Functional characterization of a unique liver gene promoter.

Journal Article (Journal Article)

Human phenylalanine hydroxylase (PAH) is specifically expressed in the liver to convert L-phenylalanine to L-tyrosine. Deficiency of the PAH enzyme causes classic phenylketonuria, a common genetic disorder. The human PAH gene has a TATA-less promoter with multiple transcriptional initiation sites. A 9-kilobase DNA fragment 5'-flanking to the human PAH gene is sufficient to confer tissue- and developmental stage-specific expression of a reporter gene in transgenic mice. Deletion studies showed that the -121-base pair proximal promoter still retained a significant level of activity in hepatic cells. At least two protein binding sites, PAH-A and PAH-B, were identified in the proximal region of the human PAH promoter using rat liver nuclear extract. The PAH-A site covers a unique palindromic sequence, and the PAH-B site contains CCCTCCC repeats. Both elements are ubiquitous and essential regulatory elements for transcriptional activity. Nuclear protein factors that bind to the PAH-A and -B sites are detected in different cell types and are distinct from previously characterized transcription factors. No tissue-specific transcription factor binding sites have been detected within the proximal promoter region of the human PAH gene. These results suggest that the PAH gene promoter has a unique organization of regulatory elements for its tissue-specific expression in comparison with other liver gene promoters.

Full Text

Duke Authors

Cited Authors

  • Wang, Y; Hahn, TM; Tsai, SY; Woo, SL

Published Date

  • March 25, 1994

Published In

Volume / Issue

  • 269 / 12

Start / End Page

  • 9137 - 9146

PubMed ID

  • 8132651

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States