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DINeR

A Database for Insect Neuropeptide Research

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Insect Neuropeptides - Neuroparsin and Ovary Ecdysteroidogenic Hormone (OEH)

Introduction

The first neuroparsin (NP) was isolated from the pars intercerebralis-corpora cardiaca complex of the locust Locusta migratoria (Girardie et al., 1987; Girardie et al., 1989). Neuroparsin B from the locust is a homodimer consisting of two cysteine-rich peptides connected by cysteine bridges. Each monomer has 78 residues (Girardie et al., 1989). It has been shown later that locusts produce several NP variants. These probably result from alternative splicing and are expressed in a tissue-, stage-, and locust phase-dependent manner (Badisco et al., 2007; Claeys et al., 2003; Janssen et al., 2001; Veenstra, 2014). NPs and related peptides have been identified in several insect species. The NP sequences appear to be more divergent in higher insect orders, such as Diptera, and are absent in D. melanogaster, and a number of related species in the melanogaster subgroup of the Drosophila genus (Veenstra, 2010). In the mosquito, Aedes aegypti, a NP-like neurohormonal factor, the ovary ecdysteroidogenic hormone (OEH), has been identified (Brown et al., 1998). OEH plays a role in stimulating ovarian ecdysteroid biosynthesis after ingestion of a protein-rich blood meal. A receptor tyrosine kinase (RTK) was shown to mediate the effects of OEH on egg formation in this mosquito (Vogel et al., 2015). The OEH receptor is distantly related to insulin receptors, but distinguished by the presence of a Venus flytrap module, found also in amino acid receptors. Close relatives of this OEH receptor can be found in several other Diptera, including Drosophila species in which a NP sequence has been described previously (Veenstra, 2010).

Location

NP and OEH have been detected by immunocytochemistry in neuroendocrine cells of the median neurosecretory group in the pars intercerebralis of the locust and mosquito, respectively (Boureme et al., 1987; Brown et al., 1998). Only two to three OEH expressing cells were found in the mosquito brain, whereas numerous NP cells were detected in the locust. These NP and OEH cells are neurosecretory cells likely to release peptides into the hemolymph.

Function

The first NP isolated was characterized in locusts as an anti-gonadotrophic factor that displayed various effects opposite to those elicited by juvenile hormone (JH), without directly affecting JH biosynthesis. A different function of NPs appears to be as a hormone binding protein. NPs display sequence similarities with the N-terminal hormone-binding module of IGF binding proteins (IGFBPs). In A. aegypti OEH stimulates ovarian ecdysteroid biosynthesis after a blood meal. Recombinant locust NP was shown capable of interacting with a purified locust insulin-like peptide (ILP) in vitro (Badisco et al., 2008). Several other arthropod proteins, referred to as neuroparsin-like peptides (NPLPs), display sequence similarity with the N-terminal IGFBP module (Badisco et al., 2007). Taken together, these IGFBP-like proteins may function in vivo by controlling availability of ILPs, similar to as IGFBP in mammals.

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Suggested Reviews

  • Badisco, L., Claeys, I., Van Loy, T., Van Hiel, M., Franssens, V., Simonet, G., and Vanden Broeck, J. (2007). Neuroparsins, a family of conserved arthropod neuropeptides. General and comparative endocrinology 153, 64-71.
    View Review
  • Nässel, D.R., and Vanden Broeck, J. (2016). Insulin/IGF signaling in Drosophila and other insects: factors that regulate production, release and post-release action of the insulin-like peptides. Cell Mol Life Sci 73, 271 290
    View Review
  • Veenstra, J.A. (2010). What the loss of the hormone neuroparsin in the melanogaster subgroup of Drosophila can tell us about its function. Insect biochemistry and molecular biology 40, 354-361.
    View Review
  • Veenstra, J.A. (2014). The contribution of the genomes of a termite and a locust to our understanding of insect neuropeptides and neurohormones. Front Physiol 5, 454.
    View Review

References

  • Badisco, L., Claeys, I., Van Hiel, M., Clynen, E., Huybrechts, J., Vandersmissen, T., Van Soest, S., Vanden Bosch, L., Simonet, G., and Vanden Broeck, J. (2008). Purification and characterization of an insulin-related peptide in the desert locust, Schistocerca gregaria: immunolocalization, cDNA cloning, transcript profiling and interaction with neuroparsin. J Mol Endocrinol 40, 137-150.
  • Badisco, L., Claeys, I., Van Loy, T., Van Hiel, M., Franssens, V., Simonet, G., and Vanden Broeck, J. (2007). Neuroparsins, a family of conserved arthropod neuropeptides. General and comparative endocrinology 153, 64-71.
  • Boureme, D., Tamarelle, M., and Girardie, j. (1987). Production and Characterization of Antibodies to Neuroparsins A and B Isolated from the Corpora Cardiaca of the Locust. Gen Comp Endocrinol 67, 169-177.
  • Brown, M.R., Graf, R., Swiderek, K.M., Fendley, D., Stracker, T.H., Champagne, D.E., and Lea, A.O. (1998). Identification of a steroidogenic neurohormone in female mosquitoes. The Journal of biological chemistry 273, 3967-3971.
  • Claeys, I., Simonet, G., Van Loy, T., De Loof, A., and Vanden Broeck, J. (2003). cDNA cloning and transcript distribution of two novel members of the neuroparsin family in the desert locust, Schistocerca gregaria. Insect Mol Biol 12, 473-481.
  • Girardie, J., Bourême, D., Couillaud, F., Tamarelle, M., and Girardie, A. (1987). Anti-juvenile effect of neuroparsin-A, A neuroprotein isolated from locust corpora cardiaca. Insect Biochem 17, 977-983.
  • Girardie, J., Girardie, A., Huet, J.C., and Pernollet, J.C. (1989). Amino acid sequence of locust neuroparsins. FEBS letters 245, 4-8.
  • Janssen, T., Claeys, I., Simonet, G., De Loof, A., Girardie, J., and Vanden Broeck, J. (2001). cDNA cloning and transcript distribution of two different neuroparsin precursors in the desert locust, Schistocerca gregaria. Insect Mol Biol 10, 183-189.
  • Veenstra, J.A. (2010). What the loss of the hormone neuroparsin in the melanogaster subgroup of Drosophila can tell us about its function. Insect biochemistry and molecular biology 40, 354-361.
  • Veenstra, J.A. (2014). The contribution of the genomes of a termite and a locust to our understanding of insect neuropeptides and neurohormones. Front Physiol 5, 454.
  • Vogel, K.J., Brown, M.R., and Strand, M.R. (2015). Ovary ecdysteroidogenic hormone requires a receptor tyrosine kinase to activate egg formation in the mosquito Aedes aegypti. Proc Natl Acad Sci U S A 112, 5057-5062.