Whole-Mount In Situ Hybridization in Post-Implantation Staged Mouse Embryos.

Understanding RNA expression in space and time is a key initial step in dissecting gene function. The ability to visualize gene expression in whole-tissue or whole-specimen preparations, called in situ hybridization (ISH), was first developed 50 years ago. Two decades later, these protocols were adapted to establish robust methods for whole-mount ISH to murine embryos. The precise protocols vary somewhat between early-gestation and mid-gestation mouse embryos; the protocol presented here is optimal for use with post-implantation stage mouse embryos (stages 5.5-9.5 dpc). Routine uses of whole-mount ISH include documenting the wild-type expression pattern of individual genes and comparison of the expression pattern of signature genes (i.e., those that identify particular cells and tissues within an embryo) between wild-type and mutant embryos as part of a phenotyping experiment. This technique remains a mainstay of developmental biology studies and complements the massively parallel assessment of gene expression from dissociated tissues and cells via RNA-sequencing techniques. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Dissection of post-implantation (5.5-9.5 dpc) murine embryos Basic Protocol 2: Whole-mount in situ hybridization in post-implantation embryos Basic Protocol 3: Visualization of post-WMISH embryos Support Protocol 1: Creation of siliconized glass pipettes Support Protocol 2: Creation of embryo powder.