Szmulewicz M N, Novick G E, Herrera R J
Department of Biological Sciences, Florida International University, Miami 33199, USA.
Electrophoresis. 1998 Jun;19(8-9):1260-4. doi: 10.1002/elps.1150190806.
Alu elements are a family of short interspersed repetitive elements (SINEs) found exclusively in primates. These elements are around 300 base pairs long, are found in excess of one million copies per diploid genome, and are dispersed throughout the human genome. Alu elements are scattered by a mechanism called "retrotransposition". Three independent steps are involved in retrotransposition: transcription of the Alu repetitive element, reverse transcription of the Alu RNA and integration of the Alu cDNA. The fact that Alu elements retrotranspose so readily suggests that they have a myriad of effects on the genome, mostly by inactivating genes or altering their function. These characteristics of Alu repetitive elements point to these repetitive DNA fragments as a major driving force for evolution. In addition, Alu elements are known to adopt diverse functions depending on the context of the surrounding genetic material into which they insert. In this article, we review some of the evidence that demonstrates the functional significance of Alu repeats.
Alu元件是一类短散在重复元件（SINEs），仅在灵长类动物中发现。这些元件长度约为300个碱基对，在每个二倍体基因组中拷贝数超过一百万个，并且分散在整个人类基因组中。Alu元件通过一种称为“逆转座”的机制进行散布。逆转座涉及三个独立步骤：Alu重复元件的转录、Alu RNA的逆转录以及Alu cDNA的整合。Alu元件如此容易发生逆转座这一事实表明它们对基因组有无数影响，主要是通过使基因失活或改变其功能。Alu重复元件的这些特征表明这些重复DNA片段是进化的主要驱动力。此外，已知Alu元件根据它们插入的周围遗传物质的背景发挥多种功能。在本文中，我们综述了一些证明Alu重复序列功能重要性的证据。
