TY - JOUR
T1 - Genetic Manipulation of the Equine Oocyte and Embryo
AU - Hisey, Erin A.
AU - Ross, Pablo J.
AU - Meyers, Stuart
N1 - Funding Information:
The authors would like to thank the Students Training in Academic Research (STAR) Program for providing financial support for EAH through the UC Davis School of Veterinary Medicine Endowment Fund.
Publisher Copyright:
© 2021 Elsevier Inc.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/4
Y1 - 2021/4
N2 - As standard in vitro fertilization is not a viable technique in horses yet, many different techniques have been used to create equine embryos for research purposes. One such method is parthenogenesis in which an oocyte is induced to mature into an embryo-like state without the introduction of a spermatozoon, and thus they are not considered true embryos. Another method is somatic cell nuclear transfer (SCNT), in which a somatic cell nucleus from an extant horse is inserted into an enucleated oocyte, creating a genetic clone of the donor horse. Due to limited availability of equine oocytes in the United States, researchers have investigated the potential for combining equine somatic cell nuclei with oocytes from other species to make embryos for research purposes, which has not been successful to date. There has also been a rising interest in producing transgenic animals using sperm exposed to exogenous DNA. The successful creation of transgenic equine blastocysts shows the promise of sperm mediated gene transfer (SMGT), but this method is not ideal for other applications, like gene therapy, because it cannot be used to induce targeted mutations. That is why technologies like CRISPR/Cas9 are vital. In this review, we argue that parthenogenesis, SCNT, and interspecies SCNT can be considered genetic manipulation strategies as they create embryos that are genetically identical to their parent cell. Here, we describe how these methods are performed and their applications and we also describe the few methods that have been used to directly modify equine embryos: SMGT and CRISPR/Cas9.
AB - As standard in vitro fertilization is not a viable technique in horses yet, many different techniques have been used to create equine embryos for research purposes. One such method is parthenogenesis in which an oocyte is induced to mature into an embryo-like state without the introduction of a spermatozoon, and thus they are not considered true embryos. Another method is somatic cell nuclear transfer (SCNT), in which a somatic cell nucleus from an extant horse is inserted into an enucleated oocyte, creating a genetic clone of the donor horse. Due to limited availability of equine oocytes in the United States, researchers have investigated the potential for combining equine somatic cell nuclei with oocytes from other species to make embryos for research purposes, which has not been successful to date. There has also been a rising interest in producing transgenic animals using sperm exposed to exogenous DNA. The successful creation of transgenic equine blastocysts shows the promise of sperm mediated gene transfer (SMGT), but this method is not ideal for other applications, like gene therapy, because it cannot be used to induce targeted mutations. That is why technologies like CRISPR/Cas9 are vital. In this review, we argue that parthenogenesis, SCNT, and interspecies SCNT can be considered genetic manipulation strategies as they create embryos that are genetically identical to their parent cell. Here, we describe how these methods are performed and their applications and we also describe the few methods that have been used to directly modify equine embryos: SMGT and CRISPR/Cas9.
KW - CRISPR/Cas9
KW - Embryo
KW - Equine
KW - Parthenogenesis
KW - Somatic cell nuclear transfer
KW - Sperm mediated gene transfer
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U2 - 10.1016/j.jevs.2021.103394
DO - 10.1016/j.jevs.2021.103394
M3 - Review article
C2 - 33781418
AN - SCOPUS:85102033220
VL - 99
JO - Journal of Equine Veterinary Science
JF - Journal of Equine Veterinary Science
SN - 0737-0806
M1 - 103394
ER -