Alkalaeva Elena, Mikhailova Tatiana
Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia.
Bioessays. 2017 Mar;39(3). doi: 10.1002/bies.201600213. Epub 2016 Dec 23.
The genetic code determines how amino acids are encoded within mRNA. It is universal among the vast majority of organisms, although several exceptions are known. Variant genetic codes are found in ciliates, mitochondria, and numerous other organisms. All revealed genetic codes (standard and variant) have at least one codon encoding a translation stop signal. However, recently two new genetic codes with a reassignment of all three stop codons were revealed in studies examining the protozoa transcriptomes. Here, we discuss this finding and the recent studies of variant genetic codes in eukaryotes. We consider the possible molecular mechanisms allowing the use of certain codons as sense and stop signals simultaneously. The results obtained by studying these amazing organisms represent a new and exciting insight into the mechanism of stop codon decoding in eukaryotes. Also see the video abstract here.
遗传密码决定了氨基酸在mRNA中的编码方式。尽管已知有一些例外情况，但它在绝大多数生物体中是通用的。在纤毛虫、线粒体和许多其他生物体中发现了变异的遗传密码。所有已揭示的遗传密码（标准密码和变异密码）都至少有一个编码翻译终止信号的密码子。然而，最近在对原生动物转录组的研究中发现了两种新的遗传密码，其中所有三个终止密码子都被重新分配了功能。在这里，我们讨论这一发现以及最近对真核生物中变异遗传密码的研究。我们考虑了允许某些密码子同时用作有义信号和终止信号的可能分子机制。通过研究这些神奇的生物体所获得的结果，为真核生物中终止密码子解码机制提供了全新且令人兴奋的见解。另请参阅此处的视频摘要。
