1
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Yoshikawa S, Tang P, Simpson JH. Mechanosensory and command contributions to the Drosophila grooming sequence. Curr Biol 2024; 34:2066-2076.e3. [PMID: 38657610 DOI: 10.1016/j.cub.2024.04.003] [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: 11/13/2023] [Revised: 02/14/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024]
Abstract
Flies groom in response to competing mechanosensory cues in an anterior-to-posterior order using specific legs. From behavior screens, we identified a pair of cholinergic command-like neurons, Mago-no-Te (MGT), whose optogenetic activation elicits thoracic grooming by the back legs. Thoracic grooming is typically composed of body sweeps and leg rubs in alternation, but clonal analysis coupled with amputation experiments revealed that MGT activation only commands the body sweeps: initiation of leg rubbing requires contact between the leg and thorax. With new electron microscopy (EM) connectome data for the ventral nerve cord (VNC), we uncovered a circuit-based explanation for why stimulation of posterior thoracic mechanosensory bristles initiates cleaning by the back legs. Our previous work showed that flies weigh mechanosensory inputs across the body to select which part to groom, but we did not know why the thorax was always cleaned last. Here, the connectome for the VNC enabled us to identify a pair of GABAergic inhibitory neurons, UMGT1, that receives diverse sensory inputs and synapses onto both MGT and components of its downstream circuits. Optogenetic activation of UMGT1 suppresses thoracic cleaning, representing a mechanism by which mechanosensory stimuli on other body parts could take precedence in the grooming hierarchy. We also anatomically mapped the pre-motor circuit downstream of MGT, including inhibitory feedback connections that may enable rhythmicity and coordination of limb movement during thoracic grooming. The combination of behavioral screens and connectome analysis allowed us to identify a neural circuit connecting sensory-to-motor neurons that contributes to thoracic grooming.
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Affiliation(s)
- Shingo Yoshikawa
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Paul Tang
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Julie H Simpson
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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2
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Kuhn BN, Cannella N, Sanches T, Peng B, Chitre A, Polesskaya O, Gupta A, Woods LCS, Chung D, Ciccocioppo R, Kalivas PW, Palmer AA. Genome-wide association study reveals multiple loci for analgesia and opioid consumption behaviors associated with heroin vulnerability in outbred rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.27.582340. [PMID: 38712202 PMCID: PMC11071306 DOI: 10.1101/2024.02.27.582340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The increased prevalence of opioid use disorder (OUD) has made it imperative to disentangle the biological mechanisms contributing to individual differences in susceptibility to OUD. OUD shows strong heritability, however genetic variants contributing toward vulnerability remain poorly defined. We performed a genome-wide association study (GWAS) using over 850 male and female heterogeneous stock rats to identify genes underlying behaviors associated with OUD such as analgesia, as well as heroin-taking, refraining and seeking behaviors. By using an animal model of OUD, we were able to identify genetic variants associated with distinct OUD behaviors while maintaining a uniform environment, an experimental design not easily achieved in humans. Furthermore, we applied an animal model capturing individual variation in OUD propensity to assess if GWAS results were associated with OUD vulnerable versus resilient behavioral phenotypes. Our findings confirm the heritability of several OUD-like behaviors, including overall phenotype. We identified several genetic variants associated with basal analgesia prior to heroin experience, heroin consumption, escalation of intake, and motivation to obtain heroin. Ets2 , a regulator of microglia functional plasticity, and its eQTL PCP4 were identified for heroin consumption, and were associated with an OUD vulnerable phenotype through phenotype wide association study analysis. Furthermore, the coding variant Phd1l2 and the eQTL MMP15 for break point are both known mediators of addiction-related behaviors, and correlated with OUD vulnerability. These findings identify novel genetic markers related to individual differences in the susceptibility to OUD-relevant behaviors.
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3
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Eichler K, Hampel S, Alejandro-García A, Calle-Schuler SA, Santana-Cruz A, Kmecova L, Blagburn JM, Hoopfer ED, Seeds AM. Somatotopic organization among parallel sensory pathways that promote a grooming sequence in Drosophila. eLife 2024; 12:RP87602. [PMID: 38634460 PMCID: PMC11026096 DOI: 10.7554/elife.87602] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2024] Open
Abstract
Mechanosensory neurons located across the body surface respond to tactile stimuli and elicit diverse behavioral responses, from relatively simple stimulus location-aimed movements to complex movement sequences. How mechanosensory neurons and their postsynaptic circuits influence such diverse behaviors remains unclear. We previously discovered that Drosophila perform a body location-prioritized grooming sequence when mechanosensory neurons at different locations on the head and body are simultaneously stimulated by dust (Hampel et al., 2017; Seeds et al., 2014). Here, we identify nearly all mechanosensory neurons on the Drosophila head that individually elicit aimed grooming of specific head locations, while collectively eliciting a whole head grooming sequence. Different tracing methods were used to reconstruct the projections of these neurons from different locations on the head to their distinct arborizations in the brain. This provides the first synaptic resolution somatotopic map of a head, and defines the parallel-projecting mechanosensory pathways that elicit head grooming.
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Affiliation(s)
- Katharina Eichler
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Stefanie Hampel
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Adrián Alejandro-García
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Steven A Calle-Schuler
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Alexis Santana-Cruz
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Lucia Kmecova
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Jonathan M Blagburn
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
| | - Eric D Hoopfer
- Neuroscience Program, Carleton CollegeNorthfieldUnited States
| | - Andrew M Seeds
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences CampusSan JuanPuerto Rico
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4
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Sukreet S, Rafii MS, Rissman RA. From understanding to action: Exploring molecular connections of Down syndrome to Alzheimer's disease for targeted therapeutic approach. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2024; 16:e12580. [PMID: 38623383 PMCID: PMC11016820 DOI: 10.1002/dad2.12580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 04/17/2024]
Abstract
Down syndrome (DS) is caused by a third copy of chromosome 21. Alzheimer's disease (AD) is a neurodegenerative condition characterized by the deposition of amyloid-beta (Aβ) plaques and neurofibrillary tangles in the brain. Both disorders have elevated Aβ, tau, dysregulated immune response, and inflammation. In people with DS, Hsa21 genes like APP and DYRK1A are overexpressed, causing an accumulation of amyloid and neurofibrillary tangles, and potentially contributing to an increased risk of AD. As a result, people with DS are a key demographic for research into AD therapeutics and prevention. The molecular links between DS and AD shed insights into the underlying causes of both diseases and highlight potential therapeutic targets. Also, using biomarkers for early diagnosis and treatment monitoring is an active area of research, and genetic screening for high-risk individuals may enable earlier intervention. Finally, the fundamental mechanistic parallels between DS and AD emphasize the necessity for continued research into effective treatments and prevention measures for DS patients at risk for AD. Genetic screening with customized therapy approaches may help the DS population in current clinical studies and future biomarkers.
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Affiliation(s)
- Sonal Sukreet
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
| | - Michael S. Rafii
- Department of Neurology, Alzheimer's Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
| | - Robert A. Rissman
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
- Department Physiology and Neuroscience, Alzheimer’s Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
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5
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Dewa KI, Arimura N, Kakegawa W, Itoh M, Adachi T, Miyashita S, Inoue YU, Hizawa K, Hori K, Honjoya N, Yagishita H, Taya S, Miyazaki T, Usui C, Tatsumoto S, Tsuzuki A, Uetake H, Sakai K, Yamakawa K, Sasaki T, Nagai J, Kawaguchi Y, Sone M, Inoue T, Go Y, Ichinohe N, Kaibuchi K, Watanabe M, Koizumi S, Yuzaki M, Hoshino M. Neuronal DSCAM regulates the peri-synaptic localization of GLAST in Bergmann glia for functional synapse formation. Nat Commun 2024; 15:458. [PMID: 38302444 PMCID: PMC10834496 DOI: 10.1038/s41467-023-44579-z] [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: 03/15/2022] [Accepted: 12/19/2023] [Indexed: 02/03/2024] Open
Abstract
In the central nervous system, astrocytes enable appropriate synapse function through glutamate clearance from the synaptic cleft; however, it remains unclear how astrocytic glutamate transporters function at peri-synaptic contact. Here, we report that Down syndrome cell adhesion molecule (DSCAM) in Purkinje cells controls synapse formation and function in the developing cerebellum. Dscam-mutant mice show defects in CF synapse translocation as is observed in loss of function mutations in the astrocytic glutamate transporter GLAST expressed in Bergmann glia. These mice show impaired glutamate clearance and the delocalization of GLAST away from the cleft of parallel fibre (PF) synapse. GLAST complexes with the extracellular domain of DSCAM. Riluzole, as an activator of GLAST-mediated uptake, rescues the proximal impairment in CF synapse formation in Purkinje cell-selective Dscam-deficient mice. DSCAM is required for motor learning, but not gross motor coordination. In conclusion, the intercellular association of synaptic and astrocyte proteins is important for synapse formation and function in neural transmission.
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Affiliation(s)
- Ken-Ichi Dewa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan
- Laboratory for Glia-Neuron Circuit Dynamics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Nariko Arimura
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan.
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 980-8578, Tohoku, Japan.
| | - Wataru Kakegawa
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Masayuki Itoh
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Toma Adachi
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Satoshi Miyashita
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
- Department of System Pathology for Neurological Disorders, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Yukiko U Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Kento Hizawa
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 980-8578, Tohoku, Japan
| | - Kei Hori
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Natsumi Honjoya
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 980-8578, Tohoku, Japan
| | - Haruya Yagishita
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 980-8578, Tohoku, Japan
| | - Shinichiro Taya
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
- Division of Behavioural Neuropharmacology, International Center for Brain Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Taisuke Miyazaki
- Department of Health Sciences, School of Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0812, Japan
| | - Chika Usui
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Shoji Tatsumoto
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
| | - Akiko Tsuzuki
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Hirotomo Uetake
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
- Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Saitama, 274-8510, Japan
| | - Kazuhisa Sakai
- Department of Ultrastructural Research, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Kazuhiro Yamakawa
- Department of Neurodevelopmental Disorder Genetics, Nagoya City University Graduate School of Medicine, Nagoya, Aichi, 467-8601, Japan
| | - Takuya Sasaki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 980-8578, Tohoku, Japan
| | - Jun Nagai
- Laboratory for Glia-Neuron Circuit Dynamics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Yoshiya Kawaguchi
- Department of Life Science Frontiers, Center for iPS cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Masaki Sone
- Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Saitama, 274-8510, Japan
| | - Takayoshi Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Yasuhiro Go
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
- Department of System Neuroscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8585, Japan
- Graduate School of Information Science, University of Hyogo, Kobe, Hyogo, 650-0047, Japan
| | - Noritaka Ichinohe
- Department of Ultrastructural Research, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan
| | - Kozo Kaibuchi
- Division of Cell Biology, International Center for Brain Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, 060-8638, Japan
- The University of Texas at Austin, Austin, Texas, 78712-0805, USA
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi, 409-3898, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Mikio Hoshino
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo, 187-8502, Japan.
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6
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Hergenreder T, Yang T, Ye B. The role of Down syndrome cell adhesion molecule in Down syndrome. MEDICAL REVIEW (2021) 2024; 4:31-41. [PMID: 38515781 PMCID: PMC10954295 DOI: 10.1515/mr-2023-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/18/2024] [Indexed: 03/23/2024]
Abstract
Down syndrome (DS) is caused by the presence of an extra copy of the entire or a portion of human chromosome 21 (HSA21). This genomic alteration leads to elevated expression of numerous HSA21 genes, resulting in a variety of health issues in individuals with DS. Among the genes located in the DS "critical region" of HSA21, Down syndrome cell adhesion molecule (DSCAM) plays an important role in neuronal development. There is a growing body of evidence underscoring DSCAM's involvement in various DS-related disorders. This review aims to provide a concise overview of the established functions of DSCAM, with a particular focus on its implications in DS. We delve into the roles that DSCAM plays in DS-associated diseases. In the concluding section of this review, we explore prospective avenues for future research to further unravel DSCAM's role in DS and opportunities for therapeutic treatments.
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Affiliation(s)
- Ty Hergenreder
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Tao Yang
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Bing Ye
- Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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7
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Ustaoglu P, McQuarrie DWJ, Rochet A, Dix TC, Haussmann IU, Arnold R, Devaud JM, Soller M. Memory consolidation in honey bees is enhanced by down-regulation of Down syndrome cell adhesion molecule and changes its alternative splicing. Front Mol Neurosci 2024; 16:1322808. [PMID: 38264345 PMCID: PMC10803435 DOI: 10.3389/fnmol.2023.1322808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/13/2023] [Indexed: 01/25/2024] Open
Abstract
Down syndrome cell adhesion molecule (Dscam) gene encodes a cell adhesion molecule required for neuronal wiring. A remarkable feature of arthropod Dscam is massive alternative splicing generating thousands of different isoforms from three variable clusters of alternative exons. Dscam expression and diversity arising from alternative splicing have been studied during development, but whether they exert functions in adult brains has not been determined. Here, using honey bees, we find that Dscam expression is critically linked to memory retention as reducing expression by RNAi enhances memory after reward learning in adult worker honey bees. Moreover, alternative splicing of Dscam is altered in all three variable clusters after learning. Since identical Dscam isoforms engage in homophilic interactions, these results suggest a mechanism to alter inclusion of variable exons during memory consolidation to modify neuronal connections for memory retention.
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Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - David W. J. McQuarrie
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - Anthony Rochet
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), CNRS, UPS, Toulouse University, Toulouse, France
| | - Thomas C. Dix
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
| | - Irmgard U. Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Life Science, Faculty of Health, Education and Life Sciences, Birmingham City University, Birmingham, United Kingdom
| | - Roland Arnold
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
- College of Medical and Dental Sciences, Institute of Cancer and Genomics Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), CNRS, UPS, Toulouse University, Toulouse, France
- Institut Universitaire de France (IUF), Paris, France
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
- Birmingham Centre for Genome Biology, University of Birmingham, Birmingham, United Kingdom
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8
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Eichler K, Hampel S, Alejandro-García A, Calle-Schuler SA, Santana-Cruz A, Kmecova L, Blagburn JM, Hoopfer ED, Seeds AM. Somatotopic organization among parallel sensory pathways that promote a grooming sequence in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.11.528119. [PMID: 36798384 PMCID: PMC9934617 DOI: 10.1101/2023.02.11.528119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Mechanosensory neurons located across the body surface respond to tactile stimuli and elicit diverse behavioral responses, from relatively simple stimulus location-aimed movements to complex movement sequences. How mechanosensory neurons and their postsynaptic circuits influence such diverse behaviors remains unclear. We previously discovered that Drosophila perform a body location-prioritized grooming sequence when mechanosensory neurons at different locations on the head and body are simultaneously stimulated by dust (Hampel et al., 2017; Seeds et al., 2014). Here, we identify nearly all mechanosensory neurons on the Drosophila head that individually elicit aimed grooming of specific head locations, while collectively eliciting a whole head grooming sequence. Different tracing methods were used to reconstruct the projections of these neurons from different locations on the head to their distinct arborizations in the brain. This provides the first synaptic resolution somatotopic map of a head, and defines the parallel-projecting mechanosensory pathways that elicit head grooming.
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Affiliation(s)
- Katharina Eichler
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
- Contributed equally
| | - Stefanie Hampel
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
- Contributed equally
| | - Adrián Alejandro-García
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
- Contributed equally
| | - Steven A Calle-Schuler
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
| | - Alexis Santana-Cruz
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
| | - Lucia Kmecova
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
- Neuroscience Program, Carleton College, Northfield, Minnesota
- Contributed equally
| | - Jonathan M Blagburn
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
| | - Eric D Hoopfer
- Neuroscience Program, Carleton College, Northfield, Minnesota
| | - Andrew M Seeds
- Institute of Neurobiology, University of Puerto Rico-Medical Sciences Campus, San Juan, Puerto Rico
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9
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Lee S, Aubee JI, Lai EC. Regulation of alternative splicing and polyadenylation in neurons. Life Sci Alliance 2023; 6:e202302000. [PMID: 37793776 PMCID: PMC10551640 DOI: 10.26508/lsa.202302000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023] Open
Abstract
Cell-type-specific gene expression is a fundamental feature of multicellular organisms and is achieved by combinations of regulatory strategies. Although cell-restricted transcription is perhaps the most widely studied mechanism, co-transcriptional and post-transcriptional processes are also central to the spatiotemporal control of gene functions. One general category of expression control involves the generation of multiple transcript isoforms from an individual gene, whose balance and cell specificity are frequently tightly regulated via diverse strategies. The nervous system makes particularly extensive use of cell-specific isoforms, specializing the neural function of genes that are expressed more broadly. Here, we review regulatory strategies and RNA-binding proteins that direct neural-specific isoform processing. These include various classes of alternative splicing and alternative polyadenylation events, both of which broadly diversify the neural transcriptome. Importantly, global alterations of splicing and alternative polyadenylation are characteristic of many neural pathologies, and recent genetic studies demonstrate how misregulation of individual neural isoforms can directly cause mutant phenotypes.
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Affiliation(s)
- Seungjae Lee
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Joseph I Aubee
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, NY, USA
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10
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Yoshikawa S, Tang P, Simpson JH. Mechanosensory and command contributions to the Drosophila grooming sequence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.19.567707. [PMID: 38045358 PMCID: PMC10690200 DOI: 10.1101/2023.11.19.567707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Flies groom in response to competing mechanosensory cues in an anterior to posterior order using specific legs. From behavior screens, we identified a pair of cholinergic command-like neurons, Mago-no-Te (MGT), whose optogenetic activation elicits thoracic grooming by hind legs. Thoracic grooming is typically composed of body sweeps and leg rubs in alternation, but clonal analysis coupled with amputation experiments revealed that MGT activation only commands the body sweeps: initiation of leg rubbing requires contact between leg and thorax. With new electron microscopy (EM) connectome data for the ventral nerve cord (VNC), we uncovered a circuit-based explanation for why stimulation of posterior thoracic mechanosensory bristles initiates cleaning by the hind legs. Our previous work showed that flies weigh mechanosensory inputs across the body to select which part to groom, but we did not know why the thorax was always cleaned last. Here, the connectome for the VNC enabled us to identify a pair of GABAergic inhibitory neurons, UMGT1, that receive diverse sensory inputs and synapse onto both MGT and components of its downstream pre-motor circuits. Optogenetic activation of UMGT1 suppresses thoracic cleaning, representing a mechanism by which mechanosensory stimuli on other body parts could take precedence in the grooming hierarchy. We also mapped the pre-motor circuit downstream of MGT, including inhibitory feedback connections that may enable rhythmicity and coordination of limb movement during thoracic grooming.
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Affiliation(s)
- Shingo Yoshikawa
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Paul Tang
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Julie H. Simpson
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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11
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Dong H, Yang X, Wu L, Zhang S, Zhang J, Guo P, Du Y, Pan C, Fu Y, Li L, Shi J, Zhu Y, Ma H, Bian L, Xu B, Li G, Shi F, Huang J, He H, Jin Y. A systematic CRISPR screen reveals redundant and specific roles for Dscam1 isoform diversity in neuronal wiring. PLoS Biol 2023; 21:e3002197. [PMID: 37410725 DOI: 10.1371/journal.pbio.3002197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 06/13/2023] [Indexed: 07/08/2023] Open
Abstract
Drosophila melanogaster Down syndrome cell adhesion molecule 1 (Dscam1) encodes 19,008 diverse ectodomain isoforms via the alternative splicing of exon 4, 6, and 9 clusters. However, whether individual isoforms or exon clusters have specific significance is unclear. Here, using phenotype-diversity correlation analysis, we reveal the redundant and specific roles of Dscam1 diversity in neuronal wiring. A series of deletion mutations were performed from the endogenous locus harboring exon 4, 6, or 9 clusters, reducing to 396 to 18,612 potential ectodomain isoforms. Of the 3 types of neurons assessed, dendrite self/non-self discrimination required a minimum number of isoforms (approximately 2,000), independent of exon clusters or isoforms. In contrast, normal axon patterning in the mushroom body and mechanosensory neurons requires many more isoforms that tend to associate with specific exon clusters or isoforms. We conclude that the role of the Dscam1 diversity in dendrite self/non-self discrimination is nonspecifically mediated by its isoform diversity. In contrast, a separate role requires variable domain- or isoform-related functions and is essential for other neurodevelopmental contexts, such as axonal growth and branching. Our findings shed new light on a general principle for the role of Dscam1 diversity in neuronal wiring.
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Affiliation(s)
- Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xi Yang
- Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Lili Wu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Pengjuan Guo
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yiwen Du
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Changkun Pan
- Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yanda Zhu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongru Ma
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lina Bian
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianhua Huang
- Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang, China, PR China
| | - Haihuai He
- Department of Neurosurgery, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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12
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Zhang S, Yang X, Dong H, Xu B, Wu L, Zhang J, Li G, Guo P, Li L, Fu Y, Du Y, Zhu Y, Shi J, Shi F, Huang J, He H, Jin Y. Cis mutagenesis in vivo reveals extensive noncanonical functions of Dscam1 isoforms in neuronal wiring. PNAS NEXUS 2023; 2:pgad135. [PMID: 37152679 PMCID: PMC10156172 DOI: 10.1093/pnasnexus/pgad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 05/09/2023]
Abstract
Drosophila Down syndrome cell adhesion molecule 1 (Dscam1) encodes tens of thousands of cell recognition molecules via alternative splicing, which are required for neural function. A canonical self-avoidance model seems to provide a central mechanistic basis for Dscam1 functions in neuronal wiring. Here, we reveal extensive noncanonical functions of Dscam1 isoforms in neuronal wiring. We generated a series of allelic cis mutations in Dscam1, encoding a normal number of isoforms, but with an altered isoform composition. Despite normal dendritic self-avoidance and self-/nonself-discrimination in dendritic arborization (da) neurons, which is consistent with the canonical self-avoidance model, these mutants exhibited strikingly distinct spectra of phenotypic defects in the three types of neurons: up to ∼60% defects in mushroom bodies, a significant increase in branching and growth in da neurons, and mild axonal branching defects in mechanosensory neurons. Remarkably, the altered isoform composition resulted in increased dendrite growth yet inhibited axon growth. Moreover, reducing Dscam1 dosage exacerbated axonal defects in mushroom bodies and mechanosensory neurons but reverted dendritic branching and growth defects in da neurons. This splicing-tuned regulation strategy suggests that axon and dendrite growth in diverse neurons cell-autonomously require Dscam1 isoform composition. These findings provide important insights into the functions of Dscam1 isoforms in neuronal wiring.
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Affiliation(s)
| | | | - Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Lili Wu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Pengjuan Guo
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Yiwen Du
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Yanda Zhu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou ZJ310058, People's Republic of China
| | - Jianhua Huang
- Institute of Insect Sciences, Zhejiang University, Hangzhou ZJ310058, People’s Republic of China
| | - Haihuai He
- To whom correspondence should be addressed: (H.H.); (Y.J.)
| | - Yongfeng Jin
- To whom correspondence should be addressed: (H.H.); (Y.J.)
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13
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Neuronal and astrocytic protein connections and associated adhesion molecules. Neurosci Res 2023; 187:14-20. [PMID: 36202350 DOI: 10.1016/j.neures.2022.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 08/12/2022] [Accepted: 09/27/2022] [Indexed: 02/11/2023]
Abstract
Astrocytes are morphologically complex, with a myriad of processes which allow contact with other astrocytes, blood vessels, and neurons. Adhesion molecules expressed by these cells regulate this connectivity. Adhesion molecules are required to form and maintain functional neural circuits, but their importance and mechanisms of action, particularly in astrocyte-neuron contact, remain unresolved. Several studies of neuron-astrocyte connections have demonstrated the vital functions of adhesion molecules, including neuron-glia cell adhesion molecules, astrotactins, and protocadherins. In this review, we provide an overview and perspective of astrocyte-neuron contacts mediated by adhesion molecules in developing neural circuits and synapse formation, especially in the cerebellum. We also outline a novel mechanism of interaction between neurons and astrocytes in the tripartite synapses that has been recently found by our group.
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14
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Hernández K, Godoy L, Newquist G, Kellermeyer R, Alavi M, Mathew D, Kidd T. Dscam1 overexpression impairs the function of the gut nervous system in Drosophila. Dev Dyn 2023; 252:156-171. [PMID: 36454543 PMCID: PMC9812936 DOI: 10.1002/dvdy.554] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 11/04/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Down syndrome (DS) patients have a 100-fold increase in the risk of Hirschsprung syndrome of the colon and rectum (HSCR), a lack of enteric neurons in the colon. The leading DS candidate gene is trisomy of the Down syndrome cell adhesion molecule (DSCAM). RESULTS We find that Dscam1 protein is expressed in the Drosophila enteric/stomatogastric nervous system (SNS). Axonal Dscam1 phenotypes can be rescued equally by diverse isoforms. Overexpression of Dscam1 resulted in frontal and hindgut nerve overgrowth. Expression of dominant negative Dscam1-ΔC led to a truncated frontal nerve and increased branching of the hindgut nerve. Larval locomotion is influenced by feeding state, and we found that the average speed of larvae with Dscam1 SNS expression was reduced, whereas overexpression of Dscam1-ΔC significantly increased the speed. Dscam1 overexpression reduced the efficiency of food clearance from the larval gut. CONCLUSION Our work demonstrates that overexpression of Dscam1 can perturb gut function in a model system.
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Affiliation(s)
| | - Luis Godoy
- Biology/MS 314, University of Nevada, Reno, NV 89557, USA
| | | | | | - Maryam Alavi
- Biology/MS 314, University of Nevada, Reno, NV 89557, USA
| | - Dennis Mathew
- Biology/MS 314, University of Nevada, Reno, NV 89557, USA
| | - Thomas Kidd
- Biology/MS 314, University of Nevada, Reno, NV 89557, USA
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15
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Duhart JC, Mosca TJ. Genetic regulation of central synapse formation and organization in Drosophila melanogaster. Genetics 2022; 221:6597078. [PMID: 35652253 DOI: 10.1093/genetics/iyac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 01/04/2023] Open
Abstract
A goal of modern neuroscience involves understanding how connections in the brain form and function. Such a knowledge is essential to inform how defects in the exquisite complexity of nervous system growth influence neurological disease. Studies of the nervous system in the fruit fly Drosophila melanogaster enabled the discovery of a wealth of molecular and genetic mechanisms underlying development of synapses-the specialized cell-to-cell connections that comprise the essential substrate for information flow and processing in the nervous system. For years, the major driver of knowledge was the neuromuscular junction due to its ease of examination. Analogous studies in the central nervous system lagged due to a lack of genetic accessibility of specific neuron classes, synaptic labels compatible with cell-type-specific access, and high resolution, quantitative imaging strategies. However, understanding how central synapses form remains a prerequisite to understanding brain development. In the last decade, a host of new tools and techniques extended genetic studies of synapse organization into central circuits to enhance our understanding of synapse formation, organization, and maturation. In this review, we consider the current state-of-the-field. We first discuss the tools, technologies, and strategies developed to visualize and quantify synapses in vivo in genetically identifiable neurons of the Drosophila central nervous system. Second, we explore how these tools enabled a clearer understanding of synaptic development and organization in the fly brain and the underlying molecular mechanisms of synapse formation. These studies establish the fly as a powerful in vivo genetic model that offers novel insights into neural development.
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Affiliation(s)
- Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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16
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Self-avoidance alone does not explain the function of Dscam1 in mushroom body axonal wiring. Curr Biol 2022; 32:2908-2920.e4. [PMID: 35659864 DOI: 10.1016/j.cub.2022.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/28/2022] [Accepted: 05/11/2022] [Indexed: 11/24/2022]
Abstract
Alternative splicing of Drosophila Dscam1 into 38,016 isoforms provides neurons with a unique molecular code for self-recognition and self-avoidance. A canonical model suggests that the homophilic binding of identical Dscam1 isoforms on the sister branches of mushroom body (MB) axons supports segregation with high fidelity, even when only a single isoform is expressed. Here, we generated a series of mutant flies with a single exon 4, 6, or 9 variant, encoding 1,584, 396, or 576 potential isoforms, respectively. Surprisingly, most of the mutants in the latter two groups exhibited obvious defects in the growth, branching, and segregation of MB axonal sister branches. This demonstrates that the repertoires of 396 and 576 Dscam1 isoforms were not sufficient for the normal patterning of axonal branches. Moreover, reducing Dscam1 levels largely reversed the defects caused by reduced isoform diversity, suggesting a functional link between Dscam1 expression levels and isoform diversity. Taken together, these results indicate that canonical self-avoidance alone does not explain the function of Dscam1 in MB axonal wiring.
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17
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Dong H, Xu B, Guo P, Zhang J, Yang X, Li L, Fu Y, Shi J, Zhang S, Zhu Y, Shi Y, Zhou F, Bian L, You W, Shi F, Yang X, Huang J, He H, Jin Y. Hidden RNA pairings counteract the "first-come, first-served" splicing principle to drive stochastic choice in Dscam1 splice variants. SCIENCE ADVANCES 2022; 8:eabm1763. [PMID: 35080968 PMCID: PMC8791459 DOI: 10.1126/sciadv.abm1763] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Drosophila melanogaster Dscam1 encodes 38,016 isoforms via mutually exclusive splicing; however, the regulatory mechanism behind this is not fully understood. Here, we found a set of hidden RNA secondary structures that balance the stochastic choice of Dscam1 splice variants (designated balancer RNA secondary structures). In vivo mutational analyses revealed the dual function of these balancer interactions in driving the stochastic choice of splice variants, through enhancement of the inclusion of distal exon 6s by cooperating with docking site–selector pairing to form a stronger multidomain pre-mRNA structure and through simultaneous repression of the inclusion of proximal exon 6s by antagonizing their docking site–selector pairings. Thus, we provide an elegant molecular model based on competition and cooperation between two sets of docking site–selector and balancer pairings, which counteracts the “first-come, first-served” principle. Our findings provide conceptual and mechanistic insight into the dynamics and functions of long-range RNA secondary structures.
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Affiliation(s)
- Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Pengjuan Guo
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xi Yang
- Department of Neurosurgery and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yanda Zhu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yang Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Fengyan Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lina Bian
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Wendong You
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Xiaofeng Yang
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jianhua Huang
- Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Haihuai He
- Department of Neurosurgery and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, China
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18
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Williams DL, Sikora VM, Hammer MA, Amin S, Brinjikji T, Brumley EK, Burrows CJ, Carrillo PM, Cromer K, Edwards SJ, Emri O, Fergle D, Jenkins MJ, Kaushik K, Maydan DD, Woodard W, Clowney EJ. May the Odds Be Ever in Your Favor: Non-deterministic Mechanisms Diversifying Cell Surface Molecule Expression. Front Cell Dev Biol 2022; 9:720798. [PMID: 35087825 PMCID: PMC8787164 DOI: 10.3389/fcell.2021.720798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 11/24/2021] [Indexed: 12/30/2022] Open
Abstract
How does the information in the genome program the functions of the wide variety of cells in the body? While the development of biological organisms appears to follow an explicit set of genomic instructions to generate the same outcome each time, many biological mechanisms harness molecular noise to produce variable outcomes. Non-deterministic variation is frequently observed in the diversification of cell surface molecules that give cells their functional properties, and is observed across eukaryotic clades, from single-celled protozoans to mammals. This is particularly evident in immune systems, where random recombination produces millions of antibodies from only a few genes; in nervous systems, where stochastic mechanisms vary the sensory receptors and synaptic matching molecules produced by different neurons; and in microbial antigenic variation. These systems employ overlapping molecular strategies including allelic exclusion, gene silencing by constitutive heterochromatin, targeted double-strand breaks, and competition for limiting enhancers. Here, we describe and compare five stochastic molecular mechanisms that produce variety in pathogen coat proteins and in the cell surface receptors of animal immune and neuronal cells, with an emphasis on the utility of non-deterministic variation.
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Affiliation(s)
- Donnell L. Williams
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
| | - Veronica Maria Sikora
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Max A. Hammer
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Sayali Amin
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Taema Brinjikji
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Emily K. Brumley
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Connor J. Burrows
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Paola Michelle Carrillo
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Kirin Cromer
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Summer J. Edwards
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Olivia Emri
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Daniel Fergle
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - M. Jamal Jenkins
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
| | - Krishangi Kaushik
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Daniella D. Maydan
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - Wrenn Woodard
- MCDB 464 – Cellular Diversity in the Immune and Nervous Systems, University of Michigan, Ann Arbor, MI, United States
| | - E. Josephine Clowney
- Department of Molecular, Cellular and Developmental Biology, The University of Michigan, Ann Arbor, MI, United States
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19
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Schmidt A, Schreiner D. Quantitative Detection of Protein Splice Variants by Selected Reaction Monitoring (SRM) Mass Spectrometry. Methods Mol Biol 2022; 2537:231-246. [PMID: 35895268 DOI: 10.1007/978-1-0716-2521-7_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular diversification of the cellular proteome through alternative splicing has emerged as an important biological principle. However, the lack of tools to specifically detect and quantify proteoforms (Smith et al., Nat Methods 10:186-187, 2013) is a major impediment to functional studies. Recently, biological mass spectrometry (MS) has undergone impressive advances (Mann, Nat Rev Mol Cell Biol 17:678, 2016), including the generation of a highly diverse set of biological applications (Aebersold and Mann, Nature 537:347-355, 2016), and has demonstrated to be an essential tool to address many biological questions (Savitski et al., Science 346:1255784, 2014; Rinner et al., Nat Methods 5:315-318, 2008). In particular, targeted LC-MS, with its high selectivity and specificity, is ideally suited for the precise and sensitive quantification of specific proteins and their proteoforms (Picotti and Aebersold, Nat Methods 9:555-566, 2012). We describe in detail the application of this workflow applied to dissect the molecular diversity of the synaptic adhesion proteins and their splicing-derived proteoforms (Schreiner et al., Elife 4:e07794, 2015).
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20
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Ivanov TM, Pervouchine DD. Tandem Exon Duplications Expanding the Alternative Splicing Repertoire. Acta Naturae 2022; 14:73-81. [PMID: 35441045 PMCID: PMC9013439 DOI: 10.32607/actanaturae.11583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/17/2022] [Indexed: 11/20/2022] Open
Abstract
Tandem exon duplications play an important role in the evolution of eukaryotic genes, providing a generic mechanism for adaptive regulation of protein function. In recent studies, tandem exon duplications have been linked to mutually exclusive exon choice, a pattern of alternative splicing in which one and only one exon from a group of tandemly arranged exons is included in the mature transcript. Here, we revisit the problem of identifying tandem exon duplications in eukaryotic genomes using bioinformatic methods and show that tandemly duplicated exons are abundant not only in the coding parts, but also in the untranslated regions. We present a number of remarkable examples of tandem exon duplications, identify unannotated duplicated exons, and provide statistical support for their expression using large panels of RNA-seq experiments.
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Affiliation(s)
- T. M. Ivanov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
| | - D. D. Pervouchine
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 121205 Russia
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21
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Genes Associated with Disturbed Cerebral Neurogenesis in the Embryonic Brain of Mouse Models of Down Syndrome. Genes (Basel) 2021; 12:genes12101598. [PMID: 34680993 PMCID: PMC8535956 DOI: 10.3390/genes12101598] [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] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 02/06/2023] Open
Abstract
Down syndrome (DS), also known as trisomy 21, is the most frequent genetic cause of intellectual disability. Although the mechanism remains unknown, delayed brain development is assumed to be involved in DS intellectual disability. Analyses with human with DS and mouse models have shown that defects in embryonic cortical neurogenesis may lead to delayed brain development. Cre-loxP-mediated chromosomal engineering has allowed the generation of a variety of mouse models carrying various partial Mmu16 segments. These mouse models are useful for determining genotype–phenotype correlations and identifying dosage-sensitive genes involved in the impaired neurogenesis. In this review, we summarize several candidate genes and pathways that have been linked to defective cortical neurogenesis in DS.
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22
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Structure of cell-cell adhesion mediated by the Down syndrome cell adhesion molecule. Proc Natl Acad Sci U S A 2021; 118:2022442118. [PMID: 34531300 DOI: 10.1073/pnas.2022442118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2021] [Indexed: 11/18/2022] Open
Abstract
The Down syndrome cell adhesion molecule (DSCAM) belongs to the immunoglobulin superfamily (IgSF) and plays important roles in neural development. It has a large ectodomain, including 10 Ig-like domains and 6 fibronectin III (FnIII) domains. Previous data have shown that DSCAM can mediate cell adhesion by forming homophilic dimers between cells and contributes to self-avoidance of neurites or neuronal tiling, which is important for neural network formation. However, the organization and assembly of DSCAM at cell adhesion interfaces has not been fully understood. Here we combine electron microscopy and other biophysical methods to characterize the structure of the DSCAM-mediated cell adhesion and generate three-dimensional views of the adhesion interfaces of DSCAM by electron tomography. The results show that mouse DSCAM forms a regular pattern at the adhesion interfaces. The Ig-like domains contribute to both trans homophilic interactions and cis assembly of the pattern, and the FnIII domains are crucial for the cis pattern formation as well as the interaction with the cell membrane. By contrast, no obvious assembly pattern is observed at the adhesion interfaces mediated by mouse DSCAML1 or Drosophila DSCAMs, suggesting the different structural roles and mechanisms of DSCAMs in mediating cell adhesion and neural network formation.
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23
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Izadifar A, Courchet J, Virga DM, Verreet T, Hamilton S, Ayaz D, Misbaer A, Vandenbogaerde S, Monteiro L, Petrovic M, Sachse S, Yan B, Erfurth ML, Dascenco D, Kise Y, Yan J, Edwards-Faret G, Lewis T, Polleux F, Schmucker D. Axon morphogenesis and maintenance require an evolutionary conserved safeguard function of Wnk kinases antagonizing Sarm and Axed. Neuron 2021; 109:2864-2883.e8. [PMID: 34384519 DOI: 10.1016/j.neuron.2021.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 05/24/2021] [Accepted: 07/08/2021] [Indexed: 12/13/2022]
Abstract
The molecular and cellular mechanisms underlying complex axon morphogenesis are still poorly understood. We report a novel, evolutionary conserved function for the Drosophila Wnk kinase (dWnk) and its mammalian orthologs, WNK1 and 2, in axon branching. We uncover that dWnk, together with the neuroprotective factor Nmnat, antagonizes the axon-destabilizing factors D-Sarm and Axundead (Axed) during axon branch growth, revealing a developmental function for these proteins. Overexpression of D-Sarm or Axed results in axon branching defects, which can be blocked by overexpression of dWnk or Nmnat. Surprisingly, Wnk kinases are also required for axon maintenance of adult Drosophila and mouse cortical pyramidal neurons. Requirement of Wnk for axon maintenance is independent of its developmental function. Inactivation of dWnk or mouse Wnk1/2 in mature neurons leads to axon degeneration in the adult brain. Therefore, Wnk kinases are novel signaling components that provide a safeguard function in both developing and adult axons.
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Affiliation(s)
- Azadeh Izadifar
- Life and Medical Sciences Institute (LIMES), Bonn, Germany; VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Julien Courchet
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, 69622 Villeurbanne, France; Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| | - Daniel M Virga
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Tine Verreet
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Stevie Hamilton
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Derya Ayaz
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Anke Misbaer
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Sofie Vandenbogaerde
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Laloe Monteiro
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5310, INSERM U-1217, Institut NeuroMyoGène, 69622 Villeurbanne, France
| | - Milan Petrovic
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Sonja Sachse
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Bing Yan
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Maria-Luise Erfurth
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Dan Dascenco
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Jiekun Yan
- VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Gabriela Edwards-Faret
- Life and Medical Sciences Institute (LIMES), Bonn, Germany; VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Tommy Lewis
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Franck Polleux
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA; Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
| | - Dietmar Schmucker
- Life and Medical Sciences Institute (LIMES), Bonn, Germany; VIB Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, KU Leuven, Leuven, Belgium.
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24
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Hong W, Zhang J, Dong H, Shi Y, Ma H, Zhou F, Xu B, Fu Y, Zhang S, Hou S, Li G, Wu Y, Chen S, Zhu X, You W, Shi F, Yang X, Gong Z, Huang J, Jin Y. Intron-targeted mutagenesis reveals roles for Dscam1 RNA pairing architecture-driven splicing bias in neuronal wiring. Cell Rep 2021; 36:109373. [PMID: 34260933 DOI: 10.1016/j.celrep.2021.109373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/05/2021] [Accepted: 06/18/2021] [Indexed: 12/28/2022] Open
Abstract
Drosophila melanogaster Down syndrome cell adhesion molecule (Dscam1) can generate 38,016 different isoforms through largely stochastic, yet highly biased, alternative splicing. These isoforms are required for nervous functions. However, the functional significance of splicing bias remains unknown. Here, we provide evidence that Dscam1 splicing bias is required for mushroom body (MB) axonal wiring. We generate mutant flies with normal overall protein levels and an identical number but global changes in exon 4 and 9 isoform bias (DscamΔ4D-/- and DscamΔ9D-/-), respectively. In contrast to DscamΔ4D-/-, DscamΔ9D-/- exhibits remarkable MB defects, suggesting a variable domain-specific requirement for isoform bias. Importantly, changes in isoform bias cause axonal defects but do not influence the self-avoidance of axonal branches. We conclude that, in contrast to the isoform number that provides the molecular basis for neurite self-avoidance, isoform bias may play a role in MB axonal wiring by influencing non-repulsive signaling.
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Affiliation(s)
- Weiling Hong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Jian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yang Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Hongru Ma
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Fengyan Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Shouqing Hou
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yandan Wu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Shuo Chen
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Xiaohua Zhu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Wendong You
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Xiaofeng Yang
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Zhefeng Gong
- Department of Neuroscience, School of Medicine, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Jianhua Huang
- Institute of Insect Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China; Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China.
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25
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Tang XY, Xu L, Wang J, Hong Y, Wang Y, Zhu Q, Wang D, Zhang XY, Liu CY, Fang KH, Han X, Wang S, Wang X, Xu M, Bhattacharyya A, Guo X, Lin M, Liu Y. DSCAM/PAK1 pathway suppression reverses neurogenesis deficits in iPSC-derived cerebral organoids from patients with Down syndrome. J Clin Invest 2021; 131:135763. [PMID: 33945512 DOI: 10.1172/jci135763] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/28/2021] [Indexed: 12/22/2022] Open
Abstract
Down syndrome (DS), caused by trisomy of chromosome 21, occurs in 1 of every 800 live births. Early defects in cortical development likely account for the cognitive impairments in DS, although the underlying molecular mechanism remains elusive. Here, we performed histological assays and unbiased single-cell RNA-Seq (scRNA-Seq) analysis on cerebral organoids derived from 4 euploid cell lines and from induced pluripotent stem cells (iPSCs) from 3 individuals with trisomy 21 to explore cell-type-specific abnormalities associated with DS during early brain development. We found that neurogenesis was significantly affected, given the diminished proliferation and decreased expression of layer II and IV markers in cortical neurons in the subcortical regions; this may have been responsible for the reduced size of the organoids. Furthermore, suppression of the DSCAM/PAK1 pathway, which showed enhanced activity in DS, using CRISPR/Cas9, CRISPR interference (CRISPRi), or small-molecule inhibitor treatment reversed abnormal neurogenesis, thereby increasing the size of organoids derived from DS iPSCs. Our study demonstrates that 3D cortical organoids developed in vitro are a valuable model of DS and provide a direct link between dysregulation of the DSCAM/PAK1 pathway and developmental brain defects in DS.
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Affiliation(s)
- Xiao-Yan Tang
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Lei Xu
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Jingshen Wang
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuan Hong
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Yuanyuan Wang
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qian Zhu
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Da Wang
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Xin-Yue Zhang
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Chun-Yue Liu
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Kai-Heng Fang
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Xiao Han
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Shihua Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xin Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Min Xu
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
| | - Anita Bhattacharyya
- Waisman Center and.,Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
| | - Xing Guo
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China.,Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Mingyan Lin
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yan Liu
- Department of Stem Cell and Neural Regeneration, State Key Laboratory of Reproductive Medicine, School of Pharmacy, and
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26
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Abstract
Neurons develop dendritic morphologies that bear cell type-specific features in dendritic field size and geometry, branch placement and density, and the types and distributions of synaptic contacts. Dendritic patterns influence the types and numbers of inputs a neuron receives, and the ways in which neural information is processed and transmitted in the circuitry. Even subtle alterations in dendritic structures can have profound consequences on neuronal function and are implicated in neurodevelopmental disorders. In this chapter, I review how growing dendrites acquire their exquisite patterns by drawing examples from diverse neuronal cell types in vertebrate and invertebrate model systems. Dendrite morphogenesis is shaped by intrinsic and extrinsic factors such as transcriptional regulators, guidance and adhesion molecules, neighboring cells and synaptic partners. I discuss molecular mechanisms that regulate dendrite morphogenesis with a focus on five aspects of dendrite patterning: (1) Dendritic cytoskeleton and cellular machineries that build the arbor; (2) Gene regulatory mechanisms; (3) Afferent cues that regulate dendritic arbor growth; (4) Space-filling strategies that optimize dendritic coverage; and (5) Molecular cues that specify dendrite wiring. Cell type-specific implementation of these patterning mechanisms produces the diversity of dendrite morphologies that wire the nervous system.
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27
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Mitsogiannis MD, Pancho A, Aerts T, Sachse SM, Vanlaer R, Noterdaeme L, Schmucker D, Seuntjens E. Subtle Roles of Down Syndrome Cell Adhesion Molecules in Embryonic Forebrain Development and Neuronal Migration. Front Cell Dev Biol 2021; 8:624181. [PMID: 33585465 PMCID: PMC7876293 DOI: 10.3389/fcell.2020.624181] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/22/2020] [Indexed: 12/26/2022] Open
Abstract
Down Syndrome (DS) Cell Adhesion Molecules (DSCAMs) are transmembrane proteins of the immunoglobulin superfamily. Human DSCAM is located within the DS critical region of chromosome 21 (duplicated in Down Syndrome patients), and mutations or copy-number variations of this gene have also been associated to Fragile X syndrome, intellectual disability, autism, and bipolar disorder. The DSCAM paralogue DSCAM-like 1 (DSCAML1) maps to chromosome 11q23, implicated in the development of Jacobsen and Tourette syndromes. Additionally, a spontaneous mouse DSCAM deletion leads to motor coordination defects and seizures. Previous research has revealed roles for DSCAMs in several neurodevelopmental processes, including synaptogenesis, dendritic self-avoidance, cell sorting, axon growth and branching. However, their functions in embryonic mammalian forebrain development have yet to be completely elucidated. In this study, we revealed highly dynamic spatiotemporal patterns of Dscam and Dscaml1 expression in definite cortical layers of the embryonic mouse brain, as well as in structures and ganglionic eminence-derived neural populations within the embryonic subpallium. However, an in-depth histological analysis of cortical development, ventral forebrain morphogenesis, cortical interneuron migration, and cortical-subcortical connectivity formation processes in Dscam and Dscaml1 knockout mice (Dscam del17 and Dscaml1 GT ) at several embryonic stages indicated that constitutive loss of Dscam and Dscaml1 does not affect these developmental events in a significant manner. Given that several Dscam- and Dscaml1-linked neurodevelopmental disorders are associated to chromosomal region duplication events, we furthermore sought to examine the neurodevelopmental effects of Dscam and Dscaml1 gain of function (GOF). In vitro, ex vivo, and in vivo GOF negatively impacted neural migration processes important to cortical development, and affected the morphology of maturing neurons. Overall, these findings contribute to existing knowledge on the molecular etiology of human neurodevelopmental disorders by elucidating how dosage variations of genes encoding adhesive cues can disrupt cell-cell or cell-environment interactions crucial for neuronal migration.
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Affiliation(s)
- Manuela D. Mitsogiannis
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Anna Pancho
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Tania Aerts
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Sonja M. Sachse
- Neuronal Wiring Laboratory, Department of Neurosciences, VIB-KU Leuven Center for Brain & Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Ria Vanlaer
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Lut Noterdaeme
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Dietmar Schmucker
- Neuronal Wiring Laboratory, Department of Neurosciences, VIB-KU Leuven Center for Brain & Disease Research, Katholieke Universiteit Leuven, Leuven, Belgium
- Neuronal Wiring Group, Life & Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Eve Seuntjens
- Developmental Neurobiology Group, Animal Physiology and Neurobiology Division, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
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28
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Arimura N, Okada M, Taya S, Dewa KI, Tsuzuki A, Uetake H, Miyashita S, Hashizume K, Shimaoka K, Egusa S, Nishioka T, Yanagawa Y, Yamakawa K, Inoue YU, Inoue T, Kaibuchi K, Hoshino M. DSCAM regulates delamination of neurons in the developing midbrain. SCIENCE ADVANCES 2020; 6:6/36/eaba1693. [PMID: 32917586 PMCID: PMC7467692 DOI: 10.1126/sciadv.aba1693] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 07/22/2020] [Indexed: 06/10/2023]
Abstract
For normal neurogenesis and circuit formation, delamination of differentiating neurons from the proliferative zone must be precisely controlled; however, the regulatory mechanisms underlying cell attachment are poorly understood. Here, we show that Down syndrome cell adhesion molecule (DSCAM) controls neuronal delamination by local suppression of the RapGEF2-Rap1-N-cadherin cascade at the apical endfeet in the dorsal midbrain. Dscam transcripts were expressed in differentiating neurons, and DSCAM protein accumulated at the distal part of the apical endfeet. Cre-loxP-based neuronal labeling revealed that Dscam knockdown impaired endfeet detachment from ventricles. DSCAM associated with RapGEF2 to inactivate Rap1, whose activity is required for membrane localization of N-cadherin. Correspondingly, Dscam knockdown increased N-cadherin localization and ventricular attachment area at the endfeet. Furthermore, excessive endfeet attachment by Dscam knockdown was restored by co-knockdown of RapGEF2 or N-cadherin Our findings shed light on the molecular mechanism that regulates a critical step in early neuronal development.
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Affiliation(s)
- Nariko Arimura
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
| | - Mako Okada
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Shinichiro Taya
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Ken-Ichi Dewa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
| | - Akiko Tsuzuki
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Hirotomo Uetake
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
- Department of Biomolecular Science, Faculty of Science, Toho University, Chiba, Japan
| | - Satoshi Miyashita
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Koichi Hashizume
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Kazumi Shimaoka
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Saki Egusa
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Tomoki Nishioka
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Kazuhiro Yamakawa
- Department of Neurodevelopmental Disorder Genetics, Nagoya City University Graduate School of Medicine, Nagoya, Japan
| | - Yukiko U Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Takayoshi Inoue
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Japan
- Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Mikio Hoshino
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
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29
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Sanes JR, Zipursky SL. Synaptic Specificity, Recognition Molecules, and Assembly of Neural Circuits. Cell 2020; 181:536-556. [DOI: 10.1016/j.cell.2020.04.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/23/2020] [Accepted: 04/06/2020] [Indexed: 01/02/2023]
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30
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Barabási DL, Barabási AL. A Genetic Model of the Connectome. Neuron 2020; 105:435-445.e5. [PMID: 31806491 PMCID: PMC7007360 DOI: 10.1016/j.neuron.2019.10.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/07/2019] [Accepted: 10/24/2019] [Indexed: 11/18/2022]
Abstract
The connectomes of organisms of the same species show remarkable architectural and often local wiring similarity, raising the question: where and how is neuronal connectivity encoded? Here, we start from the hypothesis that the genetic identity of neurons guides synapse and gap-junction formation and show that such genetically driven wiring predicts the existence of specific biclique motifs in the connectome. We identify a family of large, statistically significant biclique subgraphs in the connectomes of three species and show that within many of the observed bicliques the neurons share statistically significant expression patterns and morphological characteristics, supporting our expectation of common genetic factors that drive the synapse formation within these subgraphs. The proposed connectome model offers a self-consistent framework to link the genetics of an organism to the reproducible architecture of its connectome, offering experimentally falsifiable predictions on the genetic factors that drive the formation of individual neuronal circuits.
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Affiliation(s)
| | - Albert-László Barabási
- Network Science Institute, Northeastern University, Boston, MA 02115, USA; Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Data and Network Science, Central European University, Budapest 1051, Hungary.
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31
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Roig-Puiggros S, Vigouroux RJ, Beckman D, Bocai NI, Chiou B, Davimes J, Gomez G, Grassi S, Hoque A, Karikari TK, Kiffer F, Lopez M, Lunghi G, Mazengenya P, Meier S, Olguín-Albuerne M, Oliveira MM, Paraíso-Luna J, Pradhan J, Radiske A, Ramos-Hryb AB, Ribeiro MC, Schellino R, Selles MC, Singh S, Theotokis P, Chédotal A. Construction and reconstruction of brain circuits: normal and pathological axon guidance. J Neurochem 2019; 153:10-32. [PMID: 31630412 DOI: 10.1111/jnc.14900] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 02/06/2023]
Abstract
Perception of our environment entirely depends on the close interaction between the central and peripheral nervous system. In order to communicate each other, both systems must develop in parallel and in coordination. During development, axonal projections from the CNS as well as the PNS must extend over large distances to reach their appropriate target cells. To do so, they read and follow a series of axon guidance molecules. Interestingly, while these molecules play critical roles in guiding developing axons, they have also been shown to be critical in other major neurodevelopmental processes, such as the migration of cortical progenitors. Currently, a major hurdle for brain repair after injury or neurodegeneration is the absence of axonal regeneration in the mammalian CNS. By contrasts, PNS axons can regenerate. Many hypotheses have been put forward to explain this paradox but recent studies suggest that hacking neurodevelopmental mechanisms may be the key to promote CNS regeneration. Here we provide a seminar report written by trainees attending the second Flagship school held in Alpbach, Austria in September 2018 organized by the International Society for Neurochemistry (ISN) together with the Journal of Neurochemistry (JCN). This advanced school has brought together leaders in the fields of neurodevelopment and regeneration in order to discuss major keystones and future challenges in these respective fields.
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Affiliation(s)
| | - Robin J Vigouroux
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Danielle Beckman
- California National Primate Research Center, UC Davis, Davis, California, USA
| | - Nadia I Bocai
- Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.,Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Brian Chiou
- Department of Pediatrics, University of California - San Francisco, San Francisco, California, USA
| | - Joshua Davimes
- Faculty of Health Sciences School of Anatomical Sciences, University of the Witwatersrand, Parktown Johannesburg, South Africa
| | - Gimena Gomez
- Laboratorio de Parkinson Experimental, Instituto de Investigaciones Farmacológicas (ININFA-CONICET-UBA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Sara Grassi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Ashfaqul Hoque
- Metabolic Signalling Laboratory, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Thomas K Karikari
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,School of Life Sciences, University of Warwick, Coventry, UK.,Midlands Integrative Biosciences Training Partnership, University of Warwick, Coventry, UK
| | - Frederico Kiffer
- Division of Radiation Health, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.,Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Mary Lopez
- Institute for Stroke and Dementia Research, LMU Munich, Munich, Germany
| | - Giulia Lunghi
- Department of Medical Biotechnology and Translational Medicin, University of Milano, Segrate, Italy
| | - Pedzisai Mazengenya
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Sonja Meier
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland, Australia
| | - Mauricio Olguín-Albuerne
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Mauricio M Oliveira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Juan Paraíso-Luna
- Ramón y Cajal Institute of Health Research (IRYCIS), Department of Biochemistry and Molecular Biology and University Research Institute in Neurochemistry (IUIN), Complutense University, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Jonu Pradhan
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Andressa Radiske
- Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Ana Belén Ramos-Hryb
- Instituto de Biología y Medicina Experimental (IBYME)-CONICET, Buenos Aires, Argentina.,Grupo de Neurociencia de Sistemas, Instituto de Fisiología y Biofísica (IFIBIO) Bernardo Houssay, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
| | - Mayara C Ribeiro
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Roberta Schellino
- Neuroscience Department "Rita Levi-Montalcini" and Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Torino, Italy
| | - Maria Clara Selles
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Shripriya Singh
- System Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Paschalis Theotokis
- Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Thessaloniki, Macedonia, Greece
| | - Alain Chédotal
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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32
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Xu B, Shi Y, Wu Y, Meng Y, Jin Y. Role of RNA secondary structures in regulating Dscam alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194381. [DOI: 10.1016/j.bbagrm.2019.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 12/19/2022]
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Dos Santos JV, Yu RY, Terceros A, Chen BE. FGF receptors are required for proper axonal branch targeting in Drosophila. Mol Brain 2019; 12:84. [PMID: 31651328 PMCID: PMC6814129 DOI: 10.1186/s13041-019-0503-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/01/2019] [Indexed: 12/02/2022] Open
Abstract
Proper axonal branch growth and targeting are essential for establishing a hard-wired neural circuit. Here, we examined the role of Fibroblast Growth Factor Receptors (FGFRs) in axonal arbor development using loss of function and overexpression genetic analyses within single neurons. We used the invariant synaptic connectivity patterns of Drosophila mechanosensory neurons with their innate cleaning reflex responses as readouts for errors in synaptic targeting and circuit function. FGFR loss of function resulted in a decrease in axonal branch number and lengths, and overexpression of FGFRs resulted in ectopic branches and increased lengths. FGFR mutants produced stereotyped axonal targeting errors. Both loss of function and overexpression of FGFRs within the mechanosensory neuron decreased the animal’s frequency of response to mechanosensory stimulation. Our results indicate that FGFRs promote axonal branch growth and proper branch targeting. Disrupting FGFRs results in miswiring and impaired neural circuit function.
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Affiliation(s)
- Júnia Vieira Dos Santos
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Renee Yin Yu
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Andrea Terceros
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Brian Edwin Chen
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada. .,Departments of Medicine, Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada.
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34
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Inter-axonal recognition organizes Drosophila olfactory map formation. Sci Rep 2019; 9:11554. [PMID: 31399611 PMCID: PMC6689066 DOI: 10.1038/s41598-019-47924-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/26/2019] [Indexed: 11/20/2022] Open
Abstract
Olfactory systems across the animal kingdom show astonishing similarities in their morphological and functional organization. In mouse and Drosophila, olfactory sensory neurons are characterized by the selective expression of a single odorant receptor (OR) type and by the OR class-specific connection in the olfactory brain center. Monospecific OR expression in mouse provides each sensory neuron with a unique recognition identity underlying class-specific axon sorting into synaptic glomeruli. Here we show that in Drosophila, although OR genes are not involved in sensory neuron connectivity, afferent sorting via OR class-specific recognition defines a central mechanism of odortopic map formation. Sensory neurons mutant for the Ig-domain receptor Dscam converge into ectopic glomeruli with single OR class identity independent of their target cells. Mosaic analysis showed that Dscam prevents premature recognition among sensory axons of the same OR class. Single Dscam isoform expression in projecting axons revealed the importance of Dscam diversity for spatially restricted glomerular convergence. These data support a model in which the precise temporal-spatial regulation of Dscam activity controls class-specific axon sorting thereby indicating convergent evolution of olfactory map formation via self-patterning of sensory neurons.
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35
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Sachse SM, Lievens S, Ribeiro LF, Dascenco D, Masschaele D, Horré K, Misbaer A, Vanderroost N, De Smet AS, Salta E, Erfurth ML, Kise Y, Nebel S, Van Delm W, Plaisance S, Tavernier J, De Strooper B, De Wit J, Schmucker D. Nuclear import of the DSCAM-cytoplasmic domain drives signaling capable of inhibiting synapse formation. EMBO J 2019; 38:embj.201899669. [PMID: 30745319 DOI: 10.15252/embj.201899669] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 11/09/2022] Open
Abstract
DSCAM and DSCAML1 are immunoglobulin and cell adhesion-type receptors serving important neurodevelopmental functions including control of axon growth, branching, neurite self-avoidance, and neuronal cell death. The signal transduction mechanisms or effectors of DSCAM receptors, however, remain poorly characterized. We used a human ORFeome library to perform a high-throughput screen in mammalian cells and identified novel cytoplasmic signaling effector candidates including the Down syndrome kinase Dyrk1a, STAT3, USP21, and SH2D2A. Unexpectedly, we also found that the intracellular domains (ICDs) of DSCAM and DSCAML1 specifically and directly interact with IPO5, a nuclear import protein of the importin beta family, via a conserved nuclear localization signal. The DSCAM ICD is released by γ-secretase-dependent cleavage, and both the DSCAM and DSCAML1 ICDs efficiently translocate to the nucleus. Furthermore, RNA sequencing confirms that expression of the DSCAM as well as the DSCAML1 ICDs alone can profoundly alter the expression of genes associated with neuronal differentiation and apoptosis, as well as synapse formation and function. Gain-of-function experiments using primary cortical neurons show that increasing the levels of either the DSCAM or the DSCAML1 ICD leads to an impairment of neurite growth. Strikingly, increased expression of either full-length DSCAM or the DSCAM ICD, but not the DSCAML1 ICD, significantly decreases synapse numbers in primary hippocampal neurons. Taken together, we identified a novel membrane-to-nucleus signaling mechanism by which DSCAM receptors can alter the expression of regulators of neuronal differentiation and synapse formation and function. Considering that chromosomal duplications lead to increased DSCAM expression in trisomy 21, our findings may help uncover novel mechanisms contributing to intellectual disability in Down syndrome.
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Affiliation(s)
- Sonja M Sachse
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Sam Lievens
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Luís F Ribeiro
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Dan Dascenco
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Delphine Masschaele
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Katrien Horré
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Anke Misbaer
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Nele Vanderroost
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Anne Sophie De Smet
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Evgenia Salta
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Yoshiaki Kise
- VIB Center for Brain & Disease Research, Leuven, Belgium
| | - Siegfried Nebel
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | | | - Jan Tavernier
- VIB Center for Medical Biotechnology, Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Bart De Strooper
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium.,Dementia Research Institute, University College London, London, UK
| | - Joris De Wit
- VIB Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Dietmar Schmucker
- VIB Center for Brain & Disease Research, Leuven, Belgium .,Department of Neurosciences, KU Leuven, Leuven, Belgium
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36
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Jin Y, Li H. Revisiting Dscam diversity: lessons from clustered protocadherins. Cell Mol Life Sci 2019; 76:667-680. [PMID: 30343321 PMCID: PMC11105660 DOI: 10.1007/s00018-018-2951-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/13/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022]
Abstract
The complexity of neuronal wiring relies on the extraordinary recognition diversity of cell surface molecules. Drosophila Dscam1 and vertebrate clustered protocadherins (Pcdhs) are two classic examples of the striking diversity from a complex genomic locus, wherein the former encodes more than 10,000 distinct isoforms via alternative splicing, while the latter employs alternative promoters to attain isoform diversity. These structurally unrelated families show remarkably striking molecular parallels and even similar functions. Recent studies revealed a novel Dscam gene family with tandemly arrayed 5' cassettes in Chelicerata (e.g., the scorpion Mesobuthus martensii and the tick Ixodes scapularis), similar to vertebrate clustered Pcdhs. Likewise, octopus shows a more remarkable expansion of the Pcdh isoform repertoire than human. These discoveries of Dscam and Pcdh diversification reshape the evolutionary landscape of recognition molecule diversity and provide a greater understanding of convergent molecular strategies for isoform diversity. This article reviews new insights into the evolution, regulatory mechanisms, and functions of Dscam and Pcdh isoform diversity. In particular, the convergence of clustered Dscams and Pcdhs is highlighted.
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Affiliation(s)
- Yongfeng Jin
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, Zhejiang (ZJ), People's Republic of China.
| | - Hao Li
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, Zhejiang (ZJ), People's Republic of China
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37
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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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38
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De novo assembly of a transcriptome for the cricket Gryllus bimaculatus prothoracic ganglion: An invertebrate model for investigating adult central nervous system compensatory plasticity. PLoS One 2018; 13:e0199070. [PMID: 29995882 PMCID: PMC6040699 DOI: 10.1371/journal.pone.0199070] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 05/25/2018] [Indexed: 12/18/2022] Open
Abstract
The auditory system of the cricket, Gryllus bimaculatus, demonstrates an unusual amount of anatomical plasticity in response to injury, even in adults. Unilateral removal of the ear causes deafferented auditory neurons in the prothoracic ganglion to sprout dendrites across the midline, a boundary they typically respect, and become synaptically connected to the auditory afferents of the contralateral ear. The molecular basis of this sprouting and novel synaptogenesis in the adult is not understood. We hypothesize that well-conserved developmental guidance cues may recapitulate their guidance functions in the adult in order to facilitate this compensatory growth. As a first step in testing this hypothesis, we have generated a de novo assembly of a prothoracic ganglion transcriptome derived from control and deafferented adult individuals. We have mined this transcriptome for orthologues of guidance molecules from four well-conserved signaling families: Slit, Netrin, Ephrin, and Semaphorin. Here we report that transcripts encoding putative orthologues of most of the candidate developmental ligands and receptors from these signaling families were present in the assembly, indicating expression in the adult G. bimaculatus prothoracic ganglion.
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39
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Branco AT, Brito RM, Lemos B. Sex-specific adaptation and genomic responses to Y chromosome presence in female reproductive and neural tissues. Proc Biol Sci 2018; 284:rspb.2017.2062. [PMID: 29237855 DOI: 10.1098/rspb.2017.2062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/06/2017] [Indexed: 12/21/2022] Open
Abstract
Y chromosomes typically harbour a small number of genes and an abundance of repetitive sequences. In Drosophila, the Y chromosome comprises multimegabase long segments of repetitive DNA and a handful of protein-coding genes. In mammals, the Y chromosome also harbours a disproportionally high abundance of repeats. Here, we built on a Drosophila melanogaster model in which the Y chromosome is decoupled from sexual determination. Genotypes were genetically identical for the autosomes, X chromosome, and mitochondria, but differ by the presence or dose of the Y chromosome. Addition of an extra Y chromosome had limited impact in males. However, the presence of a Y chromosome in females induced a disproportionate response in genes expressed in the ovaries as well as genes encoded by the mitochondrial genome. Furthermore, the data revealed significant consequences of Y chromosome presence in larvae neuronal tissue. This included the repression of genes implicated in reproductive behaviour, courtship, mating and synaptic function. Our findings exhibit the Y chromosome as a hotspot for sex-specific adaptation. They suggest roles for natural selection on Y-linked genetic elements exerting impact on sex-specific tissues as well as somatic tissues shared by males and females.
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Affiliation(s)
- Alan T Branco
- Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard T. H. Chan School of Public Health, 665 Huntington Avenue, 02115, Boston, MA, USA
| | - Rute M Brito
- Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard T. H. Chan School of Public Health, 665 Huntington Avenue, 02115, Boston, MA, USA
| | - Bernardo Lemos
- Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard T. H. Chan School of Public Health, 665 Huntington Avenue, 02115, Boston, MA, USA
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40
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Jin Y, Dong H, Shi Y, Bian L. Mutually exclusive alternative splicing of pre-mRNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1468. [PMID: 29423937 DOI: 10.1002/wrna.1468] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/20/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
Pre-mRNA alternative splicing is an important mechanism used to expand protein diversity in higher eukaryotes, and mutually exclusive splicing is a specific type of alternative splicing in which only one of the exons in a cluster is included in functional transcripts. The most extraordinary example of this is the Drosophila melanogaster Down's syndrome cell adhesion molecule gene (Dscam), which potentially encodes 38,016 different isoforms through mutually exclusive splicing. Mutually exclusive splicing is a unique and challenging model that can be used to elucidate the evolution, regulatory mechanism, and function of alternative splicing. The use of new approaches has not only greatly expanded the mutually exclusive exome, but has also enabled the systematic analyses of single-cell alternative splicing during development. Furthermore, the identification of long-range RNA secondary structures provides a mechanistic framework for the regulation of mutually exclusive splicing (i.e., Dscam splicing). This article reviews recent insights into the identification, underlying mechanism, and roles of mutually exclusive splicing. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Yongfeng Jin
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Haiyang Dong
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Yang Shi
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Lina Bian
- Institute of Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
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41
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A chelicerate-specific burst of nonclassical Dscam diversity. BMC Genomics 2018; 19:66. [PMID: 29351731 PMCID: PMC5775551 DOI: 10.1186/s12864-017-4420-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 12/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The immunoglobulin (Ig) superfamily receptor Down syndrome cell adhesion molecule (Dscam) gene can generate tens of thousands of isoforms via alternative splicing, which is essential for both nervous and immune systems in insects. However, further information is required to develop a comprehensive view of Dscam diversification across the broad spectrum of Chelicerata clades, a basal branch of arthropods and the second largest group of terrestrial animals. RESULTS In this study, a genome-wide comprehensive analysis of Dscam genes across Chelicerata species revealed a burst of nonclassical Dscams, categorised into four types-mDscam, sDscamα, sDscamβ, and sDscamγ-based on their size and structure. Although the mDscam gene class includes the highest number of Dscam genes, the sDscam genes utilise alternative promoters to expand protein diversity. Furthermore, we indicated that the 5' cassette duplicate is inversely correlated with the sDscam gene duplicate. We showed differential and sDscam- biased expression of nonclassical Dscam isoforms. Thus, the Dscam isoform repertoire across Chelicerata is entirely dominated by the number and expression levels of nonclassical Dscams. Taken together, these data show that Chelicerata evolved a large conserved and lineage-specific repertoire of nonclassical Dscams. CONCLUSIONS This study showed that arthropods have a large diversified Chelicerata-specific repertoire of nonclassical Dscam isoforms, which are structurally and mechanistically distinct from those of insects. These findings provide a global framework for the evolution of Dscam diversity in arthropods and offer mechanistic insights into the diversification of the clade-specific Ig superfamily repertoire.
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42
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Salazar JL, Yamamoto S. Integration of Drosophila and Human Genetics to Understand Notch Signaling Related Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1066:141-185. [PMID: 30030826 PMCID: PMC6233323 DOI: 10.1007/978-3-319-89512-3_8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Notch signaling research dates back to more than one hundred years, beginning with the identification of the Notch mutant in the fruit fly Drosophila melanogaster. Since then, research on Notch and related genes in flies has laid the foundation of what we now know as the Notch signaling pathway. In the 1990s, basic biological and biochemical studies of Notch signaling components in mammalian systems, as well as identification of rare mutations in Notch signaling pathway genes in human patients with rare Mendelian diseases or cancer, increased the significance of this pathway in human biology and medicine. In the 21st century, Drosophila and other genetic model organisms continue to play a leading role in understanding basic Notch biology. Furthermore, these model organisms can be used in a translational manner to study underlying mechanisms of Notch-related human diseases and to investigate the function of novel disease associated genes and variants. In this chapter, we first briefly review the major contributions of Drosophila to Notch signaling research, discussing the similarities and differences between the fly and human pathways. Next, we introduce several biological contexts in Drosophila in which Notch signaling has been extensively characterized. Finally, we discuss a number of genetic diseases caused by mutations in genes in the Notch signaling pathway in humans and we expand on how Drosophila can be used to study rare genetic variants associated with these and novel disorders. By combining modern genomics and state-of-the art technologies, Drosophila research is continuing to reveal exciting biology that sheds light onto mechanisms of disease.
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Affiliation(s)
- Jose L Salazar
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA.
- Program in Developmental Biology, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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43
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Li W, Tang X, Chen Y, Sun W, Liu Y, Gong Y, Wen X, Li S. Characterize a typically Dscam with alternative splicing in mud crab Scylla paramamosain. FISH & SHELLFISH IMMUNOLOGY 2017; 71:305-318. [PMID: 29042325 DOI: 10.1016/j.fsi.2017.10.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 10/08/2017] [Accepted: 10/13/2017] [Indexed: 06/07/2023]
Abstract
As a member of the immunoglobulin superfamily, Down syndrome cell adhesion molecule (Dscam) could function in the innate immunity of invertebrates. Recently, it is shown that arthropod Dscams play similar functions as antibodies in the adaptive immune system. Dscam could produce thousands of isoforms by alternative splicing and specifically bind to various pathogens. In the present study, we cloned the first Dscam from mud crab Scylla paramamosain (SpDscam), with full-length cDNA 7363 bp containing an open reading frame (ORF) of 6069bp and encoding 2022 amino acids, which had typical domain architecture as other arthropods, i.e., 10 immunoglobulin domains (Ig), 6 fibronectin type 3 domains (FN III), transmembrane and cytoplasmic tail. Quantitative real-time PCR revealed that SpDscam was highly expressed in brain, skin, muscle, intestine and hepatopancreas, but weakly expressed in hemolymph, heart and gill. SpDscam had three alternative splicing regions, located at the N-terminal of Ig2 and Ig3 as well as on the whole Ig7. In these regions, 32, 41 and 14 exons were detected, together with the two exon types of transmembrane domain, indicating SpDscam could potentially encode at least 36,736 unique isoforms. SpDscam induced by Vibrio parahaemolyticus challenge had strong binding ability to V. parahaemolyticus. Further, SpDscam induced by V. parahaemolyticus possessed a clearance of V. parahaemolyticus in S. paramamosain. Collectively, the results indicated SpDscam was a hypervariable pattern-recognition receptor (PRR) by alternative splicing in innate immunity system of mud crab S. paramamosain.
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Affiliation(s)
- Wenshi Li
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China
| | - Xixiang Tang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China
| | - Yan Chen
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China
| | - Wanwei Sun
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China
| | - Yan Liu
- Department of Biology, Shantou University, Shantou 515063, China
| | - Yi Gong
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China
| | - Xiaobo Wen
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China
| | - Shengkang Li
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou 515063, China; Marine Biology Institute, Shantou University, Shantou 515063, China.
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44
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Simmons AB, Bloomsburg SJ, Sukeena JM, Miller CJ, Ortega-Burgos Y, Borghuis BG, Fuerst PG. DSCAM-mediated control of dendritic and axonal arbor outgrowth enforces tiling and inhibits synaptic plasticity. Proc Natl Acad Sci U S A 2017; 114:E10224-E10233. [PMID: 29114051 PMCID: PMC5703318 DOI: 10.1073/pnas.1713548114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mature mammalian neurons have a limited ability to extend neurites and make new synaptic connections, but the mechanisms that inhibit such plasticity remain poorly understood. Here, we report that OFF-type retinal bipolar cells in mice are an exception to this rule, as they form new anatomical connections within their tiled dendritic fields well after retinal maturity. The Down syndrome cell-adhesion molecule (Dscam) confines these anatomical rearrangements within the normal tiled fields, as conditional deletion of the gene permits extension of dendrite and axon arbors beyond these borders. Dscam deletion in the mature retina results in expanded dendritic fields and increased cone photoreceptor contacts, demonstrating that DSCAM actively inhibits circuit-level plasticity. Electrophysiological recordings from Dscam-/- OFF bipolar cells showed enlarged visual receptive fields, demonstrating that expanded dendritic territories comprise functional synapses. Our results identify cell-adhesion molecule-mediated inhibition as a regulator of circuit-level neuronal plasticity in the adult retina.
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Affiliation(s)
- Aaron B Simmons
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844
| | | | - Joshua M Sukeena
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844
| | - Calvin J Miller
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844
| | - Yohaniz Ortega-Burgos
- Department of Chemistry, University of Puerto Rico-Humacao, Humacao Puerto Rico, 00792
| | - Bart G Borghuis
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40202;
| | - Peter G Fuerst
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844;
- Washington-Wyoming-Alaska-Montana-Idaho Medical Education Program, University of Washington School of Medicine, Moscow, ID 83844
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45
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Jia YL, Fu ZX, Zhang BH, Jia YJ. Hippocampal overexpression of Down syndrome cell adhesion molecule in amyloid precursor protein transgenic mice. ACTA ACUST UNITED AC 2017; 50:e6049. [PMID: 28513774 PMCID: PMC5479388 DOI: 10.1590/1414-431x20176049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 03/20/2017] [Indexed: 11/25/2022]
Abstract
Down syndrome cell adhesion molecule (DSCAM) is located within the Down syndrome critical region of chromosome 21. DSCAM is a broadly expressed neurodevelopmental protein involved in synaptogenesis, neurite outgrowth, and axon guidance. We previously demonstrated DSCAM overexpression in the cortex of amyloid precursor protein (APP) transgenic mice, suggesting possible regulatory interactions between APP and DSCAM. APP mice exhibit deficits in hippocampus-dependent learning and memory. In this preliminary study, we examined age-related changes in DSCAM expression within the hippocampus in 16 APP transgenic mice (1, 3, 6 and 12 months old). Hippocampus-dependent spatial memory was assessed in APP mice and age-matched wild type littermates (WTs) using the Morris water maze (MWM). The cellular distribution of hippocampal DSCAM and total expression at both mRNA and protein levels were measured by immunohistochemistry, qRT-PCR, and western blotting, respectively. APP mice exhibited spatial memory deficits in the MWM. Intense DSCAM immunoreactivity was observed in the dentate gyrus granule cell layer and hippocampal stratum pyramidale. Total hippocampal DSCAM mRNA and protein expression levels were substantially higher in APP mice than WTs at 1 and 3 months of age. Expression decreased with age in both groups but remained higher in APP mice. DSCAM is overexpressed in the hippocampus over the first 12 months of life in APP mice, but especially during maturation to adulthood. In conclusion, these results suggest an association between DSCAM and APP mice, which is characterized by neuropathology and behavioral deficits. These results provide some clues for future studies on the role of DSCAM overexpression in the precocious cognitive decline observed in APP transgenic mice.
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Affiliation(s)
- Y L Jia
- Department of Neurology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan Province, China.,Department of Neurology, The Central Hospital of Kaifeng, Kaifeng, Henan Province, China
| | - Z X Fu
- Department of Neurology, The Central Hospital of Kaifeng, Kaifeng, Henan Province, China
| | - B H Zhang
- Department of Neurology, The Central Hospital of Kaifeng, Kaifeng, Henan Province, China
| | - Y J Jia
- Department of Neurology, the First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan Province, China
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46
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DSCAM promotes axon fasciculation and growth in the developing optic pathway. Proc Natl Acad Sci U S A 2017; 114:1702-1707. [PMID: 28137836 DOI: 10.1073/pnas.1618606114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although many aspects of optic pathway development are beginning to be understood, the mechanisms promoting the growth of retinal ganglion cell (RGC) axons toward visual targets remain largely unknown. Down syndrome cell adhesion molecule (Dscam) is expressed by mouse RGCs shortly after they differentiate at embryonic day 12 and is essential for multiple aspects of postnatal visual system development. Here we show that Dscam is also required during embryonic development for the fasciculation and growth of RGC axons. Dscam is expressed along the developing optic pathway in a pattern consistent with a role in regulating RGC axon outgrowth. In mice carrying spontaneous mutations in Dscam (Dscamdel17 ; Dscam2J), RGC axons pathfind normally, but growth from the chiasm toward their targets is impaired, resulting in a delay in RGC axons reaching the dorsal thalamus compared with that seen in wild-type littermates. Conversely, Dscam gain of function results in exuberant growth into the dorsal thalamus. The growth of ipsilaterally projecting axons is particularly affected. Axon organization in the optic chiasm and tract and RGC growth cone morphologies are also altered in Dscam mutants. In vitro DSCAM promotes RGC axon growth and fasciculation, and can act independently of cell contact. In vitro and in situ DSCAM is required both in the RGC axons and in their environment for the promotion of axon outgrowth, consistent with a homotypic mode of action. These findings identify DSCAM as a permissive signal that promotes the growth and fasciculation of RGC axons, controlling the timing of when RGC axons reach their targets.
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47
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Oliva C, Hassan BA. Receptor Tyrosine Kinases and Phosphatases in Neuronal Wiring: Insights From Drosophila. Curr Top Dev Biol 2016; 123:399-432. [PMID: 28236973 DOI: 10.1016/bs.ctdb.2016.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Tyrosine phosphorylation is at the crossroads of many signaling pathways. Brain wiring is not an exception, and several receptor tyrosine kinases (RTKs) and tyrosine receptor phosphates (RPTPs) have been involved in this process. Considerable work has been done on RTKs, and for many of them, detailed molecular mechanisms and functions in several systems have been characterized. In contrast, RPTPs have been studied considerably less and little is known about their ligands and substrates. In both families, we find redundancy between different members to accomplish particular wiring patterns. Strikingly, some RTKs and RPTPs have lost their catalytic activity during evolution, but not their importance in biological processes. In this regard, we have to keep in mind that these proteins have multiple domains and some of their functions are independent of tyrosine phosphorylation/dephosphorylation. Since RTKs and RPTPs are enzymes involved not only in early stages of axon and dendrite pathfinding but also in synapse formation and physiology, they have a potential as drug targets. Drosophila has been a key model organism in the search of a better understanding of brain wiring, and its sophisticated toolbox is very suitable for studying the function of genes with pleiotropic functions such as RTKs and RPTPs, from wiring to synaptic formation and function. In these review, we mainly cover findings from this model organism and complement them with discoveries in vertebrate systems.
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Affiliation(s)
- Carlos Oliva
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad of Chile, Santiago, Chile.
| | - Bassem A Hassan
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Institut du Cerveau et la Moelle (ICM)-Hôpital Pitié-Salpêtrière, Boulevard de l'Hôpital, Paris, France.
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48
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Affiliation(s)
- Larry W. Swanson
- Department of Biological Sciences, University of Southern California, Los Angeles, California 90089;
| | - Jeff W. Lichtman
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138;
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49
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Li SA, Cheng L, Yu Y, Wang JH, Chen Q. Structural basis of Dscam1 homodimerization: Insights into context constraint for protein recognition. SCIENCE ADVANCES 2016; 2:e1501118. [PMID: 27386517 PMCID: PMC4928987 DOI: 10.1126/sciadv.1501118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 04/29/2016] [Indexed: 02/05/2023]
Abstract
The Drosophila neural receptor Dscam1 (Down syndrome cell adhesion molecule 1) plays an essential role in neuronal wiring and self-avoidance. Dscam1 potentially encodes 19,008 ectodomains through alternative RNA splicing and exhibits exquisite isoform-specific homophilic binding, which makes it an exceptional example for studying protein binding specificity. However, structural information on Dscam1 is limited, which hinders illumination of the mechanism of Dscam1 isoform-specific recognition. Whether different Dscam1 isoforms adopt the same dimerization mode remains a subject of debate. We present 12 Dscam1 crystal structures, provide direct evidence indicating that all isoforms adopt a conserved homodimer geometry in a modular fashion, identify two mechanisms for the Ig2 binding domain to dispel electrostatic repulsion during dimerization, decode Ig2 binding specificity by a central motif at its symmetry center, uncover the role of glycosylation in Dscam1 homodimerization, and find electrostatic potential complementarity to help define the binding region and the antiparallel binding mode. We then propose a concept that the context of a protein may set restrictions to regulate its binding specificity, which provides a better understanding of protein recognition.
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Affiliation(s)
- Shu-Ang Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P. R. China
| | - Linna Cheng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P. R. China
| | - Yamei Yu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P. R. China
| | - Jia-Huai Wang
- Departments of Medical Oncology and Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA. Department of Pediatrics and Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Qiang Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu 610041, P. R. China
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50
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Yue Y, Meng Y, Ma H, Hou S, Cao G, Hong W, Shi Y, Guo P, Liu B, Shi F, Yang Y, Jin Y. A large family of Dscam genes with tandemly arrayed 5' cassettes in Chelicerata. Nat Commun 2016; 7:11252. [PMID: 27080167 PMCID: PMC4835542 DOI: 10.1038/ncomms11252] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/07/2016] [Indexed: 02/04/2023] Open
Abstract
Drosophila Dscam1 (Down Syndrome Cell Adhesion Molecules) and vertebrate clustered protocadherins (Pcdhs) are two classic examples of the extraordinary isoform diversity from a single genomic locus. Dscam1 encodes 38,016 distinct isoforms via mutually exclusive splicing in D. melanogaster, while the vertebrate clustered Pcdhs utilize alternative promoters to generate isoform diversity. Here we reveal a shortened Dscam gene family with tandemly arrayed 5' cassettes in Chelicerata. These cassette repeats generally comprise two or four exons, corresponding to variable Immunoglobulin 7 (Ig7) or Ig7-8 domains of Drosophila Dscam1. Furthermore, extraordinary isoform diversity has been generated through a combination of alternating promoter and alternative splicing. These sDscams have a high sequence similarity with Drosophila Dscam1, and share striking organizational resemblance to the 5' variable regions of vertebrate clustered Pcdhs. Hence, our findings have important implications for understanding the functional similarities between Drosophila Dscam1 and vertebrate Pcdhs, and may provide further mechanistic insights into the regulation of isoform diversity.
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Affiliation(s)
- Yuan Yue
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yijun Meng
- College of Life and Environmental Sciences; Hangzhou Normal University, Hangzhou, Zhejiang ZJ310036, China
| | - Hongru Ma
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Shouqing Hou
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Guozheng Cao
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Weiling Hong
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yang Shi
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Pengjuan Guo
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Baoping Liu
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Feng Shi
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yun Yang
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
| | - Yongfeng Jin
- Institute of Biochemistry, Innovation Center for Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, China
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