Cholecystokinin gene transcription: promoter elements, transcription factors and signaling pathways

Cholecystokinin (CCK) is a neuropeptide expressed in the small intestine and in the central and peripheral nervous system. CCK gene expression is both spatially and temporally regulated. In neurons CCK production is increased by growth factors, cyclic adenosine 3', 5'-monophosphate (cAMP), dopamine, estrogen, and injury situations, while intestinal CCK expression is mainly regulated by food intake. The function of the proximal CCK promoter has been examined by transfection of human CCK-CAT reporter constructs in cultured cells, DNase I footprinting and gel shift assays. These studies have led to the identification of regulatory elements and transcription factors important for basal and stimulated gene expression and depicted the signaling pathways involved in growth factor and cAMP induced CCK transcription. The review outlines the current knowledge of the regulation of CCK transcription and describes the role of putative transcription factors in tissue-specific CCK gene expression.