Proteomic analyses of primitive erythroid precursors at E10.5 and E12.5 of gestation. (A) Erythroid precursors were isolated from the bloodstream of murine embryos at E10.5 and E12.5 of development, predominantly consisting of BasoEs and OrthoEs, respectively, and analyzed by LC-MS/MS proteomics. (B-D) Significant changes between the 2 groups (n = 5) were observed by unsupervised principal component analysis (PCA) (B), partial least square discriminant analysis (variable importance in projection [VIP] plots for PC1 are shown) (C), and hierarchical clustering analysis of the top 1000 significantly different proteins (t test) (D). (E) Highlight of the top 75 significantly different entries from this analysis is provided in the heat map.