Nuclear factor I/thyroid transcription factor 1 interactions modulate surfactant protein C transcription.
Surfactant protein C (SP-C; Sftpc) gene expression is restricted to pulmonary type II epithelial cells. The proximal SP-C promoter region contains critical binding sites for nuclear factor I (NFI) and thyroid transcription factor 1 (TTF-1; also called Nkx2.1). To test the hypothesis that NFI isoforms interact with TTF-1 to differentially regulate SP-C transcription, we performed transient transfection assays in JEG-3 cells, a choriocarcinoma cell line with negligible endogenous NFI or TTF-1 activity. Cotransfection of NFI family members with TTF-1 induced synergistic activation of the SP-C promoter that was further enhanced by p300. TTF-1 directly interacts with the conserved DNA binding and dimerization domain of all NFI family members in coimmunoprecipitation and mammalian two-hybrid experiments. To determine whether SP-C expression is regulated by NFI in vivo, a chimeric fusion protein containing the DNA binding and dimerization domain of NFI-A and the Drosophila engrailed transcriptional repression domain (NFIen) was conditionally expressed in mice under control of a doxycycline-inducible transgene. Induction of NFIen in a subset of type II cells inhibited SP-C gene expression without affecting expression of TTF-1 in doxycycline-treated double-transgenic mice. Taken together, these findings support the hypothesis that NFI family members interact with TTF-1 to regulate type II cell function.
Bachurski
Cindy J
CJ
Division of Pulmonary Biology, Cincinnati Children's Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA. Cindy.Bachurski@cchmc.org
Yang
Guan Hu
GH
Currier
Tracey A
TA
Gronostajski
Richard M
RM
Hong
Dihua
D
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D051839:NFI Transcription Factors; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000378:metabolism; D037721:Pulmonary Surfactant-Associated Protein C / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; C497592:NFIA protein, human; C000614412:NKX2-1 protein, human; C497646:Nfia protein, mouse; C000614414:Nkx2-1 protein, mouse; D009687:Nuclear Proteins; D020033:Protein Isoforms; D037721:Pulmonary Surfactant-Associated Protein C; D011993:Recombinant Fusion Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D004247:DNA