Dynamic changes in chromatin structure are essential for efficient DNA processing such as transcription replication and DNA repair Histone modifications and ATP-dependent chromatin remodeling are important for the alteration of chromatin structure The INO80 chromatin remodeling complex plays an important role in HR-mediated repair of DNA double-strand breaks (DSBs) In yeast the INO80 complex is recruited to the sites of DSBs via direct interaction with phosphorylated histone H2A and facilitates the processing of DSB ends However the function of the mammalian INO80 complex in DNA repair is mostly unknown Here we show that the mammalian INO80 complex is recruited to the laser-Induced DNA damage sites in a phosphorylated H2AX (gamma H2AX)-independent manner We also found that an actin-related protein ARP8 is an important subunit that is required for the recruitment of the mammalian INO80 complex to the DNA damage sites although the recruitment of the yeast INO80 complex requires its Nhp10 or Arp4 subunits These results suggest that the mammalian INO80 complex is also recruited to DNA damage sites similarly to the yeast INO80 complex but the mechanism of this recruitment may be different from that of the yeast INO80 complex These findings provide new insights Into the mechanisms of DNA repair in mammalian cells (C) 2010 Elsevier Inc All rights reserved