Sokolova E E, Vlasov P K, Egorova T V, Shuvalov A V, Alkalaeva E Z
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.
Institute of Science and Technology, Klosterneuburg, 3400 Austria.
Mol Biol (Mosk). 2020 Sep-Oct;54(5):837-848. doi: 10.31857/S0026898420050080.
Translation termination is a finishing step of protein biosynthesis. The significant role in this process belongs not only to protein factors of translation termination but also to the nearest nucleotide environment of stop codons. There are numerous descriptions of stop codons readthrough, which is due to specific nucleotide sequences behind them. However, represented data are segmental and don't explain the mechanism of the nucleotide context influence on translation termination. It is well known that stop codon UAA usage is preferential for A/T-rich genes, and UAG, UGA-for G/C-rich genes, which is related to an expression level of these genes. We investigated the connection between a frequency of nucleotides occurrence in 3' area of stop codons in the human genome and their influence on translation termination efficiency. We found that 3' context motif, which is cognate to the sequence of a stop codon, stimulates translation termination. At the same time, the nucleotide composition of 3' sequence that differs from stop codon, decreases translation termination efficiency.
翻译终止是蛋白质生物合成的最后一步。这一过程中的重要作用不仅属于翻译终止的蛋白质因子，还属于终止密码子最邻近的核苷酸环境。关于终止密码子通读有大量描述，这是由于其后面的特定核苷酸序列所致。然而，所呈现的数据是片段性的，并未解释核苷酸上下文对翻译终止的影响机制。众所周知，终止密码子UAA在富含A/T的基因中使用更为优先，而UAG、UGA在富含G/C的基因中使用更为优先，这与这些基因的表达水平相关。我们研究了人类基因组中终止密码子3'区域核苷酸出现频率与其对翻译终止效率的影响之间的联系。我们发现，与终止密码子序列同源的3'上下文基序会刺激翻译终止。与此同时，与终止密码子不同的3'序列的核苷酸组成会降低翻译终止效率。
