twd40-2-3 is a knockdown allele that exhibits dwarf phenotypes and shows a genetic interaction with ap2m-1. (A and B) The length of etiolated seedlings and light-grown seedling roots was measured. (Scale bars, 10 mm.) Error bars are SEM. ***P < 0.0001 (10 ≤ n ≤ 13 for each genotype). (C and D) Col-0, ap2m-1, twd40-2-3, and ap2m-1 twd40-2-3 plants are shown at 3 and 6 wk old. Thirty-three percent of ap2m-1 twd40-2-3 mutants died at 3 wk. [Scale bars, 1 cm (C) and 5 cm (D).] (E) Western blot analysis of TWD40-2 expression in total protein extracts from Col-0, ap2m-1, twd40-2-3, ap2m-1 twd40-2-3, AP2M-YFP ap2m-1, and GFP-TWD40-2 twd40-2-3 seedlings. TWD40-2 protein levels are reduced in seedlings harboring twd40-2-3. GFP-TWD40-2 twd40-2-3 shows both knocked-down endogenous TWD40-2 and mobility-shifted GFP-TWD40-2. The loading control is a Coomassie gel.