Human insulin gene enhancer‐binding proteins in pancreatic α and β cell lines

Abstract
Electrophoretic mobility shift assays were performed using oligonucleotides corresponding to known protein binding sites within the human insulin gene enhancer and nuclear extracts from mouse pancreatic α and β cell lines. The results demonstrate that a previously described factor, IUF-1, binds to three sites at −82 (the CT1 box), −215 (the CT2 box), and −319 (the CT3 box) in the human insulin gene enhancer. IUF-1 was present only in β but not in α cells, while all other DNA-binding proteins were present in both cell lines. IUF-1 may therefore be an important determinant of insulin gene β cell-specific expression.