Hepatocyte nuclear factor 3/fork head or "winged helix" proteins: a family of transcription factors of diverse biologic function.

Transcription of hepatocyte-specific genes requires the interaction of their regulatory regions with several nuclear factors. Among them is the hepatocyte nuclear factor 3 (HNF3) family, composed of the HNF3 alpha, HNF3 beta, and HNF3 gamma proteins, which are expressed in the liver and have very similar fork head DNA binding domains. The regulatory regions of numerous hepatocyte-specific genes contain HNF3 binding sites. We examined the role of HNF3 proteins in the liver-specific phenotype by turning off the HNF3 activity in well-differentiated mhAT3F hepatoma cells. Cells were stably transfected with a vector allowing the synthesis of an HNF3 beta fragment consisting of the fork head DNA binding domain without the transactivating amino- and carboxy-terminal domains. The truncated protein was located in the nuclei of cultured hepatoma cells and competed with endogenous HNF3 proteins for binding to cognate DNA sites. Overproduction of this truncated protein, lacking any transactivating activity, induced a dramatic decrease in the expression of liver-specific genes, including those for albumin, transthyretin, transferrin, phosphoenolpyruvate carboxykinase, and aldolase B, whereas the expression of the L-type pyruvate kinase gene, containing no HNF3 binding sites, was unaltered. Neither were the concentrations of various liver-specific transcription factors (HNF3, HNF1, HNF4, and C/EBP alpha) affected. In partial revertants, with a lower ratio of truncated to full-length endogenous HNF3 proteins, previously extinguished genes were re-expressed. Thus, the transactivating domains of HNF3 proteins are needed for the proper expression of a set of liver-specific genes but not for expression of the genes encoding transcription factors found in differentiated hepatocytes.

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Hepatocyte nuclear factor 3/fork head homolog 11 is expressed in proliferating epithelial and mesenchymal cells of embryonic and adult tissues.

Molecular and Cellular Biology ◽

10.1128/mcb.17.3.1626 ◽

1997 ◽

Vol 17 (3) ◽

pp. 1626-1641 ◽

Cited By ~ 252

Author(s):

H Ye ◽

T F Kelly ◽

U Samadani ◽

L Lim ◽

S Rubio ◽

...

Keyword(s):

Oxidative Stress ◽

Transcription Factor ◽

Epithelial Cells ◽

Cell Line ◽

Mrna Levels ◽

Nuclear Factor ◽

Hepatocyte Nuclear Factor ◽

Winged Helix ◽

Fork Head ◽

Ht 29

The hepatocyte nuclear factor 3alpha (HNF-3alpha) and 3beta proteins have homology in the winged helix/fork head DNA binding domain and regulate cell-specific transcription in hepatocytes and in respiratory and intestinal epithelia. In this study, we describe two novel isoforms of the winged helix transcription factor family, HNF-3/fork head homolog 11A (HFH-11A) and HFH-11B, isolated from the human colon carcinoma HT-29 cell line. We show that these isoforms arise via differential splicing and are expressed in a number of epithelial cell lines derived from tumors (HT-29, Caco-2, HepG2, HeLa, A549, and H441). We demonstrate that differentiation of Caco-2 cells toward the enterocyte lineage results in decreased HFH-11 expression and reciprocal increases in HNF-3alpha and HNF-3beta mRNA levels. In situ hybridization of 16 day postcoitus mouse embryos demonstrates that HFH-11 expression is found in the mesenchymal and epithelial cells of the liver, lung, intestine, renal cortex, and urinary tract. Although HFH-11 exhibits a wide cellular expression pattern in the embryo, its adult expression pattern is restricted to epithelial cells of Lieberkühn's crypts of the intestine, the spermatocytes and spermatids of the testis, and the thymus and colon. HFH-11 expression is absent in adult hepatocytes, but its expression is reactivated in proliferating hepatocytes at 4, 24, and 48 h after partial hepatectomy. Consistent with these findings, we demonstrate that HFH-11 mRNA levels are stimulated by intratracheal administration of keratinocyte growth factor in adult lung and its expression in an adult endothelial cell line is reactivated in response to oxidative stress. These experiments show that the HFH-11 transcription factor is expressed in embryonic mesenchymal and epithelial cells and its expression is reactivated in these adult cell types by proliferative signals or oxidative stress.

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Hepatocyte nuclear factor 3 beta contains two transcriptional activation domains, one of which is novel and conserved with the Drosophila fork head protein

Molecular and Cellular Biology ◽

10.1128/mcb.12.9.3723-3732.1992 ◽

1992 ◽

Vol 12 (9) ◽

pp. 3723-3732

Author(s):

L Pani ◽

D G Overdier ◽

A Porcella ◽

X Qian ◽

E Lai ◽

...

Keyword(s):

Amino Acids ◽

Transcription Factors ◽

Transcriptional Activation ◽

Carboxyl Terminus ◽

Nuclear Factor ◽

Hepatocyte Nuclear Factor ◽

Amino Terminal ◽

Fork Head ◽

Fourth Segment ◽

Region Ii

The hepatocyte nuclear factor 3 (HNF-3) gene family is composed of three proteins (alpha, beta, and gamma) that are transcription factors involved in the coordinate expression of several liver genes. All three proteins share strong homology in their DNA binding domains (region I) and are able to recognize the same DNA sequence. They also possess two similar stretches of amino acids at the carboxyl terminus (regions II and III) and a fourth segment of homology at the amino terminus (region IV). Furthermore, the HNF-3 proteins demonstrate homology with the Drosophila homeotic gene fork head in regions I, II, and III, suggesting that HNF-3 may be its mammalian homolog. In order to define HNF-3 beta protein domains involved in transcriptional activation, we have used a reporter gene, whose transcription is dependent on HNF-3 binding, for hepatoma cell cotransfection assays with expression vectors that produced different truncated HNF-3 beta proteins. A position-independent activation domain which contained conserved regions II and III was identified at the carboxyl terminus of the HNF-3 beta protein (amino acids 361 to 458). Moreover, site-directed mutations that altered the sequences within regions II and III demonstrated their importance to transactivation. The region II-III domain does not possess amino acid sequences in common with other transcription factors and may define a novel activation motif. HNF-3 beta amino-terminal sequences defined by conserved region IV also contributed to transactivation, but region IV activity required the participation of the region II-III domain. Region IV is abundant in serine amino acids and contains two putative casein kinase I phosphorylation sites, a feature similar to protein motifs described for the transcription factors Pit-1/GHF-1 and HNF-1.

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Hepatocyte nuclear factor 3 beta contains two transcriptional activation domains, one of which is novel and conserved with the Drosophila fork head protein.

Molecular and Cellular Biology ◽

10.1128/mcb.12.9.3723 ◽

1992 ◽

Vol 12 (9) ◽

pp. 3723-3732 ◽

Cited By ~ 112

Author(s):

L Pani ◽

D G Overdier ◽

A Porcella ◽

X Qian ◽

E Lai ◽

...

Keyword(s):

Amino Acids ◽

Transcription Factors ◽

Transcriptional Activation ◽

Carboxyl Terminus ◽

Nuclear Factor ◽

Hepatocyte Nuclear Factor ◽

Amino Terminal ◽

Fork Head ◽

Fourth Segment ◽

Region Ii

The hepatocyte nuclear factor 3 (HNF-3) gene family is composed of three proteins (alpha, beta, and gamma) that are transcription factors involved in the coordinate expression of several liver genes. All three proteins share strong homology in their DNA binding domains (region I) and are able to recognize the same DNA sequence. They also possess two similar stretches of amino acids at the carboxyl terminus (regions II and III) and a fourth segment of homology at the amino terminus (region IV). Furthermore, the HNF-3 proteins demonstrate homology with the Drosophila homeotic gene fork head in regions I, II, and III, suggesting that HNF-3 may be its mammalian homolog. In order to define HNF-3 beta protein domains involved in transcriptional activation, we have used a reporter gene, whose transcription is dependent on HNF-3 binding, for hepatoma cell cotransfection assays with expression vectors that produced different truncated HNF-3 beta proteins. A position-independent activation domain which contained conserved regions II and III was identified at the carboxyl terminus of the HNF-3 beta protein (amino acids 361 to 458). Moreover, site-directed mutations that altered the sequences within regions II and III demonstrated their importance to transactivation. The region II-III domain does not possess amino acid sequences in common with other transcription factors and may define a novel activation motif. HNF-3 beta amino-terminal sequences defined by conserved region IV also contributed to transactivation, but region IV activity required the participation of the region II-III domain. Region IV is abundant in serine amino acids and contains two putative casein kinase I phosphorylation sites, a feature similar to protein motifs described for the transcription factors Pit-1/GHF-1 and HNF-1.

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Hepatocyte Nuclear Factor 4 alpha 2 Messenger RNA Reprograms Liver‐Enriched Transcription Factors and Functional Proteins in End‐Stage Cirrhotic Human Hepatocytes

Hepatology Communications ◽

10.1002/hep4.1763 ◽

2021 ◽

Author(s):

Edgar N. Tafaleng ◽

Amitava Mukherjee ◽

Aaron Bell ◽

Kazutoyo Morita ◽

Jorge Guzman‐Lepe ◽

...

Keyword(s):

Transcription Factors ◽

Messenger Rna ◽

Human Hepatocytes ◽

Nuclear Factor ◽

Hepatocyte Nuclear Factor ◽

Hepatocyte Nuclear Factor 4 ◽

End Stage

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Myocyte nuclear factor, a novel winged-helix transcription factor under both developmental and neural regulation in striated myocytes

Molecular and Cellular Biology ◽

10.1128/mcb.14.7.4596-4605.1994 ◽

1994 ◽

Vol 14 (7) ◽

pp. 4596-4605

Author(s):

R Bassel-Duby ◽

M D Hernandez ◽

Q Yang ◽

J M Rochelle ◽

M F Seldin ◽

...

Keyword(s):

Transcription Factors ◽

Transcriptional Activation ◽

Myogenic Differentiation ◽

Specific Binding ◽

Motor Nerve ◽

Sequence Motif ◽

Nuclear Factor ◽

Winged Helix ◽

Amino Terminal ◽

Myocyte Nuclear Factor

A sequence motif (CCAC box) within an upstream enhancer region of the human myoglobin gene is essential for transcriptional activity in both cardiac and skeletal muscle. A cDNA clone, myocyte nuclear factor (MNF), was isolated from a murine expression library on the basis of sequence-specific binding to the myoglobin CCAC box motif and was found to encode a novel member of the winged-helix or HNF-3/fork head family of transcription factors. Probes based on this sequence identify two mRNA species that are upregulated during myocyte differentiation, and antibodies raised against recombinant MNF identify proteins of approximately 90, 68, and 65 kDa whose expression is regulated following differentiation of myogenic cells in culture. In addition, the 90-kDa form of MNF is phosphorylated and is upregulated in intact muscles subjected to chronic motor nerve stimulation, a potent stimulus to myoglobin gene regulation. Amino acid residues 280 to 389 of MNF demonstrate 35 to 89% sequence identity to the winged-helix domain from other known members of this family, but MNF is otherwise divergent. A proline-rich amino-terminal region (residues 1 to 206) of MNF functions as a transcriptional activation domain. These studies provide the first evidence that members of the winged-helix family of transcription factors have a role in myogenic differentiation and in remodeling processes of adult muscles that occur in response to physiological stimuli.

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