Assessing translational efficiency by a reporter protein co-expressed in a cell-free synthesis system.

We demonstrate the use of a cell-free protein synthesis system as a convenient tool for assessing the relative translational efficiencies of genes. When sfGFP was used as a common reporter gene and co-expressed with a series of target genes, the intensities of sfGFP fluorescence from the co-expression reactions were highly correlated with the individual expression levels of the co-expressed genes. The relative translational efficiencies of genes estimated by this method were reproducible when the same genes were expressed in transformed Escherichia coli, suggesting that this method could be used as a universal tool for prognostic assessment of translational efficiency.