Triplex-forming oligonucleotide-orthophenanthroline conjugates for efficient targeted genome modification
Authors: Ulysse Asseline
Slimane Ait-Si-Ali
Victoria Roig
Carine Giovannangeli
Jean-Paul Concordet
Loïc Perrouault
Erika Brunet
Fabio Cannata
Journal: Proceedings of the National Academy of Sciences of the United States of America (2008)
Discipline: Multidisciplinary
Keywords: gene modification; homologous recombination; double-strand break (DSB); endonucleases; orthophenanthroline (OP)
Affiliations: Laboratoire de Biophysique, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5153 USM 503, and Institut National de la Santé et de la Recherche Médicale U565, Muséum National d'Histoire Naturelle, 43 Rue Cuvier, 75005 Paris, France.

Abstract:  The inefficiency of gene modification by homologous recombination can be overcome by the introduction of a double-strand break (DSB) in the target. Engineering the endonucleases needed, however, remains a challenging task that limits widespread application of nuclease-driven gene modification. We report here that conjugates of orthophenanthroline (OP), a DNA cleaving molecule, and triplex-forming oligonucleotides (TFOs), known to bind specific DNA sequences, are synthetic nucleases efficient at stimulating targeted genome modification. We show that in cultured cells, OP-TFO conjugates induce targeted DSBs. An OP-TFO with a unique target was highly efficient, and mutations at the target site were found in approximately 10% of treated cells, including small deletions most likely introduced during DSB repair by nonhomologous end joining. Importantly, we found that when homologous donor DNA was cotransfected, targeted gene modification took place in &gt;1.5% of treated cells. Because triplex-forming sequences are frequent in human and mouse genes, OP-TFO conjugates therefore constitute an important class of site-specific nucleases for targeted gene modification. Harnessing DNA-damaging molecules to predetermined genomic sites, as achieved here, should also provide inroads into mechanisms of DNA repair and cancer. 

Retracted: Yes

PubPeer comments:
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 Dear Penicillium Citreoviride, Thanks for your comment, we have examined our raw data and paper carefully. As your comment pointed out, we find that a picture of AO-EB cell staining in the Placebo control group was misused. I am very sorry for the inconvenient bringing to readers. However, the misuse does not affect the result and conclusion of the paper. Now, I have contacted the editorial office for correction. , 
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