CODON USAGE IN REGULATORY GENES IN ESCHERICHIA-COLI DOES NOT REFLECT SELECTION FOR RARE CODONS
CODON USAGE IN REGULATORY GENES IN ESCHERICHIA-COLI DOES NOT REFLECT SELECTION FOR RARE CODONS
复制标题
DOI：
10.1093/nar/14.19.7737
复制
发表时间：
1986-10-10
影响因子：
14.9
通讯作者：
LI, WH
中科院分区：
文献类型：
--
作者：
SHARP, PM;LI, WH
经常有人提出，由稀有tRNA种类识别的密码子（即“稀有密码子”）的差异使用代表了调节基因表达的进化策略。特别是，据报道调控基因具有非常高的罕见密码子频率。从大肠杆菌中，我们收集了高表达基因、中/低表达基因和调控基因的密码子使用数据。我们已经确定了一个明确的和一般的趋势，在密码子使用的偏见，从非常高的偏见，在非常高的表达基因，并归因于选择，而在其他基因的偏差似乎是一个相当低的突变比选择的影响。与大量具有低密码子偏好的其他中/低表达基因相比，调节基因中稀有密码子的频率没有明显的增加趋势。从这一点，以及考虑的进化速率的调控基因，和翻译速率的实验数据，我们得出结论，同义密码子的使用模式的调控基因主要反映了放松自然选择。
It has often been suggested that differential usage of codons recognized by rare tRNA species, i.e. “rare codons”, represents an evolutionary strategy to modulate gene expression. In particular, regulatory genes are reported to have an extraordinarily high frequency of rare codons. FromE.coliwe have compiled codon usage data for highly expressed genes, moderately/lowly expressed genes, and regulatory genes. We have identified a clear and general trend in codon usage bias, from the very high bias seen in very highly expressed genes and attributed to selection, to a rather low bias in other genes which seems to be more influenced by mutation than by selection. There is no clear tendency for an increased frequency of rare codons in the regulatory genes, compared to a large group of other moderately/lowly expressed genes with low codon bias. From this, as well as a consideration of evolutionary rates of regulatory genes, and of experimental data on translation rates, we conclude that the pattern of synonymous codon usage in regulatory genes reflects primarily the relaxation of natural selection.