FIG. 6.

Posttranscriptional regulation of FatA protein levels in 531A-10. FatA (A) and FatB (B) protein levels were assessed by Western blotting of total membrane fractions and fatA (C) and fatB (D) transcript levels assessed from total RNA using an RNase protection assay. Strains analyzed were as follows and were the same in all four panels: lanes 1 and 2, 531A (wild-type parent); lane 3, 531A-10 (rmlD mutant). Cells in lane 1 were grown using iron-sufficient conditions (10 μg/ml ferric ammonium citrate), while cells in lanes 2 and 3 were grown using iron-deficient conditions (20 μM EDDA). The size of each of the protected riboprobes is given in nucleotides. The three unprotected riboprobes are shown in lane P. The fatA and fatB full-length riboprobes resolve as a single band at approximately 220 nucleotides, while the ompU probe is 90 nucleotides in length. The ompU mRNA was used as an internal control to asses mRNA loading and quality.