Figure 6

Selenium and thioredoxin reductase 1 (TRR1) reduce transactivation by Tat. (A) Transfected cells were split 6 hours post-transfection into aliquots and exposed to the indicated concentrations of sodium selenite for 18 hours before analysis. The inset legend indicates the columns corresponding to each effector/reporter combination. Asterisks indicate statistical significance by the Wilcoxon rank-sum test (p < 0.05) for selenium treated samples compared to vehicle treated samples (B) C33a cells were co-transfected with Tat expression and reporter plasmids and indicated amounts of a TRR1 expression plasmid. pcDNA3.1 was used to normalize the amount of DNA used per transfection. Transfections was split six hours post-transfection, and half the transfected cells were exposed to 0.03 μM sodium selenite for an additional 18 hours before analysis. Transactivation is expressed as a percent of transactivation observed in the absence of co-transfected pTRR1 or added sodium selenite (control conditions). The inset legend indicates the columns corresponding to co-transfected pTRR1 alone, or co-transfected pTRR1 with sodium selenite addition. Asterisks indicate statistical significance by the Wilcoxon rank-sum test (p < 0.05) for TRR1 transfected cells compared to controls in which pcDNA3.1 was co-transfected with reporter and effector plasmids, and cells were not exposed to sodium selenite. (C) Immunoblot analysis indicates that treatment with sodium selenite does not alter the expression of EBNA1 or Tat. In addition, co-transfected pTRR1 does not affect the expression of Tat in the presence of absence of 0.03 μM sodium selenite added to the media. β-actin was used as a loading control.