Transcription factors enriched in the various EPCs. (A) FACS data of late EPC surface antigens at different passages. (B) A principal component analysis (PCA) plot showing distinct differentiation pathways between embryonic and somatic endothelial differentiation (using genes differentially expressed between ESC and matured endothelial cells; 6446 probe sets, q < 10-5). ESC and differentiated precursors from the GEO data sets GSE19735 and GSE21668. Each spot represents a single array sample. (C & E) Nuclear proteins of early (C) and late (E) EPCs (defined by the “Cellular Component” ontology in the GO database) with transcription factor activities (defined by the GO “Molecular Function” ontology). (D & F) Validation of array data by RT-qPCR. (G) Expression patterns of late EPC transcription factors during in vitro cultivation.