Successful <i>i</i>-GONAD in Mice at Early Zygote Stage through In Vivo Electroporation Three Min after Intraoviductal Instillation of CRISPR-Ribonucleoprotein
Improved genome editing via oviductal nucleic acids delivery (<i>i</i>-GONAD) is a new technology enabling in situ genome editing of mammalian zygotes exiting the oviductal lumen, which is now available in mice, rats, and hamsters. In this method, CRISPR/Cas9 genome-editing reagents are...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-09-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/18/10678 |
| Summary: | Improved genome editing via oviductal nucleic acids delivery (<i>i</i>-GONAD) is a new technology enabling in situ genome editing of mammalian zygotes exiting the oviductal lumen, which is now available in mice, rats, and hamsters. In this method, CRISPR/Cas9 genome-editing reagents are delivered directly to the oviducts of pregnant animals (corresponding to late zygote stage). After intraoviductal instillation, electric shock to the entire oviduct was provided with a specialized electroporation (EP) device to drive the genome editing reagents into the zygotes present in the oviductal lumen. <i>i</i>-GONAD toward early zygotes has been recognized as difficult, because they are tightly surrounded by a cumulus cell layer, which often hampers effective transfer of nucleic acids to zygotes. However, in vivo EP three min after intraoviductal instillation of the genome-editing reagents enabled genome editing of early zygotes with an efficiency of 70%, which was in contrast with the rate of 18% when in vivo EP was performed immediately after intraoviductal instillation at Day 0.5 of pregnancy (corresponding to 13:00–13:30 p.m. on the day when vaginal plug was recognized after natural mating). We also found that addition of hyaluronidase, an enzyme capable of removing cumulus cells from a zygote, slightly enhanced the efficiency of genome editing in early zygotes. These findings suggest that cumulus cells surrounding a zygote can be a barrier for efficient generation of genome-edited mouse embryos and indicate that a three-minute interval before in vivo EP is effective for achieving <i>i</i>-GONAD-mediated genome editing at the early zygote stage. These results are particularly beneficial for researchers who want to perform genome editing experiments targeting early zygotes. |
|---|---|
| ISSN: | 1661-6596 1422-0067 |