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Boyd-Gibbins N, Tardieu CH, Blunskyte M, Kirkwood N, Somers J, Albert JT. Turnover and activity-dependent transcriptional control of NompC in the Drosophila ear. iScience 2021; 24:102486. [PMID: 34027326 PMCID: PMC8134069 DOI: 10.1016/j.isci.2021.102486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 02/17/2021] [Accepted: 04/27/2021] [Indexed: 01/17/2023] Open
Abstract
Across their lives, biological sensors maintain near-constant functional outputs despite countless exogenous and endogenous perturbations. This sensory homeostasis is the product of multiple dynamic equilibria, the breakdown of which contributes to age-related decline. The mechanisms of homeostatic maintenance, however, are still poorly understood. The ears of vertebrates and insects are characterized by exquisite sensitivities but also by marked functional vulnerabilities. Being under the permanent load of thermal and acoustic noise, auditory transducer channels exemplify the homeostatic challenge. We show that (1) NompC-dependent mechanotransducers in the ear of the fruit fly Drosophila melanogaster undergo continual replacement with estimated turnover times of 9.1 hr; (2) a de novo synthesis of NompC can restore transducer function in the adult ears of congenitally hearing-impaired flies; (3) key components of the auditory transduction chain, including NompC, are under activity-dependent transcriptional control, likely forming a transducer-operated mechanosensory gain control system that extends beyond hearing organs. De novo NompC synthesis restores auditory transduction in congenitally deafened flies. Complete turnover of NompC mechanotransducers within less than 24 hr. Activity-dependent transcriptional control of transducers controls auditory function.
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Affiliation(s)
| | - Camille H Tardieu
- Ear Institute, University College London, 332 Gray's Inn Road, London WC1X 8EE, UK
| | - Modesta Blunskyte
- Ear Institute, University College London, 332 Gray's Inn Road, London WC1X 8EE, UK
| | - Nerissa Kirkwood
- Ear Institute, University College London, 332 Gray's Inn Road, London WC1X 8EE, UK
| | - Jason Somers
- Ear Institute, University College London, 332 Gray's Inn Road, London WC1X 8EE, UK.,The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Joerg T Albert
- Ear Institute, University College London, 332 Gray's Inn Road, London WC1X 8EE, UK.,The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, Gower Street, London WC1E 6BT, UK.,Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6DE, UK
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Sun H, Du Y, Liu Z, Dong K. Distinct functional properties of sodium channel variants are associated with usage of alternative exons in Nilaparvata lugens. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 118:103292. [PMID: 31811885 PMCID: PMC7085919 DOI: 10.1016/j.ibmb.2019.103292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/26/2019] [Accepted: 12/01/2019] [Indexed: 05/04/2023]
Abstract
Voltage-gated sodium channels (Nav) are essential for electrical signaling in the nervous system. They are also the primary targets of several classes of insecticides including pyrethroids. There is only one sodium channel gene in most insect species, whereas mammals possess at least nine sodium channel genes. Extensive alternative splicing and RNA editing of sodium channel transcripts have been documented in many insect species. However, the functional consequences of these post-transcriptional events have been evaluated only in DmNav and BgNav from Drosophila melanogaster and Blattella germanica, respectively. In this study, we isolated 41 full-length cDNA clones encoding 34 sodium channel (NlNav) variants from a major rice pest, the brown planthopper (Nilaparvata lugens Stål). The 34 NlNav variants represent 24 distinct splicing types based on the usage of nine alternative exons, six of which, including exon b, have been previously reported in other insect species. When expressed in Xenopus oocytes, NlNav variants lacking exon b generated significantly larger sodium currents than variants possessing exon b, suggesting an inhibitory effect of exon b on sodium current expression. A similar effect has been reported for exon b from BgNav. Mutational analysis showed that three conserved amino acid residues encoded by exon b are critical for its inhibitory effect. In addition, mutually exclusive exons k/l contribute to distinct functional properties and channel sensitivity to pyrethroids. Altogether, these results show that alternative splicing generates functional diversity of sodium channels in this insect species and that the role of exon b in regulating neuronal excitability is likely conserved among insect species.
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Affiliation(s)
- Huahua Sun
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China; Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI, 48824, USA
| | - Yuzhe Du
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI, 48824, USA
| | - Zewen Liu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ke Dong
- Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI, 48824, USA.
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