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Creation of CRISPR-based germline-genome-engineered mice without ex vivo handling of zygotes by i-GONAD
- Source :
- Nature Protocols. 14:2452-2482
- Publication Year :
- 2019
- Publisher :
- Springer Science and Business Media LLC, 2019.
-
Abstract
- Methods to create genetically engineered mice involve three major steps: harvesting embryos from one set of females, microinjection of reagents into embryos ex vivo and their surgical transfer to another set of females. Although tedious, these methods have been used for more than three decades to create mouse models. We recently developed a method named GONAD (genome editing via oviductal nucleic acids delivery), which bypasses these steps. GONAD involves injection of CRISPR components (Cas9 mRNA and guide RNA (gRNA)) into the oviducts of pregnant females 1.5 d post conception, followed by in vivo electroporation to deliver the components into the zygotes in situ. Using GONAD, we demonstrated that target genes can be disrupted and analyzed at different stages of mouse embryonic development. Subsequently, we developed improved GONAD (i-GONAD) by delivering CRISPR ribonucleoproteins (RNPs; Cas9 protein or Cpf1 protein and gRNA) into day-0.7 pregnant mice, which made it suitable for routine generation of knockout and large-deletion mouse models. i-GONAD can also generate knock-in models containing up to 1-kb inserts when single-stranded DNA (ssDNA) repair templates are supplied. i-GONAD offers other advantages: it does not require vasectomized males and pseudo-pregnant females, the females used for i-GONAD are not sacrificed and can be used for other experiments, it can be easily adopted in laboratories lacking sophisticated microinjection equipment, and can be implemented by researchers skilled in small-animal surgery but lacking embryo-handling skills. Here, we provide a step-by-step protocol for establishing the i-GONAD method. The protocol takes ∼6 weeks to generate the founder mice. This protocol describes procedures for generating genome-edited mouse models by injecting CRISPR reagents into oviducts of pregnant females and subsequently electroporating the reagents into zygotes in situ, thus bypassing cumbersome ex vivo handling of embryos.
- Subjects :
- endocrine system
0303 health sciences
Zygote
Gonad
Cas9
Electroporation
Biology
General Biochemistry, Genetics and Molecular Biology
Cell biology
03 medical and health sciences
0302 clinical medicine
medicine.anatomical_structure
Genome editing
medicine
CRISPR
Guide RNA
030217 neurology & neurosurgery
Ex vivo
030304 developmental biology
Subjects
Details
- ISSN :
- 17502799 and 17542189
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Nature Protocols
- Accession number :
- edsair.doi...........441ac14f60302ed632a088eb86af41c3