(A) ISPs from BRD4 cKO and WT thymi were cultured overnight, and the extent of their proliferation was quantified as cell recovery (percent of input) after theovernight culture; data are the mean ± SEM of four independent experiments. *p < 0.05; t test.
(B) Maturation of ISP into DP (culture panel), relative to the input (input panels) of ISPs from WT (top) and cKO (bottom), was assessed by flow-cytometricmeasurement of CD4 and CD8 surface marker expression. The histogram (right) represents the mean ± SEM of four independent cultures of Brd4 cKO ISPs and four WT ISPs. **p < 0.005; t test.
(C) FACS of the input ISPs remaining after culture (cult.ISP_37˚C) and DP appearing after culture (cult.DP_37˚C) (from B) assessing their size by forward scatter (top) and TCRβ surface expression (bottom). WT, gray; Brd4 cKO, black; shaded peak, WT ISP input. The data are representative of four independent experiments.
(D) The heatmap was plotted based on 3,194 genes that are differentially expressed between DP_WT after overnight culture (cult.DP_WT) and input ISP_WT(Input_WT). Input ISPs from Brd4 cKO mice (Input_cKO), remaining cKO ISPs (cult.ISP_cKO), and cKO DPs (cult.DP_cKO) after overnight culture.
(E) PCA representation of the WT and cKO input ISP and thymocyte populations after overnight culture.
See also Figure S5.