Figure 5.

HOXB4 Does Not Re-specify Endothelial Cells to a Hematopoietic Fate

(A) iRunx ESCs expressing tamoxifen-inducible HOXB4 (tdTomato-2A-HOXB4^ERT) were differentiated as EBs for 4 days, dissociated, and single FLK-1⁺PDGFRα⁻ cells deposited and co-cultured with OP9 cells in 96-well plates. After a further 4 days, CD31⁺ tdTomato/HOXB4⁺ colonies were counted and qualified either as "endothelial colony" or "HE colony."

(B) Typical colony morphologies. Scale bars, 100 μm.

(C) Quantification of endothelial and HE colonies formed by single deposited cells +/− HOXB4 induction. –Tam, without HOXB4^ERT induction; +Tam, permanent induction of HOXB4^ERT. +Tam post sort, induction after single-cell deposition. The p values as calculated by Student's t test, paired and two-sided, with a significance level defined as 0.05, are indicated above. Forms and colors indicate endothelial and HE colonies grown on the same 96-well plate.