Endogenous Cdx gene expression in differentiating EBs. (A) A schematic representation of the questions under study: can Cdx genes affect either the specification of hematopoietic progenitors (ie, induction of Cdx gene expression during EB differentiation) and/or the expansion and differentiation of hematopoietic progenitors (ie, induction after plating purified progenitors in OP9 and m3434 assays)? (B) Quantitative RT-PCR analysis of endogenous Cdx1, Cdx2, and Cdx4 gene expression in differentiating AinV15 EBs from day 0 through day 8. Expression is presented relative to expression level of each gene in undifferentiated ESC, after normalization to the housekeeping gene β-actin. Shown is a representative example of several independent experiments in multiple distinct ESC lines (AinV15 and CCE).