We used SEUSS12 to overexpress the mutant RUNX1 library in K562, a CML cell line with WT RUNX1.65 We generated a clonal K562 cell line with doxycycline-inducible CRISPRi knockdown of endogenous RUNX1 (iRUNX1-KD K562) and measured 67% reduction in RNA and 72% reduction in protein expression by qRT-PCR and western blot, respectively (Figures S2A–S2C). Here, RUNX1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.