SWIM Domain Containing Srs2 Interacting Protein 1 (SWS1)

Rad52-dependent homologous recombination (HR) is regulated by the antirecombinase activities of Srs2 and Rqh1/Sgs1 DNA helicases in fission yeast and budding yeast. Sws1, a novel HR protein with a SWIM-type Zn finger. Inactivation of Sws1 suppresses the genotoxic sensitivity of srs2 and rqh1 mutants and rescues the inviability of srs2 rqh1 cells. Sws1 functions at an early step of recombination in a pro-recombinogenic complex with Rlp1 and Rdl1, two RecA-like proteins that are most closely related to the human Rad51 paralogs XRCC2 and RAD51D, respectively. This finding indicates that the XRCC2–RAD51D complex is conserved in lower eukaryotes. A SWS1 homolog exists in human cells. It associates with RAD51D and ablating its expression reduces the number of RAD51 foci.