Dobson M J, Yull F E, Molina M, Kingsman S M, Kingsman A J
Department of Botany, University of Nottingham, University Park, UK.
Nucleic Acids Res. 1988 Jul 25;16(14B):7103-17. doi: 10.1093/nar/16.14.7103.
The effect of the yeast 2 micron circle encoded REP1 and REP2 gene products on plasmid partitioning and copy number control was analyzed by removing the open reading frames from their normal sequence context and transcriptional control regions and directing their expression using heterologous promoters in [cir0] host strains. Both the REP1 and REP2 gene products are directly required at appropriate levels of expression to reconstitute the 2 microns circle partitioning system in conjunction with REP3 and the origin of replication. The level of expression of REP2 appears to be critical to re-establishing proper partitioning and may also play a role in monitoring and thereby regulating the plasmid copy number. Constitutive expression of the REP1 and REP2 open reading frames using heterologous expression signals can be used to reconstruct efficient plasmid partitioning even in the absence of FLP-mediated plasmid amplification and a functional D open reading frame.
通过从其正常序列背景和转录控制区域中去除开放阅读框，并在[cir0]宿主菌株中使用异源启动子指导其表达，分析了酵母2微米环编码的REP1和REP2基因产物对质粒分配和拷贝数控制的影响。REP1和REP2基因产物在适当的表达水平下都是直接必需的，以便与REP3和复制起点一起重建2微米环分配系统。REP2的表达水平似乎对于重新建立正确的分配至关重要，并且可能在监测并由此调节质粒拷贝数方面也发挥作用。即使在没有FLP介导的质粒扩增和功能性D开放阅读框的情况下，使用异源表达信号组成型表达REP1和REP2开放阅读框也可用于重建有效的质粒分配。
