Fig. 1.

Co-immunoprecipitation of selenoprotein mRNAs bound to NSEP1 in human and rat cell lines. Upper parts: RT-PCR detection of mRNA encoding human cytosolic glutathione peroxidase (GPx1) or phospholipid hydroperoxide glutathione peroxidase (GPx4), as indicated in the left margin, from human HeLa cells. Lower parts: RT-PCR detection of mRNA encoding rat GPx1 or GPx4, as indicated in the left margin, from rat McArdle 7777 cells. Intact cells were treated with formaldehyde to crosslink mRNA to associated binding proteins, then lysed and the lysates immunoprecipitated with the antibodies listed below and protein A-sepharose beads; the crosslinking was reversed and the released RNA species identified by RT-PCR. RT-PCR products were detected by ethidium bromide staining of agarose gels. Lane 1, normal rabbit serum; Lane 2, purified rabbit IgG against human NSEP1; Lane 3, rabbit antiserum against human poly (A) binding protein. Lane 4, RT-PCR using total cellular RNA prior to protein A-sepharose bead extractions.