To examine ATXN3’s association with PNKP, we immunoprecipitated (IP’d) PNKP and ATXN3 separately from the nuclear extract (NE, benzonase treated to remove DNA and RNA to avoid DNA-mediated co-immunoprecipitation) of human HEK-293 (human embryonic kidney cell line) (Figs. 2A and B) and SH-SY5Y (a human neuroblastoma cell line) cells (S2A and S2B Figs.) using the respective anti-protein (PNKP or ATXN3) antibody (Ab). Here, PNKP is linked to neuroblastoma.