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Niinuma S, Wake Y, Nakagawa Y, Kaneko T. Importance of nuclear localization signal-fused Cas9 in the production of genome-edited mice via embryo electroporation. Biochem Biophys Res Commun 2023; 685:149140. [PMID: 37918326 DOI: 10.1016/j.bbrc.2023.149140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/09/2023] [Accepted: 10/19/2023] [Indexed: 11/04/2023]
Abstract
Previously, to generate genome-edited animals by introducing CRISPR-associated protein 9 (Cas9) into embryos, we developed the Technique for Animal Knockout system by Electroporation (TAKE). Additionally, by fluorescently labeling Cas9, we successfully visualized the Cas9 introduced into the pronuclei of embryos; however, whether Cas9 was introduced directly into the pronuclei by electric pulse or transferred from the cytoplasm by nuclear localization signal (NLS) remained unknown. Herein, we evaluated the localization of Cas9 with (Cas9-NLS) or without NLS (Cas9-noNLS) in mice embryos following electroporation by fusing them with GFP. Furthermore, we visually studied their effects on genome-editing rates in offspring by targeting tyrosinase gene. Fluorescence intensity in pronuclei of Cas9-NLS-electroporated embryos and genome-editing rates of offspring were significantly higher than those of Cas9-noNLS-electroporated embryos. Furthermore, fluorescence in Cas9-NLS-electroporated embryos in which pronuclei had not yet appeared 2.5 h after insemination was observed in the pronuclei of embryos appearing 3.5 h after electroporation. We demonstrated the effective transportation of Cas9 from the cytoplasm to pronuclei by the NLS following TAKE, which resulted in increased genome-editing rates in offspring. The TAKE along with fluorescently labeled nucleases can be used to verify nuclease delivery into individual embryos prior to embryo transfer for efficiently producing genome-edited animals.
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Affiliation(s)
- Sakura Niinuma
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Iwate, 020-8551, Japan
| | - Yui Wake
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Iwate, 020-8551, Japan
| | - Yuki Nakagawa
- Department of Chemistry and Biological Sciences, Faculty of Science and Engineering, Iwate University, Iwate, 020-8551, Japan
| | - Takehito Kaneko
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Iwate, 020-8551, Japan; Department of Chemistry and Biological Sciences, Faculty of Science and Engineering, Iwate University, Iwate, 020-8551, Japan.
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KOGASAKA Y, MURAKAMI S, YAMASHITA S, KIMURA D, FURUMOTO Y, IGUCHI K, SENDAI Y. Generation of germ cell-deficient pigs by NANOS3 knockout. J Reprod Dev 2022; 68:361-368. [PMID: 36273893 PMCID: PMC9792658 DOI: 10.1262/jrd.2022-028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
NANOS3 is an evolutionarily conserved gene expressed in primordial germ cells that is important for germ cell development. Germ cell deletion by NANOS3 knockout has been reported in several mammalian species, but its function in pigs is unclear. In the present study, we investigated the germline effects of NANOS3 knockout in pigs using CRISPR/Cas9. Embryo transfer of CRISPR/Cas9-modified embryos produced ten offspring, of which one showed wild-type NANOS3 alleles, eight had two mutant NANOS3 alleles, and the other exhibited mosaicism (four mutant alleles). Histological analysis revealed no germ cells in the testes or ovaries of any of the nine mutant pigs. These results demonstrated that NANOS3 is crucial for porcine germ cell production.
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Affiliation(s)
- Yuhei KOGASAKA
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Sho MURAKAMI
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Shiro YAMASHITA
- Quality Control Research Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Daisuke KIMURA
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Yoshinori FURUMOTO
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Kana IGUCHI
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
| | - Yutaka SENDAI
- Biological Sciences Section, Central Research Institute for Feed and Livestock, Zen-noh, Ibaraki 300-4204, Japan
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Navarro-Serna S, Dehesa-Etxebeste M, Piñeiro-Silva C, Romar R, Lopes JS, López de Munaín A, Gadea J. Generation of Calpain-3 knock-out porcine embryos by CRISPR-Cas9 electroporation and intracytoplasmic microinjection of oocytes before insemination. Theriogenology 2022; 186:175-184. [DOI: 10.1016/j.theriogenology.2022.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/17/2022] [Accepted: 04/19/2022] [Indexed: 01/31/2023]
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Navarro-Serna S, Piñeiro-Silva C, Luongo C, Parrington J, Romar R, Gadea J. Effect of Aphidicolin, a Reversible Inhibitor of Eukaryotic Nuclear DNA Replication, on the Production of Genetically Modified Porcine Embryos by CRISPR/Cas9. Int J Mol Sci 2022; 23:ijms23042135. [PMID: 35216252 PMCID: PMC8880323 DOI: 10.3390/ijms23042135] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 01/27/2023] Open
Abstract
Mosaicism is the most important limitation for one-step gene editing in embryos by CRISPR/Cas9 because cuts and repairs sometimes take place after the first DNA replication of the zygote. To try to minimize the risk of mosaicism, in this study a reversible DNA replication inhibitor was used after the release of CRISPR/Cas9 in the cell. There is no previous information on the use of aphidicolin in porcine embryos, so the reversible inhibition of DNA replication and the effect on embryo development of different concentrations of this drug was first evaluated. The effect of incubation with aphidicolin was tested with CRISPR/Cas9 at different concentrations and different delivery methodologies. As a result, the reversible inhibition of DNA replication was observed, and it was concentration dependent. An optimal concentration of 0.5 μM was established and used for subsequent experiments. Following the use of this drug with CRISPR/Cas9, a halving of mosaicism was observed together with a detrimental effect on embryo development. In conclusion, the use of reversible inhibition of DNA replication offers a way to reduce mosaicism. Nevertheless, due to the reduction in embryo development, it would be necessary to reach a balance for its use to be feasible.
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Affiliation(s)
- Sergio Navarro-Serna
- Department of Physiology, International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; (S.N.-S.); (C.P.-S.); (C.L.); (R.R.)
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain
| | - Celia Piñeiro-Silva
- Department of Physiology, International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; (S.N.-S.); (C.P.-S.); (C.L.); (R.R.)
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain
| | - Chiara Luongo
- Department of Physiology, International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; (S.N.-S.); (C.P.-S.); (C.L.); (R.R.)
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain
| | - John Parrington
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK;
| | - Raquel Romar
- Department of Physiology, International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; (S.N.-S.); (C.P.-S.); (C.L.); (R.R.)
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain
| | - Joaquín Gadea
- Department of Physiology, International Excellence Campus for Higher Education and Research “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; (S.N.-S.); (C.P.-S.); (C.L.); (R.R.)
- Institute for Biomedical Research of Murcia (IMIB-Arrixaca), 30120 Murcia, Spain
- Correspondence:
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Lin JC, Van Eenennaam AL. Electroporation-Mediated Genome Editing of Livestock Zygotes. Front Genet 2021; 12:648482. [PMID: 33927751 PMCID: PMC8078910 DOI: 10.3389/fgene.2021.648482] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
The introduction of genome editing reagents into mammalian zygotes has traditionally been accomplished by cytoplasmic or pronuclear microinjection. This time-consuming procedure requires expensive equipment and a high level of skill. Electroporation of zygotes offers a simplified and more streamlined approach to transfect mammalian zygotes. There are a number of studies examining the parameters used in electroporation of mouse and rat zygotes. Here, we review the electroporation conditions, timing, and success rates that have been reported for mice and rats, in addition to the few reports about livestock zygotes, specifically pigs and cattle. The introduction of editing reagents at, or soon after, fertilization can help reduce the rate of mosaicism, the presence of two of more genotypes in the cells of an individual; as can the introduction of nuclease proteins rather than mRNA encoding nucleases. Mosaicism is particularly problematic in large livestock species with long generation intervals as it can take years to obtain non-mosaic, homozygous offspring through breeding. Gene knockouts accomplished via the non-homologous end joining pathway have been more widely reported and successfully accomplished using electroporation than have gene knock-ins. Delivering large DNA plasmids into the zygote is hindered by the zona pellucida (ZP), and the majority of gene knock-ins accomplished by electroporation have been using short single stranded DNA (ssDNA) repair templates, typically less than 1 kb. The most promising approach to deliver larger donor repair templates of up to 4.9 kb along with genome editing reagents into zygotes, without using cytoplasmic injection, is to use recombinant adeno-associated viruses (rAAVs) in combination with electroporation. However, similar to other methods used to deliver clustered regularly interspaced palindromic repeat (CRISPR) genome-editing reagents, this approach is also associated with high levels of mosaicism. Recent developments complementing germline ablated individuals with edited germline-competent cells offer an approach to avoid mosaicism in the germline of genome edited founder lines. Even with electroporation-mediated delivery of genome editing reagents to mammalian zygotes, there remain additional chokepoints in the genome editing pipeline that currently hinder the scalable production of non-mosaic genome edited livestock.
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Affiliation(s)
- Jason C Lin
- Department of Animal Science, University of California, Davis, Davis, CA, United States
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Wake Y, Kaneko T. Production of genome-edited mice by visualization of nucleases introduced into the embryos using electroporation. J Reprod Dev 2020; 66:469-473. [PMID: 32713893 PMCID: PMC7593630 DOI: 10.1262/jrd.2020-068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/12/2020] [Indexed: 12/26/2022] Open
Abstract
Genome editing technology contributes to the quick and highly efficient production of genetically engineered animals. These animals are helpful in clarifying the mechanism of human disease. Recently, a new electroporation technique (TAKE: Technique for animal knockout system by electroporation) was developed to produce genome-edited animals by introducing nucleases into intact embryos using electroporation instead of the microinjection method. The aim of this study was to increase the efficiency of production of genome-edited animals using the TAKE method. In the conventional protocol, it was difficult to confirm the introduction of nucleases into embryos and energization during operation. Using only embryos that introduced nucleases for embryo transfer, it will lead to increased efficiency in the production of genome-edited animals. This study examined the visualization in the introduction of nucleases into the embryos by using nucleases fluorescent labeled with ATTO-550. The embryos were transfected with Cas9 protein and fluorescent labeled dual guide RNA (mixture with crRNA and tracrRNA with ATTO-550) targeted tyrosinase gene by the TAKE method. All embryos that survived after electroporation showed fluorescence. Of these embryos with fluorescence, 43.7% developed to morphologically normal offspring. In addition, 91.7% of offspring were edited by the tyrosinase gene. This study is the first to demonstrate that the introduction of nucleases into embryos by the TAKE method could be visualized using fluorescent-labeled nucleases. This improved TAKE method can be used to produce genome-edited animals and confirm energization during operation.
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Affiliation(s)
- Yui Wake
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Iwate 020-8551, Japan
| | - Takehito Kaneko
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Iwate 020-8551, Japan
- Department of Chemistry and Biological Sciences, Faculty of Science and Engineering, Iwate University, Iwate 020-8551, Japan
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