A library of reporters of the global regulators of gene expression of Escherichia coli

The topology of the transcription factor network (TFN) of E. coli is far
from uniform, with 22 global regulator (GR) proteins controlling one-third
of all genes. So far, their production rates cannot be tracked by
comparable fluorescent proteins. We developed a library of fluorescent
reporters for 16 GRs. Each consists of a single-copy plasmid coding for
GFP fused to the full-length copy of the native promoter. We tracked their
activity in exponential and stationary growth, and under weak and strong
stresses. We show that the reporters have high sensitivity and specificity
to all stresses tested and detect single-cell variability in transcription
rates. Given the influence of GRs on the TFN, we expect that the new
library will contribute to dissecting global transcriptional
stress-response programs of E. coli. Moreover, it can be invaluable in
bio-industrial applications that tune those programs to, instead of cell
growth, favor productivity while reducing energy consumption.