Review Article | 24 July 2020

Gene expression is typically measured at the level of either mRNAs or proteins. In this Review, Buccitelli and Selbach discuss how large-scale comparative studies are characterizing the degree to which mRNA and protein levels correlate. They discuss technical and biological reasons why mRNA and protein levels may be particularly concordant or disconnected, as well as the different biological information provided by these non-redundant readouts of gene expression.