Rothstein S J, Reznikoff W S
Cell. 1981 Jan;23(1):191-9. doi: 10.1016/0092-8674(81)90284-1.
The inverted repeats of Tn5 are functionally different. One repeat codes for larger polypeptides, which are required for transposition. The other repeat has a better promoter for the neomycin resistance gene in the region of the repeat near the unique sequences. These dissimilarities are now shown to be caused by a single base pair difference. This change both creates a better promoter sequence and codes for part of a new UAA nonsense codon. Mutants in which the DNA sequence of a repeat is altered only at this base pair are shown to function like the opposite repeat. Furthermore, it is possible to suppress the UAA nonsense codon with an ochre suppressor, making the previously abbreviated polypeptides functional in transposition.
Tn5的反向重复序列在功能上有所不同。一个重复序列编码较大的多肽，这些多肽是转座所必需的。另一个重复序列在靠近独特序列的重复区域内，具有更好的新霉素抗性基因启动子。现在表明，这些差异是由一个单碱基对差异引起的。这种变化既产生了更好的启动子序列，又编码了一个新的UAA无义密码子的一部分。仅在这个碱基对处改变重复序列DNA序列的突变体，其功能类似于相反的重复序列。此外，用赭石抑制子可以抑制UAA无义密码子，使先前缩短的多肽在转座中发挥功能。
