scRNAseq reveals a distinct gene signature of MK-HSCs which is altered by Runx1 deficiency. (A) 10x Genomics scRNAseq was used to identify 4 distinct clusters in sorted LSK CD150⁺ HSCs from Runx1^–/–and Runx1^F/F group by Seurat program. (B) A quantification of the percentage of cells in the 4 clusters of Runx1^F/F and Runx1^–/–cells. (C) Heatmap of the DEGs in the 4 clusters of Runx1^F/F and Runx1^–/–cells. MK-HSCs has a distinct MK-biased signature, and both MK-HSCs and non-MK–HSCs have long-term HSCs signature. (D) Heatmap of the DEGs in the MK-HSCs of Runx1^F/F vs Runx1^–/–cells. RUNX1 deficiency alters platelet activation related gene expressions in this subset of HSCs, including Pf4, vWF, and Gp5. (E) Feature plot of marker gene Itga2b (CD41) and Gp5 (Glycoprotein V Platelet) for Runx1^–/–and Runx1^F/F groups.