Carlson B A, Kwon S Y, Lee B J, Hatfield D
Section on the Molecular Biology of Selenium, Laboratory of Basic Research and Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA.
Mol Cells. 2000 Feb 29;10(1):113-8. doi: 10.1007/s10059-000-0113-6.
In this study, we compare the efficiency of Asn tRNA from mammalian sources with and without the highly modified queuosine (Q) base in the wobble position of its anticodon and Asn tRNA from yeast, which naturally lacks Q base, to promote frameshifting. Interestingly, no differences in the ability of the two mammalian Asn tRNAs to promote frameshifting were observed, while yeast tRNA(ASn)(-Q) promoted frameshifting more efficiently than its mammalian counterparts in both rabbit reticulocyte lysates and wheat germ extracts. The shiftability of yeast Asn tRNA is therefore not due, or at least not completely, to the lack of Q base and most likely the shiftiness resides in structural differences elsewhere in the molecule. However, we cannot absolutely rule out a role of Q base in frameshifting as wheat germ extracts and a lysate depleted of most of its tRNA and supplemented with calf liver tRNA contain both Asn tRNA with or without Q base.
在本研究中，我们比较了来自哺乳动物的天冬酰胺tRNA（其反密码子摆动位置带有和不带有高度修饰的queuosine（Q）碱基）以及来自酵母的天冬酰胺tRNA（天然缺乏Q碱基）促进移码的效率。有趣的是，未观察到两种哺乳动物天冬酰胺tRNA促进移码能力的差异，而酵母tRNA(ASn)(-Q)在兔网织红细胞裂解物和小麦胚芽提取物中比其哺乳动物对应物更有效地促进移码。因此，酵母天冬酰胺tRNA的移码能力并非，或至少不完全是由于缺乏Q碱基，并且移码性很可能存在于分子其他部位的结构差异中。然而，我们不能完全排除Q碱基在移码中的作用，因为小麦胚芽提取物以及去除了大部分tRNA并补充了小牛肝tRNA的裂解物中同时含有带有或不带有Q碱基的天冬酰胺tRNA。
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