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Holliday junction–binding activity of human SPF45
Author(s) -
Horikoshi Naoki,
Morozumi Yuichi,
Takaku Motoki,
Takizawa Yoshimasa,
Kurumizaka Hitoshi
Publication year - 2010
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/j.1365-2443.2010.01383.x
Subject(s) - holliday junction , homologous recombination , rad51 , biology , dna , dna repair , branch migration , non homologous end joining , genetics , replication protein a , genetic recombination , microbiology and biotechnology , dna binding protein , gene , recombination , transcription factor
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.