Center for Evolutionary Origins of Human Behavior, Kyoto University, Inuyama 484-8506, Japan; Animal Genomics and Bioresource Research Unit, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
Virology. 2023 Sep;586:56-66. doi: 10.1016/j.virol.2023.07.005. Epub 2023 Jul 19.
The kangaroo endogenous retrovirus (KERV) was previously reported to have undergone a rapid copy number increase in the red-necked wallaby; however, the mode of amplification was left to be clarified. The present study revealed that the long terminal repeat (LTR) (0.6 kb) and internal region (2.0 kb) of a provirus are repeated alternately, forming megasatellite DNA which we named kervRep. This repetition pattern was the same as that observed for walbRep, megasatellite DNA originating from another endogenous retrovirus. Their formation process can be explained using a simple model: pairing slippage followed by homologous recombination. This model features that the initial step is triggered by the presence of two identical sequences within a short distance; the possession of LTRs by endogenous retroviruses fulfills this condition. The discovery of two cases suggests that formation of this type of satellite DNA is one of non-negligible effects of endogenous retroviruses on their host genomes.
袋鼠内源性逆转录病毒（KERV）先前被报道在红颈袋鼠中经历了快速的拷贝数增加；然而，扩增的模式仍有待澄清。本研究揭示了一种前病毒的长末端重复（LTR）（0.6 kb）和内部区（2.0 kb）交替重复，形成了我们称之为 kervRep 的大片段卫星 DNA。这种重复模式与来自另一种内源性逆转录病毒的 walbRep 大片段卫星 DNA 相同。它们的形成过程可以用一个简单的模型来解释：配对滑动 followed by 同源重组。该模型的特点是初始步骤由短距离内两个相同序列的存在触发；内源性逆转录病毒的 LTR 满足此条件。这两个案例的发现表明，这种类型的卫星 DNA 的形成是内源性逆转录病毒对其宿主基因组的一个不可忽视的影响之一。
