To examine the development of the AVE we monitored the expression of Cer1, Otx2, Hesx1, Lefty1 and Hex1 in E6.5 Bptf mutant embryos. Otx2 expression is required for the migration of the DVE to establish the AVE. We observed lower expression of Otx2 in the epiblast of Bptf mutant embryos relative to there wild type controls (Figure S11A). As expected we did not observe expression of AVE markers Cer1, Hesx1, Lefty1 and Hex1 in Bptf mutant embryos (Figure S11A). Combined with our analysis of E5.5 embryos our results strongly suggest that Bptf is required for the speciation of the DVE and the AVE.
