Abstract
DNA double strand breaks need to be repaired in an organized fashion to preserve genomic integrity. In the organization of faithful repair, histone ubiquitination plays a crucial role. Recent findings suggest an integrated model for DNA repair regulation through site-specific histone ubiquitination and crosstalk to other posttranslational modifications. Here we discuss how site-specific histone ubiquitination is achieved on a molecular level and how different multi-protein complexes work together to integrate different histone ubiquitination states. We propose a model where site-specific H2A ubiquitination organizes the spatio-temporal recruitment of DNA repair factors which will ultimately contribute to DNA repair pathway choice between homologous recombination and non-homologous end joining.