Fig. 5.

Overexpression of Sec-TRs but not Cys-TRs supports increased cell viability in response to low levels of oxidative stress. (A and C) C10 cells were transfected with the indicated constructs, treated overnight with subcytotoxic concentrations of MD, and oxidant production was evaluated by monitoring DCF fluorescence. Expression of any isoform of TR1 or TR2 had no statistically significant effect on the relative intensity of DCF fluorescence by 24 h. (B and D) C10 cells were transfected with the indicated expression vectors and cell viability after 24 h treatment with MD was quantified (*p<0.05, WT-TR1 compared to pcDNA). (E and F) C10 cells were transfected with the indicated TR expression vectors as in B and D, but in this instance with or without expression vectors for the cognate TRX. Cells were treated with the indicated concentrations of MD and after 24 h cell viability was quantified. Note that expression of TRX1 or TRX2 alone, or with the cognate TR, did not improve viability over that observed with expression of Sec-TR1 or Sec-TR2 alone.