
<ArticleTitle>Molecular cloning and characterization of human <prot>nonsteroidal anti-inflammatory drug-activated gene</prot> promoter. Basal transcription is mediated by <prot>Sp1</prot> and <prot>Sp3</prot>.</ArticleTitle>
<AbstractText><prot>Nonsteroidal anti-inflammatory drug-activated gene</prot> (<prot>NAG-1</prot>) is known to be associated with anti-tumorigenic activity and belongs to the <prot>transforming growth factor-beta</prot> superfamily. In the present study, we cloned the promoter region (-3500 to +41) and investigated the transcriptional regulatory mechanisms of the basal expression of the human <prot>NAG-1</prot> gene. Several potential transcription factor-binding sites in this region were identified. Based on the results from clones of nested deletions, the construct between -133 and +41 base pairs contains three <prot>Sp1</prot>-binding sites (<prot>Sp1</prot>-A, <prot>Sp1</prot>-B, and <prot>Sp1</prot>-C), which confer basal transcription specific activity of <prot>NAG-1</prot> expression. When the <prot>Sp1</prot>-C site was mutated (GG to TT), a 60-80% decrease in promoter activity was observed in HCT-116 cells. Gel shift, co-transfection, and chromatin immunoprecipitation assays showed that the Sp transcription factors bind to the <prot>Sp1</prot>-binding sites and transactivate <prot>NAG-1</prot> expression. In addition, <prot>chicken ovalbumin</prot> <prot>upstream promoter-<prot>transcription factor 1</prot></prot> can interact with the C-terminal region of <prot>Sp1</prot> and <prot>Sp3</prot> proteins and induce <prot>NAG-1</prot> promoter activity through <prot>Sp1</prot> and <prot>Sp3</prot> transcription factors. These results identify the critical regulatory regions for the human <prot>NAG-1</prot> basal promoter. Furthermore, the results suggest that the level of expression of the NAG-1 gene will depend on the availability of Sp proteins and on co-factors such as <prot>chicken ovalbumin</prot><prot> upstream promoter-<prot>transcription factor 1</prot></prot>.</AbstractText>
