Novel family of human transposable elements formed due to fusion of the first exon of gene MAST2 with retrotransposon SVA
Novel family of human transposable elements formed due to fusion of the first exon of gene MAST2 with retrotransposon SVA
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DOI：
10.1134/s0006297909120153
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发表时间：
2009-12-01
影响因子：
2.8
通讯作者：
Buzdin, A. A.
中科院分区：
文献类型：
--
作者：
Bantysh, O. B.;Buzdin, A. A.
我们鉴定了一个新的人类特异性转座元件家族，该家族由包含基因 MAST2 的第一个外显子和逆转录转座子 SVA 的 CpG 岛的融合副本组成。我们提出了一种称为 CpG-SVA 的家族形成机制，包括通过 SVA 插入片段进行 5'-转导。在人类和黑猩猩祖先谱系出现分歧后，逆转录转座子SVA已以有义方向插入到基因MAST2的第一个内含子中。由于由 MAST2 启动子驱动的异常 RNA 的剪接，但最终使用 SVA 多腺苷酸化信号进行加工，MAST2 的第一个外显子已与 SVA 反转录转座子的剪接 3' 末端片段融合。上述祖先CpG-SVA元件由于其自身拷贝的逆转座而形成了一个新的家族，在人类基因组中由76个成员代表。 MAST2 CpG 岛的募集很可能对混合逆转录转座子有益，因为它可以显着增加逆转录转座频率。此外，我们还发现人 L1 逆转录酶在新生 cDNA 第一链的 3' 末端添加了一个额外的胞嘧啶残基。
We identified a novel human-specific family of transposable elements that consists of fused copies of the CpG-island containing the first exon of gene MAST2 and retrotransposon SVA. We propose a mechanism for the formation of this family termed CpG-SVA, comprising 5'-transduction by an SVA insert. After the divergence of human and chimpanzee ancestor lineages, retrotransposon SVA has inserted into the first intron of gene MAST2 in the sense orientation. Due to splicing of an aberrant RNA driven by MAST2 promoter, but terminally processed using SVA polyadenylation signal, the first exon of MAST2 has fused to a spliced 3'-terminal fragment of SVA retrotransposon. The above ancestor CpG-SVA element due to retrotranspositions of its own copies has formed a novel family represented in the human genome by 76 members. Recruitment of a MAST2 CpG island was most likely beneficial to the hybrid retrotransposons because it could significantly increase retrotransposition frequency. Also, we show that human L1 reverse transcriptase adds an extra cytosine residue to the 3' terminus of the nascent first strand of cDNA.