FIG 7.

CbsR12 targets and upregulates translation of a carA-luciferase fusion construct. (A) Secondary structure of the carA 5′ UTR as predicted by Mfold. Red asterisks indicate TSSs for the shorter transcripts as determined by 5′ RACE. (Nucleotide 1 was determined to be the TSS for the full-length transcript by 5′ RACE.) Colored lines represent the start codon (green), the predicted RBS (red), and the determined CbsR12-binding sites (blue). (B) Representation of CbsR12 binding to the carA transcript as determined by IntaRNA, with the respective base numbers indicated. The top strand in the model represents the carA sequence, while the bottom strand represents the complementary CbsR12 sequence. (C) carA-luc reporter assay indicating relative luminescence units produced by pBESTluc constructs with (i) no luciferase production (frameshifted luciferase), (ii) pBESTluc vector (pBEST), (iii) pBESTluc with the carA 5′ UTR upstream of luc but lacking cbsR12 (pBEST+carA 5′ UTR), and (iv) carA 5′ UTR upstream of luc plus the cbsR12 gene driven by a Ptac promoter (pBEST+carA 5′ UTR+cbsR12). Values represent means ± the SEM from three independent determinations (*, P < 0.05 [Student t test]).