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Decoding apparatus for eukaryotic selenocysteine insertion
Author(s) -
Tujebajeva Rosa M,
Copeland Paul R,
Xu XueMing,
Carlson Bradley A,
Harney John W,
Driscoll Donna M,
Hatfield Dolph L,
Berry Marla J
Publication year - 2000
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kvd033
Subject(s) - selenocysteine , elongation factor , selenoprotein , biology , transfer rna , insertion sequence , genetics , microbiology and biotechnology , biochemistry , rna , ribosome , gene , genome , transposable element , glutathione , glutathione peroxidase , cysteine , enzyme
Decoding UGA as selenocysteine requires a unique tRNA, a specialized elongation factor, and specific secondary structures in the mRNA, termed SECIS elements. Eukaryotic SECIS elements are found in the 3′ untranslated region of selenoprotein mRNAs while those in prokaryotes occur immediately downstream of UGA. Consequently, a single eukaryotic SECIS element can serve multiple UGA codons, whereas prokaryotic SECIS elements only function for the adjacent UGA, suggesting distinct mechanisms for recoding in the two kingdoms. We have identified and characterized the first eukaryotic selenocysteyl‐tRNA‐specific elongation factor. This factor forms a complex with mammalian SECIS binding protein 2, and these two components function together in selenocysteine incorporation in mammalian cells. Expression of the two functional domains of the bacterial elongation factor–SECIS binding protein as two separate proteins in eukaryotes suggests a mechanism for rapid exchange of charged for uncharged selenocysteyl‐tRNA–elongation factor complex, allowing a single SECIS element to serve multiple UGA codons.