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Boullot F, Castrec J, Bidault A, Dantas N, Payton L, Perrigault M, Tran D, Amzil Z, Boudry P, Soudant P, Hégaret H, Fabioux C. Molecular Characterization of Voltage-Gated Sodium Channels and Their Relations with Paralytic Shellfish Toxin Bioaccumulation in the Pacific Oyster Crassostrea gigas. Mar Drugs 2017; 15:md15010021. [PMID: 28106838 PMCID: PMC5295241 DOI: 10.3390/md15010021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 12/28/2022] Open
Abstract
Paralytic shellfish toxins (PST) bind to voltage-gated sodium channels (Nav) and block conduction of action potential in excitable cells. This study aimed to (i) characterize Nav sequences in Crassostrea gigas and (ii) investigate a putative relation between Nav and PST-bioaccumulation in oysters. The phylogenetic analysis highlighted two types of Nav in C. gigas: a Nav1 (CgNav1) and a Nav2 (CgNav2) with sequence properties of sodium-selective and sodium/calcium-selective channels, respectively. Three alternative splice transcripts of CgNav1 named A, B and C, were characterized. The expression of CgNav1, analyzed by in situ hybridization, is specific to nervous cells and to structures corresponding to neuromuscular junctions. Real-time PCR analyses showed a strong expression of CgNav1A in the striated muscle while CgNav1B is mainly expressed in visceral ganglia. CgNav1C expression is ubiquitous. The PST binding site (domain II) of CgNav1 variants possess an amino acid Q that could potentially confer a partial saxitoxin (STX)-resistance to the channel. The CgNav1 genotype or alternative splicing would not be the key point determining PST bioaccumulation level in oysters.
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Affiliation(s)
- Floriane Boullot
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Justine Castrec
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Adeline Bidault
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Natanael Dantas
- Laboratory of Immunology and Pathology of Invertebrates, Department of Molecular Biology, Exact and Natural Sciences Center, Federal University of Paraíba-Campus I, 58051-900 João Pessoa, PB, Brazil.
| | - Laura Payton
- UMR 5805 EPOC, CNRS-Équipe Écotoxicologie Aquatique, Université de Bordeaux, Station Marine d'Arcachon, 33120 Arcachon, France.
| | - Mickael Perrigault
- UMR 5805 EPOC, CNRS-Équipe Écotoxicologie Aquatique, Université de Bordeaux, Station Marine d'Arcachon, 33120 Arcachon, France.
| | - Damien Tran
- UMR 5805 EPOC, CNRS-Équipe Écotoxicologie Aquatique, Université de Bordeaux, Station Marine d'Arcachon, 33120 Arcachon, France.
| | - Zouher Amzil
- Laboratoire Phycotoxines, IFREMER, BP 21105, 44311 Nantes, France.
| | - Pierre Boudry
- Ifremer, UMR 6539 LEMAR CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Philippe Soudant
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Hélène Hégaret
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
| | - Caroline Fabioux
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, 29280 Plouzané, France.
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Cloning and molecular characterization of a putative voltage-gated sodium channel gene in the crayfish. INVERTEBRATE NEUROSCIENCE 2016; 16:2. [PMID: 27032955 DOI: 10.1007/s10158-016-0185-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 03/12/2016] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channel genes and associated proteins have been cloned and studied in many mammalian and invertebrate species. However, there is no data available about the sodium channel gene(s) in the crayfish, although the animal has frequently been used as a model to investigate various aspects of neural cellular and circuit function. In the present work, by using RNA extracts from crayfish abdominal ganglia samples, the complete open reading frame of a putative sodium channel gene has firstly been cloned and molecular properties of the associated peptide have been analyzed. The open reading frame of the gene has a length of 5793 bp that encodes for the synthesis of a peptide, with 1930 amino acids, that is 82% similar to the α-peptide of a sodium channel in a neighboring species, Cancer borealis. The transmembrane topology analysis of the crayfish peptide indicated a pattern of four folding domains with several transmembrane segments, as observed in other known voltage-gated sodium channels. Upon analysis of the obtained sequence, functional regions of the putative sodium channel responsible for the selectivity filter, inactivation gate, voltage sensor, and phosphorylation have been predicted. The expression level of the putative sodium channel gene, as defined by a qPCR method, was measured and found to be the highest in nervous tissue.
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Evolution of sodium channels predates the origin of nervous systems in animals. Proc Natl Acad Sci U S A 2011; 108:9154-9. [PMID: 21576472 DOI: 10.1073/pnas.1106363108] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Voltage-dependent sodium channels are believed to have evolved from calcium channels at the origin of the nervous system. A search of the genome of a single-celled choanoflagellate (the sister group of animals) identified a gene that is homologous to animal sodium channels and has a putative ion selectivity filter intermediate between calcium and sodium channels. Searches of a wide variety of animal genomes, including representatives of each basal lineage, revealed that similar homologs were retained in most lineages. One of these, the Placozoa, does not possess a nervous system. We cloned and sequenced the full choanoflagellate channel and parts of two placozoan channels from mRNA, showing that they are expressed. Phylogenetic analysis clusters the genes for these channels with other known sodium channels. From this phylogeny we infer ancestral states of the ion selectivity filter and show that this state has been retained in the choanoflagellate and placozoan channels. We also identify key gene duplications and losses and show convergent amino acid replacements at important points along the animal lineage.
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Physiological and chemical analysis of neurotransmitter candidates at a fast excitatory synapse in the jellyfish Cyanea capillata (Cnidaria, Scyphozoa). INVERTEBRATE NEUROSCIENCE 2009; 9:167-73. [DOI: 10.1007/s10158-009-0095-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 12/01/2009] [Indexed: 11/30/2022]
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Zhou W, Chung I, Liu Z, Goldin AL, Dong K. A Voltage-Gated Calcium-Selective Channel Encoded by a Sodium Channel-like Gene. Neuron 2004; 42:101-12. [PMID: 15066268 PMCID: PMC3065994 DOI: 10.1016/s0896-6273(04)00148-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Revised: 12/22/2003] [Accepted: 02/03/2004] [Indexed: 11/27/2022]
Abstract
BSC1, which was originally identified by its sequence similarity to voltage-gated Na(+) channels, encodes a functional voltage-gated cation channel whose properties differ significantly from Na(+) channels. BSC1 has slower kinetics of activation and inactivation than Na(+) channels, it is more selective for Ba(2+) than for Na(+), it is blocked by Cd(2+), and Na(+) currents through BSC1 are blocked by low concentrations of Ca(2+). All of these properties are more similar to voltage-gated Ca(2+) channels than to voltage-gated Na(+) channels. The selectivity for Ba(2+) is partially due to the presence of a glutamate in the pore-forming region of domain III, since replacing that residue with lysine (normally present in voltage-gated Na(+) channels) makes the channel more selective for Na(+). BSC1 appears to be the prototype of a novel family of invertebrate voltage-dependent cation channels with a close structural and evolutionary relationship to voltage-gated Na(+) and Ca(2+) channels.
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Affiliation(s)
- Wei Zhou
- Department of Microbiology and Molecular Genetics University of California, Irvine Irvine, California 92697
| | - Inbum Chung
- Department of Entomology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Zhiqi Liu
- Department of Entomology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Alan L. Goldin
- Department of Microbiology and Molecular Genetics University of California, Irvine Irvine, California 92697
- Correspondence: (K.D.); (A.L.G.)
| | - Ke Dong
- Department of Entomology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
- Correspondence: (K.D.); (A.L.G.)
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Liu Z, Chung I, Dong K. Alternative splicing of the BSC1 gene generates tissue-specific isoforms in the German cockroach. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2001; 31:703-713. [PMID: 11267908 DOI: 10.1016/s0965-1748(00)00178-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Voltage-gated sodium channels are integral transmembrane proteins responsible for the rapidly-rising phase of action potentials in most excitable cells. In mammals, the functional diversity and wide distribution of sodium channel proteins in various tissues and cell types are achieved mainly by selective expression of many distinct sodium channel genes. In the model insect, Drosophila melanogaster, however, only one confirmed sodium channel gene, para, and one putative sodium channel gene, DSC1, are known. We cloned and sequenced a DSC1 ortholog, BSC1, from the German cockroach, Blattella germanica. We found that the BSC1 transcript was present in a wide range of tissues, including nerve cord, muscle, gut, fat body and ovary, whereas the para transcript was detected only in nerve cord and muscle. Moreover, different tissues contained distinct alternatively spliced variants of BSC1, and two muscle-specific spliced variants are predicted to encode truncated proteins with only the first two of the four homologous domains. Therefore, alternative splicing and expression of distinct splicing variants in functionally different tissues may be a major mechanism by which insects increase BSC1 channel diversity in neuronal and non-neuronal tissues.
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Affiliation(s)
- Z Liu
- Department of Entomology, Michigan State University, 106 Center for Integrated Plant Systems, East Lansing, MI 48824, USA
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Nagahora H, Okada T, Yahagi N, Chong JA, Mandel G, Okamura Y. Diversity of voltage-gated sodium channels in the ascidian larval nervous system. Biochem Biophys Res Commun 2000; 275:558-64. [PMID: 10964703 DOI: 10.1006/bbrc.2000.3290] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To gain insight into the origin of the molecular diversity of voltage-gated sodium channels (NaVs), a putative sodium channel gene (TuNa2) was cloned from the protochordate ascidian. TuNa2 showed two unusual features in its primary structure; (1) lysine in the P-region of the third repeat, a critical site determining ion selectivity, was changed to glutamic acid, predicting that the ionic permeability would not be rigidly sodium-selective (2) the III-IV linker, determinant of fast inactivation, was only weakly conserved. In contrast with a pan-neuronally expressed NaV (TuNa1), expression of TuNa2 was confined to subsets of neurons including motor neurons, suggesting that TuNa2 plays specialized roles in electrical activities unique to these neurons. Basic FGF, a neural inducer in the ascidian embryo, induces TuNa2 RNA expression in the ectodermal cells at lower doses than that required for TuNa1 gene expression. Thus, two types of NaV may play distinct roles and their gene expressions are controlled by distinct mechanisms.
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Affiliation(s)
- H Nagahora
- Ion Channel Group, National Institute of Bioscience and Human-Technology, AIST, Higashi 1-1, Ibaraki, Tsukuba, 305, Japan
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