FIG. 8.

COS-7 cells were transfected with TR (160 ng) or a luciferase reporter (500 ng) driven by the thymidine kinase promoter and controlled by either the ME or MHC gene TRE or a TRE containing two copies of PAL, an internal control Renilla reporter (100 ng) and pCDM8 carrier DNA (740 ng). (A) T₃ induction of each TRE mediated by each receptor. Luciferase activity was normalized to Renilla to control for transfection efficiency, and the results are expressed as mean T₃ induction ratio (with standard errors shown), calculated by dividing normalized luciferase activities following T₃ treatment by basal values. (B) Induction of each TRE mediated by each receptor in the absence or presence of hormone. Luciferase activity was normalized to Renilla to control for transfection efficiency and the results shown as reporter gene activity in the absence (−) or presence (+) of T₃ relative to the level of reporter gene activity under each condition in the absence of cotransfected receptor, which was normalized to a value of 1. Values below 1 in the absence of T₃ indicate repression by unliganded receptor; values above 1 after addition of T₃ indicate gene activation. (C) Complete data that were plotted in panels A and B, showing the values for mean basal (−T₃) and T₃-induced (+T₃) luciferase/Renilla ratios as well as T₃ induction ratios (standard errors are given). Basal and T₃-induced values are relative to reporter gene activity in the absence of cotransfected receptor, which was normalized to a value of 1.