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Christenson MP, Sanz Diez A, Heath SL, Saavedra-Weisenhaus M, Adachi A, Nern A, Abbott LF, Behnia R. Hue selectivity from recurrent circuitry in Drosophila. Nat Neurosci 2024; 27:1137-1147. [PMID: 38755272 DOI: 10.1038/s41593-024-01640-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 04/04/2024] [Indexed: 05/18/2024]
Abstract
In the perception of color, wavelengths of light reflected off objects are transformed into the derived quantities of brightness, saturation and hue. Neurons responding selectively to hue have been reported in primate cortex, but it is unknown how their narrow tuning in color space is produced by upstream circuit mechanisms. We report the discovery of neurons in the Drosophila optic lobe with hue-selective properties, which enables circuit-level analysis of color processing. From our analysis of an electron microscopy volume of a whole Drosophila brain, we construct a connectomics-constrained circuit model that accounts for this hue selectivity. Our model predicts that recurrent connections in the circuit are critical for generating hue selectivity. Experiments using genetic manipulations to perturb recurrence in adult flies confirm this prediction. Our findings reveal a circuit basis for hue selectivity in color vision.
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Affiliation(s)
- Matthias P Christenson
- Zuckerman Institute, Columbia University, New York, NY, USA
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Alvaro Sanz Diez
- Zuckerman Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Sarah L Heath
- Zuckerman Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Maia Saavedra-Weisenhaus
- Zuckerman Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Atsuko Adachi
- Zuckerman Institute, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - L F Abbott
- Zuckerman Institute, Columbia University, New York, NY, USA
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA
- Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY, USA
| | - Rudy Behnia
- Zuckerman Institute, Columbia University, New York, NY, USA.
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA.
- Kavli Institute for Brain Science, Columbia University Medical Center, New York, NY, USA.
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2
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Bustillo ME, Douthit J, Astigarraga S, Treisman JE. Two distinct mechanisms of Plexin A function in Drosophila optic lobe lamination and morphogenesis. Development 2024; 151:dev202237. [PMID: 38738602 PMCID: PMC11190435 DOI: 10.1242/dev.202237] [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: 04/28/2024] [Indexed: 05/14/2024]
Abstract
Visual circuit development is characterized by subdivision of neuropils into layers that house distinct sets of synaptic connections. We find that, in the Drosophila medulla, this layered organization depends on the axon guidance regulator Plexin A. In Plexin A null mutants, synaptic layers of the medulla neuropil and arborizations of individual neurons are wider and less distinct than in controls. Analysis of semaphorin function indicates that Semaphorin 1a, acting in a subset of medulla neurons, is the primary partner for Plexin A in medulla lamination. Removal of the cytoplasmic domain of endogenous Plexin A has little effect on the formation of medulla layers; however, both null and cytoplasmic domain deletion mutations of Plexin A result in an altered overall shape of the medulla neuropil. These data suggest that Plexin A acts as a receptor to mediate morphogenesis of the medulla neuropil, and as a ligand for Semaphorin 1a to subdivide it into layers. Its two independent functions illustrate how a few guidance molecules can organize complex brain structures by each playing multiple roles.
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Affiliation(s)
- Maria E. Bustillo
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Jessica Douthit
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Sergio Astigarraga
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
| | - Jessica E. Treisman
- Department of Cell Biology, New York University Grossman School of Medicine, 435 E. 30th Street, New York, NY 10016, USA
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3
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Malin JA, Chen YC, Simon F, Keefer E, Desplan C. Spatial patterning controls neuron numbers in the Drosophila visual system. Dev Cell 2024; 59:1132-1145.e6. [PMID: 38531357 PMCID: PMC11078608 DOI: 10.1016/j.devcel.2024.03.004] [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: 08/10/2023] [Revised: 12/18/2023] [Accepted: 03/01/2024] [Indexed: 03/28/2024]
Abstract
Neurons must be made in the correct proportions to communicate with the appropriate synaptic partners and form functional circuits. In the Drosophila visual system, multiple subtypes of distal medulla (Dm) inhibitory interneurons are made in distinct, reproducible numbers-from 5 to 800 per optic lobe. These neurons are born from a crescent-shaped neuroepithelium called the outer proliferation center (OPC), which can be subdivided into specific domains based on transcription factor and growth factor expression. We fate mapped Dm neurons and found that more abundant neural types are born from larger neuroepithelial subdomains, while less abundant subtypes are born from smaller ones. Additionally, morphogenetic Dpp/BMP signaling provides a second layer of patterning that subdivides the neuroepithelium into smaller domains to provide more granular control of cell proportions. Apoptosis appears to play a minor role in regulating Dm neuron abundance. This work describes an underappreciated mechanism for the regulation of neuronal stoichiometry.
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Affiliation(s)
- Jennifer A Malin
- Department of Biology, New York University, New York, NY 10003, USA.
| | - Yen-Chung Chen
- Department of Biology, New York University, New York, NY 10003, USA
| | - Félix Simon
- Department of Biology, New York University, New York, NY 10003, USA
| | - Evelyn Keefer
- Department of Biology, New York University, New York, NY 10003, USA
| | - Claude Desplan
- Department of Biology, New York University, New York, NY 10003, USA.
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4
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Wang Y, Salazar RJ, Simonetta LT, Sorrentino V, Gatton TJ, Wu B, Vecsey CG, Carrillo RA. hkb is required for DIP-α expression and target recognition in the Drosophila neuromuscular circuit. Commun Biol 2024; 7:507. [PMID: 38678127 PMCID: PMC11055905 DOI: 10.1038/s42003-024-06184-8] [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: 07/19/2023] [Accepted: 04/11/2024] [Indexed: 04/29/2024] Open
Abstract
Our nervous system contains billions of neurons that form precise connections with each other through interactions between cell surface proteins. In Drosophila, the Dpr and DIP immunoglobulin protein subfamilies form homophilic or heterophilic interactions to instruct synaptic connectivity, synaptic growth, and cell survival. However, the upstream regulatory mechanisms of Dprs and DIPs are not clear. On the other hand, while transcription factors have been implicated in target recognition, their downstream cell surface proteins remain mostly unknown. We conduct an F1 dominant modifier genetic screen to identify regulators of Dprs and DIPs. We identify huckebein (hkb), a transcription factor previously implicated in target recognition of the dorsal Is motor neuron. We show that hkb genetically interacts with DIP-α and loss of hkb leads to complete removal of DIP-α expression specifically in dorsal Is motor neurons. We then confirm that this specificity is through the dorsal Is motor neuron specific transcription factor, even-skipped (eve), which acts downstream of hkb. Analysis of the genetic interaction between hkb and eve reveals that they act in the same pathway to regulate dorsal Is motor neuron connectivity. Our study provides insight into the transcriptional regulation of DIP-α and suggests that distinct regulatory mechanisms exist for the same CSP in different neurons.
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Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 20147, USA.
| | - Rio J Salazar
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Luciano T Simonetta
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
| | - Violet Sorrentino
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA
| | - Terrence J Gatton
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Bill Wu
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Christopher G Vecsey
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Robert A Carrillo
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL, 60637, USA.
- Neuroscience Institute, University of Chicago, Chicago, IL, 60637, USA.
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
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5
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Matsliah A, Yu SC, Kruk K, Bland D, Burke A, Gager J, Hebditch J, Silverman B, Willie K, Willie RW, Sorek M, Sterling AR, Kind E, Garner D, Sancer G, Wernet MF, Kim SS, Murthy M, Seung HS. Neuronal "parts list" and wiring diagram for a visual system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.12.562119. [PMID: 37873160 PMCID: PMC10592826 DOI: 10.1101/2023.10.12.562119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
A catalog of neuronal cell types has often been called a "parts list" of the brain, and regarded as a prerequisite for understanding brain function. In the optic lobe of Drosophila, rules of connectivity between cell types have already proven essential for understanding fly vision. Here we analyze the fly connectome to complete the list of cell types intrinsic to the optic lobe, as well as the rules governing their connectivity. We more than double the list of known types. Most new cell types contain between 10 and 100 cells, and integrate information over medium distances in the visual field. Some existing type families (Tm, Li, and LPi) at least double in number of types. We introduce a new Sm interneuron family, which contains more types than any other, and three new families of cross-neuropil types. Self-consistency of cell types is demonstrated through automatic assignment of cells to types by distance in high-dimensional feature space, and further validation is provided by algorithms that select small subsets of discriminative features. Cell types with similar connectivity patterns divide into clusters that are interpretable in terms of motion, object, and color vision. Our work showcases the advantages of connectomic cell typing: complete and unbiased sampling, a rich array of features based on connectivity, and reduction of the connectome to a drastically simpler wiring diagram of cell types, with immediate relevance for brain function and development.
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Affiliation(s)
| | - Szi-Chieh Yu
- Neuroscience Institute, Princeton University, USA
| | | | - Doug Bland
- Neuroscience Institute, Princeton University, USA
| | - Austin Burke
- Neuroscience Institute, Princeton University, USA
| | - Jay Gager
- Neuroscience Institute, Princeton University, USA
| | | | | | - Kyle Willie
- Neuroscience Institute, Princeton University, USA
| | | | | | | | - Emil Kind
- Institut für Biologie - Neurobiologie, Freie Universität B erlin, Germany
| | - Dustin Garner
- Molecular, Cellular, and Developmental Biology, Univ. C alifornia Santa Barbara, USA
| | - Gizem Sancer
- Institut für Biologie - Neurobiologie, Freie Universität B erlin, Germany
| | - Mathias F Wernet
- Institut für Biologie - Neurobiologie, Freie Universität B erlin, Germany
| | - Sung Soo Kim
- Molecular, Cellular, and Developmental Biology, Univ. C alifornia Santa Barbara, USA
| | - Mala Murthy
- Neuroscience Institute, Princeton University, USA
| | - H Sebastian Seung
- Neuroscience Institute, Princeton University, USA
- Computer Science Department, Princeton University, U SA
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6
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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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7
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Cornean J, Molina-Obando S, Gür B, Bast A, Ramos-Traslosheros G, Chojetzki J, Lörsch L, Ioannidou M, Taneja R, Schnaitmann C, Silies M. Heterogeneity of synaptic connectivity in the fly visual system. Nat Commun 2024; 15:1570. [PMID: 38383614 PMCID: PMC10882054 DOI: 10.1038/s41467-024-45971-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/08/2024] [Indexed: 02/23/2024] Open
Abstract
Visual systems are homogeneous structures, where repeating columnar units retinotopically cover the visual field. Each of these columns contain many of the same neuron types that are distinguished by anatomic, genetic and - generally - by functional properties. However, there are exceptions to this rule. In the 800 columns of the Drosophila eye, there is an anatomically and genetically identifiable cell type with variable functional properties, Tm9. Since anatomical connectivity shapes functional neuronal properties, we identified the presynaptic inputs of several hundred Tm9s across both optic lobes using the full adult female fly brain (FAFB) electron microscopic dataset and FlyWire connectome. Our work shows that Tm9 has three major and many sparsely distributed inputs. This differs from the presynaptic connectivity of other Tm neurons, which have only one major, and more stereotypic inputs than Tm9. Genetic synapse labeling showed that the heterogeneous wiring exists across individuals. Together, our data argue that the visual system uses heterogeneous, distributed circuit properties to achieve robust visual processing.
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Affiliation(s)
- Jacqueline Cornean
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Sebastian Molina-Obando
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Burak Gür
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Annika Bast
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Giordano Ramos-Traslosheros
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonas Chojetzki
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Lena Lörsch
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Maria Ioannidou
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Rachita Taneja
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Christopher Schnaitmann
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany
| | - Marion Silies
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University, 55128, Mainz, Germany.
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8
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Wolterhoff N, Hiesinger PR. Synaptic promiscuity in brain development. Curr Biol 2024; 34:R102-R116. [PMID: 38320473 PMCID: PMC10849093 DOI: 10.1016/j.cub.2023.12.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Precise synaptic connectivity is a prerequisite for the function of neural circuits, yet individual neurons, taken out of their developmental context, readily form unspecific synapses. How does the genome encode brain wiring in light of this apparent contradiction? Synaptic specificity is the outcome of a long series of developmental processes and mechanisms before, during and after synapse formation. How much promiscuity is permissible or necessary at the moment of synaptic partner choice depends on the extent to which prior development restricts available partners or subsequent development corrects initially made synapses. Synaptic promiscuity at the moment of choice can thereby play important roles in the development of precise connectivity, but also facilitate developmental flexibility and robustness. In this review, we assess the experimental evidence for the prevalence and roles of promiscuous synapse formation during brain development. Many well-established experimental approaches are based on developmental genetic perturbation and an assessment of synaptic connectivity only in the adult; this can make it difficult to pinpoint when a given defect or mechanism occurred. In many cases, such studies reveal mechanisms that restrict partner availability already prior to synapse formation. Subsequently, at the moment of choice, factors including synaptic competency, interaction dynamics and molecular recognition further restrict synaptic partners. The discussion of the development of synaptic specificity through the lens of synaptic promiscuity suggests an algorithmic process based on neurons capable of promiscuous synapse formation that are continuously prevented from making the wrong choices, with no single mechanism or developmental time point sufficient to explain the outcome.
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Affiliation(s)
- Neele Wolterhoff
- Division of Neurobiology, Free University Berlin, 14195 Berlin, Germany
| | - P Robin Hiesinger
- Division of Neurobiology, Free University Berlin, 14195 Berlin, Germany.
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9
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Lobb-Rabe M, Nawrocka WI, Zhang R, Ashley J, Carrillo RA, Özkan E. Neuronal Wiring Receptors Dprs and DIPs Are GPI Anchored and This Modification Contributes to Their Cell Surface Organization. eNeuro 2024; 11:ENEURO.0184-23.2023. [PMID: 38233143 PMCID: PMC10863630 DOI: 10.1523/eneuro.0184-23.2023] [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: 05/26/2023] [Revised: 11/20/2023] [Accepted: 12/15/2023] [Indexed: 01/19/2024] Open
Abstract
The Drosophila Dpr and DIP proteins belong to the immunoglobulin superfamily of cell surface proteins (CSPs). Their hetero- and homophilic interactions have been implicated in a variety of neuronal functions, including synaptic connectivity, cell survival, and axon fasciculation. However, the signaling pathways underlying these diverse functions are unknown. To gain insight into Dpr-DIP signaling, we sought to examine how these CSPs are associated with the membrane. Specifically, we asked whether Dprs and DIPs are integral membrane proteins or membrane anchored through the addition of glycosylphosphatidylinositol (GPI) linkage. We demonstrate that most Dprs and DIPs are GPI anchored to the membrane of insect cells and validate these findings for some family members in vivo using Drosophila larvae, where GPI anchor cleavage results in loss of surface labeling. Additionally, we show that GPI cleavage abrogates aggregation of insect cells expressing cognate Dpr-DIP partners. To test if the GPI anchor affects Dpr and DIP localization, we replaced it with a transmembrane domain and observed perturbation of subcellular localization on motor neurons and muscles. These data suggest that membrane anchoring of Dprs and DIPs through GPI linkage is required for localization and that Dpr-DIP intracellular signaling likely requires transmembrane coreceptors.
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Affiliation(s)
- Meike Lobb-Rabe
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
- Program in Cell and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
| | - Wioletta I Nawrocka
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637
| | - Ruiling Zhang
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
- Committee on Development, Regeneration, and Stem Cell Biology, The University of Chicago, Chicago, Illinois 60637
| | - James Ashley
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
| | - Robert A Carrillo
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
- Program in Cell and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
| | - Engin Özkan
- Neuroscience Institute, The University of Chicago, Chicago, Illinois 60637
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637
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10
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Ahmed OM, Crocker A, Murthy M. Transcriptional profiling of Drosophila male-specific P1 (pC1) neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566045. [PMID: 37986870 PMCID: PMC10659367 DOI: 10.1101/2023.11.07.566045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
In Drosophila melanogaster, the P1 (pC1) cluster of male-specific neurons both integrates sensory cues and drives or modulates behavioral programs such as courtship, in addition to contributing to a social arousal state. The behavioral function of these neurons is linked to the genes they express, which underpin their capacity for synaptic signaling, neuromodulation, and physiology. Yet, P1 (pC1) neurons have not been fully characterized at the transcriptome level. Moreover, it is unknown how the molecular landscape of P1 (pC1) neurons acutely changes after flies engage in social behaviors, where baseline P1 (pC1) neural activity is expected to increase. To address these two gaps, we use single cell-type RNA sequencing to profile and compare the transcriptomes of P1 (pC1) neurons harvested from socially paired versus solitary male flies. Compared to control transcriptome datasets, we find that P1 (pC1) neurons are enriched in 2,665 genes, including those encoding receptors, neuropeptides, and cell-adhesion molecules (dprs/DIPs). Furthermore, courtship is characterized by changes in ~300 genes, including those previously implicated in regulating behavior (e.g. DopEcR, Octβ3R, Fife, kairos, rad). Finally, we identify a suite of genes that link conspecific courtship with the innate immune system. Together, these data serve as a molecular map for future studies of an important set of higher-order and sexually-dimorphic neurons.
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Affiliation(s)
- Osama M Ahmed
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
- Department of Psychology, University of Washington, Seattle, WA 98105, USA
| | - Amanda Crocker
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
- Program in Neuroscience, Middlebury College, Middlebury, VT 05753, USA
| | - Mala Murthy
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08540, USA
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11
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Wang Y, Salazar R, Simonetta L, Sorrentino V, Gatton TJ, Wu B, Vecsey CG, Carrillo RA. hkb is required for DIP-α expression and target recognition in the Drosophila neuromuscular circuit. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.562341. [PMID: 37905128 PMCID: PMC10614772 DOI: 10.1101/2023.10.15.562341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Our nervous system contains billions of neurons that form precise connections with each other through interactions between cell surface proteins (CSPs). In Drosophila, the Dpr and DIP immunoglobulin protein subfamilies form homophilic or heterophilic interactions to instruct synaptic connectivity, synaptic growth and cell survival. However, the upstream regulation and downstream signaling mechanisms of Dprs and DIPs are not clear. In the Drosophila larval neuromuscular system, DIP-α is expressed in the dorsal and ventral type-Is motor neurons (MNs). We conducted an F1 dominant modifier genetic screen to identify regulators of Dprs and DIPs. We found that the transcription factor, huckebein (hkb), genetically interacts with DIP-α and is important for target recognition specifically in the dorsal Is MN, but not the ventral Is MN. Loss of hkb led to complete removal of DIP-α expression. We then confirmed that this specificity is through the dorsal Is MN specific transcription factor, even-skipped (eve), which acts downstream of hkb. Genetic interaction between hkb and eve revealed that they act in the same pathway to regulate dorsal Is MN connectivity. Our study provides insight into the transcriptional regulation of DIP-α and suggests that distinct regulatory mechanisms exist for the same CSP in different neurons.
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Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL 60637
- Neuroscience Institute, University of Chicago, Chicago, IL 60637
- Current address: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147
- Co-first author
| | - Rio Salazar
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL 60637
- Neuroscience Institute, University of Chicago, Chicago, IL 60637
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637
- Co-first author
| | - Luciano Simonetta
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL 60637
- Neuroscience Institute, University of Chicago, Chicago, IL 60637
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637
| | - Violet Sorrentino
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL 60637
- Neuroscience Institute, University of Chicago, Chicago, IL 60637
- Current address: Molecular and Cell Biology Graduate Program, University of Washington, Seattle, Washington 98195
| | - Terrence J. Gatton
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866
| | - Bill Wu
- Neuroscience Program, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866
| | | | - Robert A. Carrillo
- Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, IL 60637
- Neuroscience Institute, University of Chicago, Chicago, IL 60637
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637
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12
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Bustillo ME, Douthit J, Astigarraga S, Treisman JE. Two distinct mechanisms of Plexin A function in Drosophila optic lobe lamination and morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.07.552282. [PMID: 37609142 PMCID: PMC10441316 DOI: 10.1101/2023.08.07.552282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Visual circuit development is characterized by subdivision of neuropils into layers that house distinct sets of synaptic connections. We find that in the Drosophila medulla, this layered organization depends on the axon guidance regulator Plexin A. In plexin A null mutants, synaptic layers of the medulla neuropil and arborizations of individual neurons are wider and less distinct than in controls. Analysis of Semaphorin function indicates that Semaphorin 1a, provided by cells that include Tm5 neurons, is the primary partner for Plexin A in medulla lamination. Removal of the cytoplasmic domain of endogenous Plexin A does not disrupt the formation of medulla layers; however, both null and cytoplasmic domain deletion mutations of plexin A result in an altered overall shape of the medulla neuropil. These data suggest that Plexin A acts as a receptor to mediate morphogenesis of the medulla neuropil, and as a ligand for Semaphorin 1a to subdivide it into layers. Its two independent functions illustrate how a few guidance molecules can organize complex brain structures by each playing multiple roles. Summary statement The axon guidance molecule Plexin A has two functions in Drosophila medulla development; morphogenesis of the neuropil requires its cytoplasmic domain, but establishing synaptic layers through Semaphorin 1a does not.
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13
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Christenson MP, Díez ÁS, Heath SL, Saavedra-Weisenhaus M, Adachi A, Abbott LF, Behnia R. Hue selectivity from recurrent circuitry in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548573. [PMID: 37502934 PMCID: PMC10369983 DOI: 10.1101/2023.07.12.548573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
A universal principle of sensory perception is the progressive transformation of sensory information from broad non-specific signals to stimulus-selective signals that form the basis of perception. To perceive color, our brains must transform the wavelengths of light reflected off objects into the derived quantities of brightness, saturation and hue. Neurons responding selectively to hue have been reported in primate cortex, but it is unknown how their narrow tuning in color space is produced by upstream circuit mechanisms. To enable circuit level analysis of color perception, we here report the discovery of neurons in the Drosophila optic lobe with hue selective properties. Using the connectivity graph of the fly brain, we construct a connectomics-constrained circuit model that accounts for this hue selectivity. Unexpectedly, our model predicts that recurrent connections in the circuit are critical for hue selectivity. Experiments using genetic manipulations to perturb recurrence in adult flies confirms this prediction. Our findings reveal the circuit basis for hue selectivity in color vision.
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14
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Lobb-Rabe M, DeLong K, Salazar RJ, Zhang R, Wang Y, Carrillo RA. Dpr10 and Nocte are required for Drosophila motor axon pathfinding. Neural Dev 2022; 17:10. [PMID: 36271407 PMCID: PMC9585758 DOI: 10.1186/s13064-022-00165-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/19/2022] [Indexed: 11/18/2022] Open
Abstract
The paths axons travel to reach their targets and the subsequent synaptic connections they form are highly stereotyped. How cell surface proteins (CSPs) mediate these processes is not completely understood. The Drosophila neuromuscular junction (NMJ) is an ideal system to study how pathfinding and target specificity are accomplished, as the axon trajectories and innervation patterns are known and easily visualized. Dpr10 is a CSP required for synaptic partner choice in the neuromuscular and visual circuits and for axon pathfinding in olfactory neuron organization. In this study, we show that Dpr10 is also required for motor axon pathfinding. To uncover how Dpr10 mediates this process, we used immunoprecipitation followed by mass spectrometry to identify Dpr10 associated proteins. One of these, Nocte, is an unstructured, intracellular protein implicated in circadian rhythm entrainment. We mapped nocte expression in larvae and found it widely expressed in neurons, muscles, and glia. Cell-specific knockdown suggests nocte is required presynaptically to mediate motor axon pathfinding. Additionally, we found that nocte and dpr10 genetically interact to control NMJ assembly, suggesting that they function in the same molecular pathway. Overall, these data reveal novel roles for Dpr10 and its newly identified interactor, Nocte, in motor axon pathfinding and provide insight into how CSPs regulate circuit assembly.
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Affiliation(s)
- Meike Lobb-Rabe
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637 USA
| | - Katherine DeLong
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA
| | - Rio J. Salazar
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637 USA
| | - Ruiling Zhang
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637 USA
| | - Yupu Wang
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637 USA
| | - Robert A. Carrillo
- grid.170205.10000 0004 1936 7822Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Neuroscience Institute, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637 USA ,grid.170205.10000 0004 1936 7822Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637 USA
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15
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Chen PJ, Li Y, Lee CH. Calcium Imaging of Neural Activity in Fly Photoreceptors. Cold Spring Harb Protoc 2022; 2022:Pdb.top107800. [PMID: 35641092 DOI: 10.1101/pdb.top107800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Functional imaging methodologies allow researchers to simultaneously monitor the neural activities of all single neurons in a population, and this ability has led to great advances in neuroscience research. Taking advantage of a genetically tractable model organism, functional imaging in Drosophila provides opportunities to probe scientific questions that were previously unanswerable by electrophysiological recordings. Here, we introduce comprehensive protocols for two-photon calcium imaging in fly visual neurons. We also discuss some challenges in applying optical imaging techniques to study visual systems and consider the best practices for making comparisons between different neuron groups.
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Affiliation(s)
- Pei-Ju Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
| | - Yan Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
| | - Chi-Hon Lee
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
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16
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Wang Y, Lobb-Rabe M, Ashley J, Chatterjee P, Anand V, Bellen HJ, Kanca O, Carrillo RA. Systematic expression profiling of Dpr and DIP genes reveals cell surface codes in Drosophila larval motor and sensory neurons. Development 2022; 149:dev200355. [PMID: 35502740 PMCID: PMC9188756 DOI: 10.1242/dev.200355] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/20/2022] [Indexed: 07/26/2023]
Abstract
In complex nervous systems, neurons must identify their correct partners to form synaptic connections. The prevailing model to ensure correct recognition posits that cell-surface proteins (CSPs) in individual neurons act as identification tags. Thus, knowing what cells express which CSPs would provide insights into neural development, synaptic connectivity, and nervous system evolution. Here, we investigated expression of Dpr and DIP genes, two CSP subfamilies belonging to the immunoglobulin superfamily, in Drosophila larval motor neurons (MNs), muscles, glia and sensory neurons (SNs) using a collection of GAL4 driver lines. We found that Dpr genes are more broadly expressed than DIP genes in MNs and SNs, and each examined neuron expresses a unique combination of Dpr and DIP genes. Interestingly, many Dpr and DIP genes are not robustly expressed, but are found instead in gradient and temporal expression patterns. In addition, the unique expression patterns of Dpr and DIP genes revealed three uncharacterized MNs. This study sets the stage for exploring the functions of Dpr and DIP genes in Drosophila MNs and SNs and provides genetic access to subsets of neurons.
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Affiliation(s)
- Yupu Wang
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Meike Lobb-Rabe
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - James Ashley
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Purujit Chatterjee
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Veera Anand
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
| | - Hugo J. Bellen
- Department of Molecular and Human Genetics and Jan and Dan Duncan Neurobiological Research Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
- Department of Neuroscience and Howard Hughes Medical Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics and Jan and Dan Duncan Neurobiological Research Institute, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Robert A. Carrillo
- Department of Molecular Genetics & Cellular Biology, University of Chicago, Chicago, IL 60637, USA
- Neuroscience Institute, University of Chicago, Chicago, IL 60637, USA
- Committee on Development, Regeneration, and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
- Program in Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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17
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Meltzer H, Schuldiner O. Spatiotemporal Control of Neuronal Remodeling by Cell Adhesion Molecules: Insights From Drosophila. Front Neurosci 2022; 16:897706. [PMID: 35645712 PMCID: PMC9135462 DOI: 10.3389/fnins.2022.897706] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/22/2022] [Indexed: 01/26/2023] Open
Abstract
Developmental neuronal remodeling is required for shaping the precise connectivity of the mature nervous system. Remodeling involves pruning of exuberant neural connections, often followed by regrowth of adult-specific ones, as a strategy to refine neural circuits. Errors in remodeling are associated with neurodevelopmental disorders such as schizophrenia and autism. Despite its fundamental nature, our understanding of the mechanisms governing neuronal remodeling is far from complete. Specifically, how precise spatiotemporal control of remodeling and rewiring is achieved is largely unknown. In recent years, cell adhesion molecules (CAMs), and other cell surface and secreted proteins of various families, have been implicated in processes of neurite pruning and wiring specificity during circuit reassembly. Here, we review some of the known as well as speculated roles of CAMs in these processes, highlighting recent advances in uncovering spatiotemporal aspects of regulation. Our focus is on the fruit fly Drosophila, which is emerging as a powerful model in the field, due to the extensive, well-characterized and stereotypic remodeling events occurring throughout its nervous system during metamorphosis, combined with the wide and constantly growing toolkit to identify CAM binding and resulting cellular interactions in vivo. We believe that its many advantages pose Drosophila as a leading candidate for future breakthroughs in the field of neuronal remodeling in general, and spatiotemporal control by CAMs specifically.
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Affiliation(s)
- Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
- *Correspondence: Hagar Meltzer,
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
- Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
- Oren Schuldiner,
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18
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Xu S, Sergeeva AP, Katsamba PS, Mannepalli S, Bahna F, Bimela J, Zipursky SL, Shapiro L, Honig B, Zinn K. Affinity requirements for control of synaptic targeting and neuronal cell survival by heterophilic IgSF cell adhesion molecules. Cell Rep 2022; 39:110618. [PMID: 35385751 PMCID: PMC9078203 DOI: 10.1016/j.celrep.2022.110618] [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: 04/30/2021] [Revised: 02/01/2022] [Accepted: 03/14/2022] [Indexed: 11/24/2022] Open
Abstract
Neurons in the developing brain express many different cell adhesion molecules (CAMs) on their surfaces. CAM-binding affinities can vary by more than 200-fold, but the significance of these variations is unknown. Interactions between the immunoglobulin superfamily CAM DIP-α and its binding partners, Dpr10 and Dpr6, control synaptic targeting and survival of Drosophila optic lobe neurons. We design mutations that systematically change interaction affinity and analyze function in vivo. Reducing affinity causes loss-of-function phenotypes whose severity scales with the magnitude of the change. Synaptic targeting is more sensitive to affinity reduction than is cell survival. Increasing affinity rescues neurons that would normally be culled by apoptosis. By manipulating CAM expression together with affinity, we show that the key parameter controlling circuit assembly is surface avidity, which is the strength of adherence between cell surfaces. We conclude that CAM binding affinities and expression levels are finely tuned for function during development.
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Affiliation(s)
- Shuwa Xu
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
| | - Alina P Sergeeva
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - Phinikoula S Katsamba
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Seetha Mannepalli
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Fabiana Bahna
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Jude Bimela
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Lawrence Shapiro
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Barry Honig
- Department of Systems Biology, Columbia University Medical Center, New York, NY 10032, USA; Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Kai Zinn
- California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA.
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19
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Bali N, Lee HK(P, Zinn K. Sticks and Stones, a conserved cell surface ligand for the Type IIa RPTP Lar, regulates neural circuit wiring in Drosophila. eLife 2022; 11:e71469. [PMID: 35356892 PMCID: PMC9000958 DOI: 10.7554/elife.71469] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Type IIa receptor-like protein tyrosine phosphatases (RPTPs) are essential for neural development. They have cell adhesion molecule (CAM)-like extracellular domains that interact with cell-surface ligands and coreceptors. We identified the immunoglobulin superfamily CAM Sticks and Stones (Sns) as a new partner for the Drosophila Type IIa RPTP Lar. Lar and Sns bind to each other in embryos and in vitro, and the human Sns ortholog, Nephrin, binds to human Type IIa RPTPs. Genetic analysis shows that Lar and Sns function together to regulate larval neuromuscular junction development, axon guidance in the mushroom body (MB), and innervation of the optic lobe (OL) medulla by R7 photoreceptors. In the neuromuscular system, Lar and Sns are both required in motor neurons, and may function as coreceptors. In the MB and OL, however, the relevant Lar-Sns interactions are in trans (between neurons), so Sns functions as a Lar ligand in these systems.
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Affiliation(s)
- Namrata Bali
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Hyung-Kook (Peter) Lee
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
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20
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Kiral FR, Dutta SB, Linneweber GA, Hilgert S, Poppa C, Duch C, von Kleist M, Hassan BA, Hiesinger PR. Brain connectivity inversely scales with developmental temperature in Drosophila. Cell Rep 2021; 37:110145. [PMID: 34936868 DOI: 10.1016/j.celrep.2021.110145] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 10/04/2021] [Accepted: 11/29/2021] [Indexed: 11/17/2022] Open
Abstract
Variability of synapse numbers and partners despite identical genes reveals the limits of genetic determinism. Here, we use developmental temperature as a non-genetic perturbation to study variability of brain wiring and behavior in Drosophila. Unexpectedly, slower development at lower temperatures increases axo-dendritic branching, synapse numbers, and non-canonical synaptic partnerships of various neurons, while maintaining robust ratios of canonical synapses. Using R7 photoreceptors as a model, we show that changing the relative availability of synaptic partners using a DIPγ mutant that ablates R7's preferred partner leads to temperature-dependent recruitment of non-canonical partners to reach normal synapse numbers. Hence, R7 synaptic specificity is not absolute but based on the relative availability of postsynaptic partners and presynaptic control of synapse numbers. Behaviorally, movement precision is temperature robust, while movement activity is optimized for the developmentally encountered temperature. These findings suggest genetically encoded relative and scalable synapse formation to develop functional, but not identical, brains and behaviors.
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Affiliation(s)
- Ferdi Ridvan Kiral
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Suchetana B Dutta
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Gerit Arne Linneweber
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Selina Hilgert
- Institute of Developmental Biology and Neurobiology (iDN), Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Caroline Poppa
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Carsten Duch
- Institute of Developmental Biology and Neurobiology (iDN), Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Max von Kleist
- MF1 Bioinformatics, Robert Koch-Institute, 13353 Berlin, Germany
| | - Bassem A Hassan
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany; Institut du Cerveau - Paris Brain Institute - ICM, Sorbonne Université, Inserm, CNRS, Hôpital Pitié-Salpêtrière, Paris, France
| | - P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, 14195 Berlin, Germany.
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21
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Kind E, Longden KD, Nern A, Zhao A, Sancer G, Flynn MA, Laughland CW, Gezahegn B, Ludwig HDF, Thomson AG, Obrusnik T, Alarcón PG, Dionne H, Bock DD, Rubin GM, Reiser MB, Wernet MF. Synaptic targets of photoreceptors specialized to detect color and skylight polarization in Drosophila. eLife 2021; 10:e71858. [PMID: 34913436 PMCID: PMC8789284 DOI: 10.7554/elife.71858] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/15/2021] [Indexed: 11/18/2022] Open
Abstract
Color and polarization provide complementary information about the world and are detected by specialized photoreceptors. However, the downstream neural circuits that process these distinct modalities are incompletely understood in any animal. Using electron microscopy, we have systematically reconstructed the synaptic targets of the photoreceptors specialized to detect color and skylight polarization in Drosophila, and we have used light microscopy to confirm many of our findings. We identified known and novel downstream targets that are selective for different wavelengths or polarized light, and followed their projections to other areas in the optic lobes and the central brain. Our results revealed many synapses along the photoreceptor axons between brain regions, new pathways in the optic lobes, and spatially segregated projections to central brain regions. Strikingly, photoreceptors in the polarization-sensitive dorsal rim area target fewer cell types, and lack strong connections to the lobula, a neuropil involved in color processing. Our reconstruction identifies shared wiring and modality-specific specializations for color and polarization vision, and provides a comprehensive view of the first steps of the pathways processing color and polarized light inputs.
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Affiliation(s)
- Emil Kind
- Instititut für Biologie – Abteilung Neurobiologie, Fachbereich Biologie, Chemie & Pharmazie, Freie Universität BerlinBerlinGermany
| | - Kit D Longden
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Arthur Zhao
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gizem Sancer
- Instititut für Biologie – Abteilung Neurobiologie, Fachbereich Biologie, Chemie & Pharmazie, Freie Universität BerlinBerlinGermany
| | - Miriam A Flynn
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Connor W Laughland
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Bruck Gezahegn
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Henrique DF Ludwig
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Alex G Thomson
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Tessa Obrusnik
- Instititut für Biologie – Abteilung Neurobiologie, Fachbereich Biologie, Chemie & Pharmazie, Freie Universität BerlinBerlinGermany
| | - Paula G Alarcón
- Instititut für Biologie – Abteilung Neurobiologie, Fachbereich Biologie, Chemie & Pharmazie, Freie Universität BerlinBerlinGermany
| | - Heather Dionne
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Mathias F Wernet
- Instititut für Biologie – Abteilung Neurobiologie, Fachbereich Biologie, Chemie & Pharmazie, Freie Universität BerlinBerlinGermany
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22
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Li Y, Chen PJ, Lin TY, Ting CY, Muthuirulan P, Pursley R, Ilić M, Pirih P, Drews MS, Menon KP, Zinn KG, Pohida T, Borst A, Lee CH. Neural mechanism of spatio-chromatic opponency in the Drosophila amacrine neurons. Curr Biol 2021; 31:3040-3052.e9. [PMID: 34033749 DOI: 10.1016/j.cub.2021.04.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/18/2022]
Abstract
Visual animals detect spatial variations of light intensity and wavelength composition. Opponent coding is a common strategy for reducing information redundancy. Neurons equipped with both spatial and spectral opponency have been identified in vertebrates but not yet in insects. The Drosophila amacrine neuron Dm8 was recently reported to show color opponency. Here, we demonstrate Dm8 exhibits spatio-chromatic opponency. Antagonistic convergence of the direct input from the UV-sensing R7s and indirect input from the broadband receptors R1-R6 through Tm3 and Mi1 is sufficient to confer Dm8's UV/Vis (ultraviolet/visible light) opponency. Using high resolution monochromatic stimuli, we show the pale and yellow subtypes of Dm8s, inheriting retinal mosaic characteristics, have distinct spectral tuning properties. Using 2D white-noise stimulus and reverse correlation analysis, we found that the UV receptive field (RF) of Dm8 has a center-inhibition/surround-excitation structure. In the absence of UV-sensing R7 inputs, the polarity of the RF is inverted owing to the excitatory input from the broadband photoreceptors R1-R6. Using a new synGRASP method based on endogenous neurotransmitter receptors, we show that neighboring Dm8s form mutual inhibitory connections mediated by the glutamate-gated chloride channel GluClα, which is essential for both Dm8's spatial opponency and animals' phototactic behavior. Our study shows spatio-chromatic opponency could arise in the early visual stage, suggesting a common information processing strategy in both invertebrates and vertebrates.
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Affiliation(s)
- Yan Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Pei-Ju Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Tzu-Yang Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Chun-Yuan Ting
- Section on Neuronal Connectivity, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pushpanathan Muthuirulan
- Section on Neuronal Connectivity, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Randall Pursley
- Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Marko Ilić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Primož Pirih
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Michael S Drews
- Department Circuits-Computation-Models, Max-Planck-Institute of Neurobiology, 82152 Martinsried, Germany
| | - Kaushiki P Menon
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kai G Zinn
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Thomas Pohida
- Signal Processing and Instrumentation Section, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alexander Borst
- Department Circuits-Computation-Models, Max-Planck-Institute of Neurobiology, 82152 Martinsried, Germany
| | - Chi-Hon Lee
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
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Vision: Space and colour meet in the fly optic lobes. Curr Biol 2021; 31:R909-R912. [PMID: 34314720 DOI: 10.1016/j.cub.2021.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Colour vision involves colour-opponent cells, which are excited and inhibited by different wavelengths. Synaptic interconnections between Drosophila Dm8 cells are required for forming spatio-chromatic receptive fields with a center and surround of opposing polarity which can invert, depending on the stimulus.
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24
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Neural specification, targeting, and circuit formation during visual system assembly. Proc Natl Acad Sci U S A 2021; 118:2101823118. [PMID: 34183440 DOI: 10.1073/pnas.2101823118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Like other sensory systems, the visual system is topographically organized: Its sensory neurons, the photoreceptors, and their targets maintain point-to-point correspondence in physical space, forming a retinotopic map. The iterative wiring of circuits in the visual system conveniently facilitates the study of its development. Over the past few decades, experiments in Drosophila have shed light on the principles that guide the specification and connectivity of visual system neurons. In this review, we describe the main findings unearthed by the study of the Drosophila visual system and compare them with similar events in mammals. We focus on how temporal and spatial patterning generates diverse cell types, how guidance molecules distribute the axons and dendrites of neurons within the correct target regions, how vertebrates and invertebrates generate their retinotopic map, and the molecules and mechanisms required for neuronal migration. We suggest that basic principles used to wire the fly visual system are broadly applicable to other systems and highlight its importance as a model to study nervous system development.
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25
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Douthit J, Hairston A, Lee G, Morrison CA, Holguera I, Treisman JE. R7 photoreceptor axon targeting depends on the relative levels of lost and found expression in R7 and its synaptic partners. eLife 2021; 10:65895. [PMID: 34003117 PMCID: PMC8205486 DOI: 10.7554/elife.65895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/17/2021] [Indexed: 01/17/2023] Open
Abstract
As neural circuits form, growing processes select the correct synaptic partners through interactions between cell surface proteins. The presence of such proteins on two neuronal processes may lead to either adhesion or repulsion; however, the consequences of mismatched expression have rarely been explored. Here, we show that the Drosophila CUB-LDL protein Lost and found (Loaf) is required in the UV-sensitive R7 photoreceptor for normal axon targeting only when Loaf is also present in its synaptic partners. Although targeting occurs normally in loaf mutant animals, removing loaf from photoreceptors or expressing it in their postsynaptic neurons Tm5a/b or Dm9 in a loaf mutant causes mistargeting of R7 axons. Loaf localizes primarily to intracellular vesicles including endosomes. We propose that Loaf regulates the trafficking or function of one or more cell surface proteins, and an excess of these proteins on the synaptic partners of R7 prevents the formation of stable connections.
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Affiliation(s)
- Jessica Douthit
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, United States
| | - Ariel Hairston
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, United States
| | - Gina Lee
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, United States
| | - Carolyn A Morrison
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, United States
| | - Isabel Holguera
- Department of Biology, New York University, New York, United States
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, New York, United States
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26
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Pagni M, Haikala V, Oberhauser V, Meyer PB, Reiff DF, Schnaitmann C. Interaction of “chromatic” and “achromatic” circuits in Drosophila color opponent processing. Curr Biol 2021; 31:1687-1698.e4. [DOI: 10.1016/j.cub.2021.01.105] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023]
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27
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Roth H, Wernet MF. Colour opponency: Chromatic and achromatic circuits in the mix. Curr Biol 2021; 31:R378-R381. [PMID: 33905693 DOI: 10.1016/j.cub.2021.02.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The molecular genetic dissection of Drosophila colour vision circuitry reveals converging pathways previously categorized as being chromatic versus achromatic. Amacrine-like Dm8 cells receive direct and indirect inputs with different spectral sensitivity tuning, thereby forming the second stage of colour-opponent processing.
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Affiliation(s)
- Heidi Roth
- Freie Universität Berlin, Fachbereich Biologie, Chemie and Pharmazie, Institut für Biologie, Division of Neurobiology, Königin-Luise Strasse 1-3, 14195 Berlin, Germany
| | - Mathias F Wernet
- Freie Universität Berlin, Fachbereich Biologie, Chemie and Pharmazie, Institut für Biologie, Division of Neurobiology, Königin-Luise Strasse 1-3, 14195 Berlin, Germany.
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28
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Sancer G, Wernet MF. The development and function of neuronal subtypes processing color and skylight polarization in the optic lobes of Drosophila melanogaster. ARTHROPOD STRUCTURE & DEVELOPMENT 2021; 61:101012. [PMID: 33618155 DOI: 10.1016/j.asd.2020.101012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 11/01/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
The retinal mosaics of many insects contain different ommatidial subtypes harboring photoreceptors that are both molecularly and morphologically specialized for comparing between different wavelengths versus detecting the orientation of skylight polarization. The neural circuits underlying these different inputs and the characterization of their specific cellular elements are the subject of intense research. Here we review recent progress on the description of both assembly and function of color and skylight polarization circuitry, by focusing on two cell types located in the distal portion of the medulla neuropil of the fruit fly Drosophila melanogaster's optic lobes, called Dm8 and Dm9. In the main part of the retina, Dm8 cells fall into two molecularly distinct subtypes whose center becomes specifically connected to either one of randomly distributed 'pale' or 'yellow' R7 photoreceptor fates during development. Only in the 'dorsal rim area' (DRA), both polarization-sensitive R7 and R8 photoreceptors are connected to different Dm8-like cell types, called Dm-DRA1 and Dm-DRA2, respectively. An additional layer of interommatidial integration is introduced by Dm9 cells, which receive input from multiple neighboring R7 and R8 cells, as well as providing feedback synapses back into these photoreceptors. As a result, the response properties of color-sensitive photoreceptor terminals are sculpted towards being both maximally decorrelated, as well as harboring several levels of opponency (both columnar as well as intercolumnar). In the DRA, individual Dm9 cells appear to mix both polarization and color signals, thereby potentially serving as the first level of integration of different celestial stimuli. The molecular mechanisms underlying the establishment of these synaptic connections are beginning to be revealed, by using a combination of live imaging, developmental genetic studies, and cell type-specific transcriptomics.
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Affiliation(s)
- Gizem Sancer
- Freie Universität Berlin, Fachbereich Biologie, Chemie und Pharmazie, Institut für Biologie - Neurobiologie, Königin-Luise Strasse 1-3, 14195 Berlin, Germany
| | - Mathias F Wernet
- Freie Universität Berlin, Fachbereich Biologie, Chemie und Pharmazie, Institut für Biologie - Neurobiologie, Königin-Luise Strasse 1-3, 14195 Berlin, Germany.
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29
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Brovero SG, Fortier JC, Hu H, Lovejoy PC, Newell NR, Palmateer CM, Tzeng RY, Lee PT, Zinn K, Arbeitman MN. Investigation of Drosophila fruitless neurons that express Dpr/DIP cell adhesion molecules. eLife 2021; 10:e63101. [PMID: 33616528 PMCID: PMC7972454 DOI: 10.7554/elife.63101] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/22/2021] [Indexed: 12/16/2022] Open
Abstract
Drosophila reproductive behaviors are directed by fruitless neurons. A reanalysis of genomic studies shows that genes encoding dpr and DIP immunoglobulin superfamily (IgSF) members are expressed in fru P1 neurons. We find that each fru P1 and dpr/DIP (fru P1 ∩ dpr/DIP) overlapping expression pattern is similar in both sexes, but there are dimorphisms in neuronal morphology and cell number. Behavioral studies of fru P1 ∩ dpr/DIP perturbation genotypes indicate that the mushroom body functions together with the lateral protocerebral complex to direct courtship behavior. A single-cell RNA-seq analysis of fru P1 neurons shows that many DIPs have high expression in a small set of neurons, whereas the dprs are often expressed in a larger set of neurons at intermediate levels, with a myriad of dpr/DIP expression combinations. Functionally, we find that perturbations of sex hierarchy genes and of DIP-ε change the sex-specific morphologies of fru P1 ∩ DIP-α neurons.
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Affiliation(s)
- Savannah G Brovero
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Julia C Fortier
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Hongru Hu
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Pamela C Lovejoy
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Nicole R Newell
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Colleen M Palmateer
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Ruei-Ying Tzeng
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
| | - Kai Zinn
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Michelle N Arbeitman
- Department of Biomedical Sciences and Program of Neuroscience, Florida State University, College of MedicineTallahasseeUnited States
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30
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Heckman EL, Doe CQ. Establishment and Maintenance of Neural Circuit Architecture. J Neurosci 2021; 41:1119-1129. [PMID: 33568445 PMCID: PMC7888231 DOI: 10.1523/jneurosci.1143-20.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/29/2020] [Accepted: 12/09/2020] [Indexed: 02/03/2023] Open
Abstract
The ability to sense the world, process information, and navigate the environment depends on the assembly and continuous function of neural circuits in the brain. Within the past two decades, new technologies have rapidly advanced our understanding of how neural circuits are wired during development and how they are stably maintained, often for years. Electron microscopy reconstructions of model organism connectomes have provided a map of the stereotyped (and variable) connections in the brain; advanced light microscopy techniques have enabled direct observation of the cellular dynamics that underlie circuit construction and maintenance; transcriptomic and proteomic surveys of both developing and mature neurons have provided insights into the molecular and genetic programs governing circuit establishment and maintenance; and advanced genetic techniques have allowed for high-throughput discovery of wiring regulators. These tools have empowered scientists to rapidly generate and test hypotheses about how circuits establish and maintain connectivity. Thus, the set of principles governing circuit formation and maintenance have been expanded. These principles are discussed in this review.
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Affiliation(s)
- Emily L Heckman
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
| | - Chris Q Doe
- Institute of Neuroscience, Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403
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31
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Dorskind JM, Kolodkin AL. Revisiting and refining roles of neural guidance cues in circuit assembly. Curr Opin Neurobiol 2021; 66:10-21. [PMID: 32823181 PMCID: PMC10725571 DOI: 10.1016/j.conb.2020.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/16/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022]
Abstract
Neural guidance mechanisms ensure the precise targeting and synaptogenesis events essential for normal circuit function. Neuronal growth cones encounter numerous attractive and repulsive cues as they navigate toward their intermediate and final targets; temporal and spatial regulation of these responses are critical for circuit assembly. Recent work highlights the complexity of these events throughout neural development and the multifaceted functions of a wide range of guidance cues. Here, we discuss recent studies that leverage advances in genetics, single cell tracing, transcriptomics and proteomics to further our understanding of the molecular mechanisms underlying neural guidance and overall circuit organization.
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Affiliation(s)
- Joelle M Dorskind
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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32
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Minehart JA, Speer CM. A Picture Worth a Thousand Molecules-Integrative Technologies for Mapping Subcellular Molecular Organization and Plasticity in Developing Circuits. Front Synaptic Neurosci 2021; 12:615059. [PMID: 33469427 PMCID: PMC7813761 DOI: 10.3389/fnsyn.2020.615059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
A key challenge in developmental neuroscience is identifying the local regulatory mechanisms that control neurite and synaptic refinement over large brain volumes. Innovative molecular techniques and high-resolution imaging tools are beginning to reshape our view of how local protein translation in subcellular compartments drives axonal, dendritic, and synaptic development and plasticity. Here we review recent progress in three areas of neurite and synaptic study in situ-compartment-specific transcriptomics/translatomics, targeted proteomics, and super-resolution imaging analysis of synaptic organization and development. We discuss synergies between sequencing and imaging techniques for the discovery and validation of local molecular signaling mechanisms regulating synaptic development, plasticity, and maintenance in circuits.
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Affiliation(s)
| | - Colenso M. Speer
- Department of Biology, University of Maryland, College Park, MD, United States
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33
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Honig B, Shapiro L. Adhesion Protein Structure, Molecular Affinities, and Principles of Cell-Cell Recognition. Cell 2021; 181:520-535. [PMID: 32359436 DOI: 10.1016/j.cell.2020.04.010] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/25/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022]
Abstract
The ability of cells to organize into multicellular structures in precise patterns requires that they "recognize" one another with high specificity. We discuss recent progress in understanding the molecular basis of cell-cell recognition, including unique phenomena associated with neuronal interactions. We describe structures of select adhesion receptor complexes and their assembly into larger intercellular junction structures and discuss emerging principles that relate cell-cell organization to the binding specificities and energetics of adhesion receptors. Armed with these insights, advances in protein design and gene editing should pave the way for breakthroughs toward understanding the molecular basis of cell patterning in vivo.
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Affiliation(s)
- Barry Honig
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Lawrence Shapiro
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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34
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Luan H, Diao F, Scott RL, White BH. The Drosophila Split Gal4 System for Neural Circuit Mapping. Front Neural Circuits 2020; 14:603397. [PMID: 33240047 PMCID: PMC7680822 DOI: 10.3389/fncir.2020.603397] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 10/06/2020] [Indexed: 12/22/2022] Open
Abstract
The diversity and dense interconnectivity of cells in the nervous system present a huge challenge to understanding how brains work. Recent progress toward such understanding, however, has been fuelled by the development of techniques for selectively monitoring and manipulating the function of distinct cell types-and even individual neurons-in the brains of living animals. These sophisticated techniques are fundamentally genetic and have found their greatest application in genetic model organisms, such as the fruit fly Drosophila melanogaster. Drosophila combines genetic tractability with a compact, but cell-type rich, nervous system and has been the incubator for a variety of methods of neuronal targeting. One such method, called Split Gal4, is playing an increasingly important role in mapping neural circuits in the fly. In conjunction with functional perturbations and behavioral screens, Split Gal4 has been used to characterize circuits governing such activities as grooming, aggression, and mating. It has also been leveraged to comprehensively map and functionally characterize cells composing important brain regions, such as the central complex, lateral horn, and the mushroom body-the latter being the insect seat of learning and memory. With connectomics data emerging for both the larval and adult brains of Drosophila, Split Gal4 is also poised to play an important role in characterizing neurons of interest based on their connectivity. We summarize the history and current state of the Split Gal4 method and indicate promising areas for further development or future application.
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Affiliation(s)
| | | | | | - Benjamin H. White
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD, United States
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35
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Hiesinger PR. Brain wiring with composite instructions. Bioessays 2020; 43:e2000166. [PMID: 33145823 DOI: 10.1002/bies.202000166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 11/12/2022]
Abstract
The quest for molecular mechanisms that guide axons or specify synaptic contacts has largely focused on molecules that intuitively relate to the idea of an "instruction." By contrast, "permissive" factors are traditionally considered background machinery without contribution to the information content of a molecularly executed instruction. In this essay, I recast this dichotomy as a continuum from permissive to instructive actions of single factors that provide relative contributions to a necessarily collaborative effort. Individual molecules or other factors do not constitute absolute instructions by themselves; they provide necessary context for each other, thereby creating a composite that defines the overall instruction. The idea of composite instructions leads to two main conclusions: first, a composite of many seemingly permissive factors can define a specific instruction even in the absence of a single dominant contributor; second, individual factors are not necessarily related intuitively to the overall instruction or phenotypic outcome.
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Affiliation(s)
- P Robin Hiesinger
- Division of Neurobiology, Institute for Biology, Freie Universität Berlin, Berlin, Germany
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36
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Kurmangaliyev YZ, Yoo J, Valdes-Aleman J, Sanfilippo P, Zipursky SL. Transcriptional Programs of Circuit Assembly in the Drosophila Visual System. Neuron 2020; 108:1045-1057.e6. [PMID: 33125872 DOI: 10.1016/j.neuron.2020.10.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/31/2020] [Accepted: 10/03/2020] [Indexed: 12/19/2022]
Abstract
Precise patterns of synaptic connections between neurons are encoded in their genetic programs. Here, we use single-cell RNA sequencing to profile neuronal transcriptomes at multiple stages in the developing Drosophila visual system. We devise an efficient strategy for profiling neurons at multiple time points in a single pool, thereby minimizing batch effects and maximizing the reliability of time-course data. A transcriptional atlas spanning multiple stages is generated, including more than 150 distinct neuronal populations; of these, 88 are followed through synaptogenesis. This analysis reveals a common (pan-neuronal) program unfolding in highly coordinated fashion in all neurons, including genes encoding proteins comprising the core synaptic machinery and membrane excitability. This program is overlaid by cell-type-specific programs with diverse cell recognition molecules expressed in different combinations and at different times. We propose that a pan-neuronal program endows neurons with the competence to form synapses and that cell-type-specific programs control synaptic specificity.
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Affiliation(s)
- 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
| | - 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
| | - Javier Valdes-Aleman
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Piero Sanfilippo
- 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.
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37
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Rangel Olguin AG, Rochon PL, Krishnaswamy A. New Optical Tools to Study Neural Circuit Assembly in the Retina. Front Neural Circuits 2020; 14:44. [PMID: 32848633 PMCID: PMC7424070 DOI: 10.3389/fncir.2020.00044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/23/2020] [Indexed: 12/17/2022] Open
Abstract
During development, neurons navigate a tangled thicket of thousands of axons and dendrites to synapse with just a few specific targets. This phenomenon termed wiring specificity, is critical to the assembly of neural circuits and the way neurons manage this feat is only now becoming clear. Recent studies in the mouse retina are shedding new insight into this process. They show that specific wiring arises through a series of stages that include: directed axonal and dendritic growth, the formation of neuropil layers, positioning of such layers, and matching of co-laminar synaptic partners. Each stage appears to be directed by a distinct family of recognition molecules, suggesting that the combinatorial expression of such family members might act as a blueprint for retinal connectivity. By reviewing the evidence in support of each stage, and by considering their underlying molecular mechanisms, we attempt to synthesize these results into a wiring model which generates testable predictions for future studies. Finally, we conclude by highlighting new optical methods that could be used to address such predictions and gain further insight into this fundamental process.
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38
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Klimas A, Zhao Y. Expansion Microscopy: Toward Nanoscale Imaging of a Diverse Range of Biomolecules. ACS NANO 2020; 14:7689-7695. [PMID: 32628828 PMCID: PMC7456618 DOI: 10.1021/acsnano.0c04374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Expansion microscopy (ExM) has become a powerful imaging tool for visualizing the nanoscale organization of protein and nucleic acid targets in cells and tissues using only a conventional microscope. Until recently, current ExM approaches have had limited applicability to imaging other biomolecules, such as lipids and small molecules. With the new TRITON probes reported by Wen et al. in this issue of ACS Nano, ExM can now be used to perform nanoscale imaging of the cytoskeleton and lipid membranes. In this Perspective, we offer a brief overview of recent developments in ExM, with a focus on biomolecule anchoring and labeling strategies that target a wide range of biomolecules to the water-swellable polymer formed in situ, a key step that ensures biomolecules or labels of interest are separated in space and can be resolved on a conventional microscope. In addition to these new advancements, we discuss challenges and future directions in this exciting field.
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Affiliation(s)
- Aleksandra Klimas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Yongxin Zhao
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
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39
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Sanes JR, Zipursky SL. Synaptic Specificity, Recognition Molecules, and Assembly of Neural Circuits. Cell 2020; 181:536-556. [DOI: 10.1016/j.cell.2020.04.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/23/2020] [Accepted: 04/06/2020] [Indexed: 01/02/2023]
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40
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Schnaitmann C, Pagni M, Reiff DF. Color vision in insects: insights from Drosophila. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:183-198. [PMID: 32020291 PMCID: PMC7069916 DOI: 10.1007/s00359-019-01397-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/12/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Color vision is an important sensory capability that enhances the detection of contrast in retinal images. Monochromatic animals exclusively detect temporal and spatial changes in luminance, whereas two or more types of photoreceptors and neuronal circuitries for the comparison of their responses enable animals to differentiate spectral information independent of intensity. Much of what we know about the cellular and physiological mechanisms underlying color vision comes from research on vertebrates including primates. In insects, many important discoveries have been made, but direct insights into the physiology and circuit implementation of color vision are still limited. Recent advances in Drosophila systems neuroscience suggest that a complete insect color vision circuitry, from photoreceptors to behavior, including all elements and computations, can be revealed in future. Here, we review fundamental concepts in color vision alongside our current understanding of the neuronal basis of color vision in Drosophila, including side views to selected other insects.
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Affiliation(s)
- Christopher Schnaitmann
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Manuel Pagni
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany
| | - Dierk F Reiff
- Department for Animal Physiology and Neurobiology, Institute of Biology I, Albert-Ludwigs-University Freiburg, Freiburg, 79104, Germany.
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