Ebina Y, Nakazawa A
J Biol Chem. 1983 Jun 10;258(11):7072-8.
We have analyzed the initiation and termination sites of transcription in vivo of the colicin E1 gene in Escherichia coli cells by S1-mapping assay and RNA blot hybridization. According to the S1-mapping assay, the transcription was initiated at about 75 base pairs upstream from the NH2-terminal codon of the gene. The initiation site corresponded with one of the two promoters which were previously determined by in vitro transcription experiments (Ebina, Y., Kishi, F., Miki, T., Kagamiyama, H., Nakazawa, T., and Nakazawa, A. (1981) Gene 15, 119-126). Transcription in vivo of the colicin E1 gene was stimulated by cyclic AMP in the adenylate cyclase-defective mutant cells. Two transcripts of the colicin E1 gene, approximately 1700 and 2200 nucleotides, were detected by the blot hybridization. Since initiation of the transcription started at one site in vivo, these results indicated two termination sites. The location of the termination sites were approximately 60 and 560 base pairs downstream from the COOH-terminal codon of the gene as judged by S1-mapping assay. In vitro transcription experiments with rho-factor strongly suggested that the termination in the proximal terminator was rho-dependent. In the terminator structure, there is the sequence CAAACAAA which is homologous to a common sequence CAATCAA found in other rho-dependent terminators.
我们通过S1核酸酶图谱分析和RNA印迹杂交，分析了大肠杆菌细胞中大肠杆菌素E1基因在体内转录的起始和终止位点。根据S1核酸酶图谱分析，转录起始于该基因氨基末端密码子上游约75个碱基对处。该起始位点与先前通过体外转录实验确定的两个启动子之一相对应（Ebina，Y.，Kishi，F.，Miki，T.，Kagamiyama，H.，Nakazawa，T.，以及Nakazawa，A.（1981年）《基因》15卷，第119 - 126页）。在腺苷酸环化酶缺陷型突变细胞中，大肠杆菌素E1基因的体内转录受到环磷酸腺苷的刺激。通过印迹杂交检测到大肠杆菌素E1基因的两种转录本，分别约为1700和2200个核苷酸。由于转录起始于体内的一个位点，这些结果表明存在两个终止位点。根据S1核酸酶图谱分析判断，终止位点位于该基因羧基末端密码子下游约60和560个碱基对处。用ρ因子进行的体外转录实验强烈表明，近端终止子的终止是ρ因子依赖性的。在终止子结构中，存在序列CAAACAAA，它与在其他ρ因子依赖性终止子中发现的共同序列CAATCAA同源。
