Perrimon Norbert, Mathey-Prevot Bernard
Department of Genetics, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts USA.
Fly (Austin). 2007 Jan-Feb;1(1):1-5. doi: 10.4161/fly.3601.
Recently, the issue of off-target effects (OTEs) associated with long double stranded RNAs (dsRNAs) used in RNAi screens, such as those performed at the Drosophila RNAi Screening Center and other laboratories, has become a focus of great interest and some concern. Although OTEs have been recognized as an important source of false positives in mammalian studies (where short siRNAs are used as triggers), they were generally thought to be inconsequential in Drosophila RNAi experiments because of the use of long dsRNAs. Two recent papers have disputed this contention and show that significant off-target effects can take place with the use of some long dsRNAs in Drosophila cells. Together, these studies provide evidence that OTEs mediated by short homology stretches of 19nt or greater within long dsRNAs can contribute to false positives in Drosophila RNAi screens. Here, we address how widespread the occurrence of OTE is in Drosophila screens, focusing on the DRSC dsRNA collections, and we discuss the implication for the interpretation of results reported in RNAi screens to-date. Lastly, we summarize steps taken by the DRSC to redress that situation and include a set of recommendations to observe in future RNAi screens.
最近，与RNA干扰（RNAi）筛选中使用的长双链RNA（dsRNA）相关的脱靶效应（OTE）问题，比如在果蝇RNAi筛选中心及其他实验室所进行的筛选，已成为备受关注且引发一定担忧的焦点。尽管在哺乳动物研究中（使用短干扰RNA（siRNA）作为触发物），脱靶效应已被视为假阳性的一个重要来源，但由于使用了长双链RNA，人们通常认为其在果蝇RNAi实验中无关紧要。最近的两篇论文对这一观点提出了质疑，并表明在果蝇细胞中使用某些长双链RNA会产生显著的脱靶效应。这些研究共同提供了证据，表明长双链RNA中19个核苷酸或更长的短同源序列介导的脱靶效应可能导致果蝇RNAi筛选中的假阳性。在此，我们探讨脱靶效应在果蝇筛选中的普遍程度，重点关注果蝇RNAi筛选中心的dsRNA文库，并讨论其对迄今RNAi筛选中所报告结果解读的影响。最后，我们总结了果蝇RNAi筛选中心为纠正这种情况所采取的措施，并给出了一系列在未来RNAi筛选中需遵循的建议。
