1
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Xia HH, Zhu LM, Shen LT, Wan ZC. Cytoplasmic tail of transmembrane dscam controls antibacterial responses by regulating cell proliferation-related genes in hemocytes of Chinese mitten crab (Eriocheir sinensis). FISH & SHELLFISH IMMUNOLOGY 2024; 151:109626. [PMID: 38797334 DOI: 10.1016/j.fsi.2024.109626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/07/2024] [Accepted: 05/11/2024] [Indexed: 05/29/2024]
Abstract
In arthropods, the involvement of Dscam (Down syndrome cell adhesion molecule) in innate immunity has been extensively demonstrated. Its cytoplasmic tail contains multiple conserved functional sites, which indicates its involvement in different intracellular signaling pathways. In this study, we focused on the role of the cytoplasmic tail of Dscam in the Chinese mitten crab (Eriocheir sinensis) immune defense. In the group with cytoplasmic tail knockdown (the site was located on constant exons 37 and 38), 3885 differentially expressed genes (DEGs) were identified. The DEGs were enriched in small molecule binding, protein-containing complex binding, and immunity-related pathways. The expression of selected genes were validated using quantitative real-time reverse transcription PCR. We identified key Cell cycle, Janus kinase (JAK)-signal transducer, activator of transcription (STAT) and mitogen-activated protein kinase (MAPK) signaling pathway genes, the results indicated that the cytoplasmic tail of Dscam controls antibacterial responses by regulating cell proliferation-related genes in hemocytes.
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Affiliation(s)
- Hong-Hao Xia
- College of Animal Science and Technology, Anhui Agricultural University, Hefei City, Anhui Province, 230031, PR China
| | - Le-Mei Zhu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei City, Anhui Province, 230031, PR China
| | - Long-Teng Shen
- College of Animal Science and Technology, Anhui Agricultural University, Hefei City, Anhui Province, 230031, PR China
| | - Zhi-Cheng Wan
- College of Animal Science and Technology, Anhui Agricultural University, Hefei City, Anhui Province, 230031, PR China.
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2
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Lu X, Ni P, Suarez-Meade P, Ma Y, Forrest EN, Wang G, Wang Y, Quiñones-Hinojosa A, Gerstein M, Jiang YH. Transcriptional determinism and stochasticity contribute to the complexity of autism-associated SHANK family genes. Cell Rep 2024; 43:114376. [PMID: 38900637 DOI: 10.1016/j.celrep.2024.114376] [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: 01/09/2024] [Revised: 05/08/2024] [Accepted: 05/31/2024] [Indexed: 06/22/2024] Open
Abstract
Precision of transcription is critical because transcriptional dysregulation is disease causing. Traditional methods of transcriptional profiling are inadequate to elucidate the full spectrum of the transcriptome, particularly for longer and less abundant mRNAs. SHANK3 is one of the most common autism causative genes. Twenty-four Shank3-mutant animal lines have been developed for autism modeling. However, their preclinical validity has been questioned due to incomplete Shank3 transcript structure. We apply an integrative approach combining cDNA-capture and long-read sequencing to profile the SHANK3 transcriptome in humans and mice. We unexpectedly discover an extremely complex SHANK3 transcriptome. Specific SHANK3 transcripts are altered in Shank3-mutant mice and postmortem brain tissues from individuals with autism spectrum disorder. The enhanced SHANK3 transcriptome significantly improves the detection rate for potential deleterious variants from genomics studies of neuropsychiatric disorders. Our findings suggest that both deterministic and stochastic transcription of the genome is associated with SHANK family genes.
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Affiliation(s)
- Xiaona Lu
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Pengyu Ni
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | - Yu Ma
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 201102, China
| | - Emily Niemitz Forrest
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Guilin Wang
- Keck Microarray Shared Resource, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, Shanghai 201102, China
| | | | - Mark Gerstein
- Program in Computational Biology and Bioinformatics, Yale University, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Computer Science, Yale University, New Haven, CT 06520, USA; Department of Statistics and Data Science, Yale University, New Haven, CT 06520, USA; Department of Biomedical Informatics & Data Science, Yale University, New Haven, CT 06520, USA
| | - Yong-Hui Jiang
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA; Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA; Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA.
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3
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Hizawa K, Sasaki T, Arimura N. A comparative overview of DSCAM and its multifunctional roles in Drosophila and vertebrates. Neurosci Res 2024; 202:1-7. [PMID: 38141781 DOI: 10.1016/j.neures.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/21/2023] [Accepted: 12/14/2023] [Indexed: 12/25/2023]
Abstract
DSCAM (Down syndrome cell adhesion molecule) is a unique neuronal adhesion protein with extensively documented multifaceted functionalities. DSCAM also has interesting properties in vertebrates and invertebrates, respectively. In Drosophila species, particularly, Dscam exhibits remarkable genetic diversity, with tens of thousands of splicing isoforms that modulate the specificity of neuronal wiring. Interestingly, this splice variant diversity of Dscam is absent in vertebrates. DSCAM plays a pivotal role in mitigating excessive adhesion between identical cell types, thereby maintaining the structural and functional coherence of neural networks. DSCAM contributes to the oversight of selective intercellular interactions such as synaptogenesis; however, the precise regulatory mechanisms underlying the promotion and inhibition of cell adhesion involved remain unclear. In this review, we aim to delineate the distinct molecules that interact with DSCAM and their specific roles within the biological landscapes of Drosophila and vertebrates. By integrating these comparative insights, we aim to elucidate the multifunctional nature of DSCAM, particularly its capacity to facilitate or deter intercellular adhesion.
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Affiliation(s)
- Kento Hizawa
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8578, Japan
| | - Takuya Sasaki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8578, Japan
| | - Nariko Arimura
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba Ward, Sendai, Miyagi 980-8578, Japan.
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4
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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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5
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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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6
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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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7
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Liu H, Caballero-Florán RN, Hergenreder T, Yang T, Hull JM, Pan G, Li R, Veling MW, Isom LL, Kwan KY, Huang ZJ, Fuerst PG, Jenkins PM, Ye B. DSCAM gene triplication causes excessive GABAergic synapses in the neocortex in Down syndrome mouse models. PLoS Biol 2023; 21:e3002078. [PMID: 37079499 PMCID: PMC10118173 DOI: 10.1371/journal.pbio.3002078] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/14/2023] [Indexed: 04/21/2023] Open
Abstract
Down syndrome (DS) is caused by the trisomy of human chromosome 21 (HSA21). A major challenge in DS research is to identify the HSA21 genes that cause specific symptoms. Down syndrome cell adhesion molecule (DSCAM) is encoded by a HSA21 gene. Previous studies have shown that the protein level of the Drosophila homolog of DSCAM determines the size of presynaptic terminals. However, whether the triplication of DSCAM contributes to presynaptic development in DS remains unknown. Here, we show that DSCAM levels regulate GABAergic synapses formed on neocortical pyramidal neurons (PyNs). In the Ts65Dn mouse model for DS, where DSCAM is overexpressed due to DSCAM triplication, GABAergic innervation of PyNs by basket and chandelier interneurons is increased. Genetic normalization of DSCAM expression rescues the excessive GABAergic innervations and the increased inhibition of PyNs. Conversely, loss of DSCAM impairs GABAergic synapse development and function. These findings demonstrate excessive GABAergic innervation and synaptic transmission in the neocortex of DS mouse models and identify DSCAM overexpression as the cause. They also implicate dysregulated DSCAM levels as a potential pathogenic driver in related neurological disorders.
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Affiliation(s)
- Hao Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - René N. Caballero-Florán
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Ty Hergenreder
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Tao Yang
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jacob M. Hull
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Geng Pan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Ruonan Li
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Macy W. Veling
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Kenneth Y. Kwan
- Michigan Neuroscience Institute, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Z. Josh Huang
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biomedical Engineering, Duke University Pratt School of Engineering, Durham, North Carolina, United States of America
| | - Peter G. Fuerst
- University of Idaho, Department of Biological Sciences, Moscow, Idaho, United States of America
| | - Paul M. Jenkins
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Bing Ye
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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8
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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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9
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Cortés E, Pak JS, Özkan E. Structure and evolution of neuronal wiring receptors and ligands. Dev Dyn 2023; 252:27-60. [PMID: 35727136 PMCID: PMC10084454 DOI: 10.1002/dvdy.512] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 01/04/2023] Open
Abstract
One of the fundamental properties of a neuronal circuit is the map of its connections. The cellular and developmental processes that allow for the growth of axons and dendrites, selection of synaptic targets, and formation of functional synapses use neuronal surface receptors and their interactions with other surface receptors, secreted ligands, and matrix molecules. Spatiotemporal regulation of the expression of these receptors and cues allows for specificity in the developmental pathways that wire stereotyped circuits. The families of molecules controlling axon guidance and synapse formation are generally conserved across animals, with some important exceptions, which have consequences for neuronal connectivity. Here, we summarize the distribution of such molecules across multiple taxa, with a focus on model organisms, evolutionary processes that led to the multitude of such molecules, and functional consequences for the diversification or loss of these receptors.
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Affiliation(s)
- Elena Cortés
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Joseph S Pak
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
| | - Engin Özkan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA.,The Neuroscience Institute, University of Chicago, Chicago, Illinois, USA
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10
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Dscam1: Is It a Ubiquitous Code for Dendritic Arborization? eNeuro 2023; 10:10/1/ENEURO.0440-22.2023. [PMID: 36702556 PMCID: PMC9884107 DOI: 10.1523/eneuro.0440-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/28/2023] Open
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11
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Hou S, Li G, Xu B, Dong H, Zhang S, Fu Y, Shi J, Li L, Fu J, Shi F, Meng Y, Jin Y. Trans-splicing facilitated by RNA pairing greatly expands sDscam isoform diversity but not homophilic binding specificity. SCIENCE ADVANCES 2022; 8:eabn9458. [PMID: 35857463 PMCID: PMC9258826 DOI: 10.1126/sciadv.abn9458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
The Down syndrome cell adhesion molecule 1 (Dscam1) gene can generate tens of thousands of isoforms via alternative splicing, which is essential for nervous and immune functions. Chelicerates generate approximately 50 to 100 shortened Dscam (sDscam) isoforms by alternative promoters, similar to mammalian protocadherins. Here, we reveal that trans-splicing markedly increases the repository of sDscamβ isoforms in Tetranychus urticae. Unexpectedly, every variable exon cassette engages in trans-splicing with constant exons from another cluster. Moreover, we provide evidence that competing RNA pairing not only governs alternative cis-splicing but also facilitates trans-splicing. Trans-spliced sDscam isoforms mediate cell adhesion ability but exhibit the same homophilic binding specificity as their cis-spliced counterparts. Thus, we reveal a single sDscam locus that generates diverse adhesion molecules through cis- and trans-splicing coupled with alternative promoters. These findings expand understanding of the mechanism underlying molecular diversity and have implications for the molecular control of neuronal and/or immune specificity.
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Affiliation(s)
- Shouqing Hou
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Guo Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Bingbing Xu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Haiyang Dong
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Shixin Zhang
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Ying Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jilong Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Lei Li
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Jiayan Fu
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Feng Shi
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
| | - Yijun Meng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, Zhejiang ZJ310018, P. R. China
| | - Yongfeng Jin
- MOE Laboratory of Biosystems Homeostasis and Protection and Innovation Center for Cell Signaling Network, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang ZJ310058, P. R. China
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12
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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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13
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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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14
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Lemieux M, Thiry L, Laflamme OD, Bretzner F. Role of DSCAM in the Development of Neural Control of Movement and Locomotion. Int J Mol Sci 2021; 22:ijms22168511. [PMID: 34445216 PMCID: PMC8395195 DOI: 10.3390/ijms22168511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 11/30/2022] Open
Abstract
Locomotion results in an alternance of flexor and extensor muscles between left and right limbs generated by motoneurons that are controlled by the spinal interneuronal circuit. This spinal locomotor circuit is modulated by sensory afferents, which relay proprioceptive and cutaneous inputs that inform the spatial position of limbs in space and potential contacts with our environment respectively, but also by supraspinal descending commands of the brain that allow us to navigate in complex environments, avoid obstacles, chase prey, or flee predators. Although signaling pathways are important in the establishment and maintenance of motor circuits, the role of DSCAM, a cell adherence molecule associated with Down syndrome, has only recently been investigated in the context of motor control and locomotion in the rodent. DSCAM is known to be involved in lamination and delamination, synaptic targeting, axonal guidance, dendritic and cell tiling, axonal fasciculation and branching, programmed cell death, and synaptogenesis, all of which can impact the establishment of motor circuits during development, but also their maintenance through adulthood. We discuss herein how DSCAM is important for proper motor coordination, especially for breathing and locomotion.
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Affiliation(s)
- Maxime Lemieux
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Louise Thiry
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Olivier D. Laflamme
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
| | - Frédéric Bretzner
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, CHUL-Neurosciences P09800, 2705 boul. Laurier, Québec, QC G1V 4G2, Canada; (M.L.); (L.T.); (O.D.L.)
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Université Laval, Québec, QC G1V 4G2, Canada
- Correspondence:
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15
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Lu YJ, Yu WW, Cui MM, Yu XX, Song HL, Bai MR, Wu WJ, Gu BL, Wang J, Cai W, Chu X. Association Analysis of Variants of DSCAM and BACE2 With Hirschsprung Disease Susceptibility in Han Chinese and Functional Evaluation in Zebrafish. Front Cell Dev Biol 2021; 9:641152. [PMID: 34136475 PMCID: PMC8201997 DOI: 10.3389/fcell.2021.641152] [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: 12/13/2020] [Accepted: 04/20/2021] [Indexed: 11/17/2022] Open
Abstract
Hirschsprung disease (HSCR) has a higher incidence in children with Down syndrome (DS), which makes trisomy 21 a predisposing factor to HSCR. DSCAM and BACE2 are close together on the HSCR-associated critical region of chromosome 21. Common variants of DSCAM and rare variants of BACE2 were implicated to be associated with sporadic HSCR. However, the submucosal neuron defect of DS mouse model could not be rescued by normalization of Dscam. We aimed to explore the contribution of DSCAM and BACE2 to the development of the enteric nervous system (ENS) and HSCR susceptibility. We genotyped 133 tag single-nucleotide polymorphisms (SNPs) in DSCAM and BACE2 gene region in 420 HSCR patients and 1,665 controls of Han Chinese. Expression of DSCAM and BACE2 homologs was investigated in the developing gut of zebrafish. Overexpression and knockdown of the homologs were performed in zebrafish to investigate their roles in the development of ENS. Two DSCAM SNPs, rs430255 (PAddtive = 0.0052, OR = 1.36, 95% CI: 1.10–1.68) and rs2837756 (PAddtive = 0.0091, OR = 1.23, 95% CI: 1.05–1.43), showed suggestive association with HSCR risk. Common variants in BACE2 were not associated with HSCR risk. We observed dscama, dscamb, and bace2 expression in the developing gut of zebrafish. Knockdown of dscama, dscamb, and bace2 caused a reduction of enteric neurons in the hindgut of zebrafish. Overexpression of DSCAM and bace2 had no effects on neuron number in the hindgut of zebrafish. Our results suggested that common variation of DSCAM contributed to HSCR risk in Han Chinese. The dysfunction of both dscams and bace2 caused defects in enteric neuron, indicating that DSCAM and BACE2 might play functional roles in the occurrence of HSCR. These novel findings might shed new light on the pathogenesis of HSCR.
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Affiliation(s)
- Yan-Jiao Lu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Wen-Wen Yu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Meng-Meng Cui
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Xian-Xian Yu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Huan-Lei Song
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Mei-Rong Bai
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Wen-Jie Wu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Bei-Lin Gu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Jun Wang
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Wei Cai
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Xun Chu
- Department of Pediatric Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
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16
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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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17
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Hildebrandt C, Fulton A, Rodan LH. Homozygous deletion of 21q22.2 in a patient with hypotonia, developmental delay, cortical visual impairment, and retinopathy. Am J Med Genet A 2020; 185:555-560. [PMID: 33170561 DOI: 10.1002/ajmg.a.61969] [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: 05/28/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 11/09/2022]
Abstract
21q22 contains several dosage sensitive genes that are important in neurocognitive development. Determining impacts of gene dosage alterations in this region can be useful in establishing contributions of these genes to human development and disease. We describe a 15-month-old girl with a 1,140 kb homozygous deletion in the Down Syndrome Critical Region at 21q22.2 including 4 genes; B3GALT5, IGSF5, PCP4, DSCAM, and a microRNA (MIR4760). Clinical singleton genome sequencing did not report any candidate gene variants for the patient's phenotype. She presented with hypotonia, global developmental delay, cortical visual impairment, and mild facial dysmorphism. Ophthalmological exam was suggestive of retinopathy. We propose that the absence of DSCAM and PCP4 may contribute to the patient's neurological and retinal phenotype, while the role of absent B3GALT5 and IGSF5 in her presentation remain unclear at this time.
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Affiliation(s)
- Clara Hildebrandt
- Medical Biochemical Fellowship at Boston Children's Hospital, Boston, Massachusetts, USA
| | - Anne Fulton
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Lance H Rodan
- Department of Genetics and Genomics, Boston Children's Hospital, Boston, Massachusetts, USA
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18
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Moyer AJ, Gardiner K, Reeves RH. All Creatures Great and Small: New Approaches for Understanding Down Syndrome Genetics. Trends Genet 2020; 37:444-459. [PMID: 33097276 DOI: 10.1016/j.tig.2020.09.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/17/2020] [Accepted: 09/22/2020] [Indexed: 12/26/2022]
Abstract
Human chromosome 21 (Hsa21) contains more than 500 genes, making trisomy 21 one of the most complex genetic perturbations compatible with life. The ultimate goal of Down syndrome (DS) research is to design therapies that improve quality of life for individuals with DS by understanding which subsets of Hsa21 genes contribute to DS-associated phenotypes throughout the lifetime. However, the complexity of DS pathogenesis has made developing appropriate animal models an ongoing challenge. Here, we examine lessons learned from a variety of model systems, including yeast, nematode, fruit fly, and zebrafish, and discuss emerging methods for creating murine models that better reflect the genetic basis of trisomy 21.
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Affiliation(s)
- Anna J Moyer
- Department of Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Katheleen Gardiner
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA (retired)
| | - Roger H Reeves
- Department of Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
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19
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Chelicerata sDscam isoforms combine homophilic specificities to define unique cell recognition. Proc Natl Acad Sci U S A 2020; 117:24813-24824. [PMID: 32963097 DOI: 10.1073/pnas.1921983117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thousands of Down syndrome cell adhesion molecule (Dscam1) isoforms and ∼60 clustered protocadhrein (cPcdh) proteins are required for establishing neural circuits in insects and vertebrates, respectively. The strict homophilic specificity exhibited by these proteins has been extensively studied and is thought to be critical for their function in neuronal self-avoidance. In contrast, significantly less is known about the Dscam1-related family of ∼100 shortened Dscam (sDscam) proteins in Chelicerata. We report that Chelicerata sDscamα and some sDscamβ protein trans interactions are strictly homophilic, and that the trans interaction is meditated via the first Ig domain through an antiparallel interface. Additionally, different sDscam isoforms interact promiscuously in cis via membrane proximate fibronectin-type III domains. We report that cell-cell interactions depend on the combined identity of all sDscam isoforms expressed. A single mismatched sDscam isoform can interfere with the interactions of cells that otherwise express an identical set of isoforms. Thus, our data support a model by which sDscam association in cis and trans generates a vast repertoire of combinatorial homophilic recognition specificities. We propose that in Chelicerata, sDscam combinatorial specificity is sufficient to provide each neuron with a unique identity for self-nonself discrimination. Surprisingly, while sDscams are related to Drosophila Dscam1, our results mirror the findings reported for the structurally unrelated vertebrate cPcdh. Thus, our findings suggest a remarkable example of convergent evolution for the process of neuronal self-avoidance and provide insight into the basic principles and evolution of metazoan self-avoidance and self-nonself discrimination.
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20
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Laflamme OD, Lemieux M, Thiry L, Bretzner F. DSCAM Mutation Impairs Motor Cortex Network Dynamic and Voluntary Motor Functions. Cereb Cortex 2020; 29:2313-2330. [PMID: 29718256 DOI: 10.1093/cercor/bhy097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 01/25/2023] Open
Abstract
While it is well known that netrin-1 and its receptors UNC5 and UNC40 family members are involved in the normal establishment of the motor cortex and its corticospinal tract, less is known about its other receptor Down syndrome cell adherence molecule (DSCAM). DSCAM is expressed in the developing motor cortex, regulates axonal outgrowth of cortical neurons, and its mutation impairs the dendritic arborization of cortical neurons, thus suggesting that it might be involved in the normal development and functioning of the motor cortex. In comparison to WT littermates, DSCAM2J mutant mice slipped and misplaced their paw while walking on the rungs of a horizontal ladder, and exhibited more difficulties in stepping over an obstacle while walking at slow speed. Anterograde tracing showed a normal pyramidal decussation and corticospinal projection, but a more dorsal distribution of their axonal terminals in the spinal gray matter. Intracortical microstimulations showed a reduced corticospinal and intracortical efficacy, whereas stimulations of the pyramidal tract revealed a normal spinal efficacy and excitability of corticospinal tract axons, thus arguing for a dysfunctional cortical development. Our study reveals impairment of the network dynamics within the motor cortex, reducing corticospinal drive and impairing voluntary locomotor functions upon DSCAM2J mutation.
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Affiliation(s)
- Olivier D Laflamme
- Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec, CHUL, 2705 Boul. Laurier, Québec, Canada
| | - Maxime Lemieux
- Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec, CHUL, 2705 Boul. Laurier, Québec, Canada
| | - Louise Thiry
- Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec, CHUL, 2705 Boul. Laurier, Québec, Canada
| | - Frédéric Bretzner
- Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec, CHUL, 2705 Boul. Laurier, Québec, Canada.,Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, Canada
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21
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Flores-Flores M, Moreno-García L, Castro-Martínez F, Nahmad M. Cystathionine β-synthase Deficiency Impairs Vision in the Fruit Fly, Drosophila melanogaster. Curr Eye Res 2020; 46:600-605. [PMID: 32865440 DOI: 10.1080/02713683.2020.1818262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Deficiency in Cystathionine β-synthase (CBS) leads to an abnormal accumulation of homocysteine and results in classical homocystinuria, a multi-systemic disorder that affects connective tissue, muscles, the central nervous system, and the eyes. However, the genetic players and mechanisms underlying vision alterations in patients with homocystinuria are little understood. MATERIALS AND METHODS The fruit fly, Drosophila melanogaster, is a useful system to investigate the genetic basis of several human diseases, but no study to date has used Drosophila as model of homocystinuria. Here, we use Drosophila genetic tools to down-regulate CBS expression and evaluate its behavioral response to light. RESULTS We show that CBS-deficient flies do not display the normal stereotypical behavior of attraction towards a luminous source, known as phototaxis. This behavior cannot be attributed to a motor or olfactory deficiency, but it is most likely related to a lower visual acuity. CBS-deficient flies are overall smaller, but smaller eyes do not explain their lack of phototactic response. CONCLUSIONS The vision phenotype of CBS knock-down flies is consistent with severe myopia in homocystinuria patients. We propose to use Drosophila as a model to investigate ocular manifestations underlying homocystinuria.
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Affiliation(s)
- Marycruz Flores-Flores
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, Mexico City, Mexico
| | - Leonardo Moreno-García
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, Mexico City, Mexico
| | - Felipe Castro-Martínez
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, Mexico City, Mexico
| | - Marcos Nahmad
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, Mexico City, Mexico
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22
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Zhang Z, So K, Peterson R, Bauer M, Ng H, Zhang Y, Kim JH, Kidd T, Miura P. Elav-Mediated Exon Skipping and Alternative Polyadenylation of the Dscam1 Gene Are Required for Axon Outgrowth. Cell Rep 2020; 27:3808-3817.e7. [PMID: 31242415 PMCID: PMC7092717 DOI: 10.1016/j.celrep.2019.05.083] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 04/18/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022] Open
Abstract
Many metazoan genes express alternative long 3′ UTR isoforms in the nervous system, but their functions remain largely unclear. In Drosophila melanogaster, the Dscam1 gene generates short and long (Dscam1-L) 3′ UTR isoforms because of alternative polyadenylation (APA). Here, we found that the RNA-binding protein Embryonic Lethal Abnormal Visual System (Elav) impacts Dscam1 biogenesis at two levels, including regulation of long 3′ UTR biogenesis and skipping of an upstream exon (exon 19). MinION long-read sequencing confirmed the connectivity of this alternative splicing event to the long 3′ UTR. Knockdown or CRISPR deletion of Dscam1-L impaired axon outgrowth in Drosophila. The Dscam1 long 3′ UTR was found to be required for correct Elav-mediated skipping of exon 19. Elav thus co-regulates APA and alternative splicing to generate specific Dscam1 transcripts that are essential for neural development. This coupling of APA to alternative splicing might represent a new class of regulated RNA processing. Like most metazoan genes, Dscam1 expresses alternative short and long 3′ UTR mRNAs. Zhang et al. find that loss of Dscam1 long 3′ UTR transcripts impairs axon outgrowth in Drosophila. Long-read sequencing reveals that these long 3′ UTR mRNAs preferentially skip an upstream exon, altering Dscam1 amino acid sequence.
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Affiliation(s)
- Zhiping Zhang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Kevin So
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Ryan Peterson
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Matthew Bauer
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Henry Ng
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Yong Zhang
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Jung Hwan Kim
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Thomas Kidd
- Department of Biology, University of Nevada, Reno, Reno, NV, USA
| | - Pedro Miura
- Department of Biology, University of Nevada, Reno, Reno, NV, USA.
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23
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Ng TH, Kurtz J. Dscam in immunity: A question of diversity in insects and crustaceans. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 105:103539. [PMID: 31734281 DOI: 10.1016/j.dci.2019.103539] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 06/10/2023]
Abstract
In insects and crustaceans, thousands of Down syndrome cell adhesion molecules (Dscam) can be generated by alternative splicing of variable exons from a single-locus gene, Dscam-hv. This extraordinarily versatile gene (38,016 protein isoforms produced in Drosophila) was first proposed to be involved in exon guidance and subsequently implicated in immunity as a hypervariable immune molecule. Almost 20 y after discovery of Dscam-hv, there have been many studies in insects and crustaceans regarding roles of Dscam in immunity, with many similarities and concurrently, many differences. Here, we review the current status of Dscam-hv, presented as a comparison of similarities and differences in insects and crustaceans and discuss hypotheses of Dscam functions in immunity.
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Affiliation(s)
- Tze Hann Ng
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany.
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24
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Alvarez-Lee A, Martínez-Díaz SF, Gutiérrez-Rivera JN, Lanz-Mendoza H. Induction of innate immune response in whiteleg shrimp (Litopenaeus vannamei) embryos. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 105:103577. [PMID: 31852626 DOI: 10.1016/j.dci.2019.103577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/12/2019] [Accepted: 12/14/2019] [Indexed: 06/10/2023]
Abstract
The immune response of commercially relevant marine invertebrates has been extensively studied, in search of new disease-control strategies. Immune training is considered a novel approach that could help improve resistance to different pathogens. Here, we stimulated the white shrimp (Litopenaeus vannamei) during embryo development by exposure to heat-killed bacteria and evaluated their effect on hatching, larval development, and the expression of immune-related genes. In addition, we evaluated its impact on the response of shrimp nauplii during a challenge with Vibrio parahaemolyticus. We observed that the percentage of hatching and the resistance to bacterial infection increased due to the treatment of embryos with heat-killed cells of Vibrio and Bacillus. Apparently different stimuli could generate a differential pattern of gene expression, e.g., Vibrio induced a strong effector immune response whereas Bacillus elicited a protective immune profile. In addition, each response was triggered by molecular patterns detected in the environment. The results obtained in this study provide new insights for immune training to improve shrimp farming.
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Affiliation(s)
- Angélica Alvarez-Lee
- Instituto Politécnico Nacional-Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Politecnico Nacional SN, Playa Palo de Santa Rita, 23096, La Paz, B.C.S, Mexico
| | - Sergio F Martínez-Díaz
- Instituto Politécnico Nacional-Centro Interdisciplinario de Ciencias Marinas, Av. Instituto Politecnico Nacional SN, Playa Palo de Santa Rita, 23096, La Paz, B.C.S, Mexico.
| | - Jesus Neftalí Gutiérrez-Rivera
- Centro de Investigaciones Biológicas del Noroeste, Mar Bermejo 195, Colonia Playa Palo de Santa Rita, 23090, La Paz, BCS, Mexico
| | - Humberto Lanz-Mendoza
- Instituto Nacional de Salud Pública, Avenida Universidad No. 655 Colonia Santa María Ahuacatitlán, Cerrada Los Pinos y Caminera, 62100, Cuernavaca, MOR, Mexico.
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25
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Horton MB, Hawkins ED, Heinzel S, Hodgkin PD. Speculations on the evolution of humoral adaptive immunity. Immunol Cell Biol 2020; 98:439-448. [PMID: 32133683 PMCID: PMC7383592 DOI: 10.1111/imcb.12323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 02/01/2023]
Abstract
The protection of a multicellular organism from infection, at both cell and humoral levels, has been a tremendous driver of gene selection and cellular response strategies. Here we focus on a critical event in the development of humoral immunity: The transition from principally innate responses to a system of adaptive cell selection, with all the attendant mechanical problems that must be solved in order for it to work effectively. Here we review recent advances, but our major goal is to highlight that the development of adaptive immunity resulted from the adoption, reuse and repurposing of an ancient, autonomous cellular program that combines and exploits three titratable cellular fate timers. We illustrate how this common cell machinery recurs and appears throughout biology, and has been essential for the evolution of complex organisms, at many levels of scale.
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Affiliation(s)
- Miles B Horton
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Edwin D Hawkins
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Susanne Heinzel
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Philip D Hodgkin
- Division of Immunology, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
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26
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Chauhan P, Gupta R, Jain BP, Pandey S, Goswami SK. Subcellular dynamics of variants of SG2NA in NIH3T3 fibroblasts. Cell Biol Int 2019; 44:637-650. [PMID: 31773824 DOI: 10.1002/cbin.11264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
SG2NA, a WD40 repeat protein of the Striatin subfamily, has four splicing and one messenger RNA edit variants. It is fast emerging as a scaffold for multimeric signaling complexes with roles in tissue development and disease. The green fluorescent protein (GFP)-tagged variants of SG2NA were ectopically expressed in NIH3T3 cells and their modulation by serum and GSK3β-ERK signaling were monitored. The 87, 78, and 35 kDa variants showed a biphasic modulation by serum till 24 h but the 52 kDa variant remained largely unresponsive. Inhibition of phosphatases by okadaic acid increased the levels of the endogenous 78 kDa and the ectopically expressed GFP-tagged 87 and 78 kDa SG2NAs. Contrastingly, okadaic acid treatment reduced the level of GFP-tagged 35 kDa SG2NA, suggesting differential modes of their stability through phosphorylation-dephosphorylation. The inhibition of GSK3β by LiCl showed a gradual decrease in the levels of 78 kDa. In the case of the other variants viz, GFP-tagged 35, 52, and 87 kDa, inhibition of GSK3β caused an initial increase followed by a decrease with a subtle difference in kinetics and intensities. Similar results were also seen upon inhibition of GSK3β by small interfering RNA. All the variants showed an increase followed by a decrease upon inhibition of extracellular-signal-regulated-kinase (ERK). These variants are localized in the plasma membrane, endoplasmic reticulum, mitochondria, and the nucleus with different propensities and no discernable subcellular distribution was seen upon stimulation by serum and the inhibition of phosphatases, GSK3β, and ERK. Taken together, the variants of SG2NA are modulated by the kinase-phosphatase network in a similar but characteristic manner.
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Affiliation(s)
- Pooja Chauhan
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,Department of Microbiology and Molecular Genetics, Hadassah Medical School, Institute of Medical Research Israel-Canada, The Hebrew University of Jerusalem, POB 12272, Jerusalem, 91120, Israel
| | - Richa Gupta
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
| | - Buddhi P Jain
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University Bihar, Motihari, 845401, India
| | - Shweta Pandey
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,APSGMNS Govt PG College, Kawardha, Chhatishgarh
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
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27
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Apitanyasai K, Huang SW, Ng TH, He ST, Huang YH, Chiu SP, Tseng KC, Lin SS, Chang WC, Baldwin-Brown JG, Long AD, Lo CF, Yu HT, Wang HC. The gene structure and hypervariability of the complete Penaeus monodon Dscam gene. Sci Rep 2019; 9:16595. [PMID: 31719551 PMCID: PMC6851185 DOI: 10.1038/s41598-019-52656-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/17/2019] [Indexed: 12/19/2022] Open
Abstract
Using two advanced sequencing approaches, Illumina and PacBio, we derive the entire Dscam gene from an M2 assembly of the complete Penaeus monodon genome. The P. monodon Dscam (PmDscam) gene is ~266 kbp, with a total of 44 exons, 5 of which are subject to alternative splicing. PmDscam has a conserved architectural structure consisting of an extracellular region with hypervariable Ig domains, a transmembrane domain, and a cytoplasmic tail. We show that, contrary to a previous report, there are in fact 26, 81 and 26 alternative exons in N-terminal Ig2, N-terminal Ig3 and the entirety of Ig7, respectively. We also identified two alternatively spliced exons in the cytoplasmic tail, with transmembrane domains in exon variants 32.1 and 32.2, and stop codons in exon variants 44.1 and 44.2. This means that alternative splicing is involved in the selection of the stop codon. There are also 7 non-constitutive cytoplasmic tail exons that can either be included or skipped. Alternative splicing and the non-constitutive exons together produce more than 21 million isoform combinations from one PmDscam locus in the P. monodon gene. A public-facing database that allows BLAST searches of all 175 exons in the PmDscam gene has been established at http://pmdscam.dbbs.ncku.edu.tw/.
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Affiliation(s)
- Kantamas Apitanyasai
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shiao-Wei Huang
- Department of Life Sciences, National Taiwan University, Taipei, Taiwan
| | - Tze Hann Ng
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Ting He
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Hsun Huang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Shen-Po Chiu
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Kuan-Chien Tseng
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Shun Lin
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Wen-Chi Chang
- Institute of Tropical Plant Sciences, National Cheng Kung University, Tainan, Taiwan
| | - James G Baldwin-Brown
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, USA
| | - Anthony D Long
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, California, USA
| | - Chu-Fang Lo
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan
| | - Hon-Tsen Yu
- Department of Life Sciences, National Taiwan University, Taipei, Taiwan
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan. .,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan.
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28
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Meijers R, Smock RG, Zhang Y, Wang JH. Netrin Synergizes Signaling and Adhesion through DCC. Trends Biochem Sci 2019; 45:6-12. [PMID: 31704057 DOI: 10.1016/j.tibs.2019.10.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/09/2019] [Accepted: 10/14/2019] [Indexed: 01/08/2023]
Abstract
Netrin is a prototypical axon guidance cue. Structural studies have revealed how netrin interacts with the deleted in colorectal cancer (DCC) receptor, other receptors, and co-factors for signaling. Recently, genetic studies suggested that netrin is involved in neuronal haptotaxis, which requires a reversible adhesion process. Structural data indicate that netrin can also mediate trans-adhesion between apposing cells decorated with its receptors on the condition that the auxiliary guidance cue draxin is present. Here, we propose that netrin is involved in conditional adhesion, a reversible and localized process that can contribute to cell adhesion and migration. We suggest that netrin-mediated adhesion and signaling are linked, and that local environmental factors in the ventricular zone, the floor plate, or other tissues coordinate its function.
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Affiliation(s)
- Rob Meijers
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, Notkestrasse 85, D-22607 Hamburg, Germany.
| | - Robert G Smock
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, Notkestrasse 85, D-22607 Hamburg, Germany
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 China
| | - Jia-Huai Wang
- State Key Laboratory of Membrane Biology, College of Life Sciences, Peking University, Beijing 100871 China; Department of Medical Oncology and Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA.
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29
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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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30
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Chen X, Jiang Y, Wang J, Liu Y, Xiao M, Song C, Bai Y, Yinuo Han N, Han F. Synapse impairment associated with enhanced apoptosis in post-traumatic stress disorder. Synapse 2019; 74:e22134. [PMID: 31562782 DOI: 10.1002/syn.22134] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/31/2022]
Abstract
Synapse impairment is associated with post-traumatic stress disorder (PTSD), which is characterized by enhanced apoptosis in the hippocampus, amygdala, and other brain regions. However, there are no detailed studies on the relationship between apoptosis and synaptic connectivity in PTSD. In this review, we discuss results from various studies describing the synaptic changes observed in the PTSD brain. A decreased number of dendrites/spines or increased number of immature spines in the hippocampus, medial prefrontal cortex, and other brain regions has been reported. Studies on axon guidance, myelination, and the cytoskeleton suggest that PTSD may involve axon overgrowth and overbranching. Apoptosis affects synapse formation; low levels of caspase maintain the balance between growth cone attraction and repulsion and inhibit axon elongation. PTSD enhances neuronal apoptosis through caspase activation, which disrupts the balance between growth cone attraction and repulsion and alters growth cone trajectory, leading to axon mistargeting. Meanwhile, caspase activation induces dendritic pruning and dendrite degeneration. These events contribute to the formation of fewer and aberrant synapses, which is associated with enhanced apoptosis in PTSD.
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Affiliation(s)
- Xinzhao Chen
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Yifan Jiang
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Jiayu Wang
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Yishu Liu
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Menglei Xiao
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Congshan Song
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Yu Bai
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
| | - Nancy Yinuo Han
- Faculty of Science, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fang Han
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical College, China Medical University, Shenyang, China
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31
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Morimoto K, Nakajima K. Role of the Immune System in the Development of the Central Nervous System. Front Neurosci 2019; 13:916. [PMID: 31551681 PMCID: PMC6735264 DOI: 10.3389/fnins.2019.00916] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/16/2019] [Indexed: 01/01/2023] Open
Abstract
The central nervous system (CNS) and the immune system are both intricate and highly organized systems that regulate the entire body, with both sharing certain common features in developmental mechanisms and operational modes. It is known that innate immunity-related molecules, such as cytokines, toll-like receptors, the complement family, and acquired immunity-related molecules, such as the major histocompatibility complex and antibody receptors, are also expressed in the brain and play important roles in brain development. Moreover, although the brain has previously been regarded as an immune-privileged site, it is known to contain lymphatic vessels. Not only microglia but also lymphocytes regulate cognition and play a vital role in the formation of neuronal circuits. This review provides an overview of the function of immune cells and immune molecules in the CNS, with particular emphasis on their effect on neural developmental processes.
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Affiliation(s)
- Keiko Morimoto
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
| | - Kazunori Nakajima
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan
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32
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Ng TH, Kumar R, Apitanyasai K, He ST, Chiu SP, Wang HC. Selective expression of a "correct cloud" of Dscam in crayfish survivors after second exposure to the same pathogen. FISH & SHELLFISH IMMUNOLOGY 2019; 92:430-437. [PMID: 31200075 DOI: 10.1016/j.fsi.2019.06.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 06/09/2023]
Abstract
Arthropod hypervariable Dscam (Down syndrome cell adhesion molecule) may be involved in adaptive-like immune characteristics, namely immune priming, enabling the host to "learn" and "remember" pathogens previously encountered in arthropods. However, expression of Dscam in immune-primed arthropods after a second challenge has apparently not been confirmed. Herein, working with Dscam of Australian freshwater crayfish (Cherax quadricarinatus, i.e. CqDscam), we further investigated whether immune priming is mediated by "clouds" of appropriate (or "correct") CqDscam isoforms. In crayfish that survived a first WSSV challenge (immune priming), long-lasting CqDscam expression remained higher after a second WSSV challenge. Selective CqDscam isoforms were also induced after both challenges. Based on pathogen binding assays, these WSSV-induced CqDscam isoforms had a higher WSSV binding ability, perhaps mainly mediated by Ig3-spliced variants. We therefore hypothesized that in these crayfish survivors, an unknown selection process was generating a "correct cloud" of CqDscam against a previously encountered pathogen.
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Affiliation(s)
- Tze Hann Ng
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Ramya Kumar
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Kantamas Apitanyasai
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Ting He
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Shen-Po Chiu
- Department of Life Science, National Cheng Kung University, Tainan, Taiwan
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, National Cheng Kung University, Tainan, Taiwan; International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan.
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33
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Wan ZC, Li D, Li XJ, Zhu YT, Gao TH, Li WW, Wang Q. B52 promotes alternative splicing of Dscam in Chinese mitten crab, Eriocheir sinensis. FISH & SHELLFISH IMMUNOLOGY 2019; 87:460-469. [PMID: 30685464 DOI: 10.1016/j.fsi.2019.01.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/15/2019] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
B52 is a member of the classical serine/arginine (SR)-rich proteins, which are phylogenetically conserved and play significant roles in mRNA maturation, including alternative splicing. In the present study, the docking site, selector sequences and locus control region of the Chinese mitten crab (Eriocheir sinensis) Down syndrome cell adhesion molecule (EsDscam) were identified. Alternative splicing of Dscam is essential to generate different isoforms. We also isolated and characterised the B52 gene from E. sinensis (EsB52). The 876 bp open reading frame of EsB52 encodes a 291 amino acid residue polypeptide, and EsB52 has two RNA recognition motifs (RRMs) at the N-terminus and an arginine/serine-rich domain at the C-terminus. Each RRM contains two degenerate short submotifs, RNP-1 and RNP2. Analysis of tissue distribution revealed that EsB52 mRNA expression was widespread in all tested tissues, and especially high in brain and hemocytes. In hemocytes, EsB52 was upregulated significantly after stimulation with pathogen-associated molecular patterns and bacteria. Furthermore, EsB52 RNAi decreased the number of Ig7 inclusion in mRNA rather than Ig2 or Ig3. Taken together, these findings suggest that EsB52 acts as an alternative splicing activator of EsDscam.
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Affiliation(s)
- Zhi-Cheng Wan
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Dan Li
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Xue-Jie Li
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - You-Ting Zhu
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China
| | - Tian-Heng Gao
- Institute of Marine Biology, College of Oceanography, Hohai University, Nanjing, Jiangsu, China
| | - Wei-Wei Li
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China.
| | - Qun Wang
- State Key Laboratory of Estuarine and Coastal Research, Laboratory of Invertebrate Immunological Defense and Reproductive Biology, School of Life Sciences, East China Normal University, Shanghai, China.
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Biasoli D, Compston-Garnett L, Ricketts SL, Birand Z, Courtay-Cahen C, Fineberg E, Arendt M, Boerkamp K, Melin M, Koltookian M, Murphy S, Rutteman G, Lindblad-Toh K, Starkey M. A synonymous germline variant in a gene encoding a cell adhesion molecule is associated with cutaneous mast cell tumour development in Labrador and Golden Retrievers. PLoS Genet 2019; 15:e1007967. [PMID: 30901340 PMCID: PMC6447235 DOI: 10.1371/journal.pgen.1007967] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 04/03/2019] [Accepted: 01/16/2019] [Indexed: 02/06/2023] Open
Abstract
Mast cell tumours are the most common type of skin cancer in dogs, representing a significant concern in canine health. The molecular pathogenesis is largely unknown, but breed-predisposition for mast cell tumour development suggests the involvement of inherited genetic risk factors in some breeds. In this study, we aimed to identify germline risk factors associated with the development of mast cell tumours in Labrador Retrievers, a breed with an elevated risk of mast cell tumour development. Using a methodological approach that combined a genome-wide association study, targeted next generation sequencing, and TaqMan genotyping, we identified a synonymous variant in the DSCAM gene on canine chromosome 31 that is associated with mast cell tumours in Labrador Retrievers. DSCAM encodes a cell-adhesion molecule. We showed that the variant has no effect on the DSCAM mRNA level but is associated with a significant reduction in the level of the DSCAM protein, suggesting that the variant affects the dynamics of DSCAM mRNA translation. Furthermore, we showed that the variant is also associated with mast cell tumours in Golden Retrievers, a breed that is closely related to Labrador Retrievers and that also has a predilection for mast cell tumour development. The variant is common in both Labradors and Golden Retrievers and consequently is likely to be a significant genetic contributor to the increased susceptibility of both breeds to develop mast cell tumours. The results presented here not only represent an important contribution to the understanding of mast cell tumour development in dogs, as they highlight the role of cell adhesion in mast cell tumour tumourigenesis, but they also emphasise the potential importance of the effects of synonymous variants in complex diseases such as cancer. The combination of various genetic and environmental risk factors makes the understanding of the molecular circuitry behind complex diseases, like cancer, a major challenge. The homogeneous nature of pedigree dog breed genomes makes these dogs ideal for the identification of both simple disease-causing genetic variants and genetic risk factors for complex diseases. Mast cell tumours are the most common type of canine skin cancer, and one of the most common cancers affecting dogs of most breeds. Several breeds, including Labrador Retrievers (which represent one of the most popular dog breeds), have an elevated risk of mast cell tumour development. Here, by using a methodological approach that combined different techniques, we identified a common inherited synonymous variant, that predisposes Labrador Retrievers to mast cell tumour development. Interestingly, we showed that this variant, despite its synonymous nature, appears to have an effect on translation dynamics as it is associated with reduced levels of DSCAM, a cell adhesion molecule. The results presented here reveal dysregulation of cell adhesion to be an important factor in mast cell tumour pathogenesis, and also highlight the important role that synonymous variants can play in complex diseases.
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Affiliation(s)
| | | | | | | | | | | | - Maja Arendt
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Kim Boerkamp
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands
| | - Malin Melin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Michele Koltookian
- Broad Institute of MIT and Harvard, Cambridge, MA, United States of America
| | - Sue Murphy
- Animal Health Trust, Newmarket, United Kingdom
| | - Gerard Rutteman
- Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands
- Veterinary Specialist Centre De Wagenrenk, Wageningen, The Netherlands
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Broad Institute of MIT and Harvard, Cambridge, MA, United States of America
| | - Mike Starkey
- Animal Health Trust, Newmarket, United Kingdom
- * E-mail:
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35
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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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Styfhals R, Seuntjens E, Simakov O, Sanges R, Fiorito G. In silico Identification and Expression of Protocadherin Gene Family in Octopus vulgaris. Front Physiol 2019; 9:1905. [PMID: 30692932 PMCID: PMC6339937 DOI: 10.3389/fphys.2018.01905] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 12/18/2018] [Indexed: 11/24/2022] Open
Abstract
Connecting millions of neurons to create a functional neural circuit is a daunting challenge. Vertebrates developed a molecular system at the cell membrane to allow neurons to recognize each other by distinguishing self from non-self through homophilic protocadherin interactions. In mammals, the protocadherin gene family counts about 50 different genes. By hetero-multimerization, protocadherins are capable of generating an impressive number of molecular interfaces. Surprisingly, in the California two-spot octopus, Octopus bimaculoides, an invertebrate belonging to the Phylum Mollusca, over 160 protocadherins (PCDHs) have been identified. Here we briefly discuss the role of PCDHs in neural wiring and conduct a comparative study of the protocadherin gene family in two closely related octopus species, Octopus vulgaris and O. bimaculoides. A first glance at the expression patterns of protocadherins in O. vulgaris is also provided. Finally, we comment on PCDH evolution in the light of invertebrate nervous system plasticity.
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Affiliation(s)
- Ruth Styfhals
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy.,Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Eve Seuntjens
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Oleg Simakov
- Department of Molecular Evolution and Development, University of Vienna, Vienna, Austria
| | - Remo Sanges
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy.,Computational Genomics Laboratory, Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Graziano Fiorito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy
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37
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Uliano-Silva M, Dondero F, Dan Otto T, Costa I, Lima NCB, Americo JA, Mazzoni CJ, Prosdocimi F, Rebelo MDF. A hybrid-hierarchical genome assembly strategy to sequence the invasive golden mussel, Limnoperna fortunei. Gigascience 2018; 7:4750781. [PMID: 29267857 PMCID: PMC5836269 DOI: 10.1093/gigascience/gix128] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Abstract
Background For more than 25 years, the golden mussel, Limnoperna fortunei, has aggressively invaded South American freshwaters, having travelled more than 5000 km upstream across 5 countries. Along the way, the golden mussel has outcompeted native species and economically harmed aquaculture, hydroelectric powers, and ship transit. We have sequenced the complete genome of the golden mussel to understand the molecular basis of its invasiveness and search for ways to control it. Findings We assembled the 1.6-Gb genome into 20 548 scaffolds with an N50 length of 312 Kb using a hybrid and hierarchical assembly strategy from short and long DNA reads and transcriptomes. A total of 60 717 coding genes were inferred from a customized transcriptome-trained AUGUSTUS run. We also compared predicted protein sets with those of complete molluscan genomes, revealing an exacerbation of protein-binding domains in L. fortunei. Conclusions We built one of the best bivalve genome assemblies available using a cost-effective approach using Illumina paired-end, mate-paired, and PacBio long reads. We expect that the continuous and careful annotation of L. fortunei's genome will contribute to the investigation of bivalve genetics, evolution, and invasiveness, as well as to the development of biotechnological tools for aquatic pest control.
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Affiliation(s)
- Marcela Uliano-Silva
- Carlos Chagas Filho Biophysics Institute (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research, Berlin, Germany
| | - Francesco Dondero
- Department of Science and Technological Innovation (DiSIT), Università del Piemonte Orientale Amedeo Avogadro, Vercelli-Novara-Alessandria, Italy
| | - Thomas Dan Otto
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK.,Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Igor Costa
- Leopoldo de Meis Biomedical Biochemistry Institute (IBqM), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nicholas Costa Barroso Lima
- Leopoldo de Meis Biomedical Biochemistry Institute (IBqM), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Bioinformatics Laboratory (LabInfo) of the National Laboratory for Scientific Computing, Petrópolis, Rio de Janeiro, Brazil
| | - Juliana Alves Americo
- Carlos Chagas Filho Biophysics Institute (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Camila Junqueira Mazzoni
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.,Berlin Center for Genomics in Biodiversity Research, Berlin, Germany
| | - Francisco Prosdocimi
- Leopoldo de Meis Biomedical Biochemistry Institute (IBqM), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mauro de Freitas Rebelo
- Carlos Chagas Filho Biophysics Institute (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Julien DP, Chan AW, Barrios J, Mathiaparanam J, Douglass A, Wolman MA, Sagasti A. Zebrafish expression reporters and mutants reveal that the IgSF cell adhesion molecule Dscamb is required for feeding and survival. J Neurogenet 2018; 32:336-352. [PMID: 30204029 DOI: 10.1080/01677063.2018.1493479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Down syndrome cell adhesion molecules (DSCAMs) are broadly expressed in nervous systems and play conserved roles in programmed cell death, neuronal migration, axon guidance, neurite branching and spacing, and synaptic targeting. However, DSCAMs appear to have distinct functions in different vertebrate animals, and little is known about their functions outside the retina. We leveraged the genetic tractability and optical accessibility of larval zebrafish to investigate the expression and function of a DSCAM family member, dscamb. Using targeted genome editing to create transgenic reporters and loss-of-function mutant alleles, we discovered that dscamb is expressed broadly throughout the brain, spinal cord, and peripheral nervous system, but is not required for overall structural organization of the brain. Despite the absence of obvious anatomical defects, homozygous dscamb mutants were deficient in their ability to ingest food and rarely survived to adulthood. Thus, we have discovered a novel function for dscamb in feeding behavior. The mutant and transgenic lines generated in these studies will provide valuable tools for identifying the molecular and cellular bases of these behaviors.
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Affiliation(s)
- Donald P Julien
- a Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute , University of California , Los Angeles , CA , USA
| | - Alex W Chan
- a Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute , University of California , Los Angeles , CA , USA
| | - Joshua Barrios
- b Department of Neurobiology and Anatomy , University of Utah , Salt Lake City , UT , USA
| | - Jaffna Mathiaparanam
- c Department of Integrative Biology , University of Wisconsin , Madison , WI , USA
| | - Adam Douglass
- b Department of Neurobiology and Anatomy , University of Utah , Salt Lake City , UT , USA
| | - Marc A Wolman
- c Department of Integrative Biology , University of Wisconsin , Madison , WI , USA
| | - Alvaro Sagasti
- a Department of Molecular, Cell and Developmental Biology and Molecular Biology Institute , University of California , Los Angeles , CA , USA
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A genome-wide search for new imprinted genes in the human placenta identifies DSCAM as the first imprinted gene on chromosome 21. Eur J Hum Genet 2018; 27:49-60. [PMID: 30206355 DOI: 10.1038/s41431-018-0267-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 07/16/2018] [Accepted: 08/23/2018] [Indexed: 11/08/2022] Open
Abstract
We identified, through a genome-wide search for new imprinted genes in the human placenta, DSCAM (Down Syndrome Cellular Adhesion Molecule) as a paternally expressed imprinted gene. Our work revealed the presence of a Differentially Methylated Region (DMR), located within intron 1 that might regulate the imprinting in the region. This DMR showed a maternal allele methylation, compatible with its paternal expression. We showed that DSCAM is present in endothelial cells and the syncytiotrophoblast layer of the human placenta. In mouse, Dscam expression is biallelic in foetal brain and placenta excluding any possible imprinting in these tissues. This gene encodes a cellular adhesion molecule mainly known for its role in neurone development but its function in the placenta remains unclear. We report here the first imprinted gene located on human chromosome 21 with potential clinical implications.
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40
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Chou HY, Lun CM, Smith LC. SpTransformer proteins from the purple sea urchin opsonize bacteria, augment phagocytosis, and retard bacterial growth. PLoS One 2018; 13:e0196890. [PMID: 29738524 PMCID: PMC5940198 DOI: 10.1371/journal.pone.0196890] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/20/2018] [Indexed: 01/05/2023] Open
Abstract
The purple sea urchin, Strongylocentrotus purpuratus, has a complex and robust immune system that is mediated by a number of multi-gene families including the SpTransformer (SpTrf) gene family (formerly Sp185/333). In response to immune challenge from bacteria and various pathogen-associated molecular patterns, the SpTrf genes are up-regulated in sea urchin phagocytes and express a diverse array of SpTrf proteins. We show here that SpTrf proteins from coelomocytes and isolated by nickel affinity (cNi-SpTrf) bind to Gram-positive and Gram-negative bacteria and to Baker's yeast, Saccharomyces cerevisiae, with saturable kinetics and specificity. cNi-SpTrf opsonization of the marine bacteria, Vibrio diazotrophicus, augments phagocytosis, however, opsonization by the recombinant protein, rSpTrf-E1, does not. Binding by cNi-SpTrf proteins retards growth rates significantly for several species of bacteria. SpTrf proteins, previously thought to be strictly membrane-associated, are secreted from phagocytes in short term cultures and bind V. diazotrophicus that are located both outside of and within phagocytes. Our results demonstrate anti-microbial activities of native SpTrf proteins and suggest variable functions among different SpTrf isoforms. Multiple isoforms may act synergistically to detect a wide array of pathogens and provide flexible and efficient host immunity.
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Affiliation(s)
- Hung-Yen Chou
- Department of Biological Sciences, George Washington University, Washington, DC, United States of America
| | - Cheng Man Lun
- Department of Biological Sciences, George Washington University, Washington, DC, United States of America
| | - L. Courtney Smith
- Department of Biological Sciences, George Washington University, Washington, DC, United States of America
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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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Stachowicz K. The role of DSCAM in the regulation of synaptic plasticity: possible involvement in neuropsychiatric disorders. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Armitage SAO, Kurtz J, Brites D, Dong Y, Du Pasquier L, Wang HC. Dscam1 in Pancrustacean Immunity: Current Status and a Look to the Future. Front Immunol 2017. [PMID: 28649249 PMCID: PMC5465998 DOI: 10.3389/fimmu.2017.00662] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Down syndrome cell adhesion molecule 1 (Dscam1) gene is an extraordinary example of diversity: by combining alternatively spliced exons, thousands of isoforms can be produced from just one gene. So far, such diversity in this gene has only been found in insects and crustaceans, and its essential part in neural wiring has been well-characterized for Drosophila melanogaster. Ten years ago evidence from D. melanogaster showed that the Dscam1 gene is involved in insect immune defense and work on Anopheles gambiae indicated that it is a hypervariable immune receptor. These exciting findings showed that via processes of somatic diversification insects have the possibility to produce unexpected immune molecule diversity, and it was hypothesized that Dscam1 could provide the mechanistic underpinnings of specific immune responses. Since these first publications the quest to understand the function of this gene has uncovered fascinating insights from insects and crustaceans. However, we are still far from a complete understanding of how Dscam1 functions in relation to parasites and pathogens and its full relevance for the immune system. In this Hypothesis and Theory article, we first briefly introduce Dscam1 and what we know so far about how it might function in immunity. By focusing on seven questions, we then share our sometimes contrasting thoughts on what the evidence tells us so far, what essential experiments remain to be done, and the future prospects, with the aim to provide a multiangled view on what this fascinating gene has to do with immune defense.
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Affiliation(s)
- Sophie A O Armitage
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Daniela Brites
- Tuberculosis Research Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland.,Zoological Institute, University of Basel, Basel, Switzerland
| | - Yuemei Dong
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, John Hopkins University, Baltimore, MD, United States
| | | | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
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44
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Smooth Muscle Phenotypic Diversity: Effect on Vascular Function and Drug Responses. ADVANCES IN PHARMACOLOGY 2017. [PMID: 28212802 DOI: 10.1016/bs.apha.2016.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
At its simplest resistance to blood flow is regulated by changes in the state of contraction of the vascular smooth muscle (VSM), a function of the competing activities of the myosin kinase and phosphatase determining the phosphorylation and activity of the myosin ATPase motor protein. In contrast, the vascular system of humans and other mammals is incredibly complex and highly regulated. Much of this complexity derives from phenotypic diversity within the smooth muscle, reflected in very differing power outputs and responses to signaling pathways that regulate vessel tone, presumably having evolved over the millennia to optimize vascular function and its control. The highly regulated nature of VSM tone, described as pharmacomechanical coupling, likely underlies the many classes of drugs in clinical use to alter vascular tone through activation or inhibition of these signaling pathways. This review will first describe the phenotypic diversity within VSM, followed by presentation of specific examples of how molecular diversity in signaling, myofilament, and calcium cycling proteins impacts arterial smooth muscle function and drug responses.
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45
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Yue Y, Hou S, Wang X, Zhan L, Cao G, Li G, Shi Y, Zhang P, Hong W, Lin H, Liu B, Shi F, Yang Y, Jin Y. Role and convergent evolution of competing RNA secondary structures in mutually exclusive splicing. RNA Biol 2017; 14:1399-1410. [PMID: 28277933 DOI: 10.1080/15476286.2017.1294308] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Exon or cassette duplication is an important means of expanding protein and functional diversity through mutually exclusive splicing. However, the mechanistic basis of this process in non-arthropod species remains poorly understood. Here, we demonstrate that MRP1 genes underwent tandem exon duplication in Nematoda, Platyhelminthes, Annelida, Mollusca, Arthropoda, Echinodermata, and early-diverging Chordata but not in late-diverging vertebrates. Interestingly, these events were of independent origin in different phyla, suggesting convergent evolution of alternative splicing. Furthermore, we showed that multiple sets of clade-conserved RNA pairings evolved to guide species-specific mutually exclusive splicing in Arthropoda. Importantly, we also identified a similar structural code in MRP exon clusters of the annelid, Capitella teleta, and chordate, Branchiostoma belcheri, suggesting an evolutionarily conserved competing pairing-guided mechanism in bilaterians. Taken together, these data reveal the molecular determinants and RNA pairing-guided evolution of species-specific mutually exclusive splicing spanning more than 600 million years of bilaterian evolution. These findings have a significant impact on our understanding of the evolution of and mechanism underpinning isoform diversity and complex gene structure.
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Affiliation(s)
- Yuan Yue
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Shouqing Hou
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Xiu Wang
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China.,b Institute of Ecology, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Leilei Zhan
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Guozheng Cao
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Guoli Li
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Yang Shi
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Peng Zhang
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Weiling Hong
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Hao Lin
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Baoping Liu
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Feng Shi
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Yun Yang
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. China
| | - Yongfeng Jin
- a Institute of Biochemistry, College of Life Sciences, Zhejiang University , Hangzhou , Zhejiang , P.R. 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: 41] [Impact Index Per Article: 5.9] [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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Arp AP, Hunter WB, Pelz-Stelinski KS. Annotation of the Asian Citrus Psyllid Genome Reveals a Reduced Innate Immune System. Front Physiol 2016; 7:570. [PMID: 27965582 PMCID: PMC5126049 DOI: 10.3389/fphys.2016.00570] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/09/2016] [Indexed: 01/06/2023] Open
Abstract
Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as Huanglongbing. The citrus greening bacteria, Candidatus Liberibacter asiaticus (CLas), is a persistent propagative pathogen transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). Hemipterans characterized to date lack a number of insect immune genes, including those associated with the Imd pathway targeting Gram-negative bacteria. The D. citri draft genome was used to characterize the immune defense genes present in D. citri. Predicted mRNAs identified by screening the published D. citri annotated draft genome were manually searched using a custom database of immune genes from previously annotated insect genomes. Toll and JAK/STAT pathways, general defense genes Dual oxidase, Nitric oxide synthase, prophenoloxidase, and cellular immune defense genes were present in D. citri. In contrast, D. citri lacked genes for the Imd pathway, most antimicrobial peptides, 1,3-β-glucan recognition proteins (GNBPs), and complete peptidoglycan recognition proteins. These data suggest that D. citri has a reduced immune capability similar to that observed in A. pisum, P. humanus, and R. prolixus. The absence of immune system genes from the D. citri genome may facilitate CLas infections, and is possibly compensated for by their relationship with their microbial endosymbionts.
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Affiliation(s)
- Alex P Arp
- Citrus Research and Education Center, Department of Entomology and Nematology, University of Florida Fort Pierce, FL, USA
| | - Wayne B Hunter
- U.S. Horticultural Research Lab, Agricultural Research Service, United State Department of Agriculture Fort Pierce, FL, USA
| | - Kirsten S Pelz-Stelinski
- Citrus Research and Education Center, Department of Entomology and Nematology, University of Florida Fort Pierce, FL, USA
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48
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Goodman KM, Yamagata M, Jin X, Mannepalli S, Katsamba PS, Ahlsén G, Sergeeva AP, Honig B, Sanes JR, Shapiro L. Molecular basis of sidekick-mediated cell-cell adhesion and specificity. eLife 2016; 5. [PMID: 27644106 PMCID: PMC5045292 DOI: 10.7554/elife.19058] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/17/2016] [Indexed: 01/06/2023] Open
Abstract
Sidekick (Sdk) 1 and 2 are related immunoglobulin superfamily cell adhesion proteins required for appropriate synaptic connections between specific subtypes of retinal neurons. Sdks mediate cell-cell adhesion with homophilic specificity that underlies their neuronal targeting function. Here we report crystal structures of Sdk1 and Sdk2 ectodomain regions, revealing similar homodimers mediated by the four N-terminal immunoglobulin domains (Ig1-4), arranged in a horseshoe conformation. These Ig1-4 horseshoes interact in a novel back-to-back orientation in both homodimers through Ig1:Ig2, Ig1:Ig1 and Ig3:Ig4 interactions. Structure-guided mutagenesis results show that this canonical dimer is required for both Sdk-mediated cell aggregation (via trans interactions) and Sdk clustering in isolated cells (via cis interactions). Sdk1/Sdk2 recognition specificity is encoded across Ig1-4, with Ig1-2 conferring the majority of binding affinity and differential specificity. We suggest that competition between cis and trans interactions provides a novel mechanism to sharpen the specificity of cell-cell interactions.
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Affiliation(s)
- Kerry M Goodman
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - Masahito Yamagata
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Xiangshu Jin
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Seetha Mannepalli
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - Phinikoula S Katsamba
- Howard Hughes Medical Institute, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States
| | - Göran Ahlsén
- Howard Hughes Medical Institute, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States
| | - Alina P Sergeeva
- Howard Hughes Medical Institute, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Howard Hughes Medical Institute, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,Department of Medicine, Columbia University, New York, United States.,Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, United States
| | - Joshua R Sanes
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States.,Department of Systems Biology, Columbia University, New York, United States.,Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, United States
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49
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Kim E, Kim Y. Translational Control of Host Gene Expression by a Cys-Motif Protein Encoded in a Bracovirus. PLoS One 2016; 11:e0161661. [PMID: 27598941 PMCID: PMC5012692 DOI: 10.1371/journal.pone.0161661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 08/09/2016] [Indexed: 11/18/2022] Open
Abstract
Translational control is a strategy that various viruses use to manipulate their hosts to suppress acute antiviral response. Polydnaviruses, a group of insect double-stranded DNA viruses symbiotic to some endoparasitoid wasps, are divided into two genera: ichnovirus (IV) and bracovirus (BV). In IV, some Cys-motif genes are known as host translation-inhibitory factors (HTIF). The genome of endoparasitoid wasp Cotesia plutellae contains a Cys-motif gene (Cp-TSP13) homologous to an HTIF known as teratocyte-secretory protein 14 (TSP14) of Microplitis croceipes. Cp-TSP13 consists of 129 amino acid residues with a predicted molecular weight of 13.987 kDa and pI value of 7.928. Genomic DNA region encoding its open reading frame has three introns. Cp-TSP13 possesses six conserved cysteine residues as other Cys-motif genes functioning as HTIF. Cp-TSP13 was expressed in Plutella xylostella larvae parasitized by C. plutellae. C. plutellae bracovirus (CpBV) was purified and injected into non-parasitized P. xylostella that expressed Cp-TSP13. Cp-TSP13 was cloned into a eukaryotic expression vector and used to infect Sf9 cells to transiently express Cp-TSP13. The synthesized Cp-TSP13 protein was detected in culture broth. An overlaying experiment showed that the purified Cp-TSP13 entered hemocytes. It was localized in the cytosol. Recombinant Cp-TSP13 significantly inhibited protein synthesis of secretory proteins when it was added to in vitro cultured fat body. In addition, the recombinant Cp-TSP13 directly inhibited the translation of fat body mRNAs in in vitro translation assay using rabbit reticulocyte lysate. Moreover, the recombinant Cp-TSP13 significantly suppressed cellular immune responses by inhibiting hemocyte-spreading behavior. It also exhibited significant insecticidal activities by both injection and feeding routes. These results indicate that Cp-TSP13 is a viral HTIF.
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Affiliation(s)
- Eunseong Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
| | - Yonggyun Kim
- Department of Bioresource Sciences, Andong National University, Andong 36729, Republic of Korea
- * E-mail:
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50
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Alavi M, Song M, King GLA, Gillis T, Propst R, Lamanuzzi M, Bousum A, Miller A, Allen R, Kidd T. Dscam1 Forms a Complex with Robo1 and the N-Terminal Fragment of Slit to Promote the Growth of Longitudinal Axons. PLoS Biol 2016; 14:e1002560. [PMID: 27654876 PMCID: PMC5031454 DOI: 10.1371/journal.pbio.1002560] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 08/23/2016] [Indexed: 11/19/2022] Open
Abstract
The Slit protein is a major midline repellent for central nervous system (CNS) axons. In vivo, Slit is proteolytically cleaved into N- and C-terminal fragments, but the biological significance of this is unknown. Analysis in the Drosophila ventral nerve cord of a slit allele (slit-UC) that cannot be cleaved revealed that midline repulsion is still present but longitudinal axon guidance is disrupted, particularly across segment boundaries. Double mutants for the Slit receptors Dscam1 and robo1 strongly resemble the slit-UC phenotype, suggesting they cooperate in longitudinal axon guidance, and through biochemical approaches, we found that Dscam1 and Robo1 form a complex dependent on Slit-N. In contrast, Robo1 binding alone shows a preference for full-length Slit, whereas Dscam1 only binds Slit-N. Using a variety of transgenes, we demonstrated that Dscam1 appears to modify the output of Robo/Slit complexes so that signaling is no longer repulsive. Our data suggest that the complex is promoting longitudinal axon growth across the segment boundary. The ability of Dscam1 to modify the output of other receptors in a ligand-dependent fashion may be a general principle for Dscam proteins.
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Affiliation(s)
- Maryam Alavi
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Minmin Song
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | | | - Taylor Gillis
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Robert Propst
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Matthew Lamanuzzi
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Adam Bousum
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Amanda Miller
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Ryan Allen
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
| | - Thomas Kidd
- Department of Biology, University of Nevada, Reno, Nevada, United States of America
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