Juvenile Hormone Regulation of the Ecdysone Cascade in Insect Metamorphosis

在昆虫中蜕皮激素引起蜕皮和变态，幼体激素（JH）允许蜕皮但阻止蜕皮激素的变态作用。正在进行的免疫细胞化学研究将完成JH如何调节烟草角虫（Manduca sexta）蛹翼在成虫发育初期的外皮激素诱导的转录因子级联反应。RNA干扰消除该通路中特定mrna的技术将用于确定该级联的关键转录因子在模式形成和角质层沉积中的作用。同样的转录因子级联将在羽翼成像盘和眼原基的蛹在蜕皮到最后的幼虫期和蛹发育开始的过程中进行免疫细胞化学分析。JH在维持这两种成年前体的幼虫状态中的作用将通过实验操作进行评估，无论是在动物还是在组织培养中。remoling是一种表皮蛋白，只出现在Manduca幼虫的最后阶段，属于Takeout蛋白家族，其中包括一些JH结合蛋白。重组Moling将由杆状病毒系统产生，然后用于测试其是否与JH结合，如果是，将对其结合进行表征。此外，免疫细胞化学将研究其在表皮中相对于蛹投入时间的消失模式和广泛表达的出现。研究人员将分析JH调控的果蝇Moling同源物在幼虫表皮发育和变态中的存在及其可能的作用。USP作为一种可能的JH受体在果蝇中的作用正在与Grace Jones博士合作研究。JH预防腹部变态的生物测定将在携带突变型USP的动物身上进行，假设这些突变型USP很少或没有JH结合活性。

In insects ecdysone causes molting and metamorphosis and juvenile hormone (JH) allows molting but prevents the metamorphic action of ecdysone. Ongoing immunocytochemical studies of how JH modulates the ecdysone-induced cascade of transcription factors in the tobacco hornworm, Manduca sexta, pupal wing at the outset of adult development will be completed. The technique of RNA interference to eliminate specific mRNAs in this pathway will be used to determine the roles of key transcription factors of this cascade in pattern formation and cuticle deposition. This same transcription factor cascade will be analyzed immunocytochemically during pupal commitment of the wing imaginal disc and of the eye primordium during the molt to the final larval stage and at the initiation of pupal development. The role of JH in the maintenance of the larval state of these two adult precursors will be assessed by experimental manipulations, both in the animal and in tissue cultureMoling, an epidermal protein that appears only in the last larval stage of Manduca, belongs to the Takeout family of proteins that includes some JH-binding proteins. Recombinant Moling will be produced by a baculovirus system, then used to test whether it binds JH and, if so, the binding will be characterized. Also, the pattern of its disappearance in the epidermis relative to the time of pupal commitment and the appearance of Broad expression will be studied immunocytochemically. Putative homologs of Moling in Drosophila that are regulated by JH will be analyzed for their presence and possible role in larval epidermal development and metamorphosis. The role of USP as a possible JH receptor in Drosophila is being studied in collaboration with Dr. Grace Jones. Bioassays of JH in the prevention of abdominal metamorphosis will be done with animals bearing mutated forms of USP hypothesized to have little or no JH binding activity.