Interactions among Trypanosoma brucei RAD51 paralogues in DNA repair and antigenic variation

摘要: Homologous recombination in Trypanosoma brucei is used for moving variant surface glycoprotein (VSG) genes into expression sites during immune evasion by antigenic variation. A major route such VSG switching gene conversion reactions which RAD51, a universally conserved recombinase, catalyses homology-directed strand exchange. In any eukaryote, RAD51-directed exchange vivo mediated further factors, including RAD51-related proteins termed Rad51 paralogues. These appear to be ubiquitously conserved, although their detailed roles remain unclear. T. brucei, four putative RAD51 paralogue have been identified sequence homology. Here we show that all paralogues act DNA repair, and subnuclear dynamics, though not equivalently, while mutation of only one significantly impedes switching. We also the interact, complexes they form may explain distinct phenotypes mutants as well observed interdependency. Finally, document are encoded wide range protists, demonstrating repertoire unusually large among microbial eukaryotes member protein family corresponds with key, eukaryotic paralogue.