Identification of functional TTF-1 and Sp1/Sp3 sites in the upstream promoter region of rabbit SP-B gene.
Surfactant protein B (SP-B) is essential for the maintenance of biophysical properties and physiological function of pulmonary surfactant. SP-B mRNA is expressed in a cell type-restricted manner in alveolar type II and bronchiolar (Clara) epithelial cells of the lung and is developmentally induced. In NCI-H441 cells, a lung cell line with characteristics of Clara cells, a minimal promoter region comprising -236 to +39 nucleotides supports high-level expression of chloramphenicol acetyltransferase reporter activity. In the present investigation, we characterized the upstream promoter region, -236 to -140 nucleotides, that is essential for promoter activity. Deletion mapping identified two segments, -236 to -170 and -170 to -140 nucleotides, that are important for promoter activity. Mutational analysis and gel mobility shift experiments identified thyroid transcription factor-1, Sp1, and Sp3 as important trans-acting factors that bind to sequences in the upstream promoter region. Our data suggest that SP-B promoter activity is dependent on interactions between factors bound to upstream and downstream regions of the promoter.
Margana
R
R
Department of Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708-3154, USA.
Berhane
K
K
Alam
M N
MN
Boggaram
V
V
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology*; D011510:Proteolipids / Q000235:genetics*; D011663:Pulmonary Surfactants / Q000235:genetics*; D011817:Rabbits; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051704:Sp2 Transcription Factor; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D011510:Proteolipids; D011663:Pulmonary Surfactants; D016329:Sp1 Transcription Factor; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D051704:Sp2 Transcription Factor; D004247:DNA