Suoniemi A, Tanskanen J, Schulman A H
Institute of Biotechnology, University of Helsinki, Finland.
Plant J. 1998 Mar;13(5):699-705. doi: 10.1046/j.1365-313x.1998.00071.x.
Retrotransposons propagate via an RNA intermediate which is then reverse-transcribed and packaged into virus-like particles. They are either copia- or gypsy-like in coding domain order and sequence similarity, the gypsy-like elements sharing their organization with the retroviruses but lacking retroviral envelope domains. Copia-like retrotransposons, or at least their reverse transcriptase domains, appear broadly distributed in higher plants, but gypsy-like elements have been reported only for scattered species. The authors have exploited the difference in domain order between these groups to amplify and clone segments bridging the reverse transcriptase-integrase region of specifically gypsy-like retrotransposons. Species representative of the diversity of higher plants yielded products whose sequences establish that gypsy-like transposons are dispersed throughout the plant genomes. This class of plant elements has been named romani retrotransposons. The presence of both types ubiquitously in the fungi, plants and animals support their existence as ancient distinct lineages and subsequent, vertical radiation.
逆转录转座子通过RNA中间体进行传播，该中间体随后被逆转录并包装成病毒样颗粒。根据编码域顺序和序列相似性，它们要么属于类copia型，要么属于类gypsy型，类gypsy元件与逆转录病毒具有相同的组织结构，但缺乏逆转录病毒包膜结构域。类copia逆转录转座子，或至少其逆转录酶结构域，在高等植物中广泛分布，但仅在少数分散的物种中报道过类gypsy元件。作者利用了这两类转座子在结构域顺序上的差异，扩增并克隆了连接特定类gypsy逆转录转座子逆转录酶-整合酶区域的片段。代表高等植物多样性的物种产生的产物序列表明，类gypsy转座子分散在整个植物基因组中。这类植物元件被命名为romani逆转录转座子。这两种类型在真菌、植物和动物中普遍存在，这支持了它们作为古老的不同谱系以及随后垂直辐射的存在。
