MEK1 ablation increases the frequency of metabolically active HSCs generated in culture. Related to Fig. 1. (A and B) Representative clustering analysis of Sca1, MitoTracker, tetramethylrhodamine ethyl ester (TMRE) (A) and for Sca1, ROS, LysoTracker (B) in 1_div cells from CTRL (left panel) and cKO (right panel) HSC cultures. HSCs were isolated from mice recovering from one 5-FU injection. The pie charts depict the frequency of cells in the corresponding cluster in three independent experiments. The mean (± SD) percentage of cells in each cluster is indicated. For A and B, P < 0.0001 according to Fisher’s exact test comparing CTRL and cKO black and yellow clusters.