Pennequin P, Robins D M, Schimke R T
Eur J Biochem. 1978 Sep 15;90(1):51-8. doi: 10.1111/j.1432-1033.1978.tb12573.x.
In the oviduct of chicks withdrawn from previous treatment with estrogens, no ovalbumin synthesis can be detected, although there are a limited number of ovalbumin mRNA sequences. These sequences are predominately associated with membrane-bound ribosomes. However, the size of the polysomes is small compared to those from the laying hen, suggesting that the inability to detect ovalbumin synthesis is the result of inefficient initiation of ovalbumin synthesis. When the rate of peptide chain elongation is reduced by treatment of chicks with cycloheximide, there is an increase in the average size of polysomes and a shift of ovalbumin mRNA sequences from small to large-sized polysomes. Readministration of estrogen to withdrawn chicks results in a time-dependent shift of monosomes to polysomes and a proportional shift of ovalbumin mRNA sequences between the two fractions, indicating that estrogen stimulates the rate of initiation of all mRNA species in the oviduct to essentially the same extent. In contrast, progesterone administration results in a preferential shift of ovalbumin mRNA relative to total RNA, suggesting a preferential effect of progesterone on initiation of protein synthesis with ovalbumin mRNA.
在先前用雌激素处理过的雏鸡的输卵管中，虽然存在数量有限的卵清蛋白mRNA序列，但检测不到卵清蛋白的合成。这些序列主要与膜结合核糖体相关。然而，与产蛋母鸡的多核糖体相比，多核糖体的尺寸较小，这表明无法检测到卵清蛋白合成是卵清蛋白合成起始效率低下的结果。当用环己酰亚胺处理雏鸡以降低肽链延伸速率时，多核糖体的平均尺寸增加，并且卵清蛋白mRNA序列从小尺寸多核糖体转移到大尺寸多核糖体。对已停止处理的雏鸡重新施用雌激素会导致单体向多核糖体的时间依赖性转移以及卵清蛋白mRNA序列在这两个部分之间的比例性转移，表明雌激素在基本上相同的程度上刺激输卵管中所有mRNA种类的起始速率。相比之下，施用孕酮会导致卵清蛋白mRNA相对于总RNA的优先转移，这表明孕酮对以卵清蛋白mRNA进行蛋白质合成的起始具有优先作用。
