REGULATED EXPRESSION OF GATA-6 TRANSCRIPTION FACTOR IN GASTRIC ENDOCRINE-CELLS

Background & Aims: GATA transcription factors may regulate gene expres sion in developing tissues, including gut epithelium. In the stomach, their expression has been linked to regulation of proton pump genes. H owever, GATA consensus sequences also occur in the promoter of the his tidine decarboxylase gene, located in enterochrommafin-like cells. The aim of this study was to determine if GATA factors are located in gas tric endocrine cells and to examine their expression during developmen t and in response to changes in the gastric luminal environment. Metho ds: Polymerase chain reaction cloning, Northern blot, and gel shift as says were used to examine GATA expression in gastric endocrine cells; changes in GATA messenger RNA during develop ment and in response to f asting, feeding, and gastric achlorhydria were determined by Northern blot. Results: GATA-6 was expressed strongly in rodent gastric endocri ne 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 b ound specifically to GATA consensus sequences in the human histidine d ecarboxylase promoter. GATA messenger RNA abundance was upregulated du ring terminal differentiation of the rat stomach and on feeding after a fast. Conclusions: The GATA-6 transcription factor is expressed in g astric endocrine cells and is a potential regulator of gastric differe ntiation and of genes involved in the response to feeding.