Broad host range plasmid RK2 encodes multiple kil genes potentially lethal to Escherichia coli host cells.

Abstract

Cloning of specific regions of [plasmid] RK2, a broad host range incompatibility group P plasmid, has revealed 3 genes: kilA, kilB and kilC. Each of these genes can cause loss of viability of an E. coli host. This effect on the host is normally prevented by the functions of 3 additional RK2 genes: korA, korB and korC. Each kor gene is specific for a particular kil gene. The kil and kor genes are located in 4 distinct regions of the RK2 genome. The 3 kil genes are not clustered and, with the possible exception of kilA, they are also well separated from their corresponding kor genes. The kilA and korB determinants are not peculiar to RK2 but instead are highly conserved throughout the incompatibility group P plasmids.