A nuclear GFP transcriptional reporter to study endoderm and cardiac development in the mouse.

The GATA zinc-finger transcription factor GATA4 is expressed in a variety of tissues during mouse embryonic development and in adult organs. These include the primitive endoderm of the blastocyst, visceral endoderm of the early post-implantation embryo, as well as lateral plate mesoderm, developing heart, liver, lung and gonads. Here, we generate a novel targeted allele used to generate both a transcriptional reporter and a fusion protein to analyse dynamic expression domains. We demonstrate that the transcriptional reporter faithfully recapitulates known sites of mRNA expression and correlates with endogenous GATA4 protein levels. This reporter labels nuclei of expressing cells and is suitable for time-lapse imaging and single cell analyses. As such, this allele will be a useful tool for studying expression and transcriptional regulation.This article has an associated First Person interview with the first author of the paper.