Hansen F G, Atlung T
Department of Microbiology, Technical University of Denmark, Lyngby.
Mol Microbiol. 1995 Jan;15(1):149-54. doi: 10.1111/j.1365-2958.1995.tb02229.x.
The kinetics of initiation of chromosome replication after induction of DnaA protein synthesis was studied in a dnaA(nuII) rnh mutant of Escherichia coli. DnaA protein synthesis was induced to different extents using the wild-type dnaA gene controlled by a lac promoter. Initiation of chromosome replication from oriC, measured as an increase in origin to terminus ratio, took place at different times after addition of an inducer dependent on the DnaA protein synthesis rate. The first initiations always occurred when DnaA protein had accumulated approximately to the average wild-type concentration (24 ng of DnaA protein per ml cells at OD450 = 1.0). At a low DnaA protein accumulation rate one synchronous round of replication was obtained after 30 min of induction. The initiation kinetics obtained when DnaA protein accumulated rapidly was complicated and indicated that other factors might also be involved.
在大肠杆菌的dnaA(nuII) rnh突变体中研究了诱导DnaA蛋白合成后染色体复制起始的动力学。使用由lac启动子控制的野生型dnaA基因，将DnaA蛋白合成诱导到不同程度。以oriC处染色体复制的起始为指标，通过测量起始点与终点比例的增加来衡量，在添加诱导剂后的不同时间发生起始，这取决于DnaA蛋白的合成速率。首次起始总是在DnaA蛋白积累到大约平均野生型浓度时发生（在OD450 = 1.0时，每毫升细胞中有24 ng DnaA蛋白）。在低DnaA蛋白积累速率下，诱导30分钟后获得一轮同步复制。当DnaA蛋白快速积累时获得的起始动力学很复杂，表明可能还涉及其他因素。
