Gli2ΔN2 influences Erk activation and thymocyte selection. Top panels: Gli2ΔN2 reduces negative selection in male HY-TCR Tg mice; middle panels: enhanced maturation of CD4+ T cells in female Shh+/− HY-TCR Tg mice; bottom histograms: Gli2ΔN2 Tg thymocytes show reduced activation of the MAPK Erk. See the complete figures in the article beginning on page3757.