scholarly journals Synergistic activation of the Atlantic salmon hepatocyte nuclear factor (HNF) 1 promoter by the orphan nuclear receptors HNF4 and chicken ovalbumin upstream promoter transcription factor I (COUP-TFI)

2000 ◽  
Vol 352 (2) ◽  
pp. 557-564 ◽  
Author(s):  
Alan MCNAIR ◽  
Silvia CEREGHINI ◽  
Heike BRAND ◽  
Terry SMITH ◽  
Christelle BREILLAT ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Atlantic Salmon ◽  
Nuclear Receptors ◽  
Nuclear Hormone Receptor ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Orphan Nuclear Receptors ◽  
Synergistic Activation ◽  
Upstream Promoter ◽  
Chicken Ovalbumin

Hepatocyte nuclear factor 1 (HNF1) is a liver-enriched transcription factor that plays an important role in transcriptional networks involved in liver function. The promoters of mammalian HNF1 genes contains a single binding site for another liver-enriched transcription factor, the nuclear hormone receptor HNF4. A transcriptional hierarchy involving HNF4-mediated activation of the HNF1 promoter has been proposed to be of crucial importance in maintaining the differentiated hepatocyte phenotype. Here we present evidence that the Atlantic salmon HNF1 promoter contains three nuclear-hormone-receptor-binding sequences. Gel-shift assays showed that these motifs are recognized with different affinities by HNF4 and the orphan nuclear receptors chicken ovalbumin upstream promoter transcription factors COUP-TFI and COUP-TFII. In hepatoma cells, the site showing highest affinity for HNF4 appears to be crucial for promoter activity. Transfection experiments in non-hepatic cells indicated that the salmon HNF1 promoter was activated by both HNF4 and COUP-TFs. We also identified a promoter fragment encompassing the two more distal nuclear-hormone-binding sites that was activated by HNF4, unaffected by COUP-TF and showed a strong synergistic activation by HNF4/COUP-TF. Results are presented detailing these interactions in relation to the salmon HNF1 promoter architecture.

scholarly journals Chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and hepatocyte nuclear factor 4gamma (HNF-4gamma) and HNF-4alpha regulate the bovine growth hormone receptor 1A promoter through a common DNA element

2004 ◽  
Vol 32 (3) ◽  
pp. 947-961 ◽  
Author(s):  
Q Xu ◽  
N Walther ◽  
H Jiang
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Growth Hormone Receptor ◽  
Bovine Liver ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Hybrid Analysis ◽  
Factor Ii ◽  
Upstream Promoter ◽  
Chicken Ovalbumin

The growth hormone receptor (GHR) 1A promoter is responsible for transcription of the liver-specific GHR mRNA variant 1A in several mammalian species. We previously found that the region between nucleotide -218 and nucleotide -151 (relative to the major transcription start site) of the bovine GHR 1A promoter contained a binding site between -196 and -178 for the liver-enriched transcription factor hepatocyte nuclear factor 4alpha (HNF-4alpha) and that the same region might also interact with additional transcription factors in the liver. Using the -218/-151 region as bait to screen a bovine liver cDNA library in a yeast one-hybrid analysis, we identified chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) and HNF-4gamma, as well as HNF-4alpha, as binding proteins to the -218/-151 region. These binding proteins were also identified in a second yeast one-hybrid analysis using the -196/-178 region as bait, suggesting that COUP-TFII, HNF-4gamma and HNF-4alpha all bind to the -196/-178 region. Electrophoretic mobility shift assays confirmed the ability of these three transcription factors in bovine liver nuclear extracts to interact with the -196/-178 region. These interactions also appeared to exist in vivo, as the GHR 1A promoter containing the -196/-178 region could be recovered by immunoprecipitation of the bovine liver chromatin with antibody against COUP-TFII, HNF-4gamma or HNF-4alpha. In co-transfection analyses, each of these three transcription factors could activate GHR 1A promoter and the activation was dependent on the -196/-178 region. These results together identify COUP-TFII, HNF-4gamma and HNF-4alpha as transcription factors regulating GHR 1A promoter activity through binding to a common DNA element.

scholarly journals Pseudopregnancy induces the expression of hepatocyte nuclear factor-1β and its target gene aminopeptidase N in rabbit endometrium via the epithelial promoter

1995 ◽  
Vol 312 (1) ◽  
pp. 31-37 ◽  
Author(s):  
J Olsen ◽  
I Classen-Linke ◽  
H Sjöström ◽  
O Norén
Keyword(s):  
Transcription Factor ◽  
Binding Proteins ◽  
Experimental Manipulation ◽  
Nuclear Hormone Receptor ◽  
Aminopeptidase N ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Parallel Increase ◽  
Nuclear Factor 1

The rabbit endometrium is an excellent model system allowing experimental manipulation of aminopeptidase N (APN) mRNA expression in vivo. By RNase mapping and sequencing of cloned PCR-amplified primer-extended RNA, it was demonstrated that endometrial APN expression is directed by the epithelial APN promoter and is increased in human-choriogonadotropin-induced pseudopregnancy. Cloning and sequencing of the rabbit APN epithelial promoter revealed conservation of the upstream footprint (UF), hepatocyte nuclear factor-1 (HNF1) and Sp1 elements known to be present in the pig and human promoters as well. The pseudopregnancy-induced APN expression was found to be accompanied by a parallel increase in the level of the transcription factor HNF1 beta, whereas a much smaller increase in Sp1 and UF-binding proteins was observed. This indicates that HNF1 beta acts as a switch triggering the pregnancy-induced APN expression. The sequence of the UF element suggests members of the nuclear hormone-receptor superfamily as possible UF-binding proteins, and competition experiments suggest that the chicken ovalbumin upstream promoter transcription factor functions as such in the rabbit endometrium.

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