Homeobox protein Meis1 (MEIS1)

Acts as a transcriptional regulator of PAX6.

Acts as a transcriptional activator of PF4 in complex with PBX1 or PBX2.

Required for hematopoiesis, megakaryocyte lineage development and vascular patterning. May serve as a cofactor for HOXA7 and HOXA9 in the induction of myeloid leukemias.