FIG 8.

Transcription of the genes encoding the F. tularensis Lon substrates in LVS and its isogenic Δlon mutant. The parent strain (WT) or its Δlon mutant (ST1120) containing an episomal tetracycline-inducible copy of the target gene (on the pEDL17 shuttle plasmid) was grown to an OD₆₀₀ of 0.6 in CDM in the presence of hygromycin (200 μg/ml) at 37°C before being treated with the tetracycline analog ATc for 4 h. The total RNA samples were purified from each pair of LVS and ST1120 carrying the same expression construct of clpX (A), FTL578 (B), FTL663 (C), FTL1957 (D), FTL1217 (E), or FTL1228 (F). The mRNA level of each target gene in the presence (filled bars) or absence (open bars) of ATc was quantified by qRT-PCR, normalized on the basis of the helicase gene, and presented as the mean level ± SEM (n = 3).