Regulation of human Clara cell 10 kD protein expression by chicken ovalbumin upstream promoter transcription factors (COUP-TFs).
Clara cell 10 kD protein (CC10) is expressed specifically in a portion of nonciliated airway epithelial cells. The molecular mechanisms that determine its high specificity are not clear. Transcription factors implicated in the regulation of CC10 in rodents do not show the same level of cell specificity. We report here that a 3.3 kb human CC10 DNA fragment, containing the 5' flanking region and promoter, directs lacZ reporter expression in a small portion of Clara cells of the airway epithelia of transgenic mice, indicating the requirement of additional regulatory elements for expression. Addition of an intron containing a transcription enhancer from the human cytokeratin 18 gene greatly enhances the level of transgene expression and broadens epithelial specificity. To gain insight into the mechanisms underlying the cell specificity of human CC10 expression, we performed a promoter analysis of the CC10 gene and a yeast one-hybrid screening to identify factors that regulate the promoter. We have found that chicken ovalbumin upstream promoter transcription factors (COUP-TFs) interact with a proximal promoter region and confirmed the interaction by gel-shift assays. Cotransfection analyses with reporter constructs in cultured cells indicated that COUP-TFs inhibit human CC10 expression. These experiments suggest that COUP-TFs may play a pivotal role in cell specificity of the human CC10 gene by inhibiting its expression in nonpermissive cells.
Lung Biology Research Programme and Canadian Institutes of Health Research Group in Lung Development, Hospital for Sick Children.
Roya
R
Navab
Yimin
Y
Wang
Yu-Hua
YH
Chow
Anan
A
Wang
Robert P
RP
Jankov
Norio
N
Takamoto
Sophia Y
SY
Tsai
Ming-Jer
MJ
Tsai
A Keith
AK
Tanswell
Jim
J
Hu
D000818:Animals; D051838:COUP Transcription Factor I; D051836:COUP Transcription Factors; D002478:Cells, Cultured; D002645:Chickens; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D011987:Receptors, Steroid; D012045:Regulatory Sequences, Nucleic Acid; D017384:Sequence Deletion; D014132:Trachea / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014598:Uteroglobin
D051838:COUP Transcription Factor I; D051836:COUP Transcription Factors; D004268:DNA-Binding Proteins; C497589:NR2F1 protein, human; C497590:Nr2f1 protein, mouse; D011506:Proteins; D011987:Receptors, Steroid; C556389:SCGB1A1 protein, human; C556390:Scgb1a1 protein, mouse; D014157:Transcription Factors; D010047:Ovalbumin; D014598:Uteroglobin