Expression profiles of GATA3, PU.1, and Bcl11b around the T lineage commitment checkpoint. (A) Schematic of early T cell development is shown with expression kinetics of the transcription factors Spi1 (PU.1), Runx1, Gata3, and Bcl11b. (B) Intracellular staining for GATA3 and PU.1 was performed using DN thymocytes from Bcl11b-YFP reporter mice, gated as in Fig. S1 A. Representative profiles of isotype control (left), GATA3 (middle), and PU.1 (right) with Bcl11b-YFP in DN1, DN2a, and DN2b are shown with the percentages of cells in each quadrant. Results are representative of three independent experiments. (C) Intracellular staining profiles of GATA3 (left) and PU.1 (right) in DN1, DN2a-YFP⁻, DN2a-YFP⁺, and DN2b are shown. The gray-filled histogram shows isotype control staining. GATA3, DN2a YFP⁺ and DN2b curves overlap; PU.1, DN1 and DN2a YFP⁻ curves overlap. Results are representative of three independent experiments.