FIGURE 1.

Control of Y. enterocolitica YopQ production and type III secretion by three classes of genes. Y. enterocolitica W22703 and its variants yopN (class I), yopD (class II), yscN (class III), yopN/yopD (class I/II), yopN/yscN (class I/III), and yopD/yscN (class II/III) and as well as Y. enterocolitica W22703 (pYV⁻) with plasmid pyopQ were analyzed for the production of YopQ and the type III secretion of YopQ. Cultures were grown in the presence of 5 mm CaCl₂ (secretion non-permissive) or 5 mm EGTA (secretion permissive) and centrifuged. Proteins in the supernatant (S) and Yersinia sediment (P) fractions were analyzed by immunoblotting for the presence of YopQ.