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Cesari E, Farini D, Medici V, Ehrmann I, Guerra M, Testa E, Naro C, Geloso MC, Pagliarini V, La Barbera L, D’Amelio M, Orsini T, Vecchioli SF, Tamagnone L, Fort P, Viscomi MT, Elliott DJ, Sette C. Differential expression of paralog RNA binding proteins establishes a dynamic splicing program required for normal cerebral cortex development. Nucleic Acids Res 2024; 52:4167-4184. [PMID: 38324473 PMCID: PMC11077083 DOI: 10.1093/nar/gkae071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024] Open
Abstract
Sam68 and SLM2 are paralog RNA binding proteins (RBPs) expressed in the cerebral cortex and display similar splicing activities. However, their relative functions during cortical development are unknown. We found that these RBPs exhibit an opposite expression pattern during development. Sam68 expression declines postnatally while SLM2 increases after birth, and this developmental pattern is reinforced by hierarchical control of Sam68 expression by SLM2. Analysis of Sam68:Slm2 double knockout (Sam68:Slm2dko) mice revealed hundreds of exons that respond to joint depletion of these proteins. Moreover, parallel analysis of single and double knockout cortices indicated that exons regulated mainly by SLM2 are characterized by a dynamic splicing pattern during development, whereas Sam68-dependent exons are spliced at relatively constant rates. Dynamic splicing of SLM2-sensitive exons is completely suppressed in the Sam68:Slm2dko developing cortex. Sam68:Slm2dko mice die perinatally with defects in neurogenesis and in neuronal differentiation, and develop a hydrocephalus, consistent with splicing alterations in genes related to these biological processes. Thus, our study reveals that developmental control of separate Sam68 and Slm2 paralog genes encoding homologous RBPs enables the orchestration of a dynamic splicing program needed for brain development and viability, while ensuring a robust redundant mechanism that supports proper cortical development.
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Affiliation(s)
- Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Donatella Farini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Vanessa Medici
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Ingrid Ehrmann
- Newcastle University Centre for Cancer, Newcastle University Institute of Biosciences, Newcastle NE1 3BZ, UK
| | - Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Erika Testa
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Maria Concetta Geloso
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
| | - Livia La Barbera
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Marcello D’Amelio
- Fondazione Santa Lucia IRCCS, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
- Università Campus Bio-Medico di Roma, Via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Tiziana Orsini
- Institute of Biochemistry and Cell Biology, National Research Council (IBBC/CNR), Monterotondo, 00015 Rome, Italy
| | - Stefano Farioli Vecchioli
- Institute of Biochemistry and Cell Biology, National Research Council (IBBC/CNR), Monterotondo, 00015 Rome, Italy
| | - Luca Tamagnone
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - Philippe Fort
- Centre de Recherche en Biologie Cellulaire de Montpellier, University of Montpellier, CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 05, France
| | - Maria Teresa Viscomi
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
- Department of Life Science and Public Health, Section of Histology and Embryology, Catholic University of the Sacred Heart, Rome
| | - David J Elliott
- Newcastle University Centre for Cancer, Newcastle University Institute of Biosciences, Newcastle NE1 3BZ, UK
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy
- Fondazione Policlinico Agostino Gemelli IRCCS, Largo Agostino Gemelli, 00168 Rome, Italy
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Han KA, Yoon TH, Kim J, Lee J, Lee JY, Jang G, Um JW, Kim JK, Ko J. Specification of neural circuit architecture shaped by context-dependent patterned LAR-RPTP microexons. Nat Commun 2024; 15:1624. [PMID: 38388459 PMCID: PMC10883964 DOI: 10.1038/s41467-024-45695-0] [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: 07/13/2023] [Accepted: 01/30/2024] [Indexed: 02/24/2024] Open
Abstract
LAR-RPTPs are evolutionarily conserved presynaptic cell-adhesion molecules that orchestrate multifarious synaptic adhesion pathways. Extensive alternative splicing of LAR-RPTP mRNAs may produce innumerable LAR-RPTP isoforms that act as regulatory "codes" for determining the identity and strength of specific synapse signaling. However, no direct evidence for this hypothesis exists. Here, using targeted RNA sequencing, we detected LAR-RPTP mRNAs in diverse cell types across adult male mouse brain areas. We found pronounced cell-type-specific patterns of two microexons, meA and meB, in Ptprd mRNAs. Moreover, diverse neural circuits targeting the same neuronal populations were dictated by the expression of different Ptprd variants with distinct inclusion patterns of microexons. Furthermore, conditional ablation of Ptprd meA+ variants at presynaptic loci of distinct hippocampal circuits impaired distinct modes of synaptic transmission and objection-location memory. Activity-triggered alterations of the presynaptic Ptprd meA code in subicular neurons mediates NMDA receptor-mediated postsynaptic responses in CA1 neurons and objection-location memory. Our data provide the evidence of cell-type- and/or circuit-specific expression patterns in vivo and physiological functions of LAR-RPTP microexons that are dynamically regulated.
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Affiliation(s)
- Kyung Ah Han
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea
| | - Taek-Han Yoon
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
| | - Jinhu Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
| | - Jusung Lee
- Department of New Biology, DGIST, Daegu, 42988, Korea
| | - Ju Yeon Lee
- Korea Basic Science Institute, Research Center for Bioconvergence Analysis, Cheongju, 28119, Korea
| | - Gyubin Jang
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea
| | - Ji Won Um
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea
| | - Jong Kyoung Kim
- Department of New Biology, DGIST, Daegu, 42988, Korea
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea.
- Center for Synapse Diversity and Specificity, DGIST, Daegu, 42988, Korea.
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Dabrowski KR, Floris G, Gillespie A, Daws SE. Orbitofrontal intronic circular RNA from Nrxn3 mediates reward learning and motivation for reward. Prog Neurobiol 2024; 232:102546. [PMID: 38036039 PMCID: PMC10843848 DOI: 10.1016/j.pneurobio.2023.102546] [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: 07/17/2023] [Revised: 10/27/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
The orbitofrontal cortex (OFC) is a vital component of brain reward circuitry that is important for reward seeking behavior. However, OFC-mediated molecular mechanisms underlying rewarding behavior are understudied. Here, we report the first circular RNA (circRNA) profile associated with appetitive reward and identify regulation of 92 OFC circRNAs by sucrose self-administration. Among these changes, we observed downregulation of circNrxn3, a circRNA originating from neurexin 3 (Nrxn3), a gene involved in synaptogenesis, learning, and memory. Transcriptomic profiling via RNA sequencing and qPCR of the OFC following in vivo knock-down of circNrxn3 revealed differential regulation of genes associated with pathways important for learning and memory and altered splicing of Nrxn3. Furthermore, circNrxn3 knock-down enhanced sucrose self-administration and motivation for sucrose. Using RNA-immunoprecipitation, we report binding of circNrxn3 to the known Nrxn3 splicing factor SAM68. circNrxn3 is the first reported circRNA capable of regulating reward behavior and circNrxn3-mediated interactions with SAM68 may impact subsequent downstream processing of RNAs such as the regulation of gene expression and splicing.
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Affiliation(s)
- Konrad R Dabrowski
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Department of Biology, Temple University, Philadelphia, PA, USA
| | - Gabriele Floris
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Aria Gillespie
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Stephanie E Daws
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA; Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA.
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Li W, Li X, Gao Y, Xiong C, Tang Z. Emerging roles of RNA binding proteins in intervertebral disc degeneration and osteoarthritis. Orthop Surg 2023; 15:3015-3025. [PMID: 37803912 PMCID: PMC10694020 DOI: 10.1111/os.13851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/06/2023] [Accepted: 07/19/2023] [Indexed: 10/08/2023] Open
Abstract
The etiology of intervertebral disc degeneration (IDD) and osteoarthritis (OA) is complex and multifactorial. Both predisposing genes and environmental factors are involved in the pathogenesis of IDD and OA. Moreover, epigenetic modifications affect the development of IDD and OA. Dysregulated phenotypes of nucleus pulposus (NP) cells and OA chondrocytes, including apoptosis, extracellular matrix disruption, inflammation, and angiogenesis, are involved at all developmental stages of IDD and OA. RNA binding proteins (RBPs) have recently been recognized as essential post-transcriptional regulators of gene expression. RBPs are implicated in many cellular processes, such as proliferation, differentiation, and apoptosis. Recently, several RBPs have been reported to be associated with the pathogenesis of IDD and OA. This review briefly summarizes the current knowledge on the RNA-regulatory networks controlled by RBPs and their potential roles in the pathogenesis of IDD and OA. These initial findings support the idea that specific modulation of RBPs represents a promising approach for managing IDD and OA.
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Affiliation(s)
- Wen Li
- Department of EmergencyGeneral Hospital of Central Theater Command of PLAWuhanChina
| | - Xing‐Hua Li
- Department of EmergencyGeneral Hospital of Central Theater Command of PLAWuhanChina
| | - Yang Gao
- Department of OrthopaedicGeneral Hospital of Central Theater Command of PLAWuhanChina
| | - Cheng‐Jie Xiong
- Department of OrthopaedicGeneral Hospital of Central Theater Command of PLAWuhanChina
| | - Zhong‐Zhi Tang
- Department of EmergencyGeneral Hospital of Central Theater Command of PLAWuhanChina
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5
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Yang C, Gao Z, Wang Y, Zhang Q, Bai M, Yang H, Guo J, Zhang Y. Genome-wide DNA methylation analysis reveals layer-specific methylation patterns in deer antler tissue. Gene 2023; 884:147744. [PMID: 37640118 DOI: 10.1016/j.gene.2023.147744] [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: 05/21/2023] [Revised: 08/16/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
This paper explored using of deer antlers as a model for studying rapid growth and cartilage formation in mammals. The genes and regulatory mechanisms involved in antler chondrogenesis are poorly understood, however, previous research has suggested that DNA methylation played a key role in antler regeneration. By using fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP), this study measured DNA methylation levels in cartilage (CA) and reserve mesenchyme (RM) cells and tissues. Results showed that RM cells (RMCs) DNA methylation levels were significantly lower than those of CA, suggesting that DNA demethylation may be involved in antler fast cartilage differentiation. The study also identified 20 methylated fragments specific to RMCs or CA using the methylation-sensitive amplified polymorphism (MSAP) technique and confirmed these findings using southern blot analysis. The data provide the first experimental evidence of a link between epigenetic regulation and rapid cartilage differentiation in antlers.
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Affiliation(s)
- Chun Yang
- College of Basic Medicine, Beihua University, Jilin, PR China.
| | - Zizheng Gao
- College of Basic Medicine, Beihua University, Jilin, PR China
| | - Yukun Wang
- School of Stomatology, Beihua University, Jilin, PR China
| | - Qi Zhang
- School of Public Health, Beihua University, Jilin, PR China
| | - Muran Bai
- School of Stomatology, Beihua University, Jilin, PR China
| | - Huiran Yang
- School of Public Health, Beihua University, Jilin, PR China
| | - Junqi Guo
- The Third Clinical Medicine Affiliated to Changchun University of Chinese Medicine, Changchun, PR China.
| | - Yan Zhang
- School of Public Health, Beihua University, Jilin, PR China.
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6
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Ruan X, Hu K, Zhang X. PIE-seq: identifying RNA-binding protein targets by dual RNA-deaminase editing and sequencing. Nat Commun 2023; 14:3275. [PMID: 37280234 DOI: 10.1038/s41467-023-39054-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023] Open
Abstract
RNA-binding proteins (RBPs) are essential for gene regulation, but it remains a challenge to identify their RNA targets across cell types. Here we present PIE-Seq to investigate Protein-RNA Interaction with dual-deaminase Editing and Sequencing by conjugating C-to-U and A-to-I base editors to RBPs. We benchmark PIE-Seq and demonstrate its sensitivity in single cells, its application in the developing brain, and its scalability with 25 human RBPs. Bulk PIE-Seq identifies canonical binding features for RBPs such as PUM2 and NOVA1, and nominates additional target genes for most tested RBPs such as SRSF1 and TDP-43/TARDBP. Homologous RBPs frequently edit similar sequences and gene sets in PIE-Seq while different RBP families show distinct targets. Single-cell PIE-PUM2 uncovers comparable targets to bulk samples and applying PIE-PUM2 to the developing mouse neocortex identifies neural-progenitor- and neuron-specific target genes such as App. In summary, PIE-Seq provides an orthogonal approach and resource to uncover RBP targets in mice and human cells.
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Affiliation(s)
- Xiangbin Ruan
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Kaining Hu
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Xiaochang Zhang
- Department of Human Genetics and The Neuroscience Institute, University of Chicago, Chicago, IL, USA.
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7
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Nadal M, Anton R, Dorca‐Arévalo J, Estébanez‐Perpiñá E, Tizzano EF, Fuentes‐Prior P. Structure and function analysis of Sam68 and hnRNP A1 synergy in the exclusion of exon 7 from SMN2 transcripts. Protein Sci 2023; 32:e4553. [PMID: 36560896 PMCID: PMC10031812 DOI: 10.1002/pro.4553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/13/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the absence of a functional copy of the Survival of Motor Neuron 1 gene (SMN1). The nearly identical paralog, SMN2, cannot compensate for the loss of SMN1 because exon 7 is aberrantly skipped from most SMN2 transcripts, a process mediated by synergistic activities of Src-associated during mitosis, 68 kDa (Sam68/KHDRBS1) and heterogeneous nuclear ribonucleoprotein (hnRNP) A1. This results in the production of a truncated, nonfunctional protein that is rapidly degraded. Here, we present several crystal structures of Sam68 RNA-binding domain (RBD). Sam68-RBD forms stable symmetric homodimers by antiparallel association of helices α3 from two monomers. However, the details of domain organization and the dimerization interface differ significantly from previously characterized homologs. We demonstrate that Sam68 and hnRNP A1 can simultaneously bind proximal motifs within the central region of SMN2 (ex7). Furthermore, we show that the RNA-binding pockets of the two proteins are close to each other in their heterodimeric complex and identify contact residues using crosslinking-mass spectrometry. We present a model of the ternary Sam68·SMN2 (ex7)·hnRNP A1 complex that reconciles all available information on SMN1/2 splicing. Our findings have important implications for the etiology of SMA and open new avenues for the design of novel therapeutics to treat splicing diseases.
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Affiliation(s)
- Marta Nadal
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
| | - Rosa Anton
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
| | - Jonatan Dorca‐Arévalo
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
- Present address:
Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of BellvitgeHospitalet de Llobregat, University of BarcelonaBarcelonaSpain
| | - Eva Estébanez‐Perpiñá
- Structural Biology of Nuclear Receptors, Department of Biochemistry and Molecular Biomedicine, Faculty of BiologyInstitute of Biomedicine (IBUB) of the University of Barcelona (UB)BarcelonaSpain
| | - Eduardo F. Tizzano
- Medicine Genetics GroupVall d'Hebron Research Institute (VHIR)BarcelonaSpain
- Department of Clinical and Molecular GeneticsHospital Vall d'HebronBarcelonaSpain
| | - Pablo Fuentes‐Prior
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
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8
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Adinolfi A, Di Sante G, Rivignani Vaccari L, Tredicine M, Ria F, Bonvissuto D, Corvino V, Sette C, Geloso MC. Regionally restricted modulation of Sam68 expression and Arhgef9 alternative splicing in the hippocampus of a murine model of multiple sclerosis. Front Mol Neurosci 2023; 15:1073627. [PMID: 36710925 PMCID: PMC9878567 DOI: 10.3389/fnmol.2022.1073627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/21/2022] [Indexed: 01/15/2023] Open
Abstract
Multiple sclerosis (MS) and its preclinical models are characterized by marked changes in neuroplasticity, including excitatory/inhibitory imbalance and synaptic dysfunction that are believed to underlie the progressive cognitive impairment (CI), which represents a significant clinical hallmark of the disease. In this study, we investigated several parameters of neuroplasticity in the hippocampus of the experimental autoimmune encephalomyelitis (EAE) SJL/J mouse model, characterized by rostral inflammatory and demyelinating lesions similar to Relapsing-Remitting MS. By combining morphological and molecular analyses, we found that the hippocampus undergoes extensive inflammation in EAE-mice, more pronounced in the CA3 and dentate gyrus (DG) subfields than in the CA1, associated with changes in GABAergic circuitry, as indicated by the increased expression of the interneuron marker Parvalbumin selectively in CA3. By laser-microdissection, we investigated the impact of EAE on the alternative splicing of Arhgef9, a gene encoding a post-synaptic protein playing an essential role in GABAergic synapses and whose mutations have been related to CI and epilepsy. Our results indicate that EAE induces a specific increase in inclusion of the alternative exon 11a only in the CA3 and DG subfields, in line with the higher local levels of inflammation. Consistently, we found a region-specific downregulation of Sam68, a splicing-factor that represses this splicing event. Collectively, our findings confirm a regionalized distribution of inflammation in the hippocampus of EAE-mice. Moreover, since neuronal circuit rearrangement and dynamic remodeling of structural components of the synapse are key processes that contribute to neuroplasticity, our study suggests potential new molecular players involved in EAE-induced hippocampal dysfunction.
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Affiliation(s)
- Annalisa Adinolfi
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gabriele Di Sante
- Section of Human, Clinic and Forensic Anatomy, Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Luca Rivignani Vaccari
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Tredicine
- Section of General Pathology, Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Francesco Ria
- Section of General Pathology, Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Davide Bonvissuto
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Valentina Corvino
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Claudio Sette
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy,GSTEP-Organoids Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy,*Correspondence: Claudio Sette, ✉
| | - Maria Concetta Geloso
- Section of Human Anatomy, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy,Maria Concetta Geloso, ✉
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Boxer EE, Aoto J. Neurexins and their ligands at inhibitory synapses. Front Synaptic Neurosci 2022; 14:1087238. [PMID: 36618530 PMCID: PMC9812575 DOI: 10.3389/fnsyn.2022.1087238] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/24/2022] [Indexed: 12/24/2022] Open
Abstract
Since the discovery of neurexins (Nrxns) as essential and evolutionarily conserved synaptic adhesion molecules, focus has largely centered on their functional contributions to glutamatergic synapses. Recently, significant advances to our understanding of neurexin function at GABAergic synapses have revealed that neurexins can play pleiotropic roles in regulating inhibitory synapse maintenance and function in a brain-region and synapse-specific manner. GABAergic neurons are incredibly diverse, exhibiting distinct synaptic properties, sites of innervation, neuromodulation, and plasticity. Different classes of GABAergic neurons often express distinct repertoires of Nrxn isoforms that exhibit differential alternative exon usage. Further, Nrxn ligands can be differentially expressed and can display synapse-specific localization patterns, which may contribute to the formation of a complex trans-synaptic molecular code that establishes the properties of inhibitory synapse function and properties of local circuitry. In this review, we will discuss how Nrxns and their ligands sculpt synaptic inhibition in a brain-region, cell-type and synapse-specific manner.
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Affiliation(s)
| | - Jason Aoto
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Denver, CO, United States
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10
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Malki I, Liepina I, Kogelnik N, Watmuff H, Robinson S, Lightfoot A, Gonchar O, Bottrill A, Fry AM, Dominguez C. Cdk1-mediated threonine phosphorylation of Sam68 modulates its RNA binding, alternative splicing activity and cellular functions. Nucleic Acids Res 2022; 50:13045-13062. [PMID: 36537190 PMCID: PMC9825155 DOI: 10.1093/nar/gkac1181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Sam68, also known as KHDRBS1, is a member of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins and its role is modulated by post-translational modifications, including serine/threonine phosphorylation, that differ at various stages of the cell cycle. However, the molecular basis and mechanisms of these modulations remain largely unknown. Here, we combined mass spectrometry, nuclear magnetic resonance spectroscopy and cell biology techniques to provide a comprehensive post-translational modification mapping of Sam68 at different stages of the cell cycle in HEK293 and HCT116 cells. We established that Sam68 is specifically phosphorylated at T33 and T317 by Cdk1, and demonstrated that these phosphorylation events reduce the binding of Sam68 to RNA, control its cellular localization and reduce its alternative splicing activity, leading to a reduction in the induction of apoptosis and an increase in the proliferation of HCT116 cells.
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Affiliation(s)
- Idir Malki
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Inara Liepina
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Nora Kogelnik
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Hollie Watmuff
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Sue Robinson
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Adam Lightfoot
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Oksana Gonchar
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Andrew Bottrill
- Proteomics RTP, School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Andrew M Fry
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Cyril Dominguez
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
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11
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Transcriptome programs involved in the development and structure of the cerebellum. Cell Mol Life Sci 2021; 78:6431-6451. [PMID: 34406416 PMCID: PMC8558292 DOI: 10.1007/s00018-021-03911-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 08/02/2021] [Indexed: 12/23/2022]
Abstract
In the past two decades, mounting evidence has modified the classical view of the cerebellum as a brain region specifically involved in the modulation of motor functions. Indeed, clinical studies and engineered mouse models have highlighted cerebellar circuits implicated in cognitive functions and behavior. Furthermore, it is now clear that insults occurring in specific time windows of cerebellar development can affect cognitive performance later in life and are associated with neurological syndromes, such as Autism Spectrum Disorder. Despite its almost homogenous cytoarchitecture, how cerebellar circuits form and function is not completely elucidated yet. Notably, the apparently simple neuronal organization of the cerebellum, in which Purkinje cells represent the only output, hides an elevated functional diversity even within the same neuronal population. Such complexity is the result of the integration of intrinsic morphogenetic programs and extracellular cues from the surrounding environment, which impact on the regulation of the transcriptome of cerebellar neurons. In this review, we briefly summarize key features of the development and structure of the cerebellum before focusing on the pathways involved in the acquisition of the cerebellar neuron identity. We focus on gene expression and mRNA processing programs, including mRNA methylation, trafficking and splicing, that are set in motion during cerebellar development and participate to its physiology. These programs are likely to add new layers of complexity and versatility that are fundamental for the adaptability of cerebellar neurons.
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12
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Boeckel JN, Möbius-Winkler M, Müller M, Rebs S, Eger N, Schoppe L, Tappu R, Kokot KE, Kneuer JM, Gaul S, Bordalo DM, Lai A, Haas J, Ghanbari M, Drewe-Boss P, Liss M, Katus HA, Ohler U, Gotthardt M, Laufs U, Streckfuss-Bömeke K, Meder B. SLM2 Is A Novel Cardiac Splicing Factor Involved in Heart Failure due to Dilated Cardiomyopathy. GENOMICS PROTEOMICS & BIOINFORMATICS 2021; 20:129-146. [PMID: 34273561 PMCID: PMC9510876 DOI: 10.1016/j.gpb.2021.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/01/2021] [Indexed: 01/09/2023]
Abstract
Alternative mRNA splicing is a fundamental process to increase the versatility of the genome. In humans, cardiac mRNA splicing is involved in the pathophysiology of heart failure. Mutations in the splicing factor RNA binding motif protein 20 (RBM20) cause severe forms of cardiomyopathy. To identify novel cardiomyopathy-associated splicing factors, RNA-seq and tissue-enrichment analyses were performed, which identified up-regulated expression of Sam68-Like mammalian protein 2 (SLM2) in the left ventricle of dilated cardiomyopathy (DCM) patients. In the human heart, SLM2 binds to important transcripts of sarcomere constituents, such as those encoding myosin light chain 2 (MYL2), troponin I3 (TNNI3), troponin T2 (TNNT2), tropomyosin 1/2 (TPM1/2), and titin (TTN). Mechanistically, SLM2 mediates intron retention, prevents exon exclusion, and thereby mediates alternative splicing of the mRNA regions encoding the variable proline-, glutamate-, valine-, and lysine-rich (PEVK) domain and another part of the I-band region of titin. In summary, SLM2 is a novel cardiac splicing regulator with essential functions for maintaining cardiomyocyte integrity by binding to and processing the mRNAs of essential cardiac constituents such as titin.
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Affiliation(s)
- Jes-Niels Boeckel
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; Klinik und Poliklinik für Kardiologie, Universitätskrankenhaus Leipzig, Leipzig 04103, Germany
| | | | - Marion Müller
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany; Clinic for General and Interventional Cardiology/ Angiology, Herz- und Diabeteszentrum NRW, Ruhr-Universität Bochum, Bad Oeynhausen 32545, Germany
| | - Sabine Rebs
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, Goettingen 37075, Germany; German Center for Cardiovascular Research (DZHK), Partner site Goettingen, Goettingen 37075, Germany
| | - Nicole Eger
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Laura Schoppe
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Rewati Tappu
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Karoline E Kokot
- Klinik und Poliklinik für Kardiologie, Universitätskrankenhaus Leipzig, Leipzig 04103, Germany
| | - Jasmin M Kneuer
- Klinik und Poliklinik für Kardiologie, Universitätskrankenhaus Leipzig, Leipzig 04103, Germany
| | - Susanne Gaul
- Klinik und Poliklinik für Kardiologie, Universitätskrankenhaus Leipzig, Leipzig 04103, Germany
| | - Diana M Bordalo
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany
| | - Alan Lai
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany
| | - Jan Haas
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany
| | - Mahsa Ghanbari
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 10115, Germany; Institute of Biology, Humboldt Universität zu Berlin, Berlin 10099, Germany
| | - Philipp Drewe-Boss
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 10115, Germany; Institute of Biology, Humboldt Universität zu Berlin, Berlin 10099, Germany
| | - Martin Liss
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13092, Germany; German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin 10117, Germany
| | - Hugo A Katus
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 10115, Germany; Institute of Biology, Humboldt Universität zu Berlin, Berlin 10099, Germany
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13092, Germany; German Center for Cardiovascular Research (DZHK), Partner site Berlin, Berlin 10117, Germany
| | - Ulrich Laufs
- Klinik und Poliklinik für Kardiologie, Universitätskrankenhaus Leipzig, Leipzig 04103, Germany
| | - Katrin Streckfuss-Bömeke
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, Goettingen 37075, Germany; German Center for Cardiovascular Research (DZHK), Partner site Goettingen, Goettingen 37075, Germany
| | - Benjamin Meder
- Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Heidelberg 69120, Germany; German Center for Cardiovascular Research (DZHK), Partner site Heidelberg, Heidelberg 69120, Germany; Stanford Genome Technology Center, Department of Genetics, Stanford Medical School, Palo Alto, CA 94304, USA.
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13
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Distinct Expression of SLM2 Underlies Splicing-Dependent Trans-Synaptic Signaling of Neurexin Across GABAergic Neuron Subtypes. Neurochem Res 2021; 47:2591-2601. [PMID: 34196888 DOI: 10.1007/s11064-021-03384-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/25/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
The mammalian brain contains multiple types of neuronal cells with complex assemblies and distinct structural and functional properties encoded by divergent gene programs. There is increasing evidence that alternative splicing (AS) plays fundamental roles in transcriptomic diversity and specifying synaptic properties of each neuronal cell type. However, the mechanisms underlying AS regulation and whether it controls synapse formation across GABAergic interneurons have not been fully elucidated. Here we show the differential expression levels of Sam68-like molecule 2 (SLM2), a major splicing regulator of neurexin (NRX), in GABAergic neuronal subtypes and its contribution to GABAergic synapse specification. Cortical SLM2 is strongly expressed not only in excitatory neurons but also in a subpopulation of GABAergic interneurons, especially in VIP-positive neurons that are originated from late-born caudal ganglionic eminence (GE)- derived cells. Using artificial synapse formation assay, we found that GE containing cortices form a strong synapse with LRRTM2, a trans-synaptic receptor of the alternatively spliced segment 4 (AS4)(-) of NRX. SLM2 knock-down reduced the NRX AS4(-) isoform expression and hence weaken LRRTM2-induced synapse formation. The addition of NRX AS4(-) was sufficient to rescue the synaptic formation by LRRTM2 in SLM2 knock-down neurons. Thus, our findings suggest a novel function of SLM2 in modifying network formation of a specific population of GABAergic interneurons and contribute to a better understanding of the roles AS plays in regulating synapse specificity and neuronal molecular diversity.
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14
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Aerobic Exercise Induces Alternative Splicing of Neurexins in Frontal Cortex. J Funct Morphol Kinesiol 2021; 6:jfmk6020048. [PMID: 34072692 PMCID: PMC8261640 DOI: 10.3390/jfmk6020048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/02/2022] Open
Abstract
Aerobic exercise (AE) is known to produce beneficial effects on brain health by improving plasticity, connectivity, and cognitive functions, but the underlying molecular mechanisms are still limited. Neurexins (Nrxns) are a family of presynaptic cell adhesion molecules that are important in synapsis formation and maturation. In vertebrates, three-neurexin genes (NRXN1, NRXN2, and NRXN3) have been identified, each encoding for α and β neurexins, from two independent promoters. Moreover, each Nrxns gene (1-3) has several alternative exons and produces many splice variants that bind to a large variety of postsynaptic ligands, playing a role in trans-synaptic specification, strength, and plasticity. In this study, we investigated the impact of a continuous progressive (CP) AE program on alternative splicing (AS) of Nrxns on two brain regions: frontal cortex (FC) and hippocampus. We showed that exercise promoted Nrxns1-3 AS at splice site 4 (SS4) both in α and β isoforms, inducing a switch from exon-excluded isoforms (SS4-) to exon-included isoforms (SS4+) in FC but not in hippocampus. Additionally, we showed that the same AE program enhanced the expression level of other genes correlated with synaptic function and plasticity only in FC. Altogether, our findings demonstrated the positive effect of CP AE on FC in inducing molecular changes underlying synaptic plasticity and suggested that FC is possibly a more sensitive structure than hippocampus to show molecular changes.
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15
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Andrews PC, Dravid SM. An emerging map of glutamate delta 1 receptors in the forebrain. Neuropharmacology 2021; 192:108587. [PMID: 33992669 DOI: 10.1016/j.neuropharm.2021.108587] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/15/2021] [Accepted: 04/20/2021] [Indexed: 11/19/2022]
Abstract
Glutamate delta 1 (GluD1) and glutamate delta 2 (GluD2) form the delta family of ionotropic glutamate receptors; these proteins plays widespread roles in synaptic architecture, motor behavior, and cognitive function. Though the role of GluD2 at cerebellar parallel fiber-Purkinje cell synapses is well established, attention now turns to the function of GluD receptors in the forebrain. GluD1 regulates synaptic assembly and modulation in multiple higher brain regions, acting as a postsynaptic cell adhesion molecule with effects on both excitatory and inhibitory transmission. Furthermore, variations and mutations in the GRID1 gene, which codes for GluD1, and in genes which code for proteins functionally linked to GluD1, are associated with mental disorders including autism, schizophrenia, bipolar disorder, and major depression. Cerebellin (Cbln) family proteins, the primary binding partners of delta receptors, are secreted C1q-like proteins which also bind presynaptic neurexins (NRXNs), forming a tripartite synaptic bridge. Published research explores this bridge's function in regions including the striatum, hippocampus, cortex, and cerebellum. In this review, we summarize region- and circuit-specific functions and expression patterns for GluD1 and its related proteins, and their implications for behavior and disease.
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Affiliation(s)
- Patrick C Andrews
- Department of Pharmacology and Neuroscience, Creighton University, 2500 California Plaza, Omaha, NE, USA
| | - Shashank M Dravid
- Department of Pharmacology and Neuroscience, Creighton University, 2500 California Plaza, Omaha, NE, USA.
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16
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Farini D, Cesari E, Weatheritt RJ, La Sala G, Naro C, Pagliarini V, Bonvissuto D, Medici V, Guerra M, Di Pietro C, Rizzo FR, Musella A, Carola V, Centonze D, Blencowe BJ, Marazziti D, Sette C. A Dynamic Splicing Program Ensures Proper Synaptic Connections in the Developing Cerebellum. Cell Rep 2021; 31:107703. [PMID: 32492419 DOI: 10.1016/j.celrep.2020.107703] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/13/2020] [Accepted: 05/07/2020] [Indexed: 12/14/2022] Open
Abstract
Tight coordination of gene expression in the developing cerebellum is crucial for establishment of neuronal circuits governing motor and cognitive function. However, transcriptional changes alone do not explain all of the switches underlying neuronal differentiation. Here we unveiled a widespread and highly dynamic splicing program that affects synaptic genes in cerebellar neurons. The motifs enriched in modulated exons implicated the splicing factor Sam68 as a regulator of this program. Sam68 controls splicing of exons with weak branchpoints by directly binding near the 3' splice site and competing with U2AF recruitment. Ablation of Sam68 disrupts splicing regulation of synaptic genes associated with neurodevelopmental diseases and impairs synaptic connections and firing of Purkinje cells, resulting in motor coordination defects, ataxia, and abnormal social behavior. These findings uncover an unexpectedly dynamic splicing regulatory network that shapes the synapse in early life and establishes motor and cognitive circuitry in the developing cerebellum.
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Affiliation(s)
- Donatella Farini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy; Fondazione Santa Lucia, IRCCS, Rome, Italy
| | - Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Robert J Weatheritt
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada; EMBL Australia, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Gina La Sala
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Davide Bonvissuto
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy
| | - Vanessa Medici
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy; Fondazione Santa Lucia, IRCCS, Rome, Italy
| | - Marika Guerra
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Chiara Di Pietro
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Francesca Romana Rizzo
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; San Raffaele Pisana and University San Raffaele, IRCCS, Rome, Italy
| | | | - Valeria Carola
- Fondazione Santa Lucia, IRCCS, Rome, Italy; Department of Dynamic and Clinical Psychology, University of Rome Sapienza, Rome, Italy
| | - Diego Centonze
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; Unit of Neurology, IRCCS Neuromed, Pozzilli, Isernia, Italy
| | - Benjamin J Blencowe
- Donnelly Centre and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Daniela Marazziti
- Institute of Cell Biology and Neurobiology, CNR, Monterotondo, Rome, Italy
| | - Claudio Sette
- Fondazione Santa Lucia, IRCCS, Rome, Italy; Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy.
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17
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Abstract
The function of neuronal circuits relies on the properties of individual neuronal cells and their synapses. We propose that a substantial degree of synapse formation and function is instructed by molecular codes resulting from transcriptional programmes. Recent studies on the Neurexin protein family and its ligands provide fundamental insight into how synapses are assembled and remodelled, how synaptic properties are specified and how single gene mutations associated with neurodevelopmental and psychiatric disorders might modify the operation of neuronal circuits and behaviour. In this Review, we first summarize insights into Neurexin function obtained from various model organisms. We then discuss the mechanisms and logic of the cell type-specific regulation of Neurexin isoforms, in particular at the level of alternative mRNA splicing. Finally, we propose a conceptual framework for how combinations of synaptic protein isoforms act as 'senders' and 'readers' to instruct synapse formation and the acquisition of cell type-specific and synapse-specific functional properties.
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18
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Naro C, Cesari E, Sette C. Splicing regulation in brain and testis: common themes for highly specialized organs. Cell Cycle 2021; 20:480-489. [PMID: 33632061 PMCID: PMC8018374 DOI: 10.1080/15384101.2021.1889187] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/17/2021] [Accepted: 02/07/2021] [Indexed: 12/26/2022] Open
Abstract
Expansion of the coding and regulatory capabilities of eukaryotic transcriptomes by alternative splicing represents one of the evolutionary forces underlying the increased structural complexity of metazoans. Brain and testes stand out as the organs that mostly exploit the potential of alternative splicing, thereby expressing the largest repertoire of splice variants. Herein, we will review organ-specific as well as common mechanisms underlying the high transcriptome complexity of these organs and discuss the impact exerted by this widespread alternative splicing regulation on the functionality and differentiation of brain and testicular cells.
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Affiliation(s)
- Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy
| | - Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, Rome, Italy
- Laboratory of Neuroembryology, IRCCS Fondazione Santa Lucia, Rome, Italy
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19
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Marchese E, Valentini M, Di Sante G, Cesari E, Adinolfi A, Corvino V, Ria F, Sette C, Geloso MC. Alternative splicing of neurexins 1-3 is modulated by neuroinflammation in the prefrontal cortex of a murine model of multiple sclerosis. Exp Neurol 2020; 335:113497. [PMID: 33058888 DOI: 10.1016/j.expneurol.2020.113497] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/21/2020] [Accepted: 10/06/2020] [Indexed: 12/23/2022]
Abstract
Mounting evidence points to immune-mediated synaptopathy and impaired plasticity as early pathogenic events underlying cognitive decline (CD) in Multiple sclerosis (MS) and in the experimental autoimmune encephalomyelitis (EAE) mouse model of the disease. However, knowledge of the neurobiology of synaptic dysfunction is still incomplete. Splicing regulation represents a flexible and powerful mechanism involved in dynamic remodeling of the synapse, which allows the expression of synaptic protein variants that dynamically control the specificity of contacts between neurons. The pre-synaptic adhesion molecules neurexins (NRXNs) 1-3 play a relevant role in cognition and are alternatively spliced to yield variants that differentially cluster specific ligands in the postsynaptic compartment and modulate functional properties of the synaptic contact. Notably, mutations in these genes or disruption of their splicing program are associated with neuropsychiatric disorders. Herein, we have investigated how inflammatory changes imposed by EAE impact on alternative splicing of the Nrxn 1-3 mouse genes in the acute phase of disease. Due to its relevance in cognition, we focused on the prefrontal cortex (PFC) of SJL/J mice, in which EAE-induced inflammatory lesions extend to the rostral forebrain. We found that inclusion of the Nrxn 1-3 AS4 exon is significantly increased in the PFC of EAE mice and that splicing changes are correlated with local Il1β-expression levels. This correlation is sustained by the concomitant downregulation of SLM2, the main splicing factor involved in skipping of the AS4 exon, in EAE mice displaying high levels of Il1β- expression. We also observed that Il1β-expression levels correlate with changes in parvalbumin (PV)-positive interneuron connectivity. Moreover, exposure to environmental enrichment (EE), a condition known to stimulate neuronal connectivity and to improve cognitive functions in mice and humans, modified PFC phenotypes of EAE mice with respect to Il1β-, Slm2-expression, Nrxn AS4 splicing and PV-expression, by limiting changes associated with high levels of inflammation. Our results reveal that local inflammation results in early splicing modulation of key synaptic proteins and in remodeling of GABAergic circuitry in the PFC of SJL/J mice. We also suggest EE as a tool to counteract these inflammation-associated events, thus highlighting potential therapeutic targets for limiting the progressive CD occurring in MS.
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Affiliation(s)
- Elisa Marchese
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
| | - Mariagrazia Valentini
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
| | - Gabriele Di Sante
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 1-8, 00168 Rome, Italy.
| | - Eleonora Cesari
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; IRCCS Santa Lucia Foundation, Via del Fosso di Fiorano 65, 00143 Rome, Italy.
| | - Annalisa Adinolfi
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
| | - Valentina Corvino
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
| | - Francesco Ria
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo Agostino Gemelli 1-8, 00168 Rome, Italy.
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
| | - Maria Concetta Geloso
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
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20
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Zhang Y, Yang HT, Kadash-Edmondson K, Pan Y, Pan Z, Davidson BL, Xing Y. Regional Variation of Splicing QTLs in Human Brain. Am J Hum Genet 2020; 107:196-210. [PMID: 32589925 PMCID: PMC7413857 DOI: 10.1016/j.ajhg.2020.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/02/2020] [Indexed: 12/31/2022] Open
Abstract
A major question in human genetics is how sequence variants of broadly expressed genes produce tissue- and cell type-specific molecular phenotypes. Genetic variation of alternative splicing is a prevalent source of transcriptomic and proteomic diversity in human populations. We investigated splicing quantitative trait loci (sQTLs) in 1,209 samples from 13 human brain regions, using RNA sequencing (RNA-seq) and genotype data from the Genotype-Tissue Expression (GTEx) project. Hundreds of sQTLs were identified in each brain region. Some sQTLs were shared across brain regions, whereas others displayed regional specificity. These “regionally ubiquitous” and “regionally specific” sQTLs showed distinct positional distributions of single-nucleotide polymorphisms (SNPs) within and outside essential splice sites, respectively, suggesting their regulation by distinct molecular mechanisms. Integrating the binding motifs and expression patterns of RNA binding proteins with exon splicing profiles, we uncovered likely causal variants underlying brain region-specific sQTLs. Notably, SNP rs17651213 created a putative binding site for the splicing factor RBFOX2 and was associated with increased splicing of MAPT exon 3 in cerebellar tissues, where RBFOX2 was highly expressed. Overall, our study reveals a more comprehensive spectrum and regional variation of sQTLs in human brain and demonstrates that such regional variation can be used to fine map potential causal variants of sQTLs and their associated neurological diseases.
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Affiliation(s)
- Yida Zhang
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Harry Taegyun Yang
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kathryn Kadash-Edmondson
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Yang Pan
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Zhicheng Pan
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Beverly L Davidson
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi Xing
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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21
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Gòdia M, Castelló A, Rocco M, Cabrera B, Rodríguez-Gil JE, Balasch S, Lewis C, Sánchez A, Clop A. Identification of circular RNAs in porcine sperm and evaluation of their relation to sperm motility. Sci Rep 2020; 10:7985. [PMID: 32409652 PMCID: PMC7224279 DOI: 10.1038/s41598-020-64711-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/13/2020] [Indexed: 12/16/2022] Open
Abstract
Circular RNAs (circRNAs) are emerging as a novel class of noncoding RNAs which potential role as gene regulators is quickly gaining interest. circRNAs have been studied in different tissues and cell types across several animal species. However, a thorough characterization of the circRNAome in ejaculated sperm remains unexplored. In this study, we profiled the sperm circRNA catalogue using 40 porcine ejaculates. A complex population of 1,598 circRNAs was shared in at least 30 of the 40 samples. Generally speaking, the predicted circRNAs presented low abundances and were tissue-specific. Around 80% of the circRNAs identified in the boar sperm were reported as novel. Results from abundance correlation between circRNAs and miRNAs together with the prediction of microRNA (miRNA) target sites in circRNAs suggested that circRNAs may act as miRNA sponges. Moreover, we found significant correlations between the abundance of 148 exonic circRNAs and sperm motility parameters. Two of these correlations, involving ssc_circ_1458 and ssc_circ_1321, were confirmed by RT-qPCR using 36 additional samples with extreme and opposite sperm motility values. Our study provides a thorough characterization of circRNAs in sperm and suggests that circRNAs hold potential as noninvasive biomarkers for sperm quality and male fertility.
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Affiliation(s)
- Marta Gòdia
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Anna Castelló
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain.,Unit of Animal Science, Department of Animal and Food Science, Autonomous University of Barcelona, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Martina Rocco
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain.,Unit of Animal Reproduction, Department of Animal Medicine and Surgery, Autonomous University of Barcelona, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Betlem Cabrera
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain.,Unit of Animal Science, Department of Animal and Food Science, Autonomous University of Barcelona, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Joan Enric Rodríguez-Gil
- Unit of Animal Reproduction, Department of Animal Medicine and Surgery, Autonomous University of Barcelona, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Sam Balasch
- Grup Gepork S.A., Barcelona, Catalonia, Spain
| | - Craig Lewis
- PIC Europe, Sant Cugat del Vallés, Catalonia, Spain
| | - Armand Sánchez
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain.,Unit of Animal Science, Department of Animal and Food Science, Autonomous University of Barcelona, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Alex Clop
- Animal Genomics Group, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB, Cerdanyola del Vallès, Barcelona, Catalonia, Spain. .,Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Catalonia, Spain.
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22
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Park H, Choi Y, Jung H, Kim S, Lee S, Han H, Kweon H, Kang S, Sim WS, Koopmans F, Yang E, Kim H, Smit AB, Bae YC, Kim E. Splice-dependent trans-synaptic PTPδ-IL1RAPL1 interaction regulates synapse formation and non-REM sleep. EMBO J 2020; 39:e104150. [PMID: 32347567 PMCID: PMC7265247 DOI: 10.15252/embj.2019104150] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/17/2020] [Accepted: 03/23/2020] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing regulates trans‐synaptic adhesions and synapse development, but supporting in vivo evidence is limited. PTPδ, a receptor tyrosine phosphatase adhering to multiple synaptic adhesion molecules, is associated with various neuropsychiatric disorders; however, its in vivo functions remain unclear. Here, we show that PTPδ is mainly present at excitatory presynaptic sites by endogenous PTPδ tagging. Global PTPδ deletion in mice leads to input‐specific decreases in excitatory synapse development and strength. This involves tyrosine dephosphorylation and synaptic loss of IL1RAPL1, a postsynaptic partner of PTPδ requiring the PTPδ‐meA splice insert for binding. Importantly, PTPδ‐mutant mice lacking the PTPδ‐meA insert, and thus lacking the PTPδ interaction with IL1RAPL1 but not other postsynaptic partners, recapitulate biochemical and synaptic phenotypes of global PTPδ‐mutant mice. Behaviorally, both global and meA‐specific PTPδ‐mutant mice display abnormal sleep behavior and non‐REM rhythms. Therefore, alternative splicing in PTPδ regulates excitatory synapse development and sleep by modulating a specific trans‐synaptic adhesion.
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Affiliation(s)
- Haram Park
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Yeonsoo Choi
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hwajin Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Seoyeong Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hyemin Han
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Hanseul Kweon
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suwon Kang
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Woong Seob Sim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Frank Koopmans
- Department of Functional Genomics, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands.,Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea.,Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
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23
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Iijima Y, Tanaka M, Suzuki S, Hauser D, Tanaka M, Okada C, Ito M, Ayukawa N, Sato Y, Ohtsuka M, Scheiffele P, Iijima T. SAM68-Specific Splicing Is Required for Proper Selection of Alternative 3' UTR Isoforms in the Nervous System. iScience 2019; 22:318-335. [PMID: 31805436 PMCID: PMC6909182 DOI: 10.1016/j.isci.2019.11.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/09/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022] Open
Abstract
Neuronal alternative splicing is a core mechanism for functional diversification. We previously found that STAR family proteins (SAM68, SLM1, SLM2) regulate spatiotemporal alternative splicing in the nervous system. However, the whole aspect of alternative splicing programs by STARs remains unclear. Here, we performed a transcriptomic analysis using SAM68 knockout and SAM68/SLM1 double-knockout midbrains. We revealed different alternative splicing activity between SAM68 and SLM1; SAM68 preferentially targets alternative 3′ UTR exons. SAM68 knockout causes a long-to-short isoform switch of a number of neuronal targets through the alteration in alternative last exon (ALE) selection or alternative polyadenylation. The altered ALE usage of a novel target, interleukin 1 receptor accessory protein (Il1rap), results in remarkable conversion from a membrane-bound type to a secreted type in Sam68KO brains. Proper ALE selection is necessary for IL1RAP neuronal function. Thus the SAM68-specific splicing program provides a mechanism for neuronal selection of alternative 3′ UTR isoforms. SAM68 and the related protein SLM1 exhibit distinct alternative splicing activity SAM68 specifically controls 3′ UTR selection of multiple neuronal genes Proper 3′ UTR selection is necessary for IL1RAP neuronal function Neuronal expression of SAM68 requires proper 3′ UTR selection in the nervous system
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Affiliation(s)
- Yoko Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, 143, Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Masami Tanaka
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Satoko Suzuki
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - David Hauser
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, Basel 4056, Switzerland
| | - Masayuki Tanaka
- The Support Center for Medical Research and Education, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Chisa Okada
- The Support Center for Medical Research and Education, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Masatoshi Ito
- The Support Center for Medical Research and Education, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Noriko Ayukawa
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Yuji Sato
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, 143, Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Masato Ohtsuka
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, 143, Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Peter Scheiffele
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, Basel 4056, Switzerland
| | - Takatoshi Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, 143, Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
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24
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Yan T, Ding F, Zhao Y. Integrated identification of key genes and pathways in Alzheimer's disease via comprehensive bioinformatical analyses. Hereditas 2019; 156:25. [PMID: 31346329 PMCID: PMC6636172 DOI: 10.1186/s41065-019-0101-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/09/2019] [Indexed: 12/23/2022] Open
Abstract
Background Alzheimer's disease (AD) is known to be caused by multiple factors, meanwhile the pathogenic mechanism and development of AD associate closely with genetic factors. Existing understanding of the molecular mechanisms underlying AD remains incomplete. Methods Gene expression data (GSE48350) derived from post-modern brain was extracted from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were derived from hippocampus and entorhinal cortex regions between AD patients and healthy controls and detected via Morpheus. Functional enrichment analyses, including Gene Ontology (GO) and pathway analyses of DEGs, were performed via Cytoscape and followed by the construction of protein-protein interaction (PPI) network. Hub proteins were screened using the criteria: nodes degree≥10 (for hippocampus tissues) and ≥ 8 (for entorhinal cortex tissues). Molecular Complex Detection (MCODE) was used to filtrate the important clusters. University of California Santa Cruz (UCSC) and the database of RNA-binding protein specificities (RBPDB) were employed to identify the RNA-binding proteins of the long non-coding RNA (lncRNA). Results 251 & 74 genes were identified as DEGs, which consisted of 56 & 16 up-regulated genes and 195 & 58 down-regulated genes in hippocampus and entorhinal cortex, respectively. Biological analyses demonstrated that the biological processes and pathways related to memory, transmembrane transport, synaptic transmission, neuron survival, drug metabolism, ion homeostasis and signal transduction were enriched in these genes. 11 genes were identified as hub genes in hippocampus and entorhinal cortex, and 3 hub genes were identified as the novel candidates involved in the pathology of AD. Furthermore, 3 lncRNAs were filtrated, whose binding proteins were closely associated with AD. Conclusions Through GO enrichment analyses, pathway analyses and PPI analyses, we showed a comprehensive interpretation of the pathogenesis of AD at a systematic biology level, and 3 novel candidate genes and 3 lncRNAs were identified as novel and potential candidates participating in the pathology of AD. The results of this study could supply integrated insights for understanding the pathogenic mechanism underlying AD and potential novel therapeutic targets.
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Affiliation(s)
- Tingting Yan
- Department of Bioengineering, Harbin Institute of Technology, Weihai, 264209 Shandong China
| | - Feng Ding
- Department of Bioengineering, Harbin Institute of Technology, Weihai, 264209 Shandong China
| | - Yan Zhao
- Department of Bioengineering, Harbin Institute of Technology, Weihai, 264209 Shandong China
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25
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Dai J, Aoto J, Südhof TC. Alternative Splicing of Presynaptic Neurexins Differentially Controls Postsynaptic NMDA and AMPA Receptor Responses. Neuron 2019; 102:993-1008.e5. [PMID: 31005376 PMCID: PMC6554035 DOI: 10.1016/j.neuron.2019.03.032] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/20/2019] [Accepted: 03/19/2019] [Indexed: 12/11/2022]
Abstract
AMPA- and NMDA-type glutamate receptors mediate distinct postsynaptic signals that differ characteristically among synapses. How postsynaptic AMPA- and NMDA-receptor levels are regulated, however, remains unclear. Using newly generated conditional knockin mice that enable genetic control of neurexin alternative splicing, we show that in hippocampal synapses, alternative splicing of presynaptic neurexin-1 at splice site 4 (SS4) dramatically enhanced postsynaptic NMDA-receptor-mediated, but not AMPA-receptor-mediated, synaptic responses without altering synapse density. In contrast, alternative splicing of neurexin-3 at SS4 suppressed AMPA-receptor-mediated, but not NMDA-receptor-mediated, synaptic responses, while alternative splicing of neurexin-2 at SS4 had no effect on NMDA- or AMPA-receptor-mediated responses. Presynaptic overexpression of the neurexin-1β and neurexin-3β SS4+ splice variants, but not of their SS4- splice variants, replicated the respective SS4+ knockin phenotypes. Thus, different neurexins perform distinct nonoverlapping functions at hippocampal synapses that are independently regulated by alternative splicing. These functions transsynaptically control NMDA and AMPA receptors, thereby mediating presynaptic control of postsynaptic responses.
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Affiliation(s)
- Jinye Dai
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jason Aoto
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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26
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A genome-wide association study of tramadol metabolism from post-mortem samples. THE PHARMACOGENOMICS JOURNAL 2019; 20:94-103. [PMID: 30971809 DOI: 10.1038/s41397-019-0088-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 01/08/2019] [Accepted: 03/27/2019] [Indexed: 11/09/2022]
Abstract
Phase I tramadol metabolism requires cytochrome p450 family 2, subfamily D, polypeptide 6 (CYP2D6) to form O-desmethyltramadol (M1). CYP2D6 genetic variants may infer metabolizer phenotype; however, drug ADME (absorption, distribution, metabolism, and excretion) and response depend on protein pathway(s), not CYP2D6 alone. There is a paucity of data regarding the contribution of trans-acting proteins to idiosyncratic phenotypes following drug exposure. A genome-wide association study identified five markers (rs79983226/kgp11274252, rs9384825, rs62435418/kgp10370907, rs72732317/kgp3743668, and rs184199168/exm1592932) associated with the conversion of tramadol to M1 (M1:T). These SNPs reside within five genes previously implicated with adverse reactions. Analysis of accompanying toxicological meta-data revealed a significant positive linear relationship between M1:T and degree of sample polypharmacy. Taken together, these data identify candidate loci for potential clinical inferences of phenotype following exposure to tramadol and highlight sample polypharmacy as a possible diagnostic covariate in post-mortem genetic studies.
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27
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Witte H, Schreiner D, Scheiffele P. A Sam68-dependent alternative splicing program shapes postsynaptic protein complexes. Eur J Neurosci 2019; 49:1436-1453. [PMID: 30589479 DOI: 10.1111/ejn.14332] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 12/30/2022]
Abstract
Alternative splicing is one of the key mechanisms to increase the diversity of cellular transcriptomes, thereby expanding the coding capacity of the genome. This diversity is of particular importance in the nervous system with its elaborated cellular networks. Sam68, a member of the Signal Transduction Associated RNA-binding (STAR) family of RNA-binding proteins, is expressed in the developing and mature nervous system but its neuronal functions are poorly understood. Here, we perform genome-wide mapping of the Sam68-dependent alternative splicing program in mice. We find that Sam68 is required for the regulation of a set of alternative splicing events in pre-mRNAs encoding several postsynaptic scaffolding molecules that are central to the function of GABAergic and glutamatergic synapses. These components include Collybistin (Arhgef9), Gephyrin (Gphn), and Densin-180 (Lrrc7). Sam68-regulated Lrrc7 variants engage in differential protein interactions with signalling proteins, thus, highlighting a contribution of the Sam68 splicing program to shaping synaptic complexes. These findings suggest an important role for Sam68-dependent alternative splicing in the regulation of synapses in the central nervous system.
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Affiliation(s)
- Harald Witte
- Biozentrum of the University of Basel, Basel, Switzerland
| | - Dietmar Schreiner
- Biozentrum of the University of Basel, Basel, Switzerland.,Institute of Neuroanatomy and Cell Biology, Hannover, Germany
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28
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Furlanis E, Scheiffele P. Regulation of Neuronal Differentiation, Function, and Plasticity by Alternative Splicing. Annu Rev Cell Dev Biol 2018; 34:451-469. [PMID: 30028642 DOI: 10.1146/annurev-cellbio-100617-062826] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Posttranscriptional mechanisms provide powerful means to expand the coding power of genomes. In nervous systems, alternative splicing has emerged as a fundamental mechanism not only for the diversification of protein isoforms but also for the spatiotemporal control of transcripts. Thus, alternative splicing programs play instructive roles in the development of neuronal cell type-specific properties, neuronal growth, self-recognition, synapse specification, and neuronal network function. Here we discuss the most recent genome-wide efforts on mapping RNA codes and RNA-binding proteins for neuronal alternative splicing regulation. We illustrate how alternative splicing shapes key steps of neuronal development, neuronal maturation, and synaptic properties. Finally, we highlight efforts to dissect the spatiotemporal dynamics of alternative splicing and their potential contribution to neuronal plasticity and the mature nervous system.
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29
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Li N, Ngo CTA, Aleynikova O, Beauchemin N, Richard S. The p53 status can influence the role of Sam68 in tumorigenesis. Oncotarget 2018; 7:71651-71659. [PMID: 27690217 PMCID: PMC5342108 DOI: 10.18632/oncotarget.12305] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/20/2016] [Indexed: 02/02/2023] Open
Abstract
The expression and activities of RNA binding proteins are frequently dysregulated in human cancer. Their roles, however, appears to be complex, with reports indicating both pro-tumorigenic and tumor suppressive functions. Here we show, using two classical mouse cancer models, that the role of KH-type RNA binding protein, Sam68, in tumor development can be influenced by the status of the p53 tumor suppressor. We demonstrate that in mice expressing wild type p53, Sam68-deficiency resulted in a higher incidence and malignancy of carcinogen-induced tumors, suggesting a tumor suppressive role for Sam68. In marked contrast, Sam68-haploinsufficiency significantly delayed the onset of tumors in mice lacking p53 and prolonged their survival, indicating that Sam68 accelerates the development of p53-deficient tumors. These findings provide considerable insight into a previously unknown relationship between Sam68 and the p53 tumor suppressor in tumorigenesis.
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Affiliation(s)
- Naomi Li
- Terry Fox Molecular Oncology Group and the Bloomfield Center for Research on Aging, Sir Mortimer B Davis Jewish General Hospital, Lady Davis Institute for Medical Research, Montréal, Québec H3T 1E2, Canada.,Department of Medicine and Oncology, McGill University, Montréal, Québec H3A 1A1, Canada
| | - Chau Tuan-Anh Ngo
- Terry Fox Molecular Oncology Group and the Bloomfield Center for Research on Aging, Sir Mortimer B Davis Jewish General Hospital, Lady Davis Institute for Medical Research, Montréal, Québec H3T 1E2, Canada.,Department of Medicine and Oncology, McGill University, Montréal, Québec H3A 1A1, Canada
| | - Olga Aleynikova
- Department of Pathology, Jewish General Hospital, Montréal, Québec H3T 1E2, Canada
| | - Nicole Beauchemin
- Department of Medicine and Oncology, McGill University, Montréal, Québec H3A 1A1, Canada.,Department of Biochemistry, McGill University, Montréal, Québec H3G 1Y6, Canada.,Rosalind and Morris Goodman Cancer Centre, Montréal, Québec H3A 1A3, Canada
| | - Stéphane Richard
- Terry Fox Molecular Oncology Group and the Bloomfield Center for Research on Aging, Sir Mortimer B Davis Jewish General Hospital, Lady Davis Institute for Medical Research, Montréal, Québec H3T 1E2, Canada.,Department of Medicine and Oncology, McGill University, Montréal, Québec H3A 1A1, Canada
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30
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Post-Transcriptional Regulation of Anti-Apoptotic BCL2 Family Members. Int J Mol Sci 2018; 19:ijms19010308. [PMID: 29361709 PMCID: PMC5796252 DOI: 10.3390/ijms19010308] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
Anti-apoptotic B cell lymphoma 2 (BCL2) family members (BCL2, MCL1, BCLxL, BCLW, and BFL1) are key players in the regulation of intrinsic apoptosis. Dysregulation of these proteins not only impairs normal development, but also contributes to tumor progression and resistance to various anti-cancer therapies. Therefore, cells maintain strict control over the expression of anti-apoptotic BCL2 family members using multiple mechanisms. Over the past two decades, the importance of post-transcriptional regulation of mRNA in controlling gene expression and its impact on normal homeostasis and disease have begun to be appreciated. In this review, we discuss the RNA binding proteins (RBPs) and microRNAs (miRNAs) that mediate post-transcriptional regulation of the anti-apoptotic BCL2 family members. We describe their roles and impact on alternative splicing, mRNA turnover, and mRNA subcellular localization. We also point out the importance of future studies in characterizing the crosstalk between RBPs and miRNAs in regulating anti-apoptotic BCL2 family member expression and ultimately apoptosis.
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31
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Wang S, Yang Q, Wang Z, Feng S, Li H, Ji D, Zhang S. Evolutionary and Expression Analyses Show Co-option of khdrbs Genes for Origin of Vertebrate Brain. Front Genet 2018; 8:225. [PMID: 29354154 PMCID: PMC5758493 DOI: 10.3389/fgene.2017.00225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 12/15/2017] [Indexed: 11/13/2022] Open
Abstract
Genes generated by whole genome duplications (WGD) can be co-opted by changing their regulation process or altering their coding proteins, which has been shown contributable to the emergence of vertebrate morphological novelties such as vertebrate cartilage. Mouse khdrbs genes, differing from its invertebrate orthologs, were mainly expressed in brain, hinting that khdrbs gene family as a member of genetic toolkit may be linked to vertebrate brain development. However, the evolutionary relationship between khdrbs gene family and vertebrate brain development is unclear. First, we analyzed the evolutionary history of khdrbs gene family in metazoans, and then investigated their expression patterns during early development and in adulthood of zebrafish. We found that the duplication of khdrbs gene family by WGD took place in zebrafish, and all zebrafish khdrbs genes were predominantly expressed in the substructures of brain during early development. Given the expression of invertebrate khdrbs gene in germ line, the distinct expression domains of zebrafish khdrbs genes in brain suggested that the duplicated khdrbs genes are co-opted for promoting the evolutionary origin of vertebrate brain.
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Affiliation(s)
- Su Wang
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Qingyun Yang
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Ziyue Wang
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Shuoqi Feng
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Hongyan Li
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Dongrui Ji
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
| | - Shicui Zhang
- Laboratory for Evolution and Development, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.,Laboratory for Evolution and Development, Department of Marine Biology, Ocean University of China, Qingdao, China
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32
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Südhof TC. Synaptic Neurexin Complexes: A Molecular Code for the Logic of Neural Circuits. Cell 2017; 171:745-769. [PMID: 29100073 DOI: 10.1016/j.cell.2017.10.024] [Citation(s) in RCA: 462] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/04/2017] [Accepted: 10/15/2017] [Indexed: 10/18/2022]
Abstract
Synapses are specialized junctions between neurons in brain that transmit and compute information, thereby connecting neurons into millions of overlapping and interdigitated neural circuits. Here, we posit that the establishment, properties, and dynamics of synapses are governed by a molecular logic that is controlled by diverse trans-synaptic signaling molecules. Neurexins, expressed in thousands of alternatively spliced isoforms, are central components of this dynamic code. Presynaptic neurexins regulate synapse properties via differential binding to multifarious postsynaptic ligands, such as neuroligins, cerebellin/GluD complexes, and latrophilins, thereby shaping the input/output relations of their resident neural circuits. Mutations in genes encoding neurexins and their ligands are associated with diverse neuropsychiatric disorders, especially schizophrenia, autism, and Tourette syndrome. Thus, neurexins nucleate an overall trans-synaptic signaling network that controls synapse properties, which thereby determines the precise responses of synapses to spike patterns in a neuron and circuit and which is vulnerable to impairments in neuropsychiatric disorders.
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Affiliation(s)
- Thomas C Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, CA 94305-5453, USA.
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Ehrmann I, Gazzara MR, Pagliarini V, Dalgliesh C, Kheirollahi-Chadegani M, Xu Y, Cesari E, Danilenko M, Maclennan M, Lowdon K, Vogel T, Keskivali-Bond P, Wells S, Cater H, Fort P, Santibanez-Koref M, Middei S, Sette C, Clowry GJ, Barash Y, Cunningham MO, Elliott DJ. A SLM2 Feedback Pathway Controls Cortical Network Activity and Mouse Behavior. Cell Rep 2017; 17:3269-3280. [PMID: 28009295 PMCID: PMC5199341 DOI: 10.1016/j.celrep.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/25/2016] [Accepted: 11/29/2016] [Indexed: 02/07/2023] Open
Abstract
The brain is made up of trillions of synaptic connections that together form neural networks needed for normal brain function and behavior. SLM2 is a member of a conserved family of RNA binding proteins, including Sam68 and SLM1, that control splicing of Neurexin1-3 pre-mRNAs. Whether SLM2 affects neural network activity is unknown. Here, we find that SLM2 levels are maintained by a homeostatic feedback control pathway that predates the divergence of SLM2 and Sam68. SLM2 also controls the splicing of Tomosyn2, LysoPLD/ATX, Dgkb, Kif21a, and Cask, each of which are important for synapse function. Cortical neural network activity dependent on synaptic connections between SLM2-expressing-pyramidal neurons and interneurons is decreased in Slm2-null mice. Additionally, these mice are anxious and have a decreased ability to recognize novel objects. Our data reveal a pathway of SLM2 homeostatic auto-regulation controlling brain network activity and behavior. SLM2 splicing targets are spatially controlled within the hippocampus RNA-seq reveals SLM2 feedback control and synaptic protein splicing targets Loss of SLM2 dampens patterns of hippocampal γ oscillations Loss of SLM2 changes mouse behavior that depends on these neural networks
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Affiliation(s)
- Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Matthew R Gazzara
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | | | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Eleonora Cesari
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Marie Maclennan
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Kate Lowdon
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Tanja Vogel
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Medical Faculty, University of Freiburg, 79104 Freiburg, Germany
| | | | - Sara Wells
- Mary Lyon Centre, MRC Harwell Institute, Oxfordshire OX11 ORD, UK
| | - Heather Cater
- Mary Lyon Centre, MRC Harwell Institute, Oxfordshire OX11 ORD, UK
| | - Philippe Fort
- Université Montpellier, UMR 5237, Centre de Recherche de Biologie cellulaire de Montpellier, CNRS, Montpellier 34293, France
| | | | - Silvia Middei
- Institute of Cell Biology and Neurobiology, Consiglio Nazionale delle Ricerche, Via E. Ramarini 32, 00015 Monterotondo Scalo-Roma, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome and Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Mark O Cunningham
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
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Neuroligin-induced presynaptic differentiation through SLM2-mediated splicing modifications of neurexin in cerebellar cultures. Biochem Biophys Res Commun 2017; 493:1030-1036. [PMID: 28939043 DOI: 10.1016/j.bbrc.2017.09.097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 09/18/2017] [Indexed: 11/21/2022]
Abstract
Neurexins (NRXs) and neuroligins (NLs) play important roles in synapse specification. The alternatively spliced segment 4 (AS4) of NRX genes (Nrxn) is a critical element in selective trans-synaptic interactions. However, the role of splicing of NRXs and NLs in synapse specification is not fully understood. To investigate the exact role of splice-dependent NRX-NL interaction in the specification of glutamatergic and gamma-aminobutyric acid (GABA)-ergic synapses in the cerebellum, we evaluated the synaptogenic receptor activity of NL1/2/3 isoforms in a neuron-fibroblast co-culture system, in which the Nrxn AS4 segments are manipulated using SLM2, a selective and dominant regulator of AS4 splicing. We show that ectopic SLM2 expression (SLM2 E/E) causes marked skipping of exon 20 of AS4 in cerebellar neuron culture. Whereas NLs can induce VAMP2+ presynaptic contacts from mainly glutamatergic neurons in both uninfected (control) and SLM2 E/E co-cultures, they induce VGAT+ GABAergic contacts in the control culture, but not properly in the SLM2 E/E culture. Furthermore, Nrxn3 is responsible for the NL-induced assembly of GABAergic synapses in co-culture. Importantly, lentivirus-based expression of Nrxn3 containing exon 20 restores the reduced NL-induced GABAergic contacts in the SLM2 E/E co-culture. Therefore, our findings may provide further insights into NRX-NL mediated synapse specification.
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Danilenko M, Dalgliesh C, Pagliarini V, Naro C, Ehrmann I, Feracci M, Kheirollahi-Chadegani M, Tyson-Capper A, Clowry GJ, Fort P, Dominguez C, Sette C, Elliott DJ. Binding site density enables paralog-specific activity of SLM2 and Sam68 proteins in Neurexin2 AS4 splicing control. Nucleic Acids Res 2017; 45:4120-4130. [PMID: 27994030 PMCID: PMC5397175 DOI: 10.1093/nar/gkw1277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 12/08/2016] [Indexed: 01/09/2023] Open
Abstract
SLM2 and Sam68 are splicing regulator paralogs that usually overlap in function, yet only SLM2 and not Sam68 controls the Neurexin2 AS4 exon important for brain function. Herein we find that SLM2 and Sam68 similarly bind to Neurexin2 pre-mRNA, both within the mouse cortex and in vitro. Protein domain-swap experiments identify a region including the STAR domain that differentiates SLM2 and Sam68 activity in splicing target selection, and confirm that this is not established via the variant amino acids involved in RNA contact. However, far fewer SLM2 and Sam68 RNA binding sites flank the Neurexin2 AS4 exon, compared with those flanking the Neurexin1 and Neurexin3 AS4 exons under joint control by both Sam68 and SLM2. Doubling binding site numbers switched paralog sensitivity, by placing the Neurexin2 AS4 exon under joint splicing control by both Sam68 and SLM2. Our data support a model where the density of shared RNA binding sites around a target exon, rather than different paralog-specific protein-RNA binding sites, controls functional target specificity between SLM2 and Sam68 on the Neurexin2 AS4 exon. Similar models might explain differential control by other splicing regulators within families of paralogs with indistinguishable RNA binding sites.
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Affiliation(s)
- Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Chiara Naro
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Ingrid Ehrmann
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Mikael Feracci
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | | | - Alison Tyson-Capper
- Institute for Cellular Medicine, Newcastle University, Framlington Place, Newcastle NE2 4HH, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle, UK
| | - Philippe Fort
- Université Montpellier, UMR 5237, Centre de Recherche de Biologie cellulaire de Montpellier, CNRS, 34293 Montpellier, France
| | - Cyril Dominguez
- Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 7RH, UK
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
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Abstract
Alternative pre-mRNA splicing provides an effective means for expanding coding capacity of eukaryotic genomes. Recent studies suggest that co-expression of different splice isoforms may increase diversity of RNAs and proteins at a single-cell level. A pertinent question in the field is whether such co-expression is biologically meaningful or, rather, represents insufficiently stringent splicing regulation. Here we argue that isoform co-expression may produce functional outcomes that are difficult and sometimes impossible to achieve using other regulation strategies. Far from being a ‘splicing noise’, co-expression is often established through co-ordinated activity of specific cis-elements and trans-acting factors. Further work in this area may uncover new biological functions of alternative splicing (AS) and generate important insights into mechanisms allowing different cell types to attain their unique molecular identities.
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37
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Abstract
STAR (signal transduction and activation of RNA) proteins regulate splicing of target genes that have roles in neural connectivity, survival and myelination in the vertebrate nervous system. These regulated splicing targets include mRNAs such as the Neurexins (Nrxn), SMN2 (survival of motor neuron) and MAG (myelin-associated glycoprotein). Recent work has made it possible to identify and validate STAR protein splicing targets in vivo by using genetically modified mouse models. In this review, we will discuss the importance of STAR protein splicing targets in the CNS (central nervous system).
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Harkin LF, Lindsay SJ, Xu Y, Alzu'bi A, Ferrara A, Gullon EA, James OG, Clowry GJ. Neurexins 1-3 Each Have a Distinct Pattern of Expression in the Early Developing Human Cerebral Cortex. Cereb Cortex 2017; 27:216-232. [PMID: 28013231 PMCID: PMC5654756 DOI: 10.1093/cercor/bhw394] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/16/2016] [Accepted: 12/02/2016] [Indexed: 12/17/2022] Open
Abstract
Neurexins (NRXNs) are presynaptic terminal proteins and candidate neurodevelopmental disorder susceptibility genes; mutations presumably upset synaptic stabilization and function. However, analysis of human cortical tissue samples by RNAseq and quantitative real-time PCR at 8-12 postconceptional weeks, prior to extensive synapse formation, showed expression of all three NRXNs as well as several potential binding partners. However, the levels of expression were not identical; NRXN1 increased with age and NRXN2 levels were consistently higher than for NRXN3. Immunohistochemistry for each NRXN also revealed different expression patterns at this stage of development. NRXN1 and NRXN3 immunoreactivity was generally strongest in the cortical plate and increased in the ventricular zone with age, but was weak in the synaptogenic presubplate (pSP) and marginal zone. On the other hand, NRXN2 colocalized with synaptophysin in neurites of the pSP, but especially with GAP43 and CASK in growing axons of the intermediate zone. Alternative splicing modifies the role of NRXNs and we found evidence by RNAseq for exon skipping at splice site 4 and concomitant expression of KHDBRS proteins which control this splicing. NRXN2 may play a part in early cortical synaptogenesis, but NRXNs could have diverse roles in development including axon guidance, and intercellular communication between proliferating cells and/or migrating neurons.
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Affiliation(s)
- Lauren F Harkin
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: School of Healthcare Science, Manchester Metropolitan University, Manchester, M1 5GD, UK
| | - Susan J Lindsay
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Yaobo Xu
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: Wellcome Trust, Sanger Institute, Cambridge, CB10 1SA, UK
| | - Ayman Alzu'bi
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Alexandra Ferrara
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Emily A Gullon
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
| | - Owen G James
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Parkway Drive, Newcastle upon Tyne NE1 3BZ, UK
- Present address: MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Gavin J Clowry
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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Nguyen TM, Schreiner D, Xiao L, Traunmüller L, Bornmann C, Scheiffele P. An alternative splicing switch shapes neurexin repertoires in principal neurons versus interneurons in the mouse hippocampus. eLife 2016; 5. [PMID: 27960072 PMCID: PMC5213383 DOI: 10.7554/elife.22757] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/07/2016] [Indexed: 01/18/2023] Open
Abstract
The unique anatomical and functional features of principal and interneuron populations are critical for the appropriate function of neuronal circuits. Cell type-specific properties are encoded by selective gene expression programs that shape molecular repertoires and synaptic protein complexes. However, the nature of such programs, particularly for post-transcriptional regulation at the level of alternative splicing is only beginning to emerge. We here demonstrate that transcripts encoding the synaptic adhesion molecules neurexin-1,2,3 are commonly expressed in principal cells and interneurons of the mouse hippocampus but undergo highly differential, cell type-specific alternative splicing. Principal cell-specific neurexin splice isoforms depend on the RNA-binding protein Slm2. By contrast, most parvalbumin-positive (PV+) interneurons lack Slm2, express a different neurexin splice isoform and co-express the corresponding splice isoform-specific neurexin ligand Cbln4. Conditional ablation of Nrxn alternative splice insertions selectively in PV+ cells results in elevated hippocampal network activity and impairment in a learning task. Thus, PV-cell-specific alternative splicing of neurexins is critical for neuronal circuit function DOI:http://dx.doi.org/10.7554/eLife.22757.001
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Affiliation(s)
| | | | - Le Xiao
- Biozentrum, University of Basel, Basel, Switzerland
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40
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Lara-Pezzi E, Desco M, Gatto A, Gómez-Gaviro MV. Neurogenesis: Regulation by Alternative Splicing and Related Posttranscriptional Processes. Neuroscientist 2016; 23:466-477. [PMID: 27837180 DOI: 10.1177/1073858416678604] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complexity of the mammalian brain requires highly specialized protein function and diversity. As neurons differentiate and the neuronal circuitry is established, several mRNAs undergo alternative splicing and other posttranscriptional changes that expand the variety of protein isoforms produced. Recent advances are beginning to shed light on the molecular mechanisms that regulate isoform switching during neurogenesis and the role played by specific RNA binding proteins in this process. Neurogenesis and neuronal wiring were recently shown to also be regulated by RNA degradation through nonsense-mediated decay. An additional layer of regulatory complexity in these biological processes is the interplay between alternative splicing and long noncoding RNAs. Dysregulation of posttranscriptional regulation results in defective neuronal differentiation and/or synaptic connections that lead to neurodevelopmental and psychiatric disorders.
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Affiliation(s)
- Enrique Lara-Pezzi
- 1 Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain.,2 National Heart and Lung Institute, Imperial College London, London, UK
| | - Manuel Desco
- 3 Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, Madrid, Spain.,4 Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Alberto Gatto
- 1 Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - María Victoria Gómez-Gaviro
- 3 Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III, Madrid, Spain.,4 Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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Abstract
Alternative precursor-mRNA splicing is a key mechanism for regulating gene expression in mammals and is controlled by specialized RNA-binding proteins. The misregulation of splicing is implicated in multiple neurological disorders. We describe recent mouse genetic studies of alternative splicing that reveal its critical role in both neuronal development and the function of mature neurons. We discuss the challenges in understanding the extensive genetic programmes controlled by proteins that regulate splicing, both during development and in the adult brain.
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Affiliation(s)
- Celine K Vuong
- Molecular Biology Interdepartmental Graduate Program, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Sika Zheng
- Division of Biomedical Sciences, University of California at Riverside, Riverside, California 92521, USA
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Murphy D, Cieply B, Carstens R, Ramamurthy V, Stoilov P. The Musashi 1 Controls the Splicing of Photoreceptor-Specific Exons in the Vertebrate Retina. PLoS Genet 2016; 12:e1006256. [PMID: 27541351 PMCID: PMC4991804 DOI: 10.1371/journal.pgen.1006256] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/22/2016] [Indexed: 01/08/2023] Open
Abstract
Alternative pre-mRNA splicing expands the coding capacity of eukaryotic genomes, potentially enabling a limited number of genes to govern the development of complex anatomical structures. Alternative splicing is particularly prevalent in the vertebrate nervous system, where it is required for neuronal development and function. Here, we show that photoreceptor cells, a type of sensory neuron, express a characteristic splicing program that affects a broad set of transcripts and is initiated prior to the development of the light sensing outer segments. Surprisingly, photoreceptors lack prototypical neuronal splicing factors and their splicing profile is driven to a significant degree by the Musashi 1 (MSI1) protein. A striking feature of the photoreceptor splicing program are exons that display a "switch-like" pattern of high inclusion levels in photoreceptors and near complete exclusion outside of the retina. Several ubiquitously expressed genes that are involved in the biogenesis and function of primary cilia produce highly photoreceptor specific isoforms through use of such "switch-like" exons. Our results suggest a potential role for alternative splicing in the development of photoreceptors and the conversion of their primary cilia to the light sensing outer segments.
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Affiliation(s)
- Daniel Murphy
- Department of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Benjamin Cieply
- Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Russ Carstens
- Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Visvanathan Ramamurthy
- Departments of Biochemistry, Ophthalmology and Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
| | - Peter Stoilov
- Department of Biochemistry and Cancer Institute, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia, United States of America
- * E-mail:
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43
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Traunmüller L, Gomez AM, Nguyen TM, Scheiffele P. Control of neuronal synapse specification by a highly dedicated alternative splicing program. Science 2016; 352:982-6. [PMID: 27174676 DOI: 10.1126/science.aaf2397] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/15/2016] [Indexed: 12/13/2022]
Abstract
Alternative RNA splicing represents a central mechanism for expanding the coding power of genomes. Individual RNA-binding proteins can control alternative splicing choices in hundreds of RNA transcripts, thereby tuning amounts and functions of large numbers of cellular proteins. We found that the RNA-binding protein SLM2 is essential for functional specification of glutamatergic synapses in the mouse hippocampus. Genome-wide mapping revealed a markedly selective SLM2-dependent splicing program primarily consisting of only a few target messenger RNAs that encode synaptic proteins. Genetic correction of a single SLM2-dependent target exon in the synaptic recognition molecule neurexin-1 was sufficient to rescue synaptic plasticity and behavioral defects in Slm2 knockout mice. These findings uncover a highly selective alternative splicing program that specifies synaptic properties in the central nervous system.
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Affiliation(s)
- Lisa Traunmüller
- Biozentrum, University of Basel Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Andrea M Gomez
- Biozentrum, University of Basel Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Thi-Minh Nguyen
- Biozentrum, University of Basel Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Peter Scheiffele
- Biozentrum, University of Basel Klingelbergstrasse 50-70, 4056 Basel, Switzerland
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Iijima T, Hidaka C, Iijima Y. Spatio-temporal regulations and functions of neuronal alternative RNA splicing in developing and adult brains. Neurosci Res 2016; 109:1-8. [PMID: 26853282 DOI: 10.1016/j.neures.2016.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 01/25/2016] [Accepted: 01/25/2016] [Indexed: 10/25/2022]
Abstract
Alternative pre-mRNA splicing is a fundamental mechanism that generates molecular diversity from a single gene. In the central nervous system (CNS), key neural developmental steps are thought to be controlled by alternative splicing decisions, including the molecular diversity underlying synaptic wiring, plasticity, and remodeling. Significant progress has been made in understanding the molecular mechanisms and functions of alternative pre-mRNA splicing in neurons through studies in invertebrate systems; however, recent studies have begun to uncover the potential role of neuronal alternative splicing in the mammalian CNS. This article provides an overview of recent findings regarding the regulation and function of neuronal alternative splicing. In particular, we focus on the spatio-temporal regulation of neurexin, a synaptic adhesion molecule, by neuronal cell type-specific factors and neuronal activity, which are thought to be especially important for characterizing neural development and function within the mammalian CNS. Notably, there is increasing evidence that implicates the dysregulation of neuronal splicing events in several neurological disorders. Therefore, understanding the detailed mechanisms of neuronal alternative splicing in the mammalian CNS may provide plausible treatment strategies for these diseases.
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Affiliation(s)
- Takatoshi Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Tokai University Institute of Innovative Science and Technology, 4-1-1 Kitakaname, Hiratsuka City, Kanagawa 259-1292, Japan; School of Medicine, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan.
| | - Chiharu Hidaka
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Tokai University Institute of Innovative Science and Technology, 4-1-1 Kitakaname, Hiratsuka City, Kanagawa 259-1292, Japan; School of Medicine, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
| | - Yoko Iijima
- Tokai University Institute of Innovative Science and Technology, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan; Tokai University Institute of Innovative Science and Technology, 4-1-1 Kitakaname, Hiratsuka City, Kanagawa 259-1292, Japan; School of Medicine, Tokai University, 143 Shimokasuya, Isehara City, Kanagawa 259-1193, Japan
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45
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Abstract
UNLABELLED Synapses depend on trafficking of key membrane proteins by lateral diffusion from surface populations and by exocytosis from intracellular pools. The cell adhesion molecule neurexin (Nrxn) plays essential roles in synapses, but the dynamics and regulation of its trafficking are unknown. Here, we performed single-particle tracking and live imaging of transfected, epitope-tagged Nrxn variants in cultured rat and mouse wild-type or knock-out neurons. We observed that structurally larger αNrxn molecules are more mobile in the plasma membrane than smaller βNrxns because αNrxns displayed higher diffusion coefficients in extrasynaptic regions and excitatory or inhibitory terminals. We found that well characterized interactions with extracellular binding partners regulate the surface mobility of Nrxns. Binding to neurexophilin-1 (Nxph1) reduced the surface diffusion of αNrxns when both molecules were coexpressed. Conversely, impeding other interactions by insertion of splice sequence #4 or removal of extracellular Ca(2+) augmented the mobility of αNrxns and βNrxns. We also determined that fast axonal transport delivers Nrxns to the neuronal surface because Nrxns comigrate as cargo on synaptic vesicle protein transport vesicles (STVs). Unlike surface mobility, intracellular transport of βNrxn(+) STVs was faster than that of αNrxns, but both depended on the microtubule motor protein KIF1A and neuronal activity regulated the velocity. Large spontaneous fusion of Nrxn(+) STVs occurred simultaneously with synaptophysin on axonal membranes mostly outside of active presynaptic terminals. Surface Nrxns enriched at synaptic terminals where αNrxns and Nxph1/αNrxns recruited GABAAR subunits. Therefore, our results identify regulated dynamic trafficking as an important property of Nrxns that corroborates their function at synapses. SIGNIFICANCE STATEMENT Synapses mediate most functions in our brains and depend on the precise and timely delivery of key molecules throughout life. Neurexins (Nrxns) are essential synaptic cell adhesion molecules that are involved in synaptic transmission and differentiation of synaptic contacts. In addition, Nrxns have been linked to neuropsychiatric diseases such as autism. Because little is known about the dynamic aspects of trafficking of neurexins to synapses, we investigated this important question using single-molecule tracking and time-lapse imaging. We identify distinct differences between major Nrxn variants both in surface mobility and during intracellular transport. Because their dynamic behavior is highly regulated, for example, by different binding activities, these processes have immediate consequences for the function of Nrxns at synapses.
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Feracci M, Foot JN, Grellscheid SN, Danilenko M, Stehle R, Gonchar O, Kang HS, Dalgliesh C, Meyer NH, Liu Y, Lahat A, Sattler M, Eperon IC, Elliott DJ, Dominguez C. Structural basis of RNA recognition and dimerization by the STAR proteins T-STAR and Sam68. Nat Commun 2016; 7:10355. [PMID: 26758068 PMCID: PMC4735526 DOI: 10.1038/ncomms10355] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 12/01/2015] [Indexed: 11/13/2022] Open
Abstract
Sam68 and T-STAR are members of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins. T-STAR is a tissue-specific paralogue that regulates the alternative splicing of neuronal pre-mRNAs. STAR proteins differ from most splicing factors, in that they contain a single RNA-binding domain. Their specificity of RNA recognition is thought to arise from their property to homodimerize, but how dimerization influences their function remains unknown. Here, we establish at atomic resolution how T-STAR and Sam68 bind to RNA, revealing an unexpected mode of dimerization different from other members of the STAR family. We further demonstrate that this unique dimerization interface is crucial for their biological activity in splicing regulation, and suggest that the increased RNA affinity through dimer formation is a crucial parameter enabling these proteins to select their functional targets within the transcriptome. Sam68 and T-STAR are members of the STAR family of proteins, which regulate various aspects of RNA metabolism. Here, the authors reveal structural features required for alternative splicing regulation by these proteins.
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Affiliation(s)
- Mikael Feracci
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Jaelle N Foot
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Sushma N Grellscheid
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Marina Danilenko
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Ralf Stehle
- Center for Integrated Protein Science Munich at Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstr. 4, DE-85747 Garching, Germany
| | - Oksana Gonchar
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Hyun-Seo Kang
- Center for Integrated Protein Science Munich at Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstr. 4, DE-85747 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, DE-85764 Oberschleißheim, Germany
| | - Caroline Dalgliesh
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - N Helge Meyer
- Center for Integrated Protein Science Munich at Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstr. 4, DE-85747 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, DE-85764 Oberschleißheim, Germany
| | - Yilei Liu
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Albert Lahat
- School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, UK
| | - Michael Sattler
- Center for Integrated Protein Science Munich at Biomolecular NMR Spectroscopy, Department Chemie, Technische Universität München, Lichtenbergstr. 4, DE-85747 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, DE-85764 Oberschleißheim, Germany
| | - Ian C Eperon
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
| | - David J Elliott
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle NE1 3BZ, UK
| | - Cyril Dominguez
- Department of Molecular and Cell Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 9HN, UK
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47
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Licatalosi DD. Roles of RNA-binding Proteins and Post-transcriptional Regulation in Driving Male Germ Cell Development in the Mouse. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:123-51. [PMID: 27256385 DOI: 10.1007/978-3-319-29073-7_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tissue development and homeostasis are dependent on highly regulated gene expression programs in which cell-specific combinations of regulatory factors determine which genes are expressed and the post-transcriptional fate of the resulting RNA transcripts. Post-transcriptional regulation of gene expression by RNA-binding proteins has critical roles in tissue development-allowing individual genes to generate multiple RNA and protein products, and the timing, location, and abundance of protein synthesis to be finely controlled. Extensive post-transcriptional regulation occurs during mammalian gametogenesis, including high levels of alternative mRNA expression, stage-specific expression of mRNA variants, broad translational repression, and stage-specific activation of mRNA translation. In this chapter, an overview of the roles of RNA-binding proteins and the importance of post-transcriptional regulation in male germ cell development in the mouse is presented.
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Affiliation(s)
- Donny D Licatalosi
- Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH, 44106, USA.
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48
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Pagliarini V, Pelosi L, Bustamante MB, Nobili A, Berardinelli MG, D'Amelio M, Musarò A, Sette C. SAM68 is a physiological regulator of SMN2 splicing in spinal muscular atrophy. J Cell Biol 2015; 211:77-90. [PMID: 26438828 PMCID: PMC4602033 DOI: 10.1083/jcb.201502059] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 08/31/2015] [Indexed: 02/05/2023] Open
Abstract
Knockout of the splicing factor SAM68 promotes SMN2 splicing, improving neuromuscular defects and viability in SMA mice. Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of motor neurons in patients with null mutations in the SMN1 gene. The almost identical SMN2 gene is unable to compensate for this deficiency because of the skipping of exon 7 during pre–messenger RNA (mRNA) processing. Although several splicing factors can modulate SMN2 splicing in vitro, the physiological regulators of this disease-causing event are unknown. We found that knockout of the splicing factor SAM68 partially rescued body weight and viability of SMAΔ7 mice. Ablation of SAM68 function promoted SMN2 splicing and expression in SMAΔ7 mice, correlating with amelioration of SMA-related defects in motor neurons and skeletal muscles. Mechanistically, SAM68 binds to SMN2 pre-mRNA, favoring recruitment of the splicing repressor hnRNP A1 and interfering with that of U2AF65 at the 3′ splice site of exon 7. These findings identify SAM68 as the first physiological regulator of SMN2 splicing in an SMA mouse model.
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Affiliation(s)
- Vittoria Pagliarini
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Laura Pelosi
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy
| | - Maria Blaire Bustamante
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
| | - Annalisa Nobili
- Laboratory of Molecular Neuroscience, Fondazione Santa Lucia, 00143 Rome, Italy Medical School University Campus Bio-Medico, 00128 Rome, Italy
| | - Maria Grazia Berardinelli
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy
| | - Marcello D'Amelio
- Laboratory of Molecular Neuroscience, Fondazione Santa Lucia, 00143 Rome, Italy Medical School University Campus Bio-Medico, 00128 Rome, Italy
| | - Antonio Musarò
- Institute Pasteur Cenci-Bolognetti Foundation, DAHFMO-Unit of Histology and Medical Embryology, IIM, University of Rome La Sapienza, 00161 Rome, Italy Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy Laboratory of Neuroembryology, Fondazione Santa Lucia, 00143 Rome, Italy
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49
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Crisci A, Raleff F, Bagdiul I, Raabe M, Urlaub H, Rain JC, Krämer A. Mammalian splicing factor SF1 interacts with SURP domains of U2 snRNP-associated proteins. Nucleic Acids Res 2015; 43:10456-73. [PMID: 26420826 PMCID: PMC4666396 DOI: 10.1093/nar/gkv952] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 09/10/2015] [Indexed: 02/03/2023] Open
Abstract
Splicing factor 1 (SF1) recognizes the branch point sequence (BPS) at the 3′ splice site during the formation of early complex E, thereby pre-bulging the BPS adenosine, thought to facilitate subsequent base-pairing of the U2 snRNA with the BPS. The 65-kDa subunit of U2 snRNP auxiliary factor (U2AF65) interacts with SF1 and was shown to recruit the U2 snRNP to the spliceosome. Co-immunoprecipitation experiments of SF1-interacting proteins from HeLa cell extracts shown here are consistent with the presence of SF1 in early splicing complexes. Surprisingly almost all U2 snRNP proteins were found associated with SF1. Yeast two-hybrid screens identified two SURP domain-containing U2 snRNP proteins as partners of SF1. A short, evolutionarily conserved region of SF1 interacts with the SURP domains, stressing their role in protein–protein interactions. A reduction of A complex formation in SF1-depleted extracts could be rescued with recombinant SF1 containing the SURP-interaction domain, but only partial rescue was observed with SF1 lacking this sequence. Thus, SF1 can initially recruit the U2 snRNP to the spliceosome during E complex formation, whereas U2AF65 may stabilize the association of the U2 snRNP with the spliceosome at later times. In addition, these findings may have implications for alternative splicing decisions.
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Affiliation(s)
- Angela Crisci
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Flore Raleff
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Ivona Bagdiul
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Monika Raabe
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, D-37075 Göttingen, Germany
| | | | - Angela Krämer
- Department of Cell Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland
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50
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Fuccillo MV, Földy C, Gökce Ö, Rothwell PE, Sun GL, Malenka RC, Südhof TC. Single-Cell mRNA Profiling Reveals Cell-Type-Specific Expression of Neurexin Isoforms. Neuron 2015; 87:326-40. [PMID: 26182417 DOI: 10.1016/j.neuron.2015.06.028] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 06/10/2015] [Accepted: 06/17/2015] [Indexed: 12/23/2022]
Abstract
Neurexins are considered central organizers of synapse architecture that are implicated in neuropsychiatric disorders. Expression of neurexins in hundreds of alternatively spliced isoforms suggested that individual neurons might exhibit a cell-type-specific neurexin expression pattern (a neurexin code). To test this hypothesis, we quantified the single-cell levels of neurexin isoforms and other trans-synaptic cell-adhesion molecules by microfluidics-based RT-PCR. We show that the neurexin repertoire displays pronounced cell-type specificity that is remarkably consistent within each type of neuron. Furthermore, we uncovered region-specific regulation of neurexin transcription and splice-site usage. Finally, we demonstrate that the transcriptional profiles of neurexins can be altered in an experience-dependent fashion by exposure to a drug of abuse. Our data provide evidence of cell-type-specific expression patterns of multiple neurexins at the single-cell level and suggest that expression of synaptic cell-adhesion molecules overlaps with other key features of cellular identity and diversity.
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Affiliation(s)
- Marc V Fuccillo
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA; Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA.
| | - Csaba Földy
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA; Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Özgün Gökce
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Patrick E Rothwell
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA; Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Gordon L Sun
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Robert C Malenka
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, School of Medicine, Stanford University, Stanford, CA 94305, USA.
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