Identification of retinoic acid receptor element in human cholesteryl ester transfer protein gene

The transcriptional regulation of the human cholesteryl ester transfer prot ein (CETP) gene by retinoic acid was investigated by a transient transfecti on assay. A series of deleted vectors generated from the 5'-upstream region (3434 bp) of the CETP gene linked to the luciferase reporter gene was indi vidually transfected to HepG2 cells, Promoter analyses revealed essential r egulatory machinery in the -110/-40 region of the upstream sequence of the human CETP gene. When the cells transfected with the reporter vectors were stimulated with all-trans retinoic acid (tRA), the hormone response was dra stically reduced when the -165/-110 region was deleted, thereby suggesting that there may be a retinoic acid receptor element (RARE) in the region. A footprinting analysis showed that the DNA segment at the -165/-134 is prote cted by the HepG2 nuclear extract. A competition analysis on the gel mobili ty shift assay using consensus RARE and a purified retinoic acid receptor c onfirmed the -165/-134 region as being RARE. (C) 1999 Academic Press.