Vavilov Institute of General Genetics Russian Academy of Sciences, 119991 Moscow, Russia.
Genes (Basel). 2020 Oct 15;11(10):1202. doi: 10.3390/genes11101202.
The structural and functional organization of the ribosomal RNA gene cluster and the full-length R2 non-LTR retrotransposon (integrated into a specific site of 28S ribosomal RNA genes) of the German cockroach, , is described. A partial sequence of the R2 retrotransposon of the cockroach is also analyzed. The analysis of previously published next-generation sequencing data from the genome reveals a new type of retrotransposon closely related to R2 retrotransposons but with a random distribution in the genome. Phylogenetic analysis reveals that these newly described retrotransposons form a separate clade. It is shown that proteins corresponding to the open reading frames of newly described retrotransposons exhibit unequal structural domains. Within these retrotransposons, a recombination event is described. New mechanism of transposition activity is discussed. The essential structural features of R2 retrotransposons are conserved in cockroaches and are typical of previously described R2 retrotransposons. However, the investigation of the number and frequency of 5'-truncated R2 retrotransposon insertion variants in eight populations suggests recent mobile element activity. It is shown that the pattern of 5'-truncated R2 retrotransposon copies can be an informative molecular genetic marker for revealing genetic distances between insect populations.
描述了德国蟑螂的核糖体 RNA 基因簇的结构和功能组织以及全长 R2 非 LTR 反转录转座子（整合到 28S 核糖体 RNA 基因的特定位点）。还分析了蟑螂 R2 反转录转座子的部分序列。对 基因组的先前发表的下一代测序数据的分析揭示了一种与 R2 反转录转座子密切相关但在基因组中随机分布的新型反转录转座子。系统发育分析表明，这些新描述的反转录转座子形成一个单独的分支。结果表明，与新描述的反转录转座子的开放阅读框相对应的蛋白质表现出不等的结构域。在这些反转录转座子内，描述了一个重组事件。讨论了新的转位活性机制。R2 反转录转座子的基本结构特征在蟑螂中保守，与先前描述的 R2 反转录转座子典型。然而，对 8 个 种群中 5'-截短 R2 反转录转座子插入变体的数量和频率的研究表明，最近存在移动元件活性。结果表明，5'-截短 R2 反转录转座子拷贝的模式可以作为揭示昆虫种群之间遗传距离的信息分子遗传标记。
