Binding of serum response factor to cystic fibrosis transmembrane conductance regulator CArG-like elements, as a new potential CFTR transcriptional regulation pathway.
CFTR expression is tightly controlled by a complex network of ubiquitous and tissue-specific cis-elements and trans-factors. To better understand mechanisms that regulate transcription of CFTR, we examined transcription factors that specifically bind a CFTR CArG-like motif we have previously shown to modulate CFTR expression. Gel mobility shift assays and chromatin immunoprecipitation analyses demonstrated the CFTR CArG-like motif binds serum response factor both in vitro and in vivo. Transient co-transfections with various SRF expression vector, including dominant-negative forms and small interfering RNA, demonstrated that SRF significantly increases CFTR transcriptional activity in bronchial epithelial cells. Mutagenesis studies suggested that in addition to SRF other co-factors, such as Yin Yang 1 (YY1) previously shown to bind the CFTR promoter, are potentially involved in the CFTR regulation. Here, we show that functional interplay between SRF and YY1 might provide interesting perspectives to further characterize the underlying molecular mechanism of the basal CFTR transcriptional activity. Furthermore, the identification of multiple CArG binding sites in highly conserved CFTR untranslated regions, which form specific SRF complexes, provides direct evidence for a considerable role of SRF in the CFTR transcriptional regulation into specialized epithelial lung cells.
René
Céline
C
Laboratoire de Génétique Moléculaire et Chromosomique, Institut Universitaire de Recherche Clinique, Montpellier, France.
Taulan
Magali
M
Iral
Florence
F
Doudement
Julien
J
L'Honoré
Aurore
A
Gerbon
Catherine
C
Demaille
Jacques
J
Claustres
Mireille
M
Romey
Marie-Catherine
MC
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D017124:Conserved Sequence; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D032342:Muscle Cells / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020545:Respiratory Mucosa / Q000378:metabolism*; D027602:Serum Response Element; D026362:Serum Response Factor / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D050986:YY1 Transcription Factor
C505032:CFTR protein, human; D002843:Chromatin; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D026362:Serum Response Factor; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C494698:YY1 protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator