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Wijegunawardana D, Nayak A, Vishal SS, Venkatesh N, Gopal PP. Ataxin-2 polyglutamine expansions aberrantly sequester TDP-43 ribonucleoprotein condensates disrupting mRNA transport and local translation in neurons. Dev Cell 2024:S1534-5807(24)00572-0. [PMID: 39419034 DOI: 10.1016/j.devcel.2024.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/10/2024] [Accepted: 09/19/2024] [Indexed: 10/19/2024]
Abstract
Altered RNA metabolism and misregulation of transactive response DNA-binding protein of 43 kDa (TDP-43), an essential RNA-binding protein (RBP), define amyotrophic lateral sclerosis (ALS). Intermediate-length polyglutamine (polyQ) expansions of Ataxin-2, a like-Sm (LSm) RBP, are associated with increased risk for ALS, but the underlying biological mechanisms remain unknown. Here, we studied the spatiotemporal dynamics and mRNA regulatory functions of TDP-43 and Ataxin-2 ribonucleoprotein (RNP) condensates in rodent (rat) primary cortical neurons and mouse motor neuron axons in vivo. We report that Ataxin-2 polyQ expansions aberrantly sequester TDP-43 within RNP condensates and disrupt both its motility along the axon and liquid-like properties. We provide evidence that Ataxin-2 governs motility and translation of neuronal RNP condensates and that Ataxin-2 polyQ expansions fundamentally perturb spatial localization of mRNA and suppress local translation. Overall, our results support a model in which Ataxin-2 polyQ expansions disrupt stability, localization, and/or translation of critical axonal and cytoskeletal mRNAs, particularly important for motor neuron integrity.
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Affiliation(s)
- Denethi Wijegunawardana
- Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA; Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA
| | - Asima Nayak
- Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Sonali S Vishal
- Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Neha Venkatesh
- Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA; College of Arts and Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Pallavi P Gopal
- Department of Pathology, Yale School of Medicine, New Haven, CT 06510, USA; Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, USA; Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT 06510, USA.
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2
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Naskar A, Nayak A, Salaikumaran MR, Vishal SS, Gopal PP. Phase separation and pathologic transitions of RNP condensates in neurons: implications for amyotrophic lateral sclerosis, frontotemporal dementia and other neurodegenerative disorders. Front Mol Neurosci 2023; 16:1242925. [PMID: 37720552 PMCID: PMC10502346 DOI: 10.3389/fnmol.2023.1242925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/21/2023] [Indexed: 09/19/2023] Open
Abstract
Liquid-liquid phase separation results in the formation of dynamic biomolecular condensates, also known as membrane-less organelles, that allow for the assembly of functional compartments and higher order structures within cells. Multivalent, reversible interactions between RNA-binding proteins (RBPs), including FUS, TDP-43, and hnRNPA1, and/or RNA (e.g., RBP-RBP, RBP-RNA, RNA-RNA), result in the formation of ribonucleoprotein (RNP) condensates, which are critical for RNA processing, mRNA transport, stability, stress granule assembly, and translation. Stress granules, neuronal transport granules, and processing bodies are examples of cytoplasmic RNP condensates, while the nucleolus and Cajal bodies are representative nuclear RNP condensates. In neurons, RNP condensates promote long-range mRNA transport and local translation in the dendrites and axon, and are essential for spatiotemporal regulation of gene expression, axonal integrity and synaptic function. Mutations of RBPs and/or pathologic mislocalization and aggregation of RBPs are hallmarks of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease. ALS/FTD-linked mutations of RBPs alter the strength and reversibility of multivalent interactions with other RBPs and RNAs, resulting in aberrant phase transitions. These aberrant RNP condensates have detrimental functional consequences on mRNA stability, localization, and translation, and ultimately lead to compromised axonal integrity and synaptic function in disease. Pathogenic protein aggregation is dependent on various factors, and aberrant dynamically arrested RNP condensates may serve as an initial nucleation step for pathologic aggregate formation. Recent studies have focused on identifying mechanisms by which neurons resolve phase transitioned condensates to prevent the formation of pathogenic inclusions/aggregates. The present review focuses on the phase separation of neurodegenerative disease-linked RBPs, physiological functions of RNP condensates, and the pathologic role of aberrant phase transitions in neurodegenerative disease, particularly ALS/FTD. We also examine cellular mechanisms that contribute to the resolution of aberrant condensates in neurons, and potential therapeutic approaches to resolve aberrantly phase transitioned condensates at a molecular level.
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Affiliation(s)
- Aditi Naskar
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Asima Nayak
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | | | - Sonali S. Vishal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Pallavi P. Gopal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT, United States
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3
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Hildebrandt RP, Moss KR, Janusz-Kaminska A, Knudson LA, Denes LT, Saxena T, Boggupalli DP, Li Z, Lin K, Bassell GJ, Wang ET. Muscleblind-like proteins use modular domains to localize RNAs by riding kinesins and docking to membranes. Nat Commun 2023; 14:3427. [PMID: 37296096 PMCID: PMC10256740 DOI: 10.1038/s41467-023-38923-6] [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: 08/23/2022] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
RNA binding proteins (RBPs) act as critical facilitators of spatially regulated gene expression. Muscleblind-like (MBNL) proteins, implicated in myotonic dystrophy and cancer, localize RNAs to myoblast membranes and neurites through unknown mechanisms. We find that MBNL forms motile and anchored granules in neurons and myoblasts, and selectively associates with kinesins Kif1bα and Kif1c through its zinc finger (ZnF) domains. Other RBPs with similar ZnFs associate with these kinesins, implicating a motor-RBP specificity code. MBNL and kinesin perturbation leads to widespread mRNA mis-localization, including depletion of Nucleolin transcripts from neurites. Live cell imaging and fractionation reveal that the unstructured carboxy-terminal tail of MBNL1 allows for anchoring at membranes. An approach, termed RBP Module Recruitment and Imaging (RBP-MRI), reconstitutes kinesin- and membrane-recruitment functions using MBNL-MS2 coat protein fusions. Our findings decouple kinesin association, RNA binding, and membrane anchoring functions of MBNL while establishing general strategies for studying multi-functional, modular domains of RBPs.
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Affiliation(s)
- Ryan P Hildebrandt
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kathryn R Moss
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Luke A Knudson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Lance T Denes
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Tanvi Saxena
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Devi Prasad Boggupalli
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Zhuangyue Li
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Kun Lin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Eric T Wang
- Department of Molecular Genetics & Microbiology, Center for Neurogenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
- Myology Institute, University of Florida, Gainesville, FL, USA.
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4
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Piol D, Robberechts T, Da Cruz S. Lost in local translation: TDP-43 and FUS in axonal/neuromuscular junction maintenance and dysregulation in amyotrophic lateral sclerosis. Neuron 2023; 111:1355-1380. [PMID: 36963381 DOI: 10.1016/j.neuron.2023.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/21/2022] [Accepted: 02/16/2023] [Indexed: 03/26/2023]
Abstract
Key early features of amyotrophic lateral sclerosis (ALS) are denervation of neuromuscular junctions and axonal degeneration. Motor neuron homeostasis relies on local translation through controlled regulation of axonal mRNA localization, transport, and stability. Yet the composition of the local transcriptome, translatome (mRNAs locally translated), and proteome during health and disease remains largely unexplored. This review covers recent discoveries on axonal translation as a critical mechanism for neuronal maintenance/survival. We focus on two RNA binding proteins, transactive response DNA binding protein-43 (TDP-43) and fused in sarcoma (FUS), whose mutations cause ALS and frontotemporal dementia (FTD). Emerging evidence points to their essential role in the maintenance of axons and synapses, including mRNA localization, transport, and local translation, and whose dysfunction may contribute to ALS. Finally, we describe recent advances in omics-based approaches mapping compartment-specific local RNA and protein compositions, which will be invaluable to elucidate fundamental local processes and identify key targets for therapy development.
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Affiliation(s)
- Diana Piol
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Tessa Robberechts
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Sandrine Da Cruz
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium.
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5
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Wijegunawardana D, Vishal SS, Venkatesh N, Gopal PP. Ataxin-2 polyglutamine expansions aberrantly sequester TDP-43, drive ribonucleoprotein condensate transport dysfunction and suppress local translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526372. [PMID: 36778347 PMCID: PMC9915502 DOI: 10.1101/2023.01.30.526372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Altered RNA metabolism is a common pathogenic mechanism linked to familial and sporadic Amyotrophic lateral sclerosis (ALS). ALS is characterized by mislocalization and aggregation of TDP-43, an RNA-binding protein (RBP) with multiple roles in post-transcriptional RNA processing. Recent studies have identified genetic interactions between TDP-43 and Ataxin-2, a polyglutamine (polyQ) RBP in which intermediate length polyQ expansions confer increased ALS risk. Here, we used live-cell confocal imaging, photobleaching and translation reporter assays to study the localization, transport dynamics and mRNA regulatory functions of TDP-43/Ataxin-2 in rodent primary cortical neurons. We show that Ataxin-2 polyQ expansions aberrantly sequester TDP-43 within ribonucleoprotein (RNP) condensates, and disrupt both its motility along the axon and liquid-like properties. Our data suggest that Ataxin-2 governs motility and translation of neuronal RNP condensates and that Ataxin-2 polyQ expansions fundamentally perturb spatial localization of mRNA and suppress local translation. Overall, these results indicate Ataxin-2 polyQ expansions have detrimental effects on stability, localization, and translation of transcripts critical for axonal and cytoskeletal integrity, particularly important for motor neurons.
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6
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Charif SE, Luchelli L, Vila A, Blaustein M, Igaz LM. Cytoplasmic Expression of the ALS/FTD-Related Protein TDP-43 Decreases Global Translation Both in vitro and in vivo. Front Cell Neurosci 2020; 14:594561. [PMID: 33363456 PMCID: PMC7752804 DOI: 10.3389/fncel.2020.594561] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022] Open
Abstract
TDP-43 is a major component of cytoplasmic inclusions observed in neurodegenerative diseases like frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). To further understand the role of TDP-43 in mRNA/protein metabolism and proteostasis, we used a combined approach with cellular and animal models overexpressing a cytoplasmic form of human TDP-43 (TDP-43-ΔNLS), recapitulating ALS/FTD features. We applied in HEK293 cells a method for labeling de novo translation, surface sensing of translation (SUnSET), based on puromycin (PURO) incorporation. While control cells displayed robust puromycilation, TDP-43-ΔNLS transfected cells exhibited reduced ongoing protein synthesis. Next, by using a transgenic mouse overexpressing cytoplasmic TDP-43 in the forebrain (TDP-43-ΔNLS mice) we assessed whether cytoplasmic TDP-43 regulates global translation in vivo. Polysome profiling of brain cortices from transgenic mice showed a shift toward non-polysomal fractions as compared to wild-type littermates, indicating a decrease in global translation. Lastly, cellular level translational assessment by SUNSET was performed in TDP-43-ΔNLS mice brain slices. Control mice slices incubated with PURO exhibited robust cytoplasmic PURO signal in layer 5 neurons from motor cortex, and normal nuclear TDP-43 staining. Neurons in TDP-43-ΔNLS mice slices incubated with PURO exhibited high cytoplasmic expression of TDP-43 and reduced puromycilation respect to control mice. These in vitro and in vivo results indicate that cytoplasmic TDP-43 decreases global translation and potentially cause functional/cytotoxic effects as observed in ALS/FTD. Our study provide in vivo evidence (by two independent and complementary methods) for a role of mislocalized TDP-43 in the regulation of global mRNA translation, with implications for TDP-43 proteinopathies.
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Affiliation(s)
- Santiago E Charif
- Instituto de Fisiología y Biofísica "Bernardo Houssay", (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Luciana Luchelli
- Instituto de Fisiología y Biofísica "Bernardo Houssay", (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Antonella Vila
- Instituto de Biociencias, Biotecnología y Biología Traslacional, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Matías Blaustein
- Instituto de Biociencias, Biotecnología y Biología Traslacional, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lionel M Igaz
- Instituto de Fisiología y Biofísica "Bernardo Houssay", (IFIBIO-Houssay), Grupo de Neurociencia de Sistemas, Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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7
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Klein ME, Younts TJ, Cobo CF, Buxbaum AR, Aow J, Erdjument-Bromage H, Richard S, Malinow R, Neubert TA, Singer RH, Castillo PE, Jordan BA. Sam68 Enables Metabotropic Glutamate Receptor-Dependent LTD in Distal Dendritic Regions of CA1 Hippocampal Neurons. Cell Rep 2020; 29:1789-1799.e6. [PMID: 31722197 PMCID: PMC6871770 DOI: 10.1016/j.celrep.2019.10.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/15/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022] Open
Abstract
The transport and translation of dendritic mRNAs by RNA-binding proteins (RBPs) allows for spatially restricted gene expression in neuronal processes. Although local translation in neuronal dendrites is now well documented, there is little evidence for corresponding effects on local synaptic function. Here, we report that the RBP Sam68 promotes the localization and translation of Arc mRNA preferentially in distal dendrites of rodent hippocampal CA1 pyramidal neurons. Consistent with Arc function in translation-dependent synaptic plasticity, we find that Sam68 knockout (KO) mice display impaired metabotropic glutamate-receptor-dependent long-term depression (mGluR-LTD) and impaired structural plasticity exclusively at distal Schaffer-collateral synapses. Moreover, by using quantitative proteomics, we find that the Sam68 interactome contains numerous regulators of mRNA translation and synaptic function. This work identifies an important player in Arc expression, provides a general framework for Sam68 regulation of protein synthesis, and uncovers a mechanism that enables the precise spatiotemporal expression of long-term plasticity throughout neurons.
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Affiliation(s)
- Matthew E Klein
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Thomas J Younts
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Carmen Freire Cobo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Adina R Buxbaum
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Jonathan Aow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Hediye Erdjument-Bromage
- Department of Cell Biology and Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Stéphane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research and Departments of Oncology and Medicine, McGill University, Montréal, QC H3T 1E2, Canada
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Thomas A Neubert
- Department of Cell Biology and Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Robert H Singer
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Janelia Research Campus of the Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Bryen A Jordan
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
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8
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Phenotypic Suppression of ALS/FTD-Associated Neurodegeneration Highlights Mechanisms of Dysfunction. J Neurosci 2020; 39:8217-8224. [PMID: 31619490 DOI: 10.1523/jneurosci.1159-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/05/2019] [Accepted: 08/07/2019] [Indexed: 12/14/2022] Open
Abstract
A fundamental question regarding the etiology of amyotrophic lateral sclerosis (ALS) is whether the various gene mutations associated with the disease converge on a single molecular pathway or act through multiple pathways to trigger neurodegeneration. Notably, several of the genes and cellular processes implicated in ALS have also been linked to frontotemporal dementia (FTD), suggesting these two diseases share common origins with varied clinical presentations. Scientists are rapidly identifying ALS/FTD suppressors that act on conserved pathways from invertebrates to vertebrates to alleviate degeneration. The elucidation of such genetic modifiers provides insight into the molecular pathways underlying this rapidly progressing neurodegenerative disease, while also revealing new targets for therapeutic development.
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9
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Maccallini P, Bavasso F, Scatolini L, Bucciarelli E, Noviello G, Lisi V, Palumbo V, D'Angeli S, Cacchione S, Cenci G, Ciapponi L, Wakefield JG, Gatti M, Raffa GD. Intimate functional interactions between TGS1 and the Smn complex revealed by an analysis of the Drosophila eye development. PLoS Genet 2020; 16:e1008815. [PMID: 32453722 PMCID: PMC7289441 DOI: 10.1371/journal.pgen.1008815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/11/2020] [Accepted: 04/30/2020] [Indexed: 11/27/2022] Open
Abstract
Trimethylguanosine synthase 1 (TGS1) is a conserved enzyme that mediates formation of the trimethylguanosine cap on several RNAs, including snRNAs and telomerase RNA. Previous studies have shown that TGS1 binds the Survival Motor Neuron (SMN) protein, whose deficiency causes spinal muscular atrophy (SMA). Here, we analyzed the roles of the Drosophila orthologs of the human TGS1 and SMN genes. We show that the Drosophila TGS1 protein (dTgs1) physically interacts with all subunits of the Drosophila Smn complex (Smn, Gem2, Gem3, Gem4 and Gem5), and that a human TGS1 transgene rescues the mutant phenotype caused by dTgs1 loss. We demonstrate that both dTgs1 and Smn are required for viability of retinal progenitor cells and that downregulation of these genes leads to a reduced eye size. Importantly, overexpression of dTgs1 partially rescues the eye defects caused by Smn depletion, and vice versa. These results suggest that the Drosophila eye model can be exploited for screens aimed at the identification of genes and drugs that modify the phenotypes elicited by Tgs1 and Smn deficiency. These modifiers could help to understand the molecular mechanisms underlying SMA pathogenesis and devise new therapies for this genetic disease. We explored the functional relationships between TGS1 and SMN using Drosophila as model organism. TGS1 is an enzyme that modifies the structure of the 5’-end of several RNAs, including telomerase RNA and the small nuclear RNAs (snRNAs) that are required for messenger RNA maturation. The SMN protein regulates snRNAs biogenesis and mutations in human SMN cause Spinal Muscular Atrophy (SMA), a devastating disorder characterized by neurodegeneration, progressive paralysis and death. We show that mutations in the Drosophila TGS1 (dTgs1) gene cause lethality, which is rescued by a human TGS1 transgene. We also show that the dTgs1 protein physically interacts with all subunits of the Smn complex, and that downregulation of either dTgs1 or Smn leads to a reduced Drosophila eye size. Notably, overexpression of dTgs1 partially rescues the eye defects caused by Smn knockdown, and vice versa, indicating that these genes cooperate in eye development. These results suggest that the eye model can be exploited for screens aimed at detection of chemical and genetic modifiers of the eye mutant phenotype elicited by dTgs1 and Smn deficiency, providing new clues about SMA pathogenesis and potential therapies.
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Affiliation(s)
- Paolo Maccallini
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Francesca Bavasso
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Livia Scatolini
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | | | - Gemma Noviello
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Veronica Lisi
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Valeria Palumbo
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Simone D'Angeli
- Dipartimento di Biologia Ambientale, Sapienza University of Rome, Rome, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - Giovanni Cenci
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
- Fondazione Cenci Bolognetti, Istituto Pasteur, Rome, Italy
| | - Laura Ciapponi
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
| | - James G. Wakefield
- Biosciences/Living Systems Institute, College of Life and Environmental Sciences, University of Exeter, United Kingdom
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
- Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Rome, Italy
- * E-mail: (MG); (GDR)
| | - Grazia Daniela Raffa
- Dipartimento di Biologia e Biotecnologie “C Darwin”, Sapienza University of Rome, Rome, Italy
- * E-mail: (MG); (GDR)
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10
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Borbolis F, Rallis J, Kanatouris G, Kokla N, Karamalegkos A, Vasileiou C, Vakaloglou KM, Diallinas G, Stravopodis DJ, Zervas CG, Syntichaki P. mRNA decapping is an evolutionarily conserved modulator of neuroendocrine signaling that controls development and ageing. eLife 2020; 9:e53757. [PMID: 32366357 PMCID: PMC7200159 DOI: 10.7554/elife.53757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 04/22/2020] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic 5'-3' mRNA decay plays important roles during development and in response to stress, regulating gene expression post-transcriptionally. In Caenorhabditis elegans, deficiency of DCAP-1/DCP1, the essential co-factor of the major cytoplasmic mRNA decapping enzyme, impacts normal development, stress survival and ageing. Here, we show that overexpression of dcap-1 in neurons of worms is sufficient to increase lifespan through the function of the insulin/IGF-like signaling and its effector DAF-16/FOXO transcription factor. Neuronal DCAP-1 affects basal levels of INS-7, an ageing-related insulin-like peptide, which acts in the intestine to determine lifespan. Short-lived dcap-1 mutants exhibit a neurosecretion-dependent upregulation of intestinal ins-7 transcription, and diminished nuclear localization of DAF-16/FOXO. Moreover, neuronal overexpression of DCP1 in Drosophila melanogaster confers longevity in adults, while neuronal DCP1 deficiency shortens lifespan and affects wing morphogenesis, cell non-autonomously. Our genetic analysis in two model-organisms suggests a critical and conserved function of DCAP-1/DCP1 in developmental events and lifespan modulation.
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Affiliation(s)
- Fivos Borbolis
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - John Rallis
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - George Kanatouris
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - Nikolitsa Kokla
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - Antonis Karamalegkos
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - Christina Vasileiou
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
- Department of Molecular Biology and Genetics, Democritus University of ThraceAlex/polisGreece
| | - Katerina M Vakaloglou
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
| | - George Diallinas
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - Dimitrios J Stravopodis
- Department of Biology, School of Science, National and Kapodistrian University of AthensAthensGreece
| | - Christos G Zervas
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
| | - Popi Syntichaki
- Biomedical Research Foundation of the Academy of Athens, Center of Basic ResearchAthensGreece
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11
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Simbriger K, Amorim IS, Chalkiadaki K, Lach G, Jafarnejad SM, Khoutorsky A, Gkogkas CG. Monitoring translation in synaptic fractions using a ribosome profiling strategy. J Neurosci Methods 2019; 329:108456. [PMID: 31610213 PMCID: PMC6899497 DOI: 10.1016/j.jneumeth.2019.108456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/13/2019] [Accepted: 10/05/2019] [Indexed: 11/26/2022]
Abstract
Ribosome profiling in synaptosomes. Transcriptome and translatome profiling from synaptic fractions. Powerful tool to study local translation at the synapse.
Background The aim of this study was to develop a method to study genome-wide local translation in biochemically isolated synaptic fractions (synaptoneurosomes). This methodology is of particular interest for neurons, due to the cardinal role of local translational control in neuronal sub-compartments, such as dendrites, for plasticity, learning, memory, and for disorders of the nervous system. New method We combined established methods for purifying synaptoneurosomes with translational profiling (ribosome profiling), a method that employs unbiased next generation sequencing to simultaneously assess transcription and translation in a single sample. Results The two existing methods are compatible to use in combination and yield high quality sequencing data, which are specific to synaptic compartments. This new protocol provides an easy to implement workflow, which combines biochemical isolation of synaptoneurosomes of varying levels of purity (crude or Percoll gradient purified) with the use of a commercial kit to generate sequencing libraries. Comparison with existing methods Compared to previous studies of the synaptic translatome, our method shows less contamination with non-neuronal cell types or non-synaptic compartments, increasing the specificity of the data obtained. Conclusions Combining the isolation of functional synaptic units with ribosome profiling offers a powerful tool to study local translation in synaptic compartments both in health and disease.
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Affiliation(s)
- Konstanze Simbriger
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK; Patrick Wild Centre, EH8 9XD, Edinburgh, Scotland, UK
| | - Inês S Amorim
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK; Patrick Wild Centre, EH8 9XD, Edinburgh, Scotland, UK
| | - Kleanthi Chalkiadaki
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK; Patrick Wild Centre, EH8 9XD, Edinburgh, Scotland, UK
| | - Gilliard Lach
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK; Patrick Wild Centre, EH8 9XD, Edinburgh, Scotland, UK
| | - Seyed Mehdi Jafarnejad
- Centre for Cancer Research and Cell Biology, The Queen's University of Belfast, BT9 7AE, Belfast, Northern Ireland, UK
| | - Arkady Khoutorsky
- Department of Anesthesia, Faculty of Dentistry and Alan Edwards Centre for Research on Pain, McGill University, H3A 0G1, Montréal, QC, Canada
| | - Christos G Gkogkas
- Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD, Edinburgh, Scotland, UK; Patrick Wild Centre, EH8 9XD, Edinburgh, Scotland, UK; Simons Initiative for the Developing Brain, EH8 9XD, Edinburgh, Scotland, UK.
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12
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Farris S, Ward JM, Carstens KE, Samadi M, Wang Y, Dudek SM. Hippocampal Subregions Express Distinct Dendritic Transcriptomes that Reveal Differences in Mitochondrial Function in CA2. Cell Rep 2019; 29:522-539.e6. [PMID: 31597108 PMCID: PMC6894405 DOI: 10.1016/j.celrep.2019.08.093] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/15/2019] [Accepted: 08/27/2019] [Indexed: 12/15/2022] Open
Abstract
RNA localization is one mechanism neurons use to spatially and temporally regulate gene expression at synapses. Here, we test the hypothesis that cells exhibiting distinct forms of synaptic plasticity will have differences in dendritically localized RNAs. Indeed, we discover that each major subregion of the adult mouse hippocampus expresses a unique complement of dendritic RNAs. Specifically, we describe more than 1,000 differentially expressed dendritic RNAs, suggesting that RNA localization and local translation are regulated in a cell type-specific manner. Furthermore, by focusing Gene Ontology analyses on the plasticity-resistant CA2, we identify an enrichment of mitochondria-associated pathways in CA2 cell bodies and dendrites, and we provide functional evidence that these pathways differentially influence plasticity and mitochondrial respiration in CA2. These data indicate that differences in dendritic transcriptomes may regulate cell type-specific properties important for learning and memory and may influence region-specific differences in disease pathology.
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Affiliation(s)
- Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - James M Ward
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Kelly E Carstens
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Mahsa Samadi
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Yu Wang
- Cellular and Molecular Pathology, National Toxicology Program, NIH, Research Triangle Park, NC 27709, USA
| | - Serena M Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
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13
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Rossoll W, Bassell GJ. Crosstalk of Local Translation and Mitochondria: Powering Plasticity in Axons and Dendrites. Neuron 2019; 101:204-206. [PMID: 30653934 DOI: 10.1016/j.neuron.2018.12.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two papers in Cell uncover reciprocal crosstalk of local translation and mitochondria in neurons. Rangaraju et al. (2019) observe tethered compartments of stable mitochondria in dendrites that provide a local energy supply for mRNA translation at synapses. Cioni et al. (2019) report a novel association of axonal RNA granules with Rab7a-late endosomes that provides a platform for local translation supporting mitochondria.
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Affiliation(s)
- Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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14
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López-Erauskin J, Tadokoro T, Baughn MW, Myers B, McAlonis-Downes M, Chillon-Marinas C, Asiaban JN, Artates J, Bui AT, Vetto AP, Lee SK, Le AV, Sun Y, Jambeau M, Boubaker J, Swing D, Qiu J, Hicks GG, Ouyang Z, Fu XD, Tessarollo L, Ling SC, Parone PA, Shaw CE, Marsala M, Lagier-Tourenne C, Cleveland DW, Da Cruz S. ALS/FTD-Linked Mutation in FUS Suppresses Intra-axonal Protein Synthesis and Drives Disease Without Nuclear Loss-of-Function of FUS. Neuron 2018; 100:816-830.e7. [PMID: 30344044 PMCID: PMC6277851 DOI: 10.1016/j.neuron.2018.09.044] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/11/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022]
Abstract
Through the generation of humanized FUS mice expressing full-length human FUS, we identify that when expressed at near endogenous murine FUS levels, both wild-type and ALS-causing and frontotemporal dementia (FTD)-causing mutations complement the essential function(s) of murine FUS. Replacement of murine FUS with mutant, but not wild-type, human FUS causes stress-mediated induction of chaperones, decreased expression of ion channels and transporters essential for synaptic function, and reduced synaptic activity without loss of nuclear FUS or its cytoplasmic aggregation. Most strikingly, accumulation of mutant human FUS is shown to activate an integrated stress response and to inhibit local, intra-axonal protein synthesis in hippocampal neurons and sciatic nerves. Collectively, our evidence demonstrates that human ALS/FTD-linked mutations in FUS induce a gain of toxicity that includes stress-mediated suppression in intra-axonal translation, synaptic dysfunction, and progressive age-dependent motor and cognitive disease without cytoplasmic aggregation, altered nuclear localization, or aberrant splicing of FUS-bound pre-mRNAs. VIDEO ABSTRACT.
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Affiliation(s)
- Jone López-Erauskin
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Takahiro Tadokoro
- Department of Anesthesiology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Michael W Baughn
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Brian Myers
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Melissa McAlonis-Downes
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Carlos Chillon-Marinas
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Joshua N Asiaban
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jonathan Artates
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Anh T Bui
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Anne P Vetto
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Sandra K Lee
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Ai Vy Le
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Ying Sun
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Mélanie Jambeau
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jihane Boubaker
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Deborah Swing
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Jinsong Qiu
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Geoffrey G Hicks
- Regenerative Medicine Program and Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, R3T 2N2, Canada
| | - Zhengyu Ouyang
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Shuo-Chien Ling
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Philippe A Parone
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, SE5 9NU London, U.K; Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Martin Marsala
- Department of Anesthesiology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Clotilde Lagier-Tourenne
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093, USA.
| | - Sandrine Da Cruz
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA 92093, USA.
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15
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Chaytow H, Huang YT, Gillingwater TH, Faller KME. The role of survival motor neuron protein (SMN) in protein homeostasis. Cell Mol Life Sci 2018; 75:3877-3894. [PMID: 29872871 PMCID: PMC6182345 DOI: 10.1007/s00018-018-2849-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/11/2022]
Abstract
Ever since loss of survival motor neuron (SMN) protein was identified as the direct cause of the childhood inherited neurodegenerative disorder spinal muscular atrophy, significant efforts have been made to reveal the molecular functions of this ubiquitously expressed protein. Resulting research demonstrated that SMN plays important roles in multiple fundamental cellular homeostatic pathways, including a well-characterised role in the assembly of the spliceosome and biogenesis of ribonucleoproteins. More recent studies have shown that SMN is also involved in other housekeeping processes, including mRNA trafficking and local translation, cytoskeletal dynamics, endocytosis and autophagy. Moreover, SMN has been shown to influence mitochondria and bioenergetic pathways as well as regulate function of the ubiquitin-proteasome system. In this review, we summarise these diverse functions of SMN, confirming its key role in maintenance of the homeostatic environment of the cell.
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Affiliation(s)
- Helena Chaytow
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Yu-Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK.
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK.
| | - Kiterie M E Faller
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
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16
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Zavolan M, Gerber AP. Mirroring the multifaceted role of
RNA
and its partners in gene expression. FEBS Lett 2018; 592:2825-2827. [DOI: 10.1002/1873-3468.13230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - André P. Gerber
- Faculty of Health and Medical Sciences Department of Microbial Sciences School of Biosciences and Medicine University of Surrey Guildford UK
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17
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Surrey V, Zöller C, Lork AA, Moradi M, Balk S, Dombert B, Saal-Bauernschubert L, Briese M, Appenzeller S, Fischer U, Jablonka S. Impaired Local Translation of β-actin mRNA in Ighmbp2-Deficient Motoneurons: Implications for Spinal Muscular Atrophy with respiratory Distress (SMARD1). Neuroscience 2018; 386:24-40. [DOI: 10.1016/j.neuroscience.2018.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/03/2018] [Accepted: 06/11/2018] [Indexed: 12/31/2022]
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18
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Abstract
Ataxin-2 is an RNA-binding protein involved in translation regulation and mutated in neurodegenerative diseases, including ALS. In this issue of Neuron, Bakthavachalu et al. (2018) demonstrate that higher-order ataxin-2 RNA/protein assemblies are necessary for both translation-dependent learning and ALS-associated neurodegeneration in Drosophila.
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Affiliation(s)
- Lindsay A Becker
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Neurosciences Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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19
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Zhou Y, Dong F, Mao Y. Control of CNS functions by RNA-binding proteins in neurological diseases. ACTA ACUST UNITED AC 2018; 4:301-313. [PMID: 30410853 DOI: 10.1007/s40495-018-0140-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Purpose of Review This review summarizes recent studies on the molecular mechanisms of RNA binding proteins (RBPs) that control neurological functions and pathogenesis in various neurodevelopmental and neurodegenerative diseases, including autism spectrum disorders, schizophrenia, Alzheimer's disease, amyotrophic lateral sclerosis, frontotemporal dementia, and spinocerebellar ataxia. Recent Findings RBPs are critical players in gene expression that regulate every step of posttranscriptional modifications. Recent genome-wide approaches revealed that many proteins associate with RNA, but do not contain any known RNA binding motifs. Additionally, many causal and risk genes of neurodevelopmental and neurodegenerative diseases are RBPs. Development of high-throughput sequencing methods has mapped out the fingerprints of RBPs on transcripts and provides unprecedented potential to discover new mechanisms of neurological diseases. Insights into how RBPs modulate neural development are important for designing effective therapies for numerous neurodevelopmental and neurodegenerative diseases. Summary RBPs have diverse mechanisms for modulating RNA processing and, thereby, controlling neurogenesis. Understanding the role of disease-associated RBPs in neurogenesis is vital for developing novel treatments for neurological diseases.
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Affiliation(s)
- Yijing Zhou
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Fengping Dong
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yingwei Mao
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
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20
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Bienkowski RS, Banerjee A, Rounds JC, Rha J, Omotade OF, Gross C, Morris KJ, Leung SW, Pak C, Jones SK, Santoro MR, Warren ST, Zheng JQ, Bassell GJ, Corbett AH, Moberg KH. The Conserved, Disease-Associated RNA Binding Protein dNab2 Interacts with the Fragile X Protein Ortholog in Drosophila Neurons. Cell Rep 2018; 20:1372-1384. [PMID: 28793261 DOI: 10.1016/j.celrep.2017.07.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/28/2017] [Accepted: 07/14/2017] [Indexed: 12/20/2022] Open
Abstract
The Drosophila dNab2 protein is an ortholog of human ZC3H14, a poly(A) RNA binding protein required for intellectual function. dNab2 supports memory and axon projection, but its molecular role in neurons is undefined. Here, we present a network of interactions that links dNab2 to cytoplasmic control of neuronal mRNAs in conjunction with the fragile X protein ortholog dFMRP. dNab2 and dfmr1 interact genetically in control of neurodevelopment and olfactory memory, and their encoded proteins co-localize in puncta within neuronal processes. dNab2 regulates CaMKII, but not futsch, implying a selective role in control of dFMRP-bound transcripts. Reciprocally, dFMRP and vertebrate FMRP restrict mRNA poly(A) tail length, similar to dNab2/ZC3H14. Parallel studies of murine hippocampal neurons indicate that ZC3H14 is also a cytoplasmic regulator of neuronal mRNAs. Altogether, these findings suggest that dNab2 represses expression of a subset of dFMRP-target mRNAs, which could underlie brain-specific defects in patients lacking ZC3H14.
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Affiliation(s)
- Rick S Bienkowski
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ayan Banerjee
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - J Christopher Rounds
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jennifer Rha
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Omotola F Omotade
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Christina Gross
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Kevin J Morris
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Sara W Leung
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - ChangHui Pak
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Stephanie K Jones
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Michael R Santoro
- Department of Human Genetics, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Stephen T Warren
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Human Genetics, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Pediatrics, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - James Q Zheng
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Kenneth H Moberg
- Department of Cell Biology, Emory University and Emory University School of Medicine, Atlanta, GA 30322, USA.
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21
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Neuronal RNP granules: from physiological to pathological assemblies. Biol Chem 2018; 399:623-635. [DOI: 10.1515/hsz-2018-0141] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Abstract
Neuronal cells rely on macro- and micro-cellular compartmentalization to rapidly process information, and respond locally to external stimuli. Such a cellular organization is achieved via the assembly of neuronal ribonucleoprotein (RNP) granules, dynamic membrane-less organelles enriched in RNAs and associated regulatory proteins. In this review, we discuss how these high-order structures transport mRNAs to dendrites and axons, and how they contribute to the spatio-temporal regulation of localized mRNA translation. We also highlight how recent biophysical studies have shed light on the mechanisms underlying neuronal RNP granule dynamic assembly, remodeling and maturation, in both physiological and pathological contexts.
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22
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Abstract
Spinal muscular atrophy (SMA) is a motor neuron disease caused by mutations/deletions within the survival of motor neuron 1 (SMN1) gene that lead to a pathological reduction of SMN protein levels. SMN is part of a multiprotein complex, functioning as a molecular chaperone that facilitates the assembly of spliceosomal small nuclear ribonucleoproteins (snRNP). In addition to its role in spliceosome formation, SMN has also been found to interact with mRNA-binding proteins (mRBPs), and facilitate their assembly into mRNP transport granules. The association of protein and RNA in RNP complexes plays an important role in an extensive and diverse set of cellular processes that regulate neuronal growth, differentiation, and the maturation and plasticity of synapses. This review discusses the role of SMN in RNP assembly and localization, focusing on molecular defects that affect mRNA processing and may contribute to SMA pathology.
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23
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Nutter CA, Kuyumcu-Martinez MN. Emerging roles of RNA-binding proteins in diabetes and their therapeutic potential in diabetic complications. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 9. [PMID: 29280295 DOI: 10.1002/wrna.1459] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/19/2017] [Accepted: 11/05/2017] [Indexed: 12/11/2022]
Abstract
Diabetes is a debilitating health care problem affecting 422 million people around the world. Diabetic patients suffer from multisystemic complications that can cause mortality and morbidity. Recent advancements in high-throughput next-generation RNA-sequencing and computational algorithms led to the discovery of aberrant posttranscriptional gene regulatory programs in diabetes. However, very little is known about how these regulatory programs are mis-regulated in diabetes. RNA-binding proteins (RBPs) are important regulators of posttranscriptional RNA networks, which are also dysregulated in diabetes. Human genetic studies provide new evidence that polymorphisms and mutations in RBPs are linked to diabetes. Therefore, we will discuss the emerging roles of RBPs in abnormal posttranscriptional gene expression in diabetes. Questions that will be addressed are: Which posttranscriptional mechanisms are disrupted in diabetes? Which RBPs are responsible for such changes under diabetic conditions? How are RBPs altered in diabetes? How does dysregulation of RBPs contribute to diabetes? Can we target RBPs using RNA-based methods to restore gene expression profiles in diabetic patients? Studying the evolving roles of RBPs in diabetes is critical not only for a comprehensive understanding of diabetes pathogenesis but also to design RNA-based therapeutic approaches for diabetic complications. WIREs RNA 2018, 9:e1459. doi: 10.1002/wrna.1459 This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing Translation > Translation Regulation.
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Affiliation(s)
- Curtis A Nutter
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas
| | - Muge N Kuyumcu-Martinez
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas.,Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas.,Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas
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24
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Terenzio M, Schiavo G, Fainzilber M. Compartmentalized Signaling in Neurons: From Cell Biology to Neuroscience. Neuron 2017; 96:667-679. [PMID: 29096079 DOI: 10.1016/j.neuron.2017.10.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/27/2017] [Accepted: 10/09/2017] [Indexed: 12/18/2022]
Abstract
Neurons are the largest known cells, with complex and highly polarized morphologies. As such, neuronal signaling is highly compartmentalized, requiring sophisticated transfer mechanisms to convey and integrate information within and between sub-neuronal compartments. Here, we survey different modes of compartmentalized signaling in neurons, highlighting examples wherein the fundamental cell biological processes of protein synthesis and degradation, membrane trafficking, and organelle transport are employed to enable the encoding and integration of information, locally and globally within a neuron. Comparisons to other cell types indicate that neurons accentuate widely shared mechanisms, providing invaluable models for the compartmentalization and transfer mechanisms required and used by most eukaryotic cells.
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Affiliation(s)
- Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, UK; Discoveries Centre for Regenerative and Precision Medicine at UCL, London WC1N 3BG, UK; UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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