Characterization of interaction of C- and N-terminal domains in LIM15/DMC1 and RAD51 from a basidiomycetes, Coprinus cinereus.

Both LIM15/DMC1 and RAD51 are thought to be essential for meiosis in which homologous chromosomes pair and recombine. The primary purpose of the present study was to investigate the homotypic and heterotypic interactions among their terminal domains. We prepared cDNAs and recombinant proteins of the full-length, N-terminal, and the C-terminal domains of LIM15/DMC1 (CoLIM15) and RAD51 (CoRAD51) from the basidiomycete Coprinus cinereus. In both two-hybrid assay in vivo and pull-down assay in vitro, either CoLim15 or CoRad51 interacted homotypically between the C-terminal domains, respectively, but no heterotypic interaction was observed between CoLim15 and CoRad51. The N-terminal domain of CoLim15 bound to ssDNA and dsDNA, while the C-terminal domain of CoRad51 appeared to interact weakly with ssDNA. Based on these results, the interaction among the strand-exchange proteins and meiosis was discussed. Copyright 2000 Academic Press.