Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Mol Reprod Dev. 2012 Jul;79(7):478-87. doi: 10.1002/mrd.22055.
In oviparous organisms, oocyte maturation depends on massive production of the egg yolk-precursor protein, vitellogenin (Vg). Vg is taken up by the developing oocytes through receptor-mediated endocytosis (RME), a process essential to successful reproduction. The aims of this study were to identify and characterize the yet-unknown vitellogenin receptor (VgR) from the pleocyamate crustacean Macrobrachium rosenbergii, and to investigate its expression levels during vitellogenesis and its interaction with Vg. The VgR gene was cloned, and its translated protein was specifically located at the oocyte membrane. Moreover, for the first time, a VgR protein was identified and sequenced by mass spectrometry. The putative MrVgR displayed high sequence similarity to VgRs from crustaceans, insects, and vertebrates, and its structure includes typical elements, such as an extracellular, lipoprotein-binding domain (LBD), EGF-like, and O-glycosylation domains, a transmembrane domain, and a short, C-terminal, cytosolic tail. In this article, we identify the first crustacean VgR protein, and present data demonstrating its high affinity for a Vg column followed by elution with suramin and EDTA. Additionally we demonstrate that VgR expression in the oocyte is elevated during vitellogenesis. Our results contribute to the fundamental understanding of oocyte maturation in crustaceans, and particularly elucidate Vg uptake through RME via the VgR.
在卵生生物中，卵母细胞成熟依赖于卵黄前体蛋白——卵黄蛋白原（Vg）的大量产生。Vg 通过受体介导的内吞作用（RME）被正在发育的卵母细胞吸收，这是成功繁殖所必需的过程。本研究的目的是鉴定和表征软甲纲十足目甲壳动物罗氏沼虾（Macrobrachium rosenbergii）中尚未知晓的卵黄蛋白原受体（VgR），并研究其在卵黄发生过程中的表达水平及其与 Vg 的相互作用。克隆了 VgR 基因，其翻译蛋白特异性定位于卵母细胞膜上。此外，首次通过质谱法鉴定和测序了 VgR 蛋白。推测的 MrVgR 与甲壳动物、昆虫和脊椎动物的 VgR 具有高度的序列相似性，其结构包括典型的元件，如细胞外、脂蛋白结合域（LBD）、EGF 样和 O-糖基化域、跨膜域和短的、C 末端、胞质尾部。在本文中，我们鉴定了第一个甲壳动物 VgR 蛋白，并提供了数据证明其对 Vg 柱具有高亲和力，随后用苏拉明和 EDTA 洗脱。此外，我们证明了 VgR 在卵母细胞中的表达在卵黄发生过程中升高。我们的结果有助于深入了解甲壳动物的卵母细胞成熟，特别是阐明了通过 VgR 进行的 RME 介导的 Vg 摄取。
