Abstract：
The vitellogenin receptor (VgR) is essential for the uptake and transport of the yolk precursor, vitellogenin (Vg). Vg is synthesized in the fat body, released in the hemolymph, and absorbed in the ovaries, via receptor-mediated endocytosis. Besides its important role in the reproductive pathway, Vg occurs in nonreproductive worker honey bee, suggesting its participation in other pathways. The objective was to verify if the VgR occurs in the hypopharyngeal glands of Apis mellifera workers and how Vg is internalized by these cells. VgR occurrence in the hypopharyngeal glands was evaluated by qPCR analyses of VgR and immunohistochemistry in workers with different tasks. The VgR gene is expressed in the hypopharyngeal glands of workers with higher transcript levels in nurse honey bees. VgR is more expressed in 11-day-old workers from queenright colonies, compared to orphan ones. Nurse workers with developed hypopharyngeal glands present higher VgR transcripts than those with poorly developed glands. The immunohistochemistry results showed the co-localization of Vg, VgR and clathrin (protein that plays a major role in the formation of coated vesicles in endocytosis) in the hypopharyngeal glands, suggesting receptor-mediated endocytosis. The results demonstrate that VgR performs the transport of Vg to the hypopharyngeal glands, supporting the Ovary Ground Plan Hypothesis and contributing to the understanding of the role of this gland in the social context of honey bees.
摘要：
卵黄蛋白原受体（VgR）对于卵黄前体的摄取和转运至关重要，卵黄蛋白原(Vg)。Vg在脂肪体内合成，释放在血淋巴中，被卵巢吸收，通过受体介导的内吞作用。除了它在生殖途径中的重要作用，Vg发生在非生殖工人蜜蜂中，建议它参与其他途径。目的是验证VgR是否发生在Apismellifera工人的下咽腺中，以及Vg如何被这些细胞内化。通过对不同任务的工人进行VgR的qPCR分析和免疫组织化学来评估下咽腺中VgR的发生。VgR基因在护士蜜蜂中转录水平较高的工人的下咽腺中表达。VgR在来自皇后区的11天大工人中表达得更多，与孤儿相比。下咽腺发育的护士比腺体发育不良的护士表现出更高的VgR转录本。免疫组化结果显示Vg共定位,VgR和下咽腺中的网格蛋白（在内吞作用中在包被囊泡的形成中起主要作用的蛋白质），提示受体介导的内吞作用。结果表明，VgR执行Vg到下咽腺的运输，支持卵巢地面计划假说，并有助于理解该腺体在蜜蜂社会环境中的作用。
