Stability function of plasmid ColK

[摘要] ColK is a multicopy naturally occurring plasmid, that is very stably maintained in bacterial host cells. This work shows that the plasmid encodes a stability determinant designated ckr. that is involved in promoting site-specific recombination in multimeric plasmids, efficiently converting them to monomers. This apparently ensures stability by maximizing the number of segregating units at cell division. ckr has been located to a 0.37 kb fragment in ColK, its DNA sequence is highly homologous with that of cer (stability determinant of ColE1, a related plasmid to ColK). Recombination has been found to occur both between directly repeated cer copies and a direct repeat of one copy of cer and one of ckr and results in the deletion of the internal fragment between them. Inversion has been shown to occur between two cer copies in inverted repeat and in a substrate containing a copy of cer and a copy of ckr in inverted repeat. Both deletion and inversion are highly efficient.

[发布机构] University:University of Glasgow

[关键词] Genetics