A ratiometric dual-color luciferase reporter for fast characterization of transcriptional regulatory elements

Abstract

Plant synthetic biology requires precise characterization of genetic elements to construct complex genetic circuits that can improve plant traits or confer them new characteristics. Transcriptional reporter assays are essential to quantify the effect of gene expression regulator elements. Therefore, transcriptional reporter systems are a key tool in understanding control of gene expression in biology. In this work we construct and characterize a dual-color luciferase ratiometric reporter system that possesses several advantages over currently used reporters. It is ratiometric, reducing variability and increasing consistency between experiments; it is fast, as both reporters can be measured at the same time in a single reaction, and it is cheaper to perform than current dual-luciferase reporter assays. We have validated our system quantifying the transcriptional capability of a panel of promoters and terminators commonly used in synthetic biology with a broad range of expression magnitudes, and in a biologically relevant system, nitrate response.