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Perzanowska O, Smietanski M, Jemielity J, Kowalska J. Chemically Modified Poly(A) Analogs Targeting PABP: Structure Activity Relationship and Translation Inhibitory Properties. Chemistry 2022; 28:e202201115. [PMID: 35575378 PMCID: PMC9400960 DOI: 10.1002/chem.202201115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Indexed: 11/13/2022]
Abstract
Poly(A)‐binding protein (PABP) is an essential element of cellular translational machinery. Recent studies have revealed that poly(A) tail modifications can modulate mRNA stability and translational potential, and that oligoadenylate‐derived PABP ligands can act as effective translational inhibitors with potential applications in pain management. Although extensive research has focused on protein‐RNA and protein‐protein interactions involving PABPs, further studies are required to examine the ligand specificity of PABP. In this study, we developed a microscale thermophoresis‐based assay to probe the interactions between PABP and oligoadenylate analogs containing different chemical modifications. Using this method, we evaluated oligoadenylate analogs modified with nucleobase, ribose, and phosphate moieties to identify modification hotspots. In addition, we determined the susceptibility of the modified oligos to CNOT7 to identify those with the potential for increased cellular stability. Consequently, we selected two enzymatically stable oligoadenylate analogs that inhibit translation in rabbit reticulocyte lysates with a higher potency than a previously reported PABP ligand. We believe that the results presented in this study and the implemented methodology can be capitalized upon in the future development of RNA‐based biological tools.
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Affiliation(s)
- Olga Perzanowska
- Division of Biophysics Faculty of Physics University of Warsaw Ludwika Pasteura 5 02-093 Warsaw Poland
- Centre of New Technologies University of Warsaw Stefana Banacha 2c 02-097 Warsaw Poland
| | - Miroslaw Smietanski
- Centre of New Technologies University of Warsaw Stefana Banacha 2c 02-097 Warsaw Poland
| | - Jacek Jemielity
- Centre of New Technologies University of Warsaw Stefana Banacha 2c 02-097 Warsaw Poland
| | - Joanna Kowalska
- Division of Biophysics Faculty of Physics University of Warsaw Ludwika Pasteura 5 02-093 Warsaw Poland
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2
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Roscoe S, Manni E, Roberts M, Ananvoranich S. Formation of mRNP granules in Toxoplasma gondii during the lytic cycle. Mol Biochem Parasitol 2020; 242:111349. [PMID: 33383066 DOI: 10.1016/j.molbiopara.2020.111349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/01/2022]
Abstract
Two poly(A) binding proteins (PABPs) of Toxoplasma gondii, were identified and characterized. They were named TgPABPC and TgPABPN as they were found to localize in the cytoplasm and nucleus respectively. TgPABPC, which colocalizes with mRNA granules, is therefore used as a cellular marker of mRNP granules. We detected that the formation of mRNP granules was independent of polymerized microtubules, and that the granules were distributed stochastically within the cytosol. Formation of mRNP granules was found to occur prior to parasite egress when a Ca2+ ionophore is used to induce egress. It was also found that maturation of mRNP granules could be described as a two-phase process. First, prior to host cell lysis, mRNP granules were formed rapidly within the cytosol. Second, the mRNP granule load was reduced within 10 min post egress. To investigate the link between translational state and mRNP granule formation, treatments with salubrinal, nutrient deprivation, and pH stress were used. While salubrinal induced granule formation in tachyzoites, nutrient starvation and pH stress showed no induction effect on mRNP granule formation. Interestingly, salubrinal treatment in bradyzoites did not induce RNP granule formation, thus suggesting that mRNP granule formation is not a ubiquitous response or directly related to translational repression. Instead, mRNP granule formation is likely a response to the rapid increase in non-translating RNA brought on by sudden changes in translational state.
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Affiliation(s)
- Scott Roscoe
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, N9B3P4, Canada
| | - Emad Manni
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, N9B3P4, Canada
| | - Mikayla Roberts
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, N9B3P4, Canada
| | - Sirinart Ananvoranich
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, N9B3P4, Canada.
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3
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Ford LK, Fioriti L. Coiled-Coil Motifs of RNA-Binding Proteins: Dynamicity in RNA Regulation. Front Cell Dev Biol 2020; 8:607947. [PMID: 33330512 PMCID: PMC7710910 DOI: 10.3389/fcell.2020.607947] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/30/2020] [Indexed: 01/29/2023] Open
Abstract
Neuronal granules are biomolecular condensates that concentrate high quantities of RNAs and RNA-related proteins within neurons. These dense packets of information are trafficked from the soma to distal sites rich in polysomes, where local protein synthesis can occur. Movement of neuronal granules to distal sites, and local protein synthesis, play a critical role in synaptic plasticity. The formation of neuronal granules is intriguing; these granules lack a membrane and instead phase separate due to protein and RNA interactions. Low complexity motifs and RNA binding domains are highly prevalent in these proteins. Here, we introduce the role that coiled-coil motifs play in neuronal granule proteins, and investigate the structure-function relationship of coiled-coil proteins in RNA regulation. Interestingly, low complexity domains and coiled-coil motifs are highly dynamic, allowing for increased functional response to environmental influences. Finally, biomolecular condensates have been suggested to drive the formation of toxic, neurodegenerative proteins such as TDP-43 and tau. Here, we review the conversion of coiled-coil motifs to amyloid structures, and speculate a role that neuronal granules play in coiled-coil to amyloid conversions of neurodegenerative proteins.
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Affiliation(s)
- Lenzie K Ford
- Department of Neuroscience, Zuckerman Institute, Columbia University, New York, NY, United States
| | - Luana Fioriti
- Laboratory of Molecular Mechanisms of Polyglutamine Disorders, Department of Neuroscience, Dulbecco Telethon Institute, Istituto di Ricerche Farmacologiche Mario Negri (IRCCS), Milan, Italy
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4
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Crystal Structure of a Variant PAM2 Motif of LARP4B Bound to the MLLE Domain of PABPC1. Biomolecules 2020; 10:biom10060872. [PMID: 32517187 PMCID: PMC7356810 DOI: 10.3390/biom10060872] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/31/2020] [Accepted: 06/04/2020] [Indexed: 12/15/2022] Open
Abstract
Eukaryotic cells determine the protein output of their genetic program by regulating mRNA transcription, localization, translation and turnover rates. This regulation is accomplished by an ensemble of RNA-binding proteins (RBPs) that bind to any given mRNA, thus forming mRNPs. Poly(A) binding proteins (PABPs) are prominent members of virtually all mRNPs that possess poly(A) tails. They serve as multifunctional scaffolds, allowing the recruitment of diverse factors containing a poly(A)-interacting motif (PAM) into mRNPs. We present the crystal structure of the variant PAM motif (termed PAM2w) in the N-terminal part of the positive translation factor LARP4B, which binds to the MLLE domain of the poly(A) binding protein C1 cytoplasmic 1 (PABPC1). The structural analysis, along with mutational studies in vitro and in vivo, uncovered a new mode of interaction between PAM2 motifs and MLLE domains.
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5
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Webster MW, Chen YH, Stowell JAW, Alhusaini N, Sweet T, Graveley BR, Coller J, Passmore LA. mRNA Deadenylation Is Coupled to Translation Rates by the Differential Activities of Ccr4-Not Nucleases. Mol Cell 2019; 70:1089-1100.e8. [PMID: 29932902 PMCID: PMC6024076 DOI: 10.1016/j.molcel.2018.05.033] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/17/2018] [Accepted: 05/24/2018] [Indexed: 01/01/2023]
Abstract
Translation and decay of eukaryotic mRNAs is controlled by shortening of the poly(A) tail and release of the poly(A)-binding protein Pab1/PABP. The Ccr4-Not complex contains two exonucleases—Ccr4 and Caf1/Pop2—that mediate mRNA deadenylation. Here, using a fully reconstituted biochemical system with proteins from the fission yeast Schizosaccharomyces pombe, we show that Pab1 interacts with Ccr4-Not, stimulates deadenylation, and differentiates the roles of the nuclease enzymes. Surprisingly, Pab1 release relies on Ccr4 activity. In agreement with this, in vivo experiments in budding yeast show that Ccr4 is a general deadenylase that acts on all mRNAs. In contrast, Caf1 only trims poly(A) not bound by Pab1. As a consequence, Caf1 is a specialized deadenylase required for the selective deadenylation of transcripts with lower rates of translation elongation and reduced Pab1 occupancy. These findings reveal a coupling between the rates of translation and deadenylation that is dependent on Pab1 and Ccr4-Not. Poly(A)-binding protein is efficiently released by Ccr4-Not nuclease activity Ccr4, but not Caf1, removes poly(A) tails bound to Pab1 Ccr4 acts on all transcripts and Caf1 acts on transcripts with low codon optimality Deadenylation by Ccr4-Not connects translation with mRNA stability
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Affiliation(s)
| | - Ying-Hsin Chen
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH 44106-4960, USA
| | | | - Najwa Alhusaini
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH 44106-4960, USA
| | - Thomas Sweet
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH 44106-4960, USA
| | - Brenton R Graveley
- Department of Genetics and Developmental Biology, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Jeff Coller
- The Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH 44106-4960, USA.
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6
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Dynamic interaction of poly(A)-binding protein with the ribosome. Sci Rep 2018; 8:17435. [PMID: 30487538 PMCID: PMC6261967 DOI: 10.1038/s41598-018-35753-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 11/09/2018] [Indexed: 01/15/2023] Open
Abstract
Eukaryotic mRNA has a cap structure and a poly(A) tail at the 5′ and 3′ ends, respectively. The cap structure is recognized by eIF (eukaryotic translation initiation factor) 4 F, while the poly(A) tail is bound by poly(A)-binding protein (PABP). PABP has four RNA recognition motifs (RRM1–4), and RRM1-2 binds both the poly(A) tail and eIF4G component of eIF4F, resulting in enhancement of translation. Here, we show that PABP interacts with the 40S and 60S ribosomal subunits dynamically via RRM2-3 or RRM3-4. Using a reconstituted protein expression system, we demonstrate that wild-type PABP activates translation in a dose-dependent manner, while a PABP mutant that binds poly(A) RNA and eIF4G, but not the ribosome, fails to do so. From these results, functional significance of the interaction of PABP with the ribosome is discussed.
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7
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Nithin C, Ghosh P, Bujnicki JM. Bioinformatics Tools and Benchmarks for Computational Docking and 3D Structure Prediction of RNA-Protein Complexes. Genes (Basel) 2018; 9:genes9090432. [PMID: 30149645 PMCID: PMC6162694 DOI: 10.3390/genes9090432] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/26/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022] Open
Abstract
RNA-protein (RNP) interactions play essential roles in many biological processes, such as regulation of co-transcriptional and post-transcriptional gene expression, RNA splicing, transport, storage and stabilization, as well as protein synthesis. An increasing number of RNP structures would aid in a better understanding of these processes. However, due to the technical difficulties associated with experimental determination of macromolecular structures by high-resolution methods, studies on RNP recognition and complex formation present significant challenges. As an alternative, computational prediction of RNP interactions can be carried out. Structural models obtained by theoretical predictive methods are, in general, less reliable compared to models based on experimental measurements but they can be sufficiently accurate to be used as a basis for to formulating functional hypotheses. In this article, we present an overview of computational methods for 3D structure prediction of RNP complexes. We discuss currently available methods for macromolecular docking and for scoring 3D structural models of RNP complexes in particular. Additionally, we also review benchmarks that have been developed to assess the accuracy of these methods.
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Affiliation(s)
- Chandran Nithin
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, PL-02-109 Warsaw, Poland.
| | - Pritha Ghosh
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, PL-02-109 Warsaw, Poland.
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, ul. Ks. Trojdena 4, PL-02-109 Warsaw, Poland.
- Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, PL-61-614 Poznan, Poland.
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8
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Harvey RF, Smith TS, Mulroney T, Queiroz RML, Pizzinga M, Dezi V, Villenueva E, Ramakrishna M, Lilley KS, Willis AE. Trans-acting translational regulatory RNA binding proteins. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1465. [PMID: 29341429 PMCID: PMC5947564 DOI: 10.1002/wrna.1465] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/31/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022]
Abstract
The canonical molecular machinery required for global mRNA translation and its control has been well defined, with distinct sets of proteins involved in the processes of translation initiation, elongation and termination. Additionally, noncanonical, trans-acting regulatory RNA-binding proteins (RBPs) are necessary to provide mRNA-specific translation, and these interact with 5' and 3' untranslated regions and coding regions of mRNA to regulate ribosome recruitment and transit. Recently it has also been demonstrated that trans-acting ribosomal proteins direct the translation of specific mRNAs. Importantly, it has been shown that subsets of RBPs often work in concert, forming distinct regulatory complexes upon different cellular perturbation, creating an RBP combinatorial code, which through the translation of specific subsets of mRNAs, dictate cell fate. With the development of new methodologies, a plethora of novel RNA binding proteins have recently been identified, although the function of many of these proteins within mRNA translation is unknown. In this review we will discuss these methodologies and their shortcomings when applied to the study of translation, which need to be addressed to enable a better understanding of trans-acting translational regulatory proteins. Moreover, we discuss the protein domains that are responsible for RNA binding as well as the RNA motifs to which they bind, and the role of trans-acting ribosomal proteins in directing the translation of specific mRNAs. This article is categorized under: RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Translation > Translation Regulation Translation > Translation Mechanisms.
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Affiliation(s)
| | - Tom S. Smith
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Rayner M. L. Queiroz
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | | | - Eneko Villenueva
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | | - Kathryn S. Lilley
- Cambridge Centre for Proteomics, Department of BiochemistryUniversity of CambridgeCambridgeUK
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9
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Nuclear, Cytosolic, and Surface-Localized Poly(A)-Binding Proteins of Plasmodium yoelii. mSphere 2018; 3:mSphere00435-17. [PMID: 29359180 PMCID: PMC5760745 DOI: 10.1128/msphere.00435-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/12/2017] [Indexed: 12/22/2022] Open
Abstract
Malaria remains one of the great global health problems. The parasite that causes malaria (Plasmodium genus) relies upon exquisite control of its transmission between vertebrate hosts and mosquitoes. One crucial way that it does so is by proactively producing mRNAs needed to establish the new infection but by silencing and storing them until they are needed. One key protein in this process of translational repression in model eukaryotes is poly(A)-binding protein (PABP). Here we have shown that Plasmodium yoelii utilizes both a nuclear PABP and a cytosolic PABP, both of which bind specifically to polyadenylated RNA sequences. Moreover, we find that the cytosolic PABP forms chains in vitro, consistent with its appreciated role in coating the poly(A) tails of mRNA. Finally, we have also verified that, surprisingly, the cytosolic PABP is found on the surface of Plasmodium sporozoites. Taking the data together, we propose that Plasmodium utilizes a more metazoan-like strategy for RNA metabolism using specialized PABPs. Malaria is a devastating illness that causes approximately 500,000 deaths annually. The malaria-causing parasite (Plasmodium genus) uses the process of translational repression to regulate its growth, development, and transmission. As poly(A)-binding proteins (PABP) have been identified as critical components of RNA metabolism and translational repression in model eukaryotes and in Plasmodium, we have identified and investigated two PABPs in Plasmodium yoelii, PyPABP1 and PyPABP2. In contrast to most single-celled eukaryotes, Plasmodium closely resembles metazoans and encodes both a nuclear PABP and a cytosolic PABP; here, we provide multiple lines of evidence in support of this observation. The conserved domain architectures of PyPABP1 and PyPABP2 resemble those of yeast and metazoans, while multiple independent binding assays demonstrated their ability to bind very strongly and specifically to poly(A) sequences. Interestingly, we also observed that purified PyPABP1 forms homopolymeric chains despite exhaustive RNase treatment in vitro. Finally, we show by indirect immunofluorescence assays (IFAs) that PyPABP1 and PyPABP2 are cytoplasm- and nucleus-associated PABPs during the blood stages of the life cycle. Surprisingly, however, PyPABP1 was instead observed to also be localized on the surface of transmitted salivary gland sporozoites and to be deposited in trails when parasites glide on a substrate. This is the third RNA-binding protein verified to be found on the sporozoite surface, and the data may point to an unappreciated RNA-centered interface between the host and parasite. IMPORTANCE Malaria remains one of the great global health problems. The parasite that causes malaria (Plasmodium genus) relies upon exquisite control of its transmission between vertebrate hosts and mosquitoes. One crucial way that it does so is by proactively producing mRNAs needed to establish the new infection but by silencing and storing them until they are needed. One key protein in this process of translational repression in model eukaryotes is poly(A)-binding protein (PABP). Here we have shown that Plasmodium yoelii utilizes both a nuclear PABP and a cytosolic PABP, both of which bind specifically to polyadenylated RNA sequences. Moreover, we find that the cytosolic PABP forms chains in vitro, consistent with its appreciated role in coating the poly(A) tails of mRNA. Finally, we have also verified that, surprisingly, the cytosolic PABP is found on the surface of Plasmodium sporozoites. Taking the data together, we propose that Plasmodium utilizes a more metazoan-like strategy for RNA metabolism using specialized PABPs.
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10
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Abstract
Poly(A) tails are found at the 3' end of almost every eukaryotic mRNA and are important for the stability of mRNAs and their translation into proteins. Thus, removal of the poly(A) tail, a process called deadenylation, is critical for regulation of gene expression. Most deadenylation enzymes are components of large multi-protein complexes. Here, we describe an in vitro deadenylation assay developed to study the exonucleolytic activities of the multi-protein Ccr4-Not and Pan2-Pan3 complexes. We discuss how this assay can be used with short synthetic RNAs, as well as longer RNA substrates generated using in vitro transcription. Importantly, quantitation of the reactions allows detailed analyses of deadenylation in the presence and absence of accessory factors, leading to new insights into targeted mRNA decay.
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11
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Muthuramalingam M, Wang Y, Li Y, Mahalingam R. Interacting protein partners of Arabidopsis RNA-binding protein AtRBP45b. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:327-334. [PMID: 28039930 DOI: 10.1111/plb.12540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/29/2016] [Indexed: 05/19/2023]
Abstract
RNA binding proteins, important players in post-transcriptional gene regulation, usually exist in ribonuclear complexes. However, even in model systems like Arabidopsis characterisation of RBP associated proteins is limited. In this study, we investigated the interacting proteins of the Arabidopsis AtRBP45b, which is involved in stress signalling. In vivo localisation of AtRBP45b was conducted using 35S-GFP. FLAG-tagged AtRBP45b under control of the 35S promoter in the Atrbp45b-1 mutant background was used to pull down AtRBP45b interacting proteins. Yeast two-hybrid analysis, fluorescence energy resonance transfer assays were used to confirm the veracity of the AtRBP45b interacting proteins. In planta GFP-tagging indicated AtRBP45b is localised to the nucleus and the cytosol. AtRBP45b protein has a N-terminal proline-rich region and a C-terminal glutamine-rich domain that are usually involved in protein-protein interactions. Co-immunoprecipitation followed by mass spectrometry-based protein sequencing led to identification of 30 proteins that interacted with AtRBP45b. Using information from interactome databases (BIOGRID, INTACT and STRING), pull-down assays and localisation data, 12 putative interacting proteins were selected for yeast two-hybrid analysis. Cap-binding protein (CBP20, At5g44200) and polyA-binding protein (PAB8, At1g49760) were shown to interact with AtRBP45b. Based on its interacting partners we speculate that AtRBP45b may play an important role in RNA metabolism, especially in aspects related to mRNA stability and translation initiation during stress conditions in plants.
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Affiliation(s)
- M Muthuramalingam
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Y Wang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- Department of Plant Biology, Ecology and Evolution, Oklahoma State University, Stillwater, OK, USA
| | - Y Li
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- College of Life Sciences, Henan Normal University, Xinxiang, Henan, China
| | - R Mahalingam
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK, USA
- USDA-ARS, Cereal Crops Research Unit, Madison, WI, USA
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12
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Characterization of the Role of Hexamer AGUAAA and Poly(A) Tail in Coronavirus Polyadenylation. PLoS One 2016; 11:e0165077. [PMID: 27760233 PMCID: PMC5070815 DOI: 10.1371/journal.pone.0165077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/05/2016] [Indexed: 01/21/2023] Open
Abstract
Similar to eukaryotic mRNA, the positive-strand coronavirus genome of ~30 kilobases is 5’-capped and 3’-polyadenylated. It has been demonstrated that the length of the coronaviral poly(A) tail is not static but regulated during infection; however, little is known regarding the factors involved in coronaviral polyadenylation and its regulation. Here, we show that during infection, the level of coronavirus poly(A) tail lengthening depends on the initial length upon infection and that the minimum length to initiate lengthening may lie between 5 and 9 nucleotides. By mutagenesis analysis, it was found that (i) the hexamer AGUAAA and poly(A) tail are two important elements responsible for synthesis of the coronavirus poly(A) tail and may function in concert to accomplish polyadenylation and (ii) the function of the hexamer AGUAAA in coronaviral polyadenylation is position dependent. Based on these findings, we propose a process for how the coronaviral poly(A) tail is synthesized and undergoes variation. Our results provide the first genetic evidence to gain insight into coronaviral polyadenylation.
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13
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Melamed D, Young DL, Miller CR, Fields S. Combining natural sequence variation with high throughput mutational data to reveal protein interaction sites. PLoS Genet 2015; 11:e1004918. [PMID: 25671604 PMCID: PMC4335499 DOI: 10.1371/journal.pgen.1004918] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/24/2014] [Indexed: 12/29/2022] Open
Abstract
Many protein interactions are conserved among organisms despite changes in the amino acid sequences that comprise their contact sites, a property that has been used to infer the location of these sites from protein homology. In an inter-species complementation experiment, a sequence present in a homologue is substituted into a protein and tested for its ability to support function. Therefore, substitutions that inhibit function can identify interaction sites that changed over evolution. However, most of the sequence differences within a protein family remain unexplored because of the small-scale nature of these complementation approaches. Here we use existing high throughput mutational data on the in vivo function of the RRM2 domain of the Saccharomyces cerevisiae poly(A)-binding protein, Pab1, to analyze its sites of interaction. Of 197 single amino acid differences in 52 Pab1 homologues, 17 reduce the function of Pab1 when substituted into the yeast protein. The majority of these deleterious mutations interfere with the binding of the RRM2 domain to eIF4G1 and eIF4G2, isoforms of a translation initiation factor. A large-scale mutational analysis of the RRM2 domain in a two-hybrid assay for eIF4G1 binding supports these findings and identifies peripheral residues that make a smaller contribution to eIF4G1 binding. Three single amino acid substitutions in yeast Pab1 corresponding to residues from the human orthologue are deleterious and eliminate binding to the yeast eIF4G isoforms. We create a triple mutant that carries these substitutions and other humanizing substitutions that collectively support a switch in binding specificity of RRM2 from the yeast eIF4G1 to its human orthologue. Finally, we map other deleterious substitutions in Pab1 to inter-domain (RRM2–RRM1) or protein-RNA (RRM2–poly(A)) interaction sites. Thus, the combined approach of large-scale mutational data and evolutionary conservation can be used to characterize interaction sites at single amino acid resolution. The interactions of proteins with each other are essential for almost all biological processes. Many of the sites of protein contact have evolved to maintain these interactions, but use different sets of amino acid residues. As a result, the residues at a contact site in a protein from one species might not allow a protein interaction when they are tested in a second species. This property underlies the idea of inter-species complementation assays, which test the effect of replacing protein segments from one species by their equivalents from another species. However, this approach has been highly limited in the number of changes that could be analyzed in a single study. Here, we present a novel approach that combines a high-throughput analysis of mutations in a single protein with the set of natural sequences corresponding to evolutionarily divergent variants of this protein. This integration step allows us to map at high resolution both sites of inter-protein interaction as well as intra-protein interaction. Our approach can be used with proteins that have limited functional and structural data, and it can be applied to improve the performance of computational tools that use sequence homology to predict function.
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Affiliation(s)
- Daniel Melamed
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - David L. Young
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Christina R. Miller
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Stanley Fields
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
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14
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Gallie DR, Liu R. Phylogenetic analysis reveals dynamic evolution of the poly(A)-binding protein gene family in plants. BMC Evol Biol 2014; 14:238. [PMID: 25421536 PMCID: PMC4252990 DOI: 10.1186/s12862-014-0238-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/07/2014] [Indexed: 01/05/2023] Open
Abstract
Background The poly(A)-binding protein (PABP) binds the poly(A) tail of eukaryotic mRNAs and functions to maintain the integrity of the mRNA while promoting protein synthesis through its interaction with eukaryotic translation initiation factor (eIF) 4G and eIF4B. PABP is encoded by a single gene in yeast and marine algae but during plant evolution the PABP gene family expanded substantially, underwent sequence divergence into three subclasses, and acquired tissue-specificity in gene family member expression. Although such changes suggest functional specialization, the size of the family and its sequence divergence have complicated an understanding of which gene family members may be foundational and which may represent more recent expansions of the family to meet the specific needs of speciation. Here, we examine the evolution of the plant PABP gene family to provide insight into these aspects of the family that may yield clues into the function of individual family members. Results The PABP gene family had expanded to two members by the appearance of fresh water algae and four members in non-vascular plants. In lycophytes, the first sequence divergence yielding a specific class member occurs. The earliest members of the gene family share greatest similarity to those modern members whose expression is confined to reproductive tissues, suggesting that supporting reproductive-associated gene expression is the most conserved function of this family. A family member sharing similarity to modern vegetative-associated members first appears in gymnosperms. Further elaboration of the reproductive-associated and vegetative-associated members occurred during the evolution of flowering plants. Conclusions Expansion of the plant PABP gene family began prior to the colonization of land. By the evolution of lycophytes, the first class member whose expression is confined to reproductive tissues in higher plants had appeared. A second class member whose expression is vegetative-associated appeared in gymnosperms and all three modern classes had fully evolved by the appearance of the first known basal angiosperm. The size of each PABP class underwent further expansion during subsequent evolution, especially in the Brassicaceae, suggesting that the family is undergoing dynamic evolution. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0238-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel R Gallie
- Department of Biochemistry, University of California, Riverside, CA, 92521-0129, USA.
| | - Renyi Liu
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521-0129, USA.
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Tessier SN, Audas TE, Wu CW, Lee S, Storey KB. The involvement of mRNA processing factors TIA-1, TIAR, and PABP-1 during mammalian hibernation. Cell Stress Chaperones 2014; 19:813-25. [PMID: 24590458 PMCID: PMC4389841 DOI: 10.1007/s12192-014-0505-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 01/10/2023] Open
Abstract
Mammalian hibernators survive low body temperatures, ischemia-reperfusion, and restricted nutritional resources via global reductions in energy-expensive cellular processes and selective increases in stress pathways. Consequently, studies that analyze hibernation uncover mechanisms which balance metabolism and support survival by enhancing stress tolerance. We hypothesized processing factors that influence messenger ribonucleic acid (mRNA) maturation and translation may play significant roles in hibernation. We characterized the amino acid sequences of three RNA processing proteins (T cell intracellular antigen 1 (TIA-1), TIA1-related (TIAR), and poly(A)-binding proteins (PABP-1)) from thirteen-lined ground squirrels (Ictidomys tridecemlineatus), which all displayed a high degree of sequence identity with other mammals. Alternate Tia-1 and TiaR gene variants were found in the liver with higher expression of isoform b versus a in both cases. The localization of RNA-binding proteins to subnuclear structures was assessed by immunohistochemistry and confirmed by subcellular fractionation; TIA-1 was identified as a major component of subnuclear structures with up to a sevenfold increase in relative protein levels in the nucleus during hibernation. By contrast, there was no significant difference in the relative protein levels of TIARa/TIARb in the nucleus, and a decrease was observed for TIAR isoforms in cytoplasmic fractions of torpid animals. Finally, we used solubility tests to analyze the formation of reversible aggregates that are associated with TIA-1/R function during stress; a shift towards the soluble fraction (TIA-1a, TIA-1b) was observed during hibernation suggesting enhanced protein aggregation was not present during torpor. The present study identifies novel posttranscriptional regulatory mechanisms that may play a role in reducing translational rates and/or mRNA processing under unfavorable environmental conditions.
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Affiliation(s)
- Shannon N. Tessier
- />Institute of Biochemistry, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6 Canada
| | - Timothy E. Audas
- />Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5 Canada
| | - Cheng-Wei Wu
- />Institute of Biochemistry, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6 Canada
| | - Stephen Lee
- />Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5 Canada
| | - Kenneth B. Storey
- />Institute of Biochemistry, Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6 Canada
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Eliseeva IA, Lyabin DN, Ovchinnikov LP. Poly(A)-binding proteins: structure, domain organization, and activity regulation. BIOCHEMISTRY (MOSCOW) 2014; 78:1377-91. [PMID: 24490729 DOI: 10.1134/s0006297913130014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RNA-binding proteins are of vital importance for mRNA functioning. Among these, poly(A)-binding proteins (PABPs) are of special interest due to their participation in virtually all mRNA-dependent events that is caused by their high affinity for A-rich mRNA sequences. Apart from mRNAs, PABPs interact with many proteins, thus promoting their involvement in cellular events. In the nucleus, PABPs play a role in polyadenylation, determine the length of the poly(A) tail, and may be involved in mRNA export. In the cytoplasm, they participate in regulation of translation initiation and either protect mRNAs from decay through binding to their poly(A) tails or stimulate this decay by promoting mRNA interactions with deadenylase complex proteins. This review presents modern notions of the role of PABPs in mRNA-dependent events; peculiarities of regulation of PABP amount in the cell and activities are also discussed.
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Affiliation(s)
- I A Eliseeva
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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17
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Tsai YS, Gomez SM, Wang Z. Prevalent RNA recognition motif duplication in the human genome. RNA (NEW YORK, N.Y.) 2014; 20:702-712. [PMID: 24667216 PMCID: PMC3988571 DOI: 10.1261/rna.044081.113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
The sequence-specific recognition of RNA by proteins is mediated through various RNA binding domains, with the RNA recognition motif (RRM) being the most frequent and present in >50% of RNA-binding proteins (RBPs). Many RBPs contain multiple RRMs, and it is unclear how each RRM contributes to the binding specificity of the entire protein. We found that RRMs within the same RBP (i.e., sibling RRMs) tend to have significantly higher similarity than expected by chance. Sibling RRM pairs from RBPs shared by multiple species tend to have lower similarity than those found only in a single species, suggesting that multiple RRMs within the same protein might arise from domain duplication followed by divergence through random mutations. This finding is exemplified by a recent RRM domain duplication in DAZ proteins and an ancient duplication in PABP proteins. Additionally, we found that different similarities between sibling RRMs are associated with distinct functions of an RBP and that the RBPs tend to contain repetitive sequences with low complexity. Taken together, this study suggests that the number of RBPs with multiple RRMs has expanded in mammals and that the multiple sibling RRMs may recognize similar target motifs in a cooperative manner.
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Affiliation(s)
| | - Shawn M. Gomez
- Curriculum in Bioinformatics and Computational Biology
- Department of Pharmacology
- Department of Computer Science
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Zefeng Wang
- Curriculum in Bioinformatics and Computational Biology
- Department of Pharmacology
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Manipulation of RNA Using Engineered Proteins with Customized Specificity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:199-225. [DOI: 10.1007/978-1-4939-1221-6_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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19
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Li X, Kazan H, Lipshitz HD, Morris QD. Finding the target sites of RNA-binding proteins. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 5:111-30. [PMID: 24217996 PMCID: PMC4253089 DOI: 10.1002/wrna.1201] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/27/2013] [Accepted: 10/01/2013] [Indexed: 12/15/2022]
Abstract
RNA–protein interactions differ from DNA–protein interactions because of the central role of RNA secondary structure. Some RNA-binding domains (RBDs) recognize their target sites mainly by their shape and geometry and others are sequence-specific but are sensitive to secondary structure context. A number of small- and large-scale experimental approaches have been developed to measure RNAs associated in vitro and in vivo with RNA-binding proteins (RBPs). Generalizing outside of the experimental conditions tested by these assays requires computational motif finding. Often RBP motif finding is done by adapting DNA motif finding methods; but modeling secondary structure context leads to better recovery of RBP-binding preferences. Genome-wide assessment of mRNA secondary structure has recently become possible, but these data must be combined with computational predictions of secondary structure before they add value in predicting in vivo binding. There are two main approaches to incorporating structural information into motif models: supplementing primary sequence motif models with preferred secondary structure contexts (e.g., MEMERIS and RNAcontext) and directly modeling secondary structure recognized by the RBP using stochastic context-free grammars (e.g., CMfinder and RNApromo). The former better reconstruct known binding preferences for sequence-specific RBPs but are not suitable for modeling RBPs that recognize shape and geometry of RNAs. Future work in RBP motif finding should incorporate interactions between multiple RBDs and multiple RBPs in binding to RNA. WIREs RNA 2014, 5:111–130. doi: 10.1002/wrna.1201
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Affiliation(s)
- Xiao Li
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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20
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Melamed D, Young DL, Gamble CE, Miller CR, Fields S. Deep mutational scanning of an RRM domain of the Saccharomyces cerevisiae poly(A)-binding protein. RNA (NEW YORK, N.Y.) 2013; 19:1537-51. [PMID: 24064791 PMCID: PMC3851721 DOI: 10.1261/rna.040709.113] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The RNA recognition motif (RRM) is the most common RNA-binding domain in eukaryotes. Differences in RRM sequences dictate, in part, both RNA and protein-binding specificities and affinities. We used a deep mutational scanning approach to study the sequence-function relationship of the RRM2 domain of the Saccharomyces cerevisiae poly(A)-binding protein (Pab1). By scoring the activity of more than 100,000 unique Pab1 variants, including 1246 with single amino acid substitutions, we delineated the mutational constraints on each residue. Clustering of residues with similar mutational patterns reveals three major classes, composed principally of RNA-binding residues, of hydrophobic core residues, and of the remaining residues. The first class also includes a highly conserved residue not involved in RNA binding, G150, which can be mutated to destabilize Pab1. A comparison of the mutational sensitivity of yeast Pab1 residues to their evolutionary conservation reveals that most residues tolerate more substitutions than are present in the natural sequences, although other residues that tolerate fewer substitutions may point to specialized functions in yeast. An analysis of ∼40,000 double mutants indicates a preference for a short distance between two mutations that display an epistatic interaction. As examples of interactions, the mutations N139T, N139S, and I157L suppress other mutations that interfere with RNA binding and protein stability. Overall, this study demonstrates that living cells can be subjected to a single assay to analyze hundreds of thousands of protein variants in parallel.
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Affiliation(s)
- Daniel Melamed
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - David L. Young
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Caitlin E. Gamble
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Christina R. Miller
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Stanley Fields
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
- Department of Medicine, University of Washington, Seattle, Washington 98195, USA
- Corresponding authorE-mail
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21
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Goss DJ, Kleiman FE. Poly(A) binding proteins: are they all created equal? WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:167-79. [PMID: 23424172 DOI: 10.1002/wrna.1151] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The PABP family of proteins were originally thought of as a simple shield for the mRNA poly(A) tail. Years of research have shown that PABPs interact not only with the poly(A) tail, but also with specific sequences in the mRNA, having a general and specific role on the metabolism of different mRNAs. The complexity of PABPs function is increased by the interactions of PABPs with factors involved in different cellular functions. PABPs participate in all the metabolic pathways of the mRNA: polyadenylation/deadenylation, mRNA export, mRNA surveillance, translation, mRNA degradation, microRNA-associated regulation, and regulation of expression during development. In this review, we update information on the roles of PABPs and emerging data on the specific interactions of PABP homologs. Specific functions of individual members of PABPC family in development and viral infection are beginning to be elucidated. However, the interactions are complex and recent evidence for exchange of nuclear and cytoplasmic forms of the proteins, as well as post-translational modifications, emphasize the possibilities for fine-tuning the PABP metabolic network.
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Affiliation(s)
- Dixie J Goss
- Chemistry Department, Hunter College CUNY, New York, NY, USA.
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22
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Konopka CA, Locke MN, Gallagher PS, Pham N, Hart MP, Walker CJ, Gitler AD, Gardner RG. A yeast model for polyalanine-expansion aggregation and toxicity. Mol Biol Cell 2011; 22:1971-84. [PMID: 21508314 PMCID: PMC3113764 DOI: 10.1091/mbc.e11-01-0037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Polyalanine expansions can result in aggregation and cause cytotoxicity. We have created the first yeast model of polyalanine-expansion aggregation and toxicity using the poly(Ade)-binding protein Pab1. Nine human disorders result from the toxic accumulation and aggregation of proteins with expansions in their endogenous polyalanine (polyA) tracts. Given the prevalence of polyA tracts in eukaryotic proteomes, we wanted to understand the generality of polyA-expansion cytotoxicity by using yeast as a model organism. In our initial case, we expanded the polyA tract within the native yeast poly(Adenine)-binding protein Pab1 from 8A to 13A, 15A, 17A, and 20A. These expansions resulted in increasing formation of Pab1 inclusions, insolubility, and cytotoxicity that correlated with the length of the polyA expansion. Pab1 binds mRNA as part of its normal function, and disrupting RNA binding or altering cytoplasmic mRNA levels suppressed the cytotoxicity of 17A-expanded Pab1, indicating a requisite role for mRNA in Pab1 polyA-expansion toxicity. Surprisingly, neither manipulation suppressed the cytotoxicity of 20A-expanded Pab1. Thus longer expansions may have a different mechanism for toxicity. We think that this difference underscores the potential need to examine the cytotoxic mechanisms of both long and short expansions in models of expansion disorders.
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23
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Yángüez E, Nieto A. So similar, yet so different: selective translation of capped and polyadenylated viral mRNAs in the influenza virus infected cell. Virus Res 2010; 156:1-12. [PMID: 21195735 DOI: 10.1016/j.virusres.2010.12.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 12/22/2010] [Accepted: 12/22/2010] [Indexed: 02/05/2023]
Abstract
Influenza virus is included among the Orthomyxoviridae family and it is a major public health problem causing annual mortality worldwide. Viral mRNAs bear short capped oligonucleotide sequences at their 5'-ends, acquired from host cell pre-mRNAs during viral transcription, and are polyadenylated at their 3'-end. Therefore, viral and cellular mRNAs are undistinguishable from a structural point of view. However, selective translation of viral proteins occurs upon infection, while initiation and elongation steps of cellular mRNA translation are efficiently inhibited. Viruses do not possess the complex machinery required to translate their mRNAs and are then obliged to compete for host-cell factors and manipulate the translation apparatus to their own benefit. Thus, the understanding of the processes that govern viral translation could facilitate the finding of possible targets for anti viral interventions. In the present review, we will point out the mechanisms by which influenza virus takes control of the host-cell protein synthesis machinery to ensure the production of new viral particles. First, we will discuss the mechanisms by which the virus counteracts the anti viral translation repression induced in the infected cell. Next, we will focus on the shut-off of cellular protein synthesis and the specific requirements for the eIF4F complex on influenza mRNA translation. Finally, we will discuss the role of different cellular and viral proteins in the selective translation of viral messengers in the infected cell and we will summarize the proposed mechanisms for the recruitment of cellular translational machinery to the viral mRNAs.
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Affiliation(s)
- Emilio Yángüez
- Centro Nacional de Biotecnología, C.S.I.C., Darwin 3, Cantoblanco, 28049 Madrid, Spain
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24
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Yanagiya A, Delbes G, Svitkin YV, Robaire B, Sonenberg N. The poly(A)-binding protein partner Paip2a controls translation during late spermiogenesis in mice. J Clin Invest 2010; 120:3389-400. [PMID: 20739757 DOI: 10.1172/jci43350] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 07/14/2010] [Indexed: 11/17/2022] Open
Abstract
Translational control plays a key role in late spermiogenesis. A number of mRNAs encoding proteins required for late spermiogenesis are expressed in early spermatids but are stored as translationally inactive messenger ribonucleoprotein particles (mRNPs). The translation of these mRNAs is associated with shortening of their poly(A) tail in late spermiogenesis. Poly(A)-binding protein (Pabp) plays an important role in mRNA stabilization and translation. Three Pabp-interacting proteins, Paip1, Paip2a, and Paip2b, have been described. Paip2a is expressed in late spermatids. To investigate the role of Paip2 in spermiogenesis, we generated mice with knockout of either Paip2a or Paip2b and double-KO (DKO) mice lacking both Paip2a and Paip2b. Paip2a-KO and Paip2a/Paip2b-DKO mice exhibited male infertility. Translation of several mRNAs encoding proteins essential to male germ cell development was inhibited in late spermiogenesis in Paip2a/Paip2b-DKO mice, resulting in defective elongated spermatids. Inhibition of translation in Paip2a/Paip2b-DKO mice was caused by aberrant increased expression of Pabp, which impaired the interaction between eukaryotic initiation factor 4E (eIF4E) and the cap structure at the 5' end of the mRNA. We therefore propose a model whereby efficient mRNA translation in late spermiogenesis occurs at an optimal concentration of Pabp, a condition not fulfilled in Paip2a/Paip2b-DKO mice.
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Affiliation(s)
- Akiko Yanagiya
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada
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25
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Beerens N, Kjems J. Circularization of the HIV-1 genome facilitates strand transfer during reverse transcription. RNA (NEW YORK, N.Y.) 2010; 16:1226-35. [PMID: 20430859 PMCID: PMC2874174 DOI: 10.1261/rna.2039610] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 02/23/2010] [Indexed: 05/18/2023]
Abstract
Two obligatory DNA strand transfers take place during reverse transcription of a retroviral RNA genome. The first strand transfer involves a jump from the 5' to the 3' terminal repeat (R) region positioned at each end of the viral genome. The process depends on base pairing between the cDNA synthesized from the 5' R region and the 3' R RNA. The tertiary conformation of the viral RNA genome may facilitate strand transfer by juxtaposing the 5' R and 3' R sequences that are 9 kb apart in the linear sequence. In this study, RNA sequences involved in an interaction between the 5' and 3' ends of the HIV-1 genome were mapped by mutational analysis. This interaction appears to be mediated mainly by a sequence in the extreme 3' end of the viral genome and in the gag open reading frame. Mutation of 3' R sequences was found to inhibit the 5'-3' interaction, which could be restored by a complementary mutation in the 5' gag region. Furthermore, we find that circularization of the HIV-1 genome does not affect the initiation of reverse transcription, but stimulates the first strand transfer during reverse transcription in vitro, underscoring the functional importance of the interaction.
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Affiliation(s)
- Nancy Beerens
- Department of Molecular Biology, Aarhus University, DK-8000 Aarhus C, Denmark
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26
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Affiliation(s)
- Sean R Carmody
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 38232, USA
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Polacek C, Friebe P, Harris E. Poly(A)-binding protein binds to the non-polyadenylated 3' untranslated region of dengue virus and modulates translation efficiency. J Gen Virol 2009; 90:687-692. [PMID: 19218215 DOI: 10.1099/vir.0.007021-0] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Poly(A)-binding protein (PABP) is a key player in mRNA circularization and translation initiation of polyadenylated mRNAs. It simultaneously binds the 3' poly(A) tail of an mRNA and eukaryotic initiation factor 4G (eIF4G), which forms part of the translation initiation complex assembling at the 5'end, thus circularizing the RNA molecule and enhancing translation initiation. Here, we report the binding of PABP to the non-polyadenylated 3'end of dengue virus (DENV) RNA. PABP binds the DENV 3' untranslated region (3'UTR) internally, upstream of the conserved 3'stem-loop near the two dumb-bell structures, and can be displaced by poly(A) RNA. The PABP-specific translation inhibitor PABP-interacting protein 2 (Paip2) interferes with the DENV 3'UTR-PABP interaction, and in vitro translation of DENV reporter RNAs in baby hamster kidney cell extracts is inhibited by Paip2 in a dose-dependent manner. Our findings show an expanded translation mechanism for PABP, binding to a viral RNA lacking a terminal poly(A) tail.
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Affiliation(s)
- Charlotta Polacek
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, 1 Barker Hall, Berkeley, CA 94720-7354, USA
| | - Peter Friebe
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, 1 Barker Hall, Berkeley, CA 94720-7354, USA
| | - Eva Harris
- Division of Infectious Diseases, School of Public Health, University of California, Berkeley, 1 Barker Hall, Berkeley, CA 94720-7354, USA
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Galicia-Vázquez G, Lindqvist L, Wang X, Harvey I, Liu J, Pelletier J. High-throughput assays probing protein–RNA interactions of eukaryotic translation initiation factors. Anal Biochem 2009; 384:180-8. [DOI: 10.1016/j.ab.2008.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/21/2008] [Accepted: 09/22/2008] [Indexed: 11/26/2022]
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Duning K, Buck F, Barnekow A, Kremerskothen J. SYNCRIP, a component of dendritically localized mRNPs, binds to the translation regulator BC200 RNA. J Neurochem 2008; 105:351-9. [DOI: 10.1111/j.1471-4159.2007.05138.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Herr JC, Chertihin O, Digilio L, Jha KN, Vemuganti S, Flickinger CJ. Distribution of RNA binding protein MOEP19 in the oocyte cortex and early embryo indicates pre-patterning related to blastomere polarity and trophectoderm specification. Dev Biol 2008; 314:300-16. [PMID: 18191828 PMCID: PMC2271035 DOI: 10.1016/j.ydbio.2007.11.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 11/20/2007] [Accepted: 11/21/2007] [Indexed: 11/24/2022]
Abstract
We report the cloning and characterization of MOEP19, a novel 19 kDa RNA binding protein that marks a defined cortical cytoplasmic domain in oocytes and provides evidence of mammalian oocyte polarity and a form of pre-patterning that persists in zygotes and early embryos through the morula stage. MOEP19 contains a eukaryotic type KH-domain, typical of the KH-domain type I superfamily of RNA binding proteins, and both recombinant and native MOEP19 bind polynucleotides. By immunofluorescence, MOEP19 protein was first detected in primary follicles throughout the ooplasm. As oocytes expanded in size during oogenesis, MOEP19 increased in concentration. MOEP19 localized in the ovulated egg and early zygote as a symmetrical spherical cortical domain underlying the oolemma, deep to the zone of cortical granules. MOEP19 remained restricted to a cortical cytoplasmic crescent in blastomeres of 2-, 4- and 8-cell embryos. The MOEP19 domain was absent in regions underlying cell contacts. In morulae, the MOEP19 domain was found at the apex of outer, polarized blastomeres but was undetectable in blastomeres of the inner cell mass. In early blastocysts, MOEP19 localized in both mural and polar trophectoderm and a subset of embryos showed inner cell mass localization. MOEP19 concentration dramatically declined in late blastocysts. When blastomeres of 4- to 8-cell stages were dissociated, the polarized MOEP19 domain assumed a symmetrically spherical localization, while overnight culture of dissociated blastomeres resulted in formation of re-aggregated embryos in which polarity of the MOEP19 domain was re-established at the blastomere apices. MOEP19 showed no evidence of translation in ovulated eggs, indicating that MOEP19 is a maternal effect gene. The persistence during early development of the MOEP19 cortical oocyte domain as a cortical crescent in blastomers suggests an intrinsic pre-patterning in the egg that is related to the apical-basolateral polarity of the embryo. Although the RNAs bound to MOEP19 are presently unknown, we predict that the MOEP19 domain directs RNAs essential for normal embryonic development to specific locations in the oocyte and early embryo.
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Affiliation(s)
- John C Herr
- Center for Research in Contraceptive and Reproductive Health, Department of Cell Biology, P.O. Box 800732, University of Virginia Health System, Charlottesville, VA 22908, USA.
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Simón E, Séraphin B. A specific role for the C-terminal region of the Poly(A)-binding protein in mRNA decay. Nucleic Acids Res 2007; 35:6017-28. [PMID: 17766253 PMCID: PMC2094065 DOI: 10.1093/nar/gkm452] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
mRNA poly(A) tails affect translation, mRNA export and mRNA stability, with translation initiation involving a direct interaction between eIF4G and the poly(A)-binding protein Pab1. The latter factor contains four RNA recognition motifs followed by a C-terminal region composed of a linker and a PABC domain. We show here that yeast mutants lacking the C-terminal domains of Pab1 display specific synthetic interactions with mutants in the 5′-3′ mRNA decay pathway. Moreover, these mutations impair mRNA decay in vivo without significantly affecting mRNA export or translation. Inhibition of mRNA decay occurs through slowed deadenylation. In vitro analyses demonstrate that removal of the Pab1 linker domain directly interferes with the ability of the Pop2–Ccr4 complex to deadenylate the Pab1-bound poly(A). Binding assays demonstrate that this results from a modulation of poly(A) packaging by the Pab1 linker region. Overall, our results demonstrate a direct involvement of Pab1 in mRNA decay and reveal the modular nature of this factor, with different domains affecting various cellular processes. These data suggest new models involving the modulation of poly(A) packaging by Pab1 to control mRNA decay.
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Affiliation(s)
| | - Bertrand Séraphin
- *To whom correspondence should be addressed. +33 1 69 82 38 84+33 1 69 82 38 77
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32
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Cheng S, Gallie DR. eIF4G, eIFiso4G, and eIF4B bind the poly(A)-binding protein through overlapping sites within the RNA recognition motif domains. J Biol Chem 2007; 282:25247-58. [PMID: 17606619 DOI: 10.1074/jbc.m702193200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The poly(A)-binding protein (PABP), a protein that contains four conserved RNA recognition motifs (RRM1-4) and a C-terminal domain, is expressed throughout the eukaryotic kingdom and promotes translation through physical and functional interactions with eukaryotic initiation factor (eIF) 4G and eIF4B. Two highly divergent isoforms of eIF4G, known as eIF4G and eIFiso4G, are expressed in plants. As little is known about how PABP can interact with RNA and three distinct translation initiation factors in plants, the RNA binding specificity and organization of the protein interaction domains in wheat PABP was investigated. Wheat PABP differs from animal PABP in that its RRM1 does not bind RNA as an individual domain and that RRM 2, 3, and 4 exhibit different RNA binding specificities to non-poly(A) sequences. The PABP interaction domains for eIF4G and eIFiso4G were distinct despite the functional similarity between the eIF4G proteins. A single interaction domain for eIF4G is present in the RRM1 of PABP, whereas eIFiso4G interacts at two sites, i.e. one within RRM1-2 and the second within RRM3-4. The eIFiso4G binding site in RRM1-2 mapped to a 36-amino acid region encompassing the C-terminal end of RRM1, the linker region, and the N-terminal end of RRM2, whereas the second site in RRM3-4 was more complex. A single interaction domain for eIF4B is present within a 32-amino acid region representing the C-terminal end of RRM1 of PABP that overlaps with the N-proximal eIFiso4G interaction domain. eIF4B and eIFiso4G exhibited competitive binding to PABP, supporting the overlapping nature of their interaction domains. These results support the notion that eIF4G, eIFiso4G, and eIF4B interact with distinct molecules of PABP to increase the stability of the interaction between the termini of an mRNA.
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Affiliation(s)
- Shijun Cheng
- Department of Biochemistry, University of California, Riverside, California 92521-0129, USA
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33
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Derry MC, Yanagiya A, Martineau Y, Sonenberg N. Regulation of poly(A)-binding protein through PABP-interacting proteins. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2007; 71:537-43. [PMID: 17381337 DOI: 10.1101/sqb.2006.71.061] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Translation initiation requires the participation of eukaryotic translation initiation factors (eIFs). The poly(A)-binding protein (PABP) is thought to stimulate translation by promoting mRNA circularization through simultaneous interactions with eIF4G and the 3' poly(A) tail. PABP activity is regulated by the PABP-interacting proteins (Paips), a family of proteins consisting of Paip1, a translational stimulator, and Paip2A and Paip2B, two translational inhibitors. Paip2A controls PABP homeostasis via ubiquitination. When the cellular concentration of PABP is reduced, Paip2A becomes ubiquitinated and degraded, resulting in the relief of PABP repression. Paip1 interacts with eIF4A and eIF3, which promotes translation. The regulation of PABP activity by Paips represents the first known mechanism for controlling PABP, adding a new layer to the existing knowledge of PABP function.
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Affiliation(s)
- M C Derry
- Department of Biochemistry and McGill Cancer Centre, McGill University, Montréal, Québec, Canada
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34
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Stefanizzi I, Cañete-Soler R. Coregulation of light neurofilament mRNA by poly(A)-binding protein and aldolase C: Implications for neurodegeneration. Brain Res 2007; 1139:15-28. [PMID: 17276415 DOI: 10.1016/j.brainres.2006.12.092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/14/2006] [Accepted: 12/31/2006] [Indexed: 11/16/2022]
Abstract
The multifunctional proteins aldolase C and poly (A)-binding protein (PABP) undergo competitive interactions in cells coexpressing aldolase C and NF-L. A specific in vivo interaction between aldolase C and NF-L mRNA had been localized to a 68 nt segment of the transcript spanning the translation termination signal. It is shown here that the poly (A)-binding protein (PABP) binds the body of the NF-L transcript and increases its levels of expression when an excess of PABP is transiently provided in trans. Immunoprecipitation of PABP-associated ribonucleoprotein complexes of human spinal cord pulls down the dimeric form of aldolase C suggesting that their co-regulation of NF-L expression could be linked to the oligomerization status of aldolase C. An ex vivo model of mRNA decay has assessed mechanisms whereby aldolase C and PABP control NF-L expression. This model shows that aldolase C is a zinc-activated ribonuclease that cleaves the transcript at sites closed to the end-terminal structures. Immunological and biochemical depletion of endogenous PABP increases the instability of the transcript suggesting that PABP shields the NF-L mRNA from aldolase attack. An in vitro model shows that a mutant NF-L 68, in which the 45 nt of proximal 3'-UTR is replaced with unrelated sequence, is not degraded by aldolase C. Taken together, the findings might have important consequences for understanding causal mechanisms underlying neurodegeneration.
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Affiliation(s)
- Ida Stefanizzi
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, 608 Stellar Chance, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
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35
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Patel GP, Bag J. IMP1 interacts with poly(A)-binding protein (PABP) and the autoregulatory translational control element of PABP-mRNA through the KH III-IV domain. FEBS J 2006; 273:5678-90. [PMID: 17212783 DOI: 10.1111/j.1742-4658.2006.05556.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Repression of poly(A)-binding protein (PABP) mRNA translation involves the formation of a heterotrimeric ribonucleoprotein complex by the binding of PABP, insulin-like growth factor II mRNA binding protein-1 (IMP1) and the unr gene encoded polypeptide (UNR) to the adenine-rich autoregulatory sequence (ARS) located at the 5' untranslated region of the PABP-mRNA. In this report, we have further characterized the interaction between PABP and IMP1 with the ARS at the molecular level. The dissociation constants of PABP and IMP1 for binding to the ARS RNA were determined to be 2.3 nM and 5.9 nM, respectively. Both PABP and IMP1 interact with each other, regardless of the presence of the ARS, through the conserved C-terminal PABP-C and K-homology (KH) III-IV domains, respectively. Interaction of PABP with the ARS requires at least three out of its four RNA-binding domains, whereas KH III-IV domain of IMP1 is necessary and sufficient for binding to the ARS. In addition, the strongest binding site for both PABP and IMP1 on the ARS was determined to be within the 22 nucleotide-long CCCAAAAAAAUUUACAAAAAA sequence located at the 3' end of the ARS. Results of our analysis suggest that both protein x protein and protein x RNA interactions are involved in forming a stable ribonucleoprotein complex at the ARS of PABP mRNA.
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Affiliation(s)
- Gopal P Patel
- Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada
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36
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Dizin E, Gressier C, Magnard C, Ray H, Décimo D, Ohlmann T, Dalla Venezia N. BRCA1 Interacts with Poly(A)-binding Protein. J Biol Chem 2006; 281:24236-46. [PMID: 16782705 DOI: 10.1074/jbc.m602176200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BRCA1 has been implicated in a number of cellular processes, including transcription regulation, DNA damage repair, cell cycle control, and apoptosis. We identified poly(A)-binding protein 1 (PABP) as a novel BRCA1-interacting protein in a yeast two-hybrid screen and confirmed the interaction by in vitro assays and coimmunoprecipitation in mammalian cells. Endogenous interaction between BRCA1 and PABP was also observed. This interaction was abolished by BRCA1 cancer-associated mutations, suggesting that it may be physiologically relevant. Deletion mapping demonstrated that the RNA recognition motifs 1-4 region of PABP is required to mediate the interaction with BRCA1. To understand the biological function of the BRCA1-PABP complex, we sought to determine whether BRCA1 is a modulator of translation. We showed here that inhibition of endogenous BRCA1 using a small interfering RNA-based approach decreased protein synthesis. Conversely, overexpression of BRCA1 activated translation. Using a RNA transfection approach, we clearly showed that BRCA1 modulates translation, independently of any transcriptional activity. The data presented here suggest that BRCA1 modulates protein synthesis via its interaction with PABP, providing a novel mechanism by which BRCA1 may exert its tumor suppressor function.
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Affiliation(s)
- Eva Dizin
- CNRS UMR 5201, Laboratoire de Génétique Moléculaire, Signalisation et Cancer, Université Claude Bernard Lyon I, Facultéde Médecine Rockefeller, 8 Avenue Rockefeller, 69373 Lyon cedex 08, France
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37
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Svitkin YV, Sonenberg N. Translational control by the poly(A) binding protein: A check for mRNA integrity. Mol Biol 2006. [DOI: 10.1134/s0026893306040133] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Law MJ, Rice AJ, Lin P, Laird-Offringa IA. The role of RNA structure in the interaction of U1A protein with U1 hairpin II RNA. RNA (NEW YORK, N.Y.) 2006; 12:1168-78. [PMID: 16738410 PMCID: PMC1484440 DOI: 10.1261/rna.75206] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The N-terminal RNA Recognition Motif (RRM1) of the spliceosomal protein U1A interacting with its target U1 hairpin II (U1hpII) has been used as a paradigm for RRM-containing proteins interacting with their RNA targets. U1A binds to U1hpII via direct interactions with a 7-nucleotide (nt) consensus binding sequence at the 5' end of a 10-nt loop, and via hydrogen bonds with the closing C-G base pair at the top of the RNA stem. Using surface plasmon resonance (Biacore), we have examined the role of structural features of U1hpII in binding to U1A RRM1. Mutational analysis of the closing base pair suggests it plays a minor role in binding and mainly prevents "breathing" of the loop. Lengthening the stem and nontarget part of the loop suggests that the increased negative charge of the RNA might slightly aid association. However, this is offset by an increase in dissociation, which may be caused by attraction of the RRM to nontarget parts of the RNA. Studies of a single stranded target and RNAs with untethered loops indicate that structure is not very relevant for association but is important for complex stability. In particular, breaking the link between the stem and the 5' side of the loop greatly increases complex dissociation, presumably by hindering simultaneous contacts between the RRM and stem and loop nucleotides. While binding of U1A to a single stranded target is much weaker than to U1hpII, it occurs with nanomolar affinity, supporting recent evidence that binding of unstructured RNA by U1A has physiological significance.
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Affiliation(s)
- Michael J Law
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9176, USA
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39
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Wang H, Iacoangeli A, Lin D, Williams K, Denman RB, Hellen CUT, Tiedge H. Dendritic BC1 RNA in translational control mechanisms. ACTA ACUST UNITED AC 2006; 171:811-21. [PMID: 16330711 PMCID: PMC1828541 DOI: 10.1083/jcb.200506006] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translational control at the synapse is thought to be a key determinant of neuronal plasticity. How is such control implemented? We report that small untranslated BC1 RNA is a specific effector of translational control both in vitro and in vivo. BC1 RNA, expressed in neurons and germ cells, inhibits a rate-limiting step in the assembly of translation initiation complexes. A translational repression element is contained within the unique 3' domain of BC1 RNA. Interactions of this domain with eukaryotic initiation factor 4A and poly(A) binding protein mediate repression, indicating that the 3' BC1 domain targets a functional interaction between these factors. In contrast, interactions of BC1 RNA with the fragile X mental retardation protein could not be documented. Thus, BC1 RNA modulates translation-dependent processes in neurons and germs cells by directly interacting with translation initiation factors.
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Affiliation(s)
- Huidong Wang
- Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, Brooklyn, NY 11203, USA
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40
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Ma S, Musa T, Bag J. Reduced stability of mitogen-activated protein kinase kinase-2 mRNA and phosphorylation of poly(A)-binding protein (PABP) in cells overexpressing PABP. J Biol Chem 2005; 281:3145-56. [PMID: 16332685 DOI: 10.1074/jbc.m508937200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The poly(A)-binding protein (PABP) is an important regulator of mRNA translation and stability. The cellular level of PABP is controlled by regulating its mRNA translation by a feedback mechanism. The important aspect of this mechanism is that PABP binds to an adenosine-rich cis-element at the 5'-untranslated region of its own mRNA and inhibits its translation. To assess the importance of controlling the PABP level, we studied the effect of PABP overexpression on the transcription profile using the microarray technique. In PABP-overexpressing cells, 19 mRNAs showed a reduction in cellular levels due to reduced mRNA stability, and one showed an increase due to increased mRNA stability. Among these mRNAs, the MKK-2 mRNA encodes the protein kinase activator of ERK1/2 kinase, which is involved in the phosphorylation of eukaryotic initiation factor (eIF) 4E. As a result, mRNA translation may be regulated by the cellular level of MKK-2. In this study, we show that the abundance of the MKK-2 polypeptide is reduced in PABP-overexpressing cells. In these cells, the levels of phosphorylated PABP, eIF4E, and ERK2 are also reduced. Treatment of HeLa cells with the MKK-2 inhibitor U0126 reduced PABP phosphorylation, suggesting that the phosphorylation of PABP is mediated by the MKK-2/ERK signaling pathway. Thus, a novel signaling pathway involving MKK-2 and ERK1/2 may down-regulate the activity of PABP and eIF4E by controlling their phosphorylation and compensates for the effect of excess cellular PABP.
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Affiliation(s)
- Shuhua Ma
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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41
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Silvestri LS, Parilla JM, Morasco BJ, Ogram SA, Flanegan JB. Relationship between poliovirus negative-strand RNA synthesis and the length of the 3' poly(A) tail. Virology 2005; 345:509-19. [PMID: 16297425 DOI: 10.1016/j.virol.2005.10.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Revised: 10/07/2005] [Accepted: 10/18/2005] [Indexed: 10/25/2022]
Abstract
The precise relationship between the length of the 3' poly(A) tail and the replication and infectivity of poliovirus RNA was examined in this study. With both poly(A)(11) and poly(A)(12) RNAs, negative-strand synthesis was 1-3% of the level observed with poly(A)(80) RNA. In contrast, increasing the length of the poly(A) tail from (A)(12) to (A)(13) resulted in about a ten-fold increase in negative-strand synthesis. This increase continued with each successive increase in poly(A) tail length. With poly(A)(20) RNA, RNA synthesis approached the level observed with poly(A)(80) RNA. A similar relationship was observed between poly(A) tail length and the infectivity of the viral RNA. A replication model is described which suggests that viral RNA replication is dependent on a poly(A) tail that is long enough to bind poly(A) binding protein and to act as a template for VPg uridylylation and negative-strand initiation.
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Affiliation(s)
- Lynn S Silvestri
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, 32610-0245, USA
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42
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Mullin C, Duning K, Barnekow A, Richter D, Kremerskothen J, Mohr E. Interaction of rat poly(A)-binding protein with poly(A)- and non-poly(A) sequences is preferentially mediated by RNA recognition motifs 3+4. FEBS Lett 2004; 576:437-41. [PMID: 15498576 DOI: 10.1016/j.febslet.2004.09.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 09/20/2004] [Indexed: 11/25/2022]
Abstract
Vasopressin (VP) mRNA and the non-coding BC200 RNA are sorted to neuronal dendrites. Among proteins interacting specifically with both RNAs is the multifunctional poly(A)-binding protein (PABP) consisting of four RNA recognition motifs (RRMs) and a C-terminal auxiliary domain. The protein/RNA interaction studies presented here reveal that PABPs association with VP- and BC200 RNA is exclusively mediated by RRMs 3+4. Quantitative binding studies with PABP deletion mutants demonstrate preferential binding of RRMs 3+4 even to poly(A)-homopolymers, while RRMs 1+2 exhibit a lower affinity for those sequences. An optimal interaction with both poly(A)- and non-poly(A) sequences is only achieved by full-size PABP.
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Affiliation(s)
- Carola Mullin
- Department for Cell Biochemistry and Clinical Neurobiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
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43
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Dower K, Kuperwasser N, Merrikh H, Rosbash M. A synthetic A tail rescues yeast nuclear accumulation of a ribozyme-terminated transcript. RNA (NEW YORK, N.Y.) 2004; 10:1888-99. [PMID: 15547135 PMCID: PMC1370677 DOI: 10.1261/rna.7166704] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To investigate the role of 3' end formation in yeast mRNA export, we replaced the mRNA cleavage and polyadenylation signal with a self-cleaving hammerhead ribozyme element. The resulting RNA is unadenylated and accumulates near its site of synthesis. Nonetheless, a significant fraction of this RNA reaches the cytoplasm. Nuclear accumulation was relieved by insertion of a stretch of DNA-encoded adenosine residues immediately upstream of the ribozyme element (a synthetic A tail). This indicates that a 3' stretch of adenosines can promote export, independently of cleavage and polyadenylation. We further show that a synthetic A tail-containing RNA is unaffected in 3' end formation mutant strains, in which a normally cleaved and polyadenylated RNA accumulates within nuclei. Our results support a model in which a polyA tail contributes to efficient mRNA progression away from the gene, most likely through the action of the yeast polyA-tail binding protein Pab1p.
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MESH Headings
- Base Sequence
- Cell Nucleus/metabolism
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- In Situ Hybridization, Fluorescence
- Models, Biological
- Mutation
- Poly A/chemistry
- Poly A/genetics
- Poly A/metabolism
- Poly(A)-Binding Proteins/genetics
- Poly(A)-Binding Proteins/metabolism
- RNA, Catalytic/metabolism
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins/genetics
- Saccharomyces cerevisiae Proteins/metabolism
- Transcription, Genetic
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Affiliation(s)
- Ken Dower
- Howard Hughes Medical Institute, Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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44
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Kühn U, Wahle E. Structure and function of poly(A) binding proteins. ACTA ACUST UNITED AC 2004; 1678:67-84. [PMID: 15157733 DOI: 10.1016/j.bbaexp.2004.03.008] [Citation(s) in RCA: 246] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 03/30/2004] [Accepted: 03/31/2004] [Indexed: 01/01/2023]
Abstract
Poly (A) tails are found at the 3' ends of almost all eukaryotic mRNAs. They are bound by two different poly (A) binding proteins, PABPC in the cytoplasm and PABPN1 in the nucleus. PABPC functions in the initiation of translation and in the regulation of mRNA decay. In both functions, an interaction with the m7G cap at the 5' end of the message plays an important role. PABPN1 is involved in the synthesis of poly (A) tails, increasing the processivity of poly (A) polymerase and contributing to defining the length of a newly synthesized poly (A) tail.
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Affiliation(s)
- Uwe Kühn
- Institut für Biochemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Stasse. 3, D-06120 Halle, Germany
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45
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Sladic RT, Lagnado CA, Bagley CJ, Goodall GJ. Human PABP binds AU-rich RNA via RNA-binding domains 3 and 4. ACTA ACUST UNITED AC 2004; 271:450-7. [PMID: 14717712 DOI: 10.1046/j.1432-1033.2003.03945.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Poly(A) binding protein (PABP) binds mRNA poly(A) tails and affects mRNA stability and translation. We show here that there is little free PABP in NIH3T3 cells, with the vast majority complexed with RNA. We found that PABP in NIH3T3 cytoplasmic lysates and recombinant human PABP can bind to AU-rich RNA with high affinity. Human PABP bound an AU-rich RNA with Kd in the nm range, which was only sixfold weaker than the affinity for oligo(A) RNA. Truncated PABP containing RNA recognition motif domains 3 and 4 retained binding to both AU-rich and oligo(A) RNA, whereas a truncated PABP containing RNA recognition motif domains 1 and 2 was highly selective for oligo(A) RNA. The inducible PABP, iPABP, was found to be even less discriminating than PABP in RNA binding, with affinities for AU-rich and oligo(A) RNAs differing by only twofold. These data suggest that iPABP and PABP may in some situations interact with other RNA regions in addition to the poly(A) tail.
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Affiliation(s)
- Rosemary T Sladic
- Division of Human Immunology and Hanson Institute, Institute of Medical and Veterinary Science, Adelaide, Australia
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46
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Burgui I, Aragón T, Ortín J, Nieto A. PABP1 and eIF4GI associate with influenza virus NS1 protein in viral mRNA translation initiation complexes. J Gen Virol 2004; 84:3263-3274. [PMID: 14645908 DOI: 10.1099/vir.0.19487-0] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
It has previously been shown that influenza virus NS1 protein enhances the translation of viral but not cellular mRNAs. This enhancement occurs by increasing the rate of translation initiation and requires the 5'UTR sequence, common to all viral mRNAs. In agreement with these findings, we show here that viral mRNAs, but not cellular mRNAs, are associated with NS1 during virus infection. We have previously reported that NS1 interacts with the translation initiation factor eIF4GI, next to its poly(A)-binding protein 1 (PABP1)-interacting domain and that NS1 and eIF4GI are associated in influenza virus-infected cells. Here we show that NS1, although capable of binding poly(A), does not compete with PABP1 for association with eIF4GI and, furthermore, that NS1 and PABP1 interact both in vivo and in vitro in an RNA-independent manner. The interaction maps between residues 365 and 535 in PABP1 and between residues 1 and 81 in NS1. These mapping studies, together with those previously reported for NS1-eIF4GI and PABP1-eIF4GI interactions, imply that the binding of all three proteins would be compatible. Collectively, these and previously published data suggest that NS1 interactions with eIF4GI and PABP1, as well as with viral mRNAs, could promote the specific recruitment of 43S complexes to the viral mRNAs.
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Affiliation(s)
- Idoia Burgui
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Tomás Aragón
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Juan Ortín
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Amelia Nieto
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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47
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Melo EO, de Melo Neto OP, Martins de Sá C. Adenosine-rich elements present in the 5'-untranslated region of PABP mRNA can selectively reduce the abundance and translation of CAT mRNAs in vivo. FEBS Lett 2003; 546:329-34. [PMID: 12832063 DOI: 10.1016/s0014-5793(03)00620-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The poly(A)-binding protein (PABP) is a highly conserved eukaryotic protein whose synthesis is regulated at the post-transcriptional level. The binding of PABP to the poly(A)-rich element found in the 5'-untranslated region (5'UTR) of PABP mRNA specifically inhibits its own translation. In this report, we show that similar adenosine-rich elements in the 5'UTR of the chloramphenicol acetyl-transferase (CAT) gene can significantly reduce the reporter mRNA abundance and translation in human 293 cells. The reduction in mRNA level, but not CAT expression, is dependent on the size of the 5'UTR poly(A) element. Furthermore, one 5'UTR-tethered PABP molecule is enough to inhibit CAT expression without affecting its mRNA level. We propose that the control of PABP synthesis may involve mRNA decay and the repression of translation.
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Affiliation(s)
- Eduardo O Melo
- Departamento de Biologia Celular, Universidade de Brasília, Asa Norte, Brasília, DF 70910-900, Brazil.
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Kahvejian A, Roy G, Sonenberg N. The mRNA closed-loop model: the function of PABP and PABP-interacting proteins in mRNA translation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2003; 66:293-300. [PMID: 12762031 DOI: 10.1101/sqb.2001.66.293] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- A Kahvejian
- Department of Biochemistry, McGill Cancer Center, McGill University, Montréal, Québec, Canada
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Kühn U, Nemeth A, Meyer S, Wahle E. The RNA binding domains of the nuclear poly(A)-binding protein. J Biol Chem 2003; 278:16916-25. [PMID: 12637556 DOI: 10.1074/jbc.m209886200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nuclear poly(A)-binding protein (PABPN1) is involved in the synthesis of the mRNA poly(A) tails in most eukaryotes. We report that the protein contains two RNA binding domains, a ribonucleoprotein-type RNA binding domain (RNP domain) located approximately in the middle of the protein sequence and an arginine-rich C-terminal domain. The C-terminal domain also promotes self-association of PABPN1 and moderately cooperative binding to RNA. Whereas the isolated RNP domain binds specifically to poly(A), the isolated C-terminal domain binds non-specifically to RNA and other polyanions. Despite this nonspecific RNA binding by the C-terminal domain, selection experiments show that adenosine residues throughout the entire minimal binding site of approximately 11 nucleotides are recognized specifically. UV-induced cross-links with oligo(A) carrying photoactivatable nucleotides at different positions all map to the RNP domain, suggesting that most or all of the base-specific contacts are made by the RNP domain, whereas the C-terminal domain may contribute nonspecific contacts, conceivably to the same nucleotides. Asymmetric dimethylation of 13 arginine residues in the C-terminal domain has no detectable influence on the interaction of the protein with RNA. The N-terminal domain of PABPN1 is not required for RNA binding but is essential for the stimulation of poly(A) polymerase.
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Affiliation(s)
- Uwe Kühn
- Institut für Biochemie, Martin-Luther-Universität Halle, 06099 Halle, Germany
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Mohr E, Richter D. Molecular determinants and physiological relevance of extrasomatic RNA localization in neurons. Front Neuroendocrinol 2003; 24:128-39. [PMID: 12763001 DOI: 10.1016/s0091-3022(03)00011-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Specific sorting of mRNA molecules to subcellular microdomains is an evolutionarily conserved mechanism by which the polarized nature of eukayotic cells may be established and maintained. The molecular composition of the RNA localization machinery is complex. Sequence motifs within RNA molecules to be transported, called cis-acting elements, and proteins, referred to as trans-acting factors, are essential components. Transport of the resulting ribonucleoprotein complexes to distinct cytoplasmic regions occurs along the cytoskeletal network. The pathway is observed in organisms as diverse as yeast and human and it plays a critical role in development and cell differentiation. Moreover, RNA localization takes place in differentiated cell types including neurons. There is ample evidence to suggest that sorting of defined mRNA species to the neurites of nerve cells and on-site translation has an impact on various aspects of nerve cell biology.
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Affiliation(s)
- Evita Mohr
- Institute for Cell Biochemistry and Clinical Neurobiology, University Clinic Hamburg-Eppendorf, Martinistr 52, D-20246, Hamburg, Germany.
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