卵黄蛋白原的产生及其非营养功能的研究现状

Study on the Production of Vitellogenin and Its Non-nutritional Functions

卵黄蛋白原(Vitellogenin,Vg)是卵黄蛋白的前体,为卵生动物胚胎发育提供必需的营养物质。作为卵内重要的营养蛋白,物种之间的Vg在蛋白结构及蛋白修饰上有高度的保守性,一般包括Vit N,DUF,v WD结构域及丝氨酸修饰区等。在卵黄发育期,在激素的诱导下,雌性成年个体内的Vg在脊椎动物的肝脏或昆虫脂肪体中大量表达,经过修饰及蛋白酶剪切后,形成Vg聚合体,分泌到血淋巴中并运输至卵巢,由卵巢上的Vg受体识别,通过内吞作用入卵,并在卵内进一步加工成为成熟的卵黄蛋白。除经典的营养运输外,Vg在入卵过程中发挥多重非营养功能。Vg与病毒的结构蛋白互作,可将病毒携带入卵实现其垂直传播过程;血淋巴中的Vg通过对病原微生物的识别,介导昆虫对微生物的免疫清除;Vg在非雌性个体中的表达对虫媒病毒的水平传播及社会型昆虫的行为调节发挥功能。综述了Vg的表达、修饰、运输及其在非营养功能方向的主要研究进展,以期为后续Vg的功能研究提供指导。

Vitellogenin（Vg）is the precursor of vitellin,providing essential nutrients and energy for the developing embryo in manyoviparous animals. As an important nutrient protein in eggs,Vg＇s structure and modification are very conserved in different animals. Themature Vgs contain an N-terminal domain（Vitellogenin_N,Vit N）,a middle-region domain of unknown function（DUF）,a von Willebrandfactor type D（v WD）C-terminal domain,and a conserved polyserine tracks. During the vitellogenesis stage and under the induction ofhermones,Vg is abundantly expressed in the liver of vertebrate animals or the fat body of insects. After modification and proteolytic cleavage,the Vg subunits are assembled in tissues,secreted into the hemolymph and taken up by oocytes via receptor-mediated endocytosis. In theovaries,the Vg subunits are further processed into mature york proteins. In addition to the classic nutrient transport,Vg exerts multiple nonnutritinal function during its transport. When Vg interacts with the viral capsid protein,the virus might be transported into the insect ovary viathe uptake of Vg by developing oocytes. In hemolymph,Vg is able to play roles in immune responses,either as a pattern recognition moleculeto recognize bacteria,or as an opsonin to enhance macrophage phagocytosis. Moreover,Vg has also been reported to be expressed by nonfemales and works in behavior regulation of insects. Here,we will review the main research progresses in Vg＇s systhesis,processing,modification and its non-nutritional functions,including the functions in females and non-females. In order to provide the following Vg function.