BACKGROUND Gene silencing by RNA interference (RNAi) is a powerful tool for functional genomics. Although RNAi was first described in Caenorhabditis elegans, several nematode species are unable to mount an RNAi response when exposed to exogenous double stranded RNA (dsRNA). These include the satellite model organisms Pristionchus pacificus and Oscheius tipulae. Available data also suggest that the RNAi pathway targeting exogenous dsRNA may not be fully functional in some animal parasitic nematodes. The genus Panagrolaimus contains bacterial feeding nematodes which occupy a diversity of niches ranging from polar, temperate and semi-arid soils to terrestrial mosses. Thus many Panagrolaimus species are adapted to tolerate freezing and desiccation and are excellent systems to study the molecular basis of environmental stress tolerance. We investigated whether Panagrolaimus is susceptible to RNAi to determine whether this nematode could be used in large scale RNAi studies in functional genomics. RESULTS We studied two species: Panagrolaimus sp. PS1159 and Panagrolaimus superbus. Both nematode species displayed embryonic lethal RNAi phenotypes following ingestion of Escherichia coli expressing dsRNA for the C. elegans embryonic lethal genes Ce-lmn-1 and Ce-ran-4. Embryonic lethal RNAi phenotypes were also obtained in both species upon ingestion of dsRNA for the Panagrolaimus genes ef1b and rps-2. Single nematode RT-PCR showed that a significant reduction in mRNA transcript levels occurred for the target ef1b and rps-2 genes in RNAi treated Panagrolaimus sp. 1159 nematodes. Visible RNAi phenotypes were also observed when P. superbus was exposed to dsRNA for structural genes encoding contractile proteins. All RNAi phenotypes were highly penetrant, particularly in P. superbus. CONCLUSION This demonstration that Panagrolaimus is amenable to RNAi by feeding will allow the development of high throughput methods of RNAi screening for P. superbus. This greatly enhances the utility of this nematode as a model system for the study of the molecular biology of anhydrobiosis and cryobiosis and as a possible satellite model nematode for comparative and functional genomics. Our data also identify another nematode infraorder which is amenable to RNAi and provide additional information on the diversity of RNAi phenotypes in nematodes.

中文翻译：

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系统性 RNAi 介导的脱水线虫 Panagrolaimus superbus 中的基因沉默。


背景技术通过RNA干扰(RNAi)进行的基因沉默是功能基因组学的强大工具。尽管 RNAi 首次在秀丽隐杆线虫中被描述，但一些线虫物种在暴露于外源双链 RNA (dsRNA) 时无法产生 RNAi 反应。其中包括卫星模式生物Pristionchus pacificus 和Oscheius Tipulae。现有数据还表明，针对外源 dsRNA 的 RNAi 途径在某些动物寄生线虫中可能无法完全发挥作用。 Panagrolaimus 属包含以细菌为食的线虫，它们占据从极地、温带和半干旱土壤到陆地苔藓的多种生态位。因此，许多Panagrolaimus物种都适应了冷冻和干燥，并且是研究环境胁迫耐受性的分子基础的优秀系统。我们研究了 Panagrolaimus 是否对 RNAi 敏感，以确定这种线虫是否可以用于功能基因组学的大规模 RNAi 研究。结果 我们研究了两个物种：Panagrolaimus sp。 PS1159 和 Panagrolaimus 超级巴士。两种线虫在摄入表达线虫胚胎致死基因 Ce-lmn-1 和 Ce-ran-4 dsRNA 的大肠杆菌后均表现出胚胎致死 RNAi 表型。在摄入 Panagrolaimus 基因 ef1b 和 rps-2 的 dsRNA 后，这两个物种也获得了胚胎致死性 RNAi 表型。单一线虫 RT-PCR 显示，RNAi 处理的 Panagrolaimus sp. 中靶标 ef1b 和 rps-2 基因的 mRNA 转录水平显着降低。第1159章 线虫当 P. superbus 暴露于编码收缩蛋白的结构基因的 dsRNA 时，也观察到可见的 RNAi 表型。所有 RNAi 表型均具有高度渗透性，特别是在 P. superbus 中。 结论 Panagrolaimus 能够通过喂养进行 RNAi 的证明将有助于开发 P. superbus RNAi 筛选的高通量方法。这极大地增强了该线虫作为研究脱水和冷冻分子生物学的模型系统以及作为用于比较和功能基因组学的可能的卫星模型线虫的实用性。我们的数据还确定了另一种适合 RNAi 的线虫亚目，并提供了有关线虫 RNAi 表型多样性的更多信息。