To identify conserved negative regulators of MHC-I expression, we performed a positive selection flow cytometry-based whole genome CRISPR/Cas9 screen in K-562 cells (Figure 1A), a well-characterized erythroleukemia line that lacks cell surface expression of all classical HLA alleles in the absence of IFN-γ stimulation (Figure 1B). Here, IFNG is linked to erythroleukemia.