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Selenoproteins and selenocysteine insertion system in the model plant cell system, Chlamydomonas reinhardtii
Author(s) -
Novoselov Sergey V.,
Rao Mahadev,
Onoshko Natalia V.,
Zhi Huijun,
Kryukov Gregory V.,
Xiang Youbin,
Weeks Donald P.,
Hatfield Dolph L.,
Gladyshev Vadim N.
Publication year - 2002
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdf372
Subject(s) - selenocysteine , chlamydomonas reinhardtii , selenoprotein , chlamydomonas , biology , biochemistry , stop codon , genetics , gene , glutathione peroxidase , enzyme , glutathione , cysteine , mutant
Known eukaryotic selenocysteine (Sec)‐containing proteins are animal proteins, whereas selenoproteins have not been found in yeast and plants. Surprisingly, we detected selenoproteins in a member of the plant kingdom, Chlamydomonas reinhardtii , and directly identified two of them as phospholipid hydroperoxide glutathione peroxidase and selenoprotein W homologs. Moreover, a selenocysteyl‐tRNA was isolated that recognized specifically the Sec codon UGA. Subsequent gene cloning and bioinformatics analyses identified eight additional selenoproteins, including methionine‐ S ‐sulfoxide reductase, a selenoprotein specific to Chlamydomonas . Chlamydomonas selenoprotein genes contained selenocysteine insertion sequence (SECIS) elements that were similar, but not identical, to those of animals. These SECIS elements could direct selenoprotein synthesis in mammalian cells, indicating a common origin of plant and animal Sec insertion systems. We found that selenium is required for optimal growth of Chlamydomonas . Finally, evolutionary analyses suggested that selenoproteins present in Chlamydomonas and animals evolved early, and were independently lost in land plants, yeast and some animals.