Centre for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, Bonn, Germany.
Evolutionary Biology & Ecology, Institute for Biology I, University of Freiburg, Freiburg (Brsg.), Germany.
Genome Biol Evol. 2016 Dec 1;8(12):3784-3793. doi: 10.1093/gbe/evw281.
RNA interference (RNAi) refers to the set of molecular processes found in eukaryotic organisms in which small RNA molecules mediate the silencing or down-regulation of target genes. In insects, RNAi serves a number of functions, including regulation of endogenous genes, anti-viral defense, and defense against transposable elements. Despite being well studied in model organisms, such as Drosophila, the distribution of core RNAi pathway genes and their evolution in insects is not well understood. Here we present the most comprehensive overview of the distribution and diversity of core RNAi pathway genes across 100 insect species, encompassing all currently recognized insect orders. We inferred the phylogenetic origin of insect-specific RNAi pathway genes and also identified several hitherto unrecorded gene expansions using whole-body transcriptome data from the international 1KITE (1000 Insect Transcriptome Evolution) project as well as other resources such as i5K (5000 Insect Genome Project). Specifically, we traced the origin of the double stranded RNA binding protein R2D2 to the last common ancestor of winged insects (Pterygota), the loss of Sid-1/Tag-130 orthologs in Antliophora (fleas, flies and relatives, and scorpionflies in a broad sense), and confirm previous evidence for the splitting of the Argonaute proteins Aubergine and Piwi in Brachyceran flies (Diptera, Brachycera). Our study offers new reference points for future experimental research on RNAi-related pathway genes in insects.
RNA 干扰 (RNAi) 是指在真核生物中发现的一系列分子过程，其中小 RNA 分子介导靶基因的沉默或下调。在昆虫中，RNAi 具有多种功能，包括内源性基因的调控、抗病毒防御和转座元件防御。尽管在模式生物如果蝇中得到了很好的研究，但昆虫中核心 RNAi 途径基因的分布及其进化尚不清楚。在这里，我们展示了对 100 种昆虫物种中核心 RNAi 途径基因分布和多样性的最全面概述，涵盖了所有目前公认的昆虫目。我们推断了昆虫特异性 RNAi 途径基因的进化起源，并且还使用来自国际 1KITE（1000 种昆虫转录组进化）项目的全身转录组数据以及其他资源（如 i5K（5000 种昆虫基因组计划））鉴定了几个迄今为止未记录的基因扩展。具体来说，我们追踪了双链 RNA 结合蛋白 R2D2 的起源，该蛋白的起源可追溯到有翅昆虫（翼龙）的最后共同祖先，Antliophora（跳蚤、苍蝇及其亲属、广义上的蝎子苍蝇）中失去了 Sid-1/Tag-130 同源物，并且证实了以前关于 Argonaute 蛋白 Aubergine 和 Piwi 在短角蝇（双翅目，短角蝇）中分裂的证据。我们的研究为未来昆虫中与 RNAi 相关的途径基因的实验研究提供了新的参考点。
