1
|
Harris CM, Dinges GF, Haberkorn A, Gebehart C, Büschges A, Zill SN. Gradients in mechanotransduction of force and body weight in insects. ARTHROPOD STRUCTURE & DEVELOPMENT 2020; 58:100970. [PMID: 32702647 DOI: 10.1016/j.asd.2020.100970] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Posture and walking require support of the body weight, which is thought to be detected by sensory receptors in the legs. Specificity in sensory encoding occurs through the numerical distribution, size and response range of sense organs. We have studied campaniform sensilla, receptors that detect forces as strains in the insect exoskeleton. The sites of mechanotransduction (cuticular caps) were imaged by light and confocal microscopy in four species (stick insects, cockroaches, blow flies and Drosophila). The numbers of receptors and cap diameters were determined in projection images. Similar groups of receptors are present in the legs of each species (flies lack Group 2 on the anterior trochanter). The number of receptors is generally related to the body weight but similar numbers are found in blow flies and Drosophila, despite a 30 fold difference in their weight. Imaging data indicate that the gradient (range) of cap sizes may more closely correlate with the body weight: the range of cap sizes is larger in blow flies than in Drosophila but similar to that found in juvenile cockroaches. These studies support the idea that morphological properties of force-detecting sensory receptors in the legs may be tuned to reflect the body weight.
Collapse
Affiliation(s)
- Christian M Harris
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25704, USA
| | - Gesa F Dinges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Anna Haberkorn
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Corinna Gebehart
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Ansgar Büschges
- Department of Animal Physiology, Institute of Zoology, Biocenter Cologne, University of Cologne, 50923 Cologne, Germany
| | - Sasha N Zill
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25704, USA.
| |
Collapse
|
2
|
Abstract
The ability of animals to flexibly navigate through complex environments depends on the integration of sensory information with motor commands. The sensory modality most tightly linked to motor control is mechanosensation. Adaptive motor control depends critically on an animal's ability to respond to mechanical forces generated both within and outside the body. The compact neural circuits of insects provide appealing systems to investigate how mechanical cues guide locomotion in rugged environments. Here, we review our current understanding of mechanosensation in insects and its role in adaptive motor control. We first examine the detection and encoding of mechanical forces by primary mechanoreceptor neurons. We then discuss how central circuits integrate and transform mechanosensory information to guide locomotion. Because most studies in this field have been performed in locusts, cockroaches, crickets, and stick insects, the examples we cite here are drawn mainly from these 'big insects'. However, we also pay particular attention to the tiny fruit fly, Drosophila, where new tools are creating new opportunities, particularly for understanding central circuits. Our aim is to show how studies of big insects have yielded fundamental insights relevant to mechanosensation in all animals, and also to point out how the Drosophila toolkit can contribute to future progress in understanding mechanosensory processing.
Collapse
Affiliation(s)
- John C Tuthill
- Department of Physiology and Biophysics, University of Washington, 1705 NE Pacific Street, Seattle, WA 98195, USA.
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
| |
Collapse
|
3
|
Barish S, Volkan PC. Mechanisms of olfactory receptor neuron specification in Drosophila. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:609-21. [PMID: 26088441 PMCID: PMC4744966 DOI: 10.1002/wdev.197] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 05/04/2015] [Accepted: 05/16/2015] [Indexed: 11/05/2022]
Abstract
Detection of a broad range of chemosensory signals is necessary for the survival of multicellular organisms. Chemical signals are the main facilitators of foraging, escape, and social behaviors. To increase detection coverage, animal sensory systems have evolved to create a large number of neurons with highly specific functions. The olfactory system, much like the nervous system as a whole, is astonishingly diverse. The mouse olfactory system has millions of neurons with over a thousand classes, whereas the more compact Drosophila genome has approximately 80 odorant receptor genes that give rise to 50 neuronal classes and 1300 neurons in the adult.(4) Understanding how neuronal diversity is generated remains one of the central questions in developmental neurobiology. Here, we review the current knowledge on the development of the adult Drosophila olfactory system and the progress that has been made toward answering this central question.
Collapse
Affiliation(s)
- Scott Barish
- Department of Biology, Duke University, Durham, NC, USA
| | - Pelin Cayirlioglu Volkan
- Department of Biology, Duke University, Durham, NC, USA.,Duke Institute of Brain Sciences, Duke University, Durham, NC, USA
| |
Collapse
|
4
|
Shahab J, Baratta C, Scuric B, Godt D, Venken KJT, Ringuette MJ. Loss of SPARC dysregulates basal lamina assembly to disrupt larval fat body homeostasis in Drosophila melanogaster. Dev Dyn 2015; 244:540-52. [PMID: 25529377 DOI: 10.1002/dvdy.24243] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND SPARC is a collagen-binding glycoprotein whose functions during early development are unknown. We previously reported that SPARC is expressed in Drosophila by hemocytes and the fat body (FB) and enriched in basal laminae (BL) surrounding tissues, including adipocytes. We sought to explore if SPARC is required for proper BL assembly in the FB. RESULTS SPARC deficiency leads to larval lethality, associated with remodeling of the FB. In the absence of SPARC, FB polygonal adipocytes assume a spherical morphology. Loss-of-function clonal analyses revealed a cell-autonomous accumulation of BL components around mutant cells that include collagen IV (Col lV), Laminin, and Perlecan. Ultrastructural analyses indicate SPARC-deficient adipocytes are surrounded by an aberrant accumulation of a fibrous extracellular matrix. CONCLUSIONS Our data indicate a critical requirement for SPARC for the proper BL assembly in Drosophila FB. Since Col IV within the BL is a prime determinant of cell shape, the rounded appearance of SPARC-deficient adipocytes is due to aberrant assembly of Col IV.
Collapse
Affiliation(s)
- Jaffer Shahab
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
5
|
Engrailed alters the specificity of synaptic connections of Drosophila auditory neurons with the giant fiber. J Neurosci 2014; 34:11691-704. [PMID: 25164665 DOI: 10.1523/jneurosci.1939-14.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We show that a subset of sound-detecting Johnston's Organ neurons (JONs) in Drosophila melanogaster, which express the transcription factors Engrailed (En) and Invected (Inv), form mixed electrical and chemical synaptic inputs onto the giant fiber (GF) dendrite. These synaptic connections are detected by trans-synaptic Neurobiotin (NB) transfer and by colocalization of Bruchpilot-short puncta. We then show that misexpressing En postmitotically in a second subset of sound-responsive JONs causes them to form ectopic electrical and chemical synapses with the GF, in turn causing that postsynaptic neuron to redistribute its dendritic branches into the vicinity of these afferents. We also introduce a simple electrophysiological recording paradigm for quantifying the presynaptic and postsynaptic electrical activity at this synapse, by measuring the extracellular sound-evoked potentials (SEPs) from the antennal nerve while monitoring the likelihood of the GF firing an action potential in response to simultaneous subthreshold sound and voltage stimuli. Ectopic presynaptic expression of En strengthens the synaptic connection, consistent with there being more synaptic contacts formed. Finally, RNAi-mediated knockdown of En and Inv in postmitotic neurons reduces SEP amplitude but also reduces synaptic strength at the JON-GF synapse. Overall, these results suggest that En and Inv in JONs regulate both neuronal excitability and synaptic connectivity.
Collapse
|
6
|
Kuzhandaivel A, Schultz SW, Alkhori L, Alenius M. Cilia-mediated hedgehog signaling in Drosophila. Cell Rep 2014; 7:672-80. [PMID: 24768000 DOI: 10.1016/j.celrep.2014.03.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Revised: 12/20/2013] [Accepted: 03/20/2014] [Indexed: 12/20/2022] Open
Abstract
Cilia mediate Hedgehog (Hh) signaling in vertebrates and Hh deregulation results in several clinical manifestations, such as obesity, cognitive disabilities, developmental malformations, and various cancers. Drosophila cells are nonciliated during development, which has led to the assumption that cilia-mediated Hh signaling is restricted to vertebrates. Here, we identify and characterize a cilia-mediated Hh pathway in Drosophila olfactory sensory neurons. We demonstrate that several fundamental key aspects of the vertebrate cilia pathway, such as ciliary localization of Smoothened and the requirement of the intraflagellar transport system, are present in Drosophila. We show that Cos2 and Fused are required for the ciliary transport of Smoothened and that cilia mediate the expression of the Hh pathway target genes. Taken together, our data demonstrate that Hh signaling in Drosophila can be mediated by two pathways and that the ciliary Hh pathway is conserved from Drosophila to vertebrates.
Collapse
Affiliation(s)
- Anujaianthi Kuzhandaivel
- Department of Clinical and Experimental Medicine, Linkoping University, SE-581 85 Linköping, Sweden
| | - Sebastian W Schultz
- Department of Clinical and Experimental Medicine, Linkoping University, SE-581 85 Linköping, Sweden
| | - Liza Alkhori
- Department of Clinical and Experimental Medicine, Linkoping University, SE-581 85 Linköping, Sweden
| | - Mattias Alenius
- Department of Clinical and Experimental Medicine, Linkoping University, SE-581 85 Linköping, Sweden.
| |
Collapse
|
7
|
Pézier A, Blagburn JM. Auditory responses of engrailed and invected-expressing Johnston's Organ neurons in Drosophila melanogaster. PLoS One 2013; 8:e71419. [PMID: 23940751 PMCID: PMC3734059 DOI: 10.1371/journal.pone.0071419] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 07/03/2013] [Indexed: 11/23/2022] Open
Abstract
The roles of the transcription factor Engrailed (En), and its paralogue Invected (Inv), in adult Drosophila Johnston’s Organ sensory neurons are unknown. We used en-GAL4 driven CD8-GFP and antibody staining to characterize these neurons in the pedicel (second antennal segment). The majority of En and Inv-expressing Johnston’s Organ neurons (En-JONs) are located in the ventral part of the posterior group of JONs, with only a few in the medial group. Anatomical classification of En-JON axon projections shows they are mainly type A and E, with a few type B. Extracellular recording of sound-evoked potentials (SEPs) from the antennal nerve was used along with Kir2.1 silencing to assess the contribution that En-JONs make to the auditory response to pure-tone sound stimuli. Silencing En-JONs reduces the SEP amplitude at the onset of the stimulus by about half at 100, 200 and 400 Hz, and also reduces the steady-state response to 200 Hz. En-JONs respond to 82 dB and 92 dB sounds but not 98 dB. Despite their asymmetrical distribution in the Johnston’s Organ they respond equally strongly to both directions of movement of the arista. This implies that individual neurons are excited in both directions, a conclusion supported by reanalysis of the morphology of the pedicel-funicular joint. Other methods of silencing the JONs were also used: RNAi against the voltage-gated Na+ channel encoded by the para gene, expression of attenuated diphtheria toxin, and expression of a modified influenza toxin M2(H37A). Only the latter was found to be more effective than Kir2.1. Three additional JON subsets were characterized using Flylight GAL4 lines. inv-GAL4 88B12 and Gycβ100B-GAL4 12G03 express in different subsets of A group neurons and CG12484-GAL4 91G04 is expressed in B neurons. All three contribute to the auditory response to 200 Hz tones.
Collapse
Affiliation(s)
- Adeline Pézier
- Institute of Neurobiology, University of Puerto Rico, San Juan, Puerto Rico, United States of America
| | - Jonathan M. Blagburn
- Institute of Neurobiology, University of Puerto Rico, San Juan, Puerto Rico, United States of America
- * E-mail:
| |
Collapse
|
8
|
Latham KL, Liu YS, Taylor BJ. A small cohort of FRU(M) and Engrailed-expressing neurons mediate successful copulation in Drosophila melanogaster. BMC Neurosci 2013; 14:57. [PMID: 23688386 PMCID: PMC3664081 DOI: 10.1186/1471-2202-14-57] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/14/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Drosophila, male flies require the expression of the male-specific Fruitless protein (FRU(M)) within the developing pupal and adult nervous system in order to produce male courtship and copulation behaviors. Recent evidence has shown that specific subsets of FRU(M) neurons are necessary for particular steps of courtship and copulation. In these neurons, FRU(M) function has been shown to be important for determining sex-specific neuronal characteristics, such as neurotransmitter profile and morphology. RESULTS We identified a small cohort of FRU(M) interneurons in the brain and ventral nerve cord by their co-expression with the transcription factor Engrailed (En). We used an En-GAL4 driver to express a fru(M) RNAi construct in order to selectively deplete FRU(M) in these En/FRU(M) co-expressing neurons. In courtship and copulation tests, these males performed male courtship at wild-type levels but were frequently sterile. Sterility was a behavioral phenotype as these En-fru(M)RNAi males were less able to convert a copulation attempt into a stable copulation, or did not maintain copulation for long enough to transfer sperm and/or seminal fluid. CONCLUSIONS We have identified a population of interneurons necessary for successful copulation in Drosophila. These data confirm a model in which subsets of FRU(M) neurons participate in independent neuronal circuits necessary for individual steps of male behavior. In addition, we have determined that these neurons in wild-type males have homologues in females and fru mutants, with similar placement, projection patterns, and neurochemical profiles.
Collapse
Affiliation(s)
- Kristin L Latham
- Department of Zoology, Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331-2914, USA.
| | | | | |
Collapse
|
9
|
Song E, de Bivort B, Dan C, Kunes S. Determinants of the Drosophila odorant receptor pattern. Dev Cell 2012; 22:363-76. [PMID: 22340498 DOI: 10.1016/j.devcel.2011.12.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 10/24/2011] [Accepted: 12/20/2011] [Indexed: 02/04/2023]
Abstract
In most olfactory systems studied to date, neurons that express the same odorant receptor (Or) gene are scattered across sensory epithelia, intermingled with neurons that express different Or genes. In Drosophila, olfactory sensilla that express the same Or gene are dispersed on the antenna and the maxillary palp. Here we show that Or identity is specified in a spatially stereotyped pattern by the cell-autonomous activity of the transcriptional regulators Engrailed and Dachshund. Olfactory sensilla then become highly motile and disperse beneath the epidermis. Thus, positional information and cell motility underlie the dispersed patterns of Drosophila Or gene expression.
Collapse
Affiliation(s)
- Erin Song
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | | |
Collapse
|
10
|
Abstract
The distributed, apparently random pattern of odorant receptor expression is thought to reflect a stochastic choice process. In this issue of Developmental Cell, Song et al. (2012) suggest that the Drosophila pattern is established secondarily from regionally specified cell populations through changes in transcription factor expression and cell migration.
Collapse
Affiliation(s)
- Xalid Bayramli
- Department of Molecular Biology and Genetics, Bogazici University, 34342 Istanbul, Turkey
| | | |
Collapse
|
11
|
Tadesse T, Schmidt M, Walthall WW, Tai PC, Derby CD. Distribution and function of splash, an achaete-scute homolog in the adult olfactory organ of the Caribbean spiny lobster Panulirus argus. Dev Neurobiol 2012; 71:316-35. [PMID: 21394934 DOI: 10.1002/dneu.20862] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
achaete-scute complex (ASC) genes, which encode basic helix-loop-helix transcription factors, regulate embryonic and adult neurogenesis in many animals. In adult arthropods, including crustaceans, ASC homologs have been identified but rarely functionally characterized. We took advantage of the recently identified crustacean homolog, splash (spiny lobster achaete scute homolog), in the olfactory organ of the Caribbean spiny lobster Panulirus argus to examine its role in adult neurogenesis. We tested the hypothesis that splash is associated with but not restricted to sensory neuron formation in the olfactory organ, the antennular lateral flagellum (LF), of adult spiny lobsters. We demonstrated splash labeling in epithelial cells across LF developmental zones (i.e., proliferation and mature zones), in auxiliary cells surrounding dendrites of olfactory receptor neurons (ORNs), and in immature and mature ORNs, but not in granulocytes or chromatophores. Since ORN proliferation varies with molt stage, we examined splash expression across molt stages and found that molt stage affected splash expression in the ORN mature zone but not in the proliferation zone. In vivo incorporation of bromodeoxyuridine (BrdU) showed no correlation in the cellular pattern of splash expression and BrdU labeling. The intensity of splash labeling was dramatically enhanced in the proliferation zones following LF damage, suggesting enhanced splash expression during repair and/or regeneration. We conclude that splash is not closely associated with the formation of sensory neurons under normal physiological conditions, and we propose that splash is involved in repair and regeneration. We also propose that splash has additional roles other than neurogenesis in adult crustaceans.
Collapse
Affiliation(s)
- Tizeta Tadesse
- Neuroscience Institute and Department of Biology, Georgia State University, Atlanta, Georgia, USA.
| | | | | | | | | |
Collapse
|
12
|
Shimono K, Fujimoto A, Tsuyama T, Yamamoto-Kochi M, Sato M, Hattori Y, Sugimura K, Usui T, Kimura KI, Uemura T. Multidendritic sensory neurons in the adult Drosophila abdomen: origins, dendritic morphology, and segment- and age-dependent programmed cell death. Neural Dev 2009; 4:37. [PMID: 19799768 PMCID: PMC2762467 DOI: 10.1186/1749-8104-4-37] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Accepted: 10/02/2009] [Indexed: 12/02/2022] Open
Abstract
Background For the establishment of functional neural circuits that support a wide range of animal behaviors, initial circuits formed in early development have to be reorganized. One way to achieve this is local remodeling of the circuitry hardwiring. To genetically investigate the underlying mechanisms of this remodeling, one model system employs a major group of Drosophila multidendritic sensory neurons - the dendritic arborization (da) neurons - which exhibit dramatic dendritic pruning and subsequent growth during metamorphosis. The 15 da neurons are identified in each larval abdominal hemisegment and are classified into four categories - classes I to IV - in order of increasing size of their receptive fields and/or arbor complexity at the mature larval stage. Our knowledge regarding the anatomy and developmental basis of adult da neurons is still fragmentary. Results We identified multidendritic neurons in the adult Drosophila abdomen, visualized the dendritic arbors of the individual neurons, and traced the origins of those cells back to the larval stage. There were six da neurons in abdominal hemisegment 3 or 4 (A3/4) of the pharate adult and the adult just after eclosion, five of which were persistent larval da neurons. We quantitatively analyzed dendritic arbors of three of the six adult neurons and examined expression in the pharate adult of key transcription factors that result in the larval class-selective dendritic morphologies. The 'baseline design' of A3/4 in the adult was further modified in a segment-dependent and age-dependent manner. One of our notable findings is that a larval class I neuron, ddaE, completed dendritic remodeling in A2 to A4 and then underwent caspase-dependent cell death within 1 week after eclosion, while homologous neurons in A5 and in more posterior segments degenerated at pupal stages. Another finding is that the dendritic arbor of a class IV neuron, v'ada, was immediately reshaped during post-eclosion growth. It exhibited prominent radial-to-lattice transformation in 1-day-old adults, and the resultant lattice-shaped arbor persisted throughout adult life. Conclusion Our study provides the basis on which we can investigate the genetic programs controlling dendritic remodeling and programmed cell death of adult neurons, and the life-long maintenance of dendritic arbors.
Collapse
Affiliation(s)
- Kohei Shimono
- Laboratory of Cell Recognition and Pattern Formation, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|