Department of Molecular and Cell Biology, University of Connecticut, 354 Mansfield Rd., U2131, Storrs, CT 06269, USA.
J Virol. 2011 May;85(10):4761-71. doi: 10.1128/JVI.01604-10. Epub 2011 Mar 9.
Mammalian retrotransposons, transposable elements that are processed through an RNA intermediate, are categorized as short interspersed elements (SINEs), long interspersed elements (LINEs), and long terminal repeat (LTR) retroelements, which include endogenous retroviruses. The ability of transposable elements to autonomously amplify led to their initial characterization as selfish or junk DNA; however, it is now known that they may acquire specific cellular functions in a genome and are implicated in host defense mechanisms as well as in genome evolution. Interactions between classes of transposable elements may exert a markedly different and potentially more significant effect on a genome than interactions between members of a single class of transposable elements. We examined the genomic structure and evolution of the kangaroo endogenous retrovirus (KERV) in the marsupial genus Macropus. The complete proviral structure of the kangaroo endogenous retrovirus, phylogenetic relationship among relative retroviruses, and expression of this virus in both Macropus rufogriseus and M. eugenii are presented for the first time. In addition, we show the relative copy number and distribution of the kangaroo endogenous retrovirus in the Macropus genus. Our data indicate that amplification of the kangaroo endogenous retrovirus occurred in a lineage-specific fashion, is restricted to the centromeres, and is not correlated with LINE depletion. Finally, analysis of KERV long terminal repeat sequences using massively parallel sequencing indicates that the recent amplification in M. rufogriseus is likely due to duplications and concerted evolution rather than a high number of independent insertion events.
哺乳动物反转录转座子是通过 RNA 中间体加工的可移动元件，可分为短散布元件（SINEs）、长散布元件（LINEs）和长末端重复（LTR）反转录元件，其中包括内源性逆转录病毒。转座元件能够自主扩增，这导致它们最初被特征化为自私或垃圾 DNA；然而，现在已知它们可能在基因组中获得特定的细胞功能，并与宿主防御机制以及基因组进化有关。转座元件类之间的相互作用可能对基因组产生明显不同且潜在更重要的影响，而不是单个转座元件类成员之间的相互作用。我们研究了袋鼠内源性逆转录病毒（KERV）在有袋类属 Macropus 中的基因组结构和进化。我们首次提出了袋鼠内源性逆转录病毒的完整前病毒结构、相对逆转录病毒之间的系统发育关系以及该病毒在 Macropus rufogriseus 和 M. eugenii 中的表达。此外，我们还展示了袋鼠内源性逆转录病毒在 Macropus 属中的相对拷贝数和分布。我们的数据表明，袋鼠内源性逆转录病毒的扩增是以谱系特异性的方式发生的，仅限于着丝粒，并且与 LINE 耗竭无关。最后，使用大规模平行测序对 KERV 长末端重复序列进行分析表明，M. rufogriseus 中的近期扩增可能是由于重复和协同进化而不是大量独立的插入事件所致。
