Lawrence J G, Hartl D L
Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110.
Genetica. 1991;84(1):23-9. doi: 10.1007/BF00123981.
The large open reading frames of insertion sequences from Escherichia coli were examined for their spatial pattern of codon usage bias and distribution of rarely used codons. There is a bias in codon usage that is generally lower toward the terminal ends of the coding regions, which is reflected in the occurrence of an excess of nonpreferred codons in the 3' portions of the coding regions as compared with the 5' portions. In contrast, typical chromosomal genes have a lower codon usage bias toward the 5' ends of the coding regions. These results imply that the selective forces reflected in codon usage bias may differ according to position within the coding sequence. In addition, these constraints apparently differ in important ways between genes contained in insertion sequences and those in the chromosome.
对来自大肠杆菌的插入序列的大开放阅读框进行了密码子使用偏好的空间模式和稀有密码子分布的研究。密码子使用存在偏好，这种偏好通常在编码区末端较低，这反映在与5'部分相比，编码区3'部分出现过量的非偏好密码子。相反，典型的染色体基因在编码区5'端的密码子使用偏好较低。这些结果表明，密码子使用偏好所反映的选择力可能因编码序列内的位置而异。此外，这些限制在插入序列中的基因和染色体中的基因之间显然在重要方面有所不同。
