1.3 kilobases of the lung type I cell T1α gene promoter mimics endogenous gene expression patterns during development but lacks sequences to enhance expression in perinatal and adult lung
✍ Scribed by Maria I. Ramirez; Yu Xia Cao; Mary C. Williams
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 822 KB
- Volume
- 215
- Category
- Article
- ISSN
- 1058-8388
No coin nor oath required. For personal study only.
✦ Synopsis
The T1␣ gene is one of few markers for the type I cell phenotype in the adult mammalian lung. Type I cells form a large, thin epithelial layer that facilitates gas exchange and transport of fluids between the air spaces and capillaries. The T1␣ gene has a complex pattern of developmental expression in lung and brain; in vitro studies indicate that expression is regulated in part by thyroid transcription factor 1, forkhead proteins, and Sp1/Sp3 proteins. To explore the mechanisms that confine T1␣ expression in intact adult animals to alveolar type I and choroid plexus epithelial cells, we generated mice bearing a 1.3-kb T1␣ promoter-chloramphenicol acetyltransferase (CAT) gene. In situ hybridization and RNase protection assays show that the 1.3-kb promoter confers a pattern of CAT expression that largely matches the endogenous T1␣ in embryos and mid-term fetuses in lung and central nervous system. However, the 1.3-kb promoter lacks elements important for perinatal up-regulation of T1␣ in the lung and maintenance of that expression in the adult lung and brain. The final adult pattern of T1␣ expression may be directed by elements outside the 1.3-kb fragment, perhaps those 5' to the 1.3-kb fragment as we show herein, or in 3' and intronic regions.