TLX1 and NOTCH coregulate expression of T-cell developmental genes. (A) FACS analysis of a CD4+CD8-CD1b+ ISP-like subpopulation of TLX1+ ALL-SIL cells immediately after sorting (left) and after culture for 2 weeks (right). (B) Transient inhibition of NOTCH and downregulation of TLX1 shifts ALL-SIL populations toward a more differentiated phenotype. Flow cytometry-based comparison of TLX1+ ALL-SIL cells expressing CFP and TLX1 knockdown cells expressing shRNA93 treated by a pulse of GSI. The pulse of GSI consisted of 2 weeks treatment with 500 nM Compound E followed by culture for 1 month. (C) qRT-PCR detection of RAG1 and CD1B in the same cell lines as in B. The data shown is a representative example for CD4+CD8+ (DP) and for CD4+ (ISP-like and SP-like) populations. RNA was extracted from the cells 24 hours after sorting (P values for all comparisons are provided in Additional file 4; n = 2 biological replicates, each comprising 3 technical replicates). (D) The role of TLE corepressors in TLX1-mediated regulation of CD1b surface expression. Flow cytometric analysis of ALL-SIL expressing shRNA targeting TLX1 or panTLE. The percentage of CD1b+ populations are shown for CD4+CD8+ (green) and for CD4+ (red) populations of ALL-SIL cells.