Sp1 regulates FZD1 expression.

<p>Over-expression of Sp1 increases FZD1 and MMA treatment decreases both Sp1 and FZD1 expression in Saos2 cells. (A) Dose-dependent up-regulation of FZD1 protein by Sp1. Saos2 cells were infected with the indicated amounts of Ad-HA-Sp1. After 36 hours, cells were harvested for protein and Western blot analysis of both Sp1 and FZD1. (B) Densitometry analysis of the relative levels of protein expression in Fig 3A. (C) Down-regulation of FZD1 expression by Sp1 knockdown in Saos2 cell by MMA. Saos2 cells were treated with MMA at 20, 100, 200 nM for 24 hrs. Protein was harvested for Western blot with Sp1 and FZD1 specific antibodies. (D) Densitometry analysis of the relative levels of protein expression in Fig 3C. * indicates significant differences between the indicated groups (<i>P</i> < 0.05).