A parA homolog selectively influences positioning of the large chromosome origin in Vibrio cholerae.

A Vibrio cholerae deletion mutant lacking VS2773, a parA partitioning gene homolog located in a parAB operon on the large chromosome, displays altered positioning of the large chromosome origin. Deletion of a second parA homolog on the large chromosome (VC2061) does not affect its origin positioning. The origin position of the small chromosome is unchanged by either or both of these deletions, suggesting that VC2773 function is specific to the replicon on which it is carried. VC2773 and VC2772 form a parABS system with inverted repeats found near the large chromosome origin.