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Fung W, Kolotuev I, Heiman MG. Specialized structure and function of the apical extracellular matrix at sense organs. Cells Dev 2024; 179:203942. [PMID: 39067521 PMCID: PMC11346620 DOI: 10.1016/j.cdev.2024.203942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/21/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
Apical extracellular matrix (aECM) covers every surface of the body and exhibits tissue-specific structures that carry out specialized functions. This is particularly striking at sense organs, where aECM forms the interface between sensory neurons and the environment, and thus plays critical roles in how sensory stimuli are received. Here, we review the extraordinary adaptations of aECM across sense organs and discuss how differences in protein composition and matrix structure assist in sensing mechanical forces (tactile hairs, campaniform sensilla, and the tectorial membrane of the cochlea); tastes and smells (uniporous gustatory sensilla and multiporous olfactory sensilla in insects, and salivary and olfactory mucus in vertebrates); and light (cuticle-derived lenses in arthropods and mollusks). We summarize the power of using C. elegans, in which defined sense organs associate with distinct aECM, as a model for understanding the tissue-specific structural and functional specializations of aECM. Finally, we synthesize results from recent studies in C. elegans and Drosophila into a conceptual framework for aECM patterning, including mechanisms that involve transient cellular or matrix scaffolds, mechanical pulling or pushing forces, and localized secretion or endocytosis.
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Affiliation(s)
- Wendy Fung
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | | | - Maxwell G Heiman
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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2
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Prelic S, Keesey IW, Lavista-Llanos S, Hansson BS, Wicher D. Innexin expression and localization in the Drosophila antenna indicate gap junction or hemichannel involvement in antennal chemosensory sensilla. Cell Tissue Res 2024:10.1007/s00441-024-03909-3. [PMID: 39174822 DOI: 10.1007/s00441-024-03909-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 07/25/2024] [Indexed: 08/24/2024]
Abstract
Odor detection in insects is largely mediated by structures on antennae called sensilla, which feature a strongly conserved architecture and repertoire of olfactory sensory neurons (OSNs) and various support cell types. In Drosophila, OSNs are tightly apposed to supporting cells, whose connection with neurons and functional roles in odor detection remain unclear. Coupling mechanisms between these neuronal and non-neuronal cell types have been suggested based on morphological observations, concomitant physiological activity during odor stimulation, and known interactions that occur in other chemosensory systems. For instance, it is not known whether cell-cell coupling via gap junctions between OSNs and neighboring cells exists, or whether hemichannels interconnect cellular and extracellular sensillum compartments. Here, we show that innexins, which form hemichannels and gap junctions in invertebrates, are abundantly expressed in adult drosophilid antennae. By surveying antennal transcriptomes and performing various immunohistochemical stainings in antennal tissues, we discover innexin-specific patterns of expression and localization, with a majority of innexins strongly localizing to glial and non-neuronal cells, likely support and epithelial cells. Finally, by injecting gap junction-permeable dye into a pre-identified sensillum, we observe no dye coupling between neuronal and non-neuronal cells. Together with evidence of non-neuronal innexin localization, we conclude that innexins likely do not conjoin neurons to support cells, but that junctions and hemichannels may instead couple support cells among each other or to their shared sensillum lymph to achieve synchronous activity. We discuss how coupling of sensillum microenvironments or compartments may potentially contribute to facilitate chemosensory functions of odor sensing and sensillum homeostasis.
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Affiliation(s)
- Sinisa Prelic
- Dept. Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Ian W Keesey
- Dept. Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sofia Lavista-Llanos
- Dept. Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Bill S Hansson
- Dept. Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Dept. Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany.
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3
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Ghosh N, Treisman JE. Apical cell expansion maintained by Dusky-like establishes a scaffold for corneal lens morphogenesis. SCIENCE ADVANCES 2024; 10:eado4167. [PMID: 39167639 PMCID: PMC11338227 DOI: 10.1126/sciadv.ado4167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 07/11/2024] [Indexed: 08/23/2024]
Abstract
The Drosophila corneal lens is entirely composed of chitin and other apical extracellular matrix components, and it is not known how it acquires the biconvex shape that enables it to focus light onto the retina. We show here that the zona pellucida domain-containing protein Dusky-like is essential for normal corneal lens morphogenesis. Dusky-like transiently localizes to the expanded apical surfaces of the corneal lens-secreting cells and prevents them from undergoing apical constriction and apicobasal contraction. Dusky-like also controls the arrangement of two other zona pellucida domain proteins, Dumpy and Piopio, external to the developing corneal lens. Loss of either dusky-like or dumpy delays chitin accumulation and disrupts the outer surface of the corneal lens. We find that artificially inducing apical constriction by activating myosin contraction is sufficient to similarly alter chitin deposition and corneal lens morphology. These results demonstrate the importance of cell shape in controlling the morphogenesis of overlying apical extracellular matrix structures such as the corneal lens.
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Affiliation(s)
- Neha Ghosh
- Department of Cell Biology, NYU Grossman School of Medicine, 540 First Avenue, New York, NY 10016, USA
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4
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Zhang L, Ge R, Yang Y, Chen K, Li C. The zona pellucida protein piopio regulates the metamorphosis and reproduction in Tribolium castaneum. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2024; 116:e22122. [PMID: 38783685 DOI: 10.1002/arch.22122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/09/2024] [Accepted: 05/16/2024] [Indexed: 05/25/2024]
Abstract
The zona pellucida domain protein piopio (Pio) was only reported to mediate the adhesion of the apical epithelial surface and the overlying apical extracellular matrix in Drosophila melanogaster, but the developmental roles of Pio were poorly understood in insects. To address this issue, we comprehensively analyzed the function of Pio in Tribolium castaneum. Phylogenetic analysis indicated that pio exhibited one-to-one orthologous relationship among insects. T. castaneum pio had a 1236-bp ORF and contained eight exons. During development pio was abundantly expressed from larva to adult and lowly expressed at the late stage of embryo and adult, while it had more transcripts in the head, epidermis, and gut but fewer in the fat body of late-stage larvae. Knockdown of pio inhibited the pupation, eclosion, and reproduction of T. castaneum. The expression of vitellogenin 1 (Vg1), Vg2, and Vg receptor (VgR) largely decreased in pio-silenced female adults. Silencing pio increased the 20-hydroxyecdysone titer by upregulating phm and spo expression but decreased the juvenile hormone (JH) titer through downregulating JHAMT3 and promoting JHE, JHEH-r4, and JHDK transcription. These results suggested that Pio might regulate the metamorphosis and reproduction via modulating the ecdysone and JH metabolism in T. castaneum. This study found the novel roles of pio in insect metamorphosis and reproduction, and provided the new insights for analyzing other zona pellucida proteins functions in insects.
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Affiliation(s)
- Ling Zhang
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Runting Ge
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yanhua Yang
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Chengjun Li
- School of Life Sciences, Jiangsu University, Zhenjiang, China
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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5
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Ghosh N, Treisman JE. Apical cell expansion maintained by Dusky-like establishes a scaffold for corneal lens morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.575959. [PMID: 38293108 PMCID: PMC10827211 DOI: 10.1101/2024.01.17.575959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The biconvex shape of the Drosophila corneal lens, which enables it to focus light onto the retina, arises by organized assembly of chitin and other apical extracellular matrix components. We show here that the Zona Pellucida domain-containing protein Dusky-like is essential for normal corneal lens morphogenesis. Dusky-like transiently localizes to the expanded apical surfaces of the corneal lens-secreting cells, and in its absence, these cells undergo apical constriction and apicobasal contraction. Dusky-like also controls the arrangement of two other Zona Pellucida-domain proteins, Dumpy and Piopio, external to the developing corneal lens. Loss of either dusky-like or dumpy delays chitin accumulation and disrupts the outer surface of the corneal lens. Artificially inducing apical constriction with constitutively active Myosin light chain kinase is sufficient to similarly alter chitin deposition and corneal lens morphology. These results demonstrate the importance of cell shape for the morphogenesis of overlying apical extracellular matrix structures.
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6
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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Zhang B, Duan H, Kavaler J, Wei L, Eberl DF, Lai EC. A nonneural miRNA cluster mediates hearing via repression of two neural targets. Genes Dev 2023; 37:1041-1051. [PMID: 38110249 PMCID: PMC10760640 DOI: 10.1101/gad.351052.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/29/2023] [Indexed: 12/20/2023]
Abstract
We show here that mir-279/996 are absolutely essential for development and function of Johnston's organ (JO), the primary proprioceptive and auditory organ in Drosophila Their deletion results in highly aberrant cell fate determination, including loss of scolopale cells and ectopic neurons, and mutants are electrophysiologically deaf. In vivo activity sensors and mosaic analyses indicate that these seed-related miRNAs function autonomously to suppress neural fate in nonneuronal cells. Finally, genetic interactions pinpoint two neural targets (elav and insensible) that underlie miRNA mutant JO phenotypes. This work uncovers how critical post-transcriptional regulation of specific miRNA targets governs cell specification and function of the auditory system.
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Affiliation(s)
- Binglong Zhang
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Hong Duan
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Joshua Kavaler
- Department of Biology, Colby College, Waterville, Maine 04901, USA
| | - Lu Wei
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Daniel F Eberl
- Department of Biology, University of Iowa, Iowa City, Iowa 52242, USA
| | - Eric C Lai
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA;
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Song X, Cui L, Wu M, Wang S, Song Y, Liu Z, Xue Z, Chen W, Zhang Y, Li H, Sun L, Liang X. DCX-EMAP is a core organizer for the ultrastructure of Drosophila mechanosensory organelles. J Cell Biol 2023; 222:e202209116. [PMID: 37651176 PMCID: PMC10471123 DOI: 10.1083/jcb.202209116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 06/21/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Mechanoreceptor cells develop specialized mechanosensory organelles (MOs), where force-sensitive channels and supporting structures are organized in an orderly manner to detect forces. It is intriguing how MOs are formed. Here, we address this issue by studying the MOs of fly ciliated mechanoreceptors. We show that the main structure of the MOs is a compound cytoskeleton formed of short microtubules and electron-dense materials (EDMs). In a knock-out mutant of DCX-EMAP, this cytoskeleton is nearly absent, suggesting that DCX-EMAP is required for the formation of the MOs and in turn fly mechanotransduction. Further analysis reveals that DCX-EMAP expresses in fly ciliated mechanoreceptors and localizes to the MOs. Moreover, it plays dual roles by promoting the assembly/stabilization of the microtubules and the accumulation of the EDMs in the MOs. Therefore, DCX-EMAP serves as a core ultrastructural organizer of the MOs, and this finding provides novel molecular insights as to how fly MOs are formed.
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Affiliation(s)
- Xuewei Song
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lihong Cui
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Menghua Wu
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shan Wang
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yinlong Song
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhen Liu
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhaoyu Xue
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wei Chen
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yingjie Zhang
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Hui Li
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Landi Sun
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
- Guangzhou Laboratory, Guangzhou, China
| | - Xin Liang
- IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
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9
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Sharma Y, Jacobs JS, Sivan-Loukianova E, Lee E, Kernan MJ, Eberl DF. The retrograde IFT dynein is required for normal function of diverse mechanosensory cilia in Drosophila. Front Mol Neurosci 2023; 16:1263411. [PMID: 37808471 PMCID: PMC10556659 DOI: 10.3389/fnmol.2023.1263411] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/07/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Cilia biogenesis relies on intraflagellar transport (IFT), a conserved transport mechanism which functions bi-directionally to bring protein complexes to the growing ciliary tip and recycle signaling and transport proteins between the cilium and cell body. In Drosophila, anterograde IFT is critical for assembly of sensory cilia in the neurons of both chordotonal (ch) organs, which have relatively long ciliary axonemes, and external sensory (es) organs, which have short axonemal segments with microtubules in distal sensory segments forming non-axonemal bundles. We previously isolated the beethoven (btv) mutant in a mutagenesis screen for auditory mutants. Although many btv mutant flies are deaf, some retain a small residual auditory function as determined both by behavior and by auditory electrophysiology. Results Here we molecularly characterize the btv gene and demonstrate that it encodes the IFT-associated dynein-2 heavy chain Dync2h1. We also describe morphological changes in Johnston's organ as flies age to 30 days, and we find that morphological and electrophysiological phenotypes in this ch organ of btv mutants become more severe with age. We show that NompB protein, encoding the conserved IFT88 protein, an IFT complex B component, fails to be cleared from chordotonal cilia in btv mutants, instead accumulating in the distorted cilia. In macrochaete bristles, a class of es organ, btv mutants show a 50% reduction in mechanoreceptor potentials. Discussion Thus, the btv-encoded Dync2h1 functions as the retrograde IFT motor in the assembly of long ciliary axonemes in ch organs and is also important for normal function of the short ciliary axonemes in es organs.
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Affiliation(s)
- Yashoda Sharma
- Department of Biology, The University of Iowa, Iowa City, IA, United States
| | - Julie S. Jacobs
- Department of Biology, The University of Iowa, Iowa City, IA, United States
| | | | - Eugene Lee
- Department of Neurobiology and Behavior, State University of New York, Stony Brook, NY, United States
| | - Maurice J. Kernan
- Department of Neurobiology and Behavior, State University of New York, Stony Brook, NY, United States
| | - Daniel F. Eberl
- Department of Biology, The University of Iowa, Iowa City, IA, United States
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10
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Ha TS, Sengupta S, Powell J, Smith DP. An angiotensin converting enzyme homolog is required for volatile pheromone detection, odorant binding protein secretion and normal courtship behavior in Drosophila melanogaster. Genetics 2023; 224:iyad109. [PMID: 37283550 PMCID: PMC10484059 DOI: 10.1093/genetics/iyad109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/23/2023] [Accepted: 05/30/2023] [Indexed: 06/08/2023] Open
Abstract
In many arthropods, including insects responsible for transmission of human diseases, behaviors that include mating, aggregation, and aggression are triggered by detection of pheromones. Extracellular odorant binding proteins are critical for pheromone detection in many insects and are secreted into the fluid bathing the olfactory neuron dendrites. In Drosophila melanogaster, the odorant binding protein LUSH is essential for normal sensitivity to the volatile sex pheromone, 11-cis vaccenyl acetate (cVA). Using a genetic screen for cVA pheromone insensitivity, we identified ANCE-3, a homolog of human angiotensin converting enzyme that is required for detection of cVA pheromone. The mutants have normal dose-response curves for food odors, although olfactory neuron amplitudes are reduced in all olfactory neurons examined. ance-3 mutants have profound delays in mating, and the courtship defects are primarily but not exclusively due to loss of ance-3 function in males. We demonstrate that ANCE-3 is required in the sensillae support cells for normal reproductive behavior, and that localization of odorant binding proteins to the sensillum lymph is blocked in the mutants. Expression of an ance-3 cDNA in sensillae support cells completely rescues the cVA responses, LUSH localization, and courtship defects. We show the courtship latency defects are not due to effects on olfactory neurons in the antenna nor mediated through ORCO receptors, but instead stem from ANCE-3-dependent effects on chemosensory sensillae in other body parts. These findings reveal an unexpected factor critical for pheromone detection with profound influence on reproductive behaviors.
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Affiliation(s)
- Tal Soo Ha
- Department of Biomedical Science, Daegu University, 201 Daegudae-ro, Gyeongsan-si, Gyeongbuk, 38453 Republic of Korea
| | - Samarpita Sengupta
- Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
- Department of Physician Assistant Studies, School of Health Professions, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
| | - Jordan Powell
- Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
| | - Dean P Smith
- Department of Pharmacology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
- Department of Neuroscience, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
- O’Donnell Brain Institute, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
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11
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Hopkins BR, Barmina O, Kopp A. A single-cell atlas of the sexually dimorphic Drosophila foreleg and its sensory organs during development. PLoS Biol 2023; 21:e3002148. [PMID: 37379332 DOI: 10.1371/journal.pbio.3002148] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/03/2023] [Indexed: 06/30/2023] Open
Abstract
To respond to the world around them, animals rely on the input of a network of sensory organs distributed throughout the body. Distinct classes of sensory organs are specialized for the detection of specific stimuli such as strain, pressure, or taste. The features that underlie this specialization relate both to the neurons that innervate sensory organs and the accessory cells they comprise. To understand the genetic basis of this diversity of cell types, both within and between sensory organs, we performed single-cell RNA sequencing on the first tarsal segment of the male Drosophila melanogaster foreleg during pupal development. This tissue displays a wide variety of functionally and structurally distinct sensory organs, including campaniform sensilla, mechanosensory bristles, and chemosensory taste bristles, as well as the sex comb, a recently evolved male-specific structure. In this study, we characterize the cellular landscape in which the sensory organs reside, identify a novel cell type that contributes to the construction of the neural lamella, and resolve the transcriptomic differences among support cells within and between sensory organs. We identify the genes that distinguish between mechanosensory and chemosensory neurons, resolve a combinatorial transcription factor code that defines 4 distinct classes of gustatory neurons and several types of mechanosensory neurons, and match the expression of sensory receptor genes to specific neuron classes. Collectively, our work identifies core genetic features of a variety of sensory organs and provides a rich, annotated resource for studying their development and function.
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Affiliation(s)
- Ben R Hopkins
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Olga Barmina
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
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12
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Scalzotto M, Ng R, Cruchet S, Saina M, Armida J, Su CY, Benton R. Pheromone sensing in Drosophila requires support cell-expressed Osiris 8. BMC Biol 2022; 20:230. [PMID: 36217142 PMCID: PMC9552441 DOI: 10.1186/s12915-022-01425-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background The nose of most animals comprises multiple sensory subsystems, which are defined by the expression of different olfactory receptor families. Drosophila melanogaster antennae contain two morphologically and functionally distinct subsystems that express odorant receptors (Ors) or ionotropic receptors (Irs). Although these receptors have been thoroughly characterized in this species, the subsystem-specific expression and roles of other genes are much less well-understood. Results Here we generate subsystem-specific transcriptomic datasets to identify hundreds of genes, encoding diverse protein classes, that are selectively enriched in either Or or Ir subsystems. Using single-cell antennal transcriptomic data and RNA in situ hybridization, we find that most neuronal genes—other than sensory receptor genes—are broadly expressed within the subsystems. By contrast, we identify many non-neuronal genes that exhibit highly selective expression, revealing substantial molecular heterogeneity in the non-neuronal cellular components of the olfactory subsystems. We characterize one Or subsystem-specific non-neuronal molecule, Osiris 8 (Osi8), a conserved member of a large, insect-specific family of transmembrane proteins. Osi8 is expressed in the membranes of tormogen support cells of pheromone-sensing trichoid sensilla. Loss of Osi8 does not have obvious impact on trichoid sensillar development or basal neuronal activity, but abolishes high sensitivity responses to pheromone ligands. Conclusions This work identifies a new protein required for insect pheromone detection, emphasizes the importance of support cells in neuronal sensory functions, and provides a resource for future characterization of other olfactory subsystem-specific genes. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01425-w.
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Affiliation(s)
- Marta Scalzotto
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Renny Ng
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Steeve Cruchet
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Michael Saina
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Jan Armida
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Chih-Ying Su
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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13
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Almazán A, Çevrim Ç, Musser JM, Averof M, Paris M. Crustacean leg regeneration restores complex microanatomy and cell diversity. SCIENCE ADVANCES 2022; 8:eabn9823. [PMID: 36001670 PMCID: PMC9401613 DOI: 10.1126/sciadv.abn9823] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Animals can regenerate complex organs, yet this process frequently results in imprecise replicas of the original structure. In the crustacean Parhyale, embryonic and regenerating legs differ in gene expression dynamics but produce apparently similar mature structures. We examine the fidelity of Parhyale leg regeneration using complementary approaches to investigate microanatomy, sensory function, cellular composition, and cell molecular profiles. We find that regeneration precisely replicates the complex microanatomy and spatial distribution of external sensory organs and restores their sensory function. Single-nuclei sequencing shows that regenerated and uninjured legs are indistinguishable in terms of cell-type composition and transcriptional profiles. This remarkable fidelity highlights the ability of organisms to achieve identical outcomes via distinct processes.
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Affiliation(s)
- Alba Almazán
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Çağrı Çevrim
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Jacob M. Musser
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Michalis Averof
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
| | - Mathilde Paris
- Institut de Génomique Fonctionnelle de Lyon (IGFL), Centre National de la Recherche Scientifique (CNRS), École Normale Supérieure de Lyon and Université Claude Bernard Lyon 1, 69007 Lyon, France
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14
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Xiang W, Zur Lage P, Newton FG, Qiu G, Jarman AP. The dynamics of protein localisation to restricted zones within Drosophila mechanosensory cilia. Sci Rep 2022; 12:13338. [PMID: 35922464 PMCID: PMC9349282 DOI: 10.1038/s41598-022-17189-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/21/2022] [Indexed: 12/02/2022] Open
Abstract
The Drosophila chordotonal neuron cilium is the site of mechanosensory transduction. The cilium has a 9 + 0 axoneme structure and is highly sub-compartmentalised, with proximal and distal zones harbouring different TRP channels and the proximal zone axoneme also being decorated with axonemal dynein motor complexes. The activity of the dynein complexes is essential for mechanotransduction. We investigate the localisation of TRP channels and dynein motor complexes during ciliogenesis. Differences in timing of TRP channel localisation correlate with order of construction of the two ciliary zones. Dynein motor complexes are initially not confined to their target proximal zone, but ectopic complexes beyond the proximal zone are later cleared, perhaps by retrograde transport. Differences in transient distal localisation of outer and inner dynein arm complexes (ODAs and IDAs) are consistent with previous suggestions from unicellular eukaryotes of differences in processivity during intraflagellar transport. Stable localisation depends on the targeting of their docking proteins in the proximal zone. For ODA, we characterise an ODA docking complex (ODA-DC) that is targeted directly to the proximal zone. Interestingly, the subunit composition of the ODA-DC in chordotonal neuron cilia appears to be different from the predicted ODA-DC in Drosophila sperm.
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Affiliation(s)
- Wangchu Xiang
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK.,Department of Neurobiology, Harvard Medical School, Boston, MA, 02215, USA
| | - Petra Zur Lage
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Fay G Newton
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK.,Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Guiyun Qiu
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK.,Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh BioQuarter, 5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Andrew P Jarman
- Centre for Discovery Brain Sciences, Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD, UK.
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15
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Prelic S, Pal Mahadevan V, Venkateswaran V, Lavista-Llanos S, Hansson BS, Wicher D. Functional Interaction Between Drosophila Olfactory Sensory Neurons and Their Support Cells. Front Cell Neurosci 2022; 15:789086. [PMID: 35069116 PMCID: PMC8777253 DOI: 10.3389/fncel.2021.789086] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/15/2021] [Indexed: 01/14/2023] Open
Abstract
Insects detect volatile chemicals using antennae, which house a vast variety of olfactory sensory neurons (OSNs) that innervate hair-like structures called sensilla where odor detection takes place. In addition to OSNs, the antenna also hosts various support cell types. These include the triad of trichogen, tormogen, and thecogen support cells that lie adjacent to their respective OSNs. The arrangement of OSN supporting cells occurs stereotypically for all sensilla and is widely conserved in evolution. While insect chemosensory neurons have received considerable attention, little is known about the functional significance of the cells that support them. For instance, it remains unknown whether support cells play an active role in odor detection, or only passively contribute to homeostasis, e.g., by maintaining sensillum lymph composition. To investigate the functional interaction between OSNs and support cells, we used optical and electrophysiological approaches in Drosophila. First, we characterized the distribution of various supporting cells using genetic markers. By means of an ex vivo antennal preparation and genetically-encoded Ca2+ and K+ indicators, we then studied the activation of these auxiliary cells during odor presentation in adult flies. We observed acute responses and distinct differences in Ca2+ and K+ fluxes between support cell types. Finally, we observed alterations in OSN responses upon thecogen cell ablation in mature adults. Upon inducible ablation of thecogen cells, we notice a gain in mechanical responsiveness to mechanical stimulations during single-sensillum recording, but a lack of change to the neuronal resting activity. Taken together, these results demonstrate that support cells play a more active and responsive role during odor processing than previously thought. Our observations thus reveal that support cells functionally interact with OSNs and may be important for the extraordinary ability of insect olfactory systems to dynamically and sensitively discriminate between odors in the turbulent sensory landscape of insect flight.
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Affiliation(s)
- Sinisa Prelic
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Venkatesh Pal Mahadevan
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Vignesh Venkateswaran
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Sofia Lavista-Llanos
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
- CIFASIS-CONICET Franco-Argentine International Center for Information and Systems Sciences—National Council for Scientific and Technical Research, Rosario, Argentina
| | - Bill S. Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
- *Correspondence: Dieter Wicher
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16
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Yang T, Yuan Z, Liu C, Liu T, Zhang W. A neural circuit integrates pharyngeal sensation to control feeding. Cell Rep 2021; 37:109983. [PMID: 34758309 DOI: 10.1016/j.celrep.2021.109983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 08/20/2021] [Accepted: 10/20/2021] [Indexed: 11/18/2022] Open
Abstract
Swallowing is an essential step of eating and drinking. However, how the quality of a food bolus is sensed by pharyngeal neurons is largely unknown. Here we find that mechanical receptors along the Drosophila pharynx are required for control of meal size, especially for food of high viscosity. The mechanical force exerted by the bolus passing across the pharynx is detected by neurons expressing the mechanotransduction channel NOMPC (no mechanoreceptor potential C) and is relayed, together with gustatory information, to IN1 neurons in the subesophageal zone (SEZ) of the brain. IN1 (ingestion neurons) neurons act directly upstream of a group of peptidergic neurons that encode satiety. Prolonged activation of IN1 neurons suppresses feeding. IN1 neurons receive inhibition from DSOG1 (descending subesophageal neurons) neurons, a group of GABAergic neurons that non-selectively suppress feeding. Our results reveal the function of pharyngeal mechanoreceptors and their downstream neural circuits in the control of food ingestion.
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Affiliation(s)
- Tingting Yang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Zixuan Yuan
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Chenxi Liu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Ting Liu
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Wei Zhang
- School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China.
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17
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Warren B, Nowotny M. Bridging the Gap Between Mammal and Insect Ears – A Comparative and Evolutionary View of Sound-Reception. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.667218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insects must wonder why mammals have ears only in their head and why they evolved only one common principle of ear design—the cochlea. Ears independently evolved at least 19 times in different insect groups and therefore can be found in completely different body parts. The morphologies and functional characteristics of insect ears are as wildly diverse as the ecological niches they exploit. In both, insects and mammals, hearing organs are constrained by the same biophysical principles and their respective molecular processes for mechanotransduction are thought to share a common evolutionary origin. Due to this, comparative knowledge of hearing across animal phyla provides crucial insight into fundamental processes of auditory transduction, especially at the biomechanical and molecular level. This review will start by comparing hearing between insects and mammals in an evolutionary context. It will then discuss current findings about sound reception will help to bridge the gap between both research fields.
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18
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Arguello JR, Abuin L, Armida J, Mika K, Chai PC, Benton R. Targeted molecular profiling of rare olfactory sensory neurons identifies fate, wiring, and functional determinants. eLife 2021; 10:63036. [PMID: 33666172 PMCID: PMC7993999 DOI: 10.7554/elife.63036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 03/04/2021] [Indexed: 02/06/2023] Open
Abstract
Determining the molecular properties of neurons is essential to understand their development, function and evolution. Using Targeted DamID (TaDa), we characterize RNA polymerase II occupancy and chromatin accessibility in selected Ionotropic receptor (Ir)-expressing olfactory sensory neurons in Drosophila. Although individual populations represent a minute fraction of cells, TaDa is sufficiently sensitive and specific to identify the expected receptor genes. Unique Ir expression is not consistently associated with differences in chromatin accessibility, but rather to distinct transcription factor profiles. Genes that are heterogeneously expressed across populations are enriched for neurodevelopmental factors, and we identify functions for the POU-domain protein Pdm3 as a genetic switch of Ir neuron fate, and the atypical cadherin Flamingo in segregation of neurons into discrete glomeruli. Together this study reveals the effectiveness of TaDa in profiling rare neural populations, identifies new roles for a transcription factor and a neuronal guidance molecule, and provides valuable datasets for future exploration.
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Affiliation(s)
- J Roman Arguello
- Center for Integrative Genomics Faculty of Biology and Medicine University of Lausanne, Lausanne, Switzerland.,Department of Ecology and Evolution Faculty of Biology and Medicine University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Liliane Abuin
- Center for Integrative Genomics Faculty of Biology and Medicine University of Lausanne, Lausanne, Switzerland
| | - Jan Armida
- Center for Integrative Genomics Faculty of Biology and Medicine University of Lausanne, Lausanne, Switzerland
| | - Kaan Mika
- Center for Integrative Genomics Faculty of Biology and Medicine University of Lausanne, Lausanne, Switzerland
| | - Phing Chian Chai
- 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
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19
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Schwaller F, Bégay V, García-García G, Taberner FJ, Moshourab R, McDonald B, Docter T, Kühnemund J, Ojeda-Alonso J, Paricio-Montesinos R, Lechner SG, Poulet JFA, Millan JM, Lewin GR. USH2A is a Meissner's corpuscle protein necessary for normal vibration sensing in mice and humans. Nat Neurosci 2021. [PMID: 33288907 DOI: 10.1101/2020.07.01.180919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Fingertip mechanoreceptors comprise sensory neuron endings together with specialized skin cells that form the end-organ. Exquisitely sensitive, vibration-sensing neurons are associated with Meissner's corpuscles in the skin. In the present study, we found that USH2A, a transmembrane protein with a very large extracellular domain, was found in terminal Schwann cells within Meissner's corpuscles. Pathogenic USH2A mutations cause Usher's syndrome, associated with hearing loss and visual impairment. We show that patients with biallelic pathogenic USH2A mutations also have clear and specific impairments in vibrotactile touch perception, as do mutant mice lacking USH2A. Forepaw rapidly adapting mechanoreceptors innervating Meissner's corpuscles, recorded from Ush2a-/- mice, showed large reductions in vibration sensitivity. However, the USH2A protein was not found in sensory neurons. Thus, loss of USH2A in corpuscular end-organs reduced mechanoreceptor sensitivity as well as vibration perception. Thus, a tether-like protein is required to facilitate detection of small-amplitude vibrations essential for the perception of fine-grained tactile surfaces.
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Affiliation(s)
- Fred Schwaller
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Valérie Bégay
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Gema García-García
- Research Group on Molecular, Cellular and Genomic Biomedicine Health Research, Institute La Fe and Joint Unit for Rare Diseases CIPF-IIS La Fe, Valencia, Spain
- Center for Biomedical Network Research on Rare Diseases, Institute of Health Carlos III, Madrid, Spain
| | - Francisco J Taberner
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
| | - Rabih Moshourab
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Department of Anesthesiology and Operative Intensive Care Medicine, Campus Virchow Klinikum and Campus Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Department of Anesthesiology, Helios Klinikum Erfurt, Erfurt, Germany
| | - Brennan McDonald
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Trevor Docter
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Department of Molecular and Cellular Biology at Life Sciences Addition, University of California at Berkeley, Berkeley, CA, USA
| | - Johannes Kühnemund
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Julia Ojeda-Alonso
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Ricardo Paricio-Montesinos
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
| | - Stefan G Lechner
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - James F A Poulet
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Neuroscience Research Center, Charité-Universitätsmedizin, Berlin, Germany
| | - Jose M Millan
- Research Group on Molecular, Cellular and Genomic Biomedicine Health Research, Institute La Fe and Joint Unit for Rare Diseases CIPF-IIS La Fe, Valencia, Spain
- Center for Biomedical Network Research on Rare Diseases, Institute of Health Carlos III, Madrid, Spain
| | - Gary R Lewin
- Department of Neuroscience, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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20
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Kwon Y, Lee J, Chung YD. Sub-Ciliary Segregation of Two Drosophila Transient Receptor Potential Channels Begins at the Initial Stage of Their Pre-Ciliary Trafficking. Mol Cells 2020; 43:1002-1010. [PMID: 33323559 PMCID: PMC7772507 DOI: 10.14348/molcells.2020.0205] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/15/2020] [Accepted: 11/15/2020] [Indexed: 12/14/2022] Open
Abstract
Cilia are important eukaryotic cellular compartments required for diverse biological functions. Recent studies have revealed that protein targeting into the proper ciliary subcompartments is essential for ciliary function. In Drosophila chordotonal cilium, where mechano-electric transduction occurs, two transient receptor potential (TRP) superfamily ion channels, TRPV and TRPN, are restricted to the proximal and distal subcompartments, respectively. To understand the mechanisms underlying the sub-ciliary segregation of the two TRPs, we analyzed their localization under various conditions. In developing chordotonal cilia, TRPN was directly targeted to the ciliary tip from the beginning of its appearance and was retained in the distal subcompartment throughout development, whereas the ciliary localization of TRPV was considerably delayed. Lack of intraflagella transport-related proteins affected TRPV from the initial stage of its pre-ciliary trafficking, whereas it affected TRPN from the ciliary entry stage. The ectopic expression of the two TRP channels in both ciliated and nonciliated cells revealed their intrinsic properties related to their localization. Taken together, our results suggest that subciliary segregation of the two TRP channels relies on their distinct intrinsic properties, and begins at the initial stage of their pre-ciliary trafficking.
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Affiliation(s)
- Youngtae Kwon
- Department of Life Sciences, University of Seoul, Seoul 02504, Korea
| | - Jeongmi Lee
- Department of Life Sciences, University of Seoul, Seoul 02504, Korea
| | - Yun Doo Chung
- Department of Life Sciences, University of Seoul, Seoul 02504, Korea
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21
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Schwaller F, Bégay V, García-García G, Taberner FJ, Moshourab R, McDonald B, Docter T, Kühnemund J, Ojeda-Alonso J, Paricio-Montesinos R, Lechner SG, Poulet JFA, Millan JM, Lewin GR. USH2A is a Meissner’s corpuscle protein necessary for normal vibration sensing in mice and humans. Nat Neurosci 2020; 24:74-81. [DOI: 10.1038/s41593-020-00751-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 10/30/2020] [Indexed: 12/29/2022]
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22
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Hassan A, Sapir L, Nitsan I, Greenblatt Ben-El RT, Halachmi N, Salzberg A, Tzlil S. A Change in ECM Composition Affects Sensory Organ Mechanics and Function. Cell Rep 2020; 27:2272-2280.e4. [PMID: 31116974 DOI: 10.1016/j.celrep.2019.04.092] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 02/12/2019] [Accepted: 04/18/2019] [Indexed: 11/26/2022] Open
Abstract
Proprioception requires the transduction of muscle-generated deformations into sensory neuronal impulses. In proprioceptive organs, the mechanical coupling between the sensory neuron and the muscle is mediated by a connective structure composed of accessory cells and an extracellular matrix (ECM). Here, we use the fly chordotonal organ (ChO) to investigate how the mechanical properties of the connective element affect mechanosensing. We show that the loss of Pericardin, a major constituent of the ChO ECM, alters the mechanical properties of the ChO resulting in short-wavelength buckling of the accessory cells upon muscle contraction and low compressive strain within the organ. We explain these results using a simplified theoretical model of an elastic beam interacting with an elastic network under a compressive force. We further demonstrate that the transition from compression to bending interferes with the ability of the accessory cells to propagate muscle-generated deformations correctly to the neuron and hence with proper sensing.
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Affiliation(s)
- Abeer Hassan
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Liel Sapir
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Ido Nitsan
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Rina T Greenblatt Ben-El
- Department of Genetics and Developmental Biology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa 3109601, Israel
| | - Naomi Halachmi
- Department of Genetics and Developmental Biology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa 3109601, Israel
| | - Adi Salzberg
- Department of Genetics and Developmental Biology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa 3109601, Israel
| | - Shelly Tzlil
- Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
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23
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Jin P, Jan LY, Jan YN. Mechanosensitive Ion Channels: Structural Features Relevant to Mechanotransduction Mechanisms. Annu Rev Neurosci 2020; 43:207-229. [PMID: 32084327 DOI: 10.1146/annurev-neuro-070918-050509] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Activation of mechanosensitive ion channels underlies a variety of fundamental physiological processes that require sensation of mechanical force. Different mechanosensitive channels adapt distinctive structures and mechanotransduction mechanisms to fit their biological roles. How mechanosensitive channels work, especially in animals, has been extensively studied in the past decade. Here we review key findings in the functional and structural characterizations of these channels and highlight the structural features relevant to the mechanotransduction mechanism of each specific channel.
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Affiliation(s)
- Peng Jin
- Department of Physiology, University of California, San Francisco, California 94158, USA;
| | - Lily Yeh Jan
- Department of Physiology, University of California, San Francisco, California 94158, USA; .,Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA
| | - Yuh-Nung Jan
- Department of Physiology, University of California, San Francisco, California 94158, USA; .,Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA
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24
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Cohen JD, Flatt KM, Schroeder NE, Sundaram MV. Epithelial Shaping by Diverse Apical Extracellular Matrices Requires the Nidogen Domain Protein DEX-1 in Caenorhabditis elegans. Genetics 2019; 211:185-200. [PMID: 30409789 PMCID: PMC6325709 DOI: 10.1534/genetics.118.301752] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/05/2018] [Indexed: 02/06/2023] Open
Abstract
The body's external surfaces and the insides of biological tubes, like the vascular system, are lined by a lipid-, glycoprotein-, and glycosaminoglycan-rich apical extracellular matrix (aECM). aECMs are the body's first line of defense against infectious agents and promote tissue integrity and morphogenesis, but are poorly described relative to basement membranes and stromal ECMs. While some aECM components, such as zona pellucida (ZP) domain proteins, have been identified, little is known regarding the overall composition of the aECM or the mechanisms by which different aECM components work together to shape epithelial tissues. In Caenorhabditis elegans, external epithelia develop in the context of an ill-defined ZP-containing aECM that precedes secretion of the collagenous cuticle. C. elegans has 43 genes that encode at least 65 unique ZP proteins, and we show that some of these comprise distinct precuticle aECMs in the embryo. Previously, the nidogen- and EGF-domain protein DEX-1 was shown to anchor dendrites to the C. elegans nose tip in concert with the ZP protein DYF-7 Here, we identified a new, strong loss-of-function allele of dex-1, cs201dex-1 mutants die as L1 larvae and have a variety of tissue distortion phenotypes, including excretory defects, pharyngeal ingression, alae defects, and a short and fat body shape, that strongly resemble those of genes encoding ZP proteins. DEX-1 localizes to ZP-containing aECMs in the tissues that show defects in dex-1 mutants. Our studies suggest that DEX-1 is a component of multiple distinct embryonic aECMs that shape developing epithelia, and a potential partner of multiple ZP proteins.
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Affiliation(s)
- Jennifer D Cohen
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Kristen M Flatt
- Program in Neuroscience, University of Illinois at Urbana-Champaign, Illinois 61801-4730
| | - Nathan E Schroeder
- Program in Neuroscience, University of Illinois at Urbana-Champaign, Illinois 61801-4730
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Illinois 61801-4730
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
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25
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Pei J, Kinch LN, Grishin NV. FlyXCDB—A Resource for Drosophila Cell Surface and Secreted Proteins and Their Extracellular Domains. J Mol Biol 2018; 430:3353-3411. [DOI: 10.1016/j.jmb.2018.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 05/31/2018] [Accepted: 06/02/2018] [Indexed: 02/06/2023]
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26
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Li T, Bellen HJ, Groves AK. Using Drosophila to study mechanisms of hereditary hearing loss. Dis Model Mech 2018; 11:11/6/dmm031492. [PMID: 29853544 PMCID: PMC6031363 DOI: 10.1242/dmm.031492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Johnston's organ - the hearing organ of Drosophila - has a very different structure and morphology to that of the hearing organs of vertebrates. Nevertheless, it is becoming clear that vertebrate and invertebrate auditory organs share many physiological, molecular and genetic similarities. Here, we compare the molecular and cellular features of hearing organs in Drosophila with those of vertebrates, and discuss recent evidence concerning the functional conservation of Usher proteins between flies and mammals. Mutations in Usher genes cause Usher syndrome, the leading cause of human deafness and blindness. In Drosophila, some Usher syndrome proteins appear to physically interact in protein complexes that are similar to those described in mammals. This functional conservation highlights a rational role for Drosophila as a model for studying hearing, and for investigating the evolution of auditory organs, with the aim of advancing our understanding of the genes that regulate human hearing and the pathogenic mechanisms that lead to deafness.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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27
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Abstract
All animal oocytes are surrounded by a glycoproteinaceous egg coat, a specialized extracellular matrix that serves both structural and species-specific roles during fertilization. Egg coat glycoproteins polymerize into the extracellular matrix of the egg coat using a conserved protein-protein interaction module-the zona pellucida (ZP) domain-common to both vertebrates and invertebrates, suggesting that the basic structural features of egg coats have been conserved across hundreds of millions of years of evolution. Egg coat proteins, as with other proteins involved in reproduction, are frequently found to be rapidly evolving. Given that gamete compatibility must be maintained for the fitness of sexually reproducing organisms, this finding is somewhat paradoxical and suggests a role for adaptive diversification in reproductive protein evolution. Here we review the structure and function of metazoan egg coat proteins, with an emphasis on the potential role their evolution has played in the creation and maintenance of species boundaries.
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Affiliation(s)
- Emily E Killingbeck
- Department of Genome Sciences, University of Washington, Seattle, WA, United States.
| | - Willie J Swanson
- Department of Genome Sciences, University of Washington, Seattle, WA, United States.
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28
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Kavaler J, Duan H, Aradhya R, de Navas LF, Joseph B, Shklyar B, Lai EC. miRNA suppression of a Notch repressor directs non-neuronal fate in Drosophila mechanosensory organs. J Cell Biol 2017; 217:571-583. [PMID: 29196461 PMCID: PMC5800810 DOI: 10.1083/jcb.201706101] [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: 06/16/2017] [Revised: 10/12/2017] [Accepted: 11/08/2017] [Indexed: 12/19/2022] Open
Abstract
Large-scale knockout studies suggest that most miRNAs are phenotypically dispensable. However, Kavaler et al. show here that developmental specification toward a non-neuronal fate in the Drosophila melanogaster peripheral sensory organ lineage depends critically on mir-279/996 repression of the Notch repressor Insensible. Although there is abundant evidence that individual microRNA (miRNA) loci repress large cohorts of targets, large-scale knockout studies suggest that most miRNAs are phenotypically dispensable. Here, we identify a rare case of developmental cell specification that is highly dependent on miRNA control of an individual target. We observe that binary cell fate choice in the Drosophila melanogaster peripheral sensory organ lineage is controlled by the non-neuronally expressed mir-279/996 cluster, with a majority of notum sensory organs exhibiting transformation of sheath cells into ectopic neurons. The mir-279/996 defect phenocopies Notch loss of function during the sheath–neuron cell fate decision, suggesting the miRNAs facilitate Notch signaling. Consistent with this, mir-279/996 knockouts are strongly enhanced by Notch heterozygosity, and activated nuclear Notch is impaired in the miRNA mutant. Although Hairless (H) is the canonical nuclear Notch pathway inhibitor, and H heterozygotes exhibit bristle cell fate phenotypes reflecting gain-of-Notch signaling, H/+ does not rescue mir-279/996 mutants. Instead, we identify Insensible (Insb), another neural nuclear Notch pathway inhibitor, as a critical direct miR-279/996 target. Insb is posttranscriptionally restricted to neurons by these miRNAs, and its heterozygosity strongly suppresses ectopic peripheral nervous system neurons in mir-279/996 mutants. Thus, proper assembly of multicellular mechanosensory organs requires a double-negative circuit involving miRNA-mediated suppression of a Notch repressor to assign non-neuronal cell fate.
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Affiliation(s)
| | - Hong Duan
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY
| | - Rajaguru Aradhya
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY
| | - Luis F de Navas
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY
| | - Brian Joseph
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY.,Gerstner Sloan-Kettering Graduate Program of Biomedical Sciences, New York, NY
| | - Boris Shklyar
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY
| | - Eric C Lai
- Department of Developmental Biology, Sloan-Kettering Institute, New York, NY .,Gerstner Sloan-Kettering Graduate Program of Biomedical Sciences, New York, NY
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29
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Abstract
Neurons allocated to sense organs respond rapidly to mechanical signals dictating behavioral responses at the organism level. The receptors that transduce these signals, and underlie these senses, are mechanically gated channels. Research on mechanosensation over the past decade, employing in many cases Drosophila as a model, has focused in typifying these receptors and in exploring the different ways, depending on context, in which these mechanosensors are modulated. In this review, we discuss first what we have learned from Drosophila on these mechanisms and we describe the different mechanosensory organs present in the Drosophila larvae and adult. Secondly, we focus on the progress obtained by studying the fly on the characterization of the mechanosensory crosstalk underlying complex behaviors like motor coordination. Finally, turning to a cellular level, we summarize what is known on the mechanical properties and sensing capabilities of neural cells and how they may affect neural physiology and pathology.
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Affiliation(s)
- Katerina Karkali
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.
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30
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Vuong-Brender TTK, Suman SK, Labouesse M. The apical ECM preserves embryonic integrity and distributes mechanical stress during morphogenesis. Development 2017; 144:4336-4349. [PMID: 28526752 PMCID: PMC5769628 DOI: 10.1242/dev.150383] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/11/2017] [Indexed: 12/14/2022]
Abstract
Epithelia are bound by both basal and apical extracellular matrices (ECM). Although the composition and function of the former have been intensively investigated, less is known about the latter. The embryonic sheath, the ECM apical to the Caenorhabditis elegans embryonic epidermis, has been suggested to promote elongation of the embryo. In an RNAi screen for the components of the sheath, we identified the zona pellucida domain proteins NOAH-1 and NOAH-2. We found that these proteins act in the same pathway, and in parallel to three other putative sheath proteins, the leucine-rich repeat proteins SYM-1, LET-4 and FBN-1/Fibrillin, to ensure embryonic integrity and promote elongation. Laser nano-ablation experiments to map the stress field show that NOAH-1 and NOAH-2, together with PAK-1/p21-activated kinase, maintain and relay the actomyosin-dependent stress generated within the lateral epidermis before muscles become active. Subsequently, loss-of-function experiments show that apical ECM proteins are essential for muscle anchoring and for relaying the mechanical input from muscle contractions, which are essential for elongation. Hence, the apical ECM contributes to morphogenesis by maintaining embryonic integrity and relaying mechanical stress. Summary: In C. elegans, embryonic apical extracellular matrix acts as a protective layer, a rigid anchor for muscle function and transmit actomyosin forces to promote embryonic elongation.
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Affiliation(s)
- Thanh Thi Kim Vuong-Brender
- Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire de Biologie du Développement - Institut de Biologie Paris Seine (LBD - IBPS), Paris 75005, France .,Development and Stem Cells Program, IGBMC, CNRS (UMR7104), INSERM (U964), Université de Strasbourg, 1 rue Laurent Fries, BP10142, Illkirch 67400, France
| | - Shashi Kumar Suman
- Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire de Biologie du Développement - Institut de Biologie Paris Seine (LBD - IBPS), Paris 75005, France.,Development and Stem Cells Program, IGBMC, CNRS (UMR7104), INSERM (U964), Université de Strasbourg, 1 rue Laurent Fries, BP10142, Illkirch 67400, France
| | - Michel Labouesse
- Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire de Biologie du Développement - Institut de Biologie Paris Seine (LBD - IBPS), Paris 75005, France .,Development and Stem Cells Program, IGBMC, CNRS (UMR7104), INSERM (U964), Université de Strasbourg, 1 rue Laurent Fries, BP10142, Illkirch 67400, France
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31
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Larter NK, Sun JS, Carlson JR. Organization and function of Drosophila odorant binding proteins. eLife 2016; 5. [PMID: 27845621 PMCID: PMC5127637 DOI: 10.7554/elife.20242] [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: 08/02/2016] [Accepted: 11/14/2016] [Indexed: 01/03/2023] Open
Abstract
Odorant binding proteins (Obps) are remarkable in their number, diversity, and abundance, yet their role in olfactory coding remains unclear. They are widely believed to be required for transporting hydrophobic odorants through an aqueous lymph to odorant receptors. We construct a map of the Drosophila antenna, in which the abundant Obps are mapped to olfactory sensilla with defined functions. The results lay a foundation for an incisive analysis of Obp function. The map identifies a sensillum type that contains a single abundant Obp, Obp28a. Surprisingly, deletion of the sole abundant Obp in these sensilla does not reduce the magnitude of their olfactory responses. The results suggest that this Obp is not required for odorant transport and that this sensillum does not require an abundant Obp. The results further suggest a novel role for this Obp in buffering changes in the odor environment, perhaps providing a molecular form of gain control. DOI:http://dx.doi.org/10.7554/eLife.20242.001 Insects use their sense of smell to find mates, to find food and – in the case of insects that transmit diseases such as malaria and Zika – to find us. If we can understand how insect scent detection works at the molecular and cellular level, we may be able to devise new ways of manipulating the insects’ sense of smell and prevent them from finding us. Insects contain a family of proteins called odorant binding proteins that are intriguing in several ways. They are numerous (there are 52 kinds in the fruit fly Drosophila), they are diverse and some are made in remarkably large amounts in the antennae. Fine hair-like structures known as olfactory sensilla protrude from the surface of the antennae. Odorant binding proteins are widely believed to carry odorant molecules through the fluid inside the sensilla to olfactory neurons, which then send signals that trigger the insect’s response to the scent. Larter et al. have now mapped the most abundant odorant binding proteins to the various olfactory sensilla of Drosophila. This revealed that a type of sensillum known as ab8 contained only one abundant odorant binding protein, called Obp28a. Unexpectedly, Larter et al. found that ab8 sensilla that are deprived of this protein respond strongly to odorant molecules. This result suggests that Obp28a is not required to transport odorants to the neurons in ab8; indeed, it appears that these neurons do not require an abundant odorant binding protein in order to respond to a scent. Instead, Obp28a helps to moderate the effects of sudden changes in the level of an odorant in the environment, so that concentrated odors do not trigger too large a response from the olfactory neurons. The details of the role that Obp28a plays in olfactory sensilla remain to be investigated in future studies, and the map created by Larter et al. also lays a foundation for studying the roles of other odorant binding proteins. The discovery that Obp28a is not needed to transport odorant molecules also raises questions about how insects are able to detect smells. Many odorant molecules repel water, so how do these molecules travel through the fluid in the sensilla if odorant binding proteins are not needed to transport them? DOI:http://dx.doi.org/10.7554/eLife.20242.002
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Affiliation(s)
- Nikki K Larter
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States.,Interdepartmental Neuroscience Program, Yale University, New Haven, United States
| | - Jennifer S Sun
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States
| | - John R Carlson
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States.,Interdepartmental Neuroscience Program, Yale University, New Haven, United States
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32
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Mechanosensory neurons control sweet sensing in Drosophila. Nat Commun 2016; 7:12872. [PMID: 27641708 PMCID: PMC5031804 DOI: 10.1038/ncomms12872] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 08/10/2016] [Indexed: 01/31/2023] Open
Abstract
Animals discriminate nutritious food from toxic substances using their sense of taste. Since taste perception requires taste receptor cells to come into contact with water-soluble chemicals, it is a form of contact chemosensation. Concurrent with that contact, mechanosensitive cells detect the texture of food and also contribute to the regulation of feeding. Little is known, however, about the extent to which chemosensitive and mechanosensitive circuits interact. Here, we show Drosophila prefers soft food at the expense of sweetness and that this preference requires labellar mechanosensory neurons (MNs) and the mechanosensory channel Nanchung. Activation of these labellar MNs causes GABAergic inhibition of sweet-sensing gustatory receptor neurons, reducing the perceived intensity of a sweet stimulus. These findings expand our understanding of the ways different sensory modalities cooperate to shape animal behaviour. How different sensory modalities interact to control feeding is poorly understood. Here, authors show that in Drosophila, activation of labellar mechanosensory neurons causes inhibition of sweet-sensing gustatory receptor neurons, as a result, Drosophila prefer soft food at the expense of sweetness.
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33
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Pratt MB, Titlow JS, Davis I, Barker AR, Dawe HR, Raff JW, Roque H. Drosophila sensory cilia lacking MKS proteins exhibit striking defects in development but only subtle defects in adults. J Cell Sci 2016; 129:3732-3743. [PMID: 27577095 PMCID: PMC5087661 DOI: 10.1242/jcs.194621] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/19/2016] [Indexed: 01/05/2023] Open
Abstract
Cilia are conserved organelles that have important motility, sensory and signalling roles. The transition zone (TZ) at the base of the cilium is crucial for cilia function, and defects in several TZ proteins are associated with human congenital ciliopathies such as nephronophthisis (NPHP) and Meckel-Gruber syndrome (MKS). In several species, MKS and NPHP proteins form separate complexes that cooperate with Cep290 to assemble the TZ, but flies seem to lack core components of the NPHP module. We show that MKS proteins in flies are spatially separated from Cep290 at the TZ, and that flies mutant for individual MKS genes fail to recruit other MKS proteins to the TZ, whereas Cep290 seems to be recruited normally. Although there are abnormalities in microtubule and membrane organisation in developing MKS mutant cilia, these defects are less apparent in adults, where sensory cilia and sperm flagella seem to function quite normally. Thus, localising MKS proteins to the cilium or flagellum is not essential for viability or fertility in flies.
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Affiliation(s)
- Metta B Pratt
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Joshua S Titlow
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Amy R Barker
- Centre for Microvascular Research, William Harvey Research Institute, Queen Mary University of London, London EC1M 6BQ, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Jordan W Raff
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Helio Roque
- The Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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34
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Gill HK, Cohen JD, Ayala-Figueroa J, Forman-Rubinsky R, Poggioli C, Bickard K, Parry JM, Pu P, Hall DH, Sundaram MV. Integrity of Narrow Epithelial Tubes in the C. elegans Excretory System Requires a Transient Luminal Matrix. PLoS Genet 2016; 12:e1006205. [PMID: 27482894 PMCID: PMC4970718 DOI: 10.1371/journal.pgen.1006205] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/28/2016] [Indexed: 02/07/2023] Open
Abstract
Most epithelial cells secrete a glycoprotein-rich apical extracellular matrix that can have diverse but still poorly understood roles in development and physiology. Zona Pellucida (ZP) domain glycoproteins are common constituents of these matrices, and their loss in humans is associated with a number of diseases. Understanding of the functions, organization and regulation of apical matrices has been hampered by difficulties in imaging them both in vivo and ex vivo. We identified the PAN-Apple, mucin and ZP domain glycoprotein LET-653 as an early and transient apical matrix component that shapes developing epithelia in C. elegans. LET-653 has modest effects on shaping of the vulva and epidermis, but is essential to prevent lumen fragmentation in the very narrow, unicellular excretory duct tube. We were able to image the transient LET-653 matrix by both live confocal imaging and transmission electron microscopy. Structure/function and fluorescence recovery after photobleaching studies revealed that LET-653 exists in two separate luminal matrix pools, a loose fibrillar matrix in the central core of the lumen, to which it binds dynamically via its PAN domains, and an apical-membrane-associated matrix, to which it binds stably via its ZP domain. The PAN domains are both necessary and sufficient to confer a cyclic pattern of duct lumen localization that precedes each molt, while the ZP domain is required for lumen integrity. Ectopic expression of full-length LET-653, but not the PAN domains alone, could expand lumen diameter in the developing gut tube, where LET-653 is not normally expressed. Together, these data support a model in which the PAN domains regulate the ability of the LET-653 ZP domain to interact with other factors at the apical membrane, and this ZP domain interaction promotes expansion and maintenance of lumen diameter. These data identify a transient apical matrix component present prior to cuticle secretion in C. elegans, demonstrate critical roles for this matrix component in supporting lumen integrity within narrow bore tubes such as those found in the mammalian microvasculature, and reveal functional importance of the evolutionarily conserved ZP domain in this tube protecting activity. Most organs in the body are made up of networks of tubes that transport fluids or gases. These tubes come in many different sizes and shapes, with some narrow capillaries being only one cell in diameter. As tubes develop and take their final shapes, they secrete various glycoproteins into their hollow interior or lumen. The functions of these luminal proteins are not well understood, but there is increasing evidence that they are important for lumen shaping and that their loss can contribute to diseases such as cardiovascular disease and chronic kidney disease. Through studies of the nematode C. elegans, we identified a luminal glycoprotein, LET-653, that is transiently expressed in multiple developing tube types but is particularly critical to maintain integrity of the narrowest, unicellular tubes. We identified protein domains that direct LET-653 to specific apical matrix compartments and mediate its oscillatory pattern of lumen localization. Furthermore, we showed that the LET-653 tube-protecting activity depends on a Zona Pellucida (ZP) domain similar to that found in the mammalian egg-coat and in many other luminal or sensory matrix proteins involved in human disease.
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Affiliation(s)
- Hasreet K. Gill
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jennifer D. Cohen
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jesus Ayala-Figueroa
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Rachel Forman-Rubinsky
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Corey Poggioli
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Kevin Bickard
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jean M. Parry
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Biology, Georgian Court University, Lakewood, New Jersey, United States of America
| | - Pu Pu
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - David H. Hall
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Meera V. Sundaram
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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35
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Li T, Giagtzoglou N, Eberl DF, Jaiswal SN, Cai T, Godt D, Groves AK, Bellen HJ. The E3 ligase Ubr3 regulates Usher syndrome and MYH9 disorder proteins in the auditory organs of Drosophila and mammals. eLife 2016; 5. [PMID: 27331610 PMCID: PMC4978524 DOI: 10.7554/elife.15258] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 06/21/2016] [Indexed: 01/08/2023] Open
Abstract
Myosins play essential roles in the development and function of auditory organs and multiple myosin genes are associated with hereditary forms of deafness. Using a forward genetic screen in Drosophila, we identified an E3 ligase, Ubr3, as an essential gene for auditory organ development. Ubr3 negatively regulates the mono-ubiquitination of non-muscle Myosin II, a protein associated with hearing loss in humans. The mono-ubiquitination of Myosin II promotes its physical interaction with Myosin VIIa, a protein responsible for Usher syndrome type IB. We show that ubr3 mutants phenocopy pathogenic variants of Myosin II and that Ubr3 interacts genetically and physically with three Usher syndrome proteins. The interactions between Myosin VIIa and Myosin IIa are conserved in the mammalian cochlea and in human retinal pigment epithelium cells. Our work reveals a novel mechanism that regulates protein complexes affected in two forms of syndromic deafness and suggests a molecular function for Myosin IIa in auditory organs.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Nikolaos Giagtzoglou
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neurology, Baylor College of Medicine, Houston, United States
| | - Daniel F Eberl
- Department of Biology, University of Iowa, Iowa City, United States
| | - Sonal Nagarkar Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Tiantian Cai
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Dorothea Godt
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, United States
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36
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Sobala LF, Adler PN. The Gene Expression Program for the Formation of Wing Cuticle in Drosophila. PLoS Genet 2016; 12:e1006100. [PMID: 27232182 PMCID: PMC4883753 DOI: 10.1371/journal.pgen.1006100] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/11/2016] [Indexed: 11/19/2022] Open
Abstract
The cuticular exoskeleton of insects and other arthropods is a remarkably versatile material with a complex multilayer structure. We made use of the ability to isolate cuticle synthesizing cells in relatively pure form by dissecting pupal wings and we used RNAseq to identify genes expressed during the formation of the adult wing cuticle. We observed dramatic changes in gene expression during cuticle deposition, and combined with transmission electron microscopy, we were able to identify candidate genes for the deposition of the different cuticular layers. Among genes of interest that dramatically change their expression during the cuticle deposition program are ones that encode cuticle proteins, ZP domain proteins, cuticle modifying proteins and transcription factors, as well as genes of unknown function. A striking finding is that mutations in a number of genes that are expressed almost exclusively during the deposition of the envelope (the thin outermost layer that is deposited first) result in gross defects in the procuticle (the thick chitinous layer that is deposited last). An attractive hypothesis to explain this is that the deposition of the different cuticle layers is not independent with the envelope instructing the formation of later layers. Alternatively, some of the genes expressed during the deposition of the envelope could form a platform that is essential for the deposition of all cuticle layers. Insects and other arthropods are an extremely successful group of animals. A unique and key feature of their lifestyle is their chitin containing cuticular exoskeleton, a complex layered material, which remains rather poorly understood for so prominent of a biological material. We have characterized the gene expression pattern of wing epithelial cells over the period of cuticle formation and also carried out transmission electron microscopy, which allows us to identify genes that likely play a role in the formation of different cuticle layers. Functional studies suggest that the deposition of the earliest layer influences the deposition of the later ones.
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Affiliation(s)
- Lukasz F. Sobala
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, Virginia, United States of America
| | - Paul N. Adler
- Biology Department and Cell Biology Department, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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37
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38
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Abstract
In mechanotransduction, sensory receptors convert force into electrical signals to mediate such diverse functions as touch, pain, and hearing. In this issue of Cell, Zhang et al. present evidence that the fly NompC channel senses mechanical stimuli using its N-terminal tail as a tether between the cell membrane and microtubules.
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Affiliation(s)
- Zachary A Knecht
- National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02458, USA; Volen Center for Complex Systems, Department of Biology, Brandeis University, Waltham, MA 02458, USA
| | - Rachelle Gaudet
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Paul A Garrity
- National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02458, USA; Volen Center for Complex Systems, Department of Biology, Brandeis University, Waltham, MA 02458, USA.
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39
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Ankyrin Repeats Convey Force to Gate the NOMPC Mechanotransduction Channel. Cell 2015; 162:1391-403. [PMID: 26359990 DOI: 10.1016/j.cell.2015.08.024] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/26/2015] [Accepted: 07/13/2015] [Indexed: 12/11/2022]
Abstract
How metazoan mechanotransduction channels sense mechanical stimuli is not well understood. The NOMPC channel in the transient receptor potential (TRP) family, a mechanotransduction channel for Drosophila touch sensation and hearing, contains 29 Ankyrin repeats (ARs) that associate with microtubules. These ARs have been postulated to act as a tether that conveys force to the channel. Here, we report that these N-terminal ARs form a cytoplasmic domain essential for NOMPC mechanogating in vitro, mechanosensitivity of touch receptor neurons in vivo, and touch-induced behaviors of Drosophila larvae. Duplicating the ARs elongates the filaments that tether NOMPC to microtubules in mechanosensory neurons. Moreover, microtubule association is required for NOMPC mechanogating. Importantly, transferring the NOMPC ARs to mechanoinsensitive voltage-gated potassium channels confers mechanosensitivity to the chimeric channels. These experiments strongly support a tether mechanism of mechanogating for the NOMPC channel, providing insights into the basis of mechanosensitivity of mechanotransduction channels.
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40
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Abstract
Insect hearing has independently evolved multiple times in the context of intraspecific communication and predator detection by transforming proprioceptive organs into ears. Research over the past decade, ranging from the biophysics of sound reception to molecular aspects of auditory transduction to the neuronal mechanisms of auditory signal processing, has greatly advanced our understanding of how insects hear. Apart from evolutionary innovations that seem unique to insect hearing, parallels between insect and vertebrate auditory systems have been uncovered, and the auditory sensory cells of insects and vertebrates turned out to be evolutionarily related. This review summarizes our current understanding of insect hearing. It also discusses recent advances in insect auditory research, which have put forward insect auditory systems for studying biological aspects that extend beyond hearing, such as cilium function, neuronal signal computation, and sensory system evolution.
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Affiliation(s)
- Martin C Göpfert
- Department of Cellular Neurobiology, University of Göttingen, D-37077 Göttingen, Germany;
| | - R Matthias Hennig
- Department of Biology, Behavioral Physiology, Humboldt-Universität zu Berlin, D-10115 Berlin, Germany;
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41
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Drosophila Ionotropic Receptor 25a mediates circadian clock resetting by temperature. Nature 2015; 527:516-20. [PMID: 26580016 DOI: 10.1038/nature16148] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 10/26/2015] [Indexed: 12/27/2022]
Abstract
Circadian clocks are endogenous timers adjusting behaviour and physiology with the solar day. Synchronized circadian clocks improve fitness and are crucial for our physical and mental well-being. Visual and non-visual photoreceptors are responsible for synchronizing circadian clocks to light, but clock-resetting is also achieved by alternating day and night temperatures with only 2-4 °C difference. This temperature sensitivity is remarkable considering that the circadian clock period (~24 h) is largely independent of surrounding ambient temperatures. Here we show that Drosophila Ionotropic Receptor 25a (IR25a) is required for behavioural synchronization to low-amplitude temperature cycles. This channel is expressed in sensory neurons of internal stretch receptors previously implicated in temperature synchronization of the circadian clock. IR25a is required for temperature-synchronized clock protein oscillations in subsets of central clock neurons. Extracellular leg nerve recordings reveal temperature- and IR25a-dependent sensory responses, and IR25a misexpression confers temperature-dependent firing of heterologous neurons. We propose that IR25a is part of an input pathway to the circadian clock that detects small temperature differences. This pathway operates in the absence of known 'hot' and 'cold' sensors in the Drosophila antenna, revealing the existence of novel periphery-to-brain temperature signalling channels.
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Ray RP, Matamoro-Vidal A, Ribeiro PS, Tapon N, Houle D, Salazar-Ciudad I, Thompson BJ. Patterned Anchorage to the Apical Extracellular Matrix Defines Tissue Shape in the Developing Appendages of Drosophila. Dev Cell 2015; 34:310-22. [PMID: 26190146 PMCID: PMC4539345 DOI: 10.1016/j.devcel.2015.06.019] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 04/02/2015] [Accepted: 06/19/2015] [Indexed: 11/26/2022]
Abstract
How tissues acquire their characteristic shape is a fundamental unresolved question in biology. While genes have been characterized that control local mechanical forces to elongate epithelial tissues, genes controlling global forces in epithelia have yet to be identified. Here, we describe a genetic pathway that shapes appendages in Drosophila by defining the pattern of global tensile forces in the tissue. In the appendages, shape arises from tension generated by cell constriction and localized anchorage of the epithelium to the cuticle via the apical extracellular-matrix protein Dumpy (Dp). Altering Dp expression in the developing wing results in predictable changes in wing shape that can be simulated by a computational model that incorporates only tissue contraction and localized anchorage. Three other wing shape genes, narrow, tapered, and lanceolate, encode components of a pathway that modulates Dp distribution in the wing to refine the global force pattern and thus wing shape.
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Affiliation(s)
- Robert P Ray
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK; The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
| | - Alexis Matamoro-Vidal
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA; Department de Genètica i Microbiologia, Genomics, Bioinformatics, and Evolution Group, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Paulo S Ribeiro
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK; Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Nic Tapon
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
| | - David Houle
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Isaac Salazar-Ciudad
- Department de Genètica i Microbiologia, Genomics, Bioinformatics, and Evolution Group, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain; Center of Excellence in Experimental and Computational Developmental Biology, Developmental Biology Program, Institute of Biotechnology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
| | - Barry J Thompson
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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Drosophila Hook-Related Protein (Girdin) Is Essential for Sensory Dendrite Formation. Genetics 2015; 200:1149-59. [PMID: 26058848 DOI: 10.1534/genetics.115.178954] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/05/2015] [Indexed: 01/22/2023] Open
Abstract
The dendrite of the sensory neuron is surrounded by support cells and is composed of two specialized compartments: the inner segment and the sensory cilium. How the sensory dendrite is formed and maintained is not well understood. Hook-related proteins (HkRP) like Girdin, DAPLE, and Gipie are actin-binding proteins, implicated in actin organization and in cell motility. Here, we show that the Drosophila melanogaster single member of the Hook-related protein family, Girdin, is essential for sensory dendrite formation and function. Mutations in girdin were identified during a screen for fly mutants with no mechanosensory function. Physiological, morphological, and ultrastructural studies of girdin mutant flies indicate that the mechanosensory neurons innervating external sensory organs (bristles) initially form a ciliated dendrite that degenerates shortly after, followed by the clustering of their cell bodies. Importantly, we observed that Girdin is expressed transiently during dendrite morphogenesis in three previously unidentified actin-based structures surrounding the inner segment tip and the sensory cilium. These actin structures are largely missing in girdin mutant. Defects in cilia are observed in other sensory organs such as those mediating olfaction and taste, suggesting that Girdin has a general role in forming sensory dendrites in Drosophila. These suggest that Girdin functions temporarily within the sensory organ and that this function is essential for the formation of the sensory dendrites via actin structures.
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Coordination and fine motor control depend on Drosophila TRPγ. Nat Commun 2015; 6:7288. [PMID: 26028119 DOI: 10.1038/ncomms8288] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 04/26/2015] [Indexed: 12/31/2022] Open
Abstract
Motor coordination is broadly divided into gross and fine motor control, both of which depend on proprioceptive organs. However, the channels that function specifically in fine motor control are unknown. Here we show that mutations in trpγ disrupt fine motor control while leaving gross motor proficiency intact. The mutants are unable to coordinate precise leg movements during walking, and are ineffective in traversing large gaps due to an inability in making subtle postural adaptations that are requisite for this task. TRPγ is expressed in proprioceptive organs, and is required in both neurons and glia for gap crossing. We expressed TRPγ in vitro, and found that its activity is promoted by membrane stretch. A mutation eliminating the Na(+)/Ca(2+) exchanger suppresses the gap-crossing phenotype of trpγ flies. Our findings indicate that TRPγ contributes to fine motor control through mechanical activation in proprioceptive organs, thereby promoting Ca(2+) influx, which is required for function.
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Kachalo S, Naveed H, Cao Y, Zhao J, Liang J. Mechanical model of geometric cell and topological algorithm for cell dynamics from single-cell to formation of monolayered tissues with pattern. PLoS One 2015; 10:e0126484. [PMID: 25974182 PMCID: PMC4431879 DOI: 10.1371/journal.pone.0126484] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 04/02/2015] [Indexed: 11/19/2022] Open
Abstract
Geometric and mechanical properties of individual cells and interactions among neighboring cells are the basis of formation of tissue patterns. Understanding the complex interplay of cells is essential for gaining insight into embryogenesis, tissue development, and other emerging behavior. Here we describe a cell model and an efficient geometric algorithm for studying the dynamic process of tissue formation in 2D (e.g. epithelial tissues). Our approach improves upon previous methods by incorporating properties of individual cells as well as detailed description of the dynamic growth process, with all topological changes accounted for. Cell size, shape, and division plane orientation are modeled realistically. In addition, cell birth, cell growth, cell shrinkage, cell death, cell division, cell collision, and cell rearrangements are now fully accounted for. Different models of cell-cell interactions, such as lateral inhibition during the process of growth, can be studied in detail. Cellular pattern formation for monolayered tissues from arbitrary initial conditions, including that of a single cell, can also be studied in detail. Computational efficiency is achieved through the employment of a special data structure that ensures access to neighboring cells in constant time, without additional space requirement. We have successfully generated tissues consisting of more than 20,000 cells starting from 2 cells within 1 hour. We show that our model can be used to study embryogenesis, tissue fusion, and cell apoptosis. We give detailed study of the classical developmental process of bristle formation on the epidermis of D. melanogaster and the fundamental problem of homeostatic size control in epithelial tissues. Simulation results reveal significant roles of solubility of secreted factors in both the bristle formation and the homeostatic control of tissue size. Our method can be used to study broad problems in monolayered tissue formation. Our software is publicly available.
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Affiliation(s)
- Sëma Kachalo
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, 60607
| | - Hammad Naveed
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, 60607
- Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Youfang Cao
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, 60607
| | - Jieling Zhao
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, 60607
| | - Jie Liang
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, 60607
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The Adhesion GPCR Latrophilin/CIRL Shapes Mechanosensation. Cell Rep 2015; 11:866-874. [DOI: 10.1016/j.celrep.2015.04.008] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 03/09/2015] [Accepted: 04/01/2015] [Indexed: 01/09/2023] Open
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Abstract
Drosophila melanogaster is a powerful genetic model organism to understand the function of proteins in specific cellular processes. Cilia have been extensively studied in Drosophila playing various sensory functions that are essential for fly survival. Indeed, flies defective in cilia formation cannot walk, fly, or feed properly. Drosophila harbors different types of cilia that can be motile or immotile or that can show compartimentalized (intraflagellar transport (IFT)-dependent) or cytoplasmic (IFT-independent) mode of assembly. Therefore, Drosophila represents an advantageous model organism to study the function of novel ciliary candidates and to address specific questions such as their requirement for IFT-dependent processes versus other aspects of cilia-associated functions. This chapter describes protocols to visualize cilia by direct or indirect fluorescent labeling and protocols to analyze ciliary ultrastructure by electron microscopy.
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Casadio A, Longman D, Hug N, Delavaine L, Vallejos Baier R, Alonso CR, Cáceres JF. Identification and characterization of novel factors that act in the nonsense-mediated mRNA decay pathway in nematodes, flies and mammals. EMBO Rep 2014; 16:71-8. [PMID: 25452588 PMCID: PMC4304730 DOI: 10.15252/embr.201439183] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a surveillance mechanism that degrades mRNAs harboring premature termination codons (PTCs). We have conducted a genome-wide RNAi screen in Caenorhabditis elegans that resulted in the identification of five novel NMD genes that are conserved throughout evolution. Two of their human homologs, GNL2 (ngp-1) and SEC13 (npp-20), are also required for NMD in human cells. We also show that the C. elegans gene noah-2, which is present in Drosophila melanogaster but absent in humans, is an NMD factor in fruit flies. Altogether, these data identify novel NMD factors that are conserved throughout evolution, highlighting the complexity of the NMD pathway and suggesting that yet uncovered novel factors may act to regulate this process.
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Affiliation(s)
- Angela Casadio
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital University of Edinburgh, Edinburgh, UK
| | - Dasa Longman
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital University of Edinburgh, Edinburgh, UK
| | - Nele Hug
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital University of Edinburgh, Edinburgh, UK
| | - Laurent Delavaine
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital University of Edinburgh, Edinburgh, UK
| | | | | | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Western General Hospital University of Edinburgh, Edinburgh, UK
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Bokolia NP, Mishra M. Hearing molecules, mechanism and transportation: modeled in Drosophila melanogaster. Dev Neurobiol 2014; 75:109-30. [PMID: 25081222 DOI: 10.1002/dneu.22221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/29/2014] [Accepted: 07/29/2014] [Indexed: 01/19/2023]
Abstract
Mechanosensory transduction underlies the perception of touch, sound and acceleration. The mechanical signals exist in the environment are resensed by the specialized mechanosensory cells, which convert the external forces into the electrical signals. Hearing is a magnificent example that relies on the mechanotransduction mediated by the auditory cells, for example the inner-ear hair cells in vertebrates and the Johnston's organ (JO) in fly. Previous studies have shown the fundamental physiological processes in the fly and vertebrate auditory organs are similar, suggesting that there might be a set of similar molecules underlying these processes. The molecular studies of the fly JO have been shown to be remarkably successful in discovering the developmental and functional genes that provided further implications in vertebrates. Several evolutionarily conserved molecules and signaling pathways have been shown to govern the development of the auditory organs in both vertebrates and invertebrates. The current review describes the similarities and differences between the vertebrate and fly auditory organs at developmental, structural, molecular, and transportation levels.
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Affiliation(s)
- Naveen Prakash Bokolia
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Orissa, India
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The extracellular matrix protein artichoke is required for integrity of ciliated mechanosensory and chemosensory organs in Drosophila embryos. Genetics 2014; 196:1091-102. [PMID: 24496014 DOI: 10.1534/genetics.113.156323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sensory cilia are often encapsulated by an extracellular matrix (ECM). In Caenorhabditis elegans, Drosophila melanogaster, and vertebrates, this ECM is thought to be directly involved in ciliary mechanosensing by coupling external forces to the ciliary membrane. Drosophila mechano- and chemosensory cilia are both associated with an ECM, indicating that the ECM may have additional roles that go beyond mechanosensory cilium function. Here, we identify Artichoke (ATK), an evolutionarily conserved leucine-rich repeat ECM protein that is required for normal morphogenesis and function of ciliated sensilla in Drosophila. atk is transiently expressed in accessory cells in all ciliated sensory organs during their late embryonic development. Antibody stainings show ATK protein in the ECM that surrounds sensory cilia. Loss of ATK protein in atk null mutants leads to cilium deformation and disorientation in chordotonal organs, apparently without uncoupling the cilia from the ECM, and consequently to locomotion defects. Moreover, impaired chemotaxis in atk mutant larvae suggests that, based on ATK protein localization, the ECM is also crucial for the correct assembly of chemosensory receptors. In addition to defining a novel ECM component, our findings show the importance of ECM integrity for the proper morphogenesis of ciliated organs in different sensory modalities.
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