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Marchal E, Vandersmissen HP, Badisco L, Van de Velde S, Verlinden H, Iga M, Van Wielendaele P, Huybrechts R, Simonet G, Smagghe G, Vanden Broeck J. Control of ecdysteroidogenesis in prothoracic glands of insects: a review. Peptides 2010; 31:506-19. [PMID: 19723550 DOI: 10.1016/j.peptides.2009.08.020] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 08/21/2009] [Accepted: 08/21/2009] [Indexed: 01/13/2023]
Abstract
The very first step in the study of the endocrine control of insect molting was taken in 1922. Stefan Kopec characterized a factor in the brain of the gypsy moth, Lymantria dispar which appeared to be essential for metamorphosis. This factor was later identified as the neuropeptide prothoracicotropic hormone (PTTH), the first discovery of a series of factors involved in the regulation of ecdysteroid biosynthesis in insects. It is now accepted that PTTH is the most important regulator of prothoracic gland (PG) ecdysteroidogenesis. The periodic increases in ecdysteroid titer necessary for insect development can basically be explained by the episodic activation of the PGs by PTTH. However, since the characterization of the prothoracicostatic hormone (PTSH), it has become clear that in addition to 'tropic factors', also 'static factors', which are responsible for the 'fine-tuning' of the hemolymph ecdysteroid titer, are at play. Many of these regulatory factors are peptides originating from the brain, but also other, extracerebral factors both of peptidic and non-peptidic nature are able to affect PG ecdysteroidogenesis, such as the 'classic' insect hormones, juvenile hormone (JH) and the molting hormone (20E) itself. The complex secretory pattern of ecdysteroids as observed in vivo is the result of the delicate balance and interplay between these ecdysiotropic and ecdysiostatic factors.
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Affiliation(s)
- Elisabeth Marchal
- Department of Animal Physiology and Neurobiology, K.U. Leuven, Naamsestraat 59, 3000 Leuven, Belgium
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Simo L, Zitnan D, Park Y. Two novel neuropeptides in innervation of the salivary glands of the black-legged tick, Ixodes scapularis: myoinhibitory peptide and SIFamide. J Comp Neurol 2010; 517:551-63. [PMID: 19824085 DOI: 10.1002/cne.22182] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The peptidergic signaling system is an ancient cell-cell communication mechanism that is involved in numerous behavioral and physiological events in multicellular organisms. We identified two novel neuropeptides in the neuronal projections innervating the salivary glands of the black-legged tick, Ixodes scapularis (Say, 1821). Myoinhibitory peptide (MIP) and SIFamide immunoreactivities were colocalized in the protocerebral cells and their projections terminating on specific cells of salivary gland acini (types II and III). Immunoreactive substances were identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis: a 1,321.6-Da peptide with the sequence typical for MIP (ASDWNRLSGMWamide) and a 1,395.7-Da SIFamide (AYRKPPFNGSIFamide), which are highly conserved among arthropods. Genes encoding these peptides were identified in the available Ixodes genome and expressed sequence tag (EST) database. In addition, the cDNA encoding the MIP prepropeptide was isolated by rapid amplification of cDNA ends (RACE). In this report, we describe the anatomical structure of specific central neurons innervating salivary gland acini and identify different neuropeptides and their precursors expressed by these neurons. Our data provide evidence for neural control of salivary gland by MIP and SIFamide from the synganglion, thus leading a basis for functional studies of these two distinct classes of neuropeptides.
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Affiliation(s)
- Ladislav Simo
- Department of Entomology, Kansas State University, Manhattan, Kansas 66506-4004, USA
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Bombyx prothoracicostatic peptides activate the sex peptide receptor to regulate ecdysteroid biosynthesis. Proc Natl Acad Sci U S A 2010; 107:2060-5. [PMID: 20133850 DOI: 10.1073/pnas.0907471107] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Insect molting and metamorphosis are induced by steroid hormones named ecdysteroids, whose production is regulated by various neuropeptides. We cloned the gene and analyzed the expression of the prothoracicostatic peptide, a unique neuropeptide shown to suppress the production of ecdysteroids in the prothoracic gland of the silkworm, Bombyx mori. We also characterized a Bombyx G protein-coupled receptor, which has previously been identified as an ortholog of the Drosophila sex peptide receptor, as a functional prothoracicostatic peptide receptor. This receptor responded specifically to the prothoracicostatic peptides when examined using a heterologous expression system. The receptor was highly expressed in the prothoracic gland on the day before each larval and pupal ecdysis, when prothoracicostatic peptides are synthesized at a high level in the epiproctodeal glands. These results suggest that the sex peptide receptor functions as a prothoracicostatic peptide receptor in Bombyx and that the peripheral neurosecretory cells as well as the central neuroendocrine system play stage-specific roles in regulating ecdysteroidogenesis.
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54
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Neuropeptide Receptors as Possible Targets for Development of Insect Pest Control Agents. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 692:211-26. [DOI: 10.1007/978-1-4419-6902-6_11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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55
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NICHOLS RUTHANN, BENDENA WILLIAMG, TOBE STEPHENS. Myotropic Peptides in Drosophila Melanogaster And The Genes That Encode Them. J Neurogenet 2009. [DOI: 10.1080/01677060290024592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- RUTHANN NICHOLS
- Biological Chemistry Department, University of Michigan, Ann Arbor, MI 48109
| | | | - STEPHEN S. TOBE
- Zoology Department, University of Toronto, Toronto, ON M5S 3G5, Canada
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56
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Comparison of Caenorhabditis elegans NLP peptides with arthropod neuropeptides. Trends Parasitol 2009; 25:171-81. [DOI: 10.1016/j.pt.2008.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 11/25/2008] [Accepted: 12/19/2008] [Indexed: 01/26/2023]
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57
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Husson SJ, Landuyt B, Nys T, Baggerman G, Boonen K, Clynen E, Lindemans M, Janssen T, Schoofs L. Comparative peptidomics of Caenorhabditis elegans versus C. briggsae by LC-MALDI-TOF MS. Peptides 2009; 30:449-57. [PMID: 18760316 DOI: 10.1016/j.peptides.2008.07.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 07/30/2008] [Accepted: 07/30/2008] [Indexed: 11/21/2022]
Abstract
Neuropeptides are important signaling molecules that function in cell-cell communication as neurotransmitters or hormones to orchestrate a wide variety of physiological conditions and behaviors. These endogenous peptides can be monitored by high throughput peptidomics technologies from virtually any tissue or organism. The neuropeptide complement of the soil nematode Caenorhabditis elegans has been characterized by on-line two-dimensional liquid chromatography and quadrupole time-of-flight tandem mass spectrometry (2D-nanoLC Q-TOF MS/MS). Here, we use an alternative peptidomics approach combining liquid chromatography (LC) with matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry to map the peptide content of C. elegans and another Caenorhabditis species, Caenorhabditis briggsae. This study allows a better annotation of neuropeptide-encoding genes from the C. briggsae genome and provides a promising basis for further evolutionary comparisons.
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Affiliation(s)
- Steven J Husson
- Functional Genomics and Proteomics Unit, Department of Biology, K.U.Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
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58
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Proteomic identification of the silkworm (Bombyx mori L) prothoracic glands during the fifth instar stage. Biosci Rep 2009; 29:121-9. [DOI: 10.1042/bsr20080076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Although the ecdysteroid of the silkworm had been studied for decades, the proteome of the prothoracic gland, the primary source of ecdysteroid hormones, has not been studied previously. In the present paper, we utilized a proteomic approach to investigate the fifth instar prothoracic gland during the growth and development of the silkworm, Bombyx mori L. The two-dimensional electrophoresis results showed that the majority of proteins were acidic proteins, especially concentrated in the area of 25–65 kDa, with pI values of between 4 and 7, and the difference was not distinct. When compared with Qiufeng (Japanese strain), the interspecific distinction was larger than the intraspecific distinction, and 19 particular spots, excized from the third, fifth and ninth days of p50 (Chinese strain) and Qiufeng were subjected to MALDI-TOF–MS (matrix-assisted laser-desorption ionization–time-of-flight MS) analysis. We sorted them into seven catagories: energetics and/or metabolism, storage proteins, protection, lipid metabolism, signal transduction, cell function and unknown function proteins. Of these proteins, arginine methyltransferase is discussed as playing an important role in regulating the activation of ecdysteroidogenesis via transcription or translation.
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59
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Regulatory peptides in fruit fly midgut. Cell Tissue Res 2008; 334:499-516. [PMID: 18972134 DOI: 10.1007/s00441-008-0708-3] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 09/19/2008] [Indexed: 10/21/2022]
Abstract
Regulatory peptides were immunolocalized in the midgut of the fruit fly Drosophila melanogaster. Endocrine cells were found to produce six different peptides: allatostatins A, B and C, neuropeptide F, diuretic hormone 31, and the tachykinins. Small neuropeptide-F (sNPF) was found in neurons in the hypocerebral ganglion innervating the anterior midgut, whereas pigment-dispersing factor was found in nerves on the most posterior part of the posterior midgut. Neuropeptide-F (NPF)-producing endocrine cells were located in the anterior and middle midgut and in the very first part of the posterior midgut. All NPF endocrine cells also produced tachykinins. Endocrine cells containing diuretic hormone 31 were found in the caudal half of the posterior midgut; these cells also produced tachykinins. Other endocrine cells produced exclusively tachykinins in the anterior and posterior extemities of the midgut. Allatostatin-immunoreactive endocrine cells were present throughout the midgut. Those in the caudal half of the posterior midgut produced allatostatins A, whereas those in the anterior, middle, and first half of the posterior midgut produced allatostatin C. In the middle of the posterior midgut, some endocrine cells produced both allatostatins A and C. Allatostatin-C-immunoreactive endocrine cells were particularly prominent in the first half of the posterior midgut. Allatostatin B/MIP-immunoreactive cells were not consistently found and, when present, were only weakly immunoreactive, forming a subgroup of the allatostatin-C-immunoreactive cells in the posterior midgut. Previous work on Drosophila and other insect species suggested that (FM)RFamide-immunoreactive endocrine cells in the insect midgut could produce NPF, sNPF, myosuppressin, and/or sulfakinins. Using a combination of specific antisera to these peptides and transgenic fly models, we showed that the endocrine cells in the adult Drosophila midgut produced exclusively NPF. Although the Drosophila insulin gene Ilp3 was abundantly expressed in the midgut, Ilp3 was not expressed in endocrine cells, but in midgut muscle.
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60
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Hauser F, Cazzamali G, Williamson M, Park Y, Li B, Tanaka Y, Predel R, Neupert S, Schachtner J, Verleyen P, Grimmelikhuijzen CJP. A genome-wide inventory of neurohormone GPCRs in the red flour beetle Tribolium castaneum. Front Neuroendocrinol 2008; 29:142-65. [PMID: 18054377 DOI: 10.1016/j.yfrne.2007.10.003] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 10/16/2007] [Accepted: 10/17/2007] [Indexed: 01/01/2023]
Abstract
Insect neurohormones (biogenic amines, neuropeptides, and protein hormones) and their G protein-coupled receptors (GPCRs) play a central role in the control of behavior, reproduction, development, feeding and many other physiological processes. The recent completion of several insect genome projects has enabled us to obtain a complete inventory of neurohormone GPCRs in these insects and, by a comparative genomics approach, to analyze the evolution of these proteins. The red flour beetle Tribolium castaneum is the latest addition to the list of insects with a sequenced genome and the first coleopteran (beetle) to be sequenced. Coleoptera is the largest insect order and about 30% of all animal species living on earth are coleopterans. Some coleopterans are severe agricultural pests, which is also true for T. castaneum, a global pest for stored grain and other dried commodities for human consumption. In addition, T. castaneum is a model for insect development. Here, we have investigated the presence of neurohormone GPCRs in Tribolium and compared them with those from the fruit fly Drosophila melanogaster (Diptera) and the honey bee Apis mellifera (Hymenoptera). We found 20 biogenic amine GPCRs in Tribolium (21 in Drosophila; 19 in the honey bee), 48 neuropeptide GPCRs (45 in Drosophila; 35 in the honey bee), and 4 protein hormone GPCRs (4 in Drosophila; 2 in the honey bee). Furthermore, we identified the likely ligands for 45 of these 72 Tribolium GPCRs. A highly interesting finding in Tribolium was the occurrence of a vasopressin GPCR and a vasopressin peptide. So far, the vasopressin/GPCR couple has not been detected in any other insect with a sequenced genome (D. melanogaster and six other Drosophila species, Anopheles gambiae, Aedes aegypti, Bombyx mori, and A. mellifera). Tribolium lives in very dry environments. Vasopressin in mammals is the major neurohormone steering water reabsorption in the kidneys. Its presence in Tribolium, therefore, might be related to the animal's need to effectively control water reabsorption. Other striking differences between Tribolium and the other two insects are the absence of the allatostatin-A, kinin, and corazonin neuropeptide/receptor couples and the duplications of other hormonal systems. Our survey of 340 million years of insect neurohormone GPCR evolution shows that neuropeptide/receptor couples can easily duplicate or disappear during insect evolution. It also shows that Drosophila is not a good representative of all insects, because several of the hormonal systems that we now find in Tribolium do not exist in Drosophila.
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Affiliation(s)
- Frank Hauser
- Center for Functional and Comparative Insect Genomics; and Department of Cell Biology and Comparative Zoology, Institute of Biology, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
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61
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De Loof A. Ecdysteroids, juvenile hormone and insect neuropeptides: Recent successes and remaining major challenges. Gen Comp Endocrinol 2008; 155:3-13. [PMID: 17716674 DOI: 10.1016/j.ygcen.2007.07.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 07/02/2007] [Accepted: 07/04/2007] [Indexed: 11/21/2022]
Abstract
In the recent decade, tremendous progress has been realized in insect endocrinology as the result of the application of a variety of advanced methods in neuropeptidome- and receptor research. Hormones of which the existence had been shown by bioassays four decades ago, e.g. bursicon (a member of the glycoprotein hormone family) and pupariation factor (Neb-pyrokinin 2, a myotropin), could be identified, along with their respective receptors. In control of diurnal rhythms, clock genes got company from the neuropeptide Pigment Dispersing Factor (PDF), of which the receptor could also be identified. The discovery of Inka cells and their function in metamorphosis was a true hallmark. Analysis of the genomes of Caenorhabditis elegans, Drosophila melanogaster and Apis mellifera yielded about 75, 100 and 200 genes coding for putative signaling peptides, respectively, corresponding to approximately 57, 100 and 100 peptides of which the expression could already be proven by means of mass spectrometry. The comparative approach invertebrates-vertebrates recently yielded indications for the existence of counterparts in insects for prolactin, atrial natriuretic hormone and Growth Hormone Releasing Hormone (GRH). Substantial progress has been realized in identifying the Halloween genes, a membrane receptor(s) for ecdysteroids, a nuclear receptor for methylfarnesoate, and dozens of GPCRs for insect neuropeptides. The major remaining challenges concern the making match numerous orphan GPCRs with orphan peptidic ligands, and elucidating their functions. Furthermore, the endocrine control of growth, feeding-digestion, and of sexual differentiation, in particular of males, is still poorly understood. The finding that the prothoracic glands produce an autocrine factor with growth factor-like properties and secrete proteins necessitates a reevaluation of their role in development.
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Affiliation(s)
- Arnold De Loof
- Zoological Institute of the Katholieke Universiteit Leuven, Naamsestraat 59, 3000 Leuven, Belgium
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62
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Mirth CK, Riddiford LM. Size assessment and growth control: how adult size is determined in insects. Bioessays 2007; 29:344-55. [PMID: 17373657 DOI: 10.1002/bies.20552] [Citation(s) in RCA: 268] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Size control depends on both the regulation of growth rate and the control over when to stop growing. Studies of Drosophila melanogaster have shown that insulin and Target of Rapamycin (TOR) pathways play principal roles in controlling nutrition-dependent growth rates. A TOR-mediated nutrient sensor in the fat body detects nutrient availability, and regulates insulin signaling in peripheral tissues, which in turn controls larval growth rates. After larvae initiate metamorphosis, growth stops. For growth to stop at the correct time, larvae need to surpass a critical weight. Recently, it was found that the insulin-dependent growth of the prothoracic gland is involved in assessing when critical weight has been reached. Furthermore, mutations in DHR4, a repressor of ecdysone signaling, reduce critical weight and adult size. Thus, the mechanisms that control growth rates converge on those assessing size to ensure that the larvae attain the appropriate size at metamorphosis.
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63
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Husson SJ, Mertens I, Janssen T, Lindemans M, Schoofs L. Neuropeptidergic signaling in the nematode Caenorhabditis elegans. Prog Neurobiol 2007; 82:33-55. [PMID: 17383075 DOI: 10.1016/j.pneurobio.2007.01.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 12/14/2006] [Accepted: 01/29/2007] [Indexed: 11/25/2022]
Abstract
The nematode Caenorhabditis elegans joins the menagerie of behavioral model systems next to the fruit fly Drosophila melanogaster, the marine snail Aplysia californica and the mouse. In contrast to Aplysia, which contains 20,000 neurons having cell bodies of hundreds of microns in diameter, C. elegans harbors only 302 tiny neurons from which the cell lineage is completely described, as is the case for all the other somatic cells. As such, this nervous system appears at first sight incommensurable with those of higher organisms, although genome-wide comparison of predicted C. elegans genes with their counterparts in vertebrates revealed many parallels. Together with its short lifespan and ease of cultivation, suitability for high-throughput genetic screenings and genome-wide RNA interference approaches, access to an advanced genetic toolkit and cell-ablation techniques, it seems that this tiny transparent organism of only 1mm in length has nothing to hide. Recently, highly exciting developments have occurred within the field of neuropeptidergic signaling in C. elegans, not only because of the availability of a sequenced genome since 1998, but especially because of state of the art post genomic technologies, that allow for molecular characterization of the signaling molecules. Here, we will focus on endogenous, bioactive (neuro)peptides and mainly discuss biosynthesis, peptide sequence information, localization and G-protein coupled receptors of the three major peptide families in C. elegans.
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Affiliation(s)
- Steven J Husson
- Functional Genomics and Proteomics Unit, Department of Biology, Katholieke Universiteit Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
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64
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Fu Q, Tang LS, Marder E, Li L. Mass spectrometric characterization and physiological actions of VPNDWAHFRGSWamide, a novel B type allatostatin in the crab, Cancer borealis. J Neurochem 2007; 101:1099-107. [PMID: 17394556 DOI: 10.1111/j.1471-4159.2007.04482.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The neural networks in the crustacean stomatogastric ganglion are modulated by neuroactive substances released locally into the neuropil of the stomatogastric ganglion and by circulating hormones released by neuroendocrine structures including the pericardial organs. Using nanoscale liquid chromatography coupled to electrospray ionization quadrupole-time-of-flight mass spectrometry, we have identified and sequenced a novel B type allatostatin (CbAST-B1), VPNDWAHFRGSWamide, present in the pericardial organs of the crabs, Cancer borealis, and Cancer productus. We describe the physiological actions of CbAST-B1 on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. CbAST-B1 reduces the pyloric network frequency in a dose-dependent manner. The effect of bath-applied CbAST-B1 depends on the preceding physiological state of the preparation. Surprisingly, despite marked amino-acid sequence dissimilarity between the novel CbAST-B1 and the A type allatostatin family of peptides (AST-A), the physiological effects of CbAST-B1 are similar to those of AST-A.
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Affiliation(s)
- Qiang Fu
- School of Pharmacy and Department of Chemistry, University of Wisconsin, Madison, WI 53705-2222, USA
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65
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Stay B, Tobe SS. The role of allatostatins in juvenile hormone synthesis in insects and crustaceans. ANNUAL REVIEW OF ENTOMOLOGY 2007; 52:277-99. [PMID: 16968202 DOI: 10.1146/annurev.ento.51.110104.151050] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Allatostatins are pleiotropic neuropeptides for which one function in insects is the inhibition of juvenile hormone synthesis. Juvenile hormone, an important regulator of development and reproduction in insects, is produced by the corpora allata. Mandibular organs, the crustacean homologs of insect corpora allata, produce precursors of juvenile hormone with putatively similar functions. Three types of allatostatins in insects have been isolated: FGLamides, W(X)(6)Wamides, and PISCFs. All act rapidly and reversibly; however, although these types occur in all groups of insects studied, they act as inhibitors of juvenile hormone production in only some groups. Only the FGLamide-type peptides have been isolated in crustaceans, in which they may function to stimulate production of hormone by the mandibular glands, as occurs in early cockroach embryos. Much remains to be learned in order to understand the role of allatostatins in the modulation of hormone production.
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Affiliation(s)
- Barbara Stay
- Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242-1911, USA.
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66
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Hossain M, Shimizu S, Fujiwara H, Sakurai S, Iwami M. EcR expression in the prothoracicotropic hormone-producing neurosecretory cells of the Bombyx mori brain. FEBS J 2006; 273:3861-8. [PMID: 16911531 DOI: 10.1111/j.1742-4658.2006.05398.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis through binding with a heterodimer of two nuclear receptors, the ecdysone receptor (EcR) and ultraspiracle (USP). Expression of the specific isoforms EcR-A and EcR-B1 governs steroid-induced responses in the developing cells of the silkworm Bombyx mori. Here, analysis of EcR-A and EcR-B1 expression during larval-pupal development showed that both genes were up-regulated by 20E in the B. mori brain. Whole-mount in situ hybridization and immunohistochemistry revealed that EcR-A and EcR-B1 mRNAs and proteins were exclusively located in two pairs of lateral neurosecretory cells in the larval brain known as the prothoracicotropic hormone (PTTH)- producing cells (PTPCs). In the pupal brain, EcR-A and EcR-B1 expression was detected in tritocerebral cells and optic lobe cells in addition to PTPCs. As PTTH controls ecdysone secretion by the prothoracic gland, these results indicate that 20E-responsive PTPCs are the master cells of insect metamorphosis.
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Affiliation(s)
- Monwar Hossain
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
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67
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Yamanaka N, Žitňan D, Kim YJ, Adams ME, Hua YJ, Suzuki Y, Suzuki M, Suzuki A, Satake H, Mizoguchi A, Asaoka K, Tanaka Y, Kataoka H. Regulation of insect steroid hormone biosynthesis by innervating peptidergic neurons. Proc Natl Acad Sci U S A 2006; 103:8622-7. [PMID: 16707581 PMCID: PMC1482630 DOI: 10.1073/pnas.0511196103] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In insects, steroid hormones named ecdysteroids elicit molting and metamorphosis. The prothoracic gland (PG) is a predominant source of ecdysteroids, where their biosynthesis (ecdysteroidogenesis) is regulated by several neuropeptides. Here, we report that FMRFamide-related peptides (FaRPs) regulate ecdysteroidogenesis through direct innervation of the PG in the silkworm Bombyx mori. We purified a previously uncharacterized Bombyx FaRP, DPSFIRFamide, and identified the corresponding Bombyx FMRFamide gene (Bommo-FMRFamide, BRFa), which encodes three additional FaRPs. All BRFa peptides suppressed ecdysteroidogenesis in the PG by reducing cAMP production by means of the receptor for Bommo-myosuppressin, another FaRP we have previously shown to act as a prothoracicostatic factor. BRFa is predominantly expressed in neurosecretory cells of thoracic ganglia, and the neurons in the prothoracic ganglion innervate the PG to supply all four peptides to the gland surface. Electrophysiological recordings during development confirmed the increased firing activity of BRFa neurons in stages with low PG activity and decreased ecdysteroid levels in the hemolymph. To our knowledge, this study provides the first report of peptides controlling ecdysteroidogenesis by direct innervation.
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Affiliation(s)
- Naoki Yamanaka
- *Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8562, Japan
| | - Dušan Žitňan
- Institute of Zoology, Slovak Academy of Sciences, Dúbravská cesta 9, 84206 Bratislava, Slovakia
| | - Young-Joon Kim
- Departments of Entomology and Cell Biology and Neuroscience, University of California, 5429 Boyce Hall, Riverside, CA 92521
| | - Michael E. Adams
- Departments of Entomology and Cell Biology and Neuroscience, University of California, 5429 Boyce Hall, Riverside, CA 92521
| | - Yue-Jin Hua
- Institute of Nuclear-Agricultural Science, Zhejiang University, Zhejiang 310029, China
| | - Yusuke Suzuki
- Frontier Research System, RIKEN, Saitama 351-0198, Japan
| | - Minoru Suzuki
- Frontier Research System, RIKEN, Saitama 351-0198, Japan
| | - Akemi Suzuki
- Frontier Research System, RIKEN, Saitama 351-0198, Japan
| | - Honoo Satake
- Suntory Institute for Bioorganic Research, Osaka 618-8503, Japan
| | - Akira Mizoguchi
- **Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan; and Laboratories of
| | | | - Yoshiaki Tanaka
- Insect Growth Regulation, National Institute of Agrobiological Science, Ibaraki 305-8634, Japan
| | - Hiroshi Kataoka
- *Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8562, Japan
- To whom correspondence should be addressed. E-mail:
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68
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Nagata S, Kataoka H, Suzuki A. Silk Moth Neuropeptide Hormones: Prothoracicotropic Hormone and Others. Ann N Y Acad Sci 2006; 1040:38-52. [PMID: 15891004 DOI: 10.1196/annals.1327.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The silkworm, Bombyx mori, is a very useful model species, especially in genetics, biochemistry, physiology, and molecular biology, helping researchers unravel the many mysteries involved in the insect life process. The present review describes our early contributions as chemists to the study of the molting and metamorphosis of B. mori. We also present research by Japanese scientists that contributed to the isolation and characterization of peptide hormones from B. mori.
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Affiliation(s)
- Shinji Nagata
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Japan
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69
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Namiki T, Niwa R, Sakudoh T, Shirai KI, Takeuchi H, Kataoka H. Cytochrome P450 CYP307A1/Spook: A regulator for ecdysone synthesis in insects. Biochem Biophys Res Commun 2005; 337:367-74. [PMID: 16188237 DOI: 10.1016/j.bbrc.2005.09.043] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Accepted: 09/03/2005] [Indexed: 11/26/2022]
Abstract
The prothoracic gland (PG) has essential roles in synthesizing and secreting a steroid hormone called ecdysone that is critical for molting and metamorphosis of insects. However, little is known about the genes controlling ecdysteroidogenesis in the PG. To identify genes functioning in the PG of the silkworm, Bombyx mori, we used differential display PCR and focused on a cytochrome P450 gene designated Cyp307a1. Its expression level positively correlates with a change in the hemolymph ecdysteroid titer. In addition, Drosophila Cyp307a1 is encoded in the spook locus, one of the Halloween mutant family members showing a low ecdysone titer in vivo, suggesting that Cyp307a1 is involved in ecdysone synthesis. While Drosophila Cyp307a1 is expressed in the early embryos and adult ovaries, the expression is not observed in the PGs of embryos or third instar larvae. These results suggest a difference in the ecdysone synthesis pathways during larval development in these insects.
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Affiliation(s)
- Toshiki Namiki
- Department of Integrated Biosciences, Rm. 201, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
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70
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Niwa R, Sakudoh T, Namiki T, Saida K, Fujimoto Y, Kataoka H. The ecdysteroidogenic P450 Cyp302a1/disembodied from the silkworm, Bombyx mori, is transcriptionally regulated by prothoracicotropic hormone. INSECT MOLECULAR BIOLOGY 2005; 14:563-71. [PMID: 16164612 DOI: 10.1111/j.1365-2583.2005.00587.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
During larval and pupal development of insects, ecdysone is synthesized in the prothoracic gland (PG). Although several Drosophila genes, including Halloween P450 genes, are known to be important for ecdysteroidogenesis in PG, little is known of the ecdysteroidogenic genes in other insects. Here we report on Cyp302a1/disembodied (dib-Bm), one of the Halloween P450s in the silkworm Bombyx mori that is a carbon-22 hydroxylase. dib-Bm is predominantly expressed in PG and its developmental expression profile is correlated with a change in the ecdysteroid titre in the haemolymph. Furthermore, dib-Bm expression in cultured PGs is significantly induced by treatment with prothoracicotropic hormone. This is the first report on the transcriptional induction of a steroidogenic gene by the tropic hormone in insects.
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Affiliation(s)
- R Niwa
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan.
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71
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Husson SJ, Clynen E, Baggerman G, De Loof A, Schoofs L. Discovering neuropeptides in Caenorhabditis elegans by two dimensional liquid chromatography and mass spectrometry. Biochem Biophys Res Commun 2005; 335:76-86. [PMID: 16061202 DOI: 10.1016/j.bbrc.2005.07.044] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2005] [Accepted: 07/13/2005] [Indexed: 10/25/2022]
Abstract
Completion of the Caenorhabditis elegans genome sequencing project in 1998 has provided more insight into the complexity of nematode neuropeptide signaling. Several C. elegans neuropeptide precursor genes, coding for approximately 250 peptides, have been predicted from the genomic database. One can, however, not deduce whether all these peptides are actually expressed, nor is it possible to predict all post-translational modifications. Using two dimensional nanoscale liquid chromatography combined with tandem mass spectrometry and database mining, we analyzed a mixed stage C. elegans extract. This peptidomic setup yielded 21 peptides derived from formerly predicted neuropeptide-like protein (NLP) precursors and 28 predicted FMRFamide-related peptides. In addition, we were able to sequence 11 entirely novel peptides derived from nine peptide precursors that were not predicted or identified in any way previously. Some of the identified peptides display profound sequence similarities with neuropeptides from other invertebrates, indicating that these peptides have a long evolutionary history.
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Affiliation(s)
- Steven J Husson
- Laboratory of Developmental Physiology, Genomics and Proteomics, Zoological Institute, Katholieke Universiteit Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
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72
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Yamanaka N, Hua YJ, Mizoguchi A, Watanabe K, Niwa R, Tanaka Y, Kataoka H. Identification of a novel prothoracicostatic hormone and its receptor in the silkworm Bombyx mori. J Biol Chem 2005; 280:14684-90. [PMID: 15701625 DOI: 10.1074/jbc.m500308200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The insect brain regulates the activity of the prothoracic glands to secrete ecdysteroids, which affect growth, molting, and metamorphosis. Here we report the identification of a novel prothoracicostatic factor and its receptor in the silkworm Bombyx mori. The prothoracicostatic factor purified from pupal brains of B. mori is a decapeptide with the conserved structure of an insect myosuppressin and thus named Bommo-myosuppressin. Bommo-myosuppressin dose dependently suppressed the cAMP level and inhibited ecdysteroidogenesis in the larval prothoracic glands at much lower concentrations than the prothoracicostatic peptide, the other prothoracicostatic factor reported previously. In vitro analyses using a prothoracic gland incubation method revealed that Bommo-myosuppressin and prothoracicostatic peptide regulate the prothoracic gland activity via different receptors. In situ hybridization and immunohistochemistry revealed the existence of Bommo-myosuppressin in the brain neurosecretory cells projecting to neurohemal organs in which it is stored. We also identified and functionally characterized a specific receptor for Bommo-myosuppressin and showed its high expression in the prothoracic glands. All these results suggest that Bommo-myosuppressin functions as a prothoracicostatic hormone and plays an important role in controlling insect development.
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Affiliation(s)
- Naoki Yamanaka
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
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73
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Claeys I, Poels J, Simonet G, Franssens V, Van Loy T, Van Hiel MB, Breugelmans B, Vanden Broeck J. Insect Neuropeptide and Peptide Hormone Receptors: Current Knowledge and Future Directions. VITAMINS & HORMONES 2005; 73:217-82. [PMID: 16399412 DOI: 10.1016/s0083-6729(05)73007-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Peptides form a very versatile class of extracellular messenger molecules that function as chemical communication signals between the cells of an organism. Molecular diversity is created at different levels of the peptide synthesis scheme. Peptide messengers exert their biological functions via specific signal-transducing membrane receptors. The evolutionary origin of several peptide precursor and receptor gene families precedes the divergence of the important animal Phyla. In this chapter, current knowledge is reviewed with respect to the analysis of peptide receptors from insects, incorporating many recent data that result from the sequencing of different insect genomes. Therefore, detailed information is provided on six different peptide receptor families belonging to two distinct receptor categories (i.e., the heptahelical and the single transmembrane receptors). In addition, the remaining problems, the emerging concepts, and the future prospects in this area of research are discussed.
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MESH Headings
- Animals
- Drosophila/genetics
- Drosophila/physiology
- Drosophila Proteins/genetics
- Drosophila Proteins/physiology
- Forecasting
- Frizzled Receptors/genetics
- Frizzled Receptors/physiology
- Insecta/genetics
- Insecta/physiology
- Invertebrate Hormones/genetics
- Invertebrate Hormones/physiology
- Receptor Protein-Tyrosine Kinases/physiology
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/physiology
- Receptors, Guanylate Cyclase-Coupled/genetics
- Receptors, Guanylate Cyclase-Coupled/physiology
- Receptors, Invertebrate Peptide/genetics
- Receptors, Invertebrate Peptide/physiology
- Receptors, Peptide/genetics
- Receptors, Peptide/physiology
- Receptors, Tachykinin/genetics
- Receptors, Tachykinin/physiology
- Receptors, Transforming Growth Factor beta/physiology
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Affiliation(s)
- Ilse Claeys
- Laboratory for Developmental Physiology, Genomics and Proteomics Department of Animal Physiology and Neurobiology, Zoological Institute K.U.Leuven, Naamsestraat 59, B-3000 Leuven, Belgium
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74
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Gu SH, Chow YS. Analysis of ecdysteroidogenic activity of the prothoracic glands during the last larval instar of the silkworm, Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2005; 58:17-26. [PMID: 15599936 DOI: 10.1002/arch.20029] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The cellular mechanism underlying ecdysteroidogenesis throughout the last larval instar of the silkworm, Bombyx mori, was analyzed by determining the in vitro ecdysteroid secretory activity of the prothoracic glands and cAMP accumulation of gland cells, as well as changes in responsiveness to stimulation by prothoracicotropic hormone (PTTH) and 1-methyl-3-isobutylxanthine (MIX). It was found that the prothoracic glands during the first 3 days of the last instar cannot produce detectable ecdysteroid and showed no response to stimulation by PTTH or 1-methyl-3-isobutylxanthine (MIX). However, artificial elevation of cellular cAMP levels by in vitro dibutyryl cAMP treatment stimulated the glands to secrete detectable ecdysteroid, implying the presence of a cAMP-dependent ecdysteroidogenic apparatus during this stage. From days 3 to 8, basal gland activities fluctuated, but the glands showed activation responses to PTTH and to the chemicals that increase cellular cAMP levels. After the occurrence of the peak in basal gland activity on day 9, glands on day 10 showed no response to PTTH, implying a refractory state of the glands to PTTH stimulation. For cAMP accumulation, it was found that glands on day 2 began to show increased cAMP accumulation to PTTH, implying that the acquisition of gland competency for elevation of cAMP levels after stimulation by PTTH precedes that of ecdysteroid production. Moreover, during most parts of the last larval instar (between days 3 and 8) and at the pupation stage, greatly increased cAMP accumulation upon stimulation by PTTH was observed only in the presence of MIX, indicating that cAMP phosphodiesterase levels may be high during these stages. From these results, we concluded that development-specific PTTH signal transduction during the last larval instar, which shows a different pattern from that of the penultimate larval instar, may play an important role in regulating changes in prothoracic gland activity and in leading to larval-pupal metamorphosis.
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Affiliation(s)
- Shi-Hong Gu
- Department of Zoology, National Museum of Natural Science, 1 Kuan Chien Road, Taichung 404-19, Taiwan, ROC.
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75
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Wang J, Meyering-Vos M, Hoffmann KH. Multilocal expression of B-type allatostatins in crickets (Gryllus bimaculatus). ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.07.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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76
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Wang J, Meyering-Vos M, Hoffmann KH. Cloning and tissue-specific localization of cricket-type allatostatins from Gryllus bimaculatus. Mol Cell Endocrinol 2004; 227:41-51. [PMID: 15501583 DOI: 10.1016/j.mce.2004.07.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 07/08/2004] [Accepted: 07/29/2004] [Indexed: 10/26/2022]
Abstract
Cricket- or B-type allatostatins [W(X(6))W-amides] inhibit the biosynthesis of juvenile hormones in vitro in crickets. Peptides of this family are present also in other insects where they may bare different functions. Here we report the identification of a partial sequence of the B-type preproallatostatin from Gryllus bimaculatus. By PCR screening of a random primer cDNA library and by RACE, a 535bp 3'cDNA sequence was obtained which encodes a putative translation product of 85 amino acids, containing three copies of Grybi-AST B1 and one copy each of Grybi-AST B2, Grybi-AST B3, and Grybi-AST B6. The last represents a novel member of this peptide family. By means of one-step RT-PCR, RNA dot blot, and RT in situ PCR analyses the mRNA expression of the gene in the central nervous system and the digestive tract of female adult crickets was demonstrated. The results confirm that the B-type allatostatins of G. bimaculatus are brain-gut peptides.
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Affiliation(s)
- J Wang
- Department of Animal Ecology I, University of Bayreuth, 95440 Bayreuth, Germany
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77
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Liu X, Tanaka Y, Song Q, Xu B, Hua Y. Bombyx mori prothoracicostatic peptide inhibits ecdysteroidogenesis in vivo. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2004; 56:155-161. [PMID: 15274176 DOI: 10.1002/arch.20005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bombyx prothoracicostatic peptide (Bom-PTSP) is a brain neuropeptide that has recently been reported to have in vitro inhibitory activity to prothoracicotropic hormone (PTTH)-stimulated ecdysteroid biosynthesis in the prothoracic gland of the silkworm, Bombyx mori. In the present report, Bom-PTSP has been shown to significantly decrease hemolymph ecdysteroid titer in the fifth instar larvae when Bom-PTSP was injected into the fifth instar day 8 silkworm larvae, resulting in significant delay in spinning behavior. This is the first evidence that Bom-PTSP inhibits in vivo ecdysteroidogenesis in the silkworm.
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Affiliation(s)
- Xin Liu
- Institute of Nuclear-Agricultural Science, Zhejiang University, Zhejiang, China
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78
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Audsley N, Weaver RJ. A comparison of the neuropeptides from the retrocerebral complex of adult male and female Manduca sexta using MALDI-TOF mass spectrometry. ACTA ACUST UNITED AC 2003; 116:127-37. [PMID: 14599724 DOI: 10.1016/j.regpep.2003.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The occurrence of neuropeptides in the retrocerebral complexes of adult male and females of the tobacco hawkmoth, Manduca sexta, was investigated using matrix-assisted laser desorption time of flight (MALDI-TOF) mass spectrometry (MS), post source decay (PSD) and collision-induced dissociation (CID) MS/MS. From fractions of methanol extracts of corpora cardiaca (CC)/corpora allata (CA), separated by reversed-phase high performance liquid chromatography (RP-HPLC), a total of 11 mass ions were assigned to known peptides from M. sexta. These peptides were adipokinetic hormone (AKH), FLRFamides I, II and III, crustacean cardioactive peptide (CCAP), cardioactive peptide 2b (CAP(2b)), three myoinhibitory peptides, corazonin, and M. sexta allatostatin (Manse-AS). A further six masses were in agreement with Y/FXFGLamide allatostatins identified from other Lepidoptera. The sequence identities of FLRFamide I and AKH were confirmed using post source decay analysis. Fragmentation by collision-induced dissociation MS/MS identified an extended AKH peptide. The apparent differences in the peptides present in male and female retrocerebral complexes are most likely quantitative rather than sex specific.
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Affiliation(s)
- Neil Audsley
- Central Science Laboratory, Sand Hutton, York YO41 1LZ, UK.
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79
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Sun JS, Zhang TY, Zhang QR, Xu WH. Effect of the brain and suboesophageal ganglion on pupal development in Helicoverpa armigera through regulation of FXPRLamide neuropeptides. ACTA ACUST UNITED AC 2003; 116:163-71. [PMID: 14599728 DOI: 10.1016/j.regpep.2003.09.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent studies in Helicoverpa armigera report a novel role for diapause hormone (DH), pheromone biosynthesis activating neuropeptide (PBAN) and three other FXPRLamide neuropeptides secreted from suboesophageal ganglion (SG) in terminating pupal diapause. In the present paper, we investigated the role of these five FXPRLamide family neuropeptides on pupal development. Although removal of SG could not make nondiapause-destined pupae enter diapause-like status, it did make them eclose approximately 0.6-1.2 days later when compared with the controls. The results of competitive ELISAs showed a high level of FXPRLamide titer in the hemolymph of the SG-removed pupae and this may be due to the expression of the DH-PBAN gene in tissues other than SG. DH-PBAN mRNA and peptides were also detected in the thoracic ganglia (TGs) by RT-PCR and immunocytochemistry. The expression of DH-PBAN gene in the TGs of the SG-removed pupae is significantly higher than that in normal pupae by quantitative PCR and immunocytochemistry. Decerebration experiments proved that the decerebrated pupae could enter diapause-like status through down-regulation of FXPRLamide titer in hemolymph. Our studies confirm that the brain plays an important role in the determination of pupal development by regulating the synthesis and release of FXPRLamide neuropeptides in H. armigera. Thus, the function of FXPRLamide peptides in H. armigera is closely correlated with pupal development.
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Affiliation(s)
- Jiu-Song Sun
- Department of Molecular and Cell Biology, University of Science and Technology of China, Hefei, 230027, China
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80
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Sarkar NRS, Tobe SS, Orchard I. The distribution and effects of Dippu-allatostatin-like peptides in the blood-feeding bug, Rhodnius prolixus. Peptides 2003; 24:1553-62. [PMID: 14706534 DOI: 10.1016/j.peptides.2003.07.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Using a polyclonal antiserum to Dippu-allatostatin 7 (Dippu-AST 7; formerly AST 1) of the cockroach Diploptera punctata, we have demonstrated the presence of AST-like immunoreactivity (ALI) in cells and processes throughout the nervous system, gut, and peripheral tissues of unfed fifth instar and adult Rhodnius prolixus. ALI in apparent neurosecretory cells of the brain, suboesophageal ganglion, and mesothoracic ganglionic mass, as well as in midgut endocrine cells, suggests that Rhodnius allatostatins may act as neurohormones/hormones. The presence of ALI in possible interneurons and areas of neuropile throughout the CNS also suggests roles as neuromodulators and/or neurotransmitters. Dippu-AST 7 inhibits spontaneous and leucokinin 1 (LK 1)-induced contractions of the Rhodnius hindgut in a dose-dependent manner. The low concentrations capable of inhibiting both spontaneous (10(-12)M) and LK 1-induced contractions (10(-10) to 10(-9)M) suggest that ASTs may be acting as neurohormones/hormones on the hindgut. We have also shown that Dippu-AST 7 influences the muscle activity of the Rhodnius dorsal vessel at concentrations as low as 10(-11)M.
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Affiliation(s)
- Nikki R S Sarkar
- Department of Biology, University of Toronto at Mississauga, Ont., L5L 1C6, Mississauga, Canada.
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81
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Audsley N, Weaver RJ. Identification of neuropeptides from brains of larval Manduca sexta and Lacanobia oleracea using MALDI-TOF mass spectrometry and post-source decay. Peptides 2003; 24:1465-74. [PMID: 14706525 DOI: 10.1016/j.peptides.2003.07.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The occurrence of neuropeptides in the brain of larvae of the tobacco hawkmoth, Manduca sexta, and tomato moth, Lacanobia oleracea, was investigated using matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry (MS) and post-source decay (PSD). Methanolic extracts of 100 brains separated by reversed-phase high performance liquid chromatography yielded numerous ion peaks, some of which were common to both species. In M. sexta six [M+H](+) ions were in agreement with peptides previously structurally characterised from M. sexta (FLRF-amides I, II and III, M. sexta allatostatin, CAP(2b) and myoinhibitory peptide VI), whereas a further five corresponded to other known lepidopteran peptides (cydiastatins 3 and 4, helicostatins 1 and 6 and helicokinin II). Of these the identities of FLRF-amide I, cydiastatins 3 and 4 and CAP(2b) were confirmed by PSD analysis. Fourteen [M+H](+) ions corresponding to known lepidopteran peptides (FLRF-amide I, cydiastatins 2, 3 and 4, helicostatins 1, 5, 6, 7 and 9, CCAP, CAP(2b), M. sexta allatostatin and myoinhibitory peptide VI) were measured in L. oleracea brain extracts. From this insect, cydiastatins 3 and 4, helicostatin 5 and FLRF-amide I were identified by PSD. These peptides had not previously been structurally characterised from L. oleracea.
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Affiliation(s)
- Neil Audsley
- Central Science Laboratory, Sand Hutton, YO41 1LZ, York, UK.
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82
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Davis NT, Blackburn MB, Golubeva EG, Hildebrand JG. Localization of myoinhibitory peptide immunoreactivity in Manduca sexta and Bombyx mori, with indications that the peptide has a role in molting and ecdysis. J Exp Biol 2003; 206:1449-60. [PMID: 12654884 DOI: 10.1242/jeb.00234] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For normal development of Manduca sexta larvae, the ecdysteroid titer must drop following its sudden rise at the start of the molting cycle; this sudden decline in titer may be due to myoinhibitory peptide I (MIP I), which has an inhibitory effect on the release of ecdysone by the prothoracic glands of Bombyx mori in vitro. Using an antiserum to MIP, we have demonstrated secretion of an MIP-like peptide by the epiproctodeal glands of Manduca sexta, which are located on each proctodeal nerve, just anterior to the rectum. These MIP-immunoreactive glands are also present in B. mori. In fourth-instar larvae of M. sexta, the epiproctodeal glands show a distinct cycle of synthesis and sudden release of MIP that coincides with the time of the rapid decline in ecdysteroid titer. The function of the epiproctodeal glands appears to be the timely release of MIP during the molting cycle, so as to inhibit the prothoracic glands and thus to facilitate the sudden decline in ecdysteroid titer. In addition, we have found that MIP immunoreactivity is co-localized with that of crustacean cardioactive peptide (CCAP) in the 704 interneurons; these peptides appear to be co-released at the time of ecdysis. It is known that CCAP can initiate the ecdysis motor program; our results suggest that MIP may also be involved in activating ecdysis behavior.
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Affiliation(s)
- Norman T Davis
- Division of Neurobiology, University of Arizona, Box 210077, Tucson, AZ 85721-0077, USA.
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83
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Dedos SG, Birkenbeil H. Inhibition of cAMP signalling cascade-mediated Ca2+ influx by a prothoracicostatic peptide (Mas-MIP I) via dihydropyridine-sensitive Ca2+ channels in the prothoracic glands of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2003; 33:219-228. [PMID: 12535680 DOI: 10.1016/s0965-1748(02)00206-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Measurements of Ca(2+) influx in Fura-2/AM loaded prothoracic glands (PGs) of the silkworm, Bombyx mori, after application of forskolin or the cAMP analogue, 8-bromo-cAMP, showed a steady increase in [Ca(2+)](i), which was of extracellular origin and was inhibited, in both cases, by the dihydropyridine (DHP) derivative, nitrendipine. Nitrendipine also inhibited the abrupt S(-).Bay K 8644-mediated increase in [Ca(2+)](i) and its effects were mimicked by a myoinhibitory/prothoracicostatic peptide (Mas-MIP I/PTSP), which was isolated from Manduca sexta and was found to possess ecdysteroidostatic activity in Bombyx mori PGs. This peptide blocked both the forskolin and S(-).Bay K 8644-mediated increase in [Ca(2+)](i) of PG cells. It was ineffective, however, in blocking the recombinant prothoracicotropic hormone (rPTTH)-stimulated high increase in [Ca(2+)](i) of PG cells suggesting that distinct and independently regulated Ca(2+) influx mechanisms operate in the PG cells of Bombyx mori. The dependence of DHP-sensitive Ca(2+) channels on the cAMP-signalling cascade was further corroborated by the inabilitity of nitrendipine to block the thapsigargin-stimulated high increase in [Ca(2+)](i) after depletion of Ca(2+) from the intracellular stores. This, together with the inability of thapsigargin to stimulate the cAMP levels of PG cells suggest that there is a tightly regulated cross-talk mechanism between the two signalling cascades of Ca(2+) and cAMP. The combined results suggest a cAMP-mediated regulation of the opening-state of DHP-sensitive Ca(2+) channels and stimulation of [Ca(2+)](i) increases and ecdysteroid secretion by a positive feedback mechanism. Mas-MIP I/PTSP interferes with this mechanism by blocking DHP-sensitive Ca(2+) channels. This regulatory mechanism appears to be autonomously stimulating ecdysteroidogenesis by the PGs, it is regulated by Mas-MIP I/PTSPS, and it is not involved in other Ca(2+) influx mechanisms that operate within the PG cells of Bombyx mori.
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Affiliation(s)
- S G Dedos
- Saxon Academy of Sciences at Leipzig, AG Prof. Dr. H. Penzlin, Erbertstr. 1, PF 100322, 07703 Jena, Germany.
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84
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85
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Mizoguchi A, Dedos SG, Fugo H, Kataoka H. Basic pattern of fluctuation in hemolymph PTTH titers during larval-pupal and pupal-adult development of the silkworm, Bombyx mori. Gen Comp Endocrinol 2002; 127:181-9. [PMID: 12383446 DOI: 10.1016/s0016-6480(02)00043-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
General features of the changes in hemolymph PTTH titers during larval-pupal and pupal-adult development of the silkworm Bombyx mori were analyzed by comparing the patterns of the titer changes between different races and between silkworms reared under different environmental conditions. In common to all types of the silkworms tested, we observed low PTTH titers during the phagoperiod of the final instar, a small rise in PTTH titer on the day before wandering, two middle-sized peaks of the titer at the wandering and prepupal stages, high PTTH titers during early pupal-adult development, and a gradual titer increase shortly before adult eclosion. Increases in hemolymph PTTH titer were closely correlated with increases in ecdysteroid titers and with subsequent occurrences of morphological and behavioral changes characteristic of the initiation or progression of metamorphosis. The timing of the increase in hemolymph PTTH titer on the day of wandering was photoperiodically controlled, but that timing at the later stages seemed not to be influenced by the light-dark cycle.
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Affiliation(s)
- Akira Mizoguchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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86
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Gilbert LI, Rybczynski R, Warren JT. Control and biochemical nature of the ecdysteroidogenic pathway. ANNUAL REVIEW OF ENTOMOLOGY 2002; 47:883-916. [PMID: 11729094 DOI: 10.1146/annurev.ento.47.091201.145302] [Citation(s) in RCA: 336] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Molting is elicited by a critical titer of ecdysteroids that includes the principal molting hormone, 20-hydroxyecdysone (20E), and ecdysone (E), which is the precursor of 20E but also has morphogenetic roles of its own. The prothoracic glands are the predominate source of ecdysteroids, and the rate of synthesis of these polyhydroxylated sterols is critical for molting and metamorphosis. This review concerns three aspects of ecdysteroidogenesis: (a) how the brain neuropeptide prothoracicotropic hormone (PTTH) initiates a transductory cascade in cells of the prothoracic gland, which results in an increased rate of ecdysteroid biosynthesis (upregulation); (b) how the concentrations of 20E in the hemolymph feed back on the prothoracic gland to decrease rates of ecdysteroidogenesis (downregulation); and (c) how the prothoracic gland cells convert cholesterol to the precursor of E and then 20E, a series of reactions only now being understood because of the use of a combination of classical biochemistry and molecular genetics.
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Affiliation(s)
- Lawrence I Gilbert
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3280, USA.
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87
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Blackburn MB, Jaffe H, Kochansky J, Raina AK. Identification of four additional myoinhibitory peptides (MIPs) from the ventral nerve cord of Manduca sexta. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2001; 48:121-128. [PMID: 11673841 DOI: 10.1002/arch.1064] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Four new myoinhibitory peptides were isolated and identified from the ventral nerve cord of adult Manduca sexta. The new peptides are related to two previously identified myoinhibitory peptides also isolated from adult M. sexta, Mas-MIP I and Mas-MIP II. The sequences of the new peptides are APEKWAAFHGSWamide (Mas-MIP III), GWNDMSSAWamide (Mas-MIP IV), GWQDMSSAWamide (Mas-MIP V), and AWSALHGAWamide (Mas-MIP VI). Mas-MIPs III-VI were found to inhibit spontaneous peristalsis of the adult M. sexta anterior hindgut (ileum) in vitro.
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Affiliation(s)
- M B Blackburn
- Insect Biocontrol Laboratory, USDA, ARS, PSI, BARC-West, Beltsville, Maryland 20705, USA.
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88
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Lenz C, Williamson M, Hansen GN, Grimmelikhuijzen CJ. Identification of four Drosophila allatostatins as the cognate ligands for the Drosophila orphan receptor DAR-2. Biochem Biophys Res Commun 2001; 286:1117-22. [PMID: 11527415 DOI: 10.1006/bbrc.2001.5475] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The allatostatins are generally inhibitory insect neuropeptides. The Drosophila orphan receptor DAR-2 is a G-protein-coupled receptor, having 47% amino acid residue identity with another Drosophila receptor, DAR-1 (which is also called dros. GPCR, or DGR) that was previously shown to be the receptor for an intrinsic Drosophila A-type (cockroach-type) allatostatin. Here, we have permanently expressed DAR-2 in CHO cells and found that it is the cognate receptor for four Drosophila A-type allatostatins, the drostatins-A1 to -A4. Of all the drostatins, drostatin-A4 (Thr-Thr-Arg-Pro-Gln-Pro-Phe-Asn-Phe-Gly-Leu-NH(2)) is the most effective in causing a second messenger cascade (measured as bioluminescence; threshold, 10(-9) M; EC(50), 10(-8) M), whereas the others are less effective and about equally potent (EC(50), 8 x 10(-8) M). Northern blots showed that the DAR-2 gene is expressed in embryos, larvae, pupae, and adult flies. In adult flies, the receptor is more strongly expressed in the thorax/abdomen than in the head parts, suggesting that DAR-2 is a gut receptor. This is confirmed by Northern blots from 3rd instar larvae, showing that the DAR-2 gene is mainly expressed in the gut and only very weakly in the brain. The Drosophila larval gut also contains about 20-30 endocrine cells, expressing the gene for the drostatins-A1 to -A4. We suggest, therefore, that DAR-2 mediates an allatostatin (drostatin)-induced inhibition of gut motility. This is the first report on the permanent and functional expression of a Drosophila gut neurohormone receptor.
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Affiliation(s)
- C Lenz
- Department of Cell Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, Copenhagen, DK-2100, Denmark
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89
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Dedos SG, Nagata S, Ito J, Takamiya M. Action kinetics of a prothoracicostatic peptide from Bombyx mori and its possible signaling pathway. Gen Comp Endocrinol 2001; 122:98-108. [PMID: 11352558 DOI: 10.1006/gcen.2001.7623] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A prothoracicostatic peptide (PTSP), purified from the brains of Bombyx mori, was found to inhibit ecdysteroidogenesis in the prothoracic glands (PGs) of this insect. This peptide was active at inhibiting ecdysteroidogenesis in the PGs at concentrations higher than 23 nM and glands incubated in 230 nM PTSP in vitro exhibited maximum inhibition of ecdysteroid production. By incubating PGs in vitro at different incubation periods it was observed that the first statistically significant inhibitory effect occurred after 30 min incubation in the presence of PTSP. Transferral of PGs from a medium with PTSP to a medium without PTSP resulted in the resumption of ecdysteroid production. Statistically significant inhibition of ecdysteroid production by PTSP was observed only in day 6 and in day 3 PGs of the 5th instar. The extracts of day 6 glands incubated in the presence of PTSP did not contain elevated amounts of ecdysteroid relative to controls after the incubations, indicating that PTSP does not inhibit the secretion, rather the synthesis, of ecdysteroid in the PGs. The presence of PTSP completely blocked the increased ecdysteroid production via L-type Ca(2+) channel activation by S(-)*Bay K 8644. There was no inhibition of ecdysteroid production by PTSP with glands incubated in Ca(2+)-free medium. The combined results suggest that PTSP regulates ecdysteroid synthesis only during specific stages of the 5th instar through a mechanism that likely involves the blocking of Ca(2+) influx through voltage-sensitive Ca(2+) channels in the PG cells of B. mori.
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Affiliation(s)
- S G Dedos
- Department of Integrated Biosciences, the University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, 113, Japan.
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90
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Williamson M, Lenz C, Winther AM, Nässel DR, Grimmelikhuijzen CJ. Molecular cloning, genomic organization, and expression of a C-type (Manduca sexta-type) allatostatin preprohormone from Drosophila melanogaster. Biochem Biophys Res Commun 2001; 282:124-30. [PMID: 11263981 DOI: 10.1006/bbrc.2001.4565] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The insect allatostatins are a diverse group of neuropeptides that obtained their names by their inhibitory actions on the corpora allata (two endocrine glands near the insect brain), where they block the biosynthesis of juvenile hormone (a terpenoid important for development and reproduction). Chemically, the allatostatins can be subdivided into three different peptide groups: the large group of A-type (cockroach-type) allatostatins, which have the common C-terminal sequence Y/FXFGLamide; the B-type (cricket-type) allatostatins, which have the C-terminal sequence W(X(6))Wamide in common; and a single allatostatin that we now call C-type allatostatin that was first discovered in the moth Manduca sexta, and which has a nonamidated C terminus, and a structure unrelated to the A- and B-type allatostatins. We have previously cloned the preprohormones for the A- and B-type allatostatins from Drosophila melanogaster. Here we report on the cloning of a Drosophila C-type allatostatin preprohormone (DAP-C). DAP-C is 121 amino acid residues long and contains one copy of a peptide sequence that in its processed form has the sequence <EVRYRQCYFNPISCF (drostatin-C). This drostatin-C sequence is only one amino acid residue different (F --> Y in position 4) from the Manduca sexta C-type allatostatin. The DAP-C gene has three introns and four exons and is located at position 32D2-3 on the left arm of the second chromosome. Northern blots show that the gene is strongly expressed in larvae and adult flies, but less in pupae and embryos. In situ hybridizations of larvae show that the gene is expressed in various neurons of the brain and abdominal ganglia and in endocrine cells of the midgut. This is the first publication on the structure of a C-type allatostatin from insects other than moths and the first report on the presence of all three types of allatostatins in a representative of the insect order Diptera (flies).
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Affiliation(s)
- M Williamson
- Department of Cell Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, Copenhagen, DK-2100, Denmark
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91
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Williamson M, Lenz C, Winther AM, Nässel DR, Grimmelikhuijzen CJ, Winther ME. Molecular cloning, genomic organization, and expression of a B-type (cricket-type) allatostatin preprohormone from Drosophila melanogaster. Biochem Biophys Res Commun 2001; 281:544-50. [PMID: 11181081 DOI: 10.1006/bbrc.2001.4402] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The insect allatostatins obtained their names because they block the biosynthesis of juvenile hormone (a terpenoid) in the corpora allata (two endocrine organs near the insect brain). Chemically, the allatostatins can be subdivided into three different peptide groups: the A-type allatostatins, first discovered in cockroaches, which have the C-terminal sequence Y/FXFGLamide in common; the B-type allatostatins, first discovered in crickets, which all have the C-terminal sequence W(X)(6)Wamide; and the C-type allatostatins, first discovered in the moth Manduca sexta, which have an unrelated and nonamidated C terminus. We have previously reported the structure of an A-type allatostatin preprohormone from the fruitfly Drosophila melanogaster. Here we describe the molecular cloning of a B-type prepro-allatostatin from Drosophila (DAP-B). DAP-B is 211 amino acid residues long and contains one copy each of the following putative allatostatins: AWQSLQSSWamide (drostatin-B1), AWKSMNVAWamide (drostatin-B2), <EAQGWNKFRGAWamide (drostatin-B3), EPTWNNLKGMWamide (drostatin-B4), and DQWQKLHGGWamide (drostatin-B5). All five drostatins are novel peptide structures. The DAP-B gene has one intron and two exons and is located at position 74B1 on the left arm of the third chromosome. The gene is expressed in all developmental stages, but weakly in embryos and strongly in larvae. In situ hybridizations of larvae showed that neurons in the brain and abdominal ganglia and endocrine cells in the gut expressed DAP-B. This is the first published report of a B-type allatostatin preprohormone in insects, and the first paper describing the presence of B-type allatostatins in a representative of the insect order Diptera (flies).
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Affiliation(s)
- M Williamson
- Department of Cell Biology, Zoological Institute, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
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92
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Gilbert LI, Rybczynski R, Song Q, Mizoguchi A, Morreale R, Smith WA, Matubayashi H, Shionoya M, Nagata S, Kataoka H. Dynamic regulation of prothoracic gland ecdysteroidogenesis: Manduca sexta recombinant prothoracicotropic hormone and brain extracts have identical effects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2000; 30:1079-1089. [PMID: 10989295 DOI: 10.1016/s0965-1748(00)00083-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Multiple assays were conducted in order to determine if the recently available recombinant prothoracicotropic hormone (rPTTH) from Manduca sexta is identical, or similar, to the natural hormone and if results from its use in a variety of assays confirm, or are inconsistent with, previous studies over the past 20years on PTTH action using brain extract. Brain extracts and rPTTH showed similar, if not identical, effects on the cell biology of Manduca prothoracic gland cells with the following results: increased levels of cAMP (adenosine 3':5' cyclic monophosphate) synthesis; requirement for extracellular Ca(2+) in in vitro studies; ecdysteroidogenesis stimulation in vitro; stimulation of general and specific protein synthesis; immunocytochemical identification of the two lateral cells in each brain hemisphere as the source of PTTH (the prothoracicotropes); the ability of antibodies to rPTTH to inhibit ecdysteroidogenesis stimulation in vitro; and the multiple phosphorylation of the ribosomal protein S6. The data revealed that brain extract and rPTTH show equivalent effects in all of the assays, indicating that this rPTTH is the natural PTTH of Manduca and that the data generated with brain extracts over the past two decades are indeed relevant.
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Affiliation(s)
- L I Gilbert
- Department of Biology, Campus Box #3280, Coker Hall, University of North Carolina at Chapel Hill, 27599-3280, Chapel Hill, NC, USA.
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93
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Gu SH, Tsia WH, Chow YS. Temporal analysis of ecdysteroidogenic activity of the prothoracic glands during the fourth larval instar of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2000; 30:499-505. [PMID: 10802241 DOI: 10.1016/s0965-1748(00)00026-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The cellular mechanism underlying ecdysteroidogenesis during the fourth larval instar of the silkworm, Bombyx mori, was analyzed by determining the in vitro ecdysteroid biosynthetic activity of the prothoracic glands, cAMP accumulation of the gland cells, the in vitro release of prothoracicotropic hormone (PTTH), etc. According to the differential responsiveness of prothoracic glands to PTTH, dibutyryl cAMP (dbcAMP), and 1-methyl-3-isobutylxanthine (MIX), the following different stages were classified and changes in PTTH signal transduction were assumed. During the first stage (between days 0 and 1), the glands showed low basal and PTTH-stimulated activities in both cAMP accumulation and ecdysteroidogenesis, and PTTH release in vitro was maintained at low but detectable levels, implying that a low but sustained PTTH signal may be transduced to prothoracic gland cells. On day 1.5, when low basal ecdysteroid production of the prothoracic glands was being maintained, both the responsiveness of glands to the stimulation of PTTH and PTTH release in vitro dramatically increased, indicating greatly increased PTTH transduction. On day 3 (when the basal ecdysteroidogenesis became maximal) and afterwards, high PTTH release in vitro was maintained, but the gland showed no response to PTTH, implying that the refractoriness of gland cells to PTTH may occur at this stage. We assume that the development-specific changes in PTTH signal transduction during the penultimate larval instar may play a critical role in regulating changes in ecdysteroidogenesis of the prothoracic glands.
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Affiliation(s)
- S H Gu
- Department of Zoology, National Museum of Natural Science, 1 Kuan Chien Road, Taichung, Taiwan, Republic of China
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