中文摘要：

转录终止子作为一种位于终止密码子后的调控信号,负责终止DNA的转录和RNA的释放。文中首次改造并分析了来源于噬菌体的λt_o终止子的发卡结构与富含尿嘧啶的序列对枯草芽孢杆菌168中基因转录终止效率以及mRNA稳定性的影响。结果表明,相对于野生型的λt_0终止子,突变体M3、M11和M12表现出了更高的转录终止效率,突变体M3、M4和M11更有利于上游绿色荧光蛋白mRNA的稳定。另外,我们发现插入RNase作用位点同样提高了mRNA的稳定性。研究结果表明终止子中的发卡环对转录终止不是必需的,同时,结果也证明了转录终止子可以作为一种潜在的工具用于提高枯草芽孢杆菌中mRNA的稳定性以及相应酶的表达。

英文摘要：

Terminators as regulatory signals are typically placed behind the last coding sequence to block the transcription of DNA to RNA and release the transcript. In the present study, the hairpin and the U-rich sequence of the bacteriophage λto terminator were first modified to investigate their effects on termination efficiency and mRNA stability in Bacillus subtilis 168. Compared with the native Xto terminator, the terminator variants M3, M11 and M12 showed higher termination efficiency values. Moreover, the variantsM3, M4 and M11 showed significant positive effects on the mRNA stability of the upstream gfp gene. Additionally, insertion of RNase site also increased the mRNA stability. The results of this study suggested that the composition of the hairpin loop is not required for effective intrinsic termination in B. subtilis. Our results also showed that the terminator could also be used as a potential tool for increasing mRNA stability and the corresponding enzyme production in B. subtilis.