Transcription complexes that contain Ldb1 and Lmo2 bind to the promoters of key dysregulated genes in Lmo2-tg thymocytes and human T-ALL cells. (A) Binding of Ldb1 in mouse hematopoietic progenitor cells at the promoters of Lyl1, Hhex, and Nfe2 (genes that are upregulated in Lmo2-tg thymocytes). Shown are mm9 UCSC Genome Browser shots of ChIP-seq (IgG and Ldb1) performed on lin^neg bone marrow cells enriched for hematopoietic progenitors.¹⁷  (B) Ldb1 binding sites identified by ChIP-exo sequencing of anti-Ldb1 ChIP samples from LOUCY human T-ALL cells. (C-D) ChIP-quantitative PCR (ChIP-qPCR) analysis of Ldb1/Lmo2 complex binding sites at the Lyl1, Hhex, and Nfe2 genes (sites are shown in A). Samples for ChIP-qPCR were lineage-depleted (DN) thymocytes pooled from 3 Ldb1^fl/fl;Lmo2-tg (Cre⁻) or 3 Il-7rα-Cre;Ldb1^fl/fl;Lmo2-tg (Cre⁺) mice. ChIP was performed with anti-Ldb1 (C) or anti-Lmo2 (D). Bar height is the mean, and error bars show standard deviation. There was no significant difference in ChIP-qPCR results with Cre⁻ and Cre⁺ samples using control primers and probes located near but outside the binding sites shown in A (data not shown).