The INO80 Chromatin Remodeling Complex

This chapter reviews the research of how INO80 complex was identified, what components it has, and how it participates in chromatin dynamics to maintain genomic integrity. The INO80 complex belongs to a subfamily of chromatin remodeling complexes and this subfamily is evolutionarily conserved from yeast to human. Rvb1 and Rvb2 have been identified as subunits of multi-protein complexes, such as INO80, SWR1, and p400, which are involved in diverse cellular processes, including DNA damage response, transcriptional regulation, and small nucleolar RNA accumulation. The function of the INO80 complex is best characterized in gene transcriptional regulation. In addition, INO80 is also the most extensively studied ATP dependent complex in DSB (double-strand break) repair. Recently, it was also revealed to be important for checkpoint regulation and DNA replication, especially under replication stress. It has been further demonstrated by in vitro biochemical assays that the INO80 complex exhibits DNA binding ability with binding constant at about 10 nM and ATP dependent mononucleosome mobilization activity with a distinct mechanism compared to Drosophila NURF remodeling complex. Recent research has illustrated the importance and the direct involvement of the INO80 chromatin remodeling complex in several essential nuclear processes, including transcriptional regulation, DNA repair, recombination, and replication.