151
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Efficient Expression of Genes in the Drosophila Germline Using a UAS Promoter Free of Interference by Hsp70 piRNAs. Genetics 2018; 209:381-387. [PMID: 29669732 PMCID: PMC5972414 DOI: 10.1534/genetics.118.300874] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/12/2018] [Indexed: 11/23/2022] Open
Abstract
Using the yeast GAL4 transcription factor to control expression in Drosophila melanogaster has long been ineffective in female germ cells during oogenesis. Here, DeLuca and Spradling show that the expression problem of most Drosophila molecular tools... Controlling the expression of genes using a binary system involving the yeast GAL4 transcription factor has been a mainstay of Drosophila developmental genetics for nearly 30 years. However, most existing GAL4 expression constructs only function effectively in somatic cells, but not in germ cells during oogenesis, for unknown reasons. A special upstream activation sequence (UAS) promoter, UASp was created that does express during oogenesis, but the need to use different constructs for somatic and female germline cells has remained a significant technical limitation. Here, we show that the expression problem of UASt and many other Drosophila molecular tools in germline cells is caused by their core Hsp70 promoter sequences, which are targeted in female germ cells by Hsp70-directed Piwi-interacting RNAs (piRNAs) generated from endogenous Hsp70 gene sequences. In a genetic background lacking genomic Hsp70 genes and associated piRNAs, UASt-based constructs function effectively during oogenesis. By reducing Hsp70 sequences targeted by piRNAs, we created UASz, which functions better than UASp in the germline and like UASt in somatic cells.
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152
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Humberg TH, Bruegger P, Afonso B, Zlatic M, Truman JW, Gershow M, Samuel A, Sprecher SG. Dedicated photoreceptor pathways in Drosophila larvae mediate navigation by processing either spatial or temporal cues. Nat Commun 2018; 9:1260. [PMID: 29593252 PMCID: PMC5871836 DOI: 10.1038/s41467-018-03520-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 02/21/2018] [Indexed: 11/09/2022] Open
Abstract
To integrate changing environmental cues with high spatial and temporal resolution is critical for animals to orient themselves. Drosophila larvae show an effective motor program to navigate away from light sources. How the larval visual circuit processes light stimuli to control navigational decision remains unknown. The larval visual system is composed of two sensory input channels, Rhodopsin5 (Rh5) and Rhodopsin6 (Rh6) expressing photoreceptors (PRs). We here characterize how spatial and temporal information are used to control navigation. Rh6-PRs are required to perceive temporal changes of light intensity during head casts, while Rh5-PRs are required to control behaviors that allow navigation in response to spatial cues. We characterize how distinct behaviors are modulated and identify parallel acting and converging features of the visual circuit. Functional features of the larval visual circuit highlight the principle of how early in a sensory circuit distinct behaviors may be computed by partly overlapping sensory pathways.
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Affiliation(s)
| | - Pascal Bruegger
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
| | - Bruno Afonso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, VA, USA
| | - Marta Zlatic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, VA, USA.,Department of Zoology, University of Cambridge, CB2 3EJ, Cambridge, UK
| | - James W Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, VA, USA
| | - Marc Gershow
- Department of Physics and Center for Neural Science, New York University, New York, 10003, NY, USA
| | - Aravinthan Samuel
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, 02138, MA, USA
| | - Simon G Sprecher
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland.
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153
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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: 26] [Impact Index Per Article: 4.3] [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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154
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Zandawala M, Marley R, Davies SA, Nässel DR. Characterization of a set of abdominal neuroendocrine cells that regulate stress physiology using colocalized diuretic peptides in Drosophila. Cell Mol Life Sci 2018; 75:1099-1115. [PMID: 29043393 PMCID: PMC5814475 DOI: 10.1007/s00018-017-2682-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 10/01/2017] [Accepted: 10/06/2017] [Indexed: 12/24/2022]
Abstract
Multiple neuropeptides are known to regulate water and ion balance in Drosophila melanogaster. Several of these peptides also have other functions in physiology and behavior. Examples are corticotropin-releasing factor-like diuretic hormone (diuretic hormone 44; DH44) and leucokinin (LK), both of which induce fluid secretion by Malpighian tubules (MTs), but also regulate stress responses, feeding, circadian activity and other behaviors. Here, we investigated the functional relations between the LK and DH44 signaling systems. DH44 and LK peptides are only colocalized in a set of abdominal neurosecretory cells (ABLKs). Targeted knockdown of each of these peptides in ABLKs leads to increased resistance to desiccation, starvation and ionic stress. Food ingestion is diminished by knockdown of DH44, but not LK, and water retention is increased by LK knockdown only. Thus, the two colocalized peptides display similar systemic actions, but differ with respect to regulation of feeding and body water retention. We also demonstrated that DH44 and LK have additive effects on fluid secretion by MTs. It is likely that the colocalized peptides are coreleased from ABLKs into the circulation and act on the tubules where they target different cell types and signaling systems to regulate diuresis and stress tolerance. Additional targets seem to be specific for each of the two peptides and subserve regulation of feeding and water retention. Our data suggest that the ABLKs and hormonal actions are sufficient for many of the known DH44 and LK functions, and that the remaining neurons in the CNS play other functional roles.
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Affiliation(s)
- Meet Zandawala
- Department of Zoology, Stockholm University, Stockholm, Sweden.
| | - Richard Marley
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Shireen A Davies
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Dick R Nässel
- Department of Zoology, Stockholm University, Stockholm, Sweden.
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155
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Gruntman E, Romani S, Reiser MB. Simple integration of fast excitation and offset, delayed inhibition computes directional selectivity in Drosophila. Nat Neurosci 2018; 21:250-257. [PMID: 29311742 PMCID: PMC5967973 DOI: 10.1038/s41593-017-0046-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023]
Abstract
A neuron that extracts directionally selective motion information from upstream signals lacking this selectivity must compare visual responses from spatially offset inputs. Distinguishing among prevailing algorithmic models for this computation requires measuring fast neuronal activity and inhibition. In the Drosophila melanogaster visual system, a fourth-order neuron-T4-is the first cell type in the ON pathway to exhibit directionally selective signals. Here we use in vivo whole-cell recordings of T4 to show that directional selectivity originates from simple integration of spatially offset fast excitatory and slow inhibitory inputs, resulting in a suppression of responses to the nonpreferred motion direction. We constructed a passive, conductance-based model of a T4 cell that accurately predicts the neuron's response to moving stimuli. These results connect the known circuit anatomy of the motion pathway to the algorithmic mechanism by which the direction of motion is computed.
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Affiliation(s)
- Eyal Gruntman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Sandro Romani
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
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156
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Garner SRC, Castellanos MC, Baillie KE, Lian T, Allan DW. Drosophila female-specific Ilp7 motoneurons are generated by Fruitless-dependent cell death in males and by a double-assurance survival role for Transformer in females. Development 2018; 145:dev.150821. [PMID: 29229771 DOI: 10.1242/dev.150821] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 11/13/2017] [Indexed: 01/03/2023]
Abstract
Female-specific Ilp7 neuropeptide-expressing motoneurons (FS-Ilp7 motoneurons) are required in Drosophila for oviduct function in egg laying. Here, we uncover cellular and genetic mechanisms underlying their female-specific generation. We demonstrate that programmed cell death (PCD) eliminates FS-Ilp7 motoneurons in males, and that this requires male-specific splicing of the sex-determination gene fruitless (fru) into the FruMC isoform. However, in females, fru alleles that only generate FruM isoforms failed to kill FS-Ilp7 motoneurons. This blockade of FruM-dependent PCD was not attributable to doublesex gene function but to a non-canonical role for transformer (tra), a gene encoding the RNA splicing activator that regulates female-specific splicing of fru and dsx transcripts. In both sexes, we show that Tra prevents PCD even when the FruM isoform is expressed. In addition, we found that FruMC eliminated FS-Ilp7 motoneurons in both sexes, but only when Tra was absent. Thus, FruMC-dependent PCD eliminates female-specific neurons in males, and Tra plays a double-assurance function in females to establish and reinforce the decision to generate female-specific neurons.
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Affiliation(s)
- Sarah Rose C Garner
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Monica C Castellanos
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Katherine E Baillie
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Tianshun Lian
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Douglas W Allan
- Department of Cellular and Physiological Sciences, University of British Columbia, 2420 Life Sciences Institute, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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157
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Roeske MJ, Camino EM, Grover S, Rebeiz M, Williams TM. Cis-regulatory evolution integrated the Bric-à-brac transcription factors into a novel fruit fly gene regulatory network. eLife 2018; 7. [PMID: 29297463 PMCID: PMC5752203 DOI: 10.7554/elife.32273] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/19/2017] [Indexed: 11/13/2022] Open
Abstract
Gene expression evolution through gene regulatory network (GRN) changes has gained appreciation as a driver of morphological evolution. However, understanding how GRNs evolve is hampered by finding relevant cis-regulatory element (CRE) mutations, and interpreting the protein-DNA interactions they alter. We investigated evolutionary changes in the duplicated Bric-à-brac (Bab) transcription factors and a key Bab target gene in a GRN underlying the novel dimorphic pigmentation of D. melanogaster and its relatives. It has remained uncertain how Bab was integrated within the pigmentation GRN. Here, we show that the ancestral transcription factor activity of Bab gained a role in sculpting sex-specific pigmentation through the evolution of binding sites in a CRE of the pigment-promoting yellow gene. This work demonstrates how a new trait can evolve by incorporating existing transcription factors into a GRN through CRE evolution, an evolutionary path likely to predominate newly evolved functions of transcription factors.
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Affiliation(s)
- Maxwell J Roeske
- Department of Biology, University of Dayton, Dayton, United States
| | - Eric M Camino
- Department of Biology, University of Dayton, Dayton, United States
| | - Sumant Grover
- Department of Biology, University of Dayton, Dayton, United States
| | - Mark Rebeiz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Thomas Michael Williams
- Department of Biology, University of Dayton, Dayton, United States.,Center for Tissue Regeneration and Engineering at Dayton, University of Dayton, Dayton, United States
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158
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Neural mechanisms underlying sensitivity to reverse-phi motion in the fly. PLoS One 2017; 12:e0189019. [PMID: 29261684 PMCID: PMC5737883 DOI: 10.1371/journal.pone.0189019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/18/2017] [Indexed: 01/18/2023] Open
Abstract
Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON- or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics.
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159
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Li M, Bui M, Yang T, Bowman CS, White BJ, Akbari OS. Germline Cas9 expression yields highly efficient genome engineering in a major worldwide disease vector, Aedes aegypti. Proc Natl Acad Sci U S A 2017; 114:E10540-E10549. [PMID: 29138316 PMCID: PMC5724270 DOI: 10.1073/pnas.1711538114] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The development of CRISPR/Cas9 technologies has dramatically increased the accessibility and efficiency of genome editing in many organisms. In general, in vivo germline expression of Cas9 results in substantially higher activity than embryonic injection. However, no transgenic lines expressing Cas9 have been developed for the major mosquito disease vector Aedes aegypti Here, we describe the generation of multiple stable, transgenic Ae. aegypti strains expressing Cas9 in the germline, resulting in dramatic improvements in both the consistency and efficiency of genome modifications using CRISPR. Using these strains, we disrupted numerous genes important for normal morphological development, and even generated triple mutants from a single injection. We have also managed to increase the rates of homology-directed repair by more than an order of magnitude. Given the exceptional mutagenic efficiency and specificity of the Cas9 strains we engineered, they can be used for high-throughput reverse genetic screens to help functionally annotate the Ae. aegypti genome. Additionally, these strains represent a step toward the development of novel population control technologies targeting Ae. aegypti that rely on Cas9-based gene drives.
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Affiliation(s)
- Ming Li
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Michelle Bui
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Ting Yang
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Christian S Bowman
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Bradley J White
- Department of Entomology, University of California, Riverside, CA 92521
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Omar S Akbari
- Department of Entomology, University of California, Riverside, CA 92521;
- Center for Disease Vector Research, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
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160
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Seki HA, Shirima DD, Courtney Mustaphi CJ, Marchant R, Munishi PKT. The impact of land use and land cover change on biodiversity within and adjacent to Kibasira Swamp in Kilombero Valley, Tanzania. Afr J Ecol 2017. [DOI: 10.1111/aje.12488] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hamidu A. Seki
- Department of Geography; Faculty of Humanities and Social Sciences; Mkwawa University College of Education; Iringa Tanzania
| | - Deo D. Shirima
- Department of Ecosystems and Conservation; College of Forestry, Wildlife and Tourism; Sokoine University of Agriculture; Morogoro Tanzania
| | | | - Rob Marchant
- Environment Department; York Institute for Tropical Ecosystems; University of York; York UK
| | - Pantaleo K. T. Munishi
- Department of Ecosystems and Conservation; College of Forestry, Wildlife and Tourism; Sokoine University of Agriculture; Morogoro Tanzania
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161
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A multiplexable TALE-based binary expression system for in vivo cellular interaction studies. Nat Commun 2017; 8:1663. [PMID: 29162808 PMCID: PMC5698491 DOI: 10.1038/s41467-017-01592-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/03/2017] [Indexed: 11/08/2022] Open
Abstract
Binary expression systems have revolutionised genetic research by enabling delivery of loss-of-function and gain-of-function transgenes with precise spatial-temporal resolution in vivo. However, at present, each existing platform relies on a defined exogenous transcription activator capable of binding a unique recognition sequence. Consequently, none of these technologies alone can be used to simultaneously target different tissues or cell types in the same organism. Here, we report a modular system based on programmable transcription activator-like effector (TALE) proteins, which enables parallel expression of multiple transgenes in spatially distinct tissues in vivo. Using endogenous enhancers coupled to TALE drivers, we demonstrate multiplexed orthogonal activation of several transgenes carrying cognate variable activating sequences (VAS) in distinct neighbouring cell types of the Drosophila central nervous system. Since the number of combinatorial TALE–VAS pairs is virtually unlimited, this platform provides an experimental framework for highly complex genetic manipulation studies in vivo. Binary expression systems enable researchers to deliver loss-of-function or gain-of-function transgenes with spatial-temporal resolution in vivo. Here, the authors present a programmable TALE-based system for multiplexed orthogonal activation of transgenes in Drosophila.
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162
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Kubrak OI, Lushchak OV, Zandawala M, Nässel DR. Systemic corazonin signalling modulates stress responses and metabolism in Drosophila. Open Biol 2017; 6:rsob.160152. [PMID: 27810969 PMCID: PMC5133436 DOI: 10.1098/rsob.160152] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/05/2016] [Indexed: 12/20/2022] Open
Abstract
Stress triggers cellular and systemic reactions in organisms to restore homeostasis. For instance, metabolic stress, experienced during starvation, elicits a hormonal response that reallocates resources to enable food search and readjustment of physiology. Mammalian gonadotropin-releasing hormone (GnRH) and its insect orthologue, adipokinetic hormone (AKH), are known for their roles in modulating stress-related behaviour. Here we show that corazonin (Crz), a peptide homologous to AKH/GnRH, also alters stress physiology in Drosophila. The Crz receptor (CrzR) is expressed in salivary glands and adipocytes of the liver-like fat body, and CrzR knockdown targeted simultaneously to both these tissues increases the fly's resistance to starvation, desiccation and oxidative stress, reduces feeding, alters expression of transcripts of Drosophila insulin-like peptides (DILPs), and affects gene expression in the fat body. Furthermore, in starved flies, CrzR-knockdown increases circulating and stored carbohydrates. Thus, our findings indicate that elevated systemic Crz signalling during stress coordinates increased food intake and diminished energy stores to regain metabolic homeostasis. Our study suggests that an ancient stress-peptide in Urbilateria evolved to give rise to present-day GnRH, AKH and Crz signalling systems.
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Affiliation(s)
- Olga I Kubrak
- Department of Zoology, Stockholm University, 10691 Stockholm, Sweden
| | - Oleh V Lushchak
- Department of Zoology, Stockholm University, 10691 Stockholm, Sweden
| | - Meet Zandawala
- Department of Zoology, Stockholm University, 10691 Stockholm, Sweden
| | - Dick R Nässel
- Department of Zoology, Stockholm University, 10691 Stockholm, Sweden
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163
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Sethi S, Wang JW. A versatile genetic tool for post-translational control of gene expression in Drosophila melanogaster. eLife 2017; 6:30327. [PMID: 29140243 PMCID: PMC5703639 DOI: 10.7554/elife.30327] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/14/2017] [Indexed: 01/15/2023] Open
Abstract
Several techniques have been developed to manipulate gene expression temporally in intact neural circuits. However, the applicability of current tools developed for in vivo studies in Drosophila is limited by their incompatibility with existing GAL4 lines and side effects on physiology and behavior. To circumvent these limitations, we adopted a strategy to reversibly regulate protein degradation with a small molecule by using a destabilizing domain (DD). We show that this system is effective across different tissues and developmental stages. We further show that this system can be used to control in vivo gene expression levels with low background, large dynamic range, and in a reversible manner without detectable side effects on the lifespan or behavior of the animal. Additionally, we engineered tools for chemically controlling gene expression (GAL80-DD) and recombination (FLP-DD). We demonstrate the applicability of this technology in manipulating neuronal activity and for high-efficiency sparse labeling of neuronal populations.
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Affiliation(s)
- Sachin Sethi
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Jing W Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, San Diego, United States
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164
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Plazaola-Sasieta H, Fernández-Pineda A, Zhu Q, Morey M. Untangling the wiring of the Drosophila visual system: developmental principles and molecular strategies. J Neurogenet 2017; 31:231-249. [DOI: 10.1080/01677063.2017.1391249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Haritz Plazaola-Sasieta
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Alejandra Fernández-Pineda
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Qi Zhu
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
| | - Marta Morey
- Department of Genetics, Microbiology and Statistics; School of Biology and Institute of Biomedicine of the University of Barcelona (IBUB), University of Barcelona, Barcelona, Spain
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165
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Transsynaptic Mapping of Second-Order Taste Neurons in Flies by trans-Tango. Neuron 2017; 96:783-795.e4. [PMID: 29107518 DOI: 10.1016/j.neuron.2017.10.011] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/30/2017] [Accepted: 10/05/2017] [Indexed: 12/27/2022]
Abstract
Mapping neural circuits across defined synapses is essential for understanding brain function. Here we describe trans-Tango, a technique for anterograde transsynaptic circuit tracing and manipulation. At the core of trans-Tango is a synthetic signaling pathway that is introduced into all neurons in the animal. This pathway converts receptor activation at the cell surface into reporter expression through site-specific proteolysis. Specific labeling is achieved by presenting a tethered ligand at the synapses of genetically defined neurons, thereby activating the pathway in their postsynaptic partners and providing genetic access to these neurons. We first validated trans-Tango in the Drosophila olfactory system and then implemented it in the gustatory system, where projections beyond the first-order receptor neurons are not fully characterized. We identified putative second-order neurons within the sweet circuit that include projection neurons targeting known neuromodulation centers in the brain. These experiments establish trans-Tango as a flexible platform for transsynaptic circuit analysis.
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166
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Hara C, Morishita K, Takayanagi-Kiya S, Mikami A, Uchino K, Sakurai T, Kanzaki R, Sezutsu H, Iwami M, Kiya T. Refinement of ectopic protein expression through the GAL4/UAS system in Bombyx mori: application to behavioral and developmental studies. Sci Rep 2017; 7:11795. [PMID: 28924263 PMCID: PMC5603595 DOI: 10.1038/s41598-017-12102-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/01/2017] [Indexed: 11/10/2022] Open
Abstract
Silkmoth, Bombyx mori, is one of the important model insects in which transgenic techniques and the GAL4/UAS system are applicable. However, due to cytotoxicity and low transactivation activity of GAL4, effectiveness of the GAL4/UAS system and its application in B. mori are still limited. In the present study, we refined the previously reported UAS vector by exploiting transcriptional and translational enhancers, and achieved 200-fold enhancement of reporter GFP fluorescence in the GAL4/UAS system. Enhanced protein expression of membrane-targeted GFP and calcium indicator protein (GCaMP5G) drastically improved visualization of fine neurite structures and neural activity, respectively. Also, with the refined system, we generated a transgenic strain that expresses tetanus toxin light chain (TeTxLC), which blocks synaptic transmission, under the control of GAL4. Ectopic TeTxLC expression in the sex pheromone receptor neurons inhibited male courtship behavior, proving effectiveness of TeTxLC on loss-of-function analyses of neural circuits. In addition, suppression of prothoracicotropic hormone (PTTH) or insulin-like peptide (bombyxin) secretion impaired developmental timing and growth rate, respectively. Furthermore, we revealed that larval growth is sex-differentially regulated by these peptide hormones. The present study provides important technical underpinnings of transgenic approaches in silkmoths and insights into mechanisms of postembryonic development in insects.
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Affiliation(s)
- Chiho Hara
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Koudai Morishita
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Seika Takayanagi-Kiya
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Akihisa Mikami
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Keiro Uchino
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Takeshi Sakurai
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan
| | - Hideki Sezutsu
- Transgenic Silkworm Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Masafumi Iwami
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan
| | - Taketoshi Kiya
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920-1192, Japan.
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167
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Shiozaki HM, Kazama H. Parallel encoding of recent visual experience and self-motion during navigation in Drosophila. Nat Neurosci 2017; 20:1395-1403. [PMID: 28869583 DOI: 10.1038/nn.4628] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 07/26/2017] [Indexed: 12/16/2022]
Abstract
Animal navigation requires multiple types of information for decisions on directional heading. We identified neural processing channels that encode multiple cues during navigational decision-making in Drosophila melanogaster. In a flight simulator, we found that flies made directional choices on the basis of the location of a recently presented landmark. This experience-guided navigation was impaired by silencing neurons in the bulb (BU), a region in the central brain. Two-photon calcium imaging during flight revealed that the dorsal part of the BU encodes the location of a recent landmark, whereas the ventral part of the BU tracks self-motion reflecting turns. Photolabeling-based circuit tracing indicated that these functional compartments of the BU constitute adjacent, yet distinct, anatomical pathways that both enter the navigation center. Thus, the fly's navigation system organizes multiple types of information in parallel channels, which may compactly transmit signals without interference for decision-making during flight.
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Affiliation(s)
| | - Hokto Kazama
- RIKEN Brain Science Institute, Saitama, Japan.,Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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168
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Watanabe K, Chiu H, Pfeiffer BD, Wong AM, Hoopfer ED, Rubin GM, Anderson DJ. A Circuit Node that Integrates Convergent Input from Neuromodulatory and Social Behavior-Promoting Neurons to Control Aggression in Drosophila. Neuron 2017; 95:1112-1128.e7. [PMID: 28858617 PMCID: PMC5588916 DOI: 10.1016/j.neuron.2017.08.017] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/06/2017] [Accepted: 08/09/2017] [Indexed: 01/08/2023]
Abstract
Diffuse neuromodulatory systems such as norepinephrine (NE) control brain-wide states such as arousal, but whether they control complex social behaviors more specifically is not clear. Octopamine (OA), the insect homolog of NE, is known to promote both arousal and aggression. We have performed a systematic, unbiased screen to identify OA receptor-expressing neurons (OARNs) that control aggression in Drosophila. Our results uncover a tiny population of male-specific aSP2 neurons that mediate a specific influence of OA on aggression, independent of any effect on arousal. Unexpectedly, these neurons receive convergent input from OA neurons and P1 neurons, a population of FruM+ neurons that promotes male courtship behavior. Behavioral epistasis experiments suggest that aSP2 neurons may constitute an integration node at which OAergic neuromodulation can bias the output of P1 neurons to favor aggression over inter-male courtship. These results have potential implications for thinking about the role of related neuromodulatory systems in mammals.
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Affiliation(s)
- Kiichi Watanabe
- Division of Biology and Biological Engineering 156-29 and the Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, USA; Howard Hughes Medical Institute
| | - Hui Chiu
- Division of Biology and Biological Engineering 156-29 and the Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, USA; Howard Hughes Medical Institute
| | - Barret D Pfeiffer
- Howard Hughes Medical Institute; Janelia Research Campus, HHMI, Ashburn VA, USA
| | - Allan M Wong
- Howard Hughes Medical Institute; Janelia Research Campus, HHMI, Ashburn VA, USA
| | - Eric D Hoopfer
- Division of Biology and Biological Engineering 156-29 and the Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, USA
| | | | - David J Anderson
- Division of Biology and Biological Engineering 156-29 and the Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, USA; Howard Hughes Medical Institute.
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169
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von Reyn CR, Nern A, Williamson WR, Breads P, Wu M, Namiki S, Card GM. Feature Integration Drives Probabilistic Behavior in the Drosophila Escape Response. Neuron 2017. [PMID: 28641115 DOI: 10.1016/j.neuron.2017.05.036] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Animals rely on dedicated sensory circuits to extract and encode environmental features. How individual neurons integrate and translate these features into behavioral responses remains a major question. Here, we identify a visual projection neuron type that conveys predator approach information to the Drosophila giant fiber (GF) escape circuit. Genetic removal of this input during looming stimuli reveals that it encodes angular expansion velocity, whereas other input cell type(s) encode angular size. Motor program selection and timing emerge from linear integration of these two features within the GF. Linear integration improves size detection invariance over prior models and appropriately biases motor selection to rapid, GF-mediated escapes during fast looms. Our findings suggest feature integration, and motor control may occur as simultaneous operations within the same neuron and establish the Drosophila escape circuit as a model system in which these computations may be further dissected at the circuit level. VIDEO ABSTRACT.
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Affiliation(s)
- Catherine R von Reyn
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA; School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA; Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 W. Queen Lane, Philadelphia, PA 19129, USA
| | - Aljoscha Nern
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - W Ryan Williamson
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Patrick Breads
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Ming Wu
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Shigehiro Namiki
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Gwyneth M Card
- Janelia Research Campus, HHMI, 19700 Helix Drive, Ashburn, VA 20147, USA.
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170
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Skeath JB, Wilson BA, Romero SE, Snee MJ, Zhu Y, Lacin H. The extracellular metalloprotease AdamTS-A anchors neural lineages in place within and preserves the architecture of the central nervous system. Development 2017; 144:3102-3113. [PMID: 28760813 DOI: 10.1242/dev.145854] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 07/21/2017] [Indexed: 12/13/2022]
Abstract
The extracellular matrix (ECM) regulates cell migration and sculpts organ shape. AdamTS proteins are extracellular metalloproteases known to modify ECM proteins and promote cell migration, but demonstrated roles for AdamTS proteins in regulating CNS structure and ensuring cell lineages remain fixed in place have not been uncovered. Using forward genetic approaches in Drosophila, we find that reduction of AdamTS-A function induces both the mass exodus of neural lineages out of the CNS and drastic perturbations to CNS structure. Expressed and active in surface glia, AdamTS-A acts in parallel to perlecan and in opposition to viking/collagen IV and βPS-integrin to keep CNS lineages rooted in place and to preserve the structural integrity of the CNS. viking/collagen IV and βPS-integrin are known to promote tissue stiffness and oppose the function of perlecan, which reduces tissue stiffness. Our work supports a model in which AdamTS-A anchors cells in place and preserves CNS architecture by reducing tissue stiffness.
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Affiliation(s)
- James B Skeath
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Beth A Wilson
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Selena E Romero
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Mark J Snee
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Yi Zhu
- Department of Genetics, Washington University School of Medicine, 4523 Clayton Avenue, St Louis, MO 63110, USA
| | - Haluk Lacin
- Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
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171
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Strother JA, Wu ST, Wong AM, Nern A, Rogers EM, Le JQ, Rubin GM, Reiser MB. The Emergence of Directional Selectivity in the Visual Motion Pathway of Drosophila. Neuron 2017; 94:168-182.e10. [PMID: 28384470 DOI: 10.1016/j.neuron.2017.03.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 12/22/2016] [Accepted: 03/08/2017] [Indexed: 01/19/2023]
Abstract
The perception of visual motion is critical for animal navigation, and flies are a prominent model system for exploring this neural computation. In Drosophila, the T4 cells of the medulla are directionally selective and necessary for ON motion behavioral responses. To examine the emergence of directional selectivity, we developed genetic driver lines for the neuron types with the most synapses onto T4 cells. Using calcium imaging, we found that these neuron types are not directionally selective and that selectivity arises in the T4 dendrites. By silencing each input neuron type, we identified which neurons are necessary for T4 directional selectivity and ON motion behavioral responses. We then determined the sign of the connections between these neurons and T4 cells using neuronal photoactivation. Our results indicate a computational architecture for motion detection that is a hybrid of classic theoretical models.
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Affiliation(s)
- James A Strother
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Shiuan-Tze Wu
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Allan M Wong
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Edward M Rogers
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Jasmine Q Le
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Michael B Reiser
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
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172
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An Array of Descending Visual Interneurons Encoding Self-Motion in Drosophila. J Neurosci 2017; 36:11768-11780. [PMID: 27852783 DOI: 10.1523/jneurosci.2277-16.2016] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/22/2016] [Accepted: 09/24/2016] [Indexed: 11/21/2022] Open
Abstract
The means by which brains transform sensory information into coherent motor actions is poorly understood. In flies, a relatively small set of descending interneurons are responsible for conveying sensory information and higher-order commands from the brain to motor circuits in the ventral nerve cord. Here, we describe three pairs of genetically identified descending interneurons that integrate information from wide-field visual interneurons and project directly to motor centers controlling flight behavior. We measured the physiological responses of these three cells during flight and found that they respond maximally to visual movement corresponding to rotation around three distinct body axes. After characterizing the tuning properties of an array of nine putative upstream visual interneurons, we show that simple linear combinations of their outputs can predict the responses of the three descending cells. Last, we developed a machine vision-tracking system that allows us to monitor multiple motor systems simultaneously and found that each visual descending interneuron class is correlated with a discrete set of motor programs. SIGNIFICANCE STATEMENT Most animals possess specialized sensory systems for encoding body rotation, which they use for stabilizing posture and regulating motor actions. In flies and other insects, the visual system contains an array of specialized neurons that integrate local optic flow to estimate body rotation during locomotion. However, the manner in which the output of these cells is transformed by the downstream neurons that innervate motor centers is poorly understood. We have identified a set of three visual descending neurons that integrate the output of nine large-field visual interneurons and project directly to flight motor centers. Our results provide new insight into how the sensory information that encodes body motion is transformed into a code that is appropriate for motor actions.
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173
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Knecht ZA, Silbering AF, Cruz J, Yang L, Croset V, Benton R, Garrity PA. Ionotropic Receptor-dependent moist and dry cells control hygrosensation in Drosophila. eLife 2017. [PMID: 28621663 PMCID: PMC5495567 DOI: 10.7554/elife.26654] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Insects use hygrosensation (humidity sensing) to avoid desiccation and, in vectors such as mosquitoes, to locate vertebrate hosts. Sensory neurons activated by either dry or moist air (‘dry cells’ and ‘moist cells’) have been described in many insects, but their behavioral roles and the molecular basis of their hygrosensitivity remain unclear. We recently reported that Drosophila hygrosensation relies on three Ionotropic Receptors (IRs) required for dry cell function: IR25a, IR93a and IR40a (Knecht et al., 2016). Here, we discover Drosophila moist cells and show that they require IR25a and IR93a together with IR68a, a conserved, but orphan IR. Both IR68a- and IR40a-dependent pathways drive hygrosensory behavior: each is important for dry-seeking by hydrated flies and together they underlie moist-seeking by dehydrated flies. These studies reveal that humidity sensing in Drosophila, and likely other insects, involves the combined activity of two molecularly related but neuronally distinct hygrosensing systems. DOI:http://dx.doi.org/10.7554/eLife.26654.001
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Affiliation(s)
- Zachary A Knecht
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Ana F Silbering
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Joyner Cruz
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Ludi Yang
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Vincent Croset
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Paul A Garrity
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
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174
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Sensory integration and neuromodulatory feedback facilitate Drosophila mechanonociceptive behavior. Nat Neurosci 2017; 20:1085-1095. [PMID: 28604684 PMCID: PMC5931224 DOI: 10.1038/nn.4580] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 05/01/2017] [Indexed: 12/17/2022]
Abstract
Nociception is an evolutionary conserved mechanism to encode and process harmful environmental stimuli. Like most animals, Drosophila larvae respond to a variety of nociceptive stimuli, including noxious touch and temperature, with a stereotyped escape response through activation of multimodal nociceptors. How behavioral responses to these different modalities are processed and integrated by the downstream network remains poorly understood. By combining transsynaptic labeling, ultrastructural analysis, calcium imaging, optogenetic and behavioral analyses, we uncovered a circuit specific for mechano- but not thermo-nociception. Interestingly, integration of mechanosensory input from innocuous and nociceptive sensory neurons is required for robust mechano-nociceptive responses. We further show that neurons integrating mechanosensory input facilitate primary nociceptive output via releasing short Neuropeptide F (sNPF), the Drosophila Neuropeptide Y (NPY) homolog. Our findings unveil how integration of somatosensory input and neuropeptide-mediated modulation can produce robust modality-specific escape behavior.
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175
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Baumann AA, Texada MJ, Chen HM, Etheredge JN, Miller DL, Picard S, Warner R, Truman JW, Riddiford LM. Genetic tools to study juvenile hormone action in Drosophila. Sci Rep 2017; 7:2132. [PMID: 28522854 PMCID: PMC5437021 DOI: 10.1038/s41598-017-02264-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 04/10/2017] [Indexed: 12/04/2022] Open
Abstract
The insect juvenile hormone receptor is a basic helix-loop-helix (bHLH), Per-Arnt-Sim (PAS) domain protein, a novel type of hormone receptor. In higher flies like Drosophila, the ancestral receptor germ cell-expressed (gce) gene has duplicated to yield the paralog Methoprene-tolerant (Met). These paralogous receptors share redundant function during development but play unique roles in adults. Some aspects of JH function apparently require one receptor or the other. To provide a foundation for studying JH receptor function, we have recapitulated endogenous JH receptor expression with single cell resolution. Using Bacteria Artificial Chromosome (BAC) recombineering and a transgenic knock-in, we have generated a spatiotemporal expressional atlas of Met and gce throughout development. We demonstrate JH receptor expression in known JH target tissues, in which temporal expression corresponds with periods of hormone sensitivity. Larval expression largely supports the notion of functional redundancy. Furthermore, we provide the neuroanatomical distribution of JH receptors in both the larval and adult central nervous system, which will serve as a platform for future studies regarding JH action on insect behavior.
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Affiliation(s)
- A A Baumann
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA. .,University of Tennessee, College of Veterinary Medicine, Knoxville, TN, 37996, USA.
| | - M J Texada
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA
| | - H M Chen
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA
| | - J N Etheredge
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA
| | - D L Miller
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA.,National Institute of Neurological Disease and Stroke, NIH, Bethesda, MD, 20892, USA
| | - S Picard
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA
| | - R Warner
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA
| | - J W Truman
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA.,Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, 98250, USA
| | - L M Riddiford
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA, 21047, USA.,Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, 98250, USA
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176
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Veenstra JA, Khammassi H. Rudimentary expression of RYamide in Drosophila melanogaster relative to other Drosophila species points to a functional decline of this neuropeptide gene. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2017; 83:68-79. [PMID: 28286046 DOI: 10.1016/j.ibmb.2017.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/05/2017] [Accepted: 03/05/2017] [Indexed: 06/06/2023]
Abstract
RYamides are arthropod neuropeptides with unknown function. In 2011 two RYamides were isolated from D. melanogaster as the ligands for the G-protein coupled receptor CG5811. The D. melanogaster gene encoding these neuropeptides is highly unusual, as there are four RYamide encoding exons in the current genome assembly, but an exon encoding a signal peptide is absent. Comparing the D. melanogaster gene structure with those from other species, including D. virilis, suggests that the gene is degenerating. RNAseq data from 1634 short sequence read archives at NCBI containing more than 34 billion spots yielded numerous individual spots that correspond to the RYamide encoding exons, of which a large number include the intron-exon boundary at the start of this exon. Although 72 different sequences have been spliced onto this RYamide encoding exon, none codes for the signal peptide of this gene. Thus, the RNAseq data for this gene reveal only noise and no signal. The very small quantities of peptide recovered during isolation and the absence of credible RNAseq data, indicates that the gene is very little expressed, while the RYamide gene structure in D. melanogaster suggests that it might be evolving into a pseudogene. Yet, the identification of the peptides it encodes clearly shows it is still functional. Using region specific antisera, we could localize numerous neurons and enteroendocrine cells in D. willistoni, D. virilis and D. pseudoobscura, but only two adult abdominal neurons in D. melanogaster. Those two neurons project to and innervate the rectal papillae, suggesting that RYamides may be involved in the regulation of water homeostasis.
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Affiliation(s)
- Jan A Veenstra
- INCIA, UMR 5287 CNRS, Université de Bordeaux, Pessac, France.
| | - Hela Khammassi
- INCIA, UMR 5287 CNRS, Université de Bordeaux, Pessac, France
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177
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Facilitating Neuron-Specific Genetic Manipulations in Drosophila melanogaster Using a Split GAL4 Repressor. Genetics 2017; 206:775-784. [PMID: 28363977 PMCID: PMC5499185 DOI: 10.1534/genetics.116.199687] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 03/28/2017] [Indexed: 12/22/2022] Open
Abstract
Efforts to map neural circuits have been galvanized by the development of genetic technologies that permit the manipulation of targeted sets of neurons in the brains of freely behaving animals. The success of these efforts relies on the experimenter’s ability to target arbitrarily small subsets of neurons for manipulation, but such specificity of targeting cannot routinely be achieved using existing methods. In Drosophila melanogaster, a widely-used technique for refined cell type-specific manipulation is the Split GAL4 system, which augments the targeting specificity of the binary GAL4-UAS (Upstream Activating Sequence) system by making GAL4 transcriptional activity contingent upon two enhancers, rather than one. To permit more refined targeting, we introduce here the “Killer Zipper” (KZip+), a suppressor that makes Split GAL4 targeting contingent upon a third enhancer. KZip+ acts by disrupting both the formation and activity of Split GAL4 heterodimers, and we show how this added layer of control can be used to selectively remove unwanted cells from a Split GAL4 expression pattern or to subtract neurons of interest from a pattern to determine their requirement in generating a given phenotype. To facilitate application of the KZip+ technology, we have developed a versatile set of LexAop-KZip+ fly lines that can be used directly with the large number of LexA driver lines with known expression patterns. KZip+ significantly sharpens the precision of neuronal genetic control available in Drosophila and may be extended to other organisms where Split GAL4-like systems are used.
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178
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Klassen MP, Peters CJ, Zhou S, Williams HH, Jan LY, Jan YN. Age-dependent diastolic heart failure in an in vivo Drosophila model. eLife 2017; 6. [PMID: 28328397 PMCID: PMC5362267 DOI: 10.7554/elife.20851] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 02/11/2017] [Indexed: 12/13/2022] Open
Abstract
While the signals and complexes that coordinate the heartbeat are well established, how the heart maintains its electromechanical rhythm over a lifetime remains an open question with significant implications to human health. Reasoning that this homeostatic challenge confronts all pulsatile organs, we developed a high resolution imaging and analysis toolset for measuring cardiac function in intact, unanesthetized Drosophila melanogaster. We demonstrate that, as in humans, normal aging primarily manifests as defects in relaxation (diastole) while preserving contractile performance. Using this approach, we discovered that a pair of two-pore potassium channel (K2P) subunits, largely dispensable early in life, are necessary for terminating contraction (systole) in aged animals, where their loss culminates in fibrillatory cardiac arrest. As the pumping function of its heart is acutely dispensable for survival, Drosophila represents a uniquely accessible model for understanding the signaling networks maintaining cardiac performance during normal aging.
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Affiliation(s)
- Matthew P Klassen
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Christian J Peters
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Shiwei Zhou
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Hannah H Williams
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
| | - Lily Yeh Jan
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Yuh Nung Jan
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States
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179
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Ueoka Y, Hiroi M, Abe T, Tabata T. Suppression of a single pair of mushroom body output neurons in Drosophila triggers aversive associations. FEBS Open Bio 2017; 7:562-576. [PMID: 28396840 PMCID: PMC5377409 DOI: 10.1002/2211-5463.12203] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 11/14/2022] Open
Abstract
Memory includes the processes of acquisition, consolidation and retrieval. In the study of aversive olfactory memory in Drosophila melanogaster, flies are first exposed to an odor (conditioned stimulus, CS+) that is associated with an electric shock (unconditioned stimulus, US), then to another odor (CS−) without the US, before allowing the flies to choose to avoid one of the two odors. The center for memory formation is the mushroom body which consists of Kenyon cells (KCs), dopaminergic neurons (DANs) and mushroom body output neurons (MBONs). However, the roles of individual neurons are not fully understood. We focused on the role of a single pair of GABAergic neurons (MBON‐γ1pedc) and found that it could inhibit the effects of DANs, resulting in the suppression of aversive memory acquisition during the CS− odor presentation, but not during the CS+ odor presentation. We propose that MBON‐γ1pedc suppresses the DAN‐dependent effect that can convey the aversive US during the CS− odor presentation, and thereby prevents an insignificant stimulus from becoming an aversive US.
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Affiliation(s)
- Yutaro Ueoka
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuJapan
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Makoto Hiroi
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Takashi Abe
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Tetsuya Tabata
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuJapan
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
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180
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Second-Generation Drosophila Chemical Tags: Sensitivity, Versatility, and Speed. Genetics 2017; 205:1399-1408. [PMID: 28209589 PMCID: PMC5378102 DOI: 10.1534/genetics.116.199281] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/10/2017] [Indexed: 11/22/2022] Open
Abstract
Thick tissue specimens present major challenges for labeling cells and subcellular structures in a rapid and reliable manner. Sutcliffe et al. present... Labeling and visualizing cells and subcellular structures within thick tissues, whole organs, and even intact animals is key to studying biological processes. This is particularly true for studies of neural circuits where neurons form submicron synapses but have arbors that may span millimeters in length. Traditionally, labeling is achieved by immunofluorescence; however, diffusion of antibody molecules (>100 kDa) is slow and often results in uneven labeling with very poor penetration into the center of thick specimens; these limitations can be partially addressed by extending staining protocols to over a week (Drosophila brain) and months (mice). Recently, we developed an alternative approach using genetically encoded chemical tags CLIP, SNAP, Halo, and TMP for tissue labeling; this resulted in >100-fold increase in labeling speed in both mice and Drosophila, at the expense of a considerable drop in absolute sensitivity when compared to optimized immunofluorescence staining. We now present a second generation of UAS- and LexA-responsive CLIPf, SNAPf, and Halo chemical labeling reagents for flies. These multimerized tags, with translational enhancers, display up to 64-fold increase in sensitivity over first-generation reagents. In addition, we developed a suite of conditional reporters (4xSNAPf tag and CLIPf-SNAPf-Halo2) that are activated by the DNA recombinase Bxb1. Our new reporters can be used with weak and strong GAL4 and LexA drivers and enable stochastic, intersectional, and multicolor Brainbow labeling. These improvements in sensitivity and experimental versatility, while still retaining the substantial speed advantage that is a signature of chemical labeling, should significantly increase the scope of this technology.
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181
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Arthur LL, Chung JJ, Jankirama P, Keefer KM, Kolotilin I, Pavlovic-Djuranovic S, Chalker DL, Grbic V, Green R, Menassa R, True HL, Skeath JB, Djuranovic S. Rapid generation of hypomorphic mutations. Nat Commun 2017; 8:14112. [PMID: 28106166 PMCID: PMC5263891 DOI: 10.1038/ncomms14112] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 11/30/2016] [Indexed: 01/05/2023] Open
Abstract
Hypomorphic mutations are a valuable tool for both genetic analysis of gene function and for synthetic biology applications. However, current methods to generate hypomorphic mutations are limited to a specific organism, change gene expression unpredictably, or depend on changes in spatial-temporal expression of the targeted gene. Here we present a simple and predictable method to generate hypomorphic mutations in model organisms by targeting translation elongation. Adding consecutive adenosine nucleotides, so-called polyA tracks, to the gene coding sequence of interest will decrease translation elongation efficiency, and in all tested cell cultures and model organisms, this decreases mRNA stability and protein expression. We show that protein expression is adjustable independent of promoter strength and can be further modulated by changing sequence features of the polyA tracks. These characteristics make this method highly predictable and tractable for generation of programmable allelic series with a range of expression levels.
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Affiliation(s)
- Laura L. Arthur
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Joyce J. Chung
- Department of Biology, Washington University, St Louis, Missouri 63105, USA
| | - Preetam Jankirama
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A5B7
- Science and Technology Branch, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario, Canada N5V4T3
| | - Kathryn M. Keefer
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Igor Kolotilin
- Scattered Gold Biotechnology Inc. 14 Denali Terrace, London, Ontario, Canada N5X 3W2
| | - Slavica Pavlovic-Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Douglas L. Chalker
- Department of Biology, Washington University, St Louis, Missouri 63105, USA
| | - Vojislava Grbic
- Department of Biology, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A5B7
| | - Rachel Green
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205, USA
| | - Rima Menassa
- Science and Technology Branch, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, Ontario, Canada N5V4T3
| | - Heather L. True
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
- The Hope Center for Neurological Diseases, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - James B. Skeath
- Department of Genetics, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - Sergej Djuranovic
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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182
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Yamagata N, Hiroi M, Kondo S, Abe A, Tanimoto H. Suppression of Dopamine Neurons Mediates Reward. PLoS Biol 2016; 14:e1002586. [PMID: 27997541 PMCID: PMC5172549 DOI: 10.1371/journal.pbio.1002586] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 11/22/2016] [Indexed: 02/05/2023] Open
Abstract
Massive activation of dopamine neurons is critical for natural reward and drug abuse. In contrast, the significance of their spontaneous activity remains elusive. In Drosophila melanogaster, depolarization of the protocerebral anterior medial (PAM) cluster dopamine neurons en masse signals reward to the mushroom body (MB) and drives appetitive memory. Focusing on the functional heterogeneity of PAM cluster neurons, we identified that a single class of PAM neurons, PAM-γ3, mediates sugar reward by suppressing their own activity. PAM-γ3 is selectively required for appetitive olfactory learning, while activation of these neurons in turn induces aversive memory. Ongoing activity of PAM-γ3 gets suppressed upon sugar ingestion. Strikingly, transient inactivation of basal PAM-γ3 activity can substitute for reward and induces appetitive memory. Furthermore, we identified the satiety-signaling neuropeptide Allatostatin A (AstA) as a key mediator that conveys inhibitory input onto PAM-γ3. Our results suggest the significance of basal dopamine release in reward signaling and reveal a circuit mechanism for negative regulation. Dopamine neurons in the midbrain of mammals fire action potentials in response to rewarding stimuli, while punitive stimuli or omission of reward suppress their activity. Different signs in the activity of dopamine neurons thus can encode appetitive and aversive values; however, how these bidirectional activities directly relate to behavior has yet to be elucidated. In fruit flies Drosophila, en masse activation of dopaminergic neurons in the protocerebral anterior medial (PAM) cluster has been shown to signal reward. Here, we demonstrate that a specific sub-class of these dopaminergic neurons, called PAM-γ3, mediates both aversive and appetitive reinforcement through activation and suppression of their activity, respectively. Notably, transient inactivation of the basal activity of PAM-γ3 neurons substitutes for reward and induces appetitive memory formation. Interestingly, we found that Allatostatin A, a neuropeptide that signals satiety, conveys inhibitory input onto PAM-γ3 neurons. Our results highlight the bidirectional activity of defined dopaminergic neurons, which underlies encoding of behaviorally relevant appetitive and aversive values. Transient suppression of a specific subset of dopamine neurons signals reward in the fruit fly Drosophila, suggesting that basal dopamine activity underlies behaviorally relevant valence coding.
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Affiliation(s)
- Nobuhiro Yamagata
- Tohoku University Graduate School of Life Sciences, Sendai, Japan
- * E-mail: (NY); (HT)
| | - Makoto Hiroi
- The University of Tokyo, Institute of Molecular and Cellular Biosciences, Tokyo, Japan
| | - Shu Kondo
- National Institute of Genetics, Mishima, Japan
| | - Ayako Abe
- Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Hiromu Tanimoto
- Tohoku University Graduate School of Life Sciences, Sendai, Japan
- * E-mail: (NY); (HT)
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183
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Nitta Y, Yamazaki D, Sugie A, Hiroi M, Tabata T. DISCO Interacting Protein 2 regulates axonal bifurcation and guidance of Drosophila mushroom body neurons. Dev Biol 2016; 421:233-244. [PMID: 27908785 DOI: 10.1016/j.ydbio.2016.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 11/16/2016] [Accepted: 11/16/2016] [Indexed: 10/20/2022]
Abstract
Axonal branching is one of the key processes within the enormous complexity of the nervous system to enable a single neuron to send information to multiple targets. However, the molecular mechanisms that control branch formation are poorly understood. In particular, previous studies have rarely addressed the mechanisms underlying axonal bifurcation, in which axons form new branches via splitting of the growth cone. We demonstrate that DISCO Interacting Protein 2 (DIP2) is required for precise axonal bifurcation in Drosophila mushroom body (MB) neurons by suppressing ectopic bifurcation and regulating the guidance of sister axons. We also found that DIP2 localize to the plasma membrane. Domain function analysis revealed that the AMP-synthetase domains of DIP2 are essential for its function, which may involve exerting a catalytic activity that modifies fatty acids. Genetic analysis and subsequent biochemical analysis suggested that DIP2 is involved in the fatty acid metabolization of acyl-CoA. Taken together, our results reveal a function of DIP2 in the developing nervous system and provide a potential functional relationship between fatty acid metabolism and axon morphogenesis.
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Affiliation(s)
- Yohei Nitta
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Daisuke Yamazaki
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Atsushi Sugie
- Department of Neuroscience Disease, Center for Transdisciplinary Research, Niigata University, 757, Ichibancho, Asahimachidori, Chuo-ku, Niigata-shi, Niigata 951-8585, Japan
| | - Makoto Hiroi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tetsuya Tabata
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
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184
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Memory Elicited by Courtship Conditioning Requires Mushroom Body Neuronal Subsets Similar to Those Utilized in Appetitive Memory. PLoS One 2016; 11:e0164516. [PMID: 27764141 PMCID: PMC5072562 DOI: 10.1371/journal.pone.0164516] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/25/2016] [Indexed: 11/19/2022] Open
Abstract
An animal’s ability to learn and to form memories is essential for its survival. The fruit fly has proven to be a valuable model system for studies of learning and memory. One learned behavior in fruit flies is courtship conditioning. In Drosophila courtship conditioning, male flies learn not to court females during training with an unreceptive female. He retains a memory of this training and for several hours decreases courtship when subsequently paired with any female. Courtship conditioning is a unique learning paradigm; it uses a positive-valence stimulus, a female fly, to teach a male to decrease an innate behavior, courtship of the female. As such, courtship conditioning is not clearly categorized as either appetitive or aversive conditioning. The mushroom body (MB) region in the fruit fly brain is important for several types of memory; however, the precise subsets of intrinsic and extrinsic MB neurons necessary for courtship conditioning are unknown. Here, we disrupted synaptic signaling by driving a shibirets effector in precise subsets of MB neurons, defined by a collection of split-GAL4 drivers. Out of 75 lines tested, 32 showed defects in courtship conditioning memory. Surprisingly, we did not have any hits in the γ lobe Kenyon cells, a region previously implicated in courtship conditioning memory. We did find that several γ lobe extrinsic neurons were necessary for courtship conditioning memory. Overall, our memory hits in the dopaminergic neurons (DANs) and the mushroom body output neurons were more consistent with results from appetitive memory assays than aversive memory assays. For example, protocerebral anterior medial DANs were necessary for courtship memory, similar to appetitive memory, while protocerebral posterior lateral 1 (PPL1) DANs, important for aversive memory, were not needed. Overall, our results indicate that the MB circuits necessary for courtship conditioning memory coincide with circuits necessary for appetitive memory.
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185
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Competitive Disinhibition Mediates Behavioral Choice and Sequences in Drosophila. Cell 2016; 167:858-870.e19. [PMID: 27720450 DOI: 10.1016/j.cell.2016.09.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/03/2016] [Accepted: 09/06/2016] [Indexed: 01/19/2023]
Abstract
Even a simple sensory stimulus can elicit distinct innate behaviors and sequences. During sensorimotor decisions, competitive interactions among neurons that promote distinct behaviors must ensure the selection and maintenance of one behavior, while suppressing others. The circuit implementation of these competitive interactions is still an open question. By combining comprehensive electron microscopy reconstruction of inhibitory interneuron networks, modeling, electrophysiology, and behavioral studies, we determined the circuit mechanisms that contribute to the Drosophila larval sensorimotor decision to startle, explore, or perform a sequence of the two in response to a mechanosensory stimulus. Together, these studies reveal that, early in sensory processing, (1) reciprocally connected feedforward inhibitory interneurons implement behavioral choice, (2) local feedback disinhibition provides positive feedback that consolidates and maintains the chosen behavior, and (3) lateral disinhibition promotes sequence transitions. The combination of these interconnected circuit motifs can implement both behavior selection and the serial organization of behaviors into a sequence.
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186
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Port F, Bullock SL. Augmenting CRISPR applications in Drosophila with tRNA-flanked sgRNAs. Nat Methods 2016; 13:852-4. [PMID: 27595403 PMCID: PMC5215823 DOI: 10.1038/nmeth.3972] [Citation(s) in RCA: 257] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/02/2016] [Indexed: 12/25/2022]
Abstract
We present tRNA-based vectors for producing multiple clustered regularly interspaced short palindromic repeats (CRISPR) single guide RNAs (sgRNAs) from a single RNA polymerase II or III transcript in Drosophila. The system, which is based on liberation of sgRNAs by processing flanking tRNAs, permits highly efficient multiplexing of Cas9-based mutagenesis. We also demonstrate that the tRNA-sgRNA system markedly increases the efficacy of conditional gene disruption by Cas9 and can promote editing by the recently discovered RNA-guided endonuclease Cpf1.
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Affiliation(s)
- Fillip Port
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Simon L Bullock
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
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187
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Knecht ZA, Silbering AF, Ni L, Klein M, Budelli G, Bell R, Abuin L, Ferrer AJ, Samuel AD, Benton R, Garrity PA. Distinct combinations of variant ionotropic glutamate receptors mediate thermosensation and hygrosensation in Drosophila. eLife 2016; 5. [PMID: 27656904 PMCID: PMC5052030 DOI: 10.7554/elife.17879] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/21/2016] [Indexed: 01/27/2023] Open
Abstract
Ionotropic Receptors (IRs) are a large subfamily of variant ionotropic glutamate receptors present across Protostomia. While these receptors are most extensively studied for their roles in chemosensory detection, recent work has implicated two family members, IR21a and IR25a, in thermosensation in Drosophila. Here we characterize one of the most evolutionarily deeply conserved receptors, IR93a, and show that it is co-expressed and functions with IR21a and IR25a to mediate physiological and behavioral responses to cool temperatures. IR93a is also co-expressed with IR25a and a distinct receptor, IR40a, in a discrete population of sensory neurons in the sacculus, a multi-chambered pocket within the antenna. We demonstrate that this combination of receptors is required for neuronal responses to dry air and behavioral discrimination of humidity differences. Our results identify IR93a as a common component of molecularly and cellularly distinct IR pathways important for thermosensation and hygrosensation in insects. DOI:http://dx.doi.org/10.7554/eLife.17879.001
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Affiliation(s)
- Zachary A Knecht
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, Waltham, United States
| | - Ana F Silbering
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Lina Ni
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, Waltham, United States
| | - Mason Klein
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, United States.,Department of Physics, University of Miami, Coral Gables, United States
| | - Gonzalo Budelli
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, Waltham, United States
| | - Rati Bell
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Liliane Abuin
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Anggie J Ferrer
- Department of Physics, University of Miami, Coral Gables, United States
| | - Aravinthan Dt Samuel
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, United States
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Paul A Garrity
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, Waltham, United States
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188
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Vagnoni A, Bullock SL. A simple method for imaging axonal transport in aging neurons using the adult Drosophila wing. Nat Protoc 2016; 11:1711-23. [PMID: 27560175 DOI: 10.1038/nprot.2016.112] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
There is growing interest in the link between axonal cargo transport and age-associated neuronal dysfunction. The study of axonal transport in neurons of adult animals requires intravital or ex vivo imaging approaches, which are laborious and expensive in vertebrate models. We describe simple, noninvasive procedures for imaging cargo motility within axons using sensory neurons of the translucent Drosophila wing. A key aspect is a method for mounting the intact fly that allows detailed imaging of transport in wing neurons. Coupled with existing genetic tools in Drosophila, this is a tractable system for studying axonal transport over the life span of an animal and thus for characterization of the relationship between cargo dynamics, neuronal aging and disease. Preparation of a sample for imaging takes ∼5 min, with transport typically filmed for 2-3 min per wing. We also document procedures for the quantification of transport parameters from the acquired images and describe how the protocol can be adapted to study other cell biological processes in aging neurons.
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Affiliation(s)
- Alessio Vagnoni
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Simon L Bullock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge, UK
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189
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Jourjine N, Mullaney BC, Mann K, Scott K. Coupled Sensing of Hunger and Thirst Signals Balances Sugar and Water Consumption. Cell 2016; 166:855-866. [PMID: 27477513 PMCID: PMC4983267 DOI: 10.1016/j.cell.2016.06.046] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 05/04/2016] [Accepted: 06/23/2016] [Indexed: 01/08/2023]
Abstract
Hunger and thirst are ancient homeostatic drives for food and water consumption. Although molecular and neural mechanisms underlying these drives are currently being uncovered, less is known about how hunger and thirst interact. Here, we use molecular genetic, behavioral, and anatomical studies in Drosophila to identify four neurons that modulate food and water consumption. Activation of these neurons promotes sugar consumption and restricts water consumption, whereas inactivation promotes water consumption and restricts sugar consumption. By calcium imaging studies, we show that these neurons are directly regulated by a hormone signal of nutrient levels and by osmolality. Finally, we identify a hormone receptor and an osmolality-sensitive ion channel that underlie this regulation. Thus, a small population of neurons senses internal signals of nutrient and water availability to balance sugar and water consumption. Our results suggest an elegant mechanism by which interoceptive neurons oppositely regulate homeostatic drives to eat and drink.
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Affiliation(s)
- Nicholas Jourjine
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Brendan C Mullaney
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kevin Mann
- 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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190
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Repression of Pumilio Protein Expression by Rbfox1 Promotes Germ Cell Differentiation. Dev Cell 2016; 36:562-71. [PMID: 26954550 DOI: 10.1016/j.devcel.2016.02.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 01/11/2016] [Accepted: 02/08/2016] [Indexed: 11/21/2022]
Abstract
RNA-binding Fox (Rbfox) proteins have well-established roles in regulating alternative splicing, but specific Rbfox isoforms lack nuclear localization signals and accumulate in the cytoplasm. The potential splicing-independent functions of these proteins remain unknown. Here we demonstrate that cytoplasmic Drosophila Rbfox1 regulates germ cell development and represses the translation of mRNAs containing (U)GCAUG elements within their 3'UTRs. During germline cyst differentiation, Rbfox1 targets pumilio mRNA for destabilization and translational silencing, thereby promoting germ cell development. Mis-expression of pumilio results in the formation of germline tumors, which contain cysts that break down and dedifferentiate back to single, mitotically active cells. Together, these results reveal that cytoplasmic Rbfox family members regulate the translation of specific target mRNAs. In the Drosophila ovary, this activity provides a genetic barrier that prevents germ cells from reverting back to an earlier developmental state. The finding that Rbfox proteins regulate mRNA translation has implications for Rbfox-related diseases.
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191
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Yang B, Liu J, Jiang Y, Chen F. Chlorella species as hosts for genetic engineering and expression of heterologous proteins: Progress, challenge and perspective. Biotechnol J 2016; 11:1244-1261. [PMID: 27465356 DOI: 10.1002/biot.201500617] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 11/08/2022]
Abstract
The species of Chlorella represent a highly specialized group of green microalgae that can produce high levels of protein. Many Chlorella strains can grow rapidly and achieve high cell density under controlled conditions and are thus considered to be promising protein sources. Many advances in the genetic engineering of Chlorella have occurred in recent years, with significant developments in successful expression of heterologous proteins for various applications. Nevertheless, a lot of obstacles remain to be addressed, and a sophisticated and stable Chlorella expression system has yet to emerge. This review provides a brief summary of current knowledge on Chlorella and an overview of recent progress in the genetic engineering of Chlorella, and highlights the advances in the development of a genetic toolbox of Chlorella for heterologous protein expression. Research directions to further exploit the Chlorella expression system with respect to both challenges and perspectives are also discussed. This paper serves as a comprehensive literature review for the Chlorella community and will provide valuable insights into future exploration of Chlorella as a promising host for heterologous protein expression.
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Affiliation(s)
- Bo Yang
- Institute for Food and Bioresource Engineering, College of Engineering, Peking University, Beijing, China.,School of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China
| | - Jin Liu
- Institute for Food and Bioresource Engineering, College of Engineering, Peking University, Beijing, China. .,Singapore-Peking University Research Centre for a Sustainable Low-Carbon Future, CREATE Tower, Singapore.
| | - Yue Jiang
- Runke Bioengineering Co., Ltd., Zhangzhou, China.
| | - Feng Chen
- Institute for Food and Bioresource Engineering, College of Engineering, Peking University, Beijing, China.,Singapore-Peking University Research Centre for a Sustainable Low-Carbon Future, CREATE Tower, Singapore
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192
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Mellert DJ, Williamson WR, Shirangi TR, Card GM, Truman JW. Genetic and Environmental Control of Neurodevelopmental Robustness in Drosophila. PLoS One 2016; 11:e0155957. [PMID: 27223118 PMCID: PMC4880190 DOI: 10.1371/journal.pone.0155957] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/06/2016] [Indexed: 11/19/2022] Open
Abstract
Interindividual differences in neuronal wiring may contribute to behavioral individuality and affect susceptibility to neurological disorders. To investigate the causes and potential consequences of wiring variation in Drosophila melanogaster, we focused on a hemilineage of ventral nerve cord interneurons that exhibits morphological variability. We find that late-born subclasses of the 12A hemilineage are highly sensitive to genetic and environmental variation. Neurons in the second thoracic segment are particularly variable with regard to two developmental decisions, whereas its segmental homologs are more robust. This variability “hotspot” depends on Ultrabithorax expression in the 12A neurons, indicating variability is cell-intrinsic and under genetic control. 12A development is more variable and sensitive to temperature in long-established laboratory strains than in strains recently derived from the wild. Strains with a high frequency of one of the 12A variants also showed a high frequency of animals with delayed spontaneous flight initiation, whereas other wing-related behaviors did not show such a correlation and were thus not overtly affected by 12A variation. These results show that neurodevelopmental robustness is variable and under genetic control in Drosophila and suggest that the fly may serve as a model for identifying conserved gene pathways that stabilize wiring in stressful developmental environments. Moreover, some neuronal lineages are variation hotspots and thus may be more amenable to evolutionary change.
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Affiliation(s)
- David J. Mellert
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
- * E-mail:
| | - W. Ryan Williamson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Troy R. Shirangi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Gwyneth M. Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - James W. Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
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193
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Ni L, Klein M, Svec KV, Budelli G, Chang EC, Ferrer AJ, Benton R, Samuel AD, Garrity PA. The Ionotropic Receptors IR21a and IR25a mediate cool sensing in Drosophila. eLife 2016; 5. [PMID: 27126188 PMCID: PMC4851551 DOI: 10.7554/elife.13254] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 03/18/2016] [Indexed: 01/25/2023] Open
Abstract
Animals rely on highly sensitive thermoreceptors to seek out optimal temperatures, but the molecular mechanisms of thermosensing are not well understood. The Dorsal Organ Cool Cells (DOCCs) of the Drosophila larva are a set of exceptionally thermosensitive neurons critical for larval cool avoidance. Here, we show that DOCC cool-sensing is mediated by Ionotropic Receptors (IRs), a family of sensory receptors widely studied in invertebrate chemical sensing. We find that two IRs, IR21a and IR25a, are required to mediate DOCC responses to cooling and are required for cool avoidance behavior. Furthermore, we find that ectopic expression of IR21a can confer cool-responsiveness in an Ir25a-dependent manner, suggesting an instructive role for IR21a in thermosensing. Together, these data show that IR family receptors can function together to mediate thermosensation of exquisite sensitivity. DOI:http://dx.doi.org/10.7554/eLife.13254.001 Animals need to be able to sense temperatures for a number of reasons. For example, this ability allows animals to avoid conditions that are either too hot or too cold, and to maintain an optimal body temperature. Most animals detect temperature via nerve cells called thermoreceptors. These sensors are often extremely sensitive and some can even detect changes in temperature of just a few thousandths of a degree per second. However, it is not clear how thermoreceptors detect temperature with such sensitivity, and many of the key molecules involved in this ability are unknown. In 2015, researchers discovered a class of highly sensitive nerve cells that allow fruit fly larvae to navigate away from unfavorably cool temperatures. Now, Ni, Klein et al. – who include some of the researchers involved in the 2015 work – have determined that these nerves use a combination of two receptors to detect cooling. Unexpectedly, these two receptors – Ionotropic Receptors called IR21a and IR25a – had previously been implicated in the detection of chemicals rather than temperature. IR25a was well-known to combine with other related receptors to detect an array of tastes and smells, while IR21a was thought to act in a similar way but had not been associated with detecting any specific chemicals. These findings demonstrate that the combination of IR21a and IR25a detects temperature instead. Together, these findings reveal a new molecular mechanism that underlies an animal’s ability to sense temperature. These findings also raise the possibility that other “orphan” Ionotropic Receptors, which have not been shown to detect any specific chemicals, might actually contribute to sensing temperature instead. Further work will explore this possibility and attempt to uncover precisely how IR21a and IR25a work to detect cool temperatures. DOI:http://dx.doi.org/10.7554/eLife.13254.002
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Affiliation(s)
- Lina Ni
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Mason Klein
- Department of Physics, Harvard University, Cambridge, United States.,Department of Physics, University of Miami, Coral Gables, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Kathryn V Svec
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Gonzalo Budelli
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Elaine C Chang
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
| | - Anggie J Ferrer
- Department of Physics, University of Miami, Coral Gables, United States
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Aravinthan Dt Samuel
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Paul A Garrity
- National Center for Behavioral Genomics, Brandeis University, Waltham, United States.,Volen Center for Complex Systems, Brandeis University, Waltham, United States.,Department of Biology, Brandeis University, Waltham, United States
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194
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Vogt K, Aso Y, Hige T, Knapek S, Ichinose T, Friedrich AB, Turner GC, Rubin GM, Tanimoto H. Direct neural pathways convey distinct visual information to Drosophila mushroom bodies. eLife 2016; 5. [PMID: 27083044 PMCID: PMC4884080 DOI: 10.7554/elife.14009] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 04/14/2016] [Indexed: 01/02/2023] Open
Abstract
Previously, we demonstrated that visual and olfactory associative memories of Drosophila share mushroom body (MB) circuits (Vogt et al., 2014). Unlike for odor representation, the MB circuit for visual information has not been characterized. Here, we show that a small subset of MB Kenyon cells (KCs) selectively responds to visual but not olfactory stimulation. The dendrites of these atypical KCs form a ventral accessory calyx (vAC), distinct from the main calyx that receives olfactory input. We identified two types of visual projection neurons (VPNs) directly connecting the optic lobes and the vAC. Strikingly, these VPNs are differentially required for visual memories of color and brightness. The segregation of visual and olfactory domains in the MB allows independent processing of distinct sensory memories and may be a conserved form of sensory representations among insects. DOI:http://dx.doi.org/10.7554/eLife.14009.001
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Affiliation(s)
- Katrin Vogt
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Toshihide Hige
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Stephan Knapek
- Max-Planck Institut für Neurobiologie, Martinsried, Germany
| | - Toshiharu Ichinose
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | | | - Glenn C Turner
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Hiromu Tanimoto
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
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195
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Serbe E, Meier M, Leonhardt A, Borst A. Comprehensive Characterization of the Major Presynaptic Elements to the Drosophila OFF Motion Detector. Neuron 2016; 89:829-41. [PMID: 26853306 DOI: 10.1016/j.neuron.2016.01.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/18/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
Abstract
Estimating motion is a fundamental task for the visual system of sighted animals. In Drosophila, direction-selective T4 and T5 cells respond to moving brightness increments (ON) and decrements (OFF), respectively. Current algorithmic models of the circuit are based on the interaction of two differentially filtered signals. However, electron microscopy studies have shown that T5 cells receive their major input from four classes of neurons: Tm1, Tm2, Tm4, and Tm9. Using two-photon calcium imaging, we demonstrate that T5 is the first direction-selective stage within the OFF pathway. The four cells provide an array of spatiotemporal filters to T5. Silencing their synaptic output in various combinations, we find that all input elements are involved in OFF motion detection to varying degrees. Our comprehensive survey challenges the simplified view of how neural systems compute the direction of motion and suggests that an intricate interplay of many signals results in direction selectivity.
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Affiliation(s)
- Etienne Serbe
- Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Matthias Meier
- Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany.
| | - Aljoscha Leonhardt
- Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Alexander Borst
- Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
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196
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Cavanaugh DJ, Vigderman AS, Dean T, Garbe DS, Sehgal A. The Drosophila Circadian Clock Gates Sleep through Time-of-Day Dependent Modulation of Sleep-Promoting Neurons. Sleep 2016; 39:345-56. [PMID: 26350473 DOI: 10.5665/sleep.5442] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 08/12/2015] [Indexed: 01/20/2023] Open
Abstract
STUDY OBJECTIVES Sleep is under the control of homeostatic and circadian processes, which interact to determine sleep timing and duration, but the mechanisms through which the circadian system modulates sleep are largely unknown. We therefore used adult-specific, temporally controlled neuronal activation and inhibition to identify an interaction between the circadian clock and a novel population of sleep-promoting neurons in Drosophila. METHODS Transgenic flies expressed either dTRPA1, a neuronal activator, or Shibire(ts1), an inhibitor of synaptic release, in small subsets of neurons. Sleep, as determined by activity monitoring and video tracking, was assessed before and after temperature-induced activation or inhibition using these effector molecules. We compared the effect of these manipulations in control flies and in mutant flies that lacked components of the molecular circadian clock. RESULTS Adult-specific activation or inhibition of a population of neurons that projects to the sleep-promoting dorsal Fan-Shaped Body resulted in bidirectional control over sleep. Interestingly, the magnitude of the sleep changes were time-of-day dependent. Activation of sleep-promoting neurons was maximally effective during the middle of the day and night, and was relatively ineffective during the day-to-night and night-to-day transitions. These time-ofday specific effects were absent in flies that lacked functional circadian clocks. CONCLUSIONS We conclude that the circadian system functions to gate sleep through active inhibition at specific times of day. These data identify a mechanism through which the circadian system prevents premature sleep onset in the late evening, when homeostatic sleep drive is high.
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Affiliation(s)
- Daniel J Cavanaugh
- Penn Chronobiology Program, Philadelphia PA.,Current Address: Department of Biology, Loyola University Chicago, Chicago IL
| | | | - Terry Dean
- Penn Chronobiology Program, Philadelphia PA
| | | | - Amita Sehgal
- Penn Chronobiology Program, Philadelphia PA.,Howard Hughes Medical Institute, University of Pennsylvania, Philadelphia PA
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197
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Zhang KX, Tan L, Pellegrini M, Zipursky SL, McEwen JM. Rapid Changes in the Translatome during the Conversion of Growth Cones to Synaptic Terminals. Cell Rep 2016; 14:1258-1271. [PMID: 26832407 DOI: 10.1016/j.celrep.2015.12.102] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 12/04/2015] [Accepted: 12/21/2015] [Indexed: 12/01/2022] Open
Abstract
A common step in the formation of neural circuits is the conversion of growth cones to presynaptic terminals. Characterizing patterns of global gene expression during this process is problematic due to the cellular diversity of the brain and the complex temporal dynamics of development. Here, we take advantage of the synchronous conversion of Drosophila photoreceptor growth cones into presynaptic terminals to explore global changes in gene expression during presynaptic differentiation. Using a tandemly tagged ribosome trap (T-TRAP) and RNA sequencing (RNA-seq) at multiple developmental times, we observed dramatic changes in coding and non-coding RNAs with presynaptic differentiation. Marked changes in the mRNA encoding transmembrane and secreted proteins occurred preferentially. The 3' UTRs of transcripts encoding synaptic proteins were preferentially lengthened, and these extended UTRs were preferentially enriched for sites recognized by RNA binding proteins. These data provide a rich resource for uncovering the regulatory logic underlying presynaptic differentiation.
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Affiliation(s)
- Kelvin Xi Zhang
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA 90095, USA
| | - Liming Tan
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA 90095, USA
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, P.O. Box 951606, Los Angeles, CA 90095, USA
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA 90095, USA.
| | - Jason M McEwen
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles CA 90095, USA
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198
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Identified Serotonin-Releasing Neurons Induce Behavioral Quiescence and Suppress Mating in Drosophila. J Neurosci 2016; 35:12792-812. [PMID: 26377467 DOI: 10.1523/jneurosci.1638-15.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Animals show different levels of activity that are reflected in sensory responsiveness and endogenously generated behaviors. Biogenic amines have been determined to be causal factors for these states of arousal. It is well established that, in Drosophila, dopamine and octopamine promote increased arousal. However, little is known about factors that regulate arousal negatively and induce states of quiescence. Moreover, it remains unclear whether global, diffuse modulatory systems comprehensively affecting brain activity determine general states of arousal. Alternatively, individual aminergic neurons might selectively modulate the animals' activity in a distinct behavioral context. Here, we show that artificially activating large populations of serotonin-releasing neurons induces behavioral quiescence and inhibits feeding and mating. We systematically narrowed down a role of serotonin in inhibiting endogenously generated locomotor activity to neurons located in the posterior medial protocerebrum. We identified neurons of this cell cluster that suppress mating, but not feeding behavior. These results suggest that serotonin does not uniformly act as global, negative modulator of general arousal. Rather, distinct serotoninergic neurons can act as inhibitory modulators of specific behaviors. SIGNIFICANCE STATEMENT An animal's responsiveness to external stimuli and its various types of endogenously generated, motivated behavior are highly dynamic and change between states of high activity and states of low activity. It remains unclear whether these states are mediated by unitary modulatory systems globally affecting brain activity, or whether distinct neurons modulate specific neuronal circuits underlying particular types of behavior. Using the model organism Drosophila melanogaster, we find that activating large proportions of serotonin-releasing neurons induces behavioral quiescence. Moreover, distinct serotonin-releasing neurons that we genetically isolated and identified negatively affect aspects of mating behavior, but not food uptake. This demonstrates that individual serotoninergic neurons can modulate distinct types of behavior selectively.
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199
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Abstract
Binary expression systems are flexible and versatile genetic tools in Drosophila. The Q-system is a recently developed repressible binary expression system that offers new possibilities for transgene expression and genetic manipulations. In this review chapter, we focus on current state-of-the-art Q-system tools and reagents. We also discuss in vivo applications of the Q-system, together with GAL4/UAS and LexA/LexAop systems, for simultaneous expression of multiple effectors, intersectional labeling, and clonal analysis.
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200
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ICHINOSE T, TANIMOTO H. Dynamics of memory-guided choice behavior in Drosophila. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2016; 92:346-357. [PMID: 27725473 PMCID: PMC5243950 DOI: 10.2183/pjab.92.346] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 07/25/2016] [Indexed: 06/06/2023]
Abstract
Memory retrieval requires both accuracy and speed. Olfactory learning of the fruit fly Drosophila melanogaster serves as a powerful model system to identify molecular and neuronal substrates of memory and memory-guided behavior. The behavioral expression of olfactory memory has traditionally been tested as a conditioned odor response in a simple T-maze, which measures the result, but not the speed, of odor choice. Here, we developed multiplexed T-mazes that allow video recording of the choice behavior. Automatic fly counting in each arm of the maze visualizes choice dynamics. Using this setup, we show that the transient blockade of serotonergic neurons slows down the choice, while leaving the eventual choice intact. In contrast, activation of the same neurons impairs the eventual performance leaving the choice speed unchanged. Our new apparatus contributes to elucidating how the speed and the accuracy of memory retrieval are implemented in the fly brain.
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Affiliation(s)
- Toshiharu ICHINOSE
- Tohoku University Graduate School of Life Sciences, Sendai, Japan
- Max-Planck Institut für Neurobiologie, Martinsried, Germany
| | - Hiromu TANIMOTO
- Tohoku University Graduate School of Life Sciences, Sendai, Japan
- Max-Planck Institut für Neurobiologie, Martinsried, Germany
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