Jacob A E, Cresswell J M, Hedges R W, Coetzee J N, Beringer J E
Mol Gen Genet. 1976 Sep 23;147(3):315-23. doi: 10.1007/BF00582883.
Plasmids have been constructed by insertion of DNA from Rhizobium leguminosarum or Proteus mirabilis into RP4 (an R factor of group P). Such recombinant plasmids retain the wide host range of the parental plasmid, being as efficiently transmissible as the unmodified RP4 and are stably maintained in rapidly growing cultures. The recombinant plasmids, even though each contained a DNA sequence absolutely identical with that of the host strain, are no more efficient at mobilizing the transfer of chromosomal genetic information from that host strain than was unmodified RP4. We therefore conclude that an unknown factor must be essential in the process of chromosome mobilization and rate limiting for that process.
通过将来自豌豆根瘤菌或奇异变形杆菌的DNA插入RP4（P组的一种R因子）构建了质粒。这类重组质粒保留了亲本质粒的广泛宿主范围，其传播效率与未修饰的RP4一样高，并且在快速生长的培养物中能稳定维持。这些重组质粒，尽管每个都包含与宿主菌株完全相同的DNA序列，但在促进来自该宿主菌株的染色体遗传信息转移方面，并不比未修饰的RP4更有效。因此我们得出结论，一个未知因素在染色体转移过程中必定是必不可少的，并且是该过程的速率限制因素。
