Identification and validation of HOXB4 target genes. Bland-Altman plots showing comparative gene expression between (A) 12-week HOXB4-LSK cells and 12-week GFP-LSK cells, (B) 20-week HOXB4-LSKs and 20-week GFP-LSKs, (C) 12-week HOXB4-LSKs and 6-week HOXB-LSKs, and (D) 20-week HOXB4-LSKs and 6-week HOXB4-LSKs. The y-axis indicates the magnitude of change for a given probe set and the x-axis the average of the signal observed for a given probe set on the Mouse HT_MG_430_PM array. The red dots represent differentially expressed probe sets with a >0.5-log differential expression and FDR < 0.05. (E) Heatmap of the top upregulated and downregulated genes from 20-week HOXB4-LSKs compared with 20-week GFP-LSKs. Each column contains data from an independent replicate of the designated experimental group. Red represents upregulated genes, and blue boxes represent downregulated genes. (F) Quantitative RT-PCR measurement of differential gene expression for 13 HOXB4-regulated genes in CD34^−/low LSK cells harvested at 20 weeks posttransplantation. This is compared with the expression microarray results of the same genes. The fold change is indicated for HOXB4-transduced cells relative to GFP control cells.