1
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Erginkaya M, Cruz T, Brotas M, Marques A, Steck K, Nern A, Torrão F, Varela N, Bock DD, Reiser M, Chiappe ME. A competitive disinhibitory network for robust optic flow processing in Drosophila. Nat Neurosci 2025:10.1038/s41593-025-01948-9. [PMID: 40312577 DOI: 10.1038/s41593-025-01948-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 03/14/2025] [Indexed: 05/03/2025]
Abstract
Many animals navigate using optic flow, detecting rotational image velocity differences between their eyes to adjust direction. Forward locomotion produces strong symmetric translational optic flow that can mask these differences, yet the brain efficiently extracts these binocular asymmetries for course control. In Drosophila melanogaster, monocular horizontal system neurons facilitate detection of binocular asymmetries and contribute to steering. To understand these functions, we reconstructed horizontal system cells' central network using electron microscopy datasets, revealing convergent visual inputs, a recurrent inhibitory middle layer and a divergent output layer projecting to the ventral nerve cord and deeper brain regions. Two-photon imaging, GABA receptor manipulations and modeling, showed that lateral disinhibition reduces the output's translational sensitivity while enhancing its rotational selectivity. Unilateral manipulations confirmed the role of interneurons and descending outputs in steering. These findings establish competitive disinhibition as a key circuit mechanism for detecting rotational motion during translation, supporting navigation in dynamic environments.
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Affiliation(s)
- Mert Erginkaya
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
- Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Tomás Cruz
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
- Friedrich Miescher Institute for Biomedical Research, and Biozentrum, Department of Cell Biology, University of Basel, Basel, Switzerland
| | - Margarida Brotas
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
- CEDOC, iNOVA4Health, NOVA Medical School, Universidade Nova de Lisboa, Lisbon, Portugal
| | - André Marques
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Kathrin Steck
- Faculty of Science and Medicine, Department of Neuro and Movement Sciences, Université de Fribourg, Fribourg, Switzerland
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Filipa Torrão
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Nélia Varela
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Davi D Bock
- University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Michael Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - M Eugenia Chiappe
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.
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2
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Ogienko AA, Andreyeva EN, Yarinich LA, Pindyurin AV, Battulina NV, Omelina ES. Expression Pattern of the AB1-Gal4 Driver in Drosophila Third-Instar Larvae. Int J Mol Sci 2025; 26:3923. [PMID: 40362166 PMCID: PMC12071433 DOI: 10.3390/ijms26093923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2025] [Revised: 04/18/2025] [Accepted: 04/19/2025] [Indexed: 05/15/2025] Open
Abstract
Drosophila has provided a highly attractive model system for studying various tissue- and stage-specific processes as well as their pathologies, including a range of human diseases. The existence of a large number of diverse Gal4 drivers to precisely control the expression patterns of UAS transgenes simplifies such studies. However, the choice of driver is always critical, as its possible ectopic expression in non-target cells and tissues can directly impact the results. Therefore, it is very important to thoroughly characterize both the molecular nature and expression pattern of each Gal4 driver line. Here, we aim to fill such gaps regarding the AB1-Gal4 driver, which is typically used to express UAS transgenes in larval salivary glands. In this fly line, the P{GawB} enhancer trap construct encoding the Gal4 protein resides within overlapping evolutionary conserved spastin (spas) and Mitochondrial Rho (Miro) genes. Both these genes are expressed in a number of tissues, including the central nervous system (CNS), and their human orthologs are associated with neurodegenerative diseases. Consistently, we demonstrate that, in third-instar larvae, the expression pattern of AB1-Gal4 is also not restricted to salivary glands. We detect its activity in a subset of Elav-positive neurons in the CNS, including motor neurons, as well as in specific photoreceptor cells in eye discs.
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Affiliation(s)
| | | | | | | | | | - Evgeniya S. Omelina
- Institute of Molecular and Cellular Biology of the Siberian Branch of the Russian Academy of Sciences (IMCB SB RAS), 630090 Novosibirsk, Russia
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3
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Bell C, Kilo L, Gottschalk D, Arian J, Deneke L, Kern H, Rickert C, Kobler O, Strauß J, Heine M, Duch C, Ryglewski S. Specific presynaptic functions require distinct Drosophila Ca v2 splice isoforms. eLife 2025; 13:RP100394. [PMID: 39951027 PMCID: PMC11828482 DOI: 10.7554/elife.100394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2025] Open
Abstract
At many vertebrate synapses, presynaptic functions are tuned by expression of different Cav2 channels. Most invertebrate genomes contain only one Cav2 gene. The Drosophila Cav2 homolog, cacophony (cac), induces synaptic vesicle release at presynaptic active zones (AZs). We hypothesize that Drosophila cac functional diversity is enhanced by two mutually exclusive exon pairs that are not conserved in vertebrates, one in the voltage sensor and one in the loop binding Caβ and Gβγ subunits. We find that alternative splicing in the voltage sensor affects channel activation voltage. Only the isoform with the higher activation voltage localizes to AZs at the glutamatergic Drosophila larval neuromuscular junction and is imperative for normal synapse function. By contrast, alternative splicing at the other alternative exon pair tunes multiple aspects of presynaptic function. While expression of one exon yields normal transmission, expression of the other reduces channel number in the AZ and thus release probability. This also abolishes presynaptic homeostatic plasticity. Moreover, reduced channel number affects short-term plasticity, which is rescued by increasing the external calcium concentration to match release probability to control. In sum, in Drosophila alternative splicing provides a mechanism to regulate different aspects of presynaptic functions with only one Cav2 gene.
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Affiliation(s)
- Christopher Bell
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Lukas Kilo
- RWTH Aachen University, Lehrstuhl für EntwicklungsbiologieAachenGermany
| | - Daniel Gottschalk
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Jashar Arian
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Lea Deneke
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Hanna Kern
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Christof Rickert
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Oliver Kobler
- Leibniz Institute for Neurobiology Magdeburg, Combinatorial NeuroImaging Core FacilityMagdeburgGermany
| | - Julia Strauß
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Martin Heine
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Carsten Duch
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
| | - Stefanie Ryglewski
- Johannes Gutenberg University Mainz, Institute of Developmental Biology and Neurobiology, Biocenter 1MainzGermany
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4
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Bakshinska D, Liu WY, Schultz R, Stowers RS, Hoagland A, Cypranowska C, Stanley C, Younger SH, Newman ZL, Isacoff EY. Synapse-specific catecholaminergic modulation of neuronal glutamate release. Proc Natl Acad Sci U S A 2025; 122:e2420496121. [PMID: 39793084 PMCID: PMC11725921 DOI: 10.1073/pnas.2420496121] [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: 10/05/2024] [Accepted: 11/15/2024] [Indexed: 01/12/2025] Open
Abstract
Norepinephrine in vertebrates and its invertebrate analog, octopamine, regulate the activity of neural circuits. We find that, when hungry, Drosophila larvae switch activity in type II octopaminergic motor neurons (MNs) to high-frequency bursts, which coincide with locomotion-driving bursts in type I glutamatergic MNs that converge on the same muscles. Optical quantal analysis across hundreds of synapses simultaneously reveals that octopamine potentiates glutamate release by tonic type Ib MNs, but not phasic type Is MNs, and occurs via the Gq-coupled octopamine receptor (OAMB). OAMB is more abundant in type Ib terminals and acts through diacylglycerol and its target Unc13A, a key component of the glutamate release machinery. Potentiation varies significantly-by up to 1,000%-across synapses of a single Ib axon, with synaptic Unc13A levels determining both release probability and potentiation. We propose that a dual molecular mechanism-an upstream neuromodulator receptor and a downstream transmitter release controller-fine-tunes catecholaminergic modulation so that strong tonic synapses exhibit large potentiation, while weaker tonic and all phasic synapses maintain consistency, yielding a sophisticated regulation of locomotor behavior.
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Affiliation(s)
- Dariya Bakshinska
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA94720
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - William YuChen Liu
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Ryan Schultz
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA94720
| | - R. Steven Stowers
- Department of Microbiology & Cell Biology, Montana State University, Bozeman, MT59717
| | - Adam Hoagland
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Caroline Cypranowska
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Cherise Stanley
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Susan H. Younger
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Zachary L. Newman
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
| | - Ehud Y. Isacoff
- Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA94720
- Department of Neuroscience and Molecular & Cell Biology, University of California, Berkeley, CA94720
- Weill Neurohub, University of California Berkeley,Berkeley, CA94720
- Molecular Biophysics and Integrated BioImaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
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5
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Wani AR, Chowdhury B, Luong J, Chaya GM, Patel K, Isaacman-Beck J, Kayser MS, Syed MH. Stem cell-specific ecdysone signaling regulates the development of dorsal fan-shaped body neurons and sleep homeostasis. Curr Biol 2024; 34:4951-4967.e5. [PMID: 39383867 PMCID: PMC11537841 DOI: 10.1016/j.cub.2024.09.020] [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: 09/21/2023] [Revised: 08/09/2024] [Accepted: 09/11/2024] [Indexed: 10/11/2024]
Abstract
Complex behaviors arise from neural circuits that assemble from diverse cell types. Sleep is a conserved behavior essential for survival, yet little is known about how the nervous system generates neuron types of a sleep-wake circuit. Here, we focus on the specification of Drosophila 23E10-labeled dorsal fan-shaped body (dFB) long-field tangential input neurons that project to the dorsal layers of the fan-shaped body neuropil in the central complex. We use lineage analysis and genetic birth dating to identify two bilateral type II neural stem cells (NSCs) that generate 23E10 dFB neurons. We show that adult 23E10 dFB neurons express ecdysone-induced protein 93 (E93) and that loss of ecdysone signaling or E93 in type II NSCs results in their misspecification. Finally, we show that E93 knockdown in type II NSCs impairs adult sleep behavior. Our results provide insight into how extrinsic hormonal signaling acts on NSCs to generate the neuronal diversity required for adult sleep behavior. These findings suggest that some adult sleep disorders might derive from defects in stem cell-specific temporal neurodevelopmental programs.
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Affiliation(s)
- Adil R Wani
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, Albuquerque, NM 87131, USA
| | - Budhaditya Chowdhury
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA
| | - Jenny Luong
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gonzalo Morales Chaya
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, Albuquerque, NM 87131, USA
| | - Krishna Patel
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, Albuquerque, NM 87131, USA
| | | | - Matthew S Kayser
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Chronobiology Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Mubarak Hussain Syed
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, Albuquerque, NM 87131, USA.
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6
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Pokusaeva VO, Satapathy R, Symonova O, Joesch M. Bilateral interactions of optic-flow sensitive neurons coordinate course control in flies. Nat Commun 2024; 15:8830. [PMID: 39396050 PMCID: PMC11470938 DOI: 10.1038/s41467-024-53173-w] [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: 08/02/2023] [Accepted: 10/02/2024] [Indexed: 10/14/2024] Open
Abstract
Animals rely on compensatory actions to maintain stability and navigate their environment efficiently. These actions depend on global visual motion cues known as optic-flow. While the optomotor response has been the traditional focus for studying optic-flow compensation in insects, its simplicity has been insufficient to determine the role of the intricate optic-flow processing network involved in visual course control. Here, we reveal a series of course control behaviours in Drosophila and link them to specific neural circuits. We show that bilateral electrical coupling of optic-flow-sensitive neurons in the fly's lobula plate are required for a proper course control. This electrical interaction works alongside chemical synapses within the HS-H2 network to control the dynamics and direction of turning behaviours. Our findings reveal how insects use bilateral motion cues for navigation, assigning a new functional significance to the HS-H2 network and suggesting a previously unknown role for gap junctions in non-linear operations.
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Affiliation(s)
- Victoria O Pokusaeva
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Roshan Satapathy
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Olga Symonova
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Maximilian Joesch
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.
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7
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Gür B, Ramirez L, Cornean J, Thurn F, Molina-Obando S, Ramos-Traslosheros G, Silies M. Neural pathways and computations that achieve stable contrast processing tuned to natural scenes. Nat Commun 2024; 15:8580. [PMID: 39362859 PMCID: PMC11450186 DOI: 10.1038/s41467-024-52724-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 09/18/2024] [Indexed: 10/05/2024] Open
Abstract
Natural scenes are highly dynamic, challenging the reliability of visual processing. Yet, humans and many animals perform accurate visual behaviors, whereas computer vision devices struggle with rapidly changing background luminance. How does animal vision achieve this? Here, we reveal the algorithms and mechanisms of rapid luminance gain control in Drosophila, resulting in stable visual processing. We identify specific transmedullary neurons as the site of luminance gain control, which pass this property to direction-selective cells. The circuitry further involves wide-field neurons, matching computational predictions that local spatial pooling drive optimal contrast processing in natural scenes when light conditions change rapidly. Experiments and theory argue that a spatially pooled luminance signal achieves luminance gain control via divisive normalization. This process relies on shunting inhibition using the glutamate-gated chloride channel GluClα. Our work describes how the fly robustly processes visual information in dynamically changing natural scenes, a common challenge of all visual systems.
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Affiliation(s)
- Burak Gür
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
- The Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland
| | - Luisa Ramirez
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Jacqueline Cornean
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Freya Thurn
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Sebastian Molina-Obando
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Giordano Ramos-Traslosheros
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Marion Silies
- Institute of Developmental Biology and Neurobiology, Johannes-Gutenberg University Mainz, Mainz, Germany.
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8
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Nyberg KG, Navales FG, Keles E, Nguyen JQ, Hertz LM, Carthew RW. Robust and heritable knockdown of gene expression using a self-cleaving ribozyme in Drosophila. Genetics 2024; 227:iyae067. [PMID: 38701221 PMCID: PMC11304983 DOI: 10.1093/genetics/iyae067] [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: 01/19/2024] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 05/05/2024] Open
Abstract
The current toolkit for genetic manipulation in the model animal Drosophila melanogaster is extensive and versatile but not without its limitations. Here, we report a powerful and heritable method to knockdown gene expression in D. melanogaster using the self-cleaving N79 hammerhead ribozyme, a modification of a naturally occurring ribozyme found in the parasite Schistosoma mansoni. A 111-bp ribozyme cassette, consisting of the N79 ribozyme surrounded by insulating spacer sequences, was inserted into 4 independent long noncoding RNA genes as well as the male-specific splice variant of doublesex using scarless CRISPR/Cas9-mediated genome editing. Ribozyme-induced RNA cleavage resulted in robust destruction of 3' fragments typically exceeding 90%. Single molecule RNA fluorescence in situ hybridization results suggest that cleavage and destruction can even occur for nascent transcribing RNAs. Knockdown was highly specific to the targeted RNA, with no adverse effects observed in neighboring genes or the other splice variants. To control for potential effects produced by the simple insertion of 111 nucleotides into genes, we tested multiple catalytically inactive ribozyme variants and found that a variant with scrambled N79 sequence best recapitulated natural RNA levels. Thus, self-cleaving ribozymes offer a novel approach for powerful gene knockdown in Drosophila, with potential applications for the study of noncoding RNAs, nuclear-localized RNAs, and specific splice variants of protein-coding genes.
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Affiliation(s)
- Kevin G Nyberg
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Fritz Gerald Navales
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Eren Keles
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Joseph Q Nguyen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura M Hertz
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Richard W Carthew
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- NSF-Simons National Institute for Theory and Mathematics in Biology, Evanston, IL 60208, USA
- NSF-Simons Center for Quantitative Biology, Evanston, IL 60208, USA
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9
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Diao F, Vasudevan D, Heckscher ES, White BH. Hox gene-specific cellular targeting using split intein Trojan exons. Proc Natl Acad Sci U S A 2024; 121:e2317083121. [PMID: 38602904 PMCID: PMC11047080 DOI: 10.1073/pnas.2317083121] [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: 10/07/2023] [Accepted: 03/07/2024] [Indexed: 04/13/2024] Open
Abstract
The Trojan exon method, which makes use of intronically inserted T2A-Gal4 cassettes, has been widely used in Drosophila to create thousands of gene-specific Gal4 driver lines. These dual-purpose lines provide genetic access to specific cell types based on their expression of a native gene while simultaneously mutating one allele of the gene to enable loss-of-function analysis in homozygous animals. While this dual use is often an advantage, the truncation mutations produced by Trojan exons are sometimes deleterious in heterozygotes, perhaps by creating translation products with dominant negative effects. Such mutagenic effects can cause developmental lethality as has been observed with genes encoding essential transcription factors. Given the importance of transcription factors in specifying cell type, alternative techniques for generating specific Gal4 lines that target them are required. Here, we introduce a modified Trojan exon method that retains the targeting fidelity and plug-and-play modularity of the original method but mitigates its mutagenic effects by exploiting the self-splicing capabilities of split inteins. "Split Intein Trojan exons" (siTrojans) ensure that the two truncation products generated from the interrupted allele of the native gene are trans-spliced to create a full-length native protein. We demonstrate the efficacy of siTrojans by generating a comprehensive toolkit of Gal4 and Split Gal4 lines for the segmentally expressed Hox transcription factors and illustrate their use in neural circuit mapping by targeting neurons according to their position along the anterior-posterior axis. Both the method and the Hox gene-specific toolkit introduced here should be broadly useful.
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Affiliation(s)
- Fengqiu Diao
- Laboratory of Molecular Biology, Section on Neural Function, National Institute of Mental Health, NIH, Bethesda, MD20892
| | - Deeptha Vasudevan
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL60637
| | - Ellie S. Heckscher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL60637
| | - Benjamin H. White
- Laboratory of Molecular Biology, Section on Neural Function, National Institute of Mental Health, NIH, Bethesda, MD20892
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10
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Merrill CB, Titos I, Pabon MA, Montgomery AB, Rodan AR, Rothenfluh A. Iterative assay for transposase-accessible chromatin by sequencing to isolate functionally relevant neuronal subtypes. SCIENCE ADVANCES 2024; 10:eadi4393. [PMID: 38536919 PMCID: PMC10971406 DOI: 10.1126/sciadv.adi4393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 02/21/2024] [Indexed: 04/18/2024]
Abstract
The Drosophila brain contains tens of thousands of distinct cell types. Thousands of different transgenic lines reproducibly target specific neuron subsets, yet most still express in several cell types. Furthermore, most lines were developed without a priori knowledge of where the transgenes would be expressed. To aid in the development of cell type-specific tools for neuronal identification and manipulation, we developed an iterative assay for transposase-accessible chromatin (ATAC) approach. Open chromatin regions (OCRs) enriched in neurons, compared to whole bodies, drove transgene expression preferentially in subsets of neurons. A second round of ATAC-seq from these specific neuron subsets revealed additional enriched OCR2s that further restricted transgene expression within the chosen neuron subset. This approach allows for continued refinement of transgene expression, and we used it to identify neurons relevant for sleep behavior. Furthermore, this approach is widely applicable to other cell types and to other organisms.
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Affiliation(s)
- Collin B. Merrill
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
| | - Iris Titos
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
| | - Miguel A. Pabon
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Aylin R. Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Medical Service, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT 84108, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA
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11
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Wani AR, Chowdhury B, Luong J, Chaya GM, Patel K, Isaacman-Beck J, Shafer O, Kayser MS, Syed MH. Stem cell-specific ecdysone signaling regulates the development and function of a Drosophila sleep homeostat. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.560022. [PMID: 37873323 PMCID: PMC10592846 DOI: 10.1101/2023.09.29.560022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Complex behaviors arise from neural circuits that are assembled from diverse cell types. Sleep is a conserved and essential behavior, yet little is known regarding how the nervous system generates neuron types of the sleep-wake circuit. Here, we focus on the specification of Drosophila sleep-promoting neurons-long-field tangential input neurons that project to the dorsal layers of the fan-shaped body neuropil in the central complex (CX). We use lineage analysis and genetic birth dating to identify two bilateral Type II neural stem cells that generate these dorsal fan-shaped body (dFB) neurons. We show that adult dFB neurons express Ecdysone-induced protein E93, and loss of Ecdysone signaling or E93 in Type II NSCs results in the misspecification of the adult dFB neurons. Finally, we show that E93 knockdown in Type II NSCs affects adult sleep behavior. Our results provide insight into how extrinsic hormonal signaling acts on NSCs to generate neuronal diversity required for adult sleep behavior. These findings suggest that some adult sleep disorders might derive from defects in stem cell-specific temporal neurodevelopmental programs.
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Affiliation(s)
- Adil R Wani
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | - Budhaditya Chowdhury
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA
| | - Jenny Luong
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gonzalo Morales Chaya
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | - Krishna Patel
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
| | | | - Orie Shafer
- The Advanced Science Research Center, City University of New York, New York, NY 10031, USA
| | - Matthew S. Kayser
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mubarak Hussain Syed
- Neural Diversity Lab, Department of Biology, University of New Mexico, 219 Yale Blvd Ne, 87131 Albuquerque, NM, USA
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12
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Currier TA, Pang MM, Clandinin TR. Visual processing in the fly, from photoreceptors to behavior. Genetics 2023; 224:iyad064. [PMID: 37128740 PMCID: PMC10213501 DOI: 10.1093/genetics/iyad064] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/22/2023] [Indexed: 05/03/2023] Open
Abstract
Originally a genetic model organism, the experimental use of Drosophila melanogaster has grown to include quantitative behavioral analyses, sophisticated perturbations of neuronal function, and detailed sensory physiology. A highlight of these developments can be seen in the context of vision, where pioneering studies have uncovered fundamental and generalizable principles of sensory processing. Here we begin with an overview of vision-guided behaviors and common methods for probing visual circuits. We then outline the anatomy and physiology of brain regions involved in visual processing, beginning at the sensory periphery and ending with descending motor control. Areas of focus include contrast and motion detection in the optic lobe, circuits for visual feature selectivity, computations in support of spatial navigation, and contextual associative learning. Finally, we look to the future of fly visual neuroscience and discuss promising topics for further study.
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Affiliation(s)
- Timothy A Currier
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michelle M Pang
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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13
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Parisi MJ, Aimino MA, Mosca TJ. A conditional strategy for cell-type-specific labeling of endogenous excitatory synapses in Drosophila. CELL REPORTS METHODS 2023; 3:100477. [PMID: 37323572 PMCID: PMC10261928 DOI: 10.1016/j.crmeth.2023.100477] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/28/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023]
Abstract
Chemical neurotransmission occurs at specialized contacts where neurotransmitter release machinery apposes neurotransmitter receptors to underlie circuit function. A series of complex events underlies pre- and postsynaptic protein recruitment to neuronal connections. To better study synaptic development in individual neurons, we need cell-type-specific strategies to visualize endogenous synaptic proteins. Although presynaptic strategies exist, postsynaptic proteins remain less studied because of a paucity of cell-type-specific reagents. To study excitatory postsynapses with cell-type specificity, we engineered dlg1[4K], a conditionally labeled marker of Drosophila excitatory postsynaptic densities. With binary expression systems, dlg1[4K] labels central and peripheral postsynapses in larvae and adults. Using dlg1[4K], we find that distinct rules govern postsynaptic organization in adult neurons, multiple binary expression systems can concurrently label pre- and postsynapse in a cell-type-specific manner, and neuronal DLG1 can sometimes localize presynaptically. These results validate our strategy for conditional postsynaptic labeling and demonstrate principles of synaptic organization.
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Affiliation(s)
- Michael J. Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael A. Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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14
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Zhang Y, Lowe S, Ding AZ, Li X. Notch-dependent binary fate choice regulates the Netrin pathway to control axon guidance of Drosophila visual projection neurons. Cell Rep 2023; 42:112143. [PMID: 36821442 PMCID: PMC10124989 DOI: 10.1016/j.celrep.2023.112143] [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: 01/13/2022] [Revised: 10/22/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
Notch-dependent binary fate choice between sister neurons is one of the mechanisms to generate neural diversity. How these upstream neural fate specification programs regulate downstream effector genes to control axon targeting and neuropil assembly remains less well understood. Here, we report that Notch-dependent binary fate choice in Drosophila medulla neurons is required to regulate the Netrin axon guidance pathway, which controls targeting of transmedullary (Tm) neurons to lobula. In medulla neurons of Notch-on hemilineage composed of mostly lobula-targeting neurons, Notch signaling is required to activate the expression of Netrin-B and repress the expression of its repulsive receptor Unc-5. Turning off Unc-5 is necessary for Tm neurons to target lobula. Furthermore, Netrin-B provided by Notch-on medulla neurons is required for correct targeting of Tm axons from later-generated medulla columns. Thus, the coordinate regulation of Netrin pathway components by Notch signaling ensures correct targeting of Tm axons and contributes to the neuropil assembly.
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Affiliation(s)
- Yu Zhang
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Scott Lowe
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Andrew Z Ding
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Xin Li
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
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15
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Li L, Liu H, Qian KY, Nurrish S, Zeng XT, Zeng WX, Wang J, Kaplan JM, Tong XJ, Hu Z. CASK and FARP localize two classes of post-synaptic ACh receptors thereby promoting cholinergic transmission. PLoS Genet 2022; 18:e1010211. [PMID: 36279278 PMCID: PMC9632837 DOI: 10.1371/journal.pgen.1010211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 11/03/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Changes in neurotransmitter receptor abundance at post-synaptic elements play a pivotal role in regulating synaptic strength. For this reason, there is significant interest in identifying and characterizing the scaffolds required for receptor localization at different synapses. Here we analyze the role of two C. elegans post-synaptic scaffolding proteins (LIN-2/CASK and FRM-3/FARP) at cholinergic neuromuscular junctions. Constitutive knockouts or muscle specific inactivation of lin-2 and frm-3 dramatically reduced spontaneous and evoked post-synaptic currents. These synaptic defects resulted from the decreased abundance of two classes of post-synaptic ionotropic acetylcholine receptors (ACR-16/CHRNA7 and levamisole-activated AChRs). LIN-2's AChR scaffolding function is mediated by its SH3 and PDZ domains, which interact with AChRs and FRM-3/FARP, respectively. Thus, our findings show that post-synaptic LIN-2/FRM-3 complexes promote cholinergic synaptic transmission by recruiting AChRs to post-synaptic elements.
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Affiliation(s)
- Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
| | - Kang-Ying Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Stephen Nurrish
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xian-Ting Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wan-Xin Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jiafan Wang
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
| | - Joshua M. Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xia-Jing Tong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, Australia
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16
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Gonzalez-Suarez AD, Zavatone-Veth JA, Chen J, Matulis CA, Badwan BA, Clark DA. Excitatory and inhibitory neural dynamics jointly tune motion detection. Curr Biol 2022; 32:3659-3675.e8. [PMID: 35868321 PMCID: PMC9474608 DOI: 10.1016/j.cub.2022.06.075] [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: 01/09/2022] [Revised: 05/03/2022] [Accepted: 06/24/2022] [Indexed: 11/26/2022]
Abstract
Neurons integrate excitatory and inhibitory signals to produce their outputs, but the role of input timing in this integration remains poorly understood. Motion detection is a paradigmatic example of this integration, since theories of motion detection rely on different delays in visual signals. These delays allow circuits to compare scenes at different times to calculate the direction and speed of motion. Different motion detection circuits have different velocity sensitivity, but it remains untested how the response dynamics of individual cell types drive this tuning. Here, we sped up or slowed down specific neuron types in Drosophila's motion detection circuit by manipulating ion channel expression. Altering the dynamics of individual neuron types upstream of motion detectors increased their sensitivity to fast or slow visual motion, exposing distinct roles for excitatory and inhibitory dynamics in tuning directional signals, including a role for the amacrine cell CT1. A circuit model constrained by functional data and anatomy qualitatively reproduced the observed tuning changes. Overall, these results reveal how excitatory and inhibitory dynamics together tune a canonical circuit computation.
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Affiliation(s)
| | - Jacob A Zavatone-Veth
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Juyue Chen
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA
| | | | - Bara A Badwan
- School of Engineering and Applied Science, Yale University, New Haven, CT 06511, USA
| | - Damon A Clark
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, New Haven, CT 06511, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA; Department of Neuroscience, Yale University, New Haven, CT 06511, USA.
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17
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Cunningham KL, Sauvola CW, Tavana S, Littleton JT. Regulation of presynaptic Ca 2+ channel abundance at active zones through a balance of delivery and turnover. eLife 2022; 11:78648. [PMID: 35833625 PMCID: PMC9352347 DOI: 10.7554/elife.78648] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/13/2022] [Indexed: 12/03/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) mediate Ca2+ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (Pr), a key presynaptic determinant of synaptic strength. Although biosynthesis, delivery, and recycling cooperate to establish AZ VGCC abundance, experimentally isolating these distinct regulatory processes has been difficult. Here, we describe how the AZ levels of cacophony (Cac), the sole VGCC-mediating synaptic transmission in Drosophila, are determined. We also analyzed the relationship between Cac, the conserved VGCC regulatory subunit α2δ, and the core AZ scaffold protein Bruchpilot (BRP) in establishing a functional AZ. We find that Cac and BRP are independently regulated at growing AZs, as Cac is dispensable for AZ formation and structural maturation, and BRP abundance is not limiting for Cac accumulation. Additionally, AZs stop accumulating Cac after an initial growth phase, whereas BRP levels continue to increase given extended developmental time. AZ Cac is also buffered against moderate increases or decreases in biosynthesis, whereas BRP lacks this buffering. To probe mechanisms that determine AZ Cac abundance, intravital FRAP and Cac photoconversion were used to separately measure delivery and turnover at individual AZs over a multi-day period. Cac delivery occurs broadly across the AZ population, correlates with AZ size, and is rate-limited by α2δ. Although Cac does not undergo significant lateral transfer between neighboring AZs over the course of development, Cac removal from AZs does occur and is promoted by new Cac delivery, generating a cap on Cac accumulation at mature AZs. Together, these findings reveal how Cac biosynthesis, synaptic delivery, and recycling set the abundance of VGCCs at individual AZs throughout synapse development and maintenance.
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Affiliation(s)
- Karen L Cunningham
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Chad W Sauvola
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Sara Tavana
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
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18
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Duhart JC, Mosca TJ. Genetic regulation of central synapse formation and organization in Drosophila melanogaster. Genetics 2022; 221:6597078. [PMID: 35652253 DOI: 10.1093/genetics/iyac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 01/04/2023] Open
Abstract
A goal of modern neuroscience involves understanding how connections in the brain form and function. Such a knowledge is essential to inform how defects in the exquisite complexity of nervous system growth influence neurological disease. Studies of the nervous system in the fruit fly Drosophila melanogaster enabled the discovery of a wealth of molecular and genetic mechanisms underlying development of synapses-the specialized cell-to-cell connections that comprise the essential substrate for information flow and processing in the nervous system. For years, the major driver of knowledge was the neuromuscular junction due to its ease of examination. Analogous studies in the central nervous system lagged due to a lack of genetic accessibility of specific neuron classes, synaptic labels compatible with cell-type-specific access, and high resolution, quantitative imaging strategies. However, understanding how central synapses form remains a prerequisite to understanding brain development. In the last decade, a host of new tools and techniques extended genetic studies of synapse organization into central circuits to enhance our understanding of synapse formation, organization, and maturation. In this review, we consider the current state-of-the-field. We first discuss the tools, technologies, and strategies developed to visualize and quantify synapses in vivo in genetically identifiable neurons of the Drosophila central nervous system. Second, we explore how these tools enabled a clearer understanding of synaptic development and organization in the fly brain and the underlying molecular mechanisms of synapse formation. These studies establish the fly as a powerful in vivo genetic model that offers novel insights into neural development.
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Affiliation(s)
- Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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19
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Gao L, Zhao J, Ardiel EL, Hall Q, Nurrish S, Kaplan JM. Shank promotes action potential repolarization by recruiting BK channels to calcium microdomains. eLife 2022; 11:75140. [PMID: 35266450 PMCID: PMC8937234 DOI: 10.7554/elife.75140] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
Mutations altering the scaffolding protein Shank are linked to several psychiatric disorders, and to synaptic and behavioral defects in mice. Among its many binding partners, Shank directly binds CaV1 voltage activated calcium channels. Here we show that the C. elegans SHN-1/Shank promotes CaV1 coupling to calcium activated potassium channels. Mutations inactivating SHN-1, and those preventing SHN-1 binding to EGL-19/CaV1 all increase action potential durations in body muscles. Action potential repolarization is mediated by two classes of potassium channels: SHK-1/KCNA and SLO-1 and SLO-2 BK channels. BK channels are calcium-dependent, and their activation requires tight coupling to EGL-19/CaV1 channels. SHN-1's effects on AP duration are mediated by changes in BK channels. In shn-1 mutants, SLO-2 currents and channel clustering are significantly decreased in both body muscles and neurons. Finally, increased and decreased shn-1 gene copy number produce similar changes in AP width and SLO-2 current. Collectively, these results suggest that an important function of Shank is to promote microdomain coupling of BK with CaV1.
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Affiliation(s)
- Luna Gao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Jian Zhao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Evan L Ardiel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Qi Hall
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Stephen Nurrish
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
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20
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A global timing mechanism regulates cell-type-specific wiring programmes. Nature 2022; 603:112-118. [PMID: 35197627 DOI: 10.1038/s41586-022-04418-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/10/2022] [Indexed: 01/04/2023]
Abstract
The assembly of neural circuits is dependent on precise spatiotemporal expression of cell recognition molecules1-5. Factors controlling cell type specificity have been identified6-8, but how timing is determined remains unknown. Here we describe induction of a cascade of transcription factors by a steroid hormone (ecdysone) in all fly visual system neurons spanning target recognition and synaptogenesis. We demonstrate through single-cell sequencing that the ecdysone pathway regulates the expression of a common set of targets required for synaptic maturation and cell-type-specific targets enriched for cell-surface proteins regulating wiring specificity. Transcription factors in the cascade regulate the expression of the same wiring genes in complex ways, including activation in one cell type and repression in another. We show that disruption of the ecdysone pathway generates specific defects in dendritic and axonal processes and synaptic connectivity, with the order of transcription factor expression correlating with sequential steps in wiring. We also identify shared targets of a cell-type-specific transcription factor and the ecdysone pathway that regulate specificity. We propose that neurons integrate a global temporal transcriptional module with cell-type-specific transcription factors to generate different cell-type-specific patterns of cell recognition molecules regulating wiring.
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21
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Leinwand SG, Scott K. Juvenile hormone drives the maturation of spontaneous mushroom body neural activity and learned behavior. Neuron 2021; 109:1836-1847.e5. [PMID: 33915110 DOI: 10.1016/j.neuron.2021.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/26/2021] [Accepted: 04/07/2021] [Indexed: 12/21/2022]
Abstract
Mature behaviors emerge from neural circuits sculpted by genetic programs and spontaneous and evoked neural activity. However, how neural activity is refined to drive maturation of learned behavior remains poorly understood. Here, we explore how transient hormonal signaling coordinates a neural activity state transition and maturation of associative learning. We identify spontaneous, asynchronous activity in a Drosophila learning and memory brain region, the mushroom body. This activity declines significantly over the first week of adulthood. Moreover, this activity is generated cell-autonomously via Cacophony voltage-gated calcium channels in a single cell type, α'/β' Kenyon cells. Juvenile hormone, a crucial developmental regulator, acts transiently in α'/β' Kenyon cells during a young adult sensitive period to downregulate spontaneous activity and enable subsequent enhanced learning. Hormone signaling in young animals therefore controls a neural activity state transition and is required for improved associative learning, providing insight into the maturation of circuits and behavior.
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Affiliation(s)
- Sarah G Leinwand
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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22
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Scaplen KM, Petruccelli E. Receptors and Channels Associated with Alcohol Use: Contributions from Drosophila. Neurosci Insights 2021; 16:26331055211007441. [PMID: 33870197 PMCID: PMC8020223 DOI: 10.1177/26331055211007441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 12/14/2022] Open
Abstract
Alcohol Use Disorder (AUD) is a debilitating disorder that manifests as problematic patterns of alcohol use. At the core of AUD's behavioral manifestations are the profound structural, physiological, cellular, and molecular effects of alcohol on the brain. While the field has made considerable progress in understanding the neuromolecular targets of alcohol we still lack a comprehensive understanding of alcohol's actions and effective treatment strategies. Drosophila melanogaster is a powerful model for investigating the neuromolecular targets of alcohol because flies model many of the core behavioral elements of AUD and offer a rich genetic toolkit to precisely reveal the in vivo molecular actions of alcohol. In this review, we focus on receptors and channels that are often targeted by alcohol within the brain. We discuss the general roles of these proteins, their role in alcohol-associated behaviors across species, and propose ways in which Drosophila models can help advance the field.
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Affiliation(s)
- Kristin M Scaplen
- Department of Psychology, Bryant University, Smithfield, RI, USA
- Center for Health and Behavioral Studies, Bryant University, Smithfield, RI, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Emily Petruccelli
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, USA
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23
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Keleş MF, Hardcastle BJ, Städele C, Xiao Q, Frye MA. Inhibitory Interactions and Columnar Inputs to an Object Motion Detector in Drosophila. Cell Rep 2021; 30:2115-2124.e5. [PMID: 32075756 DOI: 10.1016/j.celrep.2020.01.061] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/06/2019] [Accepted: 01/16/2020] [Indexed: 02/06/2023] Open
Abstract
The direction-selective T4/T5 cells innervate optic-flow processing projection neurons in the lobula plate of the fly that mediate the visual control of locomotion. In the lobula, visual projection neurons coordinate complex behavioral responses to visual features, however, the input circuitry and computations that bestow their feature-detecting properties are less clear. Here, we study a highly specialized small object motion detector, LC11, and demonstrate that its responses are suppressed by local background motion. We show that LC11 expresses GABA-A receptors that serve to sculpt responses to small objects but are not responsible for the rejection of background motion. Instead, LC11 is innervated by columnar T2 and T3 neurons that are themselves highly sensitive to small static or moving objects, insensitive to wide-field motion and, unlike T4/T5, respond to both ON and OFF luminance steps.
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Affiliation(s)
- Mehmet F Keleş
- University of California, Los Angeles, Department of Integrative Biology and Physiology, 610 Charles Young Drive East, Los Angeles, CA 90095-7239, USA
| | - Ben J Hardcastle
- University of California, Los Angeles, Department of Integrative Biology and Physiology, 610 Charles Young Drive East, Los Angeles, CA 90095-7239, USA
| | - Carola Städele
- University of California, Los Angeles, Department of Integrative Biology and Physiology, 610 Charles Young Drive East, Los Angeles, CA 90095-7239, USA
| | - Qi Xiao
- University of California, Los Angeles, Department of Integrative Biology and Physiology, 610 Charles Young Drive East, Los Angeles, CA 90095-7239, USA; University of California, Los Angeles, Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Mark A Frye
- University of California, Los Angeles, Department of Integrative Biology and Physiology, 610 Charles Young Drive East, Los Angeles, CA 90095-7239, USA.
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24
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Trivedi D. Using CRISPR-Cas9-based genome engineering tools in Drosophila melanogaster. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 180:85-121. [PMID: 33934839 DOI: 10.1016/bs.pmbts.2021.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Drosophila melanogaster has been used as a model organism for over a century. Mutant-based analyses have been used extensively to understand the genetic basis of different cellular processes, including development, neuronal function and diseases. Most of the earlier genetic mutants and specific tools were generated by random insertions and deletion strategies and then mapped to specific genomic loci. Since all genomic regions are not equally accessible to random mutations and insertions, many genes still remain uncharacterized. Low efficiency of targeted genomic manipulation approaches that rely on homologous recombination, and difficulty in generating resources for sequence-specific endonucleases, such as ZFNs (Zinc Finger Nucleases) and TALENs (Transcription Activator-Like Effector Nucleases), could not make these gene targeting techniques very popular. However, recently RNA directed DNA endonucleases, such as CRISPR-Cas, have transformed genome engineering owing to their comparative ease, versatility, and low expense. With the added advantage of preexisting genetic tools, CRISPR-Cas-based manipulations are being extensively used in Drosophila melanogaster and simultaneously being fine-tuned for specific experimental requirements. In this chapter, I will discuss various uses of CRISPR-Cas-based genetic engineering and specific design methods in Drosophila melanogaster. I will summarize various already available tools that are being utilized in conjunction with CRISPR-Cas technology to generate specific genetic manipulation and are being optimized to address specific questions. Finally, I will discuss the future directions of Drosophila genetics research and how CRISPR-Cas can be utilized to target specific questions, addressing which has not been possible thus far.
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Affiliation(s)
- Deepti Trivedi
- National Centre for Biological Sciences-TIFR, Bengaluru, India.
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25
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Driesschaert B, Mergan L, Temmerman L. Conditional gene expression in invertebrate animal models. J Genet Genomics 2021; 48:14-31. [PMID: 33814307 DOI: 10.1016/j.jgg.2021.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/11/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
A mechanistic understanding of biology requires appreciating spatiotemporal aspects of gene expression and its functional implications. Conditional expression allows for (ir)reversible switching of genes on or off, with the potential of spatial and/or temporal control. This provides a valuable complement to the more often used constitutive gene (in)activation through mutagenesis, providing tools to answer a wider array of research questions across biological disciplines. Spatial and/or temporal control are granted primarily by (combinations of) specific promoters, temperature regimens, compound addition, or illumination. The use of such genetic tool kits is particularly widespread in invertebrate animal models because they can be applied to study biological processes in short time frames and on large scales, using organisms amenable to easy genetic manipulation. Recent years witnessed an exciting expansion and optimization of such tools, of which we provide a comprehensive overview and discussion regarding their use in invertebrates. The mechanism, applicability, benefits, and drawbacks of each of the systems, as well as further developments to be expected in the foreseeable future, are highlighted.
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Affiliation(s)
- Brecht Driesschaert
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium
| | - Lucas Mergan
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium
| | - Liesbet Temmerman
- Animal Physiology and Neurobiology, Department of Biology, University of Leuven (KU Leuven), Naamsestraat 59 - Box 2465, B-3000 Leuven, Belgium.
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26
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Fendl S, Vieira RM, Borst A. Conditional protein tagging methods reveal highly specific subcellular distribution of ion channels in motion-sensing neurons. eLife 2020; 9:62953. [PMID: 33079061 PMCID: PMC7655108 DOI: 10.7554/elife.62953] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/14/2020] [Indexed: 11/25/2022] Open
Abstract
Neurotransmitter receptors and ion channels shape the biophysical properties of neurons, from the sign of the response mediated by neurotransmitter receptors to the dynamics shaped by voltage-gated ion channels. Therefore, knowing the localizations and types of receptors and channels present in neurons is fundamental to our understanding of neural computation. Here, we developed two approaches to visualize the subcellular localization of specific proteins in Drosophila: The flippase-dependent expression of GFP-tagged receptor subunits in single neurons and ‘FlpTag’, a versatile new tool for the conditional labelling of endogenous proteins. Using these methods, we investigated the subcellular distribution of the receptors GluClα, Rdl, and Dα7 and the ion channels para and Ih in motion-sensing T4/T5 neurons of the Drosophila visual system. We discovered a strictly segregated subcellular distribution of these proteins and a sequential spatial arrangement of glutamate, acetylcholine, and GABA receptors along the dendrite that matched the previously reported EM-reconstructed synapse distributions.
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Affiliation(s)
- Sandra Fendl
- Max Planck Institute of Neurobiology, Martinsried, Germany.,Graduate School of Systemic Neurosciences, LMU Munich, Martinsried, Germany
| | | | - Alexander Borst
- Max Planck Institute of Neurobiology, Martinsried, Germany.,Graduate School of Systemic Neurosciences, LMU Munich, Martinsried, Germany
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27
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Serotonergic modulation of visual neurons in Drosophila melanogaster. PLoS Genet 2020; 16:e1009003. [PMID: 32866139 PMCID: PMC7485980 DOI: 10.1371/journal.pgen.1009003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/11/2020] [Accepted: 07/22/2020] [Indexed: 02/06/2023] Open
Abstract
Sensory systems rely on neuromodulators, such as serotonin, to provide flexibility for information processing as stimuli vary, such as light intensity throughout the day. Serotonergic neurons broadly innervate the optic ganglia of Drosophila melanogaster, a widely used model for studying vision. It remains unclear whether serotonin modulates the physiology of interneurons in the optic ganglia. To address this question, we first mapped the expression patterns of serotonin receptors in the visual system, focusing on a subset of cells with processes in the first optic ganglion, the lamina. Serotonin receptor expression was found in several types of columnar cells in the lamina including 5-HT2B in lamina monopolar cell L2, required for spatiotemporal luminance contrast, and both 5-HT1A and 5-HT1B in T1 cells, whose function is unknown. Subcellular mapping with GFP-tagged 5-HT2B and 5-HT1A constructs indicated that these receptors localize to layer M2 of the medulla, proximal to serotonergic boutons, suggesting that the medulla neuropil is the primary site of serotonergic regulation for these neurons. Exogenous serotonin increased basal intracellular calcium in L2 terminals in layer M2 and modestly decreased the duration of visually induced calcium transients in L2 neurons following repeated dark flashes, but otherwise did not alter the calcium transients. Flies without functional 5-HT2B failed to show an increase in basal calcium in response to serotonin. 5-HT2B mutants also failed to show a change in amplitude in their response to repeated light flashes but other calcium transient parameters were relatively unaffected. While we did not detect serotonin receptor expression in L1 neurons, they, like L2, underwent serotonin-induced changes in basal calcium, presumably via interactions with other cells. These data demonstrate that serotonin modulates the physiology of interneurons involved in early visual processing in Drosophila. Serotonergic neurons innervate the Drosophila melanogaster eye, but it was not known whether serotonin signaling could induce acute physiological responses in visual interneurons. We found serotonin receptors expressed in all neuropils of the optic lobe and identified specific neurons involved in visual information processing that express serotonin receptors. Activation of these receptors increased intracellular calcium in first order interneurons L1 and L2 and may enhance visually induced calcium transients in L2 neurons. These data support a role for the serotonergic neuromodulation of interneurons in the Drosophila visual system.
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28
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Site-Specific Recombination with Inverted Target Sites: A Cautionary Tale of Dicentric and Acentric Chromosomes. Genetics 2020; 215:923-930. [PMID: 32586890 DOI: 10.1534/genetics.120.303394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/22/2020] [Indexed: 11/18/2022] Open
Abstract
Site-specific recombinases are widely used tools for analysis of genetics, development, and cell biology, and many schemes have been devised to alter gene expression by recombinase-mediated DNA rearrangements. Because the FRT and lox target sites for the commonly used FLP and Cre recombinases are asymmetrical, and must pair in the same direction to recombine, construct design must take into account orientation of the target sites. Both direct and inverted configurations have been used. However, the outcome of recombination between target sites on sister chromatids is frequently overlooked. This is especially consequential with inverted target sites, where exchange between oppositely oriented target sites on sisters will produce dicentric and acentric chromosomes. By using constructs that have inverted target sites in Drosophila melanogaster and in mice, we show here that dicentric chromosomes are produced in the presence of recombinase, and that the frequency of this event is quite high. The negative effects on cell viability and behavior can be significant, and should be considered when using such constructs.
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29
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Bernasek SM, Peláez N, Carthew RW, Bagheri N, Amaral LAN. Fly-QMA: Automated analysis of mosaic imaginal discs in Drosophila. PLoS Comput Biol 2020; 16:e1007406. [PMID: 32126077 PMCID: PMC7100978 DOI: 10.1371/journal.pcbi.1007406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 03/27/2020] [Accepted: 01/27/2020] [Indexed: 12/01/2022] Open
Abstract
Mosaic analysis provides a means to probe developmental processes in situ by generating loss-of-function mutants within otherwise wildtype tissues. Combining these techniques with quantitative microscopy enables researchers to rigorously compare RNA or protein expression across the resultant clones. However, visual inspection of mosaic tissues remains common in the literature because quantification demands considerable labor and computational expertise. Practitioners must segment cell membranes or cell nuclei from a tissue and annotate the clones before their data are suitable for analysis. Here, we introduce Fly-QMA, a computational framework that automates each of these tasks for confocal microscopy images of Drosophila imaginal discs. The framework includes an unsupervised annotation algorithm that incorporates spatial context to inform the genetic identity of each cell. We use a combination of real and synthetic validation data to survey the performance of the annotation algorithm across a broad range of conditions. By contributing our framework to the open-source software ecosystem, we aim to contribute to the current move toward automated quantitative analysis among developmental biologists.
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Affiliation(s)
- Sebastian M. Bernasek
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, United States of America
- NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, Illinois, United States of America
| | - Nicolás Peláez
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Richard W. Carthew
- NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, Illinois, United States of America
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- Department of Biochemistry and Molecular Genetics, Northwestern University, Evanston, Illinois, United States of America
| | - Neda Bagheri
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, United States of America
- NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, Illinois, United States of America
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- Department of Chemical Engineering, University of Washington, Seattle, Washington, United States of America
- Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois, United States of America
| | - Luís A. N. Amaral
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois, United States of America
- NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, Illinois, United States of America
- Northwestern Institute on Complex Systems, Northwestern University, Evanston, Illinois, United States of America
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois, United States of America
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30
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Kanca O, Zirin J, Garcia-Marques J, Knight SM, Yang-Zhou D, Amador G, Chung H, Zuo Z, Ma L, He Y, Lin WW, Fang Y, Ge M, Yamamoto S, Schulze KL, Hu Y, Spradling AC, Mohr SE, Perrimon N, Bellen HJ. An efficient CRISPR-based strategy to insert small and large fragments of DNA using short homology arms. eLife 2019; 8:e51539. [PMID: 31674908 PMCID: PMC6855806 DOI: 10.7554/elife.51539] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022] Open
Abstract
We previously reported a CRISPR-mediated knock-in strategy into introns of Drosophila genes, generating an attP-FRT-SA-T2A-GAL4-polyA-3XP3-EGFP-FRT-attP transgenic library for multiple uses (Lee et al., 2018a). The method relied on double stranded DNA (dsDNA) homology donors with ~1 kb homology arms. Here, we describe three new simpler ways to edit genes in flies. We create single stranded DNA (ssDNA) donors using PCR and add 100 nt of homology on each side of an integration cassette, followed by enzymatic removal of one strand. Using this method, we generated GFP-tagged proteins that mark organelles in S2 cells. We then describe two dsDNA methods using cheap synthesized donors flanked by 100 nt homology arms and gRNA target sites cloned into a plasmid. Upon injection, donor DNA (1 to 5 kb) is released from the plasmid by Cas9. The cassette integrates efficiently and precisely in vivo. The approach is fast, cheap, and scalable.
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Affiliation(s)
- Oguz Kanca
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Jonathan Zirin
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | | | - Shannon Marie Knight
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Donghui Yang-Zhou
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Gabriel Amador
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Hyunglok Chung
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Liwen Ma
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Yuchun He
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Wen-Wen Lin
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Ying Fang
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Ming Ge
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Shinya Yamamoto
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
| | - Karen L Schulze
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Yanhui Hu
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Allan C Spradling
- Department of EmbryologyHoward Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - Stephanie E Mohr
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Norbert Perrimon
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Hugo J Bellen
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
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31
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Molina-Obando S, Vargas-Fique JF, Henning M, Gür B, Schladt TM, Akhtar J, Berger TK, Silies M. ON selectivity in the Drosophila visual system is a multisynaptic process involving both glutamatergic and GABAergic inhibition. eLife 2019; 8:e49373. [PMID: 31535971 PMCID: PMC6845231 DOI: 10.7554/elife.49373] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/18/2019] [Indexed: 01/06/2023] Open
Abstract
Sensory systems sequentially extract increasingly complex features. ON and OFF pathways, for example, encode increases or decreases of a stimulus from a common input. This ON/OFF pathway split is thought to occur at individual synaptic connections through a sign-inverting synapse in one of the pathways. Here, we show that ON selectivity is a multisynaptic process in the Drosophila visual system. A pharmacogenetics approach demonstrates that both glutamatergic inhibition through GluClα and GABAergic inhibition through Rdl mediate ON responses. Although neurons postsynaptic to the glutamatergic ON pathway input L1 lose all responses in GluClα mutants, they are resistant to a cell-type-specific loss of GluClα. This shows that ON selectivity is distributed across multiple synapses, and raises the possibility that cell-type-specific manipulations might reveal similar strategies in other sensory systems. Thus, sensory coding is more distributed than predicted by simple circuit motifs, allowing for robust neural processing.
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Affiliation(s)
- Sebastian Molina-Obando
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
- European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-SocietyGöttingenGermany
- International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of GöttingenGöttingenGermany
| | - Juan Felipe Vargas-Fique
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
- European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-SocietyGöttingenGermany
- International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of GöttingenGöttingenGermany
| | - Miriam Henning
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
- European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-SocietyGöttingenGermany
| | - Burak Gür
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
- European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-SocietyGöttingenGermany
- International Max Planck Research School and Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences (GGNB) at the University of GöttingenGöttingenGermany
| | - T Moritz Schladt
- Department of Molecular Sensory SystemsCenter of Advanced European Studies and Research (caesar)BonnGermany
| | - Junaid Akhtar
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
| | - Thomas K Berger
- Department of Molecular Sensory SystemsCenter of Advanced European Studies and Research (caesar)BonnGermany
- Institute of Physiology and PathophysiologyPhilipps-Universität MarburgMarburgGermany
| | - Marion Silies
- Institute of Developmental Biology and NeurobiologyJohannes Gutenberg-Universität MainzMainzGermany
- European Neuroscience Institute Göttingen – A Joint Initiative of the University Medical Center Göttingen and the Max-Planck-SocietyGöttingenGermany
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32
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Abstract
The release of neurotransmitters from synaptic vesicles (SVs) at pre-synaptic release sites is the principle means by which information transfer between neurons occurs. Knowledge of the location of SVs within a neuron can thus provide valuable clues about the location of neurotransmitter release within a neuron and the downstream neurons to which a given neuron is connected, important information for understanding how neural circuits generate behavior. Here the development and characterization of four conditional tagged SV markers for Drosophila melanogaster is presented. This characterization includes evaluation of conditionality, specificity for SV localization, and sensitivity of detection in diverse neuron subtypes. These four SV markers are genome-edited variants of the synaptic vesicle-specific protein Rab3. They depend on either the B2 or FLP recombinases for conditionality, and incorporate GFP or mCherry fluorescent proteins, or FLAG or HA epitope tags, for detection.
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33
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Abstract
Understanding how activity patterns in specific neural circuits coordinate an animal’s behavior remains a key area of neuroscience research. Genetic tools and a brain of tractable complexity make Drosophila a premier model organism for these studies. Here, we review the wealth of reagents available to map and manipulate neuronal activity with light.
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34
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Abstract
Since the founding of Drosophila genetics by Thomas Hunt Morgan and his colleagues over 100 years ago, the experimental induction of mosaicism has featured prominently in its recognition as an unsurpassed genetic model organism. The use of genetic mosaics has facilitated the discovery of a wide variety of developmental processes, identified specific cell lineages, allowed the study of recessive embryonic lethal mutations, and demonstrated the existence of cell competition. Here, we discuss how genetic mosaicism in Drosophila became an invaluable research tool that revolutionized developmental biology. We describe the prevailing methods used to produce mosaic animals, and highlight advantages and disadvantages of each genetic system. We cover methods ranging from simple "twin-spot" analysis to more sophisticated systems of multicolor labeling.
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35
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Li-Kroeger D, Kanca O, Lee PT, Cowan S, Lee MT, Jaiswal M, Salazar JL, He Y, Zuo Z, Bellen HJ. An expanded toolkit for gene tagging based on MiMIC and scarless CRISPR tagging in Drosophila. eLife 2018; 7:e38709. [PMID: 30091705 PMCID: PMC6095692 DOI: 10.7554/elife.38709] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023] Open
Abstract
We generated two new genetic tools to efficiently tag genes in Drosophila. The first, Double Header (DH) utilizes intronic MiMIC/CRIMIC insertions to generate artificial exons for GFP mediated protein trapping or T2A-GAL4 gene trapping in vivo based on Cre recombinase to avoid embryo injections. DH significantly increases integration efficiency compared to previous strategies and faithfully reports the expression pattern of genes and proteins. The second technique targets genes lacking coding introns using a two-step cassette exchange. First, we replace the endogenous gene with an excisable compact dominant marker using CRISPR making a null allele. Second, the insertion is replaced with a protein::tag cassette. This sequential manipulation allows the generation of numerous tagged alleles or insertion of other DNA fragments that facilitates multiple downstream applications. Both techniques allow precise gene manipulation and facilitate detection of gene expression, protein localization and assessment of protein function, as well as numerous other applications.
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Affiliation(s)
- David Li-Kroeger
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Oguz Kanca
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Pei-Tseng Lee
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Sierra Cowan
- Department of Biochemistry and Cell BiologyRice University HoustonHoustonUnited States
| | - Michael T Lee
- Department of Biochemistry and Cell BiologyRice University HoustonHoustonUnited States
| | - Manish Jaiswal
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical InstituteBaylor College of MedicineHoustonUnited States
| | - Jose Luis Salazar
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Yuchun He
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical InstituteBaylor College of MedicineHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Hugo J Bellen
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical InstituteBaylor College of MedicineHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research InstituteHoustonUnited States
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36
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Abstract
Motion in the visual world provides critical information to guide the behavior of sighted animals. Furthermore, as visual motion estimation requires comparisons of signals across inputs and over time, it represents a paradigmatic and generalizable neural computation. Focusing on the Drosophila visual system, where an explosion of technological advances has recently accelerated experimental progress, we review our understanding of how, algorithmically and mechanistically, motion signals are first computed.
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Affiliation(s)
- Helen H Yang
- Department of Neurobiology, Stanford University, Stanford, California 94305, USA; .,Current affiliation: Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University, Stanford, California 94305, USA;
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37
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Şentürk M, Bellen HJ. Genetic strategies to tackle neurological diseases in fruit flies. Curr Opin Neurobiol 2018; 50:24-32. [PMID: 29128849 PMCID: PMC5940587 DOI: 10.1016/j.conb.2017.10.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 10/13/2017] [Accepted: 10/17/2017] [Indexed: 10/18/2022]
Abstract
Drosophila melanogaster is a genetic model organism that has contributed to the discovery of numerous genes whose human homologues are associated with diseases. The development of sophisticated genetic tools to manipulate its genome accelerates the discovery of the genetic basis of undiagnosed human diseases and the elucidation of molecular pathogenic events of known and novel diseases. Here, we discuss various approaches used in flies to assess the function of the fly homologues of disease-associated genes. We highlight how systematic and combinatorial approaches based on recently established methods provide us with integrated tool sets that can be applied to the study of neurodevelopmental and neurodegenerative disorders.
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Affiliation(s)
- Mümine Şentürk
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston TX 77030, USA; Department of Neuroscience, BCM, Houston TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA.
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38
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Constance WD, Mukherjee A, Fisher YE, Pop S, Blanc E, Toyama Y, Williams DW. Neurexin and Neuroligin-based adhesion complexes drive axonal arborisation growth independent of synaptic activity. eLife 2018; 7:31659. [PMID: 29504935 PMCID: PMC5869020 DOI: 10.7554/elife.31659] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 03/04/2018] [Indexed: 11/25/2022] Open
Abstract
Building arborisations of the right size and shape is fundamental for neural network function. Live imaging in vertebrate brains strongly suggests that nascent synapses are critical for branch growth during development. The molecular mechanisms underlying this are largely unknown. Here we present a novel system in Drosophila for studying the development of complex arborisations live, in vivo during metamorphosis. In growing arborisations we see branch dynamics and localisations of presynaptic proteins very similar to the ‘synaptotropic growth’ described in fish/frogs. These accumulations of presynaptic proteins do not appear to be presynaptic release sites and are not paired with neurotransmitter receptors. Knockdowns of either evoked or spontaneous neurotransmission do not impact arbor growth. Instead, we find that axonal branch growth is regulated by dynamic, focal localisations of Neurexin and Neuroligin. These adhesion complexes provide stability for filopodia by a ‘stick-and-grow’ based mechanism wholly independent of synaptic activity.
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Affiliation(s)
- William D Constance
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom.,King's-NUS Joint Studentship Program, King's College London, London, United Kingdom
| | - Amrita Mukherjee
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Yvette E Fisher
- Department of Neurobiology, Stanford University, Stanford, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Sinziana Pop
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Eric Blanc
- Berlin Institute of Health, Berlin, Germany
| | - Yusuke Toyama
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Temasek Life Sciences Laboratory, Singapore, Singapore.,Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Darren W Williams
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom
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39
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Kanca O, Bellen HJ, Schnorrer F. Gene Tagging Strategies To Assess Protein Expression, Localization, and Function in Drosophila. Genetics 2017; 207:389-412. [PMID: 28978772 PMCID: PMC5629313 DOI: 10.1534/genetics.117.199968] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/13/2017] [Indexed: 01/15/2023] Open
Abstract
Analysis of gene function in complex organisms relies extensively on tools to detect the cellular and subcellular localization of gene products, especially proteins. Typically, immunostaining with antibodies provides these data. However, due to cost, time, and labor limitations, generating specific antibodies against all proteins of a complex organism is not feasible. Furthermore, antibodies do not enable live imaging studies of protein dynamics. Hence, tagging genes with standardized immunoepitopes or fluorescent tags that permit live imaging has become popular. Importantly, tagging genes present in large genomic clones or at their endogenous locus often reports proper expression, subcellular localization, and dynamics of the encoded protein. Moreover, these tagging approaches allow the generation of elegant protein removal strategies, standardization of visualization protocols, and permit protein interaction studies using mass spectrometry. Here, we summarize available genomic resources and techniques to tag genes and discuss relevant applications that are rarely, if at all, possible with antibodies.
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Affiliation(s)
- Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
- Howard Hughes Medical Institute, Houston, Texas 77030
| | - Frank Schnorrer
- Developmental Biology Institute of Marseille (IBDM), UMR 7288, CNRS, Aix-Marseille Université, 13288, France
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40
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Haag J, Mishra A, Borst A. A common directional tuning mechanism of Drosophila motion-sensing neurons in the ON and in the OFF pathway. eLife 2017; 6:29044. [PMID: 28829040 PMCID: PMC5582866 DOI: 10.7554/elife.29044] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/21/2017] [Indexed: 01/19/2023] Open
Abstract
In the fruit fly optic lobe, T4 and T5 cells represent the first direction-selective neurons, with T4 cells responding selectively to moving brightness increments (ON) and T5 cells to brightness decrements (OFF). Both T4 and T5 cells comprise four subtypes with directional tuning to one of the four cardinal directions. We had previously found that upward-sensitive T4 cells implement both preferred direction enhancement and null direction suppression (Haag et al., 2016). Here, we asked whether this mechanism generalizes to OFF-selective T5 cells and to all four subtypes of both cell classes. We found that all four subtypes of both T4 and T5 cells implement both mechanisms, that is preferred direction enhancement and null direction inhibition, on opposing sides of their receptive fields. This gives rise to the high degree of direction selectivity observed in both T4 and T5 cells within each subpopulation.
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Affiliation(s)
- Juergen Haag
- Max-Planck-Institute of Neurobiology, Martinsried, Germany
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Nagarkar-Jaiswal S, Manivannan SN, Zuo Z, Bellen HJ. A cell cycle-independent, conditional gene inactivation strategy for differentially tagging wild-type and mutant cells. eLife 2017; 6. [PMID: 28561736 PMCID: PMC5493436 DOI: 10.7554/elife.26420] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/25/2017] [Indexed: 12/14/2022] Open
Abstract
Here, we describe a novel method based on intronic MiMIC insertions described in Nagarkar-Jaiswal et al. (2015) to perform conditional gene inactivation in Drosophila. Mosaic analysis in Drosophila cannot be easily performed in post-mitotic cells. We therefore, therefore, developed Flip-Flop, a flippase-dependent in vivo cassette-inversion method that marks wild-type cells with the endogenous EGFP-tagged protein, whereas mutant cells are marked with mCherry upon inversion. We document the ease and usefulness of this strategy in differential tagging of wild-type and mutant cells in mosaics. We use this approach to phenotypically characterize the loss of SNF4Aγ, encoding the γ subunit of the AMP Kinase complex. The Flip-Flop method is efficient and reliable, and permits conditional gene inactivation based on both spatial and temporal cues, in a cell cycle-, and developmental stage-independent fashion, creating a platform for systematic screens of gene function in developing and adult flies with unprecedented detail. DOI:http://dx.doi.org/10.7554/eLife.26420.001 The instructions needed to build and maintain cells in an organism are encoded in their DNA. There are many different cell types, and each type only needs a small portion of the information found in the DNA to do its job. Hence, only some of the instructions, in the form of genes, need to be active or ‘expressed’ in any given cell type. To understand how a gene works, it is necessary to know in which cell the gene is expressed and where in the cell the gene product – normally a protein – is located. Researchers may study a gene by deleting it, which prevents the protein from being made, or by attaching a new instruction into the gene, which generates a fluorescent tag on the protein to determine where and when it is expressed. Until now, it was not possible to selectively inactivate a gene and simultaneously mark both normal cells containing the protein and mutant cells lacking the protein. Based on an existing tagging approach, Nagarkar-Jaiswal et al. have now developed a method in which normal and mutant cells of fruit flies are marked differently. A gene of interest is tagged with a fluorescent marker called green fluorescent protein (or GFP). The same gene is then inactivated in some of the cells, which are tagged with a red marker called mCherry. Nagarkar-Jaiswal et al. compared normal and mutant cells, and were able to determine how long it takes before the mutant cells become abnormal. With this new method, the role of numerous genes in any tissue of adult flies can be reassessed. This will allow to investigate what happens when a protein is removed in specific cells in adult flies. A future goal will be to apply this method to other animals that are more closely related to humans, such as mice, to gain a clearer picture of the role of genes in different cell types and how faulty genes may cause disease. DOI:http://dx.doi.org/10.7554/eLife.26420.002
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Affiliation(s)
| | - Sathiya N Manivannan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States
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