FIG. 8.

Transient transfection assay for functional elements upstream of the B-region GREs. (A) Sequence organization of LTR-luciferase constructions in the Nuc-B and -C region. Shown are the B-region GREs (gray bar) and two binding sites for GR in the 3′ region of the Nuc-C family (black bars) (33). MMTV sequences present in the pM-Luc, pFL-Luc, pFLΔB-Luc, and pFLΔC-Luc constructions are schematized. (B) Activity for each of the constructs is presented with or without the addition of dexamethasone. Luciferase expression from the LTR constructions is shown normalized to the expression of a cotransfected simian virus 40–β-galactosidase plasmid.