Fig 1: TREX2 caused polymerase slippage-induced mutations in MMR-mutant ESCs and in human-cancer-derived cells(A–F) Polymerase slippage was measured with a puro reporter with the following out-of-frame inserts: (A)10, (T)11, (T)10, (GT)5, (GT)4, and (AC)5.(G) Polymerase slippage was measured in human-derived cancer cells. A GFP(A)10 reporter was transfected into HCT116 cells, derived from human colorectal carcinoma (ATCC CCL-247), shown on the left. A Luciferase(A)10 reporter was transfected into SK-OV-3 cells, derived from ovarian adenocarcinoma (ATCC HTB-77), and into CCRF-CEM (ATCC CCL-199) cells, derived from acute lymphoblastic leukemia, shown in the middle and right, respectively.(H) RAD18 deletion reduced polymerase slippage of puro(A)10. Statistics for (A)–(D) are the average of three replicates using the unpaired Student’s t test and are listed in the text; mean ± SD; n = 3.