1
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Susanto TT, Hung V, Levine AG, Chen Y, Kerr CH, Yoo Y, Oses-Prieto JA, Fromm L, Zhang Z, Lantz TC, Fujii K, Wernig M, Burlingame AL, Ruggero D, Barna M. RAPIDASH: Tag-free enrichment of ribosome-associated proteins reveals composition dynamics in embryonic tissue, cancer cells, and macrophages. Mol Cell 2024; 84:3545-3563.e25. [PMID: 39260367 PMCID: PMC11460945 DOI: 10.1016/j.molcel.2024.08.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 06/25/2024] [Accepted: 08/20/2024] [Indexed: 09/13/2024]
Abstract
Ribosomes are emerging as direct regulators of gene expression, with ribosome-associated proteins (RAPs) allowing ribosomes to modulate translation. Nevertheless, a lack of technologies to enrich RAPs across sample types has prevented systematic analysis of RAP identities, dynamics, and functions. We have developed a label-free methodology called RAPIDASH to enrich ribosomes and RAPs from any sample. We applied RAPIDASH to mouse embryonic tissues and identified hundreds of potential RAPs, including Dhx30 and Llph, two forebrain RAPs important for neurodevelopment. We identified a critical role of LLPH in neural development linked to the translation of genes with long coding sequences. In addition, we showed that RAPIDASH can identify ribosome changes in cancer cells. Finally, we characterized ribosome composition remodeling during immune cell activation and observed extensive changes post-stimulation. RAPIDASH has therefore enabled the discovery of RAPs in multiple cell types, tissues, and stimuli and is adaptable to characterize ribosome remodeling in several contexts.
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Affiliation(s)
- Teodorus Theo Susanto
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Victoria Hung
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew G Levine
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA; Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Yuxiang Chen
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Craig H Kerr
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yongjin Yoo
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Lisa Fromm
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
| | - Zijian Zhang
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Travis C Lantz
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kotaro Fujii
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Davide Ruggero
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
| | - Maria Barna
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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2
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Scarpitti MR, Pastore B, Tang W, Kearse MG. Characterization of ribosome stalling and no-go mRNA decay stimulated by the fragile X protein, FMRP. J Biol Chem 2024; 300:107540. [PMID: 38971316 PMCID: PMC11338112 DOI: 10.1016/j.jbc.2024.107540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 06/22/2024] [Accepted: 06/29/2024] [Indexed: 07/08/2024] Open
Abstract
Loss of functional fragile X mental retardation protein (FMRP) causes fragile X syndrome and is the leading monogenic cause of autism spectrum disorders and intellectual disability. FMRP is most notably a translational repressor and is thought to inhibit translation elongation by stalling ribosomes as FMRP-bound polyribosomes from brain tissue are resistant to puromycin and nuclease treatment. Here, we present data showing that the C-terminal noncanonical RNA-binding domain of FMRP is essential and sufficient to induce puromycin-resistant mRNA•ribosome complexes. Given that stalled ribosomes can stimulate ribosome collisions and no-go mRNA decay (NGD), we tested the ability of FMRP to drive NGD of its target transcripts in neuroblastoma cells. Indeed, FMRP and ribosomal proteins, but not poly(A)-binding protein, were enriched in isolated nuclease-resistant disomes compared to controls. Using siRNA knockdown and RNA-seq, we identified 16 putative FMRP-mediated NGD substrates, many of which encode proteins involved in neuronal development and function. Increased mRNA stability of four putative substrates was also observed when either FMRP was depleted or NGD was prevented via RNAi. Taken together, these data support that FMRP stalls ribosomes but only stimulates NGD of a small select set of transcripts, revealing a minor role of FMRP that would be misregulated in fragile X syndrome.
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Affiliation(s)
- MaKenzie R Scarpitti
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Benjamin Pastore
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Wen Tang
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Michael G Kearse
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
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3
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Chakraborty S, Mishra J, Roy A, Niharika, Manna S, Baral T, Nandi P, Patra S, Patra SK. Liquid-liquid phase separation in subcellular assemblages and signaling pathways: Chromatin modifications induced gene regulation for cellular physiology and functions including carcinogenesis. Biochimie 2024; 223:74-97. [PMID: 38723938 DOI: 10.1016/j.biochi.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/08/2024] [Accepted: 05/04/2024] [Indexed: 05/24/2024]
Abstract
Liquid-liquid phase separation (LLPS) describes many biochemical processes, including hydrogel formation, in the integrity of macromolecular assemblages and existence of membraneless organelles, including ribosome, nucleolus, nuclear speckles, paraspeckles, promyelocytic leukemia (PML) bodies, Cajal bodies (all exert crucial roles in cellular physiology), and evidence are emerging day by day. Also, phase separation is well documented in generation of plasma membrane subdomains and interplay between membranous and membraneless organelles. Intrinsically disordered regions (IDRs) of biopolymers/proteins are the most critical sticking regions that aggravate the formation of such condensates. Remarkably, phase separated condensates are also involved in epigenetic regulation of gene expression, chromatin remodeling, and heterochromatinization. Epigenetic marks on DNA and histones cooperate with RNA-binding proteins through their IDRs to trigger LLPS for facilitating transcription. How phase separation coalesces mutant oncoproteins, orchestrate tumor suppressor genes expression, and facilitated cancer-associated signaling pathways are unravelling. That autophagosome formation and DYRK3-mediated cancer stem cell modification also depend on phase separation is deciphered in part. In view of this, and to linchpin insight into the subcellular membraneless organelle assembly, gene activation and biological reactions catalyzed by enzymes, and the downstream physiological functions, and how all these events are precisely facilitated by LLPS inducing organelle function, epigenetic modulation of gene expression in this scenario, and how it goes awry in cancer progression are summarized and presented in this article.
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Affiliation(s)
- Subhajit Chakraborty
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Jagdish Mishra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Niharika
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Soumen Manna
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Piyasa Nandi
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Subhajit Patra
- Department of Chemical Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India.
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4
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Schieweck R, Götz M. Pan-cellular organelles and suborganelles-from common functions to cellular diversity? Genes Dev 2024; 38:98-114. [PMID: 38485267 PMCID: PMC10982711 DOI: 10.1101/gad.351337.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Cell diversification is at the base of increasing multicellular organism complexity in phylogeny achieved during ontogeny. However, there are also functions common to all cells, such as cell division, cell migration, translation, endocytosis, exocytosis, etc. Here we revisit the organelles involved in such common functions, reviewing recent evidence of unexpected differences of proteins at these organelles. For instance, centrosomes or mitochondria differ significantly in their protein composition in different, sometimes closely related, cell types. This has relevance for development and disease. Particularly striking is the high amount and diversity of RNA-binding proteins at these and other organelles, which brings us to review the evidence for RNA at different organelles and suborganelles. We include a discussion about (sub)organelles involved in translation, such as the nucleolus and ribosomes, for which unexpected cell type-specific diversity has also been reported. We propose here that the heterogeneity of these organelles and compartments represents a novel mechanism for regulating cell diversity. One reason is that protein functions can be multiplied by their different contributions in distinct organelles, as also exemplified by proteins with moonlighting function. The specialized organelles still perform pan-cellular functions but in a cell type-specific mode, as discussed here for centrosomes, mitochondria, vesicles, and other organelles. These can serve as regulatory hubs for the storage and transport of specific and functionally important regulators. In this way, they can control cell differentiation, plasticity, and survival. We further include examples highlighting the relevance for disease and propose to examine organelles in many more cell types for their possible differences with functional relevance.
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Affiliation(s)
- Rico Schieweck
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, 38123 Povo, Italy;
- Biomedical Center (BMC), Department of Physiological Genomics, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany
| | - Magdalena Götz
- Biomedical Center (BMC), Department of Physiological Genomics, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany;
- Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, 82152 Planegg-Martinsried, Germany
- SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany
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5
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Shao B, Yan J, Zhang J, Liu L, Chen Y, Buskirk AR. Riboformer: a deep learning framework for predicting context-dependent translation dynamics. Nat Commun 2024; 15:2011. [PMID: 38443396 PMCID: PMC10915169 DOI: 10.1038/s41467-024-46241-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 02/18/2024] [Indexed: 03/07/2024] Open
Abstract
Translation elongation is essential for maintaining cellular proteostasis, and alterations in the translational landscape are associated with a range of diseases. Ribosome profiling allows detailed measurements of translation at the genome scale. However, it remains unclear how to disentangle biological variations from technical artifacts in these data and identify sequence determinants of translation dysregulation. Here we present Riboformer, a deep learning-based framework for modeling context-dependent changes in translation dynamics. Riboformer leverages the transformer architecture to accurately predict ribosome densities at codon resolution. When trained on an unbiased dataset, Riboformer corrects experimental artifacts in previously unseen datasets, which reveals subtle differences in synonymous codon translation and uncovers a bottleneck in translation elongation. Further, we show that Riboformer can be combined with in silico mutagenesis to identify sequence motifs that contribute to ribosome stalling across various biological contexts, including aging and viral infection. Our tool offers a context-aware and interpretable approach for standardizing ribosome profiling datasets and elucidating the regulatory basis of translation kinetics.
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Affiliation(s)
- Bin Shao
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Jiawei Yan
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Jing Zhang
- Biological Design Center, Boston University, Boston, MA, USA
| | - Lili Liu
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Ye Chen
- Key Laboratory of Quantitative Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Allen R Buskirk
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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6
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Di Liegro CM, Schiera G, Schirò G, Di Liegro I. Role of Post-Transcriptional Regulation in Learning and Memory in Mammals. Genes (Basel) 2024; 15:337. [PMID: 38540396 PMCID: PMC10970538 DOI: 10.3390/genes15030337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
After many decades, during which most molecular studies on the regulation of gene expression focused on transcriptional events, it was realized that post-transcriptional control was equally important in order to determine where and when specific proteins were to be synthesized. Translational regulation is of the most importance in the brain, where all the steps of mRNA maturation, transport to different regions of the cells and actual expression, in response to specific signals, constitute the molecular basis for neuronal plasticity and, as a consequence, for structural stabilization/modification of synapses; notably, these latter events are fundamental for the highest brain functions, such as learning and memory, and are characterized by long-term potentiation (LTP) of specific synapses. Here, we will discuss the molecular bases of these fundamental events by considering both the role of RNA-binding proteins (RBPs) and the effects of non-coding RNAs involved in controlling splicing, editing, stability and translation of mRNAs. Importantly, it has also been found that dysregulation of mRNA metabolism/localization is involved in many pathological conditions, arising either during brain development or in the adult nervous system.
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Affiliation(s)
- Carlo Maria Di Liegro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (C.M.D.L.); (G.S.)
| | - Gabriella Schiera
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy; (C.M.D.L.); (G.S.)
| | - Giuseppe Schirò
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
- Neurology and Multiple Sclerosis Center, Unità Operativa Complessa (UOC), Foundation Institute “G. Giglio”, 90015 Cefalù, Italy
| | - Italia Di Liegro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
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7
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Scarpitti MR, Pastore B, Tang W, Kearse MG. Characterization of ribosome stalling and no-go mRNA decay stimulated by the Fragile X protein, FMRP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.577121. [PMID: 38352534 PMCID: PMC10862907 DOI: 10.1101/2024.02.02.577121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Loss of functional fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS) and is the leading monogenic cause of autism spectrum disorders and intellectual disability. FMRP is most notably a translational repressor and is thought to inhibit translation elongation by stalling ribosomes as FMRP-bound polyribosomes from brain tissue are resistant to puromycin and nuclease treatment. Here, we present data showing that the C-terminal non-canonical RNA-binding domain of FMRP is essential and sufficient to induce puromycin-resistant mRNA•ribosome complexes. Given that stalled ribosomes can stimulate ribosome collisions and no-go mRNA decay (NGD), we tested the ability of FMRP to drive NGD of its target transcripts in neuroblastoma cells. Indeed, FMRP and ribosomal proteins, but not PABPC1, were enriched in isolated nuclease-resistant disomes compared to controls. Using siRNA knockdown and RNA-seq, we identified 16 putative FMRP-mediated NGD substrates, many of which encode proteins involved in neuronal development and function. Increased mRNA stability of the putative substrates was also observed when either FMRP was depleted or NGD was prevented via RNAi. Taken together, these data support that FMRP stalls ribosomes and can stimulate NGD of a select set of transcripts in cells, revealing an unappreciated role of FMRP that would be misregulated in FXS.
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8
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Popper B, Bürkle M, Ciccopiedi G, Marchioretto M, Forné I, Imhof A, Straub T, Viero G, Götz M, Schieweck R. Ribosome inactivation regulates translation elongation in neurons. J Biol Chem 2024; 300:105648. [PMID: 38219816 PMCID: PMC10869266 DOI: 10.1016/j.jbc.2024.105648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/10/2023] [Accepted: 01/02/2024] [Indexed: 01/16/2024] Open
Abstract
Cellular plasticity is crucial for adapting to ever-changing stimuli. As a result, cells consistently reshape their translatome, and, consequently, their proteome. The control of translational activity has been thoroughly examined at the stage of translation initiation. However, the regulation of ribosome speed in cells is widely unknown. In this study, we utilized a timed ribosome runoff approach, along with proteomics and transmission electron microscopy, to investigate global translation kinetics in cells. We found that ribosome speeds vary among various cell types, such as astrocytes, induced pluripotent human stem cells, human neural stem cells, and human and rat neurons. Of all cell types studied, mature cortical neurons exhibit the highest rate of translation. This finding is particularly remarkable because mature cortical neurons express the eukaryotic elongation factor 2 (eEF2) at lower levels than other cell types. Neurons solve this conundrum by inactivating a fraction of their ribosomes. As a result, the increase in eEF2 levels leads to a reduction of inactive ribosomes and an enhancement of active ones. Processes that alter the demand for active ribosomes, like neuronal excitation, cause increased inactivation of redundant ribosomes in an eEF2-dependent manner. Our data suggest a novel regulatory mechanism in which neurons dynamically inactivate ribosomes to facilitate translational remodeling. These findings have important implications for developmental brain disorders characterized by, among other things, aberrant translation.
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Affiliation(s)
- Bastian Popper
- Core Facility Animal Models, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Martina Bürkle
- Department of Physiological Genomics, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Giuliana Ciccopiedi
- Department for Cell Biology & Anatomy, Biomedical Center (BMC), LMU Munich, Munich, Germany; Graduate School of Systemic Neurosciences, LMU Munich, Munich, Germany
| | - Marta Marchioretto
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, Povo, Italy
| | - Ignasi Forné
- Protein Analysis Unit, Department for Molecular Biology, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Axel Imhof
- Protein Analysis Unit, Department for Molecular Biology, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Tobias Straub
- Bioinformatics Core Facility, Department of Molecular Biology, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Gabriella Viero
- Institute of Biophysics, National Research Council (CNR) Unit at Trento, Povo, Italy
| | - Magdalena Götz
- Department of Physiological Genomics, Biomedical Center (BMC), LMU Munich, Munich, Germany; Institute of Stem Cell Research, Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany; SYNERGY, Excellence Cluster of Systems Neurology, Biomedical Center (BMC), LMU Munich, Munich, Germany
| | - Rico Schieweck
- Department of Physiological Genomics, Biomedical Center (BMC), LMU Munich, Munich, Germany; Department for Cell Biology & Anatomy, Biomedical Center (BMC), LMU Munich, Munich, Germany; Institute of Biophysics, National Research Council (CNR) Unit at Trento, Povo, Italy.
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9
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Kaul N, Pradhan SJ, Boin NG, Mason MM, Rosales J, Starke EL, Wilkinson EC, Chapman EG, Barbee SA. FMRP cooperates with miRISC components to repress translation and regulate neurite morphogenesis in Drosophila. RNA Biol 2024; 21:11-22. [PMID: 39190491 PMCID: PMC11352701 DOI: 10.1080/15476286.2024.2392304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/29/2024] [Accepted: 08/06/2024] [Indexed: 08/29/2024] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited form of intellectual disability and is caused by mutations in the gene encoding the Fragile X messenger ribonucleoprotein (FMRP). FMRP is an evolutionarily conserved and neuronally enriched RNA-binding protein (RBP) with functions in RNA editing, RNA transport, and protein translation. Specific target RNAs play critical roles in neurodevelopment, including the regulation of neurite morphogenesis, synaptic plasticity, and cognitive function. The different biological functions of FMRP are modulated by its cooperative interaction with distinct sets of neuronal RNA and protein-binding partners. Here, we focus on interactions between FMRP and components of the microRNA (miRNA) pathway. Using the Drosophila S2 cell model system, we show that the Drosophila ortholog of FMRP (dFMRP) can repress translation when directly tethered to a reporter mRNA. This repression requires the activity of AGO1, GW182, and MOV10/Armitage, conserved proteins associated with the miRNA-containing RNA-induced silencing complex (miRISC). Additionally, we find that untagged dFMRP can interact with a short stem-loop sequence in the translational reporter, a prerequisite for repression by exogenous miR-958. Finally, we demonstrate that dFmr1 interacts genetically with GW182 to control neurite morphogenesis. These data suggest that dFMRP may recruit the miRISC to nearby miRNA binding sites and repress translation via its cooperative interactions with evolutionarily conserved components of the miRNA pathway.
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Affiliation(s)
- Navneeta Kaul
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Sarala J. Pradhan
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Nathan G. Boin
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Madeleine M. Mason
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Julian Rosales
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, USA
| | - Emily L. Starke
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Emily C. Wilkinson
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Erich G. Chapman
- Department of Biological Sciences, University of Denver, Denver, CO, USA
- Department of Chemistry and Biochemistry, University of Denver, Denver, CO, USA
- Molecular and Cellular Biophysics Program, University of Denver, Denver, CO, USA
| | - Scott A. Barbee
- Department of Biological Sciences, University of Denver, Denver, CO, USA
- Molecular and Cellular Biophysics Program, University of Denver, Denver, CO, USA
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10
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Susanto TT, Hung V, Levine AG, Kerr CH, Yoo Y, Chen Y, Oses-Prieto JA, Fromm L, Fujii K, Wernig M, Burlingame AL, Ruggero D, Barna M. RAPIDASH: A tag-free enrichment of ribosome-associated proteins reveals compositional dynamics in embryonic tissues and stimulated macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.07.570613. [PMID: 38106052 PMCID: PMC10723405 DOI: 10.1101/2023.12.07.570613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Ribosomes are emerging as direct regulators of gene expression, with ribosome-associated proteins (RAPs) allowing ribosomes to modulate translational control. However, a lack of technologies to enrich RAPs across many sample types has prevented systematic analysis of RAP number, dynamics, and functions. Here, we have developed a label-free methodology called RAPIDASH to enrich ribosomes and RAPs from any sample. We applied RAPIDASH to mouse embryonic tissues and identified hundreds of potential RAPs, including DHX30 and LLPH, two forebrain RAPs important for neurodevelopment. We identified a critical role of LLPH in neural development that is linked to the translation of genes with long coding sequences. Finally, we characterized ribosome composition remodeling during immune activation and observed extensive changes post-stimulation. RAPIDASH has therefore enabled the discovery of RAPs ranging from those with neuroregulatory functions to those activated by immune stimuli, thereby providing critical insights into how ribosomes are remodeled.
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Affiliation(s)
- Teodorus Theo Susanto
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Victoria Hung
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew G Levine
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Craig H Kerr
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yongjin Yoo
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yuxiang Chen
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Lisa Fromm
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
| | - Kotaro Fujii
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Davide Ruggero
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA
| | - Maria Barna
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
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11
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Jung S, Shah S, Han G, Richter JD. FMRP deficiency leads to multifactorial dysregulation of splicing and mislocalization of MBNL1 to the cytoplasm. PLoS Biol 2023; 21:e3002417. [PMID: 38048343 PMCID: PMC10721184 DOI: 10.1371/journal.pbio.3002417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 12/14/2023] [Accepted: 11/03/2023] [Indexed: 12/06/2023] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that is often modeled in Fmr1 knockout mice where the RNA-binding protein FMRP is absent. Here, we show that in Fmr1-deficient mice, RNA mis-splicing occurs in several brain regions and peripheral tissues. To assess molecular mechanisms of splicing mis-regulation, we employed N2A cells depleted of Fmr1. In the absence of FMRP, RNA-specific exon skipping events are linked to the splicing factors hnRNPF, PTBP1, and MBNL1. FMRP regulates the translation of Mbnl1 mRNA as well as Mbnl1 RNA auto-splicing. Elevated Mbnl1 auto-splicing in FMRP-deficient cells results in the loss of a nuclear localization signal (NLS)-containing exon. This in turn alters the nucleus-to-cytoplasm ratio of MBNL1. This redistribution of MBNL1 isoforms in Fmr1-deficient cells could result in downstream splicing changes in other RNAs. Indeed, further investigation revealed that splicing disruptions resulting from Fmr1 depletion could be rescued by overexpression of nuclear MBNL1. Altered Mbnl1 auto-splicing also occurs in human FXS postmortem brain. These data suggest that FMRP-controlled translation and RNA processing may cascade into a general dys-regulation of splicing in Fmr1-deficient cells.
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Affiliation(s)
- Suna Jung
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Sneha Shah
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Geongoo Han
- Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Joel D. Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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12
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Liu B, Luo L, Shi Z, Ju H, Yu L, Li G, Cui J. Research Progress of Porcine Reproductive and Respiratory Syndrome Virus NSP2 Protein. Viruses 2023; 15:2310. [PMID: 38140551 PMCID: PMC10747760 DOI: 10.3390/v15122310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is globally prevalent and seriously harms the economic efficiency of pig farming. Because of its immunosuppression and high incidence of mutant recombination, PRRSV poses a great challenge for disease prevention and control. Nonstructural protein 2 (NSP2) is the most variable functional protein in the PRRSV genome and can generate NSP2N and NSP2TF variants due to programmed ribosomal frameshifts. These variants are broad and complex in function and play key roles in numerous aspects of viral protein maturation, viral particle assembly, regulation of immunity, autophagy, apoptosis, cell cycle and cell morphology. In this paper, we review the structural composition, programmed ribosomal frameshift and biological properties of NSP2 to facilitate basic research on PRRSV and to provide theoretical support for disease prevention and control and therapeutic drug development.
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Affiliation(s)
- Benjin Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150038, China; (B.L.); (L.L.); (Z.S.)
| | - Lingzhi Luo
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150038, China; (B.L.); (L.L.); (Z.S.)
| | - Ziqi Shi
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150038, China; (B.L.); (L.L.); (Z.S.)
| | - Houbin Ju
- Shanghai Animal Disease Prevention and Control Center, Shanghai 201103, China;
| | - Lingxue Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China;
| | - Guoxin Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China;
| | - Jin Cui
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150038, China; (B.L.); (L.L.); (Z.S.)
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13
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Kharod SC, Hwang DW, Choi H, Yoon KJ, Castillo PE, Singer RH, Yoon YJ. Phosphorylation alters FMRP granules and determines their transport or protein synthesis abilities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532613. [PMID: 37781583 PMCID: PMC10541110 DOI: 10.1101/2023.03.15.532613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Fragile X messenger ribonucleoprotein (FMRP) is an RNA-binding protein implicated in autism that suppresses translation and forms granules. While FMRP function has been well-studied, how phosphorylation regulates granule binding and function remains limited. Here, we found that Fragile X patient-derived I304N mutant FMRP could not stably bind granules, underscoring the essential nature of FMRP granule association for function. Next, phosphorylation on serine 499 (S499) led to differences in puncta size, intensity, contrast, and transport as shown by phospho-deficient (S499A) and phospho-mimic (S499D) mutant FMRP granules. Additionally, S499D exchanged slowly on granules relative to S499A, suggesting that phosphorylated FMRP can attenuate translation. Furthermore, the S499A mutant enhanced translation in presynaptic boutons of the mouse hippocampus. Thus, the phospho-state of FMRP altered the structure of individual granules with changes in transport and translation to achieve spatiotemporal regulation of local protein synthesis. Teaser The phosphorylation-state of S499 on FMRP can change FMRP granule structure and function to facilitate processive transport or local protein synthesis.
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14
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Yu J, Woo Y, Kim H, An S, Park SK, Jang SK. FMRP Enhances the Translation of 4EBP2 mRNA during Neuronal Differentiation. Int J Mol Sci 2023; 24:16319. [PMID: 38003508 PMCID: PMC10671300 DOI: 10.3390/ijms242216319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/08/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
FMRP is a multifunctional protein encoded by the Fragile X Messenger Ribonucleoprotein 1 gene (FMR1). The inactivation of the FMR1 gene results in fragile X syndrome (FXS), a serious neurodevelopmental disorder. FMRP deficiency causes abnormal neurite outgrowth, which is likely to lead to abnormal learning and memory capabilities. However, the mechanism of FMRP in modulating neuronal development remains unknown. We found that FMRP enhances the translation of 4EBP2, a neuron-specific form of 4EBPs that inactivates eIF4E by inhibiting the interaction between eIF4E and eIF4G. Depletion of 4EBP2 results in abnormal neurite outgrowth. Moreover, the impairment of neurite outgrowth upon FMRP depletion was overcome by the ectopic expression of 4EBP2. These results suggest that FMRP controls neuronal development by enhancing 4EBP2 expression at the translational level. In addition, treatment with 4EGI-1, a chemical that blocks eIF4E activity, restored neurite length in FMRP-depleted and 4EBP2-depleted cells. In conclusion, we discovered that 4EBP2 functions as a key downstream regulator of FMRP activity in neuronal development and that FMRP represses eIF4E activity by enhancing 4EBP2 translation.
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Affiliation(s)
| | | | | | | | - Sang Ki Park
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Gyeongsangbuk, Republic of Korea; (J.Y.); (Y.W.); (H.K.); (S.A.)
| | - Sung Key Jang
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 37673, Gyeongsangbuk, Republic of Korea; (J.Y.); (Y.W.); (H.K.); (S.A.)
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15
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Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
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Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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16
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Häfner SJ, Jansson MD, Altinel K, Andersen KL, Abay-Nørgaard Z, Ménard P, Fontenas M, Sørensen DM, Gay DM, Arendrup FS, Tehler D, Krogh N, Nielsen H, Kraushar ML, Kirkeby A, Lund AH. Ribosomal RNA 2'-O-methylation dynamics impact cell fate decisions. Dev Cell 2023; 58:1593-1609.e9. [PMID: 37473757 DOI: 10.1016/j.devcel.2023.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 02/16/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023]
Abstract
Translational regulation impacts both pluripotency maintenance and cell differentiation. To what degree the ribosome exerts control over this process remains unanswered. Accumulating evidence has demonstrated heterogeneity in ribosome composition in various organisms. 2'-O-methylation (2'-O-me) of rRNA represents an important source of heterogeneity, where site-specific alteration of methylation levels can modulate translation. Here, we examine changes in rRNA 2'-O-me during mouse brain development and tri-lineage differentiation of human embryonic stem cells (hESCs). We find distinct alterations between brain regions, as well as clear dynamics during cortex development and germ layer differentiation. We identify a methylation site impacting neuronal differentiation. Modulation of its methylation levels affects ribosome association of the fragile X mental retardation protein (FMRP) and is accompanied by an altered translation of WNT pathway-related mRNAs. Together, these data identify ribosome heterogeneity through rRNA 2'-O-me during early development and differentiation and suggest a direct role for ribosomes in regulating translation during cell fate acquisition.
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Affiliation(s)
- Sophia J Häfner
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Martin D Jansson
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kübra Altinel
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kasper L Andersen
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Zehra Abay-Nørgaard
- Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW) and Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Patrice Ménard
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Martin Fontenas
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Daniel M Sørensen
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - David M Gay
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Frederic S Arendrup
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Disa Tehler
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolai Krogh
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | | | - Agnete Kirkeby
- Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW) and Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, 2200 Copenhagen, Denmark; Wallenberg Center for Molecular Medicine, Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden
| | - Anders H Lund
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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17
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Winden KD, Pham TT, Teaney NA, Ruiz J, Chen R, Chen C, Sahin M. Increased degradation of FMRP contributes to neuronal hyperexcitability in tuberous sclerosis complex. Cell Rep 2023; 42:112838. [PMID: 37494191 PMCID: PMC10529098 DOI: 10.1016/j.celrep.2023.112838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/12/2023] [Accepted: 07/05/2023] [Indexed: 07/28/2023] Open
Abstract
Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder, but new therapies have been impeded by a lack of understanding of the pathological mechanisms. Tuberous sclerosis complex (TSC) and fragile X syndrome are associated with alterations in the mechanistic target of rapamycin (mTOR) and fragile X messenger ribonucleoprotein 1 (FMRP), which have been implicated in the development of ASD. Previously, we observed that transcripts associated with FMRP were down-regulated in TSC2-deficient neurons. In this study, we find that FMRP turnover is dysregulated in TSC2-deficient rodent primary neurons and human induced pluripotent stem cell (iPSC)-derived neurons and is dependent on the E3 ubiquitin ligase anaphase-promoting complex. We also demonstrate that overexpression of FMRP can partially rescue hyperexcitability in TSC2-deficient iPSC-derived neurons. These data indicate that FMRP dysregulation represents an important pathological mechanism in the development of abnormal neuronal activity in TSC and illustrate a molecular convergence between these two neurogenetic disorders.
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Affiliation(s)
- Kellen D Winden
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Truc T Pham
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicole A Teaney
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Juan Ruiz
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ryan Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Cidi Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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18
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Chaves-Arquero B, Collins KM, Abis G, Kelly G, Christodoulou E, Taylor IA, Ramos A. Affinity-enhanced RNA-binding domains as tools to understand RNA recognition. CELL REPORTS METHODS 2023; 3:100508. [PMID: 37426752 PMCID: PMC10326445 DOI: 10.1016/j.crmeth.2023.100508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 03/14/2023] [Accepted: 05/30/2023] [Indexed: 07/11/2023]
Abstract
Understanding how the RNA-binding domains of a protein regulator are used to recognize its RNA targets is a key problem in RNA biology, but RNA-binding domains with very low affinity do not perform well in the methods currently available to characterize protein-RNA interactions. Here, we propose to use conservative mutations that enhance the affinity of RNA-binding domains to overcome this limitation. As a proof of principle, we have designed and validated an affinity-enhanced K-homology (KH) domain mutant of the fragile X syndrome protein FMRP, a key regulator of neuronal development, and used this mutant to determine the domain's sequence preference and to explain FMRP recognition of specific RNA motifs in the cell. Our results validate our concept and our nuclear magnetic resonance (NMR)-based workflow. While effective mutant design requires an understanding of the underlying principles of RNA recognition by the relevant domain type, we expect the method will be used effectively in many RNA-binding domains.
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Affiliation(s)
- Belén Chaves-Arquero
- Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6AA, UK
- Department of Structural and Chemical Biology, Center for Biological Research, CIB, CSIC, Av. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Katherine M. Collins
- Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6AA, UK
| | - Giancarlo Abis
- Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6AA, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Evangelos Christodoulou
- Structural Biology Science Technology Platform, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Ian A. Taylor
- Macromolecular Structure Laboratory, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Andres Ramos
- Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6AA, UK
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19
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Chowdhury MN, Chen X, Jin H. An intrinsically Disordered RNA Binding Protein Modulates mRNA Translation and Storage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541713. [PMID: 37293096 PMCID: PMC10245857 DOI: 10.1101/2023.05.22.541713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Many proteins with intrinsically disordered regions interact with cytoplasmic ribosomes. However, many of the molecular functions related to these interactions are unclear. In this study, using an abundant RNA-binding protein with a structurally well-defined RNA recognition motif and an intrinsically disordered RGG domain as a model system, we investigated how this protein modulates mRNA storage and translation. Using genomic and molecular approaches, we show that the presence of Sbp1 slows ribosome movement on cellular mRNAs and promotes polysome stalling. Sbp1-associated polysomes display a ring-shaped structure in addition to a beads-on-string morphology visualized under electron microscope. Moreover, post-translational modifications at the RGG motif play important roles in directing cellular mRNAs to either translation or storage. Finally, binding of Sbp1 to the 5'UTRs of mRNAs represses both cap-dependent and cap-independent translation initiation of proteins functionally important for general protein synthesis in the cell. Taken together, our study demonstrates an intrinsically disordered RNA binding protein regulates mRNA translation and storage via distinctive mechanisms under physiological conditions and establishes a framework with which functions of important RGG-proteins can be investigated and defined.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Xin Chen
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
- Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
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20
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Shao B, Yan J, Zhang J, Buskirk AR. Riboformer: A Deep Learning Framework for Predicting Context-Dependent Translation Dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538053. [PMID: 37163112 PMCID: PMC10168224 DOI: 10.1101/2023.04.24.538053] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Translation elongation is essential for maintaining cellular proteostasis, and alterations in the translational landscape are associated with a range of diseases. Ribosome profiling allows detailed measurement of translation at genome scale. However, it remains unclear how to disentangle biological variations from technical artifacts and identify sequence determinant of translation dysregulation. Here we present Riboformer, a deep learning-based framework for modeling context-dependent changes in translation dynamics. Riboformer leverages the transformer architecture to accurately predict ribosome densities at codon resolution. It corrects experimental artifacts in previously unseen datasets, reveals subtle differences in synonymous codon translation and uncovers a bottleneck in protein synthesis. Further, we show that Riboformer can be combined with in silico mutagenesis analysis to identify sequence motifs that contribute to ribosome stalling across various biological contexts, including aging and viral infection. Our tool offers a context-aware and interpretable approach for standardizing ribosome profiling datasets and elucidating the regulatory basis of translation kinetics.
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Affiliation(s)
- Bin Shao
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Present address: Klarman Cell Observatory, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Jiawei Yan
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Jing Zhang
- Biological Design Center, Boston University, Boston, MA, USA
| | - Allen R. Buskirk
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
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21
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Tang X, Zhang J, Li X, Hu Y, Liu D, Li JD, Lu R. FMRP binds Per1 mRNA and downregulates its protein expression in mice. Mol Brain 2023; 16:33. [PMID: 37020302 PMCID: PMC10077598 DOI: 10.1186/s13041-023-01023-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/24/2023] [Indexed: 04/07/2023] Open
Abstract
FMRP, an RNA-binding protein, has previously shown to be involved in regulation of circadian rhythms in flies and mice. However, the molecular mechanism remains elusive. Here we demonstrate that core circadian component Per1 mRNA was a target of FMRP and the association leads to reduced PER1 expression. In Fmr1 KO mice, the oscillation of PER1 protein expression was significantly affected in a temporal and tissue-dependent pattern when compared to WT mice. Our work thus identified Per1 mRNA as a novel target of FMRP and suggested a potential role of FMRP in regulation of circadian function.
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Affiliation(s)
- Xiangrong Tang
- Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China
- Center for Reproductive Medicine, Women and Children's Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Jing Zhang
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China
| | - Xin Li
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China
| | - Ying Hu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China
| | - Dengfeng Liu
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China
| | - Jia-Da Li
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China.
- National Clinical Research Center for Geratric Disorder, Xiangya Hospital, Central South University, Changsha, 410008, China.
| | - Renbin Lu
- Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China.
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, 410078, Hunan, China.
- National Clinical Research Center for Geratric Disorder, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Department of Basic Medical Sciences, Changsha Medical University, Changsha, China.
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22
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Anadolu MN, Sun J, Kailasam S, Chalkiadaki K, Krimbacher K, Li JTY, Markova T, Jafarnejad SM, Lefebvre F, Ortega J, Gkogkas CG, Sossin WS. Ribosomes in RNA Granules Are Stalled on mRNA Sequences That Are Consensus Sites for FMRP Association. J Neurosci 2023; 43:2440-2459. [PMID: 36849416 PMCID: PMC10082463 DOI: 10.1523/jneurosci.1002-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 03/01/2023] Open
Abstract
Local translation in neurons is partly mediated by the reactivation of stalled polysomes. Stalled polysomes may be enriched within the granule fraction, defined as the pellet of sucrose gradients used to separate polysomes from monosomes. The mechanism of how elongating ribosomes are reversibly stalled and unstalled on mRNAs is still unclear. In the present study, we characterize the ribosomes in the granule fraction using immunoblotting, cryogenic electron microscopy (cryo-EM), and ribosome profiling. We find that this fraction, isolated from 5-d-old rat brains of both sexes, is enriched in proteins implicated in stalled polysome function, such as the fragile X mental retardation protein (FMRP) and Up-frameshift mutation 1 homologue. Cryo-EM analysis of ribosomes in this fraction indicates they are stalled, mainly in the hybrid state. Ribosome profiling of this fraction reveals (1) an enrichment for footprint reads of mRNAs that interact with FMRPs and are associated with stalled polysomes, (2) an abundance of footprint reads derived from mRNAs of cytoskeletal proteins implicated in neuronal development, and (3) increased ribosome occupancy on mRNAs encoding RNA binding proteins. Compared with those usually found in ribosome profiling studies, the footprint reads were longer and were mapped to reproducible peaks in the mRNAs. These peaks were enriched in motifs previously associated with mRNAs cross-linked to FMRP in vivo, independently linking the ribosomes in the granule fraction to the ribosomes associated with FMRP in the cell. The data supports a model in which specific sequences in mRNAs act to stall ribosomes during translation elongation in neurons.SIGNIFICANCE STATEMENT Neurons send mRNAs to synapses in RNA granules, where they are not translated until an appropriate stimulus is given. Here, we characterize a granule fraction obtained from sucrose gradients and show that polysomes in this fraction are stalled on consensus sequences in a specific state of translational arrest with extended ribosome-protected fragments. This finding greatly increases our understanding of how neurons use specialized mechanisms to regulate translation and suggests that many studies on neuronal translation may need to be re-evaluated to include the large fraction of neuronal polysomes found in the pellet of sucrose gradients used to isolate polysomes.
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Affiliation(s)
- Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Jingyu Sun
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Senthilkumar Kailasam
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Kleanthi Chalkiadaki
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Konstanze Krimbacher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck Austria Division of Biomedical Research, A-6020 Innsbruck, Austria
| | - Jewel T-Y Li
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Teodora Markova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Seyed M Jafarnejad
- Patrick G, Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland BT9 7AE, United Kingdom
| | - Francois Lefebvre
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Christos G Gkogkas
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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23
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Miller SC, MacDonald CC, Kellogg MK, Karamysheva ZN, Karamyshev AL. Specialized Ribosomes in Health and Disease. Int J Mol Sci 2023; 24:ijms24076334. [PMID: 37047306 PMCID: PMC10093926 DOI: 10.3390/ijms24076334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023] Open
Abstract
Ribosomal heterogeneity exists within cells and between different cell types, at specific developmental stages, and occurs in response to environmental stimuli. Mounting evidence supports the existence of specialized ribosomes, or specific changes to the ribosome that regulate the translation of a specific group of transcripts. These alterations have been shown to affect the affinity of ribosomes for certain mRNAs or change the cotranslational folding of nascent polypeptides at the exit tunnel. The identification of specialized ribosomes requires evidence of the incorporation of different ribosomal proteins or of modifications to rRNA and/or protein that lead(s) to physiologically relevant changes in translation. In this review, we summarize ribosomal heterogeneity and specialization in mammals and discuss their relevance to several human diseases.
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Affiliation(s)
- Sarah C. Miller
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Clinton C. MacDonald
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Morgana K. Kellogg
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | | | - Andrey L. Karamyshev
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
- Correspondence: ; Tel.: +1-806-743-4102
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24
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Serine 970 of RNA helicase MOV10 is phosphorylated and controls unfolding activity and fate of mRNAs targeted for AGO2-mediated silencing. J Biol Chem 2023; 299:104577. [PMID: 36871759 PMCID: PMC10070924 DOI: 10.1016/j.jbc.2023.104577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/07/2023] Open
Abstract
MOV10 is an RNA helicase that is required for organismal development and is highly expressed in postnatal brain. MOV10 was identified as an AGO2 associated protein that is also necessary for AGO2-mediated silencing. AGO2 is the primary effector of the miRNA pathway. MOV10 has been shown to be ubiquitinated, leading to its degradation and release from bound mRNAs but no other post-translational modifications with functional implications have been described. Using mass spectrometry, we show that MOV10 is phosphorylated in cells at the C-terminus, specifically at serine 970 (S970). Substitution of S970 to phospho-mimic aspartic acid (S970D) blocked unfolding of an RNA G-quadruplex, similar to when the helicase domain was mutated (K531A). In contrast, the alanine substitution (S970A) of MOV10 unfolded the model RNA G-quadruplex. To examine its role in cells, our RNA-seq analysis showed that the expression of S970D causes decreased expression of MOV10 enhanced Cross-Linking Immunoprecipitation (eCLIP) targets compared to WT. Introduction of S970A had an intermediate effect, suggesting that S970 was protective of mRNAs. In whole cell extracts, MOV10 and its substitutions bound AGO2 comparably; however, knockdown of AGO2 abrogated the S970D-induced mRNA degradation. Thus, MOV10 activity protects mRNA from AGO2; phosphorylation of S970 restricts this activity resulting in AGO2-mediated mRNA degradation. S970 is positioned C-terminal to the defined MOV10-AGO2 interaction site and is proximal to a disordered region that likely modulates AGO2 interaction with target mRNAs upon phosphorylation. In summary, we provide evidence for a model whereby MOV10 phosphorylation facilitates AGO2 association with the 3'UTR of translating mRNAs that leads to their degradation.
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25
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Anreiter I, Tian YW, Soller M. The cap epitranscriptome: Early directions to a complex life as mRNA. Bioessays 2023; 45:e2200198. [PMID: 36529693 DOI: 10.1002/bies.202200198] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022]
Abstract
Animal, protist and viral messenger RNAs (mRNAs) are most prominently modified at the beginning by methylation of cap-adjacent nucleotides at the 2'-O-position of the ribose (cOMe) by dedicated cap methyltransferases (CMTrs). If the first nucleotide of an mRNA is an adenosine, PCIF1 can methylate at the N6 -position (m6 A), while internally the Mettl3/14 writer complex can methylate. These modifications are introduced co-transcriptionally to affect many aspects of gene expression including localisation to synapses and local translation. Of particular interest, transcription start sites of many genes are heterogeneous leading to sequence diversity at the beginning of mRNAs, which together with cOMe and m6 Am could constitute an extensive novel layer of gene expression control. Given the role of cOMe and m6 A in local gene expression at synapses and higher brain functions including learning and memory, such code could be implemented at the transcriptional level for lasting memories through local gene expression at synapses.
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Affiliation(s)
- Ina Anreiter
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| | - Yuan W Tian
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK.,School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Matthias Soller
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, UK.,School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
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26
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Abstract
The fragile X-related disorders are an important group of hereditary disorders that are caused by expanded CGG repeats in the 5' untranslated region of the FMR1 gene or by mutations in the coding sequence of this gene. Two categories of pathological CGG repeats are associated with these disorders, full mutation alleles and shorter premutation alleles. Individuals with full mutation alleles develop fragile X syndrome, which causes autism and intellectual disability, whereas those with premutation alleles, which have shorter CGG expansions, can develop fragile X-associated tremor/ataxia syndrome, a progressive neurodegenerative disease. Thus, fragile X-related disorders can manifest as neurodegenerative or neurodevelopmental disorders, depending on the size of the repeat expansion. Here, we review mouse models of fragile X-related disorders and discuss how they have informed our understanding of neurodegenerative and neurodevelopmental disorders. We also assess the translational value of these models for developing rational targeted therapies for intellectual disability and autism disorders.
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Affiliation(s)
- Rob Willemsen
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
| | - R. Frank Kooy
- Department of Clinical Genetics, Erasmus University Medical Center, 3015 CN Rotterdam, the Netherlands. Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium
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27
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Webster SF, Ghalei H. Maturation of small nucleolar RNAs: from production to function. RNA Biol 2023; 20:715-736. [PMID: 37796118 PMCID: PMC10557570 DOI: 10.1080/15476286.2023.2254540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Small Nucleolar RNAs (snoRNAs) are an abundant group of non-coding RNAs with well-defined roles in ribosomal RNA processing, folding and chemical modification. Besides their classic roles in ribosome biogenesis, snoRNAs are also implicated in several other cellular activities including regulation of splicing, transcription, RNA editing, cellular trafficking, and miRNA-like functions. Mature snoRNAs must undergo a series of processing steps tightly regulated by transiently associating factors and coordinated with other cellular processes including transcription and splicing. In addition to their mature forms, snoRNAs can contribute to gene expression regulation through their derivatives and degradation products. Here, we review the current knowledge on mechanisms of snoRNA maturation, including the different pathways of processing, and the regulatory mechanisms that control snoRNA levels and complex assembly. We also discuss the significance of studying snoRNA maturation, highlight the gaps in the current knowledge and suggest directions for future research in this area.
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Affiliation(s)
- Sarah F. Webster
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia, USA
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
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28
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Chowdhury MN, Jin H. The RGG motif proteins: Interactions, functions, and regulations. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1748. [PMID: 35661420 PMCID: PMC9718894 DOI: 10.1002/wrna.1748] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 01/31/2023]
Abstract
Proteins with motifs rich in arginines and glycines were discovered decades ago and are functionally involved in a staggering range of essential processes in the cell. Versatile, specific, yet adaptable molecular interactions enabled by the unique combination of arginine and glycine, combined with multiplicity of molecular recognition conferred by repeated di-, tri-, and multiple peptide motifs, allow RGG motif proteins to interact with a broad range of proteins and nucleic acids. Furthermore, posttranslational modifications at the arginines in the motif extend the RGG protein's capacity for a fine-tuned regulation. In this review, we focus on the biochemical properties of the RGG motif, its molecular interactions with RNAs and proteins, and roles of the posttranslational modification in modulating their interactions. We discuss current knowledge of the RGG motif proteins involved in mRNA transport and translation, highlight our merging understanding of their molecular functions in translational regulation and summarize areas of research in the future critical in understanding this important family of proteins. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Mechanisms.
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Affiliation(s)
- Mashiat N. Chowdhury
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801
| | - Hong Jin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Carl R. Woese Institute for Genomic Biology, 1206 West Gregory Drive, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801,Corresponding author: Phone: (217)244-9493, Fax: (217)244-5858,
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29
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Kurosaki T, Mitsutomi S, Hewko A, Akimitsu N, Maquat LE. Integrative omics indicate FMRP sequesters mRNA from translation and deadenylation in human neuronal cells. Mol Cell 2022; 82:4564-4581.e11. [PMID: 36356584 PMCID: PMC9753132 DOI: 10.1016/j.molcel.2022.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 11/10/2022]
Abstract
How fragile X syndrome protein (FMRP) binds mRNAs and regulates mRNA metabolism remains unclear. Our previous work using human neuronal cells focused on mRNAs targeted for nonsense-mediated mRNA decay (NMD), which we showed are generally bound by FMRP and destabilized upon FMRP loss. Here, we identify >400 high-confidence FMRP-bound mRNAs, only ∼35% of which are NMD targets. Integrative transcriptomics together with SILAC-LC-MS/MS reveal that FMRP loss generally results in mRNA destabilization and more protein produced per FMRP target. We use our established RIP-seq technology to show that FMRP footprints are independent of protein-coding potential, target GC-rich and structured sequences, and are densest in 5' UTRs. Regardless of where within an mRNA FMRP binds, we find that FMRP protects mRNAs from deadenylation and directly binds the cytoplasmic poly(A)-binding protein. Our results reveal how FMRP sequesters polyadenylated mRNAs into stabilized and translationally repressed complexes, whose regulation is critical for neurogenesis and synaptic plasticity.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
| | - Shuhei Mitsutomi
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA; Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Alexander Hewko
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Nobuyoshi Akimitsu
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
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30
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Scarpitti MR, Warrick JE, Yoder EL, Kearse MG. A noncanonical RNA-binding domain of the fragile X protein, FMRP, elicits translational repression independent of mRNA G-quadruplexes. J Biol Chem 2022; 298:102660. [PMID: 36328245 PMCID: PMC9712993 DOI: 10.1016/j.jbc.2022.102660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/12/2022] [Accepted: 10/21/2022] [Indexed: 11/07/2022] Open
Abstract
Loss of functional fragile X mental retardation protein (FMRP) causes fragile X syndrome, the leading form of inherited intellectual disability and the most common monogenic cause of autism spectrum disorders. FMRP is an RNA-binding protein that controls neuronal mRNA localization and translation. FMRP is thought to inhibit translation elongation after being recruited to target transcripts via binding RNA G-quadruplexes (G4s) within the coding sequence. Here, we directly test this model and report that FMRP inhibits translation independent of mRNA G4s. Furthermore, we found that the RGG box motif together with its natural C-terminal domain forms a noncanonical RNA-binding domain (ncRBD) that is essential for translational repression. The ncRBD elicits broad RNA-binding ability and binds to multiple reporter mRNAs and all four homopolymeric RNAs. Serial deletion analysis of the ncRBD identified that the regions required for mRNA binding and translational repression overlap but are not identical. Consistent with FMRP stalling elongating ribosomes and causing the accumulation of slowed 80S ribosomes, transcripts bound by FMRP via the ncRBD cosediment with heavier polysomes and were present in puromycin-resistant ribosome complexes. Together, this work identifies a ncRBD and translational repression domain that shifts our understanding of how FMRP inhibits translation independent of mRNA G4s.
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Affiliation(s)
- MaKenzie R Scarpitti
- The Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Julia E Warrick
- The Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Evelyn L Yoder
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Michael G Kearse
- The Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, USA; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
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31
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D'Souza MN, Ramakrishna S, Radhakrishna BK, Jhaveri V, Ravindran S, Yeramala L, Nair D, Palakodeti D, Muddashetty RS. Function of FMRP Domains in Regulating Distinct Roles of Neuronal Protein Synthesis. Mol Neurobiol 2022; 59:7370-7392. [PMID: 36181660 DOI: 10.1007/s12035-022-03049-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 09/09/2022] [Indexed: 11/24/2022]
Abstract
The Fragile-X Mental Retardation Protein (FMRP) is an RNA binding protein that regulates translation of mRNAs essential for synaptic development and plasticity. FMRP interacts with a specific set of mRNAs, aids in their microtubule-dependent transport and regulates their translation through its association with ribosomes. However, the biochemical role of FMRP's domains in forming neuronal granules and associating with microtubules and ribosomes is currently undefined. We report that the C-terminus domain of FMRP is sufficient to bind to ribosomes akin to the full-length protein. Furthermore, the C-terminus domain alone is essential and responsible for FMRP-mediated neuronal translation repression. However, dendritic distribution of FMRP and its microtubule association is favored by the synergistic combination of FMRP domains rather than individual domains. Interestingly, we show that the phosphorylation of hFMRP at Serine-500 is important in modulating the dynamics of translation by controlling ribosome association. This is a fundamental mechanism governing the size and number of FMRP puncta that contain actively translating ribosomes. Finally through the use of pathogenic mutations, we emphasize the hierarchical contribution of FMRP's domains in translation regulation.
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Affiliation(s)
- Michelle Ninochka D'Souza
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, India, 560064.,Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012
| | - Sarayu Ramakrishna
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, India, 560064.,Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012
| | | | - Vishwaja Jhaveri
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Sreenath Ravindran
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Lahari Yeramala
- National Centre For Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India, 560065
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India, 560012
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Ravi S Muddashetty
- Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012.
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32
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Balcerak A, Macech-Klicka E, Wakula M, Tomecki R, Goryca K, Rydzanicz M, Chmielarczyk M, Szostakowska-Rodzos M, Wisniewska M, Lyczek F, Helwak A, Tollervey D, Kudla G, Grzybowska EA. The RNA-Binding Landscape of HAX1 Protein Indicates Its Involvement in Translation and Ribosome Assembly. Cells 2022; 11:cells11192943. [PMID: 36230905 PMCID: PMC9564044 DOI: 10.3390/cells11192943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 11/18/2022] Open
Abstract
HAX1 is a human protein with no known homologues or structural domains. Mutations in the HAX1 gene cause severe congenital neutropenia through mechanisms that are poorly understood. Previous studies reported the RNA-binding capacity of HAX1, but the role of this binding in physiology and pathology remains unexplained. Here, we report the transcriptome-wide characterization of HAX1 RNA targets using RIP-seq and CRAC, indicating that HAX1 binds transcripts involved in translation, ribosome biogenesis, and rRNA processing. Using CRISPR knockouts, we find that HAX1 RNA targets partially overlap with transcripts downregulated in HAX1 KO, implying a role in mRNA stabilization. Gene ontology analysis demonstrated that genes differentially expressed in HAX1 KO (including genes involved in ribosome biogenesis and translation) are also enriched in a subset of genes whose expression correlates with HAX1 expression in four analyzed neoplasms. The functional connection to ribosome biogenesis was also demonstrated by gradient sedimentation ribosome profiles, which revealed differences in the small subunit:monosome ratio in HAX1 WT/KO. We speculate that changes in HAX1 expression may be important for the etiology of HAX1-linked diseases through dysregulation of translation.
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Affiliation(s)
- Anna Balcerak
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Ewelina Macech-Klicka
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Maciej Wakula
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Rafal Tomecki
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Faculty of Biology, Institute of Genetics and Biotechnology, University of Warsaw, 02-106 Warsaw, Poland
| | - Krzysztof Goryca
- Genomics Core Facility, Centre of New Technologies University of Warsaw, 02-097 Warsaw, Poland
| | - Malgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland
| | - Mateusz Chmielarczyk
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Malgorzata Szostakowska-Rodzos
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Marta Wisniewska
- Laboratory of Biological Chemistry of Metal Ions, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Filip Lyczek
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
| | - Aleksandra Helwak
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Ewa A. Grzybowska
- Molecular and Translational Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, 02-781 Warsaw, Poland
- Correspondence:
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33
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Li H, Gavis ER. Drosophila FMRP controls miR-276-mediated regulation of nejire mRNA for space-filling dendrite development. G3 GENES|GENOMES|GENETICS 2022; 12:6697885. [PMID: 36102801 PMCID: PMC9635640 DOI: 10.1093/g3journal/jkac239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/30/2022] [Indexed: 11/30/2022]
Abstract
MicroRNAs are enriched in neurons and play important roles in dendritic spine development and synaptic plasticity. MicroRNA activity is controlled by a wide range of RNA-binding proteins. FMRP, a highly conserved RNA-binding protein, has been linked to microRNA-mediated gene regulation in axonal development and dendritic spine formation. FMRP also participates in dendritic arbor morphogenesis, but whether and how microRNAs contribute to its function in this process remains to be elucidated. Here, using Drosophila larval sensory neurons, we show that a FMRP-associated microRNA, miR-276, functions in FMRP-mediated space-filling dendrite morphogenesis. Using EGFP microRNA sensors, we demonstrate that FMRP likely acts by regulating miR-276a RNA targeting rather than by modulating microRNA levels. Supporting this conclusion, miR-276a coimmunoprecipitated with FMRP and this association was dependent on the FMRP KH domains. By testing putative targets of the FMRP–miR-276a regulatory axis, we identified nejire as a FMRP-associated mRNA and, using EGFP reporters, showed that the nejire 3′ untranslated region is a target of miR-276a in vivo. Genetic analysis places nejire downstream of the FMRP–miR-276a pathway in regulating dendrite patterning. Together, our findings support a model in which FMRP facilitates miR-276a-mediated control of nejire for proper dendrite space-filling morphology and shed light on microRNA-dependent dendrite developmental pathology of fragile X syndrome.
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Affiliation(s)
- Hui Li
- Department of Molecular Biology, Princeton University , Princeton, NJ 08544, USA
| | - Elizabeth R Gavis
- Department of Molecular Biology, Princeton University , Princeton, NJ 08544, USA
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34
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Susco SG, Ghosh S, Mazzucato P, Angelini G, Beccard A, Barrera V, Berryer MH, Messana A, Lam D, Hazelbaker DZ, Barrett LE. Molecular convergence between Down syndrome and fragile X syndrome identified using human pluripotent stem cell models. Cell Rep 2022; 40:111312. [PMID: 36070702 PMCID: PMC9465809 DOI: 10.1016/j.celrep.2022.111312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 04/19/2022] [Accepted: 08/12/2022] [Indexed: 11/27/2022] Open
Abstract
Down syndrome (DS), driven by an extra copy of chromosome 21 (HSA21), and fragile X syndrome (FXS), driven by loss of the RNA-binding protein FMRP, are two common genetic causes of intellectual disability and autism. Based upon the number of DS-implicated transcripts bound by FMRP, we hypothesize that DS and FXS may share underlying mechanisms. Comparing DS and FXS human pluripotent stem cell (hPSC) and glutamatergic neuron models, we identify increased protein expression of select targets and overlapping transcriptional perturbations. Moreover, acute upregulation of endogenous FMRP in DS patient cells using CRISPRa is sufficient to significantly reduce expression levels of candidate proteins and reverse 40% of global transcriptional perturbations. These results pinpoint specific molecular perturbations shared between DS and FXS that can be leveraged as a strategy for target prioritization; they also provide evidence for the functional relevance of previous associations between FMRP targets and disease-implicated genes.
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Affiliation(s)
- Sara G Susco
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Sulagna Ghosh
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Patrizia Mazzucato
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Gabriella Angelini
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Amanda Beccard
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Victor Barrera
- Bioinformatics Core, Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Martin H Berryer
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Angelica Messana
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Daisy Lam
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Dane Z Hazelbaker
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Lindy E Barrett
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA.
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35
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Internal Ribosome Entry Site (IRES)-Mediated Translation and Its Potential for Novel mRNA-Based Therapy Development. Biomedicines 2022; 10:biomedicines10081865. [PMID: 36009412 PMCID: PMC9405587 DOI: 10.3390/biomedicines10081865] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/26/2022] [Accepted: 07/29/2022] [Indexed: 11/17/2022] Open
Abstract
Many conditions can benefit from RNA-based therapies, namely, those targeting internal ribosome entry sites (IRESs) and their regulatory proteins, the IRES trans-acting factors (ITAFs). IRES-mediated translation is an alternative mechanism of translation initiation, known for maintaining protein synthesis when canonical translation is impaired. During a stress response, it contributes to cell reprogramming and adaptation to the new environment. The relationship between IRESs and ITAFs with tumorigenesis and resistance to therapy has been studied in recent years, proposing new therapeutic targets and treatments. In addition, IRES-dependent translation initiation dysregulation is also related to neurological and cardiovascular diseases, muscular atrophies, or other syndromes. The participation of these structures in the development of such pathologies has been studied, yet to a far lesser extent than in cancer. Strategies involving the disruption of IRES–ITAF interactions or the modification of ITAF expression levels may be used with great impact in the development of new therapeutics. In this review, we aim to comprehend the current data on groups of human pathologies associated with IRES and/or ITAF dysregulation and their application in the designing of new therapeutic approaches using them as targets or tools. Thus, we wish to summarise the evidence in the field hoping to open new promising lines of investigation toward personalised treatments.
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36
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Peng Y, Gavis ER. The Drosophila hnRNP F/H homolog Glorund recruits dFMRP to inhibit nanos translation elongation. Nucleic Acids Res 2022; 50:7067-7083. [PMID: 35699205 PMCID: PMC9262583 DOI: 10.1093/nar/gkac500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 12/24/2022] Open
Abstract
Translational control of maternal mRNAs generates spatial and temporal patterns of protein expression necessary to begin animal development. Translational repression of unlocalized nanos (nos) mRNA in late-stage Drosophila oocytes by the hnRNP F/H homolog, Glorund (Glo), is important for embryonic body patterning. While previous work has suggested that repression occurs at both the translation initiation and elongation phases, the molecular mechanism by which Glo regulates nos translation remains elusive. Here, we have identified the Drosophila fragile X mental retardation protein, dFMRP, as a Glo interaction partner with links to the translational machinery. Using an oocyte-based in vitro translation system, we confirmed that Glo regulates both initiation and elongation of a nos translational reporter and showed that dFMRP specifically represses translation elongation and promotes ribosome stalling. Furthermore, we combined mutational analysis and in vivo and in vitro binding assays to show that Glo's qRRM2 domain specifically and directly interacts with dFMRP. Our findings suggest that Glo regulates nos translation elongation by recruiting dFMRP and that Glo's RNA-binding domains can also function as protein-protein interaction interfaces critical for its regulatory functions. Additionally, they reveal a mechanism for targeting dFMRP to specific transcripts.
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Affiliation(s)
- Yingshi Peng
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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37
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Seo SS, Louros SR, Anstey N, Gonzalez-Lozano MA, Harper CB, Verity NC, Dando O, Thomson SR, Darnell JC, Kind PC, Li KW, Osterweil EK. Excess ribosomal protein production unbalances translation in a model of Fragile X Syndrome. Nat Commun 2022; 13:3236. [PMID: 35688821 PMCID: PMC9187743 DOI: 10.1038/s41467-022-30979-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 05/23/2022] [Indexed: 12/21/2022] Open
Abstract
Dysregulated protein synthesis is a core pathogenic mechanism in Fragile X Syndrome (FX). The mGluR Theory of FX predicts that pathological synaptic changes arise from the excessive translation of mRNAs downstream of mGlu1/5 activation. Here, we use a combination of CA1 pyramidal neuron-specific TRAP-seq and proteomics to identify the overtranslating mRNAs supporting exaggerated mGlu1/5 -induced long-term synaptic depression (mGluR-LTD) in the FX mouse model (Fmr1−/y). Our results identify a significant increase in the translation of ribosomal proteins (RPs) upon mGlu1/5 stimulation that coincides with a reduced translation of long mRNAs encoding synaptic proteins. These changes are mimicked and occluded in Fmr1−/y neurons. Inhibiting RP translation significantly impairs mGluR-LTD and prevents the length-dependent shift in the translating population. Together, these results suggest that pathological changes in FX result from a length-dependent alteration in the translating population that is supported by excessive RP translation. Dysregulated protein synthesis is key contributor to Fragile X syndrome. Here the authors identify a relationship between ribosome expression and the translation of long mRNAs that contributes to synaptic weakening in a model of Fragile X syndrome.
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Affiliation(s)
- Sang S Seo
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Susana R Louros
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Natasha Anstey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Callista B Harper
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Nicholas C Verity
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Owen Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Sophie R Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Jennifer C Darnell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Emily K Osterweil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK. .,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK.
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38
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Donnard E, Shu H, Garber M. Single cell transcriptomics reveals dysregulated cellular and molecular networks in a fragile X syndrome model. PLoS Genet 2022; 18:e1010221. [PMID: 35675353 PMCID: PMC9212148 DOI: 10.1371/journal.pgen.1010221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 06/21/2022] [Accepted: 04/27/2022] [Indexed: 02/07/2023] Open
Abstract
Despite advances in understanding the pathophysiology of Fragile X syndrome (FXS), its molecular basis is still poorly understood. Whole brain tissue expression profiles have proved surprisingly uninformative, therefore we applied single cell RNA sequencing to profile an FMRP deficient mouse model with higher resolution. We found that the absence of FMRP results in highly cell type specific gene expression changes that are strongest among specific neuronal types, where FMRP-bound mRNAs were prominently downregulated. Metabolic pathways including translation and respiration are significantly upregulated across most cell types with the notable exception of excitatory neurons. These effects point to a potential difference in the activity of mTOR pathways, and together with other dysregulated pathways, suggest an excitatory-inhibitory imbalance in the Fmr1-knock out cortex that is exacerbated by astrocytes. Our data demonstrate that FMRP loss affects abundance of key cellular communication genes that potentially affect neuronal synapses and provide a resource for interrogating the biological basis of this disorder. Fragile X syndrome is a leading genetic cause of inherited intellectual disability and autism spectrum disorder. It results from the inactivation of a single gene, FMR1 and hence the loss of its encoded protein FMRP. Despite decades of intensive research, we still lack an overview of the molecular and biological consequences of the disease. Using single cell RNA sequencing, we profiled cells from the brain of healthy mice and of knock-out mice lacking the FMRP protein, a common model for this disease, to identify molecular changes that happen across different cell types. We find neurons are the most impacted cell type, where genes in multiple pathways are similarly impacted. This includes transcripts known to be bound by FMRP, which are collectively decreased only in neurons but not in other cell types. Our results show how the loss of FMRP affects the intricate interactions between different brain cell types, which could provide new perspectives to the development of therapeutic interventions.
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Affiliation(s)
- Elisa Donnard
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (ED); (HS); (MG)
| | - Huan Shu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (ED); (HS); (MG)
| | - Manuel Garber
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Dermatology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (ED); (HS); (MG)
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39
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Lee A, Xu J, Wen Z, Jin P. Across Dimensions: Developing 2D and 3D Human iPSC-Based Models of Fragile X Syndrome. Cells 2022; 11:1725. [PMID: 35681419 PMCID: PMC9179297 DOI: 10.3390/cells11111725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 02/01/2023] Open
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism spectrum disorder. FXS is caused by a cytosine-guanine-guanine (CGG) trinucleotide repeat expansion in the untranslated region of the FMR1 gene leading to the functional loss of the gene's protein product FMRP. Various animal models of FXS have provided substantial knowledge about the disorder. However, critical limitations exist in replicating the pathophysiological mechanisms. Human induced pluripotent stem cells (hiPSCs) provide a unique means of studying the features and processes of both normal and abnormal human neurodevelopment in large sample quantities in a controlled setting. Human iPSC-based models of FXS have offered a better understanding of FXS pathophysiology specific to humans. This review summarizes studies that have used hiPSC-based two-dimensional cellular models of FXS to reproduce the pathology, examine altered gene expression and translation, determine the functions and targets of FMRP, characterize the neurodevelopmental phenotypes and electrophysiological features, and, finally, to reactivate FMR1. We also provide an overview of the most recent studies using three-dimensional human brain organoids of FXS and end with a discussion of current limitations and future directions for FXS research using hiPSCs.
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Affiliation(s)
- Azalea Lee
- Neuroscience Graduate Program, Emory University, Atlanta, GA 30322, USA;
- MD/PhD Program, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jie Xu
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA 30322, USA;
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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40
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Li H, Gavis ER. The Drosophila fragile X mental retardation protein modulates the neuronal cytoskeleton to limit dendritic arborization. Development 2022; 149:275257. [DOI: 10.1242/dev.200379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/21/2022] [Indexed: 01/02/2023]
Abstract
ABSTRACT
Dendritic arbor development is a complex, highly regulated process. Post-transcriptional regulation mediated by RNA-binding proteins plays an important role in neuronal dendrite morphogenesis by delivering on-site, on-demand protein synthesis. Here, we show how the Drosophila fragile X mental retardation protein (FMRP), a conserved RNA-binding protein, limits dendrite branching to ensure proper neuronal function during larval sensory neuron development. FMRP knockdown causes increased dendritic terminal branch growth and a resulting overelaboration defect due, in part, to altered microtubule stability and dynamics. FMRP also controls dendrite outgrowth by regulating the Drosophila profilin homolog chickadee (chic). FMRP colocalizes with chic mRNA in dendritic granules and regulates its dendritic localization and protein expression. Whereas RNA-binding domains KH1 and KH2 are both crucial for FMRP-mediated dendritic regulation, KH2 specifically is required for FMRP granule formation and chic mRNA association, suggesting a link between dendritic FMRP granules and FMRP function in dendrite elaboration. Our studies implicate FMRP-mediated modulation of both the neuronal microtubule and actin cytoskeletons in multidendritic neuronal architecture, and provide molecular insight into FMRP granule formation and its relevance to FMRP function in dendritic patterning.
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Affiliation(s)
- Hui Li
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Elizabeth R. Gavis
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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41
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Francisco-Velilla R, Embarc-Buh A, Del Caño-Ochoa F, Abellan S, Vilar M, Alvarez S, Fernandez-Jaen A, Kour S, Rajan DS, Pandey UB, Ramón-Maiques S, Martinez-Salas E. Functional and structural deficiencies of Gemin5 variants associated with neurological disorders. Life Sci Alliance 2022; 5:5/7/e202201403. [PMID: 35393353 PMCID: PMC8989681 DOI: 10.26508/lsa.202201403] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 12/15/2022] Open
Abstract
Dysfunction of RNA-binding proteins is often linked to a wide range of human disease, particularly with neurological conditions. Gemin5 is a member of the survival of the motor neurons (SMN) complex, a ribosome-binding protein and a translation reprogramming factor. Recently, pathogenic mutations in Gemin5 have been reported, but the functional consequences of these variants remain elusive. Here, we report functional and structural deficiencies associated with compound heterozygosity variants within the Gemin5 gene found in patients with neurodevelopmental disorders. These clinical variants are located in key domains of Gemin5, the tetratricopeptide repeat (TPR)-like dimerization module and the noncanonical RNA-binding site 1 (RBS1). We show that the TPR-like variants disrupt protein dimerization, whereas the RBS1 variant confers protein instability. All mutants are defective in the interaction with protein networks involved in translation and RNA-driven pathways. Importantly, the TPR-like variants fail to associate with native ribosomes, hampering its involvement in translation control and establishing a functional difference with the wild-type protein. Our study provides insights into the molecular basis of disease associated with malfunction of the Gemin5 protein.
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Affiliation(s)
- Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Francisco Del Caño-Ochoa
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Marçal Vilar
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Sara Alvarez
- New Integrated Medical Genetics (NIMGENETICS), Madrid, Spain
| | - Alberto Fernandez-Jaen
- Neuropediatric Department, Hospital Universitario Quirónsalud, Madrid, Spain.,School of Medicine, Universidad Europea de Madrid, Madrid, Spain
| | - Sukhleen Kour
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Deepa S Rajan
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Santiago Ramón-Maiques
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Cientificas - Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
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42
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CMTr cap-adjacent 2'-O-ribose mRNA methyltransferases are required for reward learning and mRNA localization to synapses. Nat Commun 2022; 13:1209. [PMID: 35260552 PMCID: PMC8904806 DOI: 10.1038/s41467-022-28549-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 01/18/2022] [Indexed: 11/25/2022] Open
Abstract
Cap-adjacent nucleotides of animal, protist and viral mRNAs can be O-methylated at the 2‘ position of the ribose (cOMe). The functions of cOMe in animals, however, remain largely unknown. Here we show that the two cap methyltransferases (CMTr1 and CMTr2) of Drosophila can methylate the ribose of the first nucleotide in mRNA. Double-mutant flies lack cOMe but are viable. Consistent with prominent neuronal expression, they have a reward learning defect that can be rescued by conditional expression in mushroom body neurons before training. Among CMTr targets are cell adhesion and signaling molecules. Many are relevant for learning, and are also targets of Fragile X Mental Retardation Protein (FMRP). Like FMRP, cOMe is required for localization of untranslated mRNAs to synapses and enhances binding of the cap binding complex in the nucleus. Hence, our study reveals a mechanism to co-transcriptionally prime mRNAs by cOMe for localized protein synthesis at synapses. The two cap methyltransferases (CMTrs) redundantly methylate riboses of first cap adjacent nucleotides in messenger RNAs in Drosophila. Here, CMTrs are required for reward learning and localization of untranslated messenger RNAs to synapses.
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43
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Yildirim Z, Baboo S, Hamid SM, Dogan AE, Tufanli O, Robichaud S, Emerton C, Diedrich JK, Vatandaslar H, Nikolos F, Gu Y, Iwawaki T, Tarling E, Ouimet M, Nelson DL, Yates JR, Walter P, Erbay E. Intercepting IRE1 kinase-FMRP signaling prevents atherosclerosis progression. EMBO Mol Med 2022; 14:e15344. [PMID: 35191199 PMCID: PMC8988208 DOI: 10.15252/emmm.202115344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 12/15/2022] Open
Abstract
Fragile X Mental Retardation protein (FMRP), widely known for its role in hereditary intellectual disability, is an RNA‐binding protein (RBP) that controls translation of select mRNAs. We discovered that endoplasmic reticulum (ER) stress induces phosphorylation of FMRP on a site that is known to enhance translation inhibition of FMRP‐bound mRNAs. We show ER stress‐induced activation of Inositol requiring enzyme‐1 (IRE1), an ER‐resident stress‐sensing kinase/endoribonuclease, leads to FMRP phosphorylation and to suppression of macrophage cholesterol efflux and apoptotic cell clearance (efferocytosis). Conversely, FMRP deficiency and pharmacological inhibition of IRE1 kinase activity enhances cholesterol efflux and efferocytosis, reducing atherosclerosis in mice. Our results provide mechanistic insights into how ER stress‐induced IRE1 kinase activity contributes to macrophage cholesterol homeostasis and suggests IRE1 inhibition as a promising new way to counteract atherosclerosis.
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Affiliation(s)
- Zehra Yildirim
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Molecular Biology and Genetics, National Nanotechnology Center, Bilkent University, Ankara, Turkey
| | - Sabyasachi Baboo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Syed M Hamid
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Asli E Dogan
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Department of Molecular Biology and Genetics, National Nanotechnology Center, Bilkent University, Ankara, Turkey
| | - Ozlem Tufanli
- Lagone Medical Center, New York University, New York, NY, USA
| | - Sabrina Robichaud
- Department of Biochemistry, Microbiology and Immunology, Heart Institute, University of Ottawa, Ottawa, ON, Canada
| | - Christina Emerton
- Department of Biochemistry, Microbiology and Immunology, Heart Institute, University of Ottawa, Ottawa, ON, Canada
| | - Jolene K Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Hasan Vatandaslar
- Institute of Molecular Health Sciences, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Fotis Nikolos
- Samuel Oschin Cancer Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Yanghong Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Takao Iwawaki
- Department of Life Science, Medical Research Institute, Kanazawa Medical University, Ishikawa, Japan
| | - Elizabeth Tarling
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Mireille Ouimet
- Department of Biochemistry, Microbiology and Immunology, Heart Institute, University of Ottawa, Ottawa, ON, Canada
| | - David L Nelson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - John R Yates
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Peter Walter
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA, USA
| | - Ebru Erbay
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
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44
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Starke EL, Zius K, Barbee SA. FXS causing missense mutations disrupt FMRP granule formation, dynamics, and function. PLoS Genet 2022; 18:e1010084. [PMID: 35202393 PMCID: PMC8903291 DOI: 10.1371/journal.pgen.1010084] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 03/08/2022] [Accepted: 02/08/2022] [Indexed: 01/01/2023] Open
Abstract
Fragile X Syndrome (FXS) is the most prevalent cause of inherited mental deficiency and is the most common monogenetic cause of autism spectral disorder (ASD). Here, we demonstrate that disease-causing missense mutations in the conserved K homology (KH) RNA binding domains (RBDs) of FMRP cause defects in its ability to form RNA transport granules in neurons. Using molecular, genetic, and imaging approaches in the Drosophila FXS model system, we show that the KH1 and KH2 domains of FMRP regulate distinct aspects of neuronal FMRP granule formation, dynamics, and transport. Furthermore, mutations in the KH domains disrupt translational repression in cells and the localization of known FMRP target mRNAs in neurons. These results suggest that the KH domains play an essential role in neuronal FMRP granule formation and function which may be linked to the molecular pathogenesis of FXS. Fragile X Syndrome (FXS) is the most common inherited neurodevelopmental disorder in humans and single gene cause of autism. Most cases of FXS are caused by the complete loss of a single protein (called FMRP). This has made it particularly difficult to understand which of the normal functions of FMRP are disrupted in cases of FXS. Recently, advances in high-throughput sequencing technologies have led to the discovery of patients with severe FXS caused by single mutations in important regions of the FMRP protein. Using a well-characterized FXS model system, we have found that two disease-causing mutations in FMRP disrupt the formation, dynamics, and function of RNA- and protein-containing granules in neurons. These granules have been shown to be involved in the transport of mRNA cargos in axons and dendrites. Disruption of these granules is linked to defects in synaptic development and plasticity. Our results show that two regions of the FMRP protein play a critical role in the control of FMRP granules. These findings suggest the disruption of these processes may be linked to FXS pathogenesis.
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Affiliation(s)
- Emily L. Starke
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
| | - Keelan Zius
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
| | - Scott A. Barbee
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
- Molecular and Cellular Biophysics Program, University of Denver, Denver, Colorado, United States of America
- * E-mail:
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45
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Fakhraldeen SA, Berry SM, Beebe DJ, Roopra A, Bisbach CM, Spiegelman VS, Niemi NM, Alexander CM. Enhanced immunoprecipitation techniques for the identification of RNA-binding protein partners: IGF2BP1 interactions in mammary epithelial cells. J Biol Chem 2022; 298:101649. [PMID: 35104504 PMCID: PMC8891971 DOI: 10.1016/j.jbc.2022.101649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 11/24/2022] Open
Abstract
RNA-binding proteins (RBPs) regulate the expression of large cohorts of RNA species to produce programmatic changes in cellular phenotypes. To describe the function of RBPs within a cell, it is key to identify their mRNA-binding partners. This is often done by crosslinking nucleic acids to RBPs, followed by chemical release of the nucleic acid fragments for analysis. However, this methodology is lengthy, which involves complex processing with attendant sample losses, thus large amounts of starting materials and prone to artifacts. To evaluate potential alternative technologies, we tested “exclusion-based” purification of immunoprecipitates (IFAST or SLIDE) and report here that these methods can efficiently, rapidly, and specifically isolate RBP–RNA complexes. The analysis requires less than 1% of the starting material required for techniques that include crosslinking. Depending on the antibody used, 50% to 100% starting protein can be retrieved, facilitating the assay of endogenous levels of RBPs; the isolated ribonucleoproteins are subsequently analyzed using standard techniques, to provide a comprehensive portrait of RBP complexes. Using exclusion-based techniques, we show that the mRNA-binding partners for RBP IGF2BP1 in cultured mammary epithelial cells are enriched in mRNAs important for detoxifying superoxides (specifically glutathione peroxidase [GPX]-1 and GPX-2) and mRNAs encoding mitochondrial proteins. We show that these interactions are functionally significant, as loss of function of IGF2BP1 leads to destabilization of GPX mRNAs and reduces mitochondrial membrane potential and oxygen consumption. We speculate that this underlies a consistent requirement for IGF2BP1 for the expression of clonogenic activity in vitro.
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Affiliation(s)
- Saja A Fakhraldeen
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Scott M Berry
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - David J Beebe
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Avtar Roopra
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Celia M Bisbach
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Vladimir S Spiegelman
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Natalie M Niemi
- Department of Biochemistry & Molecular Biophysics, Washington University in St Louis
| | - Caroline M Alexander
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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Joo M, Yeom JH, Choi Y, Jun H, Song W, Kim HL, Lee K, Shin E. Specialised ribosomes as versatile regulators of gene expression. RNA Biol 2022; 19:1103-1114. [PMID: 36255182 PMCID: PMC9586635 DOI: 10.1080/15476286.2022.2135299] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The ribosome has long been thought to be a homogeneous cellular machine that constitutively and globally synthesises proteins from mRNA. However, recent studies have revealed that ribosomes are highly heterogeneous, dynamic macromolecular complexes with specialised roles in translational regulation in many organisms across the kingdoms. In this review, we summarise the current understanding of ribosome heterogeneity and the specialised functions of heterogeneous ribosomes. We also discuss specialised translation systems that utilise orthogonal ribosomes.
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Affiliation(s)
- Minju Joo
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Ji-Hyun Yeom
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Younkyung Choi
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Hyeon Jun
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Wooseok Song
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Hyun-Lee Kim
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Kangseok Lee
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Eunkyoung Shin
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
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47
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Forman-Kay JD, Ditlev JA, Nosella ML, Lee HO. What are the distinguishing features and size requirements of biomolecular condensates and their implications for RNA-containing condensates? RNA (NEW YORK, N.Y.) 2022; 28:36-47. [PMID: 34772786 PMCID: PMC8675286 DOI: 10.1261/rna.079026.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Exciting recent work has highlighted that numerous cellular compartments lack encapsulating lipid bilayers (often called "membraneless organelles"), and that their structure and function are central to the regulation of key biological processes, including transcription, RNA splicing, translation, and more. These structures have been described as "biomolecular condensates" to underscore that biomolecules can be significantly concentrated in them. Many condensates, including RNA granules and processing bodies, are enriched in proteins and nucleic acids. Biomolecular condensates exhibit a range of material states from liquid- to gel-like, with the physical process of liquid-liquid phase separation implicated in driving or contributing to their formation. To date, in vitro studies of phase separation have provided mechanistic insights into the formation and function of condensates. However, the link between the often micron-sized in vitro condensates with nanometer-sized cellular correlates has not been well established. Consequently, questions have arisen as to whether cellular structures below the optical resolution limit can be considered biomolecular condensates. Similarly, the distinction between condensates and discrete dynamic hub complexes is debated. Here we discuss the key features that define biomolecular condensates to help understand behaviors of structures containing and generating RNA.
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Affiliation(s)
- Julie D Forman-Kay
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jonathon A Ditlev
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Michael L Nosella
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Hyun O Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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48
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RNA-binding protein dysfunction in neurodegeneration. Essays Biochem 2021; 65:975-986. [PMID: 34927200 DOI: 10.1042/ebc20210024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022]
Abstract
Protein homeostasis (proteostasis) is a prerequisite for cellular viability and plasticity. In particular, post-mitotic cells such as neurons rely on a tightly regulated safeguard system that allows for regulated protein expression. Previous investigations have identified RNA-binding proteins (RBPs) as crucial regulators of protein expression in nerve cells. However, during neurodegeneration, their ability to control the proteome is progressively disrupted. In this review, we examine the malfunction of key RBPs such as TAR DNA-binding protein 43 (TDP-43), Fused in Sarcoma (FUS), Staufen, Pumilio and fragile-X mental retardation protein (FMRP). Therefore, we focus on two key aspects of RBP dysfunctions in neurodegeneration: protein aggregation and dysregulation of their target RNAs. Moreover, we discuss how the chaperone system responds to changes in the RBP-controlled transcriptome. Based on recent findings, we propose a two-hit model in which both, harmful RBP deposits and target mRNA mistranslation contribute to neurodegeneration observed in RBPathologies.
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49
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Khlebodarova TM. The molecular view of mechanical stress of brain cells, local translation, and neurodegenerative diseases. Vavilovskii Zhurnal Genet Selektsii 2021; 25:92-100. [PMID: 34901706 PMCID: PMC8629365 DOI: 10.18699/vj21.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/03/2022] Open
Abstract
The assumption that chronic mechanical stress in brain cells stemming from intracranial hypertension,
arterial hypertension, or mechanical injury is a risk factor for neurodegenerative diseases was put forward in the
1990s and has since been supported. However, the molecular mechanisms that underlie the way from cell exposure to mechanical stress to disturbances in synaptic plasticity followed by changes in behavior, cognition, and
memory are still poorly understood. Here we review (1) the current knowledge of molecular mechanisms regulating local translation and the actin cytoskeleton state at an activated synapse, where they play a key role in the
formation of various sorts of synaptic plasticity and long-term memory, and (2) possible pathways of mechanical
stress intervention. The roles of the mTOR (mammalian target of rapamycin) signaling pathway; the RNA-binding
FMRP protein; the CYFIP1 protein, interacting with FMRP; the family of small GTPases; and the WAVE regulatory
complex in the regulation of translation initiation and actin cytoskeleton rearrangements in dendritic spines of the
activated synapse are discussed. Evidence is provided that chronic mechanical stress may result in aberrant activation of mTOR signaling and the WAVE regulatory complex via the YAP/TAZ system, the key sensor of mechanical
signals, and influence the associated pathways regulating the formation of F actin filaments and the dendritic spine
structure. These consequences may be a risk factor for various neurological conditions, including autistic spectrum
disorders and epileptic encephalopathy. In further consideration of the role of the local translation system in the
development of neuropsychic and neurodegenerative diseases, an original hypothesis was put forward that one
of the possible causes of synaptopathies is impaired proteome stability associated with mTOR hyperactivity and
formation of complex dynamic modes of de novo protein synthesis in response to synapse-stimulating factors,
including chronic mechanical stress.
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Affiliation(s)
- T M Khlebodarova
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia Kurchatov Genomic Center of the Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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50
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Aleshkina D, Iyyappan R, Lin CJ, Masek T, Pospisek M, Susor A. ncRNA BC1 influences translation in the oocyte. RNA Biol 2021; 18:1893-1904. [PMID: 33491548 PMCID: PMC8583082 DOI: 10.1080/15476286.2021.1880181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/17/2020] [Accepted: 01/15/2021] [Indexed: 01/06/2023] Open
Abstract
Regulation of translation is essential for the diverse biological processes involved in development. Particularly, mammalian oocyte development requires the precisely controlled translation of maternal transcripts to coordinate meiotic and early embryo progression while transcription is silent. It has been recently reported that key components of mRNA translation control are short and long noncoding RNAs (ncRNAs). We found that the ncRNABrain cytoplasmic 1 (BC1) has a role in the fully grown germinal vesicle (GV) mouse oocyte, where is highly expressed in the cytoplasm associated with polysomes. Overexpression of BC1 in GV oocyte leads to a minute decrease in global translation with a significant reduction of specific mRNA translation via interaction with the Fragile X Mental Retardation Protein (FMRP). BC1 performs a repressive role in translation only in the GV stage oocyte without forming FMRP or Poly(A) granules. In conclusion, BC1 acts as the translational repressor of specific mRNAs in the GV stage via its binding to a subset of mRNAs and physical interaction with FMRP. The results reported herein contribute to the understanding of the molecular mechanisms of developmental events connected with maternal mRNA translation.
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Affiliation(s)
- D. Aleshkina
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
| | - R. Iyyappan
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
| | - Ch. J. Lin
- MRC Centre for Reproductive Health, The University of Edinburgh, Edinburgh, UK
| | - T. Masek
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - M. Pospisek
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - A. Susor
- Laboratory of Biochemistry and Molecular Biology of Germ Cells, Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
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