Genetics of Nonsense Suppressor tRNAs in Escherichia coli
Genetics of Nonsense Suppressor tRNAs in Escherichia coli
复制标题
大肠杆菌中无义抑制 tRNA 的遗传学
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
Y. Shimura
中科院分区：
文献类型：
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作者：
H. Ozeki;H. Inokuchi;F. Yamao;M. Kodaira;H. Sakano;T. Ikemura;Y. Shimura
tRNA的遗传方法起源于对大肠杆菌中无义抑制子的研究，该抑制子可以特异性地恢复细菌或噬菌体中的无义突变。UAG（琥珀色）、UAA（赭色）和UGA（蛋白石色）这三个密码子不编码氨基酸，这是由于缺乏与这些密码子对应的反密码子（称为无义密码子）的trna。它们通常不存在于基因的编码区，但可以由无义突变产生，导致肽链延伸在该位点终止。因此，如果tRNA基因发生突变，改变编码特异性以识别无义密码子，则改变后的tRNA可能通过在翻译过程中插入特定氨基酸来抑制其他基因的无义突变。尽管这种抑制可能以多种方式发生（有关综述，见Gorini 1971； Steege and Soll 1979），但无意义抑制通常归因于tRNA的抑制。错义突变或移码突变也会被特定于每个突变的改变的trna所抑制（回顾，见Steege和Soll 1979）。在抑制基因突变的情况下，突变体通常表现出与普通基因不同的阳性特征（su +），并且优于其等位基因野生型基因（su−）。因此，检测携带无义抑制因子的菌株或从su -菌株中分离新的抑制突变体在遗传操作中相对容易，事实上，许多不同的无义抑制因子（如su + 1， su + 2, su + B， su + C等）在完全了解之前就已经被检测到。他们可以…
The genetic approach to tRNA originated in the study of nonsense suppressors in Escherichia coli that could specifically restore nonsense mutations in bacteria or bacteriophages. Three codons, UAG (amber), UAA (ocher), and UGA (opal), do not code for an amino acid due to the lack of tRNAs with anticodons corresponding to these codons, called nonsense codons. They are not normally present within the coding regions of genes, but can be generated by nonsense mutations, resulting in the termination of peptide chain elongation at the site. Accordingly, if a mutation occurs in a tRNA gene that alters the coding specificity to recognize a nonsense codon, the altered tRNA may suppress the nonsense mutations in other genes by inserting a specific amino acid during the process of translation. Although the suppression may take place in various ways (for reviews, see Gorini 1971; Steege and Soll 1979), nonsense suppression has been generally attributed to the tRNA suppression. Missense or frameshift mutations are also suppressed by altered tRNAs specific to each mutation (for a review, see Steege and Soll 1979). In the case of suppressor gene mutations, a mutant normally shows positive character ( su + ) differing from ordinary genes and is dominant over its allelic wild-type gene ( su − ). Accordingly, the detection of strains carrying nonsense suppressors or the isolation of new suppressor mutants from su − strains is relatively easy in genetic operation, and, in fact, many different nonsense suppressors (e.g., su + 1 , su + 2, su + B, su + C , etc.) have been detected before they were fully understood. They can...