title: Diapause hormone in the Helicoverpa/Heliothis complex: A review of gene expression, peptide structure and activity, analog and antagonist development, and the receptor.
abstract: This review summarizes recent studies focusing on diapause hormone (DH) in the Helicoverpa/Heliothis complex of agricultural pests. Moths in this complex overwinter in pupal diapause, a form of developmental arrest used to circumvent unfavorable seasons. DH was originally reported in the silkmoth Bombyx mori, a species that relies on DH to induce an embryonic diapause. But, in the case of Helicoverpa/Heliothis, levels of dh transcripts and DH peptides are more abundant in nondiapausing pupae than in diapausing individuals, and DH effectively terminates diapause within a specific temperature range. A structure activity relationship study indicated that the active core of DH is the C-terminal hepta-peptide, LWFGPRLa. We designed and synthesized a first generation of DH agonists and identified two agonists (PK-2Abf and PK-Etz) that were nearly 50- and 13-fold more potent than the native hormone. These studies revealed two structural characteristics of DH and its agonists that are essential for interaction with the receptor: a trans-Pro configuration to form a type I β-turn and a hydrophobic moiety involved in ligand binding. Modification of DH at the active core yielded a potent DH antagonist (DH-Jo, acetyl-GLWA[Jo]RLa) as well as an agonist (DH-2Abf-K). Three compounds (Decyl-1963, Dodecyl-1967, Heptyl-1965) were identified as agents capable of penetrating the cuticle of young pupae and thereby preventing the entry into diapause. DH receptor cDNA was cloned and an effective in vitro high throughput screen system was established for future use. This work sets the stage for further development of DH analogs and antagonists that have the potential to disrupt insect diapause as a tool for pest management.
authors.affiliation: Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Department of Evolution, Ecology, and Organismal Biology, 318 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Qirui
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Insect Control and Cotton Disease Research Unit, Southern Plains Agricultural Research Center, USDA-ARS, 2881 F&B Road, College Station, TX 77845, USA. Electronic address: Nachman@tamu.edu.
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Nachman
authors.affiliation: Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA; Department of Evolution, Ecology, and Organismal Biology, 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; D005786:Gene Expression Regulation; D007301:Insect Hormones / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009036:Moths / Q000235:genetics / Q000378:metabolism; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D007301:Insect Hormones; D019476:Insect Proteins; D009479:Neuropeptides; D011956:Receptors, Cell Surface; C075027:diapause hormone
keywords: Analogs development; Diapause hormone; Diapause prevention; Diapause termination; Gene expression; Insect diapause; Receptor; Structure activity relationship