FIGURE 5.

Effects of Wnt signaling pathway on GnT-III expression. A, subconfluent β-catenin knockdown cells were incubated with or without Wnt3a (300 ng/ml), BIO (2 μm), SB415286 (50 μm), or quercetin (300 μm) for 48 h and then harvested for assay of GnT-III activities. Equal amounts of cell lysate protein (10 μg) were used as the enzymatic source for GnT-III. S, substrate; P, product. B, quantitative data for the relative activities of GnT-III from three independent experiments. Error bars, S.D. *, p < 0.01; **, p < 0.0001 compared with cells in the presence of buffer without these reagents. The subconfluent cells were cultured for 72 h in the absence or presence of Wnt3a (C), BIO (D), or quercetin (E) and then harvested and lysed for immunoblotting. Equal amounts of protein (20 μg) were separated on 7.5% SDS-PAGE under reducing conditions, and the membranes were probed with E4-PHA (top), and reprobed with anti-α-tubulin (bottom), which was used as a loading control. Control, without retroviral infection; Mock, retroviral infection with a random sequence. The asterisks indicate nonspecific staining of E4-PHA because those bands did not disappear after treatment with 100 mm acetic acid.