Bai Hongkun, Qiao Hui, Li Fajun, Fu Hongtuo, Sun Shengming, Zhang Wenyi, Jin Shubo, Gong Yongsheng, Jiang Sufei, Xiong Yiwei
Wuxi Fisheries College, Nanjing Agricultural University, Wuxi 214081, PR China.
Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi 214081, PR China.
Gene. 2015 May 10;562(1):22-31. doi: 10.1016/j.gene.2014.12.008. Epub 2014 Dec 8.
Vitellogenin (Vg) is the precursor of yolk protein, which functions as a nutritive resource that is important for embryonic growth and gonad development. In this study, the cDNA encoding the Vg gene from the oriental river prawn Macrobrachium nipponense was cloned using expressed sequence tag (EST) analysis and the rapid amplification of cDNA ends (RACE) approach. The transcript encoded 2536 amino acids with an estimated molecular mass of 286.810 kDa. Quantitative real-time PCR indicated high expression of Mn-Vg in the female ovary, hemocytes, and hepatopancreas. As ovaries developed, the expression level of Mn-Vg increased in both the hepatopancreas and ovary. In the hepatopancreas, the expression level rose more slowly at the early stage of vitellogenesis and reached the peak more rapidly compared to the expression pattern in ovary. The observed changes in Mn-Vg expression level at different development stages suggest the role of nutrient source in embryonic and larval development. Eyestalk ablation caused the Mn-Vg expression level to increase significantly compared to eyestalk-intact groups during the ovary development stages. Ablation accelerated ovary maturation by removing hormone inhibition of Mn-Vg in the hepatopancreas and ovary. In adult females, Mn-Vg dsRNA injection resulted in decreased expression of Mn-Vg in both the hepatopancreas and ovary, and two injection treatment dramatically delayed ovary maturation. Vg RNA interference down-regulated the vitellogenin receptor (VgR) expression level in the ovary, which illustrates the close relationship between Vg and VgR in the process of vitellogenesis.
卵黄蛋白原（Vg）是卵黄蛋白的前体，作为一种营养资源，对胚胎发育和性腺发育至关重要。在本研究中，利用表达序列标签（EST）分析和cDNA末端快速扩增（RACE）方法，克隆了日本沼虾（Macrobrachium nipponense）中编码Vg基因的cDNA。该转录本编码2536个氨基酸，估计分子量为286.810 kDa。实时定量PCR表明，Mn-Vg在雌性卵巢、血细胞和肝胰腺中高表达。随着卵巢发育，Mn-Vg在肝胰腺和卵巢中的表达水平均升高。在肝胰腺中，卵黄发生早期表达水平上升较慢，与卵巢中的表达模式相比，更快达到峰值。在不同发育阶段观察到的Mn-Vg表达水平变化表明营养源在胚胎和幼体发育中的作用。在卵巢发育阶段，与未切除眼柄的组相比，切除眼柄导致Mn-Vg表达水平显著增加。切除眼柄通过消除对肝胰腺和卵巢中Mn-Vg的激素抑制作用，加速了卵巢成熟。在成年雌性中，注射Mn-Vg双链RNA导致肝胰腺和卵巢中Mn-Vg的表达均下降，且两次注射处理显著延迟了卵巢成熟。Vg RNA干扰下调了卵巢中卵黄蛋白原受体（VgR）的表达水平，这说明了Vg和VgR在卵黄发生过程中的密切关系。
