title: Molecular identification and expression analysis of a diapause hormone receptor in the corn earworm, Helicoverpa zea.
abstract: Diapause hormone (DH) is an insect neuropeptide that is highly effective in terminating the overwintering pupal diapause in members of the Helicoverpa/Heliothis complex of agricultural pests, thus DH and related compounds have promise as tools for pest management. To augment our development of effective DH analogs and antagonists that could be used as diapause disruptors this study focuses on the cloning and identification of the DH receptor (DHR) in the corn earworm, Helicoverpa zea. The full-length dhr cDNA contains 2153 nucleotides encoding 511 amino acids. Our results suggest there are at least two splicing variants of Hezea-DHR. Hydrophobicity analysis and sequence alignment indicate that Hezea-DHR has 7 transmembrane regions and a highly conserved C-terminal region that is also present in related receptors. Hezea-DHR has 95%, 82% and 79% identity to a partial DHR sequence from Heliothis virescens, a full-length DHR in Orgyia thyellina, and DHR-1 in Bombyx mori, but only 45-49% identity to pheromone biosynthesis activating neuropeptide receptor (PBANR). Expression of dhr mRNA remained low in whole body extracts throughout diapause and in young nondiapausing pupae, but was distinctly elevated as development ensued in pharate adults 7 days after pupation. The highest expression of dhr mRNA we noted was in the ovary. A DHR fusion protein with enhanced-green fluorescent protein was successfully expressed heterologously in X. laevis oocytes, as verified by fluorescent imaging and Western blots, but an electrophysiological assay failed to detect receptor-ligand binding activity, which suggests that an essential cofactor and/or accessory protein is required for functional activity of the DHR.
authors.affiliation: Department of Entomology, Ohio State University, Columbus, OH, USA; Department of Evolution, Ecology and Organismal Biology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Qirui
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Entomology, Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, OH 44691, USA.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Piermarini
authors.affiliation: Insect Control and Cotton Disease Research Unit, Southern Plains Agricultural Research Center, US Department of Agriculture-Agriculture Research Service, College Station, TX 77845, USA.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Nachman
authors.affiliation: Department of Entomology, Ohio State University, Columbus, OH, USA; Department of Evolution, Ecology and Organismal Biology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA. Electronic address: Denlinger.1@osu.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Denlinger
mesh_terms: D000818:Animals; D005260:Female; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009036:Moths / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014981:Xenopus / Q000378:metabolism
chemical_list: D019476:Insect Proteins; D009479:Neuropeptides; D012333:RNA, Messenger; C075027:diapause hormone
keywords: Analogs; Diapause hormone; Diapause termination; Receptor; Xenopus oocytes