INCOMPATIBILITY PROPERTIES OF THE NARROW-HOST-RANGE LACTOCOCCAL PLASMID PCI305

The cryptic plasmid pCI305 from Laetococcus lactis subsp. lactis UC317 was screened for incompatibility with a range of cloning vectors and was found to be incompatible with the theta-replicating plasmids pAM40 1 and pIL253. In contrast, lactococcal vectors containing the replicat ion functions of the rolling circle replicating plasmids pSH71 and pWV 01 were compatible with pCI305. A number of native lactococcal plasmid s were also screened for both incompatibility and DNA sequence homolog y to the pCI305 replicon. A plasmid with high sequence identity was id entified which was compatible with pCI305.