Interaction of intestinal and pancreatic transcription factors in the regulation of CFTR gene expression.
The tissue-specific regulation of the cystic fibrosis transmembrane conductance regulator gene (CFTR) is coordinated by intronic and extragenic cis-acting elements that influence its transcriptional activity. The promoter apparently lacks sequences to drive cell type-specific expression. We previously identified a number of intronic elements that were associated with DNase I hypersensitive sites (DHS) and bound the hepatocyte nuclear factor 1 (HNF1) transcription factor. Moreover, we demonstrated the likely involvement of HNF1 in the regulation of CFTR expression in vivo. Here we investigate DHS in introns 16 and 17a of the CFTR gene, which are evident in intestinal and pancreatic cell lines, and determine the transcription factors that interact with these sites. Of particular interest were factors known to interact with HNF1 in coordinated expression of genes in the gastrointestinal tract. We demonstrate that though sequences within these DHS bind HNF1, CDX2, and PBX1 in vitro, only PBX1 show a robust in vivo interaction. These data contribute to our understanding of the complexity of cell-type-specific CFTR regulatory mechanisms.
Paediatric Molecular Genetics, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.
Victoria A
VA
McCarthy
Christopher J
CJ
Ott
Marios
M
Phylactides
Ann
A
Harris
D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D000071616:CDX2 Transcription Factor; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics* / Q000378:metabolism; D018983:DNA Footprinting / Q000379:methods; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D015972:Gene Expression Regulation, Neoplastic; D051538:Hepatocyte Nuclear Factor 1-alpha / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D007438:Introns / Q000235:genetics; D010179:Pancreas / Q000378:metabolism / Q000473:pathology; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D018398:Homeodomain Proteins; D000075062:Pre-B-Cell Leukemia Transcription Factor 1; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C083400:PBX1 protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003850:Deoxyribonuclease I