1
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Xu C, Li Z, Lyu C, Hu Y, McLaughlin CN, Wong KKL, Xie Q, Luginbuhl DJ, Li H, Udeshi ND, Svinkina T, Mani DR, Han S, Li T, Li Y, Guajardo R, Ting AY, Carr SA, Li J, Luo L. Molecular and cellular mechanisms of teneurin signaling in synaptic partner matching. Cell 2024:S0092-8674(24)00696-2. [PMID: 38996528 DOI: 10.1016/j.cell.2024.06.022] [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: 02/11/2024] [Revised: 05/20/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024]
Abstract
In developing brains, axons exhibit remarkable precision in selecting synaptic partners among many non-partner cells. Evolutionarily conserved teneurins are transmembrane proteins that instruct synaptic partner matching. However, how intracellular signaling pathways execute teneurins' functions is unclear. Here, we use in situ proximity labeling to obtain the intracellular interactome of a teneurin (Ten-m) in the Drosophila brain. Genetic interaction studies using quantitative partner matching assays in both olfactory receptor neurons (ORNs) and projection neurons (PNs) reveal a common pathway: Ten-m binds to and negatively regulates a RhoGAP, thus activating the Rac1 small GTPases to promote synaptic partner matching. Developmental analyses with single-axon resolution identify the cellular mechanism of synaptic partner matching: Ten-m signaling promotes local F-actin levels and stabilizes ORN axon branches that contact partner PN dendrites. Combining spatial proteomics and high-resolution phenotypic analyses, this study advanced our understanding of both cellular and molecular mechanisms of synaptic partner matching.
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Affiliation(s)
- Chuanyun Xu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Zhuoran Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Cheng Lyu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Yixin Hu
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Colleen N McLaughlin
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Kenneth Kin Lam Wong
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Qijing Xie
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Neurosciences Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - David J Luginbuhl
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Hongjie Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Namrata D Udeshi
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tanya Svinkina
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - D R Mani
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Shuo Han
- Departments of Genetics, Biology, and Chemistry, Chan Zuckerberg Biohub, Stanford University, Stanford, CA 94305, USA
| | - Tongchao Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Yang Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA
| | - Ricardo Guajardo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Alice Y Ting
- Departments of Genetics, Biology, and Chemistry, Chan Zuckerberg Biohub, Stanford University, Stanford, CA 94305, USA
| | - Steven A Carr
- The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jiefu Li
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Biology Graduate Program, Stanford University, Stanford, CA 94305, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
| | - Liqun Luo
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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2
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Wang C, Zhang K, Cai B, Haller JE, Carnazza KE, Hu J, Zhao C, Tian Z, Hu X, Hall D, Qiang J, Hou S, Liu Z, Gu J, Zhang Y, Seroogy KB, Burré J, Fang Y, Liu C, Brunger AT, Li D, Diao J. VAMP2 chaperones α-synuclein in synaptic vesicle co-condensates. Nat Cell Biol 2024:10.1038/s41556-024-01456-1. [PMID: 38951706 DOI: 10.1038/s41556-024-01456-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 06/05/2024] [Indexed: 07/03/2024]
Abstract
α-Synuclein (α-Syn) aggregation is closely associated with Parkinson's disease neuropathology. Physiologically, α-Syn promotes synaptic vesicle (SV) clustering and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly. However, the underlying structural and molecular mechanisms are uncertain and it is not known whether this function affects the pathological aggregation of α-Syn. Here we show that the juxtamembrane region of vesicle-associated membrane protein 2 (VAMP2)-a component of the SNARE complex that resides on SVs-directly interacts with the carboxy-terminal region of α-Syn through charged residues to regulate α-Syn's function in clustering SVs and promoting SNARE complex assembly by inducing a multi-component condensed phase of SVs, α-Syn and other components. Moreover, VAMP2 binding protects α-Syn against forming aggregation-prone oligomers and fibrils in these condensates. Our results suggest a molecular mechanism that maintains α-Syn's function and prevents its pathological amyloid aggregation, the failure of which may lead to Parkinson's disease.
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Affiliation(s)
- Chuchu Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
- University of Chinese Academy of Sciences, Beijing, China
| | - Kai Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bin Cai
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jillian E Haller
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Kathryn E Carnazza
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Jiaojiao Hu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chunyu Zhao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhiqi Tian
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Xiao Hu
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Daniel Hall
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jiali Qiang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shouqiao Hou
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhenying Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jinge Gu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yaoyang Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Kim B Seroogy
- Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jacqueline Burré
- Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Cong Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Dan Li
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China.
- Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, China.
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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3
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Hofbauer B, Zandawala M, Reinhard N, Rieger D, Werner C, Evers JF, Wegener C. The neuropeptide pigment-dispersing factor signals independently of Bruchpilot-labelled active zones in daily remodelled terminals of Drosophila clock neurons. Eur J Neurosci 2024; 59:2665-2685. [PMID: 38414155 DOI: 10.1111/ejn.16294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/29/2024]
Abstract
The small ventrolateral neurons (sLNvs) are key components of the central clock in the Drosophila brain. They signal via the neuropeptide pigment-dispersing factor (PDF) to align the molecular clockwork of different central clock neurons and to modulate downstream circuits. The dorsal terminals of the sLNvs undergo daily morphological changes that affect presynaptic sites organised by the active zone protein Bruchpilot (BRP), a homolog of mammalian ELKS proteins. However, the role of these presynaptic sites for PDF release is ill-defined. Here, we combined expansion microscopy with labelling of active zones by endogenously tagged BRP to examine the spatial correlation between PDF-containing dense-core vesicles and BRP-labelled active zones. We found that the number of BRP-labelled puncta in the sLNv terminals was similar while their density differed between Zeitgeber time (ZT) 2 and 14. The relative distance between BRP- and PDF-labelled puncta was increased in the morning, around the reported time of PDF release. Spontaneous dense-core vesicle release profiles of sLNvs in a publicly available ssTEM dataset (FAFB) consistently lacked spatial correlation to BRP-organised active zones. RNAi-mediated downregulation of brp and other active zone proteins expressed by the sLNvs did not affect PDF-dependent locomotor rhythmicity. In contrast, down-regulation of genes encoding proteins of the canonical vesicle release machinery, the dense-core vesicle-related protein CADPS, as well as PDF impaired locomotor rhythmicity. Taken together, our study suggests that PDF release from the sLNvs is independent of BRP-organised active zones, while BRP may be redistributed to active zones in a time-dependent manner.
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Affiliation(s)
- Benedikt Hofbauer
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Meet Zandawala
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
- Department of Biochemistry and Molecular Biology, University of Nevada Reno, Reno, NV, USA
| | - Nils Reinhard
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Dirk Rieger
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Christian Werner
- Biocenter, Theodor-Boveri-Institute, Department of Biotechnology and Biophysics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Jan Felix Evers
- Centre for organismal studies COS, Universität Heidelberg, Heidelberg, Germany
- Cairn GmbH, Heidelberg, Germany
| | - Christian Wegener
- Biocenter, Theodor-Boveri-Institute, Neurobiology and Genetics, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
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4
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Iwanaga R, Yahagi N, Hakeda-Suzuki S, Suzuki T. Cell adhesion and actin dynamics factors promote axonal extension and synapse formation in transplanted Drosophila photoreceptor cells. Dev Growth Differ 2024; 66:205-218. [PMID: 38403285 DOI: 10.1111/dgd.12916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/27/2024]
Abstract
Vision is formed by the transmission of light stimuli to the brain through axons extending from photoreceptor cells. Damage to these axons leads to loss of vision. Despite research on neural circuit regeneration through transplantation, achieving precise axon projection remains challenging. To achieve optic nerve regeneration by transplantation, we employed the Drosophila visual system. We previously established a transplantation method for Drosophila utilizing photoreceptor precursor cells extracted from the eye disc. However, little axonal elongation of transplanted cells into the brain, the lamina, was observed. We verified axonal elongation to the lamina by modifying the selection process for transplanted cells. Moreover, we focused on N-cadherin (Ncad), a cell adhesion factor, and Twinstar (Tsr), which has been shown to promote actin reorganization and induce axon elongation in damaged nerves. Overexpression of Ncad and tsr promoted axon elongation to the lamina, along with presynaptic structure formation in the elongating axons. Furthermore, overexpression of Neurexin-1 (Nrx-1), encoding a protein identified as a synaptic organizer, was found to not only promote presynapse formation but also enhance axon elongation. By introducing Ncad, tsr, and Nrx-1, we not only successfully achieved axonal projection of transplanted cells to the brain beyond the retina, but also confirmed the projection of transplanted cells into a deeper ganglion, the medulla. The present study offers valuable insights to realize regeneration through transplantation in a more complex nervous system.
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Affiliation(s)
- Riku Iwanaga
- School of Life Science and Technology, Tokyo Institute of Technology, Yokahama, Japan
| | - Nagisa Yahagi
- School of Life Science and Technology, Tokyo Institute of Technology, Yokahama, Japan
| | - Satoko Hakeda-Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, Yokahama, Japan
- Research Initiatives and Promotion Organization, Yokohama National University, Yokohama, Japan
| | - Takashi Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, Yokahama, Japan
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5
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Weiss JT, Blundell MZ, Singh P, Donlea JM. Sleep deprivation drives brain-wide changes in cholinergic presynapse abundance in Drosophila melanogaster. Proc Natl Acad Sci U S A 2024; 121:e2312664121. [PMID: 38498719 PMCID: PMC10990117 DOI: 10.1073/pnas.2312664121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024] Open
Abstract
Sleep is an evolutionarily conserved state that supports brain functions, including synaptic plasticity, in species across the animal kingdom. Here, we examine the neuroanatomical and cell-type distribution of presynaptic scaling in the fly brain after sleep loss. We previously found that sleep loss drives accumulation of the active zone scaffolding protein Bruchpilot (BRP) within cholinergic Kenyon cells of the Drosophila melanogaster mushroom body (MB), but not in other classes of MB neurons. To test whether similar cell type-specific trends in plasticity occur broadly across the brain, we used a flp-based genetic reporter to label presynaptic BRP in cholinergic, dopaminergic, GABAergic, or glutamatergic neurons. We then collected whole-brain confocal image stacks of BRP intensity to systematically quantify BRP, a marker of presynapse abundance, across 37 neuropil regions of the central fly brain. Our results indicate that sleep loss, either by overnight (12-h) mechanical stimulation or chronic sleep disruption in insomniac mutants, broadly elevates cholinergic synapse abundance across the brain, while synapse abundance in neurons that produce other neurotransmitters undergoes weaker, if any, changes. Extending sleep deprivation to 24 h drives brain-wide upscaling in glutamatergic, but not other, synapses. Finally, overnight male-male social pairings induce increased BRP in excitatory synapses despite male-female pairings eliciting more waking activity, suggesting experience-specific plasticity. Within neurotransmitter class and waking context, BRP changes are similar across the 37 neuropil domains, indicating that similar synaptic scaling rules may apply across the brain during acute sleep loss and that sleep need may broadly alter excitatory-inhibitory balance in the central brain.
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Affiliation(s)
- Jacqueline T. Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
- Neuroscience Interdepartmental Program, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Mei Z. Blundell
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
| | - Prabhjit Singh
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
| | - Jeffrey M. Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, CA90095
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6
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Sanfilippo P, Kim AJ, Bhukel A, Yoo J, Mirshahidi PS, Pandey V, Bevir H, Yuen A, Mirshahidi PS, Guo P, Li HS, Wohlschlegel JA, Aso Y, Zipursky SL. Mapping of multiple neurotransmitter receptor subtypes and distinct protein complexes to the connectome. Neuron 2024; 112:942-958.e13. [PMID: 38262414 PMCID: PMC10957333 DOI: 10.1016/j.neuron.2023.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/03/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024]
Abstract
Neurons express various combinations of neurotransmitter receptor (NR) subunits and receive inputs from multiple neuron types expressing different neurotransmitters. Localizing NR subunits to specific synaptic inputs has been challenging. Here, we use epitope-tagged endogenous NR subunits, expansion light-sheet microscopy, and electron microscopy (EM) connectomics to molecularly characterize synapses in Drosophila. We show that in directionally selective motion-sensitive neurons, different multiple NRs elaborated a highly stereotyped molecular topography with NR localized to specific domains receiving cell-type-specific inputs. Developmental studies suggested that NRs or complexes of them with other membrane proteins determine patterns of synaptic inputs. In support of this model, we identify a transmembrane protein selectively associated with a subset of spatially restricted synapses and demonstrate its requirement for synapse formation through genetic analysis. We propose that mechanisms that regulate the precise spatial distribution of NRs provide a molecular cartography specifying the patterns of synaptic connections onto dendrites.
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Affiliation(s)
- Piero Sanfilippo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander J Kim
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Anuradha Bhukel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Juyoun Yoo
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Pegah S Mirshahidi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Vijaya Pandey
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Harry Bevir
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ashley Yuen
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Parmis S Mirshahidi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Peiyi Guo
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Hong-Sheng Li
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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7
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Osaka J, Ishii A, Wang X, Iwanaga R, Kawamura H, Akino S, Sugie A, Hakeda-Suzuki S, Suzuki T. Complex formation of immunoglobulin superfamily molecules Side-IV and Beat-IIb regulates synaptic specificity. Cell Rep 2024; 43:113798. [PMID: 38381608 DOI: 10.1016/j.celrep.2024.113798] [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: 06/29/2023] [Revised: 08/03/2023] [Accepted: 01/31/2024] [Indexed: 02/23/2024] Open
Abstract
Neurons establish specific synapses based on the adhesive properties of cell-surface proteins while also retaining the ability to form synapses in a relatively non-selective manner. However, comprehensive understanding of the underlying mechanism reconciling these opposing characteristics remains incomplete. Here, we have identified Side-IV/Beat-IIb, members of the Drosophila immunoglobulin superfamily, as a combination of cell-surface recognition molecules inducing synapse formation. The Side-IV/Beat-IIb combination transduces bifurcated signaling with Side-IV's co-receptor, Kirre, and a synaptic scaffold protein, Dsyd-1. Genetic experiments and subcellular protein localization analyses showed the Side-IV/Beat-IIb/Kirre/Dsyd-1 complex to have two essential functions. First, it narrows neuronal binding specificity through Side-IV/Beat-IIb extracellular interactions. Second, it recruits synapse formation factors, Kirre and Dsyd-1, to restrict synaptic loci and inhibit miswiring. This dual function explains how the combinations of cell-surface molecules enable the ranking of preferred interactions among neuronal pairs to achieve synaptic specificity in complex circuits in vivo.
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Affiliation(s)
- Jiro Osaka
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan; Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Arisa Ishii
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Xu Wang
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Riku Iwanaga
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hinata Kawamura
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Shogo Akino
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Atsushi Sugie
- Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Satoko Hakeda-Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan; Research Initiatives and Promotion Organization, Yokohama National University, Yokohama 240-8501, Japan
| | - Takashi Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
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8
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Xu C, Ramos TB, Marshall OJ, Doe CQ. Notch signaling and Bsh homeodomain activity are integrated to diversify Drosophila lamina neuron types. eLife 2024; 12:RP90136. [PMID: 38193901 PMCID: PMC10945509 DOI: 10.7554/elife.90136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
Notch signaling is an evolutionarily conserved pathway for specifying binary neuronal fates, yet how it specifies different fates in different contexts remains elusive. In our accompanying paper, using the Drosophila lamina neuron types (L1-L5) as a model, we show that the primary homeodomain transcription factor (HDTF) Bsh activates secondary HDTFs Ap (L4) and Pdm3 (L5) and specifies L4/L5 neuronal fates. Here we test the hypothesis that Notch signaling enables Bsh to differentially specify L4 and L5 fates. We show asymmetric Notch signaling between newborn L4 and L5 neurons, but they are not siblings; rather, Notch signaling in L4 is due to Delta expression in adjacent L1 neurons. While Notch signaling and Bsh expression are mutually independent, Notch is necessary and sufficient for Bsh to specify L4 fate over L5. The NotchON L4, compared to NotchOFF L5, has a distinct open chromatin landscape which allows Bsh to bind distinct genomic loci, leading to L4-specific identity gene transcription. We propose a novel model in which Notch signaling is integrated with the primary HDTF activity to diversify neuron types by directly or indirectly generating a distinct open chromatin landscape that constrains the pool of genes that a primary HDTF can activate.
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Affiliation(s)
- Chundi Xu
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Tyler B Ramos
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Owen J Marshall
- Menzies Institute for Medical Research, University of TasmaniaHobartAustralia
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
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9
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Xu C, Ramos TB, Rogers EM, Reiser MB, Doe CQ. Homeodomain proteins hierarchically specify neuronal diversity and synaptic connectivity. eLife 2024; 12:RP90133. [PMID: 38180023 PMCID: PMC10942767 DOI: 10.7554/elife.90133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024] Open
Abstract
How our brain generates diverse neuron types that assemble into precise neural circuits remains unclear. Using Drosophila lamina neuron types (L1-L5), we show that the primary homeodomain transcription factor (HDTF) brain-specific homeobox (Bsh) is initiated in progenitors and maintained in L4/L5 neurons to adulthood. Bsh activates secondary HDTFs Ap (L4) and Pdm3 (L5) and specifies L4/L5 neuronal fates while repressing the HDTF Zfh1 to prevent ectopic L1/L3 fates (control: L1-L5; Bsh-knockdown: L1-L3), thereby generating lamina neuronal diversity for normal visual sensitivity. Subsequently, in L4 neurons, Bsh and Ap function in a feed-forward loop to activate the synapse recognition molecule DIP-β, thereby bridging neuronal fate decision to synaptic connectivity. Expression of a Bsh:Dam, specifically in L4, reveals Bsh binding to the DIP-β locus and additional candidate L4 functional identity genes. We propose that HDTFs function hierarchically to coordinate neuronal molecular identity, circuit formation, and function. Hierarchical HDTFs may represent a conserved mechanism for linking neuronal diversity to circuit assembly and function.
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Affiliation(s)
- Chundi Xu
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Tyler B Ramos
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
| | - Edward M Rogers
- Janelia Research Campus, Howard Hughes Medical Institute, Helix DriveAshburnUnited States
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, Helix DriveAshburnUnited States
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of OregonEugeneUnited States
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10
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Aimino MA, Humenik J, Parisi MJ, Duhart JC, Mosca TJ. SynLight: a bicistronic strategy for simultaneous active zone and cell labeling in the Drosophila nervous system. G3 (BETHESDA, MD.) 2023; 13:jkad221. [PMID: 37757863 PMCID: PMC10627267 DOI: 10.1093/g3journal/jkad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/14/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023]
Abstract
At synapses, chemical neurotransmission mediates the exchange of information between neurons, leading to complex movement, behaviors, and stimulus processing. The immense number and variety of neurons within the nervous system make discerning individual neuron populations difficult, necessitating the development of advanced neuronal labeling techniques. In Drosophila, Bruchpilot-Short and mCD8-GFP, which label presynaptic active zones and neuronal membranes, respectively, have been widely used to study synapse development and organization. This labeling is often achieved via the expression of 2 independent constructs by a single binary expression system, but expression can weaken when multiple transgenes are expressed by a single driver. Recent work has sought to circumvent these drawbacks by developing methods that encode multiple proteins from a single transcript. Self-cleaving peptides, specifically 2A peptides, have emerged as effective sequences for accomplishing this task. We leveraged 2A ribosomal skipping peptides to engineer a construct that produces both Bruchpilot-Short-mStraw and mCD8-GFP from the same mRNA, which we named SynLight. Using SynLight, we visualized the putative synaptic active zones and membranes of multiple classes of olfactory, visual, and motor neurons and observed the correct separation of signal, confirming that both proteins are being generated separately. Furthermore, we demonstrate proof of principle by quantifying synaptic puncta number and neurite volume in olfactory neurons and finding no difference between the synapse densities of neurons expressing SynLight or neurons expressing both transgenes separately. At the neuromuscular junction, we determined that the synaptic puncta number labeled by SynLight was comparable to the endogenous puncta labeled by antibody staining. Overall, SynLight is a versatile tool for examining synapse density in any nervous system region of interest and allows new questions to be answered about synaptic development and organization.
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Affiliation(s)
- Michael A Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Jesse Humenik
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael J Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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11
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Sanfilippo P, Kim AJ, Bhukel A, Yoo J, Mirshahidi PS, Pandey V, Bevir H, Yuen A, Mirshahidi PS, Guo P, Li HS, Wohlschlegel JA, Aso Y, Zipursky SL. Mapping of multiple neurotransmitter receptor subtypes and distinct protein complexes to the connectome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560011. [PMID: 37873314 PMCID: PMC10592863 DOI: 10.1101/2023.10.02.560011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Neurons express different combinations of neurotransmitter receptor (NR) subunits and receive inputs from multiple neuron types expressing different neurotransmitters. Localizing NR subunits to specific synaptic inputs has been challenging. Here we use epitope tagged endogenous NR subunits, expansion light-sheet microscopy, and EM connectomics to molecularly characterize synapses in Drosophila. We show that in directionally selective motion sensitive neurons, different multiple NRs elaborated a highly stereotyped molecular topography with NR localized to specific domains receiving cell-type specific inputs. Developmental studies suggested that NRs or complexes of them with other membrane proteins determines patterns of synaptic inputs. In support of this model, we identify a transmembrane protein associated selectively with a subset of spatially restricted synapses and demonstrate through genetic analysis its requirement for synapse formation. We propose that mechanisms which regulate the precise spatial distribution of NRs provide a molecular cartography specifying the patterns of synaptic connections onto dendrites.
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Affiliation(s)
- Piero Sanfilippo
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
- Howard Hughes Medical Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Alexander J Kim
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Anuradha Bhukel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Juyoun Yoo
- Neuroscience Interdepartmental Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Pegah S Mirshahidi
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Vijaya Pandey
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Harry Bevir
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Ashley Yuen
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Parmis S Mirshahidi
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Peiyi Guo
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Hong-Sheng Li
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
- Howard Hughes Medical Institute, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Lead Contact
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12
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Salzberg Y, Haque R, Oren-Suissa M. The synaptic basis for sexual dimorphism in the invertebrate nervous system. Curr Opin Neurobiol 2023; 82:102757. [PMID: 37572555 PMCID: PMC10506627 DOI: 10.1016/j.conb.2023.102757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 08/14/2023]
Abstract
Many animal behaviors are manifested differently in the two sexes of a given species, but how such sexual dimorphism is imprinted in the nervous system is not always clear. One mechanism involved is synaptic dimorphism, by which the same neurons exist in the two sexes, but form synapses that differ in features such as anatomy, molecular content or fate. While some evidence for synaptic dimorphism exists in humans and mammals, identifying these mechanisms in invertebrates has proven simpler, due to their smaller nervous systems and absence of external regulation by sex hormones. This review aims to present the current status of the field in invertebrates, the available toolkit for the study of synaptic dimorphism, and the standing questions that still remain incompletely answered.
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Affiliation(s)
- Yehuda Salzberg
- Department of Brain Science, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Rizwanul Haque
- Department of Brain Science, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Meital Oren-Suissa
- Department of Brain Science, Weizmann Institute of Science, Rehovot, 7610001, Israel.
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13
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Yoo J, Dombrovski M, Mirshahidi P, Nern A, LoCascio SA, Zipursky SL, Kurmangaliyev YZ. Brain wiring determinants uncovered by integrating connectomes and transcriptomes. Curr Biol 2023; 33:3998-4005.e6. [PMID: 37647901 DOI: 10.1016/j.cub.2023.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/12/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023]
Abstract
Advances in brain connectomics have demonstrated the extraordinary complexity of neural circuits.1,2,3,4,5 Developing neurons encounter the axons and dendrites of many different neuron types and form synapses with only a subset of them. During circuit assembly, neurons express cell-type-specific repertoires comprising many cell adhesion molecules (CAMs) that can mediate interactions between developing neurites.6,7,8 Many CAM families have been shown to contribute to brain wiring in different ways.9,10 It has been challenging, however, to identify receptor-ligand pairs directly matching neurons with their synaptic targets. Here, we integrated the synapse-level connectome of the neural circuit11,12 with the developmental expression patterns7 and binding specificities of CAMs6,13 on pre- and postsynaptic neurons in the Drosophila visual system. To overcome the complexity of neural circuits, we focus on pairs of genetically related neurons that make differential wiring choices. In the motion detection circuit,14 closely related subtypes of T4/T5 neurons choose between alternative synaptic targets in adjacent layers of neuropil.12 This choice correlates with the matching expression in synaptic partners of different receptor-ligand pairs of the Beat and Side families of CAMs. Genetic analysis demonstrated that presynaptic Side-II and postsynaptic Beat-VI restrict synaptic partners to the same layer. Removal of this receptor-ligand pair disrupts layers and leads to inappropriate targeting of presynaptic sites and postsynaptic dendrites. We propose that different Side/Beat receptor-ligand pairs collaborate with other recognition molecules to determine wiring specificities in the fly brain. Combining transcriptomes, connectomes, and protein interactome maps allow unbiased identification of determinants of brain wiring.
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Affiliation(s)
- Juyoun Yoo
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Mark Dombrovski
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Parmis Mirshahidi
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Samuel A LoCascio
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Yerbol Z Kurmangaliyev
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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14
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Poe AR, Zhu L, Szuperak M, McClanahan PD, Anafi RC, Scholl B, Thum AS, Cavanaugh DJ, Kayser MS. Developmental emergence of sleep rhythms enables long-term memory in Drosophila. SCIENCE ADVANCES 2023; 9:eadh2301. [PMID: 37683005 PMCID: PMC10491288 DOI: 10.1126/sciadv.adh2301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/09/2023] [Indexed: 09/10/2023]
Abstract
In adulthood, sleep-wake rhythms are one of the most prominent behaviors under circadian control. However, during early life, sleep is spread across the 24-hour day. The mechanism through which sleep rhythms emerge, and consequent advantage conferred to a juvenile animal, is unknown. In the second-instar Drosophila larvae (L2), like in human infants, sleep is not under circadian control. We identify the precise developmental time point when the clock begins to regulate sleep in Drosophila, leading to emergence of sleep rhythms in early third-instars (L3). At this stage, a cellular connection forms between DN1a clock neurons and arousal-promoting Dh44 neurons, bringing arousal under clock control to drive emergence of circadian sleep. Last, we demonstrate that L3 but not L2 larvae exhibit long-term memory (LTM) of aversive cues and that this LTM depends upon deep sleep generated once sleep rhythms begin. We propose that the developmental emergence of circadian sleep enables more complex cognitive processes, including the onset of enduring memories.
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Affiliation(s)
- Amy R. Poe
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lucy Zhu
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Milan Szuperak
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Ron C. Anafi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Benjamin Scholl
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andreas S. Thum
- Department of Genetics, Institute of Biology, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
| | | | - Matthew S. Kayser
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Gundermann DG, Lymer S, Blau J. A rapid and dynamic role for FMRP in the plasticity of adult neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555985. [PMID: 37693612 PMCID: PMC10491314 DOI: 10.1101/2023.09.01.555985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Fragile X syndrome (FXS) is a neuro-developmental disorder caused by silencing Fmr1, which encodes the RNA-binding protein FMRP. Although Fmr1 is expressed in adult neurons, it has been challenging to separate acute from chronic effects of loss of Fmr1 in models of FXS. We have used the precision of Drosophila genetics to test if Fmr1 acutely affects adult neuronal plasticity in vivo, focusing on the s-LNv circadian pacemaker neurons that show 24 hour rhythms in structural plasticity. We found that over-expressing Fmr1 for only 4 hours blocks the activity-dependent expansion of s-LNv projections without altering the circadian clock or activity-regulated gene expression. Conversely, acutely reducing Fmr1 expression prevented s-LNv projections from retracting. One FMRP target that we identified in s-LNvs is sif, which encodes a Rac1 GEF. Our data indicate that FMRP normally reduces sif mRNA translation at dusk to reduce Rac1 activity. Overall, our data reveal a previously unappreciated rapid and direct role for FMRP in acutely regulating neuronal plasticity in adult neurons, and underscore the importance of RNA-binding proteins in this process.
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Affiliation(s)
- Daniel G Gundermann
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - Seana Lymer
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
- Current address: Proteintech Genomics, 11588 Sorrento Valley Rd, San Diego, CA 92121
| | - Justin Blau
- Department of Biology, New York University, 100 Washington Square East, New York, NY 10003, USA
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Abu Dhabi, UAE
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16
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Singh P, Aleman A, Omoto JJ, Nguyen BC, Kandimalla P, Hartenstein V, Donlea JM. Examining Sleep Modulation by Drosophila Ellipsoid Body Neurons. eNeuro 2023; 10:ENEURO.0281-23.2023. [PMID: 37679041 PMCID: PMC10523840 DOI: 10.1523/eneuro.0281-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 08/10/2023] [Indexed: 09/09/2023] Open
Abstract
Recent work in Drosophila has uncovered several neighboring classes of sleep-regulatory neurons within the central complex. However, the logic of connectivity and network motifs remains limited by the incomplete examination of relevant cell types. Using a recent genetic-anatomic classification of ellipsoid body ring neurons, we conducted a thermogenetic screen in female flies to assess sleep/wake behavior and identified two wake-promoting drivers that label ER3d neurons and two sleep-promoting drivers that express in ER3m cells. We then used intersectional genetics to refine driver expression patterns. Activation of ER3d cells shortened sleep bouts, suggesting a key role in sleep maintenance. While sleep-promoting drivers from our mini-screen label overlapping ER3m neurons, intersectional strategies cannot rule out sleep regulatory roles for additional neurons in their expression patterns. Suppressing GABA synthesis in ER3m neurons prevents postinjury sleep, and GABAergic ER3d cells are required for thermogenetically induced wakefulness. Finally, we use an activity-dependent fluorescent reporter for putative synaptic contacts to embed these neurons within the known sleep-regulatory network. ER3m and ER3d neurons may receive connections from wake-active Helicon/ExR1 cells, and ER3m neurons likely inhibit ER3d neurons. Together, these data suggest a neural mechanism by which previously uncharacterized circuit elements stabilize sleep-wake states.
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Affiliation(s)
- Prabhjit Singh
- Department of Neurobiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
| | - Abigail Aleman
- Department of Neurobiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
- Molecular, Cellular & Integrative Physiology Interdepartmental Program, University of California-Los Angeles, Los Angeles, California 90095
| | - Jaison Jiro Omoto
- Department of Neurobiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
| | - Bao-Chau Nguyen
- Department of Molecular, Cell, & Developmental Biology, University of California-Los Angeles, Los Angeles, California 90095
| | - Pratyush Kandimalla
- Department of Molecular, Cell, & Developmental Biology, University of California-Los Angeles, Los Angeles, California 90095
| | - Volker Hartenstein
- Department of Molecular, Cell, & Developmental Biology, University of California-Los Angeles, Los Angeles, California 90095
| | - Jeffrey M Donlea
- Department of Neurobiology, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California 90095
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17
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Aimino MA, Humenik J, Parisi MJ, Duhart JC, Mosca TJ. SynLight: a dicistronic strategy for simultaneous active zone and cell labeling in the Drosophila nervous system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549367. [PMID: 37502901 PMCID: PMC10370149 DOI: 10.1101/2023.07.17.549367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
At synapses, chemical neurotransmission mediates the exchange of information between neurons, leading to complex movement behaviors and stimulus processing. The immense number and variety of neurons within the nervous system makes discerning individual neuron populations difficult, necessitating the development of advanced neuronal labeling techniques. In Drosophila , Bruchpilot-Short and mCD8-GFP, which label presynaptic active zones and neuronal membranes, respectively, have been widely used to study synapse development and organization. This labeling is often achieved via expression of two independent constructs by a single binary expression system, but expression can weaken when multiple transgenes are expressed by a single driver. Ensuring adequate expression of each transgene is essential to enable more complex experiments; as such, work has sought to circumvent these drawbacks by developing methods that encode multiple proteins from a single transcript. Self-cleaving peptides, specifically 2A peptides, have emerged as effective sequences for accomplishing this task. We leveraged 2A ribosomal skipping peptides to engineer a construct that produces both Bruchpilot-Short and mCD8-GFP from the same mRNA, which we named SynLight. Using SynLight, we visualized the putative synaptic active zones and membranes of multiple classes of olfactory, visual, and motor neurons and observed correct separation of signal, confirming that both proteins are being generated separately. Furthermore, we demonstrate proof-of-principle by quantifying synaptic puncta number and neurite volume in olfactory neurons and finding no difference between the synapse densities of neurons expressing SynLight or neurons expressing both transgenes separately. At the neuromuscular junction, we determined that synaptic puncta number labeled by SynLight was comparable to endogenous puncta labeled by antibody staining. Overall, SynLight is a versatile tool for examining synapse density in any nervous system region of interest and allows new questions to be answered about synaptic development and organization.
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Affiliation(s)
- Michael A. Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Jesse Humenik
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Michael J. Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
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18
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Bonanno SL, Krantz DE. Transcriptional changes in specific subsets of Drosophila neurons following inhibition of the serotonin transporter. Transl Psychiatry 2023; 13:226. [PMID: 37355701 DOI: 10.1038/s41398-023-02521-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 06/06/2023] [Accepted: 06/13/2023] [Indexed: 06/26/2023] Open
Abstract
The transcriptional effects of SSRIs and other serotonergic drugs remain unclear, in part due to the heterogeneity of postsynaptic cells, which may respond differently to changes in serotonergic signaling. Relatively simple model systems such as Drosophila afford more tractable microcircuits in which to investigate these changes in specific cell types. Here, we focus on the mushroom body, an insect brain structure heavily innervated by serotonin and comprised of multiple different but related subtypes of Kenyon cells. We use fluorescence-activated cell sorting of Kenyon cells, followed by either bulk or single-cell RNA sequencing to explore the transcriptomic response of these cells to SERT inhibition. We compared the effects of two different Drosophila Serotonin Transporter (dSERT) mutant alleles as well as feeding the SSRI citalopram to adult flies. We find that the genetic architecture associated with one of the mutants contributed to significant artefactual changes in expression. Comparison of differential expression caused by loss of SERT during development versus aged, adult flies, suggests that changes in serotonergic signaling may have relatively stronger effects during development, consistent with behavioral studies in mice. Overall, our experiments revealed limited transcriptomic changes in Kenyon cells, but suggest that different subtypes may respond differently to SERT loss-of-function. Further work exploring the effects of SERT loss-of-function in other circuits may be used help to elucidate how SSRIs differentially affect a variety of different neuronal subtypes both during development and in adults.
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Affiliation(s)
- Shivan L Bonanno
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
| | - David E Krantz
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
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19
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Ji H, Wang B, Shen Y, Labib D, Lei J, Chen X, Sapar M, Boulanger A, Dura JM, Han C. The Drosophila chemokine-like Orion bridges phosphatidylserine and Draper in phagocytosis of neurons. Proc Natl Acad Sci U S A 2023; 120:e2303392120. [PMID: 37276397 PMCID: PMC10268242 DOI: 10.1073/pnas.2303392120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/10/2023] [Indexed: 06/07/2023] Open
Abstract
Phagocytic clearance of degenerating neurons is triggered by "eat-me" signals exposed on the neuronal surface. The conserved neuronal eat-me signal phosphatidylserine (PS) and the engulfment receptor Draper (Drpr) mediate phagocytosis of degenerating neurons in Drosophila. However, how PS is recognized by Drpr-expressing phagocytes in vivo remains poorly understood. Using multiple models of dendrite degeneration, we show that the Drosophila chemokine-like protein Orion can bind to PS and is responsible for detecting PS exposure on neurons; it is supplied cell-non-autonomously to coat PS-exposing dendrites and to mediate interactions between PS and Drpr, thus enabling phagocytosis. As a result, the accumulation of Orion on neurons and on phagocytes produces opposite outcomes by potentiating and suppressing phagocytosis, respectively. Moreover, the Orion dosage is a key determinant of the sensitivity of phagocytes to PS exposed on neurons. Lastly, mutagenesis analyses show that the sequence motifs shared between Orion and human immunomodulatory proteins are important for Orion function. Thus, our results uncover a missing link in PS-mediated phagocytosis in Drosophila and imply conserved mechanisms of phagocytosis of neurons.
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Affiliation(s)
- Hui Ji
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Bei Wang
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Yifan Shen
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - David Labib
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Joyce Lei
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Xinchen Chen
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Maria Sapar
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
| | - Ana Boulanger
- Institute of Human Genetics (IGH), Univ Montpellier, CNRS, Montpellier34090, France
| | - Jean-Maurice Dura
- Institute of Human Genetics (IGH), Univ Montpellier, CNRS, Montpellier34090, France
| | - Chun Han
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY14853
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY14853
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20
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Parisi MJ, Aimino MA, Mosca TJ. A conditional strategy for cell-type-specific labeling of endogenous excitatory synapses in Drosophila. CELL REPORTS METHODS 2023; 3:100477. [PMID: 37323572 PMCID: PMC10261928 DOI: 10.1016/j.crmeth.2023.100477] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/28/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023]
Abstract
Chemical neurotransmission occurs at specialized contacts where neurotransmitter release machinery apposes neurotransmitter receptors to underlie circuit function. A series of complex events underlies pre- and postsynaptic protein recruitment to neuronal connections. To better study synaptic development in individual neurons, we need cell-type-specific strategies to visualize endogenous synaptic proteins. Although presynaptic strategies exist, postsynaptic proteins remain less studied because of a paucity of cell-type-specific reagents. To study excitatory postsynapses with cell-type specificity, we engineered dlg1[4K], a conditionally labeled marker of Drosophila excitatory postsynaptic densities. With binary expression systems, dlg1[4K] labels central and peripheral postsynapses in larvae and adults. Using dlg1[4K], we find that distinct rules govern postsynaptic organization in adult neurons, multiple binary expression systems can concurrently label pre- and postsynapse in a cell-type-specific manner, and neuronal DLG1 can sometimes localize presynaptically. These results validate our strategy for conditional postsynaptic labeling and demonstrate principles of synaptic organization.
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Affiliation(s)
- Michael J. Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael A. Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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21
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Bonanno SL, Krantz DE. Transcriptional changes in specific subsets of Drosophila neurons following inhibition of the serotonin transporter. RESEARCH SQUARE 2023:rs.3.rs-2626506. [PMID: 36993644 PMCID: PMC10055553 DOI: 10.21203/rs.3.rs-2626506/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The transcriptional effects of SSRIs and other serotonergic drugs remain unclear, in part due to the heterogeneity of postsynaptic cells, which may respond differently to changes in serotonergic signaling. Relatively simple model systems such as Drosophila afford more tractable microcircuits in which to investigate these changes in specific cell types. Here, we focus on the mushroom body, an insect brain structure heavily innervated by serotonin and comprised of multiple different but related subtypes of Kenyon cells. We use fluorescence activated cell sorting of Kenyon cells, followed by either or bulk or single cell RNA sequencing to explore the transcriptomic response of these cells to SERT inhibition. We compared the effects of two different Drosophila Serotonin Transporter (dSERT) mutant alleles as well as feeding the SSRI citalapram to adult flies. We find that the genetic architecture associated with one of the mutants contributed to significant artefactual changes in expression. Comparison of differential expression caused by loss of SERT during development versus aged, adult flies, suggests that changes in serotonergic signaling may have relatively stronger effects during development, consistent with behavioral studies in mice. Overall, our experiments revealed limited transcriptomic changes in Kenyon cells, but suggest that different subtypes may respond differently to SERT loss-of-function. Further work exploring the effects of SERT loss-of-function in other Drosophila circuits may be used help to elucidate how SSRIs differentially affect a variety of different neuronal subtypes both during development and in adults.
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Affiliation(s)
- Shivan L. Bonanno
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - David E. Krantz
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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22
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Osaka J, Yasuda H, Watanuki Y, Kato Y, Nitta Y, Sugie A, Sato M, Suzuki T. Identification of genes regulating stimulus-dependent synaptic assembly in Drosophila using an automated synapse quantification system. Genes Genet Syst 2023; 97:297-309. [PMID: 36878557 DOI: 10.1266/ggs.22-00114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
Neural activity-dependent synaptic plasticity is an important physiological phenomenon underlying environmental adaptation, memory and learning. However, its molecular basis, especially in presynaptic neurons, is not well understood. Previous studies have shown that the number of presynaptic active zones in the Drosophila melanogaster photoreceptor R8 is reversibly changed in an activity-dependent manner. During reversible synaptic changes, both synaptic disassembly and assembly processes were observed. Although we have established a paradigm for screening molecules involved in synaptic stability and several genes have been identified, genes involved in stimulus-dependent synaptic assembly are still elusive. Therefore, the aim of this study was to identify genes regulating stimulus-dependent synaptic assembly in Drosophila using an automated synapse quantification system. To this end, we performed RNAi screening against 300 memory-defective, synapse-related or transmembrane molecules in photoreceptor R8 neurons. Candidate genes were narrowed down to 27 genes in the first screen using presynaptic protein aggregation as a sign of synaptic disassembly. In the second screen, we directly quantified the decreasing synapse number using a GFP-tagged presynaptic protein marker. We utilized custom-made image analysis software, which automatically locates synapses and counts their number along individual R8 axons, and identified cirl as a candidate gene responsible for synaptic assembly. Finally, we present a new model of stimulus-dependent synaptic assembly through the interaction of cirl and its possible ligand, ten-a. This study demonstrates the feasibility of using the automated synapse quantification system to explore activity-dependent synaptic plasticity in Drosophila R8 photoreceptors in order to identify molecules involved in stimulus-dependent synaptic assembly.
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Affiliation(s)
- Jiro Osaka
- School of Life Science and Technology, Tokyo Institute of Technology
| | - Haruka Yasuda
- School of Life Science and Technology, Tokyo Institute of Technology
| | - Yusuke Watanuki
- School of Life Science and Technology, Tokyo Institute of Technology
| | - Yuya Kato
- School of Life Science and Technology, Tokyo Institute of Technology
| | - Yohei Nitta
- Brain Research Institute, Niigata University
| | | | - Makoto Sato
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University.,Graduate School of Frontier Science Initiative, Kanazawa University
| | - Takashi Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology
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23
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Dombrovski M, Peek MY, Park JY, Vaccari A, Sumathipala M, Morrow C, Breads P, Zhao A, Kurmangaliyev YZ, Sanfilippo P, Rehan A, Polsky J, Alghailani S, Tenshaw E, Namiki S, Zipursky SL, Card GM. Synaptic gradients transform object location to action. Nature 2023; 613:534-542. [PMID: 36599984 PMCID: PMC9849133 DOI: 10.1038/s41586-022-05562-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 11/11/2022] [Indexed: 01/06/2023]
Abstract
To survive, animals must convert sensory information into appropriate behaviours1,2. Vision is a common sense for locating ethologically relevant stimuli and guiding motor responses3-5. How circuitry converts object location in retinal coordinates to movement direction in body coordinates remains largely unknown. Here we show through behaviour, physiology, anatomy and connectomics in Drosophila that visuomotor transformation occurs by conversion of topographic maps formed by the dendrites of feature-detecting visual projection neurons (VPNs)6,7 into synaptic weight gradients of VPN outputs onto central brain neurons. We demonstrate how this gradient motif transforms the anteroposterior location of a visual looming stimulus into the fly's directional escape. Specifically, we discover that two neurons postsynaptic to a looming-responsive VPN type promote opposite takeoff directions. Opposite synaptic weight gradients onto these neurons from looming VPNs in different visual field regions convert localized looming threats into correctly oriented escapes. For a second looming-responsive VPN type, we demonstrate graded responses along the dorsoventral axis. We show that this synaptic gradient motif generalizes across all 20 primary VPN cell types and most often arises without VPN axon topography. Synaptic gradients may thus be a general mechanism for conveying spatial features of sensory information into directed motor outputs.
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Affiliation(s)
- Mark Dombrovski
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Martin Y Peek
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jin-Yong Park
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Andrea Vaccari
- Department of Computer Science, Middlebury College, Middlebury, VT, USA
| | | | - Carmen Morrow
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Patrick Breads
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Arthur Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yerbol Z Kurmangaliyev
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Piero Sanfilippo
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Aadil Rehan
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jason Polsky
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Shada Alghailani
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Emily Tenshaw
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Shigehiro Namiki
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.,Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA. .,Department of Neuroscience, Howard Hughes Medical Institute, The Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
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24
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Liu Z, Zhu Y, Zhang L, Jiang W, Liu Y, Tang Q, Cai X, Li J, Wang L, Tao C, Yin X, Li X, Hou S, Jiang D, Liu K, Zhou X, Zhang H, Liu M, Fan C, Tian Y. Structural and functional imaging of brains. Sci China Chem 2022; 66:324-366. [PMID: 36536633 PMCID: PMC9753096 DOI: 10.1007/s11426-022-1408-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/28/2022] [Indexed: 12/23/2022]
Abstract
Analyzing the complex structures and functions of brain is the key issue to understanding the physiological and pathological processes. Although neuronal morphology and local distribution of neurons/blood vessels in the brain have been known, the subcellular structures of cells remain challenging, especially in the live brain. In addition, the complicated brain functions involve numerous functional molecules, but the concentrations, distributions and interactions of these molecules in the brain are still poorly understood. In this review, frontier techniques available for multiscale structure imaging from organelles to the whole brain are first overviewed, including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), serial-section electron microscopy (ssEM), light microscopy (LM) and synchrotron-based X-ray microscopy (XRM). Specially, XRM for three-dimensional (3D) imaging of large-scale brain tissue with high resolution and fast imaging speed is highlighted. Additionally, the development of elegant methods for acquisition of brain functions from electrical/chemical signals in the brain is outlined. In particular, the new electrophysiology technologies for neural recordings at the single-neuron level and in the brain are also summarized. We also focus on the construction of electrochemical probes based on dual-recognition strategy and surface/interface chemistry for determination of chemical species in the brain with high selectivity and long-term stability, as well as electrochemophysiological microarray for simultaneously recording of electrochemical and electrophysiological signals in the brain. Moreover, the recent development of brain MRI probes with high contrast-to-noise ratio (CNR) and sensitivity based on hyperpolarized techniques and multi-nuclear chemistry is introduced. Furthermore, multiple optical probes and instruments, especially the optophysiological Raman probes and fiber Raman photometry, for imaging and biosensing in live brain are emphasized. Finally, a brief perspective on existing challenges and further research development is provided.
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Affiliation(s)
- Zhichao Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
| | - Ying Zhu
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Liming Zhang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
| | - Weiping Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Yawei Liu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 China
| | - Qiaowei Tang
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Xiaoqing Cai
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Jiang Li
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Lihua Wang
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Changlu Tao
- Interdisciplinary Center for Brain Information, Brain Cognition and Brain Disease Institute, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 China
| | | | - Xiaowei Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Shangguo Hou
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, 518055 China
| | - Dawei Jiang
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022 China
| | - Kai Liu
- Department of Chemistry, Tsinghua University, Beijing, 100084 China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Hongjie Zhang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 China
- Department of Chemistry, Tsinghua University, Beijing, 100084 China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
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25
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [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: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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26
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Active forgetting requires Sickie function in a dedicated dopamine circuit in Drosophila. Proc Natl Acad Sci U S A 2022; 119:e2204229119. [PMID: 36095217 PMCID: PMC9499536 DOI: 10.1073/pnas.2204229119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Forgetting is an essential component of the brain's memory management system, providing a balance to memory formation processes by removing unused or unwanted memories, or by suppressing their expression. However, the molecular, cellular, and circuit mechanisms underlying forgetting are poorly understood. Here we show that the memory suppressor gene, sickie, functions in a single dopamine neuron (DAn) by supporting the process of active forgetting in Drosophila. RNAi knockdown (KD) of sickie impairs forgetting by reducing the Ca2+ influx and DA release from the DAn that promotes forgetting. Coimmunoprecipitation/mass spectrometry analyses identified cytoskeletal and presynaptic active zone (AZ) proteins as candidates that physically interact with Sickie, and a focused RNAi screen of the candidates showed that Bruchpilot (Brp)-a presynaptic AZ protein that regulates calcium channel clustering and neurotransmitter release-impairs active forgetting like sickie KD. In addition, overexpression of brp rescued the impaired forgetting of sickie KD, providing evidence that they function in the same process. Moreover, we show that sickie KD in the DAn reduces the abundance and size of AZ markers but increases their number, suggesting that Sickie controls DAn activity for forgetting by modulating the presynaptic AZ structure. Our results identify a molecular and circuit mechanism for normal levels of active forgetting and reveal a surprising role of Sickie in maintaining presynaptic AZ structure for neurotransmitter release.
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27
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Andreani T, Rosensweig C, Sisobhan S, Ogunlana E, Kath W, Allada R. Circadian programming of the ellipsoid body sleep homeostat in Drosophila. eLife 2022; 11:e74327. [PMID: 35735904 PMCID: PMC9270026 DOI: 10.7554/elife.74327] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 06/23/2022] [Indexed: 11/18/2022] Open
Abstract
Homeostatic and circadian processes collaborate to appropriately time and consolidate sleep and wake. To understand how these processes are integrated, we scheduled brief sleep deprivation at different times of day in Drosophila and find elevated morning rebound compared to evening. These effects depend on discrete morning and evening clock neurons, independent of their roles in circadian locomotor activity. In the R5 ellipsoid body sleep homeostat, we identified elevated morning expression of activity dependent and presynaptic gene expression as well as the presynaptic protein BRUCHPILOT consistent with regulation by clock circuits. These neurons also display elevated calcium levels in response to sleep loss in the morning, but not the evening consistent with the observed time-dependent sleep rebound. These studies reveal the circuit and molecular mechanisms by which discrete circadian clock neurons program a homeostatic sleep center.
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Affiliation(s)
- Tomas Andreani
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Clark Rosensweig
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Shiju Sisobhan
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - Emmanuel Ogunlana
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
| | - William Kath
- Department of Engineering Sciences and Applied Mathematics, Northwestern UniversityEvanstonUnited States
| | - Ravi Allada
- Department of Neurobiology, Northwestern UniversityChicagoUnited States
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28
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Duhart JC, Mosca TJ. Genetic regulation of central synapse formation and organization in Drosophila melanogaster. Genetics 2022; 221:6597078. [PMID: 35652253 DOI: 10.1093/genetics/iyac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 01/04/2023] Open
Abstract
A goal of modern neuroscience involves understanding how connections in the brain form and function. Such a knowledge is essential to inform how defects in the exquisite complexity of nervous system growth influence neurological disease. Studies of the nervous system in the fruit fly Drosophila melanogaster enabled the discovery of a wealth of molecular and genetic mechanisms underlying development of synapses-the specialized cell-to-cell connections that comprise the essential substrate for information flow and processing in the nervous system. For years, the major driver of knowledge was the neuromuscular junction due to its ease of examination. Analogous studies in the central nervous system lagged due to a lack of genetic accessibility of specific neuron classes, synaptic labels compatible with cell-type-specific access, and high resolution, quantitative imaging strategies. However, understanding how central synapses form remains a prerequisite to understanding brain development. In the last decade, a host of new tools and techniques extended genetic studies of synapse organization into central circuits to enhance our understanding of synapse formation, organization, and maturation. In this review, we consider the current state-of-the-field. We first discuss the tools, technologies, and strategies developed to visualize and quantify synapses in vivo in genetically identifiable neurons of the Drosophila central nervous system. Second, we explore how these tools enabled a clearer understanding of synaptic development and organization in the fly brain and the underlying molecular mechanisms of synapse formation. These studies establish the fly as a powerful in vivo genetic model that offers novel insights into neural development.
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Affiliation(s)
- Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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29
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Bai Y, Suzuki T. Activity-dependent circuitry plasticity via the regulation of the histamine receptor level in the Drosophila visual system. Mol Cell Neurosci 2022; 119:103703. [PMID: 35122941 DOI: 10.1016/j.mcn.2022.103703] [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: 10/04/2021] [Revised: 12/19/2021] [Accepted: 01/27/2022] [Indexed: 10/19/2022] Open
Abstract
Activity-dependent synaptic plasticity is crucial for responses to the environment. Although the plasticity mechanisms of presynaptic photoreceptor neurons in the Drosophila visual system have been well studied, postsynaptic modifications remain elusive. In addition, further studies on the adaption of the visual system to different light experiences at a circuitry scale are required. Using the modified transcriptional reporter of intracellular Ca2+ method, we describe a way to visualize circuitry changes according to different light experiences. We found enhanced postsynaptic neuronal activity responses in lamina monopolar neuron L2 after prolonged light treatment. Although L1 also has connections with photoreceptors, there were no enhanced activity responses in L1. We also report in this study that activity-dependent transcriptional downregulation of inhibitory histamine receptor (HR), Ort, occurs in postsynaptic neuron L2, but not in L1, during continuous light conditions. We produced exogenous Ort proteins in L2 neurons and found that it attenuated the enhanced activity response caused by constant light exposure. These findings, together with the fact that histamine is the main inhibitory neurotransmitter released by photoreceptors in the Drosophila visual system, confirmed our hypothesis that the activity-dependent transcriptional downregulation of HR is responsible for the constant light exposure-induced circuitry response changes in L2. The results successfully demonstrated the selective circuit change after synaptic remodeling evoked by long-term activation and provided in vivo evidence of circuitry plasticity upon long-term environmental stimulation.
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Affiliation(s)
- Yiming Bai
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-0026, Japan
| | - Takashi Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-0026, Japan.
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30
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The Role of Even-Skipped in Drosophila Larval Somatosensory Circuit Assembly. eNeuro 2022; 9:ENEURO.0403-21.2021. [PMID: 35031555 PMCID: PMC8856706 DOI: 10.1523/eneuro.0403-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/11/2021] [Accepted: 12/19/2021] [Indexed: 11/21/2022] Open
Abstract
Proper somatosensory circuit assembly is critical for processing somatosensory stimuli and for responding accordingly. In comparison to other sensory circuits (e.g., olfactory and visual), somatosensory circuits have unique anatomy and function. However, understanding of somatosensory circuit development lags far behind that of other sensory systems. For example, there are few identified transcription factors required for integration of interneurons into functional somatosensory circuits. Here, as a model, we examine one type of somatosensory interneuron, Even-skipped (Eve) expressing laterally placed interneurons (ELs) of the Drosophila larval nerve cord. Eve is a highly conserved, homeodomain transcription factor known to play a role in cell fate specification and neuronal axon guidance. Because marker genes are often functionally important in the cell types they define, we deleted eve expression specifically from EL interneurons. On the cell biological level, using single neuron labeling, we find eve plays several previously undescribed roles in refinement of neuron morphogenesis. Eve suppresses aberrant neurite branching, promotes axon elongation, and regulates dorsal-ventral dendrite position. On the circuit level, using optogenetics, calcium imaging, and behavioral analysis, we find eve expression is required in EL interneurons for the normal encoding of somatosensory stimuli and for normal mapping of outputs to behavior. We conclude that the eve gene product coordinately regulates multiple aspects of EL interneuron morphogenesis and is critically required to properly integrate EL interneurons into somatosensory circuits. Our data shed light on the genetic regulation of somatosensory circuit assembly.
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31
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Bajar BT, Phi NT, Isaacman-Beck J, Reichl J, Randhawa H, Akin O. A discrete neuronal population coordinates brain-wide developmental activity. Nature 2022; 602:639-646. [PMID: 35140397 DOI: 10.1038/s41586-022-04406-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 01/05/2022] [Indexed: 11/09/2022]
Abstract
In vertebrates, stimulus-independent activity accompanies neural circuit maturation throughout the developing brain1,2. The recent discovery of similar activity in the developing Drosophila central nervous system suggests that developmental activity is fundamental to the assembly of complex brains3. How such activity is coordinated across disparate brain regions to influence synaptic development at the level of defined cell types is not well understood. Here we show that neurons expressing the cation channel transient receptor potential gamma (Trpγ) relay and pattern developmental activity throughout the Drosophila brain. In trpγ mutants, activity is attenuated globally, and both patterns of activity and synapse structure are altered in a cell-type-specific manner. Less than 2% of the neurons in the brain express Trpγ. These neurons arborize throughout the brain, and silencing or activating them leads to loss or gain of brain-wide activity. Together, these results indicate that this small population of neurons coordinates brain-wide developmental activity. We propose that stereotyped patterns of developmental activity are driven by a discrete, genetically specified network to instruct neural circuit assembly at the level of individual cells and synapses. This work establishes the fly brain as an experimentally tractable system for studying how activity contributes to synapse and circuit formation.
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Affiliation(s)
- Bryce T Bajar
- Department of Biological Chemistry, Medical Scientist Training Program, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, USA
| | - Nguyen T Phi
- Molecular, Cellular, and Integrative Physiology Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jesse Isaacman-Beck
- Department of Neurobiology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA
| | - Jun Reichl
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, USA
| | - Harpreet Randhawa
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, USA
| | - Orkun Akin
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, CA, USA.
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32
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Sneve MA, Piatkevich KD. Towards a Comprehensive Optical Connectome at Single Synapse Resolution via Expansion Microscopy. Front Synaptic Neurosci 2022; 13:754814. [PMID: 35115916 PMCID: PMC8803729 DOI: 10.3389/fnsyn.2021.754814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 12/17/2021] [Indexed: 12/04/2022] Open
Abstract
Mapping and determining the molecular identity of individual synapses is a crucial step towards the comprehensive reconstruction of neuronal circuits. Throughout the history of neuroscience, microscopy has been a key technology for mapping brain circuits. However, subdiffraction size and high density of synapses in brain tissue make this process extremely challenging. Electron microscopy (EM), with its nanoscale resolution, offers one approach to this challenge yet comes with many practical limitations, and to date has only been used in very small samples such as C. elegans, tadpole larvae, fruit fly brain, or very small pieces of mammalian brain tissue. Moreover, EM datasets require tedious data tracing. Light microscopy in combination with tissue expansion via physical magnification-known as expansion microscopy (ExM)-offers an alternative approach to this problem. ExM enables nanoscale imaging of large biological samples, which in combination with multicolor neuronal and synaptic labeling offers the unprecedented capability to trace and map entire neuronal circuits in fully automated mode. Recent advances in new methods for synaptic staining as well as new types of optical molecular probes with superior stability, specificity, and brightness provide new modalities for studying brain circuits. Here we review advanced methods and molecular probes for fluorescence staining of the synapses in the brain that are compatible with currently available expansion microscopy techniques. In particular, we will describe genetically encoded probes for synaptic labeling in mice, zebrafish, Drosophila fruit flies, and C. elegans, which enable the visualization of post-synaptic scaffolds and receptors, presynaptic terminals and vesicles, and even a snapshot of the synaptic activity itself. We will address current methods for applying these probes in ExM experiments, as well as appropriate vectors for the delivery of these molecular constructs. In addition, we offer experimental considerations and limitations for using each of these tools as well as our perspective on emerging tools.
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Affiliation(s)
- Madison A Sneve
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, United States
| | - Kiryl D Piatkevich
- School of Life Sciences, Westlake University, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Westlake University, Hangzhou, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China
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Kuljis DA, Micheva KD, Ray A, Wegner W, Bowman R, Madison DV, Willig KI, Barth AL. Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons. Int J Mol Sci 2021; 22:ijms221810032. [PMID: 34576197 PMCID: PMC8467468 DOI: 10.3390/ijms221810032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 11/26/2022] Open
Abstract
Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABAARs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions.
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Affiliation(s)
- Dika A. Kuljis
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Kristina D. Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Ajit Ray
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Waja Wegner
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Ryan Bowman
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Daniel V. Madison
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Katrin I. Willig
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Alison L. Barth
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
- Correspondence: ; Tel.: +1-412-268-1198
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34
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Motahari Z, Maynard TM, Popratiloff A, Moody SA, LaMantia AS. Aberrant early growth of individual trigeminal sensory and motor axons in a series of mouse genetic models of 22q11.2 deletion syndrome. Hum Mol Genet 2021; 29:3081-3093. [PMID: 32901287 PMCID: PMC7645708 DOI: 10.1093/hmg/ddaa199] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/29/2020] [Accepted: 09/01/2020] [Indexed: 02/06/2023] Open
Abstract
We identified divergent modes of initial axon growth that prefigure disrupted differentiation of the trigeminal nerve (CN V), a cranial nerve essential for suckling, feeding and swallowing (S/F/S), a key innate behavior compromised in multiple genetic developmental disorders including DiGeorge/22q11.2 Deletion Syndrome (22q11.2 DS). We combined rapid in vivo labeling of single CN V axons in LgDel+/− mouse embryos, a genomically accurate 22q11.2DS model, and 3D imaging to identify and quantify phenotypes that could not be resolved using existing methods. We assessed these phenotypes in three 22q11.2-related genotypes to determine whether individual CN V motor and sensory axons wander, branch and sprout aberrantly in register with altered anterior–posterior hindbrain patterning and gross morphological disruption of CN V seen in LgDel+/−. In the additional 22q11.2-related genotypes: Tbx1+/−, Ranbp1−/−, Ranbp1+/− and LgDel+/−:Raldh2+/−; axon phenotypes are seen when hindbrain patterning and CN V gross morphology is altered, but not when it is normal or restored toward WT. This disordered growth of CN V sensory and motor axons, whose appropriate targeting is critical for optimal S/F/S, may be an early, critical determinant of imprecise innervation leading to inefficient oropharyngeal function associated with 22q11.2 deletion from birth onward.
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Affiliation(s)
- Zahra Motahari
- Institute for Neuroscience, Washington, DC 20037, USA.,Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Thomas M Maynard
- The Fralin Biomedical Research Institute at Virginia Tech-Carilion School of Medicine, Roanoke, VA 24016, USA
| | - Anastas Popratiloff
- Institute for Neuroscience, Washington, DC 20037, USA.,Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Sally A Moody
- Institute for Neuroscience, Washington, DC 20037, USA.,Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Anthony-S LaMantia
- The Fralin Biomedical Research Institute at Virginia Tech-Carilion School of Medicine, Roanoke, VA 24016, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
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35
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Weiss JT, Donlea JM. Sleep deprivation results in diverse patterns of synaptic scaling across the Drosophila mushroom bodies. Curr Biol 2021; 31:3248-3261.e3. [PMID: 34107302 PMCID: PMC8355077 DOI: 10.1016/j.cub.2021.05.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/22/2021] [Accepted: 05/11/2021] [Indexed: 11/19/2022]
Abstract
Sleep is essential for a variety of plastic processes, including learning and memory. However, the consequences of insufficient sleep on circuit connectivity remain poorly understood. To better appreciate the effects of sleep loss on synaptic connectivity across a memory-encoding circuit, we examined changes in the distribution of synaptic markers in the Drosophila mushroom body (MB). Protein-trap tags for active zone components indicate that recent sleep time is inversely correlated with Bruchpilot (BRP) abundance in the MB lobes; sleep loss elevates BRP while sleep induction reduces BRP across the MB. Overnight sleep deprivation also elevated levels of dSyd-1 and Cacophony, but not other pre-synaptic proteins. Cell-type-specific genetic reporters show that MB-intrinsic Kenyon cells (KCs) exhibit increased pre-synaptic BRP throughout the axonal lobes after sleep deprivation; similar increases were not detected in projections from large interneurons or dopaminergic neurons that innervate the MB. These results indicate that pre-synaptic plasticity in KCs is responsible for elevated levels of BRP in the MB lobes of sleep-deprived flies. Because KCs provide synaptic inputs to several classes of post-synaptic partners, we next used a fluorescent reporter for synaptic contacts to test whether each class of KC output connections is scaled uniformly by sleep loss. The KC output synapses that we observed here can be divided into three classes: KCs to MB interneurons; KCs to dopaminergic neurons; and KCs to MB output neurons. No single class showed uniform scaling across each constituent member, indicating that different rules may govern plasticity during sleep loss across cell types.
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Affiliation(s)
- Jacqueline T Weiss
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA; Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jeffrey M Donlea
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095, USA.
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36
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Cell-type-specific, multicolor labeling of endogenous proteins with split fluorescent protein tags in Drosophila. Proc Natl Acad Sci U S A 2021; 118:2024690118. [PMID: 34074768 DOI: 10.1073/pnas.2024690118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The impact of the Drosophila experimental system on studies of modern biology cannot be understated. The ability to tag endogenously expressed proteins is essential to maximize the use of this model organism. Here, we describe a method for labeling endogenous proteins with self-complementing split fluorescent proteins (split FPs) in a cell-type-specific manner in Drosophila A short fragment of an FP coding sequence is inserted into a specific genomic locus while the remainder of the FP is expressed using an available GAL4 driver line. In consequence, complementation fluorescence allows examination of protein localization in particular cells. Besides, when inserting tandem repeats of the short FP fragment at the same genomic locus, we can substantially enhance the fluorescence signal. The enhanced signal is of great value in live-cell imaging at the subcellular level. We can also accomplish a multicolor labeling system with orthogonal split FPs. However, other orthogonal split FPs do not function for in vivo imaging besides split GFP. Through protein engineering and in vivo functional studies, we report a red split FP that we can use for duplexed visualization of endogenous proteins in intricate Drosophila tissues. Using the two orthogonal split FP systems, we have simultaneously imaged proteins that reside in distinct subsynaptic compartments. Our approach allows us to study the proximity between and localization of multiple proteins endogenously expressed in essentially any cell type in Drosophila.
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37
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Oh Y, Lai JSY, Min S, Huang HW, Liberles SD, Ryoo HD, Suh GSB. Periphery signals generated by Piezo-mediated stomach stretch and Neuromedin-mediated glucose load regulate the Drosophila brain nutrient sensor. Neuron 2021; 109:1979-1995.e6. [PMID: 34015253 DOI: 10.1016/j.neuron.2021.04.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/25/2021] [Accepted: 04/28/2021] [Indexed: 12/24/2022]
Abstract
Nutrient sensors allow animals to identify foods rich in specific nutrients. The Drosophila nutrient sensor, diuretic hormone 44 (DH44) neurons, helps the fly to detect nutritive sugar. This sensor becomes operational during starvation; however, the mechanisms by which DH44 neurons or other nutrient sensors are regulated remain unclear. Here, we identified two satiety signals that inhibit DH44 neurons: (1) Piezo-mediated stomach/crop stretch after food ingestion and (2) Neuromedin/Hugin neurosecretory neurons in the ventral nerve cord (VNC) activated by an increase in the internal glucose level. A subset of Piezo+ neurons that express DH44 neuropeptide project to the crop. We found that DH44 neuronal activity and food intake were stimulated following a knockdown of piezo in DH44 neurons or silencing of Hugin neurons in the VNC, even in fed flies. Together, we propose that these two qualitatively distinct peripheral signals work in concert to regulate the DH44 nutrient sensor during the fed state.
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Affiliation(s)
- Yangkyun Oh
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York, NY 10016, USA; Neuroscience Institute, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Jason Sih-Yu Lai
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York, NY 10016, USA; Neuroscience Institute, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Soohong Min
- Harvard Medical School, Howard Hughes Medical Institute, Department of Cell Biology, Boston, MA 02115, USA
| | - Huai-Wei Huang
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Stephen D Liberles
- Harvard Medical School, Howard Hughes Medical Institute, Department of Cell Biology, Boston, MA 02115, USA
| | - Hyung Don Ryoo
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York, NY 10016, USA
| | - Greg S B Suh
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York, NY 10016, USA; Neuroscience Institute, NYU Grossman School of Medicine, New York, NY 10016, USA; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.
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38
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Choi BJ, Chen YCD, Desplan C. Building a circuit through correlated spontaneous neuronal activity in the developing vertebrate and invertebrate visual systems. Genes Dev 2021; 35:677-691. [PMID: 33888564 PMCID: PMC8091978 DOI: 10.1101/gad.348241.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
During the development of the vertebrate nervous systems, genetic programs assemble an immature circuit that is subsequently refined by neuronal activity evoked by external stimuli. However, prior to sensory experience, the intrinsic property of the developing nervous system also triggers correlated network-level neuronal activity, with retinal waves in the developing vertebrate retina being the best documented example. Spontaneous activity has also been found in the visual system of Drosophila Here, we compare the spontaneous activity of the developing visual system between mammalian and Drosophila and suggest that Drosophila is an emerging model for mechanistic and functional studies of correlated spontaneous activity.
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Affiliation(s)
- Ben Jiwon Choi
- Department of Biology, New York University, New York, New York 10003, USA
| | | | - Claude Desplan
- Department of Biology, New York University, New York, New York 10003, USA
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39
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Takechi H, Hakeda-Suzuki S, Nitta Y, Ishiwata Y, Iwanaga R, Sato M, Sugie A, Suzuki T. Glial insulin regulates cooperative or antagonistic Golden goal/Flamingo interactions during photoreceptor axon guidance. eLife 2021; 10:66718. [PMID: 33666170 PMCID: PMC7987344 DOI: 10.7554/elife.66718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/02/2021] [Indexed: 11/29/2022] Open
Abstract
Transmembrane protein Golden goal (Gogo) interacts with atypical cadherin Flamingo (Fmi) to direct R8 photoreceptor axons in the Drosophila visual system. However, the precise mechanisms underlying Gogo regulation during columnar- and layer-specific R8 axon targeting are unknown. Our studies demonstrated that the insulin secreted from surface and cortex glia switches the phosphorylation status of Gogo, thereby regulating its two distinct functions. Non-phosphorylated Gogo mediates the initial recognition of the glial protrusion in the center of the medulla column, whereas phosphorylated Gogo suppresses radial filopodia extension by counteracting Flamingo to maintain a one axon-to-one column ratio. Later, Gogo expression ceases during the midpupal stage, thus allowing R8 filopodia to extend vertically into the M3 layer. These results demonstrate that the long- and short-range signaling between the glia and R8 axon growth cones regulates growth cone dynamics in a stepwise manner, and thus shapes the entire organization of the visual system.
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Affiliation(s)
- Hiroki Takechi
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Satoko Hakeda-Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yohei Nitta
- Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,Brain Research Institute, Niigata University, Niigata, Japan
| | - Yuichi Ishiwata
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Riku Iwanaga
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Makoto Sato
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Japan.,Laboratory of Developmental Neurobiology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Atsushi Sugie
- Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,Brain Research Institute, Niigata University, Niigata, Japan
| | - Takashi Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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40
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Song BJ, Sharp SJ, Rogulja D. Daily rewiring of a neural circuit generates a predictive model of environmental light. SCIENCE ADVANCES 2021; 7:7/13/eabe4284. [PMID: 33762336 PMCID: PMC7990339 DOI: 10.1126/sciadv.abe4284] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/03/2021] [Indexed: 05/02/2023]
Abstract
Behavioral responsiveness to external stimulation is shaped by context. We studied how sensory information can be contextualized, by examining light-evoked locomotor responsiveness of Drosophila relative to time of day. We found that light elicits an acute increase in locomotion (startle) that is modulated in a time-of-day-dependent manner: Startle is potentiated during the nighttime, when light is unexpected, but is suppressed during the daytime. The internal daytime-nighttime context is generated by two interconnected and functionally opposing populations of circadian neurons-LNvs generating the daytime state and DN1as generating the nighttime state. Switching between the two states requires daily remodeling of LNv and DN1a axons such that the maximum presynaptic area in one population coincides with the minimum in the other. We propose that a dynamic model of environmental light resides in the shifting connectivities of the LNv-DN1a circuit, which helps animals evaluate ongoing conditions and choose a behavioral response.
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Affiliation(s)
- Bryan J Song
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Slater J Sharp
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Dragana Rogulja
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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41
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Puñal VM, Ahmed M, Thornton-Kolbe EM, Clowney EJ. Untangling the wires: development of sparse, distributed connectivity in the mushroom body calyx. Cell Tissue Res 2021; 383:91-112. [PMID: 33404837 PMCID: PMC9835099 DOI: 10.1007/s00441-020-03386-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/07/2020] [Indexed: 01/16/2023]
Abstract
Appropriate perception and representation of sensory stimuli pose an everyday challenge to the brain. In order to represent the wide and unpredictable array of environmental stimuli, principle neurons of associative learning regions receive sparse, combinatorial sensory inputs. Despite the broad role of such networks in sensory neural circuits, the developmental mechanisms underlying their emergence are not well understood. As mammalian sensory coding regions are numerically complex and lack the accessibility of simpler invertebrate systems, we chose to focus this review on the numerically simpler, yet functionally similar, Drosophila mushroom body calyx. We bring together current knowledge about the cellular and molecular mechanisms orchestrating calyx development, in addition to drawing insights from literature regarding construction of sparse wiring in the mammalian cerebellum. From this, we formulate hypotheses to guide our future understanding of the development of this critical perceptual center.
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Affiliation(s)
- Vanessa M. Puñal
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Department of Molecular & Integrative Physiology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Maria Ahmed
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Emma M. Thornton-Kolbe
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Neuroscience Graduate Program, The University of Michigan, Ann Arbor, MI 48109, USA
| | - E. Josephine Clowney
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
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42
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Akin O, Zipursky SL. Activity regulates brain development in the fly. Curr Opin Genet Dev 2020; 65:8-13. [DOI: 10.1016/j.gde.2020.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/14/2020] [Indexed: 12/31/2022]
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43
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Liu H, Pizzano S, Li R, Zhao W, Veling MW, Hu Y, Yang L, Ye B. isoTarget: A Genetic Method for Analyzing the Functional Diversity of Splicing Isoforms In Vivo. Cell Rep 2020; 33:108361. [PMID: 33176150 PMCID: PMC7685093 DOI: 10.1016/j.celrep.2020.108361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 08/31/2020] [Accepted: 10/16/2020] [Indexed: 12/11/2022] Open
Abstract
Protein isoforms generated by alternative splicing contribute to proteome diversity. Because of the lack of effective techniques, the isoform-specific function, expression, localization, and signaling of endogenous proteins are unknown for most genes. Here, we report a genetic method, isoTarget, for multi-purpose studies of targeted isoforms in select cells. Applying isoTarget to two isoforms of Drosophila Dscam, Dscam[TM1] and [TM2], we found that, in neurons, endogenous Dscam[TM1] is in dendrites, whereas Dscam[TM2] is in both dendrites and axons. We demonstrate that the difference in subcellular localization, rather than biochemical properties, leads to the two isoforms’ functional differences. Moreover, we show that the subcellular enrichment of functional partners results in a DLK/Wallenda-Dscam[TM2]-Dock signaling cascade in axons. We further apply isoTarget to study two isoforms of a GABA receptor to demonstrate its general applicability. isoTarget is an effective technique for studying how alternative splicing enhances proteome complexity. Liu et al. develop a genetic method that enables the investigation of isoform-specific function, expression, localization, and signaling of endogenous proteins in select cells. Using this method, they demonstrate that the difference in subcellular localization of two isoforms of Down syndrome cell adhesion molecule leads to functional differences between them.
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Affiliation(s)
- Hao Liu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sarah Pizzano
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ruonan Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wenquan Zhao
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Macy W Veling
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yujia Hu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Limin Yang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; School of Medicine, Dalian University, Dalian, Liaoning, 116622, China
| | - Bing Ye
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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44
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Fendl S, Vieira RM, Borst A. Conditional protein tagging methods reveal highly specific subcellular distribution of ion channels in motion-sensing neurons. eLife 2020; 9:62953. [PMID: 33079061 PMCID: PMC7655108 DOI: 10.7554/elife.62953] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/14/2020] [Indexed: 11/25/2022] Open
Abstract
Neurotransmitter receptors and ion channels shape the biophysical properties of neurons, from the sign of the response mediated by neurotransmitter receptors to the dynamics shaped by voltage-gated ion channels. Therefore, knowing the localizations and types of receptors and channels present in neurons is fundamental to our understanding of neural computation. Here, we developed two approaches to visualize the subcellular localization of specific proteins in Drosophila: The flippase-dependent expression of GFP-tagged receptor subunits in single neurons and ‘FlpTag’, a versatile new tool for the conditional labelling of endogenous proteins. Using these methods, we investigated the subcellular distribution of the receptors GluClα, Rdl, and Dα7 and the ion channels para and Ih in motion-sensing T4/T5 neurons of the Drosophila visual system. We discovered a strictly segregated subcellular distribution of these proteins and a sequential spatial arrangement of glutamate, acetylcholine, and GABA receptors along the dendrite that matched the previously reported EM-reconstructed synapse distributions.
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Affiliation(s)
- Sandra Fendl
- Max Planck Institute of Neurobiology, Martinsried, Germany.,Graduate School of Systemic Neurosciences, LMU Munich, Martinsried, Germany
| | | | - Alexander Borst
- Max Planck Institute of Neurobiology, Martinsried, Germany.,Graduate School of Systemic Neurosciences, LMU Munich, Martinsried, Germany
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45
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Han X, Wang M, Liu C, Trush O, Takayama R, Akiyama T, Naito T, Tomomizu T, Imamura K, Sato M. DWnt4 and DWnt10 Regulate Morphogenesis and Arrangement of Columnar Units via Fz2/PCP Signaling in the Drosophila Brain. Cell Rep 2020; 33:108305. [PMID: 33113378 DOI: 10.1016/j.celrep.2020.108305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 09/13/2020] [Accepted: 10/02/2020] [Indexed: 01/09/2023] Open
Abstract
Columns are structural and functional units of the brain. However, the mechanism of column formation remains unclear. The medulla of the fly visual center shares features with the mammalian cerebral cortex, such as columnar and layered structures, and provides a good opportunity to study the mechanisms of column formation. Column formation is initiated by three core neurons in the medulla, namely, Mi1, R8, and R7. The proper orientation of neurons is required for the orientation and arrangement of multiple columns. Their orientations may be under the control of planar cell polarity (PCP) signaling, because it is known to regulate the orientation of cells in two-dimensional tissue structures. In this study, we demonstrate that the ligands DWnt4 and DWnt10 expressed specifically in the ventral medulla and dorsal medulla, respectively, globally regulate the columnar arrangement and orientation of Mi1 and R8 terminals through Fz2/PCP signaling in a three-dimensional space.
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Affiliation(s)
- Xujun Han
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan; Nano Life Science Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Miaoxing Wang
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Chuyan Liu
- Laboratory of Developmental Neurobiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Olena Trush
- Laboratory of Developmental Neurobiology, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Rie Takayama
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Takaaki Akiyama
- Division of Electrical Engineering and Computer Science, Graduate School of Natural Science and Technology, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Toshiki Naito
- Graduate School of Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Takeshi Tomomizu
- Graduate School of Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Kousuke Imamura
- Faculty of Electrical, Information and Communication Engineering, Institute of Science and Engineering, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Makoto Sato
- Mathematical Neuroscience Unit, Institute for Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan; Graduate School of Frontier Science Initiative, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan.
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46
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Araki T, Osaka J, Kato Y, Shimozono M, Kawamura H, Iwanaga R, Hakeda-Suzuki S, Suzuki T. Systematic identification of genes regulating synaptic remodeling in the Drosophila visual system. Genes Genet Syst 2020; 95:101-110. [PMID: 32493879 DOI: 10.1266/ggs.19-00066] [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] [Indexed: 11/23/2022] Open
Abstract
In many animals, neural activity contributes to the adaptive refinement of synaptic properties, such as firing frequency and the number of synapses, for learning, memorizing and adapting for survival. However, the molecular mechanisms underlying such activity-dependent synaptic remodeling remain largely unknown. In the synapses of Drosophila melanogaster, the presynaptic active zone (AZ) forms a T-shaped presynaptic density comprising AZ proteins, including Bruchpilot (Brp). In a previous study, we found that the signal from a fusion protein molecular marker consisting of Brp and mCherry becomes diffuse under continuous light over three days (LL), reflecting disassembly of the AZ, while remaining punctate under continuous darkness. To identify the molecular players controlling this synaptic remodeling, we used the fusion protein molecular marker and performed RNAi screening against 208 neuron-related transmembrane genes that are highly expressed in the Drosophila visual system. Second analyses using the STaR (synaptic tagging with recombination) technique, which showed a decrease in synapse number under the LL condition, and subsequent mutant and overexpression analysis confirmed that five genes are involved in the activity-dependent AZ disassembly. This work demonstrates the feasibility of identifying genes involved in activity-dependent synaptic remodeling in Drosophila, and also provides unexpected insight into the molecular mechanisms involved in cholesterol metabolism and biosynthesis of the insect molting hormone ecdysone.
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Affiliation(s)
- Tomohiro Araki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | - Jiro Osaka
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | - Yuya Kato
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | - Mai Shimozono
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | - Hinata Kawamura
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | - Riku Iwanaga
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
| | | | - Takashi Suzuki
- Graduate School of Life Science and Technology, Tokyo Institute of Technology
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Baccino-Calace M, Prieto D, Cantera R, Egger B. Compartment and cell-type specific hypoxia responses in the developing Drosophila brain. Biol Open 2020; 9:9/8/bio053629. [PMID: 32816692 PMCID: PMC7449796 DOI: 10.1242/bio.053629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Environmental factors such as the availability of oxygen are instructive cues that regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell-type specific levels of hypoxia. The values correlate with differential tracheolation that is observed throughout development between the central brain and the optic lobe. Neural stem cells in both compartments show the strongest hypoxia response while intermediate progenitors, neurons and glial cells reveal weaker responses. We demonstrate that the distance between a cell and the next closest tracheole is a good predictor of the hypoxic state of that cell. Our study indicates that oxygen availability appears to be the major factor controlling the hypoxia response in the developing Drosophila brain and that cell intrinsic and cell-type specific factors contribute to modulate the response in an unexpected manner. This article has an associated First Person interview with the first author of the paper. Summary: A fluorescent biosensor reveals cell type specific hypoxia levels in the Drosophila brain in unprecedented detail. It paves the way for further functional studies addressing the role of oxygen in neural stem cell maintenance and differentiation.
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Affiliation(s)
- Martin Baccino-Calace
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Daniel Prieto
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Rafael Cantera
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay.,Zoology Department, Stockholm University, Stockholm 106 91, Sweden
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg CH-1700, Switzerland
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Kennedy T, Rinker D, Broadie K. Genetic background mutations drive neural circuit hyperconnectivity in a fragile X syndrome model. BMC Biol 2020; 18:94. [PMID: 32731855 PMCID: PMC7392683 DOI: 10.1186/s12915-020-00817-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 06/19/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Neural circuits are initially assembled during development when neurons synapse with potential partners and later refined as appropriate connections stabilize into mature synapses while inappropriate contacts are eliminated. Disruptions to this synaptogenic process impair connectivity optimization and can cause neurodevelopmental disorders. Intellectual disability (ID) and autism spectrum disorder (ASD) are often characterized by synaptic overgrowth, with the maintenance of immature or inappropriate synapses. Such synaptogenic defects can occur through mutation of a single gene, such as fragile X mental retardation protein (FMRP) loss causing the neurodevelopmental disorder fragile X syndrome (FXS). FXS represents the leading heritable cause of ID and ASD, but many other genes that play roles in ID and ASD have yet to be identified. RESULTS In a Drosophila FXS disease model, one dfmr150M null mutant stock exhibits previously unreported axonal overgrowths at developmental and mature stages in the giant fiber (GF) escape circuit. These excess axon projections contain both chemical and electrical synapse markers, indicating mixed synaptic connections. Extensive analyses show these supernumerary synapses connect known GF circuit neurons, rather than new, inappropriate partners, indicating hyperconnectivity within the circuit. Despite the striking similarities to well-characterized FXS synaptic defects, this new GF circuit hyperconnectivity phenotype is driven by genetic background mutations in this dfmr150M stock. Similar GF circuit synaptic overgrowth is not observed in independent dfmr1 null alleles. Bulked segregant analysis (BSA) was combined with whole genome sequencing (WGS) to identify the quantitative trait loci (QTL) linked to neural circuit hyperconnectivity. The results reveal 8 QTL associated with inappropriate synapse formation and maintenance in the dfmr150M mutant background. CONCLUSIONS Synaptogenesis is a complex, precisely orchestrated neurodevelopmental process with a large cohort of gene products coordinating the connectivity, synaptic strength, and excitatory/inhibitory balance between neuronal partners. This work identifies a number of genetic regions that contain mutations disrupting proper synaptogenesis within a particularly well-mapped neural circuit. These QTL regions contain potential new genes involved in synapse formation and refinement. Given the similarity of the synaptic overgrowth phenotype to known ID and ASD inherited conditions, identifying these genes should increase our understanding of these devastating neurodevelopmental disease states.
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Affiliation(s)
- Tyler Kennedy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - David Rinker
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Department of Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN, 37235, USA.
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49
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Bensussen S, Shankar S, Ching KH, Zemel D, Ta TL, Mount RA, Shroff SN, Gritton HJ, Fabris P, Vanbenschoten H, Beck C, Man HY, Han X. A Viral Toolbox of Genetically Encoded Fluorescent Synaptic Tags. iScience 2020; 23:101330. [PMID: 32674057 PMCID: PMC7363701 DOI: 10.1016/j.isci.2020.101330] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 04/18/2020] [Accepted: 06/26/2020] [Indexed: 01/16/2023] Open
Abstract
Fibronectin intrabodies generated with mRNA display (FingRs) are a recently developed tool for labeling excitatory or inhibitory synapses, with the benefit of not altering endogenous synaptic protein expression levels or synaptic transmission. Here, we generated a viral vector FingR toolbox that allows for multi-color, neuron-type-specific labeling of excitatory or inhibitory synapses in multiple brain regions. We screened various fluorophores, FingR fusion configurations, and transcriptional control regulations in adeno-associated virus (AAV) and retrovirus vector designs. We report the development of a red FingR variant and demonstrated dual labeling of excitatory and inhibitory synapses in the same cells. Furthermore, we developed cre-inducible FingR AAV variants and demonstrated their utility, finding that the density of inhibitory synapses in aspiny striatal cholinergic interneurons remained unchanged in response to dopamine depletion. Finally, we generated FingR retroviral vectors, which enabled us to track the development of excitatory and inhibitory synapses in hippocampal adult-born granule cells.
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Affiliation(s)
- Seth Bensussen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sneha Shankar
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kimberley H Ching
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Dana Zemel
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Tina L Ta
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Rebecca A Mount
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sanaya N Shroff
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Howard J Gritton
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Pierre Fabris
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | | | - Connor Beck
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Xue Han
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
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50
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Hörmann N, Schilling T, Ali AH, Serbe E, Mayer C, Borst A, Pujol-Martí J. A combinatorial code of transcription factors specifies subtypes of visual motion-sensing neurons in Drosophila. Development 2020; 147:223179. [PMID: 32238425 PMCID: PMC7240302 DOI: 10.1242/dev.186296] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/20/2020] [Indexed: 12/21/2022]
Abstract
Direction-selective T4/T5 neurons exist in four subtypes, each tuned to visual motion along one of the four cardinal directions. Along with their directional tuning, neurons of each T4/T5 subtype orient their dendrites and project their axons in a subtype-specific manner. Directional tuning, thus, appears strictly linked to morphology in T4/T5 neurons. How the four T4/T5 subtypes acquire their distinct morphologies during development remains largely unknown. Here, we investigated when and how the dendrites of the four T4/T5 subtypes acquire their specific orientations, and profiled the transcriptomes of all T4/T5 neurons during this process. This revealed a simple and stable combinatorial code of transcription factors defining the four T4/T5 subtypes during their development. Changing the combination of transcription factors of specific T4/T5 subtypes resulted in predictable and complete conversions of subtype-specific properties, i.e. dendrite orientation and matching axon projection pattern. Therefore, a combinatorial code of transcription factors coordinates the development of dendrite and axon morphologies to generate anatomical specializations that differentiate subtypes of T4/T5 motion-sensing neurons. Summary: Morphological and transcriptomic analyses allowed the identification of a combinatorial code of transcription factors that controls the development of subtype-specific morphologies in motion-detecting neurons of the Drosophila visual system.
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Affiliation(s)
- Nikolai Hörmann
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Tabea Schilling
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Aicha Haji Ali
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Etienne Serbe
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Christian Mayer
- Laboratory of Neurogenomics, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Alexander Borst
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Jesús Pujol-Martí
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
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