FasX inhibits PrtF1 and PrtF2 expression at the level of mRNA translation. (A) Schematic showing the individual components of each of the three constructed chimeric mRNAs. (B) Western blot analyses of in vitro translation reactions (rxn). A total of 10 pmol of prtF1.FLAG, prtF2.FLAG, or spd.FLAG mRNA was preincubated with 50 pmol of RNA composed of different ratios of FasX and the deletion mutant derivative FasXΔ72-77. Following the in vitro translation reactions, the products were used in Western blot analysis. In lanes 1 to 5, the ratios of FasXΔ72-77 to FasX (in picomoles) present in the reaction mixtures were 50:0, 40:10, 25:25, 10:40, and 0:50, respectively. The spd.FLAG mRNA was used as a negative control for FasX-mediated regulation. Ab, antibody.