Identification of a novel DNA regulatory element in the rabbit surfactant protein B (SP-B) promoter that is a target for ATF/CREB and AP-1 transcription factors.
Surfactant protein B (SP-B) is required for the maintenance of biophysical properties and physiological function of pulmonary surfactant. SP-B is expressed in a cell/tissue-specific manner by the alveolar type II and bronchiolar (Clara) epithelial cells of the lung and is developmentally and hormonally regulated. We previously identified a minimal promoter region containing -236/+39 base pairs (bp) of rabbit SP-B gene that is necessary and sufficient for high level promoter activity in NCI-H441 cells, a cell line with characteristics of Clara cells. In this study, we have characterized the functional importance of a novel DNA regulatory element, termed SP-B CRE, with the sequence TGAGGTCA in the SP-B minimal promoter. The SP-B CRE sequence shared homology to cyclic AMP responsive element (CRE) binding sequence and contained an overlapping nuclear receptor element binding half-site. Mutation of SP-B CRE into a scrambled sequence reduced promoter activity by greater than 70%, whereas mutation into a palindromic consensus CRE increased the promoter activity by 100%. Electrophoretic mobility shift assay (EMSA) and Western immunoblot analysis of affinity purified proteins interacting with SP-B CRE showed that it is a target for binding of members of the activating transcription factor (ATF)/cyclic AMP response element binding protein (CREB) family of transcription factors, such as CREB, CREM, ATF-1, ATF-2 as well as c-Jun and TTF-1. Overexpression of CREB, ATF-2 and c-Jun inhibited SP-B promoter activity in NCI-H441 cells. These data have shown that members of the ATF/CREB family of transcription factors and c-Jun play important roles in mediating the transcriptional regulation of the SP-B gene.
Berhane
K
K
Department of Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX 75708-3154, USA.
Boggaram
V
V
D051698:Activating Transcription Factor 2; D051696:Activating Transcription Factors; D000818:Animals; D001798:Blood Proteins / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology; D006801:Humans; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011510:Proteolipids / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D011817:Rabbits; D012045:Regulatory Sequences, Nucleic Acid; D020218:Response Elements; D012689:Sequence Homology, Nucleic Acid; D000074482:Thyroid Nuclear Factor 1; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000494:pharmacology; D014407:Tumor Cells, Cultured
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D051696:Activating Transcription Factors; D001798:Blood Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D016207:Cytokines; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D011510:Proteolipids; D016755:Proto-Oncogene Proteins c-jun; D011663:Pulmonary Surfactants; D000074482:Thyroid Nuclear Factor 1; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D016211:Transforming Growth Factor alpha; D000242:Cyclic AMP