Site-specific recombination of the circular 2um-like plasmid pKD1 requires the integrity of the recombinase gene A and of the partitioning genes B and C

In the circular plasmid pKD1, which stably replicates in Kluyveromyces lactis, the three open reading frames encode a site-specific recombinase (gene A) and two proteins involved in mitotic stability (genes B and C). A recombination analysis of plasmids in which gene B or C is inactivated reveals that unlike the 2,m plasmid of Saccharomyces cereisiae, these genes are also required for the site specificity of plasmid recombination.