The cell cycle protein SMC4 is a downstream target of MEIS1 in NPM1c AML. (A) Smc4 mRNA expression in NPM1^+/− plus Meis1, Hoxa9 plus Meis1, and AML1-ETO9A leukemic mice; values are shown as normalized RNA-seq counts. (B) Western blot analysis on protein extracts from NM1, H9M1 murine ex vivo leukemic cells, and human AML cell lines OCI-AML3 and OCI-AML2 probed with antibody against SMC4 and LAMIN-B as endogenous control. (C) SMC4 mRNA expression in NPM1c vs NPM1^WT AML patients in total human AML and de novo CN-AML patient cohorts from the Vizome data set; values are shown as normalized RNA-seq counts.²⁶ (D) Spearman correlation of SMC4 and MEIS1 expression in NPM1c AML patients (r = 0.55, P < .0001). (E) Smc4 mRNA expression in NM1 cells transduced with scrambled control or shRNA against Meis1 (n = 3); values are shown as fold change to housekeeping gene control, Actb. (F) CUT&RUN of MEIS1 in H9M1 and NM1 cells analyzed for enrichment of Smc4 promoter (n = 3); values are shown as percentage Smc4 enrichment in input control. ∗P < .05; ∗∗P < .001; ∗∗∗P < .0001. mRNA, messenger RNA. Actb, Actin Beta; n, number of experimental replicates.