Self-synthesizing DNA transposons in eukaryotes
Self-synthesizing DNA transposons in eukaryotes
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DOI：
10.1073/pnas.0600833103
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发表时间：
2006-03-21
影响因子：
11.1
通讯作者：
Jurka, J
中科院分区：
文献类型：
--
作者：
Kapitonov, VV;Jurka, J
真核生物含有许多能够在宿主基因组中进行寄生虫样增殖的转座或移动的元件。真核生物中所有已知的转座因子都属于两种类型：反转录转座子和DNA转座子。在这里，我们报告了一个以前没有特征的DNA转座子称为Polintons填充原生生物，真菌和动物，包括内阿米巴，大豆锈病，水螅，海葵，线虫，果蝇，甲虫，海胆，海鞘，鱼，蜥蜴，青蛙和鸡的基因组。来自所有这些物种的Polintons的特征在于其转座所必需的一组独特的蛋白质，包括蛋白质引发的DNA聚合酶13、逆转录病毒整合酶、半胱氨酸蛋白酶和ATP酶。此外，Polintons的特征在于6-bp靶位点重复、数百个核苷酸长的末端反向重复序列以及5 '-AG和TC-3'末端。类似于已知的转座因子，Polintons以自主和非自主的形式存在。我们的数据表明，Polintons是从至少10亿年前获得逆转录病毒整合酶的线性质粒进化而来的。根据本文提出的Polinton转座模型，从基因组中切下的Polinton DNA分子作为模板，通过Polinton编码的DNA聚合酶在染色体外合成其双链DNA拷贝，并通过其整合酶插入基因组中。
Eukaryotes contain numerous transposable or mobile elements capable of parasite-like proliferation in the host genome. All known transposable elements in eukaryotes belong to two types: retrotransposons and DNA transposons. Here we report a previously uncharacterized class of DNA transposons called Polintons that populate genomes of protists, fungi, and animals, including entamoeba, soybean rust, hydra, sea anemone, nematodes, fruit flies, beetle, sea urchin, sea squirt, fish, lizard, frog, and chicken. Polintons from all these species are characterized by a unique set of proteins necessary for their transposition, including a protein-primed DNA polymerase 13, retroviral integrase, cysteine protease, and ATPase. In addition, Polintons are characterized by 6-bp target site duplications, terminal-inverted repeats that are several hundred nuclecitides long, and 5'-AG and TC-3' termini. Analogously to known transposable elements, Polintons exist as autonomous and nonautonomous elements. Our data suggest that Polintons have evolved from a linear plasmid that acquired a retroviral integrase at least 1 billion years ago. According to the model of Polinton transposition proposed here, a Polinton DNA molecule excised from the genome serves as a template for extrachromosomal synthesis of its double-stranded DNA copy by the Polinton-encoded DNA polymerase and is inserted back into genome by its integrase.