Regulated expression of GATA-6 transcription factor in gastric endocrine cells

Background & Aims: GATA transcription factors may regulate gene expression in developing tissues, including gut epithelium. In the stomach, their expression has been linked to regulation of proton pump genes. However, GATA consensus sequences also occur in the promoter of the histidine decarboxylase gene, located in enterochrommafin-like cells. The aim of this study was to determine if GATA factors are located in gastric endocrine cells and to examine their expression during development and in response to changes in the gastric luminal environment. Methods: Polymerase chain reaction cloning, Northern blot, and gel shift assays were used to examine GATA expression in gastric endocrine cells; changes in GATA messenger RNA during develop ment and in response to fasting, feeding, and gastric achlorhydria were determined by Northern blot. Results: GATA-6 was expressed strongly in rodent gastric endocrine cell fractions, in a human ECL cell tumor, and in an endocrine cell line (STC-1) derived from gut epithelium; proteins from STC-1 cells bound specifically to GATA consensus sequences in the human histidine decarboxylase promoter. GATA messenger RNA abundance was upregulated during terminal differentiation of the rat stomach and on feeding after a fast. Conclusions: The GATA-6 transcription factor is expressed in gastric endocrine cells and is a potential regulator of gastric differentiation and of genes involved in the response to feeding.