Figure 7. Effects of DN-TonEBP on NaCl-induced TauT and AR expression. ARPE-19 cells transiently transfected with either H₂O or 10 µg of DN-TonEBP were incubated for 8 h with iso-osmolar medium (control, CT) or media containing the additional presence of 100 mM NaCl (Na100). (A) Aldose reductase (AR) and (B) sodium-dependent taurine transporter (TauT) mRNA levels were measured with real-time quantitative PCR (RT-qPCR) as described in the Methods section. The data are the mean ± standard error of the mean (SEM; n=5) and are expressed as gene mRNA levels (in fold stimulation) over the iso-osmolar condition set to 1 for H₂O and a dominant negative form of tonicity enhancer binding protein (DN-TonEBP) following normalization with the appropriate reference genes (YWHAZ, ATP5B, MDH1). Statistical analysis was performed with the conformity t test (#p<0.05; ##p<0.01) that compared the Na100 condition to the iso-osmolar condition, and a paired t test (*p<0.05) as used to compare DN-TonEBP in Na100 to DN-TonEBP in the iso-osmolar condition.