FIGURE 1.

The antibiotics Dox, Cp, or G418 differentially affect Sec insertion and selenoprotein expression in EMT6 cells. EMT6 cells were grown in the presence and absence of Dox, Cp, and G418, and the levels of selenoproteins were assessed. A, determination of selenoprotein levels by ⁷⁵Se labeling and Western blotting. Cells were cultured in the presence or absence of Dox (10 or 20 μg/ml), Cp (25 or 50 μg/ml), or G418 (100 or 200 μg/ml) and labeled with ⁷⁵Se (15 μCi/well), protein extracts were prepared and electrophoresed, labeled selenoproteins were identified by autoradiography (upper panel), and TR1, GPx1, and GPx4 levels were further assessed by Western blotting (four lower panels). GAPDH is shown as a loading control. B, quantification of ⁷⁵Se labeling and expression of TR1, GPx1, and GPx4. Values shown are the relative intensities of ⁷⁵Se labeling or Western blot signals of proteins in treated cells when compared with those in cells grown in the absence of antibiotics. Values are the means ± S.D. of three independent experiments. Experimental details are given under ”Experimental Procedures.“