(a) Molecular profiles of pre-selection DP and SP8 thymocytes from CytoQuad mice. Expression of mRNA encoding Runx3d, Runx1 and Runx2 were compared in pre-selection DP and SP8 thymocytes from B6 and CytoQuad mice (left). Histograms of CD103 expression on DP and SP8 thymocytes from CytoQuad mice are shown (right). Data are technical triplicates from 1-6 pooled mice and one of two experiments is shown. (b) Impact of TGF-β on SP8 thymocyte generation. Profiles of TCRβhi thymocytes from γccKO FTOCs cultured with TGF-β or medium are shown, and numbers in boxes within the profiles indicate frequency of SP8 cells among TCRβhi thymocytes (top left). Numbers of SP8 cells generated in γccKO FTOCs cultured with and without TGF-β were compared (top right). DP and SP8 thymocytes from γccKO FTOCs cultured with TGF-β were profiled as in (a), with quantitative PCR of mRNA encoding Runx3d, Runx1, and Runx2 shown (bottom left) and surface CD103 histograms displayed (bottom right). Data are from 8-12 individual lobes combined from 2 experiments. (c) Comparison of CD103 expression on SP8 thymocytes from various mice. Data are from 4 mice combined from 2 experiments. Mean and s.e.m. are shown. ****P < 0.0001.