Stat3 Upregulates Leucine-Rich Repeat-Containing G Protein-Coupled Receptor 4 Expression in Osteosarcoma Cells
Figure 5
Stat3 is a direct transcriptional activator of LGR4. (a) The human LGR4 promoter constructs containing a potential Stat3 binding motif (−556 to −549). (b) The transcriptional activity of the LGR4 promoter. MG63 cells were cotransfected with the indicated plasmids for 36 h, and the luciferase activity was measured. The full-length LGR4 promoter (−1000 to +110, WT-luc) was upregulated by constitutively activated Stat3, whereas the point mutant promoter (Mut-luc) abolished the Stat3-mediated transcriptional activity. (c) The truncated LGR4 promoter (−520 to +110) was unregulated by constitutively activated Stat3. (d) ChIP assays of Stat3 and its binding motif. Two antibodies (anti-IgG and -Stat3) were used in the ChIP assays using MG63 cells. Cells were incubated with vehicle control (PBS) or IL-6 (10 ng/mL) for 4 hr and then subjected to ChIP analysis. The results were quantified by real-time PCR. .
