title: Human PSF binds to RAD51 and modulates its homologous-pairing and strand-exchange activities.
abstract: RAD51, a eukaryotic recombinase, catalyzes homologous-pairing and strand-exchange reactions, which are essential steps in homologous recombination and recombinational repair of double strand breaks. On the other hand, human PSF was originally identified as a component of spliceosomes, and its multiple functions in RNA processing, transcription and DNA recombination were subsequently revealed. In the present study, we found that PSF directly interacted with RAD51. PSF significantly enhanced RAD51-mediated homologous pairing and strand exchange at low RAD51 concentrations; however, in contrast, it inhibited these RAD51-mediated recombination reactions at the optimal RAD51 concentration. Deletion analyses revealed that the N-terminal region of PSF possessed the RAD51- and DNA-binding activities, but the central region containing the RNA-recognition motifs bound neither RAD51 nor DNA. These results suggest that PSF may have dual functions in homologous recombination and RNA processing through its N-terminal and central regions, respectively.
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Morozumi
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takizawa
authors.forename: Motoki
authors.initials: M
authors.lastname: Takaku
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurumizaka
mesh_terms: D020029:Base Pairing; D001665:Binding Sites; D001667:Binding, Competitive; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D000072670:PTB-Associated Splicing Factor; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D051135:Rad51 Recombinase / Q000378:metabolism*; D011995:Recombination, Genetic
chemical_list: D004277:DNA, Single-Stranded; D000072670:PTB-Associated Splicing Factor; D016601:RNA-Binding Proteins; D012313:RNA; D004247:DNA; C495153:RAD51 protein, human; D051135:Rad51 Recombinase