Fig. 1.

Immunohistochemical characterization of cholecystokinin (CCK) cells from the proximal small intestine of a mouse in which enhanced green fluorescent protein (GFP) is expressed downstream from the mouse CCK promoter (CCK-GFP) mouse. Intestinal CCK cell expressing endogenous GFP (left), stained with CCK-specific antisera (center), and merged image showing colocalization of GFP and CCK (right). Microscopic images are from a section of the proximal small intestine of a CCK-GFP mouse. Sections were stained with DAPI to identify cell nuclei (blue). Images were captured with a ×63 objective and ×1.4 Zeiss LSM software zoom. Scale bar = 5 μm.