HNF1alpha is involved in tissue-specific regulation of CFTR gene expression

Mouchel, Nathalie; Henstra, Sytse A.; McCarthy, Victoria A.; Williams, S. Henry; Phylactides, Marios; Harris, Ann

doi:10.1042/bj20031157

Cited by 57 publications

(71 citation statements)

References 44 publications

(58 reference statements)

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“…We would predict that removal of multiple enhancer sites and the promoter would be required to completely extinguish CFTR expression in any epithelial cell type. We demonstrate here that one of the tissue-specific transcription factors interacting with the enhancers in intestinal cells is HNF1, which we have previously shown to be involved in CFTR expression both in vitro and in vivo through interactions at multiple intronic sites (27,28). HNF1 has been implicated in a similar mechanism of transcriptional regulation in the human ADH gene, where it binds a distal enhancer and augments gene expression (34).…”

Section: Discussionmentioning

confidence: 93%

“…Additional cell-line specific DHS are evident in intron 10 (1716 ϩ 13.2 kb) in Caco2 cells and intron 18 (3600 ϩ 1.6 kb) in HT29. The intron 10 site encompasses two closely spaced DHS at 1716 ϩ 13.2 kb and ϩ13.7 kb, that were characterized in our previous work (22,23,28). Also of interest are the DHS located -35 kb and -44 kb with respect to the CFTR translational start site in primary epididymis cells.…”

Section: Resultsmentioning

confidence: 99%

“…The mechanism of interaction between these intronic enhancer sequences and the CFTR promoter is of significant interest and is likely to involve multiple protein complexes, including tissuespecific transcription factors and general factors, including chromatin remodeling enzymes and proteins associated with the nuclear scaffold (27,28,30,31). We previously showed that hepatocyte nuclear factor 1 (HNF1) binds directly to the core element within the intron 1 DHS and is necessary for enhancer activity (27).…”

Section: In Vivo Association Of Hnf1 and P300 With Cftr Regulatory Elmentioning

confidence: 99%

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Intronic enhancers coordinate epithelial-specific looping of the active CFTR locus

Ott

Blackledge

Kerschner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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The regulated expression of large human genes can depend on long-range interactions to establish appropriate three-dimensional structures across the locus. The cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encompasses 189 kb of genomic DNA, shows a complex pattern of expression with both spatial and temporal regulation. The flanking loci, ASZ1 and CTTNBP2, show very different tissue-specific expression. The mechanisms governing control of CFTR expression remain poorly understood, although they are known to involve intronic regulatory elements. Here, we show a complex looped structure of the CFTR locus in cells that express the gene, which is absent from cells in which the gene is inactive. By using chromatin conformation capture (3C) with a bait probe at the CFTR promoter, we demonstrate close interaction of this region with sequences in the middle of the gene about 100 kb from the promoter and with regions 3 to the locus that are about 200 kb away. We show that these interacting regions correspond to prominent DNase I hypersensitive sites within the locus. Moreover, these sequences act cooperatively in reporter gene constructs and recruit proteins that modify chromatin structure. The model for CFTR gene expression that is revealed by our data provides a paradigm for other large genes with multiple regulatory elements lying within both introns and intergenic regions. We anticipate that these observations will enable original approaches to designing regulated transgenes for tissue-specific gene therapy protocols.cis-acting elements ͉ enhancer:promoter interactions ͉ regulation of expression ͉ cystic fibrosis transmembrane conductance regulator U nderstanding the three-dimensional organization of individual loci within the human genome and how this relates to the regulation of gene expression is the focus of intense study. Many new technologies are being developed to locate and classify the functional elements of the human genome (1). These elements may contribute to the transcription of ubiquitously expressed genes and are also likely responsible for regulating genes with expression that is temporally and spatially controlled. Cis-acting regulatory elements located within noncoding regions of genomic DNA can influence the organization of chromosomes and the transcriptional activity of genes. These cis sequences include distal enhancers that may reside large distances from the gene promoters they control. Variations in these enhancer/promoter interactions and the nuclear localization of the genes they regulate are thought to be contributing factors in the diversity of transcriptional profiles between different cell types. Moreover, they are important in adjusting these profiles throughout cellular differentiation and development (2-7). These long-range associations are facilitated by the looping of chromatin, whereby regulatory elements come together with requisite nuclear factors to function within ''transcriptional hubs'' where transcriptional activity is coordinated (8).Here, we present...

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Section: Discussionmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: In Vivo Association Of Hnf1 and P300 With Cftr Regulatory Elmentioning

confidence: 99%

See 1 more Smart Citation

Intronic enhancers coordinate epithelial-specific looping of the active CFTR locus

Ott

Blackledge

Kerschner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

104

211

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“…39 Alternatively, ATP8B1 defect could affect the transcriptional activity not only of FXR, 13 but also of other transcription factors, like HNF1, which regulate the tissue-specific expression of CFTR. 40 Because CFTR is a major determinant of hydroelectrolytic secretion in the biliary tract, 20,[41][42][43] CFTR downregulation may contribute to impaired bile secretion through bile inspissation in PFIC1. This would explain the typical ultrastructural abnormality of bile in PFIC1 termed "Byler bile", characterized by a coarsely granular appearance.…”

Section: Discussionmentioning

confidence: 99%

Altered hepatobiliary gene expressions in PFIC1: ATP8B1 gene defect is associated with CFTR downregulation

et al. 2006

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Recent reports in patients with PFIC1 have indicated that a gene defect in ATP8B1 could cause deregulations in bile salt transporters through decreased expression and/or activity of FXR. This study aimed to: (1) define ATP8B1 expression in human hepatobiliary cell types, and (2) determine whether ATP8B1 defect affects gene expressions related to bile secretion in these cells. ATP8B1 expression was detected by RT-PCR in hepatocytes and cholangiocytes isolated from normal human liver and gallbladder. ATP8B1 mRNA levels were 20-and 200-fold higher in bile duct and gallbladder epithelial cells, respectively, than in hepatocytes. RT-PCR analyses of the liver from two patients with PFIC1, one with PFIC2, one with biliary atresia, showed that, compared to normal liver, hepatic expressions of FXR, SHP, CYP7A1, ASBT were decreased at least by 90% in all cholestatic disorders. In contrast, NTCP transcripts were less decreased (by <30% vs. 97%) in PFIC1 as compared with other cholestatic disorders, while BSEP transcripts, in agreement with BSEP immunohistochemical signals, were normal or less decreased (by 50% vs. 97%). CFTR hepatic expression was decreased (by 80%), exclusively in PFIC1, while bile duct mass was not reduced, as ascertained by cytokeratin-19 immunolabeling. In Mz-ChA-2 human biliary epithelial cells, a significant decrease in CFTR expression was associated with ATP8B1 invalidation by siRNA. In conclusion, cholangiocytes are a major site of ATP8B1 hepatobiliary expression. A defect of ATP8B1 along with CFTR downregulation can impair the contribution of these cells to bile secretion, and potentially explain the extrahepatic cystic fibrosis-like manifestations that occur in PFIC1. (HEPATOLOGY 2006;43:1125-1134 P rogressive familial intrahepatic cholestasis (PFIC) represents a heterogeneous group of inherited disorders, in which cholestasis starts in infancy and generally leads to liver failure in childhood. Three types of PFIC, caused by mutations in three separate genes, are currently recognized. The first two types, PFIC1 and 2, share common phenotypic features, including normal or nearly normal serum ␥-glutamyl transpeptidase activity and little bile duct proliferation, that are unusual in other types of cholestatic liver diseases. 1 In PFIC2, mutations affect the ABCB11 gene, which encodes a bile salt transporter, the canalicular bile salt export pump (BSEP). 2 Thus, a defect in the extrusion of bile salts across the canalicular membrane of hepatocytes is the primary cause of cholestasis in PFIC2. In PFIC1, mutations affect the ATP8B1 gene, which encodes a protein also called FIC1. 3 ATP8B1 protein belongs to a subfamily of P-type adenosine triphosphatases. Two members of this subfamily including ATP8B1 have been reported to mediate aminophospholipid translocation in plasma membranes. 4,5 The physiological function of ATP8B1 protein and the mechanisms by which ATP8B1 deficiency leads to PFIC1 disease remain poorly understood. It was previously shown that ATP8B1 is expressed in different tissues such as th...

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“…Interestingly, these two proteins are also expressed in the intestinal epithelium but little is known about their function in this organ. To date, several studies have demonstrated that these transcription factors activate the expression of a number of intestinal genes including Fabp1, LPH, Cftr and Glc-6-Pase, which are expressed in differentiated enterocytes (Mouchel et al, 2004;Gautier-Stein et al, 2006;Bosse et al, 2007). An in vitro study demonstrated that Hnf1a and b control the transcription of Dpp4, another marker of differentiated enterocytes (Erickson et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Hepatocyte nuclear factor 1α and β control terminal differentiation and cell fate commitment in the gut epithelium

et al. 2010

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SUMMARYThe intestinal epithelium is a complex system characterized by massive and continuous cell renewal and differentiation. In this context, cell-type-specific transcription factors are thought to play a crucial role by modulating specific transcription networks and signalling pathways. Hnf1a and b are closely related atypical homeoprotein transcription factors expressed in several epithelia, including the gut. With the use of a conditional inactivation system, we generated mice in which Hnf1b is specifically inactivated in the intestinal epithelium on a wild-type or Hnf1a -/-genetic background. Whereas the inactivation of Hnf1a or Hnf1b alone did not lead to any major intestinal dysfunction, the concomitant inactivation of both genes resulted in a lethal phenotype. Double-mutant animals had defective differentiation and cell fate commitment. The expression levels of markers of all the differentiated cell types, both enterocytes and secretory cells, were affected. In addition, the number of goblet cells was increased, whereas mature Paneth cells were missing. At the molecular level, we show that Hnf1a and b act upstream of the Notch pathway controlling directly the expression of two crucial components: Jag1 and Atoh1. We demonstrate that the double-mutant mice present with a defect in intestinal water absorption and that Hnf1a and b directly control the expression of Slc26a3, a gene whose mutations are associated with chloride diarrhoea in human patients. Our study identifies new direct target genes of the Hnf1 transcription factors and shows that they play crucial roles in both defining cell fate and controlling terminal functions in the gut epithelium. KEY WORDS: Gut epithelium, Hnf1, Commitment, Differentiation, MouseHepatocyte nuclear factor 1a and b control terminal differentiation and cell fate commitment in the gut epithelium

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HNF1alpha is involved in tissue-specific regulation of CFTR gene expression

Cited by 57 publications

References 44 publications

Intronic enhancers coordinate epithelial-specific looping of the active CFTR locus

Intronic enhancers coordinate epithelial-specific looping of the active CFTR locus

Altered hepatobiliary gene expressions in PFIC1: ATP8B1 gene defect is associated with CFTR downregulation

Hepatocyte nuclear factor 1α and β control terminal differentiation and cell fate commitment in the gut epithelium

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