. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "xrcc4_human"^^ . "XRCC4"^^ . "X-ray repair cross-complementing protein 4"^^ . . . . . . . . . "DNA repair protein XRCC4"^^ .