title: The repABC plasmid family.
abstract: repABC plasmids are widely distributed among alpha-proteobacteria. They are especially common in Rhizobiales. Some strains of this bacterial order can contain multiple repABC replicons indicating that this plasmid family includes several incompatibility groups. The replication and stable maintenance of these replicons depend on the presence of a repABC operon. The repABC operons sequenced to date share some general characteristics. All of them contain at least three protein-encoding genes: repA, repB and repC. The first two genes encode proteins involved in plasmid segregation, whereas repC encodes a protein crucial for replication. The origin of replication maps within the repC gene. In contrast, the centromere-like sequence (parS) can be located at various positions in the operon. In this review we will summarize current knowledge about this plasmid family, with special emphasis on their structural diversity and their complex genetic regulation. Finally, we will examine some ideas about their evolutionary origin and trends.
authors.affiliation: Programa de Genómica evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico. mac@ccg.unam.mx
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Cevallos
authors.forename: Ramón
authors.initials: R
authors.lastname: Cervantes-Rivera
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Gutiérrez-Ríos
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics; D005810:Multigene Family; D010957:Plasmids / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; C048817:RepB protein, Bacteria; C043650:RepC protein, Staphylococcus aureus; D015534:Trans-Activators; C045264:replication initiator protein; D004265:DNA Helicases