The kinase DYRK2 is repressed by KLF4 in leukemia stem/progenitor cells. (A) Gene expression heat map showing the most deregulated genes comparing GFP⁺ LSK cells purified from Klf4^fl/fl and Klf4^Δ/Δ CML mice. (B) Gene ontology analysis of deregulated cellular pathways using Ingenuity Pathway Analysis. (C) Immunoblot analysis of DYRK2 protein expression in purified GFP⁺ LSK cells (leukemia stem/progenitor cells) from the bone marrow of CML mice and LSK cells (hematopoietic stem/progenitor cells). Densitometry values were used to estimate the fold increase compared with wild-type using values normalized to actin. (D) Analysis of KLF4 occupancy at the DYRK2 promoter in lineage-negative bone marrow cells from CML mice by ChIP-PCR analysis. Genomic DNA was immunoprecipitated with anti-KLF4 antibody (KLF4 Ab) or IgG control and amplified with primers spanning the DYRK2 promoter, upstream, and exon sequences. (E) Promoter assay using a KLF4 expression plasmid and Dyrk2-luciferase reporter construct in the 293T cell line. (F) Analysis of DYRK2 messenger RNA levels in CD34⁺ cells from healthy individuals and CML patients in the chronic phase using a published data set (GSE4170). (G) DYRK2 qPCR in CD34⁺ CD38⁻ (stem) and CD34⁺ CD38⁺ (progenitor) cells purified from CML patients and healthy donors. (H) Immunoblot analysis of DYRK2 expression in a panel of lymphoid and myeloid leukemia cell lines. *P < .05, **P < .01, ***P < .001, 2-tailed Student t test (D-E), Mann-Whitney U test (F-G). n.d., not detected.