Chromatin responses to DNA damage

The preservation of genome stability depends upon tightly regulated mechanisms that continuously search the genome for irregularities that, if left ignored, could be dangerous to both the genomic integrity and cell survival. These mechanisms are mediated by a multiplicity of proteins and factors that physically approach the DNA to either search for the damage or to fix it. Therefore, in eukaryotic cells, where the DNA molecule is tightly packed into nucleosomes forming a highly compacted structure, the chromatin, access of these factors to the DNA molecule represents an additional step, as well as an opportunity for extra regulatory mechanisms. Although a plethora of information has been accumulated over the past years on the factors and mechanisms involved in the response to DNA damage, very little is known about the role of the chromatin structure itself on the DNA damage response (DDR). Interestingly, several remodeling complexes have recently been described to be involved in the DNA damage response. In particular, the INO80 remodeling complex seems to be involved in several aspects of the DDR response. Thus, this chapter will describe the novel roles of the INO80 remodeling complex in DNA damage tolerance, double strand break repair (DSB) and telomere maintenance.