| First Author | Mallampalli RK | Year | 2002 |
| Journal | Biochem J | Volume | 362 |
| Issue | Pt 1 | Pages | 81-8 |
| PubMed ID | 11829742 | Mgi Jnum | J:75012 |
| Mgi Id | MGI:2159547 | Doi | 10.1042/0264-6021:3620081 |
| Citation | Mallampalli RK, et al. (2002) Lipid deprivation increases surfactant phosphatidylcholine synthesis via a sterol-sensitive regulatory element within the CTP:phosphocholine cytidylyltransferase promoter. Biochem J 362(Pt 1):81-8 |
| abstractText | Lipid-deprived mice increase alveolar surfactant disaturated phosphatidylcholine (DSPtdCho) synthesis compared with mice fed a standard diet by increasing expression of CTP:phosphocholine cytidylyltransferase (CCT), the rate-limiting enzyme for DSPtdCho synthesis. We previously observed that lipid deprivation increases mRNA synthesis for CCT [Ryan, McCoy, Mathur, Field and Mallampalli (2000) J. Lipid Res. 41, 1268-1277]. To evaluate regulatory mechanisms for this gene, we cloned the proximal approximately 1900 bp of the 5' flanking sequence of the murine CCT gene, coupled this to a luciferase reporter, and examined transcriptional regulation in a murine alveolar epithelial type II cell line (MLE-12). The core promoter was localized to a region between -169 and +71 bp, which exhibited strong basal activity comparable with the simian virus 40 promoter. The full-length construct, from -1867 to +71, was induced 2-3-fold when cells were cultured in lipoprotein-deficient serum (LPDS), similar to the level of induction of the endogenous CCT gene. By deletional analysis the sterol regulatory element (SRE) was localized within a 240 bp region. LPDS activation of the CCT promoter was abolished by mutation of this SRE, and gel mobility-shift assays demonstrated specific binding of recombinant SRE-binding protein to this element within the CCT promoter. These observations indicate that sterol-regulated expression of CCT is mediated by an SRE within its 5' flanking region. |
