Holliday junction-binding activity of human SPF45

Naoki Horikoshi, Yuichi Morozumi, Motoki Takaku, Yoshimasa Takizawa, Hitoshi Kurumizaka*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


SPF45 is considered to be a bifunctional protein that functions in splicing and DNA repair. A previous genetic study reported that Drosophila SPF45 participates in the DNA-repair pathway with a RAD51-family protein, RAD201, suggesting that SPF45 may function in DNA repair by the homologous-recombination pathway. To study the function of SPF45 in homologous recombination, we purified human SPF45 and found that it preferentially binds to the Holliday junction, which is a key DNA intermediate in the homologous-recombination pathway. Deletion analyses revealed that the RNA recognition motif, which is located in the C-terminal region of human SPF45, is not involved in DNA binding. On the other hand, alanine-scanning mutagenesis identified the N-terminal lysine residues, which may be involved in Holliday junction binding by human SPF45. We also found that human SPF45 significantly binds to a RAD51 paralog, RAD51B, although it also binds to RAD51 and DMC1 with lower affinity. These biochemical results support the idea that human SPF45 functions in DNA repair by homologous recombination.

Original languageEnglish
Pages (from-to)373-383
Number of pages11
JournalGenes to Cells
Issue number4
Publication statusPublished - 2010 Apr

ASJC Scopus subject areas

  • Genetics
  • Cell Biology
  • Medicine(all)


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