Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, CEP 30270-901, Brazil.
Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, BA, CEP 40101-909, Brazil.
RNA. 2020 May;26(5):581-594. doi: 10.1261/rna.073965.119. Epub 2020 Jan 29.
Endogenous viral elements (EVEs) are found in many eukaryotic genomes. Despite considerable knowledge about genomic elements such as transposons (TEs) and retroviruses, we still lack information about nonretroviral EVEs. mosquitoes have a highly repetitive genome that is covered with EVEs. Here, we identified 129 nonretroviral EVEs in the AaegL5 version of the genome. These EVEs were significantly associated with TEs and preferentially located in repeat-rich clusters within intergenic regions. Genome-wide transcriptome analysis showed that most EVEs generated transcripts although only around 1.4% were sense RNAs. The majority of EVE transcription was antisense and correlated with the generation of EVE-derived small RNAs. A single genomic cluster of EVEs located in a 143 kb repetitive region in chromosome 2 contributed with 42% of antisense transcription and 45% of small RNAs derived from viral elements. This region was enriched for TE-EVE hybrids organized in the same coding strand. These generated a single long antisense transcript that correlated with the generation of phased primary PIWI-interacting RNAs (piRNAs). The putative promoter of this region had a conserved binding site for the transcription factor Cubitus interruptus, a key regulator of the locus in Here, we have identified a single unidirectional piRNA cluster in the genome that is the major source of EVE transcription fueling the generation of antisense small RNAs in mosquitoes. We propose that this region is a locus in due to its relatedness to the major unidirectional piRNA cluster in .
内源性病毒元件 (EVEs) 存在于许多真核生物基因组中。尽管我们对转座子 (TEs) 和逆转录病毒等基因组元件有了相当多的了解，但我们仍然缺乏关于非逆转录病毒 EVEs 的信息。蚊子具有高度重复的基因组，覆盖着 EVEs。在这里，我们在 基因组的 AaegL5 版本中鉴定了 129 个非逆转录病毒 EVEs。这些 EVEs 与 TEs 显著相关，并优先位于基因间区域富含重复序列的簇中。全基因组转录组分析表明，大多数 EVEs 产生转录本，尽管只有约 1.4%是有意义的 RNA。EVE 转录的大部分是反义的，并与 EVE 衍生的小 RNA 的产生相关。位于染色体 2 上一个 143kb 重复区域的单个 EVEs 基因组簇贡献了 42%的反义转录和 45%的源自病毒元件的小 RNA。该区域富含以相同编码链排列的 TE-EVE 杂种。这些产生了一个单一的长反义转录本，与相分期的初级 PIWI 相互作用 RNA (piRNAs) 的产生相关。该区域的假定启动子具有转录因子 Cubitus interruptus 的保守结合位点，Cubitus interruptus 是 基因座在 中的关键调节因子。在这里，我们在 基因组中鉴定了一个单一的单向 piRNA 簇，它是 EVE 转录的主要来源，为蚊子中反义小 RNA 的产生提供燃料。我们提出，由于该区域与 中的主要单向 piRNA 簇具有亲缘关系，因此它是 中的一个 基因座。
