Nuclear factor I family members regulate the transcription of surfactant protein-C.
Transcription of the surfactant protein-C (SP-C) gene is restricted to Type II epithelial cells in the adult lung. We have shown previously that the 0.32-kilobase pair (kb) mouse SP-C promoter is functional in transient transfection assays of the lung epithelial cell-derived cell line, MLE-15, and that thyroid transcription factor 1 (TTF-1) transactivates promoter activity. The 0.32-kb SP-C promoter can be separated into a proximal promoter region (-230 to +18) and an enhancer region (-318 to -230). Three DNase I footprints were mapped in the promoter region (C1 through C3) and two in the enhancer region (C4 and C5). We now show that nuclear factor I (NFI) family members bind to both individual NFI half-sites in footprints C1, C3, and C5, and to a composite site in footprint C4 by competition gel retardation and antibody supershift analyses. Mutational analysis of the 0.32-kb mouse SP-C promoter and transient transfection of MLE-15 cells demonstrated that the NFI binding sites are required for promoter activity in this cell type. Site-specific mutation of the proximal or distal NFI sites drastically reduced transactivation by a co-transfected NFI-A expression vector in HeLa cells. These data indicate that NFI family member(s), binding to sites in both the promoter and enhancer regions, regulate SP-C gene expression in a process independent of TTF-1.
Bachurski
C J
CJ
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA. cindy.bachurski@chmcc.org
Kelly
S E
SE
Glasser
S W
SW
Currier
T A
TA
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000502:physiology*; D003850:Deoxyribonuclease I / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic; D011510:Proteolipids / Q000235:genetics*; D011663:Pulmonary Surfactants / Q000235:genetics*; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; C497592:NFIA protein, human; C497646:Nfia protein, mouse; D009687:Nuclear Proteins; D011510:Proteolipids; D011663:Pulmonary Surfactants; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D003850:Deoxyribonuclease I