Fig. 6. Partial rescue of the loss of Nurr1⁺ and Th⁺ cells in Ngn2 mutant mice by endogenous or overexpressed Mash1. (A) At E11.5, Mash1 is transiently downregulated in zone 1 of Ngn2^–/– mice (arrow), but has partially recovered by E13.5. (B) Substitution of Ngn2 expression by Mash1 (Ngn2^{KIMash1/KIMash1}, abbreviated to Ngn2^M/M) did not rescue the reduction in number of Th⁺ cells observed in Ngn2 mutants at E11.5. (C,E-G) However, Mash1 overexpression partially rescues the loss of Th⁺ DA neurons at E14.5. (D,H-J) The greater loss of Nurr1⁺ cells in Ngn2;Mash1 double mutants than in Ngn2 single mutants indicates that endogenous Mash1 partially rescues the loss of Nurr1⁺ precursors at E14.5 (B-D, n=3-6; ^***P<0.001, one-way ANOVA, with Bonferroni's correction for multiple comparisons). Scale bar: 100 µm in A; 20 µm in E-J.