Fig 1.

Schematic representation of the core sets of conserved genes of SXT/R391 ICEs (A) and MGIs (B). Vertically hatched open reading frames indicate the integration sites of the elements (prfC for SXT/R391 ICEs and yicC for MGIs). Black open reading frames represent genes involved in site-specific excision and integration. Light gray open reading frames represent genes encoding the conjugative transfer machinery. Dark gray open reading frames correspond to genes involved in regulation (setCDR), and white open reading frames represent genes of unknown function. oriTs are represented by horizontal gray arrowheads. Hot spots for insertion of variable DNA are indicated by black arrowheads pointing upward.