Studies on multiple hormonal regulation of insectdevelopment by endocrine perturbation

在昆虫中，类固醇激素20-羟基蜕皮激素（20-hydroxyecdysone，20 E）通过蜕皮激素受体（ecdysone receptor，EcR）启动信号级联，在调节发育转变中起重要作用。虽然20 E已被很好地表征为蜕皮激素，但其前体蜕皮激素（E）被认为是相对无活性的化合物，因为它对经典的EcR介导的反应几乎没有或没有影响。我阐明，不仅20 E，但也E是必不可少的果蝇发育时间的调节。我还探讨了一个系统，其中蜕皮激素水平降低异位表达的失活酶。利用该系统，我发现在低水平的蜕皮激素下，二龄幼虫的发育命运由蜕皮转变为化蛹，而不是蜕皮到三龄。此外，我的特点是3-氧代类固醇作为蜕皮类固醇生物合成途径的组成部分。

In insects, a steroid hormone, 20-hydroxyecdysone (20E), plays important roles in the regulation of developmental transitions by initiating signaling cascades via the ecdysone receptor (EcR). Although 20E has been well characterized as the molting hormone, its precursor ecdysone (E) has been considered to be a relatively inactive compound because it has little or no effect on classic EcR mediated responses. I elucidate that not only 20E but also E is essential for the regulation of developmental timing in Drosophila melanogaster. I also explored a system in which ecdysteroid level is reduced by ectopic expression of an inactivating enzyme. By using the system, I find that developmental fate of second instar larva is converted to pupariation instead of molting to third instar at a low level of ecdysteroid. Further, I characterized 3-oxo steroids as components of the ecdysteroid biosynthetic pathway.