HNF-1 regulates the promoter activity of the HP-27 gene.

The hibernation-specific HP-27 gene is expressed specifically in the liver of the chipmunk, a hibernating species of the squirrel family, and exists as a pseudogene in the tree squirrel, a nonhibernating species. In the promoter region, the chipmunk gene has a potential HNF-1 binding site, and the tree squirrel gene has two base substitutions in the corresponding sequence. In this paper, we investigated the role of HNF-1 in the HP-27 gene promoter activity.

Comparative study of HP-27 gene promoter activities between the chipmunk and tree squirrel.

The chipmunk hibernation-specific protein HP-27 is a component of the 140-kDa complex that decreases in the blood during hibernation. Although the HP-27 gene is detected in both the chipmunk, a hibernating species of the squirrel family, and the tree squirrel, a nonhibernating species, it is expressed only in the chipmunk, in a liver-specific manner. To understand the difference in HP-27 gene expression between the chipmunk and tree squirrel, we isolated chipmunk and tree squirrel HP-27 genomic clones, and compared their promoter activities.