A conserved role for the ESCRT membrane budding complex in LINE retrotransposition.
A conserved role for the ESCRT membrane budding complex in LINE retrotransposition.
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DOI：
10.1371/journal.pgen.1006837
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发表时间：
2017-06
期刊：
影响因子：
4.5
通讯作者：
Han JS
中科院分区：
文献类型：
--
作者：
Horn AV;Celic I;Dong C;Martirosyan I;Han JS
长散布核元件-1（LINE-1 s，或L1 s）是一个活跃的逆转录转座因子家族，持续突变哺乳动物基因组。尽管L1对哺乳动物基因组进化有很大贡献，但我们不知道活跃的L1颗粒（反转录过程中的颗粒）位于细胞中的何处，也不知道它们如何向细胞核（L1反转录的位点）移动。使用酵母模型的LINE反转录转座，我们确定ESCRT（内体分选复合物运输所需的）作为一个关键的复杂的LINE反转录转座，并验证了这种相互作用是保守的人L1。ESCRT通过晚期结构域基序与L1相互作用，这种相互作用促进L1复制。L1/ESCRT相互作用的丧失不会损害RNP形成或酶活性，但会导致逆转录转座的丧失和细胞核中L1内切核酸酶活性的降低。这项研究强调了ESCRT复杂的L1生命周期的重要性，并提出了一个不寻常的模式L1 RNP贩运。长散布核元件（LINEs）是一类逆转录转座因子，可使哺乳动物基因组发生突变。LINE在人类基因组中非常成功，繁殖到超过80万个拷贝。LINE编码的复制机制也被其他反转录转座子使用，并且总共负责产生超过1/3的人类DNA序列。为了复制，LINE mRNA与其蛋白质形成核糖核蛋白颗粒（RNP）。这种RNP最终进入细胞核，将其自身的cDNA拷贝整合到染色体中。RNP形成和成功整合之间的事件很难研究，而且在很大程度上是未知的。在这里，我们表明，ESCRT复合物在酵母和人类的LINE逆转录转座中起着保守的作用。ESCRT是一种膜出芽复合物，参与细胞运输和膜出芽/融合。我们的研究结果意味着，膜发挥LINE复制的一个组成部分，和ESCRT可能需要RNP向核贩运。
Long interspersed nuclear element-1s (LINE-1s, or L1s) are an active family of retrotransposable elements that continue to mutate mammalian genomes. Despite the large contribution of L1 to mammalian genome evolution, we do not know where active L1 particles (particles in the process of retrotransposition) are located in the cell, or how they move towards the nucleus, the site of L1 reverse transcription. Using a yeast model of LINE retrotransposition, we identified ESCRT (endosomal sorting complex required for transport) as a critical complex for LINE retrotransposition, and verified that this interaction is conserved for human L1. ESCRT interacts with L1 via a late domain motif, and this interaction facilitates L1 replication. Loss of the L1/ESCRT interaction does not impair RNP formation or enzymatic activity, but leads to loss of retrotransposition and reduced L1 endonuclease activity in the nucleus. This study highlights the importance of the ESCRT complex in the L1 life cycle and suggests an unusual mode for L1 RNP trafficking. Long interspersed nuclear elements (LINEs) are a class of retrotransposable elements that mutate mammalian genomes. LINEs have been highly successful in the human genome, multiplying to over 800,000 copies. The LINE-encoded replication machinery is also used by other retrotransposons, and in total, has been responsible for the generation of over 1/3 of human DNA sequence. To replicate, a LINE mRNA forms a ribonucleoprotein particle (RNP) with its proteins. This RNP eventually enters the nucleus to integrate a cDNA copy of itself into chromosomes. The events between RNP formation and successful integration are difficult to study and largely unknown. Here we show that the ESCRT complex plays a conserved role in LINE retrotransposition in both yeast and humans. ESCRT is a membrane budding complex involved in cellular trafficking and membrane budding/fusion. Our results imply that membranes play an integral part of LINE replication, and ESCRT may be required for RNP trafficking towards the nucleus.