An element in intron 1 of the CFTR gene augments intestinal expression in vivo.
The elements controlling the complex developmental and tissue-specific expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene lie outside the basal promoter region and have not been characterized. We previously identified a tissue-specific DNase I hypersensitive site (DHS) in intron 1 (185 + 10 kb) of the CFTR gene. Here we show that removal of the core element abolishes the activity of this DHS in transient transfection assays of reporter/enhancer gene constructs. We then compared expression from a 310 kb yeast artificial chromosome (YAC) that contains the entire CFTR gene with expression from the same YAC from which the DHS element had been deleted. Stable transfection of a human colon carcinoma cell line showed that transcription from the deleted YAC was reduced by approximately 60%. In transgenic mice, deletion of the intron 1 DHS had no effect on expression in the lung, but reduced expression in the intestine by approximately 60%. Thus, the regulatory element associated with the intron 1 DHS is tissue-specific and is required for normal CFTR expression levels in the intestinal epithelium in vivo.
Rowntree
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RK
Paediatric Molecular Genetics, Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
Vassaux
G
G
McDowell
T L
TL
Howe
S
S
McGuigan
A
A
Phylactides
M
M
Huxley
C
C
Harris
A
A
D000818:Animals; D018938:Caco-2 Cells; D002460:Cell Line; D018244:Chromosomes, Artificial, Yeast; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007438:Introns; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D016133:Polymerase Chain Reaction; D012045:Regulatory Sequences, Nucleic Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic; D014162:Transfection
C505032:CFTR protein, human; D004268:DNA-Binding Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003850:Deoxyribonuclease I