Genome‐editing technologies to improve research, reproduction, and production in pigs

Abstract

The ability to directly manipulate the pig genome through genetic engineering has been available to the research community for over three decades. This technology has progressed from the random insertion of foreign DNA, via a variety of techniques (pronuclear microinjection, sperm mediated gene transfer, and integration of mobile genetic elements), to manipulation of endogenous genes, via homologous recombination in somatic cells followed by somatic cell nuclear transfer. Over the last few years, designer nucleases facilitated the development of techniques that provide efficient ways to introduce foreign DNA or to modify endogenous genes in eggs, zygotes, or somatic cells. Together, these genome-editing technologies have essentially removed the obstacles to gene manipulation in swine. Although the regulatory environment is still unclear for agricultural applications, genetic engineering of pigs will continue to advance biomedicine and biology. In addition, genetic engineering is now sufficiently simple and efficient that agricultural research can now ask basic and applied questions that are not hampered by limited funding.

Allograft Inflammatory Factor 1 as an Immunohistochemical Marker for Macrophages in Multiple Tissues and Laboratory Animal Species

“…With the ever-widening application of genetically modified mice and other laboratory animal species, it is increasingly useful to have validated immunohistochemical markers for humans that function across laboratory animal species. 40,50 Mice likely will continue to be used extensively in translational research, because they provide a wide range of genetic models, have a short life span and high reproductive fecundity, and are inexpensive to house. However, some of the challenges and pitfalls in translating mouse research studies to humans have garnered increased attention recently.…”

Epigenetic Reprogramming During Somatic Cell Nuclear Transfer: Recent Progress and Future Directions

“…In agriculture, SCNT can rescue endangered species, protect the genetic resources of commercially important species, and accelerate the propagation of breeding livestock, including pigs, cows, and sheep (Gomez et al, 2009;Keefer, 2015). In combination with genome-modification technologies such as the recently developed clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9mediated genome editing, SCNT can rapidly produce cloned mammals with desirable traits including rapid growth, disease resistance, and good meat quality, thereby cultivating novel varieties, and shortening breeding cycle (Galli et al, 2012;Wells and Prather, 2017;Lee et al, 2020). In biomedicine, SCNT can create a mammary gland bioreactor to produce therapeutic proteins, establish animal models to investigate the pathogenesis of human diseases, and produce genetically modified xenograft organs for patient transplantation (Lotti et al, 2017;Niu et al, 2017;Telugu et al, 2017).…”

Genome Engineering for Xenotransplantation

“…The deliberate introduction of double-stranded DNA breaks at the desired integration site should therefore improve the efficiency of heterologous DNA insertion by activating and recruiting the cellular repair machinery. Application of ZFN, TALEN and CRISPR technologies have shown that homologous recombination efficiencies are improved when one or more doublestrand DNA breaks are introduced into the genome at the desired site of insertion [67] with CRISPR exhibiting bi-allelic targeting rates as high as 90% [68]. The use of these more advanced genome engineering tools has greatly improved the rates and specificity of both gene deletion and gene insertion in genomes.…”