title: Role of the Halloween genes, Spook and Phantom in ecdysteroidogenesis in the desert locust, Schistocerca gregaria.
abstract: The functional characterization of the Halloween genes represented a major breakthrough in the elucidation of the ecdysteroid biosynthetic pathway. These genes encode cytochrome P450 enzymes catalyzing the final steps of ecdysteroid biosynthesis in the dipteran Drosophila melanogaster and the Lepidoptera Manduca sexta and Bombyx mori. This is the first report on the identification of two Halloween genes, spook (spo) and phantom (phm), from a hemimetabolous orthopteran insect, the desert locust Schistocerca gregaria. Using q-RT-PCR, their spatial and temporal transcript profiles were analyzed in both final larval stage and adult locusts. The circulating ecdysteroid titers in the hemolymph were measured and found to correlate well with changes in the temporal transcript profiles of spo and phm. Moreover, an RNA interference (RNAi)-based approach was employed to study knockdown effects upon silencing of both transcripts in the fifth larval stage. Circulating ecdysteroid levels were found to be significantly reduced upon dsRNA treatment.
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute, K.U. Leuven, Naamsestraat 59, Leuven, Belgium.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Marchal
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Badisco
authors.forename: Heleen
authors.initials: H
authors.lastname: Verlinden
authors.forename: Tim
authors.initials: T
authors.lastname: Vandersmissen
authors.forename: Sofie
authors.initials: S
authors.lastname: Van Soest
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Wielendaele
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D026461:Ecdysteroids / Q000096:biosynthesis*; D005260:Female; D006110:Grasshoppers / Q000235:genetics* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D026461:Ecdysteroids; D019476:Insect Proteins; D003577:Cytochrome P-450 Enzyme System