PMID- 26204993 OWN - NLM STAT- MEDLINE DCOM- 20160802 LR - 20240104 IS - 2045-2322 (Electronic) IS - 2045-2322 (Linking) VI - 5 DP - 2015 Jul 24 TI - A pre-screening FISH-based method to detect CRISPR/Cas9 off-targets in mouse embryonic stem cells. PG - 12327 LID - 10.1038/srep12327 [doi] LID - 12327 AB - The clustered regularly interspaced short palindromic repeat (CRISPR)/associated 9 (Cas9) technology has been recently added to the tools allowing efficient and easy DNA targeting, representing a very promising approach to gene engineering. Using the CRISPR/Cas9 system we have driven the integration of exogenous DNA sequences to the X-linked Hprt gene of mouse embryonic stem cells. We show here that a simple fluorescence in situ hybridization (FISH)-based strategy allows the detection and the frequency evaluation of non-specific integrations of a given plasmid. FISH analysis revealed that these integrations do not match the software predicted off-target loci. We conclude that the frequency of these CRISPR-mediated off-target DNA cuts is negligible, since, due to the occurrence of spontaneous double-strand breaks, we observed more aspecific plasmid integrations than those corresponding to predicted off-target sites. FAU - Paulis, Marianna AU - Paulis M AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. FAU - Castelli, Alessandra AU - Castelli A AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. FAU - Lizier, Michela AU - Lizier M AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. FAU - Susani, Lucia AU - Susani L AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. FAU - Lucchini, Franco AU - Lucchini F AD - Catholic University of the Sacred Heart, Cremona, Italy. FAU - Villa, Anna AU - Villa A AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. FAU - Vezzoni, Paolo AU - Vezzoni P AD - 1] Milan Unit, Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, Milan, Italy [2] Humanitas Clinical and Research Center, Rozzano, Milan, Italy. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20150724 PL - England TA - Sci Rep JT - Scientific reports JID - 101563288 RN - EC 2.4.2.8 (Hypoxanthine Phosphoribosyltransferase) SB - IM MH - Animals MH - *CRISPR-Cas Systems MH - Hypoxanthine Phosphoribosyltransferase/genetics/metabolism MH - In Situ Hybridization, Fluorescence/*methods MH - Mice MH - Mouse Embryonic Stem Cells/cytology/*metabolism PMC - PMC4513284 EDAT- 2015/07/25 06:00 MHDA- 2016/08/03 06:00 PMCR- 2015/07/24 CRDT- 2015/07/25 06:00 PHST- 2014/11/03 00:00 [received] PHST- 2015/05/22 00:00 [accepted] PHST- 2015/07/25 06:00 [entrez] PHST- 2015/07/25 06:00 [pubmed] PHST- 2016/08/03 06:00 [medline] PHST- 2015/07/24 00:00 [pmc-release] AID - srep12327 [pii] AID - 10.1038/srep12327 [doi] PST - epublish SO - Sci Rep. 2015 Jul 24;5:12327. doi: 10.1038/srep12327.