Figure 3.

Ability of exogenous follicular TG to modulate TG, TPO, TSHR, or MHC class I promoter activity in rat FRTL-5 thyroid cells, as assessed by transient expression analysis. FRTL-5 cells in 6H medium were transfected with 5 μg of the noted chimera DNAs or their control vectors. After 24 hr, cells were washed and exposed to 10 mg/ml TG or BSA as in Fig. 1. After 48 hr, promoter activity was measured and normalized for transfection efficiency. Values are expressed relative to values measured in the presence of TG vs. BSA; a ratio of 1 indicates no TG effect. Data are the mean ± SD of three different experiments. One or two asterisks represent a significant TG-induced decrease or increase at P < 0.05 or P < 0.01, respectively.