Mms19

Standard Western blotting procedures were used. Briefly, cultured cells were washed with 1X PBS then lysed with RIPA buffer supplemented with protease and phosphatase inhibitors (Sigma catalog number 5892791001 and 4906837001, respectively). Lysates were heat-denatured prior to loading onto 4–20% gels (Bio-Rad catalog number 567–1094) and detected with antibodies as detailed next. Proteintech: MMS19 (16015-1-AP, dilution 1/1000), FAM96B (20108-1-AP, dilution 1/500); ThermoFisher Scientific: DPYD Monoclonal Antibody (7D4) (H00001806-M01, dilution 1/1000); Cell Signaling: phospho-Chk2 S516 (2669S, dilution 1/1000), Chk1 (2360 S, dilution 1/1000), GAPDH (8884 S, dilution 1/1000), β-Actin (12620, dilution 1/2000); Abcam: phospho-Chk1 S296 (ab79758, dilution 1/500). All blots derive from the same experiment and were processed in parallel. Uncropped and unprocessed scans of western blots can be found in the Supplementary Information.

The Human Protein Atlas (HPA) [20 (link)] (https://www.proteinatlas.org/) has been developing of antibodies to human-encoded proteins, and the database includes a large number of immunohistochemical sections of normal and pathological human tissues and partial immunofluorescence sections of cells. The protein expression and intracellular localization of five genes were exhibited on the HPA platform. Western blotting was performed according to a previous study [21 (link)]. The following antibodies were used in this study: GAPDH (No. 60004-1-Ig, 1:10000 dilution, Proteintech, China), MMS19 (No: 66049-1-Ig, 1:1000 dilution, Proteintech, China), NOP14 (No:26854-1-AP, 1:500 dilution, Proteintech, China), POLRMT (No: A15605, 1:500 dilution, ABclonal, China), SNAPC5 (No:17272-1-AP, 1:500 dilution, Proteintech, China), and TIGD1 (No:13833-1-AP, 1:500 dilution, Proteintech, China).