FIG 6.

Reduced TCR expression in Erk3^−/− DP thymocytes. (A) Cell surface expression of TCRβ in Erk3^−/− DP thymocytes from E18.5 embryos. The representative overlay shows TCRβ cell surface expression by Erk3^+/+ (thin line) and Erk3^−/− (thick line) DP thymocytes. (B) Quantification of the percentages (top) and numbers (bottom) of TCR^lo, TCR^int, and TCR^hi DP thymocytes. The bar represents the mean value, and each dot corresponds to one mouse. (C) Real-time PCR analysis of Tcra gene expression on sorted DP thymocytes from Erk3^+/+ and Erk3^−/− mice. (D) Overlay histograms show phospho-H2AX staining in Erk3^+/+ (thin line) or Erk3^−/− (thick line) DP (TCR^lo, TCR^int, and TCR^hi) thymocytes from E18.5 embryos. Numbers on the graph indicate the means ± SEM of the percentages of phospho-H2AX-positive cells. (E) The numbers of phospho-H2AX-positive cells in total DP thymocytes are shown for Erk3^+/+ and Erk3^−/− newborn mice. (F) Quantification of DNA DSBs at different Jα gene segments. Genomic DNA isolated from DP thymocytes of Erk3^+/+ and Erk3^−/− mice was subjected to ligation-mediated qPCR. (G) mRNA quantification of Rag1 and Rag2 on sorted DP thymocytes from Erk3^+/+ and Erk3^−/− mice. Data are representative of at least 3 independent experiments. *, P < 0.05; ***, P < 0.01; two-tailed Student's t test.