Figure 1. A haploid genetic screen to identify genes required for cell surface expression of MHC-I molecules. A.

Schematic of the screen. B. Selecting MHC-I^low cells by FACS. Mutagenised KBM7 cells were labeled for surface MHC-I and those cells defective for MHC-I presentation enriched by two sequential rounds of FACS. The FACS plots correspond to the stages of the screen outlined above them in A. C. The genetic screen identifies multiple genes known to be involved in the MHC-I antigen presentation pathway. Important genes within the MHC-I antigen presentation pathway are targeted by multiple independent retroviral integrations (red triangles).