Baim S B, Sherman F
Department of Biophysics, University of Rochester School of Medicine and Dentistry, New York 14642.
Mol Cell Biol. 1988 Apr;8(4):1591-601. doi: 10.1128/mcb.8.4.1591-1601.1988.
The mRNA sequence and structures that modify and are required for translation of iso-1-cytochrome c in the yeast Saccharomyces cerevisiae were investigated with sets of CYC1 alleles having alterations in the 5' leader region. Measurements of levels of CYC1 mRNA and iso-1-cytochrome c in strains having single copies of altered alleles with nested deletions led to the conclusion that there is no specific sequence adjacent to the AUG initiator codon required for efficient translation. However, the nucleotides preceding the AUG initiator codon at positions -1 and -3 slightly modified the efficiency of translation to an order of preference similar to that found in higher cells. In contrast to large effects observed in higher eucaryotes, the magnitude of this AUG context effect in S. cerevisiae was only two- to threefold. Furthermore, introduction of hairpin structures in the vicinity of the AUG initiator codon inhibited translation, with the degree of inhibition related to the stability and proximity of the hairpin. These results with S. cerevisiae and published findings on other organisms suggest that translation in S. cerevisiae is more sensitive to secondary structures than is translation in higher eucaryotes.
利用在5'前导区有改变的CYC1等位基因集，研究了酿酒酵母中修饰异-1-细胞色素c翻译并为其翻译所必需的mRNA序列和结构。对具有嵌套缺失的单拷贝改变等位基因的菌株中CYC1 mRNA和异-1-细胞色素c水平的测量得出结论，高效翻译所需的紧邻AUG起始密码子的特定序列不存在。然而，位于AUG起始密码子前-1和-3位置的核苷酸对翻译效率有轻微修饰，其偏好顺序与在高等细胞中发现的相似。与在高等真核生物中观察到的大效应相反，酿酒酵母中这种AUG上下文效应的幅度仅为两到三倍。此外，在AUG起始密码子附近引入发夹结构会抑制翻译，抑制程度与发夹的稳定性和接近度有关。酿酒酵母的这些结果以及关于其他生物体的已发表研究结果表明，酿酒酵母中的翻译比高等真核生物中的翻译对二级结构更敏感。
