Adams C W, Rosenberg M, Hatfield G W
J Biol Chem. 1985 Jul 15;260(14):8538-44.
The precise points of in vivo transcription initiation and termination in the leader region of the ilvGEDA operon of Escherichia coli K12 have been determined. Leader RNA transcription products from either side of the attenuator have been identified and quantitated by T1 fingerprint analyses under growth conditions which affect operon expression. The results provide in vivo confirmation of the ilvGEDA attenuation model. Previous DNA sequence and in vitro transcription analyses have demonstrated that this operon is preceded by two strong in vitro promotors. The studies reported here show that transcription is initiated in vivo only from the downstream promotor and that no detectable in vivo expression from the upstream promotor is observed under conditions which affect operon regulation.
已确定大肠杆菌K12的ilvGEDA操纵子前导区体内转录起始和终止的精确位点。在影响操纵子表达的生长条件下，通过T1指纹分析鉴定并定量了来自弱化子两侧的前导RNA转录产物。这些结果为ilvGEDA衰减模型提供了体内证据。先前的DNA序列和体外转录分析表明，该操纵子之前有两个强大的体外启动子。本文报道的研究表明，体内转录仅从下游启动子起始，并且在影响操纵子调控的条件下，未观察到上游启动子有可检测到的体内表达。
