FIG. 3.
Production of chromosomally encoded IpaH proteins is activated by MxiE and IpgC. Whole-cell extracts of BS176 (a virulence plasmid-cured derivative of wild-type S. flexneri strain M90T), its derivatives harboring plasmid pKH128 (which expresses IpgC), plasmid pMM71 (which expresses MxiE), or both plasmids, and SF1076 (an ipaB mutant) were analyzed by SDS-PAGE and probed with rabbit anti-IpaH serum. The positions of IpaH and protein X (a constitutively expressed, chromosomally encoded protein recognized by rabbit anti-IpaH serum) are indicated.