Details

Autor(en) / Beteiligte

• Murakami, Yu
• Futamata, Ryota
• Horibe, Tomohisa
• Ueda, Kazumitsu
• Kinoshita, Masato

Titel

CRISPR/Cas9 nickase‐mediated efficient and seamless knock‐in of lethal genes in the medaka fish Oryzias latipes

Ist Teil von

• Development, growth & differentiation, 2020-12, Vol.62 (9), p.554-567

Ort / Verlag

Japan: Wiley Subscription Services, Inc

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The CRISPR/Cas system offers new opportunities for targeted gene modifications in a wide range of organisms. In medaka (Oryzias latipes), a vertebrate model organism, a wild‐type Cas9‐based approach is commonly used to establish desired strains, however, its use in lethal genes is still challenging due to excess gene disruptions triggered by DNA double strand breaks (DSBs). To overcome this problem, we aimed to develop a new knock‐in system using Cas9 nickase (Cas9n) that can reduce DNA DSBs. We revealed that Cas9n allowed reduction of the DSB‐induced unwanted mutagenesis via non‐homologous end‐joining at both on‐ and off‐ target sites. Further, with a new donor plasmid (p2BaitD) that provides a linear template through Cas9n‐mediated nicks, we successfully integrated reporter cassettes via homology‐directed repair (HDR) into all three loci tested, including a lethal gene. In the experiment targeting the lethal gene, the combination of p2BaitD and Cas9n achieved higher survival rates than the Cas9‐based approach, which enabled the desired knock‐in founders. Additionally, through a technical blend of our knock‐in system with a recently developed One‐step mating protocol, we successfully established a homozygous knock‐in strain in one generation period. This study presents evidence of an effective method to generate an HDR‐mediated gene knock‐in in medaka and other organisms, which is useful for establishing screening platforms for genes or drugs toxicity or other applications. We revealed that Cas9n allowed remarkable reduction of the DSB‐induced unwanted mutagenesis via non‐homologous end‐joining at both on‐ and off‐target sites. Additionally, we achieved an efficient knock‐in via homology‐directed repair (HDR) at all three loci tested, including a lethal gene. Further, with a new donor plasmid (p2BaitD) that provides a linear template through Cas9n‐mediated nicks, we boosted the knock‐in efficiency in medaka embryos and established a homozygous knock‐in strain in one generation period.