Orphan nuclear receptor small heterodimer partner represses hepatocyte nuclear factor 3/Foxa transactivation via inhibition of its DNA binding

Joon-Young Kim; Han-Jong Kim; Kyung Tae Kim; Yun-Yong Park; Hyun-A Seong; Ki Cheol Park; In-Kyu Lee; Hyunjung Ha; Minho Shong; Sang Chul Park; Hueng-Sik Choi

doi:10.1210/me.2004-0211

Orphan nuclear receptor small heterodimer partner represses hepatocyte nuclear factor 3/Foxa transactivation via inhibition of its DNA binding

Mol Endocrinol. 2004 Dec;18(12):2880-94. doi: 10.1210/me.2004-0211. Epub 2004 Sep 9.

Authors

Joon-Young Kim¹, Han-Jong Kim, Kyung Tae Kim, Yun-Yong Park, Hyun-A Seong, Ki Cheol Park, In-Kyu Lee, Hyunjung Ha, Minho Shong, Sang Chul Park, Hueng-Sik Choi

Affiliation

¹ Hormone Research Center, Chonnam National University, Gwangju 500-757, Korea.

PMID: 15358835
DOI: 10.1210/me.2004-0211

Abstract

Small heterodimer partner (SHP; NR0B2) is an atypical orphan nuclear receptor and acts as a coregulator of various nuclear receptors. Herein, we examined a novel cross talk between SHP and a forkhead transcription factor HNF3 (hepatocyte nuclear factor 3/Foxa. Transient transfection assay demonstrated that SHP inhibited the transcriptional activity of all three isoforms of HNF3, HNF3alpha, beta, and gamma. In vivo and in vitro protein interaction studies showed that SHP physically interacted with HNF3. Adenovirus-mediated overexpression of SHP significantly decreased the mRNA levels of glucose-6-phosphase (G6Pase), cholesterol 7-alpha-hydroxylase (CYP7A1), and phosphoenolpyruvate carboxykinase (PEPCK) in HepG2 cells and rat primary hepatocytes. Moreover, the mRNA level of G6Pase was notably increased by down-regulation of SHP with small interfering RNA. Interestingly, HNF3 transactivity was still repressed by SHPDelta128-139 that fails to repress nuclear receptors. Mapping of interaction domain revealed that SHP interacted with forkhead DNA binding domain of HNF3alpha. Gel mobility shift and chromatin immunoprecipitation assays demonstrated that SHP inhibits DNA binding of HNF3. These results suggest that SHP is involved in the regulation of G6Pase, CYP7A1, and PEPCK gene expression via novel mechanism of inhibition of HNF3 activity and expand the role of SHP as a coregulator of other family of transcription factors in addition to nuclear receptors.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Binding, Competitive
Cell Line
Cell Nucleus / chemistry
Cholesterol 7-alpha-Hydroxylase / genetics
Chromatin Immunoprecipitation
DNA-Binding Proteins / antagonists & inhibitors*
DNA-Binding Proteins / genetics
DNA-Binding Proteins / metabolism
Down-Regulation / genetics
Electrophoretic Mobility Shift Assay
Glucose-6-Phosphatase / genetics
Helix-Loop-Helix Motifs / genetics
Hepatocyte Nuclear Factor 3-alpha
Hepatocyte Nuclear Factor 3-beta
Hepatocyte Nuclear Factor 3-gamma
Humans
Nuclear Proteins / antagonists & inhibitors*
Nuclear Proteins / genetics
Nuclear Proteins / metabolism
Phosphoenolpyruvate Carboxykinase (GTP) / genetics
Promoter Regions, Genetic / genetics
Protein Interaction Mapping
RNA, Small Interfering / genetics
Receptors, Cytoplasmic and Nuclear / analysis
Receptors, Cytoplasmic and Nuclear / metabolism
Receptors, Cytoplasmic and Nuclear / physiology*
Repressor Proteins / metabolism
Repressor Proteins / physiology*
Transcription Factors / antagonists & inhibitors*
Transcription Factors / genetics
Transcription Factors / metabolism
Transcriptional Activation / genetics

Substances

DNA-Binding Proteins
FOXA1 protein, human
FOXA2 protein, human
FOXA3 protein, human
Hepatocyte Nuclear Factor 3-alpha
Nuclear Proteins
RNA, Small Interfering
Receptors, Cytoplasmic and Nuclear
Repressor Proteins
Transcription Factors
nuclear receptor subfamily 0, group B, member 2
Hepatocyte Nuclear Factor 3-gamma
Hepatocyte Nuclear Factor 3-beta
Cholesterol 7-alpha-Hydroxylase
Glucose-6-Phosphatase
Phosphoenolpyruvate Carboxykinase (GTP)