Etv2 transcriptionally regulates Yes1 and promotes cell proliferation during embryogenesis

Etv2, an Ets-transcription factor, governs the specification of the earliest hemato-endothelial progenitors during embryogenesis. While the transcriptional networks duringhemato-endothelial development have been well described, the mechanistic details areincompletely defined. In the present study, we described a new role for Etv2 as aregulator of cellular proliferation via Yes1 in mesodermal lineages. Analysis of an Etv2-ChIPseq dataset revealed significant enrichment of Etv2 peaks in the upstream regionsof cell cycle regulatory genes relative to non-cell cycle genes. Our bulk-RNAseq analysisusing the doxycycline-inducible Etv2 ES/EB system showed increased levels of cell cyclegenes including E2f4, Gadd45g and Ccne1 as early as 6h following Etv2 induction.Further, EdU-incorporation studies demonstrated that the induction of Etv2 resulted in a~2.5-fold increase in cellular proliferation, supporting a proliferative role for Etv2 duringdifferentiation. Next, we identified Yes1 as the top-ranked candidate that was expressedin Etv2-EYFP + cells at E7.75 and E8.25 using single cell RNA-seq analysis. Doxycycline-mediated induction of Etv2 led to an increase in Yes1 transcripts in a dose-dependentfashion. In contrast, the level of Yes1 was reduced in Etv2 null embryoid bodies. Usingbioinformatics algorithms, biochemical, and molecular biology techniques, we show thatEtv2 binds to the promoter region of Yes1 and functions as a direct upstream regulator ofYes1 during embryogenesis. These studies enhance our understanding of themechanisms whereby Etv2 governs mesodermal fate decisions early duringembryogenesis.