Fig 4. SirR regulates gene expression of the stress response in S. pneumoniae.

(A) RNA-seq heatmap shows gene expression of the comparison between the ΔsirR and wt strains incubated in ABM with relative gene expression in log₂ fold change demonstrating increased expression in green and decreased expression in red. Gene expressions higher than 2-fold and p values <0.05 were considered significant. (B) Categories of SirR-regulated genes obtained from an RNAseq analysis. An RNAseq generated distribution in functional categories of genes that are regulated in the ΔsirR mutant relative to strain wt. (C) Putative SirR-regulated genes expressed in the ΔsirR mutant relative to strain wt. Gene expression determined by RNAseq was confirmed by qPCR. The ΔsirR and wt strains were grown in BHI to the mid-exponential phase in triplicate and then incubated in ABM for 1h. The fold change in gene expression was measured by RT-qPCR and calculated using the 2^–ΔΔCT method. The gyrA gene was used as internal control.