| Summary: | Expression of the rat liver neutral cytosolic cholesteryl ester hydrolase (CEH) gene is regulated by glucocorticoids, thyroxine, and agents that perturb cholesterol metabolism. The present studies identify the putative hormone response elements in the CEH promoter. They also define the roles of two previously identified sterol regulatory elements (SRE-92 and SRE-160) and a putative nuclear factor-Y (NF-Y) binding site with a consensus ATTGG (inverted CCAAT) motif (Natarajan, R., S. Ghosh, and W. M. Grogan. 1998. Biochem. Biophys. Res. Commun. 243: 349–355). CEH promoter-reporter gene constructs were transiently transfected into HepG2 cells to evaluate promoter activity. Results indicated that the CEH gene has two complex glucocorticoid response units in distal portions of the promoter corresponding to consensus glucocorticoid regulatory sequences as well as putative thyroid hormone response elements. CEH promoter-reporter constructs with the proximal 189 bp of the wild-type or mutated sequences were also transfected into HepG2 cells. Activity of the wild-type construct increased when incubated in sterol depleted media or when co-expressed with a mature sterol regulatory element binding protein (SREBP-2). These responses were suppressed by mutations in SRE-92, SRE-160, or NF-Y, indicating that these cis elements are sufficient for sterol-mediated regulation of the CEH promoter. Gel mobility shift assays further demonstrated that NF-Y binds to the inverted CCAAT box motif and is required for the sterol-mediated regulation. These results indicate that multiple cis-elements regulate transcription of the cholesteryl ester hydrolase (CEH) gene, consistent with the reported regulation of CEH expression.—Natarajan, R., S. Ghosh, and W. M. Grogan. Regulation of the rat neutral cytosolic cholesteryl ester hydrolase promoter by hormones and sterols: a role for nuclear factor-Y in the sterol-mediated response. J. Lipid Res. 1999. 40: 2091–2098.
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