NCCIT cells were transfected with plasmids encoding one of two types of shRNA against WRN, or shRNA against G9a, or one of two control plasmids (CV – empty vector, CS – vector control expressing a scrambled, non-targeting sequence, G(−) – G9a-deficient clone, 31–34, 61, and 62 – WRNp deficient clones, see Supplementary Table 3). Transfected cells were selected in puromycin and individual clones were isolated and subjected to western blotting analysis with a WRNp antibody or a γ-tubulin control.