Src-Yap1 signaling axis controls the trophectoderm and epiblast lineage differentiation in mouse embryonic stem cells

The tyrosine kinase Src is highly expressed in embryonic stem cells (ESCs) and ESC-differentiated cells, however, its functional role remains obscured. Here, we constitutivelyexpressed Src in mouse ESCs and found these cells retained comparable levels of the core pluripotent factors, such as Oct4 and Sox2, while promoted the expression of epiblast lineage markers and restrained trophoblast lineage markers compared to the control ESCs. Knockdown of Src in mouse ESCs showed the opposite effect. Directly differentiation of these ESCs to epiblast and trophoblast lineage cells revealed that Src activation dramatically accelerated the production of epiblast-like cells and inhibited the induction of trophoblast-like cells in vitro. Mechanistically, we found Src activation enhanced the Yap1-Tead interaction and their transcriptional output in mouse ESCs through specially upregulating Yap1 tyrosine phosphorylation. Subsequently, we found that overexpression of Yap1 in mouse ESCs phenocopied the differentiation patterns of Src overexpressing cells in vitro. Moreover, inhibition of Src kinase activity by Dasatinib or Yap1/Tead-mediated transcription with Verteporfin reversed the differentiation patterns of Src overexpressing ESCs. Taken together, our results unravel a novel Src-Yap1 regulatory axis during mouse ESC differentiation to trophectoderm and epiblast lineage cells in vitro.