Controlled Integration into the Lactococcus Chromosome of the pCI829-Encoded Abortive Infection Gene from Lactococcus lactis subsp. lactis UC811

Judy Casey, Charles Daly, Gerald F. Fitzgerald
1992 Applied and Environmental Microbiology  
The phage insensitivity gene of lactococcal plasmid pCI829 which encodes an abortive infection defense mechanism (Abi) was inserted into the Lactococcus lactis subsp. lactis CH919 chromosome by utilizing the integration plasmid pCI194, which contains 4.2 kb of homology with the conjugative transposon Tn919. Chloramphenicol-resistant transformants expressed phage insensitivity to the prolate-headed phage c2 and the small isometric-headed phage 712, and hybridization analysis indicated that
more » ... ndicated that transformants contained pCI194 integrated in single copy. The level of phage insensitivity expressed by the transformants was reduced from that observed when the abi gene was located on a replicating plasmid, as determined by plaque assay and burst size Southern hybridization analysis. Chromosomal DNA (0.5 3283 on May 5, 2020 by guest Downloaded from 3284 CASEY ET AL. on May 5, 2020 by guest
doi:10.1128/aem.58.10.3283-3291.1992 fatcat:plw4xqylxzb6hblqmogm5ri7ni