Psip1 knockout gene expression signature overlaps with that of MLL-FP target genes. (A) Heat map of RNA-seq data showing the top differentially expressed genes in Psip^Fl/Fl and Psip^Vav/Vav cells harvested after 1 round in the CFU assay. GSEA showing that Psip1-regulated genes are enriched for genes with promoter regions bound by (B) MLL complex and (C) MLL-ENL fusion. (D) Quantitative ChIP assay for Psip^Fl/Fl and Psip^Vav/Vav cells using Mll antibody. The promoter regions amplified by qPCR are indicated below the respective panels. (E) GSEA showing the correlation between the principal signature in the Psip^Vav/Vav RNA-seq samples and genes downregulated in MOLM-14 cells (AML) upon knockdown of Hoxa9. (F) CFU assay per 10⁴ cells harvested from Psip^Fl/Fl and Psip^Vav/Vav mice. Cells were transduced with pMSCV-HoxA9-pgk-neo or mock vector and plated for colony formation. Error bars indicate standard deviations of triplicate measurements. Differences were determined using Student t test; *P < .05.