Figure 4. The structure of the 5′-UTR can influence translational efficiency and translational regulation.

Specific putative structure elements were stabilized and destabilized in a native 5′-UTR (compare Figure 3). Translational efficiencies of the mutated versions and the wild type were determined by using the reporter gene system. (A) The transcript fusions are shown schematically. The DHFR enzymatic activities, the dhfr transcript levels and the translational efficiencies of exponential and stationary growth phases are tabulated. Three biological replicates were performed and average values with standard deviations (in parenthesis) were calculated. (B) The translational efficiencies after normalization to the control transcript without UTRs (No. 1) are shown.