Open AccessThe restricted promoter activity of the liver transcription factor hepatocyte nuclear factor 3 beta involves a cell-specific factor and positive autoactivation.
Author(s) -
L Pani,
X B Quian,
D Clevidence,
Robert H. Costa
Publication year - 1992
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.12.2.552
Subject(s) - transcription factor , biology , hepatocyte nuclear factors , hepatocyte nuclear factor 4 , promoter , microbiology and biotechnology , dna binding protein , binding site , nuclear protein , beta (programming language) , dna binding site , sp1 transcription factor , transcription (linguistics) , gene expression , gene , genetics , nuclear receptor , computer science , programming language , linguistics , philosophy
The transcription factor hepatocyte nuclear factor 3 (HNF-3) is involved in the coordinate expression of several liver genes. HNF-3 DNA binding activity is composed of three different liver proteins which recognize the same DNA site. The HNF-3 proteins (designated alpha, beta, and gamma) possess homology in the DNA binding domain and in several additional regions. To understand the cell-type-specific expression of HNF-3 beta, we have defined the regulatory sequences that elicit hepatoma-specific expression. Promoter activity requires -134 bp of HNF-3 beta proximal sequences and binds four nuclear proteins, including two ubiquitous factors. One of these promoter sites interacts with a novel cell-specific factor, LF-H3 beta, whose binding activity correlates with the HNF-3 beta tissue expression pattern. Furthermore, there is a binding site for the HNF-3 protein within its own promoter, suggesting that an autoactivation mechanism is involved in the establishment of HNF-3 beta expression. We propose that both the LF-H3 beta and HNF-3 sites play an important role in the cell-type-specific expression of the HNF-3 beta transcription factor.