Thompson D B, Treat-Clemons L G, Doane W W
Department of Zoology, Arizona State University, Tempe 85287-1501.
J Exp Zool. 1992 May 1;262(2):122-34. doi: 10.1002/jez.1402620203.
The regulatory effects of allelic substitution at the trans-acting mapP locus and of dietary glucose on the expression of the duplicate genes for alpha-amylase (Amy) in Drosophila melanogaster were examined in the anterior midgut and posterior midgut regions of mature flies. The levels of amylase activity and amylase protein, as well as the abundance of amylase-specific RNA, were quantified. All 3 parameters of Amy expression were concordant. Results indicate that the effects of both mapP and dietary glucose are exerted at the level of amylase RNA. However, the tissue-specific effects of mapP are restricted to the posterior midgut and can therefore be distinguished from the effects of glucose in food medium, which influences amylase RNA levels in both the anterior and posterior midgut regions. Our data suggest that, in large part, strain-specific effects of dietary glucose can be explained on the basis of alternate alleles at the mapP locus in different homozygous strains of flies. Levels of amylase RNA in tissue extracts of flies from an amylase-null strain were also measured. Low levels were observed in both anterior and posterior midgut extracts. These were unresponsive to dietary conditions.
在成熟果蝇的中肠前部和中肠后部区域，研究了反式作用mapP位点的等位基因替换以及膳食葡萄糖对黑腹果蝇α-淀粉酶（Amy）重复基因表达的调控作用。对淀粉酶活性、淀粉酶蛋白水平以及淀粉酶特异性RNA丰度进行了定量分析。Amy表达的所有这三个参数都是一致的。结果表明，mapP和膳食葡萄糖的作用均在淀粉酶RNA水平发挥。然而，mapP的组织特异性作用仅限于中肠后部，因此可以与食物培养基中葡萄糖的作用区分开来，后者会影响中肠前部和中肠后部区域的淀粉酶RNA水平。我们的数据表明，在很大程度上，膳食葡萄糖的品系特异性作用可以基于不同纯合果蝇品系中mapP位点的替代等位基因来解释。还测量了来自淀粉酶缺失品系果蝇组织提取物中的淀粉酶RNA水平。在前部和后部中肠提取物中均观察到低水平。这些对膳食条件无反应。
