 This central domain allows recruitment of XRCC1 to polymeric ADP-ribose that forms on PARP1 after PARP1 binds to single strand breaks.The first linker contains a nuclear localization sequence and also has a region that interacts with DNA repair protein REV1, and REV1 recruits translesion polymerases.The second linker interacts with polynucleotide kinase phosphatase ( PNKP) (that processes DNA broken ends during base excision repair), aprataxin (active in single-strand DNA repair and non-homologous end joining) and a third protein designated aprataxin- and PNKP-like factor.