Wang A, Roth J R
Department of Biology, University of Utah, Salt Lake City 84112.
Genetics. 1988 Dec;120(4):875-85. doi: 10.1093/genetics/120.4.875.
The presence of transposons Tn10 or Tn5 in the genome increases the frequency with which a silent (promoter-less) gene (hisD) is mutationally activated. The activation frequency is increased 5-25-fold by Tn10 and 30-90-fold by Tn5. Activation of the hisD gene is achieved by transposition of the entire transposon or one of its flanking insertion sequences to a region just upstream of the silent gene, between a Rho-dependent termination site in the adjacent hisG gene and the hisD gene. For both Tn5 and Tn10 the component insertion sequences were found to transpose much more frequently than the entire composite element. Transposons Tn5 and Tn10 have previously been shown to carry promoters which direct transcripts into sequences adjacent to their insertion sites.
基因组中存在转座子Tn10或Tn5会增加沉默（无启动子）基因（hisD）发生突变激活的频率。Tn10使激活频率提高5至25倍，Tn5则使其提高30至90倍。hisD基因的激活是通过整个转座子或其侧翼插入序列之一转座到沉默基因上游的区域实现的，该区域位于相邻hisG基因中的一个依赖于Rho的终止位点与hisD基因之间。对于Tn5和Tn10，发现其组成性插入序列的转座频率比整个复合元件高得多。此前已表明转座子Tn5和Tn10携带启动子，这些启动子可将转录物导向与其插入位点相邻的序列。
