OVERPRODUCTION OF SELENOCYSTEINE TRANSFER-RNA IN CHINESE-HAMSTER OVARY CELLS FOLLOWING TRANSFECTION OF THE MOUSE TRNA([SER]SEC) GENE

Citation
Me. Moustafa et al., OVERPRODUCTION OF SELENOCYSTEINE TRANSFER-RNA IN CHINESE-HAMSTER OVARY CELLS FOLLOWING TRANSFECTION OF THE MOUSE TRNA([SER]SEC) GENE, RNA, 4(11), 1998, pp. 1436-1443
Citations number
33
Categorie Soggetti
Biology
Journal title
RNAACNP
ISSN journal
13558382
Volume
4
Issue
11
Year of publication
1998
Pages
1436 - 1443
Database
ISI
SICI code
1355-8382(1998)4:11<1436:OOSTIC>2.0.ZU;2-#
Abstract
Selenocysteine insertion during selenoprotein biosynthesis begins with the aminoacylation of selenocysteine tRNA([Ser]Sec) with serine, the conversion of the serine moiety to selenocysteine, and the recognition of specific UGA codons within the mRNA. Selenocysteine tRNA([Ser]Sec) exists as two major forms, differing by methylation of the ribose por tion of the nucleotide at the wobble position of the anticodon. The le vels and relative distribution of these two forms of the tRNA are infl uenced by selenium in mammalian cells and tissues. We have generated C hinese hamster ovary cells that exhibit increased levels of tRNA([Ser] Sec) following transfection of the mouse tRNA([Ser]Sec) gene. The leve ls of selenocysteine tRNA([Ser]Sec) in transfectants increased proport ionally to the number of stably integrated copies of the tRNA([Ser]Sec ) gene. Although we were able to generate transfectants overproducing tRNA([Ser]Sec) by as much as tenfold, the additional tRNA was principa lly retained in the unmethylated form. Selenium supplementation could not significantly affect the relative distributions of the two major s elenocysteine tRNA([Ser]Sec) isoacceptors. In addition, increased leve ls of tRNA([Ser]Sec) did not result in measurable alterations in the l evels of selenoproteins, including glutathione peroxidase.