Fig. 3. Mapping of the LFY interaction domain. (A) Diagram of the mutated and truncated forms of LFY. Gray boxes indicate the conserved domains at the N terminus and C terminus. Either D139 or S140 were mutated to alanine and used for yeast two-hybrid assays. Four different truncated versions of LFY, LFYN1 (amino acids 1-141), LFYC1 (amino acids 142-420), LFYN2 (amino acids 1-375) and LFYC2 (amino acids 376-420) are shown. (B) Yeast two-hybrid assays testing the interaction between various LFY truncations/mutants and FUFO. Quantitative measurements of β-GAL activities (average of five independent assays) are indicated. LFYN2 fails to interact with FUFO, while LFYC1 retains the interaction. Neither of the mutant forms D139 nor S140 affected the interaction with FUFO. Bars represent mean±s.e.m. for the five replicates. (C) GST pull-down assays performed with bacterially expressed GST fusion proteins and inflorescence protein extracts from 35S::UFO-Myc plants. Top panel, western blot probed with anti-Myc antibody. Bottom panel, Coomassie Blue stained gel showing GST fusion proteins used in the assays. LFYN2 does not pull down UFO as efficiently as does full-length LFY from plant extracts.