EXPRESSION OF THE GLUTATHIONE-PEROXIDASE GENE LACKING ITS 3'-UNTRANSLATED REGION

In order to investigate the expression of human cellular glutathione p eroxidase (GPx), we mutated the gene encoding GPx by deleting either t he 5' or 3' untranslated region (utr), subcloned the deleted fragments into plasmid pSVL followed by transfection into COS-7 cells and measu red the amount of GPx expressed. When the 5' utr of the gene was delet ed, GPx was not expressed. However, the deletion of the 3' utr resulte d in some expression of GPx. Deletion of the poly A region of the GPx gene resulted in the expression of GPx but the level was lower than th at of full-length cGPx. The complete deletion of the 3' utr resulted i n a half of the expression of the poly A deletion mutant. Thus, the ex pression of GPx increased according to the length of the 3' utr. These results suggest that the GPx gene carrying one SECIS on 5' utr (FEBS Lett. 312(1992)10-14) is essential for GPx expression. SECIS on 3' utr might not play a key role of GPx expression. Expression of GPx by COS -7 cells was not observed when a plasmid harboring an antisense gene w as transfected.