1
|
Slater CR. Neuromuscular Transmission in a Biological Context. Compr Physiol 2024; 14:5641-5702. [PMID: 39382166 DOI: 10.1002/cphy.c240001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024]
Abstract
Neuromuscular transmission is the process by which motor neurons activate muscle contraction and thus plays an essential role in generating the purposeful body movements that aid survival. While many features of this process are common throughout the Animal Kingdom, such as the release of transmitter in multimolecular "quanta," and the response to it by opening ligand-gated postsynaptic ion channels, there is also much diversity between and within species. Much of this diversity is associated with specialization for either slow, sustained movements such as maintain posture or fast but brief movements used during escape or prey capture. In invertebrates, with hydrostatic and exoskeletons, most motor neurons evoke graded depolarizations of the muscle which cause graded muscle contractions. By contrast, vertebrate motor neurons trigger action potentials in the muscle fibers which give rise to all-or-none contractions. The properties of neuromuscular transmission, in particular the intensity and persistence of transmitter release, reflect these differences. Neuromuscular transmission varies both between and within individual animals, which often have distinct tonic and phasic subsystems. Adaptive plasticity of neuromuscular transmission, on a range of time scales, occurs in many species. This article describes the main steps in neuromuscular transmission and how they vary in a number of "model" species, including C. elegans , Drosophila , zebrafish, mice, and humans. © 2024 American Physiological Society. Compr Physiol 14:5641-5702, 2024.
Collapse
|
2
|
Pribbenow C, Owald D. Skewing information flow through pre- and postsynaptic plasticity in the mushroom bodies of Drosophila. Learn Mem 2024; 31:a053919. [PMID: 38876487 PMCID: PMC11199954 DOI: 10.1101/lm.053919.124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/26/2024] [Indexed: 06/16/2024]
Abstract
Animal brains need to store information to construct a representation of their environment. Knowledge of what happened in the past allows both vertebrates and invertebrates to predict future outcomes by recalling previous experience. Although invertebrate and vertebrate brains share common principles at the molecular, cellular, and circuit-architectural levels, there are also obvious differences as exemplified by the use of acetylcholine versus glutamate as the considered main excitatory neurotransmitters in the respective central nervous systems. Nonetheless, across central nervous systems, synaptic plasticity is thought to be a main substrate for memory storage. Therefore, how brain circuits and synaptic contacts change following learning is of fundamental interest for understanding brain computations tied to behavior in any animal. Recent progress has been made in understanding such plastic changes following olfactory associative learning in the mushroom bodies (MBs) of Drosophila A current framework of memory-guided behavioral selection is based on the MB skew model, in which antagonistic synaptic pathways are selectively changed in strength. Here, we review insights into plasticity at dedicated Drosophila MB output pathways and update what is known about the plasticity of both pre- and postsynaptic compartments of Drosophila MB neurons.
Collapse
Affiliation(s)
- Carlotta Pribbenow
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - David Owald
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Einstein Center for Neurosciences Berlin, 10117 Berlin, Germany
- NeuroCure, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| |
Collapse
|
3
|
von Saucken VE, Windner SE, Baylies MK. Postsynaptic BMP signaling regulates myonuclear properties in Drosophila larval muscles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588944. [PMID: 38645063 PMCID: PMC11030338 DOI: 10.1101/2024.04.10.588944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The syncytial mammalian muscle fiber contains a heterogeneous population of (myo)nuclei. At the neuromuscular junction (NMJ), myonuclei have specialized positioning and gene expression. However, it remains unclear how myonuclei are recruited and what regulates myonuclear output at the NMJ. Here, we identify specific properties of myonuclei located near the Drosophila larval NMJ. These synaptic myonuclei have increased size in relation to their surrounding cytoplasmic domain (scaling), increased DNA content (ploidy), and increased levels of transcription factor pMad, a readout for BMP signaling activity. Our genetic manipulations show local BMP signaling affects muscle size, nuclear size, ploidy, and NMJ size and function. In support, RNA sequencing analysis reveals that pMad regulates genes involved in muscle growth, ploidy (i.e., E2f1), and neurotransmission. Our data suggest that muscle BMP signaling instructs synaptic myonuclear output that then positively shapes the NMJ synapse. This study deepens our understanding of how myonuclear heterogeneity supports local signaling demands to fine tune cellular function and NMJ activity.
Collapse
Affiliation(s)
- Victoria E. von Saucken
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
- Weill Cornell-Rockefeller-Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065 USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065 USA
| | - Stefanie E. Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
| | - Mary K. Baylies
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065 USA
| |
Collapse
|
4
|
Mocci I, Casu MA, Sogos V, Liscia A, Angius R, Cadeddu F, Fanti M, Muroni P, Talani G, Diana A, Collu M, Setzu MD. Effects of memantine on mania-like phenotypes exhibited by Drosophila Shaker mutants. CNS Neurosci Ther 2023. [PMID: 36942502 DOI: 10.1111/cns.14145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 03/23/2023] Open
Abstract
INTRODUCTION Increased glutamate levels and electrolytic fluctuations have been observed in acutely manic patients. Despite some efficacy of the non-competitive NMDA receptor antagonist memantine (Mem), such as antidepressant-like and mood-stabilizer drugs in clinical studies, its specific mechanisms of action are still uncertain. The present study aims to better characterize the Drosophila melanogaster fly Shaker mutants (SH), as a translational model of manic episodes within bipolar disorder in humans, and to investigate the potential anti-manic properties of Mem. METHODS AND RESULTS Our findings showed typical behavioral abnormalities in SH, which mirrored with the overexpression of NMDAR-NR1 protein subunit, matched well to glutamate up-regulation. Such molecular features were associated to a significant reduction of SH brain volume in comparison to Wild Type strain flies (WT). Here we report on the ability of Mem treatment to ameliorate behavioral aberrations of SH (similar to that of Lithium), and its ability to reduce NMDAR-NR1 over-expression. CONCLUSIONS Our results show the involvement of the glutamatergic system in the SH, given the interaction between the Shaker channel and the NMDA receptor, suggesting this model as a promising tool for studying the neurobiology of bipolar disorders. Moreover, our results show Mem as a potential disease-modifying therapy, providing insight on new mechanisms of action.
Collapse
Affiliation(s)
- Ignazia Mocci
- Institute of Translational Pharmacology, National Research Council, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Maria Antonietta Casu
- Institute of Translational Pharmacology, National Research Council, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Valeria Sogos
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Anna Liscia
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Rossella Angius
- Unit of Biomedical Research Support, NMR Laboratory and Bioanalytical Technologies, Sardegna Ricerche, Science and Technology Park of Sardinia, Cagliari, Italy
| | - Francesca Cadeddu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maura Fanti
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Patrizia Muroni
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Giuseppe Talani
- Institute of Neuroscience, National Research Council, Monserrato, Italy
| | - Andrea Diana
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maria Collu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Maria Dolores Setzu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| |
Collapse
|
5
|
Vicidomini R, Serpe M. Local BMP signaling: A sensor for synaptic activity that balances synapse growth and function. Curr Top Dev Biol 2022; 150:211-254. [PMID: 35817503 PMCID: PMC11102767 DOI: 10.1016/bs.ctdb.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Synapse development is coordinated by intercellular communication between the pre- and postsynaptic compartments, and by neuronal activity itself. In flies as in vertebrates, neuronal activity induces input-specific changes in the synaptic strength so that the entire circuit maintains stable function in the face of many challenges, including changes in synapse number and strength. But how do neurons sense synapse activity? In several studies carried out using the Drosophila neuromuscular junction (NMJ), we demonstrated that local BMP signaling provides an exquisite sensor for synapse activity. Here we review the main features of this exquisite sensor and discuss its functioning beyond monitoring the synapse activity but rather as a key controller that operates in coordination with other BMP signaling pathways to balance synapse growth, maturation and function.
Collapse
Affiliation(s)
- Rosario Vicidomini
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Mihaela Serpe
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States.
| |
Collapse
|
6
|
Park J, Kang GH, Kim Y, Lee JY, Song JA, Hwang JH. Formaldehyde exposure induces differentiation of regulatory T cells via the NFAT-mediated T cell receptor signalling pathway in Yucatan minipigs. Sci Rep 2022; 12:8149. [PMID: 35581361 PMCID: PMC9114421 DOI: 10.1038/s41598-022-12183-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 05/05/2022] [Indexed: 12/31/2022] Open
Abstract
The use of minipigs (Sus scrofa) as a platform for toxicological and pharmacological research is well established. In the present study, we investigated the effect of formaldehyde (FA) exposure on helper T cell-mediated splenic immune responses in Yucatan minipigs. The minipigs were exposed to different inhaled concentrations of FA (0, 2.16, 4.62, or 10.48 mg/m3) for a period of 2 weeks. Immune responses elicited by exposure to FA were determined by assessing physiological parameters, mRNA expression, and cytokine production. Additionally, the distribution of helper T cells and regulatory T (Treg) cells and expression of NFAT families, which are well-known T cell receptor signalling proteins associated with regulatory T cell development, were evaluated. Exposure to FA suppressed the expression of genes associated with Th1 and Th2 cells in minipigs in a concentration-dependent manner. The subsequent production of cytokines also declined post-FA exposure. Furthermore, exposure to FA induced the differentiation of CD4+ Foxp3+ Treg cells with divergent expression levels of NFAT1 and NFAT2. These results indicated that exposure to FA increased the Treg cell population via the NFAT-mediated T cell receptor signalling pathway, leading to suppression of effector T cell activity with a decline in T cell-related cytokine production.
Collapse
Affiliation(s)
- Jeongsik Park
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea
| | - Goo-Hwa Kang
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea
| | - Youngkyu Kim
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea.,Department of Stem Cell and Regenerative Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul-si, 27447, Republic of Korea
| | - Ju Young Lee
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea.,Department of Human and Environmental Toxicology, University of Science & Technology, Daejeon, 34113, Republic of Korea
| | - Jeong Ah Song
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea
| | - Jeong Ho Hwang
- Animal Model Research Group, Jeonbuk Department of Inhalation Research, Korea Institute of Toxicology, 30 Baehak 1-gil, Jeonguep, Jeollabuk-do, 56212, Republic of Korea.
| |
Collapse
|
7
|
Aponte-Santiago NA, Littleton JT. Synaptic Properties and Plasticity Mechanisms of Invertebrate Tonic and Phasic Neurons. Front Physiol 2020; 11:611982. [PMID: 33391026 PMCID: PMC7772194 DOI: 10.3389/fphys.2020.611982] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022] Open
Abstract
Defining neuronal cell types and their associated biophysical and synaptic diversity has become an important goal in neuroscience as a mechanism to create comprehensive brain cell atlases in the post-genomic age. Beyond broad classification such as neurotransmitter expression, interneuron vs. pyramidal, sensory or motor, the field is still in the early stages of understanding closely related cell types. In both vertebrate and invertebrate nervous systems, one well-described distinction related to firing characteristics and synaptic release properties are tonic and phasic neuronal subtypes. In vertebrates, these classes were defined based on sustained firing responses during stimulation (tonic) vs. transient responses that rapidly adapt (phasic). In crustaceans, the distinction expanded to include synaptic release properties, with tonic motoneurons displaying sustained firing and weaker synapses that undergo short-term facilitation to maintain muscle contraction and posture. In contrast, phasic motoneurons with stronger synapses showed rapid depression and were recruited for short bursts during fast locomotion. Tonic and phasic motoneurons with similarities to those in crustaceans have been characterized in Drosophila, allowing the genetic toolkit associated with this model to be used for dissecting the unique properties and plasticity mechanisms for these neuronal subtypes. This review outlines general properties of invertebrate tonic and phasic motoneurons and highlights recent advances that characterize distinct synaptic and plasticity pathways associated with two closely related glutamatergic neuronal cell types that drive invertebrate locomotion.
Collapse
Affiliation(s)
- Nicole A. Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - J. Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| |
Collapse
|
8
|
Zhao K, Hong H, Zhao L, Huang S, Gao Y, Metwally E, Jiang Y, Sigrist SJ, Zhang YQ. Postsynaptic cAMP signalling regulates the antagonistic balance of Drosophila glutamate receptor subtypes. Development 2020; 147:226061. [PMID: 33234716 PMCID: PMC7758632 DOI: 10.1242/dev.191874] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 11/13/2020] [Indexed: 12/19/2022]
Abstract
The balance among different subtypes of glutamate receptors (GluRs) is crucial for synaptic function and plasticity at excitatory synapses. However, the mechanisms balancing synaptic GluR subtypes remain unclear. Herein, we show that the two subtypes of GluRs (A and B) expressed at Drosophila neuromuscular junction synapses mutually antagonize each other in terms of their relative synaptic levels and affect subsynaptic localization of each other, as shown by super-resolution microscopy. Upon temperature shift-induced neuromuscular junction plasticity, GluR subtype A increased but subtype B decreased with a timecourse of hours. Inhibition of the activity of GluR subtype A led to imbalance of GluR subtypes towards more GluRIIA. To gain a better understanding of the signalling pathways underlying the balance of GluR subtypes, we performed an RNA interference screen of candidate genes and found that postsynaptic-specific knockdown of dunce, which encodes cAMP phosphodiesterase, increased levels of GluR subtype A but decreased subtype B. Furthermore, bidirectional alterations of postsynaptic cAMP signalling resulted in the same antagonistic regulation of the two GluR subtypes. Our findings thus identify a direct role of postsynaptic cAMP signalling in control of the plasticity-related balance of GluRs. Summary: The antagonistic balance of GluR subtypes, which is associated with synaptic plasticity, is regulated by cAMP signalling in postsynaptic muscles of Drosophila NMJ synapses.
Collapse
Affiliation(s)
- Kai Zhao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Huilin Hong
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lu Zhao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Sheng Huang
- Freie Universität Berlin, Institute for Biology/Genetics, Takustrasse 6, 14195 Berlin, Germany
| | - Ying Gao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Elsayed Metwally
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuqiang Jiang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Stephan J Sigrist
- Freie Universität Berlin, Institute for Biology/Genetics, Takustrasse 6, 14195 Berlin, Germany.,NeuroCure, Charite, Chariteplatz 1, 10117 Berlin, Germany
| | - Yong Q Zhang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
9
|
Agudelo A, St Amand V, Grissom L, Lafond D, Achilli T, Sahin A, Reenan R, Stilwell G. Age-dependent degeneration of an identified adult leg motor neuron in a Drosophila SOD1 model of ALS. Biol Open 2020; 9:bio049692. [PMID: 32994185 PMCID: PMC7595701 DOI: 10.1242/bio.049692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 09/21/2020] [Indexed: 12/31/2022] Open
Abstract
Mutations in superoxide dismutase 1 (SOD1) cause familial amyotrophic lateral sclerosis (ALS) in humans. ALS is a neurodegenerative disease characterized by progressive motor neuron loss leading to paralysis and inevitable death in affected individuals. Using a gene replacement strategy to introduce disease mutations into the orthologous Drosophila sod1 (dsod1) gene, here, we characterize changes at the neuromuscular junction using longer-lived dsod1 mutant adults. Homozygous dsod1H71Y/H71Y or dsod1null/null flies display progressive walking defects with paralysis of the third metathoracic leg. In dissected legs, we assessed age-dependent changes in a single identified motor neuron (MN-I2) innervating the tibia levitator muscle. At adult eclosion, MN-I2 of dsod1H71Y/H71Y or sod1null/null flies is patterned similar to wild-type flies indicating no readily apparent developmental defects. Over the course of 10 days post-eclosion, MN-I2 shows an overall reduction in arborization with bouton swelling and loss of the post-synaptic marker discs-large (dlg) in mutant dsod1 adults. In addition, increases in polyubiquitinated proteins correlate with the timing and extent of MN-I2 changes. Because similar phenotypes are observed between flies homozygous for either dsod1H71Y or dsod1null alleles, we conclude these NMJ changes are mainly associated with sod loss-of-function. Together these studies characterize age-related morphological and molecular changes associated with axonal retraction in a Drosophila model of ALS that recapitulate an important aspect of the human disease.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Anthony Agudelo
- Department of Biology, Rhode Island College, 600 Mt. Pleasant Ave., Providence, RI, 02908 USA
| | - Victoria St Amand
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, 02912 USA
| | - Lindsey Grissom
- Department of Biology, Rhode Island College, 600 Mt. Pleasant Ave., Providence, RI, 02908 USA
| | - Danielle Lafond
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, 02912 USA
| | - Toni Achilli
- Department of Biology, Rhode Island College, 600 Mt. Pleasant Ave., Providence, RI, 02908 USA
| | - Asli Sahin
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, 02912 USA
| | - Robert Reenan
- Department of Molecular Biology, Cell Biology & Biochemistry, Brown University, Providence, RI, 02912 USA
| | - Geoff Stilwell
- Department of Biology, Rhode Island College, 600 Mt. Pleasant Ave., Providence, RI, 02908 USA
| |
Collapse
|
10
|
Patel PH, Wilkinson EC, Starke EL, McGimsey MR, Blankenship JT, Barbee SA. Vps54 regulates Drosophila neuromuscular junction development and interacts genetically with Rab7 to control composition of the postsynaptic density. Biol Open 2020; 9:bio053421. [PMID: 32747448 PMCID: PMC7473652 DOI: 10.1242/bio.053421] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/22/2020] [Indexed: 01/04/2023] Open
Abstract
Vps54 is a subunit of the Golgi-associated retrograde protein (GARP) complex, which is involved in tethering endosome-derived vesicles to the trans-Golgi network (TGN). In the wobbler mouse, a model for human motor neuron (MN) disease, reduction in the levels of Vps54 causes neurodegeneration. However, it is unclear how disruption of the GARP complex leads to MN dysfunction. To better understand the role of Vps54 in MNs, we have disrupted expression of the Vps54 ortholog in Drosophila and examined the impact on the larval neuromuscular junction (NMJ). Surprisingly, we show that both null mutants and MN-specific knockdown of Vps54 leads to NMJ overgrowth. Reduction of Vps54 partially disrupts localization of the t-SNARE, Syntaxin-16, to the TGN but has no visible impact on endosomal pools. MN-specific knockdown of Vps54 in MNs combined with overexpression of the small GTPases Rab5, Rab7, or Rab11 suppresses the Vps54 NMJ phenotype. Conversely, knockdown of Vps54 combined with overexpression of dominant negative Rab7 causes NMJ and behavioral abnormalities including a decrease in postsynaptic Dlg and GluRIIB levels without any effect on GluRIIA. Taken together, these data suggest that Vps54 controls larval MN axon development and postsynaptic density composition through a mechanism that requires Rab7.
Collapse
Affiliation(s)
- Prajal H Patel
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Emily C Wilkinson
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Emily L Starke
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - Malea R McGimsey
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
| | - J Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
- Molecular and Cellular Biophysics Program, University of Denver, Denver, CO 80210, USA
| | - Scott A Barbee
- Department of Biological Sciences, University of Denver, Denver, CO 80210, USA
- Molecular and Cellular Biophysics Program, University of Denver, Denver, CO 80210, USA
| |
Collapse
|
11
|
Chou VT, Johnson SA, Van Vactor D. Synapse development and maturation at the drosophila neuromuscular junction. Neural Dev 2020; 15:11. [PMID: 32741370 PMCID: PMC7397595 DOI: 10.1186/s13064-020-00147-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022] Open
Abstract
Synapses are the sites of neuron-to-neuron communication and form the basis of the neural circuits that underlie all animal cognition and behavior. Chemical synapses are specialized asymmetric junctions between a presynaptic neuron and a postsynaptic target that form through a series of diverse cellular and subcellular events under the control of complex signaling networks. Once established, the synapse facilitates neurotransmission by mediating the organization and fusion of synaptic vesicles and must also retain the ability to undergo plastic changes. In recent years, synaptic genes have been implicated in a wide array of neurodevelopmental disorders; the individual and societal burdens imposed by these disorders, as well as the lack of effective therapies, motivates continued work on fundamental synapse biology. The properties and functions of the nervous system are remarkably conserved across animal phyla, and many insights into the synapses of the vertebrate central nervous system have been derived from studies of invertebrate models. A prominent model synapse is the Drosophila melanogaster larval neuromuscular junction, which bears striking similarities to the glutamatergic synapses of the vertebrate brain and spine; further advantages include the simplicity and experimental versatility of the fly, as well as its century-long history as a model organism. Here, we survey findings on the major events in synaptogenesis, including target specification, morphogenesis, and the assembly and maturation of synaptic specializations, with a emphasis on work conducted at the Drosophila neuromuscular junction.
Collapse
Affiliation(s)
- Vivian T Chou
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Seth A Johnson
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA.
| | - David Van Vactor
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA.
| |
Collapse
|
12
|
Poovathumkadavil P, Jagla K. Genetic Control of Muscle Diversification and Homeostasis: Insights from Drosophila. Cells 2020; 9:cells9061543. [PMID: 32630420 PMCID: PMC7349286 DOI: 10.3390/cells9061543] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/19/2020] [Accepted: 06/23/2020] [Indexed: 12/13/2022] Open
Abstract
In the fruit fly, Drosophila melanogaster, the larval somatic muscles or the adult thoracic flight and leg muscles are the major voluntary locomotory organs. They share several developmental and structural similarities with vertebrate skeletal muscles. To ensure appropriate activity levels for their functions such as hatching in the embryo, crawling in the larva, and jumping and flying in adult flies all muscle components need to be maintained in a functionally stable or homeostatic state despite constant strain. This requires that the muscles develop in a coordinated manner with appropriate connections to other cell types they communicate with. Various signaling pathways as well as extrinsic and intrinsic factors are known to play a role during Drosophila muscle development, diversification, and homeostasis. In this review, we discuss genetic control mechanisms of muscle contraction, development, and homeostasis with particular emphasis on the contractile unit of the muscle, the sarcomere.
Collapse
|
13
|
Genetic Dissection of Alzheimer's Disease Using Drosophila Models. Int J Mol Sci 2020; 21:ijms21030884. [PMID: 32019113 PMCID: PMC7037931 DOI: 10.3390/ijms21030884] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/26/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD), a main cause of dementia, is the most common neurodegenerative disease that is related to abnormal accumulation of the amyloid β (Aβ) protein. Despite decades of intensive research, the mechanisms underlying AD remain elusive, and the only available treatment remains symptomatic. Molecular understanding of the pathogenesis and progression of AD is necessary to develop disease-modifying treatment. Drosophila, as the most advanced genetic model, has been used to explore the molecular mechanisms of AD in the last few decades. Here, we introduce Drosophila AD models based on human Aβ and summarize the results of their genetic dissection. We also discuss the utility of functional genomics using the Drosophila system in the search for AD-associated molecular mechanisms in the post-genomic era.
Collapse
|
14
|
Sakharkar MK, Kashmir Singh SK, Rajamanickam K, Mohamed Essa M, Yang J, Chidambaram SB. A systems biology approach towards the identification of candidate therapeutic genes and potential biomarkers for Parkinson's disease. PLoS One 2019; 14:e0220995. [PMID: 31487305 PMCID: PMC6728017 DOI: 10.1371/journal.pone.0220995] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 07/26/2019] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease (PD) is an irreversible and incurable multigenic neurodegenerative disorder. It involves progressive loss of mid brain dopaminergic neurons in the substantia nigra pars compacta (SN). We compared brain gene expression profiles with those from the peripheral blood cells of a separate sample of PD patients to identify disease-associated genes. Here, we demonstrate the use of gene expression profiling of brain and blood for detecting valid targets and identifying early PD biomarkers. Implementing this systematic approach, we discovered putative PD risk genes in brain, delineated biological processes and molecular functions that may be particularly disrupted in PD and also identified several putative PD biomarkers in blood. 20 of the differentially expressed genes in SN were also found to be differentially expressed in the blood. Further application of this methodology to other brain regions and neurological disorders should facilitate the discovery of highly reliable and reproducible candidate risk genes and biomarkers for PD. The identification of valid peripheral biomarkers for PD may ultimately facilitate early identification, intervention, and prevention efforts as well.
Collapse
Affiliation(s)
- Meena Kishore Sakharkar
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
- * E-mail: (MKS); (SBC)
| | | | - Karthic Rajamanickam
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
| | | | - Jian Yang
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Canada
| | - Saravana Babu Chidambaram
- Department of Pharmacology, JSS College of Pharmacy, JSSAHER, Karnataka, India
- * E-mail: (MKS); (SBC)
| |
Collapse
|
15
|
Syed A, Lukacsovich T, Pomeroy M, Bardwell AJ, Decker GT, Waymire KG, Purcell J, Huang W, Gui J, Padilla EM, Park C, Paul A, Pham TBT, Rodriguez Y, Wei S, Worthge S, Zebarjedi R, Zhang B, Bardwell L, Marsh JL, MacGregor GR. Miles to go (mtgo) encodes FNDC3 proteins that interact with the chaperonin subunit CCT3 and are required for NMJ branching and growth in Drosophila. Dev Biol 2018; 445:37-53. [PMID: 30539716 DOI: 10.1016/j.ydbio.2018.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 09/01/2018] [Accepted: 10/17/2018] [Indexed: 11/17/2022]
Abstract
Analysis of mutants that affect formation and function of the Drosophila larval neuromuscular junction (NMJ) has provided valuable insight into genes required for neuronal branching and synaptic growth. We report that NMJ development in Drosophila requires both the Drosophila ortholog of FNDC3 genes; CG42389 (herein referred to as miles to go; mtgo), and CCT3, which encodes a chaperonin complex subunit. Loss of mtgo function causes late pupal lethality with most animals unable to escape the pupal case, while rare escapers exhibit an ataxic gait and reduced lifespan. NMJs in mtgo mutant larvae have dramatically reduced branching and growth and fewer synaptic boutons compared with control animals. Mutant larvae show normal locomotion but display an abnormal self-righting response and chemosensory deficits that suggest additional functions of mtgo within the nervous system. The pharate lethality in mtgo mutants can be rescued by both low-level pan- and neuronal-, but not muscle-specific expression of a mtgo transgene, supporting a neuronal-intrinsic requirement for mtgo in NMJ development. Mtgo encodes three similar proteins whose domain structure is most closely related to the vertebrate intracellular cytosolic membrane-anchored fibronectin type-III domain-containing protein 3 (FNDC3) protein family. Mtgo physically and genetically interacts with Drosophila CCT3, which encodes a subunit of the TRiC/CCT chaperonin complex required for maturation of actin, tubulin and other substrates. Drosophila larvae heterozygous for a mutation in CCT3 that reduces binding between CCT3 and MTGO also show abnormal NMJ development similar to that observed in mtgo null mutants. Hence, the intracellular FNDC3-ortholog MTGO and CCT3 can form a macromolecular complex, and are both required for NMJ development in Drosophila.
Collapse
Affiliation(s)
- Adeela Syed
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Tamás Lukacsovich
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Miles Pomeroy
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - A Jane Bardwell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Gentry Thomas Decker
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA
| | - Katrina G Waymire
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Judith Purcell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Weijian Huang
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - James Gui
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Emily M Padilla
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Cindy Park
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Antor Paul
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Thai Bin T Pham
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Yanete Rodriguez
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Stephen Wei
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Shane Worthge
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Ronak Zebarjedi
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA
| | - Lee Bardwell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - J Lawrence Marsh
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA.
| | - Grant R MacGregor
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA.
| |
Collapse
|
16
|
Akbergenova Y, Cunningham KL, Zhang YV, Weiss S, Littleton JT. Characterization of developmental and molecular factors underlying release heterogeneity at Drosophila synapses. eLife 2018; 7:38268. [PMID: 29989549 PMCID: PMC6075867 DOI: 10.7554/elife.38268] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/30/2018] [Indexed: 12/14/2022] Open
Abstract
Neurons communicate through neurotransmitter release at specialized synaptic regions known as active zones (AZs). Using biosensors to visualize single synaptic vesicle fusion events at Drosophila neuromuscular junctions, we analyzed the developmental and molecular determinants of release probability (Pr) for a defined connection with ~300 AZs. Pr was heterogeneous but represented a stable feature of each AZ. Pr remained stable during high frequency stimulation and retained heterogeneity in mutants lacking the Ca2+ sensor Synaptotagmin 1. Pr correlated with both presynaptic Ca2+ channel abundance and Ca2+ influx at individual release sites. Pr heterogeneity also correlated with glutamate receptor abundance, with high Pr connections developing receptor subtype segregation. Intravital imaging throughout development revealed that AZs acquire high Pr during a multi-day maturation period, with Pr heterogeneity largely reflecting AZ age. The rate of synapse maturation was activity-dependent, as both increases and decreases in neuronal activity modulated glutamate receptor field size and segregation. To send a message to its neighbor, a neuron releases chemicals called neurotransmitters into the gap – or synapse – between them. The neurotransmitter molecules bind to proteins on the receiver neuron called receptors. But what causes the sender neuron to release neurotransmitter in the first place? The process starts when an electrical impulse called an action potential arrives at the sender cell. Its arrival causes channels in the membrane of the sender neuron to open, so that calcium ions flood into the cell. The calcium ions interact with packages of neurotransmitter molecules, known as synaptic vesicles. This causes some of the vesicles to empty their contents into the synapse. But this process is not particularly reliable. Only a small fraction of action potentials cause vesicles to fuse with the synaptic membrane. How likely this is to occur varies greatly between neurons, and even between synapses formed by the same neuron. Synapses that are likely to release neurotransmitter are said to be strong. They are good at passing messages from the sender neuron to the receiver. Synapses with a low probability of release are said to be weak. But what exactly differs between strong and weak synapses? Akbergenova et al. studied synapses between motor neurons and muscle cells in the fruit fly Drosophila. Each motor neuron forms several hundred synapses. Some of these synapses are 50 times more likely to release neurotransmitter than others. Using calcium imaging and genetics, Akbergenova et al. showed that sender cells at strong synapses have more calcium channels than sender cells at weak synapses. The subtypes and arrangement of receptor proteins also differ between the receiver neurons of strong versus weak synapses. Finally, studies in larvae revealed that newly formed synapses all start out weak and then gradually become stronger. How fast this strengthening occurs depends on how active the neuron at the synapse is. This study has shown, in unprecedented detail, key molecular factors that make some fruit fly synapses more likely to release neurotransmitter than others. Many proteins at synapses of mammals resemble those at fruit fly synapses. This means that similar factors may also explain differences in synaptic strength in the mammalian brain. Changes in the strength of synapses underlie the ability to learn. Furthermore, many neurological and psychiatric disorders result from disruption of synapses. Understanding the molecular basis of synapses will thus provide clues to the origins of certain brain diseases.
Collapse
Affiliation(s)
- Yulia Akbergenova
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Yao V Zhang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Shirley Weiss
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| |
Collapse
|
17
|
Critical role for Annexin A7 in secondary brain injury mediated by its phosphorylation after experimental intracerebral hemorrhage in rats. Neurobiol Dis 2018; 110:82-92. [DOI: 10.1016/j.nbd.2017.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/14/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023] Open
|
18
|
Gan G, Zhang C. The precise subcellular localization of Dlg in the Drosophila larva body wall using improved pre-embedding immuno-EM. J Neurosci Res 2017; 96:467-480. [PMID: 29231975 DOI: 10.1002/jnr.24139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Revised: 07/12/2017] [Accepted: 07/21/2017] [Indexed: 12/21/2022]
Abstract
Discs-large (Dlg) plays important roles in nerve tissue and epithelial tissue in Drosophila. However, the precise positioning of Dlg in the neuromuscular junction remains to be confirmed using an optimized labeling method. In this study, we improved the method of pre-embedding immunogold electron microscopy without the osmic tetroxide procedure, and we found that Lowicryl K4 M resin and low temperature helped to preserve the authenticity of the labeling signal with relatively good contrast. Dlg was strongly expressed in the entire subsynaptic reticulum (SSR) membrane of type Ib boutons, expressed in parts of the SSR membrane of type Is boutons, weakly expressed in axon terminals and axons, and not expressed in pre- or postsynaptic membranes of type Is boutons. In muscle cells and stratum corneum cells, Dlg was expressed both in the cytoplasm and in organelles with biomembranes. The precise location of Dlg in SSR membranes, rather than in postsynaptic membranes, shows that Dlg, with its multiple domains, acts as a remote or indirect regulator in postsynaptic signal transduction.
Collapse
Affiliation(s)
- Guangming Gan
- Medical School Southeast University, Nanjing, China.,Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Southeast University, Nanjing, China
| | - Chenchen Zhang
- Medical School Southeast University, Nanjing, China.,Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Southeast University, Nanjing, China
| |
Collapse
|
19
|
SAP97 Binding Partner CRIPT Promotes Dendrite Growth In Vitro and In Vivo. eNeuro 2017; 4:eN-NWR-0175-17. [PMID: 29218323 PMCID: PMC5718245 DOI: 10.1523/eneuro.0175-17.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 10/30/2017] [Accepted: 10/30/2017] [Indexed: 01/15/2023] Open
Abstract
The dendritic tree is a key determinant of neuronal information processing. In the motor system, the dendritic tree of spinal cord neurons undergoes dramatic remodeling in an activity-dependent manner during early postnatal life. This leads to the proper segmental spinal cord connectivity that subserves normal locomotor behavior. One molecular system driving the establishment of dendrite architecture of mammalian motor neurons relies on AMPA receptors (AMPA-Rs) assembled with the GluA1 subunit, and this occurs in an NMDA receptor (NMDA-R)-independent manner. The dendrite growth promoting activity of GluA1-containing AMPA-Rs depends on its intracellular binding partner, SAP97, and SAP97's PDZ3 domain. We show here that cysteine-rich interactor of PDZ3 (CRIPT) is a bona fide SAP97 PDZ3-domain binding partner, localizes to synapses with GluA1 and SAP97 along the dendritic tree, and is a determinant of the dendritic growth of mammalian spinal cord neurons. We further show that CRIPT has a well-conserved ortholog in the nematode, Caenorhabditis elegans, and animals lacking CRIPT display decreased dendrite branching of the well-studied PVD neuron in vivo. The lack of CRIPT leads to a selective defect in touch perception, and this is rescued by expression of wild-type (WT) human CRIPT (hCRIPT) in the nervous system. This work brings new light into the molecular machinery that drives dendritic growth during development and may prove relevant to the promotion of nervous system plasticity following insult.
Collapse
|
20
|
Dilla-Ermita CJ, Tandayu E, Juanillas VM, Detras J, Lozada DN, Dwiyanti MS, Vera Cruz C, Mbanjo EGN, Ardales E, Diaz MG, Mendioro M, Thomson MJ, Kretzschmar T. Genome-wide Association Analysis Tracks Bacterial Leaf Blight Resistance Loci In Rice Diverse Germplasm. RICE (NEW YORK, N.Y.) 2017; 10:8. [PMID: 28321828 PMCID: PMC5359197 DOI: 10.1186/s12284-017-0147-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/23/2017] [Indexed: 05/19/2023]
Abstract
BACKGROUND A range of resistance loci against different races of Xanthomonas oryzae pv. oryzae (Xoo), the pathogen causing bacterial blight (BB) disease of rice, have been discovered and characterized. Several have been deployed in modern varieties, however, due to rapid evolution of Xoo, a number have already become ineffective. The continuous "arms race" between Xoo and rice makes it imperative to discover new resistance loci to enable durable deployment of multiple resistance genes in modern breeding lines. Rice diversity panels can be exploited as reservoirs of useful genetic variation for bacterial blight (BB) resistance. This study was conducted to identify loci associated to BB resistance, new genetic donors and useful molecular markers for marker-assisted breeding. RESULTS A genome-wide association study (GWAS) of BB resistance using a diverse panel of 285 rice accessions was performed to identify loci that are associated with resistance to nine Xoo strains from the Philippines, representative of eight global races. Single nucleotide polymorphisms (SNPs) associated with differential resistance were identified in the diverse panel and a subset of 198 indica accessions. Strong associations were found for novel SNPs linked with known bacterial blight resistance Xa genes, from which high utility markers for tracking and selection of resistance genes in breeding programs were designed. Furthermore, significant associations of SNPs in chromosomes 6, 9, 11, and 12 did not overlap with known resistance loci and hence might prove to be novel sources of resistance. Detailed analysis revealed haplotypes that correlated with resistance and analysis of putative resistance alleles identified resistant genotypes as potential donors of new resistance genes. CONCLUSIONS The results of the GWAS validated known genes underlying resistance and identified novel loci that provide useful targets for further investigation. SNP markers and genetic donors identified in this study will help plant breeders in improving and diversifying resistance to BB.
Collapse
Affiliation(s)
- Christine Jade Dilla-Ermita
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Erwin Tandayu
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Venice Margarette Juanillas
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Jeffrey Detras
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Dennis Nicuh Lozada
- Crop, Soil, and Environmental Science, University of Arkansas, Fayettevile, AR, USA
| | - Maria Stefanie Dwiyanti
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Casiana Vera Cruz
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Edwige Gaby Nkouaya Mbanjo
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Edna Ardales
- Crop Protection Cluster, University of the Philippines Los Baños, College, Laguna, Philippines
| | - Maria Genaleen Diaz
- Institute of Biological Sciences, University of the Philippines Los Baños, College, Laguna, Philippines
| | - Merlyn Mendioro
- Institute of Biological Sciences, University of the Philippines Los Baños, College, Laguna, Philippines
| | - Michael J Thomson
- Department of Soil and Crop Sciences, Texas A&M University, College Station, TX, USA
| | - Tobias Kretzschmar
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Laguna, Philippines.
| |
Collapse
|
21
|
Wu CH, Giampetruzzi A, Tran H, Fallini C, Gao FB, Landers JE. A Drosophila model of ALS reveals a partial loss of function of causative human PFN1 mutants. Hum Mol Genet 2017; 26:2146-2155. [PMID: 28379367 DOI: 10.1093/hmg/ddx112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/16/2017] [Indexed: 01/04/2023] Open
Abstract
Mutations in the profilin 1 (PFN1) gene are causative for familial amyotrophic lateral sclerosis (fALS). However, it is still not fully understood how these mutations lead to neurodegeneration. To address this question, we generated a novel Drosophila model expressing human wild-type and ALS-causative PFN1 mutants. We show that at larval neuromuscular junctions (NMJ), motor neuron expression of wild-type human PFN1 increases the number of ghost boutons, active zone density, F-actin content, and the formation of filopodia. In contrast, the expression of ALS-causative human PFN1 mutants causes a less pronounced phenotype, suggesting a loss of function of these mutants in promoting NMJ remodeling. Importantly, expression of human PFN1 in motor neurons results in progressive locomotion defects and shorter lifespan in adult flies, while ALS-causative PFN1 mutants display a less toxic effect. In summary, our study provides evidence that PFN1 is important in regulating NMJ morphology and influences survival and locomotion in Drosophila. Furthermore, our results suggest ALS-causative human PFN1 mutants display a partial loss of function relative to wild-type hPFN1 that may contribute to human disease pathogenesis.
Collapse
Affiliation(s)
- Chi-Hong Wu
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Anthony Giampetruzzi
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Helene Tran
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Claudia Fallini
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John E Landers
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| |
Collapse
|
22
|
Berry KP, Nedivi E. Spine Dynamics: Are They All the Same? Neuron 2017; 96:43-55. [PMID: 28957675 DOI: 10.1016/j.neuron.2017.08.008] [Citation(s) in RCA: 314] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 05/03/2017] [Accepted: 08/04/2017] [Indexed: 11/19/2022]
Abstract
Since Cajal's first drawings of Golgi stained neurons, generations of researchers have been fascinated by the small protrusions, termed spines, studding many neuronal dendrites. Most excitatory synapses in the mammalian CNS are located on dendritic spines, making spines convenient proxies for excitatory synaptic presence. When in vivo imaging revealed that dendritic spines are dynamic structures, their addition and elimination were interpreted as excitatory synapse gain and loss, respectively. Spine imaging has since become a popular assay for excitatory circuit remodeling. In this review, we re-evaluate the validity of using spine dynamics as a straightforward reflection of circuit rewiring. Recent studies tracking both spines and synaptic markers in vivo reveal that 20% of spines lack PSD-95 and are short lived. Although they account for most spine dynamics, their remodeling is unlikely to impact long-term network structure. We discuss distinct roles that spine dynamics can play in circuit remodeling depending on synaptic content.
Collapse
Affiliation(s)
- Kalen P Berry
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Elly Nedivi
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| |
Collapse
|
23
|
Activity-Induced Synaptic Structural Modifications by an Activator of Integrin Signaling at the Drosophila Neuromuscular Junction. J Neurosci 2017; 37:3246-3263. [PMID: 28219985 DOI: 10.1523/jneurosci.3128-16.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/08/2017] [Accepted: 02/14/2017] [Indexed: 11/21/2022] Open
Abstract
Activity-induced synaptic structural modification is crucial for neural development and synaptic plasticity, but the molecular players involved in this process are not well defined. Here, we report that a protein named Shriveled (Shv) regulates synaptic growth and activity-dependent synaptic remodeling at the Drosophila neuromuscular junction. Depletion of Shv causes synaptic overgrowth and an accumulation of immature boutons. We find that Shv physically and genetically interacts with βPS integrin. Furthermore, Shv is secreted during intense, but not mild, neuronal activity to acutely activate integrin signaling, induce synaptic bouton enlargement, and increase postsynaptic glutamate receptor abundance. Consequently, loss of Shv prevents activity-induced synapse maturation and abolishes post-tetanic potentiation, a form of synaptic plasticity. Our data identify Shv as a novel trans-synaptic signal secreted upon intense neuronal activity to promote synapse remodeling through integrin receptor signaling.SIGNIFICANCE STATEMENT The ability of neurons to rapidly modify synaptic structure in response to neuronal activity, a process called activity-induced structural remodeling, is crucial for neuronal development and complex brain functions. The molecular players that are important for this fundamental biological process are not well understood. Here we show that the Shriveled (Shv) protein is required during development to maintain normal synaptic growth. We further demonstrate that Shv is selectively released during intense neuronal activity, but not mild neuronal activity, to acutely activate integrin signaling and trigger structural modifications at the Drosophila neuromuscular junction. This work identifies Shv as a key modulator of activity-induced structural remodeling and suggests that neurons use distinct molecular cues to differentially modulate synaptic growth and remodeling to meet synaptic demand.
Collapse
|
24
|
Luo X, Shi X, Yuan C, Ai M, Ge C, Hu M, Feng X, Yang X. Genome-wide SNP analysis using 2b-RAD sequencing identifies the candidate genes putatively associated with resistance to ivermectin in Haemonchus contortus. Parasit Vectors 2017; 10:31. [PMID: 28095895 PMCID: PMC5240194 DOI: 10.1186/s13071-016-1959-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/27/2016] [Indexed: 01/15/2023] Open
Abstract
Background The excessive and uncontrolled use of anthelmintics, e.g. ivermectin (IVM) for the treatment of livestock parasites has led to widespread resistance in gastrointestinal nematodes, such as Haemonchus contortus. There is an urgent need for better management of drug-use in nematode control and development of novel anthelmintics. Discovery and identification of anthelmintic resistance-associate molecules/markers can provide a basis for rational anthelmintics-use and development of novel drugs. Recent studies have shown that ivermectin resistance in H. contortus is likely to be multi-genic in nature except for several genes coding for IVM target and efflux pump. However, no other IVM resistance-associated genes were characterized by conventional methods or strategies. In the present study we adopted a new strategy, i.e. using genome-wide single nucleotide polymorphism (SNP) analysis based on 2b-RAD sequencing, for discovering SNPs markers across the genomes in both IVM susceptible and resistant isolates of H. contortus and identifying potential IVM resistance-associated genes. Results We discovered 2962 and 2667 SNPs within both susceptible and resistant strains of H. contortus, respectively. A relative lower and similar genetic variations were observed within both resistant and susceptible strains (average π values were equal to 0.1883 and 0.1953, respectively); whereas a high genetic variation was found across both strains (average π value was equal to 0.3899). A significant differentiation across 2b-RAD tags nucleotide sites was also observed between the two strains (average FST value was equal to 0.3076); the larger differences in average FST were observed at SNPs loci between coding and noncoding (including intronic) regions. Comparison between resistant and susceptible strains revealed that 208 SNPs loci exhibited significantly elevated FST values, 24 SNPs of those loci were located in the CDS regions of the nine genes and were likely to have signature of IVM directional selection. Seven of the nine candidate genes were predicted to code for some functional proteins such as potential IVM target and/or efflux pump proteins, component proteins of receptor complex in membrane on neuromuscular cells, and transcriptional regulation proteins. Those genes might be involved in resistance to IVM. Conclusions Our data suggest that candidate genes putatively associated with resistance to IVM in H. contortus may be identified by genome-wide SNP analysis using 2b-RAD sequencing. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1959-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xiaoping Luo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.,College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, 010010, Inner Mongolia Nationality Autonomous, People's Republic of China
| | - Xiaona Shi
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.,College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 250014, People's Republic of China
| | - Chunxiu Yuan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, Jiangsu Province, People's Republic of China
| | - Min Ai
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China
| | - Cheng Ge
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.,College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 250014, People's Republic of China
| | - Min Hu
- State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, Hubei Province, People's Republic of China
| | - Xingang Feng
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, 200241, People's Republic of China.
| | - Xiaoye Yang
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, 010010, Inner Mongolia Nationality Autonomous, People's Republic of China.
| |
Collapse
|
25
|
Foo M, Sawlekar R, Bates DG. Exploiting the dynamic properties of covalent modification cycle for the design of synthetic analog biomolecular circuitry. J Biol Eng 2016; 10:15. [PMID: 27872658 PMCID: PMC5108087 DOI: 10.1186/s13036-016-0036-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 10/19/2016] [Indexed: 01/22/2023] Open
Abstract
Background Cycles of covalent modification are ubiquitous motifs in cellular signalling. Although such signalling cycles are implemented via a highly concise set of chemical reactions, they have been shown to be capable of producing multiple distinct input-output mapping behaviours – ultrasensitive, hyperbolic, signal-transducing and threshold-hyperbolic. Results In this paper, we show how the set of chemical reactions underlying covalent modification cycles can be exploited for the design of synthetic analog biomolecular circuitry. We show that biomolecular circuits based on the dynamics of covalent modification cycles allow (a) the computation of nonlinear operators using far fewer chemical reactions than purely abstract designs based on chemical reaction network theory, and (b) the design of nonlinear feedback controllers with strong performance and robustness properties. Conclusions Our designs provide a more efficient route for translation of complex circuits and systems from chemical reactions to DNA strand displacement-based chemistry, thus facilitating their experimental implementation in future Synthetic Biology applications.
Collapse
Affiliation(s)
- Mathias Foo
- Warwick Integrative Synthetic Biology Centre, School of Engineering, University of Warwick, Coventry, CV4 7AL UK
| | - Rucha Sawlekar
- Warwick Integrative Synthetic Biology Centre, School of Engineering, University of Warwick, Coventry, CV4 7AL UK
| | - Declan G Bates
- Warwick Integrative Synthetic Biology Centre, School of Engineering, University of Warwick, Coventry, CV4 7AL UK
| |
Collapse
|
26
|
Presynaptic DLG regulates synaptic function through the localization of voltage-activated Ca(2+) Channels. Sci Rep 2016; 6:32132. [PMID: 27573697 PMCID: PMC5004195 DOI: 10.1038/srep32132] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 08/03/2016] [Indexed: 12/15/2022] Open
Abstract
The DLG-MAGUK subfamily of proteins plays a role on the recycling and clustering of glutamate receptors (GLUR) at the postsynaptic density. discs-large1 (dlg) is the only DLG-MAGUK gene in Drosophila and originates two main products, DLGA and DLGS97 which differ by the presence of an L27 domain. Combining electrophysiology, immunostaining and genetic manipulation at the pre and postsynaptic compartments we study the DLG contribution to the basal synaptic-function at the Drosophila larval neuromuscular junction. Our results reveal a specific function of DLGS97 in the regulation of the size of GLUR fields and their subunit composition. Strikingly the absence of any of DLG proteins at the presynaptic terminal disrupts the clustering and localization of the calcium channel DmCa1A subunit (Cacophony), decreases the action potential-evoked release probability and alters short-term plasticity. Our results show for the first time a crucial role of DLG proteins in the presynaptic function in vivo.
Collapse
|
27
|
Xu S, Panikker P, Iqbal S, Elefant F. Tip60 HAT Action Mediates Environmental Enrichment Induced Cognitive Restoration. PLoS One 2016; 11:e0159623. [PMID: 27454757 PMCID: PMC4959735 DOI: 10.1371/journal.pone.0159623] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/06/2016] [Indexed: 12/14/2022] Open
Abstract
Environmental enrichment (EE) conditions have beneficial effects for reinstating cognitive ability in neuropathological disorders like Alzheimer's disease (AD). While EE benefits involve epigenetic gene control mechanisms that comprise histone acetylation, the histone acetyltransferases (HATs) involved remain largely unknown. Here, we examine a role for Tip60 HAT action in mediating activity- dependent beneficial neuroadaptations to EE using the Drosophila CNS mushroom body (MB) as a well-characterized cognition model. We show that flies raised under EE conditions display enhanced MB axonal outgrowth, synaptic marker protein production, histone acetylation induction and transcriptional activation of cognition linked genes when compared to their genotypically identical siblings raised under isolated conditions. Further, these beneficial changes are impaired in both Tip60 HAT mutant flies and APP neurodegenerative flies. While EE conditions provide some beneficial neuroadaptive changes in the APP neurodegenerative fly MB, such positive changes are significantly enhanced by increasing MB Tip60 HAT levels. Our results implicate Tip60 as a critical mediator of EE-induced benefits, and provide broad insights into synergistic behavioral and epigenetic based therapeutic approaches for treatment of cognitive disorder.
Collapse
Affiliation(s)
- Songjun Xu
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Priyalakshmi Panikker
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Sahira Iqbal
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Felice Elefant
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| |
Collapse
|
28
|
The Amino Acid Transporter JhI-21 Coevolves with Glutamate Receptors, Impacts NMJ Physiology, and Influences Locomotor Activity in Drosophila Larvae. Sci Rep 2016; 6:19692. [PMID: 26805723 PMCID: PMC4726445 DOI: 10.1038/srep19692] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/16/2015] [Indexed: 01/14/2023] Open
Abstract
Changes in synaptic physiology underlie neuronal network plasticity and behavioral phenomena, which are adjusted during development. The Drosophila larval glutamatergic neuromuscular junction (NMJ) represents a powerful synaptic model to investigate factors impacting these processes. Amino acids such as glutamate have been shown to regulate Drosophila NMJ physiology by modulating the clustering of postsynaptic glutamate receptors and thereby regulating the strength of signal transmission from the motor neuron to the muscle cell. To identify amino acid transporters impacting glutmatergic signal transmission, we used Evolutionary Rate Covariation (ERC), a recently developed bioinformatic tool. Our screen identified ten proteins co-evolving with NMJ glutamate receptors. We selected one candidate transporter, the SLC7 (Solute Carrier) transporter family member JhI-21 (Juvenile hormone Inducible-21), which is expressed in Drosophila larval motor neurons. We show that JhI-21 suppresses postsynaptic muscle glutamate receptor abundance, and that JhI-21 expression in motor neurons regulates larval crawling behavior in a developmental stage-specific manner.
Collapse
|
29
|
Dear ML, Dani N, Parkinson W, Zhou S, Broadie K. Two classes of matrix metalloproteinases reciprocally regulate synaptogenesis. Development 2015; 143:75-87. [PMID: 26603384 DOI: 10.1242/dev.124461] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 11/18/2015] [Indexed: 01/10/2023]
Abstract
Synaptogenesis requires orchestrated intercellular communication between synaptic partners, with trans-synaptic signals necessarily traversing the extracellular synaptomatrix separating presynaptic and postsynaptic cells. Extracellular matrix metalloproteinases (Mmps) regulated by secreted tissue inhibitors of metalloproteinases (Timps), cleave secreted and membrane-associated targets to sculpt the extracellular environment and modulate intercellular signaling. Here, we test the roles of Mmp at the neuromuscular junction (NMJ) model synapse in the reductionist Drosophila system, which contains just two Mmps (secreted Mmp1 and GPI-anchored Mmp2) and one secreted Timp. We found that all three matrix metalloproteome components co-dependently localize in the synaptomatrix and show that both Mmp1 and Mmp2 independently restrict synapse morphogenesis and functional differentiation. Surprisingly, either dual knockdown or simultaneous inhibition of the two Mmp classes together restores normal synapse development, identifying a reciprocal suppression mechanism. The two Mmp classes co-regulate a Wnt trans-synaptic signaling pathway modulating structural and functional synaptogenesis, including the GPI-anchored heparan sulfate proteoglycan (HSPG) Wnt co-receptor Dally-like protein (Dlp), cognate receptor Frizzled-2 (Frz2) and Wingless (Wg) ligand. Loss of either Mmp1 or Mmp2 reciprocally misregulates Dlp at the synapse, with normal signaling restored by co-removal of both Mmp classes. Correcting Wnt co-receptor Dlp levels in both Mmp mutants prevents structural and functional synaptogenic defects. Taken together, these results identify an Mmp mechanism that fine-tunes HSPG co-receptor function to modulate Wnt signaling to coordinate synapse structural and functional development.
Collapse
Affiliation(s)
- Mary Lynn Dear
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
| | - Neil Dani
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
| | - William Parkinson
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
| | - Scott Zhou
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
| | - Kendal Broadie
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37235-1634, USA
| |
Collapse
|
30
|
Sturgeon M, Davis D, Albers A, Beatty D, Austin R, Ferguson M, Tounsel B, Liebl FLW. The Notch ligand E3 ligase, Mind Bomb1, regulates glutamate receptor localization in Drosophila. Mol Cell Neurosci 2015; 70:11-21. [PMID: 26596173 DOI: 10.1016/j.mcn.2015.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 11/09/2015] [Accepted: 11/16/2015] [Indexed: 12/29/2022] Open
Abstract
The postsynaptic density (PSD) is a protein-rich network important for the localization of postsynaptic glutamate receptors (GluRs) and for signaling downstream of these receptors. Although hundreds of PSD proteins have been identified, many are functionally uncharacterized. We conducted a reverse genetic screen for mutations that affected GluR localization using Drosophila genes that encode homologs of mammalian PSD proteins. 42.8% of the mutants analyzed exhibited a significant change in GluR localization at the third instar larval neuromuscular junction (NMJ), a model synapse that expresses homologs of AMPA receptors. We identified the E3 ubiquitin ligase, Mib1, which promotes Notch signaling, as a regulator of synaptic GluR localization. Mib1 positively regulates the localization of the GluR subunits GluRIIA, GluRIIB, and GluRIIC. Mutations in mib1 and ubiquitous expression of Mib1 that lacks its ubiquitin ligase activity result in the loss of synaptic GluRIIA-containing receptors. In contrast, overexpression of Mib1 in all tissues increases postsynaptic levels of GluRIIA. Cellular levels of Mib1 are also important for the structure of the presynaptic motor neuron. While deficient Mib1 signaling leads to overgrowth of the NMJ, ubiquitous overexpression of Mib1 results in a reduction in the number of presynaptic motor neuron boutons and branches. These synaptic changes may be secondary to attenuated glutamate release from the presynaptic motor neuron in mib1 mutants as mib1 mutants exhibit significant reductions in the vesicle-associated protein cysteine string protein and in the frequency of spontaneous neurotransmission.
Collapse
Affiliation(s)
- Morgan Sturgeon
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Dustin Davis
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Amanda Albers
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Derek Beatty
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Rik Austin
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Matt Ferguson
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Brittany Tounsel
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Faith L W Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States.
| |
Collapse
|
31
|
Harris KP, Littleton JT. Transmission, Development, and Plasticity of Synapses. Genetics 2015; 201:345-75. [PMID: 26447126 PMCID: PMC4596655 DOI: 10.1534/genetics.115.176529] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/28/2015] [Indexed: 01/03/2023] Open
Abstract
Chemical synapses are sites of contact and information transfer between a neuron and its partner cell. Each synapse is a specialized junction, where the presynaptic cell assembles machinery for the release of neurotransmitter, and the postsynaptic cell assembles components to receive and integrate this signal. Synapses also exhibit plasticity, during which synaptic function and/or structure are modified in response to activity. With a robust panel of genetic, imaging, and electrophysiology approaches, and strong evolutionary conservation of molecular components, Drosophila has emerged as an essential model system for investigating the mechanisms underlying synaptic assembly, function, and plasticity. We will discuss techniques for studying synapses in Drosophila, with a focus on the larval neuromuscular junction (NMJ), a well-established model glutamatergic synapse. Vesicle fusion, which underlies synaptic release of neurotransmitters, has been well characterized at this synapse. In addition, studies of synaptic assembly and organization of active zones and postsynaptic densities have revealed pathways that coordinate those events across the synaptic cleft. We will also review modes of synaptic growth and plasticity at the fly NMJ, and discuss how pre- and postsynaptic cells communicate to regulate plasticity in response to activity.
Collapse
Affiliation(s)
- Kathryn P Harris
- Department of Biology and Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - J Troy Littleton
- Department of Biology and Department of Brain and Cognitive Sciences, The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| |
Collapse
|
32
|
Ramos CI, Igiesuorobo O, Wang Q, Serpe M. Neto-mediated intracellular interactions shape postsynaptic composition at the Drosophila neuromuscular junction. PLoS Genet 2015; 11:e1005191. [PMID: 25905467 PMCID: PMC4408064 DOI: 10.1371/journal.pgen.1005191] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 04/02/2015] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanisms controlling the subunit composition of glutamate receptors are crucial for the formation of neural circuits and for the long-term plasticity underlying learning and memory. Here we use the Drosophila neuromuscular junction (NMJ) to examine how specific receptor subtypes are recruited and stabilized at synaptic locations. In flies, clustering of ionotropic glutamate receptors (iGluRs) requires Neto (Neuropillin and Tolloid-like), a highly conserved auxiliary subunit that is essential for NMJ assembly and development. Drosophila neto encodes two isoforms, Neto-α and Neto-β, with common extracellular parts and distinct cytoplasmic domains. Mutations that specifically eliminate Neto-β or its intracellular domain were generated. When Neto-β is missing or is truncated, the larval NMJs show profound changes in the subtype composition of iGluRs due to reduced synaptic accumulation of the GluRIIA subunit. Furthermore, neto-β mutant NMJs fail to accumulate p21-activated kinase (PAK), a critical postsynaptic component implicated in the synaptic stabilization of GluRIIA. Muscle expression of either Neto-α or Neto-β rescued the synaptic transmission at neto null NMJs, indicating that Neto conserved domains mediate iGluRs clustering. However, only Neto-β restored PAK synaptic accumulation at neto null NMJs. Thus, Neto engages in intracellular interactions that regulate the iGluR subtype composition by preferentially recruiting and/or stabilizing selective receptor subtypes.
Collapse
Affiliation(s)
- Cathy I. Ramos
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Oghomwen Igiesuorobo
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Qi Wang
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Mihaela Serpe
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
- * E-mail:
| |
Collapse
|
33
|
Singh S, Chand S, Singh NK, Sharma TR. Genome-Wide Distribution, Organisation and Functional Characterization of Disease Resistance and Defence Response Genes across Rice Species. PLoS One 2015; 10:e0125964. [PMID: 25902056 PMCID: PMC4406684 DOI: 10.1371/journal.pone.0125964] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 03/28/2015] [Indexed: 11/19/2022] Open
Abstract
The resistance (R) genes and defense response (DR) genes have become very important resources for the development of disease resistant cultivars. In the present investigation, genome-wide identification, expression, phylogenetic and synteny analysis was done for R and DR-genes across three species of rice viz: Oryza sativa ssp indica cv 93-11, Oryza sativa ssp japonica and wild rice species, Oryza brachyantha. We used the in silico approach to identify and map 786 R -genes and 167 DR-genes, 672 R-genes and 142 DR-genes, 251 R-genes and 86 DR-genes in the japonica, indica and O. brachyanth a genomes, respectively. Our analysis showed that 60.5% and 55.6% of the R-genes are tandemly repeated within clusters and distributed over all the rice chromosomes in indica and japonica genomes, respectively. The phylogenetic analysis along with motif distribution shows high degree of conservation of R- and DR-genes in clusters. In silico expression analysis of R-genes and DR-genes showed more than 85% were expressed genes showing corresponding EST matches in the databases. This study gave special emphasis on mechanisms of gene evolution and duplication for R and DR genes across species. Analysis of paralogs across rice species indicated 17% and 4.38% R-genes, 29% and 11.63% DR-genes duplication in indica and Oryza brachyantha, as compared to 20% and 26% duplication of R-genes and DR-genes in japonica respectively. We found that during the course of duplication only 9.5% of R- and DR-genes changed their function and rest of the genes have maintained their identity. Syntenic relationship across three genomes inferred that more orthology is shared between indica and japonica genomes as compared to brachyantha genome. Genome wide identification of R-genes and DR-genes in the rice genome will help in allele mining and functional validation of these genes, and to understand molecular mechanism of disease resistance and their evolution in rice and related species.
Collapse
Affiliation(s)
- Sangeeta Singh
- National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
- School of Life Sciences, Devi Ahilya University, Khandwa Road, Indore, 452017, India
| | - Suresh Chand
- School of Life Sciences, Devi Ahilya University, Khandwa Road, Indore, 452017, India
| | - N. K. Singh
- National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
| | - Tilak Raj Sharma
- National Research Center on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
- * E-mail:
| |
Collapse
|
34
|
Kim YJ, Igiesuorobo O, Ramos CI, Bao H, Zhang B, Serpe M. Prodomain removal enables neto to stabilize glutamate receptors at the Drosophila neuromuscular junction. PLoS Genet 2015; 11:e1004988. [PMID: 25723514 PMCID: PMC4344203 DOI: 10.1371/journal.pgen.1004988] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/06/2015] [Indexed: 11/24/2022] Open
Abstract
Stabilization of neurotransmitter receptors at postsynaptic specializations is a key step in the assembly of functional synapses. Drosophila Neto (Neuropillin and Tolloid-like protein) is an essential auxiliary subunit of ionotropic glutamate receptor (iGluR) complexes required for the iGluRs clustering at the neuromuscular junction (NMJ). Here we show that optimal levels of Neto are crucial for stabilization of iGluRs at synaptic sites and proper NMJ development. Genetic manipulations of Neto levels shifted iGluRs distribution to extrajunctional locations. Perturbations in Neto levels also produced small NMJs with reduced synaptic transmission, but only Neto-depleted NMJs showed diminished postsynaptic components. Drosophila Neto contains an inhibitory prodomain that is processed by Furin1-mediated limited proteolysis. neto null mutants rescued with a Neto variant that cannot be processed have severely impaired NMJs and reduced iGluRs synaptic clusters. Unprocessed Neto retains the ability to engage iGluRs in vivo and to form complexes with normal synaptic transmission. However, Neto prodomain must be removed to enable iGluRs synaptic stabilization and proper postsynaptic differentiation. Synapse development is initiated by genetic programs, but is coordinated by neuronal activity, by communication between the pre- and postsynaptic compartments, and by cellular signals that integrate the status of the whole organisms and its developmental progression. The molecular mechanisms underlining these processes are poorly understood. In particular, how neurotransmitter receptors are recruited and stabilized at central synapses remain the subject of intense research. The Drosophila NMJ is a glutamatergic synapse similar in composition and physiology with mammalian central excitatory synapses. Like mammals, Drosophila utilizes auxiliary subunit(s) to modulate the formation and function of glutamatergic synapses. We have previously reported that Neto is an auxiliary protein essential for functional glutamate receptors and for organization of postsynaptic specializations. Here we report that synapse assembly and NMJ development are exquisitely sensitive to postsynaptic Neto levels. Furthermore, we show that Neto activity is controlled by Furin-type proteases, which regulate the processing and maturation of many developmentally important proteins, from growth factors and neuropeptides to extracellular matrix components. Such concerted control may serve to coordinate synapse assembly with synapse growth and developmental progression.
Collapse
Affiliation(s)
- Young-Jun Kim
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Oghomwen Igiesuorobo
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Cathy I. Ramos
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
| | - Hong Bao
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Mihaela Serpe
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, Maryland, United States of America
- * E-mail:
| |
Collapse
|
35
|
Ghosh R, Vegesna S, Safi R, Bao H, Zhang B, Marenda DR, Liebl FLW. Kismet positively regulates glutamate receptor localization and synaptic transmission at the Drosophila neuromuscular junction. PLoS One 2014; 9:e113494. [PMID: 25412171 PMCID: PMC4239079 DOI: 10.1371/journal.pone.0113494] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/24/2014] [Indexed: 12/20/2022] Open
Abstract
The Drosophila neuromuscular junction (NMJ) is a glutamatergic synapse that is structurally and functionally similar to mammalian glutamatergic synapses. These synapses can, as a result of changes in activity, alter the strength of their connections via processes that require chromatin remodeling and changes in gene expression. The chromodomain helicase DNA binding (CHD) protein, Kismet (Kis), is expressed in both motor neuron nuclei and postsynaptic muscle nuclei of the Drosophila larvae. Here, we show that Kis is important for motor neuron synaptic morphology, the localization and clustering of postsynaptic glutamate receptors, larval motor behavior, and synaptic transmission. Our data suggest that Kis is part of the machinery that modulates the development and function of the NMJ. Kis is the homolog to human CHD7, which is mutated in CHARGE syndrome. Thus, our data suggest novel avenues of investigation for synaptic defects associated with CHARGE syndrome.
Collapse
Affiliation(s)
- Rupa Ghosh
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Srikar Vegesna
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Ramia Safi
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Hong Bao
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Daniel R. Marenda
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (FLWL); (DRM)
| | - Faith L. W. Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
- * E-mail: (FLWL); (DRM)
| |
Collapse
|
36
|
McDermott SM, Yang L, Halstead JM, Hamilton RS, Meignin C, Davis I. Drosophila Syncrip modulates the expression of mRNAs encoding key synaptic proteins required for morphology at the neuromuscular junction. RNA (NEW YORK, N.Y.) 2014; 20:1593-606. [PMID: 25171822 PMCID: PMC4174441 DOI: 10.1261/rna.045849.114] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 06/09/2014] [Indexed: 05/24/2023]
Abstract
Localized mRNA translation is thought to play a key role in synaptic plasticity, but the identity of the transcripts and the molecular mechanism underlying their function are still poorly understood. Here, we show that Syncrip, a regulator of localized translation in the Drosophila oocyte and a component of mammalian neuronal mRNA granules, is also expressed in the Drosophila larval neuromuscular junction, where it regulates synaptic growth. We use RNA-immunoprecipitation followed by high-throughput sequencing and qRT-PCR to show that Syncrip associates with a number of mRNAs encoding proteins with key synaptic functions, including msp-300, syd-1, neurexin-1, futsch, highwire, discs large, and α-spectrin. The protein levels of MSP-300, Discs large, and a number of others are significantly affected in syncrip null mutants. Furthermore, syncrip mutants show a reduction in MSP-300 protein levels and defects in muscle nuclear distribution characteristic of msp-300 mutants. Our results highlight a number of potential new players in localized translation during synaptic plasticity in the neuromuscular junction. We propose that Syncrip acts as a modulator of synaptic plasticity by regulating the translation of these key mRNAs encoding synaptic scaffolding proteins and other important components involved in synaptic growth and function.
Collapse
Affiliation(s)
- Suzanne M McDermott
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Lu Yang
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - James M Halstead
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Russell S Hamilton
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Carine Meignin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| |
Collapse
|
37
|
Kim MJ, O’Connor MB. Anterograde Activin signaling regulates postsynaptic membrane potential and GluRIIA/B abundance at the Drosophila neuromuscular junction. PLoS One 2014; 9:e107443. [PMID: 25255438 PMCID: PMC4177838 DOI: 10.1371/journal.pone.0107443] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/10/2014] [Indexed: 12/16/2022] Open
Abstract
Members of the TGF-β superfamily play numerous roles in nervous system development and function. In Drosophila, retrograde BMP signaling at the neuromuscular junction (NMJ) is required presynaptically for proper synapse growth and neurotransmitter release. In this study, we analyzed whether the Activin branch of the TGF-β superfamily also contributes to NMJ development and function. We find that elimination of the Activin/TGF-β type I receptor babo, or its downstream signal transducer smox, does not affect presynaptic NMJ growth or evoked excitatory junctional potentials (EJPs), but instead results in a number of postsynaptic defects including depolarized membrane potential, small size and frequency of miniature excitatory junction potentials (mEJPs), and decreased synaptic densities of the glutamate receptors GluRIIA and B. The majority of the defective smox synaptic phenotypes were rescued by muscle-specific expression of a smox transgene. Furthermore, a mutation in actβ, an Activin-like ligand that is strongly expressed in motor neurons, phenocopies babo and smox loss-of-function alleles. Our results demonstrate that anterograde Activin/TGF-β signaling at the Drosophila NMJ is crucial for achieving normal abundance and localization of several important postsynaptic signaling molecules and for regulating postsynaptic membrane physiology. Together with the well-established presynaptic role of the retrograde BMP signaling, our findings indicate that the two branches of the TGF-β superfamily are differentially deployed on each side of the Drosophila NMJ synapse to regulate distinct aspects of its development and function.
Collapse
Affiliation(s)
- Myung-Jun Kim
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Michael B. O’Connor
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
| |
Collapse
|
38
|
Morel V, Lepicard S, Rey AN, Parmentier ML, Schaeffer L. Drosophila Nesprin-1 controls glutamate receptor density at neuromuscular junctions. Cell Mol Life Sci 2014; 71:3363-79. [PMID: 24492984 PMCID: PMC11113563 DOI: 10.1007/s00018-014-1566-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 12/20/2013] [Accepted: 01/16/2014] [Indexed: 01/06/2023]
Abstract
Nesprin-1 is a core component of a protein complex connecting nuclei to cytoskeleton termed LINC (linker of nucleoskeleton and cytoskeleton). Nesprin-1 is anchored to the nuclear envelope by its C-terminal KASH domain, the disruption of which has been associated with neuronal and neuromuscular pathologies, including autosomal recessive cerebellar ataxia and Emery-Dreifuss muscular dystrophy. Here, we describe a new and unexpected role of Drosophila Nesprin-1, Msp-300, in neuromuscular junction. We show that larvae carrying a deletion of Msp-300 KASH domain (Msp-300 (∆KASH) ) present a locomotion defect suggestive of a myasthenia, and demonstrate the importance of muscle Msp-300 for this phenotype, using tissue-specific RNAi knock-down. We show that Msp-300 (∆KASH) mutants display abnormal neurotransmission at the larval neuromuscular junction, as well as an imbalance in postsynaptic glutamate receptor composition with a decreased percentage of GluRIIA-containing receptors. We could rescue Msp-300 (∆KASH) locomotion phenotypes by GluRIIA overexpression, suggesting that the locomotion impairment associated with the KASH domain deletion is due to a reduction in junctional GluRIIA. In summary, we found that Msp-300 controls GluRIIA density at the neuromuscular junction. Our results suggest that Drosophila is a valuable model for further deciphering how Nesprin-1 and LINC disruption may lead to neuronal and neuromuscular pathologies.
Collapse
Affiliation(s)
- Véronique Morel
- Equipe Différenciation Neuromusculaire, CNRS, UMR5239, Ecole Normale Supérieure-Lyon, 46 allée d'Italie, 69364, Lyon Cedex 07, France,
| | | | | | | | | |
Collapse
|
39
|
Gardiol A, St Johnston D. Staufen targets coracle mRNA to Drosophila neuromuscular junctions and regulates GluRIIA synaptic accumulation and bouton number. Dev Biol 2014; 392:153-67. [PMID: 24951879 PMCID: PMC4111903 DOI: 10.1016/j.ydbio.2014.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/08/2014] [Accepted: 06/09/2014] [Indexed: 11/28/2022]
Abstract
The post-synaptic translation of localised mRNAs has been postulated to underlie several forms of plasticity at vertebrate synapses, but the mechanisms that target mRNAs to these postsynaptic sites are not well understood. Here we show that the evolutionary conserved dsRNA binding protein, Staufen, localises to the postsynaptic side of the Drosophila neuromuscular junction (NMJ), where it is required for the localisation of coracle mRNA and protein. Staufen plays a well-characterised role in the localisation of oskar mRNA to the oocyte posterior, where Staufen dsRNA-binding domain 5 is specifically required for its translation. Removal of Staufen dsRNA-binding domain 5, disrupts the postsynaptic accumulation of Coracle protein without affecting the localisation of cora mRNA, suggesting that Staufen similarly regulates Coracle translation. Tropomyosin II, which functions with Staufen in oskar mRNA localisation, is also required for coracle mRNA localisation, suggesting that similar mechanisms target mRNAs to the NMJ and the oocyte posterior. Coracle, the orthologue of vertebrate band 4.1, functions in the anchoring of the glutamate receptor IIA subunit (GluRIIA) at the synapse. Consistent with this, staufen mutant larvae show reduced accumulation of GluRIIA at synapses. The NMJs of staufen mutant larvae have also a reduced number of synaptic boutons. Altogether, this suggests that this novel Staufen-dependent mRNA localisation and local translation pathway may play a role in the developmentally regulated growth of the NMJ.
Collapse
Affiliation(s)
- Alejandra Gardiol
- The WellcomeCRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, United Kingdom
| | - Daniel St Johnston
- The WellcomeCRUK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, United Kingdom.
| |
Collapse
|
40
|
Romano G, Klima R, Buratti E, Verstreken P, Baralle FE, Feiguin F. Chronological requirements of TDP-43 function in synaptic organization and locomotive control. Neurobiol Dis 2014; 71:95-109. [PMID: 25088713 DOI: 10.1016/j.nbd.2014.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 06/12/2014] [Accepted: 07/23/2014] [Indexed: 12/12/2022] Open
Abstract
Alterations in TDP-43 are commonly found in patients suffering from amyotrophic lateral sclerosis (ALS) and the genetic suppression of the conserved homologue in Drosophila (TBPH) provokes alterations in the functional organization of motoneuron synaptic terminals, resulting in locomotive defects and reduced life span. To gain more insight into this pathological process, it is of fundamental importance to establish when during the fly life cycle the lack of TBPH affects motoneuron activity and whether this is a reversible phenomenon. To achieve this, we conditionally expressed the endogenous protein in TBPH minus Drosophila neurons and found that TBPH is a short lived protein permanently required for Drosophila motility and synaptic assembly through the direct modulation of vesicular proteins, such as Syntaxin 1A, indicating that synaptic transmission defects are early pathological consequences of TBPH dysfunction in vivo. Importantly, TBPH late induction is able to recover synaptogenesis and locomotion in adult flies revealing an unexpected late-stage functional and structural neuronal plasticity. These observations suggest that late therapeutic approaches based on TDP-43 functionality may also be successful for the human pathology.
Collapse
Affiliation(s)
- Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | | | - Francisco E Baralle
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy.
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy.
| |
Collapse
|
41
|
Georgieva D, Petrova M, Molle E, Daskalovska I, Genova G. Drosophila DFMR1 Interacts with Genes of the Lgl-Pathway in the Brain Synaptic Architecture. BIOTECHNOL BIOTEC EQ 2014. [DOI: 10.5504/50yrtimb.2011.0010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
42
|
Machamer JB, Collins SE, Lloyd TE. The ALS gene FUS regulates synaptic transmission at the Drosophila neuromuscular junction. Hum Mol Genet 2014; 23:3810-22. [PMID: 24569165 DOI: 10.1093/hmg/ddu094] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in the RNA binding protein Fused in sarcoma (FUS) are estimated to account for 5-10% of all inherited cases of amyotrophic lateral sclerosis (ALS), but the function of FUS in motor neurons is poorly understood. Here, we investigate the early functional consequences of overexpressing wild-type or ALS-associated mutant FUS proteins in Drosophila motor neurons, and compare them to phenotypes arising from loss of the Drosophila homolog of FUS, Cabeza (Caz). We find that lethality and locomotor phenotypes correlate with levels of FUS transgene expression, indicating that toxicity in developing motor neurons is largely independent of ALS-linked mutations. At the neuromuscular junction (NMJ), overexpression of either wild-type or mutant FUS results in decreased number of presynaptic active zones and altered postsynaptic glutamate receptor subunit composition, coinciding with a reduction in synaptic transmission as a result of both reduced quantal size and quantal content. Interestingly, expression of human FUS downregulates endogenous Caz levels, demonstrating that FUS autoregulation occurs in motor neurons in vivo. However, loss of Caz from motor neurons increases synaptic transmission as a result of increased quantal size, suggesting that the loss of Caz in animals expressing FUS does not contribute to motor deficits. These data demonstrate that FUS/Caz regulates NMJ development and plays an evolutionarily conserved role in modulating the strength of synaptic transmission in motor neurons.
Collapse
Affiliation(s)
| | | | - Thomas E Lloyd
- Department of Neurology, and The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| |
Collapse
|
43
|
Mhatre SD, Satyasi V, Killen M, Paddock BE, Moir RD, Saunders AJ, Marenda DR. Synaptic abnormalities in a Drosophila model of Alzheimer's disease. Dis Model Mech 2014; 7:373-85. [PMID: 24487408 PMCID: PMC3944497 DOI: 10.1242/dmm.012104] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by memory loss and decreased synaptic function. Advances in transgenic animal models of AD have facilitated our understanding of this disorder, and have aided in the development, speed and efficiency of testing potential therapeutics. Recently, we have described the characterization of a novel model of AD in the fruit fly, Drosophila melanogaster, where we expressed the human AD-associated proteins APP and BACE in the central nervous system of the fly. Here we describe synaptic defects in the larval neuromuscular junction (NMJ) in this model. Our results indicate that expression of human APP and BACE at the larval NMJ leads to defective larval locomotion behavior, decreased presynaptic connections, altered mitochondrial localization in presynaptic motor neurons and decreased postsynaptic protein levels. Treating larvae expressing APP and BACE with the γ-secretase inhibitor L-685,458 suppresses the behavioral defects as well as the pre- and postsynaptic defects. We suggest that this model will be useful to assess and model the synaptic dysfunction normally associated with AD, and will also serve as a powerful in vivo tool for rapid testing of potential therapeutics for AD.
Collapse
Affiliation(s)
- Siddhita D Mhatre
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Parkinson W, Dear ML, Rushton E, Broadie K. N-glycosylation requirements in neuromuscular synaptogenesis. Development 2013; 140:4970-81. [PMID: 24227656 DOI: 10.1242/dev.099192] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Neural development requires N-glycosylation regulation of intercellular signaling, but the requirements in synaptogenesis have not been well tested. All complex and hybrid N-glycosylation requires MGAT1 (UDP-GlcNAc:α-3-D-mannoside-β1,2-N-acetylglucosaminyl-transferase I) function, and Mgat1 nulls are the most compromised N-glycosylation condition that survive long enough to permit synaptogenesis studies. At the Drosophila neuromuscular junction (NMJ), Mgat1 mutants display selective loss of lectin-defined carbohydrates in the extracellular synaptomatrix, and an accompanying accumulation of the secreted endogenous Mind the gap (MTG) lectin, a key synaptogenesis regulator. Null Mgat1 mutants exhibit strongly overelaborated synaptic structural development, consistent with inhibitory roles for complex/hybrid N-glycans in morphological synaptogenesis, and strengthened functional synapse differentiation, consistent with synaptogenic MTG functions. Synapse molecular composition is surprisingly selectively altered, with decreases in presynaptic active zone Bruchpilot (BRP) and postsynaptic Glutamate receptor subtype B (GLURIIB), but no detectable change in a wide range of other synaptic components. Synaptogenesis is driven by bidirectional trans-synaptic signals that traverse the glycan-rich synaptomatrix, and Mgat1 mutation disrupts both anterograde and retrograde signals, consistent with MTG regulation of trans-synaptic signaling. Downstream of intercellular signaling, pre- and postsynaptic scaffolds are recruited to drive synaptogenesis, and Mgat1 mutants exhibit loss of both classic Discs large 1 (DLG1) and newly defined Lethal (2) giant larvae [L(2)GL] scaffolds. We conclude that MGAT1-dependent N-glycosylation shapes the synaptomatrix carbohydrate environment and endogenous lectin localization within this domain, to modulate retention of trans-synaptic signaling ligands driving synaptic scaffold recruitment during synaptogenesis.
Collapse
Affiliation(s)
- William Parkinson
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
| | | | | | | |
Collapse
|
45
|
Lee HG, Zhao N, Campion BK, Nguyen MM, Selleck SB. Akt regulates glutamate receptor trafficking and postsynaptic membrane elaboration at the Drosophila neuromuscular junction. Dev Neurobiol 2013; 73:723-43. [PMID: 23592328 PMCID: PMC4352336 DOI: 10.1002/dneu.22086] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 03/16/2013] [Accepted: 04/12/2013] [Indexed: 12/21/2022]
Abstract
The Akt family of serine-threonine kinases integrates a myriad of signals governing cell proliferation, apoptosis, glucose metabolism, and cytoskeletal organization. Akt affects neuronal morphology and function, influencing dendrite growth and the expression of ion channels. Akt is also an integral element of PI3Kinase-target of rapamycin (TOR)-Rheb signaling, a pathway that affects synapse assembly in both vertebrates and Drosophila. Our recent findings demonstrated that disruption of this pathway in Drosophila is responsible for a number of neurodevelopmental deficits that may also affect phenotypes associated with tuberous sclerosis complex, a disorder resulting from mutations compromising the TSC1/TSC2 complex, an inhibitor of TOR (Dimitroff et al., 2012). Therefore, we examined the role of Akt in the assembly and physiological function of the Drosophila neuromuscular junction (NMJ), a glutamatergic synapse that displays developmental and activity-dependent plasticity. The single Drosophila Akt family member, Akt1 selectively altered the postsynaptic targeting of one glutamate receptor subunit, GluRIIA, and was required for the expansion of a specialized postsynaptic membrane compartment, the subsynaptic reticulum (SSR). Several lines of evidence indicated that Akt1 influences SSR assembly by regulation of Gtaxin, a Drosophila t-SNARE protein (Gorczyca et al., 2007) in a manner independent of the mislocalization of GluRIIA. Our findings show that Akt1 governs two critical elements of synapse development, neurotransmitter receptor localization, and postsynaptic membrane elaboration.
Collapse
Affiliation(s)
- Hyun-Gwan Lee
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802
| | | | | | | | | |
Collapse
|
46
|
Rapid feedback regulation of synaptic efficacy during high-frequency activity at the Drosophila larval neuromuscular junction. Proc Natl Acad Sci U S A 2013; 110:9142-7. [PMID: 23674684 DOI: 10.1073/pnas.1221314110] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
High-frequency firing of neurons depresses transmitter release at many synapses. At the glutamatergic synapse of the Drosophila larval neuromuscular junction, we find that presynaptic depression is modulated by postsynaptic ionotropic glutamate receptor (iGluR) activity. Although basal release at low frequency was insensitive to postsynaptic iGluR activity, recovery from depression elicited by high-frequency presynaptic trains decreased with partial block of native iGluRs. Moreover, recovery from depression increased with optical activation of the light-gated mammalian iGluR6 (LiGluR) expressed postsynaptically. The enhancement of recovery from depression occurred within 2 min of optical activation of LiGluR and persisted for minutes after optical deactivation. This effect depended on cAMP-dependent presynaptic recruitment of vesicles from the reserve pool. Our findings reveal a unique dimension to postsynaptic iGluR activity: fast retrograde signaling that preserves transmission efficacy during high-frequency presynaptic firing.
Collapse
|
47
|
Abstract
L-glutamate is the primary neurotransmitter at excitatory synapses in the vertebrate CNS and at arthropod neuromuscular junctions (NMJs). However, the molecular mechanisms that trigger the recruitment of glutamate receptors at the onset of synaptogenesis and promote their stabilization at postsynaptic densities remain poorly understood. We have reported the discovery of a novel, evolutionary conserved molecule, Neto, essential for clustering of ionotropic glutamate receptors (iGluRs) at Drosophila NMJ. Neto is the first auxiliary subunit described in Drosophila and is the only non-channel subunit absolutely required for functional iGluRs. Here we review the role of Drosophila Neto in synapse assembly, its similarities with other Neto proteins and a new perspective on how glutamatergic synapses are physically assembled and stabilized.
Collapse
Affiliation(s)
- Young-Jun Kim
- 1Program in Cellular Regulation and Metabolism; NICHD; NIH; Bethesda, MD USA
| | | |
Collapse
|
48
|
Long JB, Van Vactor D. Embryonic and larval neural connectivity: progressive changes in synapse form and function at the neuromuscular junction mediated by cytoskeletal regulation. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2013; 2:747-65. [PMID: 24123935 DOI: 10.1002/wdev.114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
During development, precise formation of millions of synaptic connections is critical for the formation of a functional nervous system. Synaptogenesis is a complex multistep process in which axons follow gradients of secreted and cell surface guidance cues to reach their target area, at which point they must accurately distinguish their specific target. Upon target recognition, the axonal growth cone undergoes rapid growth and morphological changes, ultimately forming a functional synapse that continues to remodel during activity-dependent plasticity. Significant evidence suggests that the underlying actin and microtubule (MT) cytoskeletons are key effectors throughout synaptogenesis downstream of numerous receptors and signaling pathways. An increasing number of cytoskeletal-associated proteins have been shown to influence actin and MT stability and dynamics and many of these regulators have been implicated during synaptic morphogenesis using both mammalian and invertebrate model systems. In this review, we present an overview of the role cytoskeletal regulators play during the formation of the Drosophila neuromuscular junction.
Collapse
Affiliation(s)
- Jennifer B Long
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | | |
Collapse
|
49
|
Staples J, Broadie K. The cell polarity scaffold Lethal Giant Larvae regulates synapse morphology and function. J Cell Sci 2013; 126:1992-2003. [PMID: 23444371 DOI: 10.1242/jcs.120139] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lethal Giant Larvae (LGL) is a cytosolic cell polarity scaffold whose loss dominantly enhances neuromuscular junction (NMJ) synaptic overgrowth caused by loss of the Fragile X Mental Retardation Protein (FMRP). However, direct roles for LGL in NMJ morphological and functional development have not before been tested. Here, we use confocal imaging and two-electrode voltage-clamp electrophysiology at the Drosophila larval NMJ to define the synaptic requirements of LGL. We find that LGL is expressed both pre- and postsynaptically, where the scaffold localizes at the membrane on both sides of the synaptic interface. We show that LGL has a cell autonomous presynaptic role facilitating NMJ terminal branching and synaptic bouton formation. Moreover, loss of both pre- and postsynaptic LGL strongly decreases evoked neurotransmission strength, whereas the frequency and amplitude of spontaneous synaptic vesicle fusion events is increased. Cell-targeted RNAi and rescue reveals separable pre- and postsynaptic LGL roles mediating neurotransmission. We show that presynaptic LGL facilitates the assembly of active zone vesicle fusion sites, and that neuronally targeted rescue of LGL is sufficient to ameliorate increased synaptic vesicle cycling imaged with FM1-43 dye labeling. Postsynaptically, we show that loss of LGL results in a net increase in total glutamate receptor (GluR) expression, associated with the selective elevation of GluRIIB subunit-containing receptors. Taken together, these data indicate that the presynaptic LGL scaffold facilitates the assembly of active zone fusion sites to regulate synaptic vesicle cycling, and that the postsynaptic LGL scaffold modulates glutamate receptor composition and function.
Collapse
Affiliation(s)
- Jon Staples
- Department of Biological Sciences, Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37212, USA
| | | |
Collapse
|
50
|
Menon KP, Carrillo RA, Zinn K. Development and plasticity of the Drosophila larval neuromuscular junction. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2013; 2:647-70. [PMID: 24014452 DOI: 10.1002/wdev.108] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Drosophila larval neuromuscular system is relatively simple, containing only 32 motor neurons in each abdominal hemisegment, and its neuromuscular junctions (NMJs) have been studied extensively. NMJ synapses exhibit developmental and functional plasticity while displaying stereotyped connectivity. Drosophila Type I NMJ synapses are glutamatergic, while the vertebrate NMJ uses acetylcholine as its primary neurotransmitter. The larval NMJ synapses use ionotropic glutamate receptors (GluRs) that are homologous to AMPA-type GluRs in the mammalian brain, and they have postsynaptic scaffolds that resemble those found in mammalian postsynaptic densities. These features make the Drosophila neuromuscular system an excellent genetic model for the study of excitatory synapses in the mammalian central nervous system. The first section of the review presents an overview of NMJ development. The second section describes genes that regulate NMJ development, including: (1) genes that positively and negatively regulate growth of the NMJ, (2) genes required for maintenance of NMJ bouton structure, (3) genes that modulate neuronal activity and alter NMJ growth, (4) genes involved in transsynaptic signaling at the NMJ. The third section describes genes that regulate acute plasticity, focusing on translational regulatory mechanisms. As this review is intended for a developmental biology audience, it does not cover NMJ electrophysiology in detail, and does not review genes for which mutations produce only electrophysiological but no structural phenotypes.
Collapse
Affiliation(s)
- Kaushiki P Menon
- Broad Center, Division of Biology, California Institute of Technology, Pasadena, CA, USA
| | | | | |
Collapse
|