Weng Shih-Che, Shiao Shin-Hong
Department of Parasitology, National Taiwan University, Taipei, Taiwan.
Department of Parasitology, National Taiwan University, Taipei, Taiwan.
Insect Biochem Mol Biol. 2015 Jun;61:17-24. doi: 10.1016/j.ibmb.2015.03.010. Epub 2015 Apr 15.
The Wnt signaling pathway was first discovered as a key event in embryonic development and cell polarity in Drosophila. Recently, several reports have shown that Wnt stimulates translation and cell growth by activating the mTOR pathway in mammals. Previous studies have demonstrated that the Target of Rapamycin (TOR) pathway plays an important role in mosquito vitellogenesis. However, the interactions between these two pathways are poorly understood in the mosquito. In this study, we hypothesized that factors from the TOR and Wnt signaling pathways interacted synergistically in mosquito vitellogenesis. Our results showed that silencing Aedes aegypti Frizzled 2 (AaFz2), a transmembrane receptor of the Wnt signaling pathway, decreased the fecundity of mosquitoes. We showed that AaFz2 was highly expressed at the transcriptional and translational levels in the female mosquito 6 h after a blood meal, indicating amino acid-stimulated expression of AaFz2. Notably, the phosphorylation of S6K, a downstream target of the TOR pathway, and the expression of vitellogenin were inhibited in the absence of AaFz2. A direct link was found in this study between Wnt and TOR signaling in the regulation of mosquito reproduction.
Wnt信号通路最初是作为果蝇胚胎发育和细胞极性中的关键事件被发现的。最近，有几份报告表明，Wnt通过激活哺乳动物中的mTOR通路来刺激翻译和细胞生长。先前的研究表明，雷帕霉素靶蛋白（TOR）通路在蚊子的卵黄发生中起重要作用。然而，在蚊子中，这两条通路之间的相互作用却知之甚少。在本研究中，我们假设TOR和Wnt信号通路的因子在蚊子卵黄发生中协同相互作用。我们的结果表明，沉默埃及伊蚊卷曲蛋白2（AaFz2），一种Wnt信号通路的跨膜受体，会降低蚊子的繁殖力。我们发现，在雌蚊吸血后6小时，AaFz2在转录和翻译水平上均高表达，表明氨基酸刺激了AaFz2的表达。值得注意的是，在缺乏AaFz2的情况下，TOR通路的下游靶点S6K的磷酸化以及卵黄蛋白原的表达均受到抑制。本研究发现了Wnt和TOR信号在蚊子繁殖调控中的直接联系。
