Template jumping by a LINE reverse transcriptase has created a SINE-like 5S rRNA retropseudogene in Dictyostelium
Template jumping by a LINE reverse transcriptase has created a SINE-like 5S rRNA retropseudogene in Dictyostelium
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DOI：
10.1007/s00438-003-0961-9
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发表时间：
2004-02
影响因子：
3.1
通讯作者：
K. Szafranski;T. Dingermann;G. Glöckner;T. Winckler
中科院分区：
文献类型：
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作者：
K. Szafranski;T. Dingermann;G. Glöckner;T. Winckler
短散在核元件（Short interspersed nuclear elements，西内斯）是一种非自主的逆转录元件，它模仿所谓的长散在核元件（Long interspersed nuclear elements，LINES）的3′端，以确保它们通过自主LINES编码的蛋白质进行繁殖。盘基网柄藻基因组包含一个LINE样逆转录转座子家族，该家族特异性靶向tRNA基因进行整合（TRE元件）。我们在这里描述了一个逆转录转座核糖体5S RNA假基因在D。盘状体基因组，在其3′端含有来自TRE的3′端的8-bp序列和多聚腺嘌呤尾。r5 S“retropeptidogene”的侧翼是TREs特有的靶位点重复，并插入tRNA基因的上游，就像典型的TRE一样。D. discoideumr 5S逆转录酶基因具有SINE的结构特征，但未被扩增，可能是由于其初始逆转录转座时发生的5′-截短。这一发现D. discoideumr 5S retropylidogene的研究表明，如果LINE编码的逆转录酶与LINE RNA分离并跳转到其他细胞RNA-特别是RNA聚合酶III转录的基因-以产生连续的混合cDNA，则可以在LINE转录物的逆转录过程中从头产生西内斯。
Short interspersed nuclear elements (SINEs) are non-autonomous retroelements that mimic the 3′ ends of so-called long interspersed nuclear elements (LINEs) to ensure their propagation by proteins encoded by autonomous LINEs. TheDictyostelium discoideumgenome contains a family of LINE-like retrotransposons that specifically target tRNA genes for integration (TRE elements). We describe here a retrotransposed ribosomal 5S RNA pseudogene in theD. discoideumgenome that contains at its 3′ end an 8-bp sequence derived from the 3′ end of a TRE and a polyadenine tail. The r5S “retropseudogene” is flanked by target-site duplications that are characteristic for TREs, and is inserted upstream of a tRNA gene, just like a typical TRE. TheD. discoideumr5S retropseudogene has structural features of a SINE, but has not been amplified, probably due to the 5′-truncation that occurred upon its initial retrotransposition. The discovery of thisD. discoideumr5S retropseudogene reveals that SINEs can be created de novo during reverse transcription of LINE transcripts, if the LINE-encoded reverse transcriptase dissociates from the LINE RNA and jumps to other cellular RNAs—particularly genes transcribed by RNA polymerase III—to create continuous mixed cDNAs.