FIGURE 7.

SelW promoter is not activated by selenium in differentiating C2C12 cells. A, real time PCR analysis of SelW gene expression in different culture media after induction of C2C12 differentiation. Expression level of SelW mRNA in D0 was arbitrarily set at 1. Data are represented as means ± S.D. of three independent experiments performed in triplicate. B, phase-contrast microscopic images of differentiating C2C12 cells cultured under the experimental conditions at D3 shown in A. Bar, 100 μm. C, relative expression of SelW mRNA in culture media supplemented with different levels of sodium selenite. The data are represented as means ± S.D. of three independent experiments performed in triplicate. D, real time PCR crossing point values of SelW and Hprt1 mRNAs shown in C. The values are expressed as means ± S.D. E, SelW promoter activity and MyoD expression in differentiating C2C12 cells in different culture media. C2C12 cells were transfected with −973SelW/Luc and pRL-TK, maintained in GM up to ∼100% confluence, followed by cultivation in culture media without or with selenium for 1 day. SelW gene promoter activity was measured and normalized to the Renilla activity of pRL-TK. MyoD expression was analyzed by Western blotting. F, phase-contrast microscopic images of differentiating C2C12 cells for 5 days under the same medium conditions shown in E. Panel a, DMEM with 2% HS; panel b, DMEM; panel c, DMEM with 30 nm sodium selenite. Bar, 100 μm.