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From Stop to Go: role of the specialized elongation factor eEFSec in recoding UGA for selenocysteine incorporation (566.3)
Author(s) -
Dubey Aditi,
Szwed Angelia,
Copeland Paul
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.566.3
Subject(s) - selenocysteine , elongation factor , stop codon , ef tu , ribosome , transfer rna , release factor , eukaryotic translation elongation factor 1 alpha 1 , biology , context (archaeology) , genetics , genetic code , amino acid , microbiology and biotechnology , chemistry , computational biology , gene , biochemistry , rna , paleontology , cysteine , enzyme
The incorporation of the 21 st amino acid selenocysteine (Sec) into proteins requires the recoding of an in‐frame UGA, usually a termination codon, to a Sec codon. While it is known that Sec incorporation utilizes a dedicated set of cis and trans acting factors to synthesize these selenoproteins, how this recoding event takes place at the elongating ribosome is unknown. eEFSec, the selenocystyl‐specific elongation factor, is a specialized elongation factor that bears structural resemblance to the canonical elongation factor eEF1A. However, eEFSec recognizes only one species of tRNA, the Sec‐tRNA Sec , and delivers it to the ribosome only in response to an in‐frame UGA in the appropriate context. To elucidate eEFSec’s role in recoding UGA to Sec, we have conducted a systematic analysis of all four eEFSec domains using chimeric eEFSec/eEF1A proteins in our recently developed eEFSec‐dependent assay. In addition, through immunoprecipitation in various cell and tissue extracts, we have identified eEFSec‐specific interacting proteins that may act as regulatory elements of this specialized elongation cycle. Altogether, our results shed light on the molecular and cellular mechanism of recoding a Stop codon to selenocysteine in eukaryotes. Grant Funding Source : Supported by NIH Grant GM077073 to PRC