Søndergaard L, Mauchline D, Egetoft P, White N, Wulff P, Bownes M
Department of Genetics, University of Copenhagen, Denmark.
Mol Gen Genet. 1995 Jul 22;248(1):25-32. doi: 10.1007/BF02456610.
The yolk protein genes (yps) of Drosophila melanogaster are only expressed in the ovary and fat body of female flies if they are supplied with proteinaceous food. This nutritional response is specific to the yp genes. We have used transgenic flies transformed with a series of constructs bearing deletions in the upstream region of the yp1 and yp2 genes attached to a reporter gene to search for DNA sequences responsible for the nutritional induction specific for yp1 and yp2 genes. Several regions were shown independently of each other to confer nutritional regulation on the expression of the yp1 and yp2 genes. This regulation can be induced both on the yp promoter and the heterologous Drosophila heat-shock 70 (hsp 70) promoter. The redundancy of sequences conferring a nutritional response on the yp genes is similar to that observed for the female specificity of these genes and suggest that several DNA binding proteins interact to provide the correct regulation of these genes. These results suggest that nutrition acts to modify the level of a trans-acting factor in the fat body. Northern blot analysis showed that the transcript levels from the dsx gene are not affected by nutrition, indicating that the response is not mediated via the dsx gene.
黑腹果蝇的卵黄蛋白基因（yps）只有在雌性果蝇摄入含蛋白质食物时才会在其卵巢和脂肪体中表达。这种营养反应对卵黄蛋白基因具有特异性。我们利用转基因果蝇进行研究，这些果蝇被一系列构建体所转化，这些构建体在与报告基因相连的yp1和yp2基因上游区域带有缺失，以此来寻找负责yp1和yp2基因特异性营养诱导的DNA序列。几个区域彼此独立地显示出能赋予yp1和yp2基因表达营养调控。这种调控既能在yp启动子上诱导，也能在异源果蝇热休克70（hsp 70）启动子上诱导。赋予卵黄蛋白基因营养反应的序列冗余性与这些基因的雌性特异性所观察到的情况相似，这表明几种DNA结合蛋白相互作用以提供对这些基因的正确调控。这些结果表明营养作用于改变脂肪体中转录因子的水平。Northern印迹分析表明dsx基因的转录水平不受营养影响，这表明该反应不是通过dsx基因介导的。
