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Guma E, Bordignon PDC, Devenyi GA, Gallino D, Anastassiadis C, Cvetkovska V, Barry AD, Snook E, Germann J, Greenwood CMT, Misic B, Bagot RC, Chakravarty MM. Early or Late Gestational Exposure to Maternal Immune Activation Alters Neurodevelopmental Trajectories in Mice: An Integrated Neuroimaging, Behavioral, and Transcriptional Study. Biol Psychiatry 2021; 90:328-341. [PMID: 34053674 DOI: 10.1016/j.biopsych.2021.03.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/23/2021] [Accepted: 03/15/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Exposure to maternal immune activation (MIA) in utero is a risk factor for neurodevelopmental disorders later in life. The impact of the gestational timing of MIA exposure on downstream development remains unclear. METHODS We characterized neurodevelopmental trajectories of mice exposed to the viral mimetic poly I:C (polyinosinic:polycytidylic acid) either on gestational day 9 (early) or on day 17 (late) using longitudinal structural magnetic resonance imaging from weaning to adulthood. Using multivariate methods, we related neuroimaging and behavioral variables for the time of greatest alteration (adolescence/early adulthood) and identified regions for further investigation using RNA sequencing. RESULTS Early MIA exposure was associated with accelerated brain volume increases in adolescence/early adulthood that normalized in later adulthood in the striatum, hippocampus, and cingulate cortex. Similarly, alterations in anxiety-like, stereotypic, and sensorimotor gating behaviors observed in adolescence normalized in adulthood. MIA exposure in late gestation had less impact on anatomical and behavioral profiles. Multivariate maps associated anxiety-like, social, and sensorimotor gating deficits with volume of the dorsal and ventral hippocampus and anterior cingulate cortex, among others. The most transcriptional changes were observed in the dorsal hippocampus, with genes enriched for fibroblast growth factor regulation, autistic behaviors, inflammatory pathways, and microRNA regulation. CONCLUSIONS Leveraging an integrated hypothesis- and data-driven approach linking brain-behavior alterations to the transcriptome, we found that MIA timing differentially affects offspring development. Exposure in late gestation leads to subthreshold deficits, whereas exposure in early gestation perturbs brain development mechanisms implicated in neurodevelopmental disorders.
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Affiliation(s)
- Elisa Guma
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada.
| | - Pedro do Couto Bordignon
- Department of Psychology, McGill University, Montreal, Quebec, Canada; Ludmer Center for Neuroinformatics and Mental Health, Montreal, Quebec, Canada
| | - Gabriel A Devenyi
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Daniel Gallino
- Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Chloe Anastassiadis
- Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Institute of Medical Science & Collaborative Program in Neuroscience, University of Toronto, Toronto, Ontario, Canada
| | | | - Amadou D Barry
- Departments of Human Genetics and Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; Ludmer Center for Neuroinformatics and Mental Health, Montreal, Quebec, Canada
| | - Emily Snook
- Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Jurgen Germann
- Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada; University Health Network, Toronto, Ontario, Canada
| | - Celia M T Greenwood
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada; Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montreal, Quebec, Canada; Departments of Human Genetics and Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada; Ludmer Center for Neuroinformatics and Mental Health, Montreal, Quebec, Canada
| | - Bratislav Misic
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Rosemary C Bagot
- Department of Psychology, McGill University, Montreal, Quebec, Canada; Ludmer Center for Neuroinformatics and Mental Health, Montreal, Quebec, Canada
| | - M Mallar Chakravarty
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada; Department of Psychiatry, McGill University, Montreal, Quebec, Canada; Department of Biological and Biomedical Engineering, McGill University, Montreal, Quebec, Canada; Computational Brain Imaging Lab, Cerebral Imaging Center, Douglas Mental Health University Institute, Montreal, Quebec, Canada.
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Cvetkovska V, Bagot RC. Ophn1 regulation of prefrontal inhibition: A mechanism for stress susceptibility in intellectual disability. Neuron 2021; 109:1583-1584. [PMID: 34015262 DOI: 10.1016/j.neuron.2021.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Wang et al. (2021) characterize the molecular, cellular, and circuit-level role of Oligophrenin-1 in prefrontal parvalbumin interneurons, demonstrating that loss of Ophn1 function in these neurons is a mechanism for increased susceptibility to stress in intellectual disability caused by OPHN1 mutations.
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Affiliation(s)
| | - Rosemary C Bagot
- Department of Psychology, McGill University, Montréal, QC, Canada; Ludmer Centre for Neuroinformatics and Mental Health, Montréal, QC, Canada.
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3
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Elegheert J, Cvetkovska V, Clayton AJ, Heroven C, Vennekens KM, Smukowski SN, Regan MC, Jia W, Smith AC, Furukawa H, Savas JN, de Wit J, Begbie J, Craig AM, Aricescu AR. Structural Mechanism for Modulation of Synaptic Neuroligin-Neurexin Signaling by MDGA Proteins. Neuron 2021; 109:189-190. [PMID: 33412094 PMCID: PMC7837113 DOI: 10.1016/j.neuron.2020.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Muir J, Tse YC, Iyer ES, Biris J, Cvetkovska V, Lopez J, Bagot RC. Ventral Hippocampal Afferents to Nucleus Accumbens Encode Both Latent Vulnerability and Stress-Induced Susceptibility. Biol Psychiatry 2020; 88:843-854. [PMID: 32682566 DOI: 10.1016/j.biopsych.2020.05.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/25/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Stress is a major risk factor for depression, but not everyone responds to stress in the same way. Identifying why certain individuals are more susceptible is essential for targeted treatment and prevention. In rodents, nucleus accumbens (NAc) afferents from the ventral hippocampus (vHIP) are implicated in stress-induced susceptibility, but little is known about how this pathway might encode future vulnerability or specific behavioral phenotypes. METHODS We used fiber photometry to record in vivo activity in vHIP-NAc afferents during tests of depressive- and anxiety-like behavior in male and female mice, both before and after a sex-specific chronic variable stress protocol, to probe relationships between prestress neural activity and behavior and potential predictors of poststress behavioral adaptation. Furthermore, we examined chronic variable stress-induced alterations in vHIP-NAc activity in vivo and used ex vivo slice electrophysiology to identify the mechanism of this change. RESULTS We identified behavioral specificity of the vHIP-NAc pathway to anxiety-like and social interaction behavior. We also showed that this activity is broadly predictive of stress-induced susceptibility in both sexes, while prestress behavior is predictive only of anxiety-like behavior. We observed a stress-induced increase in in vivo vHIP-NAc activity coincident with an increase in spontaneous excitatory postsynaptic current frequency. CONCLUSIONS We implicate vHIP-NAc in social interaction and anxiety-like behavior and identify markers of vulnerability in this neural signal, with elevated prestress vHIP-NAc activity predicting increased susceptibility across behavioral domains. Our findings indicate that individual differences in neural activity and behavior play a role in predetermining susceptibility to later stress, providing insight into mechanisms of vulnerability.
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Affiliation(s)
- Jessie Muir
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Yiu Chung Tse
- Department of Psychology, McGill University, Montréal, Quebec, Canada
| | - Eshaan S Iyer
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Julia Biris
- Department of Psychology, McGill University, Montréal, Quebec, Canada
| | | | - Joëlle Lopez
- Department of Psychology, McGill University, Montréal, Quebec, Canada
| | - Rosemary C Bagot
- Department of Psychology, McGill University, Montréal, Quebec, Canada; Ludmer Centre for Neuroinformatics and Mental Health, Montréal, Quebec, Canada.
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Connor SA, Ammendrup-Johnsen I, Kishimoto Y, Karimi Tari P, Cvetkovska V, Harada T, Ojima D, Yamamoto T, Wang YT, Craig AM. Loss of Synapse Repressor MDGA1 Enhances Perisomatic Inhibition, Confers Resistance to Network Excitation, and Impairs Cognitive Function. Cell Rep 2019; 21:3637-3645. [PMID: 29281813 DOI: 10.1016/j.celrep.2017.11.109] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 10/10/2017] [Accepted: 11/29/2017] [Indexed: 01/27/2023] Open
Abstract
Synaptopathies contributing to neurodevelopmental disorders are linked to mutations in synaptic organizing molecules, including postsynaptic neuroligins, presynaptic neurexins, and MDGAs, which regulate their interaction. The role of MDGA1 in suppressing inhibitory versus excitatory synapses is controversial based on in vitro studies. We show that genetic deletion of MDGA1 in vivo elevates hippocampal CA1 inhibitory, but not excitatory, synapse density and transmission. Furthermore, MDGA1 is selectively expressed by pyramidal neurons and regulates perisomatic, but not distal dendritic, inhibitory synapses. Mdga1-/- hippocampal networks demonstrate muted responses to neural excitation, and Mdga1-/- mice are resistant to induced seizures. Mdga1-/- mice further demonstrate compromised hippocampal long-term potentiation, consistent with observed deficits in spatial and context-dependent learning and memory. These results suggest that mutations in MDGA1 may contribute to cognitive deficits through altered synaptic transmission and plasticity by loss of suppression of inhibitory synapse development in a subcellular domain- and cell-type-selective manner.
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Affiliation(s)
- Steven A Connor
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada; Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ina Ammendrup-Johnsen
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yasushi Kishimoto
- Department of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2101, Japan
| | - Parisa Karimi Tari
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Vedrana Cvetkovska
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Takashi Harada
- Department of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2101, Japan
| | - Daiki Ojima
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa 761-0793, Japan
| | - Tohru Yamamoto
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Miki-cho, Kagawa 761-0793, Japan
| | - Yu Tian Wang
- Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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Elegheert J, Cvetkovska V, Clayton AJ, Heroven C, Vennekens KM, Smukowski SN, Regan MC, Jia W, Smith AC, Furukawa H, Savas JN, de Wit J, Begbie J, Craig AM, Aricescu AR. Structural Mechanism for Modulation of Synaptic Neuroligin-Neurexin Signaling by MDGA Proteins. Neuron 2017; 96:242-244. [PMID: 28957672 PMCID: PMC5625881 DOI: 10.1016/j.neuron.2017.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Elegheert J, Cvetkovska V, Clayton AJ, Heroven C, Vennekens KM, Smukowski SN, Regan MC, Jia W, Smith AC, Furukawa H, Savas JN, de Wit J, Begbie J, Craig AM, Aricescu AR. Structural Mechanism for Modulation of Synaptic Neuroligin-Neurexin Signaling by MDGA Proteins. Neuron 2017; 95:896-913.e10. [PMID: 28817804 PMCID: PMC5563082 DOI: 10.1016/j.neuron.2017.07.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 06/22/2017] [Accepted: 07/28/2017] [Indexed: 01/30/2023]
Abstract
Neuroligin-neurexin (NL-NRX) complexes are fundamental synaptic organizers in the central nervous system. An accurate spatial and temporal control of NL-NRX signaling is crucial to balance excitatory and inhibitory neurotransmission, and perturbations are linked with neurodevelopmental and psychiatric disorders. MDGA proteins bind NLs and control their function and interaction with NRXs via unknown mechanisms. Here, we report crystal structures of MDGA1, the NL1-MDGA1 complex, and a spliced NL1 isoform. Two large, multi-domain MDGA molecules fold into rigid triangular structures, cradling a dimeric NL to prevent NRX binding. Structural analyses guided the discovery of a broad, splicing-modulated interaction network between MDGA and NL family members and helped rationalize the impact of autism-linked mutations. We demonstrate that expression levels largely determine whether MDGAs act selectively or suppress the synapse organizing function of multiple NLs. These results illustrate a potentially brain-wide regulatory mechanism for NL-NRX signaling modulation. The MDGA1 extracellular region has an unusual triangular multi-domain arrangement The NL1-MDGA1 complex structure reveals how MDGA proteins block neurexin binding MDGA1 and MDGA2 bind all NL isoforms, a process fine-tuned by alternative splicing MDGA1 and MDGA2 suppress NL synaptogenic activity in a concentration-dependent manner
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Affiliation(s)
- Jonathan Elegheert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
| | - Vedrana Cvetkovska
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Amber J Clayton
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Christina Heroven
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Kristel M Vennekens
- VIB Center for Brain and Disease Research, Herestraat 49, B-3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Samuel N Smukowski
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Michael C Regan
- Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Wanyi Jia
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Alexandra C Smith
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Hiro Furukawa
- Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA
| | - Jeffrey N Savas
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Joris de Wit
- VIB Center for Brain and Disease Research, Herestraat 49, B-3000 Leuven, Belgium; Department of Neurosciences, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Jo Begbie
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.
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Lo CA, Kays I, Emran F, Lin TJ, Cvetkovska V, Chen BE. Quantification of Protein Levels in Single Living Cells. Cell Rep 2015; 13:2634-2644. [PMID: 26686644 DOI: 10.1016/j.celrep.2015.11.048] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 09/16/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022] Open
Abstract
Accurate measurement of the amount of specific protein a cell produces is important for investigating basic molecular processes. We have developed a technique that allows for quantitation of protein levels in single cells in vivo. This protein quantitation ratioing (PQR) technique uses a genetic tag that produces a stoichiometric ratio of a fluorescent protein reporter and the protein of interest during protein translation. The fluorescence intensity is proportional to the number of molecules produced of the protein of interest and is used to determine the relative amount of protein within the cell. We use PQR to quantify protein expression of different genes using quantitative imaging, electrophysiology, and phenotype. We use genome editing to insert Protein Quantitation Reporters into endogenous genomic loci in three different genomes for quantitation of endogenous protein levels. The PQR technique will allow for a wide range of quantitative experiments examining gene-to-phenotype relationships with greater accuracy.
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Affiliation(s)
- Chiu-An Lo
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada
| | - Ibrahim Kays
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada
| | - Farida Emran
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada
| | - Tsung-Jung Lin
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada
| | - Vedrana Cvetkovska
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada
| | - Brian Edwin Chen
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, QC H3G 1A4, Canada; Departments of Medicine and Neurology and Neurosurgery, McGill University, Montréal, QC H3G 1A4, Canada.
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Kays I, Cvetkovska V, Chen BE. Structural and functional analysis of single neurons to correlate synaptic connectivity with grooming behavior. Nat Protoc 2013; 9:1-10. [PMID: 24309972 DOI: 10.1038/nprot.2013.157] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We describe a protocol to image the complex axonal branching structure of identified mechanosensory neurons in Drosophila, combined with a behavioral assay to evaluate the functional output of the neuron. The stimulation of identified mechanosensory neurons in live animals produces a stereotyped grooming reflex. The mechanosensory axonal arbor within the CNS is subsequently labeled with a lipophilic fluorescent dye and imaged by fluorescence microscopy. The behavioral output can therefore be correlated to the axonal morphology of the stimulated neuron in the same animal. Combining this protocol with genetic analysis provides a powerful tool for identifying the roles of molecules involved in different aspects of hard-wired neural circuit formation underlying an innate behavior. From behavioral analysis to axonal imaging, the protocol takes 4 d.
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Affiliation(s)
- Ibrahim Kays
- 1] Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada. [2]
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Cvetkovska V, Hibbert AD, Emran F, Chen BE. Overexpression of Down syndrome cell adhesion molecule impairs precise synaptic targeting. Nat Neurosci 2013; 16:677-82. [PMID: 23666178 PMCID: PMC3954815 DOI: 10.1038/nn.3396] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 04/10/2013] [Indexed: 12/17/2022]
Abstract
Fragile X syndrome is caused by loss of Fragile X Mental Retardation Protein (FMRP), an RNA binding protein that suppresses protein translation. Here, we identified Down Syndrome Cell Adhesion Molecule (Dscam) RNA, a molecule involved in neural development and implicated in Down syndrome, bound to FMRP. Elevated Dscam protein levels in Drosophila FMRP null animals and in animals with three copies of the Dscam gene both produced specific and similar synaptic targeting errors in a hard-wired neural circuit which impaired the animal’s sensory perception. Reducing Dscam levels in FMRP null animals reduced synaptic targeting errors and rescued behavioral responses. Our results demonstrate that excess Dscam protein may be a common molecular mechanism underlying altered neural wiring in major causes of intellectual disability.
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Affiliation(s)
- Vedrana Cvetkovska
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
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