Gut specific expression using mammalian promoters in transgenic Xenopuslaevis

Abstract

The recent development of transgenic methods for the frog Xenopuslaevis provides the opportunity to study later developmental events, such as organogenesis, at the molecular level. Our studies have focused on the development of the tadpole gut, where tissue specific promoters have yet to be identified. We have used mammalian promoters, for the genes elastase, pancreaticduodenalhomeobox-1, transthyretin, and intestinalfattyacidbindingprotein to drive green fluorescent protein expression in live tadpoles. All of these were shown to drive appropriate tissue specific expression, suggesting that the molecular mechanisms organising the gut are similar in amphibians and mammals. Furthermore, expression from the elastase promoter is initiated in the pancreatic buds before morphological definition becomes possible, making it a powerful tool for the study of pancreatic determination.