Abstract：
In birds, vitelline membrane outer layer protein 1 (VMO1) is an exogenous protein that can be absorbed by eggs as a barrier to prevent the mixing of yolk and egg white. However, researches on VMO1 are limited in birds but not other non-avian species until now. In this study, we first identified a novel Vmo1 cDNA (Lv-Vmo1) in Pacific white shrimp (Litopenaeus vannamei), the most important cultured shrimp in the world. We further analyzed its gene organization, phylogenetic relationship and protein structure. The Lv-Vmo1 transcript was specifically expressed in the hepatopancreas without sexual dimorphism. During ovarian development in female, the hepatopancreatic Lv-Vmo1 mRNA levels showed a significant increase. By in situ hybridization, Lv-Vmo1 mRNA was present in three cell types of the hepatopancreas but neither oocytes nor follicle cells of the ovary. In contrast, immunofluorescence revealed that Lv-VMO1 protein was distributed in the cytoplasms of both hepatopancreatic cells and ovarian oocytes. Western blot showed that Lv-VMO1 protein was produced in the hepatopancreas and transported to the ovary via hemolymph circulation. Identification of a species-specific egg-entry guide protein is the key to the receptor-mediated ovarian transduction of cargo, a novel gene editing approach in oviparous animals. This study lays the mechanism for exogenous transport into penaeid shrimp eggs by VMO1, as a foundation for achieving exogenous protein-mediated incorporation into oocytes.
摘要：
在鸟类中，卵黄膜外层蛋白1（VMO1）是一种外源蛋白，可以被鸡蛋吸收，作为防止蛋黄和蛋清混合的屏障。然而,到目前为止，对VMO1的研究仅限于鸟类，而不是其他非鸟类物种。在这项研究中,我们首先在太平洋白虾（凡纳滨对虾）中鉴定了一个新的Vmo1cDNA（Lv-Vmo1），世界上最重要的养殖虾。我们进一步分析了它的基因组织，系统发育关系和蛋白质结构。Lv-Vmo1转录物在肝胰腺中特异性表达，没有性二态。在女性的卵巢发育过程中，肝胰腺Lv-Vmo1mRNA水平显着升高。通过原位杂交,Lv-Vmo1mRNA存在于肝胰腺的三种细胞类型中，但卵巢的卵母细胞和卵泡细胞中均不存在。相比之下,免疫荧光显示Lv-VMO1蛋白分布在肝胰腺细胞和卵巢卵母细胞的细胞质中。Westernblot显示Lv-VMO1蛋白在肝胰腺中产生，并通过血淋巴循环转运到卵巢。鉴定一种物种特异性的卵进入指导蛋白是受体介导的卵巢货物转导的关键，一种新的卵产动物基因编辑方法。本研究通过VMO1奠定了外源转运到对虾卵中的机制，为实现外源蛋白介导的掺入卵母细胞奠定了基础。
