NgAgo, a new potential breakthrough in gene editing was recently described by Chunyu Han , a biologist at Hebei University of Science and Technology in Shijiazhuang. Like the CRISPR/Cas9 system, it allowed targeted editing at specific sites in the mammalian genome, just by choosing a small matching sequence. There were two main advantages over Cas9 which made it an attractive proposition. First, it did not require a PAM site so it could theoretically target more sites in the genome, and second, it used DNA guides instead of RNA ones, which would make the experiments even easier and cheaper.
There was a problem, though. When the paper broke, scientists all over the world rushed to get the reagents in their labs and try it for themselves. And pretty much none of them could get it to work. This culminated in many blogs, leaked emails and researchers condemning the original work and demanding more experimental details from the publishing journal and Chunyu Han .
Now, a clutch of new letters and articles, summarised in a recent Nature report, have cast even more doubt on the function of the system. In particular, eight separate laboratories attempted to repeat the original editing experiments with no success. A separate publication showed that NgAgo may actually bind to the DNA to block gene transcription, rather than cutting it directly.
Whether this failure is due to errors in the original interpretation of the initial results, a case of deception by Han, or just an experiment that is difficult to replicate successfully for some reason, is unknown at this time.
Science is full of stories of blind alleys; it's one of the risks of being at the bleeding edge of discovery, but I fully understand the frustration of researchers who have spent time and money trying to get a new technology to work.
Personally, I'm glad I waited now before I tried to get it to work in my own lab.
1. Gao, F., Shen, X. Z., Jiang, F., Wu, Y. & Han, C. Nature Biotech. 34, 768–773 (2016).
2. Burgess, S. et al. Protein Cell http://dx.doi.org/10.1007/s13238-016-0343-9 (2016).
3. Qi, J. et al. Cell Res. http://dx.doi.org/10.1038/cr.2016.134 (2016).