Malik H S, Eickbush T H
Department of Biology, University of Rochester, New York 14627, USA.
Mol Biol Evol. 1998 Sep;15(9):1123-34. doi: 10.1093/oxfordjournals.molbev.a026020.
RTE-1 is a non-long-terminal-repeat (non-LTR) retrotransposable element first found in the Caenorhabditis elegans genome. It encodes a 1,024-amino-acid open reading frame (ORF) containing both apurinic-apyrimidic endonuclease and reverse-transcriptase domains. A possible first ORF of only 43 amino acids overlaps with the larger ORF and may be the site of translation initiation. Database searches and phylogenetic analysis indicate that representatives of the RTE clade of non-LTR retrotransposons are found in the bovine and sheep genomes of mammals and in the silkmoth and mosquito genomes of insects. In addition, the previously identified SINEs, Art2 and Pst, from ruminate and viper genomes are shown to be truncated RTE-like retrotransposable elements. RTE-derived SINE elements are also found in mollusc and flatworm genomes. Members of the RTE clade are characterized by unusually short 3' untranslated regions that are predominantly composed of AT-rich trimer, tetramer, and/or pentamer repeats. This study establishes RTE as a very widespread clade of non-LTR retrotransposons. RTE represents the third distinct class of non-LTR retrotransposons in the vertebrate lineage (after Line 1 elements in mammals and CR1 elements in birds and reptiles).
RTE-1是一种非长末端重复（non-LTR）反转录转座元件，最初在秀丽隐杆线虫基因组中被发现。它编码一个包含脱嘌呤-脱嘧啶内切核酸酶和逆转录酶结构域的1024个氨基酸的开放阅读框（ORF）。一个仅43个氨基酸的可能的首个ORF与较大的ORF重叠，可能是翻译起始位点。数据库搜索和系统发育分析表明，非LTR反转录转座子的RTE分支的代表存在于哺乳动物的牛和羊基因组以及昆虫的家蚕和蚊子基因组中。此外，先前从反刍动物和蝰蛇基因组中鉴定出的短散在核元件（SINEs）Art2和Pst被证明是截短的RTE样反转录转座元件。在软体动物和扁虫基因组中也发现了源自RTE的SINE元件。RTE分支的成员的特征是异常短的3'非翻译区，主要由富含AT的三聚体、四聚体和/或五聚体重复序列组成。这项研究将RTE确立为一个非常广泛的非LTR反转录转座子分支。RTE代表脊椎动物谱系中第三类不同的非LTR反转录转座子（仅次于哺乳动物中的1类元件和鸟类及爬行动物中的CR1元件）。
