Castellano Sergi, Novoselov Sergey V, Kryukov Gregory V, Lescure Alain, Blanco Enrique, Krol Alain, Gladyshev Vadim N, Guigó Roderic
Grup de Recerca en Informàtica Biomèdica, Institut Municipal d'Investigació Mèdica, Universitat Pompeu Fabra, Dr. Aiguader 80, 08003 Barcelona, Catalonia, Spain.
EMBO Rep. 2004 Jan;5(1):71-7. doi: 10.1038/sj.embor.7400036.
While the genome sequence and gene content are available for an increasing number of organisms, eukaryotic selenoproteins remain poorly characterized. The dual role of the UGA codon confounds the identification of novel selenoprotein genes. Here, we describe a comparative genomics approach that relies on the genome-wide prediction of genes with in-frame TGA codons, and the subsequent comparison of predictions from different genomes, wherein conservation in regions flanking the TGA codon suggests selenocysteine coding function. Application of this method to human and fugu genomes identified a novel selenoprotein family, named SelU, in the puffer fish. The selenocysteine-containing form also occurred in other fish, chicken, sea urchin, green algae and diatoms. In contrast, mammals, worms and land plants contained cysteine homologues. We demonstrated selenium incorporation into chicken SelU and characterized the SelU expression pattern in zebrafish embryos. Our data indicate a scattered evolutionary distribution of selenoproteins in eukaryotes, and suggest that, contrary to the picture emerging from data available so far, other taxa-specific selenoproteins probably exist.
虽然越来越多生物体的基因组序列和基因内容已为人所知，但真核生物中的硒蛋白仍然鲜为人知。UGA密码子的双重作用使得新型硒蛋白基因的鉴定变得复杂。在此，我们描述了一种比较基因组学方法，该方法依赖于对含有读框内TGA密码子的基因进行全基因组预测，以及随后对不同基因组预测结果的比较，其中TGA密码子侧翼区域的保守性表明了硒代半胱氨酸的编码功能。将该方法应用于人类和河豚基因组，在河豚中鉴定出了一个名为SelU的新型硒蛋白家族。含硒代半胱氨酸的形式也存在于其他鱼类、鸡、海胆、绿藻和硅藻中。相比之下，哺乳动物、蠕虫和陆地植物含有半胱氨酸同源物。我们证明了硒可掺入鸡的SelU中，并对斑马鱼胚胎中SelU的表达模式进行了表征。我们的数据表明硒蛋白在真核生物中的进化分布是分散的，并表明，与目前可得数据所呈现的情况相反，可能还存在其他特定分类群的硒蛋白。
