Adaptive evolution in LINE-1 retrotransposons
Adaptive evolution in LINE-1 retrotransposons
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DOI：
10.1093/oxfordjournals.molbev.a003765
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发表时间：
2001-12-01
影响因子：
10.7
通讯作者：
Furano, AV
中科院分区：
文献类型：
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作者：
Boissinot, SP;Furano, AV
我们追踪了LINE-1（L1）逆转录转座子的活性谱系的序列进化，这与人类进化的2500万年相似。五个主要家族（L1 PA 5、L1 PA 4、L1 PA 3B、L1 PA 2和L1 PA 1）的元件作为一个单一的谱系相互继承。我们发现，第一个开放阅读框（ORFI）的一部分有一个更高的非同义（氨基酸置换）取代比同义取代的祖先L1 PA 5通过L1 PA 3B家族的演变过程中。该片段编码ORFI蛋白（ORFIP）的蛋白质-蛋白质相互作用结构域的卷曲螺旋区。对这些变化的统计分析表明，正选择作用于该区域。相反，卷曲螺旋段几乎没有改变的L1 PA 3B的演变过程中，目前的L1 PA 1家庭。因此，盘绕的线圈段上的选择性压力随时间变化。我们认为，快速的氨基酸替换率在卷曲螺旋段反映了适应L1无论是一个不断变化的基因组环境或宿主阻遏因子。相反，第二开放阅读框和第一开放阅读框的核酸结合结构域非常保守，证明了作用于这些区域的强纯化选择。
We traced the sequence evolution of the active lineage of LINE-1 (L1) retrotransposons over the last similar to 25 Myr of human evolution. Five major families (L1PA5, L1PA4, L1PA3B, L1PA2, and L1PA1) of elements have succeeded each other as a single lineage. We found that part of the first open-reading frame (ORFI) had a higher rate of nonsynonymous (amino acid replacement) substitution than synonymous substitution during the evolution of the ancestral L1PA5 through the L1PA3B families. This segment encodes the coiled coil region of the protein-protein interaction domain of the ORFI protein (ORFIp). Statistical analysis of these changes indicates that positive selection had been acting on this region. In contrast, the coiled coil segment hardly changed during the evolution of the L1PA3B to the present L1PA1 family. Therefore, selective pressure on the coiled coil segment has changed over time. We suggest that the fast rate of amino acid replacement in the coiled coil segment reflects the adaptation of L1 either to a changing genomic environment or to host repression factors. In contrast, the second open-reading frame and the nucleic acid-binding domain of the first open-reading frame are extremely well conserved, attesting to the strong purifying selection acting on these regions.