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Kurosaki T, Rambout X, Maquat LE. FMRP-mediated spatial regulation of physiologic NMD targets in neuronal cells. Genome Biol 2024; 25:31. [PMID: 38263082 PMCID: PMC10804635 DOI: 10.1186/s13059-023-03146-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
In non-polarized cells, nonsense-mediated mRNA decay (NMD) generally begins during the translation of newly synthesized mRNAs after the mRNAs are exported to the cytoplasm. Binding of the FMRP translational repressor to UPF1 on NMD targets mainly inhibits NMD. However, in polarized cells like neurons, FMRP additionally localizes mRNAs to cellular projections. Here, we review the literature and evaluate available transcriptomic data to conclude that, in neurons, the translation of physiologic NMD targets bound by FMRP is partially inhibited until the mRNAs localize to projections. There, FMRP displacement in response to signaling induces a burst in protein synthesis followed by rapid mRNA decay.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA.
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2
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Rademacher DJ, Bello AI, May JP. CASC3 Biomolecular Condensates Restrict Turnip Crinkle Virus by Limiting Host Factor Availability. J Mol Biol 2023; 435:167956. [PMID: 36642157 PMCID: PMC10338645 DOI: 10.1016/j.jmb.2023.167956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/15/2022] [Accepted: 01/07/2023] [Indexed: 01/15/2023]
Abstract
The exon-junction complex (EJC) plays a role in post-transcriptional gene regulation and exerts antiviral activity towards several positive-strand RNA viruses. However, the spectrum of RNA viruses that are targeted by the EJC or the underlying mechanisms are not well understood. EJC components from Arabidopsis thaliana were screened for antiviral activity towards Turnip crinkle virus (TCV, Tombusviridae). Overexpression of the accessory EJC component CASC3 inhibited TCV accumulation > 10-fold in Nicotiana benthamiana while knock-down of endogenous CASC3 resulted in a > 4-fold increase in TCV accumulation. CASC3 forms cytoplasmic condensates and deletion of the conserved SELOR domain reduced condensate size 7-fold and significantly decreased antiviral activity towards TCV. Mass spectrometry of CASC3 complexes did not identify endogenous stress granule or P-body markers and CASC3 failed to co-localize with an aggresome-specific dye suggesting that CASC3 condensates are distinct from well-established membraneless compartments. Mass spectrometry and bimolecular fluorescence complementation assays revealed that CASC3 sequesters Heat shock protein 70 (Hsp70-1) and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), two host factors with roles in tombusvirus replication. Overexpression of Hsp70-1 or GAPDH reduced the antiviral activity of CASC3 2.1-fold and 2.8-fold, respectively, and suggests that CASC3 inhibits TCV by limiting host factor availability. Unrelated Tobacco mosaic virus (TMV) also depends on Hsp70-1 and CASC3 overexpression restricted TMV accumulation 4-fold and demonstrates that CASC3 antiviral activity is not TCV-specific. Like CASC3, Auxin response factor 19 (ARF19) forms poorly dynamic condensates but ARF19 overexpression failed to inhibit TCV accumulation and suggests that CASC3 has antiviral activities that are not ubiquitous among cytoplasmic condensates.
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Affiliation(s)
- Dana J Rademacher
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA
| | - Abudu I Bello
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA
| | - Jared P May
- Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, 5009 Rockhill Road, Kansas City, MO 64110, USA.
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3
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CPEB3 low-complexity motif regulates local protein synthesis via protein-protein interactions in neuronal ribonucleoprotein granules. Proc Natl Acad Sci U S A 2023; 120:e2114747120. [PMID: 36716374 PMCID: PMC9964033 DOI: 10.1073/pnas.2114747120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Biomolecular condensates, membraneless organelles found throughout the cell, play critical roles in many aspects of cellular function. Ribonucleoprotein granules (RNPs) are a type of biomolecular condensate necessary for local protein synthesis and are involved in synaptic plasticity and long-term memory. Most of the proteins in RNPs possess low-complexity motifs (LCM), allowing for increased promiscuity of protein-protein interactions. Here, we describe the importance of protein-protein interactions mediated by the LCM of RNA-binding protein cytoplasmic polyadenylation element binding protein 3 (CPEB3). CPEB3 is necessary for long-term synaptic plasticity and memory persistence, but the mechanisms involved are still not completely elucidated. We now present key mechanisms involved in its regulation of synaptic plasticity. We find that CPEB3-LCM plays a role in appropriate local protein synthesis of messenger ribonucleic acid (mRNA) targets, through crucial protein-protein interactions that drive localization to neuronal Decapping protein 1 (DCP1)-bodies. Translation-promoting CPEB3 and translation-inhibiting CPEB1 are packaged into neuronal RNP granules immediately after chemical long-term potentiation is induced, but only translation-promoting CPEB3 is repackaged to these organelles at later time points. This localization to neuronal RNP granules is critical for functional influence on translation as well as overall local protein synthesis (measured as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) insertion into the membrane and localization to the synapse). We therefore conclude that protein-protein interaction between the LCM of CPEB3 plays a critical role in local protein synthesis by utilizing neuronal RNP granules.
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4
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Emerging Roles of RNA-Binding Proteins in Neurodevelopment. J Dev Biol 2022; 10:jdb10020023. [PMID: 35735914 PMCID: PMC9224834 DOI: 10.3390/jdb10020023] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/02/2022] [Accepted: 06/08/2022] [Indexed: 02/06/2023] Open
Abstract
Diverse cell types in the central nervous system (CNS) are generated by a relatively small pool of neural stem cells during early development. Spatial and temporal regulation of stem cell behavior relies on precise coordination of gene expression. Well-studied mechanisms include hormone signaling, transcription factor activity, and chromatin remodeling processes. Much less is known about downstream RNA-dependent mechanisms including posttranscriptional regulation, nuclear export, alternative splicing, and transcript stability. These important functions are carried out by RNA-binding proteins (RBPs). Recent work has begun to explore how RBPs contribute to stem cell function and homeostasis, including their role in metabolism, transport, epigenetic regulation, and turnover of target transcripts. Additional layers of complexity are provided by the different target recognition mechanisms of each RBP as well as the posttranslational modifications of the RBPs themselves that alter function. Altogether, these functions allow RBPs to influence various aspects of RNA metabolism to regulate numerous cellular processes. Here we compile advances in RNA biology that have added to our still limited understanding of the role of RBPs in neurodevelopment.
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5
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Ho CH, Paolantoni C, Bawankar P, Tang Z, Brown S, Roignant J, Treisman JE. An exon junction complex-independent function of Barentsz in neuromuscular synapse growth. EMBO Rep 2022; 23:e53231. [PMID: 34726300 PMCID: PMC8728599 DOI: 10.15252/embr.202153231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 01/07/2023] Open
Abstract
The exon junction complex controls the translation, degradation, and localization of spliced mRNAs, and three of its core subunits also play a role in splicing. Here, we show that a fourth subunit, Barentsz, has distinct functions within and separate from the exon junction complex in Drosophila neuromuscular development. The distribution of mitochondria in larval muscles requires Barentsz as well as other exon junction complex subunits and is not rescued by a Barentsz transgene in which residues required for binding to the core subunit eIF4AIII are mutated. In contrast, interactions with the exon junction complex are not required for Barentsz to promote the growth of neuromuscular synapses. We find that the Activin ligand Dawdle shows reduced expression in barentsz mutants and acts downstream of Barentsz to control synapse growth. Both barentsz and dawdle are required in motor neurons, muscles, and glia for normal synapse growth, and exogenous Dawdle can rescue synapse growth in the absence of barentsz. These results identify a biological function for Barentsz that is independent of the exon junction complex.
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Affiliation(s)
- Cheuk Hei Ho
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
| | - Chiara Paolantoni
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
| | - Praveen Bawankar
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Zuojian Tang
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
Computational Biology at Ridgefield US, Global Computational Biology and Digital ScienceBoehringer IngelheimRidgefieldCTUSA
| | - Stuart Brown
- Center for Health Informatics and BioinformaticsNYU Langone Medical CenterNew YorkNYUSA
- Present address:
ExxonMobil Corporate Strategic ResearchAnnandaleNJUSA
| | - Jean‐Yves Roignant
- Center for Integrative Genomics, Génopode Building, Faculty of Biology and MedicineUniversity of LausanneLausanneSwitzerland
- Institute of Pharmaceutical and Biomedical SciencesJohannes Gutenberg‐University MainzMainzGermany
| | - Jessica E Treisman
- Skirball Institute for Biomolecular Medicine and Department of Cell BiologyNYU School of MedicineNew YorkNYUSA
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6
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Schieweck R, Schöneweiss EC, Harner M, Rieger D, Illig C, Saccà B, Popper B, Kiebler MA. Pumilio2 Promotes Growth of Mature Neurons. Int J Mol Sci 2021; 22:ijms22168998. [PMID: 34445704 PMCID: PMC8396670 DOI: 10.3390/ijms22168998] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 01/05/2023] Open
Abstract
RNA-binding proteins (RBPs) are essential regulators controlling both the cellular transcriptome and translatome. These processes enable cellular plasticity, an important prerequisite for growth. Cellular growth is a complex, tightly controlled process. Using cancer cells as model, we looked for RBPs displaying strong expression in published transcriptome datasets. Interestingly, we found the Pumilio (Pum) protein family to be highly expressed in all these cells. Moreover, we observed that Pum2 is regulated by basic fibroblast growth factor (bFGF). bFGF selectively enhances protein levels of Pum2 and the eukaryotic initiation factor 4E (eIF4E). Exploiting atomic force microscopy and in vitro pulldown assays, we show that Pum2 selects for eIF4E mRNA binding. Loss of Pum2 reduces eIF4E translation. Accordingly, depletion of Pum2 led to decreased soma size and dendritic branching of mature neurons, which was accompanied by a reduction in essential growth factors. In conclusion, we identify Pum2 as an important growth factor for mature neurons. Consequently, it is tempting to speculate that Pum2 may promote cancer growth.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
| | - Elisa-Charlott Schöneweiss
- Zentrum für Medizinische Biotechnologie (ZMB), University of Duisburg-Essen, 41541 Duisburg, Germany; (E.-C.S.); (B.S.)
| | - Max Harner
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
| | - Daniela Rieger
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
| | - Christin Illig
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
| | - Barbara Saccà
- Zentrum für Medizinische Biotechnologie (ZMB), University of Duisburg-Essen, 41541 Duisburg, Germany; (E.-C.S.); (B.S.)
| | - Bastian Popper
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
- Biomedical Center (BMC), Core Facility Animal Models, Ludwig-Maximilians-University, 82152 München, Germany
- Correspondence: ; Tel.: +49-89-2180-71996
| | - Michael A. Kiebler
- Biomedical Center (BMC), Department for Cell Biology & Anatomy, Medical Faculty, Ludwig-Maximilians-University, 82152 München, Germany; (R.S.); (M.H.); (D.R.); (C.I.); (M.A.K.)
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7
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Schieweck R, Ninkovic J, Kiebler MA. RNA-binding proteins balance brain function in health and disease. Physiol Rev 2020; 101:1309-1370. [PMID: 33000986 DOI: 10.1152/physrev.00047.2019] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Posttranscriptional gene expression including splicing, RNA transport, translation, and RNA decay provides an important regulatory layer in many if not all molecular pathways. Research in the last decades has positioned RNA-binding proteins (RBPs) right in the center of posttranscriptional gene regulation. Here, we propose interdependent networks of RBPs to regulate complex pathways within the central nervous system (CNS). These are involved in multiple aspects of neuronal development and functioning, including higher cognition. Therefore, it is not sufficient to unravel the individual contribution of a single RBP and its consequences but rather to study and understand the tight interplay between different RBPs. In this review, we summarize recent findings in the field of RBP biology and discuss the complex interplay between different RBPs. Second, we emphasize the underlying dynamics within an RBP network and how this might regulate key processes such as neurogenesis, synaptic transmission, and synaptic plasticity. Importantly, we envision that dysfunction of specific RBPs could lead to perturbation within the RBP network. This would have direct and indirect (compensatory) effects in mRNA binding and translational control leading to global changes in cellular expression programs in general and in synaptic plasticity in particular. Therefore, we focus on RBP dysfunction and how this might cause neuropsychiatric and neurodegenerative disorders. Based on recent findings, we propose that alterations in the entire regulatory RBP network might account for phenotypic dysfunctions observed in complex diseases including neurodegeneration, epilepsy, and autism spectrum disorders.
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Affiliation(s)
- Rico Schieweck
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Jovica Ninkovic
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Michael A Kiebler
- Biomedical Center (BMC), Department for Cell Biology and Anatomy, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
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8
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Sendino M, Omaetxebarria MJ, Prieto G, Rodriguez JA. Using a Simple Cellular Assay to Map NES Motifs in Cancer-Related Proteins, Gain Insight into CRM1-Mediated NES Export, and Search for NES-Harboring Micropeptides. Int J Mol Sci 2020; 21:E6341. [PMID: 32882917 PMCID: PMC7503480 DOI: 10.3390/ijms21176341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 12/26/2022] Open
Abstract
The nuclear export receptor CRM1 (XPO1) recognizes and binds specific sequence motifs termed nuclear export signals (NESs) in cargo proteins. About 200 NES motifs have been identified, but over a thousand human proteins are potential CRM1 cargos, and most of their NESs remain to be identified. On the other hand, the interaction of NES peptides with the "NES-binding groove" of CRM1 was studied in detail using structural and biochemical analyses, but a better understanding of CRM1 function requires further investigation of how the results from these in vitro studies translate into actual NES export in a cellular context. Here we show that a simple cellular assay, based on a recently described reporter (SRVB/A), can be applied to identify novel potential NESs motifs, and to obtain relevant information on different aspects of CRM1-mediated NES export. Using cellular assays, we first map 19 new sequence motifs with nuclear export activity in 14 cancer-related proteins that are potential CRM1 cargos. Next, we investigate the effect of mutations in individual NES-binding groove residues, providing further insight into CRM1-mediated NES export. Finally, we extend the search for CRM1-dependent NESs to a recently uncovered, but potentially vast, set of small proteins called micropeptides. By doing so, we report the first NES-harboring human micropeptides.
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Affiliation(s)
- Maria Sendino
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
| | - Miren Josu Omaetxebarria
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
| | - Gorka Prieto
- Department of Communications Engineering, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain;
| | - Jose Antonio Rodriguez
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
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9
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Kulkarni A, Lopez DH, Extavour CG. Shared Cell Biological Functions May Underlie Pleiotropy of Molecular Interactions in the Germ Lines and Nervous Systems of Animals. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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10
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Formicola N, Vijayakumar J, Besse F. Neuronal ribonucleoprotein granules: Dynamic sensors of localized signals. Traffic 2019; 20:639-649. [PMID: 31206920 DOI: 10.1111/tra.12672] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/03/2019] [Accepted: 06/11/2019] [Indexed: 12/14/2022]
Abstract
Membrane-less organelles, because of their capacity to dynamically, selectively and reversibly concentrate molecules, are very well adapted for local information processing and rapid response to environmental fluctuations. These features are particularly important in the context of neuronal cells, where synapse-specific activation, or localized extracellular cues, induce signaling events restricted to specialized axonal or dendritic subcompartments. Neuronal ribonucleoprotein (RNP) particles, or granules, are nonmembrane bound macromolecular condensates that concentrate specific sets of mRNAs and regulatory proteins, promoting their long-distance transport to axons or dendrites. Neuronal RNP granules also have a dual function in regulating the translation of associated mRNAs: while preventing mRNA translation at rest, they fuel local protein synthesis upon activation. As revealed by recent work, rapid and reversible switches between these two functional modes are triggered by modifications of the networks of interactions underlying RNP granule assembly. Such flexible properties also come with a cost, as neuronal RNP granules are prone to transition into pathological aggregates in response to mutations, aging, or cellular stresses, further emphasizing the need to better understand the mechanistic principles governing their dynamic assembly and regulation in living systems.
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11
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Mabin JW, Woodward LA, Patton RD, Yi Z, Jia M, Wysocki VH, Bundschuh R, Singh G. The Exon Junction Complex Undergoes a Compositional Switch that Alters mRNP Structure and Nonsense-Mediated mRNA Decay Activity. Cell Rep 2018; 25:2431-2446.e7. [PMID: 30466796 DOI: 10.1016/j.celrep.2018.11.046] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/22/2018] [Accepted: 11/12/2018] [Indexed: 01/08/2023] Open
Abstract
The exon junction complex (EJC) deposited upstream of mRNA exon junctions shapes structure, composition, and fate of spliced mRNA ribonucleoprotein particles (mRNPs). To achieve this, the EJC core nucleates assembly of a dynamic shell of peripheral proteins that function in diverse post-transcriptional processes. To illuminate consequences of EJC composition change, we purified EJCs from human cells via peripheral proteins RNPS1 and CASC3. We show that the EJC originates as an SR-rich mega-dalton-sized RNP that contains RNPS1 but lacks CASC3. Sometime before or during translation, the EJC undergoes compositional and structural remodeling into an SR-devoid monomeric complex that contains CASC3. Surprisingly, RNPS1 is important for nonsense-mediated mRNA decay (NMD) in general, whereas CASC3 is needed for NMD of only select mRNAs. The switch to CASC3-EJC slows down NMD. Overall, the EJC compositional switch dramatically alters mRNP structure and specifies two distinct phases of EJC-dependent NMD.
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Affiliation(s)
- Justin W Mabin
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Lauren A Woodward
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Robert D Patton
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Zhongxia Yi
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Mengxuan Jia
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Bundschuh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Department of Physics, The Ohio State University, Columbus, OH 43210, USA; Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Guramrit Singh
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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12
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Lu W, Lakonishok M, Serpinskaya AS, Kirchenbüechler D, Ling SC, Gelfand VI. Ooplasmic flow cooperates with transport and anchorage in Drosophila oocyte posterior determination. J Cell Biol 2018; 217:3497-3511. [PMID: 30037924 PMCID: PMC6168253 DOI: 10.1083/jcb.201709174] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/27/2018] [Accepted: 07/03/2018] [Indexed: 12/21/2022] Open
Abstract
Conventional kinesin is essential for Drosophila melanogaster posterior determination by localizing oskar mRNA at the oocyte posterior pole. In this study, we show that two essential kinesin functions, cargo transport and cytoplasmic streaming, together with a myosin V–mediated cortical anchorage ensure correct posterior determination. The posterior determination of the Drosophila melanogaster embryo is defined by the posterior localization of oskar (osk) mRNA in the oocyte. Defects of its localization result in a lack of germ cells and failure of abdomen specification. A microtubule motor kinesin-1 is essential for osk mRNA posterior localization. Because kinesin-1 is required for two essential functions in the oocyte—transport along microtubules and cytoplasmic streaming—it is unclear how individual kinesin-1 activities contribute to the posterior determination. We examined Staufen, an RNA-binding protein that is colocalized with osk mRNA, as a proxy of posterior determination, and we used mutants that either inhibit kinesin-driven transport along microtubules or cytoplasmic streaming. We demonstrated that late-stage streaming is partially redundant with early-stage transport along microtubules for Staufen posterior localization. Additionally, an actin motor, myosin V, is required for the Staufen anchoring to the actin cortex. We propose a model whereby initial kinesin-driven transport, subsequent kinesin-driven streaming, and myosin V–based cortical retention cooperate in posterior determination.
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Affiliation(s)
- Wen Lu
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Margot Lakonishok
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Anna S Serpinskaya
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - David Kirchenbüechler
- Center for Advanced Microscopy and the Nikon Imaging Center, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Shuo-Chien Ling
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Program in Neuroscience and Behavior Disorders, Duke-National University of Singapore Medical School, Singapore
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL
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13
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Kim JY, Deglincerti A, Jaffrey SR. A Staufen1-mediated decay pathway influences the local transcriptome in axons. ACTA ACUST UNITED AC 2017; 5:e1414016. [PMID: 29416957 DOI: 10.1080/21690731.2017.1414016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 11/28/2017] [Indexed: 12/23/2022]
Abstract
Local translation is critical for diverse aspects of neuronal function, including mediating responses of elongating axons to guidance cues and other signaling molecules. A major determinant of the protein synthetic capacity of axons and growth cones is the specific set of mRNAs that are trafficked to these sites. However, recently it has become clear that the axonal transcriptome can also be shaped by local RNA degradation mechanisms, such as nonsense-mediated decay. Here we show that Staufen1-mediated decay can also occur within axons and mediate degradation of specific axonal transcripts. We show that Staufen1 and Upf1, which function together in Staufen1-mediated decay, are localized in growth cones. Selective depletion of Staufen1 from neurons results in a complex pattern of transcriptional alterations, with a subset of transcripts showing increased expression and increased RNA half-life consistent with their regulation by Staufen1-mediated decay. Additionally, we show certain transcripts, such as Rac1, are regulated by Staufen1 within axons and growth cones. The functional significance of Staufen1 in growth cones is supported by morphological alterations in growth cones following Staufen1 knockdown. Together these data point to Staufen1-mediated decay as a novel mechanism to control mRNA expression levels in axons and growth cones through local RNA degradation.
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Affiliation(s)
- Ju Youn Kim
- Department of Pharmacology, Weill-Cornell Medical College, Cornell University, New York, NY, USA
| | - Alessia Deglincerti
- Department of Pharmacology, Weill-Cornell Medical College, Cornell University, New York, NY, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill-Cornell Medical College, Cornell University, New York, NY, USA
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Rossi A, Moro A, Tebaldi T, Cornella N, Gasperini L, Lunelli L, Quattrone A, Viero G, Macchi P. Identification and dynamic changes of RNAs isolated from RALY-containing ribonucleoprotein complexes. Nucleic Acids Res 2017; 45:6775-6792. [PMID: 28379492 PMCID: PMC5499869 DOI: 10.1093/nar/gkx235] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/30/2017] [Indexed: 12/13/2022] Open
Abstract
RALY is a member of the heterogeneous nuclear ribonucleoprotein family (hnRNP), a large family of RNA-binding proteins involved in many aspects of RNA metabolism. Although RALY interactome has been recently characterized, a comprehensive global analysis of RALY-associated RNAs is lacking and the biological function of RALY remains elusive. Here, we performed RIP-seq analysis to identify RALY interacting RNAs and assessed the role of RALY in gene expression. We demonstrate that RALY binds specific coding and non-coding RNAs and associates with translating mRNAs of mammalian cells. Among the identified transcripts, we focused on ANXA1 and H1FX mRNAs, encoding for Annexin A1 and for the linker variant of the histone H1X, respectively. Both proteins are differentially expressed by proliferating cells and are considered as markers for tumorigenesis. We demonstrate that cells lacking RALY expression exhibit changes in the levels of H1FX and ANXA1 mRNAs and proteins in an opposite manner. We also provide evidence for a direct binding of RALY to the U-rich elements present within the 3΄UTR of both transcripts. Thus, our results identify RALY as a poly-U binding protein and as a regulator of H1FX and ANXA1 in mammalian cells.
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Affiliation(s)
- Annalisa Rossi
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Albertomaria Moro
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Toma Tebaldi
- Laboratory of Translational Genomics, CIBIO - Centre for Integrative Biology, University of Trento, Italy
| | - Nicola Cornella
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Lisa Gasperini
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
| | - Lorenzo Lunelli
- Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (TN), Italy
| | - Alessandro Quattrone
- Laboratory of Translational Genomics, CIBIO - Centre for Integrative Biology, University of Trento, Italy
| | - Gabriella Viero
- Institute of Biophysics, CNR-Italian National Council for Research, via Sommarive 18, 38123 Trento (TN), Italy
| | - Paolo Macchi
- Laboratory of Molecular and Cellular Neurobiology, Centre for Integrative Biology, University of Trento, via Sommarive 9, 38123 Trento (TN), Italy
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15
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Schieweck R, Popper B, Kiebler MA. Co-Translational Folding: A Novel Modulator of Local Protein Expression in Mammalian Neurons? Trends Genet 2016; 32:788-800. [DOI: 10.1016/j.tig.2016.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 01/15/2023]
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16
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Choudhury SR, Singh AK, McLeod T, Blanchette M, Jang B, Badenhorst P, Kanhere A, Brogna S. Exon junction complex proteins bind nascent transcripts independently of pre-mRNA splicing in Drosophila melanogaster. eLife 2016; 5. [PMID: 27879206 PMCID: PMC5158136 DOI: 10.7554/elife.19881] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 11/21/2016] [Indexed: 12/16/2022] Open
Abstract
Although it is currently understood that the exon junction complex (EJC) is recruited on spliced mRNA by a specific interaction between its central protein, eIF4AIII, and splicing factor CWC22, we found that eIF4AIII and the other EJC core proteins Y14 and MAGO bind the nascent transcripts of not only intron-containing but also intronless genes on Drosophila polytene chromosomes. Additionally, Y14 ChIP-seq demonstrates that association with transcribed genes is also splicing-independent in Drosophila S2 cells. The association of the EJC proteins with nascent transcripts does not require CWC22 and that of Y14 and MAGO is independent of eIF4AIII. We also show that eIF4AIII associates with both polysomal and monosomal RNA in S2 cell extracts, whereas Y14 and MAGO fractionate separately. Cumulatively, our data indicate a global role of eIF4AIII in gene expression, which would be independent of Y14 and MAGO, splicing, and of the EJC, as currently understood. DOI:http://dx.doi.org/10.7554/eLife.19881.001 Cells and organisms survive and thrive in large part due to the activities of thousands of proteins. The instructions for making these proteins are found in the DNA sequences of genes. However, these genes also tend to contain large sections called introns that do not encode protein. To make a protein, the gene’s full sequence is first copied to a temporary molecule called pre-messenger RNA (pre-mRNA for short). The introns are then removed from the pre-mRNA in a process known as splicing in the cell nucleus, during which the remaining regions of the molecule, called exons, are joined together to form a mature mRNA molecule. This mature mRNA can then move out of the cell nucleus and be used as a template to build proteins around the cell. Intriguingly, splicing of the pre-mRNAs in the nucleus affects how the mRNA is used to make proteins in the cytoplasm of the cell. This nucleus-cytoplasm connection is currently explained by the so-called exon junction complex, which is thought to attach to mature mRNAs at the junction between two exons and stay bound until the mRNA moves to the cytoplasm. Evidence suggests the exon junction complex affects how the mRNA is used to make protein, yet little is known about how it would do so. Choudhury, Singh et al. examined how exon junction complex proteins bind to newly made RNA in salivary gland cells of fruit flies and in cultured cells. Contrary to expectations, the three proteins thought to make the central part of the exon junction complex were found on different mRNAs and regardless of whether the mRNAs derived from genes with introns. Specifically, one of these proteins – eIF4AIII – can remain on the mRNA independently of the two other exon junction complex proteins or CWC22, a protein required for splicing. CWC22 is also thought to be required for the complex to be deposited precisely at exon junctions in human cells. Overall, it appears that our current understanding of the exon junction complex needs to be revised. The findings presented by Choudhury, Singh et al. predict alternative roles for these proteins, particularly eIF4AIII, which will be independent of any deposition of the exon junction complex. DOI:http://dx.doi.org/10.7554/eLife.19881.002
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Affiliation(s)
| | - Anand K Singh
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Tina McLeod
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Marco Blanchette
- Stowers Institute for Medical Research, Kansas city, United States
| | - Boyun Jang
- Institute of Biomedical Research, University of Birmingham, Birmingham, United Kingdom
| | - Paul Badenhorst
- Institute of Biomedical Research, University of Birmingham, Birmingham, United Kingdom
| | - Aditi Kanhere
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Saverio Brogna
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
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17
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Abstract
Germ granules are the hallmark of all germ cells. These membrane-less, electron-dense structures were first observed over 100 years ago. Today, their role in regulating and processing transcripts critical for the establishment, maintenance, and protection of germ cells is well established, and pathways outlining the biochemical mechanisms and physical properties associated with their biogenesis are emerging.
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Affiliation(s)
- Ruth Lehmann
- Howard Hughes Medical Institute (HHMI), Department of Cell Biology, Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, USA.
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18
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Fernandez-Moya SM, Bauer KE, Kiebler MA. Meet the players: local translation at the synapse. Front Mol Neurosci 2014; 7:84. [PMID: 25426019 PMCID: PMC4227489 DOI: 10.3389/fnmol.2014.00084] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/15/2014] [Indexed: 01/10/2023] Open
Abstract
It is widely believed that activity-dependent synaptic plasticity is the basis for learning and memory. Both processes are dependent on new protein synthesis at the synapse. Here, we describe a mechanism how dendritic mRNAs are transported and subsequently translated at activated synapses. Furthermore, we present the players involved in the regulation of local dendritic translation upon neuronal stimulation and their molecular interplay that maintain local proteome homeostasis. Any dysregulation causes several types of neurological disorders including muscular atrophies, cancers, neuropathies, neurodegenerative, and cognitive disorders.
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Affiliation(s)
| | - Karl E Bauer
- Department of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Germany
| | - Michael A Kiebler
- Department of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Germany
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19
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Cougot N, Daguenet E, Baguet A, Cavalier A, Thomas D, Bellaud P, Fautrel A, Godey F, Bertrand E, Tomasetto C, Gillet R. Overexpression of MLN51 triggers P-body disassembly and formation of a new type of RNA granules. J Cell Sci 2014; 127:4692-701. [PMID: 25205763 DOI: 10.1242/jcs.154500] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Metastatic lymph node 51 (MLN51, also known as CASC3) is a core component of the exon junction complex (EJC), which is loaded onto spliced mRNAs and plays an essential role in determining their fate. Unlike the three other EJC core components [eIF4AIII, Magoh and Y14 (also known as RBM8A)], MLN51 is mainly located in the cytoplasm, where it plays a key role in the assembly of stress granules. In this study, we further investigated the cytoplasmic role of MLN51. We show that MLN51 is a new component of processing bodies (P-bodies). When overexpressed, MLN51 localizes in novel small cytoplasmic foci. These contain RNA, show directed movements and are distinct from stress granules and P-bodies. The appearance of these foci correlates with the process of P-body disassembly. A similar reduction in P-body count is also observed in human HER2-positive (HER2(+)) breast cancer cells overexpressing MLN51. This suggests that P-body disassembly and subsequent mRNA deregulation might correlate with cancer progression.
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Affiliation(s)
- Nicolas Cougot
- Université de Rennes 1, UMR CNRS 6290 IGDR, «Translation and Folding Team», Campus de Beaulieu, 35042 Rennes cedex, France
| | - Elisabeth Daguenet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/U964 INSERM/Université de Strasbourg, 67404 Illkirch, France
| | - Aurélie Baguet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/U964 INSERM/Université de Strasbourg, 67404 Illkirch, France
| | - Annie Cavalier
- Université de Rennes 1, UMR CNRS 6290 IGDR, «Translation and Folding Team», Campus de Beaulieu, 35042 Rennes cedex, France
| | - Daniel Thomas
- Université de Rennes 1, UMR CNRS 6290 IGDR, «Translation and Folding Team», Campus de Beaulieu, 35042 Rennes cedex, France
| | - Pascale Bellaud
- Unité INSERM 991, Plateforme histopathologique, IFR 140 GFAS, Université de Rennes 1, 35043 Rennes, France
| | - Alain Fautrel
- Unité INSERM 991, Plateforme histopathologique, IFR 140 GFAS, Université de Rennes 1, 35043 Rennes, France
| | - Florence Godey
- Centre de Ressources Biologiques Santé de Rennes, Centre Eugène Marquis, Rue de la Bataille Flandres Dunkerque - 35042 Rennes cedex, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, CNRS, UMR 5535, 34293 Montpellier cedex 5, France
| | - Catherine Tomasetto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/U964 INSERM/Université de Strasbourg, 67404 Illkirch, France
| | - Reynald Gillet
- Université de Rennes 1, UMR CNRS 6290 IGDR, «Translation and Folding Team», Campus de Beaulieu, 35042 Rennes cedex, France
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20
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The functions and regulatory principles of mRNA intracellular trafficking. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 825:57-96. [PMID: 25201103 DOI: 10.1007/978-1-4939-1221-6_2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The subcellular localization of RNA molecules is a key step in the control of gene expression that impacts a broad array of biological processes in different organisms and cell types. Like other aspects of posttranscriptional gene regulation discussed in this collection of reviews, the intracellular trafficking of mRNAs is modulated by a complex regulatory code implicating specific cis-regulatory elements, RNA-binding proteins, and cofactors that function combinatorially to dictate precise localization mechanisms. In this review, we first discuss the functional benefits of transcript localization, the regulatory principles involved, and specific molecular mechanisms that have been described for a few well-characterized mRNAs. We also overview some of the emerging genomic and imaging technologies that have provided significant insights into this layer of gene regulation. Finally, we highlight examples of human diseases where defective transcript localization has been documented.
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21
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Fritzsche R, Karra D, Bennett KL, Ang FY, Heraud-Farlow JE, Tolino M, Doyle M, Bauer KE, Thomas S, Planyavsky M, Arn E, Bakosova A, Jungwirth K, Hörmann A, Palfi Z, Sandholzer J, Schwarz M, Macchi P, Colinge J, Superti-Furga G, Kiebler MA. Interactome of two diverse RNA granules links mRNA localization to translational repression in neurons. Cell Rep 2013; 5:1749-62. [PMID: 24360960 DOI: 10.1016/j.celrep.2013.11.023] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 10/07/2013] [Accepted: 11/12/2013] [Indexed: 01/07/2023] Open
Abstract
Transport of RNAs to dendrites occurs in neuronal RNA granules, which allows local synthesis of specific proteins at active synapses on demand, thereby contributing to learning and memory. To gain insight into the machinery controlling dendritic mRNA localization and translation, we established a stringent protocol to biochemically purify RNA granules from rat brain. Here, we identified a specific set of interactors for two RNA-binding proteins that are known components of neuronal RNA granules, Barentsz and Staufen2. First, neuronal RNA granules are much more heterogeneous than previously anticipated, sharing only a third of the identified proteins. Second, dendritically localized mRNAs, e.g., Arc and CaMKIIα, associate selectively with distinct RNA granules. Third, our work identifies a series of factors with known roles in RNA localization, translational control, and RNA quality control that are likely to keep localized transcripts in a translationally repressed state, often in distinct types of RNPs.
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Affiliation(s)
- Renate Fritzsche
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Daniela Karra
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Foong Yee Ang
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Department for Anatomy & Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Jacki E Heraud-Farlow
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Marco Tolino
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Michael Doyle
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Karl E Bauer
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Department for Anatomy & Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Sabine Thomas
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany; Department for Anatomy & Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Melanie Planyavsky
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Eric Arn
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Anetta Bakosova
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Kerstin Jungwirth
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Alexandra Hörmann
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Zsofia Palfi
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Julia Sandholzer
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Martina Schwarz
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Paolo Macchi
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Jacques Colinge
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Michael A Kiebler
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria; Max-Planck-Institute for Developmental Biology, 72076 Tübingen, Germany; Department for Anatomy & Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany.
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22
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Heraud-Farlow JE, Sharangdhar T, Li X, Pfeifer P, Tauber S, Orozco D, Hörmann A, Thomas S, Bakosova A, Farlow AR, Edbauer D, Lipshitz HD, Morris QD, Bilban M, Doyle M, Kiebler MA. Staufen2 regulates neuronal target RNAs. Cell Rep 2013; 5:1511-8. [PMID: 24360961 DOI: 10.1016/j.celrep.2013.11.039] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 11/04/2013] [Accepted: 11/21/2013] [Indexed: 11/30/2022] Open
Abstract
RNA-binding proteins play crucial roles in directing RNA translation to neuronal synapses. Staufen2 (Stau2) has been implicated in both dendritic RNA localization and synaptic plasticity in mammalian neurons. Here, we report the identification of functionally relevant Stau2 target mRNAs in neurons. The majority of Stau2-copurifying mRNAs expressed in the hippocampus are present in neuronal processes, further implicating Stau2 in dendritic mRNA regulation. Stau2 targets are enriched for secondary structures similar to those identified in the 3' UTRs of Drosophila Staufen targets. Next, we show that Stau2 regulates steady-state levels of many neuronal RNAs and that its targets are predominantly downregulated in Stau2-deficient neurons. Detailed analysis confirms that Stau2 stabilizes the expression of one synaptic signaling component, the regulator of G protein signaling 4 (Rgs4) mRNA, via its 3' UTR. This study defines the global impact of Stau2 on mRNAs in neurons, revealing a role in stabilization of the levels of synaptic targets.
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Affiliation(s)
- Jacki E Heraud-Farlow
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria; Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Tejaswini Sharangdhar
- Department of Anatomy and Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Xiao Li
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; The Donnelly Centre, University of Toronto, Toronto, ON M5S 1E3, Canada
| | - Philipp Pfeifer
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria
| | - Stefanie Tauber
- Department of Laboratory Medicine and Core Facility Genomics, Medical University of Vienna, 1090 Vienna, Austria
| | - Denise Orozco
- Adolf Butenandt Institute, Ludwig-Maximilians-University, 80336 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 80336 Munich, Germany
| | - Alexandra Hörmann
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria
| | - Sabine Thomas
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria; Department of Anatomy and Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Anetta Bakosova
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria
| | - Ashley R Farlow
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Dieter Edbauer
- Adolf Butenandt Institute, Ludwig-Maximilians-University, 80336 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), 80336 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), 80336 Munich, Germany
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Quaid D Morris
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; The Donnelly Centre, University of Toronto, Toronto, ON M5S 1E3, Canada
| | - Martin Bilban
- Department of Laboratory Medicine and Core Facility Genomics, Medical University of Vienna, 1090 Vienna, Austria
| | - Michael Doyle
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria.
| | - Michael A Kiebler
- Department of Neuronal Cell Biology, Center for Brain Research, 1090 Vienna, Austria; Department of Anatomy and Cell Biology, Ludwig-Maximilians-University, 80336 Munich, Germany.
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23
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Tenzer S, Moro A, Kuharev J, Francis AC, Vidalino L, Provenzani A, Macchi P. Proteome-wide characterization of the RNA-binding protein RALY-interactome using the in vivo-biotinylation-pulldown-quant (iBioPQ) approach. J Proteome Res 2013; 12:2869-84. [PMID: 23614458 DOI: 10.1021/pr400193j] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RALY is a member of the heterogeneous nuclear ribonucleoproteins, a family of RNA-binding proteins generally involved in many processes of mRNA metabolism. No quantitative proteomic analysis of RALY-containing ribonucleoparticles (RNPs) has been performed so far, and the biological role of RALY remains elusive. Here, we present a workflow for the characterization of RALY's interaction partners, termed iBioPQ, that involves in vivo biotinylation of biotin acceptor peptide (BAP)-fused protein in the presence of the prokaryotic biotin holoenzyme synthetase of BirA so that it can be purified using streptavidin-coated magnetic beads, circumventing the need for specific antibodies and providing efficient pulldowns. Protein eluates were subjected to tryptic digestion and identified using data-independent acquisition on an ion-mobility enabled high-resolution nanoUPLC-QTOF system. Using label-free quantification, we identified 143 proteins displaying at least 2-fold difference in pulldown compared to controls. Gene Ontology overrepresentation analysis revealed an enrichment of proteins involved in mRNA metabolism and translational control. Among the most abundant interacting proteins, we confirmed RNA-dependent interactions of RALY with MATR3, PABP1 and ELAVL1. Comparative analysis of pulldowns after RNase treatment revealed a protein-protein interaction of RALY with eIF4AIII, FMRP, and hnRNP-C. Our data show that RALY-containing RNPs are much more heterogeneous than previously hypothesized.
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Affiliation(s)
- Stefan Tenzer
- Institute for Immunology, University Medical Center of the Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany
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24
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Leal G, Comprido D, Duarte CB. BDNF-induced local protein synthesis and synaptic plasticity. Neuropharmacology 2013; 76 Pt C:639-56. [PMID: 23602987 DOI: 10.1016/j.neuropharm.2013.04.005] [Citation(s) in RCA: 425] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/25/2013] [Accepted: 04/03/2013] [Indexed: 12/16/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptic transmission and long-term potentiation (LTP) in the hippocampus and in other brain regions, playing a role in the formation of certain forms of memory. The effects of BDNF in LTP are mediated by TrkB (tropomyosin-related kinase B) receptors, which are known to be coupled to the activation of the Ras/ERK, phosphatidylinositol 3-kinase/Akt and phospholipase C-γ (PLC-γ) pathways. The role of BDNF in LTP is best studied in the hippocampus, where the neurotrophin acts at pre- and post-synaptic levels. Recent studies have shown that BDNF regulates the transport of mRNAs along dendrites and their translation at the synapse, by modulating the initiation and elongation phases of protein synthesis, and by acting on specific miRNAs. Furthermore, the effect of BDNF on transcription regulation may further contribute to long-term changes in the synaptic proteome. In this review we discuss the recent progress in understanding the mechanisms contributing to the short- and long-term regulation of the synaptic proteome by BDNF, and the role in synaptic plasticity, which is likely to influence learning and memory formation. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
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Affiliation(s)
- Graciano Leal
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
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25
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Regulatory mechanism of G protein-coupled receptor trafficking to the plasma membrane: a role for mRNA localization. Methods Enzymol 2013. [PMID: 23351737 DOI: 10.1016/b978-0-12-391862-8.00007-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Trafficking and localization of G protein-coupled receptors (GPCRs) to the plasma membrane and its retention in the agonist-naive state are critically important for signaling by these receptors. Agonist-induced desensitization of activated GPCRs and their removal from the cell surface have been studied and reviewed extensively. However, less attention has been given to the regulatory mechanisms and different steps that control the trafficking of newly synthesized receptors to the plasma membrane. It is generally believed that the mRNAs encoding GPCRs are targeted to the endoplasmic reticulum by a cotranslational, signal-sequence recognition particle-dependent pathway that results in protein translation and translocation to the plasma membrane. In this chapter, we discuss the importance of cis-targeting elements and trans-recognition factors in GPCR mRNA translational silencing, trafficking, and localization within the cell and its importance in receptor trafficking to the plasma membrane. Knockdown of the critical trans-recognition factors (RNA-binding proteins) resulted in translation of GPCR mRNAs in the perinuclear region and the receptors failed to traffic to the plasma membrane. Thus, a new paradigm is emerging in GPCR trafficking that suggests a fundamental role for mRNA partitioning to specific cytoplasmic regions for efficient plasma membrane localization of the receptors.
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Daguenet E, Baguet A, Degot S, Schmidt U, Alpy F, Wendling C, Spiegelhalter C, Kessler P, Rio MC, Le Hir H, Bertrand E, Tomasetto C. Perispeckles are major assembly sites for the exon junction core complex. Mol Biol Cell 2012; 23:1765-82. [PMID: 22419818 PMCID: PMC3338441 DOI: 10.1091/mbc.e12-01-0040] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The exon junction complex (EJC) allows the spliceosome to communicate with other cellular machinery. This study shows that assembled EJC cores are enriched in nuclear regions around speckles, called perispeckles. Speckles and perispeckles may represent specialized nuclear regions for messenger ribonucleoprotein maturation. The exon junction complex (EJC) is loaded onto mRNAs as a consequence of splicing and regulates multiple posttranscriptional events. MLN51, Magoh, Y14, and eIF4A3 form a highly stable EJC core, but where this tetrameric complex is assembled in the cell remains unclear. Here we show that EJC factors are enriched in domains that we term perispeckles and are visible as doughnuts around nuclear speckles. Fluorescence resonance energy transfer analyses and EJC assembly mutants show that perispeckles do not store free subunits, but instead are enriched for assembled cores. At the ultrastructural level, perispeckles are distinct from interchromatin granule clusters that may function as storage sites for splicing factors and intermingle with perichromatin fibrils, where nascent RNAs and active RNA Pol II are present. These results support a model in which perispeckles are major assembly sites for the tetrameric EJC core. This subnuclear territory thus represents an intermediate region important for mRNA maturation, between transcription sites and splicing factor reservoirs and assembly sites.
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Affiliation(s)
- Elisabeth Daguenet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Unité Mixte de Recherche 7104, Centre National de la Recherche Scientifique/U964 Institut National de Santé et de Recherche Médicale/Université de Strasbourg, 67404 Illkirch, France
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Bilogan CK, Horb ME. Xenopus staufen2 is required for anterior endodermal organ formation. Genesis 2012; 50:251-9. [PMID: 22162130 DOI: 10.1002/dvg.22000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 01/30/2023]
Abstract
Defining the regulatory molecular networks involved in patterning the developing anterior endoderm is essential to understand how the pancreas, liver, stomach, and duodenum are discretely specified from each other. In this study, we analyzed the expression and function of the double-stranded RNA-binding protein Staufen2 in Xenopus laevis endoderm. We found that staufen2 was broadly expressed within the developing endoderm beginning at gastrulation becoming localized to the anterior endoderm at later stages. Through morpholino-mediated knockdown, we demonstrate that Staufen2 function is required for proper formation of the stomach, liver, and pancreas. We define that its function is required during gastrulation for proper patterning of the dorsal-ventral axis and that it acts to regulate expression of BMP signaling components.
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Affiliation(s)
- Cassandra K Bilogan
- Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, USA
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Abstract
Eukaryotic cells possess highly sophisticated membrane trafficking pathways that define specific membrane domains and provide a means for moving vesicles between them (Mostov, Su, and ter Beest, 2003, Nat. Cell Biol. 5, 287-293). Here, I review recent data that indicate a role for membrane trafficking in mRNA localization. Specifically, I review evidence that some localized mRNAs are anchored to specific membrane domains and/or transported on membranous organelles or vesicles to specific subcellular sites. This review is not intended as a discussion on indirect influences of membrane trafficking on mRNA localization. I will not, for example, discuss the role of membrane trafficking in the regulation of extracellular signalling events that could indirectly influence mRNA localization through polarization of the actin or microtubule cytoskeleton (for examples, see reviews by Drubin and Nelson, 1996, Cell 84, 335-344; Shulman and St Johnston, 1999, Trends Cell Biol. 9, M60-M64).
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Affiliation(s)
- Robert S Cohen
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Dr, Lawrence, KS 66045, USA.
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Miki T, Kamikawa Y, Kurono S, Kaneko Y, Katahira J, Yoneda Y. Cell type-dependent gene regulation by Staufen2 in conjunction with Upf1. BMC Mol Biol 2011; 12:48. [PMID: 22087843 PMCID: PMC3226675 DOI: 10.1186/1471-2199-12-48] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 11/16/2011] [Indexed: 12/01/2022] Open
Abstract
Background Staufen2 (Stau2), a double-stranded RNA-binding protein, is a component of neuronal RNA granules, which are dendritic mRNA transport machines. Although Stau2 is thought to be involved in the dendritic targeting of several mRNAs in neurons, the mechanism whereby Stau2 regulates these mRNAs is unknown. To elucidate the functions of Stau2, we screened for novel binding partners by affinity purification of GST-tagged Stau2 from 293F cells. Results Three RNA helicases, RNA helicase A, Upf1 and Mov10, were identified in Stau2-containing complexes. We focused our studies on Upf1, a key player in nonsense-mediated mRNA decay. Stau2 was found to bind directly to Upf1 in an RNA-independent manner in vitro. Tethering Stau2 to the 3'-untranslated region (UTR) of a reporter gene had little effect on its expression in HeLa cells. In contrast, when the same tethering assay was performed in 293F cells, we observed an increase in reporter protein levels. This upregulation of protein expression by Stau2 turned out to be dependent on Upf1. Moreover, we found that in 293F cells, Stau2 upregulates the reporter mRNA level in an Upf1-independent manner. Conclusions These results indicate that the recruitment of Stau2 alone or in combination with Upf1 differentially affects the fate of mRNAs. Moreover, the results suggest that Stau2-mediated fate determination could be executed in a cell type-specific manner.
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Affiliation(s)
- Takashi Miki
- Department of Frontier Bioscience, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka, Suita, Osaka, Japan
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Megakaryocytes differentially sort mRNAs for matrix metalloproteinases and their inhibitors into platelets: a mechanism for regulating synthetic events. Blood 2011; 118:1903-11. [PMID: 21628401 DOI: 10.1182/blood-2010-12-324517] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Megakaryocytes transfer a diverse and functional transcriptome to platelets during the final stages of thrombopoiesis. In platelets, these transcripts reflect the expression of their corresponding proteins and, in some cases, serve as a template for translation. It is not known, however, if megakaryocytes differentially sort mRNAs into platelets. Given their critical role in vascular remodeling and inflammation, we determined whether megakaryocytes selectively dispense transcripts for matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) into platelets. Next-generation sequencing (RNA-Seq) revealed that megakaryocytes express mRNA for 10 of the 24 human MMP family members. mRNA for all of these MMPs are present in platelets with the exception of MMP-2, 14, and 15. Megakaryocytes and platelets also express mRNA for TIMPs 1-3, but not TIMP-4. mRNA expression patterns predicted the presence and, in most cases, the abundance of each corresponding protein. Nonetheless, exceptions were observed: MMP-2 protein is present in platelets but not its transcript. In contrast, quiescent platelets express TIMP-2 mRNA but only traces of TIMP-2 protein. In response to activating signals, however, platelets synthesize significant amounts of TIMP-2 protein. These results demonstrate that megakaryocytes differentially express mRNAs for MMPs and TIMPs and selectively transfer a subset of these into platelets. Among the platelet messages, TIMP-2 serves as a template for signal-dependent translation.
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Bono F, Gehring NH. Assembly, disassembly and recycling: the dynamics of exon junction complexes. RNA Biol 2011; 8:24-9. [PMID: 21289489 DOI: 10.4161/rna.8.1.13618] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Efficient gene expression requires that, during their lifetime, mRNAs associate with different sets of RNA binding proteins to form messenger ribonucleoprotein particles (mRNPs). The protein components of mRNPs are essential for the correct post-transcriptional function and regulation of mRNAs. mRNPs are constitutively remodeled during the maturation of the mRNA in the nucleus and downstream steps in the cytoplasm, and can also change depending on the cellular environment. Here we review the current understanding of the biochemical and structural aspects of a central mRNP component and regulator, the exon junction complex (EJC).
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Affiliation(s)
- Fulvia Bono
- Max-Planck-Institute for Developmental Biology, Tübingen, Germany.
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32
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Ashton-Beaucage D, Udell CM, Lavoie H, Baril C, Lefrançois M, Chagnon P, Gendron P, Caron-Lizotte O, Bonneil É, Thibault P, Therrien M. The Exon Junction Complex Controls the Splicing of mapk and Other Long Intron-Containing Transcripts in Drosophila. Cell 2010; 143:251-62. [DOI: 10.1016/j.cell.2010.09.014] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 08/31/2010] [Accepted: 09/02/2010] [Indexed: 12/11/2022]
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Lee KM, Hsu IW, Tarn WY. TRAP150 activates pre-mRNA splicing and promotes nuclear mRNA degradation. Nucleic Acids Res 2010; 38:3340-50. [PMID: 20123736 PMCID: PMC2879504 DOI: 10.1093/nar/gkq017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
TRAP150 has been identified as a subunit of the transcription regulatory complex TRAP/Mediator, and also a component of the spliceosome. The exact function of TRAP150, however, remains unclear. We recently identified TRAP150 by its association with the mRNA export factor TAP. TRAP150 contains an arginine/serine-rich domain and has sequence similarity with the cell death-promoting transcriptional repressor BCLAF1. We found that TRAP150 co-localizes with splicing factors in nuclear speckles, and is required for pre-mRNA splicing and activates splicing in vivo. TRAP150 remains associated with the spliced mRNA after splicing, and accordingly, it interacts with the integral exon junction complex. Unexpectedly, when tethered to a precursor mRNA, TRAP150 can trigger mRNA degradation in the nucleus. However, unlike nonsense-mediated decay, TRAP150-mediated mRNA decay is irrespective of the presence of upstream stop codons and occurs in the nucleus. Moreover, TRAP150 activates pre-mRNA splicing and induces mRNA degradation by its separable functional domains. Therefore, TRAP150 represents a multi-functional protein involved in nuclear mRNA metabolism.
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Affiliation(s)
- Kuo-Ming Lee
- Institute of Biomedical Sciences, Academia Sinica, College of Medicine, National Taiwan University, Taipei, Taiwan
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Mammalian Pumilio 2 regulates dendrite morphogenesis and synaptic function. Proc Natl Acad Sci U S A 2010; 107:3222-7. [PMID: 20133610 DOI: 10.1073/pnas.0907128107] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In Drosophila, Pumilio (Pum) is important for neuronal homeostasis as well as learning and memory. We have recently characterized a mammalian homolog of Pum, Pum2, which is found in discrete RNA-containing particles in the somatodendritic compartment of polarized neurons. In this study, we investigated the role of Pum2 in developing and mature neurons by RNA interference. In immature neurons, loss of Pum2 led to enhanced dendritic outgrowth and arborization. In mature neurons, Pum2 down-regulation resulted in a significant reduction in dendritic spines and an increase in elongated dendritic filopodia. Furthermore, we observed an increase in excitatory synapse markers along dendritic shafts. Electrophysiological analysis of synaptic function of neurons lacking Pum2 revealed an increased miniature excitatory postsynaptic current frequency. We then identified two specific mRNAs coding for a known translational regulator, eIF4E, and for a voltage-gated sodium channel, Scn1a, which interacts with Pum2 in immunoprecipitations from brain lysates. Finally, we show that Pum2 regulates translation of the eIF4E mRNA. Taken together, our data reveal a previously undescribed role for Pum2 in dendrite morphogenesis, synapse function, and translational control.
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Moon IS, Cho SJ, Seog DH, Walikonis R. Neuronal activation increases the density of eukaryotic translation initiation factor 4E mRNA clusters in dendrites of cultured hippocampal neurons. Exp Mol Med 2009; 41:601-10. [PMID: 19381064 DOI: 10.3858/emm.2009.41.8.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Activity-dependent dendritic translation in CNS neurons is important for the synapse-specific provision of proteins that may be necessary for strengthening of synaptic connections. A major rate-limiting factor during protein synthesis is the availability of eukaryotic translation initiation factor 4E (eIF4E), an mRNA 5-cap-binding protein. In this study we show by fluorescence in situ hybridization (FISH) that the mRNA for eIF4E is present in the dendrites of cultured rat hippocampal neurons. Under basal culture conditions, 58.7 +/-11.6% of the eIF4E mRNA clusters localize with or immediately adjacent to PSD-95 clusters. Neuronal activation with KCl (60 mM, 10 min) very significantly increases the number of eIF4E mRNA clusters in dendrites by 50.1 and 74.5% at 2 and 6 h after treatment, respectively. In addition, the proportion of eIF4E mRNA clusters that localize with PSD-95 increases to 74.4+/-7.7% and 77.8+/-7.6% of the eIF4E clusters at 2 and 6 h after KCl treatment, respectively. Our results demonstrate the presence of eIF4E mRNA in dendrites and an activity-dependent increase of these clusters at synaptic sites. This provides a potential mechanism by which protein translation at synapses may be enhanced in response to synaptic stimulation.
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Affiliation(s)
- Il Soo Moon
- Department of Anatomy, College of Medicine, Dongguk University, Gyeongju 780-714, Korea
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36
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Abstract
The localization of mRNAs to subcellular compartments provides a mechanism for regulating gene expression with exquisite temporal and spatial control. Recent studies suggest that a large fraction of mRNAs localize to distinct cytoplasmic domains. In this Review, we focus on cis-acting RNA localization elements, RNA-binding proteins, and the assembly of mRNAs into granules that are transported by molecular motors along cytoskeletal elements to their final destination in the cell.
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Affiliation(s)
- Kelsey C Martin
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095-1737, USA.
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Zeitelhofer M, Karra D, Vessey JP, Jaskic E, Macchi P, Thomas S, Riefler J, Kiebler M, Dahm R. High-efficiency transfection of short hairpin RNAs-encoding plasmids into primary hippocampal neurons. J Neurosci Res 2009; 87:289-300. [DOI: 10.1002/jnr.21840] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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38
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Zetoune AB, Fontanière S, Magnin D, Anczuków O, Buisson M, Zhang CX, Mazoyer S. Comparison of nonsense-mediated mRNA decay efficiency in various murine tissues. BMC Genet 2008; 9:83. [PMID: 19061508 PMCID: PMC2607305 DOI: 10.1186/1471-2156-9-83] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 12/05/2008] [Indexed: 11/26/2022] Open
Abstract
Background The Nonsense-Mediated mRNA Decay (NMD) pathway detects and degrades mRNAs containing premature termination codons, thereby preventing the accumulation of potentially detrimental truncated proteins. Intertissue variation in the efficiency of this mechanism has been suggested, which could have important implications for the understanding of genotype-phenotype correlations in various genetic disorders. However, compelling evidence in favour of this hypothesis is lacking. Here, we have explored this question by measuring the ratio of mutant versus wild-type Men1 transcripts in thirteen tissues from mice carrying a heterozygous truncating mutation in the ubiquitously expressed Men1 gene. Results Significant differences were found between two groups of tissues. The first group, which includes testis, ovary, brain and heart, displays a strong decrease of the nonsense transcript (average ratio of 18% of mutant versus wild-type Men1 transcripts, identical to the value measured in murine embryonic fibroblasts). The second group, comprising lung, intestine and thymus, shows much less pronounced NMD (average ratio of 35%). Importantly, the extent of degradation by NMD does not correlate with the expression level of eleven genes encoding proteins involved in NMD or with the expression level of the Men1 gene. Conclusion Mouse models are an attractive option to evaluate the efficiency of NMD in multiple mammalian tissues and organs, given that it is much easier to obtain these from a mouse than from a single individual carrying a germline truncating mutation. In this study, we have uncovered in the thirteen different murine tissues that we examined up to a two-fold difference in NMD efficiency.
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Affiliation(s)
- Almoutassem B Zetoune
- Laboratoire de Génétique Moléculaire, Signalisation et Cancer UMR5201 CNRS, Equipe Labellisée par Ligue Nationale contre Cance, Université Lyon 1, Université de Lyon, Faculté de Médecine, Lyon, France.
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Zimyanin VL, Belaya K, Pecreaux J, Gilchrist MJ, Clark A, Davis I, St Johnston D. In vivo imaging of oskar mRNA transport reveals the mechanism of posterior localization. Cell 2008; 134:843-53. [PMID: 18775316 PMCID: PMC2585615 DOI: 10.1016/j.cell.2008.06.053] [Citation(s) in RCA: 260] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/30/2008] [Accepted: 06/25/2008] [Indexed: 12/30/2022]
Abstract
oskar mRNA localization to the posterior of the Drosophila oocyte defines where the abdomen and germ cells form in the embryo. Although this localization requires microtubules and the plus end-directed motor, kinesin, its mechanism is controversial and has been proposed to involve active transport to the posterior, diffusion and trapping, or exclusion from the anterior and lateral cortex. By following oskar mRNA particles in living oocytes, we show that the mRNA is actively transported along microtubules in all directions, with a slight bias toward the posterior. This bias is sufficient to localize the mRNA and is reversed in mago, barentsz, and Tropomyosin II mutants, which mislocalize the mRNA anteriorly. Since almost all transport is mediated by kinesin, oskar mRNA localizes by a biased random walk along a weakly polarized cytoskeleton. We also show that each component of the oskar mRNA complex plays a distinct role in particle formation and transport.
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Affiliation(s)
- Vitaly L. Zimyanin
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, CB2 1QN Cambridge, UK
| | - Katsiaryna Belaya
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, CB2 1QN Cambridge, UK
| | | | - Michael J. Gilchrist
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, CB2 1QN Cambridge, UK
| | - Alejandra Clark
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Ilan Davis
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR, UK
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, CB2 1QN Cambridge, UK
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Role of mitogen-activated protein kinase (MAPK) docking sites on Staufen2 protein in dendritic mRNA transport. Biochem Biophys Res Commun 2008; 372:525-9. [PMID: 18492489 DOI: 10.1016/j.bbrc.2008.05.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 05/09/2008] [Indexed: 11/24/2022]
Abstract
Although transport and subsequent translation of dendritic mRNA play an important role in neuronal synaptic plasticity, the underlying mechanisms for modulating dendritic mRNA transport are almost completely unknown. In this study, we identified and characterized an interaction between Staufen2 and mitogen-activated protein kinase (MAPK) with co-immunoprecipitation assays. Staufen2 utilized a docking (D) site to interact with ERK1/2; deleting the D-site decreased colocalization of Staufen2 with immunoreactive ERK1/2 in the cell body regions of cultured hippocampal neurons, and it reduced the amount of Staufen2-containing RNP complexes in the distal dendrites. In addition, the deletion completely abolished the depolarization-induced increase of Staufen2-containing RNP complexes. These results suggest that the MAPK pathway could modulate dendritic mRNA transport through its interaction with Staufen2.
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Ajamian L, Abrahamyan L, Milev M, Ivanov PV, Kulozik AE, Gehring NH, Mouland AJ. Unexpected roles for UPF1 in HIV-1 RNA metabolism and translation. RNA (NEW YORK, N.Y.) 2008; 14:914-27. [PMID: 18369187 PMCID: PMC2327365 DOI: 10.1261/rna.829208] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The HIV-1 ribonucleoprotein (RNP) contains the major structural protein, pr55(Gag), viral genomic RNA, as well as the host protein, Staufen1. In this report, we show that the nonsense-mediated decay (NMD) factor UPF1 is also a component of the HIV-1 RNP. We investigated the role of UPF1 in HIV-1-expressing cells. Depletion of UPF1 by siRNA resulted in a dramatic reduction in steady-state HIV-1 RNA and pr55(Gag). Pr55(Gag) synthesis, but not the cognate genomic RNA, was efficiently rescued by expression of an siRNA-insensitive UPF1, demonstrating that UPF1 positively influences HIV-1 RNA translatability. Conversely, overexpression of UPF1 led to a dramatic up-regulation of HIV-1 expression at the RNA and protein synthesis levels. The effects of UPF1 on HIV-1 RNA stability were observed in the nucleus and cytoplasm and required ongoing translation. We also demonstrate that the effects exerted by UPF1 on HIV-1 expression were dependent on its ATPase activity, but were separable from its role in NMD and did not require interaction with UPF2.
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Affiliation(s)
- Lara Ajamian
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute for Medical Research-Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
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Giorgi C, Yeo GW, Stone ME, Katz DB, Burge C, Turrigiano G, Moore MJ. The EJC factor eIF4AIII modulates synaptic strength and neuronal protein expression. Cell 2007; 130:179-91. [PMID: 17632064 DOI: 10.1016/j.cell.2007.05.028] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 12/23/2006] [Accepted: 05/09/2007] [Indexed: 11/26/2022]
Abstract
Proper neuronal function and several forms of synaptic plasticity are highly dependent on precise control of mRNA translation, particularly in dendrites. We find that eIF4AIII, a core exon junction complex (EJC) component loaded onto mRNAs by pre-mRNA splicing, is associated with neuronal mRNA granules and dendritic mRNAs. eIF4AIII knockdown markedly increases both synaptic strength and GLUR1 AMPA receptor abundance at synapses. eIF4AIII depletion also increases ARC, a protein required for maintenance of long-term potentiation; arc mRNA, one of the most abundant in dendrites, is a natural target for nonsense-mediated decay (NMD). Numerous new NMD candidates, some with potential to affect synaptic activity, were also identified computationally. Two models are presented for how translation-dependent decay pathways such as NMD might advantageously function as critical brakes for protein synthesis in cells such as neurons that are highly dependent on spatially and temporally restricted protein expression.
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Affiliation(s)
- Corinna Giorgi
- Department of Biochemistry, Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454, USA
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Miller LC, Sossin WS. The significance of organellar proteomics for the nervous system. Proteomics Clin Appl 2007; 1:1436-45. [PMID: 21136641 DOI: 10.1002/prca.200700366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Indexed: 12/16/2022]
Abstract
Organellar proteomics is a useful tool for gaining biological insights about structures in the cell. Here, we discuss the tools used in organellar proteomics and the impact of this technique in understanding nervous system function. We will review insights gained from the proteomes of nervous system-specific organelles such as synaptic vesicles and the postsynaptic density. Moreover, we will show how comparison of proteomes between organelles isolated from the nervous system and from other tissues highlight nervous system-specific functions using the examples of clathrin-coated vesicles and RNA granules.
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Affiliation(s)
- Linda C Miller
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Baguet A, Degot S, Cougot N, Bertrand E, Chenard MP, Wendling C, Kessler P, Le Hir H, Rio MC, Tomasetto C. The exon-junction-complex-component metastatic lymph node 51 functions in stress-granule assembly. J Cell Sci 2007; 120:2774-84. [PMID: 17652158 DOI: 10.1242/jcs.009225] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Metastatic lymph node 51 [MLN51 (also known as CASC3)] is a component of the exon junction complex (EJC), which is assembled on spliced mRNAs and plays important roles in post-splicing events. The four proteins of the EJC core, MLN51, MAGOH, Y14 and EIF4AIII shuttle between the cytoplasm and the nucleus. However, unlike the last three, MLN51 is mainly detected in the cytoplasm, suggesting that it plays an additional function in this compartment. In the present study, we show that MLN51 is recruited into cytoplasmic aggregates known as stress granules (SGs) together with the SG-resident proteins, fragile X mental retardation protein (FMRP), poly(A) binding protein (PABP) and poly(A)+ RNA. MLN51 specifically associates with SGs via its C-terminal region, which is dispensable for its incorporation in the EJC. MLN51 does not promote SG formation but its silencing, or the overexpression of a mutant lacking its C-terminal region, alters SG assembly. Finally, in human breast carcinomas, MLN51 is sometimes present in cytoplasmic foci also positive for FMRP and PABP, suggesting that SGs formation occurs in malignant tumours.
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Affiliation(s)
- Aurélie Baguet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie du Cancer, UMR 7104 CNRS/U596 INSERM/Université Louis Pasteur, BP 10142, 67404 Illkirch, C.U. de Strasbourg, France
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45
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Jeong JH, Nam YJ, Kim SY, Kim EG, Jeong J, Kim HK. The transport of Staufen2-containing ribonucleoprotein complexes involves kinesin motor protein and is modulated by mitogen-activated protein kinase pathway. J Neurochem 2007; 102:2073-2084. [PMID: 17587311 DOI: 10.1111/j.1471-4159.2007.04697.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is increasing evidence showing that mRNA is transported to the neuronal dendrites in ribonucleoprotein (RNP) complexes or RNA granules, which are aggregates of mRNA, rRNA, ribosomal proteins, and RNA-binding proteins. In these RNP complexes, Staufen, a double-stranded RNA-binding protein, is believed to be a core component that plays a key role in the dendritic mRNA transport. This study investigated the molecular mechanisms of the dendritic mRNA transport using green fluorescent protein-tagged Staufen2 produced employing a Sindbis viral expression system. The kinesin heavy chain was found to be associated with Staufen2. The inhibition of kinesin resulted in a significant decrease in the level of dendritic transport of the Staufen2-containing RNP complexes in neurons under non-stimulating or stimulating conditions. This suggests that the dendritic transport of the Staufen2-containing RNP complexes use kinesin as a motor protein. A mitogen-activated protein kinase inhibitor, PD98059, inhibited the activity-induced increase in the amount of both the Staufen2-containing RNP complexes and Ca(2+)/calmodulin-dependent protein kinase II alpha-subunit mRNA in the distal dendrites of cultured hippocampal neurons. Overall, these results suggest that dendritic mRNA transport is mediated via the Staufen2 and kinesin motor proteins and might be modulated by the neuronal activity and mitogen-activated protein kinase pathway.
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Affiliation(s)
- Ji-Hye Jeong
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Yeon-Ju Nam
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Seok-Yong Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Eung-Gook Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Jooyoung Jeong
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
| | - Hyong Kyu Kim
- Department of Medicine and Microbiology, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, KoreaDepartment of Medicine and Biochemistry, Medical Research Institute, College of Medicine, Chungbuk National University, Cheongju, Korea
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46
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Abstract
Cytoplasmic RNA localization is a means to create polarity by restricting protein expression to a discrete subcellular location. RNA localization is a multistep process that begins with the recognition of cis-acting sequences within the RNA by specific trans-factors, and RNAs are localized in ribonucleoprotein (RNP) complexes that contain both the RNA and numerous protein components. Components of the localization machinery transport the RNP complex, usually in a translationally repressed state, to a distinct subcellular region, resulting in spatially restricted gene expression. Recent efforts to identify both the cis- and trans-factors required for RNA localization have elucidated RNA-protein interactions that are remodeled during localization.
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Affiliation(s)
- Raymond A Lewis
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
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47
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Barbee SA, Estes PS, Cziko AM, Hillebrand J, Luedeman RA, Coller JM, Johnson N, Howlett IC, Geng C, Ueda R, Brand AH, Newbury SF, Wilhelm JE, Levine RB, Nakamura A, Parker R, Ramaswami M. Staufen- and FMRP-containing neuronal RNPs are structurally and functionally related to somatic P bodies. Neuron 2007; 52:997-1009. [PMID: 17178403 PMCID: PMC1955741 DOI: 10.1016/j.neuron.2006.10.028] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/21/2006] [Accepted: 10/24/2006] [Indexed: 12/19/2022]
Abstract
Local control of mRNA translation modulates neuronal development, synaptic plasticity, and memory formation. A poorly understood aspect of this control is the role and composition of ribonucleoprotein (RNP) particles that mediate transport and translation of neuronal RNAs. Here, we show that staufen- and FMRP-containing RNPs in Drosophila neurons contain proteins also present in somatic "P bodies," including the RNA-degradative enzymes Dcp1p and Xrn1p/Pacman and crucial components of miRNA (argonaute), NMD (Upf1p), and general translational repression (Dhh1p/Me31B) pathways. Drosophila Me31B is shown to participate (1) with an FMRP-associated, P body protein (Scd6p/trailer hitch) in FMRP-driven, argonaute-dependent translational repression in developing eye imaginal discs; (2) in dendritic elaboration of larval sensory neurons; and (3) in bantam miRNA-mediated translational repression in wing imaginal discs. These results argue for a conserved mechanism of translational control critical to neuronal function and open up new experimental avenues for understanding the regulation of mRNA function within neurons.
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Affiliation(s)
- Scott A. Barbee
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Patricia S. Estes
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Anne-Marie Cziko
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Jens Hillebrand
- Smurfit Institute of Genetics and TCIN Lloyd Building, Trinity College Dublin, Dublin-2, Ireland
| | - Rene A. Luedeman
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Jeff M. Coller
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- Howard Hughes Medical Institute, University of Arizona Tucson, Arizona 85721
| | - Nick Johnson
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- Howard Hughes Medical Institute, University of Arizona Tucson, Arizona 85721
| | - Iris C. Howlett
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Cuiyun Geng
- Institute for Cellular and Molecular Biology Section of Molecular Cell and Developmental Biology, The University of Texas at Austin 1 University Station Austin, Texas 78712
| | - Ryu Ueda
- Invertebrate Genetics Lab, Genetic Strains Research Center, National Institute of Genetics (NIG) 1111 Yata Mishima, Shizuoka 411-8540, Japan
| | - Andrea H. Brand
- Wellcome/CRC Institute and Department of Genetics, University of Cambridge, Cambridge CB2 IQR, United Kingdom
| | - Sarah F. Newbury
- Institute of Cell and Molecular Biosciences, University of Newcastle, The Medical School Framlington Place, Newcastle-upon-Tyne, United Kingdom
| | - James E. Wilhelm
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego La Jolla, California 92093
| | - Richard B. Levine
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
| | - Akira Nakamura
- Laboratory for Germline Development, RIKEN Center for Developmental Biology, 2-2-3 Minatojimaminamimachi Chuo-ku, Kobe 650-0047 Japan
| | - Roy Parker
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- Howard Hughes Medical Institute, University of Arizona Tucson, Arizona 85721
- *Correspondence: (R.P.), . edu (M.R.)
| | - Mani Ramaswami
- Department of Molecular and Cellular Biology, University of Arizona Tucson, Arizona 85721
- ARL Division of Neurobiology, University of Arizona Tucson, Arizona 85721
- Smurfit Institute of Genetics and TCIN Lloyd Building, Trinity College Dublin, Dublin-2, Ireland
- *Correspondence: (R.P.), . edu (M.R.)
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48
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Abstract
From yeast to mammals, evidence has emerged in recent years highlighting the essential role played by the nuclear "history" of a messenger RNA in determining its cytoplasmic fate. mRNA localization, translation and stability in the cytoplasm are often pre-destined in the nucleus, and directed by the composition and architecture of nuclear assembled mRNA-protein complexes. In this review we focus on nuclear-acquired RNA-binding proteins and complexes that participate in determining the journey of localized mRNAs.
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Affiliation(s)
- Corinna Giorgi
- Department of Biochemistry, Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454, USA
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49
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Bono F, Ebert J, Lorentzen E, Conti E. The crystal structure of the exon junction complex reveals how it maintains a stable grip on mRNA. Cell 2006; 126:713-25. [PMID: 16923391 DOI: 10.1016/j.cell.2006.08.006] [Citation(s) in RCA: 313] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 07/31/2006] [Accepted: 08/09/2006] [Indexed: 11/30/2022]
Abstract
The exon junction complex (EJC) plays a major role in posttranscriptional regulation of mRNA in metazoa. The EJC is deposited onto mRNA during splicing and is transported to the cytoplasm where it influences translation, surveillance, and localization of the spliced mRNA. The complex is formed by the association of four proteins (eIF4AIII, Barentsz [Btz], Mago, and Y14), mRNA, and ATP. The 2.2 A resolution structure of the EJC reveals how it stably locks onto mRNA. The DEAD-box protein eIF4AIII encloses an ATP molecule and provides the binding sites for six ribonucleotides. Btz wraps around eIF4AIII and stacks against the 5' nucleotide. An intertwined network of interactions anchors Mago-Y14 and Btz at the interface between the two domains of eIF4AIII, effectively stabilizing the ATP bound state. Comparison with the structure of the eIF4AIII-Btz subcomplex that we have also determined reveals that large conformational changes are required upon EJC assembly and disassembly.
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Affiliation(s)
- Fulvia Bono
- European Molecular Biology Laboratory, EMBL, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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50
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Abstract
The transport of messenger RNAs (mRNAs) in neurons serves many purposes. During development, trafficking of mRNAs to both axonal and dendritic growth cones regulates neuronal growth. After synapse formation, mRNAs continue to be transported to dendrites both as a mechanism for the localization of proteins to specific compartments and as a substrate for local translational regulation of synaptic plasticity. Finally, activity-dependent mRNAs are transported quickly to dendrites after transcription. Determining how mRNAs are transported and specifically translated in these different paradigms is a major unanswered question. Addressing this question is also complicated by the presence of many other RNA processing and storage centers that may not be involved in transport but share components with the transport structures. In the present review, we will discuss several recent studies addressing mechanisms of mRNA transport in neurons, as well as proteomic characterization of mRNA transporting structures in neurons. We define two types of RNA transport structures in neurons, transport particles and RNA granules and distinguish them by the presence or absence of ribosomes. We will present a number of different molecular models for how mRNAs are repressed during transport, and how these may affect the regulation of local translation in neurons.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, McGill University, Montreal Neurological Institute, BT 110, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
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