Surprising dependence on postsegregational killing of host cells for maintenance of the large virulence plasmid of Shigella flexneri.

ABSTRACT: Low-copy-number plasmids all encode multiple systems to ensure their propagation, including replication, partition (active segregation), and postsegregational killing (PSK) systems. PSK systems kill those rare cells that lose the plasmid due to replication or segregation errors. PSK systems should not be used as the principle means of maintaining the plasmid. The metabolic cost of killing the many cured cells that would arise from random plasmid segregation is far too high. Here we describe an interesting exception to this rule. Maintenance of the large virulence plasmid of Shigella flexneri is highly dependent on one of its PSK systems, mvp, at 37 degrees C, the temperature experienced during pathogenesis. At 37 degrees C, the plasmid is very unstable and mvp efficiently kills the resulti

SUBMITTER: Sayeed S 

PROVIDER: S-EPMC1070380 | biostudies-literature | 2005 Apr

REPOSITORIES: biostudies-literature