mRNA and Protein Co-Localization on Tissue Sections by Sequential, Colorimetric In Situ Hybridization and Immunohistochemistry

Two methods are commonly employed to characterize the spatiotemporal aspect of gene expression: 1. in situ hybridization (ISH), which localizes mRNA transcripts using a labeled nucleotide probe and 2. immunohistochemistry (IMH), which detects protein gene products by means of labeled primary or secondary antibodies. Because these methods may be, and often are, done with whole-mount specimens to obtain resolution at the cellular level, they are performed on histological sections. Generally, by using adjacent, serial sections, cellular staining patterns for messenger ribonucleic acid (mRNA) may be compared to that of the corresponding protein product. This chapter outlines a combination of the two procedures performed on the same tissue sections to provide immediate, direct visualization of the expression pattern of a particular gene at both the mRNA and protein levels.