L. monocytogenes listeriolysin gene (hly) and the two adjacent operons: the plcA-prfA operon and the lecithinase operon. prfA
encodes a positive regulatory factor, picA encodes a phosphatidylinositol-specific phospholipase C, mpl encodes a metalloprotease, actA
encodes a surface protein necessary for actin assembly, and plcB encodes a lecithinase.