CRISPR/Cas9-Mediated Biallelic Knockout of IRX3 Reduces the Production and Survival of Somatic Cell-Cloned Bama Minipigs

Xiangxing Zhu; Yanyan Wei; Qunmei Zhan; Aifen Yan; Juan Feng; Lian Liu; Dongsheng Tang

doi:10.3390/ani10030501

CRISPR/Cas9-Mediated Biallelic Knockout of IRX3 Reduces the Production and Survival of Somatic Cell-Cloned Bama Minipigs

Animals (Basel). 2020 Mar 17;10(3):501. doi: 10.3390/ani10030501.

Authors

Xiangxing Zhu¹, Yanyan Wei², Qunmei Zhan², Aifen Yan^{1

2}, Juan Feng¹, Lian Liu¹, Dongsheng Tang^{1

2}

Affiliations

¹ Guangdong Provincial Engineering and Technology Research Center for Gene Editing, School of Medical Engineering, Foshan University, Foshan 528225, China.
² Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, School of Life Science and Engineering, Foshan University, Foshan 528225, China.

Abstract

Bama minipigs are a local pig breed that is unique to China and has a high development and utilization value. However, its high fat content, low feed utilization rate, and slow growth rate have limited its popularity and utilization. Compared with the long breeding cycle and high cost of traditional genetic breeding of pigs, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) endonuclease 9 system (CRISPR/Cas9)-mediated gene editing can cost-effectively implement targeted mutations in animal genomes, thereby providing a powerful tool for rapid improvement of the economic traits of Bama minipigs. The iroquois homeobox 3 (IRX3) gene has been implicated in human obesity. Mouse experiments have shown that knocking out IRX3 significantly enhances basal metabolism, reduces fat content, and controls body mass and composition. This study aimed to knock out IRX3 using the CRISPR/Cas9 gene editing method to breed Bama minipigs with significantly reduced fat content. First, the CRISPR/Cas9 gene editing method was used to efficiently obtain IRX3^-/- cells. Then, the gene-edited cells were used as donor cells to produce surviving IRX3^-/- Bama minipigs using somatic cell cloning. The results show that the use of IRX3^-/- cells as donor cells for the production of somatic cell-cloned pigs results in a significant decrease in the average live litter size and a significant increase in the average number of stillbirths. Moreover, the birth weight of surviving IRX3^-/- somatic cell-cloned pigs is significantly lower, and viability is poor such that all piglets die shortly after birth. Therefore, the preliminary results of this study suggest that IRX3 may have important biological functions in pigs, and IRX3 should not be used as a gene editing target to reduce fat content in Bama minipigs. Moreover, this study shows that knocking out IRX3 does not favor the survival of pigs, and whether targeted regulation of IRX3 in the treatment of human obesity will also induce severe adverse consequences requires further investigation.

Keywords: Bama minipig; CRISPR/Cas9-mediated gene editing; Iroquois homeobox 3 (IRX3); obesity; somatic cell cloning.

Abstract

Grants and funding