Open AccessLocalization and Characterization of a Gene on the ColE3-CA38 Plasmid that Confers Immunity to Colicin E8
Author(s) -
KinFu Chak,
Richard James
Publication year - 1984
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-130-3-701
Subject(s) - colicin , plasmid , biology , transposable element , escherichia coli , immunity , gene , genetics , mutant , microbiology and biotechnology , immune system
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.