Comparison of the evolution of the erythroblast proteome during human and murine erythropoiesis. (A) A comparison of the overall protein content in primary human and murine erythroblasts. The total protein content was calculated by summing the amounts of each protein quantified by MS analysis. (B) PCA of the protein expression in murine and human erythroblasts (log₂ of the copy number per cell values). (C) Hierarchical clustering analysis of the protein expression (in log₂) during murine and human erythropoiesis. (D) Comparison of the expression pattern and the absolute protein expression in murine and human erythropoiesis. Each point corresponds to one of the proteins quantified in both human and murine erythropoiesis. The Pearson correlation coefficient of the expression pattern (x-axis) was calculated after z-score transformation of the expression values. The ratio of the median expression value in mice to the median expression value in human erythropoiesis is indicated (y-axis). Right: the expression of selected proteins is indicated (protein copy number in linear scale). (E) Expression of the main transcription factors during human and murine erythropoiesis. (F) Absolute expression of Gata1 and relative expression of Gfi1B, Tal1, and Klf1 compared with Gata1 during human and murine erythropoiesis. (G) Mean expression (left) of 318 mRNAs with an opposite pattern of expression during human and murine erythropoiesis.¹⁶  A total of 140 proteins encoded by these mRNAs were quantified in both human and murine primary cells and in MEDEP cells (right). See supplemental Figure 7 for a comprehensive comparison of the protein expression in the different clusters reported in An et al.¹⁶