Identification of surfactant protein B (SP-B) genomic regions required for lung-specific expression in transgenic mice.

摘要

Pulmonary surfactant maintains the integrity of the alveoli by reducing surface tension at the alveolar air-tissue interface. Surfactant protein B (SP-B), a cell/tissue-specific and developmentally regulated protein, is essential for the maintenance of biophysical properties and physiological function of surfactant. We used transgenic mice to identify rabbit SP-B genomic regions that control cell/tissue-specific and developmental regulation of expression. The data indicated that although a fragment consisting of -2176/+39 base pairs of SP-B gene failed to direct expression of chloramphenicol acetyltransferase (CAT) reporter gene, a shorter fragment consisting of -730/+39 base pairs expressed CAT in a tissue-specific manner in lungs of transgenic mice. Immunostaining experiments showed CAT expression in cells with characteristics of alveolar type II and bronchiolar (Clara) epithelial cells. The developmental expression of CAT was similar or identical to the expression of endogenous SP-B gene in transgenic mice. These data indicated that the -730/+39 base pair region of SP-B gene contains cis-DNA regulatory elements necessary for cell/tissue-specific and developmental regulation of expression.