FIG. 1.

Screening of an SREBP-1 knockout mouse adipose tissue expression library to identify cDNA clones which activate the SREBP-1c promoter. An expression cDNA library from the adipose tissues of SREBP-1-null mice was constructed as described in Materials and Methods. A luciferase reporter gene containing the mouse SREBP-1c promoter (2.6 kb), pBP1c2600-Luc, and each subpool containing approximately 1,500 cDNA clones were cotransfected into HEK 293 cells with pSV-βgal as a reference plasmid. Luciferase activity was measured and normalized by β-galactosidase activity. After several rounds of screening, six positive single clones were isolated from the library (three LXRα and three LXRβ). A representative result from the initial screening is shown.