Vavilov Institute of General Genetics, Russian Academy of Sciences Moscow, Russia.
Front Genet. 2013 Apr 26;4:63. doi: 10.3389/fgene.2013.00063. eCollection 2013.
The molecular mechanisms of the transposition of non-long terminal repeat (non-LTR) retrotransposons are not well understood; the key questions of how the 3'-ends of cDNA copies integrate and how site-specific integration occurs remain unresolved. Integration depends on properties of the endonuclease (EN) domain of retrotransposons. Using the EN domain of the Drosophila R2 retrotransposon as a model for other, closely related non-LTR retrotransposons, we investigated the EN domain and found that it resembles archaeal Holliday-junction resolvases. We suggest that these non-LTR retrotransposons are co-transcribed with the host transcript. Combined with the proposed resolvase activity of the EN domain, this model yields a novel mechanism for site-specific retrotransposition within this class of retrotransposons, with resolution proceeding via a Holliday junction intermediate.
非长末端重复（non-LTR）反转录转座子的转座分子机制尚不清楚；cDNA 拷贝 3'-末端如何整合以及如何发生特异性整合等关键问题仍未解决。整合取决于反转录转座子内切酶（EN）结构域的特性。我们使用果蝇 R2 反转录转座子的 EN 结构域作为其他密切相关的非 LTR 反转录转座子的模型，研究了 EN 结构域，发现它类似于古细菌 Holliday 连接体解旋酶。我们认为这些非 LTR 反转录转座子与宿主转录本一起转录。结合 EN 结构域的拟议解旋酶活性，该模型为该类反转录转座子中的特异性反转录转座提供了一种新的机制，通过 Holliday 连接中间体进行分辨率。
