Real-time RNA profiling within a single bacterium Le,Thuc T. Harlepp, Sébastien Calin Guet ; https://orcid.org/0000-0001-6220-2052 Dittmar,Kimberly Emonet,Thierry Pan,Tao Cluzel,Philippe Characterizing the dynamics of specific RNA levels requires real-time RNA profiling in a single cell. We show that the combination of a synthetic modular genetic system with fluorescence correlation spectroscopy allows us to directly measure in real time the activity of any specific promoter in prokaryotes. Using a simple inducible gene expression system, we found that induced RNA levels within a single bacterium of Escherichia coli exhibited a pulsating profile in response to a steady input of inducer. The genetic deletion of an efflux pump system, a key determinant of antibiotic resistance, altered the pulsating transcriptional dynamics and caused overexpression of induced RNA. In contrast with population measurements, real-time RNA profiling permits identifying relationships between genotypes and transcriptional dynamics that are accessible only at the level of the single cell. National Academy of Sciences 2005 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/3753 Le T, Harlepp S, Guet CC, et al. Real-time RNA profiling within a single bacterium. <i>PNAS</i>. 2005;102(26):9160-9164. doi:<a href="https://doi.org/10.1073/pnas.0503311102">10.1073/pnas.0503311102</a> info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.0503311102 info:eu-repo/semantics/closedAccess