1
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Lu J, Ge P, Sawaya MR, Hughes MP, Boyer DR, Cao Q, Abskharon R, Cascio D, Tayeb-Fligelman E, Eisenberg DS. Cryo-EM structures of the D290V mutant of the hnRNPA2 low-complexity domain suggests how D290V affects phase separation and aggregation. J Biol Chem 2024; 300:105531. [PMID: 38072051 PMCID: PMC10844680 DOI: 10.1016/j.jbc.2023.105531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/08/2023] [Accepted: 11/20/2023] [Indexed: 02/02/2024] Open
Abstract
Heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2) is a human ribonucleoprotein that transports RNA to designated locations for translation via its ability to phase separate. Its mutated form, D290V, is implicated in multisystem proteinopathy known to afflict two families, mainly with myopathy and Paget's disease of bone. Here, we investigate this mutant form of hnRNPA2 by determining cryo-EM structures of the recombinant D290V low complexity domain. We find that the mutant form of hnRNPA2 differs from the WT fibrils in four ways. In contrast to the WT fibrils, the PY-nuclear localization signals in the fibril cores of all three mutant polymorphs are less accessible to chaperones. Also, the mutant fibrils are more stable than WT fibrils as judged by phase separation, thermal stability, and energetic calculations. Similar to other pathogenic amyloids, the mutant fibrils are polymorphic. Thus, these structures offer evidence to explain how a D-to-V missense mutation diverts the assembly of reversible, functional amyloid-like fibrils into the assembly of pathogenic amyloid, and may shed light on analogous conversions occurring in other ribonucleoproteins that lead to neurological diseases such as amyotrophic lateral sclerosis and frontotemporal dementia.
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Affiliation(s)
- Jiahui Lu
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Peng Ge
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Michael R Sawaya
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Michael P Hughes
- Department of Cell and Molecular Biology, St Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - David R Boyer
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Qin Cao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Romany Abskharon
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Duilio Cascio
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - Einav Tayeb-Fligelman
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA
| | - David S Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute, Molecular Biology Institute, Howard Hughes Medical Institute, Los Angeles, California, USA.
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2
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Ling X, Yao Y, Ding L, Ma J. The mechanism of UP1 binding and unfolding of human telomeric DNA G-quadruplex. Biochim Biophys Acta Gene Regul Mech 2023; 1866:194985. [PMID: 37717939 DOI: 10.1016/j.bbagrm.2023.194985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/17/2023] [Accepted: 09/11/2023] [Indexed: 09/19/2023]
Abstract
The human telomere contains multiple copies of the DNA sequence d(TTAGGG) which can fold into higher order intramolecular G-quadruplexes and regulate the maintenance of telomere length and chromosomal integrity. The nucleic acid binding protein heteronuclear ribonucleoprotein A1 (hnRNP A1) and its N-terminus proteolytic product UP1 have been shown to efficiently bind and unfold telomeric DNA G-quadruplex. However, the understanding of the molecular mechanism of the UP1 binding and unfolding telomeric G-quadruplexes is still limited. Here, we performed biochemical and biophysical characterizations of UP1 binding and unfolding of human telomeric DNA G-quadruplex d[AGGG(TTAGGG)3], and in combination of systematic site-direct mutagenesis of two tandem RNA recognition motifs (RRMs) in UP1, revealed that RRM1 is responsible for initial binding and unfolding, whereas RRM2 assists RRM1 to complete the unfolding of G-quadruplex. Isothermal titration calorimetry (ITC) and circular dichroism (CD) studies of the interactions between UP1 and DNA G-quadruplex variants indicate that the "TAG" binding motif in Loop2 of telomeric G-quadruplex is critical for UP1 recognition and G-quadruplex unfolding initiation. Together we depict a model for molecular mechanism of hnRNP A1 (UP1) binding and unfolding of the human telomeric DNA G-quadruplex.
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Affiliation(s)
- Xiaobin Ling
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yuqi Yao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Lei Ding
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
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3
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Ryan VH, Perdikari TM, Naik MT, Saueressig CF, Lins J, Dignon GL, Mittal J, Hart AC, Fawzi NL. Tyrosine phosphorylation regulates hnRNPA2 granule protein partitioning and reduces neurodegeneration. EMBO J 2021; 40:e105001. [PMID: 33349959 PMCID: PMC7849316 DOI: 10.15252/embj.2020105001] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 10/14/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
mRNA transport in neurons requires formation of transport granules containing many protein components, and subsequent alterations in phosphorylation status can release transcripts for translation. Further, mutations in a structurally disordered domain of the transport granule protein hnRNPA2 increase its aggregation and cause hereditary proteinopathy of neurons, myocytes, and bone. We examine in vitro hnRNPA2 granule component phase separation, partitioning specificity, assembly/disassembly, and the link to neurodegeneration. Transport granule components hnRNPF and ch-TOG interact weakly with hnRNPA2 yet partition specifically into liquid phase droplets with the low complexity domain (LC) of hnRNPA2, but not FUS LC. In vitro hnRNPA2 tyrosine phosphorylation reduces hnRNPA2 phase separation, prevents partitioning of hnRNPF and ch-TOG into hnRNPA2 LC droplets, and decreases aggregation of hnRNPA2 disease variants. The expression of chimeric hnRNPA2 D290V in Caenorhabditis elegans results in stress-induced glutamatergic neurodegeneration; this neurodegeneration is rescued by loss of tdp-1, suggesting gain-of-function toxicity. The expression of Fyn, a tyrosine kinase that phosphorylates hnRNPA2, reduces neurodegeneration associated with chimeric hnRNPA2 D290V. These data suggest a model where phosphorylation alters LC interaction specificity, aggregation, and toxicity.
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Affiliation(s)
- Veronica H Ryan
- Neuroscience Graduate ProgramBrown UniversityProvidenceRIUSA
| | | | - Mandar T Naik
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
| | | | - Jeremy Lins
- Department of NeuroscienceBrown UniversityProvidenceRIUSA
| | - Gregory L Dignon
- Department of Chemical and Biomolecular EngineeringLehigh UniversityBethlehemPAUSA
| | - Jeetain Mittal
- Department of Chemical and Biomolecular EngineeringLehigh UniversityBethlehemPAUSA
| | - Anne C Hart
- Department of NeuroscienceBrown UniversityProvidenceRIUSA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
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4
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Perdikari TM, Murthy AC, Ryan VH, Watters S, Naik MT, Fawzi NL. SARS-CoV-2 nucleocapsid protein phase-separates with RNA and with human hnRNPs. EMBO J 2020; 39:e106478. [PMID: 33200826 PMCID: PMC7737613 DOI: 10.15252/embj.2020106478] [Citation(s) in RCA: 149] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/31/2022] Open
Abstract
Tightly packed complexes of nucleocapsid protein and genomic RNA form the core of viruses and assemble within viral factories, dynamic compartments formed within the host cells associated with human stress granules. Here, we test the possibility that the multivalent RNA-binding nucleocapsid protein (N) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) condenses with RNA via liquid-liquid phase separation (LLPS) and that N protein can be recruited in phase-separated forms of human RNA-binding proteins associated with SG formation. Robust LLPS with RNA requires two intrinsically disordered regions (IDRs), the N-terminal IDR and central-linker IDR, as well as the folded C-terminal oligomerization domain, while the folded N-terminal domain and the C-terminal IDR are not required. N protein phase separation is induced by addition of non-specific RNA. In addition, N partitions in vitro into phase-separated forms of full-length human hnRNPs (TDP-43, FUS, hnRNPA2) and their low-complexity domains (LCs). These results provide a potential mechanism for the role of N in SARS-CoV-2 viral genome packing and in host-protein co-opting necessary for viral replication and infectivity.
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Affiliation(s)
| | - Anastasia C Murthy
- Molecular BiologyCell Biology & Biochemistry Graduate ProgramBrown UniversityProvidenceRIUSA
| | - Veronica H Ryan
- Neuroscience Graduate ProgramBrown UniversityProvidenceRIUSA
| | - Scott Watters
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
| | - Mandar T Naik
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and BiotechnologyBrown UniversityProvidenceRIUSA
- Robert J. and Nancy D. Carney Institute for Brain ScienceBrown UniversityProvidenceRIUSA
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5
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Chiang WC, Lee MH, Chen TC, Huang JR. Interactions between the Intrinsically Disordered Regions of hnRNP-A2 and TDP-43 Accelerate TDP-43's Conformational Transition. Int J Mol Sci 2020; 21:ijms21165930. [PMID: 32824743 PMCID: PMC7460674 DOI: 10.3390/ijms21165930] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/13/2020] [Accepted: 08/15/2020] [Indexed: 12/28/2022] Open
Abstract
Most biological functions involve protein-protein interactions. Our understanding of these interactions is based mainly on those of structured proteins, because encounters between intrinsically disordered proteins (IDPs) or proteins with intrinsically disordered regions (IDRs) are much less studied, regardless of the fact that more than half eukaryotic proteins contain IDRs. RNA-binding proteins (RBPs) are a large family whose members almost all have IDRs in addition to RNA binding domains. These IDRs, having low sequence similarity, interact, but structural details on these interactions are still lacking. Here, using the IDRs of two RBPs (hnRNA-A2 and TDP-43) as a model, we demonstrate that the rate at which TDP-43's IDR undergoes the neurodegenerative disease related α-helix-to-β-sheet transition increases in relation to the amount of hnRNP-A2's IDR that is present. There are more than 1500 RBPs in human cells and most of them have IDRs. RBPs often join the same complexes to regulate genes. In addition to the structured RNA-recognition motifs, our study demonstrates a general mechanism through which RBPs may regulate each other's functions through their IDRs.
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Affiliation(s)
- Wan-Chin Chiang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan; (W.-C.C.); (M.-H.L.); (T.-C.C.)
| | - Ming-Hsuan Lee
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan; (W.-C.C.); (M.-H.L.); (T.-C.C.)
| | - Tsai-Chen Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan; (W.-C.C.); (M.-H.L.); (T.-C.C.)
| | - Jie-rong Huang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan; (W.-C.C.); (M.-H.L.); (T.-C.C.)
- Institute of Biomedical Informatics, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, No. 155 Section 2, Li-Nong Street, Taipei 11221, Taiwan
- Correspondence:
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6
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Murray DT, Zhou X, Kato M, Xiang S, Tycko R, McKnight SL. Structural characterization of the D290V mutation site in hnRNPA2 low-complexity-domain polymers. Proc Natl Acad Sci U S A 2018; 115:E9782-E9791. [PMID: 30279180 PMCID: PMC6196502 DOI: 10.1073/pnas.1806174115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human genetic studies have given evidence of familial, disease-causing mutations in the analogous amino acid residue shared by three related RNA binding proteins causative of three neurological diseases. Alteration of aspartic acid residue 290 of hnRNPA2 to valine is believed to predispose patients to multisystem proteinopathy. Mutation of aspartic acid 262 of hnRNPA1 to either valine or asparagine has been linked to either amyotrophic lateral sclerosis or multisystem proteinopathy. Mutation of aspartic acid 378 of hnRNPDL to either asparagine or histidine has been associated with limb girdle muscular dystrophy. All three of these aspartic acid residues map to evolutionarily conserved regions of low-complexity (LC) sequence that may function in states of either intrinsic disorder or labile self-association. Here, we present a combination of solid-state NMR spectroscopy with segmental isotope labeling and electron microscopy on the LC domain of the hnRNPA2 protein. We show that, for both the wild-type protein and the aspartic acid 290-to-valine mutant, labile polymers are formed in which the LC domain associates into an in-register cross-β conformation. Aspartic acid 290 is shown to be charged at physiological pH and immobilized within the polymer core. Polymers of the aspartic acid 290-to-valine mutant are thermodynamically more stable than wild-type polymers. These observations give evidence that removal of destabilizing electrostatic interactions may be responsible for the increased propensity of the mutated LC domains to self-associate in disease-causing conformations.
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Affiliation(s)
- Dylan T Murray
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, MD 20892
- Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, Bethesda, MD 20892
| | - Xiaoming Zhou
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Siheng Xiang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, MD 20892;
| | - Steven L McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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7
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Hung CY, Wang YC, Chuang JY, Young MJ, Liaw H, Chang WC, Hung JJ. Nm23-H1-stabilized hnRNPA2/B1 promotes internal ribosomal entry site (IRES)-mediated translation of Sp1 in the lung cancer progression. Sci Rep 2017; 7:9166. [PMID: 28831131 PMCID: PMC5567229 DOI: 10.1038/s41598-017-09558-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/24/2017] [Indexed: 12/20/2022] Open
Abstract
Our recent studies have indicated that specificity protein-1 (Sp1) accumulates substantially in the early stage of lung cancer but is partially decreased in the late stages, which is an important factor in the progression of the cancer. In this study, we found that Nm23-H1 and hnRNPA2/B1 could be recruited to the 5'UTR of Sp1 mRNA. In investigating the clinical relevance of Nm23-H1/Sp1 levels, we found a positive correlation between lung cancer patients with poor prognosis and low levels of Sp1 and Nm23-H1, suggesting an association between Nm23-H1/Sp1 levels and survival rate. Knockdown of Nm23-H1 inhibits lung cancer growth but increases lung cancer cell malignancy, which could be rescued by overexpression of Sp1, indicating that Nm23-H1-induced Sp1 expression is critical for lung cancer progression. We also found that Nm23-H1 increases the protein stability of hnRNPA2/B1and is thereby co-recruited to the 5'UTR of Sp1 mRNA to regulate cap-independent translational activity. Since the Sp1 level is tightly regulated during lung cancer progression, understanding the molecular mechanisms underlying the regulation by Nm23-H1/hnRNPA2B1 of Sp1 expression in the various stages of lung cancer will be beneficial for lung cancer therapy in the future.
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Affiliation(s)
- Chia-Yang Hung
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yi-Chang Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jian-Ying Chuang
- The PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Ming-Jer Young
- Department of Biotechnology and Bioindustry Science, National Cheng Kung University, Tainan, Taiwan
- Center for Infection Disease and Signal Transduction, National Cheng Kung University, Tainan, Taiwan
| | - Hungjiun Liaw
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Chang Chang
- The PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Jan-Jong Hung
- Department of Biotechnology and Bioindustry Science, National Cheng Kung University, Tainan, Taiwan.
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
- Center for Infection Disease and Signal Transduction, National Cheng Kung University, Tainan, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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8
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Krebs BB, De Mesquita JF. Amyotrophic Lateral Sclerosis Type 20 - In Silico Analysis and Molecular Dynamics Simulation of hnRNPA1. PLoS One 2016; 11:e0158939. [PMID: 27414033 PMCID: PMC4945010 DOI: 10.1371/journal.pone.0158939] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/24/2016] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that affects the upper and lower motor neurons. 5-10% of cases are genetically inherited, including ALS type 20, which is caused by mutations in the hnRNPA1 gene. The goals of this work are to analyze the effects of non-synonymous single nucleotide polymorphisms (nsSNPs) on hnRNPA1 protein function, to model the complete tridimensional structure of the protein using computational methods and to assess structural and functional differences between the wild type and its variants through Molecular Dynamics simulations. nsSNP, PhD-SNP, Polyphen2, SIFT, SNAP, SNPs&GO, SNPeffect and PROVEAN were used to predict the functional effects of nsSNPs. Ab initio modeling of hnRNPA1 was made using Rosetta and refined using KoBaMIN. The structure was validated by PROCHECK, Rampage, ERRAT, Verify3D, ProSA and Qmean. TM-align was used for the structural alignment. FoldIndex, DICHOT, ELM, D2P2, Disopred and DisEMBL were used to predict disordered regions within the protein. Amino acid conservation analysis was assessed by Consurf, and the molecular dynamics simulations were performed using GROMACS. Mutations D314V and D314N were predicted to increase amyloid propensity, and predicted as deleterious by at least three algorithms, while mutation N73S was predicted as neutral by all the algorithms. D314N and D314V occur in a highly conserved amino acid. The Molecular Dynamics results indicate that all mutations increase protein stability when compared to the wild type. Mutants D314N and N319S showed higher overall dimensions and accessible surface when compared to the wild type. The flexibility level of the C-terminal residues of hnRNPA1 is affected by all mutations, which may affect protein function, especially regarding the protein ability to interact with other proteins.
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Affiliation(s)
- Bruna Baumgarten Krebs
- Laboratory of Bioinformatics and Computational Biology, Department of Genetics and Molecular Biology, Federal University of Rio de Janeiro State (UNIRIO), Rio de Janeiro, Brazil
| | - Joelma Freire De Mesquita
- Laboratory of Bioinformatics and Computational Biology, Department of Genetics and Molecular Biology, Federal University of Rio de Janeiro State (UNIRIO), Rio de Janeiro, Brazil
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9
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Jean-Philippe J, Paz S, Caputi M. hnRNP A1: the Swiss army knife of gene expression. Int J Mol Sci 2013; 14:18999-9024. [PMID: 24065100 PMCID: PMC3794818 DOI: 10.3390/ijms140918999] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic cells express a large variety of RNA binding proteins (RBPs), with diverse affinities and specificities towards target RNAs. These proteins play a crucial role in almost every aspect of RNA biogenesis, expression and function. The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a complex and diverse family of RNA binding proteins. hnRNPs display multiple functions in the processing of heterogeneous nuclear RNAs into mature messenger RNAs. hnRNP A1 is one of the most abundant and ubiquitously expressed members of this protein family. hnRNP A1 plays multiple roles in gene expression by regulating major steps in the processing of nascent RNA transcripts. The transcription, splicing, stability, export through nuclear pores and translation of cellular and viral transcripts are all mechanisms modulated by this protein. The diverse functions played by hnRNP A1 are not limited to mRNA biogenesis, but extend to the processing of microRNAs, telomere maintenance and the regulation of transcription factor activity. Genomic approaches have recently uncovered the extent of hnRNP A1 roles in the development and differentiation of living organisms. The aim of this review is to highlight recent developments in the study of this protein and to describe its functions in cellular and viral gene expression and its role in human pathologies.
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Affiliation(s)
- Jacques Jean-Philippe
- Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Rd, Boca Raton, FL 33431, USA.
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10
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Kim HJ, Kim NC, Wang YD, Scarborough EA, Moore J, Diaz Z, MacLea KS, Freibaum B, Li S, Molliex A, Kanagaraj AP, Carter R, Boylan KB, Wojtas AM, Rademakers R, Pinkus JL, Greenberg SA, Trojanowski JQ, Traynor BJ, Smith BN, Topp S, Gkazi AS, Miller J, Shaw CE, Kottlors M, Kirschner J, Pestronk A, Li YR, Ford AF, Gitler AD, Benatar M, King OD, Kimonis VE, Ross ED, Weihl CC, Shorter J, Taylor JP. Mutations in prion-like domains in hnRNPA2B1 and hnRNPA1 cause multisystem proteinopathy and ALS. Nature 2013; 495:467-73. [PMID: 23455423 PMCID: PMC3756911 DOI: 10.1038/nature11922] [Citation(s) in RCA: 1067] [Impact Index Per Article: 97.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/17/2013] [Indexed: 01/18/2023]
Abstract
Algorithms designed to identify canonical yeast prions predict that around 250 human proteins, including several RNA-binding proteins associated with neurodegenerative disease, harbour a distinctive prion-like domain (PrLD) enriched in uncharged polar amino acids and glycine. PrLDs in RNA-binding proteins are essential for the assembly of ribonucleoprotein granules. However, the interplay between human PrLD function and disease is not understood. Here we define pathogenic mutations in PrLDs of heterogeneous nuclear ribonucleoproteins (hnRNPs) A2B1 and A1 in families with inherited degeneration affecting muscle, brain, motor neuron and bone, and in one case of familial amyotrophic lateral sclerosis. Wild-type hnRNPA2 (the most abundant isoform of hnRNPA2B1) and hnRNPA1 show an intrinsic tendency to assemble into self-seeding fibrils, which is exacerbated by the disease mutations. Indeed, the pathogenic mutations strengthen a 'steric zipper' motif in the PrLD, which accelerates the formation of self-seeding fibrils that cross-seed polymerization of wild-type hnRNP. Notably, the disease mutations promote excess incorporation of hnRNPA2 and hnRNPA1 into stress granules and drive the formation of cytoplasmic inclusions in animal models that recapitulate the human pathology. Thus, dysregulated polymerization caused by a potent mutant steric zipper motif in a PrLD can initiate degenerative disease. Related proteins with PrLDs should therefore be considered candidates for initiating and perhaps propagating proteinopathies of muscle, brain, motor neuron and bone.
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Affiliation(s)
- Hong Joo Kim
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Nam Chul Kim
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Yong-Dong Wang
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Emily A. Scarborough
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer Moore
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Zamia Diaz
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyle S. MacLea
- Department of Biochemistry and Molecular Biology, Colorado State University; Fort Collins, CO 80523, USA
| | - Brian Freibaum
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Songqing Li
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Amandine Molliex
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Anderson P. Kanagaraj
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Robert Carter
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
| | - Kevin B. Boylan
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Jack L. Pinkus
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Steven A. Greenberg
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - John Q. Trojanowski
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Bryan J. Traynor
- Neuromuscular Diseases Research Group, Laboratory of Neurogenetics, Porter Neuroscience Building, NIA, NIH, Bethesda, MD 20892, USA
| | - Bradley N. Smith
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Simon Topp
- King’s College London Centre for Neurodegeneration Research, Department of Clinical Neuroscience, Institute of Psychiatry, London SE5 8AF, UK
| | - Athina-Soragia Gkazi
- King’s College London Centre for Neurodegeneration Research, Department of Clinical Neuroscience, Institute of Psychiatry, London SE5 8AF, UK
| | - Jack Miller
- King’s College London Centre for Neurodegeneration Research, Department of Clinical Neuroscience, Institute of Psychiatry, London SE5 8AF, UK
| | - Christopher E. Shaw
- King’s College London Centre for Neurodegeneration Research, Department of Clinical Neuroscience, Institute of Psychiatry, London SE5 8AF, UK
| | - Michael Kottlors
- Division of Neuropediatrics and Muscle Disorders, University Children's Hospital Freiburg, Freiburg, Germany
| | - Janbernd Kirschner
- Division of Neuropediatrics and Muscle Disorders, University Children's Hospital Freiburg, Freiburg, Germany
| | - Alan Pestronk
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Yun R. Li
- Medical Scientist Training Program, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alice Flynn Ford
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aaron D. Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael Benatar
- Neurology Department, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Oliver D. King
- Boston Biomedical Research Institute, Watertown, MA 02472, USA
| | - Virginia E. Kimonis
- Department of Pediatrics, Division of Genetics and Metabolism, University of California-Irvine, 2501 Hewitt Hall, Irvine, CA, 92696, USA
| | - Eric D. Ross
- Department of Biochemistry and Molecular Biology, Colorado State University; Fort Collins, CO 80523, USA
| | - Conrad C. Weihl
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - J. Paul Taylor
- Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38120, USA
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11
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Barraud P, Allain FHT. Solution structure of the two RNA recognition motifs of hnRNP A1 using segmental isotope labeling: how the relative orientation between RRMs influences the nucleic acid binding topology. J Biomol NMR 2013; 55:119-38. [PMID: 23247503 DOI: 10.1007/s10858-012-9696-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/11/2012] [Indexed: 05/21/2023]
Abstract
Human hnRNP A1 is a multi-functional protein involved in many aspects of nucleic-acid processing such as alternative splicing, micro-RNA biogenesis, nucleo-cytoplasmic mRNA transport and telomere biogenesis and maintenance. The N-terminal region of hnRNP A1, also named unwinding protein 1 (UP1), is composed of two closely related RNA recognition motifs (RRM), and is followed by a C-terminal glycine rich region. Although crystal structures of UP1 revealed inter-domain interactions between RRM1 and RRM2 in both the free and bound form of UP1, these interactions have never been established in solution. Moreover, the relative orientation of hnRNP A1 RRMs is different in the free and bound crystal structures of UP1, raising the question of the biological significance of this domain movement. In the present study, we have used NMR spectroscopy in combination with segmental isotope labeling techniques to carefully analyze the inter-RRM contacts present in solution and subsequently determine the structure of UP1 in solution. Our data unambiguously demonstrate that hnRNP A1 RRMs interact in solution, and surprisingly, the relative orientation of the two RRMs observed in solution is different from the one found in the crystal structure of free UP1 and rather resembles the one observed in the nucleic-acid bound form of the protein. This strongly supports the idea that the two RRMs of hnRNP A1 have a single defined relative orientation which is the conformation previously observed in the bound form and now observed in solution using NMR. It is likely that the conformation in the crystal structure of the free form is a less stable form induced by crystal contacts. Importantly, the relative orientation of the RRMs in proteins containing multiple-RRMs strongly influences the RNA binding topologies that are practically accessible to these proteins. Indeed, RRM domains are asymmetric binding platforms contacting single-stranded nucleic acids in a single defined orientation. Therefore, the path of the nucleic acid molecule on the multiple RRM domains is strongly dependent on whether the RRMs are interacting with each other. The different nucleic acid recognition modes by multiple-RRM domains are briefly reviewed and analyzed on the basis of the current structural information.
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Affiliation(s)
- Pierre Barraud
- Institute of Molecular Biology and Biophysics, ETH Zurich, Schafmattstrasse 20, 8093 Zurich, Switzerland
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12
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Nakamura RL, Landt SG, Mai E, Nejim J, Chen L, Frankel AD. A cell-based method for screening RNA-protein interactions: identification of constitutive transport element-interacting proteins. PLoS One 2012; 7:e48194. [PMID: 23133567 PMCID: PMC3485056 DOI: 10.1371/journal.pone.0048194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 09/24/2012] [Indexed: 12/21/2022] Open
Abstract
We have developed a mammalian cell-based screening platform to identify proteins that assemble into RNA-protein complexes. Based on Tat-mediated activation of the HIV LTR, proteins that interact with an RNA target elicit expression of a GFP reporter and are captured by fluorescence activated cell sorting. This "Tat-hybrid" screening platform was used to identify proteins that interact with the Mason Pfizer monkey virus (MPMV) constitutive transport element (CTE), a structured RNA hairpin that mediates the transport of unspliced viral mRNAs from the nucleus to the cytoplasm. Several hnRNP-like proteins, including hnRNP A1, were identified and shown to interact with the CTE with selectivity in the reporter system comparable to Tap, a known CTE-binding protein. In vitro gel shift and pull-down assays showed that hnRNP A1 is able to form a complex with the CTE and Tap and that the RGG domain of hnRNP A1 mediates binding to Tap. These results suggest that hnRNP-like proteins may be part of larger export-competent RNA-protein complexes and that the RGG domains of these proteins play an important role in directing these binding events. The results also demonstrate the utility of the screening platform for identifying and characterizing new components of RNA-protein complexes.
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Affiliation(s)
- Robert L. Nakamura
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Stephen G. Landt
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Emily Mai
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Jemiel Nejim
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
| | - Lily Chen
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Alan D. Frankel
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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13
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El-Kased RF, Koy C, Deierling T, Lorenz P, Qian Z, Li Y, Thiesen HJ, Glocker MO. Mass spectrometric and peptide chip epitope mapping of rheumatoid arthritis autoantigen RA33. Eur J Mass Spectrom (Chichester) 2009; 15:747-759. [PMID: 19940341 DOI: 10.1255/ejms.1040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The protein termed RA33 was determined to be one major autoantigen in rheumatoid arthritis (RA) patients and antiRA33 auto-antibodies were found to appear shortly after onset of RA. They are often detectable before a final diagnosis can be made in the clinic. The aim of our study is to characterise the epitope of a monoclonal antiRA33 antibody on recombinant RA33 using mass spectrometric epitope mapping. Recombinant RA33 has been subjected to BrCN cleavage and fragments were separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Subsequent in-gel proteolytic digestion and mass spectrometric analysis determined the partial sequences in the protein bands. Western blotting of SDS-PAGE-separated protein fragments revealed immuno-positive, i.e. epitope-containing bands. BrCN-derived RA33 fragments were also separated by high- performance liquid chromatography (HPLC) and immuno-reactivity of peptides was measured by dot-blot analysis with the individual HPLC fractions after partial amino acid sequences were determined. The epitope region identified herewith was compared to data from peptide chip analysis with 15-meric synthetic peptides attached to a glass surface. Results from all three analyses consistently showed that the epitope of the monoclonal antiRA33 antibody is located in the aa79-84 region on recombinant RA33; the epitope sequence is MAARPHSIDGRVVEP. Sequence comparisons of the 15 best scoring peptides from the peptide chip analysis revealed that the epitope can be separated into two adjacent binding parts. The N-terminal binding parts comprise the amino acid residues "DGR", resembling the general physico-chemical properties "acidic/polar-small-basic". The C-terminal binding parts contain the amino acid residues "VVE", with the motif "hydrophobic-gap-acidic". The matching epitope region that emerged from our analysis on both the full-length protein and the 15-meric surface bound peptides suggests that peptide chips are indeed suitable tools for screening patterns of autoantibodies in patients suffering from autoimmune diseases.
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Affiliation(s)
- R F El-Kased
- Proteome Center Rostock, University of Rostock, Schillingallee 69, 18057 Rostock, Germany
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14
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Guil S, Cáceres JF. The multifunctional RNA-binding protein hnRNP A1 is required for processing of miR-18a. Nat Struct Mol Biol 2007; 14:591-6. [PMID: 17558416 DOI: 10.1038/nsmb1250] [Citation(s) in RCA: 418] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 04/09/2007] [Indexed: 12/19/2022]
Abstract
hnRNP A1 is an RNA-binding protein involved in various aspects of RNA processing. Use of an in vivo cross-linking and immunoprecipitation protocol to find hnRNP A1 RNA targets resulted in the identification of a microRNA (miRNA) precursor, pre-miR-18a. This microRNA is expressed as part of a cluster of intronic RNAs, including miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1 and miR-92, and potentially acts as an oncogene. Here we show that hnRNP A1 binds specifically to the primary RNA sequence pri-miR-18a before Drosha processing. HeLa cells depleted of hnRNP A1 have reduced in vitro processing activity with pri-miR-18a and also show reduced abundances of endogenous pre-miR-18a. Furthermore, we show that hnRNP A1 is required for miR-18a-mediated repression of a target reporter in vivo. These results underscore a previously uncharacterized role for general RNA-binding proteins as auxiliary factors that facilitate the processing of specific miRNAs.
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Affiliation(s)
- Sonia Guil
- Medical Research Council Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, Scotland, UK
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15
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Tanaka E, Fukuda H, Nakashima K, Tsuchiya N, Seimiya H, Nakagama H. HnRNP A3 binds to and protects mammalian telomeric repeats in vitro. Biochem Biophys Res Commun 2007; 358:608-14. [PMID: 17502110 DOI: 10.1016/j.bbrc.2007.04.177] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Accepted: 04/30/2007] [Indexed: 11/28/2022]
Abstract
The biological function of hnRNP family proteins is widely diverse and involved in pre-mRNA processing, transcriptional regulation, recombination, and telomere maintenance. In the course of our study on the elucidation of biological functions of minisatellite DNA, we isolated several nuclear proteins that bind to the mouse minisatellite Pc-1, which consists of a tandem array of d(GGCAG) repeats, from NIH3T3 cells. One of the minisatellite binding proteins, MNBP-A, which binds to a single-stranded G-rich strand of the Pc-1 repeat, was proven identical to the hnRNP A3. Recombinant hnRNP A3 was demonstrated to bind to the single-stranded telomeric d(TTAGGG) repeat with much higher affinity than the d(GGCAG) repeat. Binding of hnRNP A3 to the single-stranded telomeric repeat protected the repeat from nuclease attack, and inhibited both telomerase reaction and DNA synthesis in vitro. These results suggest a possible biological role of hnRNP A3 in the stable maintenance of telomere repeats.
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Affiliation(s)
- Etsuko Tanaka
- Biochemistry Division, National Cancer Center Research Institute, Tsukiji 5, Tokyo, Japan
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16
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Hallay H, Locker N, Ayadi L, Ropers D, Guittet E, Branlant C. Biochemical and NMR Study on the Competition between Proteins SC35, SRp40, and Heterogeneous Nuclear Ribonucleoprotein A1 at the HIV-1 Tat Exon 2 Splicing Site. J Biol Chem 2006; 281:37159-74. [PMID: 16990281 DOI: 10.1074/jbc.m603864200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human immunodeficiency virus, type 1, Tat protein plays a key role in virus multiplication. Because of its apoptotic property, its production is highly controlled. It depends upon the A3 splicing site utilization. A key control of site A3 activity is the ESS2 splicing silencer, which is located within the long stem-loop structure 3 (SLS3), far downstream from site A3. Here, by enzymatic footprints, we demonstrate the presence of several heterogeneous nuclear ribonucleoprotein (hnRNP) A1-binding sites on SLS3 and show the importance of the C-terminal Gly domain of hnRNP A1 in the formation of stable complexes containing several hnRNP A1 molecules bound on SLS3. Mutations in each of the UAG triplets in ESS2 strongly reduce the overall hnRNP A1 binding, showing the central role of ESS2 in hnRNP A1 assembly on SLS2-SLS3. Using NMR spectroscopy, we demonstrate the direct interaction of ESS2 with the RNA recognition motifs domains of hnRNP A1. This interaction has limited effect on the RNA two-dimensional structure. The SR proteins SC35 and SRp40 were found previously to be strong activators of site A3 utilization. By enzymatic and chemical footprints, we delineate their respective binding sites on SLS2 and SLS3 and find a strong similarity between the hnRNP A1-, SC35-, and SRp40-binding sites. The strongest SC35-binding site only has a modest contribution to site A3 activation. Hence, the main role of SR proteins at site A3 is to counteract hnRNP A1 binding on ESS2 and ESE2. Indeed, we found that ESE2 has inhibitory properties because of its ability to bind hnRNP A1.
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Affiliation(s)
- Houda Hallay
- UMR 7567 CNRS-Université Henri Poincaré-Nancy I, Boulevard des Aiguillettes, BP239, 54506 Vandoeuvre-lès-Nancy Cedex and Laboratoire de Chimie et Biologie Structurales, ICSN-CNRS, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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17
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Griffith BN, Walsh CM, Szeszel-Fedorowicz W, Timperman AT, Salati LM. Identification of hnRNPs K, L and A2/B1 as candidate proteins involved in the nutritional regulation of mRNA splicing. ACTA ACUST UNITED AC 2006; 1759:552-61. [PMID: 17095106 PMCID: PMC1828878 DOI: 10.1016/j.bbaexp.2006.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 09/27/2006] [Accepted: 10/03/2006] [Indexed: 11/24/2022]
Abstract
Nutrient regulation of glucose-6-phosphate dehydrogenase (G6PD) expression occurs through changes in the rate of splicing of G6PD pre-mRNA. This posttranscriptional mechanism accounts for the 12- to 15-fold increase in G6PD expression in livers of mice that were starved and then refed a high-carbohydrate diet. Regulation of G6PD pre-mRNA splicing requires a cis-acting element in exon 12 of the pre-mRNA. Using RNA probes to exon 12 and nuclear extracts from livers of mice that were starved or refed, proteins of 60 kDa and 37 kDa were detected bound to nucleotides 65-79 of exon 12 and this binding was decreased by 50% with nuclear extracts from refed mice. The proteins were identified as hnRNPs K, L, and A2/B1 by LC-MS/MS. The decrease in binding of these proteins to exon 12 during refeeding was not accompanied by a decrease in the total amount of these proteins in total nuclear extract. HnRNPs K, L and A2/B1 have known roles in the regulation of mRNA splicing. The decrease in binding of these proteins during treatments that increase G6PD expression is consistent with a role for these proteins in the inhibition of G6PD mRNA splicing.
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Affiliation(s)
- Brian N. Griffith
- Department of Biochemistry and Molecular Pharmacology, West Virginia University, Morgantown, WV 26506
| | - Callee M. Walsh
- Department of Biochemistry and Molecular Pharmacology, West Virginia University, Morgantown, WV 26506
| | | | | | - Lisa M. Salati
- Department of Biochemistry and Molecular Pharmacology, West Virginia University, Morgantown, WV 26506
- To whom correspondence should be addressed: Department of Biochemistry and Molecular Pharmacology, WVU Health Sciences Center, PO Box 9142, Morgantown, WV 26506, Phone: (304) 293-7759, e-mail
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18
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Abstract
Heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a multitasking protein involved in RNA packaging, alternative splicing of pre-mRNA, telomere maintenance, cytoplasmic RNA trafficking, and translation. It binds short segments of single-stranded nucleic acids, including the A2RE11 RNA element that is necessary and sufficient for cytoplasmic transport of a subset of mRNAs in oligodendrocytes and neurons. We have explored the structures of hnRNP A2, its RNA recognition motifs (RRMs) and Gly-rich module, and the RRM complexes with A2RE11. Circular dichroism spectroscopy showed that the secondary structure of the first 189 residues of hnRNP A2 parallels that of the tandem betaalpha betabeta alphabeta RRMs of its paralogue, hnRNP A1, previously deduced from X-ray diffraction studies. The unusual GRD was shown to have substantial beta-sheet and beta-turn structure. Sedimentation equilibrium and circular dichroism results were consistent with the tandem RRM region being monomeric and supported earlier evidence for the binding of two A2RE11 oligoribonucleotides to this domain, in contrast to the protein dimer formed by the complex of hnRNP A1 with the telomeric ssDNA repeat. A three-dimensional structure for the N-terminal, two-RRM-containing segment of hnRNP A2 was derived by homology modeling. This structure was used to derive a model for the complex with A2RE11 using the previously described interaction of pairs of stacked nucleotides with aromatic residues on the RRM beta-sheet platforms, conserved in other RRM-RNA complexes, together with biochemical data and molecular dynamics-based observations of inter-RRM mobility.
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Affiliation(s)
- Michael J Landsberg
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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19
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Lee SM, Dunnavant FD, Jang H, Zunt J, Levin MC. Autoantibodies that recognize functional domains of hnRNPA1 implicate molecular mimicry in the pathogenesis of neurological disease. Neurosci Lett 2006; 401:188-93. [PMID: 16600502 PMCID: PMC2882438 DOI: 10.1016/j.neulet.2006.03.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/27/2006] [Accepted: 03/08/2006] [Indexed: 11/25/2022]
Abstract
As a model for molecular mimicry in neurological disease, we study people infected with human T-lymphotropic virus type 1 (HTLV-1) who develop HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), an immune-mediated disease of the central nervous system (CNS). In HAM/TSP, data suggests molecular mimicry is the result of cross-reactive antibodies between HTLV-1-tax and heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), a protein over-expressed in human CNS neurons. The hnRNP A1 epitope recognized by autoantibodies was unknown. In this study, we hypothesized that antibodies purified from HAM/TSP patients would react with functionally significant domains of hnRNP A1. Western blotting of functionally significant deletion mutants and overlapping fusion proteins using HAM/TSP IgG revealed two core epitopes within the C-terminal region of hnRNP A1. The first (aminoacids 191-SSQRGRSGSGNF-202), overlapped the RGG domain and the second (aminoacids 293-GQYFAKPRNQGG-304), with the M9 shuttling sequence, two functionally important regions of hnRNP A1. Monoclonal antibodies to HTLV-1-tax also reacted with the epitopes. These data fulfill an important criterion of molecular mimicry, namely that mimicking epitopes are not random, but include biologically significant regions of target proteins. This suggests an important role for the cross-reactive immune response between HTLV-1 and hnRNP A1 in the pathogenesis of immune-mediated neurological diseases via molecular mimicry.
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Affiliation(s)
- Sang Min Lee
- Research Service, Veterans Affairs Medical Center, Memphis, TN, USA
- Department of Neurology, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Center for the Neurobiology of Brain Diseases, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Floyd D. Dunnavant
- Research Service, Veterans Affairs Medical Center, Memphis, TN, USA
- Department of Neurology, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Haeman Jang
- Research Service, Veterans Affairs Medical Center, Memphis, TN, USA
- Department of Neurology, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Center for the Neurobiology of Brain Diseases, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Joseph Zunt
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Michael C. Levin
- Research Service, Veterans Affairs Medical Center, Memphis, TN, USA
- Department of Neurology, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Center for the Neurobiology of Brain Diseases, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Department of Anatomy and Neurobiology, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Center of Excellence in Connective Tissue Diseases, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Corresponding author at: Department of Neurology, University of Tennessee Health Sciences Center, Link Building, Room 415, 855 Monroe Avenue, Memphis, TN 38163, USA. Tel.: +1 901 448 2243; fax: +1 901 448 7440. (M.C. Levin)
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20
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Iijima M, Suzuki M, Tanabe A, Nishimura A, Yamada M. Two motifs essential for nuclear import of the hnRNP A1 nucleocytoplasmic shuttling sequence M9 core. FEBS Lett 2006; 580:1365-70. [PMID: 16455081 DOI: 10.1016/j.febslet.2006.01.058] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 12/31/2005] [Accepted: 01/04/2006] [Indexed: 10/25/2022]
Abstract
Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 regulates mRNA genesis. It shuttles between the nucleus and cytoplasm. Its shuttling signal is a 38-residue sequence M9. We studied the nuclear import and export of M9 by mutational analysis. Heterokaryon assay indicated that the 19-residue sequence SNFGPMKGGNFGGRSSGPY (M9 core) is necessary and sufficient for shuttling. Moreover, M9 core mutation revealed that in addition to the hitherto characterized N-terminal motif SNFGPMK, the C-terminal motif PY is crucial for nuclear import as well as for binding to transportin. Key residues of the motifs are conserved in the shuttling signals of hnRNP D and JKTBP.
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Affiliation(s)
- Megumi Iijima
- Graduate School of Integrated Science, Yokohama City University, 22-2, Seto, Kanazawa-ku, Yokohama 236-0027, Japan
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21
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Lee CH, Lum JHK, Cheung BPY, Wong MS, Butt YKC, Tam MF, Chan WY, Chow C, Hui PK, Kwok FSL, Lo SCL, Fan DM. Identification of the heterogeneous nuclear ribonucleoprotein A2/B1 as the antigen for the gastrointestinal cancer specific monoclonal antibody MG7. Proteomics 2005; 5:1160-6. [PMID: 15759317 DOI: 10.1002/pmic.200401159] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
MG7 is an early gastrointestinal cancer specific monoclonal antibody. It can detect gastric cancer with high sensitivity and specificity. However, the target antigen for MG7 has not been identified. Western blot analysis revealed that the MG7 antibody reproducibly recognized two approximately 35 kDa proteins in the total cell lysates of human gastric carcinoma cell lines KATO III and MKN-45. Using a proteomic approach, we identified these MG7 immunoreactive proteins as the human heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1). Western blot analysis of nuclear and cytosolic fraction of KATO III cells using either MG7 or hnRNP A2/B1 antibodies confirmed that the target antigen is located exclusively in the nucleus. With the use of archival samples, we also found that the level of hnRNP A2/B1 protein was increased in gastric cancer tissues (4 out of 5 patients), when compared to their corresponding matching normal stomach tissue.
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MESH Headings
- Adult
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/metabolism
- Antibodies, Neoplasm/chemistry
- Antigens, Neoplasm/chemistry
- Blotting, Western
- Cell Line, Tumor
- Cell Nucleus/metabolism
- Cytosol/metabolism
- Databases, Protein
- Electrophoresis, Polyacrylamide Gel
- Female
- Gastric Mucosa/metabolism
- Gastrointestinal Neoplasms/immunology
- Gastrointestinal Neoplasms/metabolism
- Gene Expression Regulation, Neoplastic
- Heterogeneous-Nuclear Ribonucleoprotein Group A-B/biosynthesis
- Heterogeneous-Nuclear Ribonucleoprotein Group A-B/chemistry
- Humans
- Male
- Middle Aged
- Peptides/chemistry
- Polymerase Chain Reaction
- Proteomics/methods
- Software
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Up-Regulation
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Affiliation(s)
- Chi-ho Lee
- The Proteomic Task Force, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
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Luo H, Chen Q, Chen J, Chen K, Shen X, Jiang H. The nucleocapsid protein of SARS coronavirus has a high binding affinity to the human cellular heterogeneous nuclear ribonucleoprotein A1. FEBS Lett 2005; 579:2623-8. [PMID: 15862300 PMCID: PMC7094256 DOI: 10.1016/j.febslet.2005.03.080] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 01/25/2005] [Accepted: 03/07/2005] [Indexed: 01/29/2023]
Abstract
The nucleocapsid (N) protein of SARS coronavirus (SARS_CoV) is a major structural component of virions, which appears to be a multifunctional protein involved in viral RNA replication and translation. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is related to the pre‐mRNA splicing in the nucleus and translation regulation in the cytoplasm. In this report, based on the relevant biophysical and biochemical assays, the nucleocapsid protein of SARS_CoV (SARS_N) was discovered to exhibit high binding affinity to human hnRNP A1. GST pull‐down results clearly demonstrated that SARS_N protein could directly and specifically bind to human hnRNP A1 in vitro. Yeast two‐hybrid assays further indicated in vivo that such binding relates to the fragment (aa 161–210) of SARS_N and the Gly‐rich domain (aa 203–320) of hnRNP A1. Moreover, kinetic analyses by surface plasmon resonance (SPR) technology revealed that SARS_N protein has a specific binding affinity against human hnRNP A1 with KD at 0.35 ± 0.02 μM (kon
= 5.83 ± 0.42 × 103
M−1
s−1 and koff
= 2.06 ± 0.12 × 10−3
s−1). It is suggested that both SARS_N and hnRNP A1 proteins are possibly within the SARS_CoV replication/transcription complex and SARS_N/human hnRNP A1 interaction might function in the regulation of SARS_CoV RNA synthesis. In addition, the determined results showed that SARS_N protein has only one binding domain for interacting with human hnRNP A1, which is different from the mouse hepatitis virus (MHV) binding case where the nucleocapsid protein of MHV (MHV_N) was found to have two binding domains involved in the MHV_N/hnRNP A1 interaction, thereby suggesting that SARS_N protein might carry out a different binding mode to bind to human hnRNP A1 for its further function performance in comparison with MHV_N.
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Affiliation(s)
- Haibin Luo
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
| | - Qing Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jing Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
| | - Kaixian Chen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xu Shen
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Hualiang Jiang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 201203, China
- School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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23
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Allemand E, Guil S, Myers M, Moscat J, Cáceres JF, Krainer AR. Regulation of heterogenous nuclear ribonucleoprotein A1 transport by phosphorylation in cells stressed by osmotic shock. Proc Natl Acad Sci U S A 2005; 102:3605-10. [PMID: 15738418 PMCID: PMC553333 DOI: 10.1073/pnas.0409889102] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 is an alternative splicing factor that is mainly nuclear, although it shuttles rapidly between nuclear and cytoplasmic compartments. Cells stressed by osmotic shock (OSM) activate the mitogen-activated protein kinase kinase(3/6)-p38 signaling pathway, which in turn results in accumulation of hnRNP A1 in the cytoplasm. This effect modulates alternative splicing regulation in vivo and correlates with increased hnRNP A1 phosphorylation. We have characterized the molecular mechanism involved in the cytoplasmic accumulation of hnRNP A1 in NIH 3T3 cells subjected to OSM. This treatment results in serine-specific phosphorylation within a C-terminal peptide, dubbed the "F-peptide," which is adjacent to the M9 motif that mediates bidirectional transport of hnRNP A1. Analysis of mutants in which the F-peptide serines were replaced by aspartic acids or alanines showed that F-peptide phosphorylation is required for the subcellular redistribution of hnRNP A1 in cells subjected to OSM. Furthermore, F-peptide phosphorylation modulates the interaction of hnRNP A1 with transportin Trn1. Our findings suggest that the phosphorylation of F-peptide by cell-signaling pathways regulates the rate of hnRNP A1 nuclear import.
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Affiliation(s)
- Eric Allemand
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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24
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Abstract
Earlier studies showed that HepG2 cells stably transfected with any one fibrinogen chain cDNA enhanced the expression of the other two fibrinogen chains. In this report, a regulatory element "TGCTCTC" in the gamma-fibrinogen promoter region, -322 to -316, is identified, which is involved in increased expression of gamma chain in HepG2 cells that are transfected with Bbeta fibrinogen cDNA. By electrophoretic mobility shift assay, three DNA-protein complexes were found to form with the regulatory element. The amount of the protein complexes that bind with the regulatory element was much reduced in HepG2 cells transfected with Bbeta cDNA. By DNA-affinity chromatography, mass spectrometry, and supershift assay, human heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) was identified as a component of the complexes. Overexpression of hnRNP A1 suppressed basal gamma-fibrinogen transcription. These results indicate that the basal expression of gamma-fibrinogen is regulated by a constitutive transcriptional repressor protein, hnRNP A1, and the decreased binding activity of hnRNP A1 leads to the overexpression of gamma chain in HepG2 cells that overexpress the Bbeta chain.
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Affiliation(s)
- Hui Xia
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York 10021, USA.
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25
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Abstract
The heterogeneous nuclear ribonucleoprotein (hnRNP) A2 is a multi-tasking protein that acts in the cytoplasm and nucleus. We have explored the possibility that this protein is associated with telomeres and participates in their maintenance. Rat brain hnRNP A2 was shown to have two nucleic acid binding sites. In the presence of heparin one site binds single-stranded oligodeoxyribonucleotides irrespective of sequence but not the corresponding oligoribonucleotides. Both the hnRNP A2-binding cis-acting element for the cytoplasmic RNA trafficking element, A2RE, and the ssDNA telomere repeat match a consensus sequence for binding to a second sequence-specific site identified by mutational analysis. hnRNP A2 protected the telomeric repeat sequence, but not the complementary sequence, against DNase digestion: the glycine-rich domain was found to be necessary, but not sufficient, for protection. The N-terminal RRM (RNA recognition motif) and tandem RRMs of hnRNP A2 also bind the single-stranded, template-containing segment of telomerase RNA. hnRNP A2 colocalizes with telomeric chromatin in the subset of PML bodies that are a hallmark of ALT cells, reinforcing the evidence for hnRNPs having a role in telomere maintenance. Our results support a model in which hnRNP A2 acts as a molecular adapter between single-stranded telomeric repeats, or telomerase RNA, and another segment of ssDNA.
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Affiliation(s)
| | - Lyndal Wayman
- Children's Medical Research Institute214 Hawkesbury Road, Westmead, NSW 2145, Australia
| | - Derek D. Kennedy
- School of Biomolecular and Biomedical Sciences, Griffith UniversityNathan, QLD 4111, Australia
| | - Roger R. Reddel
- Children's Medical Research Institute214 Hawkesbury Road, Westmead, NSW 2145, Australia
| | | | | | - Ross Smith
- To whom correspondence should be addressed. Tel: +61 7 3365 4627; Fax: +61 7 3365 4699;
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26
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Süleymanoĝlu E. Molecular phylogenetics and functional evolution of major RNA recognition domains of recently cloned and characterized autoimmune RNA-binding particle. Genomics Proteomics Bioinformatics 2005; 1:310-20. [PMID: 15629060 PMCID: PMC5172410 DOI: 10.1016/s1672-0229(03)01037-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are spliceosomal macromolecular assemblages and thus actively participate in pre-mRNA metabolism. They are composed of evolutionarily conserved and tandemly repeated motifs, where both RNA-binding and protein-protein recognition occur to achieve cellular activities. By yet unknown mechanisms, these ribonucleoprotein (RNP) particles are targeted by autoantibodies and hence play significant role in a variety of human systemic autoimmune diseases. This feature makes them important prognostic markers in terms of molecular epidemiology and pathogenesis of autoimmunity. Since RNP domain is one of the most conserved and widespread scaffolds, evolutionary analyses of these RNA-binding domains can provide further clues on disease-specific epitope formation. The study presented herein represents a sequence comparison of RNA-recognition regions of recently cloned and characterized human hnRNP A3 with those of other relevant hnRNP A/B-type proteins. Their implications in human autoimmunity are particularly emphasized.
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Affiliation(s)
- Erhan Süleymanoĝlu
- Medical Faculty, Vienna Biocenter, Institute of Biochemistry, University of Vienna, Vienna, Austria.
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27
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Bonnal S, Pileur F, Orsini C, Parker F, Pujol F, Prats AC, Vagner S. Heterogeneous nuclear ribonucleoprotein A1 is a novel internal ribosome entry site trans-acting factor that modulates alternative initiation of translation of the fibroblast growth factor 2 mRNA. J Biol Chem 2004; 280:4144-53. [PMID: 15525641 DOI: 10.1074/jbc.m411492200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alternative initiation of translation of the human fibroblast growth factor 2 (FGF-2) mRNA at five in-frame CUG or AUG translation initiation codons requires various RNA cis-acting elements, including an internal ribosome entry site (IRES). Here we describe the purification of a trans-acting factor controlling FGF-2 mRNA translation achieved by several biochemical purification approaches. We have identified the heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) as a factor that binds to the FGF-2 5'-leader RNA and that also complements defective FGF-2 translation in vitro in rabbit reticulocyte lysate. Recombinant hnRNP A1 stimulates in vitro translation at the four IRES-dependent initiation codons but has no effect on the cap-dependent initiation codon. Consistent with a role of hnRNP A1 in the control of alternative initiation of translation, short interfering RNA-mediated knock down of hnRNP A1 specifically inhibits translation at the four IRES-dependent initiation codons. Furthermore, hnRNP A1 binds to the FGF-2 IRES, implicating this interaction in the control of alternative initiation of translation.
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Affiliation(s)
- Sophie Bonnal
- INSERM U589, Institut Louis Bugnard, Hopital Rangueil, TSA 50032, 31059 Toulouse Cedex 9, France
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28
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Khateb S, Weisman-Shomer P, Hershco I, Loeb LA, Fry M. Destabilization of tetraplex structures of the fragile X repeat sequence (CGG)n is mediated by homolog-conserved domains in three members of the hnRNP family. Nucleic Acids Res 2004; 32:4145-54. [PMID: 15302914 PMCID: PMC514371 DOI: 10.1093/nar/gkh745] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hairpin or tetrahelical structures formed by a d(CGG)n sequence in the FMR1 gene are thought to promote expansion of the repeat tract. Subsequent to this expansion FMR1 is silenced and fragile X syndrome ensues. The injurious effects of d(CGG)n secondary structures may potentially be countered by agents that act to decrease their stability. We showed previously that the hnRNP-related protein CBF-A destabilized G'2 bimolecular tetraplex structures of d(CGG)n. Analysis of mutant proteins revealed that the CBF-A-conserved domains RNP11 and ATP/GTP binding box were sufficient and necessary for G'2 d(CGG)n disruption while the RNP21 motif inhibited the destabilization activity. Here, we report that a C-terminal fragment of CBF-A whose only remaining conserved domain was the ATP/GTP binding motif, disrupted G'2 d(CGG)n more selectively than wild-type CBF-A. Further, two additional members of the hnRNP family, hnRNP A2 and mutant hnRNP A1 effectively destabilized G'2 d(CGG)n. Examination of mutant hnRNP A2 proteins revealed that, similar to CBF-A, their RNP11 element and ATP/GTP binding motif mediated G'2 d(CGG)n disruption, while the RNP21 element blocked their action. Similarly, the RNP11 and RNP21 domains of hnRNP A1 were, respectively, positive and negative mediators of G'2 d(CGG)n destabilization. Last, employing the same conserved motifs that mediated disruption of the DNA tetraplex G'2 d(CGG)n, hnRNP A2 destabilized r(CGG)n RNA tetraplex.
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Affiliation(s)
- Samer Khateb
- Unit of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, P.O. Box 9649, Haifa 31096, Israel
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29
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Ma H, Liu Q, Diamond SL, Pierce EA. Mouse embryonic stem cells efficiently lipofected with nuclear localization peptide result in a high yield of chimeric mice and retain germline transmission potency. Methods 2004; 33:113-20. [PMID: 15121165 DOI: 10.1016/j.ymeth.2003.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2003] [Indexed: 11/29/2022] Open
Abstract
Embryonic stem (ES) cells are an important tool in developmental biology, genomics, and transgenic methods, as well as in potential clinical applications such as gene therapy or tissue engineering. Electroporation is the standard transfection method for mouse ES (mES) cells because lipofection is quite inefficient. It is also unclear if mES cells treated with cationic lipids maintain pluripotency. We have developed a simple lipofection method for high efficiency transfection and stable transgene expression by employing the nonclassical nuclear localization signal M9 derived from the heterogeneous nuclear ribonucleoprotein A1. In contrast to using 20 microg DNA for 10 x 10(6) cells via electroporation which resulted in 10-20 positive cells/mm2, M9-assisted lipofection of 2 x 10(5) cells with 2 microg DNA resulted in > 150 positive cells/mm2. Electroporation produced only 0.16% EGFP positive cells with fluorescence intensity (FI) > 1000 by FACS assay, while M9-lipofection produced 36-fold more highly EGFP positive cells (5.75%) with FI > 1000. Using 2.5 x 10(6) ES cells and 6 microg linearized DNA followed by selection with G418, electroporation yielded 17 EGFP expressing colonies, while M9-assisted lipofection yielded 72 EGFP expressing colonies. The mES cells that stably expressed EGFP following M9-assisted lipofection yielded > 66% chimeric mice (8 of 12) and contributed efficiently to the germline. In an example of gene targeting, a knock-in mouse was produced from an ES clone screened from 200 G418-resistant colonies generated via M9-assisted lipofection. To our knowledge, this is the first report of generation of transgenic or knock-in mice obtained from lipofected mES cells and this method may facilitate large scale genomic studies of ES developmental biology or large scale generation of mouse models of human disease.
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Affiliation(s)
- Haiching Ma
- Department of Chemical Engineering, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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30
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Chai Q, Zheng L, Zhou M, Turchi JJ, Shen B. Interaction and stimulation of human FEN-1 nuclease activities by heterogeneous nuclear ribonucleoprotein A1 in alpha-segment processing during Okazaki fragment maturation. Biochemistry 2004; 42:15045-52. [PMID: 14690413 DOI: 10.1021/bi035364t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
High-fidelity DNA replication depends on both accurate incorporation of nucleotides in the newly synthesized strand and the maturation of Okazaki fragments. In eukaryotic cells, the latter is accomplished by a series of coordinated actions of a set of structure-specific nucleases, which, with the assistance of accessory proteins, recognize branched RNA/DNA configurations. In the current model of Okazaki fragment maturation, displacement of a 27-nucleotide or longer flap is envisioned to attract replication protein A (RPA), which inhibits flap endonuclease-1 (FEN-1) but stimulates Dna2 nuclease for cleavage. Dna2 cleavage generates a short flap of 5-7 nucleotides, which resists binding by RPA and further cleavage by Dna2. FEN-1 then removes the remaining flap to produce a suitable substrate for ligation. However, FEN-1 is not efficient in cleaving the short flap, and we therefore set out to identify cellular factors that might regulate FEN-1 activity. Through co-immunoprecipitation experiments, we have isolated heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), which forms a direct complex with FEN-1 and stimulates its enzymatic activities. The stimulation by hnRNP A1 is most dramatic using DNA substrates with short flaps. With longer flap substrates the hnRNP A1 effect is more modest and is suppressed by the addition of RPA. A model is provided to explain the possible in vivo role of this interaction and activity in Okazaki fragment maturation.
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Affiliation(s)
- Qing Chai
- Division of Molecular Biology, City of Hope National Medical Center and Beckman Research Institute, Duarte, California 91010, USA
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31
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Zahler AM, Damgaard CK, Kjems J, Caputi M. SC35 and heterogeneous nuclear ribonucleoprotein A/B proteins bind to a juxtaposed exonic splicing enhancer/exonic splicing silencer element to regulate HIV-1 tat exon 2 splicing. J Biol Chem 2004; 279:10077-84. [PMID: 14703516 DOI: 10.1074/jbc.m312743200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Splicing of the human immunodeficiency virus, type 1, primary transcript is highly regulated. Maintaining the proper equilibrium among spliced, unspliced, and partially spliced isoforms is essential for the replication of the virus. Here we characterize a complex cis-acting element located in tat exon 2 that is required for the splicing regulation of the upstream intron. An exonic splicing enhancer (ESE) and an exonic splicing silencer (ESS) are both located within the regulatory element. Heterogeneous nuclear ribonucleoprotein (hnRNP) A/B proteins bind the ESS to repress splicing, whereas the SR protein SC35 binds the ESE to activate it. We show that the SC35 and the hnRNP A1 binding sites overlap within the juxtaposed ESE/ESS. We propose that hnRNP A1 binding to the ESS inhibits splicing of the upstream intron by directly masking the SC35 binding site.
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Affiliation(s)
- Alan M Zahler
- Department of Molecular, Cellular and Developmental Biology and Center for Molecular Biology of RNA, Sinsheimer Laboratories, University of California, Santa Cruz 95064, USA
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32
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Enokizono Y, Matsugami A, Uesugi S, Fukuda H, Tsuchiya N, Sugimura T, Nagao M, Nakagama H, Katahira M. Destruction of quadruplex by proteins, and its biological implications in replication and telomere maintenance. ACTA ACUST UNITED AC 2003:231-2. [PMID: 14510465 DOI: 10.1093/nass/3.1.231] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The minisatellite DNA Pc-1 consists of tandem repeats of d(GGCAG). We previously reported that a d(GGCAG)n strand folds into an intramolecular quadruplex under physiological conditions and that during replication the progression of DNA polymerase is blocked by the quadruplex in vitro. Therefore, the formation of the quadruplex was supposed to be responsible for the hypermutable features of Pc-1. Then, we have identified proteins that bind to Pc-1, one of which is hnRNP A1. Here, we have demonstrated that hnRNP A1 destroys the quadruplex of Pc-1 on binding and abrogates the arrest of DNA polymerase at the repeat. Thus, hnRNP A1 functions as if it is a chaperon to assist Pc-1 DNA to form the proper folding suitable for replication. We have also found that hnRNP A1 and a related protein, hnRNP D, destroy the quadruplex of telomere DNA, which suggests the involvement of these proteins in telomere maintenance as DNA chaperons.
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Affiliation(s)
- Yoshiaki Enokizono
- Graduate School of Environmental and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
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33
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Chabot B, LeBel C, Hutchison S, Nasim FH, Simard MJ. Heterogeneous nuclear ribonucleoprotein particle A/B proteins and the control of alternative splicing of the mammalian heterogeneous nuclear ribonucleoprotein particle A1 pre-mRNA. Prog Mol Subcell Biol 2003; 31:59-88. [PMID: 12494763 DOI: 10.1007/978-3-662-09728-1_3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- B Chabot
- Département de Microbiologie et d'Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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