Chak K F, James R
J Gen Microbiol. 1984 Mar;130(3):701-10. doi: 10.1099/00221287-130-3-701.
Escherichia coli W3110 cells carrying the ColE3-CA38 plasmid are immune to externally added colicin E8, a newly described member of the E group colicins. By molecular cloning and transposon mutagenesis we localized the colicin E8 immunity gene between the EcoRI site (4.0 kb on the restriction map) and the PvuII site (3.68 kb) of the ColE3-CA38 plasmid. This placed the colicin E8 immunity gene between the colicin E3 immunity gene and lys, the region which determined mitomycin C sensitivity. Insertion of a transposon into the colicin E3 structural gene prevented the synthesis of active colicin and completely abolished mitomycin C sensitivity, but had no effect on the two immunity genes. In contrast, insertion of a transposon into the colicin E8 immunity gene had no effect upon colicin E3 production or colicin E3 immunity but did abolish mitomycin C sensitivity. The phenotype conferred by plasmids with a transposon inserted into the lys region of ColE3-CA38 was dependent upon the site of insertion.
携带ColE3 - CA38质粒的大肠杆菌W3110细胞对外部添加的大肠杆菌素E8具有免疫性，大肠杆菌素E8是E组大肠杆菌素中一个新描述的成员。通过分子克隆和转座子诱变，我们将大肠杆菌素E8免疫基因定位在ColE3 - CA38质粒的EcoRI位点（限制酶切图谱上为4.0 kb）和PvuII位点（3.68 kb）之间。这使得大肠杆菌素E8免疫基因位于大肠杆菌素E3免疫基因和lys之间，lys区域决定了丝裂霉素C敏感性。将一个转座子插入大肠杆菌素E3结构基因会阻止活性大肠杆菌素的合成，并完全消除丝裂霉素C敏感性，但对两个免疫基因没有影响。相反，将一个转座子插入大肠杆菌素E8免疫基因对大肠杆菌素E3的产生或大肠杆菌素E3免疫没有影响，但确实消除了丝裂霉素C敏感性。在ColE3 - CA38的lys区域插入转座子的质粒所赋予的表型取决于插入位点。
