SPI1 and infection: SPI1-mediated loss of H3K27me3 was further explored in cells infected with Salmonella mutants of hilA (ΔhilA) and hilD (ΔhilD), strains deficient for regulators of SPI1 effector protein expression.40,41 Infection with ΔhilA or ΔhilD did not show any decrease in H3K27me3 levels (Figure 3d) but showed increased expression of KDM6B compared with control group (Figure 3e).