APLNR expression during mesoderm induction. Flow cytometric analysis of (A) E-CADHERIN and GFP and (B) PDGFRα and GFP expression in MIXL1^GFP/w EBs differentiated in medium supplemented with mesodermal-inducing growth factors (BVS). Regions used to sort cells into fractions for further analysis are shown. Comparison of transcriptional profiles of sorted (C) E-CAD⁺GFP⁻ (E⁺G⁻) versus E-CAD⁻GFP⁺ (E⁻G⁺) cells and (D) GFP⁻PDGFRα⁻ (G⁻P⁻) versus GFP^brPDGFRα⁺ (G^brP⁺) cell fractions. Colored dots indicate probes with expression differing by ≥ 5.0-fold from the mean. Several key genes present in each cell population are highlighted. (E) Venn diagram displaying the overlap of genes up-regulated in E⁻G⁺ and G^brP⁺ sorted populations. (F) Relative signal intensities from 4 independent microarray analyses indicating the enrichment of APLNR expression in E⁻G⁺, E⁺G⁺, G⁺P⁺, and G^hiP⁺ nascent mesodermal populations from BVS-, BVSA-, and BVSW-treated EBs (growth factor concentrations provided in “Cell culture and differentiation” and supplemental Figure 1). Samples differentiated under neurectodermal conditions in FGF2 (FGF) served as a negative control for mesoderm differentiation. uns indicates unsorted.