101
|
Ivanov P, Kedersha N, Anderson P. Stress Granules and Processing Bodies in Translational Control. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032813. [PMID: 30082464 DOI: 10.1101/cshperspect.a032813] [Citation(s) in RCA: 280] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Stress granules (SGs) and processing bodies (PBs) are non-membrane-enclosed RNA granules that dynamically sequester translationally inactive messenger ribonucleoprotein particles (mRNPs) into compartments that are distinct from the surrounding cytoplasm. mRNP remodeling, silencing, and/or storage involves the dynamic partitioning of closed-loop polyadenylated mRNPs into SGs, or the sequestration of deadenylated, linear mRNPs into PBs. SGs form when stress-activated pathways stall translation initiation but allow elongation and termination to occur normally, resulting in a sudden excess of mRNPs that are spatially condensed into discrete foci by protein:protein, protein:RNA, and RNA:RNA interactions. In contrast, PBs can exist in the absence of stress, when specific factors promote mRNA deadenylation, condensation, and sequestration from the translational machinery. The formation and dissolution of SGs and PBs reflect changes in messenger RNA (mRNA) metabolism and allow cells to modulate the proteome and/or mediate life or death decisions during changing environmental conditions.
Collapse
Affiliation(s)
- Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts 02115.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115.,The Broad Institute of Harvard and M.I.T., Cambridge, Massachusetts 02142
| | - Nancy Kedersha
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts 02115.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
| | - Paul Anderson
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts 02115.,Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115
| |
Collapse
|
102
|
Pal R, Bhattacharya A. Modelling Protein Synthesis as A Biomarker in Fragile X Syndrome Patient-Derived Cells. Brain Sci 2019; 9:E59. [PMID: 30862080 PMCID: PMC6468675 DOI: 10.3390/brainsci9030059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/27/2019] [Accepted: 03/06/2019] [Indexed: 12/26/2022] Open
Abstract
The most conserved molecular phenotype of Fragile X Syndrome (FXS) is aberrant protein synthesis. This has been validated in a variety of experimental model systems from zebrafish to rats, patient-derived lymphoblasts and fibroblasts. With the advent of personalized medicine paradigms, patient-derived cells and their derivatives are gaining more translational importance, not only to model disease in a dish, but also for biomarker discovery. Here we review past and current practices of measuring protein synthesis in FXS, studies in patient derived cells and the inherent challenges in measuring protein synthesis in them to offer usable avenues of modeling this important metabolic metric for further biomarker development.
Collapse
Affiliation(s)
- Rakhi Pal
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bellary Road, Bengaluru 560065, India.
| | - Aditi Bhattacharya
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, GKVK Post, Bellary Road, Bengaluru 560065, India.
| |
Collapse
|
103
|
Phosphoregulated FMRP phase separation models activity-dependent translation through bidirectional control of mRNA granule formation. Proc Natl Acad Sci U S A 2019; 116:4218-4227. [PMID: 30765518 DOI: 10.1073/pnas.1814385116] [Citation(s) in RCA: 215] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Activity-dependent translation requires the transport of mRNAs within membraneless protein assemblies known as neuronal granules from the cell body toward synaptic regions. Translation of mRNA is inhibited in these granules during transport but quickly activated in response to neuronal stimuli at the synapse. This raises an important question: how does synaptic activity trigger translation of once-silenced mRNAs? Here, we demonstrate a strong connection between phase separation, the process underlying the formation of many different types of cellular granules, and in vitro inhibition of translation. By using the Fragile X Mental Retardation Protein (FMRP), an abundant neuronal granule component and translational repressor, we show that FMRP phase separates in vitro with RNA into liquid droplets mediated by its C-terminal low-complexity disordered region (i.e., FMRPLCR). FMRPLCR posttranslational modifications by phosphorylation and methylation have opposing effects on in vitro translational regulation, which corroborates well with their critical concentrations for phase separation. Our results, combined with bioinformatics evidence, are supportive of phase separation as a general mechanism controlling activity-dependent translation.
Collapse
|
104
|
Maurin T, Bardoni B. Fragile X Mental Retardation Protein: To Be or Not to Be a Translational Enhancer. Front Mol Biosci 2018; 5:113. [PMID: 30619879 PMCID: PMC6297276 DOI: 10.3389/fmolb.2018.00113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/26/2018] [Indexed: 12/18/2022] Open
Affiliation(s)
- Thomas Maurin
- Université Côte d'Azur, CNRS UMR7275, Institute of Molecular and Cellular Pharmacology, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | - Barbara Bardoni
- CNRS LIA "Neogenex", Valbonne, France.,Université Côte d'Azur, INSERM, CNRS UMR7275, Institute of Molecular and Cellular Pharmacology, Valbonne, France
| |
Collapse
|
105
|
Soto-Acosta R, Xie X, Shan C, Baker CK, Shi PY, Rossi SL, Garcia-Blanco MA, Bradrick S. Fragile X mental retardation protein is a Zika virus restriction factor that is antagonized by subgenomic flaviviral RNA. eLife 2018; 7:39023. [PMID: 30511641 PMCID: PMC6279352 DOI: 10.7554/elife.39023] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/12/2018] [Indexed: 12/19/2022] Open
Abstract
Subgenomic flaviviral RNA (sfRNA) accumulates during infection due to incomplete degradation of viral genomes and interacts with cellular proteins to promote infection. Here we identify host proteins that bind the Zika virus (ZIKV) sfRNA. We identified fragile X mental retardation protein (FMRP) as a ZIKV sfRNA-binding protein and confirmed this interaction in cultured cells and mouse testes. Depletion of FMRP elevated viral translation and enhanced ZIKV infection, indicating that FMRP is a ZIKV restriction factor. We further observed that an attenuated ZIKV strain compromised for sfRNA production was disproportionately stimulated by FMRP knockdown, suggesting that ZIKV sfRNA antagonizes FMRP activity. Importantly, ZIKV infection and expression of ZIKV sfRNA upregulated endogenous FMRP target genes in cell culture and ZIKV-infected mice. Together, our observations identify FMRP as a ZIKV restriction factor whose activity is antagonized by the sfRNA. Interaction between ZIKV and FMRP has significant implications for the pathogenesis of ZIKV infections.
Collapse
Affiliation(s)
- Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Xuping Xie
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Chao Shan
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States
| | - Coleman K Baker
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, United States.,Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, United States.,Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States
| | - Shannan L Rossi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Department of Pathology, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Shelton Bradrick
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, United States.,Institute for Human Infections & Immunity, University of Texas Medical Branch, Galveston, United States.,Center for Biodefense & Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, United States
| |
Collapse
|
106
|
D'Souza MN, Gowda NKC, Tiwari V, Babu RO, Anand P, Dastidar SG, Singh R, James OG, Selvaraj B, Pal R, Ramesh A, Chattarji S, Chandran S, Gulyani A, Palakodeti D, Muddashetty RS. FMRP Interacts with C/D Box snoRNA in the Nucleus and Regulates Ribosomal RNA Methylation. iScience 2018; 9:399-411. [PMID: 30469012 PMCID: PMC6249352 DOI: 10.1016/j.isci.2018.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 09/28/2018] [Accepted: 11/01/2018] [Indexed: 12/19/2022] Open
Abstract
FMRP is an RNA-binding protein that is known to localize in the cytoplasm and in the nucleus. Here, we have identified an interaction of FMRP with a specific set of C/D box snoRNAs in the nucleus. C/D box snoRNAs guide 2’O methylations of ribosomal RNA (rRNA) on defined sites, and this modification regulates rRNA folding and assembly of ribosomes. 2’O methylation of rRNA is partial on several sites in human embryonic stem cells, which results in ribosomes with differential methylation patterns. FMRP-snoRNA interaction affects rRNA methylation on several of these sites, and in the absence of FMRP, differential methylation pattern of rRNA is significantly altered. We found that FMRP recognizes ribosomes carrying specific methylation patterns on rRNA and the recognition of methylation pattern by FMRP may potentially determine the translation status of its target mRNAs. Thus, FMRP integrates its function in the nucleus and in the cytoplasm. FMRP binds to C/D Box snoRNAs in the nucleus Differential 2’O-methylation on rRNA contributes to ribosome heterogeneity in a cell 2’O-Methylation pattern on ribosomal RNA is altered in the absence of FMRP FMRP recognizes 2’O-methylation on rRNA, which may determine interaction with ribosomes
Collapse
Affiliation(s)
- Michelle Ninochka D'Souza
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India; The University of Trans-Disciplinary Health Sciences & Technology (TDU), Bengaluru, Karnataka 560064, India
| | | | - Vishal Tiwari
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India; National Centre for Biological Sciences, Bengaluru, Karnataka 560065, India
| | | | - Praveen Anand
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India
| | - Sudhriti Ghosh Dastidar
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India; Manipal Academy of Higher Education, Madhav Nagar, Manipal, Karnataka 576104, India
| | - Randhir Singh
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India
| | - Owen G James
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Bhuvaneish Selvaraj
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Rakhi Pal
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India
| | - Arati Ramesh
- National Centre for Biological Sciences, Bengaluru, Karnataka 560065, India
| | - Sumantra Chattarji
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India; National Centre for Biological Sciences, Bengaluru, Karnataka 560065, India; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Siddharthan Chandran
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India; Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK; UK Dementia Research Institute at Edinburgh, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Akash Gulyani
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India
| | - Ravi S Muddashetty
- Institute for Stem Cell Biology and Regenerative Medicine, Bengaluru 560065, India.
| |
Collapse
|
107
|
Impaired GABA Neural Circuits Are Critical for Fragile X Syndrome. Neural Plast 2018; 2018:8423420. [PMID: 30402088 PMCID: PMC6192167 DOI: 10.1155/2018/8423420] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/17/2018] [Indexed: 12/24/2022] Open
Abstract
Fragile X syndrome (FXS) is an inheritable neuropsychological disease caused by silence of the fmr1 gene and the deficiency of Fragile X mental retardation protein (FMRP). Patients present neuronal alterations that lead to severe intellectual disability and altered sleep rhythms. However, the neural circuit mechanisms underlying FXS remain unclear. Previous studies have suggested that metabolic glutamate and gamma-aminobutyric acid (GABA) receptors/circuits are two counter-balanced factors involved in FXS pathophysiology. More and more studies demonstrated that attenuated GABAergic circuits in the absence of FMRP are critical for abnormal progression of FXS. Here, we reviewed the changes of GABA neural circuits that were attributed to intellectual-deficient FXS, from several aspects including deregulated GABA metabolism, decreased expressions of GABA receptor subunits, and impaired GABAergic neural circuits. Furthermore, the activities of GABA neural circuits are modulated by circadian rhythm of FMRP metabolism and reviewed the abnormal condition of FXS mice or patients.
Collapse
|
108
|
Haenfler JM, Skariah G, Rodriguez CM, Monteiro da Rocha A, Parent JM, Smith GD, Todd PK. Targeted Reactivation of FMR1 Transcription in Fragile X Syndrome Embryonic Stem Cells. Front Mol Neurosci 2018; 11:282. [PMID: 30158855 PMCID: PMC6104480 DOI: 10.3389/fnmol.2018.00282] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/25/2018] [Indexed: 12/15/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited cause of intellectual disability and autism. It results from expansion of a CGG nucleotide repeat in the 5′ untranslated region (UTR) of FMR1. Large expansions elicit repeat and promoter hyper-methylation, heterochromatin formation, FMR1 transcriptional silencing and loss of the Fragile X protein, FMRP. Efforts aimed at correcting the sequelae resultant from FMRP loss have thus far proven insufficient, perhaps because of FMRP’s pleiotropic functions. As the repeats do not disrupt the FMRP coding sequence, reactivation of endogenous FMR1 gene expression could correct the proximal event in FXS pathogenesis. Here we utilize the Clustered Regularly Interspaced Palindromic Repeats/deficient CRISPR associated protein 9 (CRISPR/dCas9) system to selectively re-activate transcription from the silenced FMR1 locus. Fusion of the transcriptional activator VP192 to dCas9 robustly enhances FMR1 transcription and increases FMRP levels when targeted directly to the CGG repeat in human cells. Using a previously uncharacterized FXS human embryonic stem cell (hESC) line which acquires transcriptional silencing with serial passaging, we achieved locus-specific transcriptional re-activation of FMR1 messenger RNA (mRNA) expression despite promoter and repeat methylation. However, these changes at the transcript level were not coupled with a significant elevation in FMRP protein expression in FXS cells. These studies demonstrate that directing a transcriptional activator to CGG repeats is sufficient to selectively reactivate FMR1 mRNA expression in Fragile X patient stem cells.
Collapse
Affiliation(s)
- Jill M Haenfler
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Andre Monteiro da Rocha
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, United States
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
| | - Gary D Smith
- Departments of Obstetrics/Gynecology, Physiology, and Urology, University of Michigan, Ann Arbor, MI, United States
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
| |
Collapse
|
109
|
Ferro D, Yao S, Zarnescu DC. Dynamic duo - FMRP and TDP-43: Regulating common targets, causing different diseases. Brain Res 2018; 1693:37-42. [PMID: 29715444 PMCID: PMC5997554 DOI: 10.1016/j.brainres.2018.04.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 10/17/2022]
Abstract
RNA binding proteins play essential roles during development and aging, and are also involved in disease pathomechanisms. RNA sequencing and omics analyses have provided a window into systems level alterations in neurological disease, and have identified RNA processing defects among notable disease mechanisms. This review focuses on two seemingly distinct neurological disorders, the RNA binding proteins they are linked to, and their newly discovered functional relationship. When deficient, Fragile X Mental Retardation Protein (FMRP) causes developmental deficits and autistic behaviors while TAR-DNA Binding Protein (TDP-43) dysregulation causes age dependent neuronal degeneration. Recent findings that FMRP and TDP-43 associate in ribonuclear protein particles and share mRNA targets in neurons highlight the critical importance of translation regulation in synaptic plasticity and provide new perspectives on neuronal vulnerability during lifespan.
Collapse
Affiliation(s)
- Diana Ferro
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
| | - Stephen Yao
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
| | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States; Department of Neuroscience, University of Arizona, Tucson, AZ, United States; Department of Neurology, University of Arizona, Tucson AZ, United States.
| |
Collapse
|
110
|
Ravanidis S, Kattan FG, Doxakis E. Unraveling the Pathways to Neuronal Homeostasis and Disease: Mechanistic Insights into the Role of RNA-Binding Proteins and Associated Factors. Int J Mol Sci 2018; 19:ijms19082280. [PMID: 30081499 PMCID: PMC6121432 DOI: 10.3390/ijms19082280] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The timing, dosage and location of gene expression are fundamental determinants of brain architectural complexity. In neurons, this is, primarily, achieved by specific sets of trans-acting RNA-binding proteins (RBPs) and their associated factors that bind to specific cis elements throughout the RNA sequence to regulate splicing, polyadenylation, stability, transport and localized translation at both axons and dendrites. Not surprisingly, misregulation of RBP expression or disruption of its function due to mutations or sequestration into nuclear or cytoplasmic inclusions have been linked to the pathogenesis of several neuropsychiatric and neurodegenerative disorders such as fragile-X syndrome, autism spectrum disorders, spinal muscular atrophy, amyotrophic lateral sclerosis and frontotemporal dementia. This review discusses the roles of Pumilio, Staufen, IGF2BP, FMRP, Sam68, CPEB, NOVA, ELAVL, SMN, TDP43, FUS, TAF15, and TIA1/TIAR in RNA metabolism by analyzing their specific molecular and cellular function, the neurological symptoms associated with their perturbation, and their axodendritic transport/localization along with their target mRNAs as part of larger macromolecular complexes termed ribonucleoprotein (RNP) granules.
Collapse
Affiliation(s)
- Stylianos Ravanidis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Fedon-Giasin Kattan
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Epaminondas Doxakis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| |
Collapse
|
111
|
Genuth NR, Barna M. The Discovery of Ribosome Heterogeneity and Its Implications for Gene Regulation and Organismal Life. Mol Cell 2018; 71:364-374. [PMID: 30075139 DOI: 10.1016/j.molcel.2018.07.018get] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/08/2018] [Accepted: 07/16/2018] [Indexed: 05/27/2023]
Abstract
The ribosome has recently transitioned from being viewed as a passive, indiscriminate machine to a more dynamic macromolecular complex with specialized roles in the cell. Here, we discuss the historical milestones from the discovery of the ribosome itself to how this ancient machinery has gained newfound appreciation as a more regulatory participant in the central dogma of gene expression. The first emerging examples of direct changes in ribosome composition at the RNA and protein level, coupled with an increased awareness of the role individual ribosomal components play in the translation of specific mRNAs, is opening a new field of study centered on ribosome-mediated control of gene regulation. In this Perspective, we discuss our current understanding of the known functions for ribosome heterogeneity, including specialized translation of individual transcripts, and its implications for the regulation and expression of key gene regulatory networks. In addition, we suggest what the crucial next steps are to ascertain the extent of ribosome heterogeneity and specialization and its importance for regulation of the proteome within subcellular space, across different cell types, and during multi-cellular organismal development.
Collapse
Affiliation(s)
- Naomi R Genuth
- Department of Developmental Biology, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA; Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA.
| |
Collapse
|
112
|
Genuth NR, Barna M. The Discovery of Ribosome Heterogeneity and Its Implications for Gene Regulation and Organismal Life. Mol Cell 2018; 71:364-374. [PMID: 30075139 PMCID: PMC6092941 DOI: 10.1016/j.molcel.2018.07.018] [Citation(s) in RCA: 269] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/08/2018] [Accepted: 07/16/2018] [Indexed: 12/24/2022]
Abstract
The ribosome has recently transitioned from being viewed as a passive, indiscriminate machine to a more dynamic macromolecular complex with specialized roles in the cell. Here, we discuss the historical milestones from the discovery of the ribosome itself to how this ancient machinery has gained newfound appreciation as a more regulatory participant in the central dogma of gene expression. The first emerging examples of direct changes in ribosome composition at the RNA and protein level, coupled with an increased awareness of the role individual ribosomal components play in the translation of specific mRNAs, is opening a new field of study centered on ribosome-mediated control of gene regulation. In this Perspective, we discuss our current understanding of the known functions for ribosome heterogeneity, including specialized translation of individual transcripts, and its implications for the regulation and expression of key gene regulatory networks. In addition, we suggest what the crucial next steps are to ascertain the extent of ribosome heterogeneity and specialization and its importance for regulation of the proteome within subcellular space, across different cell types, and during multi-cellular organismal development.
Collapse
Affiliation(s)
- Naomi R Genuth
- Department of Developmental Biology, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA; Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, CA, 94305, USA; Department of Genetics, Stanford University, Stanford, CA, 94305, USA.
| |
Collapse
|
113
|
Specialized ribosomes and the control of translation. Biochem Soc Trans 2018; 46:855-869. [PMID: 29986937 DOI: 10.1042/bst20160426] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 05/21/2018] [Accepted: 05/24/2018] [Indexed: 11/17/2022]
Abstract
The control of translation is increasingly recognized as a major factor in determining protein levels in the cell. The ribosome - the cellular machine that mediates protein synthesis - is typically seen as a key, but invariant, player in this process. This is because translational control is thought to be mediated by other auxiliary factors while ribosome recruitment is seen as the end-point of regulation. However, recent developments have made it clear that heterogeneous ribosome types can exist in different tissues, and more importantly, that these ribosomes can preferentially translate different subsets of mRNAs. In so doing, heterogeneous ribosomes could be key regulatory players in differentiation and development. Here, we examine current evidence for the existence of different ribosome types and how they might arise. In particular, we will take a close look at the mechanisms through which these ribosomes might mediate selective mRNA translation. We also summarize recently developed techniques/approaches that will aid in our understanding of the functions of such specialized ribosomes.
Collapse
|
114
|
Blair JD, Hockemeyer D, Doudna JA, Bateup HS, Floor SN. Widespread Translational Remodeling during Human Neuronal Differentiation. Cell Rep 2018; 21:2005-2016. [PMID: 29141229 DOI: 10.1016/j.celrep.2017.10.095] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/13/2017] [Accepted: 10/24/2017] [Indexed: 01/04/2023] Open
Abstract
Faithful cellular differentiation requires temporally precise activation of gene expression programs, which are coordinated at the transcriptional and translational levels. Neurons express the most complex set of mRNAs of any human tissue, but translational changes during neuronal differentiation remain incompletely understood. Here, we induced forebrain neuronal differentiation of human embryonic stem cells (hESCs) and measured genome-wide RNA and translation levels with transcript-isoform resolution. We found that thousands of genes change translation status during differentiation without a corresponding change in RNA level. Specifically, we identified mTOR signaling as a key driver for elevated translation of translation-related genes in hESCs. In contrast, translational repression in active neurons is mediated by regulatory sequences in 3' UTRs. Together, our findings identify extensive translational control changes during human neuronal differentiation and a crucial role of 3' UTRs in driving cell-type-specific translation.
Collapse
Affiliation(s)
- John D Blair
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Jennifer A Doudna
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Molecular Biophysics and Imaging Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Helen S Bateup
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Stephen N Floor
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
| |
Collapse
|
115
|
Gallagher C, Ramos A. Joining the dots - protein-RNA interactions mediating local mRNA translation in neurons. FEBS Lett 2018; 592:2932-2947. [PMID: 29856909 DOI: 10.1002/1873-3468.13121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/24/2018] [Accepted: 05/30/2018] [Indexed: 01/26/2023]
Abstract
Establishing and maintaining the complex network of connections required for neuronal communication requires the transport and in situ translation of large groups of mRNAs to create local proteomes. In this Review, we discuss the regulation of local mRNA translation in neurons and the RNA-binding proteins that recognise RNA zipcode elements and connect the mRNAs to the cellular transport networks, as well as regulate their translation control. However, mRNA recognition by the regulatory proteins is mediated by the combinatorial action of multiple RNA-binding domains. This increases the specificity and affinity of the interaction, while allowing the protein to recognise a diverse set of targets and mediate a range of mechanisms for translational regulation. The structural and molecular understanding of the interactions can be used together with novel microscopy and transcriptome-wide data to build a mechanistic framework for the regulation of local mRNA translation.
Collapse
Affiliation(s)
- Christopher Gallagher
- Institute of Structural and Molecular Biology, University College London, UK.,The Francis Crick Institute, London, UK
| | - Andres Ramos
- Institute of Structural and Molecular Biology, University College London, UK
| |
Collapse
|
116
|
Arias-Mireles BH, de Rozieres CM, Ly K, Joseph S. RNA Modulates the Interaction between Influenza A Virus NS1 and Human PABP1. Biochemistry 2018; 57:3590-3598. [PMID: 29782795 DOI: 10.1021/acs.biochem.8b00218] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nonstructural protein 1 (NS1) is a multifunctional protein involved in preventing host-interferon response in influenza A virus (IAV). Previous studies have indicated that NS1 also stimulates the translation of viral mRNA by binding to conserved sequences in the viral 5'-UTR. Additionally, NS1 binds to poly(A) binding protein 1 (PABP1) and eukaryotic initiation factor 4G (eIF4G). The interaction of NS1 with the viral 5'-UTR, PABP1, and eIF4G has been suggested to specifically enhance the translation of viral mRNAs. In contrast, we report that NS1 does not directly bind to sequences in the viral 5'-UTR, indicating that NS1 is not responsible for providing the specificity to stimulate viral mRNA translation. We also monitored the interaction of NS1 with PABP1 using a new, quantitative FRET assay. Our data show that NS1 binds to PABP1 with high affinity; however, the binding of double-stranded RNA (dsRNA) to NS1 weakens the binding of NS1 to PABP1. Correspondingly, the binding of PABP1 to NS1 weakens the binding of NS1 to double-stranded RNA (dsRNA). In contrast, the affinity of PABP1 for binding to poly(A) RNA is not significantly changed by NS1. We propose that the modulation of NS1·PABP1 interaction by dsRNA may be important for the viral cycle.
Collapse
Affiliation(s)
- Bryan H Arias-Mireles
- Department of Biological Sciences , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093 , United States
| | - Cyrus M de Rozieres
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093 , United States
| | - Kevin Ly
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093 , United States
| | - Simpson Joseph
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093 , United States
| |
Collapse
|
117
|
Leppek K, Das R, Barna M. Functional 5' UTR mRNA structures in eukaryotic translation regulation and how to find them. Nat Rev Mol Cell Biol 2018; 19:158-174. [PMID: 29165424 PMCID: PMC5820134 DOI: 10.1038/nrm.2017.103] [Citation(s) in RCA: 504] [Impact Index Per Article: 84.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RNA molecules can fold into intricate shapes that can provide an additional layer of control of gene expression beyond that of their sequence. In this Review, we discuss the current mechanistic understanding of structures in 5' untranslated regions (UTRs) of eukaryotic mRNAs and the emerging methodologies used to explore them. These structures may regulate cap-dependent translation initiation through helicase-mediated remodelling of RNA structures and higher-order RNA interactions, as well as cap-independent translation initiation through internal ribosome entry sites (IRESs), mRNA modifications and other specialized translation pathways. We discuss known 5' UTR RNA structures and how new structure probing technologies coupled with prospective validation, particularly compensatory mutagenesis, are likely to identify classes of structured RNA elements that shape post-transcriptional control of gene expression and the development of multicellular organisms.
Collapse
Affiliation(s)
- Kathrin Leppek
- Department of Developmental Biology, Stanford University, Stanford, California 94305, USA
- Department of Genetics, Stanford University, Stanford, California 94305, USA
| | - Rhiju Das
- Departments of Biochemistry and Physics, Stanford University, Stanford, California 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, California 94305, USA
- Department of Genetics, Stanford University, Stanford, California 94305, USA
| |
Collapse
|
118
|
|
119
|
Abstract
Post-transcriptional regulation is linked to the development of pain hypersensitivity. A growing body of evidence indicates that RNA-binding proteins are involved in pain. RNA-based inhibitors are a potential new source of pain therapeutics.
RNA-protein interactions permeate biology. Transcription, translation, processing, and mRNA decay all hinge on widespread use of regulatory information decoded by RNA-binding proteins. The final committed step of protein synthesis, translation, is intimately linked to nociceptor excitability. Understanding the factors that control translation is essential as nociceptor plasticity is a hallmark of persistent pain. Here, we review the growing body of evidence for widespread involvement of RNA-binding proteins in pain. Many of the relevant factors have been implicated in post-transcriptional and translational mechanisms of mRNA control. We propose that recent advances in the development of RNA-based therapeutics provide a potential means to exploit our current understanding of liaisons between RNAs and proteins for therapeutic purposes.
Collapse
Affiliation(s)
| | - Zachary T. Campbell
- Corresponding author at: Department of Biological Sciences, 800 W. Campbell Road, RL10 BSB 12.510, Richardson, TX 75080, United States.
| |
Collapse
|
120
|
Lehmkuhl EM, Zarnescu DC. Lost in Translation: Evidence for Protein Synthesis Deficits in ALS/FTD and Related Neurodegenerative Diseases. ADVANCES IN NEUROBIOLOGY 2018; 20:283-301. [PMID: 29916024 DOI: 10.1007/978-3-319-89689-2_11] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cells utilize a complex network of proteins to regulate translation, involving post-transcriptional processing of RNA and assembly of the ribosomal unit. Although the complexity provides robust regulation of proteostasis, it also offers several opportunities for translational dysregulation, as has been observed in many neurodegenerative disorders. Defective mRNA localization, mRNA sequatration, inhibited ribogenesis, mutant tRNA synthetases, and translation of hexanucleotide expansions have all been associated with neurodegenerative disease. Here, we review dysregulation of translation in the context of age-related neurodegeneration and discuss novel methods to interrogate translation. This review primarily focuses on amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), a spectrum disorder heavily associated with RNA metabolism, while also analyzing translational inhibition in the context of related neurodegenerative disorders such as Alzheimer's disease and Huntington's disease and the translation-related pathomechanisms common in neurodegenerative disease.
Collapse
Affiliation(s)
- Erik M Lehmkuhl
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA. .,Department of Neuroscience, University of Arizona, Tucson, AZ, USA. .,Department of Neurology, University of Arizona, Tucson, AZ, USA.
| |
Collapse
|
121
|
Dynamic landscape of the local translation at activated synapses. Mol Psychiatry 2018; 23:107-114. [PMID: 29203851 PMCID: PMC5754473 DOI: 10.1038/mp.2017.245] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 10/09/2017] [Indexed: 01/17/2023]
Abstract
The mammalian target of rapamycin (mTOR) signaling pathway is the central regulator of cap-dependent translation at the synapse. Disturbances in mTOR pathway have been associated with several neurological diseases, such as autism and epilepsy. RNA-binding protein FMRP, a negative regulator of translation initiation, is one of the key components of the local translation system. Activation and inactivation of FMRP occurs via phosphorylation by S6 kinase and dephosphorylation by PP2A phosphatase, respectively. S6 kinase and PP2A phosphatase are activated in response to mGluR receptor stimulation through different signaling pathways and at different rates. The dynamic aspects of this system are poorly understood. We developed a mathematical model of FMRP-dependent regulation of postsynaptic density (PSD) protein synthesis in response to mGluR receptor stimulation and conducted in silico experiments to study the regulatory circuit functioning. The modeling results revealed the possibility of generating oscillatory (cyclic and quasi-cyclic), chaotic and even hyperchaotic dynamics of postsynaptic protein synthesis as well as the presence of multiple attractors in a wide range of parameters of the local translation system. The results suggest that autistic disorders associated with mTOR pathway hyperactivation may be due to impaired proteome stability associated with the formation of complex dynamic regimes of PSD protein synthesis in response to stimulation of mGluR receptors on the postsynaptic membrane of excitatory synapses on pyramidal hippocampal cells.
Collapse
|
122
|
Xu B, Zhang Y, Zhan S, Wang X, Zhang H, Meng X, Ge W. Proteomic Profiling of Brain and Testis Reveals the Diverse Changes in Ribosomal Proteins in fmr1 Knockout Mice. Neuroscience 2017; 371:469-483. [PMID: 29292077 DOI: 10.1016/j.neuroscience.2017.12.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS), the leading cause of inherited forms of mental retardation and autism, is caused by the transcriptional silencing of fmr1 encoding the fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein that is a widely expressed, but primarily in the brain and testis, and associated approximately 4% of transcripts. Macro-orchidism is a common symptom associated with FXS both in humans and mice. Thus, we analyze the pooled samples of cerebral cortex, hippocampus and testis from both the fmr1-KO and wild-type mice by a LC-MS/MS proteomic study. Among the identified proteins, most of those showing significant changes in expression were up- or downregulated in the absence of FMRP. Proteins (FMRP, RPS8, RPL23a and ATPIF1, RPL6, GAP43, MTCH2 and MPZ in brain, and FMRP, CAH3, AKR1B7 and C9 in testis) identified by MS/MS were also verified by Western blotting. The Gene Ontology and WikiPathways analysis revealed that the differentially expressed proteins were clustered in the polyribosome and RNA-binding protein categories in both cerebral cortex and hippocampus, but not in testis. Although this study was limited by the little number of samples, our results provide detailed insights into the ribosomal protein profiles of cerebral cortex, hippocampus and testis in the absence of FMRP. Our studies also provide a better understanding of protein profile changes and the underlying dysregulated pathways arising from fmr1 silencing in FXS.
Collapse
Affiliation(s)
- Benhong Xu
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China; State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China; Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Yusheng Zhang
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Shaohua Zhan
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Xia Wang
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China
| | - Haisong Zhang
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China
| | - Xianbin Meng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Ge
- Affiliated Hospital of Hebei University, No. 212, Yu Hua East Road, Nan Shi District, Baoding, Hebei 071000, China; State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, No. 5 Dongdansantiao, Dongcheng District, Beijing 100005, China.
| |
Collapse
|
123
|
Arguello AE, DeLiberto AN, Kleiner RE. RNA Chemical Proteomics Reveals the N 6-Methyladenosine (m 6A)-Regulated Protein-RNA Interactome. J Am Chem Soc 2017; 139:17249-17252. [PMID: 29140688 DOI: 10.1021/jacs.7b09213] [Citation(s) in RCA: 199] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Epitranscriptomic RNA modifications can regulate mRNA function; however, there is a major gap in our understanding of the biochemical mechanisms mediating their effects. Here, we develop a chemical proteomics approach relying upon photo-cross-linking with synthetic diazirine-containing RNA probes and quantitative proteomics to profile RNA-protein interactions regulated by N6-methyladenosine (m6A), the most abundant internal modification in eukaryotic RNA. In addition to identifying YTH domain-containing proteins and ALKBH5, known interactors of this modification, we find that FMR1 and LRPPRC, two proteins associated with human disease, "read" this modification. Surprisingly, we also find that m6A disrupts RNA binding by the stress granule proteins G3BP1/2, USP10, CAPRIN1, and RBM42. Our work provides a general strategy for interrogating the interactome of RNA modifications and reveals the biochemical mechanisms underlying m6A function in the cell.
Collapse
Affiliation(s)
- A Emilia Arguello
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Amanda N DeLiberto
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Ralph E Kleiner
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
124
|
Peuchen EH, Cox OF, Sun L, Hebert AS, Coon JJ, Champion MM, Dovichi NJ, Huber PW. Phosphorylation Dynamics Dominate the Regulated Proteome during Early Xenopus Development. Sci Rep 2017; 7:15647. [PMID: 29142207 PMCID: PMC5688136 DOI: 10.1038/s41598-017-15936-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/03/2017] [Indexed: 01/08/2023] Open
Abstract
The earliest stages of animal development are largely controlled by changes in protein phosphorylation mediated by signaling pathways and cyclin-dependent kinases. In order to decipher these complex networks and to discover new aspects of regulation by this post-translational modification, we undertook an analysis of the X. laevis phosphoproteome at seven developmental stages beginning with stage VI oocytes and ending with two-cell embryos. Concurrent measurement of the proteome and phosphoproteome enabled measurement of phosphosite occupancy as a function of developmental stage. We observed little change in protein expression levels during this period. We detected the expected phosphorylation of MAP kinases, translational regulatory proteins, and subunits of APC/C that validate the accuracy of our measurements. We find that more than half the identified proteins possess multiple sites of phosphorylation that are often clustered, where kinases work together in a hierarchical manner to create stretches of phosphorylated residues, which may be a means to amplify signals or stabilize a particular protein conformation. Conversely, other proteins have opposing sites of phosphorylation that seemingly reflect distinct changes in activity during this developmental timeline.
Collapse
Affiliation(s)
- Elizabeth H Peuchen
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Olivia F Cox
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Liangliang Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Alex S Hebert
- Department of Chemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Norman J Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Paul W Huber
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
| |
Collapse
|
125
|
McCullagh EA, Salcedo E, Huntsman MM, Klug A. Tonotopic alterations in inhibitory input to the medial nucleus of the trapezoid body in a mouse model of Fragile X syndrome. J Comp Neurol 2017; 525:3543-3562. [PMID: 28744893 PMCID: PMC5615817 DOI: 10.1002/cne.24290] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 12/19/2022]
Abstract
Hyperexcitability and the imbalance of excitation/inhibition are one of the leading causes of abnormal sensory processing in Fragile X syndrome (FXS). The precise timing and distribution of excitation and inhibition is crucial for auditory processing at the level of the auditory brainstem, which is responsible for sound localization ability. Sound localization is one of the sensory abilities disrupted by loss of the Fragile X Mental Retardation 1 (Fmr1) gene. Using triple immunofluorescence staining we tested whether there were alterations in the number and size of presynaptic structures for the three primary neurotransmitters (glutamate, glycine, and GABA) in the auditory brainstem of Fmr1 knockout mice. We found decreases in either glycinergic or GABAergic inhibition to the medial nucleus of the trapezoid body (MNTB) specific to the tonotopic location within the nucleus. MNTB is one of the primary inhibitory nuclei in the auditory brainstem and participates in the sound localization process with fast and well-timed inhibition. Thus, a decrease in inhibitory afferents to MNTB neurons should lead to greater inhibitory output to the projections from this nucleus. In contrast, we did not see any other significant alterations in balance of excitation/inhibition in any of the other auditory brainstem nuclei measured, suggesting that the alterations observed in the MNTB are both nucleus and frequency specific. We furthermore show that glycinergic inhibition may be an important contributor to imbalances in excitation and inhibition in FXS and that the auditory brainstem is a useful circuit for testing these imbalances.
Collapse
Affiliation(s)
- Elizabeth A McCullagh
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado
| | - Ernesto Salcedo
- Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
| | - Molly M Huntsman
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado
- Department of Pediatrics, School of Medicinen University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Achim Klug
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado
| |
Collapse
|
126
|
Ozdilek BA, Thompson VF, Ahmed NS, White CI, Batey RT, Schwartz JC. Intrinsically disordered RGG/RG domains mediate degenerate specificity in RNA binding. Nucleic Acids Res 2017; 45:7984-7996. [PMID: 28575444 PMCID: PMC5570134 DOI: 10.1093/nar/gkx460] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/25/2017] [Indexed: 12/13/2022] Open
Abstract
RGG/RG domains are the second most common RNA binding domain in the human genome, yet their RNA-binding properties remain poorly understood. Here, we report a detailed analysis of the RNA binding characteristics of intrinsically disordered RGG/RG domains from Fused in Sarcoma (FUS), FMRP and hnRNPU. For FUS, previous studies defined RNA binding as mediated by its well-folded domains; however, we show that RGG/RG domains are the primary mediators of binding. RGG/RG domains coupled to adjacent folded domains can achieve affinities approaching that of full-length FUS. Analysis of RGG/RG domains from FUS, FMRP and hnRNPU against a spectrum of contrasting RNAs reveals that each display degenerate binding specificity, while still displaying different degrees of preference for RNA.
Collapse
Affiliation(s)
- Bagdeser A Ozdilek
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Campus Box 347, Boulder, CO 80309, USA
| | - Valery F Thompson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Nasiha S Ahmed
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA.,Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Connor I White
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Robert T Batey
- Department of Chemistry and Biochemistry, University of Colorado, Campus Box 596, Boulder, CO 80309, USA
| | - Jacob C Schwartz
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| |
Collapse
|
127
|
Cammas A, Millevoi S. RNA G-quadruplexes: emerging mechanisms in disease. Nucleic Acids Res 2017; 45:1584-1595. [PMID: 28013268 PMCID: PMC5389700 DOI: 10.1093/nar/gkw1280] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 12/16/2016] [Indexed: 12/13/2022] Open
Abstract
RNA G-quadruplexes (G4s) are formed by G-rich RNA sequences in protein-coding (mRNA) and non-coding (ncRNA) transcripts that fold into a four-stranded conformation. Experimental studies and bioinformatic predictions support the view that these structures are involved in different cellular functions associated to both DNA processes (telomere elongation, recombination and transcription) and RNA post-transcriptional mechanisms (including pre-mRNA processing, mRNA turnover, targeting and translation). An increasing number of different diseases have been associated with the inappropriate regulation of RNA G4s exemplifying the potential importance of these structures on human health. Here, we review the different molecular mechanisms underlying the link between RNA G4s and human diseases by proposing several overlapping models of deregulation emerging from recent research, including (i) sequestration of RNA-binding proteins, (ii) aberrant expression or localization of RNA G4-binding proteins, (iii) repeat associated non-AUG (RAN) translation, (iv) mRNA translational blockade and (v) disabling of protein–RNA G4 complexes. This review also provides a comprehensive survey of the functional RNA G4 and their mechanisms of action. Finally, we highlight future directions for research aimed at improving our understanding on RNA G4-mediated regulatory mechanisms linked to diseases.
Collapse
Affiliation(s)
- Anne Cammas
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III-Paul Sabatier, Inserm, CRCT, Toulouse, France
| | - Stefania Millevoi
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III-Paul Sabatier, Inserm, CRCT, Toulouse, France
| |
Collapse
|
128
|
Davis JK, Broadie K. Multifarious Functions of the Fragile X Mental Retardation Protein. Trends Genet 2017; 33:703-714. [PMID: 28826631 PMCID: PMC5610095 DOI: 10.1016/j.tig.2017.07.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS), a heritable intellectual and autism spectrum disorder (ASD), results from the loss of Fragile X mental retardation protein (FMRP). This neurodevelopmental disease state exhibits neural circuit hyperconnectivity and hyperexcitability. Canonically, FMRP functions as an mRNA-binding translation suppressor, but recent findings have enormously expanded its proposed roles. Although connections between burgeoning FMRP functions remain unknown, recent advances have extended understanding of its involvement in RNA, channel, and protein binding that modulate calcium signaling, activity-dependent critical period development, and the excitation-inhibition (E/I) neural circuitry balance. In this review, we contextualize 3 years of FXS model research. Future directions extrapolated from recent advances focus on discovering links between FMRP roles to determine whether FMRP has a multitude of unrelated functions or whether combinatorial mechanisms can explain its multifaceted existence.
Collapse
Affiliation(s)
- Jenna K Davis
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235, USA.
| |
Collapse
|
129
|
Abstract
Fragile X syndrome (FXS) is the leading inherited form of intellectual disability and autism spectrum disorder, and patients can present with severe behavioural alterations, including hyperactivity, impulsivity and anxiety, in addition to poor language development and seizures. FXS is a trinucleotide repeat disorder, in which >200 repeats of the CGG motif in FMR1 leads to silencing of the gene and the consequent loss of its product, fragile X mental retardation 1 protein (FMRP). FMRP has a central role in gene expression and regulates the translation of potentially hundreds of mRNAs, many of which are involved in the development and maintenance of neuronal synaptic connections. Indeed, disturbances in neuroplasticity is a key finding in FXS animal models, and an imbalance in inhibitory and excitatory neuronal circuits is believed to underlie many of the clinical manifestations of this disorder. Our knowledge of the proteins that are regulated by FMRP is rapidly growing, and this has led to the identification of multiple targets for therapeutic intervention, some of which have already moved into clinical trials or clinical practice.
Collapse
|
130
|
Analysis of Ribosome Stalling and Translation Elongation Dynamics by Deep Learning. Cell Syst 2017; 5:212-220.e6. [DOI: 10.1016/j.cels.2017.08.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/27/2017] [Accepted: 08/04/2017] [Indexed: 01/16/2023]
|
131
|
Fan Y, Yue J, Xiao M, Han-Zhang H, Wang YV, Ma C, Deng Z, Li Y, Yu Y, Wang X, Niu S, Hua Y, Weng Z, Atadja P, Li E, Xiang B. FXR1 regulates transcription and is required for growth of human cancer cells with TP53/FXR2 homozygous deletion. eLife 2017; 6:26129. [PMID: 28767039 PMCID: PMC5595435 DOI: 10.7554/elife.26129] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 08/01/2017] [Indexed: 11/25/2022] Open
Abstract
Tumor suppressor p53 prevents cell transformation by inducing apoptosis and other responses. Homozygous TP53 deletion occurs in various types of human cancers for which no therapeutic strategies have yet been reported. TCGA database analysis shows that the TP53 homozygous deletion locus mostly exhibits co-deletion of the neighboring gene FXR2, which belongs to the Fragile X gene family. Here, we demonstrate that inhibition of the remaining family member FXR1 selectively blocks cell proliferation in human cancer cells containing homozygous deletion of both TP53 and FXR2 in a collateral lethality manner. Mechanistically, in addition to its RNA-binding function, FXR1 recruits transcription factor STAT1 or STAT3 to gene promoters at the chromatin interface and regulates transcription thus, at least partially, mediating cell proliferation. Our study anticipates that inhibition of FXR1 is a potential therapeutic approach to targeting human cancers harboring TP53 homozygous deletion. Healthy human cells employ many tricks to avoid becoming cancerous. For example, they produce proteins known as tumor suppressors, which sense if a cell shows early signs of cancer and instruct the cell to die. A gene known as TP53 produces one of the most important tumor suppressor proteins, and this gene is inactive or missing in many types of human cancer. Treating cancers that have completely lost the TP53 gene is particularly difficult. One way to develop new treatments for these conditions would be to target other proteins that these cancers need to survive; but these proteins first need to be identified. Fan et al. have now identified one such protein in human cancer cells lacking TP53. Searching databases of DNA sequences from human cancer cells revealed that those without the TP53 gene often also lose a neighboring gene called FXR2. Cancer cells survive without FXR2 because a similar gene, called FXR1, can compensate. Fan et al. therefore decided to experimentally lower the activity of the FXR1 gene and, as expected, cancer cells without TP53 and FXR2 stopped growing. Normal cells, on the other hand, were unaffected by the deletion of the FXR1 gene since FXR2 is still there. This phenomenon, in which cancer cells become vulnerable after the loss of certain genes but only because they have already lost important tumor suppressors, is called “collateral lethality”. Further experiments showed that the protein encoded by FXR1 coordinates with other proteins to activate genes that contribute to cell growth. These findings suggest new ways to treat human cancers that have lost TP53. For example, if scientists can find small molecules that inhibit the protein encoded by FXR1 and show that these molecules can block the growth of tumors lacking TP53 and FXR2, this could eventually lead to a new anticancer drug. However, like any new drug, these small molecule inhibitors would also need to be extensively tested before they could be taken into human clinical trials.
Collapse
Affiliation(s)
- Yichao Fan
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Jiao Yue
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Mengtao Xiao
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Han Han-Zhang
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Yao Vickie Wang
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Chun Ma
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Zhilin Deng
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Yingxiang Li
- Department of Bioinformatics, Tongji University, Shanghai, China
| | - Yanyan Yu
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Xinghao Wang
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Shen Niu
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Youjia Hua
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Zhiping Weng
- Department of Bioinformatics, Tongji University, Shanghai, China
| | - Peter Atadja
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - En Li
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| | - Bin Xiang
- Epigenetic Discovery, China Novartis Institutes for BioMedical Research, Shanghai, China
| |
Collapse
|
132
|
Wheeler A, Raspa M, Hagerman R, Mailick M, Riley C. Implications of the FMR1 Premutation for Children, Adolescents, Adults, and Their Families. Pediatrics 2017; 139:S172-S182. [PMID: 28814538 PMCID: PMC5621635 DOI: 10.1542/peds.2016-1159d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Given the nature of FMR1 gene expansions, most biological mothers, and often multiple other family members of children with fragile X syndrome (FXS), will have a premutation, which may increase individual and family vulnerabilities. This article summarizes important gaps in knowledge and notes potential implications for pediatric providers with regard to developmental and medical risks for children and adolescents with an FMR1 premutation, including possible implications into adulthood. METHODS A structured electronic literature search was conducted on FMR1 pre- and full mutations, yielding a total of 306 articles examined. Of these, 116 focused primarily on the premutation and are included in this review. RESULTS Based on the literature review, 5 topic areas are discussed: genetics and epidemiology; phenotypic characteristics of individuals with the premutation; implications for carrier parents of children with FXS; implications for the extended family; and implications for pediatricians. CONCLUSIONS Although the premutation phenotype is typically less severe in clinical presentation than in FXS, premutation carriers are much more common and are therefore more likely to be seen in a typical pediatric practice. In addition, there is a wide range of medical, cognitive/developmental, and psychiatric associated features that individuals with a premutation are at increased risk for having, which underscores the importance of awareness on the part of pediatricians in identifying and monitoring premutation carriers and recognizing the impact this identification may have on family members.
Collapse
Affiliation(s)
- Anne Wheeler
- RTI International, Research Triangle Park, North Carolina;
| | - Melissa Raspa
- RTI International, Research Triangle Park, North Carolina
| | - Randi Hagerman
- MIND Institute, University of California at Davis, Sacramento, California
| | - Marsha Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Catharine Riley
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
| |
Collapse
|
133
|
Simsek D, Tiu GC, Flynn RA, Byeon GW, Leppek K, Xu AF, Chang HY, Barna M. The Mammalian Ribo-interactome Reveals Ribosome Functional Diversity and Heterogeneity. Cell 2017; 169:1051-1065.e18. [PMID: 28575669 PMCID: PMC5548193 DOI: 10.1016/j.cell.2017.05.022] [Citation(s) in RCA: 265] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 03/13/2017] [Accepted: 05/14/2017] [Indexed: 11/19/2022]
Abstract
During eukaryotic evolution, ribosomes have considerably increased in size, forming a surface-exposed ribosomal RNA (rRNA) shell of unknown function, which may create an interface for yet uncharacterized interacting proteins. To investigate such protein interactions, we establish a ribosome affinity purification method that unexpectedly identifies hundreds of ribosome-associated proteins (RAPs) from categories including metabolism and cell cycle, as well as RNA- and protein-modifying enzymes that functionally diversify mammalian ribosomes. By further characterizing RAPs, we discover the presence of ufmylation, a metazoan-specific post-translational modification (PTM), on ribosomes and define its direct substrates. Moreover, we show that the metabolic enzyme, pyruvate kinase muscle (PKM), interacts with sub-pools of endoplasmic reticulum (ER)-associated ribosomes, exerting a non-canonical function as an RNA-binding protein in the translation of ER-destined mRNAs. Therefore, RAPs interconnect one of life's most ancient molecular machines with diverse cellular processes, providing an additional layer of regulatory potential to protein expression.
Collapse
Affiliation(s)
- Deniz Simsek
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Gerald C Tiu
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Ryan A Flynn
- Center for Personal Dynamic Regulomes and Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gun W Byeon
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Kathrin Leppek
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Adele F Xu
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes and Program in Epithelial Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
| |
Collapse
|
134
|
Wang X, Mu Y, Sun M, Han J. Bidirectional regulation of fragile X mental retardation protein phosphorylation controls rhodopsin homoeostasis. J Mol Cell Biol 2017; 9:104-116. [PMID: 27702760 DOI: 10.1093/jmcb/mjw041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/29/2016] [Indexed: 01/03/2023] Open
Abstract
Homoeostatic regulation of the light sensor, rhodopsin, is critical for the maintenance of light sensitivity and survival of photoreceptors. The major fly rhodopsin, Rh1, undergoes light-induced endocytosis and degradation, but its protein and mRNA levels remain constant during light/dark cycles. It is not clear how translation of Rh1 is regulated. Here, we show that adult photoreceptors maintain a constant, abundant quantity of ninaE mRNA, which encodes Rh1. We demonstrate that the Fmr1 protein associates with ninaE mRNA and represses its translation. Further, light exposure triggers a calcium-dependent dephosphorylation of Fmr1, which relieves suppression of Rh1 translation. We demonstrate that Mts, the catalytic subunit of protein phosphatase 2A (PP2A), mediates light-induced Fmr1 dephosphorylation in a regulatory B subunit of PP2A (CKa)-dependent manner. Finally, we show that blocking light-induced Rh1 translation results in reduced light sensitivity. Our results reveal the molecular mechanism of Rh1 homoeostasis and physiological consequence of Rh1 dysregulation.
Collapse
Affiliation(s)
- Xiao Wang
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Yawen Mu
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Mengshi Sun
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Junhai Han
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| |
Collapse
|
135
|
Pugin A, Faundes V, Santa María L, Curotto B, Aliaga S, Salas I, Soto P, Bravo P, Peña M, Alliende M. Clinical, molecular, and pharmacological aspects of FMR1 -related disorders. NEUROLOGÍA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.nrleng.2014.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
|
136
|
Donlin-Asp PG, Rossoll W, Bassell GJ. Spatially and temporally regulating translation via mRNA-binding proteins in cellular and neuronal function. FEBS Lett 2017; 591:1508-1525. [PMID: 28295262 DOI: 10.1002/1873-3468.12621] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/20/2022]
Abstract
Coordinated regulation of mRNA localization and local translation are essential steps in cellular asymmetry and function. It is increasingly evident that mRNA-binding proteins play critical functions in controlling the fate of mRNA, including when and where translation occurs. In this review, we discuss the robust and complex roles that mRNA-binding proteins play in the regulation of local translation that impact cellular function in vertebrates. First, we discuss the role of local translation in cellular polarity and possible links to vertebrate development and patterning. Next, we discuss the expanding role for local protein synthesis in neuronal development and function, with special focus on how a number of neurological diseases have given us insight into the importance of translational regulation. Finally, we discuss the ever-increasing set of tools to study regulated translation and how these tools will be vital in pushing forward and addressing the outstanding questions in the field.
Collapse
Affiliation(s)
- Paul G Donlin-Asp
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Wilfried Rossoll
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| |
Collapse
|
137
|
Song J, Perreault JP, Topisirovic I, Richard S. RNA G-quadruplexes and their potential regulatory roles in translation. ACTA ACUST UNITED AC 2016; 4:e1244031. [PMID: 28090421 PMCID: PMC5173311 DOI: 10.1080/21690731.2016.1244031] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/26/2016] [Accepted: 09/28/2016] [Indexed: 12/11/2022]
Abstract
DNA guanine (G)-rich 4-stranded helical nucleic acid structures called G-quadruplexes (G4), have been extensively studied during the last decades. However, emerging evidence reveals that 5′- and 3′-untranslated regions (5′- and 3′-UTRs) as well as open reading frames (ORFs) contain putative RNA G-quadruplexes. These stable secondary structures play key roles in telomere homeostasis and RNA metabolism including pre-mRNA splicing, polyadenylation, mRNA targeting and translation. Interestingly, multiple RNA binding proteins such as nucleolin, FMRP, DHX36, and Aven were identified to bind RNA G-quadruplexes. Moreover, accumulating reports suggest that RNA G-quadruplexes regulate translation in cap-dependent and -independent manner. Herein, we discuss potential roles of RNA G-quadruplexes and associated trans-acting factors in the regulation of mRNA translation.
Collapse
Affiliation(s)
- Jingwen Song
- Terry Fox Molecular Oncology Group and Segal Cancer Center, McGill University, Montréal, Québec, Canada; Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, McGill University, Montréal, Québec, Canada; Department of Oncology, McGill University, Montréal, Québec, Canada; Department of Medicine, McGill University, Montréal, Québec, Canada
| | | | - Ivan Topisirovic
- Terry Fox Molecular Oncology Group and Segal Cancer Center, McGill University, Montréal, Québec, Canada; Department of Oncology, McGill University, Montréal, Québec, Canada; Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Stéphane Richard
- Terry Fox Molecular Oncology Group and Segal Cancer Center, McGill University, Montréal, Québec, Canada; Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, McGill University, Montréal, Québec, Canada; Department of Oncology, McGill University, Montréal, Québec, Canada; Department of Medicine, McGill University, Montréal, Québec, Canada
| |
Collapse
|
138
|
Dean DD, Muthuswamy S, Agarwal S. Fragile X syndrome: Current insight. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2016. [DOI: 10.1016/j.ejmhg.2016.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
|
139
|
Bramham CR, Jensen KB, Proud CG. Tuning Specific Translation in Cancer Metastasis and Synaptic Memory: Control at the MNK-eIF4E Axis. Trends Biochem Sci 2016; 41:847-858. [PMID: 27527252 DOI: 10.1016/j.tibs.2016.07.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 02/07/2023]
Abstract
The eukaryotic translation initiation factor (eIF) 4E, which binds to the 5'-cap of mRNA, undergoes phosphorylation on a single conserved serine, executed by the mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs). However, the functional consequences and physiological roles of MNK signalling have remained obscure. Now, new pharmacological and genetic tools have provided unprecedented insights into the function of MNKs and eIF4E phosphorylation. The studies suggest that MNKs control the translation of specific mRNAs in cancer metastasis and neuronal synaptic plasticity by a novel mechanism involving the regulation of the translational repressor, cytoplasmic fragile-X protein-interacting protein 1 (CYFIP1). These recent breakthroughs go a long way to resolving the longstanding enigma and controversy surrounding the function of the MNK-eIF4E axis in cancer cell biology and neurobiology.
Collapse
Affiliation(s)
- Clive R Bramham
- Department of Biomedicine and KG Jebsen Centre for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway.
| | - Kirk B Jensen
- South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Christopher G Proud
- South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia; School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| |
Collapse
|
140
|
Francisco-Velilla R, Fernandez-Chamorro J, Ramajo J, Martinez-Salas E. The RNA-binding protein Gemin5 binds directly to the ribosome and regulates global translation. Nucleic Acids Res 2016; 44:8335-51. [PMID: 27507887 PMCID: PMC5041490 DOI: 10.1093/nar/gkw702] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/31/2016] [Indexed: 12/21/2022] Open
Abstract
RNA-binding proteins (RBPs) play crucial roles in all organisms. The protein Gemin5 harbors two functional domains. The N-terminal domain binds to snRNAs targeting them for snRNPs assembly, while the C-terminal domain binds to IRES elements through a non-canonical RNA-binding site. Here we report a comprehensive view of the Gemin5 interactome; most partners copurified with the N-terminal domain via RNA bridges. Notably, Gemin5 sediments with the subcellular ribosome fraction, and His-Gemin5 binds to ribosome particles via its N-terminal domain. The interaction with the ribosome was lost in F381A and Y474A Gemin5 mutants, but not in W14A and Y15A. Moreover, the ribosomal proteins L3 and L4 bind directly with Gemin5, and conversely, Gemin5 mutants impairing the binding to the ribosome are defective in the interaction with L3 and L4. The overall polysome profile was affected by Gemin5 depletion or overexpression, concomitant to an increase or a decrease, respectively, of global protein synthesis. Gemin5, and G5-Nter as well, were detected on the polysome fractions. These results reveal the ribosome-binding capacity of the N-ter moiety, enabling Gemin5 to control global protein synthesis. Our study uncovers a crosstalk between this protein and the ribosome, and provides support for the view that Gemin5 may control translation elongation.
Collapse
Affiliation(s)
| | | | - Jorge Ramajo
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049-Madrid, Spain
| | | |
Collapse
|
141
|
Anderson BR, Chopra P, Suhl JA, Warren ST, Bassell GJ. Identification of consensus binding sites clarifies FMRP binding determinants. Nucleic Acids Res 2016; 44:6649-59. [PMID: 27378784 PMCID: PMC5001617 DOI: 10.1093/nar/gkw593] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/17/2016] [Indexed: 12/30/2022] Open
Abstract
Fragile X mental retardation protein (FMRP) is a multifunctional RNA-binding protein with crucial roles in neuronal development and function. Efforts aimed at elucidating how FMRP target mRNAs are selected have produced divergent sets of target mRNA and putative FMRP-bound motifs, and a clear understanding of FMRP's binding determinants has been lacking. To clarify FMRP's binding to its target mRNAs, we produced a shared dataset of FMRP consensus binding sequences (FCBS), which were reproducibly identified in two published FMRP CLIP sequencing datasets. This comparative dataset revealed that of the various sequence and structural motifs that have been proposed to specify FMRP binding, the short sequence motifs TGGA and GAC were corroborated, and a novel TAY motif was identified. In addition, the distribution of the FCBS set demonstrates that FMRP preferentially binds to the coding region of its targets but also revealed binding along 3' UTRs in a subset of target mRNAs. Beyond probing these putative motifs, the FCBS dataset of reproducibly identified FMRP binding sites is a valuable tool for investigating FMRP targets and function.
Collapse
Affiliation(s)
- Bart R Anderson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Pankaj Chopra
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Joshua A Suhl
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Stephen T Warren
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| |
Collapse
|
142
|
Tabet R, Moutin E, Becker JAJ, Heintz D, Fouillen L, Flatter E, Krężel W, Alunni V, Koebel P, Dembélé D, Tassone F, Bardoni B, Mandel JL, Vitale N, Muller D, Le Merrer J, Moine H. Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons. Proc Natl Acad Sci U S A 2016; 113:E3619-28. [PMID: 27233938 PMCID: PMC4932937 DOI: 10.1073/pnas.1522631113] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by the absence of the Fragile X Mental Retardation Protein (FMRP) in neurons. In the mouse, the lack of FMRP is associated with an excessive translation of hundreds of neuronal proteins, notably including postsynaptic proteins. This local protein synthesis deregulation is proposed to underlie the observed defects of glutamatergic synapse maturation and function and to affect preferentially the hundreds of mRNA species that were reported to bind to FMRP. How FMRP impacts synaptic protein translation and which mRNAs are most important for the pathology remain unclear. Here we show by cross-linking immunoprecipitation in cortical neurons that FMRP is mostly associated with one unique mRNA: diacylglycerol kinase kappa (Dgkκ), a master regulator that controls the switch between diacylglycerol and phosphatidic acid signaling pathways. The absence of FMRP in neurons abolishes group 1 metabotropic glutamate receptor-dependent DGK activity combined with a loss of Dgkκ expression. The reduction of Dgkκ in neurons is sufficient to cause dendritic spine abnormalities, synaptic plasticity alterations, and behavior disorders similar to those observed in the FXS mouse model. Overexpression of Dgkκ in neurons is able to rescue the dendritic spine defects of the Fragile X Mental Retardation 1 gene KO neurons. Together, these data suggest that Dgkκ deregulation contributes to FXS pathology and support a model where FMRP, by controlling the translation of Dgkκ, indirectly controls synaptic proteins translation and membrane properties by impacting lipid signaling in dendritic spine.
Collapse
Affiliation(s)
- Ricardos Tabet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Enora Moutin
- Department of Basic Neuroscience, University of Geneva, 1211 Geneva 4, Switzerland
| | - Jérôme A J Becker
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, Plateforme Métabolomique, Unité Propre de Recherche (UPR) 2357 CNRS, Université de Strasbourg, 67082 Strasbourg, France
| | - Laetitia Fouillen
- Laboratoire de Biogènese Membranaire; UMR 5200 CNRS, Plateforme Métabolome, Université de Bordeaux, 33140 Villenave D'Ornon, France
| | - Eric Flatter
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Wojciech Krężel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Violaine Alunni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Pascale Koebel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Doulaye Dembélé
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis Medical Center, Sacramento, CA 95817
| | - Barbara Bardoni
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, University of Nice Sophia-Antipolis, CNRS Laboratoire International Associé (LIA) Neogenex, 06560 Valbonne, France
| | - Jean-Louis Mandel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, 75005 Paris, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212 CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Dominique Muller
- Department of Basic Neuroscience, University of Geneva, 1211 Geneva 4, Switzerland
| | - Julie Le Merrer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Hervé Moine
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France;
| |
Collapse
|
143
|
RNA Secondary Structure Modulates FMRP's Bi-Functional Role in the MicroRNA Pathway. Int J Mol Sci 2016; 17:ijms17060985. [PMID: 27338369 PMCID: PMC4926514 DOI: 10.3390/ijms17060985] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/23/2016] [Accepted: 06/14/2016] [Indexed: 11/28/2022] Open
Abstract
MicroRNAs act by post-transcriptionally regulating the gene expression of 30%–60% of mammalian genomes. MicroRNAs are key regulators in all cellular processes, though the mechanism by which the cell activates or represses microRNA-mediated translational regulation is poorly understood. In this review, we discuss the RNA binding protein Fragile X Mental Retardation Protein (FMRP) and its role in microRNA-mediated translational regulation. Historically, FMRP is known to function as a translational suppressor. However, emerging data suggests that FMRP has both an agonistic and antagonistic role in regulating microRNA-mediated translational suppression. This bi-functional role is dependent on FMRP’s interaction with the RNA helicase Moloney leukemia virus 10 (MOV10), which modifies the structural landscape of bound mRNA, therefore facilitating or inhibiting its association with the RNA-Induced Silencing Complex.
Collapse
|
144
|
Kashima R, Roy S, Ascano M, Martinez-Cerdeno V, Ariza-Torres J, Kim S, Louie J, Lu Y, Leyton P, Bloch KD, Kornberg TB, Hagerman PJ, Hagerman R, Lagna G, Hata A. Augmented noncanonical BMP type II receptor signaling mediates the synaptic abnormality of fragile X syndrome. Sci Signal 2016; 9:ra58. [PMID: 27273096 DOI: 10.1126/scisignal.aaf6060] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Epigenetic silencing of fragile X mental retardation 1 (FMR1) causes fragile X syndrome (FXS), a common inherited form of intellectual disability and autism. FXS correlates with abnormal synapse and dendritic spine development, but the molecular link between the absence of the FMR1 product FMRP, an RNA binding protein, and the neuropathology is unclear. We found that the messenger RNA encoding bone morphogenetic protein type II receptor (BMPR2) is a target of FMRP. Depletion of FMRP increased BMPR2 abundance, especially that of the full-length isoform that bound and activated LIM domain kinase 1 (LIMK1), a component of the noncanonical BMP signal transduction pathway that stimulates actin reorganization to promote neurite outgrowth and synapse formation. Heterozygosity for BMPR2 rescued the morphological abnormalities in neurons both in Drosophila and in mouse models of FXS, as did the postnatal pharmacological inhibition of LIMK1 activity. Compared with postmortem prefrontal cortex tissue from healthy subjects, the amount of full-length BMPR2 and of a marker of LIMK1 activity was increased in this brain region from FXS patients. These findings suggest that increased BMPR2 signal transduction is linked to FXS and that the BMPR2-LIMK1 pathway is a putative therapeutic target in patients with FXS and possibly other forms of autism.
Collapse
Affiliation(s)
- Risa Kashima
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Sougata Roy
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Manuel Ascano
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Veronica Martinez-Cerdeno
- Institute for Pediatric Regenerative Medicine, Department of Pathology, University of California, Davis, Davis, CA 95817, USA. MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California, Davis, Davis, CA 95817, USA
| | - Jeanelle Ariza-Torres
- Institute for Pediatric Regenerative Medicine, Department of Pathology, University of California, Davis, Davis, CA 95817, USA
| | - Sunghwan Kim
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Justin Louie
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yao Lu
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Patricio Leyton
- Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Kenneth D Bloch
- Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA 95817, USA
| | - Randi Hagerman
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California, Davis, Davis, CA 95817, USA
| | - Giorgio Lagna
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Akiko Hata
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA.
| |
Collapse
|
145
|
Napthine S, Treffers EE, Bell S, Goodfellow I, Fang Y, Firth AE, Snijder EJ, Brierley I. A novel role for poly(C) binding proteins in programmed ribosomal frameshifting. Nucleic Acids Res 2016; 44:5491-503. [PMID: 27257056 PMCID: PMC4937337 DOI: 10.1093/nar/gkw480] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/18/2016] [Indexed: 01/16/2023] Open
Abstract
Translational control through programmed ribosomal frameshifting (PRF) is exploited widely by viruses and increasingly documented in cellular genes. Frameshifting is induced by mRNA secondary structures that compromise ribosome fidelity during decoding of a heptanucleotide 'slippery' sequence. The nsp2 PRF signal of porcine reproductive and respiratory syndrome virus is distinctive in directing both -2 and -1 PRF and in its requirement for a trans-acting protein factor, the viral replicase subunit nsp1β. Here we show that the the trans-activation of frameshifting is carried out by a protein complex composed of nsp1β and a cellular poly(C) binding protein (PCBP). From the results of in vitro translation and electrophoretic mobility shift assays, we demonstrate that a PCBP/nsp1β complex binds to a C-rich sequence downstream of the slippery sequence and here mimics the activity of a structured mRNA stimulator of PRF. This is the first description of a role for a trans-acting cellular protein in PRF. The discovery broadens the repertoire of activities associated with poly(C) binding proteins and prototypes a new class of virus-host interactions.
Collapse
Affiliation(s)
- Sawsan Napthine
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Emmely E Treffers
- Department of Medical Microbiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Susanne Bell
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Ian Goodfellow
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Ying Fang
- College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5705, USA
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Eric J Snijder
- Department of Medical Microbiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Ian Brierley
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| |
Collapse
|
146
|
Ishimura R, Nagy G, Dotu I, Chuang JH, Ackerman SL. Activation of GCN2 kinase by ribosome stalling links translation elongation with translation initiation. eLife 2016; 5. [PMID: 27085088 PMCID: PMC4917338 DOI: 10.7554/elife.14295] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/14/2016] [Indexed: 12/17/2022] Open
Abstract
Ribosome stalling during translation has recently been shown to cause neurodegeneration, yet the signaling pathways triggered by stalled elongation complexes are unknown. To investigate these pathways we analyzed the brain of C57BL/6J-Gtpbp2nmf205-/- mice in which neuronal elongation complexes are stalled at AGA codons due to deficiencies in a tRNAArgUCU tRNA and GTPBP2, a mammalian ribosome rescue factor. Increased levels of phosphorylation of eIF2α (Ser51) were detected prior to neurodegeneration in these mice and transcriptome analysis demonstrated activation of ATF4, a key transcription factor in the integrated stress response (ISR) pathway. Genetic experiments showed that this pathway was activated by the eIF2α kinase, GCN2, in an apparent deacylated tRNA-independent fashion. Further we found that the ISR attenuates neurodegeneration in C57BL/6J-Gtpbp2nmf205-/- mice, underscoring the importance of cellular and stress context on the outcome of activation of this pathway. These results demonstrate the critical interplay between translation elongation and initiation in regulating neuron survival during cellular stress. DOI:http://dx.doi.org/10.7554/eLife.14295.001 Information stored in DNA is used to make proteins in a two-step process. First, the DNA is copied to make molecules of messenger ribonucleic acid (or messenger RNA for short). Next, machines called ribosomes use the messenger RNAs as templates to assemble chains of amino acids – the building blocks of proteins – in a process called translation. Another type of RNA molecule called transfer RNA carries each amino acid to the ribosomes. If a specific transfer RNA is not available for translation at the right time, the ribosome might stall as it moves along the messenger RNA. At this point, the ribosome needs to be restarted or it will fall off the mRNA without finishing the protein. In 2014, a group of researchers reported that certain types of brain cells are very sensitive to ribosome stalling, and tend to die if translation does not continue. A protein called GTPBP2 was shown to play an important role in restarting stalled ribosomes in these cells. Here, Ishimura, Nagy et al. – including some of the researchers from the earlier work – investigated the molecular pathways that ribosome stalling triggers in brain cells using mutant mice that lacked the GTPBP2 protein. The experiments show that ribosome stalling activates an enzyme known as GCN2, which was already known to sense other types of malfunctions in cellular processes. Ishimura, Nagy et al. also show that GCN2 triggers stress responses in the cells by activating a communication system called the ATF4 pathway. This pathway protects the cells from damage, and its absence results in more rapid cell deterioration and death. The next challenges are to understand the exact mechanism by which GCN2 senses stalled ribosomes, and to find out how ribosome stalling causes the death of brain cells. DOI:http://dx.doi.org/10.7554/eLife.14295.002
Collapse
Affiliation(s)
- Ryuta Ishimura
- Howard Hughes Medical Institute, The Jackson Laboratory for Mammalian Genetics, Bar Harbor, United States
| | - Gabor Nagy
- Howard Hughes Medical Institute, The Jackson Laboratory for Mammalian Genetics, Bar Harbor, United States
| | - Ivan Dotu
- Research Programme on Biomedical Informatics, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic Medicine, Farmington, United States.,Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, United States
| | - Susan L Ackerman
- Howard Hughes Medical Institute, The Jackson Laboratory for Mammalian Genetics, Bar Harbor, United States.,Department of Cell and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States.,Section of Neurobiology, University of California, La Jolla, United States
| |
Collapse
|
147
|
Wan RP, Zhou LT, Yang HX, Zhou YT, Ye SH, Zhao QH, Gao MM, Liao WP, Yi YH, Long YS. Involvement of FMRP in Primary MicroRNA Processing via Enhancing Drosha Translation. Mol Neurobiol 2016; 54:2585-2594. [PMID: 26993298 DOI: 10.1007/s12035-016-9855-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 03/11/2016] [Indexed: 12/21/2022]
Abstract
Fragile X mental retardation protein (FMRP), associated with fragile X syndrome, is known as an RNA-binding protein to regulate gene expression at post-transcriptional level in the brain. FMRP is also involved in microRNA (miRNA) biogenesis during the process of precursor miRNA (pre-miRNA) into mature miRNA. However, there is no description of the effect of FMRP on primary miRNA (pri-miRNA) processing. Here, we uncover a novel role of FMRP in pri-miRNA processing via controlling Drosha translation. We show that the expression of DROSHA protein, instead of its messenger RNA (mRNA) transcripts, is downregulated in both the hippocampus of Fmr1-knockout mice and the FMRP-knockdown Neuro-2a cells. Overexpression or knockdown FMRP does not alter Drosha mRNA stability. Immunoprecipitation and polysome analyses demonstrate that FMRP binds to the Drosha mRNA and enhances its translation. Additionally, we show that loss of FMRP in Fmr1-deficient mice results in the accumulation of three in six analyzed pri-miRNAs and the reduction of the corresponding pre-miRNAs and mature miRNAs. Thus, our data suggest that FMRP is involved in pri-miRNA processing via enhancing DROSHA expression that may play an important role in fragile X syndrome.
Collapse
Affiliation(s)
- Rui-Ping Wan
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China.,Department of Children's Rehabilitation, Foshan Maternity and Child Healthcare Hospital Affiliated to Southern Medical University, Foshan, China
| | - Lin-Tao Zhou
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Hai-Xuan Yang
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Yong-Ting Zhou
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Shun-Hua Ye
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Qi-Hua Zhao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Mei-Mei Gao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Wei-Ping Liao
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China
| | - Yong-Hong Yi
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China.
| | - Yue-Sheng Long
- Institute of Neuroscience and The Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, 250 Changang East Road, Guangzhou, 510260, China.
| |
Collapse
|
148
|
Sun MK, Hongpaisan J, Alkon DL. Rescue of Synaptic Phenotypes and Spatial Memory in Young Fragile X Mice. ACTA ACUST UNITED AC 2016; 357:300-10. [PMID: 26941170 DOI: 10.1124/jpet.115.231100] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/02/2016] [Indexed: 01/01/2023]
Abstract
Fragile X syndrome (FXS) is characterized by synaptic immaturity, cognitive impairment, and behavioral changes. The disorder is caused by transcriptional shutdown in neurons of thefragile X mental retardation 1gene product, fragile X mental retardation protein. Fragile X mental retardation protein is a repressor of dendritic mRNA translation and its silencing leads to dysregulation of synaptically driven protein synthesis and impairments of intellect, cognition, and behavior, and FXS is a disorder that currently has no effective therapeutics. Here, young fragile X mice were treated with chronic bryostatin-1, a relatively selective protein kinase Cεactivator, which induces synaptogenesis and synaptic maturation/repair. Chronic treatment with bryostatin-1 rescues young fragile X mice from the disorder phenotypes, including normalization of most FXS abnormalities in 1) hippocampal brain-derived neurotrophic factor expression, 2) postsynaptic density-95 levels, 3) transformation of immature dendritic spines to mature synapses, 4) densities of the presynaptic and postsynaptic membranes, and 5) spatial learning and memory. The therapeutic effects were achieved without downregulation of metabotropic glutamate receptor (mGluR) 5 in the hippocampus and are more dramatic than those of a late-onset treatment in adult fragile X mice. mGluR5 expression was in fact lower in fragile X mice and its expression was restored with the bryostatin-1 treatment. Our results show that synaptic and cognitive function of young FXS mice can be normalized through pharmacological treatment without downregulation of mGluR5 and that bryostatin-1-like agents may represent a novel class of drugs to treat fragile X mental retardation at a young age and in adults.
Collapse
Affiliation(s)
- Miao-Kun Sun
- Blanchette Rockefeller Neurosciences Institute, Morgantown, West Virginia
| | - Jarin Hongpaisan
- Blanchette Rockefeller Neurosciences Institute, Morgantown, West Virginia
| | - Daniel L Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, West Virginia
| |
Collapse
|
149
|
Call CL, Hyson RL. Activity-dependent regulation of calcium and ribosomes in the chick cochlear nucleus. Neuroscience 2016; 316:201-8. [PMID: 26739326 DOI: 10.1016/j.neuroscience.2015.12.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 01/25/2023]
Abstract
Cochlea removal results in the death of 20-30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM). Two potentially cytotoxic events, a dramatic rise in intracellular calcium concentration ([Ca(2+)]i) and a decline in the integrity of ribosomes are observed within 1h of deafferentation. Glutamatergic input from the auditory nerve has been shown to preserve NM neuron health by activating metabotropic glutamate receptors (mGluRs), maintaining both normal [Ca(2+)]i and ribosomal integrity. One interpretation of these results is that a common mGluR-activated signaling cascade is required for the maintenance of both [Ca(2+)]i and ribosomal integrity. This could happen if both responses are influenced directly by a common messenger, or if the loss of mGluR activation causes changes in one component that secondarily causes changes in the other. The present studies tested this common-mediator hypothesis in slice preparations by examining activity-dependent regulation of [Ca(2+)]i and ribosomes in the same tissue after selectively blocking group I mGluRs (1-Aminoindan-1,5-dicarboxylic acid (AIDA)) or group II mGluRs (LY 341495) during unilateral auditory nerve stimulation. Changes in [Ca(2+)]i of NM neurons were measured using fura-2 ratiometric calcium imaging and the tissue was subsequently processed for Y10B immunoreactivity (Y10B-ir), an antibody that recognizes a ribosomal epitope. The group I mGluR antagonist blocked the activity-dependent regulation of both [Ca(2+)]i and Y10B-ir, but the group II antagonist blocked only the activity-dependent regulation of Y10B-ir. That is, even when group II receptors were blocked, stimulation continued to maintain low [Ca(2+)]i, but it did not maintain Y10B-ir. These results suggest a dissociation in how calcium and ribosomes are regulated in NM neurons and that ribosomes can be regulated through a mechanism that is independent of calcium regulation.
Collapse
Affiliation(s)
- C L Call
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - R L Hyson
- Department of Psychology, Florida State University, Tallahassee, FL, USA.
| |
Collapse
|
150
|
Kanekura K, Yagi T, Cammack AJ, Mahadevan J, Kuroda M, Harms MB, Miller TM, Urano F. Poly-dipeptides encoded by the C9ORF72 repeats block global protein translation. Hum Mol Genet 2016; 25:1803-13. [PMID: 26931465 PMCID: PMC4986334 DOI: 10.1093/hmg/ddw052] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 02/15/2016] [Indexed: 11/12/2022] Open
Abstract
The expansion of the GGGGCC hexanucleotide repeat in the non-coding region of the Chromosome 9 open-reading frame 72 (C9orf72) gene is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). This genetic alteration leads to the accumulation of five types of poly-dipeptides translated from the GGGGCC hexanucleotide repeat. Among these, poly-proline-arginine (poly-PR) and poly-glycine-arginine (poly-GR) peptides are known to be neurotoxic. However, the mechanisms of neurotoxicity associated with these poly-dipeptides are not clear. A proteomics approach identified a number of interacting proteins with poly-PR peptide, including mRNA-binding proteins, ribosomal proteins, translation initiation factors and translation elongation factors. Immunostaining of brain sections from patients with C9orf72 ALS showed that poly-GR was colocalized with a mRNA-binding protein, hnRNPA1. In vitro translation assays showed that poly-PR and poly-GR peptides made insoluble complexes with mRNA, restrained the access of translation factors to mRNA, and blocked protein translation. Our results demonstrate that impaired protein translation mediated by poly-PR and poly-GR peptides plays a role in neurotoxicity and reveal that the pathways altered by the poly-dipeptides-mRNA complexes are potential therapeutic targets for treatment of C9orf72 FTD/ALS.
Collapse
Affiliation(s)
- Kohsuke Kanekura
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Department of Molecular Pathology, Tokyo Medical University, Tokyo 160-8402, Japan and
| | - Takuya Yagi
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research
| | - Alexander J Cammack
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Jana Mahadevan
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research
| | - Masahiko Kuroda
- Department of Molecular Pathology, Tokyo Medical University, Tokyo 160-8402, Japan and
| | - Matthew B Harms
- Department of Neurology, Columbia University College of Physicians and Surgeon, New York, NY 10032, USA
| | - Timothy M Miller
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Fumihiko Urano
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Department of Pathology and Immunology and
| |
Collapse
|