Zisupton-A Novel Superfamily of DNA Transposable Elements Recently Active in Fish
Zisupton-A Novel Superfamily of DNA Transposable Elements Recently Active in Fish
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DOI：
10.1093/molbev/msr208
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发表时间：
2012-02-01
影响因子：
10.7
通讯作者：
Volff, Jean-Nicolas
中科院分区：
文献类型：
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作者：
Boehne, Astrid;Zhou, Qingchun;Volff, Jean-Nicolas
转座元件是广泛存在的可移动的DNA序列，能够整合到基因组中的新位置。通过转座和重组，它们极大地促进了基因组的可塑性和进化。它们还可以调节基因表达，并为新基因功能的进化提供调控和编码序列(CDS)。我们在斑剑鱼Y染色体上发现了一个新的DNA转座子超家族。该片段长度为11kb，携带24个外显子的单个CDS。该蛋白的N端部分在所有受试的成体组织中都有表达，含有几个核酸和蛋白质结合域，可能对应于一种迄今为止在转座子中尚未描述的新型转座酶/整合酶。此外，睾丸特异的剪接异构体编码一个C-末端的Ulp1相扑酶结构域，这表明在相扑和/或泛素小肽介导的翻译后蛋白质修饰中具有功能。因此，这种元件被称为Zisupton，即锌指相扑蛋白转座子。除了Y染色体序列外，在鸭嘴兽基因组中还发现了另外五个非常相似的拷贝。所有的拷贝都以99个碱基保守的亚端反向重复序列为界，两侧是拷贝特异的8-nT靶点重复序列，反映了它们在基因组不同位置的整合。Zisupton元件在不同的节肢动物中插入到不同的基因组位置，也在不同的种群中插入。相关物种和种群之间的这种插入多态表明相对较新的转座活性，物种之间高度的核苷酸同源性表明可能存在水平基因转移。Zisupton序列在其他鱼类中也被检测到，在尾索动物、头索动物和半角动物以及更远的生物中也被检测到，例如担子菌真菌、丝状褐藻和绿藻。来自齐苏普顿的核基因的可能例子已经被确定。总之，我们的分析揭示了一个新的DNA转座子超家族，它在鱼类和其他生物的基因组多样性和进化创新中具有潜在的作用。
Transposable elements are widespread mobile DNA sequences able to integrate into new locations within genomes. Through transposition and recombination, they significantly contribute to genome plasticity and evolution. They can also regulate gene expression and provide regulatory and coding sequences (CDSs) for the evolution of novel gene functions. We have identified a new superfamily of DNA transposon on the Y chromosome of the platyfish Xiphophorus maculatus. This element is 11 kb in length and carries a single CDS of 24 exons. The N-terminal part of the putative protein, which is expressed in all adult tissues tested, contains several nucleic acid- and protein-binding domains and might correspond to a novel type of transposase/integrase not described so far in any transposon. In addition, a testis-specific splice isoform encodes a C-terminal Ulp1 SUMO protease domain, suggesting a function in posttranslational protein modification mediated by SUMO and/or ubiquitin small peptides. Accordingly, this element was called Zisupton, for Zinc finger SUMO protease transposon. Beside the Y-chromosomal sequence, five other very similar copies were identified in the platyfish genome. All copies are delimited by 99-bp conserved subterminal inverted repeats and flanked by copy-specific 8-nt target site duplications reflecting their integration at different positions in the genome. Zisupton elements are inserted at different genomic locations in different poeciliid species but also in different populations of X. maculatus. Such insertion polymorphisms between related species and populations indicate relatively recent transposition activity, with a high degree of nucleotide identity between species suggesting possible implication of horizontal gene transfer. Zisupton sequences were detected in other fish species, in urochordates, cephalochordates, and hemichordates as well as in more distant organisms, such as basidiomycete fungi, filamentous brown algae, and green algae. Possible examples of nuclear genes derived from Zisupton have been identified. To conclude, our analysis has uncovered a new superfamily of DNA transposons with potential roles in genome diversity and evolutionary innovation in fish and other organisms.