Figure 5: Transcriptional activity of the hbo-yjbH promoter is affected by cspA.

(A) yjbH transcription in SH1000 wildtype, ΔcspA and ΔyjbH strains. RNA obtained from SH1000 wildtype, ΔcspA and ΔyjbH cells at various optical densities (15 μg per lane) was resolved on a denaturing agarose gel, blotted to Hybond XL membrane and hybridized with a 200-bp 32P-radiolabeled yjbH DNA fragment. The relative densitometric units (RDU) of the 1.9k and 1.2k nt bands were calculated relative to 1.2k nt levels in the wildtype at OD₆₅₀=0.7 (set at 100). The hybridization analysis was repeated twice with similar results. A representative blot was shown.

(B) hbo-yjbH promoter activity in S. aureus SH1000 strains deleted for cspA or yjbH. Cell density-normalized GFP fluorescence of S. aureus SH1000 wildtype, ΔcspA and ΔyjbH strains carrying the hbo-yjbH promoter reporter plasmid (pALC8134) at 4 and 10 hours of growth in TSB was shown. Cell densities were simultaneously measured at OD₆₅₀ and fluorescence normalized by it. The value for each strain represents the mean of two biological replicates that were read in triplicate, and the experiments were repeated three times. A representative experiment is displayed. The asterisks indicate statistical significance between wildtype and mutant strains, determined using Student t-test (*, P < 0.05; ***, P <0.0005).