{"id":3507,"date":"2018-04-16T13:56:28","date_gmt":"2018-04-16T04:56:28","guid":{"rendered":"http:\/\/www.med.osaka-u.ac.jp\/eng\/?page_id=3507"},"modified":"2022-08-08T11:35:19","modified_gmt":"2022-08-08T02:35:19","slug":"nakada0202","status":"publish","type":"page","link":"https:\/\/www.med.osaka-u.ac.jp\/eng\/activities\/results\/2018year\/nakada0202","title":{"rendered":"NAKADA Shinichiro \u226aBioregulation and Cellular Response\u226b <span>New genome-editing method \u201ccuts back\u201d on unwanted genetic mutations<\/span>"},"content":{"rendered":"<ul class=\"linkBar clearfix\">\n<li><a href=\"http:\/\/www.med.osaka-u.ac.jp\/activities\/results\/2018year\/nakada0202\">Text in Japanese<\/a><\/li>\n<\/ul>\n<p>2018-02-02<\/p>\n<p><span class=\"lineFrame\">Publish<\/span> Genome Research<\/p>\n<p>Researchers at Osaka University develop novel method that can introduce precise modifications to defective genes with fewer safety drawbacks.<\/p>\n<p class=\"figure\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-3513 size-medium\" src=\"http:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3-e1523867462231-400x295.png?_t=1523867463\" alt=\"\" width=\"400\" height=\"295\" srcset=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3-e1523867462231-400x295.png 400w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3-e1523867462231-768x567.png 768w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3-e1523867462231-1024x756.png 1024w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3-e1523867462231.png 1303w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><a href=\"http:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2018\/04\/795316b92fc766b0181f6fef074f03fa-3.png\">\u00a0<span class=\"caption\">Fig. 1. Cas9 introduces a DNA double-strand break in the target gene, allowing the gene to be edited when a repair template is present. A drawback to the CRISPR\/Cas9 system is that the cellular DNA repair machinery can introduce inaccuracies following a double-strand break (left panel). Nakajima et al report a new gene-editing method that avoids the formation of double-strand breaks. Cas9 nickase produces a combination of single nicks in the genome and the DNA carrying the repair template, resulting in precise and efficient gene editing (right panel). <br \/><\/span><span class=\"click\">Click to enlarge<\/span>\u00a0<\/a><\/p>\n<p>Gene therapy is an emerging strategy to treat diseases caused by genetic abnormalities. One form of gene therapy involves the direct repair of a defective gene, using genome-editing technology such as CRISPR-Cas9. Despite its therapeutic potential, genome editing can also introduce unwanted and potentially harmful genetic errors that limit its clinical feasibility. In a study published in Genome Research, researchers centered at Osaka University report the use of a modified version of CRISPR-Cas9 that can edit genes with substantially fewer errors.<\/p>\n<p>CRISPR-Cas9 works through the combined action of the Cas9 protein, which cuts DNA, and a short guiding RNA (sgRNA), which tells Cas9 where to make the cut. Together, these two molecules allow virtually any gene in the genome to be targeted for editing. The greater challenge, though, is finding a way to make specific changes to a gene once it has been targeted.<\/p>\n<p>\u201cCas9 cleaves DNA on both of its strands, essentially splitting the target gene in two,\u201d principal investigator Shinichiro Nakada explains. \u201cThe cell tries to repair the damage by ligating the two pieces back together, but the end result is imprecise and often leaves unintended mutations.\u201d<\/p>\n<p>Cells have a precise form of repair that uses donor DNA as a template to correct damage. The template acts as a molecular blueprint, allowing the cell to repair DNA with much greater accuracy. Importantly, by giving cells a different blueprint\u2014in other words, by introducing foreign donor DNA into a cell\u2014highly accurate edits can be made to a defective gene.<\/p>\n<p>\u201cThe problem is that Cas9 cleavage is rarely repaired by the precise route,\u201d Nakada adds. \u201cWe instead used a modified Cas9 that only \u2018nicks\u2019 DNA in one strand, rather than cutting both strands. We discovered that when we nick both the target gene and donor DNA, we can essentially commandeer precise repair to make exact changes to the target gene.\u201d<\/p>\n<p>The researchers found that the nicking technique, which they term Single Nicking in the target Gene and Donor (SNGD), greatly suppresses the rate of unintended genetic mutation compared with the conventional method. In one experiment, the standard technique made potentially-harmful errors over 90% of the time, while SNGD did so less than 5% of the time. Importantly, this precision did not impair the overall performance of the approach, which was able to efficiently achieve the desired genetic edits.<\/p>\n<p>\u201cOur study is a proof of principle that target\u2013donor nicking can achieve accurate genome editing without DNA cleavage, which has significant implications for its use in medicine,\u201d Nakada notes. \u201cThere are many diseases for which a precise Cas9 system like this would make gene therapy more cost-effective and safer. We are very excited to see how this technique will be incorporated into the current paradigm of gene editing technologies.\u201d<\/p>\n<p>&nbsp;<\/p>\n<p><strong>The Article<\/strong>: \u201cPrecise and efficient nucleotide substitution near genomic nick via noncanonical homology-directed repair,\u201d was published in Genome Research at DOI: 10.1101\/gr.226027.117.<\/p>\n<p><strong>Summary<\/strong>:Gene therapy can potentially correct genetic disorders by directly editing defective genes. CRISPR-Cas9 is a popular gene-editing technology whose clinical utility is limited by its tendency to produce unintended genetic errors. Researchers centered at Osaka University developed a modified CRISPR-Cas9 system that uses single-stranded nicking, rather than DNA cleavage, to generate highly precise changes to a target gene. The technique offers a more accurate and safer editing strategy for future gene therapy applications.<\/p>\n<p><strong>Authors:<\/strong> Kazuhiro Nakajima, Yue Zhou, Akiko Tomita, Yoshihiro Hirade, Channabasavaiah B. Gurumurthy and Shinichiro Nakada<\/p>\n<p><strong>Journal:<\/strong> Genome Research<\/p>\n<p><strong>Article<\/strong>: \u201cPrecise and efficient nucleotide substitution near genomic nick via noncanonical homology-directed repair<\/p>\n<p><strong>DOI<\/strong>: 10.1101\/gr.226027.117<\/p>\n<p><strong>Funding<\/strong>: Japan Society for the Promotion of Science (JSPS) KAKENHI, Practical Research Project for Rare\/Intractable Diseases from Japan Agency for Medical Research and Development, Takeda Science Foundation, The Naito Foundation, The Sumitomo Foundation<\/p>\n<p><strong>Primary Keyword<\/strong>: Biology<\/p>\n<p><strong>Additional Keywords<\/strong>: Biotechnology, Cell Biology, Genetics, Gene Therapy, Molecular Biology<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Text in Japanese 2018-02-02 Publish Genome Research Researchers at Osaka University develop novel method that  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3513,"parent":3238,"menu_order":193,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/3507"}],"collection":[{"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/comments?post=3507"}],"version-history":[{"count":21,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/3507\/revisions"}],"predecessor-version":[{"id":7434,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/3507\/revisions\/7434"}],"up":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/3238"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/media\/3513"}],"wp:attachment":[{"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/media?parent=3507"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}