Metabolic regulation of LT-HSCs by Meis1. (A) RT-PCR histogram demonstrates the significant down-regulation of Hif-1α and Hif-2α (EPAS1), but not Hif-3α after Meis1 deletion in LT-HSCs (n = 3). (B) Measurement of oxygen consumption rate for 6 hours demonstrates significantly higher aerobic phosphorylation in Meis1^−/− LT-HSCs compared with Meis1^+/+ LT-HSCs (n = 3). (C) Quantification of labeled lactated in glycolytic flux assay demonstrates that Meis1^−/− LT-HSCs are less glycolytic (n = 3). (D) Measurement of reactive oxygen species (ROS) in LT-HSCs as determined by quantification of the percentage of DCFDA⁺ LT-HSCs in Meis1^+/+ and Meis1^−/− mice (n = 3). (E) RT-PCR of p16 and p19 demonstrates association of higher level of ROS with up-regulation of p16 and p19 in Meis1^−/− LT-HSCs (n = 3). (F) Figure shows conserved consensus Meis1 motifs found on Hif-2α (EPAS1) gene. Note the duplex Meis1-binding motifs found next to each other and conserved till Opossum. (G) Luciferase reporter assays demonstrate dose-dependent transcriptional activation of Hif-2α by Meis1 (n = 3). (H) Real-time PCR with primers flanking the consensus Meis1-binding sequence after ChIP assay demonstrating in vivo binding of Meis1 to Hif-2α promoter (n = 3); *P < .05, **P < .01.