Tg(Neurog3-lacZ)1Ggr

A DNA fragment containing 6,696 bp of 5' genomic and untranslated region plus 176 bp of coding sequence from the neurogenenin 3 (Neurog3) locus drives expression of E. coli beta-galactosidase, with an N-terminal nuclear localization signal (NLS), from an internal ribosome entry site (IRES). Expression of the lacZ transcript faithfully recapitulates that of the endogenous Neurog3 gene in the gut, where it is confined in the adult to dividing progenitor cells of the intestinal crypts, and in the pancreas. Beta-galactosidase activity is detectable in enteroendocrine progenitor cells in the embryonic pancreas and along the length of the proximal-to-distal axis of the developing intestinal tract. In adult mice, activity is present in neurogenin 3-positive pancreatic islet cells and in both crypts and villi of the intestinal epithelium; in villi, this activity is presumed due to persistence of the enzyme in differentiated progeny of the transcript-expressing crypt cells and is limited to cells of the enteroendocrine lineage. (J:80672)