Scl or Fli rescues EC and HPC development in Etv2-null cells. (A) Expression of Scl or Fli1 alone could restore EC and HPC development in Etv2-null cells. Scl or Fli1 was introduced into Etv2-null ESCs using a Tet-inducible system. Cells differentiated on OP9 were analyzed by flow cytometry after 10 days. CD41⁺CD45⁺or VECAD⁺ cells developed but with lower efficiency compared with Etv2-rescued cells (except CD41⁺ cells in Scl rescue). (B) VECAD⁺ cells were sorted from Scl- or Fli1-rescued Etv2^−/− differentiated cells and recultured on OP9 for an additional 8 days in the presence of HPC growth factors. This reculture generated a significant number of VECAD⁺ or CD45⁺ cells from both Scl- (a) and Fli1 (b)–rescued Etv2-null cells.