Figure 7. SIRT1 regulates KISS1 expression through deacetylation of transcription factor CREB.

A. Gene expression profile array analysis in SW620 cells. Three-dimension (3D) profile of the expression values for mRNA of siRNA-SIRT1 cells versus siRNA-NC cells. B. Upregulation of KISS1 protein was detected when either knockdown of SIRT1 or overexpression of CREB by Western blot. C. ChIP assays for CREB and its binding motif. Antibodies anti-IgG and anti-CREB were used in the ChIP assays. QRT-PCR was performed to quantify the binding activity. D. KISS1 promoter constructs containing a potential CREB binding motif (−191 to −184 bp and −1961 to −1954 bp). The transcriptional activity of the KISS1 promoter was greatly increased after co-expression of CREB and KISS1 reporter in wild type. E. Endogenous SIRT1 immunoprecipitates with CREB. Proteins immunoprecipitated with rabbit IgG was used as control. F. Downregulation of SIRT1 increases the immunoprecipitated CREB levels detected using anti-acetyl lysine antibody. G. Western blot showing that SIRT1 overexpression suppresses forskolin-induced CREB-Ser¹³³ phosphorylation level. H. SIRT1 siRNA increases CRE transcriptional activity. Results are expressed as Luc/Renilla ratios. **P<0.01.