INO80 and γ-H2AX Interaction Links ATP-Dependent Chromatin Remodeling to DNA Damage Repair

(Shen et al., 2000). However, it is not known whether the INO80 complex functions in DNA damage repair Waltham, Massachusetts 02454 directly or indirectly through other mechanisms. Here, we show biochemical and genetic evidence that the INO80 complex is directly involved in DNA repair. The Summary key mechanism is through a specific interaction between the INO80 complex and the DNA damage-While the role of ATP-dependent chromatin remodel-ing in transcription is well established, a link between induced ␥-H2AX. These results provide a direct link between ATP-dependent chromatin remodeling and DNA chromatin remodeling and DNA repair has remained elusive. We have found that the evolutionarily con-damage repair. served INO80 chromatin remodeling complex directly participates in the repair of a double-strand break Results (DSB) in yeast. The INO80 complex is recruited to a HO endonuclease-induced DSB through a specific in-Transcriptional and Checkpoint Responses to DNA teraction with the DNA damage-induced phosphory-Damage Are Normal in ino80 Mutant lated histone H2A (␥-H2AX). This interaction requires We first investigated whether the DNA repair defects Nhp10, an HMG-like subunit of the INO80 complex. The of the ino80 mutant could be attributed to defects in loss of Nhp10 or ␥-H2AX results in reduced INO80 re-transcriptional response to DNA damage or defects in DNA cruitment to the DSB. Finally, components of the INO80 damage checkpoint functions. We found that the major complex show synthetic genetic interactions with the DNA damage response pathway, the Mec1 kinase path-RAD52 DNA repair pathway, the main pathway for DSB way, appeared to be normal in the ino80-null mutant. In repair in yeast. Our findings reveal a new role of ATP-response to DNA damage, the transcription of ribonucleo-dependent chromatin remodeling in nuclear processes tide reductase genes RNR1 and RNR3, which are the and suggest that an ATP-dependent chromatin re-downstream targets of the DNA damage checkpoint gene modeling complex can read a DNA repair histone code. MEC1 (Huang and Elledge, 1997), is induced. We found that after treatment of ino80 cells with hydroxyurea (HU), Introduction the induction of RNR1 and RNR3 was normal (Figure 1A). In addition, ino80 mutant cells showed normal cell The packaging of the eukaryotic genome into chromatin cycle arrest in the presence of HU, consistent with func-restricts the access of DNA processing enzymes in vari-tioning DNA damage checkpoints (Figure 1B). Moreover, ous nuclear processes. To overcome these barriers, a survey of the global transcription profile of the ino80 cells use two major …