Gene expression profiling of control and Meis1 deleted bone marrow

The transcription factor Meis1 is preferentially expressed in hematopoietic stem cells (HSCs) and over-expressed in certain leukemias. However, the functions of Meis1 in hematopoiesis remain largely unknown. Using inducible knock-out mice, we found that Meis1 is required for the maintenance of hematopoiesis under stress and over long term while steady-state hematopoiesis was sustained in the absence of Meis1. Bone marrow cells of Meis1 deficient mice showed reduced colony formation, contained significantly fewer numbers of long- term HSCs and these Meis1-deficient HSCs exhibited loss of quiescence. Further, we found that Meis1 deletion led to the accumulation of reactive oxygen species (ROS) in HSCs and decreased expression of genes implicated in hypoxia response. Finally, ROS scavenging by N-acetyl cysteine or stabilization of hypoxia-signaling by knockdown of the VHL protein led to reversal of the effects of Meis1-deletion. Taken together, these results demonstrate that Meis1 protects and preserves HSCs by restricting oxidative metabolism.

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Unnisa Z, Clark JP, Roychoudhury J, Thomas E, Tessarollo L, Copeland NG, Jenkins NA, Grimes HL, Kumar AR