Selenoproteins and selenocysteine insertion system in the model plant cell system, Chlamydomonas reinhardtii
Selenoproteins and selenocysteine insertion system in the model plant cell system, Chlamydomonas reinhardtii
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DOI：
10.1093/emboj/cdf372
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发表时间：
2002-07-15
期刊：
影响因子：
11.4
通讯作者：
Gladyshev, VN
中科院分区：
文献类型：
--
作者：
Novoselov, SV;Rao, M;Gladyshev, VN
已知的真核含硒半胱氨酸（Sec）的蛋白质是动物蛋白，而硒蛋白尚未在酵母和植物中发现。令人惊讶的是，我们在莱茵衣藻（Chlamydomonas reinhardtii）中检测到硒蛋白，并直接鉴定出其中两种为磷脂氢过氧化物谷胱甘肽过氧化物酶和硒蛋白W同源物。此外，还分离出一个硒代半胱氨酸- trna，该trna特异性识别Sec密码子UGA。随后的基因克隆和生物信息学分析确定了8个额外的硒蛋白，包括甲硫氨酸-s -亚砜还原酶，这是衣藻特有的硒蛋白。衣藻硒蛋白基因含有与动物相似但不完全相同的硒半胱氨酸插入序列（SECIS）元件。这些SECIS元件可以指导哺乳动物细胞中硒蛋白的合成，表明植物和动物的SECIS插入系统有共同的起源。我们发现硒是衣藻最佳生长所必需的。最后，进化分析表明，硒蛋白存在于衣藻和动物中，进化较早，在陆地植物、酵母和一些动物中独立丢失。
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.