TY - JOUR AB - Fluorescence correlation spectroscopy (FCS) has permitted the characterization of high concentrations of noncoding RNAs in a single living bacterium. Here, we extend the use of FCS to low concentrations of coding RNAs in single living cells. We genetically fuse a red fluorescent protein (RFP) gene and two binding sites for an RNA-binding protein, whose translated product is the RFP protein alone. Using this construct, we determine in single cells both the absolute [mRNA] concentration and the associated [RFP] expressed from an inducible plasmid. We find that the FCS method allows us to reliably monitor in real-time [mRNA] down to similar to 40 nM (i.e. approximately two transcripts per volume of detection). To validate these measurements, we show that [mRNA] is proportional to the associated expression of the RFP protein. This FCS-based technique establishes a framework for minimally invasive measurements of mRNA concentration in individual living bacteria. AU - Calin Guet AU - Bruneaux,Luke AU - Min,Taejin L AU - Siegal-Gaskins,Dan AU - Figueroa,Israel AU - Emonet,Thierry AU - Cluzel,Philippe ID - 3754 IS - 12 JF - Nucleic Acids Research TI - Minimally invasive determination of mRNA concentration in single living bacteria VL - 36 ER -