Abstract
The maintenance of genome stability requires the coordinated actions of multiple proteins and protein complexes. One critical family of proteins is the recombination mediators. Their role is to facilitate the formation of recombinase nucleoprotein filaments on single-stranded DNA (ssDNA). Filament formation can take place on post-replicative ssDNA gaps as well as on 3'-tailed duplexes resulting from helicase-nuclease processing. In prokaryotes, the RecF, O, and R proteins are widely distributed and mediate RecA loading as either the RecFOR or RecOR complexes, depending on the species being studied. In this review, I compare and contrast the available biochemical and structural information to provide insight into the mechanism of action of this critical family of mediators.