Fig. 4. WUS expression and function is altered in zll-1 mutant embryos. (A-C) gWUS-GFP₃ expression in wild-type (WT) Arabidopsis embryo. (A) 16-cell stage showing WUS-GFP₃ (green). (B) Late heart stage embryo showing WUS-GFP₃ marking the organising centre. (C) Walking-stick stage embryo. The meristem dome is indicated with a dashed line. Inset shows endogenous WUS mRNA localisation in an embryo at the same stage. (D-F) gWUS-GFP₃ in zll-1. (D) 16-cell stage embryo. (E) Late heart stage embryo. (F) Walking-stick stage embryo showing a broad domain of gWUS-GFP₃ expression. The flat meristem dome is indicated with a dashed line. Inset shows endogenous WUS mRNA localisation at the same stage. (G) Wild-type seedling. (H) Wild-type ATRPS5A>>WUS seedling showing ectopic outgrowths on the hypocotyl (arrows) and stunted cotyledons. (I) zll-1 seedling. (J) zll-1 ATRPS5A>>WUS seedling. All seedlings shown are at 11 days post-germination. c, cotyledon; sam, shoot apical meristem; h, hypocotyl; l, leaf; ts, terminal structure. Scale bars: 10 µm in A-F; 0.5 mm in G-J.