Department of Animal Physiology and Neurobiology, Zoological Institute, K.U. Leuven, Naamsestraat 59, Leuven, Belgium.
J Insect Physiol. 2011 Sep;57(9):1240-8. doi: 10.1016/j.jinsphys.2011.05.009. Epub 2011 Jun 15.
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.
万圣节基因的功能特征分析是阐明蜕皮激素生物合成途径的重大突破。这些基因编码细胞色素 P450 酶，在双翅目果蝇和鳞翅目烟草天蛾和家蚕中催化蜕皮激素生物合成的最后步骤。这是首次报道从半变态直翅目昆虫沙漠蝗 Schistocerca gregaria 中鉴定出两个万圣节基因 spook (spo) 和 phantom (phm)。使用 q-RT-PCR 分析了它们在终幼虫期和成虫蝗虫中的时空转录谱。测量了血淋巴中的循环蜕皮激素浓度，并发现其与 spo 和 phm 的时空转录谱变化密切相关。此外，还采用 RNA 干扰 (RNAi) 方法研究了在第五幼虫期沉默这两个转录物时的敲低效应。发现 dsRNA 处理后循环蜕皮激素水平显著降低。
