Analysis of RNA localization and metabolism in single live bacterial cells: achievements and challenges

Studies of gene expression at the single cell level in live bacterial cells represent a new and fertile area of research providing real-time, spatially specified information that cannot be obtained by techniques relying on large cell populations. Before recently, most single-cell studies have been concerned with gene expression at the protein level and explored the spatiotemporal localization and dynamics of different bacterial proteins. However, to fully understand the complex process of gene expression, it is necessary to visualize and quantify RNA molecules in the cellular environment. The first studies analysing the kinetics of RNA transcription and the distribution of RNA in single bacterial cells in real time have recently been reported. Here, I discuss the methods allowing RNA detection in living bacterial cells, the results on RNA kinetics and RNA localization, and the challenges for future research in this area.