Nordström K, Wagner E G, Persson C, Blomberg P, Ohman M
Department of Microbiology, University of Uppsala, Sweden.
Gene. 1988 Dec 10;72(1-2):237-40. doi: 10.1016/0378-1119(88)90148-5.
Control of replication of plasmids involves two processes: measurement of the copy number of the plasmid and adjustment of the replication frequency accordingly. For both these processes IncFII plasmids use an antisense RNA (CopA RNA) that forms a duplex with the upstream region (CopT) of the mRNA of the rate-limiting RepA protein. The kinetics of duplex formation was measured in vitro for the wild type and for a cop mutant plasmid; the mutant showed a reduction in the second-order rate constant for the formation of the RNA duplex and a similar increase in copy number. Hence, the kinetics of duplex formation and the concentration of CopA RNA determines the copy number of the plasmid.
测量质粒的拷贝数并相应地调整复制频率。对于这两个过程，IncFII质粒使用一种反义RNA（CopA RNA），它与限速RepA蛋白的mRNA的上游区域（CopT）形成双链体。在体外测量了野生型和cop突变体质粒双链体形成的动力学；该突变体显示RNA双链体形成的二级速率常数降低，拷贝数有类似增加。因此，双链体形成的动力学和CopA RNA的浓度决定了质粒的拷贝数。
