terminal parts of the SMN molecules extrude via flexible linkers from the core and enable binding of Gemin2 and Sm proteins. Our data identify the SMN complex as a multivalent hub where Sm proteins are collected in its periphery to allow their joining with UsnRNA.
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Affiliation(s)
- Jyotishman Veepaschit
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Aravindan Viswanathan
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier 34293, France
| | - Clemens Grimm
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg 97074, Germany
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12
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Wong DK, Stark MS, Rader SD, Fast NM. Characterization of Pre-mRNA Splicing and Spliceosomal Machinery in Porphyridium purpureum and Evolutionary Implications for Red Algae. J Eukaryot Microbiol 2021; 68:e12844. [PMID: 33569840 DOI: 10.1111/jeu.12844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/28/2021] [Accepted: 02/05/2021] [Indexed: 11/29/2022]
Abstract
Pre-mRNA splicing is a highly conserved eukaryotic process, but our understanding of it is limited by a historical focus on well-studied organisms such as humans and yeast. There is considerable diversity in mechanisms and components of pre-mRNA splicing, especially in lineages that have evolved under the pressures of genome reduction. The ancestor of red algae is thought to have undergone genome reduction prior to the lineage's radiation, resulting in overall gene and intron loss in extant groups. Previous studies on the extremophilic red alga Cyanidioschyzon merolae revealed an intron-sparse genome with a highly reduced spliceosome. To determine whether these features applied to other red algae, we investigated multiple aspects of pre-mRNA splicing in the mesophilic red alga Porphyridium purpureum. Through strand-specific RNA-Seq, we observed high levels of intron retention across a large number of its introns, and nearly half of the transcripts for these genes are not spliced at all. We also discovered a relationship between variability of 5' splice site sequences and levels of splicing. To further investigate the connections between intron retention and splicing machinery, we bioinformatically assembled the P. purpureum spliceosome, and biochemically verified the presence of snRNAs. While most other core spliceosomal components are present, our results suggest highly divergent or missing U1 snRNP proteins, despite the presence of an uncharacteristically long U1 snRNA. These unusual aspects highlight the diverse nature of pre-mRNA splicing that can be seen in lesser-studied eukaryotes, raising the importance of investigating fundamental eukaryotic processes outside of model organisms.
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Affiliation(s)
- Donald K Wong
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, BC, Canada
| | - Martha S Stark
- Department of Chemistry, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada
| | - Stephen D Rader
- Department of Chemistry, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada
| | - Naomi M Fast
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, BC, Canada
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13
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Frey K, Pucker B. Animal, Fungi, and Plant Genome Sequences Harbor Different Non-Canonical Splice Sites. Cells 2020; 9:E458. [PMID: 32085510 PMCID: PMC7072748 DOI: 10.3390/cells9020458] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/11/2020] [Accepted: 02/14/2020] [Indexed: 11/17/2022] Open
Abstract
Most protein-encoding genes in eukaryotes contain introns, which are interwoven with exons. Introns need to be removed from initial transcripts in order to generate the final messenger RNA (mRNA), which can be translated into an amino acid sequence. Precise excision of introns by the spliceosome requires conserved dinucleotides, which mark the splice sites. However, there are variations of the highly conserved combination of GT at the 5' end and AG at the 3' end of an intron in the genome. GC-AG and AT-AC are two major non-canonical splice site combinations, which have been known for years. Recently, various minor non-canonical splice site combinations were detected with numerous dinucleotide permutations. Here, we expand systematic investigations of non-canonical splice site combinations in plants across eukaryotes by analyzing fungal and animal genome sequences. Comparisons of splice site combinations between these three kingdoms revealed several differences, such as an apparently increased CT-AC frequency in fungal genome sequences. Canonical GT-AG splice site combinations in antisense transcripts are a likely explanation for this observation, thus indicating annotation errors. In addition, high numbers of GA-AG splice site combinations were observed in Eurytemoraaffinis and Oikopleuradioica. A variant in one U1 small nuclear RNA (snRNA) isoform might allow the recognition of GA as a 5' splice site. In depth investigation of splice site usage based on RNA-Seq read mappings indicates a generally higher flexibility of the 3' splice site compared to the 5' splice site across animals, fungi, and plants.
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Affiliation(s)
- Katharina Frey
- Genetics and Genomics of Plants, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany;
- Graduate School DILS, Bielefeld Institute for Bioinformatics Infrastructure (BIBI), Bielefeld University, 33615 Bielefeld, Germany
| | - Boas Pucker
- Genetics and Genomics of Plants, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany;
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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14
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Integrative Structural Biology of Protein-RNA Complexes. Structure 2020; 28:6-28. [DOI: 10.1016/j.str.2019.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/17/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022]
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15
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Subramania S, Gagné LM, Campagne S, Fort V, O'Sullivan J, Mocaer K, Feldmüller M, Masson JY, Allain FHT, Hussein SM, Huot MÉ. SAM68 interaction with U1A modulates U1 snRNP recruitment and regulates mTor pre-mRNA splicing. Nucleic Acids Res 2019; 47:4181-4197. [PMID: 30767021 PMCID: PMC6486544 DOI: 10.1093/nar/gkz099] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/14/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022] Open
Abstract
Src associated in mitosis (SAM68) plays major roles in regulating RNA processing events, such as alternative splicing and mRNA translation, implicated in several developmental processes. It was previously shown that SAM68 regulates the alternative splicing of the mechanistic target of rapamycin (mTor), but the mechanism regulating this process remains elusive. Here, we report that SAM68 interacts with U1 small nuclear ribonucleoprotein (U1 snRNP) to promote splicing at the 5′ splice site in intron 5 of mTor. We also show that this direct interaction is mediated through U1A, a core-component of U1snRNP. SAM68 was found to bind the RRM1 domain of U1A through its C-terminal tyrosine rich region (YY domain). Deletion of the U1A-SAM68 interaction domain or mutation in SAM68-binding sites in intron 5 of mTor abrogates U1A recruitment and 5′ splice site recognition by the U1 snRNP, leading to premature intron 5 termination and polyadenylation. Taken together, our results provide the first mechanistic study by which SAM68 modulates alternative splicing decision, by affecting U1 snRNP recruitment at 5′ splice sites.
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Affiliation(s)
- Suryasree Subramania
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Laurence M Gagné
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Sébastien Campagne
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Victoire Fort
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Julia O'Sullivan
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Karel Mocaer
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada
| | - Miki Feldmüller
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Jean-Yves Masson
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Frédéric H T Allain
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Samer M Hussein
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
| | - Marc-Étienne Huot
- Centre de recherche du CHU de Québec-Université Laval (axe Oncologie), Québec, QC G1R 3S3, Canada.,CRCHU de Québec - Axe Oncologie, Québec, QC G1R 3S3, Canada
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16
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Shim AR, Nap RJ, Huang K, Almassalha LM, Matusda H, Backman V, Szleifer I. Dynamic Crowding Regulates Transcription. Biophys J 2019; 118:2117-2129. [PMID: 31818468 DOI: 10.1016/j.bpj.2019.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/26/2019] [Accepted: 11/11/2019] [Indexed: 02/01/2023] Open
Abstract
The nuclear environment is highly crowded by biological macromolecules, including chromatin and mobile proteins, which alter the kinetics and efficiency of transcriptional machinery. These alterations have been described, both theoretically and experimentally, for steady-state crowding densities; however, temporal changes in crowding density ("dynamic crowding") have yet to be integrated with gene expression. Dynamic crowding is pertinent to nuclear biology because processes such as chromatin translocation and protein diffusion lend to highly mobile biological crowders. Therefore, to capture such dynamic crowding and investigate its influence on transcription, we employ a three-pronged, systems-molecular approach. A system of chemical reactions represents the transcription pathway, the rates of which are determined by molecular-scale simulations; Brownian dynamics and Monte Carlo simulations quantify protein diffusion and DNA-protein binding affinity, dependent on macromolecular density. Altogether, this approach shows that transcription depends critically on dynamic crowding as the gene expression resultant from dynamic crowding can be profoundly different than that of steady-state crowding. In fact, expression levels can display both amplification and suppression and are notably different for genes or gene populations with different chemical and structural properties. These properties can be exploited to impose circadian expression, which is asymmetric and varies in strength, or to explain expression in cells under biomechanical stress. Therefore, this work demonstrates that dynamic crowding nontrivially alters transcription kinetics and presents dynamic crowding within the bulk nuclear nanoenvironment as a novel regulatory framework for gene expression.
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Affiliation(s)
- Anne R Shim
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois
| | - Rikkert J Nap
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois
| | - Kai Huang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois
| | - Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Hiroaki Matusda
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois
| | - Igal Szleifer
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois; Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois; Department of Chemistry, Northwestern University, Evanston, Illinois.
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17
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Leitner A, Dorn G, Allain FHT. Combining Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR) Spectroscopy for Integrative Structural Biology of Protein-RNA Complexes. Cold Spring Harb Perspect Biol 2019; 11:11/7/a032359. [PMID: 31262947 DOI: 10.1101/cshperspect.a032359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Deciphering complex RNA-protein interactions on a (near-)atomic level is a hurdle that hinders advancing our understanding of fundamental processes in RNA metabolism and RNA-based gene regulation. To overcome challenges associated with individual structure determination methods, structural information derived from complementary biophysical methods can be combined in integrative structural biology approaches. Here, we review recent advances in such hybrid structural approaches with a focus on combining mass spectrometric analysis of cross-linked protein-RNA complexes and nuclear magnetic resonance (NMR) spectroscopy.
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Affiliation(s)
- Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093 Zürich, Switzerland
| | - Georg Dorn
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
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18
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Beattie CE, Kolb SJ. Spinal muscular atrophy: Selective motor neuron loss and global defect in the assembly of ribonucleoproteins. Brain Res 2018; 1693:92-97. [DOI: 10.1016/j.brainres.2018.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/10/2018] [Accepted: 02/15/2018] [Indexed: 12/13/2022]
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19
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Dou N, Yang D, Yu S, Wu B, Gao Y, Li Y. SNRPA enhances tumour cell growth in gastric cancer through modulating NGF expression. Cell Prolif 2018; 51:e12484. [PMID: 30039889 DOI: 10.1111/cpr.12484] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/22/2018] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES SNRPA is a protein component of U1 small nuclear ribonucleoprotein (U1 snRNP) complex, which takes part in the splicing of pre-mRNAs. Its expression and function in tumour remain unknown. Herein, we elucidated the functional contribution of SNRPA to the progression of gastric cancer (GC). MATERIALS AND METHODS SNRPA expression was investigated in a GC tissue microarray by immunohistochemical staining. Cell proliferation was evaluated by CCK-8, colony formation and EdU incorporation assays. A mouse xenograft model was used to detect the tumourigenicity. Gene expression profiling was performed and then the potential target genes were verified by quantitative real-time PCR and western blot analyses. The functional relevance between SNRPA and its target gene was examined by cell growth assays. RESULTS SNRPA expression was higher in tumour tissues than in matched normal gastric mucosa tissues, and it was positively correlated with the tumour size and progression. High SNRPA expression indicated poor prognosis of GC patients. Silencing SNRPA in GC cells markedly inhibited cell proliferation in vitro and tumour growth in a xenograft model, while overexpressing SNRPA exhibited opposite results. Moreover, we identified NGF (Nerve growth factor) as a downstream effector of SNRPA and further proved that NGF was crucial for SNRPA-mediated GC cell growth. CONCLUSIONS These findings suggested that SNRPA may contribute to GC progression via NGF and could be a prognostic biomarker for GC.
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Affiliation(s)
- Ning Dou
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dong Yang
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shijun Yu
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Binghao Wu
- Harvard Medical School, Massachusetts General Hospital, Cutaneous Biology Research Center, Charlestown, MA, USA
| | - Yong Gao
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yandong Li
- Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Shanghai East Hospital, Research Center for Translational Medicine, Tongji University School of Medicine, Shanghai, China
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20
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Thompson LW, Morrison KD, Shirran SL, Groen EJN, Gillingwater TH, Botting CH, Sleeman JE. Neurochondrin interacts with the SMN protein suggesting a novel mechanism for spinal muscular atrophy pathology. J Cell Sci 2018; 131:jcs.211482. [PMID: 29507115 PMCID: PMC5963842 DOI: 10.1242/jcs.211482] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an inherited neurodegenerative condition caused by a reduction in the amount of functional survival motor neuron (SMN) protein. SMN has been implicated in transport of mRNA in neural cells for local translation. We previously identified microtubule-dependent mobile vesicles rich in SMN and SNRPB, a member of the Sm family of small nuclear ribonucleoprotein (snRNP)-associated proteins, in neural cells. By comparing the interactomes of SNRPB and SNRPN, a neural-specific Sm protein, we now show that the essential neural protein neurochondrin (NCDN) interacts with Sm proteins and SMN in the context of mobile vesicles in neurites. NCDN has roles in protein localisation in neural cells and in maintenance of cell polarity. NCDN is required for the correct localisation of SMN, suggesting they may both be required for formation and transport of trafficking vesicles. NCDN may have potential as a therapeutic target for SMA together with, or in place of the targeting of SMN expression. This article has an associated First Person interview with the first author of the paper. Highlighted Article: The essential neural protein neurochondrin interacts with the spinal muscular atrophy (SMA) protein SMN in cell lines and in mice. This might be relevant to the molecular pathology of SMA.
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Affiliation(s)
- Luke W Thompson
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Kim D Morrison
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Sally L Shirran
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Ewout J N Groen
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School, Biomedical Sciences and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Catherine H Botting
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
| | - Judith E Sleeman
- School of Biology, University of St Andrews, BSRC Complex, North Haugh St Andrews, KY16 9ST, UK
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21
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Jiang D, Zou X, Zhang C, Chen J, Li Z, Wang Y, Deng Z, Wang L, Chen S. Gemin5 plays a role in unassembled-U1 snRNA disposal in SMN-deficient cells. FEBS Lett 2018. [PMID: 29537490 DOI: 10.1002/1873-3468.13031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Gemin5 acts as a U1 small nuclear RNA (snRNA)-binding protein in U1 small nuclear ribonucleic protein (snRNP) biogenesis. Here, we report a role for Gemin5 in unassembled U1 snRNP disposal under survival of motor neuron (SMN) protein-deficient conditions. We demonstrate that non-Sm protein-associated U1 snRNA and U1A are enriched in cytoplasmic granules and colocalize to P bodies in SMN-deficient cells. Immunoprecipitation assays show increased associations of the U1 snRNP component U1A with P body components and Gemin5 in SMN-deficient cells. More importantly, Gemin5 knockdown eliminates the unassembled U1 snRNP granules and rescues U1 snRNA levels in SMN-deficient cells. Taken together, our study provides direct evidence that Gemin5 is involved in unassembled-U1 snRNA disposal under conditions of SMN deficiency.
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Affiliation(s)
- Dongxu Jiang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
- Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Xuan Zou
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Cheng Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Jincao Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Zhiqiang Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Yunfu Wang
- Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Liangrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
| | - Shi Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, and Brain Center, Zhongnan Hospital, Wuhan University, China
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22
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Alternative Splicing in Genetic Diseases: Improved Diagnosis and Novel Treatment Options. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 335:85-141. [PMID: 29305015 DOI: 10.1016/bs.ircmb.2017.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alternative splicing is an important mechanism to regulate gene expression and to expand the repertoire of gene products in order to accommodate an increase in complexity of multicellular organisms. It needs to be precisely regulated, which is achieved via RNA structure, splicing factors, transcriptional regulation, and chromatin. Changes in any of these factors can lead to disease. These may include the core spliceosome, splicing enhancer/repressor sequences and their interacting proteins, the speed of transcription by RNA polymerase II, and histone modifications. While the basic principle of splicing is well understood, it is still very difficult to predict splicing outcome, due to the multiple levels of regulation. Current molecular diagnostics mainly uses Sanger sequencing of exons, or next-generation sequencing of gene panels or the whole exome. Functional analysis of potential splicing variants is scarce, and intronic variants are often not considered. This likely results in underestimation of the percentage of splicing variants. Understanding how sequence variants may affect splicing is not only crucial for confirmation of diagnosis and for genetic counseling, but also for the development of novel treatment options. These include small molecules, transsplicing, antisense oligonucleotides, and gene therapy. Here we review the current state of molecular mechanisms of splicing regulation and how deregulation can lead to human disease, diagnostics to detect splicing variants, and novel treatment options based on splicing correction.
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23
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Gruss OJ, Meduri R, Schilling M, Fischer U. UsnRNP biogenesis: mechanisms and regulation. Chromosoma 2017; 126:577-593. [PMID: 28766049 DOI: 10.1007/s00412-017-0637-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 12/24/2022]
Abstract
Macromolecular complexes composed of proteins or proteins and nucleic acids rather than individual macromolecules mediate many cellular activities. Maintenance of these activities is essential for cell viability and requires the coordinated production of the individual complex components as well as their faithful incorporation into functional entities. Failure of complex assembly may have fatal consequences and can cause severe diseases. While many macromolecular complexes can form spontaneously in vitro, they often require aid from assembly factors including assembly chaperones in the crowded cellular environment. The assembly of RNA protein complexes implicated in the maturation of pre-mRNAs (termed UsnRNPs) has proven to be a paradigm to understand the action of assembly factors and chaperones. UsnRNPs are assembled by factors united in protein arginine methyltransferase 5 (PRMT5)- and survival motor neuron (SMN)-complexes, which act sequentially in the UsnRNP production line. While the PRMT5-complex pre-arranges specific sets of proteins into stable intermediates, the SMN complex displaces assembly factors from these intermediates and unites them with UsnRNA to form the assembled RNP. Despite advanced mechanistic understanding of UsnRNP assembly, our knowledge of regulatory features of this essential and ubiquitous cellular function remains remarkably incomplete. One may argue that the process operates as a default biosynthesis pathway and does not require sophisticated regulatory cues. Simple theoretical considerations and a number of experimental data, however, indicate that regulation of UsnRNP assembly most likely happens at multiple levels. This review will not only summarize how individual components of this assembly line act mechanistically but also why, how, and when the UsnRNP workflow might be regulated by means of posttranslational modification in response to cellular signaling cues.
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Affiliation(s)
- Oliver J Gruss
- Department of Genetics, Rheinische Friedrich-Wilhelms-Universität Bonn, Karlrobert-Kreiten-Str. 13, 53115, Bonn, Germany.
| | - Rajyalakshmi Meduri
- Department of Biochemistry, University of Würzburg, Biozentrum, Am Hubland, D-97074, Würzburg, Germany
| | - Maximilian Schilling
- Department of Genetics, Rheinische Friedrich-Wilhelms-Universität Bonn, Karlrobert-Kreiten-Str. 13, 53115, Bonn, Germany
| | - Utz Fischer
- Department of Biochemistry, University of Würzburg, Biozentrum, Am Hubland, D-97074, Würzburg, Germany.
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24
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Prusty AB, Meduri R, Prusty BK, Vanselow J, Schlosser A, Fischer U. Impaired spliceosomal UsnRNP assembly leads to Sm mRNA down-regulation and Sm protein degradation. J Cell Biol 2017. [PMID: 28637748 PMCID: PMC5551706 DOI: 10.1083/jcb.201611108] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cellular spliceosomal UsnRNP assembly is assisted by the PRMT5 and SMN complexes. Prusty et al. demonstrate that perturbations in the assembly machinery of UsnRNPs trigger complex cellular responses, using ribosomes, exosome-mediated RNA degradation, and autophagy to prevent Sm protein aggregation. Specialized assembly factors facilitate the formation of many macromolecular complexes in vivo. The formation of Sm core structures of spliceosomal U-rich small nuclear ribonucleoprotein particles (UsnRNPs) requires assembly factors united in protein arginine methyltransferase 5 (PRMT5) and survival motor neuron (SMN) complexes. We demonstrate that perturbations of this assembly machinery trigger complex cellular responses that prevent aggregation of unassembled Sm proteins. Inactivation of the SMN complex results in the initial tailback of Sm proteins on the PRMT5 complex, followed by down-regulation of their encoding mRNAs. In contrast, reduction of pICln, a PRMT5 complex subunit, leads to the retention of newly synthesized Sm proteins on ribosomes and their subsequent lysosomal degradation. Overexpression of Sm proteins under these conditions results in a surplus of Sm proteins over pICln, promoting their aggregation. Our studies identify an elaborate safeguarding system that prevents individual Sm proteins from aggregating, contributing to cellular UsnRNP homeostasis.
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Affiliation(s)
| | - Rajyalakshmi Meduri
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Bhupesh Kumar Prusty
- Department of Microbiology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Jens Vanselow
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Andreas Schlosser
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Utz Fischer
- Department of Biochemistry, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany .,Department of Radiation Medicine and Applied Sciences, University of California at San Diego, San Diego, CA
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25
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Huang S, Balgi A, Pan Y, Li M, Zhang X, Du L, Zhou M, Roberge M, Li X. Identification of Methylosome Components as Negative Regulators of Plant Immunity Using Chemical Genetics. MOLECULAR PLANT 2016; 9:1620-1633. [PMID: 27756575 DOI: 10.1016/j.molp.2016.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/01/2016] [Accepted: 10/01/2016] [Indexed: 06/06/2023]
Abstract
Nucleotide-binding leucine-rich repeat (NLR) proteins serve as immune receptors in both plants and animals. To identify components required for NLR-mediated immunity, we designed and carried out a chemical genetics screen to search for small molecules that can alter immune responses in Arabidopsis thaliana. From 13 600 compounds, we identified Ro 8-4304 that was able to specifically suppress the severe autoimmune phenotypes of chs3-2D (chilling sensitive 3, 2D), including the arrested growth morphology and heightened PR (Pathogenesis Related) gene expression. Further, six Ro 8-4304 insensitive mutants were uncovered from the Ro 8-4304-insensitive mutant (rim) screen using a mutagenized chs3-2D population. Positional cloning revealed that rim1 encodes an allele of AtICln (I, currents; Cl, chloride; n, nucleotide). Genetic and biochemical analysis demonstrated that AtICln is in the same protein complex with the methylosome components small nuclear ribonucleoprotein D3b (SmD3b) and protein arginine methyltransferase 5 (PRMT5), which are required for the biogenesis of small nuclear ribonucleoproteins (snRNPs) involved in mRNA splicing. Double mutant analysis revealed that SmD3b is also involved in the sensitivity to Ro 8-4304, and the prmt5-1 chs3-2D double mutant is lethal. Loss of AtICln, SmD3b, or PRMT5 function results in enhanced disease resistance against the virulent oomycete pathogen Hyaloperonospora arabidopsidis Noco2, suggesting that mRNA splicing plays a previously unknown negative role in plant immunity. The successful implementation of a high-throughput chemical genetic screen and the identification of a small-molecule compound affecting plant immunity indicate that chemical genetics is a powerful tool to study whole-organism plant defense pathways.
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Affiliation(s)
- Shuai Huang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Aruna Balgi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Yaping Pan
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Meng Li
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Xiaoran Zhang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Lilin Du
- National Institute of Biological Sciences, Beijing 102206, China
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michel Roberge
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
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26
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Doedens JR, Jones WD, Hill K, Mason MJ, Gersuk VH, Mease PJ, Dall'Era M, Aranow C, Martin RW, Cohen SB, Fleischmann RM, Kivitz AJ, Burge DJ, Chaussabel D, Elkon KB, Posada JA. Blood-Borne RNA Correlates with Disease Activity and IFN-Stimulated Gene Expression in Systemic Lupus Erythematosus. THE JOURNAL OF IMMUNOLOGY 2016; 197:2854-63. [PMID: 27534558 DOI: 10.4049/jimmunol.1601142] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 07/26/2016] [Indexed: 12/27/2022]
Abstract
The loss of tolerance and the presence of circulating autoantibodies directed against nuclear Ags is the hallmark of systemic lupus erythematosus (SLE). Many of these Ags are complexed with short, noncoding RNAs, such as U1 and Y1. The amount of U1 and Y1 RNA complexed with SLE patient Abs and immune complexes was measured in a cross-section of 228 SLE patients to evaluate the role of these RNA molecules within the known biochemical framework of SLE. The study revealed that SLE patients had significantly elevated levels of circulating U1 and/or Y1 RNA compared with healthy volunteers. In addition, the blood-borne RNA molecules were correlated with SLE disease activity and increased expression of IFN-inducible genes. To our knowledge, this study provides the first systematic examination of the role of circulating RNA in a large group of SLE patients and provides an important link with IFN dysregulation.
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Affiliation(s)
| | | | - Kay Hill
- PlasmaLab International, Everett, WA 98201
| | | | | | - Philip J Mease
- Swedish Medical Center and University of Washington, Seattle, WA 98122
| | - Maria Dall'Era
- University of California, San Francisco, San Francisco, CA 94143
| | - Cynthia Aranow
- The Feinstein Institute for Medical Research, Manhasset, NY 11030
| | - Richard W Martin
- College of Human Medicine, Michigan State University, East Lansing, MI 48824
| | | | | | - Alan J Kivitz
- Altoona Center for Clinical Research, Duncansville, PA 16635
| | | | - Damien Chaussabel
- Benaroya Research Institute, Seattle, WA 98101; Sidra Medical and Research Center, Doha, Qatar; and
| | - Keith B Elkon
- Department of Rheumatology, University of Washington, Seattle, WA 98109
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27
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Rakesh R, Joseph AP, Bhaskara RM, Srinivasan N. Structural and mechanistic insights into human splicing factor SF3b complex derived using an integrated approach guided by the cryo-EM density maps. RNA Biol 2016; 13:1025-1040. [PMID: 27618338 DOI: 10.1080/15476286.2016.1218590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Pre-mRNA splicing in eukaryotes is performed by the spliceosome, a highly complex macromolecular machine. SF3b is a multi-protein complex which recognizes the branch point adenosine of pre-mRNA as part of a larger U2 snRNP or U11/U12 di-snRNP in the dynamic spliceosome machinery. Although a cryo-EM map is available for human SF3b complex, the structure and relative spatial arrangement of all components in the complex are not yet known. We have recognized folds of domains in various proteins in the assembly and generated comparative models. Using an integrative approach involving structural and other experimental data, guided by the available cryo-EM density map, we deciphered a pseudo-atomic model of the closed form of SF3b which is found to be a "fuzzy complex" with highly flexible components and multiplicity of folds. Further, the model provides structural information for 5 proteins (SF3b10, SF3b155, SF3b145, SF3b130 and SF3b14b) and localization information for 4 proteins (SF3b10, SF3b145, SF3b130 and SF3b14b) in the assembly for the first time. Integration of this model with the available U11/U12 di-snRNP cryo-EM map enabled elucidation of an open form. This now provides new insights on the mechanistic features involved in the transition between closed and open forms pivoted by a hinge region in the SF3b155 protein that also harbors cancer causing mutations. Moreover, the open form guided model of the 5' end of U12 snRNA, which includes the branch point duplex, shows that the architecture of SF3b acts as a scaffold for U12 snRNA: pre-mRNA branch point duplex formation with potential implications for branch point adenosine recognition fidelity.
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Affiliation(s)
- Ramachandran Rakesh
- a Molecular Biophysics Unit, Indian Institute of Science , Bangalore , India
| | - Agnel Praveen Joseph
- b National Center for Biological Sciences, TIFR, GKVK Campus , Bangalore , India
| | - Ramachandra M Bhaskara
- a Molecular Biophysics Unit, Indian Institute of Science , Bangalore , India.,b National Center for Biological Sciences, TIFR, GKVK Campus , Bangalore , India
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28
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Sperling R. The nuts and bolts of the endogenous spliceosome. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27465259 DOI: 10.1002/wrna.1377] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 01/09/2023]
Abstract
The complex life of pre-mRNA from transcription to the production of mRNA that can be exported from the nucleus to the cytoplasm to encode for proteins entails intricate coordination and regulation of a network of processing events. Coordination is required between transcription and splicing and between several processing events including 5' and 3' end processing, splicing, alternative splicing and editing that are major contributors to the diversity of the human proteome, and occur within a huge and dynamic macromolecular machine-the endogenous spliceosome. Detailed mechanistic insight of the splicing reaction was gained from studies of the in vitro spliceosome assembled on a single intron. Because most pre-mRNAs are multiintronic that undergo alternative splicing, the in vivo splicing machine requires additional elements to those of the in vitro machine, to account for all these diverse functions. Information about the endogenous spliceosome is emerging from imaging studies in intact and live cells that support the cotranscriptional commitment to splicing model and provide information about splicing kinetics in vivo. Another source comes from studies of the in vivo assembled spliceosome, isolated from cell nuclei under native conditions-the supraspliceosome-that individually package pre-mRNA transcripts of different sizes and number of introns into complexes of a unique structure, indicating their universal nature. Recent years have portrayed new players affecting alternative splicing and novel connections between splicing, transcription and chromatin. The challenge ahead is to elucidate the structure and function of the endogenous spliceosome and decipher the regulation and coordination of its network of processing activities. WIREs RNA 2017, 8:e1377. doi: 10.1002/wrna.1377 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ruth Sperling
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem, Israel
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29
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Loveland AB, Bah E, Madireddy R, Zhang Y, Brilot AF, Grigorieff N, Korostelev AA. Ribosome•RelA structures reveal the mechanism of stringent response activation. eLife 2016; 5. [PMID: 27434674 PMCID: PMC4974054 DOI: 10.7554/elife.17029] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/18/2016] [Indexed: 12/18/2022] Open
Abstract
Stringent response is a conserved bacterial stress response underlying virulence and antibiotic resistance. RelA/SpoT-homolog proteins synthesize transcriptional modulators (p)ppGpp, allowing bacteria to adapt to stress. RelA is activated during amino-acid starvation, when cognate deacyl-tRNA binds to the ribosomal A (aminoacyl-tRNA) site. We report four cryo-EM structures of E. coli RelA bound to the 70S ribosome, in the absence and presence of deacyl-tRNA accommodating in the 30S A site. The boomerang-shaped RelA with a wingspan of more than 100 Å wraps around the A/R (30S A-site/RelA-bound) tRNA. The CCA end of the A/R tRNA pins the central TGS domain against the 30S subunit, presenting the (p)ppGpp-synthetase domain near the 30S spur. The ribosome and A/R tRNA are captured in three conformations, revealing hitherto elusive states of tRNA engagement with the ribosomal decoding center. Decoding-center rearrangements are coupled with the step-wise 30S-subunit 'closure', providing insights into the dynamics of high-fidelity tRNA decoding.
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Affiliation(s)
- Anna B Loveland
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry, Brandeis University, Waltham, United States.,Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, United States
| | - Eugene Bah
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Rohini Madireddy
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Ying Zhang
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
| | - Axel F Brilot
- Department of Biochemistry, Brandeis University, Waltham, United States.,Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, United States
| | - Nikolaus Grigorieff
- Department of Biochemistry, Brandeis University, Waltham, United States.,Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, United States.,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Andrei A Korostelev
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, United States.,Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, United States
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30
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Johnová P, Skalák J, Saiz-Fernández I, Brzobohatý B. Plant responses to ambient temperature fluctuations and water-limiting conditions: A proteome-wide perspective. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:916-31. [PMID: 26861773 DOI: 10.1016/j.bbapap.2016.02.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/26/2015] [Accepted: 02/04/2016] [Indexed: 12/24/2022]
Abstract
BACKGROUND Every year, environmental stresses such as limited water and nutrient availability, salinity, and temperature fluctuations inflict significant losses on crop yields across the globe. Recently, developments in analytical techniques, e.g. mass spectrometry, have led to great advances towards understanding how plants respond to environmental stresses. These processes are mediated by many molecular pathways and, at least partially, via proteome-environment interactions. SCOPE OF REVIEW This review focuses on the current state of knowledge about interactions between the plant proteome and the environment, with a special focus on drought and temperature responses of plant proteome dynamics, and subcellular and organ-specific compartmentalization, in Arabidopsis thaliana and crop species. MAJOR CONCLUSIONS Correct plant development under non-optimal conditions requires complex self-protection mechanisms, many of them common to different abiotic stresses. Proteome analyses of plant responses to temperature and drought stresses have revealed an intriguing interplay of modifications, mainly affecting the photosynthetic machinery, carbohydrate metabolism, and ROS activation and scavenging. Imbalances between transcript-level and protein-level regulation observed during adaptation to abiotic stresses suggest that many of the regulatory processes are controlled at translational and post-translational levels; proteomics is thus essential in revealing important regulatory networks. GENERAL SIGNIFICANCE Because information from proteomic data extends far beyond what can be deduced from transcriptome analysis, the results of proteome studies have substantially deepened our understanding of stress adaptation in plants; this is clearly a prerequisite for designing strategies to improve the yield and quality of crops grown under unfavorable conditions brought about by ongoing climatic change. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock.
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Affiliation(s)
- Patricie Johnová
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, v.v.i. and, Mendel University in Brno, CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic.
| | - Jan Skalák
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, v.v.i. and, Mendel University in Brno, CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic.
| | - Iñigo Saiz-Fernández
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, v.v.i. and, Mendel University in Brno, CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic.
| | - Břetislav Brzobohatý
- Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, v.v.i. and, Mendel University in Brno, CEITEC - Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, CZ-613 00 Brno, Czech Republic.
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31
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Yang F, Xu D, Zhuang Y, Yi X, Huang Y, Chen H, Lin S, Campbell DA, Sturm NR, Liu G, Zhang H. Spliced leader RNA trans-splicing discovered in copepods. Sci Rep 2015; 5:17411. [PMID: 26621068 PMCID: PMC4664967 DOI: 10.1038/srep17411] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/29/2015] [Indexed: 11/13/2022] Open
Abstract
Copepods are one of the most abundant metazoans in the marine ecosystem, constituting a critical link in aquatic food webs and contributing significantly to the global carbon budget, yet molecular mechanisms of their gene expression are not well understood. Here we report the detection of spliced leader (SL) trans-splicing in calanoid copepods. We have examined nine species of wild-caught copepods from Jiaozhou Bay, China that represent the major families of the calanoids. All these species contained a common 46-nt SL (CopepodSL). We further determined the size of CopepodSL precursor RNA (slRNA; 108-158 nt) through genomic analysis and 3′-RACE technique, which was confirmed by RNA blot analysis. Structure modeling showed that the copepod slRNA folded into typical slRNA secondary structures. Using a CopepodSL-based primer set, we selectively enriched and sequenced copepod full-length cDNAs, which led to the characterization of copepod transcripts and the cataloging of the complete set of 79 eukaryotic cytoplasmic ribosomal proteins (cRPs) for a single copepod species. We uncovered the SL trans-splicing in copepod natural populations, and demonstrated that CopepodSL was a sensitive and specific tool for copepod transcriptomic studies at both the individual and population levels and that it would be useful for metatranscriptomic analysis of copepods.
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Affiliation(s)
- Feifei Yang
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Donghui Xu
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yunyun Zhuang
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Xiaoyan Yi
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yousong Huang
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Hongju Chen
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, USA
| | - David A Campbell
- Department of Microbiology, Immunology &Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Nancy R Sturm
- Department of Microbiology, Immunology &Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Guangxing Liu
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Huan Zhang
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China.,College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.,Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, USA
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32
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Rigo N, Sun C, Fabrizio P, Kastner B, Lührmann R. Protein localisation by electron microscopy reveals the architecture of the yeast spliceosomal B complex. EMBO J 2015; 34:3059-73. [PMID: 26582754 DOI: 10.15252/embj.201592022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/19/2015] [Indexed: 12/20/2022] Open
Abstract
The spliceosome assembles on a pre-mRNA intron by binding of five snRNPs and numerous proteins, leading to the formation of the pre-catalytic B complex. While the general morphology of the B complex is known, the spatial arrangement of proteins and snRNP subunits within it remain to be elucidated. To shed light on the architecture of the yeast B complex, we immuno-labelled selected proteins and located them by negative-stain electron microscopy. The B complex exhibited a triangular shape with main body, head and neck domains. We located the U5 snRNP components Brr2 at the top and Prp8 and Snu114 in the centre of the main body. We found several U2 SF3a (Prp9 and Prp11) and SF3b (Hsh155 and Cus1) proteins in the head domain and two U4/U6 snRNP proteins (Prp3 and Lsm4) in the neck domain that connects the main body with the head. Thus, we could assign distinct domains of the B complex to the respective snRNPs and provide the first detailed picture of the subunit architecture and protein arrangements of the B complex.
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Affiliation(s)
- Norbert Rigo
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Chengfu Sun
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Patrizia Fabrizio
- 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
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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33
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Tagoe CE. The transcription, translation, transport-trail and autoimmunity: Guilt by association. Med Hypotheses 2015; 85:744-8. [PMID: 26519101 DOI: 10.1016/j.mehy.2015.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 10/16/2015] [Indexed: 10/22/2022]
Abstract
The autoimmune connective tissue diseases (ACTD) are a group of diseases which share clinical features and genetic inheritance. They are characterized by systemic autoimmunity and autoantibody production with a striking predilection for cellular components involved in transcription, translation and cellular transport. Although multiple triggers of autoimmunity have been proposed for this group of diseases including microbial agents such as viruses and bacteria, drugs, ultraviolet light, environmental toxins, stress, hormones and heavy metals, the prominence of autoantibodies to components of the transcription, translation, cellular transport-trail (TTTT) suggests that the agent(s) triggering the autoimmune response potentially utilize the TTTT. For the ACTD, viruses and viral agents are the likely triggers of autoimmunity as a result of aberrant viral latency with the production of autoantibodies to the components of the cellular TTTT machinery through multiple mechanisms, perhaps including molecular mimicry, bystander activation and epitope spreading.
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Affiliation(s)
- Clement E Tagoe
- Department of Medicine, Division of Rheumatology, Albert Einstein College of Medicine, Bronx, NY, United States.
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34
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Workman E, Kalda C, Patel A, Battle DJ. Gemin5 Binds to the Survival Motor Neuron mRNA to Regulate SMN Expression. J Biol Chem 2015; 290:15662-15669. [PMID: 25911097 PMCID: PMC4505476 DOI: 10.1074/jbc.m115.646257] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/22/2015] [Indexed: 12/21/2022] Open
Abstract
Reduced expression of SMN causes spinal muscular atrophy, a severe neurodegenerative disease. Despite the importance of maintaining SMN levels, relatively little is known about the mechanisms by which SMN levels are regulated. We show here that Gemin5, the snRNA-binding protein of the SMN complex, binds directly to the SMN mRNA and regulates SMN expression. Gemin5 binds with high specificity, both in vitro and in vivo, to sequence and structural elements in the SMN mRNA 3'-untranslated region that are reminiscent of the snRNP code to which Gemin5 binds on snRNAs. Reduction of Gemin5 redistributes the SMN mRNA from heavy polysomes to lighter polysomes and monosomes, suggesting that Gemin5 functions as an activator of SMN translation. SMN protein is not stoichiometrically present on the SMN mRNA with Gemin5, but the mRNA-binding activity of Gemin5 is dependent on SMN levels, providing a feedback mechanism for SMN to regulate its own expression via Gemin5. This work both reveals a new autoregulatory pathway governing SMN expression, and identifies a new mechanism through which SMN can modulate specific mRNA expression via Gemin5.
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Affiliation(s)
- Eileen Workman
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210
| | - Caitlin Kalda
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210
| | - Aalapi Patel
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210
| | - Daniel J Battle
- Department of Molecular and Cellular Biochemistry, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210; Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210.
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35
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Systematic discovery of Xist RNA binding proteins. Cell 2015; 161:404-16. [PMID: 25843628 DOI: 10.1016/j.cell.2015.03.025] [Citation(s) in RCA: 732] [Impact Index Per Article: 81.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/29/2015] [Accepted: 03/11/2015] [Indexed: 12/15/2022]
Abstract
Noncoding RNAs (ncRNAs) function with associated proteins to effect complex structural and regulatory outcomes. To reveal the composition and dynamics of specific noncoding RNA-protein complexes (RNPs) in vivo, we developed comprehensive identification of RNA binding proteins by mass spectrometry (ChIRP-MS). ChIRP-MS analysis of four ncRNAs captures key protein interactors, including a U1-specific link to the 3' RNA processing machinery. Xist, an essential lncRNA for X chromosome inactivation (XCI), interacts with 81 proteins from chromatin modification, nuclear matrix, and RNA remodeling pathways. The Xist RNA-protein particle assembles in two steps coupled with the transition from pluripotency to differentiation. Specific interactors include HnrnpK, which participates in Xist-mediated gene silencing and histone modifications but not Xist localization, and Drosophila Split ends homolog Spen, which interacts via the A-repeat domain of Xist and is required for gene silencing. Thus, Xist lncRNA engages with proteins in a modular and developmentally controlled manner to coordinate chromatin spreading and silencing.
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36
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Sharma S, Wongpalee SP, Vashisht A, Wohlschlegel JA, Black DL. Stem-loop 4 of U1 snRNA is essential for splicing and interacts with the U2 snRNP-specific SF3A1 protein during spliceosome assembly. Genes Dev 2015; 28:2518-31. [PMID: 25403181 PMCID: PMC4233244 DOI: 10.1101/gad.248625.114] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pairing of 5′ and 3′ splice sites across an intron is a critical step in spliceosome formation and its regulation. Sharma et al. report a new interaction between stem–loop 4 (SL4) of the U1 snRNA, which recognizes the 5′ splice, and a component of the U2 snRNP complex, which assembles across the intron at the 3′ splice site. U1-SL4 interacts with the SF3A1 protein of the U2 snRNP, and this interaction occurs within prespliceosomal complexes assembled on the pre-mRNA. The pairing of 5′ and 3′ splice sites across an intron is a critical step in spliceosome formation and its regulation. Interactions that bring the two splice sites together during spliceosome assembly must occur with a high degree of specificity and fidelity to allow expression of functional mRNAs and make particular alternative splicing choices. Here, we report a new interaction between stem–loop 4 (SL4) of the U1 snRNA, which recognizes the 5′ splice site, and a component of the U2 small nuclear ribonucleoprotein particle (snRNP) complex, which assembles across the intron at the 3′ splice site. Using a U1 snRNP complementation assay, we found that SL4 is essential for splicing in vivo. The addition of free U1-SL4 to a splicing reaction in vitro inhibits splicing and blocks complex assembly prior to formation of the prespliceosomal A complex, indicating a requirement for a SL4 contact in spliceosome assembly. To characterize the interactions of this RNA structure, we used a combination of stable isotope labeling by amino acids in cell culture (SILAC), biotin/Neutravidin affinity pull-down, and mass spectrometry. We show that U1-SL4 interacts with the SF3A1 protein of the U2 snRNP. We found that this interaction between the U1 snRNA and SF3A1 occurs within prespliceosomal complexes assembled on the pre-mRNA. Thus, SL4 of the U1 snRNA is important for splicing, and its interaction with SF3A1 mediates contact between the 5′ and 3′ splice site complexes within the assembling spliceosome.
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Affiliation(s)
- Shalini Sharma
- Department of Basic Medical Sciences, University of Arizona, College of Medicine-Phoenix, Phoenix, Arizona 85004, USA; Department of Microbiology, Immunology, and Molecular Genetics
| | | | | | | | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, California 90095, USA
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37
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Husedzinovic A, Neumann B, Reymann J, Draeger-Meurer S, Chari A, Erfle H, Fischer U, Gruss OJ. The catalytically inactive tyrosine phosphatase HD-PTP/PTPN23 is a novel regulator of SMN complex localization. Mol Biol Cell 2014; 26:161-71. [PMID: 25392300 PMCID: PMC4294665 DOI: 10.1091/mbc.e14-06-1151] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This first systematic and comprehensive screen of human phosphatases for a regulatory role in the survival motor neuron (SMN) complex identifies the catalytically inactive, non–receptor-type tyrosine phosphatase PTPN23/HD-PTP as a novel SMN complex regulator. PTPN23 maintains a highly phosphorylated state of SMN, which is important for its function in snRNP assembly. The survival motor neuron (SMN) complex fulfils essential functions in the assembly of snRNPs, which are key components in the splicing of pre-mRNAs. Little is known about the regulation of SMN complex activity by posttranslational modification despite its complicated phosphorylation pattern. Several phosphatases had been implicated in the regulation of SMN, including the nuclear phosphatases PPM1G and PP1γ. Here we systematically screened all human phosphatase gene products for a regulatory role in the SMN complex. We used the accumulation of SMN in Cajal bodies of intact proliferating cells, which actively assemble snRNPs, as a readout for unperturbed SMN complex function. Knockdown of 29 protein phosphatases interfered with SMN accumulation in Cajal bodies, suggesting impaired SMN complex function, among those the catalytically inactive, non–receptor-type tyrosine phosphatase PTPN23/HD-PTP. Knockdown of PTPN23 also led to changes in the phosphorylation pattern of SMN without affecting the assembly of the SMN complex. We further show interaction between SMN and PTPN23 and document that PTPN23, like SMN, shuttles between nucleus and cytoplasm. Our data provide the first comprehensive screen for SMN complex regulators and establish a novel regulatory function of PTPN23 in maintaining a highly phosphorylated state of SMN, which is important for its proper function in snRNP assembly.
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Affiliation(s)
- Alma Husedzinovic
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Beate Neumann
- European Molecular Biology Laboratory, Advanced Light Microscopy Facility Programme, D-69117 Heidelberg, Germany
| | - Jürgen Reymann
- ViroQuant-CellNetworks RNAi Screening Facility, BioQuant Centre, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Stefanie Draeger-Meurer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Ashwin Chari
- Theodor Boveri Institute, Biocenter of the University of Würzburg, D-97074 Würzburg, Germany
| | - Holger Erfle
- ViroQuant-CellNetworks RNAi Screening Facility, BioQuant Centre, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Utz Fischer
- Theodor Boveri Institute, Biocenter of the University of Würzburg, D-97074 Würzburg, Germany
| | - Oliver J Gruss
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Universität Heidelberg, D-69120 Heidelberg, Germany
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38
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Guiro J, O'Reilly D. Insights into the U1 small nuclear ribonucleoprotein complex superfamily. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:79-92. [DOI: 10.1002/wrna.1257] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/17/2014] [Accepted: 07/14/2014] [Indexed: 12/12/2022]
Affiliation(s)
- J Guiro
- Institute of Biosciences; University of Sao Paulo; Sao Paulo Brazil
| | - D O'Reilly
- Sir William Dunn School of Pathology; Oxford United Kingdom
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39
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Stejskalová E, Staněk D. The splicing factor U1-70K interacts with the SMN complex and is required for nuclear gem integrity. J Cell Sci 2014; 127:3909-15. [PMID: 25052091 DOI: 10.1242/jcs.155838] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The nuclear SMN complex localizes to specific structures called nuclear gems. The loss of gems is a cellular marker for several neurodegenerative diseases. Here, we identify that the U1-snRNP-specific protein U1-70K localizes to nuclear gems, and we show that U1-70K is necessary for gem integrity. Furthermore, we show that the interaction between U1-70K and the SMN complex is RNA independent, and we map the SMN complex binding site to the unstructured N-terminal tail of U1-70K. Consistent with these results, the expression of the U1-70K N-terminal tail rescues gem formation. These findings show that U1-70K is an SMN-complex-associating protein, and they suggest a new function for U1-70K in the formation of nuclear gems.
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Affiliation(s)
- Eva Stejskalová
- Department of RNA Biology, Institute of Molecular Genetics AS CR, 142 20 Prague, Czech Republic Faculty of Science, Charles University in Prague, 128 43 Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics AS CR, 142 20 Prague, Czech Republic
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40
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Preußer C, Rossbach O, Hung LH, Li D, Bindereif A. Genome-wide RNA-binding analysis of the trypanosome U1 snRNP proteins U1C and U1-70K reveals cis/trans-spliceosomal network. Nucleic Acids Res 2014; 42:6603-15. [PMID: 24748659 PMCID: PMC4041458 DOI: 10.1093/nar/gku286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Trans-splicing in trypanosomes adds a 39-nucleotide mini-exon from the spliced leader (SL) RNA to the 5′ end of each protein-coding sequence. On the other hand, cis-splicing of the few intron-containing genes requires the U1 small nuclear ribonucleoprotein (snRNP) particle. To search for potential new functions of the U1 snRNP in Trypanosoma brucei, we applied genome-wide individual-nucleotide resolution crosslinking-immunoprecipitation (iCLIP), focusing on the U1 snRNP-specific proteins U1C and U1-70K. Surprisingly, U1C and U1-70K interact not only with the U1, but also with U6 and SL RNAs. In addition, mapping of crosslinks to the cis-spliced PAP [poly(A) polymerase] pre-mRNA indicate an active role of these proteins in 5′ splice site recognition. In sum, our results demonstrate that the iCLIP approach provides insight into stable and transient RNA–protein contacts within the spliceosomal network. We propose that the U1 snRNP may represent an evolutionary link between the cis- and trans-splicing machineries, playing a dual role in 5′ splice site recognition on the trans-spliceosomal SL RNP as well as on pre-mRNA cis-introns.
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Affiliation(s)
- Christian Preußer
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Oliver Rossbach
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Lee-Hsueh Hung
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Dan Li
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Albrecht Bindereif
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
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41
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Husedzinovic A, Oppermann F, Draeger-Meurer S, Chari A, Fischer U, Daub H, Gruss OJ. Phosphoregulation of the human SMN complex. Eur J Cell Biol 2014; 93:106-17. [PMID: 24602413 DOI: 10.1016/j.ejcb.2014.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 01/22/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022] Open
Abstract
The survival motor neuron (SMN) complex is a macromolecular machine comprising 9 core proteins: SMN, Gemins2-8 and unrip in vertebrates. It performs tasks in RNA metabolism including the cytoplasmic assembly of spliceosomal small nuclear ribonucleoprotein particles (snRNPs). The SMN complex also localizes to the nucleus, where it accumulates in Cajal Bodies (CB) and may function in transcription and/or pre-mRNA splicing. The SMN complex is subject to extensive phosphorylation. Detailed understanding of SMN complex regulation necessitates a comprehensive analysis of these post-translational modifications. Here, we report on the first comprehensive phosphoproteome analysis of the intact human SMN complex, which identify 48 serine/threonine phosphosites in the complex. We find that 7 out of 9 SMN components of the intact complex are phosphoproteins and confidently place 29 phosphorylation sites, 12 of them in SMN itself. By the generation of multi non-phosphorylatable or phosphomimetic variants of SMN, respectively, we address to which extent phosphorylation regulates SMN complex function and localization. Both phosphomimetic and non-phosphorylatable variants assemble into intact SMN complexes and can compensate the loss of endogenous SMN in snRNP assembly at least to some extent. However, they partially or completely fail to target to nuclear Cajal bodies. Moreover, using a mutant of SMN, which cannot be phosphorylated on previously reported tyrosine residues, we provide first evidence that this PTM regulates SMN localization and nuclear accumulation. Our data suggest complex regulatory cues mediated by phosphorylation of serine/threonine and tyrosine residues, which control the subcellular localization of the SMN complex and its accumulation in nuclear CB.
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Affiliation(s)
- Alma Husedzinovic
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
| | - Felix Oppermann
- Evotec AG, Am Klopferspitz 19a, D-82152 Martinsried, Germany
| | - Stefanie Draeger-Meurer
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Ashwin Chari
- Theodor Boveri Institute, Biocenter of the University of Wuerzburg, D-97074 Wuerzburg, Germany
| | - Utz Fischer
- Theodor Boveri Institute, Biocenter of the University of Wuerzburg, D-97074 Wuerzburg, Germany
| | - Henrik Daub
- Evotec AG, Am Klopferspitz 19a, D-82152 Martinsried, Germany
| | - Oliver J Gruss
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
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42
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Workman E, Veith A, Battle DJ. U1A regulates 3' processing of the survival motor neuron mRNA. J Biol Chem 2014; 289:3703-12. [PMID: 24362020 PMCID: PMC3916568 DOI: 10.1074/jbc.m113.538264] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 12/16/2013] [Indexed: 12/12/2022] Open
Abstract
Insufficient expression of the survival motor neuron (SMN) protein causes spinal muscular atrophy, a neurodegenerative disease characterized by loss of motor neurons. Despite the importance of maintaining adequate SMN levels, little is known about factors that control SMN expression, particularly 3' end processing of the SMN pre-mRNA. In this study, we identify the U1A protein as a key regulator of SMN expression. U1A, a component of the U1 snRNP, is known to inhibit polyadenylation upon direct binding to mRNA. We show that U1A binds directly and with high affinity and specificity to the SMN 3'-UTR adjacent to the polyadenylation site, independent of the U1 snRNP (U1 small nuclear ribonucleoprotein). Binding of U1A inhibits polyadenylation of the SMN pre-mRNA by specifically inhibiting 3' cleavage by the cleavage and polyadenylation specificity factor. Expression of U1A in excess of U1 snRNA causes inhibition of SMN polyadenylation and decreases SMN protein levels. This work reveals a new mechanism for regulating SMN levels and provides new insight into the roles of U1A in 3' processing of mRNAs.
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Affiliation(s)
- Eileen Workman
- From the Departments of Molecular and Cellular Biochemistry and
| | - Alex Veith
- From the Departments of Molecular and Cellular Biochemistry and
| | - Daniel J. Battle
- From the Departments of Molecular and Cellular Biochemistry and
- Neurology, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210
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43
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Hossain M, Sharma S, Korde R, Kanodia S, Chugh M, Rawat K, Malhotra P. Organization of Plasmodium falciparum spliceosomal core complex and role of arginine methylation in its assembly. Malar J 2013; 12:333. [PMID: 24047207 PMCID: PMC3848767 DOI: 10.1186/1475-2875-12-333] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/13/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Splicing and alternate splicing are the two key biological processes that result in the generation of diverse transcript and protein isoforms in Plasmodium falciparum as well as in other eukaryotic organisms. Not much is known about the organization of splicing machinery and mechanisms in human malaria parasite. Present study reports the organization and assembly of Plasmodium spliceosome Sm core complex. METHODS Presence of all the seven Plasmodium Sm-like proteins in the intra-erythrocytic stages was assessed based on the protein(s) expression analysis using immuno-localization and western blotting. Localization/co-localization studies were performed by immunofluorescence analysis on thin parasite smear using laser scanning confocal microscope. Interaction studies were carried out using yeast two-hybrid analysis and validated by in vitro pull-down assays. PfPRMT5 (arginine methyl transferase) and PfSmD1 interaction analysis was performed by pull-down assays and the interacting proteins were identified by MALDI-TOF spectrometry. RESULTS PfSm proteins are expressed at asexual blood stages of the parasite and show nucleo-cytoplasmic localization. Protein-protein interaction studies showed that PfSm proteins form a heptameric complex, typical of spliceosome core complex as shown in humans. Interaction of PfSMN (survival of motor neuron, tudor domain containing protein) or PfTu-TSN (Tudor domain of Tudor Staphylococcal nuclease) with PfSmD1 proteins was found to be methylation dependent. Co-localization by immunofluorescence and co-immunoprecipitation studies suggested an association between PfPRMT5 and PfSmD1, indicating the role of arginine methylation in assembly of Plasmodium spliceosome complex. CONCLUSIONS Plasmodium Sm-like proteins form a heptameric ring-like structure, although the arrangement of PfSm proteins slightly differs from human splicing machinery. The data shows the interaction of PfSMN with PfSmD1 and this interaction is found to be methylation dependent. PfPRMT5 probably exists as a part of methylosome complex that may function in the cytoplasmic assembly of Sm proteins at asexual blood stages of P. falciparum.
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Affiliation(s)
- Manzar Hossain
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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44
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Zhang L, Li X, Zhao R. Structural analyses of the pre-mRNA splicing machinery. Protein Sci 2013; 22:677-92. [PMID: 23592432 DOI: 10.1002/pro.2266] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/03/2023]
Abstract
Pre-mRNA splicing is a critical event in the gene expression pathway of all eukaryotes. The splicing reaction is catalyzed by the spliceosome, a huge protein-RNA complex that contains five snRNAs and hundreds of different protein factors. Understanding the structure of this large molecular machinery is critical for understanding its function. Although the highly dynamic nature of the spliceosome, in both composition and conformation, posed daunting challenges to structural studies, there has been significant recent progress on structural analyses of the splicing machinery, using electron microscopy, crystallography, and nuclear magnetic resonance. This review discusses key recent findings in the structural analyses of the spliceosome and its components and how these findings advance our understanding of the function of the splicing machinery.
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Affiliation(s)
- Lingdi Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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45
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Mura C, Randolph PS, Patterson J, Cozen AE. Archaeal and eukaryotic homologs of Hfq: A structural and evolutionary perspective on Sm function. RNA Biol 2013; 10:636-51. [PMID: 23579284 PMCID: PMC3710371 DOI: 10.4161/rna.24538] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hfq and other Sm proteins are central in RNA metabolism, forming an evolutionarily conserved family that plays key roles in RNA processing in organisms ranging from archaea to bacteria to human. Sm-based cellular pathways vary in scope from eukaryotic mRNA splicing to bacterial quorum sensing, with at least one step in each of these pathways being mediated by an RNA-associated molecular assembly built upon Sm proteins. Though the first structures of Sm assemblies were from archaeal systems, the functions of Sm-like archaeal proteins (SmAPs) remain murky. Our ignorance about SmAP biology, particularly vis-à-vis the eukaryotic and bacterial Sm homologs, can be partly reduced by leveraging the homology between these lineages to make phylogenetic inferences about Sm functions in archaea. Nevertheless, whether SmAPs are more eukaryotic (RNP scaffold) or bacterial (RNA chaperone) in character remains unclear. Thus, the archaeal domain of life is a missing link, and an opportunity, in Sm-based RNA biology.
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Affiliation(s)
- Cameron Mura
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
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46
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Rajagopala SV, Sikorski P, Caufield JH, Tovchigrechko A, Uetz P. Studying protein complexes by the yeast two-hybrid system. Methods 2012; 58:392-9. [PMID: 22841565 DOI: 10.1016/j.ymeth.2012.07.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/10/2012] [Accepted: 07/12/2012] [Indexed: 01/13/2023] Open
Abstract
Protein complexes are typically analyzed by affinity purification and subsequent mass spectrometric analysis. However, in most cases the structure and topology of the complexes remains elusive from such studies. Here we investigate how the yeast two-hybrid system can be used to analyze direct interactions among proteins in a complex. First we tested all pairwise interactions among the seven proteins of Escherichia coli DNA polymerase III as well as an uncharacterized complex that includes MntR and PerR. Four and seven interactions were identified in these two complexes, respectively. In addition, we review Y2H data for three other complexes of known structure which serve as "gold-standards", namely Varicella Zoster Virus (VZV) ribonucleotide reductase (RNR), the yeast proteasome, and bacteriophage lambda. Finally, we review an Y2H analysis of the human spliceosome which may serve as an example for a dynamic mega-complex.
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47
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Frankenstein Z, Sperling J, Sperling R, Eisenstein M. A unique spatial arrangement of the snRNPs within the native spliceosome emerges from in silico studies. Structure 2012; 20:1097-106. [PMID: 22578543 DOI: 10.1016/j.str.2012.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 02/25/2012] [Accepted: 03/26/2012] [Indexed: 02/05/2023]
Abstract
The spliceosome is a mega-Dalton ribonucleoprotein (RNP) assembly that processes primary RNA transcripts, producing functional mRNA. The electron microscopy structures of the native spliceosome and of several spliceosomal subcomplexes are available; however, the spatial arrangement of the latter within the native spliceosome is not known. We designed a computational procedure to efficiently fit thousands of conformers into the spliceosome envelope. Despite the low resolution limitations, we obtained only one model that complies with the available biochemical data. Our model localizes the five small nuclear RNPs (snRNPs) mostly within the large subunit of the native spliceosome, requiring only minor conformation changes. The remaining free volume presumably accommodates additional spliceosomal components. The constituents of the active core of the spliceosome are juxtaposed, forming a continuous surface deep within the large spliceosomal cavity, which provides a sheltered environment for the splicing reaction.
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Affiliation(s)
- Ziv Frankenstein
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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48
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Telesco SE, Radhakrishnan R. Structural systems biology and multiscale signaling models. Ann Biomed Eng 2012; 40:2295-306. [PMID: 22539148 DOI: 10.1007/s10439-012-0576-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 04/11/2012] [Indexed: 12/13/2022]
Abstract
We review current advances in experimental as well as computational modeling and simulation approaches to structural systems biology, whose overall aim is to build quantitative models of signaling networks while retaining the crucial elements of molecular specificity. We briefly discuss the current and emerging experimental and computational methods, particularly focusing on hybrid and multiscale methods, and highlight several applications in cell signaling with quantitative and predictive capabilities. The scope of such models range from delineating protein-protein interactions to describing clinical implications.
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Affiliation(s)
- Shannon E Telesco
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
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49
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van der Feltz C, Anthony K, Brilot A, Pomeranz Krummel DA. Architecture of the Spliceosome. Biochemistry 2012; 51:3321-33. [DOI: 10.1021/bi201215r] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Clarisse van der Feltz
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, Massachusetts
02454, United States
| | - Kelsey Anthony
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, Massachusetts
02454, United States
| | - Axel Brilot
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, Massachusetts
02454, United States
| | - Daniel A. Pomeranz Krummel
- Department of Biochemistry, Brandeis University, 415 South Street, Waltham, Massachusetts
02454, United States
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50
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Gao X, Zhao X, Zhu Y, He J, Shao J, Su C, Zhang Y, Zhang W, Saarikettu J, Silvennoinen O, Yao Z, Yang J. Tudor staphylococcal nuclease (Tudor-SN) participates in small ribonucleoprotein (snRNP) assembly via interacting with symmetrically dimethylated Sm proteins. J Biol Chem 2012; 287:18130-41. [PMID: 22493508 DOI: 10.1074/jbc.m111.311852] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Human Tudor staphylococcal nuclease (Tudor-SN) is composed of four tandem repeats of staphylococcal nuclease (SN)-like domains, followed by a tudor and SN-like domain (TSN) consisting of a central tudor flanked by two partial SN-like sequences. The crystal structure of the tudor domain displays a conserved aromatic cage, which is predicted to hook methyl groups. Here, we demonstrated that the TSN domain of Tudor-SN binds to symmetrically dimethylarginine (sDMA)-modified SmB/B' and SmD1/D3 core proteins of the spliceosome. We demonstrated that this interaction ability is reduced by the methyltransferase inhibitor 5-deoxy-5-(methylthio)adenosine. Mutagenesis experiments indicated that the conserved amino acids (Phe-715, Tyr-721, Tyr-738, and Tyr-741) in the methyl-binding cage of the TSN domain are required for Tudor-SN-SmB interaction. Furthermore, depletion of Tudor-SN affects the association of Sm protein with snRNAs and, as a result, inhibits the assembly of uridine-rich small ribonucleoprotein mediated by the Sm core complex in vivo. Our results reveal the molecular basis for the involvement of Tudor-SN in regulating small nuclear ribonucleoprotein biogenesis, which provides novel insight related to the biological activity of Tudor-SN.
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Affiliation(s)
- Xingjie Gao
- Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 30070, China
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