Greenwood A D, Leib-Mösch C, Seifarth W
Technical University Munich, Institute of Virology, Munich, Germany.
Cytogenet Genome Res. 2005;110(1-4):553-8. doi: 10.1159/000084988.
Non-LTR retrotransposons are a diverse and taxonomically widely dispersed group of retroelements that can be divided into at least 14 distinguishable clades. Basal metazoans have not been examined in great detail for their retrotransposon content. In order to screen for the presence of reverse transcriptase (RT) related sequences in Cnidaria and Ctenophora, basal phyla of metazoans, PCR with highly degenerate oligonucleotides was performed and an RT-like sequence was identified from the sea anemone species Anemonia sulcata. Further screening identified a related element in another anemone species Actinia equina. Significant homology to non-LTR retrotransposon RTs was observed, particularly to L2-like elements of fish such as Maui. The sequence was not detected among other cnidarians and we have designated the A. sulcata and A. equina elements Abyss1 and Abyss2 respectively. Phylogenetic analysis of Abyss1 compared with members of 14 known non-LTR retroelement clades suggests that the sequence represents a novel L2 element.
非长末端重复反转录转座子是一类多样且在分类学上广泛分布的反转录元件，可分为至少14个可区分的进化枝。后生动物的基部类群尚未对其反转录转座子含量进行详细研究。为了筛选后生动物基部类群刺胞动物门和栉水母动物门中与逆转录酶（RT）相关序列的存在情况，使用高度简并的寡核苷酸进行了聚合酶链反应（PCR），并从海葵物种沟迎风海葵中鉴定出一个类RT序列。进一步筛选在另一种海葵物种马氏海葵中鉴定出一个相关元件。观察到与非长末端重复反转录转座子RTs有显著同源性，特别是与鱼类的L2样元件如毛伊岛鱼的同源性。在其他刺胞动物中未检测到该序列，我们分别将沟迎风海葵和马氏海葵的元件命名为Abyss1和Abyss2。将Abyss1与14个已知非长末端重复反转录元件进化枝的成员进行系统发育分析表明，该序列代表一个新的L2元件。
