Newly sequenced eRF1s from ciliates: the diversity of stop codon usage and the molecular surfaces that are important for stop codon interactions
Newly sequenced eRF1s from ciliates: the diversity of stop codon usage and the molecular surfaces that are important for stop codon interactions
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DOI：
10.1016/j.gene.2004.11.046
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发表时间：
2005-02-14
期刊：
影响因子：
3.5
通讯作者：
Harumoto, T
中科院分区：
文献类型：
--
作者：
Kim, OTP;Yura, K;Harumoto, T
一些纤毛虫核基因的遗传密码与其他生物不同，通常被指定为终止密码子的UGA、UAG和UAA密码子。在一些纤毛虫物种中，通用终止密码子UAA和UAG编码谷氨酰胺。在其他一些纤毛虫中，通用终止密码子UGA似乎被翻译为半胱氨酸或色氨酸。真核细胞释放因子1（eRF1）是终止密码子识别的关键蛋白，在纤毛虫终止密码子重分配中起重要作用。我们已经克隆，测序，并分析了eRF1的cDNA从四个纤毛虫物种的三个不同的类：核壳虫（Loxodes striatus），异毛虫（Blepharisma musculus），和Litostomatea（Didinium nasutum，Dileptus margaritifer）。这些eRF1s的系统发育分析支持的假设，在纤毛虫的遗传密码已经独立偏离了几次从通用的遗传密码，不同的纤毛虫eRF1s可能经历了不同的过程，以改变密码子的特异性。使用计算方法，我们还建议在纤毛类eRF1s的终止密码子识别的重要的eRF1s的表面上的区域。(c)2004 Elsevier B.V.保留所有权利。
The genetic code of nuclear genes in some ciliates was found to differ from that of other organisms in the assignment of UGA, UAG, and UAA codons, which are normally assigned as stop codons. In some ciliate species, the universal stop codons UAA and UAG instead encode glutamine. In some other ciliates, the universal stop codon UGA appears to be translated as cysteine or tryptophan. Eukaryotic release factor 1 (eRF1) is a key protein, in stop codon recognition, thus, the protein is believed to play an important role in the stop codon reassignment in ciliates. We have cloned, sequenced, and analyzed the cDNA of eRF1 from four ciliate species of three different classes: Karyorelictea (Loxodes striatus), Heterotrichea (Blepharisma musculus), and Litostomatea (Didinium nasutum, Dileptus margaritifer). Phylogenetic analysis of these eRF1s supports the hypothesis that the genetic code in ciliates has deviated independently several times from the universal genetic code, and that different ciliate eRF1s may have undergone different processes to change the codon specificity. Using computational methods, we have also suggested areas on the surface of eRF1s that are important for stop codon recognition in ciliate eRF1s. (c) 2004 Elsevier B.V. All rights reserved.