家蚕丝腺是组织特化的、已知蛋白质分泌能力最强大的昆虫器官，是人类驯化和选择家蚕的主要对象。改良丝腺合成的蛋白质纤维成分和有效利用丝腺的高效蛋白质分泌能力生产外源蛋白，是养蚕业和昆虫生物工程领域世界瞩目的重大课题。 我们在前期工作发现：（1）停止丝蛋白合成的幼虫蛹化过程中的退化丝腺细胞，发生了高效合成30K非丝成分的储存蛋白质；（2）后部丝腺（PSG）表达中部丝腺（MSG）特异的SER3转基因家蚕，其丝素蛋白质出现了非常有趣的分子聚合变化。 本项目以建立的20E等诱导的、转Hpgs基因诱发的不同丝腺退化发育模型，探讨退化丝腺细胞中30K c19等非丝储存蛋白质的上调表达分泌调控机制；进一步以转基因蚕为材料，探讨PSG表达组织部位异源的SER3丝胶蛋白分泌调控机制。以期阐明丝腺细胞中高效的丝蛋白质合成功能转化为合成其它蛋白质的调控机制，为开发新型蚕丝蛋白和丝腺高效表达外源蛋白的家蚕积累基础。

Bombyx mori is a domesticated economic insect. The silk gland is the major reason why people domesticate, which is known as a specialized tissue with the strongest protein secreting capacity among insects. Improving protein fiber composition synthesized by silk gland and taking use of silk gland to produce exogenous protein efficiently are the major issue in sericulture and insect bio-engineering field. According to the preliminary work, we have found that: (1) Degenerated cells in silk gland which stop producing silk protein at the pupation stage, efficiently produce 30K protein. (2) With transgenic technology, we can make Posterior silk gland (PSG) express middle silk gland (MSG) specific protein SER3, and interesting changes of the molecular aggregation are found in the silk fibroin. The research is going to investigate the regulatory mechanism that up-regulate expressed protein in degenerated silk gland, such as 30Kc19 and other non-silk proteins, based on building various degeneration developmental models of silk gland which can be induced by hormone, drug and transgenic Hpgs gene. Further investigation is going to discuss the secretion regulation mechanism of heterogenous sericin protein SER3 in PSG based on transgenic silkworm. Eventually we aim to clarify the regulatory mechanism which makes silk gland efficiently express other protein, and lay a foundation to exploite new type of silk protein and cultivate high-efficiency expression strains for exogenous protein in silkworm.