“…Human Rad18 contains a putative SAP-box (39), a domain recently recognized to mediate the binding of certain proteins to specific A/T-rich DNA regions known as the scaffold attachment regions (SAR) (40). Interestingly, PARP-1, Ku antigens, and HMG-I/Y, which are involved in retroviral integration (7,12,13,41), have all been found to be SARbinding proteins (42)(43)(44). An intriguing possibility is that the molecules relevant for HIV-1 integration cluster together, perhaps in the vicinity of SARs, achieving in this way the coordination required for these complex reactions.…”