卵黄蛋白原RNA干扰可阻止幼年蝗虫的卵巢生长，并转移生殖蛋白和脂质。
Vitellogenin RNAi halts ovarian growth and diverts reproductive proteins and lipids in young grasshoppers.
作者信息
Tokar Derek R, Veleta Katherine A, Canzano Joseph, Hahn Daniel A, Hatle John D
机构信息
*Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA.
*Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA *Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, USA; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Entomology and Nematology, University of Florida, PO Box 110620, Bldg. 970 Natural Area Drive, Gainesville, FL 32611, USA.
出版信息
Integr Comp Biol. 2014 Nov;54(5):931-41. doi: 10.1093/icb/icu068. Epub 2014 Jun 11.
Reduced reproduction extends lifespan of females in many animals. To test the effects of reproduction on storage of macronutrients, we block reproductive output in the lubber grasshopper by injecting RNAi against the precursor to egg-yolk protein, vitellogenin, in early adulthood. Controls were injected with either buffer or RNAi against the major storage protein in the hemolymph, hexamerin-90. Vitellogenin RNAi greatly reduced both levels of mRNA for vitellogenin and ovarian growth, in comparison to both controls. Fat body mass was increased upon vitellogenin RNAi, but concentrations of the three hexameric storage proteins from the hemolymph were not. Surprisingly, hemolymph vitellogenin levels were increased upon vitellogenin RNAi. Total reproductive protein (hemolymph vitellogenin plus ovarian vitellin) was unchanged by vitellogenin RNAi, as reproductive protein was diverted to the hemolymph. Similarly, the increased lipid storage upon vitellogenin RNAi was largely attributable to the reduction in lipid in the ovary, due to decreased ovarian growth. A BLAST search revealed that the 515 bp sequence of vitellogenin used for RNAi had three 11 bp regions identical to the vitellogenin receptor of the cockroach Leucophaea maderae. This suggests that our treatment, in addition to reducing levels of vitellogenin transcript, may have also blocked transport of vitellogenin from the hemolymph to the ovary. This would be consistent with halted ovarian growth simultaneous with high levels of vitellogenin in the hemolymph. Nonetheless, the accumulation of vitellogenin, instead of hexameric storage proteins, is inconsistent with a simple model of the trade-off between reproduction and storage. This was observed in young females; future studies will address whether investment of proteins may shift to the soma as individuals age. Overall, our results suggest that blockage of reproduction in young grasshoppers redirects lipids to storage and reproductive proteins to the hemolymph.
繁殖能力降低可延长许多动物雌性个体的寿命。为了测试繁殖对大量营养素储存的影响，我们在成年早期通过注射针对卵黄蛋白原（一种卵黄蛋白前体）的RNA干扰来阻断美洲大螽斯的繁殖输出。对照组分别注射缓冲液或针对血淋巴中主要储存蛋白六聚蛋白-90的RNA干扰。与两个对照组相比，卵黄蛋白原RNA干扰极大地降低了卵黄蛋白原的mRNA水平和卵巢生长。卵黄蛋白原RNA干扰后脂肪体质量增加，但血淋巴中三种六聚体储存蛋白的浓度没有增加。令人惊讶的是，卵黄蛋白原RNA干扰后血淋巴中卵黄蛋白原水平升高。卵黄蛋白原RNA干扰并未改变总生殖蛋白（血淋巴卵黄蛋白原加卵巢卵黄磷蛋白），因为生殖蛋白被转移到了血淋巴中。同样，卵黄蛋白原RNA干扰后脂质储存增加主要归因于卵巢生长减少导致卵巢中脂质减少。一项BLAST搜索显示，用于RNA干扰的515 bp卵黄蛋白原序列有三个11 bp区域与蟑螂马德拉蜚蠊的卵黄蛋白原受体相同。这表明我们的处理除了降低卵黄蛋白原转录水平外，还可能阻断了卵黄蛋白原从血淋巴到卵巢的转运。这与卵巢生长停止同时血淋巴中卵黄蛋白原水平升高是一致的。尽管如此，卵黄蛋白原而非六聚体储存蛋白的积累与繁殖和储存之间权衡的简单模型不一致。这在年轻雌性个体中观察到；未来的研究将探讨随着个体年龄增长，蛋白质投资是否可能转向躯体。总体而言，我们的结果表明，阻断年轻蚱蜢的繁殖会将脂质重新导向储存，将生殖蛋白重新导向血淋巴。
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