FIG. 8.
Effect of a loss-of-function mutation in sicA on the expression of sopE. The levels of β-galactosidase in the S. enterica serovar Typhimurium strain SB876, which carries a sopE::lacZ gene fusion, and its isogenic derivative strains SB879 and SB1235, which carry loss-of-function mutations in sicA or in sicA and sipC, respectively, were measured as described in Materials and Methods. Activity is expressed as percentage of wild-type activity, which was considered 100. As negative controls, levels of β-galactosidase were measured in the S. enterica serovar Typhimurium strain SB804, which carries a sitB::lacZ gene fusion (wild type), and its isogenic derivative strains of SB1234, which carry loss-of-function mutations in sicA.