韩春雨争议升级：ISTT发文质疑——却遭专家质疑其权威性

   韩春雨基因编辑实验可重复性争议升级，国际转基因技术协会(ISTT)在其推特和群发邮件中公开质疑，呼吁大家不要再浪费时间、金钱、人力和课题，并在文末并高呼Long Life to CRISPR, CRISPR万岁!

　　赛先生今晨以“多国科学家宣布：迄今未能重复韩春雨NgAgo实验结果”进行深度报道，国内亦有专业人士也在新浪微博公开质疑国际转基因技术协会权威性。

　　知社一贯坚持科学问题应由科学家解决、并受同行评议检验。在此刊登ITSS质疑的群发邮件供大家评判。为避免误解，英文邮件就不翻译了。

　　知社亦须指出，CRISPR, TtAgo, 以及NgAgo之间，存在潜在的直接竞争关系、巨大利益冲突、和巨额市场争夺。这一点，从ISTT群发邮件可以明显看出：I must confess we read the Han paper in my lab with some disappointment...We had been scooped...Long Life to CRISPR，其最初的失望之情溢于言表。这样的竞争和利益冲突，使得当前的争议更加扑朔迷离。

　　基于此，知社在文末也刊登专业人士对ITSS的质疑，供大家参考、判断。这个是中文的，无需翻译。

　　知社重申，时间会证明一切，大家不妨耐心一点。。。

　　ITSS群发邮件原文

　　Dear colleagues,

　　The publication by Gao et al in May in Nature Biotechnology (http://www.ncbi.nlm.nih.gov/pubmed/27136078) triggered an enormous expectation. This Chinese team led by Chunyu Huan reported that the Argonaute (Ago) protein from a rare haloarchaea, Natronobacterium gregoryi, (NgAgo) would efficiently work for gene editing purposes in human cells. Ago had been described as an DNA-guided endonucleases two years before, through a Dutch-Spanish microbiologist collaborating team (Swarts et al. 2014, Nature: http://www.ncbi.nlm.nih.gov/pubmed/24531762).

　　On paper, the new (fourth) Gene Editing system looked great. An endonucleas, using ssDNA guides (5' phosphorylated though) and not RNA guides, without a PAM, requiring 24 nucleotides (and not 20nt), hence with higher specificity, and apparently with fewer off-target issues, since modifications in just one position of the DNA guide resulted in >90% decrease of the protein activity.

　　On paper.

　　I must confess we read the Huan paper in my lab with some disappointment, after two years battling, unsuccessfully, with Ago from Thermus, through a collaboration with my friend and colleague J. Berenguer, from the

　　neighbouring reserch centre CBMSO, and one of the co-authors of the Nature

　　2014 paper. We had been scooped. We repeteadly failed to find any gene

　　editing activity using Ago from Thermus thermophilus (TtAgo) in mammalian

　　cells, through a variety of conditions and we didn't understand why, though

　　we always suspected that these proteins would not be too comfortable at "too

　　cold" temperatures as physiological +37C. After reading the Gao paper we

　　concluded we simply missed the right bug and congratulated them for being

　　smarter and lucky and for finding this archaea. Perhaps the trick was in

　　using NgAgo instead of TtAgo.

　　Shortly after NgAgo was released from Addgene, beginning of June, many labs, including mine, jumped onto it to try experiencing the anticipated great

　　expectations and joy associated with this new tool of prokaryotic origin.

　　But soon it was clear that something wasn't quite right. Rumours began

　　spreading during June and July at congresses, through social networks, list

　　emails and discussions groups that NgAgo didn't appear to work as reported.

　　Actually, didn't work at all. Some colleagues that I absolutely trust at

　　scientitic and technological levels started to indicate that they could not

　　reproduce Huan's paper results.

　　At the recent TAGC meeting (where IMGS was contributing to, merging in along with other Genetics Societies) Gaetan Burgio, from ANU, Camberra, Australia, presented some very preliminary data with a gel with some intermediate

　　bands that would suggest NgAgo would be working and editing at the expected places. But, shortly thereafter, Gaetan engaged his lab in an OpenScience

　　project, tried to characterize all these bands and.... found nothing. So,

　　again, another evidence confirming NgAgo is not working as a gene-editing

　　tool.

　　Gaeatan just released today his experience using NgAgo, openly sharing his

　　failures and providing details and some explanations for them.

　　My experience with Natronobacterium gregoryi Argonaute (NgAgo)

　　Gaetan Burgio

　　Group leader at JCSMR, ANU

　　https://medium.com/@GaetanBurgio/my-experience-with-natronobacterium-

　　gregoryi-argonaute-ngago-3ed8909b410c#.bo9y6mf9u

　　At first, KUDOS to Gaetan. Many thanks to him for sharing their efforts

　　trying to confirm some gene-editing activity associated with NgAgo. There is

　　apparently none. In his view, NgAgo might be working as a ligase at

　　physiological conditions. Similar to our negative results using TtAgo it

　　would appear that NgAgo requires some higher temperatures to work as

　　initially reported. This of course seeds some doubts on the Gao et al.

　　publication and Gaetan, among other, is requesting to Nature Biotechnology

　　to request the Huan's lab to reveal and share their raw data. We will see

　　this part of the history how it develops...

　　But, now, the most important message to convey is: NgAgo does not work for gene editing in mammalian cells. Be aware and do not waste your time, your money, your peoople and projects. If anyone has any positive hint suggesting Ago is indeed working as a genomic editor, please share the results, for the sake of Open Science, as Gaetan beautifully and most generously did. Many thanks to Gaetan!

　　Unfortunately, this is a great disappointment. But, it also highlights the

　　uniqueness and the robustness of the CRISPR-Cas systems.

　　Long life to CRISPR!

　　新浪微博质疑ITSS

　　ISTT公开质疑与选边站台，也引发新浪微博知名博主反弹，国际转基因技术协会是什么鬼?

　　而在这一争议中异常活跃的MITBBS，也有多名ID质疑ITSS所引澳洲国立大学Gaetan Burgio博士的实验技术问题和错误：

　　究竟是学术争议、利益冲突、或是经济纠葛，相信时间终会给出答案。大家不妨耐心一点。