An oviduct-specific and enhancer-like element resides at about -3000 in the chicken ovalbumin gene.

Abstract The chicken ovalbumin(Ov) gene is one of the best models to study tissue-specific gene regulation because it is only expressed in the oviduct. In this paper, a tissue-specific element was characterized by 5′- flanking regiondeletion in combination with in vivo gene electroporation(EP). Plasmids with varying lengths of truncated Ov 5′- flanking regionfused to the Renilla luciferasereporter gene were transfected in vivo into oviduct, muscle, and pancreas. A chicken oviduct-specific and enhancer-like region (designated COSE) was implicated between −3100 and −2800. The COSE showed up- regulationof gene expressionin oviduct, but not in muscle or in pancreas. The COSE region was further characterized by gel mobility shift assays using nuclear extracts from oviduct, pancreasand liver. With the region from −2900 to −2851, designated T2, there were two distinct protein–DNA complexes: one found only in oviductextract and the other detected only in pancreasand liver. These data suggest a model where the regulation of Ov gene expression in the oviductand non- oviducttissues is exerted at least in part by the presence of protein modulators that bind to the COSE element.