{"id":8000,"date":"2023-09-15T18:19:01","date_gmt":"2023-09-15T09:19:01","guid":{"rendered":"https:\/\/www.med.osaka-u.ac.jp\/eng\/?page_id=8000"},"modified":"2023-09-19T09:49:41","modified_gmt":"2023-09-19T00:49:41","slug":"snakata2023-9-15","status":"publish","type":"page","link":"https:\/\/www.med.osaka-u.ac.jp\/eng\/activities\/results\/2023year\/snakata2023-9-15","title":{"rendered":"Akiko Tomita, Shinichirou Nakada \u226aBioregulation and Cellular Response\u226b <span>A NICER approach to genome editing<\/span>"},"content":{"rendered":"<ul class=\"linkBar clearfix\">\n<li><a href=\"https:\/\/www.med.osaka-u.ac.jp\/activities\/results\/2023year\/snakata2023-9-15\">Text in Japanese<\/a><\/li>\n<\/ul>\n<p>Nature Communications<\/p>\n<p>Researchers led by Osaka University develop a new gene modification technique known as NICER that significantly reduces off-target mutations in DNA<\/p>\n<p class=\"figure\"><a href=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8002 size-medium\" src=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig1-400x248.png?_t=1694577939\" alt=\"\" width=\"400\" height=\"248\" srcset=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig1-400x248.png 400w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig1-768x477.png 768w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig1.png 900w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><\/a><br \/>Figure 1. Off-target mutations resulting from conventional genome editing methods. <br \/>Due to the mutagenic nature of DNA double-strand break repair, even if the gene mutation is successfully corrected, there is a heightened risk of off-target mutations in areas distinct from the original target of CRISPR\/Cas9.<\/p>\n<div class=\"TextBlock\">\n<p>The gene editing technique CRISPR\/Cas9 has allowed researchers to make precise and impactful changes to an organism\u2019s DNA to fix mutations that cause genetic disease. However, the CRISPR\/Cas9 method can also result in unintended DNA mutations that may have negative effects. Recently, researchers in Japan have developed a new gene editing technique that is as effective as CRISPR\/Cas9 while \u00a0significantly reducing these unintended mutations.<\/p>\n<p>In a new study published in <em>Nature Communications<\/em>, researchers led by Osaka University introduced a novel technique called NICER, which is based on the creation of multiple small cuts in single DNA strands by an enzyme called a nickase.<\/p>\n<p>Traditional CRISPR\/Cas9 editing uses small pieces of genetic code called guide RNAs and an enzyme called Cas9. The guide RNAs target a specific section of the DNA and the Cas9 enzyme initiates a break in the double-stranded DNA structure at this location. This double-strand break is key for initiating changes to the DNA. However, cellular repair of double-strand breaks can lead to unintended DNA mutations, as well as the integration of exogenous DNA to the human genome, which raises safety concerns for clinical applications of CRISPR\/Cas9 technology. To minimize these unintended mutations, the Osaka University-led research team investigated the use of Cas9 nickase, which creates single-strand breaks or \u201cnicks\u201d in DNA that are typically repaired without causing mutations.\u00a0<\/p>\n<p>\u201cEach chromosome in the genome has a \u2018homologous\u2019 copy,\u201d says lead author of the study Akiko Tomita. \u201cUsing the NICER technique, heterozygous mutations \u2013 in which a mutation appears in one chromosome but not its homologous copy \u2013 are repaired using the unmutated homologous chromosome as a template.\u201d<\/p>\n<p>For their initial experiments, the research team used human lymphoblast cells with a known heterozygous mutation in a gene called TK1. When these cells were treated with nickase to induce a single cut in the TK1 region, TK1 activity was recovered at a low rate. However, when the nickase induced multiple nicks in this region on both homologous chromosomes, gene correction efficiency was enhanced approximately seventeen-fold via activation of a cellular repair mechanism.<\/p>\n<p>\u201cFurther genomic analysis showed that the NICER technique rarely induced off-target mutations,\u201d says senior author Shinichiro Nakada. \u201cWe were also pleased to find that NICER was able to restore the expression of disease-causing genes in cells derived from genetic diseases involving compound heterozygous mutations.\u201d<\/p>\n<p>Because the NICER method does not involve DNA double-strand breaks or the use of exogenous DNA, this technique appears to be a safe alternative to conventional CRISPR\/Cas9 methods. NICER may represent a novel approach for the treatment of genetic diseases caused by heterozygous mutations.<\/p>\n<\/div>\n<p>###<\/p>\n<p>The article, \u201cInducing multiple nicks promotes interhomolog homologous recombination to correct heterozygous mutations in somatic cells,\u201d will be published in <em>Nature Communications<\/em> at DOI: <a href=\"https:\/\/doi.org\/10.1038\/s41467-023-41048-5\">https:\/\/doi.org\/10.1038\/s41467-023-41048-5<\/a>.<\/p>\n<p><strong>Summary:<\/strong> Researchers led by Osaka University developed a novel genome editing technique known as NICER, which results in significantly fewer off-target mutations than CRISPR\/Cas9 editing. The technique uses a different type of enzyme that makes single-stranded \u201cnicks\u201d in the DNA. Repair of these nicks is more efficient and accurate than repair of double-strand breaks caused by the current CRISPR\/Cas9 editing. This technique represents a novel approach for the treatment of genetic diseases caused by heterozygous mutations.<\/p>\n<p><strong>Tweet 1<\/strong>: Researchers develop #NICER approach to #genome editing that significantly reduces off-target #mutations<br \/>@osaka_univ_e<\/p>\n<p><strong>Tweet 2<\/strong>: Researchers led by Osaka University improve CRISPR genome editing and reduce off-target mutations<\/p>\n<p><strong>Primary Keyword<\/strong>: Health and medicine<br \/><strong>Additional Keywords<\/strong>: Genome Editing, Targeted Genome Editing, CRISPRs, Genomic DNA, Chromosomes, Double Strand Breaks, Mutation, Genetic Disorders<\/p>\n<p><strong>Method of Research<\/strong>: Experimental study<\/p>\n<p><strong>Subject of Research<\/strong>: Lab-produced tissue samples<\/p>\n<p class=\"figure\"><a href=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig2.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8004 size-medium\" src=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig2-400x275.png?_t=1694577972\" alt=\"\" width=\"400\" height=\"275\" srcset=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig2-400x275.png 400w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig2-768x527.png 768w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig2.png 900w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><\/a><br \/>Figure 2. Genome editing using the Cas9 mutant, nickase.<br \/>Nickase induces single-strand breaks (nicks) instead of DNA double-strand breaks. Nicks are typically repaired without causing mutations. Hence, even if nicks appear at sites different from nickase&#8217;s original target, new gene mutations are seldom seen at these locations. This approach allows for precise gene correction with minimal off-target mutations.<\/p>\n<p class=\"figure\"><a href=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig3.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-8003 size-medium\" src=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig3-400x243.png?_t=1694577988\" alt=\"\" width=\"400\" height=\"243\" srcset=\"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig3-400x243.png 400w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig3-768x467.png 768w, https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-content\/uploads\/2023\/09\/nkata_efig3.png 900w\" sizes=\"(max-width: 400px) 100vw, 400px\" \/><\/a><br \/>Figure 3. Schematic of the NICER gene editing method. <br \/>A nick is made near the mutation (and is exclusive to the mutant allele). Merely introducing a nick close to the mutation instigates homologous recombination between homologous chromosomes but at a very low rate. However, when one or two additional nicks are made to both alleles, the gene correction efficiency through interhomolog homologous recombination sees a significant boost.<\/p>\n<div class=\"TextBlock\">\n<p>Title: \u201cInducing multiple nicks promotes interhomolog homologous recombination to correct heterozygous mutations in somatic cells\u201d<\/p>\n<\/div>\n<p>Journal: <em>Nature Communications<\/em><em><br \/><\/em>Authors: Akiko Tomita, Hiroyuki Sasanuma, Tomoo Owa, Yuka Nakazawa, Mayuko Shimada, Takahiro Fukuoka, Tomoo Ogi &amp; Shinichiro Nakada<br \/>DOI: <a href=\"https:\/\/doi.org\/10.1038\/S41467-023-41048-5\">10.1038\/S41467-023-41048-5<\/a><\/p>\n<p>Funded by:<\/p>\n<p>Ministry of Education, Culture, Sports, Science and Technology<br \/>Japan Agency for Medical Research and Development<br \/>The Uehara Memorial Foundation<br \/>Takeda Science Foundation<br \/>Ichiro Kanehara Foundation<br \/>The Mother and Child Health Foundation<br \/>Princess Takamatsu Cancer Research Fund<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Text in Japanese Nature Communications Researchers led by Osaka University develop a new gene modification tec [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":8003,"parent":7833,"menu_order":43,"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\/8000"}],"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=8000"}],"version-history":[{"count":5,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/8000\/revisions"}],"predecessor-version":[{"id":8010,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/8000\/revisions\/8010"}],"up":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/pages\/7833"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/media\/8003"}],"wp:attachment":[{"href":"https:\/\/www.med.osaka-u.ac.jp\/eng\/wp-json\/wp\/v2\/media?parent=8000"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}