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Li J, Lyu B, Bi J, Shan R, Stanley D, Feng Q, Song Q. Partner of neuropeptide bursicon homodimer pburs mediates a novel antimicrobial peptide Ten3LP via Dif/Dorsal2 in Tribolium castaneum. Int J Biol Macromol 2023; 247:125840. [PMID: 37454995 DOI: 10.1016/j.ijbiomac.2023.125840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Bursicon is a cystine knot family neuropeptide, composed of two subunits, bursicon (burs) and partner of burs (pburs). The subunits can form heterodimers to regulate cuticle tanning and wing maturation and homodimers to signal different biological functions in innate immunity, midgut stem cell proliferation and energy homeostasis, and reproductive physiology in the model insects Drosophila melanogaster or Tribolium castaneum. Here, we report on the role of the pburs homodimer in signaling innate immunity in T. castaneum larvae. Through transcriptome analysis we identified a set of immune-related genes that respond to pburs RNAi. Treating larvae with recombinant-pburs protein led to up-regulation of antimicrobial peptide (AMP) genes in vivo and in vitro. The upregulation of most AMP genes was dependent on the NF-κB transcription factor Relish. Most importantly, we identified a novel AMP, Tenecin 3-like peptide (Ten3LP), regulated by pburs via NF-κB transcription factor Dorsal-related immunity factor (Dif)/Dorsal2, but not Relish. We conducted Ten3LP RNAi, synthesized recombinant Ten3LP protein for microbial inhibition assays and functionally characterized Ten3LP as an AMP specific for fungi and Gram-positive bacteria. We demonstrate that expression of Ten3LP is activated by pburs via the Toll pathway. These findings identify new molecular targets for development of potential antibiotics for treating microbial infections and perhaps for RNAi based pest management technology.
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Affiliation(s)
- Jingjing Li
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA.
| | - Bo Lyu
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA.
| | - Jingxiu Bi
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA; Institution of Quality Standard and Testing Technology for Agro-product, Shandong Academy of Agricultural Science, Jinan, Shandong 250100, China.
| | - Ruiqi Shan
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA.
| | - David Stanley
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA; Biological Control of Insect Research Laboratory, United States Department of Agriculture-Agricultural Research Station (USDA/ARS), Columbia, MO 65203, USA.
| | - Qili Feng
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China.
| | - Qisheng Song
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA.
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2
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Zhang CS, Sun LL, Xie JM, Cao CW. RNAi-based functional analysis of bursicon genes related to wing expansion in gypsy moths. JOURNAL OF INSECT PHYSIOLOGY 2022; 139:104398. [PMID: 35537524 DOI: 10.1016/j.jinsphys.2022.104398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/16/2022] [Accepted: 05/04/2022] [Indexed: 06/14/2023]
Abstract
Bursicon is a heterodimeric neuropeptide composed of Burs-α and Burs-β subunits that plays an important role in cuticle tanning and wing expansion in insects. In this study, full-length cDNAs of Burs-α (LdBurs-α) and Burs-β (LdBurs-β) genes were identified in gypsy moth (Lymantria dispar) and cloned. The 480 bp and 420 bp open reading frames (ORFs) encode 159 and 129 amino acid polypeptides, respectively. LdBurs-α and LdBurs-β have 11 conserved cysteine residues, and LdBurs-α and LdBurs-β genes were expressed during all developmental stages according to quantitative reverse transcription PCR (qRT-PCR), with highest expression in the egg stage. High expression levels were also detected in the haemolymph, cuticle and head. To explore the physiological functions of LdBurs-α and LdBurs-β, the genes were knocked down in larvae and pupae using RNA interference (RNAi), and expression levels of LdBurs-α and LdBurs-β were decreased by 42.26-80.09%. Wing defects were observed in L. dispar pupae following Ldbursion silencing, with a phenotypic percentage ranging from 10.17% to 15.00%. RNAi-mediated knockdown of Ldbursicon prevented the expansion of male and female L. dispar adult wings, with malformation rates ranging from 6.38% and 30.00% to 57.69% and 69.23%, but no cuticle tanning defects were observed in pupae or adults. The results indicate that bursicon plays a key role in wing expansion in L. dispar adults, making it a potentially novel molecular target for insecticide-based control of this pest species.
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Affiliation(s)
- Chen-Shu Zhang
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, PR China
| | - Li-Li Sun
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, PR China
| | - Jia-Ming Xie
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, PR China
| | - Chuan-Wang Cao
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, PR China.
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3
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Li J, Zhu Z, Bi J, Feng Q, Beerntsen BT, Song Q. Neuropeptide Bursicon Influences Reproductive Physiology in Tribolium Castaneum. Front Physiol 2021; 12:717437. [PMID: 34744761 PMCID: PMC8567023 DOI: 10.3389/fphys.2021.717437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Bursicon is a neuropeptide belonging to the cystine knot family and is composed of burs and partner of burs (pburs) subunits. It can form heterodimers or homodimers to execute different biological functions. Bursicon heterodimers regulate cuticle sclerotization and wing maturation, whereas bursicon homodimers mediate innate immunity and midgut stem cell proliferation. A recent study has shown that bursicon potentially induces the expression of vitellogenin (Vg) in the black tiger shrimp Penaeus monodon; however, the underlying mechanism remains unknown. In this study, we investigated the role of bursicon in the reproductive physiology of the red flour beetle, Tribolium castaneum. The knockdown of burs, pburs, or its receptor T. castaneum rickets (Tcrk) in 2-day pupae significantly downregulated the expression levels of Vg1, Vg2, and Vg receptor (VgR) genes in females 3- and 5-day post-adult emergence, leading to abnormal oocytes with limited Vg content. The silencing of burs repressed the number of eggs laid and completely inhibited egg hatch, whereas the silencing of pburs dramatically decreased the number of eggs laid, hatch rate, and offspring larval size, and this RNA interference (RNAi) effects persisted to the next generation. Furthermore, the knockdown of burs or pburs downregulated the expression of the insulin/insulin-like signaling/target of rapamycin (TOR) signaling genes encoding insulin receptor (InR), protein kinase B (Akt), TOR, and ribosomal protein S6 kinase (S6K). Most importantly, the injection of recombinant pburs (r-pburs) protein was able to upregulate the expression of Vg, VgR, InR, Akt, TOR, S6K, JH synthesis (JHAMT), Methoprene-tolerant (Met), and Taiman (Tai) in normal females and rescue the expression of Vg and VgR in pburs RNAi females but failed to rescue Vg and VgR in Tcrk knockdown females. We infer that bursicon homodimers influence Vg expression via the receptor Tcrk, possibly by mediating the expression of the juvenile hormone (JH) and IIS/TOR pathway genes, thereby regulating reproduction in T. castaneum.
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Affiliation(s)
- Jingjing Li
- Division of Plant Science and Technology, University of Missouri, Columbia, MO, United States
| | - Zidan Zhu
- Division of Plant Science and Technology, University of Missouri, Columbia, MO, United States.,Guangdong Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology and School of Life Sciences, South China Normal University, Guangzhou, China
| | - Jingxiu Bi
- Division of Plant Science and Technology, University of Missouri, Columbia, MO, United States.,Institution of Quality Standard and Testing Technology for Agro-Product, Shandong Academy of Agricultural Science, Jinan, China
| | - Qili Feng
- Guangdong Key Laboratory of Insect Developmental Biology and Applied Technology, Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology and School of Life Sciences, South China Normal University, Guangzhou, China
| | - Brenda T Beerntsen
- Division of Plant Science and Technology, University of Missouri, Columbia, MO, United States.,Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, United States
| | - Qisheng Song
- Division of Plant Science and Technology, University of Missouri, Columbia, MO, United States
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Endress M, Zatylny-Gaudin C, Corre E, Le Corguillé G, Benoist L, Leprince J, Lefranc B, Bernay B, Leduc A, Rangama J, Lafont AG, Bondon A, Henry J. Crustacean cardioactive peptides: Expression, localization, structure, and a possible involvement in regulation of egg-laying in the cuttlefish Sepia officinalis. Gen Comp Endocrinol 2018; 260:67-79. [PMID: 29278693 DOI: 10.1016/j.ygcen.2017.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/26/2017] [Accepted: 12/20/2017] [Indexed: 02/07/2023]
Abstract
The cuttlefish (Sepia officinalis) is a cephalopod mollusk distributed on the western European coast, in the West African Ocean and in the Mediterranean Sea. On the Normandy coast (France), cuttlefish is a target species of professional fishermen, so its reproduction strategy is of particular interest in the context of stock management. Egg-laying, which is coastal, is controlled by several types of regulators among which neuropeptides. The cuttlefish neuropeptidome was recently identified by Zatylny-Gaudin et al. (2016). Among the 38 neuropeptide families identified, some were significantly overexpressed in egg-laying females as compared to mature males. This study is focused on crustacean cardioactive peptides (CCAPs), a highly expressed neuropeptide family strongly suspected of being involved in the control of egg-laying. We investigated the functional and structural characterization and tissue mapping of CCAPs, as well as the expression patterns of their receptors. CCAPs appeared to be involved in oocyte transport through the oviduct and in mechanical secretion of capsular products. Immunocytochemistry revealed that the neuropeptides were localized throughout the central nervous system (CNS) and in the nerve endings of the glands involved in egg-capsule synthesis and secretion, i.e. the oviduct gland and the main nidamental glands. The CCAP receptor was expressed in these glands and in the subesophageal mass of the CNS. Multiple sequence alignments revealed a high level of conservation of CCAP protein precursors in Sepia officinalis and Loligo pealei, two cephalopod decapods. Primary sequences of CCAPs from the two species were fully conserved, and cryptic peptides detected in the nerve endings were also partially conserved, suggesting biological activity that remains unknown for the time being.
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Affiliation(s)
- Maxime Endress
- Normandy University, UNICAEN, Sorbonne Universités, MNHN, UPMC Univ Paris 06, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), F-14032 Caen, France
| | - Céline Zatylny-Gaudin
- Normandy University, UNICAEN, Sorbonne Universités, MNHN, UPMC Univ Paris 06, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), F-14032 Caen, France
| | - Erwan Corre
- UPMC, CNRS, FR2424, ABiMS, Station Biologique, F-29680 Roscoff, France
| | | | - Louis Benoist
- Normandy University, UNICAEN, Sorbonne Universités, MNHN, UPMC Univ Paris 06, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), F-14032 Caen, France
| | - Jérôme Leprince
- Normandy University, UNIROUEN, INSERM, U1239, Laboratoire Différenciation et Communication Neuronale et Neuroendocrine, Institut de Recherche et d'Innovation Biomédicale de Normandie, F-76000 Rouen, France
| | - Benjamin Lefranc
- Normandy University, UNIROUEN, INSERM, U1239, Laboratoire Différenciation et Communication Neuronale et Neuroendocrine, Institut de Recherche et d'Innovation Biomédicale de Normandie, F-76000 Rouen, France
| | - Benoît Bernay
- Normandy University, Post Genomic Platform PROTEOGEN, SF ICORE 4206, F-14032 Caen, France
| | - Alexandre Leduc
- Normandy University, UNICAEN, Sorbonne Universités, MNHN, UPMC Univ Paris 06, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), F-14032 Caen, France
| | - Jimmy Rangama
- Normandy University, CIMAP, UMP 6252 (CEA/CNRS/ENSICAEN/Normandy University), Caen, France
| | - Anne-Gaëlle Lafont
- Equipe CORINT, UMR CNRS 6226, PRISM, CS 34317, Campus de Villejean, Université de Rennes 1, F-35043 Rennes, France
| | - Arnaud Bondon
- Equipe CORINT, UMR CNRS 6226, PRISM, CS 34317, Campus de Villejean, Université de Rennes 1, F-35043 Rennes, France
| | - Joël Henry
- Normandy University, UNICAEN, Sorbonne Universités, MNHN, UPMC Univ Paris 06, UA, CNRS, IRD, Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), F-14032 Caen, France; Normandy University, Post Genomic Platform PROTEOGEN, SF ICORE 4206, F-14032 Caen, France.
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5
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Scopelliti A, Bauer C, Cordero JB, Vidal M. Bursicon-α subunit modulates dLGR2 activity in the adult Drosophila melanogaster midgut independently to Bursicon-β. Cell Cycle 2016; 15:1538-44. [PMID: 27191973 PMCID: PMC4934083 DOI: 10.1080/15384101.2015.1121334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Bursicon is the main regulator of post molting and post eclosion processes during arthropod development. The active Bursicon hormone is a heterodimer of Burs-α and Burs-β. However, adult midguts express Burs-α to regulate the intestinal stem cell niche. Here, we examined the potential expression and function of its heterodimeric partner, Burs-β in the adult midgut. Unexpectedly, our evidence suggests that Burs-β is not significantly expressed in the adult midgut. burs-β mutants displayed the characteristic developmental defects but showed wild type-like adult midguts, thus uncoupling the developmental and adult phenotypes seen in burs-α mutants. Gain of function data and ex vivo experiments using a cAMP biosensor, demonstrated that Burs-α is sufficient to drive stem cell quiescence and to activate dLGR2 in the adult midgut. Our evidence suggests that the post developmental transactivation of dLGR2 in the adult midgut is mediated by Burs-α and that the β subunit of Bursicon is dispensable for these activities.
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Affiliation(s)
| | - Christin Bauer
- a The Beatson Institute for Cancer Research, Garscube Estate , Glasgow , UK
| | | | - Marcos Vidal
- a The Beatson Institute for Cancer Research, Garscube Estate , Glasgow , UK
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6
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Möller C, Melaun C, Castillo C, Díaz ME, Renzelman CM, Estrada O, Kuch U, Lokey S, Marí F. Functional hypervariability and gene diversity of cardioactive neuropeptides. J Biol Chem 2010; 285:40673-80. [PMID: 20923766 DOI: 10.1074/jbc.m110.171397] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Crustacean cardioactive peptide (CCAP) and related peptides are multifunctional regulatory neurohormones found in invertebrates. We isolated a CCAP-related peptide (conoCAP-a, for cone snail CardioActive Peptide) and cloned the cDNA of its precursor from venom of Conus villepinii. The precursor of conoCAP-a encodes for two additional CCAP-like peptides: conoCAP-b and conoCAP-c. This multi-peptide precursor organization is analogous to recently predicted molluscan CCAP-like preprohormones, and suggests a mechanism for the generation of biological diversification without gene amplification. While arthropod CCAP is a cardio-accelerator, we found that conoCAP-a decreases the heart frequency in Drosophila larvae, demonstrating that conoCAP-a and CCAP have opposite effects. Intravenous injection of conoCAP-a in rats caused decreased heart frequency and blood pressure in contrast to the injection of CCAP, which did not elicit any cardiac effect. Perfusion of rat ventricular cardiac myocytes with conoCAP-a decreased systolic calcium, indicating that conoCAP-a cardiac negative inotropic effects might be mediated via impairment of intracellular calcium trafficking. The contrasting cardiac effects of conoCAP-a and CCAP indicate that molluscan CCAP-like peptides have functions that differ from those of their arthropod counterparts. Molluscan CCAP-like peptides sequences, while homologous, differ between taxa and have unique sequences within a species. This relates to the functional hypervariability of these peptides as structure activity relationship studies demonstrate that single amino acids variations strongly affect cardiac activity. The discovery of conoCAPs in cone snail venom emphasizes the significance of their gene plasticity to have mutations as an adaptive evolution in terms of structure, cellular site of expression, and physiological functions.
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Affiliation(s)
- Carolina Möller
- Department of Chemistry & Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, USA
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7
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Sharp JH, Wilcockson DC, Webster SG. Identification and expression of mRNAs encoding bursicon in the plesiomorphic central nervous system of Homarus gammarus. Gen Comp Endocrinol 2010; 169:65-74. [PMID: 20691691 DOI: 10.1016/j.ygcen.2010.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 07/07/2010] [Accepted: 07/21/2010] [Indexed: 11/15/2022]
Abstract
Ecdysis in arthropods is a complex process, regulated by many neurohormones, which must be released in a precisely coordinated manner. In insects, the ultimate hormone involved in this process is the cuticle tanning hormone, bursicon. Recently, this hormone has been identified in crustaceans. To further define the distribution of bursicon in crustacean nervous systems, and to compare hormone structures within the sub-phylum, cDNAs encoding both bursicon subunits were cloned and sequenced from the nervous system of the European lobster, Homarus gammarus, and expression patterns including those for CCAP determined using in-situ hybridisation, quantitative RT-PCR and immunohistochemistry. Full-length cDNAs encoded bursicon subunits of 121 amino acids (Average M(r): 13365.48) for Burs α, 115 amino acids (Average M(r): 12928.54) for Burs β. Amino acid sequences were most closely related to those of crabs, and for Burs β the sequence was identical to that of the American lobster, Homarus americanus. Complete co-localisation with CCAP in the VNC was seen. Copy numbers burs α, burs β and CCAP mRNAs were between 0.5 and 1.5 × 10(5) for both bursicon subunits, 0.5-6 × 10(5) per cdn neurone for CCAP. The terminal abdominal ganglia (AG 6-8) contained about 52 cdn-type neurons, making it the largest bursicon producing region in the CNS. Double labelling IHC using recombinant Carcinus Burs α and CCAP antisera demonstrated complete co-localisation in the VNC. On the basis of the results obtained, it is proposed that CCAP and bursicon release occur simultaneously during ecdysis in crustaceans.
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Affiliation(s)
- Jasmine H Sharp
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
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8
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Barker N, Clevers H. Leucine-rich repeat-containing G-protein-coupled receptors as markers of adult stem cells. Gastroenterology 2010; 138:1681-96. [PMID: 20417836 DOI: 10.1053/j.gastro.2010.03.002] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/03/2010] [Accepted: 03/05/2010] [Indexed: 12/18/2022]
Abstract
Molecular markers are used to characterize and track adult stem cells. Colon cancer research has led to the identification of 2 related receptors, leucine-rich repeat-containing, G-protein-coupled receptors (Lgr)5 and Lgr6, that are expressed by small populations of cells in a variety of adult organs. Genetic mouse models have allowed the visualization, isolation, and genetic marking of Lgr5(+ve) and Lgr6(+ve) cells and provided evidence that they are stem cells. The Lgr5(+ve) cells were found to occupy locations not commonly associated with stem cells in the stomach, small intestine, colon, and hair follicles. A multipotent population of skin stem cells express Lgr6. Single Lgr5(+ve) stem cells from the small intestine and the stomach can be cultured into long-lived organoids. Further studies of these markers might reveal adult stem cell populations in additional tissues. Identification of the ligands for Lgr5 and 6 will help elucidate stem cell functions and modes of intracellular signaling.
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Affiliation(s)
- Nick Barker
- Hubrecht Institute, Uppsalalaan, Utrecht, The Netherlands.
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Asuncion-Uchi M, Shawa HE, Martin T, Fuse M. Different actions of ecdysis-triggering hormone on the brain and ventral nerve cord of the hornworm, Manduca sexta. Gen Comp Endocrinol 2010; 166:54-65. [PMID: 19699740 PMCID: PMC2823964 DOI: 10.1016/j.ygcen.2009.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/23/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
Abstract
Ecdysis, or the shedding of the old cuticle, depends on coordinated stereotyped behaviors, regulated by a number of neuropeptides. In the hornworm, Manduca sexta, two neuropeptides interact, namely ecdysis-triggering hormone (ETH) and eclosion hormone. We looked at the effects of ETH in vivo and in vitro, on the brain and the ventral nerve cord to determine the roles played by these hormones. We monitored ecdysis onset and the presence of cGMP and eclosion hormone immunoreactivity. In vivo, only a fraction of larvae lacking the cell bodies containing eclosion hormone, and injected with ETH, were able to undergo ecdysis, with a delayed response. These animals showed strongest cGMP immunoreactivity in the subesophageal and thoracic ganglia, with concomitant reductions in eclosion hormone immunoreactivity in descending axons in comparison with animals not undergoing ecdysis. Animals lacking the brain showed reduced to no cGMP levels in all ganglia. In vitro, isolated CNS preparations lacking the brain initiated ecdysis motor programs after incubation in ETH, with faster onset times than controls, and with reduced cGMP immunoreactivity. If ETH was applied only to the brain of the isolated CNS, cGMP immunoreactivity was noted primarily in the subesophageal and thoracic ganglia, with a decrease in eclosion hormone immunoreactivity in descending axons. ETH addition to the rest of the nerve cord showed reduced eclosion hormone immunoreactivity but little to no cGMP immunoreactivity in any ganglion. Controls showed strong cGMP immunoreactivity in all ganglia, and even greater reductions in eclosion hormone staining after ETH application. These results support previous suggestions that eclosion hormone is required for a positive feedback loop with ETH as well as onset of an inhibitory component, but also suggest that ETH stimulates eclosion hormone release at multiple spike initiation zones. The resultant up regulation of cGMP does not appear to be required for onset of ecdysis. A new model for ecdysis regulation is considered.
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Affiliation(s)
| | - Hani El Shawa
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Tunyalee Martin
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Megumi Fuse
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Corresponding author: ; fax (415-338-1130); phone (415-405-0728)
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10
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Bursicon functions within the Drosophila CNS to modulate wing expansion behavior, hormone secretion, and cell death. J Neurosci 2009; 28:14379-91. [PMID: 19118171 DOI: 10.1523/jneurosci.2842-08.2008] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Hormones are often responsible for synchronizing somatic physiological changes with changes in behavior. Ecdysis (i.e., the shedding of the exoskeleton) in insects has served as a useful model for elucidating the molecular and cellular mechanisms of this synchronization, and has provided numerous insights into the hormonal coordination of body and behavior. An example in which the mechanisms have remained enigmatic is the neurohormone bursicon, which, after the final molt, coordinates the plasticization and tanning of the initially folded wings with behaviors that drive wing expansion. The somatic effects of the hormone are governed by bursicon that is released into the blood from neurons in the abdominal ganglion (the B(AG)), which die after wing expansion. How bursicon induces the behavioral programs required for wing expansion, however, has remained unknown. Here we show by targeted suppression of excitability that a pair of bursicon-immunoreactive neurons distinct from the B(AG) and located within the subesophageal ganglion in Drosophila (the B(SEG)) is involved in controlling wing expansion behaviors. Unlike the B(AG), the B(SEG) arborize widely in the nervous system, including within the abdominal neuromeres, suggesting that, in addition to governing behavior, they also may modulate the B(AG.) Indeed, we show that animals lacking bursicon receptor function have deficits both in the humoral release of bursicon and in posteclosion apoptosis of the B(AG). Our results reveal novel neuromodulatory functions for bursicon and support the hypothesis that the B(SEG) are essential for orchestrating both the behavioral and somatic processes underlying wing expansion.
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11
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Woodruff EA, Broadie K, Honegger HW. Two peptide transmitters co-packaged in a single neurosecretory vesicle. Peptides 2008; 29:2276-80. [PMID: 18848852 PMCID: PMC2637405 DOI: 10.1016/j.peptides.2008.08.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 08/29/2008] [Accepted: 08/29/2008] [Indexed: 11/21/2022]
Abstract
Numerous neurosecretory cells are known to secrete more than one peptide, in both vertebrates and invertebrates. These co-expressed neuropeptides often originate from differential cleavage of a single large precursor, and are then usually sorted in the regulated pathway into different secretory vesicle classes to allow separable release dynamics. Here, we use immuno-gold electron microscopy to show that two very different neuropeptides (the nonapeptide crustacean cardioactive peptide (CCAP) and the 30 kDa heterodimeric bursicon) are co-packaged within the same dense core vesicles in neurosecretory neurons in the abdominal ganglia of Periplaneta americana. We suggest that this co-packaging serves a physiological function in which CCAP accelerates the distribution of bursicon to the epidermis after ecdysis to regulate sclerotization of the newly formed cuticle.
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Affiliation(s)
| | | | - Hans-Willi Honegger
- Corresponding author: , Department of Biological Sciences Vanderbilt University, VU Station B, Box 35-1634, Nashville, TN 37235-1634 USA, Phone: 615-343-6217 Fax: 615-343-6707
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12
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Bursicon, the tanning hormone of insects: recent advances following the discovery of its molecular identity. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2008; 194:989-1005. [PMID: 19005656 DOI: 10.1007/s00359-008-0386-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 10/20/2008] [Accepted: 10/23/2008] [Indexed: 10/21/2022]
Abstract
Bursicon was identified in 1965 as a peptide neurohormone that initiates the tanning of the insect cuticle immediately after the shedding of the old one during the final stages of the molting process. Its molecular identity as an approximately 30 kDa bioactive heterodimer consisting of two cystine knot proteins resisted elucidation for 43 years. The sequence of the two bursicon subunits is highly conserved among arthropods, and this conservation extends even to echinoderms. We review the efforts leading to bursicon's characterization, the identification of its leucine-rich repeat-containing, G protein-coupled receptor (LGR2), and the progress towards revealing its various functions. It is now clear that bursicon regulates different aspects of wing inflation in Drosophila melanogaster besides being involved at various points in the cuticle tanning process in different insects. We also describe the current knowledge of the expression of bursicon in the central nervous system of different insects in large homologous neurosecretory cells, and the changes in its expression during the development of Manduca sexta and D. melanogaster. Although much remains to be learned, the elucidation of its molecular identity and that of its receptor has provided the breakthrough needed for investigating the diverse actions of this critical insect neurohormone.
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Abstract
Neurons acquire their molecular, neurochemical, and connectional features during development as a result of complex regulatory mechanisms. Here, we show that a ubiquitous, multifunctional protein cofactor, Chip, plays a critical role in a set of neurons in Drosophila that control the well described posteclosion behavior. Newly eclosed flies normally expand their wings and display tanning and hardening of their cuticle. Using multiple approaches to interfere with Chip function, we find that these processes do not occur without normal activity of this protein. Furthermore, we identified the nature of the deficit to be an absence of Bursicon in the hemolymph of newly eclosed flies, whereas the responsivity to Bursicon in these flies remains normal. Chip interacts with transcription factors of the LIM-HD (LIM-homeodomain) family, and we identified one member, dIslet, as a potential partner of Chip in this process. Our findings provide the first evidence of transcriptional mechanisms involved in the development of the neuronal circuit that regulates posteclosion behavior in Drosophila.
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Wang S, An S, Song Q. Transcriptional expression of bursicon and novel bursicon-regulated genes in the house fly Musca domestica. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2008; 68:100-112. [PMID: 18454490 DOI: 10.1002/arch.20239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Bursicon is a neuropeptide that regulates cuticle sclerotization (hardening and tanning) via a G protein-coupled receptor. It consists of two subunits, an alpha and a beta. In the present study, we investigated the transcriptional expression and in situ localization of bursicon alpha and beta in the central nerve system of the house fly Musca domestica. Most importantly, we identified two novel bursicon-regulated genes using recombinant bursicon (rbursicon) heterodimer in a neck-ligated house fly assay. RT-PCR analysis revealed that both bursicon alpha and beta subunits were present in the central nerve system of larval and pupal stages, reached the maximal level in pharate adults, and declined sharply after adult emergence, suggesting the release of the hormone upon adult emergence. In situ localization of bursicon transcripts showed that both bursicon alpha and beta transcripts were expressed in a set of neurosecretory cells (NSCs) in the thoracic-abdominal ganglia of M. domestica. Two Drosophila melanogaster homologous genes, designated CG7985hh and CG30287hh, were up-regulated by rbursicon in a time-dependent manner and verified by real-time PCR, implying their involvement in the cuticle tanning process.
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Affiliation(s)
- Songjie Wang
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211, USA
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Dai L, Dewey EM, Zitnan D, Luo CW, Honegger HW, Adams ME. Identification, developmental expression, and functions of bursicon in the tobacco hawkmoth, Manduca sexta. J Comp Neurol 2008; 506:759-74. [PMID: 18076057 DOI: 10.1002/cne.21575] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During posteclosion, insects undergo sequential processes of wing expansion and cuticle tanning. Bursicon, a highly conserved neurohormone implicated in regulation of these processes, was characterized recently as a heterodimeric cystine knot protein in Drosophila melanogaster. Here we report the predicted precursor sequences of bursicon subunits (Masburs and Maspburs) in the moth Manduca sexta. Distinct developmental patterns of mRNA transcript and subunit-specific protein labeling of burs and pburs as well as crustacean cardioactive peptide in neurons of the ventral nervous system were observed in pharate larval, pupal, and adult stages. A subset of bursicon neurons located in thoracic ganglia of larvae expresses ecdysis-triggering hormone (ETH) receptors, suggesting that they are direct targets of ETH. Projections of bursicon neurons within the CNS and to neurohemal secretory sites are consistent with both central signaling and circulatory hormone functions. Intrinsic cells of the corpora cardiaca contain pburs transcripts and pburs-like immunoreactivity, whereas burs transcripts and burs-like immunoreactivity were absent in these cells. Recombinant bursicon induces both wing expansion and tanning, whereas synthetic eclosion hormone induces only wing expansion.
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Affiliation(s)
- Li Dai
- Department of Entomology and Cell Biology, University of California, Riverside 92521, USA
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Wilcockson DC, Webster SG. Identification and developmental expression of mRNAs encoding putative insect cuticle hardening hormone, bursicon in the green shore crab Carcinus maenas. Gen Comp Endocrinol 2008; 156:113-25. [PMID: 18221939 DOI: 10.1016/j.ygcen.2007.12.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 11/29/2007] [Accepted: 12/10/2007] [Indexed: 11/25/2022]
Abstract
Bursicon is the ultimate hormone in insect ecdysis, which is involved in cuticle hardening. Here we show that mRNAs encoding the heterodimeric cystine knot protein bursicon (Burs alpha, beta), are present in crustaceans, suggesting ubiquity of this hormone in arthropods. We firstly report the cloning, sequencing of mRNAs encoding subunits from the water flea, Daphnia arenata and the CNS of the crab, Carcinus maenas, in comparison with insect bursicon subunits. Expression patterns of alpha and beta burs mRNAs were examined by in-situ hybridisation (ISH) and quantitative RT-PCR. In the thoracic ganglion, burs alpha and beta mRNAs were completely colocalised in neurones expressing crustacean cardioactive peptide (CCAP). However, in the brain and eyestalk, bursicon transcripts were never observed, despite a complex expression pattern of CCAP interneurones. Patterns of expression of burs alpha and beta mRNAs were constitutive during the moult cycle of adult crabs, in stark contrast to the situation in insects. Whilst copy numbers of burs beta transcripts closely matched those of CCAP, those of burs alpha mRNA were around 3-fold higher than burs beta. This pattern was apparent during embryogenesis, where bursicon transcripts were first observed at around 50% development-the same time as first expression of CCAP mRNA. Transcript ratios (burs alpha: beta) increased during development. Our studies have shown, for the first time, that bursicon mRNAs are expressed in identified neurones in the nervous system of crustaceans. These findings will now promote further investigation into the functions of bursicon during the moult cycle and development of crustaceans.
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Affiliation(s)
- David C Wilcockson
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
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Van Loy T, Van Hiel MB, Vandersmissen HP, Poels J, Mendive F, Vassart G, Vanden Broeck J. Evolutionary conservation of bursicon in the animal kingdom. Gen Comp Endocrinol 2007; 153:59-63. [PMID: 17275819 DOI: 10.1016/j.ygcen.2006.12.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 11/16/2006] [Accepted: 12/18/2006] [Indexed: 11/27/2022]
Abstract
Bursicon bioactivity is essential for tanning of the exoskeleton and for wing spreading behavior that occur in newly emerged adult insects. Previously, we demonstrated that in the fruit fly, Drosophila melanogaster, bursicon exists as a heterodimeric cystine knot protein that activates the leucine-rich repeats containing G protein-coupled receptor 2 (DLGR2). By performing similarity based in silico searches in genomic and complementary DNA databases, we identified bursicon homologous sequences in several protostomian as well as deuterostomian invertebrates. In the genome of the honeybee, Apis mellifera, the coding regions for bursicon cystine knot subunits are organized in a genomic locus of approximately 4 kilobase pairs. Reverse transcription PCR analysis indicates that this region likely codes for two distinct bursicon cystine knot subunits. Our results illustrate the remarkable conservation of bursicon in invertebrate species and provide an avenue for functional analyses of this hormone in a wide range of animal species.
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Affiliation(s)
- Tom Van Loy
- Animal Physiology and Neurobiology, Laboratory for Developmental Physiology, Genomics and Proteomics, Zoological Institute, K.U.Leuven, Naamsestraat 59, B-3000, Belgium
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Zitnan D, Kim YJ, Zitnanová I, Roller L, Adams ME. Complex steroid-peptide-receptor cascade controls insect ecdysis. Gen Comp Endocrinol 2007; 153:88-96. [PMID: 17507015 PMCID: PMC4955941 DOI: 10.1016/j.ygcen.2007.04.002] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 03/22/2007] [Accepted: 04/01/2007] [Indexed: 11/29/2022]
Abstract
Insect ecdysis sequence is composed of pre-ecdysis, ecdysis and post-ecdysis behaviors controlled by a complex cascade of peptide hormones from endocrine Inka cells and neuropeptides in the central nervous system (CNS). Inka cells produce pre-ecdysis and ecdysis triggering hormones (ETH) which activate the ecdysis sequence through receptor-mediated actions on specific neurons in the CNS. Multiple experimental approaches have been used to determine mechanisms of ETH expression and release from Inka cells and its action on the CNS of moths and flies. During the preparatory phase 1-2 days prior to ecdysis, high ecdysteroid levels induce expression of ETH receptors in the CNS and increased ETH production in Inka cells, which coincides with expression of nuclear ecdysone receptor (EcR) and transcription factor cryptocephal (CRC). However, high ecdysteroid levels prevent ETH release from Inka cells. Acquisition of Inka cell competence to release ETH requires decline of ecdysteroid levels and beta-FTZ-F1 expression few hours prior to ecdysis. The behavioral phase is initiated by ETH secretion into the hemolymph, which is controlled by two brain neuropeptides-corazonin and eclosion hormone (EH). Corazonin acts on its receptor in Inka cells to elicit low level ETH secretion and initiation of pre-ecdysis, while EH induces cGMP-mediated ETH depletion and consequent activation of ecdysis. The activation of both behaviors is accomplished by ETH action on central neurons expressing ETH receptors A and B (ETHR-A and B). These neurons produce numerous excitatory or inhibitory neuropeptides which initiate or terminate different phases of the ecdysis sequence. Our data indicate that insect ecdysis is a very complex process characterized by two principal steps: (1) ecdysteroid-induced expression of receptors and transcription factors in the CNS and Inka cells. (2) Release and interaction of Inka cell peptide hormones and multiple central neuropeptides to control consecutive phases of the ecdysis sequence.
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Affiliation(s)
- D Zitnan
- Institute of Zoology, Slovak Academy of Sciences, Dubravska cesta 9, 84506 Bratislava, Slovakia.
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Luan H, Lemon WC, Peabody NC, Pohl JB, Zelensky PK, Wang D, Nitabach MN, Holmes TC, White BH. Functional dissection of a neuronal network required for cuticle tanning and wing expansion in Drosophila. J Neurosci 2006; 26:573-84. [PMID: 16407556 PMCID: PMC1857274 DOI: 10.1523/jneurosci.3916-05.2006] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A subset of Drosophila neurons that expresses crustacean cardioactive peptide (CCAP) has been shown previously to make the hormone bursicon, which is required for cuticle tanning and wing expansion after eclosion. Here we present evidence that CCAP-expressing neurons (NCCAP) consist of two functionally distinct groups, one of which releases bursicon into the hemolymph and the other of which regulates its release. The first group, which we call NCCAP-c929, includes 14 bursicon-expressing neurons of the abdominal ganglion that lie within the expression pattern of the enhancer-trap line c929-Gal4. We show that suppression of activity within this group blocks bursicon release into the hemolymph together with tanning and wing expansion. The second group, which we call NCCAP-R, consists of NCCAP neurons outside the c929-Gal4 pattern. Because suppression of synaptic transmission and protein kinase A (PKA) activity throughout NCCAP, but not in NCCAP-c929, also blocks tanning and wing expansion, we conclude that neurotransmission and PKA are required in NCCAP-R to regulate bursicon secretion from NCCAP-c929. Enhancement of electrical activity in NCCAP-R by expression of the bacterial sodium channel NaChBac also blocks tanning and wing expansion and leads to depletion of bursicon from central processes. NaChBac expression in NCCAP-c929 is without effect, suggesting that the abdominal bursicon-secreting neurons are likely to be silent until stimulated to release the hormone. Our results suggest that NCCAP form an interacting neuronal network responsible for the regulation and release of bursicon and suggest a model in which PKA-mediated stimulation of inputs to normally quiescent bursicon-expressing neurons activates release of the hormone.
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Affiliation(s)
- Haojiang Luan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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Ewer J. Behavioral actions of neuropeptides in invertebrates: insights from Drosophila. Horm Behav 2005; 48:418-29. [PMID: 15996666 DOI: 10.1016/j.yhbeh.2005.05.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Revised: 05/17/2005] [Accepted: 05/18/2005] [Indexed: 10/25/2022]
Abstract
This review discusses recent advances in our understanding of the hormonal control of ecdysis behavior in Drosophila, as well as methods that can more generally be used in this organism to investigate the in vivo function of neuropeptide hormones. Ecdysis is a dedicated, vital, behavior that is used by arthropods at the end of each molt to shed the remains of the old exoskeleton. It is under the control of several interacting neuropeptide hormones, and successful ecdysis requires that the behavior and accompanying peripheral events occur at a precise time and in the correct order. The tightly controlled timing and concatenation of these events are due to the complex hormonal control of ecdysis, with several neuropeptides contributing to a particular event, and, conversely, one neuropeptide effecting both central as well as peripheral actions. It is for the analyses of this type of behavior that Drosophila can provide unique insights, and some of these insights are summarized here. In addition, I discuss more generally approaches that are available in this organism, which make it especially useful for investigating the hormonal control of behavior.
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Affiliation(s)
- John Ewer
- Entomology Department, Cornell University, 5130 Comstock Hall, Ithaca, NY 14853, USA.
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Mendive FM, Van Loy T, Claeysen S, Poels J, Williamson M, Hauser F, Grimmelikhuijzen CJP, Vassart G, Vanden Broeck J. Drosophilamolting neurohormone bursicon is a heterodimer and the natural agonist of the orphan receptor DLGR2. FEBS Lett 2005; 579:2171-6. [PMID: 15811337 DOI: 10.1016/j.febslet.2005.03.006] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 03/02/2005] [Accepted: 03/02/2005] [Indexed: 10/25/2022]
Abstract
Bursicon is a neurohumoral agent responsible for tanning and hardening of the cuticle and expansion of the wings during the final phase of insect metamorphosis. Although the hormonal activity was described more than 40 years ago, the molecular nature of bursicon has remained elusive. We identify here Drosophila bioactive bursicon as a heterodimer made of two cystine knot polypeptides. This conclusion was reached in part from the unexpected observation that in the genome of the honey bee, the orthologs of the two Drosophila proteins are predicted to be fused in a single open reading frame. The heterodimeric Drosophila protein displays bursicon bioactivity in freshly enclosed neck-ligated flies and is the natural agonist of the orphan G protein-coupled receptor DLGR2.
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Affiliation(s)
- Fernando M Mendive
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, B-1070 Bruxelles, Belgium
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Luo CW, Dewey EM, Sudo S, Ewer J, Hsu SY, Honegger HW, Hsueh AJW. Bursicon, the insect cuticle-hardening hormone, is a heterodimeric cystine knot protein that activates G protein-coupled receptor LGR2. Proc Natl Acad Sci U S A 2005; 102:2820-5. [PMID: 15703293 PMCID: PMC549504 DOI: 10.1073/pnas.0409916102] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
All arthropods periodically molt to replace their exoskeleton (cuticle). Immediately after shedding the old cuticle, the neurohormone bursicon causes the hardening and darkening of the new cuticle. Here we show that bursicon, to our knowledge the first heterodimeric cystine knot hormone found in insects, consists of two proteins encoded by the genes burs and pburs (partner of burs). The pburs/burs heterodimer from Drosophila melanogaster binds with high affinity and specificity to activate the G protein-coupled receptor DLGR2, leading to the stimulation of cAMP signaling in vitro and tanning in neck-ligated blowflies. Native bursicon from Periplaneta americana is also a heterodimer. In D. melanogaster the levels of pburs, burs, and DLGR2 transcripts are increased before ecdysis, consistent with their role in postecdysial cuticle changes. Immunohistochemical analyses in diverse insect species revealed the colocalization of pburs- and burs-immunoreactivity in some of the neurosecretory neurons that also express crustacean cardioactive peptide. Forty-three years after its initial description, the elucidation of the molecular identity of bursicon and the verification of its receptor allow for studies of bursicon actions in regulating cuticle tanning, wing expansion, and as yet unknown functions. Because bursicon subunit genes are homologous to the vertebrate bone morphogenetic protein antagonists, our findings also facilitate investigation on the function of these proteins during vertebrate development.
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Affiliation(s)
- Ching-Wei Luo
- Division of Reproductive Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA 94305-5317, USA
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Honegger HW, Dewey EM, Kostron B. From bioassays to Drosophila genetics: strategies for characterizing an essential insect neurohormone, bursicon. ACTA BIOLOGICA HUNGARICA 2005; 55:91-102. [PMID: 15270222 DOI: 10.1556/abiol.55.2004.1-4.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe the molecular analysis and cellular expression of the insect peptide neurohormone, bursicon. Bursicon triggers the sclerotization of the soft insect cuticle after ecdysis. Using protein elution analyses from SDS gels, we determined the molecular weight of bursicon from different insects to be approximately 30 kDa. Four partial peptide sequences of Periplaneta americana bursicon were obtained from purified nerve cord homogenates separated on two-dimensional gels. Antibodies produced against one of the sequences identified the cellular location of bursicon in different insects and showed that bursicon is co-produced with crustacean cardioactive peptide (CCAP) in the same neurons in all insects tested so far. Additionally, using the partial peptide sequences, we successfully searched the Drosophila genome project for the gene encoding bursicon. With Drosophila as a tool, we can now verify the function of the sequence using transgenic flies. Sequence comparisons also allowed us to verify that bursicon is conserved, corroborating the older data from bioassays and immunohistochemical analyses. The sequence of bursicon will enable further analysis of its function, release, and evolution.
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Affiliation(s)
- H W Honegger
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
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Truman JW. Hormonal Control of Insect Ecdysis: Endocrine Cascades for Coordinating Behavior with Physiology. VITAMINS & HORMONES 2005; 73:1-30. [PMID: 16399406 DOI: 10.1016/s0083-6729(05)73001-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- James W Truman
- Department of Biology, University of Washington, Seattle, Washington 98195, USA
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Dewey EM, McNabb SL, Ewer J, Kuo GR, Takanishi CL, Truman JW, Honegger HW. Identification of the gene encoding bursicon, an insect neuropeptide responsible for cuticle sclerotization and wing spreading. Curr Biol 2004; 14:1208-13. [PMID: 15242619 DOI: 10.1016/j.cub.2004.06.051] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 05/25/2004] [Accepted: 05/25/2004] [Indexed: 10/26/2022]
Abstract
To accommodate growth, insects must periodically replace their exoskeletons. After shedding the old cuticle, the new soft cuticle must sclerotize. Sclerotization has long been known to be controlled by the neuropeptide hormone bursicon, but its large size of 30 kDa has frustrated attempts to determine its sequence and structure. Using partial sequences obtained from purified cockroach bursicon, we identified the Drosophila melanogaster gene CG13419 as a candidate bursicon gene. CG13419 encodes a peptide with a predicted final molecular weight of 15 kDa, which likely functions as a dimer. This predicted bursicon protein belongs to the cystine knot family, which includes vertebrate transforming growth factor-beta (TGF-beta) and glycoprotein hormones. Point mutations in the bursicon gene cause defects in cuticle sclerotization and wing expansion behavior. Bioassays show that these mutants have decreased bursicon bioactivity. In situ hybridization and immunocytochemistry revealed that bursicon is co-expressed with crustacean cardioactive peptide (CCAP). Transgenic flies that lack CCAP neurons also lacked bursicon bioactivity. Our results indicate that CG13419 encodes bursicon, the last of the classic set of insect developmental hormones. It is the first member of the cystine knot family to have a defined function in invertebrates. Mutants show that the spectrum of bursicon actions is broader than formerly demonstrated.
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Affiliation(s)
- Elizabeth M Dewey
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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Meeusen T, Mertens I, De Loof A, Schoofs L. G Protein-Coupled Receptors in Invertebrates: A State of the Art. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 230:189-261. [PMID: 14692683 DOI: 10.1016/s0074-7696(03)30004-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute one of the largest and most ancient superfamilies of membrane-spanning proteins. We focus on neuropeptide GPCRs, in particular on those of invertebrates. In general, such receptors mediate the responses of signaling molecules that constitute the highest hierarchical position in the regulation of physiological processes. Until recently, only a few of these receptors were identified in invertebrates. However, the availability of a plethora of genomic information has boosted the discovery of novel members in several invertebrate species, such as Drosophila, in which 18 neuropeptide GPCRs have been characterized. The finalization of genomic projects in other invertebrates will lead to a similar expansion of GPCR understanding. Many new insights regarding neuropeptide regulation have followed from the discovery of their cognate receptors. Furthermore, information on GPCR signaling is still fragmentary and the elucidation of these pathways in model insects such as Drosophila will lead to further insights in other species, including mammals. In this review we present the current status of what is known about invertebrate GPCRs, discuss some novel perceptions that follow from the identified members, and, finally, present some future prospects.
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Affiliation(s)
- Tom Meeusen
- Laboratory of Developmental Physiology, Genomics, and Proteomics, K.U. Leuven, B-3000 Leuven, Belgium
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Abstract
The extremely large number of insects and members of allied groups alive today suggests that molting--shedding of an old cuticle--may be one of the most commonly performed behaviors on our planet. Removal of an old cuticle in insects is associated with stereotyped, species-specific patterns of behavior referred to as ecdysis. It has been recognized for decades that the initiation of ecdysis is under hormonal control, but until recently many of the key peptides that regulate ecdysis were unknown. The report in 1996 of a new ecdysis-triggering hormone (ETH) sparked an era of significant advances in our understanding of the regulation of molting. This article summarizes the current model of peptide regulation of ecdysis, a model that is based on a positive feedback loop between ETH and a brain peptide, eclosion hormone. Then the relationship of these regulatory peptides to the neural circuitry that is the ultimate driver of the behavior are described. Because insects can undergo both status quo (larval-larval) and metamorphic (larval-pupal and pupal-adult) molts, differences in ecdysis behavior at different life stages are described and potential sources of these differences are identified. Most of the work described is based on studies of ecdysis in the hawkmoth, Manduca sexta, but results from studies of ecdysis in the fruit fly Drosophila melanogaster are also discussed.
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Affiliation(s)
- Karen A Mesce
- Department of Entomology, University of Minnesota, St. Paul, Minnesota 55108, USA
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