GLUCOSE STIMULATES THE ACTIVATION DOMAIN POTENTIAL OF THE PDX-1 HOMEODOMAIN TRANSCRIPTION FACTOR

Glucose-stimulated expression of the insulin gene in beta cells is med iated by the PDX-1 transcription factor. In this report, we show that stimulation results from effects on activation and DNA-binding potenti al. Thus, glucose specifically stimulated expression in MIN6 beta cell s from chimeras of PDX-1 and the GAL4 DNA-binding domain which spanned the N-terminal PDX-1 activation domain located between amino acids 1 to 79, GAL4:PDX activity mas induced over physiological glucose concen trations and mas also regulated by effecters of this response. The lev el of endogenous PDX-1 binding and phosphorylation were also induced u nder these conditions. We discuss hom changes in PDX-1 phosphorylation mag influence activity in glucose-treated beta cells. (C) 1998 Federa tion of European Biochemical Societies.