质粒RSF1010寄主范围特性的遗传学分析

采用Tn5插入诱变、限制性核酸内切酶作图以及DNA转化等方法，对广泛寄主范围型质粒SF 1010的衍生体－pKT 2 40进行研究。证实质粒的寄主围决定于它在遗传背景不同的寄主中复制并保存自身的能力，而repA，rcpB和repC基因为该质拉复制所必需。

Genetic analysis of the host range of the plasmid RSF1010

32 host range mutants of pMO58, which contains a 8.0 kb fragment of RSF1010, were screened, using the transposon Tn5 insertion mutagenesis. To judge the genes which affect the host range of plasmid, the Tn5 insertion sites were located with restriction endonuclease mapping. The ability of the plasmid replication in different recipients was checked with DNA transformation. The results further confirmed the barrier to the host range of plasmid was their inability to replicate and maintain themselves in genetically different host. The repA repB and repC genes were necessary for the plasmid replication, but the repC gene may be a positive regulator and its function may be complemented by host gene products.