Molecular characterization of a theta replication plasmid and its use for development of a two-component food-grade cloning system for Lactococcus lactis.

ABSTRACT: pCD4, a small, highly stable theta-replicating lactococcal plasmid, was used to develop a food-grade cloning system. Sequence analysis revealed five open reading frames and two putative cis-acting regions. None appears to code for undesirable phenotypes with regard to food applications. Functional analysis of the replication module showed that only the cis-acting ori region and the repB gene coding for the replication initiator protein were needed for the stable replication and maintenance of pCD4 derivatives in Lactococcus lactis. A two-component food-grade cloning system was derived from the pCD4 replicon. The vector pVEC1, which carries the functional pCD4 replicon, is entirely made up of L. lactis DNA and has no selection marker. The companion pCOM1 is a repB-deficient pCD4 derivative

SUBMITTER: Emond E 

PROVIDER: S-EPMC92788 | biostudies-literature | 2001 Apr

REPOSITORIES: biostudies-literature