151
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Serotonergic modulation of visual neurons in Drosophila melanogaster. PLoS Genet 2020; 16:e1009003. [PMID: 32866139 PMCID: PMC7485980 DOI: 10.1371/journal.pgen.1009003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 09/11/2020] [Accepted: 07/22/2020] [Indexed: 02/06/2023] Open
Abstract
Sensory systems rely on neuromodulators, such as serotonin, to provide flexibility for information processing as stimuli vary, such as light intensity throughout the day. Serotonergic neurons broadly innervate the optic ganglia of Drosophila melanogaster, a widely used model for studying vision. It remains unclear whether serotonin modulates the physiology of interneurons in the optic ganglia. To address this question, we first mapped the expression patterns of serotonin receptors in the visual system, focusing on a subset of cells with processes in the first optic ganglion, the lamina. Serotonin receptor expression was found in several types of columnar cells in the lamina including 5-HT2B in lamina monopolar cell L2, required for spatiotemporal luminance contrast, and both 5-HT1A and 5-HT1B in T1 cells, whose function is unknown. Subcellular mapping with GFP-tagged 5-HT2B and 5-HT1A constructs indicated that these receptors localize to layer M2 of the medulla, proximal to serotonergic boutons, suggesting that the medulla neuropil is the primary site of serotonergic regulation for these neurons. Exogenous serotonin increased basal intracellular calcium in L2 terminals in layer M2 and modestly decreased the duration of visually induced calcium transients in L2 neurons following repeated dark flashes, but otherwise did not alter the calcium transients. Flies without functional 5-HT2B failed to show an increase in basal calcium in response to serotonin. 5-HT2B mutants also failed to show a change in amplitude in their response to repeated light flashes but other calcium transient parameters were relatively unaffected. While we did not detect serotonin receptor expression in L1 neurons, they, like L2, underwent serotonin-induced changes in basal calcium, presumably via interactions with other cells. These data demonstrate that serotonin modulates the physiology of interneurons involved in early visual processing in Drosophila. Serotonergic neurons innervate the Drosophila melanogaster eye, but it was not known whether serotonin signaling could induce acute physiological responses in visual interneurons. We found serotonin receptors expressed in all neuropils of the optic lobe and identified specific neurons involved in visual information processing that express serotonin receptors. Activation of these receptors increased intracellular calcium in first order interneurons L1 and L2 and may enhance visually induced calcium transients in L2 neurons. These data support a role for the serotonergic neuromodulation of interneurons in the Drosophila visual system.
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152
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Pridie C, Ueda K, Simmonds AJ. Rosy Beginnings: Studying Peroxisomes in Drosophila. Front Cell Dev Biol 2020; 8:835. [PMID: 32984330 PMCID: PMC7477296 DOI: 10.3389/fcell.2020.00835] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/04/2020] [Indexed: 12/19/2022] Open
Abstract
Research using the fruit fly Drosophila melanogaster has traditionally focused on understanding how mutations affecting gene regulation or function affect processes linked to animal development. Accordingly, flies have become an essential foundation of modern medical research through repeated contributions to our fundamental understanding of how their homologs of human genes function. Peroxisomes are organelles that metabolize lipids and reactive oxygen species like peroxides. However, despite clear linkage of mutations in human genes affecting peroxisomes to developmental defects, for many years fly models were conspicuously absent from the study of peroxisomes. Now, the few early studies linking the Rosy eye color phenotype to peroxisomes in flies have been joined by a growing body of research establishing novel roles for peroxisomes during the development or function of specific tissues or cell types. Similarly, unique properties of cultured fly Schneider 2 cells have advanced our understanding of how peroxisomes move on the cytoskeleton. Here, we profile how those past and more recent Drosophila studies started to link specific effects of peroxisome dysfunction to organ development and highlight the utility of flies as a model for human peroxisomal diseases. We also identify key differences in the function and proliferation of fly peroxisomes compared to yeast or mammals. Finally, we discuss the future of the fly model system for peroxisome research including new techniques that should support identification of additional tissue specific regulation of and roles for peroxisomes.
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Affiliation(s)
- C Pridie
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Kazuki Ueda
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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153
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Zappia MP, de Castro L, Ariss MM, Jefferson H, Islam AB, Frolov MV. A cell atlas of adult muscle precursors uncovers early events in fibre-type divergence in Drosophila. EMBO Rep 2020; 21:e49555. [PMID: 32815271 PMCID: PMC7534622 DOI: 10.15252/embr.201949555] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 07/12/2020] [Accepted: 07/24/2020] [Indexed: 12/31/2022] Open
Abstract
In Drosophila, the wing disc‐associated muscle precursor cells give rise to the fibrillar indirect flight muscles (IFM) and the tubular direct flight muscles (DFM). To understand early transcriptional events underlying this muscle diversification, we performed single‐cell RNA‐sequencing experiments and built a cell atlas of myoblasts associated with third instar larval wing disc. Our analysis identified distinct transcriptional signatures for IFM and DFM myoblasts that underlie the molecular basis of their divergence. The atlas further revealed various states of differentiation of myoblasts, thus illustrating previously unappreciated spatial and temporal heterogeneity among them. We identified and validated novel markers for both IFM and DFM myoblasts at various states of differentiation by immunofluorescence and genetic cell‐tracing experiments. Finally, we performed a systematic genetic screen using a panel of markers from the reference cell atlas as an entry point and found a novel gene, Amalgam which is functionally important in muscle development. Our work provides a framework for leveraging scRNA‐seq for gene discovery and details a strategy that can be applied to other scRNA‐seq datasets.
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Affiliation(s)
- Maria Paula Zappia
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Lucia de Castro
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Majd M Ariss
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Holly Jefferson
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Abul Bmmk Islam
- Department of Genetic Engineering and Biotechnology, University of Dhaka, Dhaka, Bangladesh
| | - Maxim V Frolov
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL, USA
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154
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Different functions of two putative Drosophila α 2δ subunits in the same identified motoneurons. Sci Rep 2020; 10:13670. [PMID: 32792569 PMCID: PMC7426832 DOI: 10.1038/s41598-020-69748-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 07/15/2020] [Indexed: 11/24/2022] Open
Abstract
Voltage gated calcium channels (VGCCs) regulate neuronal excitability and translate activity into calcium dependent signaling. The α1 subunit of high voltage activated (HVA) VGCCs associates with α2δ accessory subunits, which may affect calcium channel biophysical properties, cell surface expression, localization and transport and are thus important players in calcium-dependent signaling. In vertebrates, the functions of the different combinations of the four α2δ and the seven HVA α1 subunits are incompletely understood, in particular with respect to partially redundant or separate functions in neurons. This study capitalizes on the relatively simpler situation in the Drosophila genetic model containing two neuronal putative α2δ subunits, straightjacket and CG4587, and one Cav1 and Cav2 homolog each, both with well-described functions in different compartments of identified motoneurons. Straightjacket is required for normal Cav1 and Cav2 current amplitudes and correct Cav2 channel function in all neuronal compartments. By contrast, CG4587 does not affect Cav1 or Cav2 current amplitudes or presynaptic function, but is required for correct Cav2 channel allocation to the axonal versus the dendritic domain. We suggest that the two different putative α2δ subunits are required in the same neurons to regulate different functions of VGCCs.
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155
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DeLuca SZ, Ghildiyal M, Pang LY, Spradling AC. Differentiating Drosophila female germ cells initiate Polycomb silencing by regulating PRC2-interacting proteins. eLife 2020; 9:e56922. [PMID: 32773039 PMCID: PMC7438113 DOI: 10.7554/elife.56922] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 08/06/2020] [Indexed: 01/18/2023] Open
Abstract
Polycomb silencing represses gene expression and provides a molecular memory of chromatin state that is essential for animal development. We show that Drosophila female germline stem cells (GSCs) provide a powerful system for studying Polycomb silencing. GSCs have a non-canonical distribution of PRC2 activity and lack silenced chromatin like embryonic progenitors. As GSC daughters differentiate into nurse cells and oocytes, nurse cells, like embryonic somatic cells, silence genes in traditional Polycomb domains and in generally inactive chromatin. Developmentally controlled expression of two Polycomb repressive complex 2 (PRC2)-interacting proteins, Pcl and Scm, initiate silencing during differentiation. In GSCs, abundant Pcl inhibits PRC2-dependent silencing globally, while in nurse cells Pcl declines and newly induced Scm concentrates PRC2 activity on traditional Polycomb domains. Our results suggest that PRC2-dependent silencing is developmentally regulated by accessory proteins that either increase the concentration of PRC2 at target sites or inhibit the rate that PRC2 samples chromatin.
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Affiliation(s)
- Steven Z DeLuca
- Howard Hughes Medical Institute Research Laboratories Department of Embryology, Carnegie Institution for ScienceBaltimoreUnited States
| | - Megha Ghildiyal
- Howard Hughes Medical Institute Research Laboratories Department of Embryology, Carnegie Institution for ScienceBaltimoreUnited States
| | - Liang-Yu Pang
- Howard Hughes Medical Institute Research Laboratories Department of Embryology, Carnegie Institution for ScienceBaltimoreUnited States
| | - Allan C Spradling
- Howard Hughes Medical Institute Research Laboratories Department of Embryology, Carnegie Institution for ScienceBaltimoreUnited States
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156
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Palladino J, Chavan A, Sposato A, Mason TD, Mellone BG. Targeted De Novo Centromere Formation in Drosophila Reveals Plasticity and Maintenance Potential of CENP-A Chromatin. Dev Cell 2020; 52:379-394.e7. [PMID: 32049040 DOI: 10.1016/j.devcel.2020.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/17/2019] [Accepted: 01/06/2020] [Indexed: 11/25/2022]
Abstract
Centromeres are essential for accurate chromosome segregation and are marked by centromere protein A (CENP-A) nucleosomes. Mis-targeted CENP-A chromatin has been shown to seed centromeres at non-centromeric DNA. However, the requirements for such de novo centromere formation and transmission in vivo remain unknown. Here, we employ Drosophila melanogaster and the LacI/lacO system to investigate the ability of targeted de novo centromeres to assemble and be inherited through development. De novo centromeres form efficiently at six distinct genomic locations, which include actively transcribed chromatin and heterochromatin, and cause widespread chromosomal instability. During tethering, de novo centromeres sometimes prevail, causing the loss of the endogenous centromere via DNA breaks and HP1-dependent epigenetic inactivation. Transient induction of de novo centromeres and chromosome healing in early embryogenesis show that, once established, these centromeres can be maintained through development. Our results underpin the ability of CENP-A chromatin to establish and sustain mitotic centromere function in Drosophila.
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Affiliation(s)
- Jason Palladino
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Ankita Chavan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Anthony Sposato
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Timothy D Mason
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Barbara G Mellone
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA.
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157
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Mariano V, Achsel T, Bagni C, Kanellopoulos AK. Modelling Learning and Memory in Drosophila to Understand Intellectual Disabilities. Neuroscience 2020; 445:12-30. [PMID: 32730949 DOI: 10.1016/j.neuroscience.2020.07.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 12/24/2022]
Abstract
Neurodevelopmental disorders (NDDs) include a large number of conditions such as Fragile X syndrome, autism spectrum disorders and Down syndrome, among others. They are characterized by limitations in adaptive and social behaviors, as well as intellectual disability (ID). Whole-exome and whole-genome sequencing studies have highlighted a large number of NDD/ID risk genes. To dissect the genetic causes and underlying biological pathways, in vivo experimental validation of the effects of these mutations is needed. The fruit fly, Drosophila melanogaster, is an ideal model to study NDDs, with highly tractable genetics, combined with simple behavioral and circuit assays, permitting rapid medium-throughput screening of NDD/ID risk genes. Here, we review studies where the use of well-established assays to study mechanisms of learning and memory in Drosophila has permitted insights into molecular mechanisms underlying IDs. We discuss how technologies in the fly model, combined with a high degree of molecular and physiological conservation between flies and mammals, highlight the Drosophila system as an ideal model to study neurodevelopmental disorders, from genetics to behavior.
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Affiliation(s)
- Vittoria Mariano
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland; Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Tilmann Achsel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne 1005, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome 00133, Italy.
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158
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Douris V, Denecke S, Van Leeuwen T, Bass C, Nauen R, Vontas J. Using CRISPR/Cas9 genome modification to understand the genetic basis of insecticide resistance: Drosophila and beyond. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 167:104595. [PMID: 32527434 DOI: 10.1016/j.pestbp.2020.104595] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
Chemical insecticides are a major tool for the control of many of the world's most damaging arthropod pests. However, their intensive application is often associated with the emergence of resistance, sometimes with serious implications for sustainable pest control. To mitigate failure of insecticide-based control tools, the mechanisms by which insects have evolved resistance must be elucidated. This includes both identification and functional characterization of putative resistance genes and/or mutations. Research on this topic has been greatly facilitated by using powerful genetic model insects like Drosophila melanogaster, and more recently by advances in genome modification technology, notably CRISPR/Cas9. Here, we present the advances that have been made through the application of genome modification technology in insecticide resistance research. The majority of the work conducted in the field to date has made use of genetic tools and resources available in D. melanogaster. This has greatly enhanced our understanding of resistance mechanisms, especially those mediated by insensitivity of the pesticide target-site. We discuss this progress for a series of different insecticide targets, but also report a number of unsuccessful or inconclusive attempts that highlight some inherent limitations of using Drosophila to characterize resistance mechanisms identified in arthropod pests. We also discuss an experimental framework that may circumvent current limitations while retaining the genetic versatility and robustness that Drosophila has to offer. Finally, we describe examples of direct CRISPR/Cas9 use in non-model pest species, an approach that will likely find much wider application in the near future.
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Affiliation(s)
- Vassilis Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13 Heraklion, Crete, Greece; Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece.
| | - Shane Denecke
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13 Heraklion, Crete, Greece
| | - Thomas Van Leeuwen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, UK
| | - Ralf Nauen
- Bayer AG, CropScience Division, R&D Pest Control, D-40789 Monheim, Germany
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, 700 13 Heraklion, Crete, Greece; Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, Greece.
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159
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Harris RE, Stinchfield MJ, Nystrom SL, McKay DJ, Hariharan IK. Damage-responsive, maturity-silenced enhancers regulate multiple genes that direct regeneration in Drosophila. eLife 2020; 9:58305. [PMID: 32490812 PMCID: PMC7299344 DOI: 10.7554/elife.58305] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/28/2020] [Indexed: 12/31/2022] Open
Abstract
Like tissues of many organisms, Drosophila imaginal discs lose the ability to regenerate as they mature. This loss of regenerative capacity coincides with reduced damage-responsive expression of multiple genes needed for regeneration. We previously showed that two such genes, wg and Wnt6, are regulated by a single damage-responsive enhancer that becomes progressively inactivated via Polycomb-mediated silencing as discs mature (Harris et al., 2016). Here we explore the generality of this mechanism and identify additional damage-responsive, maturity-silenced (DRMS) enhancers, some near genes known to be required for regeneration such as Mmp1, and others near genes that we now show function in regeneration. Using a novel GAL4-independent ablation system we characterize two DRMS-associated genes, apontic (apt), which curtails regeneration and CG9752/asperous (aspr), which promotes it. This mechanism of suppressing regeneration by silencing damage-responsive enhancers at multiple loci can be partially overcome by reducing activity of the chromatin regulator extra sex combs (esc).
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Affiliation(s)
| | | | - Spencer L Nystrom
- University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Daniel J McKay
- University of North Carolina at Chapel Hill, Chapel Hill, United States
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160
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Hörmann N, Schilling T, Ali AH, Serbe E, Mayer C, Borst A, Pujol-Martí J. A combinatorial code of transcription factors specifies subtypes of visual motion-sensing neurons in Drosophila. Development 2020; 147:223179. [PMID: 32238425 PMCID: PMC7240302 DOI: 10.1242/dev.186296] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 03/20/2020] [Indexed: 12/21/2022]
Abstract
Direction-selective T4/T5 neurons exist in four subtypes, each tuned to visual motion along one of the four cardinal directions. Along with their directional tuning, neurons of each T4/T5 subtype orient their dendrites and project their axons in a subtype-specific manner. Directional tuning, thus, appears strictly linked to morphology in T4/T5 neurons. How the four T4/T5 subtypes acquire their distinct morphologies during development remains largely unknown. Here, we investigated when and how the dendrites of the four T4/T5 subtypes acquire their specific orientations, and profiled the transcriptomes of all T4/T5 neurons during this process. This revealed a simple and stable combinatorial code of transcription factors defining the four T4/T5 subtypes during their development. Changing the combination of transcription factors of specific T4/T5 subtypes resulted in predictable and complete conversions of subtype-specific properties, i.e. dendrite orientation and matching axon projection pattern. Therefore, a combinatorial code of transcription factors coordinates the development of dendrite and axon morphologies to generate anatomical specializations that differentiate subtypes of T4/T5 motion-sensing neurons. Summary: Morphological and transcriptomic analyses allowed the identification of a combinatorial code of transcription factors that controls the development of subtype-specific morphologies in motion-detecting neurons of the Drosophila visual system.
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Affiliation(s)
- Nikolai Hörmann
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Tabea Schilling
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Aicha Haji Ali
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Etienne Serbe
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Christian Mayer
- Laboratory of Neurogenomics, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Alexander Borst
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Jesús Pujol-Martí
- Department of Circuits - Computation - Models, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
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161
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An Optogenetic Method to Study Signal Transduction in Intestinal Stem Cell Homeostasis. J Mol Biol 2020; 432:3159-3176. [DOI: 10.1016/j.jmb.2020.03.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/09/2020] [Accepted: 03/12/2020] [Indexed: 02/07/2023]
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162
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Basigin Associates with Integrin in Order to Regulate Perineurial Glia and Drosophila Nervous System Morphology. J Neurosci 2020; 40:3360-3373. [PMID: 32265259 DOI: 10.1523/jneurosci.1397-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 03/03/2020] [Accepted: 03/09/2020] [Indexed: 12/12/2022] Open
Abstract
The Drosophila nervous system is ensheathed by a layer of outer glial cells, the perineurial glia, and a specialized extracellular matrix, the neural lamella. The function of perineurial glial cells and how they interact with the extracellular matrix are just beginning to be elucidated. Integrin-based focal adhesion complexes link the glial membrane to the extracellular matrix, but little is known about integrin's regulators in the glia. The transmembrane Ig domain protein Basigin/CD147/EMMPRIN is highly expressed in the perineurial glia surrounding the Drosophila larval nervous system. Here we show that Basigin associates with integrin at the focal adhesions to uphold the structure of the glia-extracellular matrix sheath. Knockdown of Basigin in perineurial glia using RNAi results in significant shortening of the ventral nerve cord, compression of the glia and extracellular matrix in the peripheral nerves, and reduction in larval locomotion. We determined that Basigin is expressed in close proximity to integrin at the glial membrane, and that expression of the extracellular integrin-binding domain of Basigin is sufficient to rescue peripheral glial compression. We also found that a reduction in expression of integrin at the membrane rescues the ventral nerve cord shortening, peripheral glial compression, and locomotor phenotypes, and that reduction in the integrin-binding protein Talin can partially rescue glial compression. These results identify Basigin as a potential negative regulator of integrin in the glia, supporting proper glial and extracellular matrix ensheathment of the nervous system.SIGNIFICANCE STATEMENT The glial cells and extracellular matrix play important roles in supporting and protecting the nervous system, but the interactions between these components have not been well characterized. Our study identified expression of a conserved Ig superfamily protein, Basigin, at the glial membrane of Drosophila where it associates with the integrin-based focal adhesion complexes to ensure proper ensheathment of the CNS and PNS. Loss of Basigin in the glia results in an overall compression of the nervous system due to integrin dysregulation, which causes locomotor defects in the animals. This underlies the importance of glia-matrix communication for structural and functional support of the nervous system.
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163
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Cerqueira Campos F, Dennis C, Alégot H, Fritsch C, Isabella A, Pouchin P, Bardot O, Horne-Badovinac S, Mirouse V. Oriented basement membrane fibrils provide a memory for F-actin planar polarization via the Dystrophin-Dystroglycan complex during tissue elongation. Development 2020; 147:dev.186957. [PMID: 32156755 DOI: 10.1242/dev.186957] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/24/2020] [Indexed: 12/31/2022]
Abstract
How extracellular matrix contributes to tissue morphogenesis is still an open question. In the Drosophila ovarian follicle, it has been proposed that after Fat2-dependent planar polarization of the follicle cell basal domain, oriented basement membrane (BM) fibrils and F-actin stress fibers constrain follicle growth, promoting its axial elongation. However, the relationship between BM fibrils and stress fibers and their respective impact on elongation are unclear. We found that Dystroglycan (Dg) and Dystrophin (Dys) are involved in BM fibril deposition. Moreover, they also orient stress fibers, by acting locally and in parallel to Fat2. Importantly, Dg-Dys complex-mediated cell-autonomous control of F-actin fiber orientation relies on the preceding BM fibril deposition, indicating two distinct but interdependent functions. Thus, the Dg-Dys complex works as a crucial organizer of the epithelial basal domain, regulating both F-actin and BM. Furthermore, BM fibrils act as a persistent cue for the orientation of stress fibers that are the main effector of elongation.
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Affiliation(s)
- Fabiana Cerqueira Campos
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Cynthia Dennis
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Hervé Alégot
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Cornelia Fritsch
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Adam Isabella
- Committee on Development, Regeneration and Stem Cell Biology, and Department of Molecular Genetics and Cell Biology - The University of Chicago, 920 East 58th Street, Chicago IL 60653, USA
| | - Pierre Pouchin
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Olivier Bardot
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
| | - Sally Horne-Badovinac
- Committee on Development, Regeneration and Stem Cell Biology, and Department of Molecular Genetics and Cell Biology - The University of Chicago, 920 East 58th Street, Chicago IL 60653, USA
| | - Vincent Mirouse
- iGReD (Institute of Genetics, Reproduction and Development), Université Clermont Auvergne - UMR CNRS 6293 - INSERM U1103, Faculté de Médecine, 28 Place Henri-Dunant, 63000 Clermont-Ferrand, France
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164
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Jevitt A, Chatterjee D, Xie G, Wang XF, Otwell T, Huang YC, Deng WM. A single-cell atlas of adult Drosophila ovary identifies transcriptional programs and somatic cell lineage regulating oogenesis. PLoS Biol 2020; 18:e3000538. [PMID: 32339165 PMCID: PMC7205450 DOI: 10.1371/journal.pbio.3000538] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 05/07/2020] [Accepted: 03/27/2020] [Indexed: 12/28/2022] Open
Abstract
Oogenesis is a complex developmental process that involves spatiotemporally regulated coordination between the germline and supporting, somatic cell populations. This process has been modeled extensively using the Drosophila ovary. Although different ovarian cell types have been identified through traditional means, the large-scale expression profiles underlying each cell type remain unknown. Using single-cell RNA sequencing technology, we have built a transcriptomic data set for the adult Drosophila ovary and connected tissues. Using this data set, we identified the transcriptional trajectory of the entire follicle-cell population over the course of their development from stem cells to the oogenesis-to-ovulation transition. We further identify expression patterns during essential developmental events that take place in somatic and germline cell types such as differentiation, cell-cycle switching, migration, symmetry breaking, nurse-cell engulfment, egg-shell formation, and corpus luteum signaling. Extensive experimental validation of unique expression patterns in both ovarian and nearby, nonovarian cells also led to the identification of many new cell type-and stage-specific markers. The inclusion of several nearby tissue types in this data set also led to our identification of functional convergence in expression between distantly related cell types such as the immune-related genes that were similarly expressed in immune cells (hemocytes) and ovarian somatic cells (stretched cells) during their brief phagocytic role in nurse-cell engulfment. Taken together, these findings provide new insight into the temporal regulation of genes in a cell-type specific manner during oogenesis and begin to reveal the relatedness in expression between cell and tissues types.
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Affiliation(s)
- Allison Jevitt
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Deeptiman Chatterjee
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Gengqiang Xie
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Taylor Otwell
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
| | - Wu-Min Deng
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana, United States of America
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165
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Chowdhury T, Calhoun RM, Bruch K, Moehring AJ. The fruitless gene affects female receptivity and species isolation. Proc Biol Sci 2020; 287:20192765. [PMID: 32208837 DOI: 10.1098/rspb.2019.2765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Female mate rejection acts as a major selective force within species, and can serve as a reproductive barrier between species. In spite of its critical role in fitness and reproduction, surprisingly little is known about the genetic or neural basis of variation in female mate choice. Here, we identify fruitless as a gene affecting female receptivity within Drosophila melanogaster, as well as female Drosophila simulans rejection of male D. melanogaster. Of the multiple transcripts this gene produces, by far the most widely studied is the sex-specifically spliced transcript involved in the sex determination pathway. However, we find that female rejection behaviour is affected by a non-sex-specifically spliced fruitless transcript. This is the first implication of fruitless in female behaviour, and the first behavioural role identified for a fruitless non-sex-specifically spliced transcript. We found that this locus does not influence preferences via a single sensory modality, examining courtship song, antennal pheromone perception, or perception of substrate vibrations, and we conclude that fruitless influences mate choice via the integration of multiple signals or through another sensory modality.
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Affiliation(s)
- Tabashir Chowdhury
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
| | - Ryan M Calhoun
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
| | - Katrina Bruch
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
| | - Amanda J Moehring
- Department of Biology, Western University, London, Ontario, Canada N6A 5B7
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166
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Li G, Forero MG, Wentzell JS, Durmus I, Wolf R, Anthoney NC, Parker M, Jiang R, Hasenauer J, Strausfeld NJ, Heisenberg M, Hidalgo A. A Toll-receptor map underlies structural brain plasticity. eLife 2020; 9:52743. [PMID: 32066523 PMCID: PMC7077983 DOI: 10.7554/elife.52743] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 02/12/2020] [Indexed: 12/28/2022] Open
Abstract
Experience alters brain structure, but the underlying mechanism remained unknown. Structural plasticity reveals that brain function is encoded in generative changes to cells that compete with destructive processes driving neurodegeneration. At an adult critical period, experience increases fiber number and brain size in Drosophila. Here, we asked if Toll receptors are involved. Tolls demarcate a map of brain anatomical domains. Focusing on Toll-2, loss of function caused apoptosis, neurite atrophy and impaired behaviour. Toll-2 gain of function and neuronal activity at the critical period increased cell number. Toll-2 induced cycling of adult progenitor cells via a novel pathway, that antagonized MyD88-dependent quiescence, and engaged Weckle and Yorkie downstream. Constant knock-down of multiple Tolls synergistically reduced brain size. Conditional over-expression of Toll-2 and wek at the adult critical period increased brain size. Through their topographic distribution, Toll receptors regulate neuronal number and brain size, modulating structural plasticity in the adult brain. Everything that you experience leaves its mark on your brain. When you learn something new, the neurons involved in the learning episode grow new projections and form new connections. Your brain may even produce new neurons. Physical exercise can induce similar changes, as can taking antidepressants. By contrast, stress, depression, ageing and disease can have the opposite effect, triggering neurons to break down and even die. The ability of the brain to change in response to experience is known as structural plasticity, and it is in a tug-of-war with processes that drive neurodegeneration. Structural plasticity occurs in other species too: for example, it was described in the fruit fly more than a quarter of a century ago. Yet, the molecular mechanisms underlying structural plasticity remain unclear. Li et al. now show that, in fruit flies, this plasticity involves Toll receptors, a family of proteins present in the brain but best known for their role in the immune system. Fruit flies have nine different Toll receptors, the most abundant being Toll-2. When activated, these proteins can trigger a series of molecular events in a cell. Li et al. show that increasing the amount of Toll-2 in the fly brain makes the brain produce new neurons. Activating neurons in a brain region has the same effect, and this increase in neuron number also depends on Toll-2. By contrast, reducing the amount of Toll-2 causes neurons to lose their projections and connections, and to die, and impairs fly behaviour. Li et al. also show that each Toll receptor has a unique distribution across the fly brain. Different types of experiences activate different brain regions, and therefore different Toll receptors. These go on to trigger a common molecular cascade, but they modulate it such as to result in distinct outcomes. By working together in different combinations, Toll receptors can promote either the death or survival of neurons, and they can also drive specific brain cells to remain dormant or to produce new neurons. By revealing how experience changes the brain, Li et al. provide clues to the way neurons work and form; these findings may also help to find new treatments for disorders that change brain structure, such as certain psychiatric conditions. Toll-like receptors in humans could thus represent a promising new target for drug discovery.
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Affiliation(s)
- Guiyi Li
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom.,Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Manuel G Forero
- Facultad de Ingeniería, Universidad de Ibagué, Ibagué, Colombia
| | - Jill S Wentzell
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Ilgim Durmus
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Reinhard Wolf
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Niki C Anthoney
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Mieczyslaw Parker
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Ruiying Jiang
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Jacob Hasenauer
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Nicholas James Strausfeld
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany.,Neuroscience, University of Arizona College of Science, Tucson, United States
| | - Martin Heisenberg
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Alicia Hidalgo
- Neurodevelopment Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
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167
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Huang A, Rupprecht JF, Saunders TE. Embryonic geometry underlies phenotypic variation in decanalized conditions. eLife 2020; 9:e47380. [PMID: 32048988 PMCID: PMC7032927 DOI: 10.7554/elife.47380] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 02/11/2020] [Indexed: 11/13/2022] Open
Abstract
During development, many mutations cause increased variation in phenotypic outcomes, a phenomenon termed decanalization. Phenotypic discordance is often observed in the absence of genetic and environmental variations, but the mechanisms underlying such inter-individual phenotypic discordance remain elusive. Here, using the anterior-posterior (AP) patterning of the Drosophila embryo, we identified embryonic geometry as a key factor predetermining patterning outcomes under decanalizing mutations. With the wild-type AP patterning network, we found that AP patterning is robust to variations in embryonic geometry; segmentation gene expression remains reproducible even when the embryo aspect ratio is artificially reduced by more than twofold. In contrast, embryonic geometry is highly predictive of individual patterning defects under decanalized conditions of either increased bicoid (bcd) dosage or bcd knockout. We showed that the phenotypic discordance can be traced back to variations in the gap gene expression, which is rendered sensitive to the geometry of the embryo under mutations.
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Affiliation(s)
- Anqi Huang
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
| | - Jean-François Rupprecht
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
- CNRS and Turing Center for Living Systems, Centre de Physique Théorique, Aix-Marseille UniversitéMarseilleFrance
| | - Timothy E Saunders
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
- Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Institute of Molecular and Cell Biology, Proteos, A*StarSingaporeSingapore
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168
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Kakanj P, Eming SA, Partridge L, Leptin M. Long-term in vivo imaging of Drosophila larvae. Nat Protoc 2020; 15:1158-1187. [DOI: 10.1038/s41596-019-0282-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/09/2019] [Indexed: 02/07/2023]
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169
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Amourda C, Saunders TE. The mirtron miR-1010 functions in concert with its host gene SKIP to balance elevation of nAcRβ2. Sci Rep 2020; 10:1688. [PMID: 32015391 PMCID: PMC6997181 DOI: 10.1038/s41598-020-58655-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/19/2020] [Indexed: 02/02/2023] Open
Abstract
Mirtrons are non-canonical miRNAs arising by splicing and debranching from short introns. A plethora of introns have been inferred by computational analyses as potential mirtrons. Yet, few have been experimentally validated and their functions, particularly in relation to their host genes, remain poorly understood. Here, we found that Drosophila larvae lacking either the mirtron miR-1010 or its binding site in the nicotinic acetylcholine receptor β2 (nAcRβ2) 3′UTR fail to grow properly and pupariate. Increase of cortical nAcRβ2 mediated by neural activity elevates the level of intracellular Ca2+, which in turn activates CaMKII and, further downstream, the transcription factor Adf-1. We show that miR-1010 downregulates nAcRβ2. We reveal that Adf-1 initiates the expression of SKIP, the host gene of miR-1010. Preventing synaptic potentials from overshooting their optimal range requires both SKIP to temper synaptic potentials (incoherent feedforward loop) and miR-1010 to reduce nAcRβ2 mRNA levels (negative feedback loop). Our results demonstrate how a mirtron, in coordination with its host gene, contributes to maintaining appropriate receptor levels, which in turn may play a role in maintaining homeostasis.
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Affiliation(s)
- Christopher Amourda
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore. .,MRC London Institute of Medical Science, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore. .,Department of Biological Sciences, National University of Singapore, Singapore, Singapore. .,Institute of Molecular and Cell Biology, A*Star, Proteos, Singapore.
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170
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Caipo L, González-Ramírez MC, Guzmán-Palma P, Contreras EG, Palominos T, Fuenzalida-Uribe N, Hassan BA, Campusano JM, Sierralta J, Oliva C. Slit neuronal secretion coordinates optic lobe morphogenesis in Drosophila. Dev Biol 2020; 458:32-42. [PMID: 31606342 DOI: 10.1016/j.ydbio.2019.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 10/04/2019] [Accepted: 10/05/2019] [Indexed: 12/12/2022]
Abstract
The complexity of the nervous system requires the coordination of multiple cellular processes during development. Among them, we find boundary formation, axon guidance, cell migration and cell segregation. Understanding how different cell populations such as glial cells, developing neurons and neural stem cells contribute to the formation of boundaries and morphogenesis in the nervous system is a critical question in neurobiology. Slit is an evolutionary conserved protein essential for the development of the nervous system. For signaling, Slit has to bind to its cognate receptor Robo, a single-pass transmembrane protein. Although the Slit/Robo signaling pathway is well known for its involvement in axon guidance, it has also been associated to boundary formation in the Drosophila visual system. In the optic lobe, Slit is expressed in glial cells, positioned at the boundaries between developing neuropils, and in neurons of the medulla ganglia. Although it has been assumed that glial cells provide Slit to the system, the contribution of the neuronal expression has not been tested. Here, we show that, contrary to what was previously thought, Slit protein provided by medulla neurons is also required for boundary formation and morphogenesis of the optic lobe. Furthermore, tissue specific rescue using modified versions of Slit demonstrates that this protein acts at long range and does not require processing by extracellular proteases. Our data shed new light on our understanding of the cellular mechanisms involved in Slit function in the fly visual system morphogenesis.
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Affiliation(s)
- Lorena Caipo
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile; Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - M Constanza González-Ramírez
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Pablo Guzmán-Palma
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Esteban G Contreras
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Tomás Palominos
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Nicolás Fuenzalida-Uribe
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Bassem A Hassan
- Institut du Cerveau et de la Moelle Epinière (ICM) - Sorbonne Université, Hôpital Pitié-Salpêtrière, Inserm, CNRS, Paris, France
| | - Jorge M Campusano
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Jimena Sierralta
- Department of Neuroscience and Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Independencia 1027, Santiago, Chile
| | - Carlos Oliva
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av Libertador Bernardo O'Higgins 340, Santiago, Chile.
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171
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Werner J, Arian J, Bernhardt I, Ryglewski S, Duch C. Differential localization of voltage-gated potassium channels during Drosophila metamorphosis. J Neurogenet 2020; 34:133-150. [PMID: 31997675 DOI: 10.1080/01677063.2020.1715972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neuronal excitability is determined by the combination of different ion channels and their sub-neuronal localization. This study utilizes protein trap fly strains with endogenously tagged channels to analyze the spatial expression patterns of the four Shaker-related voltage-gated potassium channels, Kv1-4, in the larval, pupal, and adult Drosophila ventral nerve cord. We find that all four channels (Shaker, Kv1; Shab, Kv2; Shaw, Kv3; and Shal, Kv4) each show different spatial expression patterns in the Drosophila ventral nerve cord and are predominantly targeted to different sub-neuronal compartments. Shaker is abundantly expressed in axons, Shab also localizes to axons but mostly in commissures, Shaw expression is restricted to distinct parts of neuropils, and Shal is found somatodendritically, but also in axons of identified motoneurons. During early pupal life expression of all four Shaker-related channels is markedly decreased with an almost complete shutdown of expression at early pupal stage 5 (∼30% through metamorphosis). Re-expression of Kv1-4 channels at pupal stage 6 starts with abundant channel localization in neuronal somata, followed by channel targeting to the respective sub-neuronal compartments until late pupal life. The developmental time course of tagged Kv1-4 channel expression corresponds with previously published data on developmental changes in single neuron physiology, thus indicating that protein trap fly strains are a useful tool to analyze developmental regulation of potassium channel expression. Finally, we take advantage of the large diameter of the giant fiber (GF) interneuron to map channel expression onto the axon and axon terminals of an identified interneuron. Shaker, Shaw, and Shal but not Shab channels localize to the non-myelinated GF axonal membrane and axon terminals. This study constitutes a first step toward systematically analyzing sub-neuronal potassium channel localization in Drosophila. Functional implications as well as similarities and differences to Kv1-4 channel localization in mammalian neurons are discussed.
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Affiliation(s)
- Jan Werner
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jashar Arian
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Ida Bernhardt
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stefanie Ryglewski
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Carsten Duch
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
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172
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Hoyer N, Zielke P, Hu C, Petersen M, Sauter K, Scharrenberg R, Peng Y, Kim CC, Han C, Parrish JZ, Soba P. Ret and Substrate-Derived TGF-β Maverick Regulate Space-Filling Dendrite Growth in Drosophila Sensory Neurons. Cell Rep 2020; 24:2261-2272.e5. [PMID: 30157422 DOI: 10.1016/j.celrep.2018.07.092] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/17/2018] [Accepted: 07/27/2018] [Indexed: 12/19/2022] Open
Abstract
Dendrite morphogenesis is a highly regulated process that gives rise to stereotyped receptive fields, which are required for proper neuronal connectivity and function. Specific classes of neurons, including Drosophila class IV dendritic arborization (C4da) neurons, also feature complete space-filling growth of dendrites. In this system, we have identified the substrate-derived TGF-β ligand maverick (mav) as a developmental signal promoting space-filling growth through the neuronal Ret receptor. Both are necessary for radial spreading of C4da neuron dendrites, and Ret is required for neuronal uptake of Mav. Moreover, local changes in Mav levels result in directed dendritic growth toward regions with higher ligand availability. Our results suggest that Mav acts as a substrate-derived secreted signal promoting dendrite growth within not-yet-covered areas of the receptive field to ensure space-filling dendritic growth.
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Affiliation(s)
- Nina Hoyer
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Philip Zielke
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Chun Hu
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Meike Petersen
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Kathrin Sauter
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Robin Scharrenberg
- Research Group Neuronal Development, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Yun Peng
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | | | - Chun Han
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Peter Soba
- Research Group Neuronal Patterning and Connectivity, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany.
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173
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Okamoto N, Yamanaka N. Steroid Hormone Entry into the Brain Requires a Membrane Transporter in Drosophila. Curr Biol 2020; 30:359-366.e3. [PMID: 31928869 DOI: 10.1016/j.cub.2019.11.085] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/14/2019] [Accepted: 11/28/2019] [Indexed: 02/08/2023]
Abstract
Steroid hormones control various aspects of brain development and behavior in metazoans, but how they enter the central nervous system (CNS) through the blood-brain barrier (BBB) remains poorly understood. It is generally believed that steroid hormones freely diffuse through the plasma membrane of the BBB cells to reach the brain [1], because of the predominant "simple diffusion" model of steroid hormone transport across cell membranes. Recently, however, we challenged the simple diffusion model by showing that a Drosophila organic anion-transporting polypeptide (OATP), which we named Ecdysone Importer (EcI), is required for cellular uptake of the primary insect steroid hormone ecdysone [2]. As ecdysone is first secreted into the hemolymph before reaching the CNS [3], our finding raised the question of how ecdysone enters the CNS through the BBB to exert its diverse role in Drosophila brain development. Here, we demonstrate in the Drosophila BBB that EcI is indispensable for ecdysone entry into the CNS to facilitate brain development. EcI is highly expressed in surface glial cells that form the BBB, and EcI knockdown in the BBB suppresses ecdysone signaling within the CNS and blocks ecdysone-mediated neuronal events during development. In an ex vivo culture system, the CNS requires EcI in the BBB to incorporate ecdysone from the culture medium. Our results suggest a transporter-mediated mechanism of steroid hormone entry into the CNS, which may provide important implications in controlling brain development and behavior by regulating steroid hormone permeability across the BBB.
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Affiliation(s)
- Naoki Okamoto
- Department of Entomology, Institute for Integrative Genome Biology, University of California, Riverside, 900 University Ave., Riverside, CA 92521, USA
| | - Naoki Yamanaka
- Department of Entomology, Institute for Integrative Genome Biology, University of California, Riverside, 900 University Ave., Riverside, CA 92521, USA.
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174
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Antioxidant Therapy in Parkinson's Disease: Insights from Drosophila melanogaster. Antioxidants (Basel) 2020; 9:antiox9010052. [PMID: 31936094 PMCID: PMC7023233 DOI: 10.3390/antiox9010052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/03/2020] [Accepted: 01/04/2020] [Indexed: 12/20/2022] Open
Abstract
Reactive oxygen species (ROS) play an important role as endogenous mediators in several cellular signalling pathways. However, at high concentrations they can also exert deleterious effects by reacting with many macromolecules including DNA, proteins and lipids. The precise balance between ROS production and their removal via numerous enzymatic and nonenzymatic molecules is of fundamental importance for cell survival. Accordingly, many neurodegenerative disorders, including Parkinson’s disease (PD), are associated with excessive levels of ROS, which induce oxidative damage. With the aim of coping with the progression of PD, antioxidant compounds are currently receiving increasing attention as potential co-adjuvant molecules in the treatment of these diseases, and many studies have been performed to evaluate the purported protective effects of several antioxidant molecules. In the present review, we present and discuss the relevance of the use of Drosophila melanogaster as an animal model with which to evaluate the therapeutic potential of natural and synthetic antioxidants. The conservation of most of the PD-related genes between humans and D. melanogaster, along with the animal’s rapid life cycle and the versatility of genetic tools, makes fruit flies an ideal experimental system for rapid screening of antioxidant-based treatments.
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175
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Lee YCG, Ventura IM, Rice GR, Chen DY, Colmenares SU, Long M. Rapid Evolution of Gained Essential Developmental Functions of a Young Gene via Interactions with Other Essential Genes. Mol Biol Evol 2020; 36:2212-2226. [PMID: 31187122 DOI: 10.1093/molbev/msz137] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
New genes are of recent origin and only present in a subset of species in a phylogeny. Accumulated evidence suggests that new genes, like old genes that are conserved across species, can also take on important functions and be essential for the survival and reproductive success of organisms. Although there are detailed analyses of the mechanisms underlying new genes' gaining fertility functions, how new genes rapidly become essential for viability remains unclear. We focused on a young retro-duplicated gene (CG7804, which we named Cocoon) in Drosophila that originated between 4 and 10 Ma. We found that, unlike its evolutionarily conserved parental gene, Cocoon has evolved under positive selection and accumulated many amino acid differences at functional sites from the parental gene. Despite its young age, Cocoon is essential for the survival of Drosophila melanogaster at multiple developmental stages, including the critical embryonic stage, and its expression is essential in different tissues from those of its parental gene. Functional genomic analyses found that Cocoon acquired unique DNA-binding sites and has a contrasting effect on gene expression to that of its parental gene. Importantly, Cocoon binding predominantly locates at genes that have other essential functions and/or have multiple gene-gene interactions, suggesting that Cocoon acquired novel essential function to survival through forming interactions that have large impacts on the gene interaction network. Our study is an important step toward deciphering the evolutionary trajectory by which new genes functionally diverge from parental genes and become essential.
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Affiliation(s)
- Yuh Chwen G Lee
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL.,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Iuri M Ventura
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL.,CAPES Foundation, Ministry of Education of Brazil, Brasília, DF, Brazil
| | - Gavin R Rice
- Department of Evolution and Ecology, University of California, Davis, Davis, CA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Dong-Yuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Serafin U Colmenares
- Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL
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176
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Wang H, Foquet B, Dewell RB, Song H, Dierick HA, Gabbiani F. Molecular characterization and distribution of the voltage-gated sodium channel, Para, in the brain of the grasshopper and vinegar fly. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:289-307. [PMID: 31902005 DOI: 10.1007/s00359-019-01396-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/10/2019] [Accepted: 12/14/2019] [Indexed: 11/29/2022]
Abstract
Voltage-gated sodium (NaV) channels, encoded by the gene para, play a critical role in the rapid processing and propagation of visual information related to collision avoidance behaviors. We investigated their localization by immunostaining the optic lobes and central brain of the grasshopper Schistocerca americana and the vinegar fly Drosophila melanogaster with an antibody that recognizes the channel peptide domain responsible for fast inactivation gating. NaV channels were detected at high density at all stages of development. In the optic lobe, they revealed stereotypically repeating fascicles consistent with the regular structure of the eye. In the central brain, major axonal tracts were strongly labeled, particularly in the grasshopper olfactory system. We used the NaV channel sequence of Drosophila to identify an ortholog in the transcriptome of Schistocerca. The grasshopper, vinegar fly, and human NaV channels exhibit a high degree of conservation at gating and ion selectivity domains. Comparison with three species evolutionarily close to Schistocerca identified splice variants of Para and their relation to those of Drosophila. The anatomical distribution of NaV channels molecularly analogous to those of humans in grasshoppers and vinegar flies provides a substrate for rapid signal propagation and visual processing in the context of visually-guided collision avoidance.
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Affiliation(s)
- Hongxia Wang
- Department of Neuroscience, Baylor College of Medicine, Houston, USA
| | - Bert Foquet
- Department of Entomology, Texas A&M University, College Station, USA
| | - Richard B Dewell
- Department of Neuroscience, Baylor College of Medicine, Houston, USA
| | - Hojun Song
- Department of Entomology, Texas A&M University, College Station, USA
| | - Herman A Dierick
- Department of Neuroscience, Baylor College of Medicine, Houston, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA
| | - Fabrizio Gabbiani
- Department of Neuroscience, Baylor College of Medicine, Houston, USA. .,Department of Electrical and Computer Engineering, Rice University, Houston, USA.
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177
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Neurochemical Organization of the Drosophila Brain Visualized by Endogenously Tagged Neurotransmitter Receptors. Cell Rep 2020; 30:284-297.e5. [DOI: 10.1016/j.celrep.2019.12.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 10/19/2019] [Accepted: 12/06/2019] [Indexed: 02/08/2023] Open
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178
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Walcott KCE, Mauthner SE, Tsubouchi A, Robertson J, Tracey WD. The Drosophila Small Conductance Calcium-Activated Potassium Channel Negatively Regulates Nociception. Cell Rep 2019; 24:3125-3132.e3. [PMID: 30231996 PMCID: PMC6454897 DOI: 10.1016/j.celrep.2018.08.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 06/11/2018] [Accepted: 08/23/2018] [Indexed: 12/20/2022] Open
Abstract
Inhibition of nociceptor activity is important for the prevention of spontaneous pain and hyperalgesia. To identify the critical K+ channels that regulate nociceptor excitability, we performed a forward genetic screen using a Drosophila larval nociception paradigm. Knockdown of three K+ channel loci, the small conductance calcium-activated potassium channel (SK), seizure, and tiwaz, causes marked hypersensitive nociception behaviors. In more detailed studies of SK, we found that hypersensitive phenotypes can be recapitulated with a genetically null allele. Optical recordings from nociceptive neurons showed a significant increase in mechanically activated Ca2+ signals in SK mutant nociceptors. SK is expressed in peripheral neurons, including nociceptive neurons. Interestingly, SK proteins localize to axons of these neurons but are not detected in dendrites. Our findings suggest a major role for SK channels in the regulation of nociceptor excitation and are inconsistent with the hypothesis that the important site of action is within dendrites. Walcott et al. performed a forward genetic screen and identify three potassium channel subunits that negatively regulate nociception in Drosophila larvae. In a more detailed investigation of the SK channel, null mutants, rescue experiments, optical recordings, and protein localization studies indicate a functional role for SK in nociceptor excitability.
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Affiliation(s)
- Kia C E Walcott
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Stephanie E Mauthner
- Gill Center for Biomolecular Research, Indiana University, Bloomington, IN, USA; Department of Biology, Indiana University, Bloomington, IN, USA
| | - Asako Tsubouchi
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Jessica Robertson
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - W Daniel Tracey
- Gill Center for Biomolecular Research, Indiana University, Bloomington, IN, USA; Department of Biology, Indiana University, Bloomington, IN, USA; Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.
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179
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Bellen HJ, Wangler MF, Yamamoto S. The fruit fly at the interface of diagnosis and pathogenic mechanisms of rare and common human diseases. Hum Mol Genet 2019; 28:R207-R214. [PMID: 31227826 PMCID: PMC6872428 DOI: 10.1093/hmg/ddz135] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 05/31/2019] [Accepted: 06/07/2019] [Indexed: 12/12/2022] Open
Abstract
Drosophila melanogaster is a unique, powerful genetic model organism for studying a broad range of biological questions. Human studies that probe the genetic causes of rare and undiagnosed diseases using massive-parallel sequencing often require complementary gene function studies to determine if and how rare variants affect gene function. These studies also provide inroads to disease mechanisms and therapeutic targets. In this review we discuss strategies for functional studies of rare human variants in Drosophila. We focus on our experience in establishing a Drosophila core of the Model Organisms Screening Center for the Undiagnosed Diseases Network (UDN) and concurrent fly studies with other large genomic rare disease research efforts such as the Centers for Mendelian Genomics. We outline four major strategies that use the latest technology in fly genetics to understand the impact of human variants on gene function. We also mention general concepts in probing disease mechanisms, therapeutics and using rare disease to understand common diseases. Drosophila is and will continue to be a fundamental genetic model to identify new disease-causing variants, pathogenic mechanisms and drugs that will impact medicine.
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Affiliation(s)
- Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine (BCM), Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX , USA
- Howard Hughes Medical Institute, Houston, TX, USA
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX , USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine (BCM), Houston, TX, USA
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX , USA
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180
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Protein trap: a new Swiss army knife for geneticists? Mol Biol Rep 2019; 47:1445-1458. [PMID: 31728729 DOI: 10.1007/s11033-019-05181-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/04/2019] [Indexed: 10/25/2022]
Abstract
The protein trap is a powerful tool for genetic and biochemical studies of gene function in the animal kingdom. Although the original protein trap was developed for flies, it can be easily adapted to other multicellular organisms, both known models and ones with an unsequenced genome. The protein trap has been successfully applied to the fruit fly, crustaceans Parhyale hawaiensis, zebrafish, and insect and animal cell cultures. This approach is based on the integration into genes of an artificial exon that carries DNA encoding a fluorescent marker, standardized immunoepitopes, an integrase docking site, and splice acceptor and donor sites. The protein trap for cell cultures additionally contains an antibiotic resistance gene, which facilitates the selection of trapped clones. Resulting chimeric tagged mRNAs can be interfered by dsRNA against GFP (iGFPi-in vivo GFP interference), or the chimeric proteins can be efficiently knocked down by deGradFP technology. Both RNA and protein knockdowns produce a strong loss of function phenotype in tagged cells. The fluorescent and protein affinity tags can be used for tagged protein localisation within the cell and for identifying their binding partners in their native complexes. Insertion into protein trap integrase docking sites allows the replacement of trap contents by any new constructs, including other markers, cell toxins, stop-codons, and binary expression systems such as GAL4/UAS, LexA/LexAop and QF/QUAS, that reliably reflect endogenous gene expression. A distinctive feature of the protein trap approach is that all manipulations with a gene or its product occur only in the endogenous locus, which cannot be achieved by any other method.
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181
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Link N, Chung H, Jolly A, Withers M, Tepe B, Arenkiel BR, Shah PS, Krogan NJ, Aydin H, Geckinli BB, Tos T, Isikay S, Tuysuz B, Mochida GH, Thomas AX, Clark RD, Mirzaa GM, Lupski JR, Bellen HJ. Mutations in ANKLE2, a ZIKA Virus Target, Disrupt an Asymmetric Cell Division Pathway in Drosophila Neuroblasts to Cause Microcephaly. Dev Cell 2019; 51:713-729.e6. [PMID: 31735666 DOI: 10.1016/j.devcel.2019.10.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/19/2019] [Accepted: 10/14/2019] [Indexed: 12/12/2022]
Abstract
The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division.
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Affiliation(s)
- Nichole Link
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Hyunglok Chung
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Angad Jolly
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA
| | - Marjorie Withers
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Burak Tepe
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA
| | - Priya S Shah
- Department of Chemical Engineering and Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute for Quantitative Biosciences, QB3, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hatip Aydin
- Center of Genetics Diagnosis, Zeynep Kamil Maternity and Children's Training and Research Hospital, Istanbul, Turkey
| | - Bilgen B Geckinli
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul, Turkey
| | - Tulay Tos
- Department of Medical Genetics, Dr. Sami Ulus Research and Training Hospital of Women's and Children's Health and Diseases, Ankara, Turkey
| | - Sedat Isikay
- Department of Physiotherapy and Rehabilitation, Hasan Kalyoncu University, School of Health Sciences, Gaziantep, Turkey
| | - Beyhan Tuysuz
- Department of Pediatrics, Istanbul University-Cerrahpasa, Medical Faculty, Istanbul, Turkey
| | - Ganesh H Mochida
- Division of Genetics and Genomics, Department of Pediatrics and Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ajay X Thomas
- Department of Pediatrics, Section of Neurology and Developmental Neuroscience, BCM, Houston, TX 77030, USA; Section of Child Neurology, Texas Children's Hospital, Houston, TX 77030, USA
| | - Robin D Clark
- Division of Medical Genetics, Department of Pediatrics, Loma Linda University Medical Center, Loma Linda, CA 92354, USA
| | - Ghayda M Mirzaa
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98105, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Department of Pediatrics, BCM, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; MD/PhD Medical Scientist Training Program and MHG Graduate program, BCM, Houston, TX 77030, USA; Program in Developmental Biology, BCM, Houston, TX 77030, USA.
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182
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Aso Y, Ray RP, Long X, Bushey D, Cichewicz K, Ngo TT, Sharp B, Christoforou C, Hu A, Lemire AL, Tillberg P, Hirsh J, Litwin-Kumar A, Rubin GM. Nitric oxide acts as a cotransmitter in a subset of dopaminergic neurons to diversify memory dynamics. eLife 2019; 8:49257. [PMID: 31724947 PMCID: PMC6948953 DOI: 10.7554/elife.49257] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
Animals employ diverse learning rules and synaptic plasticity dynamics to record temporal and statistical information about the world. However, the molecular mechanisms underlying this diversity are poorly understood. The anatomically defined compartments of the insect mushroom body function as parallel units of associative learning, with different learning rates, memory decay dynamics and flexibility (Aso and Rubin, 2016). Here, we show that nitric oxide (NO) acts as a neurotransmitter in a subset of dopaminergic neurons in Drosophila. NO's effects develop more slowly than those of dopamine and depend on soluble guanylate cyclase in postsynaptic Kenyon cells. NO acts antagonistically to dopamine; it shortens memory retention and facilitates the rapid updating of memories. The interplay of NO and dopamine enables memories stored in local domains along Kenyon cell axons to be specialized for predicting the value of odors based only on recent events. Our results provide key mechanistic insights into how diverse memory dynamics are established in parallel memory systems.
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Affiliation(s)
- Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Robert P Ray
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Xi Long
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Daniel Bushey
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Karol Cichewicz
- Department of Biology, University of Virginia, Charlottesville, United States
| | - Teri-Tb Ngo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brandi Sharp
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - Amy Hu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Andrew L Lemire
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Paul Tillberg
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jay Hirsh
- Department of Biology, University of Virginia, Charlottesville, United States
| | - Ashok Litwin-Kumar
- Department of Neuroscience, Columbia University, New York, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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183
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Ansar M, Chung HL, Al-Otaibi A, Elagabani MN, Ravenscroft TA, Paracha SA, Scholz R, Abdel Magid T, Sarwar MT, Shah SF, Qaisar AA, Makrythanasis P, Marcogliese PC, Kamsteeg EJ, Falconnet E, Ranza E, Santoni FA, Aldhalaan H, Al-Asmari A, Faqeih EA, Ahmed J, Kornau HC, Bellen HJ, Antonarakis SE. Bi-allelic Variants in IQSEC1 Cause Intellectual Disability, Developmental Delay, and Short Stature. Am J Hum Genet 2019; 105:907-920. [PMID: 31607425 DOI: 10.1016/j.ajhg.2019.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/11/2019] [Indexed: 12/30/2022] Open
Abstract
We report two consanguineous families with probands that exhibit intellectual disability, developmental delay, short stature, aphasia, and hypotonia in which homozygous non-synonymous variants were identified in IQSEC1 (GenBank: NM_001134382.3). In a Pakistani family, the IQSEC1 segregating variant is c.1028C>T (p.Thr343Met), while in a Saudi Arabian family the variant is c.962G>A (p.Arg321Gln). IQSEC1-3 encode guanine nucleotide exchange factors for the small GTPase ARF6 and their loss affects a variety of actin-dependent cellular processes, including AMPA receptor trafficking at synapses. The ortholog of IQSECs in the fly is schizo and its loss affects growth cone guidance at the midline in the CNS, also an actin-dependent process. Overexpression of the reference IQSEC1 cDNA in wild-type flies is lethal, but overexpression of the two variant IQSEC1 cDNAs did not affect viability. Loss of schizo caused embryonic lethality that could be rescued to 2nd instar larvae by moderate expression of the human reference cDNA. However, the p.Arg321Gln and p.Thr343Met variants failed to rescue embryonic lethality. These data indicate that the variants behave as loss-of-function mutations. We also show that schizo in photoreceptors is required for phototransduction. Finally, mice with a conditional Iqsec1 deletion in cortical neurons exhibited an increased density of dendritic spines with an immature morphology. The phenotypic similarity of the affecteds and the functional experiments in flies and mice indicate that IQSEC1 variants are the cause of a recessive disease with intellectual disability, developmental delay, and short stature, and that axonal guidance and dendritic projection defects as well as dendritic spine dysgenesis may underlie disease pathogenesis.
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184
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Kurmangaliyev YZ, Yoo J, LoCascio SA, Zipursky SL. Modular transcriptional programs separately define axon and dendrite connectivity. eLife 2019; 8:50822. [PMID: 31687928 PMCID: PMC6855804 DOI: 10.7554/elife.50822] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/04/2019] [Indexed: 01/31/2023] Open
Abstract
Patterns of synaptic connectivity are remarkably precise and complex. Single-cell RNA sequencing has revealed a vast transcriptional diversity of neurons. Nevertheless, a clear logic underlying the transcriptional control of neuronal connectivity has yet to emerge. Here, we focused on Drosophila T4/T5 neurons, a class of closely related neuronal subtypes with different wiring patterns. Eight subtypes of T4/T5 neurons are defined by combinations of two patterns of dendritic inputs and four patterns of axonal outputs. Single-cell profiling during development revealed distinct transcriptional programs defining each dendrite and axon wiring pattern. These programs were defined by the expression of a few transcription factors and different combinations of cell surface proteins. Gain and loss of function studies provide evidence for independent control of different wiring features. We propose that modular transcriptional programs for distinct wiring features are assembled in different combinations to generate diverse patterns of neuronal connectivity.
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Affiliation(s)
- Yerbol Z Kurmangaliyev
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Juyoun Yoo
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, United States
| | - Samuel A LoCascio
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - S Lawrence Zipursky
- Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
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185
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Scott JG, Buchon N. Drosophila melanogaster as a powerful tool for studying insect toxicology. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 161:95-103. [PMID: 31685202 DOI: 10.1016/j.pestbp.2019.09.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 06/10/2023]
Abstract
Insecticides are valuable and widely used tools for the control of pest insects. Despite the use of synthetic insecticides for >50 years, we continue to have a limited understanding of the genes that influence the key steps of the poisoning process. Major barriers for improving our understanding of insecticide toxicity have included a narrow range of tools and/or a large number of candidate genes that could be involved in the poisoning process. Herein, we discuss the numerous tools and resources available in Drosophila melanogaster that could be brought to bear to improve our understanding of the processes determining insecticide toxicity. These include unbiased approaches such as forward genetic screens, population genetic methods and candidate gene approaches. Examples are provided to showcase how D. melanogaster has been successfully used for insecticide toxicology studies in the past, and ideas for future studies using this valuable insect are discussed.
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Affiliation(s)
- Jeffrey G Scott
- Department of Entomology, Comstock Hall, Cornell University, Ithaca, NY, USA.
| | - Nicolas Buchon
- Department of Entomology, Comstock Hall, Cornell University, Ithaca, NY, USA
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186
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Benner L, Castro EA, Whitworth C, Venken KJT, Yang H, Fang J, Oliver B, Cook KR, Lerit DA. Drosophila Heterochromatin Stabilization Requires the Zinc-Finger Protein Small Ovary. Genetics 2019; 213:877-895. [PMID: 31558581 PMCID: PMC6827387 DOI: 10.1534/genetics.119.302590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/21/2019] [Indexed: 02/04/2023] Open
Abstract
Heterochromatin-mediated repression is essential for controlling the expression of transposons and for coordinated cell type-specific gene regulation. The small ovary (sov) locus was identified in a screen for female-sterile mutations in Drosophila melanogaster, and mutants show dramatic ovarian morphogenesis defects. We show that the null sov phenotype is lethal and map the locus to the uncharacterized gene CG14438, which encodes a nuclear zinc-finger protein that colocalizes with the essential Heterochromatin Protein 1 (HP1a). We demonstrate Sov functions to repress inappropriate gene expression in the ovary, silence transposons, and suppress position-effect variegation in the eye, suggesting a central role in heterochromatin stabilization.
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Affiliation(s)
- Leif Benner
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
- Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Elias A Castro
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Cale Whitworth
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Koen J T Venken
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology
- McNair Medical Institute at the Robert and Janice McNair Foundation
- Dan L. Duncan Cancer Center, Center for Drug Discovery
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Haiwang Yang
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Junnan Fang
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Brian Oliver
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Kevin R Cook
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Dorothy A Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
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187
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Kanca O, Zirin J, Garcia-Marques J, Knight SM, Yang-Zhou D, Amador G, Chung H, Zuo Z, Ma L, He Y, Lin WW, Fang Y, Ge M, Yamamoto S, Schulze KL, Hu Y, Spradling AC, Mohr SE, Perrimon N, Bellen HJ. An efficient CRISPR-based strategy to insert small and large fragments of DNA using short homology arms. eLife 2019; 8:e51539. [PMID: 31674908 PMCID: PMC6855806 DOI: 10.7554/elife.51539] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/31/2019] [Indexed: 12/31/2022] Open
Abstract
We previously reported a CRISPR-mediated knock-in strategy into introns of Drosophila genes, generating an attP-FRT-SA-T2A-GAL4-polyA-3XP3-EGFP-FRT-attP transgenic library for multiple uses (Lee et al., 2018a). The method relied on double stranded DNA (dsDNA) homology donors with ~1 kb homology arms. Here, we describe three new simpler ways to edit genes in flies. We create single stranded DNA (ssDNA) donors using PCR and add 100 nt of homology on each side of an integration cassette, followed by enzymatic removal of one strand. Using this method, we generated GFP-tagged proteins that mark organelles in S2 cells. We then describe two dsDNA methods using cheap synthesized donors flanked by 100 nt homology arms and gRNA target sites cloned into a plasmid. Upon injection, donor DNA (1 to 5 kb) is released from the plasmid by Cas9. The cassette integrates efficiently and precisely in vivo. The approach is fast, cheap, and scalable.
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Affiliation(s)
- Oguz Kanca
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Jonathan Zirin
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | | | - Shannon Marie Knight
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Donghui Yang-Zhou
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Gabriel Amador
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Hyunglok Chung
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Zhongyuan Zuo
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Liwen Ma
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Yuchun He
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Wen-Wen Lin
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Ying Fang
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Ming Ge
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Shinya Yamamoto
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
| | - Karen L Schulze
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Yanhui Hu
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Allan C Spradling
- Department of EmbryologyHoward Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - Stephanie E Mohr
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Norbert Perrimon
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
- Department of GeneticsHarvard Medical SchoolBostonUnited States
| | - Hugo J Bellen
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
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188
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Garcia-Marques J, Yang CP, Espinosa-Medina I, Mok K, Koyama M, Lee T. Unlimited Genetic Switches for Cell-Type-Specific Manipulation. Neuron 2019; 104:227-238.e7. [PMID: 31395429 DOI: 10.1016/j.neuron.2019.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 06/11/2019] [Accepted: 07/03/2019] [Indexed: 01/23/2023]
Abstract
Gaining independent genetic access to discrete cell types is critical to interrogate their biological functions as well as to deliver precise gene therapy. Transcriptomics has allowed us to profile cell populations with extraordinary precision, revealing that cell types are typically defined by a unique combination of genetic markers. Given the lack of adequate tools to target cell types based on multiple markers, most cell types remain inaccessible to genetic manipulation. Here we present CaSSA, a platform to create unlimited genetic switches based on CRISPR/Cas9 (Ca) and the DNA repair mechanism known as single-strand annealing (SSA). CaSSA allows engineering of independent genetic switches, each responding to a specific gRNA. Expressing multiple gRNAs in specific patterns enables multiplex cell-type-specific manipulations and combinatorial genetic targeting. CaSSA is a new genetic tool that conceptually works as an unlimited number of recombinases and will facilitate genetic access to cell types in diverse organisms.
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Affiliation(s)
- Jorge Garcia-Marques
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Ching-Po Yang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Kent Mok
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Minoru Koyama
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Tzumin Lee
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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189
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Hsieh YC, Guo C, Yalamanchili HK, Abreha M, Al-Ouran R, Li Y, Dammer EB, Lah JJ, Levey AI, Bennett DA, De Jager PL, Seyfried NT, Liu Z, Shulman JM. Tau-Mediated Disruption of the Spliceosome Triggers Cryptic RNA Splicing and Neurodegeneration in Alzheimer's Disease. Cell Rep 2019; 29:301-316.e10. [PMID: 31597093 PMCID: PMC6919331 DOI: 10.1016/j.celrep.2019.08.104] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 06/29/2019] [Accepted: 08/29/2019] [Indexed: 12/12/2022] Open
Abstract
In Alzheimer's disease (AD), spliceosomal proteins with critical roles in RNA processing aberrantly aggregate and mislocalize to Tau neurofibrillary tangles. We test the hypothesis that Tau-spliceosome interactions disrupt pre-mRNA splicing in AD. In human postmortem brain with AD pathology, Tau coimmunoprecipitates with spliceosomal components. In Drosophila, pan-neuronal Tau expression triggers reductions in multiple core and U1-specific spliceosomal proteins, and genetic disruption of these factors, including SmB, U1-70K, and U1A, enhances Tau-mediated neurodegeneration. We further show that loss of function in SmB, encoding a core spliceosomal protein, causes decreased survival, progressive locomotor impairment, and neuronal loss, independent of Tau toxicity. Lastly, RNA sequencing reveals a similar profile of mRNA splicing errors in SmB mutant and Tau transgenic flies, including intron retention and non-annotated cryptic splice junctions. In human brains, we confirm cryptic splicing errors in association with neurofibrillary tangle burden. Our results implicate spliceosome disruption and the resulting transcriptome perturbation in Tau-mediated neurodegeneration in AD.
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Affiliation(s)
- Yi-Chen Hsieh
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Caiwei Guo
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hari K Yalamanchili
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Measho Abreha
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Rami Al-Ouran
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yarong Li
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric B Dammer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - James J Lah
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Allan I Levey
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Philip L De Jager
- Center for Translational and Computational Neuroimmunology, Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - Nicholas T Seyfried
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zhandong Liu
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Joshua M Shulman
- 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; Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA.
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190
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Courgeon M, Desplan C. Coordination between stochastic and deterministic specification in the Drosophila visual system. Science 2019; 366:science.aay6727. [PMID: 31582524 DOI: 10.1126/science.aay6727] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/18/2019] [Indexed: 01/05/2023]
Abstract
Sensory systems use stochastic fate specification to increase their repertoire of neuronal types. How these stochastic decisions are coordinated with the development of their targets is unknown. In the Drosophila retina, two subtypes of ultraviolet-sensitive R7 photoreceptors are stochastically specified. In contrast, their targets in the brain are specified through a deterministic program. We identified subtypes of the main target of R7, the Dm8 neurons, each specific to the different subtypes of R7s. Dm8 subtypes are produced in excess by distinct neuronal progenitors, independently from R7. After matching with their cognate R7, supernumerary Dm8s are eliminated by apoptosis. Two interacting cell adhesion molecules, Dpr11 and DIPγ, are essential for the matching of one of the synaptic pairs. These mechanisms allow the qualitative and quantitative matching of R7 and Dm8 and thereby permit the stochastic choice made in R7 to propagate to the brain.
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Affiliation(s)
| | - Claude Desplan
- Department of Biology, New York University, New York, NY 10003, USA.
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191
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Xie X, Tabuchi M, Corver A, Duan G, Wu MN, Kolodkin AL. Semaphorin 2b Regulates Sleep-Circuit Formation in the Drosophila Central Brain. Neuron 2019; 104:322-337.e14. [PMID: 31564592 DOI: 10.1016/j.neuron.2019.07.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 05/09/2019] [Accepted: 07/14/2019] [Indexed: 11/29/2022]
Abstract
The fan-shaped body (FB) neuropil in the Drosophila brain central complex (CX) controls a variety of adult behaviors, including navigation and sleep. How neuronal processes are organized into precise layers and columns in the FB and how alterations in FB neural-circuit wiring affect animal behaviors are unknown. We report here that secreted semaphorin 2b (Sema-2b) acts through its transmembrane receptor Plexin B (PlexB) to locally attract neural processes to specific FB laminae. Aberrant Sema-2b/PlexB signaling leads to select disruptions in neural lamination, and these disruptions result in the formation of ectopic inhibitory connections between subsets of FB neurons. These structural alternations and connectivity defects are associated with changes in fly sleep and arousal, emphasizing the importance of lamination-mediated neural wiring in a central brain region critical for normal sleep behavior.
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Affiliation(s)
- Xiaojun Xie
- Children's Hospital, School of Medicine, Zhejiang University, Hangzhou 310029, China; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Masashi Tabuchi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Abel Corver
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Grace Duan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Mark N Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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192
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Sharifkhodaei Z, Gilbert MM, Auld VJ. Scribble and Discs Large mediate tricellular junction formation. Development 2019; 146:dev.174763. [PMID: 31444218 DOI: 10.1242/dev.174763] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 08/15/2019] [Indexed: 01/22/2023]
Abstract
Junctional complexes that mediate cell adhesion are key to epithelial integrity, cell division and permeability barrier formation. In Drosophila, the scaffolding proteins Scribble (Scrib) and Discs Large (Dlg) are key regulators of epithelial polarity, proliferation, assembly of junctions and protein trafficking. We found that Scrib and Dlg are necessary for the formation of the tricellular junction (TCJ), a unique junction that forms in epithelia at the point of convergence of three neighboring cells. Scrib and Dlg are in close proximity with the TCJ proteins Gliotactin (Gli) and Bark Beetle (Bark), and both are required for TCJ protein recruitment. Loss of Bark or Gli led to basolateral spread of the TCJ complex at the cell corners. Loss of the septate junction proteins Nrx-IV and the Na+/K+ ATPase also resulted in basolateral spread of the entire TCJ complex at the cell corners. The Scrib PDZ1-2 domains and the Dlg GUK domain are necessary for Bark and Gli localization to the TCJ. Overall, we propose a model in which Scrib and Dlg are key components of the TCJ, and form a complex with Bark and Gli.
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Affiliation(s)
- Zohreh Sharifkhodaei
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Mary M Gilbert
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Vanessa J Auld
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
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193
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Drosophila Bruton's Tyrosine Kinase Regulates Habituation Latency and Facilitation in Distinct Mushroom Body Neurons. J Neurosci 2019; 39:8730-8743. [PMID: 31530645 DOI: 10.1523/jneurosci.0633-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 11/21/2022] Open
Abstract
Habituation is the adaptive behavioral outcome of processes engaged in timely devaluation of non-reinforced repetitive stimuli, but the neuronal circuits and molecular mechanisms that underlie them are not well understood. To gain insights into these processes we developed and characterized a habituation assay to repetitive footshocks in mixed sex Drosophila groups and demonstrated that acute neurotransmission from adult α/β mushroom body (MB) neurons prevents premature stimulus devaluation. Herein we demonstrate that activity of the non-receptor tyrosine kinase dBtk protein is required within these neurons to prevent premature habituation. Significantly, we also demonstrate that the complementary process of timely habituation to the repetitive stimulation is facilitated by α'/β' MB neurons and also requires dBtk activity. Hence our results provide initial insights into molecular mechanisms engaged in footshock habituation within distinct MB neurons. Importantly, dBtk attenuation specifically within α'/β' neurons leads to defective habituation, which is readily reversible by administration of the antipsychotics clozapine and risperidone suggesting that the loss of the kinase may dysregulate monoamine receptors within these neurons, whose activity underlies the failure to habituate.SIGNIFICANCE STATEMENT Habituation refers to processes underlying decisions to attend or ignore stimuli, which are pivotal to brain function as they underlie selective attention and learning, but the circuits involved and the molecular mechanisms engaged by the process therein are poorly understood. We demonstrate that habituation to repetitive footshock involves two phases mediated by distinct neurons of the Drosophila mushroom bodies and require the function of the dBtk non-receptor tyrosine kinase. Moreover, habituation failure upon dBtk abrogation in neurons where it is required to facilitate the process is readily reversible by antipsychotics, providing conceptual links to particular symptoms of schizophrenia in humans, also characterized by habituation defects and ameliorated by these pharmaceuticals.
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194
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Villegas SN, Ferres-Marco D, Domínguez M. Using Drosophila Models and Tools to Understand the Mechanisms of Novel Human Cancer Driver Gene Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1167:15-35. [PMID: 31520347 DOI: 10.1007/978-3-030-23629-8_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The formation, overgrowth and metastasis of tumors comprise a complex series of cellular and molecular events resulting from the combined effects of a variety of aberrant signaling pathways, mutations, and epigenetic alterations. Modeling this complexity in vivo requires multiple genes to be manipulated simultaneously, which is technically challenging. Here, we analyze how Drosophila research can further contribute to identifying pathways and elucidating mechanisms underlying novel cancer driver (risk) genes associated with tumor growth and metastasis in humans.
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Affiliation(s)
- Santiago Nahuel Villegas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain.
| | - Dolors Ferres-Marco
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain.
| | - María Domínguez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas (CSIC) and Universidad Miguel Hernández (UMH), Alicante, Spain
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195
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Qin B, Humberg TH, Kim A, Kim HS, Short J, Diao F, White BH, Sprecher SG, Yuan Q. Muscarinic acetylcholine receptor signaling generates OFF selectivity in a simple visual circuit. Nat Commun 2019; 10:4093. [PMID: 31501438 PMCID: PMC6733798 DOI: 10.1038/s41467-019-12104-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 08/21/2019] [Indexed: 11/30/2022] Open
Abstract
ON and OFF selectivity in visual processing is encoded by parallel pathways that respond to either light increments or decrements. Despite lacking the anatomical features to support split channels, Drosophila larvae effectively perform visually-guided behaviors. To understand principles guiding visual computation in this simple circuit, we focus on investigating the physiological properties and behavioral relevance of larval visual interneurons. We find that the ON vs. OFF discrimination in the larval visual circuit emerges through light-elicited cholinergic signaling that depolarizes a cholinergic interneuron (cha-lOLP) and hyperpolarizes a glutamatergic interneuron (glu-lOLP). Genetic studies further indicate that muscarinic acetylcholine receptor (mAchR)/Gαo signaling produces the sign-inversion required for OFF detection in glu-lOLP, the disruption of which strongly impacts both physiological responses of downstream projection neurons and dark-induced pausing behavior. Together, our studies identify the molecular and circuit mechanisms underlying ON vs. OFF discrimination in the Drosophila larval visual system. Drosophila larvae are able to perform visually-guided behaviours yet the molecular and circuit mechanisms for discriminating changes in light intensity are not known. Here, the authors report that ON versus OFF discrimination results from opposing cholinergic and glutamatergic mechanisms.
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Affiliation(s)
- Bo Qin
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | | | - Anna Kim
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Hyong S Kim
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jacob Short
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Fengqiu Diao
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Benjamin H White
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Simon G Sprecher
- Department of Biology, University of Fribourg, 1700, Fribourg, Switzerland
| | - Quan Yuan
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
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196
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Plazaola-Sasieta H, Zhu Q, Gaitán-Peñas H, Rios M, Estévez R, Morey M. Drosophila ClC-a is required in glia of the stem cell niche for proper neurogenesis and wiring of neural circuits. Glia 2019; 67:2374-2398. [PMID: 31479171 PMCID: PMC6851788 DOI: 10.1002/glia.23691] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 01/01/2023]
Abstract
Glial cells form part of the neural stem cell niche and express a wide variety of ion channels; however, the contribution of these channels to nervous system development is poorly understood. We explored the function of the Drosophila ClC‐a chloride channel, since its mammalian ortholog CLCN2 is expressed in glial cells, and defective channel function results in leukodystrophies, which in humans are accompanied by cognitive impairment. We found that ClC‐a was expressed in the niche in cortex glia, which are closely associated with neurogenic tissues. Characterization of loss‐of‐function ClC‐a mutants revealed that these animals had smaller brains and widespread wiring defects. We showed that ClC‐a is required in cortex glia for neurogenesis in neuroepithelia and neuroblasts, and identified defects in a neuroblast lineage that generates guidepost glial cells essential for photoreceptor axon guidance. We propose that glia‐mediated ionic homeostasis could nonautonomously affect neurogenesis, and consequently, the correct assembly of neural circuits.
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Affiliation(s)
- Haritz Plazaola-Sasieta
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Qi Zhu
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Héctor Gaitán-Peñas
- Departament de Ciencies Fisiològiques, Genes, Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Martín Rios
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Raúl Estévez
- Departament de Ciencies Fisiològiques, Genes, Disease and Therapy Program IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Morey
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain.,Institut de Biomedicina de la Universitat de Barcelona (IBUB), Programa de Biologia Integrativa, Barcelona, Spain
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197
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Harnish JM, Deal SL, Chao HT, Wangler MF, Yamamoto S. In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila. J Vis Exp 2019:10.3791/59658. [PMID: 31498321 PMCID: PMC7418855 DOI: 10.3791/59658] [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] [Indexed: 12/13/2022] Open
Abstract
Advances in sequencing technology have made whole-genome and whole-exome datasets more accessible for both clinical diagnosis and cutting-edge human genetics research. Although a number of in silico algorithms have been developed to predict the pathogenicity of variants identified in these datasets, functional studies are critical to determining how specific genomic variants affect protein function, especially for missense variants. In the Undiagnosed Diseases Network (UDN) and other rare disease research consortia, model organisms (MO) including Drosophila, C. elegans, zebrafish, and mice are actively used to assess the function of putative human disease-causing variants. This protocol describes a method for the functional assessment of rare human variants used in the Model Organisms Screening Center Drosophila Core of the UDN. The workflow begins with gathering human and MO information from multiple public databases, using the MARRVEL web resource to assess whether the variant is likely to contribute to a patient's condition as well as design effective experiments based on available knowledge and resources. Next, genetic tools (e.g., T2A-GAL4 and UAS-human cDNA lines) are generated to assess the functions of variants of interest in Drosophila. Upon development of these reagents, two-pronged functional assays based on rescue and overexpression experiments can be performed to assess variant function. In the rescue branch, the endogenous fly genes are "humanized" by replacing the orthologous Drosophila gene with reference or variant human transgenes. In the overexpression branch, the reference and variant human proteins are exogenously driven in a variety of tissues. In both cases, any scorable phenotype (e.g., lethality, eye morphology, electrophysiology) can be used as a read-out, irrespective of the disease of interest. Differences observed between reference and variant alleles suggest a variant-specific effect, and thus likely pathogenicity. This protocol allows rapid, in vivo assessments of putative human disease-causing variants of genes with known and unknown functions.
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Affiliation(s)
- J Michael Harnish
- Department of Molecular and Human Genetics, Baylor College of Medicine
| | - Samantha L Deal
- Program in Developmental Biology, Baylor College of Medicine
| | - Hsiao-Tuan Chao
- Department of Molecular and Human Genetics, Baylor College of Medicine; Department of Pediatrics, Section of Neurology and Developmental Neuroscience, Baylor College of Medicine; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital; Department of Neuroscience, Baylor College of Medicine
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine; Program in Developmental Biology, Baylor College of Medicine; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine; Program in Developmental Biology, Baylor College of Medicine; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital; Department of Neuroscience, Baylor College of Medicine;
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198
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Sato K, Ahsan MT, Ote M, Koganezawa M, Yamamoto D. Calmodulin-binding transcription factor shapes the male courtship song in Drosophila. PLoS Genet 2019; 15:e1008309. [PMID: 31344027 PMCID: PMC6690551 DOI: 10.1371/journal.pgen.1008309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/12/2019] [Accepted: 07/12/2019] [Indexed: 11/18/2022] Open
Abstract
Males of the Drosophila melanogaster mutant croaker (cro) generate a polycyclic pulse song dissimilar to the monocyclic songs typical of wild-type males during courtship. However, cro has not been molecularly mapped to any gene in the genome. We demonstrate that cro is a mutation in the gene encoding the Calmodulin-binding transcription factor (Camta) by genetic complementation tests with chromosomal deficiencies, molecular cloning of genomic fragments that flank the cro-mutagenic P-insertion, and phenotypic rescue of the cro mutant phenotype by Camta+-encoding cDNA as well as a BAC clone containing the gene for Camta. We further show that knockdown of the Camta-encoding gene phenocopies cro mutant songs when targeted to a subset of fruitless-positive neurons that include the mcALa and AL1 clusters in the brain. cro-GAL4 and an anti-Camta antibody labeled a large number of brain neurons including mcALa. We conclude that the Camta-encoding gene represents the cro locus, which has been implicated in a species-specific difference in courtship songs between D. sechellia and simulans. Selecting a suitable mate is a prerequisite for successful breeding in organisms. Indeed, the animals instinctively distinguish a conspecific partner from individuals of other species, yet the mechanism underlying such species-recognition remains largely unknown. In choosing a conspecific male as a mate, fruit fly females rely on a male-derived auditory signal, love song, which is generated by a series of unilateral wing vibration by the male. We study how the males produce love song that is unique to the species. We particularly focus on croaker (cro) mutants, whose males generate distorted love song. Our molecular analysis reveals that the cro mutation inhibits expression of the gene encoding a protein called Calmodulin-binding transcription factor (Camta) and that an introduction of the Camta-encoding DNA into the genome of cro mutants allows the mutant male to sing a normal song. Therefore, the Camta protein is an essential component for love song generation by males. We further show that knockdown of Camta only in tens of specific neurons in the brain is sufficient for inducing the cro mutant phenotype. This study paves the way for unraveling the mechanistic basis for female-male communications in conspecific mating.
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Affiliation(s)
- Kosei Sato
- Neuro-Network Evolution Project, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
| | - Md. Tanveer Ahsan
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Manabu Ote
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Masayuki Koganezawa
- Division of Neurogenetics, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Daisuke Yamamoto
- Neuro-Network Evolution Project, Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, Japan
- * E-mail:
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199
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Letizia A, He D, Astigarraga S, Colombelli J, Hatini V, Llimargas M, Treisman JE. Sidekick Is a Key Component of Tricellular Adherens Junctions that Acts to Resolve Cell Rearrangements. Dev Cell 2019; 50:313-326.e5. [PMID: 31353315 DOI: 10.1016/j.devcel.2019.07.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/03/2019] [Accepted: 07/02/2019] [Indexed: 11/27/2022]
Abstract
Tricellular adherens junctions are points of high tension that are central to the rearrangement of epithelial cells. However, the molecular composition of these junctions is unknown, making it difficult to assess their role in morphogenesis. Here, we show that Sidekick, an immunoglobulin family cell adhesion protein, is highly enriched at tricellular adherens junctions in Drosophila. This localization is modulated by tension, and Sidekick is itself necessary to maintain normal levels of cell bond tension. Loss of Sidekick causes defects in cell and junctional rearrangements in actively remodeling epithelial tissues like the retina and tracheal system. The adaptor proteins Polychaetoid and Canoe are enriched at tricellular adherens junctions in a Sidekick-dependent manner; Sidekick functionally interacts with both proteins and directly binds to Polychaetoid. We suggest that Polychaetoid and Canoe link Sidekick to the actin cytoskeleton to enable tricellular adherens junctions to maintain or transmit cell bond tension during epithelial cell rearrangements.
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Affiliation(s)
- Annalisa Letizia
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain
| | - DanQing He
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Sergio Astigarraga
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Julien Colombelli
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Parc Científic de Barcelona, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Victor Hatini
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, 150 Harrison Avenue, Jaharis 322, Boston, MA 02111, USA
| | - Marta Llimargas
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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Gerlach SU, Sander M, Song S, Herranz H. The miRNA bantam regulates growth and tumorigenesis by repressing the cell cycle regulator tribbles. Life Sci Alliance 2019; 2:2/4/e201900381. [PMID: 31331981 PMCID: PMC6653758 DOI: 10.26508/lsa.201900381] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 12/15/2022] Open
Abstract
This work identifies the cell cycle regulator tribbles as a target of the miRNA bantam involved in the growth regulatory and oncogenic functions of bantam in Drosophila epithelia. One of the fundamental issues in biology is understanding how organ size is controlled. Tissue growth has to be carefully regulated to generate well-functioning organs, and defects in growth control can result in tumor formation. The Hippo signaling pathway is a universal growth regulator and has been implicated in cancer. In Drosophila, the Hippo pathway acts through the miRNA bantam to regulate cell proliferation and apoptosis. Even though the bantam targets regulating apoptosis have been determined, the target genes controlling proliferation have not been identified thus far. In this study, we identify the gene tribbles as a direct bantam target gene. Tribbles limits cell proliferation by suppressing G2/M transition. We show that tribbles regulation by bantam is central in controlling tissue growth and tumorigenesis. We expand our study to other cell cycle regulators and show that deregulated G2/M transition can collaborate with oncogene activation driving tumor formation.
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Affiliation(s)
- Stephan U Gerlach
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Moritz Sander
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Shilin Song
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Héctor Herranz
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
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