FIGURE 3.

β-Catenin directly regulates GATA3 expression to modulate adipocyte differentiation. A and B, β-catenin level was determined to check the β-catenin knockdown effect in 3T3-L1 preadipocytes by RT-PCR (A) and Western blotting (B). C, GATA3 protein level was determined in 3T3-L1 preadipocytes without or with β-catenin knockdown. D, GATA3 protein level was determined in 3T3-L1 preadipocytes without or with LiCl treatment (25 mm) for 48 h. E, GATA3 protein level was determined in 3T3-L1 preadipocytes without or with AICAR (0.5 mm) treatment for 48 h together without or with β-catenin knockdown (KD). F, the overexpression of GATA3 was detected by Western blotting. G, 3T3-L1 preadipocytes overexpressing GATA3 or an empty vector control (Ctrl) were induced to differentiate in the absence or presence of β-catenin knockdown, as indicated. The extent of differentiation at 9 days post-induction was assessed by Oil Red O staining, and lipid accumulation was quantified. Scale bars, 50 μm. H and I, the expression of PPARγ and C/EBPα was determined in the cells with the same treatment as described in G by RT-PCR (H) and Western blotting (I). J, ChIP assay of GATA3 binding at the PPARγ2 promoter (pro) under the specified conditions for 48 h. A neighbor region of the PPARγ2 gene without transcripts (Non-pro) was used as a negative binding control region, and nonspecific IgG was used as a negative control for chromatin pulldown. One-way ANOVA was used in G, and other statistics were performed using Student's t test; bar graphs are mean ± S.E. In vitro data are the means of three independent experiments. *, p < 0.05; **, p < 0.01.