Base Pairing Interaction between 5′- and 3′-UTRs Controls icaR mRNA Translation in Staphylococcus aureus
(A) β-galatosidase assays measuring icaA promoter activity in the wild type and Δ3′-UTR strains grown in TSB-gluc at 37°C until exponential phase (OD600 nm = 0.8). Each bar represents the average of three independent assays. (B) Consequences of icaR mRNA 3′-UTR deletion on PIA-PNAG exopolysaccharide synthesis and biofilm production of S. aureus 15981 and 132 strains. (C) In vivo effects of either the mutation or the substitution of the 894UCCCCUG900 motif on PIA-PNAG synthesis. Quantification of PIA-PNAG exopolysaccharide biosynthesis by dot-blot. Serial dilutions (1/5) of the samples were spotted onto nitrocellulose membranes and PIA-PNAG production was detected with specific anti-PIA-PNAG antibodies. (D) Biofilm development of the wild type and Δ3′-UTR strains grown in microfermentors under continuous flow for 8 h at 37°C. The glass slides where bacteria form the biofilm are shown. (E) Biofilm development of the S. aureus 15981 with the pCN40, pIcaRm_WT and pIcaRm_SUBST plasmids grown in microfermentors under continuous flow for 8 h at 37°C.