The transgene places human cytomegalovirus (CMV VHL/E strain; human herpesvirus 5 (HHV-5)) gene US28 under control of the mouse villin 1 promoter. Three mouse lines were established; L18, L19 and L36. This line, L38, has intermediate expression in jejunum, ileum and colon epithelium: lower than L19, higher than L18. (J:166917)