In this series of lectures, Dr. Robert Singer explains how it is possible to follow a single mRNA molecule from its birth to its death. Singer begins by explaining that cell cultures are heterogeneous and analyzing single cells provides spatial and temporal information not available from bulk analysis. He outlines how his lab developed techniques such as fluorescence in situ hybridization (FISH) that have allowed them to measure gene expression in single cells. Using these techniques, they discovered that some RNAs localize to specific areas in the cell and RNA localization is linked to its regulation and function. For example, ß-actin mRNA localization to the leading edge of fibroblasts aids in cell motility. Singer’s lab identified “zip code” regions in mRNAs that are responsible for regulating mRNA localization.