Contribution of NOTCH1 dimers to gene expression in human T-cell precursors

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy characterized by an expansion of T-cell progenitors and DNA mutations that lead to an overactive NOTCH1 signaling in over 50% of T-ALL cases. Even though intracellular Notch1(ICN1) can modulate the target gene expression as a monomer, homodimerization of ICN1 is indispensable for the leukemogenesis of mouse T-cells. To define the gene expression profiling modulated by Notch1 dimers in the oncogenic transformation of human T-cell precursors, we employed three different synthetic models of T-ALL, in which normal CD34+ cells derived from human cord blood (CB) were lentivirally transduced with an activated NOTCH1 isoform, namely NOTCH1-dE alone or in a combination with known T-ALL oncogenes, such as LMO2, TAL1 and BMI1. Specifically, we performed RNA-seq on CB cells, transduced with NOTCH1-dE (wt) or NOTCH1-dE-R1984A (mut) lentiviruses alone (N only) or in combination with LMO2 (N+L) or LMO2-TAL1-BMI1 (N+LTB) constructs and subsequently expanded in vitro up to 10 days before FACS-sorting for RNA isolation and sequencing.