Regulation of sipA by RyhB paralogs as determined by interaction site prediction and fluorescence assay. A Interaction site prediction between RyhB-1/RyhB-2 and sipA. The fragment containing nt 14–35 in the sipA mRNA is predicted to form base pairs with RyhB-1 and RyhB-2 (nt 46–66). B Prediction of the sipA mRNA secondary structure by RNAstructure module of CLC Main Workbench (5.5) software. The 5′ UTR of sipA that form incomplete base pairing with RyhBs are marked in red, while the bases of the coding region that form the stem-loop structure with 5′ UTR of sipA are marked in blue. C Single colonies on LB plates imaged using the natural light mode and fluorescence mode, respectively, by an inverted fluorescence microscope. D Bacterial fluorescence units when cultured in LB liquid medium. The dada were analyzed statistically using unpaired Student’s t-test. E GFP protein expression in E. coli TOP10 containing various fusion plasmids as determined by Western blotting. 1. no sRNA::5′ UTR sipA-gfp; 2. ryhB-1::5′ UTR sipA-gfp; 3. ryhB-2::5′ UTR sipA-gfp. GAPDH was used as a loading control.