The editors of Nature Biotechnology are issuing an editorial expression of concern regarding this article to alert our readers to concerns regarding the reproducibility of the original results. At this time, we are publishing the results of three groups (http://dx.doi.org/10.1038/nbt.3753) that have tried to reproduce the results in the critical Figure 4 in the original paper by Han and colleagues, which demonstrates editing of endogenous genomic loci in mammalian cells. None of the groups observed any induction of mutations by NgAgo at any of the loci or under any of the conditions tested above the sensitivity of the assays used. Similar results have been recently reported by a different group of authors in Protein & Cell (doi:10.1007/s13238-016-0343-9).
We are in contact with the authors, who are investigating potential causes for the lack of reproducibility. The authors have been informed of this statement. While the investigations are ongoing, Chunyu Han and Xiao Z. Shen agree with this editorial expression of concern. Feng Gao, Feng Jiang and Yongqiang Wu do not feel that it is appropriate at this time.
We will update our readers once these investigations are complete.