Amylin gene expression mediated by cAMP/PKA and transcription factors HNF-1 and NFY

• Published in: Molecular and cellular endocrinology 2003-11, Vol.210 (1), p.63-75
• Main Authors: Cluck, Michael W, Murphy, Leon O, Olson, Jody, Knezetic, Joseph A, Adrian, Thomas E
• Format: Article
• Language: English
• Subjects: 1-Methyl-3-isobutylxanthine - pharmacology; Amylin; Amyloid - genetics; Amyloid - metabolism; Animals; CCAAT-Binding Factor - metabolism; Cell Line; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases - antagonists & inhibitors; Cyclic AMP-Dependent Protein Kinases - metabolism; DNA-Binding Proteins - metabolism; Gene Expression Regulation; Hepatocyte Nuclear Factor 1; Hepatocyte Nuclear Factor 1-alpha; HNF-1; Insulin - genetics; Insulin - metabolism; Islet Amyloid Polypeptide; Islets of Langerhans - cytology; Islets of Langerhans - drug effects; Islets of Langerhans - metabolism; Isoquinolines - pharmacology; mRNA; Mutagenesis, Site-Directed; NFY; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Phosphodiesterase Inhibitors - pharmacology; Promoter Regions, Genetic; Protein Binding; Rats; Sulfonamides; Transcription; Transcription Factors - metabolism
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/j.mce.2003.08.005

The regulation of amylin gene expression is not clearly understood. In this study, we used the pancreatic β cell line, INS-1, to evaluate the regulation of amylin gene expression. When INS-1 cells were cultured in media containing IBMX, the ratio of amylin secretion to insulin secretion increased by 200%. This coincided with an increase in amylin mRNA content. Moreover, there was a three to four-fold increase in amylin promoter activity which was inhibited by the specific protein kinase A (PKA) inhibitor, H89. Electrophoretic mobility shift assays (EMSA) demonstrated that IBMX induced protein–DNA binding to the FLAT and CAAT elements of the amylin promoter. Competitive EMSA experiments revealed that these proteins are likely to be HNF-1 and NFY, respectively. IBMX-induced amylin promoter activity was inhibited by mutations in the FLAT and CAAT elements. These results indicate that amylin is positively regulated by cAMP and PKA through the transcription factors HNF-1 and NFY.