β-呋喃果糖苷酶调控家蚕前中部丝腺糖代谢的作用机理研究

家蚕丝腺的研究主要集中在丝腺的发育、丝蛋白基因的表达及生物反应器，对于丝腺其他功能性蛋白的研究进展缓慢。BmSuc1是首个被克隆和鉴定的动物型β-呋喃果糖苷酶(β-FFase)，在家蚕幼虫的中肠组织、前中部丝腺高量表达，然而其在体内的生物学功能尚不明确。作为碳源和能源的糖类营养的及时输送和合理调配是提高丝蛋白合成效率，改善茧丝结构和性质的重要生理过程。我们的近期研究表明BmSuc1对蚕体的蔗糖水解和糖原贮存具有主导作用，在此基础之上，本项目拟利用转基因RNAi、组学关联分析及生物化学与分子生物学等技术，从蔗糖水解酶和糖基转移酶两方面揭示β-FFase在前中部丝腺组织调节糖类代谢、影响糖酵解途径及参与丝胶蛋白糖基化的作用机制，鉴定β-FFase在丝蛋白合成等耗能过程参与能量代谢的分子功能。本项目所取得的研究成果为阐明家蚕丝腺糖类代谢和能量代谢对丝蛋白合成及茧丝结构性质的影响效应提供理论依据。

Researches about the silk gland (SG) of silkworm Bombyx mori mainly focus on the development of SG, expression and protein synthesis of silk protein genes and SG bioreactor, while it is very weak about other functional proteins existing in SG by far. A novel animal β-fructofuranosidase (β-FFase)-encoding gene BmSuc1 was first cloned and identified from B. mori, which is abundantly expressed in larval midgut and anterior and middle SG. However, function of β-FFase in vivo is still not clear. As carbon and energy sources, timely transportation and reasonable deployment of sugar nutrients are important physiological process for increasing silk proteins synthesis and improving silk structure and characters. Our recent studies showed that BmSuc1 plays an essential role in the sucrose hydrolysis and glycogen storage for silkworm larvae. Based on these new findings, in this project, we plan to reveal β-FFase’s roles in anterior and middle SG as both sucrase and glycosyltransferase by transgenic RNAi, omics correlation analysis and general biochemistry and molecular biology tools. We will mainly investigate the molecular mechanism how β-FFase controls sugar metabolism, affects glycolysis pathway and takes part in the glycosylation of sericin proteins in anterior and middle SG. Additionally, molecular function of β-FFase in the processes of silk protein assembling, transporting and spinning through participating in energy metabolism will be studied there. Theoretically speaking, our achievements in this project will contribute to better understanding the effects of sugar and energy metabolism in SG on the silk protein synthesis and silk structure and property.