Comparison of the P<i>cag</i>-<i>lux</i> and P<i>cag</i>-5′UTR-<i>lux</i> reporter signals.

<p><b>A</b>. Schematic representation of the P<i>cag</i>-<i>lux</i> and P<i>cag</i>-5′UTR-<i>lux</i> fusion constructs, obtained transforming the G27<i>lux</i> acceptor strain with the PVCC vector. The promoter sequences with or without the 5′untranslated regions (5′UTRs) carried by the pVCC vector are inserted upstream the <i>luxCDABE</i> operon by double homologous recombination and selected by <i>cat</i> chloramphenicol resistance. <b>B</b>. Luminescence signals from three independent experiments were normalized according to the optical density of the cultures and the means values were reported in the graph, with P<i>cag</i>-<i>lux</i> signals on the X-axis and P<i>cag</i>-5′UTR-<i>lux</i> signals on the Y-axis. Error bars indicate the standard deviation. A dashed line was added to the graph, corresponding to the 1∶1 ratio of the two signals. Grey dots: <i>cag</i> promoters with 1∶1 signal ratio; black dots: <i>cag</i> promoters with altered P<i>cag</i>-<i>lux/</i>P<i>cag</i>-5′UTR-<i>lux</i> signal ratio.