A comprehensive, non-invasive visualization of primordial germ cell development in mice by the Prdm1-mVenus and Dppa3-ECFP double transgenic reporter

Abstract

The ability to monitor the development of a given cell lineage in a non-invasive manner by fluorescent markers bothin vivoandin vitroprovides a great advantage for the analysis of the lineage of interest. To date, a number of transgenic or knock-in mouse strains, in which developing germ cells are marked with fluorescent reporters, have been generated. We here describe a novel double transgenic reporter mouse strain that expresses membrane-targeted Venus (mVenus), a brighter variant of yellow fluorescent protein (YFP), under the control ofPrdm1(Blimp1) regulatory elements and enhanced cyan fluorescent protein (ECFP) under the control ofDppa3(Stella/Pgc7). The double transgenic strain unambiguously markedPrdm1expression in the lineage-restricted precursors of primordial germ cells (PGCs) in the proximal epiblast at embryonic day (E) 6.25 and specifically illuminatedPrdm1- andDppa3-positive migrating PGCs after E8.5. The double transgenic reporter also precisely recapitulated dynamic embryonic expression ofPrdm1outside the germ cell lineage. Moreover, we derived ES cells that bore both transgenes. These cells made a robust contribution both to the germ and somatic cell lineages in chimeras with accuratePrdm1-mVenus andDppa3-ECFP expression. The transgenic strain and the ES cells will serve as valuable experimental materials not only for analyzing the origin and properties of the germ cell lineagein vivo, but also for establishing a culture system to efficiently induce proper germ cells with temporally coordinatedPrdm1andDppa3expressionin vitro.