(c) HeLa cells transfected with vectors encoding GFP-IRGMd versus GFP-IRGMdS47N and YFP-IRGMb (vector encoding GFP only was transfected as a control) were stained with 7-AAD after 48 h, and percentages of GFP+ (for IRGMd and IRGMS47N) or YFP+ (for IRGMb) cells that were also 7-AAD+ were quantified. 