Triple gene editing in porcine embryos using electroporation alone or in combination with microinjection

Vet World Vol.15 February-2022 Article-33

Research Article

Veterinary World, 15(2): 496-501

https://doi.org/10.14202/vetworld.2022.496-501

Zhao Namula^1,2, Quynh Anh Le^1,3, Manita Wittayarat^1,3, Qingyi Lin^1,3, Koki Takebayashi^1,3, Maki Hirata^1,3, Lanh Thi Kim Do^3,4, Fuminori Tanihara^3,5, and Takeshige Otoi^1,2

1. Bio-Innovation Research Center, Tokushima University, 7793233 Tokushima, Japan.
2. Department of Veterinary Medicine, College of Coastal Agricultural Sciences, Guangdong Ocean University, 524088 Guangdong, China.
3. Laboratory of Animal Reproduction, Faculty of Bioscience and Bioindustry, Tokushima University, 7793233 Tokushima, Japan.
4. Department of Animal Theriogenology and Surgery, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, 100000 Hanoi, Vietnam.
5. Center for Development of Advanced Medical Technology, Jichi Medical University, 3290498 Tochigi, Japan.

Background and Aim: We previously developed the gene-editing by electroporation (EP) of Cas9 protein method, in which the CRISPR/Cas9 system was introduced into porcine in vitro fertilized (IVF) zygotes through EP to disrupt a target gene. This method should be further developed, and a combination of EP and MI methods should be evaluated in pigs. This study aimed to determine that a combination of microinjection (MI) and EP of CRISPR/Cas9 system could increase the rates of biallelic mutation for triple-gene knockout in porcine blastocysts. We targeted the pancreatic and duodenal homeobox1 (PDX1) gene using cytoplasmic MI 1 h before or after EP, which was used to edit alpha-1,3-galactosyltransferase (GGTA1) and cytidine 32 monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) genes in porcine zygotes.

Materials and Methods: We introduced guide RNAs targeting PDX1, GGTA1, and CMAH with the Cas9 protein into IVF zygotes (one-cell stage) through EP 10 h after the start of IVF (IVF; EP group) or in combination with MI (1 h before, MI-EP group, or after EP treatment EP-MI group) and evaluated the blastocyst formation rate and efficiency of target mutations in the resulting blastocysts.

Results: Our results revealed a significant reduction in the rate of blastocyst formation in the two groups that underwent MI before and after EP (MI-EP and EP-MI group), compared with that in the groups treated with EP alone (EP group) (p=0.0224 and p<0.0001, respectively) and control (p=0.0029 and p<0.0001, respectively). There was no significant difference in the total mutation rates among the treatment groups in the resulting blastocysts. As an only positive effect of additional MI treatment, the rate of blastocysts carrying biallelic mutations in at least one target gene was higher in the MI-EP group than in the EP group. However, there was no difference in the rates of embryos carrying biallelic mutations in more than 2 target genes.

Conclusion: These results indicate that although a combination of MI and EP does not improve the mutation efficiency or biallelic mutation for triple-gene knockout, MI treatment before EP is better to reduce mortality in porcine zygotic gene editing through a combination of MI and EP. Keywords: clustered regularly interspaced short palindromic repeats/Cas9, electroporation, gene editing, microinjection, porcine zygotes.

Keywords: clustered regularly interspaced short palindromic repeats/Cas9, electroporation, gene editing, microinjection, porcine zygotes.

How to cite this article: Namula Z, Le QA, Wittayarat M, Lin Q, Takebayashi K, Hirata M, Do LTK, Tanihara F, Otoi T (2022) Triple gene editing in porcine embryos using electroporation alone or in combination with microinjection, Veterinary World, 15(2): 496-501.

Received: 08-12-2021 Accepted: 27-01-2022 Published online: 27-02-2022

Corresponding author: Fuminori Tanihara E-mail: f_tanihara@jichi.ac.jp

DOI: 10.14202/vetworld.2022.496-501

Copyright: Namula, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.