Knöchel W, Finke C
Biochim Biophys Acta. 1978 Jul 24;519(2):365-71. doi: 10.1016/0005-2787(78)90089-8.
Cell-free synthesis of globin chains in the presence of globin mRNA in an Ehrlich ascites-cell-free system is further stimulated by addition of 18- and 28-S rRNA but not of 4-S tRNA and 5-S rRNA. This stimulation can not be observed in the wheat germ cell-free system. When 125I-labelled globin mRNA was incubated in the two systems we have found after 60 min a 75% decrease of trichloroacetic acid precipitable polynucleotides in the ascites but only a 20% decrease in the wheat germ system. The RNAase action on mRNA can be reduced by the addition of 18- and 28-S rRNA but not by 5-S rRNA and 4-S tRNA. We suggest that the stimulating effect of the two rRNA species in the ascites cell-free system is due to a higher activity of a specific RNAase in this system and a competitive protection of mRNA from RNAase action.
在艾氏腹水细胞无细胞体系中，珠蛋白链在珠蛋白mRNA存在下的无细胞合成，通过添加18 - S和28 - S rRNA可进一步受到刺激，但添加4 - S tRNA和5 - S rRNA则无此作用。在小麦胚芽无细胞体系中未观察到这种刺激作用。当将125I标记的珠蛋白mRNA在这两个体系中孵育时，我们发现在60分钟后，腹水中三氯乙酸可沉淀的多核苷酸减少了75%，而在小麦胚芽体系中仅减少了20%。添加18 - S和28 - S rRNA可降低RNA酶对mRNA的作用，但添加5 - S rRNA和4 - S tRNA则不能。我们认为，这两种rRNA在腹水无细胞体系中的刺激作用是由于该体系中一种特定RNA酶的活性较高，以及对mRNA免受RNA酶作用的竞争性保护。
