Cis-active elements controlling lung cell-specific expression of human pulmonary surfactant protein B gene.

摘要: Human surfactant protein B (SPB) is a 79-amino-acid hydrophobic that enhances the surface active properties of pulmonary surfactant. SPB expressed in nonciliated bronchiolar and alveolar type II cells respiratory epithelium, its expression increases markedly late gestation. In present study, human adenocarcinoma cell line, H441, was used both functional biochemical assays to identify DNA sequences controlling lung cell-specific gene. DNase I hypersensitive studies demonstrated two distinct regions hypersensitivity located proximal promoter within eighth intron To functionally define these sequences, series plasmid vectors were constructed which segments gene 5'-flanking sequence linked CAT reporter assayed for nonlung lines. Whereas far upstream intronic did not contain enhancer-like elements, 259-base pair segment (base -218 +41) sufficient support expression. footprinting this epithelial fragment contained five nuclear protein-binding sites, bound complexes. These results suggest determined, part, by ubiquitous type-specific protein-DNA interactions region.