1
|
Liang Q, Zhang Z, Ding B, Shao Y, Ding Q, Dai J, Hu X, Wu W, Wang X. A noncanonical splicing variant c.875-5 T > G in von Willebrand factor causes in-frame exon skipping and type 2A von Willebrand disease. Thromb Res 2024; 236:51-60. [PMID: 38387303 DOI: 10.1016/j.thromres.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/16/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024]
Abstract
INTRODUCTION A novel variant involving noncanonical splicing acceptor site (c.875-5 T > G) in propeptide coding region of von Willebrand factor (VWF) was identified in a patient with type 2A von Willebrand disease (VWD), who co-inherited with a null variant (p.Tyr271*) and presented characteristic discrepancy of plasma level of VWF antigen and activity, and a selective reduction of both intermediate-molecular-weight (IMWMs) and high-molecular-weight VWF multimers (HMWMs). MATERIALS AND METHODS VWF mRNA transcripts obtained from peripheral leukocytes and platelets of the patients were investigated to analyze the consequence of c.875-5 T > G on splicing. The impact of the variant on expression and multimer assembly was further analyzed by in vitro expression studies in AtT-20 cells. The intracellular processing of VWF mutant and the Weibel-Palade bodies (WPBs) formation was evaluated by immunofluorescence staining and electron microscopy. RESULTS The mRNA transcript analysis revealed that c.875-5 T > G variant led to exon 8 skipping and an in-frame deletion of 41 amino acids in the D1 domain of VWF (p.Ser292_Glu333delinsLys), yielding a truncated propeptide. Consistent with the patient's laboratory manifestations, the AtT-20 cells transfected with mutant secreted less VWF, with the VWF antigen level in conditioned medium 47 % of wild-type. A slight retention in the endoplasmic reticulum was observed for the mutant. Almost complete loss of IMWMs and HMWMs in the medium and impaired WPBs formation in the cell, indicating truncated VWF propeptide lost its chaperon-like function for VWF multimerization and tubular storage. CONCLUSIONS The VWF splicing site variant (c.875-5 T > G) causes propeptide truncation, severely compromising VWF multimer assembly and tubular storage.
Collapse
Affiliation(s)
- Qian Liang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ziqi Zhang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, China
| | - Biying Ding
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yanyan Shao
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jing Dai
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiaobo Hu
- Department of Molecular Biology, Shanghai Center for Clinical Laboratory, Shanghai, China.
| | - Wenman Wu
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Xuefeng Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| |
Collapse
|
2
|
Liu K, Dai W, Ju J, Li W, Chen Q, Li J, Liu H. Depletion of TIAR impairs embryogenesis via inhibiting zygote genome transcribe. Reprod Domest Anim 2023; 58:1456-1467. [PMID: 37667420 DOI: 10.1111/rda.14461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 09/06/2023]
Abstract
T cell intracellular antigen 1 related protein (TIAR), an RNA-binding protein (RBP), regulates pre-messenger RNA (pre-mRNA) alternative splicing, has been suggested to affect the maturation of primordial germ cells and early mouse embryo development. However, the underlying mechanism remains elusive. In this study, we revealed that TIAR was primarily located in the nucleus at the 2-cell stage embryo, accompanied by highly active transcription. Using immunofluorescence staining and western blotting, we first described the localization and expression level of TIAR during the whole period of oocyte matured and embryogenesis. Knocked down of TIAR could significantly inhibit transcribed and blocked the early mouse embryo development. Combined with RNAP II inhibitor and pre-RNA splicing inhibitor treatment, we further supposed that TIAR might affect transcription at 2-cell via regulating pre-mRNA splicing, and then regulate early mouse embryo development. Collectively, our results provided a novel and potential understanding of TIAR in embryogenesis, suggesting TIAR is required for transcription and embryonic development.
Collapse
Affiliation(s)
- Ke Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Weilong Dai
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Jiaqian Ju
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Weijian Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Qianqian Chen
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Juan Li
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Honglin Liu
- Department of Animal Genetics, Breeding and Reproduction, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| |
Collapse
|
3
|
Zhang T, Zheng H, Lu D, Guan G, Li D, Zhang J, Liu S, Zhao J, Guo JT, Lu F, Chen X. RNA binding protein TIAR modulates HBV replication by tipping the balance of pgRNA translation. Signal Transduct Target Ther 2023; 8:346. [PMID: 37699883 PMCID: PMC10497612 DOI: 10.1038/s41392-023-01573-7] [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: 01/30/2023] [Revised: 06/20/2023] [Accepted: 07/23/2023] [Indexed: 09/14/2023] Open
Abstract
The pregenomic RNA (pgRNA) of hepatitis B virus (HBV) serves not only as a bicistronic message RNA to translate core protein (Cp) and DNA polymerase (Pol), but also as the template for reverse transcriptional replication of viral DNA upon packaging into nucleocapsid. Although it is well known that pgRNA translates much more Cp than Pol, the molecular mechanism underlying the regulation of Cp and Pol translation efficiency from pgRNA remains elusive. In this study, we systematically profiled HBV nucleocapsid- and pgRNA-associated cellular proteins by proteomic analysis and identified TIA-1-related protein (TIAR) as a novel cellular protein that binds pgRNA and promotes HBV DNA replication. Interestingly, loss- and gain-of-function genetic analyses showed that manipulation of TIAR expression did not alter the levels of HBV transcripts nor the secretion of HBsAg and HBeAg in human hepatoma cells supporting HBV replication. However, Ribo-seq and PRM-based mass spectrometry analyses demonstrated that TIAR increased the translation of Pol but decreased the translation of Cp from pgRNA. RNA immunoprecipitation (RIP) and pulldown assays further revealed that TIAR directly binds pgRNA at the 5' stem-loop (ε). Moreover, HBV replication or Cp expression induced the increased expression and redistribution of TIAR from the nucleus to the cytoplasm of hepatocytes. Our results thus imply that TIAR is a novel cellular factor that regulates HBV replication by binding to the 5' ε structure of pgRNA to tip the balance of Cp and Pol translation. Through induction of TIAR translocation from the nucleus to the cytoplasm, Cp indirectly regulates the Pol translation and balances Cp and Pol expression levels in infected hepatocytes to ensure efficient viral replication.
Collapse
Affiliation(s)
- Ting Zhang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Huiling Zheng
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Danjuan Lu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Guiwen Guan
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Deyao Li
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jing Zhang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Shuhong Liu
- Department of Pathology and Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100039, China
| | - Jingmin Zhao
- Department of Pathology and Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100039, China
| | - Ju-Tao Guo
- Department of Experimental Therapeutics, Baruch S. Blumberg Institute, Doylestown, PA, 18902, USA.
| | - Fengmin Lu
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
- Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases, Peking University Hepatology Institute, Peking University People's Hospital, Beijing, 100044, China.
| | - Xiangmei Chen
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
| |
Collapse
|
4
|
Huang W, Zhang L, Zhu Y, Chen J, Zhu Y, Lin F, Chen X, Huang J. A genetic screen in Arabidopsis reveals the identical roles for RBP45d and PRP39a in 5' cryptic splice site selection. FRONTIERS IN PLANT SCIENCE 2022; 13:1086506. [PMID: 36618610 PMCID: PMC9813592 DOI: 10.3389/fpls.2022.1086506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Cryptic splice sites in eukaryotic genome are generally dormant unless activated by mutation of authentic splice sites or related splicing factors. How cryptic splice sites are used remains unclear in plants. Here, we identified two cryptic splicing regulators, RBP45d and PRP39a that are homologs of yeast U1 auxiliary protein Nam8 and Prp39, respectively, via genetic screening for suppressors of the virescent sot5 mutant, which results from a point mutation at the 5' splice site (5' ss) of SOT5 intron 7. Loss-of-function mutations in RBP45d and PRP39a significantly increase the level of a cryptically spliced variant that encodes a mutated but functional sot5 protein, rescuing sot5 to the WT phenotype. We furtherly demonstrated that RBP45d and PRP39a interact with each other and also with the U1C, a core subunit of U1 snRNP. We found that RBP45d directly binds to the uridine (U)-rich RNA sequence downstream the 5' ss of SOT5 intron 7. However, other RBP45/47 members do not function redundantly with RBP45d, at least in regulation of cryptic splicing. Taken together, RBP45d promotes U1 snRNP to recognize the specific 5' ss via binding to intronic U-rich elements in plants.
Collapse
Affiliation(s)
- Weihua Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Liqun Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yajuan Zhu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jingli Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yawen Zhu
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Fengru Lin
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Xiaomei Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| |
Collapse
|
5
|
Osma-Garcia IC, Capitan-Sobrino D, Mouysset M, Aubert Y, Maloudi O, Turner M, Diaz-Muñoz MD. The splicing regulators TIA1 and TIAL1 are required for the expression of the DNA damage repair machinery during B cell lymphopoiesis. Cell Rep 2022; 41:111869. [PMID: 36543128 PMCID: PMC9794549 DOI: 10.1016/j.celrep.2022.111869] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 10/01/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
B cell lymphopoiesis requires dynamic modulation of the B cell transcriptome for timely coordination of somatic mutagenesis and DNA repair in progenitor B (pro-B) cells. Here, we show that, in pro-B cells, the RNA-binding proteins T cell intracellular antigen 1 (TIA1) and TIA1-like protein (TIAL1) act redundantly to enable developmental progression. They are global splicing regulators that control the expression of hundreds of mRNAs, including those involved in DNA damage repair. Mechanistically, TIA1 and TIAL1 bind to 5' splice sites for exon definition, splicing, and expression of DNA damage sensors, such as Chek2 and Rif1. In their absence, pro-B cells show exacerbated DNA damage, altered P53 expression, and increased cell death. Our study uncovers the importance of tight regulation of RNA splicing by TIA1 and TIAL1 for the expression of integrative transcriptional programs that control DNA damage sensing and repair during B cell development.
Collapse
Affiliation(s)
- Ines C. Osma-Garcia
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France
| | - Dunja Capitan-Sobrino
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France
| | - Mailys Mouysset
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France
| | - Yann Aubert
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France
| | - Orlane Maloudi
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France
| | - Martin Turner
- Immunology Program, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Manuel D. Diaz-Muñoz
- Toulouse Institute for Infectious and Inflammatory Diseases (INFINITy), Inserm UMR1291, CNRS UMR5051, University Paul Sabatier, CHU Purpan, Toulouse 31024, France,Corresponding author
| |
Collapse
|
6
|
Velasco BR, Izquierdo JM. T-Cell Intracellular Antigen 1-Like Protein in Physiology and Pathology. Int J Mol Sci 2022; 23:ijms23147836. [PMID: 35887183 PMCID: PMC9318959 DOI: 10.3390/ijms23147836] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 11/16/2022] Open
Abstract
T-cell intracellular antigen 1 (TIA1)-related/like (TIAR/TIAL1) protein is a multifunctional RNA-binding protein (RBP) involved in regulating many aspects of gene expression, independently or in combination with its paralog TIA1. TIAR was first described in 1992 by Paul Anderson’s lab in relation to the development of a cell death phenotype in immune system cells, as it possesses nucleolytic activity against cytotoxic lymphocyte target cells. Similar to TIA1, it is characterized by a subcellular nucleo-cytoplasmic localization and ubiquitous expression in the cells of different tissues of higher organisms. In this paper, we review the relevant structural and functional information available about TIAR from a triple perspective (molecular, cellular and pathophysiological), paying special attention to its expression and regulation in cellular events and processes linked to human pathophysiology.
Collapse
|
7
|
The Physiological Roles of the Exon Junction Complex in Development and Diseases. Cells 2022; 11:cells11071192. [PMID: 35406756 PMCID: PMC8997533 DOI: 10.3390/cells11071192] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/19/2022] [Accepted: 03/24/2022] [Indexed: 01/12/2023] Open
Abstract
The exon junction complex (EJC) becomes an increasingly important regulator of early gene expression in the central nervous system (CNS) and other tissues. The EJC is comprised of three core proteins: RNA-binding motif 8A (RBM8A), Mago homolog (MAGOH), eukaryotic initiation factor 4A3 (EIF4A3), and a peripheral EJC factor, metastatic lymph node 51 (MLN51), together with various auxiliary factors. The EJC is assembled specifically at exon-exon junctions on mRNAs, hence the name of the complex. The EJC regulates multiple levels of gene expression, from splicing to translation and mRNA degradation. The functional roles of the EJC have been established as crucial to the normal progress of embryonic and neurological development, with wide ranging implications on molecular, cellular, and organism level function. Dysfunction of the EJC has been implicated in multiple developmental and neurological diseases. In this review, we discuss recent progress on the EJC’s physiological roles.
Collapse
|
8
|
Malard F, Mackereth CD, Campagne S. Principles and correction of 5'-splice site selection. RNA Biol 2022; 19:943-960. [PMID: 35866748 PMCID: PMC9311317 DOI: 10.1080/15476286.2022.2100971] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/06/2022] [Indexed: 11/04/2022] Open
Abstract
In Eukarya, immature mRNA transcripts (pre-mRNA) often contain coding sequences, or exons, interleaved by non-coding sequences, or introns. Introns are removed upon splicing, and further regulation of the retained exons leads to alternatively spliced mRNA. The splicing reaction requires the stepwise assembly of the spliceosome, a macromolecular machine composed of small nuclear ribonucleoproteins (snRNPs). This review focuses on the early stage of spliceosome assembly, when U1 snRNP defines each intron 5'-splice site (5'ss) in the pre-mRNA. We first introduce the splicing reaction and the impact of alternative splicing on gene expression regulation. Thereafter, we extensively discuss splicing descriptors that influence the 5'ss selection by U1 snRNP, such as sequence determinants, and interactions mediated by U1-specific proteins or U1 small nuclear RNA (U1 snRNA). We also include examples of diseases that affect the 5'ss selection by U1 snRNP, and discuss recent therapeutic advances that manipulate U1 snRNP 5'ss selectivity with antisense oligonucleotides and small-molecule splicing switches.
Collapse
Affiliation(s)
- Florian Malard
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Cameron D Mackereth
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Sébastien Campagne
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| |
Collapse
|
9
|
Královičová J, Borovská I, Pengelly R, Lee E, Abaffy P, Šindelka R, Grutzner F, Vořechovský I. Restriction of an intron size en route to endothermy. Nucleic Acids Res 2021; 49:2460-2487. [PMID: 33550394 PMCID: PMC7969005 DOI: 10.1093/nar/gkab046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 11/15/2022] Open
Abstract
Ca2+-insensitive and -sensitive E1 subunits of the 2-oxoglutarate dehydrogenase complex (OGDHC) regulate tissue-specific NADH and ATP supply by mutually exclusive OGDH exons 4a and 4b. Here we show that their splicing is enforced by distant lariat branch points (dBPs) located near the 5' splice site of the intervening intron. dBPs restrict the intron length and prevent transposon insertions, which can introduce or eliminate dBP competitors. The size restriction was imposed by a single dominant dBP in anamniotes that expanded into a conserved constellation of four dBP adenines in amniotes. The amniote clusters exhibit taxon-specific usage of individual dBPs, reflecting accessibility of their extended motifs within a stable RNA hairpin rather than U2 snRNA:dBP base-pairing. The dBP expansion took place in early terrestrial species and was followed by a uridine enrichment of large downstream polypyrimidine tracts in mammals. The dBP-protected megatracts permit reciprocal regulation of exon 4a and 4b by uridine-binding proteins, including TIA-1/TIAR and PUF60, which promote U1 and U2 snRNP recruitment to the 5' splice site and BP, respectively, but do not significantly alter the relative dBP usage. We further show that codons for residues critically contributing to protein binding sites for Ca2+ and other divalent metals confer the exon inclusion order that mirrors the Irving-Williams affinity series, linking the evolution of auxiliary splicing motifs in exons to metallome constraints. Finally, we hypothesize that the dBP-driven selection for Ca2+-dependent ATP provision by E1 facilitated evolution of endothermy by optimizing the aerobic scope in target tissues.
Collapse
Affiliation(s)
- Jana Královičová
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Borovská
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Reuben Pengelly
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
| | - Eunice Lee
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Pavel Abaffy
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Radek Šindelka
- Czech Academy of Sciences, Institute of Biotechnology, 25250 Vestec, Czech Republic
| | - Frank Grutzner
- School of Biological Sciences, University of Adelaide, Adelaide 5005, SA, Australia
| | - Igor Vořechovský
- University of Southampton, Faculty of Medicine, HDH, Southampton SO16 6YD, UK
| |
Collapse
|
10
|
Vilys L, Peciuliene I, Jakubauskiene E, Zinkeviciute R, Makino Y, Kanopka A. U2AF - Hypoxia-induced fas alternative splicing regulator. Exp Cell Res 2020; 399:112444. [PMID: 33347855 DOI: 10.1016/j.yexcr.2020.112444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 12/01/2020] [Accepted: 12/15/2020] [Indexed: 01/21/2023]
Abstract
The splicing machinery heavily contributes to biological complexity and especially to the ability of cells to adapt to altered cellular conditions. Hypoxia also plays a key role in the pathophysiology of many disease states. Recent studies have revealed that tumorigenesis and hypoxia are involved in large-scale alterations in alternative pre-mRNA splicing. Fas pre-mRNA is alternatively spliced by excluding exon 6 to produce soluble Fas (sFas) protein that lacks a transmembrane domain and acts by inhibiting Fas mediated apoptosis. In the present study we show that U2AF is involved in hypoxia dependent anti-apoptotic Fas mRNA isoform formation. Our performed studies show that U2AF-RNA interaction is reduced in hypoxic cells, leading to reduction of Fas and increased sFas mRNAs formation. Efficient U2AF-RNA interactions of both subunits are important for Fas exon 6 inclusion into forming mRNA in normoxic and hypoxic cells.
Collapse
Affiliation(s)
- Laurynas Vilys
- Department of Immunology and Cell Biology, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Inga Peciuliene
- Department of Immunology and Cell Biology, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Egle Jakubauskiene
- Department of Immunology and Cell Biology, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Ruta Zinkeviciute
- Department of Eukaryote Gene Engineering, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Yuichi Makino
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical College, Asahikawa, Hokkaido, Japan
| | - Arvydas Kanopka
- Department of Immunology and Cell Biology, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
| |
Collapse
|
11
|
Guo C, Gao YY, Ju QQ, Zhang CX, Gong M, Li ZL. LINC00649 underexpression is an adverse prognostic marker in acute myeloid leukemia. BMC Cancer 2020; 20:841. [PMID: 32883226 PMCID: PMC7469387 DOI: 10.1186/s12885-020-07331-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/24/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Long noncoding RNAs (lncRNA) play a role in leukemogenesis, maintenance, development, and therapeutic resistance of AML. While few studies have focused on the prognostic significance of LINC00649 in AML, which we aim to investigate in this present study. METHODS We compared the expression level of LINC00649 between AML patients and healthy controls. The Kaplan-Meier curves of AML patients expressing high versus low level of LINC00649 was performed. The LINC00649 correlated genes/miRNAs/lncRNAs and methylation CpG sites were screened by Pearson correlation analysis with R (version 3.6.0), using TCGA-LAML database. The LINC00649 associated ceRNA network was established using lncBase 2.0 and miRWalk 2.0 online tools, combining results from correlation analysis. Finally, a prediction model was constructed using LASSO-Cox regression. RESULTS LINC00649 was underexpressed in bone marrow of AML group than that in healthy control group. The patients of LINC00649-low group have significantly inferior PFS and OS. A total of 154 mRNAs, 31 miRNAs, 28 lncRNAs and 1590 methylated CpG sites were identified to be significantly correlated with LINC00649. Furthermore, the network of ceRNA was established with 6 miRNAs and 122 mRNAs. The Lasso-Cox model fitted OS/PFS to novel prediction models, which integrated clinical factors, ELN risk stratification, mRNA/miRNA expression and methylation profiles. The analysis of time-dependent ROC for our model showed a superior AUC (AUC = 0.916 at 1 year, AUC = 0.916 at 3 years, and AUC = 0.891 at 5 years). CONCLUSIONS Low expression of LINC00649 is a potential unfavorable prognostic marker for AML patients, which requires the further validation. The analysis by LASSO-COX regression identified a novel comprehensive model with a superior diagnostic utility, which integrated clinical and genetic variables.
Collapse
Affiliation(s)
- Chao Guo
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China
| | - Ya-Yue Gao
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China
| | - Qian-Qian Ju
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China
| | - Chun-Xia Zhang
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China
| | - Ming Gong
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China
| | - Zhen-Ling Li
- Department of Hematology, China-Japan Friendship Hospital, Yinghua East Street, Beijing, China.
| |
Collapse
|
12
|
Wu KE, Parker KR, Fazal FM, Chang HY, Zou J. RNA-GPS predicts high-resolution RNA subcellular localization and highlights the role of splicing. RNA (NEW YORK, N.Y.) 2020; 26:851-865. [PMID: 32220894 PMCID: PMC7297119 DOI: 10.1261/rna.074161.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/19/2020] [Indexed: 06/10/2023]
Abstract
Subcellular localization is essential to RNA biogenesis, processing, and function across the gene expression life cycle. However, the specific nucleotide sequence motifs that direct RNA localization are incompletely understood. Fortunately, new sequencing technologies have provided transcriptome-wide atlases of RNA localization, creating an opportunity to leverage computational modeling. Here we present RNA-GPS, a new machine learning model that uses nucleotide-level features to predict RNA localization across eight different subcellular locations-the first to provide such a wide range of predictions. RNA-GPS's design enables high-throughput sequence ablation and feature importance analyses to probe the sequence motifs that drive localization prediction. We find localization informative motifs to be concentrated on 3'-UTRs and scattered along the coding sequence, and motifs related to splicing to be important drivers of predicted localization, even for cytotopic distinctions for membraneless bodies within the nucleus or for organelles within the cytoplasm. Overall, our results suggest transcript splicing is one of many elements influencing RNA subcellular localization.
Collapse
Affiliation(s)
- Kevin E Wu
- Department of Computer Science, Stanford University, Stanford, California 94305, USA
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, California 94305, USA
- Center for Personal and Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Kevin R Parker
- Center for Personal and Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Furqan M Fazal
- Center for Personal and Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Howard Y Chang
- Center for Personal and Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA
| | - James Zou
- Department of Computer Science, Stanford University, Stanford, California 94305, USA
- Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, California 94305, USA
| |
Collapse
|
13
|
Lafarga V, Sung HM, Haneke K, Roessig L, Pauleau AL, Bruer M, Rodriguez-Acebes S, Lopez-Contreras AJ, Gruss OJ, Erhardt S, Mendez J, Fernandez-Capetillo O, Stoecklin G. TIAR marks nuclear G2/M transition granules and restricts CDK1 activity under replication stress. EMBO Rep 2019; 20:e46224. [PMID: 30538118 PMCID: PMC6322364 DOI: 10.15252/embr.201846224] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/20/2022] Open
Abstract
The G2/M checkpoint coordinates DNA replication with mitosis and thereby prevents chromosome segregation in the presence of unreplicated or damaged DNA Here, we show that the RNA-binding protein TIAR is essential for the G2/M checkpoint and that TIAR accumulates in nuclear foci in late G2 and prophase in cells suffering from replication stress. These foci, which we named G2/M transition granules (GMGs), occur at low levels in normally cycling cells and are strongly induced by replication stress. In addition to replication stress response proteins, GMGs contain factors involved in RNA metabolism as well as CDK1. Depletion of TIAR accelerates mitotic entry and leads to chromosomal instability in response to replication stress, in a manner that can be alleviated by the concomitant depletion of Cdc25B or inhibition of CDK1. Since TIAR retains CDK1 in GMGs and attenuates CDK1 activity, we propose that the assembly of GMGs may represent a so far unrecognized mechanism that contributes to the activation of the G2/M checkpoint in mammalian cells.
Collapse
Affiliation(s)
- Vanesa Lafarga
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Hsu-Min Sung
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Division of Biochemistry, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Katharina Haneke
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Division of Biochemistry, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Lea Roessig
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Anne-Laure Pauleau
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Department of Cellular and Molecular Medicine, Center for Chromosome Stability and Center for Healthy Aging University of Copenhagen, Copenhagen, Denmark
| | - Marius Bruer
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Division of Biochemistry, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | - Andres J Lopez-Contreras
- Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- CellNetworks Excellence Cluster, Heidelberg University, Heidelberg, Germany
| | - Oliver J Gruss
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Sylvia Erhardt
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Department of Cellular and Molecular Medicine, Center for Chromosome Stability and Center for Healthy Aging University of Copenhagen, Copenhagen, Denmark
| | - Juan Mendez
- Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Oscar Fernandez-Capetillo
- Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Georg Stoecklin
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Division of Biochemistry, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| |
Collapse
|
14
|
Carrascoso I, Alcalde J, Tabas-Madrid D, Oliveros JC, Izquierdo JM. Transcriptome-wide analysis links the short-term expression of the b isoforms of TIA proteins to protective proteostasis-mediated cell quiescence response. PLoS One 2018; 13:e0208526. [PMID: 30533021 PMCID: PMC6289441 DOI: 10.1371/journal.pone.0208526] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/19/2018] [Indexed: 12/20/2022] Open
Abstract
Control of gene expression depends on genetics and environmental factors. The T-cell intracellular antigens T-cell intracellular antigen 1 (TIA1), TIA1-like/related protein (TIAL1/TIAR) and human antigen R (HuR/ELAVL1) are RNA-binding proteins that play crucial roles in regulating gene expression in both situations. This study used massive sequencing analysis to uncover molecular and functional mechanisms resulting from the short-time expression of the b isoforms of TIA1 and TIAR, and of HuR in HEK293 cells. Our gene profiling analysis identified several hundred differentially expressed genes (DEGs) and tens of alternative splicing events associated with TIA1b, TIARb and HuR overexpression. Gene ontology analysis revealed that the controlled expression of these proteins strongly influences the patterns of DEGs and RNA variants preferentially associated with development, reproduction, cell cycle, metabolism, autophagy and apoptosis. Mechanistically, TIA1b and TIARb isoforms display both common and differential effects on the regulation of gene expression, involving systematic perturbations of cell biosynthetic machineries (splicing and translation). The transcriptome outputs were validated using functional assays of the targeted cellular processes as well as expression analysis for selected genes. Collectively, our observations suggest that early TIA1b and TIARb expression operates to connect the regulatory crossroads to protective proteostasis responses associated with a survival quiescence phenotype.
Collapse
Affiliation(s)
- Isabel Carrascoso
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/ Nicolás Cabrera, Madrid, Spain
| | - José Alcalde
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/ Nicolás Cabrera, Madrid, Spain
| | - Daniel Tabas-Madrid
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, C/ Darwin, Madrid, Spain
| | - Juan Carlos Oliveros
- Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, C/ Darwin, Madrid, Spain
| | - José M. Izquierdo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/ Nicolás Cabrera, Madrid, Spain
- * E-mail:
| |
Collapse
|
15
|
Micheletti R, Plaisance I, Abraham BJ, Sarre A, Ting CC, Alexanian M, Maric D, Maison D, Nemir M, Young RA, Schroen B, González A, Ounzain S, Pedrazzini T. The long noncoding RNA Wisper controls cardiac fibrosis and remodeling. Sci Transl Med 2018. [PMID: 28637928 DOI: 10.1126/scitranslmed.aai9118] [Citation(s) in RCA: 214] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Long noncoding RNAs (lncRNAs) are emerging as powerful regulators of cardiac development and disease. However, our understanding of the importance of these molecules in cardiac fibrosis is limited. Using an integrated genomic screen, we identified Wisper (Wisp2 super-enhancer-associated RNA) as a cardiac fibroblast-enriched lncRNA that regulates cardiac fibrosis after injury. Wisper expression was correlated with cardiac fibrosis both in a murine model of myocardial infarction (MI) and in heart tissue from human patients suffering from aortic stenosis. Loss-of-function approaches in vitro using modified antisense oligonucleotides (ASOs) demonstrated that Wisper is a specific regulator of cardiac fibroblast proliferation, migration, and survival. Accordingly, ASO-mediated silencing of Wisper in vivo attenuated MI-induced fibrosis and cardiac dysfunction. Functionally, Wisper regulates cardiac fibroblast gene expression programs critical for cell identity, extracellular matrix deposition, proliferation, and survival. In addition, its association with TIA1-related protein allows it to control the expression of a profibrotic form of lysyl hydroxylase 2, implicated in collagen cross-linking and stabilization of the matrix. Together, our findings identify Wisper as a cardiac fibroblast-enriched super-enhancer-associated lncRNA that represents an attractive therapeutic target to reduce the pathological development of cardiac fibrosis in response to MI and prevent adverse remodeling in the damaged heart.
Collapse
Affiliation(s)
- Rudi Micheletti
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Isabelle Plaisance
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Brian J Abraham
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Alexandre Sarre
- Cardiovascular Assessment Facility, University of Lausanne, Lausanne, Switzerland
| | - Ching-Chia Ting
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Michael Alexanian
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Daniel Maric
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Damien Maison
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Mohamed Nemir
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland
| | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Blanche Schroen
- Center for Heart Failure Research, Department of Cardiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands
| | - Arantxa González
- Centre for Applied Medical Research, University of Navarra, Pamplona, Spain.,National Institute of Health Carlos III, Madrid, Spain
| | - Samir Ounzain
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland.
| | - Thierry Pedrazzini
- Experimental Cardiology Unit, Department of Cardiovascular Medicine, University of Lausanne Medical School, Lausanne, Switzerland.
| |
Collapse
|
16
|
Sugai A, Kato T, Koyama A, Koike Y, Kasahara S, Konno T, Ishihara T, Onodera O. Robustness and Vulnerability of the Autoregulatory System That Maintains Nuclear TDP-43 Levels: A Trade-off Hypothesis for ALS Pathology Based on in Silico Data. Front Neurosci 2018; 12:28. [PMID: 29449800 PMCID: PMC5799296 DOI: 10.3389/fnins.2018.00028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/15/2018] [Indexed: 12/11/2022] Open
Abstract
Abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm and its disappearance from the nucleus are pathological features of amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) and are directly involved in the pathogenesis of these conditions. TDP-43 is an essential nuclear protein that readily aggregates in a concentration-dependent manner. Therefore, cells must strictly maintain an appropriate amount of nuclear TDP-43. In one relevant maintenance mechanism, TDP-43 binds to its pre-mRNA and promotes alternative splicing, resulting in mRNA degradation via nonsense-mediated mRNA decay. The level of nuclear TDP-43 is tightly regulated by these mechanisms, which control the amount of mRNA that may be translated. Based on the results of previous experiments, we developed an in silico model that mimics the intracellular dynamics of TDP-43 and examined TDP-43 metabolism under various conditions. We discovered an inherent trade-off in this mechanism between transcriptional redundancy, which maintains the robustness of TDP-43 metabolism, and vulnerability to specific interfering factors. These factors include an increased tendency of TDP-43 to aggregate, impaired nuclear-cytoplasmic TDP-43 transport, and a decreased efficiency of degrading abnormal proteins, all of which are functional abnormalities related to the gene that causes familial ALS/FTD. When these conditions continue at a certain intensity, the vulnerability of the autoregulatory machinery becomes apparent over time, and transcriptional redundancy enters a vicious cycle that ultimately results in TDP-43 pathology. The results obtained using this in silico model reveal the difference in TDP-43 metabolism between normal and disease states. Furthermore, using this model, we simulated the effect of a decrease in TDP-43 transcription and found that this decrease improved TDP-43 pathology and suppressed the abnormal propagation of TDP-43. Therefore, we propose a potential therapeutic strategy to suppress transcriptional redundancy, which is the driving force of the pathological condition caused by the specific factors described above, in patients with ALS presenting with TDP-43 pathology. An ALS animal model exhibiting TDP-43 pathology without overexpression of exogenous TDP-43 should be developed to investigate the effect of alleviating the transcriptional redundancy of TARDBP.
Collapse
Affiliation(s)
- Akihiro Sugai
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata, Japan
| | - Taisuke Kato
- Department of System Pathology for Neurological Disorders, Brain Science Branch, Center for Bioresource-Based Research, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akihide Koyama
- Division of Legal Medicine, Graduate School of Medicine and Dental Science, Niigata University, Niigata, Japan
| | - Yuka Koike
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata, Japan
| | - Sou Kasahara
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takuya Konno
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata, Japan
| | - Tomohiko Ishihara
- Department of Molecular Neuroscience, Resource Branch for Brain Disease Research, Center for Bioresource-based Research, Brain Research Institute, Niigata University, Niigata, Japan
| | - Osamu Onodera
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata, Japan
| |
Collapse
|
17
|
Ullah F, Hamilton M, Reddy ASN, Ben-Hur A. Exploring the relationship between intron retention and chromatin accessibility in plants. BMC Genomics 2018; 19:21. [PMID: 29304739 PMCID: PMC5756433 DOI: 10.1186/s12864-017-4393-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022] Open
Abstract
Background Intron retention (IR) is the most prevalent form of alternative splicing in plants. IR, like other forms of alternative splicing, has an important role in increasing gene product diversity and regulating transcript functionality. Splicing is known to occur co-transcriptionally and is influenced by the speed of transcription which in turn, is affected by chromatin structure. It follows that chromatin structure may have an important role in the regulation of splicing, and there is preliminary evidence in metazoans to suggest that this is indeed the case; however, nothing is known about the role of chromatin structure in regulating IR in plants. DNase I-seq is a useful experimental tool for genome-wide interrogation of chromatin accessibility, providing information on regions of chromatin with very high likelihood of cleavage by the enzyme DNase I, known as DNase I Hypersensitive Sites (DHSs). While it is well-established that promoter regions are highly accessible and are over-represented with DHSs, not much is known about DHSs in the bodies of genes, and their relationship to splicing in general, and IR in particular. Results In this study we use publicly available DNase I-seq data in arabidopsis and rice to investigate the relationship between IR and chromatin structure. We find that IR events are highly enriched in DHSs in both species. This implies that chromatin is more open in retained introns, which is consistent with a kinetic model of the process whereby higher speeds of transcription in those regions give less time for the spliceosomal machinery to recognize and splice out those introns co-transcriptionally. The more open chromatin in IR can also be the result of regulation mediated by DNA-binding proteins. To test this, we performed an exhaustive search for footprints left by DNA-binding proteins that are associated with IR. We identified several hundred short sequence elements that exhibit footprints in their DNase I-seq coverage, the telltale sign for binding events of a regulatory protein, protecting its binding site from cleavage by DNase I. A highly significant fraction of those sequence elements are conserved between arabidopsis and rice, a strong indication of their functional importance. Conclusions In this study we have established an association between IR and chromatin accessibility, and presented a mechanistic hypothesis that explains the observed association from the perspective of the co-transcriptional nature of splicing. Furthermore, we identified conserved sequence elements for DNA-binding proteins that affect splicing. Electronic supplementary material The online version of this article (10.1186/s12864-017-4393-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Fahad Ullah
- Computer Science Department, Colorado State University, 1873 Campus Delivery, Fort Collins, 80523, CO, USA
| | - Michael Hamilton
- Computer Science Department, Colorado State University, 1873 Campus Delivery, Fort Collins, 80523, CO, USA
| | - Anireddy S N Reddy
- Department of Biology, Colorado State University, 1878 Campus Delivery, Fort Collins, 80523, CO, USA
| | - Asa Ben-Hur
- Computer Science Department, Colorado State University, 1873 Campus Delivery, Fort Collins, 80523, CO, USA.
| |
Collapse
|
18
|
García-Mauriño SM, Rivero-Rodríguez F, Velázquez-Cruz A, Hernández-Vellisca M, Díaz-Quintana A, De la Rosa MA, Díaz-Moreno I. RNA Binding Protein Regulation and Cross-Talk in the Control of AU-rich mRNA Fate. Front Mol Biosci 2017; 4:71. [PMID: 29109951 PMCID: PMC5660096 DOI: 10.3389/fmolb.2017.00071] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/04/2017] [Indexed: 02/06/2023] Open
Abstract
mRNA metabolism is tightly orchestrated by highly-regulated RNA Binding Proteins (RBPs) that determine mRNA fate, thereby influencing multiple cellular functions across biological contexts. Here, we review the interplay between six well-known RBPs (TTP, AUF-1, KSRP, HuR, TIA-1, and TIAR) that recognize AU-rich elements (AREs) at the 3' untranslated regions of mRNAs, namely ARE-RBPs. Examples of the links between their cross-regulations and modulation of their targets are analyzed during mRNA processing, turnover, localization, and translational control. Furthermore, ARE recognition can be self-regulated by several factors that lead to the prevalence of one RBP over another. Consequently, we examine the factors that modulate the dynamics of those protein-RNA transient interactions to better understand the final consequences of the regulation mediated by ARE-RBPs. For instance, factors controlling the RBP isoforms, their conformational state or their post-translational modifications (PTMs) can strongly determine the fate of the protein-RNA complexes. Moreover, mRNA specific sequence and secondary structure or subtle environmental changes are also key determinants to take into account. To sum up, the whole understanding of such a fine tuned regulation is a challenge for future research and requires the integration of all the available structural and functional data by in vivo, in vitro and in silico approaches.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| |
Collapse
|
19
|
Dassi E. Handshakes and Fights: The Regulatory Interplay of RNA-Binding Proteins. Front Mol Biosci 2017; 4:67. [PMID: 29034245 PMCID: PMC5626838 DOI: 10.3389/fmolb.2017.00067] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022] Open
Abstract
What drives the flow of signals controlling the outcome of post-transcriptional regulation of gene expression? This regulatory layer, presiding to processes ranging from splicing to mRNA stability and localization, is a key determinant of protein levels and thus cell phenotypes. RNA-binding proteins (RBPs) form a remarkable army of post-transcriptional regulators, strong of more than 1,500 genes implementing this expression fine-tuning plan and implicated in both cell physiology and pathology. RBPs can bind and control a wide array of RNA targets. This sheer amount of interactions form complex regulatory networks (PTRNs) where the action of individual RBPs cannot be easily untangled from each other. While past studies have mostly focused on the action of individual RBPs on their targets, we are now observing an increasing amount of evidence describing the occurrence of interactions between RBPs, defining how common target RNAs are regulated. This suggests that the flow of signals in PTRNs is driven by the intertwined contribution of multiple RBPs, concurrently acting on each of their targets. Understanding how RBPs cooperate and compete is thus of paramount importance to chart the wiring of PTRNs and their impact on cell phenotypes. Here we review the current knowledge about patterns of RBP interaction and attempt at describing their general principles. We also discuss future directions which should be taken to reach a comprehensive understanding of this fundamental aspect of gene expression regulation.
Collapse
Affiliation(s)
- Erik Dassi
- Centre for Integrative Biology, University of Trento, Trento, Italy
| |
Collapse
|
20
|
Zhang J, Pearson JZ, Gorbet GE, Cölfen H, Germann MW, Brinton MA, Demeler B. Spectral and Hydrodynamic Analysis of West Nile Virus RNA-Protein Interactions by Multiwavelength Sedimentation Velocity in the Analytical Ultracentrifuge. Anal Chem 2017; 89:862-870. [PMID: 27977168 PMCID: PMC5505516 DOI: 10.1021/acs.analchem.6b03926] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Interactions between nucleic acids and proteins are critical for many cellular processes, and their study is of utmost importance to many areas of biochemistry, cellular biology, and virology. Here, we introduce a new analytical method based on sedimentation velocity (SV) analytical ultracentrifugation, in combination with a novel multiwavelength detector to characterize such interactions. We identified the stoichiometry and molar mass of a complex formed during the interaction of a West Nile virus RNA stem loop structure with the human T cell-restricted intracellular antigen-1 related protein. SV has long been proven as a powerful technique for studying dynamic assembly processes under physiological conditions in solution. Here, we demonstrate, for the first time, how the new multiwavelength technology can be exploited to study protein-RNA interactions, and show how the spectral information derived from the new detector complements the traditional hydrodynamic information from analytical ultracentrifugation. Our method allows the protein and nucleic acid signals to be separated by spectral decomposition such that sedimentation information from each individual species, including any complexes, can be clearly identified based on their spectral signatures. The method presented here extends to any interacting system where the interaction partners are spectrally separable.
Collapse
Affiliation(s)
- Jin Zhang
- Georgia State University, Department of Chemistry, 50 Decatur St. SE, Atlanta, Georgia 30303, United States
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Joseph Z. Pearson
- University of Konstanz, Department of Chemistry, Physical Chemistry, Universitätsstraße 10, Box 714, D-78457 Konstanz, Germany
| | - Gary E. Gorbet
- The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7760, San Antonio, Texas 78229-3901, United States
| | - Helmut Cölfen
- University of Konstanz, Department of Chemistry, Physical Chemistry, Universitätsstraße 10, Box 714, D-78457 Konstanz, Germany
| | - Markus W. Germann
- Georgia State University, Department of Chemistry, 50 Decatur St. SE, Atlanta, Georgia 30303, United States
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Margo A. Brinton
- Georgia State University, Department of Biology, P.O. 4010, Atlanta, Georgia 30303, United States
| | - Borries Demeler
- The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7760, San Antonio, Texas 78229-3901, United States
| |
Collapse
|
21
|
Izumikawa K, Yoshikawa H, Ishikawa H, Nobe Y, Yamauchi Y, Philipsen S, Simpson RJ, Isobe T, Takahashi N. Chtop (Chromatin target of Prmt1) auto-regulates its expression level via intron retention and nonsense-mediated decay of its own mRNA. Nucleic Acids Res 2016; 44:9847-9859. [PMID: 27683223 PMCID: PMC5175361 DOI: 10.1093/nar/gkw831] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/05/2016] [Accepted: 09/06/2016] [Indexed: 12/25/2022] Open
Abstract
Chtop (chromatin target of Prmt1) regulates various aspects of gene expression including transcription and mRNA export. Despite these important functions, the regulatory mechanism underlying Chtop expression remains undetermined. Using Chtop-expressing human cell lines, we demonstrate that Chtop expression is controlled via an autoregulatory negative feedback loop whereby Chtop binds its own mRNA to retain intron 2 during splicing; a premature termination codon present at the 5′ end of intron 2 leads to nonsense-mediated decay of the mRNA. We also show that Chtop interacts with exon 2 of Chtop mRNA via its arginine-glycine-rich (RG) domain, and with intron 2 via its N-terminal (N1) domain; both are required for retention of intron 2. In addition, we show that hnRNP H accelerates intron 2 splicing of Chtop mRNA in a manner dependent on Chtop expression level, suggesting that Chtop and hnRNP H regulate intron 2 retention of Chtop mRNA antagonistically. Thus, the present study provides a novel molecular mechanism by which mRNA and protein levels are constitutively regulated by intron retention.
Collapse
Affiliation(s)
- Keiichi Izumikawa
- Department of Applied Biological Science, United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Harunori Yoshikawa
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Hideaki Ishikawa
- Department of Applied Biological Science, United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yuko Nobe
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.,Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Yoshio Yamauchi
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.,Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Sjaak Philipsen
- Department of Cell Biology, Erasmus MC, 3015 GE Rotterdam, The Netherlands
| | - Richard J Simpson
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,La Trobe Institute for Molecular Science (LIMS) LIMS Building 1, Room 412 La Trobe University, Bundoora, Victoria 3086, Australia
| | - Toshiaki Isobe
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.,Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo 192-0397, Japan
| | - Nobuhiro Takahashi
- Department of Applied Biological Science, United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan .,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| |
Collapse
|
22
|
Tang SJ, Luo S, Ho JXJ, Ly PT, Goh E, Roca X. Characterization of the Regulation of CD46 RNA Alternative Splicing. J Biol Chem 2016; 291:14311-14323. [PMID: 27226545 DOI: 10.1074/jbc.m115.710350] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Indexed: 11/06/2022] Open
Abstract
Here we present a detailed analysis of the alternative splicing regulation of human CD46, which generates different isoforms with distinct functions. CD46 is a ubiquitous membrane protein that protects host cells from complement and plays other roles in immunity, autophagy, and cell adhesion. CD46 deficiency causes an autoimmune disorder, and this protein is also involved in pathogen infection and cancer. Before this study, the mechanisms of CD46 alternative splicing remained unexplored even though dysregulation of this process has been associated with autoimmune diseases. We proved that the 5' splice sites of CD46 cassette exons 7 and 8 encoding extracellular domains are defined by noncanonical mechanisms of base pairing to U1 small nuclear RNA. Next we characterized the regulation of CD46 cassette exon 13, whose inclusion or skipping generates different cytoplasmic tails with distinct functions. Using splicing minigenes, we identified multiple exonic and intronic splicing enhancers and silencers that regulate exon 13 inclusion via trans-acting splicing factors like PTBP1 and TIAL1. Interestingly, a common splicing activator such as SRSF1 appears to repress CD46 exon 13 inclusion. We also report that expression of CD46 mRNA isoforms is further regulated by non-sense-mediated mRNA decay and transcription speed. Finally, we successfully manipulated CD46 exon 13 inclusion using antisense oligonucleotides, opening up opportunities for functional studies of the isoforms as well as for therapeutics for autoimmune diseases. This study provides insight into CD46 alternative splicing regulation with implications for its function in the immune system and for genetic disease.
Collapse
Affiliation(s)
- Sze Jing Tang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Shufang Luo
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Jia Xin Jessie Ho
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Phuong Thao Ly
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Eling Goh
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| |
Collapse
|
23
|
Abstract
The U2AF heterodimer is generally accepted to play a vital role in defining functional 3' splice sites in pre-mRNA splicing. Given prevalent mutations in U2AF, particularly in the U2AF1 gene (which encodes for the U2AF35 subunit) in blood disorders and other human cancers, there are renewed interests in these classic splicing factors to further understand their regulatory functions in RNA metabolism in both physiological and disease settings. We recently reported that U2AF has a maximal capacity to directly bind ˜88% of functional 3' splice sites in the human genome and that numerous U2AF binding events also occur in various exonic and intronic locations, thus providing additional mechanisms for the regulation of alternative splicing besides their traditional role in titrating weak splice sites in the cell. These findings, coupled with the existence of multiple related proteins to both U2AF65 and U2AF35, beg a series of questions on the universal role of U2AF in functional 3' splice site definition, their binding specificities in vivo, potential mechanisms to bypass their requirement for certain intron removal events, contribution of splicing-independent functions of U2AF to important cellular functions, and the mechanism for U2AF mutations to invoke specific diseases in humans.
Collapse
Affiliation(s)
- Tongbin Wu
- a Department of Medicine ; University of California, San Diego ; La Jolla , CA USA
| | | |
Collapse
|
24
|
Regulation of gene expression through production of unstable mRNA isoforms. Biochem Soc Trans 2015; 42:1196-205. [PMID: 25110025 DOI: 10.1042/bst20140102] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alternative splicing is universally accredited for expanding the information encoded within the transcriptome. In recent years, several tightly regulated alternative splicing events have been reported which do not lead to generation of protein products, but lead to unstable mRNA isoforms. Instead these transcripts are targets for NMD (nonsense-mediated decay) or retained in the nucleus and degraded. In the present review I discuss the regulation of these events, and how many have been implicated in control of gene expression that is instrumental to a number of developmental paradigms. I further discuss their relevance to disease settings and conclude by highlighting technologies that will aid identification of more candidate events in future.
Collapse
|
25
|
Sánchez-Jiménez C, Ludeña MD, Izquierdo JM. T-cell intracellular antigens function as tumor suppressor genes. Cell Death Dis 2015; 6:e1669. [PMID: 25741594 PMCID: PMC4385921 DOI: 10.1038/cddis.2015.43] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 12/16/2014] [Accepted: 01/19/2015] [Indexed: 12/12/2022]
Abstract
Knockdown of T-cell intracellular antigens TIA1 and TIAR in transformed cells triggers cell proliferation and tumor growth. Using a tetracycline-inducible system, we report here that an increased expression of TIA1 or TIAR in 293 cells results in reduced rates of cell proliferation. Ectopic expression of these proteins abolish endogenous TIA1 and TIAR levels via the regulation of splicing of their pre-mRNAs, and partially represses global translation in a phospho-eukaryotic initiation factor 2 alpha-dependent manner. This is accompanied by cell cycle arrest at G1/S and cell death through caspase-dependent apoptosis and autophagy. Genome-wide profiling illustrates a selective upregulation of p53 signaling pathway-related genes. Nude mice injected with doxycycline-inducible cells expressing TIA1 or TIAR retard, or even inhibit, growth of xenotumors. Remarkably, low expressions of TIA1 and TIAR correlate with poor prognosis in patients with lung squamous cell carcinoma. These findings strongly support the concept that TIA proteins act as tumor suppressor genes.
Collapse
Affiliation(s)
- C Sánchez-Jiménez
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/ Nicolás Cabrera 1, Madrid, Spain
| | - M D Ludeña
- Facultad de Medicina, Departamento de Biología Celular y Patología, Universidad de Salamanca-Hospital Universitario de Salamanca, C/ Paseo de San Vicente 58-182, Salamanca, Spain
| | - J M Izquierdo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid (CSIC/UAM), C/ Nicolás Cabrera 1, Madrid, Spain
| |
Collapse
|
26
|
Hamdollah Zadeh MA, Amin EM, Hoareau-Aveilla C, Domingo E, Symonds KE, Ye X, Heesom KJ, Salmon A, D'Silva O, Betteridge KB, Williams AC, Kerr DJ, Salmon AHJ, Oltean S, Midgley RS, Ladomery MR, Harper SJ, Varey AHR, Bates DO. Alternative splicing of TIA-1 in human colon cancer regulates VEGF isoform expression, angiogenesis, tumour growth and bevacizumab resistance. Mol Oncol 2015; 9:167-78. [PMID: 25224594 PMCID: PMC4286123 DOI: 10.1016/j.molonc.2014.07.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/23/2014] [Accepted: 07/24/2014] [Indexed: 02/06/2023] Open
Abstract
The angiogenic capability of colorectal carcinomas (CRC), and their susceptibility to anti-angiogenic therapy, is determined by expression of vascular endothelial growth factor (VEGF) isoforms. The intracellular protein T-cell Intracellular Antigen (TIA-1) alters post-transcriptional RNA processing and binds VEGF-A mRNA. We therefore tested the hypothesis that TIA-1 could regulate VEGF-A isoform expression in colorectal cancers. TIA-1 and VEGF-A isoform expression was measured in colorectal cancers and cell lines. We discovered that an endogenous splice variant of TIA-1 encoding a truncated protein, short TIA-1 (sTIA-1) was expressed in CRC tissues and invasive K-Ras mutant colon cancer cells and tissues but not in adenoma cell lines. sTIA-1 was more highly expressed in CRC than in normal tissues and increased with tumour stage. Knockdown of sTIA-1 or over-expression of full length TIA-1 (flTIA-1) induced expression of the anti-angiogenic VEGF isoform VEGF-A165b. Whereas flTIA-1 selectively bound VEGF-A165 mRNA and increased translation of VEGF-A165b, sTIA-1 prevented this binding. In nude mice, xenografted colon cancer cells over-expressing flTIA-1 formed smaller, less vascular tumours than those expressing sTIA-1, but flTIA-1 expression inhibited the effect of anti-VEGF antibodies. These results indicate that alternative splicing of an RNA binding protein can regulate isoform specific expression of VEGF providing an added layer of complexity to the angiogenic profile of colorectal cancer and their resistance to anti-angiogenic therapy.
Collapse
Affiliation(s)
- Maryam A Hamdollah Zadeh
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Elianna M Amin
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Coralie Hoareau-Aveilla
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Enric Domingo
- Molecular and Population Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Kirsty E Symonds
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Xi Ye
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Katherine J Heesom
- Proteomics Facility, Faculty of Veterinary and Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Andrew Salmon
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Olivia D'Silva
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Kai B Betteridge
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Ann C Williams
- School of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - David J Kerr
- Nuffield Dept Clinical and Laboratory Sciences, University of Oxford, UK
| | - Andrew H J Salmon
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Sebastian Oltean
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Rachel S Midgley
- Molecular and Population Genetics, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Michael R Ladomery
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, University of the West of England, Bristol BS16 1QY, UK
| | - Steven J Harper
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - Alexander H R Varey
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK
| | - David O Bates
- Microvascular Research Laboratories, Veterinary Sciences Building, School of Physiology and Pharmacology, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK; Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, NG7 2UH, UK.
| |
Collapse
|
27
|
RNA recognition and stress granule formation by TIA proteins. Int J Mol Sci 2014; 15:23377-88. [PMID: 25522169 PMCID: PMC4284772 DOI: 10.3390/ijms151223377] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 12/05/2014] [Accepted: 12/11/2014] [Indexed: 02/04/2023] Open
Abstract
Stress granule (SG) formation is a primary mechanism through which gene expression is rapidly modulated when the eukaryotic cell undergoes cellular stresses (including heat, oxidative, viral infection, starvation). In particular, the sequestration of specifically targeted translationally stalled mRNAs into SGs limits the expression of a subset of genes, but allows the expression of heatshock proteins that have a protective effect in the cell. The importance of SGs is seen in several disease states in which SG function is disrupted. Fundamental to SG formation are the T cell restricted intracellular antigen (TIA) proteins (TIA-1 and TIA-1 related protein (TIAR)), that both directly bind to target RNA and self-associate to seed the formation of SGs. Here a summary is provided of the current understanding of the way in which TIA proteins target specific mRNA, and how TIA self-association is triggered under conditions of cellular stress.
Collapse
|
28
|
A posttranscriptional mechanism that controls Ptbp1 abundance in the Xenopus epidermis. Mol Cell Biol 2014; 35:758-68. [PMID: 25512611 DOI: 10.1128/mcb.01040-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The output of alternative splicing depends on the cooperative or antagonistic activities of several RNA-binding proteins (RBPs), like Ptbp1 and Esrp1 in Xenopus. Fine-tuning of the RBP abundance is therefore of prime importance to achieve tissue- or cell-specific splicing patterns. Here, we addressed the mechanisms leading to the high expression of the ptbp1 gene, which encodes Ptbp1, in Xenopus epidermis. Two splice isoforms of ptbp1 mRNA differ by the presence of an alternative exon 11, and only the isoform including exon 11 can be translated to a full-length protein. In vivo minigene assays revealed that the nonproductive isoform was predominantly produced. Knockdown experiments demonstrated that Esrp1, which is specific to the epidermis, strongly stimulated the expression of ptbp1 by favoring the productive isoform. Consequently, knocking down esrp1 phenocopied ptbp1 inactivation. Conversely, Ptbp1 repressed the expression of its own gene by favoring the nonproductive isoform. Hence, a complex posttranscriptional mechanism controls Ptbp1 abundance in Xenopus epidermis: skipping of exon 11 is the default splicing pattern, but Esrp1 stimulates ptbp1 expression by favoring the inclusion of exon 11 up to a level that is limited by Ptbp1 itself. These results decipher a posttranscriptional mechanism that achieves various abundances of the ubiquitous RBP Ptbp1 in different tissues.
Collapse
|
29
|
Shao C, Yang B, Wu T, Huang J, Tang P, Zhou Y, Zhou J, Qiu J, Jiang L, Li H, Chen G, Sun H, Zhang Y, Denise A, Zhang DE, Fu XD. Mechanisms for U2AF to define 3' splice sites and regulate alternative splicing in the human genome. Nat Struct Mol Biol 2014; 21:997-1005. [PMID: 25326705 PMCID: PMC4429597 DOI: 10.1038/nsmb.2906] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/25/2014] [Indexed: 12/24/2022]
Abstract
The U2AF heterodimer has been well studied for its role in defining functional 3' splice sites in pre-mRNA splicing, but many fundamental questions still remain unaddressed regarding the function of U2AF in mammalian genomes. Through genome-wide analysis of U2AF-RNA interactions, we report that U2AF has the capacity to directly define ~88% of functional 3' splice sites in the human genome, but numerous U2AF binding events also occur in intronic locations. Mechanistic dissection reveals that upstream intronic binding events interfere with the immediate downstream 3' splice site associated either with the alternative exon, to cause exon skipping, or with the competing constitutive exon, to induce exon inclusion. We further demonstrate partial functional impairment with leukemia-associated mutations in U2AF35, but not U2AF65, in regulated splicing. These findings reveal the genomic function and regulatory mechanism of U2AF in both normal and disease states.
Collapse
Affiliation(s)
- Changwei Shao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Bo Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Laboratoire de Recherche en Informatique, Institut de Génétique et Microbiologie I, Université Paris-Sud and Centre National de la Recherche Scientifique, Orsay, France
| | - Tongbin Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Huang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Peng Tang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yu Zhou
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jie Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jinsong Qiu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Li Jiang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hairi Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Geng Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hui Sun
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yi Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Alain Denise
- Laboratoire de Recherche en Informatique, Institut de Génétique et Microbiologie I, Université Paris-Sud and Centre National de la Recherche Scientifique, Orsay, France
| | - Dong-Er Zhang
- UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, California, USA
| | - Xiang-Dong Fu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| |
Collapse
|
30
|
Genome-wide profiling reveals a role for T-cell intracellular antigens TIA1 and TIAR in the control of translational specificity in HeLa cells. Biochem J 2014; 461:43-50. [PMID: 24927121 DOI: 10.1042/bj20140227] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TIA (T-cell intracellular antigens)-knockdown HeLa cells show an increase in ribosomes and translational machinery components. This increase correlates with specific changes in translationally up-regulated mRNAs involved in cell-cycle progression and DNA repair, as shown in polysomal profiling analysis. Our data support the hypothesis that a concerted activation of both global and selective translational rates leads to the transition to a more proliferative status in TIA-knockdown HeLa cells.
Collapse
|
31
|
Abstract
The tight regulation of splicing networks is critical to development. To maintain robust splicing patterns, many splicing factors autoregulate their expression through alternative splicing-coupled nonsense-mediated decay (AS-NMD). Here, Jangi et al. globally characterize the function of the splicing regulator Rbfox2 in mouse embryonic stem cells. They show that Rbfox2 cross-regulates AS-NMD events within RNA-binding proteins to alter their expression. This study positions Rbfox2 at a critical node in a broader splicing regulatory network, with roles in both normal development and disease. The tight regulation of splicing networks is critical for organismal development. To maintain robust splicing patterns, many splicing factors autoregulate their expression through alternative splicing-coupled nonsense-mediated decay (AS-NMD). However, as negative autoregulation results in a self-limiting window of splicing factor expression, it is unknown how variations in steady-state protein levels can arise in different physiological contexts. Here, we demonstrate that Rbfox2 cross-regulates AS-NMD events within RNA-binding proteins to alter their expression. Using individual nucleotide-resolution cross-linking immunoprecipitation coupled to high-throughput sequencing (iCLIP) and mRNA sequencing, we identified >200 AS-NMD splicing events that are bound by Rbfox2 in mouse embryonic stem cells. These “silent” events are characterized by minimal apparent splicing changes but appreciable changes in gene expression upon Rbfox2 knockdown due to degradation of the NMD-inducing isoform. Nearly 70 of these AS-NMD events fall within genes encoding RNA-binding proteins, many of which are autoregulated. As with the coding splicing events that we found to be regulated by Rbfox2, silent splicing events are evolutionarily conserved and frequently contain the Rbfox2 consensus UGCAUG. Our findings uncover an unexpectedly broad and multilayer regulatory network controlled by Rbfox2 and offer an explanation for how autoregulatory splicing networks are tuned.
Collapse
|
32
|
Bembich S, Herzog JS, De Conti L, Stuani C, Avendaño-Vázquez SE, Buratti E, Baralle M, Baralle FE. Predominance of spliceosomal complex formation over polyadenylation site selection in TDP-43 autoregulation. Nucleic Acids Res 2013; 42:3362-71. [PMID: 24369426 PMCID: PMC3950720 DOI: 10.1093/nar/gkt1343] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
TDP-43 is a nuclear protein involved in many aspects of RNA metabolism. To ensure cellular viability, its expression levels within cells must be tightly regulated. We have previously demonstrated that TDP-43 autoregulation occurs through the activation of a normally silent intron in its 3′-UTR sequence that results in the use of alternative polyadenylation sites. In this work, we analyse which is the dominant event in autoregulation: the recognition of the splice sites of 3′-UTR intron 7 or the intrinsic quality of the alternative polyadenylation sites. A panel of minigene constructs was tested for autoregulation functionality, protein production and subcellular messenger RNA localization. Our data clearly indicate that constitutive spliceosome complex formation across intron 7 does not lead to high protein production but, on the contrary, to lower TDP-43 messenger RNA and protein levels. This is due to altered nucleocytoplasmic distribution of the RNA that is mostly retained in the nucleus and degraded. This study provides a novel in-depth characterization of how RNA binding proteins can autoregulate their own levels within cells, an essential regulatory process in maintaining cellular viability.
Collapse
Affiliation(s)
- Sara Bembich
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Silva-García CG, Estela Navarro R. The C. elegans TIA-1/TIAR homolog TIAR-1 is required to induce germ cell apoptosis. Genesis 2013; 51:690-707. [PMID: 23913578 DOI: 10.1002/dvg.22418] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/20/2013] [Accepted: 07/22/2013] [Indexed: 11/11/2022]
Abstract
In Caenorhabditis elegans, physiological germ cell apoptosis eliminates more than half of the cells in the hermaphrodite gonad to support gamete quality and germline homeostasis by a still unidentified mechanism. External factors can also affect germ cell apoptosis. The BH3-only protein EGL-1 induces germ cell apoptosis when animals are exposed to pathogens or agents that produce DNA damage. DNA damage-induced apoptosis also requires the nematode p53 homolog CEP-1. Previously, we found that heat shock, oxidative, and osmotic stresses induce germ cell apoptosis through an EGL-1 and CEP-1 independent mechanism that requires the MAPKK pathway. However, we observed that starvation increases germ cell apoptosis by an unknown pathway. Searching for proteins that participate in stress-induced apoptosis, we found the RNA-binding protein TIAR-1 (a homolog of the mammalian TIA-1/TIAR family of proteins). Here, we show that TIAR-1 in C. elegans is required to induce apoptosis in the germline under several conditions. We also show that TIAR-1 acts downstream of CED-9 (a BCL2 homolog) to induce apoptosis under stress conditions, and apparently does not seem to regulate ced-4 or ced-3 mRNAs accumulation directly. TIAR-1 is expressed ubiquitously in the cytoplasm of the soma as well as the germline, where it sometimes associates with P granules. We show that animals lacking TIAR-1 expression are temperature sensitive sterile due to oogenesis and spermatogenesis defects. Our work shows that TIAR-1 is required for proper germline function and demonstrates that this protein is important to induce germ cell apoptosis under several conditions.
Collapse
Affiliation(s)
- Carlos Giovanni Silva-García
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México
| | | |
Collapse
|
34
|
Melamed Z, Levy A, Ashwal-Fluss R, Lev-Maor G, Mekahel K, Atias N, Gilad S, Sharan R, Levy C, Kadener S, Ast G. Alternative splicing regulates biogenesis of miRNAs located across exon-intron junctions. Mol Cell 2013; 50:869-81. [PMID: 23747012 DOI: 10.1016/j.molcel.2013.05.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 03/25/2013] [Accepted: 04/30/2013] [Indexed: 12/16/2022]
Abstract
The initial step in microRNA (miRNA) biogenesis requires processing of the precursor miRNA (pre-miRNA) from a longer primary transcript. Many pre-miRNAs originate from introns, and both a mature miRNA and a spliced RNA can be generated from the same transcription unit. We have identified a mechanism in which RNA splicing negatively regulates the processing of pre-miRNAs that overlap exon-intron junctions. Computational analysis identified dozens of such pre-miRNAs, and experimental validation demonstrated competitive interaction between the Microprocessor complex and the splicing machinery. Tissue-specific alternative splicing regulates maturation of one such miRNA, miR-412, resulting in effects on its targets that code a protein network involved in neuronal cell death processes. This mode of regulation specifically controls maturation of splice-site-overlapping pre-miRNAs but not pre-miRNAs located completely within introns or exons of the same transcript. Our data present a biological role of alternative splicing in regulation of miRNA biogenesis.
Collapse
Affiliation(s)
- Ze'ev Melamed
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Kim HS, Headey SJ, Yoga YMK, Scanlon MJ, Gorospe M, Wilce MCJ, Wilce JA. Distinct binding properties of TIAR RRMs and linker region. RNA Biol 2013; 10:579-89. [PMID: 23603827 PMCID: PMC3710364 DOI: 10.4161/rna.24341] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The RNA-binding protein TIAR is an mRNA-binding protein that acts as a translational repressor, particularly important under conditions of cellular stress. It binds to target mRNA and DNA via its RNA recognition motif (RRM) domains and is involved in both splicing regulation and translational repression via the formation of "stress granules." TIAR has also been shown to bind ssDNA and play a role in the regulation of transcription. Here we show, using surface plasmon resonance and nuclear magnetic resonance spectroscopy, specific roles of individual TIAR domains for high-affinity binding to RNA and DNA targets. We confirm that RRM2 of TIAR is the major RNA- and DNA-binding domain. However, the strong nanomolar affinity binding to U-rich RNA and T-rich DNA depends on the presence of the six amino acid residues found in the linker region C-terminal to RRM2. On its own, RRM1 shows preferred binding to DNA over RNA. We further characterize the interaction between RRM2 with the C-terminal extension and an AU-rich target RNA sequence using NMR spectroscopy to identify the amino acid residues involved in binding. We demonstrate that TIAR RRM2, together with its C-terminal extension, is the major contributor for the high-affinity (nM) interactions of TIAR with target RNA sequences.
Collapse
Affiliation(s)
- Henry S Kim
- Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | | | | | | | | | | | | |
Collapse
|
36
|
Hackman P, Sarparanta J, Lehtinen S, Vihola A, Evilä A, Jonson PH, Luque H, Kere J, Screen M, Chinnery PF, Åhlberg G, Edström L, Udd B. Welander distal myopathy is caused by a mutation in the RNA-binding protein TIA1. Ann Neurol 2013; 73:500-9. [PMID: 23401021 DOI: 10.1002/ana.23831] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/14/2012] [Accepted: 11/30/2012] [Indexed: 12/11/2022]
Abstract
OBJECTIVE A study was undertaken to identify the molecular cause of Welander distal myopathy (WDM), a classic autosomal dominant distal myopathy. METHODS The genetic linkage was confirmed and defined by microsatellite and single nucleotide polymorphism haplotyping. The whole linked genomic region was sequenced with targeted high-throughput and Sanger sequencing, and coding transcripts were sequenced on the cDNA level. WDM muscle biopsies were studied by Western blotting and immunofluorescence microscopy. Splicing of TIA1 and its target genes in muscle and myoblast cultures was analyzed by reverse transcriptase polymerase chain reaction. Mutant TIA1 was characterized by cell biological studies on HeLa cells, including quantification of stress granules by high content analysis and fluorescence recovery after photobleaching (FRAP) experiments. RESULTS The linked haplotype at 2p13 was narrowed down to <806 kb. Sequencing by multiple methods revealed only 1 segregating coding mutation, c.1362 G>A (p.E384K) in the RNA-binding protein TIA1, a key component of stress granules. Immunofluorescence microscopy of WDM biopsies showed a focal increase of TIA1 in atrophic and vacuolated fibers. In HeLa cells, mutant TIA1 constructs caused a mild increase in stress granule abundance compared to wild type, and showed slower average fluorescence recovery in FRAP. INTERPRETATION WDM is caused by mutated TIA1 through a dominant pathomechanism probably involving altered stress granule dynamics.
Collapse
Affiliation(s)
- Peter Hackman
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Damgaard CK, Lykke-Andersen J. Regulation of ARE-mRNA Stability by Cellular Signaling: Implications for Human Cancer. Cancer Treat Res 2013; 158:153-80. [PMID: 24222358 DOI: 10.1007/978-3-642-31659-3_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
During recent years, it has become clear that regulation of mRNA stability is an important event in the control of gene expression. The stability of a large class of mammalian mRNAs is regulated by AU-rich elements (AREs) located in the mRNA 3' UTRs. mRNAs with AREs are inherently labile but as a response to different cellular cues they can become either stabilized, allowing expression of a given gene, or further destabilized to silence their expression. These tightly regulated mRNAs include many that encode growth factors, proto-oncogenes, cytokines, and cell cycle regulators. Failure to properly regulate their stability can therefore lead to uncontrolled expression of factors associated with cell proliferation and has been implicated in several human cancers. A number of transfactors that recognize AREs and regulate the translation and degradation of ARE-mRNAs have been identified. These transfactors are regulated by signal transduction pathways, which are often misregulated in cancers. This chapter focuses on the function of ARE-binding proteins with an emphasis on their regulation by signaling pathways and the implications for human cancer.
Collapse
|
38
|
Thomas J, Palusa SG, Prasad KVSK, Ali GS, Surabhi GK, Ben-Hur A, Abdel-Ghany SE, Reddy ASN. Identification of an intronic splicing regulatory element involved in auto-regulation of alternative splicing of SCL33 pre-mRNA. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:935-46. [PMID: 22913769 DOI: 10.1111/tpj.12004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In Arabidopsis, pre-mRNAs of serine/arginine-rich (SR) proteins undergo extensive alternative splicing (AS). However, little is known about the cis-elements and trans-acting proteins involved in regulating AS. Using a splicing reporter (GFP-intron-GFP), consisting of the GFP coding sequence interrupted by an alternatively spliced intron of SCL33, we investigated whether cis-elements within this intron are sufficient for AS, and which SR proteins are necessary for regulated AS. Expression of the splicing reporter in protoplasts faithfully produced all splice variants from the intron, suggesting that cis-elements required for AS reside within the intron. To determine which SR proteins are responsible for AS, the splicing pattern of the GFP-intron-GFP reporter was investigated in protoplasts of three single and three double mutants of SR genes. These analyses revealed that SCL33 and a closely related paralog, SCL30a, are functionally redundant in generating specific splice variants from this intron. Furthermore, SCL33 protein bound to a conserved sequence in this intron, indicating auto-regulation of AS. Mutations in four GAAG repeats within the conserved region impaired generation of the same splice variants that are affected in the scl33 scl30a double mutant. In conclusion, we have identified the first intronic cis-element involved in AS of a plant SR gene, and elucidated a mechanism for auto-regulation of AS of this intron.
Collapse
Affiliation(s)
- Julie Thomas
- Department of Biology, Program in Molecular Plant Biology, Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USADepartment of Computer Science and Program in Molecular Plant Biology, Colorado State University, Fort Collins, CO 80523, USA
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Induction of stress granule-like structures in vesicular stomatitis virus-infected cells. J Virol 2012; 87:372-83. [PMID: 23077311 DOI: 10.1128/jvi.02305-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Previous studies from our laboratory revealed that cellular poly(C) binding protein 2 (PCBP2) downregulates vesicular stomatitis virus (VSV) gene expression. We show here that VSV infection induces the formation of granular structures in the cytoplasm containing cellular RNA-binding proteins, including PCBP2, T-cell-restricted intracellular antigen 1 (TIA1), and TIA1-related protein (TIAR). Depletion of TIA1 via small interfering RNAs (siRNAs), but not depletion of TIAR, results in enhanced VSV growth and gene expression. The VSV-induced granules appear to be similar to the stress granules (SGs) generated in cells triggered by heat shock or oxidative stress but do not contain some of the bona fide SG markers, such as eukaryotic initiation factor 3 (eIF3) or eIF4A, or the processing body (PB) markers, such as mRNA-decapping enzyme 1A (DCP1a), and thus may not represent canonical SGs or PBs. Our results revealed that the VSV-induced granules, called SG-like structures here, contain the viral replicative proteins and RNAs. The formation and maintenance of the SG-like structures required viral replication and ongoing protein synthesis, but an intact cytoskeletal network was not necessary. These results suggest that cells respond to VSV infection by aggregating the antiviral proteins, such as PCBP2 and TIA1, to form SG-like structures. The functional significance of these SG-like structures in VSV-infected cells is currently under investigation.
Collapse
|
40
|
Ortuño-Pineda C, Galindo-Rosales JM, Calderón-Salinas JV, Villegas-Sepúlveda N, Saucedo-Cárdenas O, De Nova-Ocampo M, Valdés J. Binding of hnRNP H and U2AF65 to respective G-codes and a poly-uridine tract collaborate in the N50-5'ss selection of the REST N exon in H69 cells. PLoS One 2012; 7:e40315. [PMID: 22792276 PMCID: PMC3390395 DOI: 10.1371/journal.pone.0040315] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/04/2012] [Indexed: 11/19/2022] Open
Abstract
The splicing of the N exon in the pre-mRNA coding for the RE1-silencing transcription factor (REST) results in a truncated protein that modifies the expression pattern of some of its target genes. A weak 3'ss, three alternative 5'ss (N4-, N50-, and N62-5'ss) and a variety of putative target sites for splicing regulatory proteins are found around the N exon; two GGGG codes (G2-G3) and a poly-Uridine tract (N-PU) are found in front of the N50-5'ss. In this work we analyzed some of the regulatory factors and elements involved in the preferred selection of the N50-5'ss (N50 activation) in the small cell lung cancer cell line H69. Wild type and mutant N exon/β-globin minigenes recapitulated N50 exon splicing in H69 cells, and showed that the N-PU and the G2-G3 elements are required for N50 exon splicing. Biochemical and knockdown experiments identified these elements as U2AF65 and hnRNP H targets, respectively, and that they are also required for N50 exon activation. Compared to normal MRC5 cells, and in keeping with N50 exon activation, U2AF65, hnRNP H and other splicing factors were highly expressed in H69 cells. CLIP experiments revealed that hnRNP H RNA-binding occurs first and is a prerequisite for U2AF65 RNA binding, and EMSA and CLIP experiments suggest that U2AF65-RNA recognition displaces hnRNP H and helps to recruit other splicing factors (at least U1 70K) to the N50-5'ss. Our results evidenced novel hnRNP H and U2AF65 functions: respectively, U2AF65-recruiting to a 5'ss in humans and the hnRNP H-displacing function from two juxtaposed GGGG codes.
Collapse
Affiliation(s)
- Carlos Ortuño-Pineda
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., México
| | | | | | - Nicolás Villegas-Sepúlveda
- D1epartamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., México
| | - Odila Saucedo-Cárdenas
- Departamento de Histología, Facultad de Medicina, Universidad Autónoma de Nuevo Léon, Monterrey N.L. México
- División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey N.L., México
| | - Mónica De Nova-Ocampo
- Programa Institucional de Biomedicina Molecular, Escuela Nacional de Medicina y Homeopatía-IPN, México D.F., México
| | - Jesús Valdés
- Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., México
- * E-mail:
| |
Collapse
|
41
|
López-Urrutia E, Valdés J, Bonilla-Moreno R, Martínez-Salazar M, Martínez-Garcia M, Berumen J, Villegas-Sepúlveda N. A few nucleotide polymorphisms are sufficient to recruit nuclear factors differentially to the intron 1 of HPV-16 intratypic variants. Virus Res 2012; 166:43-53. [DOI: 10.1016/j.virusres.2012.02.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 02/28/2012] [Accepted: 02/28/2012] [Indexed: 01/24/2023]
|
42
|
Welzel F, Kaehler C, Isau M, Hallen L, Lehrach H, Krobitsch S. FOX-2 dependent splicing of ataxin-2 transcript is affected by ataxin-1 overexpression. PLoS One 2012; 7:e37985. [PMID: 22666429 PMCID: PMC3364202 DOI: 10.1371/journal.pone.0037985] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 04/27/2012] [Indexed: 12/03/2022] Open
Abstract
Alternative splicing is a fundamental posttranscriptional mechanism for controlling gene expression, and splicing defects have been linked to various human disorders. The splicing factor FOX-2 is part of a main protein interaction hub in a network related to human inherited ataxias, however, its impact remains to be elucidated. Here, we focused on the reported interaction between FOX-2 and ataxin-1, the disease-causing protein in spinocerebellar ataxia type 1. In this line, we further evaluated this interaction by yeast-2-hybrid analyses and co-immunoprecipitation experiments in mammalian cells. Interestingly, we discovered that FOX-2 localization and splicing activity is affected in the presence of nuclear ataxin-1 inclusions. Moreover, we observed that FOX-2 directly interacts with ataxin-2, a protein modulating spinocerebellar ataxia type 1 pathogenesis. Finally, we provide evidence that splicing of pre-mRNA of ataxin-2 depends on FOX-2 activity, since reduction of FOX-2 levels led to increased skipping of exon 18 in ataxin-2 transcripts. Most striking, we observed that ataxin-1 overexpression has an effect on this splicing event as well. Thus, our results demonstrate that FOX-2 is involved in splicing of ataxin-2 transcripts and that this splicing event is altered by overexpression of ataxin-1.
Collapse
Affiliation(s)
- Franziska Welzel
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Biology, Chemistry and Pharmacy, Free University Berlin, Berlin, Germany
| | - Christian Kaehler
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Biology, Chemistry and Pharmacy, Free University Berlin, Berlin, Germany
| | - Melanie Isau
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
- Department of Biology, Chemistry and Pharmacy, Free University Berlin, Berlin, Germany
| | - Linda Hallen
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Hans Lehrach
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Sylvia Krobitsch
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics, Berlin, Germany
- * E-mail:
| |
Collapse
|
43
|
Ankö ML, Neugebauer KM. RNA-protein interactions in vivo: global gets specific. Trends Biochem Sci 2012; 37:255-62. [PMID: 22425269 DOI: 10.1016/j.tibs.2012.02.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/05/2012] [Accepted: 02/08/2012] [Indexed: 01/01/2023]
Abstract
RNA-binding proteins (RBPs) impact every process in the cell; they act as splicing and polyadenylation factors, transport and localization factors, stabilizers and destabilizers, modifiers, and chaperones. RNA-binding capacity can be attributed to numerous protein domains that bind a limited repertoire of short RNA sequences. How is specificity achieved in cells? Here we focus on recent advances in determining the RNA-binding properties of proteins in vivo and compare these to in vitro determinations, highlighting insights into how endogenous RNA molecules are recognized and regulated. We also discuss the crucial contribution of structural determinations for understanding RNA-binding specificity and mechanisms.
Collapse
Affiliation(s)
- Minna-Liisa Ankö
- Max Planck Institute of Cell Biology and Genetics, Dresden, Germany.
| | | |
Collapse
|
44
|
Buratti E, Baralle FE. TDP-43: new aspects of autoregulation mechanisms in RNA binding proteins and their connection with human disease. FEBS J 2011; 278:3530-8. [DOI: 10.1111/j.1742-4658.2011.08257.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
45
|
Budini M, Buratti E. TDP-43 autoregulation: implications for disease. J Mol Neurosci 2011; 45:473-9. [PMID: 21681666 DOI: 10.1007/s12031-011-9573-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/06/2011] [Indexed: 12/13/2022]
Abstract
TDP-43 is a nuclear protein that has been shown to play a central role in RNA metabolism. In recent years, this protein has become very important in the study of neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration (FTLD). These diseases share, as common feature, the presence of abnormally aggregated, posttranslationally modified, and mislocalized TDP-43 in the cell cytoplasm of both neurons and glial cells. A major question in TDP-43 research is represented by the investigation of the mechanism(s) that trigger this process and its potential consequences. Regarding the first issue, it is likely that relative protein expression levels might play an important role as has been demonstrated for many protein aggregation processes. In fact, the eventual misregulation of TDP-43 expression leading to enhanced protein production might well correlate with enhanced aggregation, and thus results in increasingly harmful gain- or loss-of-function effects on cellular metabolism. For this reason, it is important to determine the mechanisms that act to regulate TDP-43 levels within the cell. In normal conditions, it is now clear that TDP-43 can modulate its own protein levels through a negative feedback loop triggered by binding to its own RNA in the 3'UTR region leading to mRNA degradation. This work discusses how an eventual disruption of this mechanism might affect TDP-43 pathology, focusing in particular on its association with stress granules and intrinsic aggregation properties.
Collapse
Affiliation(s)
- Mauricio Budini
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34012, Trieste, Italy
| | | |
Collapse
|
46
|
Adenovirus and miRNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:660-7. [PMID: 21621026 PMCID: PMC7102710 DOI: 10.1016/j.bbagrm.2011.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/05/2011] [Accepted: 05/09/2011] [Indexed: 01/15/2023]
Abstract
Adenovirus infection has a tremendous
impact on the cellular silencing machinery. Adenoviruses express high
amounts of non-coding virus associated (VA) RNAs able to saturate key
factors of the RNA interference (RNAi) processing pathway, such as
Exportin 5 and Dicer. Furthermore, a proportion of VA RNAs is cleaved by
Dicer into viral microRNAs (mivaRNAs) that can saturate Argonaute, an
essential protein for miRNA function. Thus, processing and function of
cellular miRNAs is blocked in adenoviral-infected cells. However, viral
miRNAs actively target the expression of cellular genes involved in
relevant functions such as cell proliferation, DNA repair or RNA
regulation. Interestingly, the cellular silencing machinery is active at
early times post-infection and can be used to control the adenovirus cell
cycle. This is relevant for therapeutic purposes against adenoviral
infections or when recombinant adenoviruses are used as vectors for gene
therapy. Manipulation of the viral genome allows the use of adenoviral
vectors to express therapeutic miRNAs or to be silenced by the RNAi
machinery leading to safer vectors with a specific tropism. This article
is part of a "Special Issue entitled:MicroRNAs in viral gene
regulation".
Collapse
|
47
|
Saltzman AL, Pan Q, Blencowe BJ. Regulation of alternative splicing by the core spliceosomal machinery. Genes Dev 2011; 25:373-84. [PMID: 21325135 DOI: 10.1101/gad.2004811] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alternative splicing (AS) plays a major role in the generation of proteomic diversity and in gene regulation. However, the role of the basal splicing machinery in regulating AS remains poorly understood. Here we show that the core snRNP (small nuclear ribonucleoprotein) protein SmB/B' self-regulates its expression by promoting the inclusion of a highly conserved alternative exon in its own pre-mRNA that targets the spliced transcript for nonsense-mediated mRNA decay (NMD). Depletion of SmB/B' in human cells results in reduced levels of snRNPs and a striking reduction in the inclusion levels of hundreds of additional alternative exons, with comparatively few effects on constitutive exon splicing levels. The affected alternative exons are enriched in genes encoding RNA processing and other RNA-binding factors, and a subset of these exons also regulate gene expression by activating NMD. Our results thus demonstrate a role for the core spliceosomal machinery in controlling an exon network that appears to modulate the levels of many RNA processing factors.
Collapse
Affiliation(s)
- Arneet L Saltzman
- Banting and Best Department of Medical Research, The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | | | | |
Collapse
|
48
|
The polypyrimidine tract-binding protein affects coronavirus RNA accumulation levels and relocalizes viral RNAs to novel cytoplasmic domains different from replication-transcription sites. J Virol 2011; 85:5136-49. [PMID: 21411518 DOI: 10.1128/jvi.00195-11] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The coronavirus (CoV) discontinuous transcription mechanism is driven by long-distance RNA-RNA interactions between transcription-regulating sequences (TRSs) located at the 5' terminal leader (TRS-L) and also preceding each mRNA-coding sequence (TRS-B). The contribution of host cell proteins to CoV transcription needs additional information. Polypyrimidine tract-binding protein (PTB) was reproducibly identified in association with positive-sense RNAs of transmissible gastroenteritis coronavirus (TGEV) TRS-L and TRS-B by affinity chromatography and mass spectrometry. A temporal regulation of PTB cytoplasmic levels was observed during infection, with a significant increase from 7 to 16 h postinfection being inversely associated with a decrease in viral replication and transcription. Silencing the expression of PTB with small interfering RNA in two cell lines (Huh7 and HEK 293T) led to a significant increase of up to 4-fold in mRNA levels and virus titer, indicating a negative effect of PTB on CoV RNA accumulation. During CoV infection, PTB relocalized from the nucleus to novel cytoplasmic structures different from replication-transcription sites in which stress granule markers T-cell intracellular antigen-1 (TIA-1) and TIA-1-related protein (TIAR) colocalized. PTB was detected in these modified stress granules in TGEV-infected swine testis cells but not in stress granules induced by oxidative stress. Furthermore, viral genomic and subgenomic RNAs were detected in association with PTB and TIAR. These cytoplasmic ribonucleoprotein complexes might be involved in posttranscriptional regulation of virus gene expression.
Collapse
|
49
|
Kim HS, Wilce MCJ, Yoga YMK, Pendini NR, Gunzburg MJ, Cowieson NP, Wilson GM, Williams BRG, Gorospe M, Wilce JA. Different modes of interaction by TIAR and HuR with target RNA and DNA. Nucleic Acids Res 2011; 39:1117-30. [PMID: 21233170 PMCID: PMC3035456 DOI: 10.1093/nar/gkq837] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
TIAR and HuR are mRNA-binding proteins that play important roles in the regulation of translation. They both possess three RNA recognition motifs (RRMs) and bind to AU-rich elements (AREs), with seemingly overlapping specificity. Here we show using SPR that TIAR and HuR bind to both U-rich and AU-rich RNA in the nanomolar range, with higher overall affinity for U-rich RNA. However, the higher affinity for U–rich sequences is mainly due to faster association with U-rich RNA, which we propose is a reflection of the higher probability of association. Differences between TIAR and HuR are observed in their modes of binding to RNA. TIAR is able to bind deoxy-oligonucleotides with nanomolar affinity, whereas HuR affinity is reduced to a micromolar level. Studies with U-rich DNA reveal that TIAR binding depends less on the 2′-hydroxyl group of RNA than HuR binding. Finally we show that SAXS data, recorded for the first two domains of TIAR in complex with RNA, are more consistent with a flexible, elongated shape and not the compact shape that the first two domains of Hu proteins adopt upon binding to RNA. We thus propose that these triple-RRM proteins, which compete for the same binding sites in cells, interact with their targets in fundamentally different ways.
Collapse
Affiliation(s)
- Henry S Kim
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
TIA1 prevents skipping of a critical exon associated with spinal muscular atrophy. Mol Cell Biol 2010; 31:935-54. [PMID: 21189287 DOI: 10.1128/mcb.00945-10] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Prevention of skipping of exon 7 during pre-mRNA splicing of Survival Motor Neuron 2 (SMN2) holds the promise for cure of spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. Here, we report T-cell-restricted intracellular antigen 1 (TIA1) and TIA1-related (TIAR) proteins as intron-associated positive regulators of SMN2 exon 7 splicing. We show that TIA1/TIAR stimulate exon recognition in an entirely novel context in which intronic U-rich motifs are separated from the 5' splice site by overlapping inhibitory elements. TIA1 and TIAR are modular proteins with three N-terminal RNA recognition motifs (RRMs) and a C-terminal glutamine-rich (Q-rich) domain. Our results reveal that any one RRM in combination with a Q domain is necessary and sufficient for TIA1-associated regulation of SMN2 exon 7 splicing in vivo. We also show that increased expression of TIA1 counteracts the inhibitory effect of polypyrimidine tract binding protein, a ubiquitously expressed factor recently implicated in regulation of SMN exon 7 splicing. Our findings expand the scope of TIA1/TIAR in genome-wide regulation of alternative splicing under normal and pathological conditions.
Collapse
|