Aberrant regulation of iron-dependent gene expression.

<p>A)Western blot analysis of Irr was performed on wildtype, <i>bfr</i>, <i>mbfA</i> and <i>mbfA bfr</i> strains grown in GSY medium supplemented either with no added iron (-) or 5 μM FeSO₄ (+). The protein was detected using anti-Irr antibodies. The same blot was exposed for either 20 secs (upper panel) or 100 secs (Irr long), lower panel). GroEL was used as a control for a protein not regulated by iron, and it was detected using anti-GroEL antibodies. 15 μg of protein were loaded per lane. B) Cells of the wildtype, <i>bfr</i>, <i>mbfA</i> and <i>mbfA bfr</i> strains were grown in GSY medium supplemented with 5 μM FeSO₄. The steady-state transcript levels of <i>leuC</i>, <i>sdhC</i>, <i>acnA</i> and <i>sufC</i> were analyzed by qualitative real-time PCR. The data are expressed as relative starting quantities (<i>SQ</i>) of respective mRNAs normalized to the housekeeping gene <i>gapA</i> and are presented as average of three replicates ± S.D (<i>error bars</i>). An asterisk denotes a significant difference compared to the wild type based on Student’s <i>t</i> test using a confidence level of <i>p<</i>0.01.