Zilhão Rita, Plumbridge Jacqueline, Hajnsdorf Eliane, Régnier Philippe, Arraiano Cecília M
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apt 127, 2780 Oeiras, Portugal.
Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
Microbiology (Reading). 1996 Feb;142 ( Pt 2):367-375. doi: 10.1099/13500872-142-2-367.
The rnb gene encodes ribonuclease II (RNase II), one of the two major Escherichia coli exonucleases involved in mRNA degradation. In this paper, the rnb transcript is characterized regarding its promoter and terminator regions. The combined results from S1 nuclease protection analysis, DNase I footprinting and gene fusions with lacZ have shown that rnb is expressed from two promoters. S1 nuclease protection analysis and DNA footprinting have shown that rnb has two promoters, P1 and P2. Transcriptional and translational lacZ reporter fusions, constructed to the rnb gene, revealed that P2, the rnb proximal promoter, is stronger than P1. However, P2 is not transcribed in vitro, suggesting that an additional factor is required in vivo. The 3' end of the rnb transcript mapped to a stem-loop structure immediately after the translated region.
rnb基因编码核糖核酸酶II（RNase II），它是参与大肠杆菌mRNA降解的两种主要核酸外切酶之一。在本文中，对rnb转录本的启动子和终止子区域进行了表征。S1核酸酶保护分析、DNase I足迹分析以及与lacZ的基因融合实验的综合结果表明，rnb由两个启动子表达。S1核酸酶保护分析和DNA足迹分析表明，rnb有两个启动子，P1和P2。构建的与rnb基因的转录和翻译lacZ报告基因融合体显示，rnb近端启动子P2比P1更强。然而，P2在体外不转录，这表明体内需要一个额外的因子。rnb转录本的3'端定位于翻译区域后的一个茎环结构处。
