蜕皮激素对昆虫胚胎发育至关重要。已有的研究表明，调控昆虫胚胎发育的蜕皮激素是母体起源的，但其起源的分子机制仍不清楚。我们从家蚕卵转录组中鉴定了一个母源基因shadow-like，该基因的直系同源子在烟草天蛾幼虫中已被证实参与了蜕皮激素的合成。据此，我们推测这个母源基因可能参与了合成家蚕早期胚胎发育所需的蜕皮激素。这一线索是申请人及课题组在家蚕蜕皮激素代谢调控机制方面多年研究积累的结果。本项目将首先检测家蚕shadow-like基因编码蛋白的酶活性，分析该基因在家蚕卵子发生和胚胎发育进程中的表达变化模式，研究其影响早期胚胎发育过程中蜕皮激素滴度变化的机制；阐明蜕皮激素在受精卵中做为信号因子调控家蚕早期胚胎发育进程的机理。研究结果将拓展对昆虫胚胎发育期蜕皮激素合成和调控机制的认知，有原创性，同时，也可能为人工调控家蚕胚胎发育及鳞翅目害虫防治提供新思路。

Ecdysteroids are of primary importance for embryonic development of insects. Previous studies indicated that ecdysteroids regulating embryonic development of insects are maternally originated. However, the molecular mechanisms of maternal origin of ecdysteroids are still unknown. By analyzing transciptome of the silkworm eggs, we have identified a maternal gene shadow-like, whose ortholog in the tobacco hornworm (Manduca sexta) was verified to encode an enzyme synthesizing ecdysone. Thus, we speculate that a maternal gene may synthesize ecdysone required for early embryonic development of silkworm. This speculation is based on our knowledge and experience because we have continually investigated the metabolic mechanisms of ecdysteroids in silkworm for many years. This project is first to identify the property of an enzyme encoded by a shadow-like gene in silkworm and to investigate an expression pattern of the gene as well as a change mode of the corresponding mRNA level during oogenesis and embryonic development. Then, how the shadow-like gene affects ecdysone titer during early embryonic development will be investigated. The second goal of this project is to clarify the mechanism that ecdysone regulates early embryonic development of silkworm as a signaling factor. The results will not only expand our knowledge about synthesis and regulatory mechanism of ecdysone during embryonic development of insects but also provide new clues for artificially regulating embryonic development of silkworm and for controlling Lepidopteran pests.