State of the art of nuclear transfer technologies for assisting mammalian reproduction

Abstract

The transfer of nuclear genomic DNA from a cell to a previously enucleated oocyte or zygote constitutes one of the main tools for studying epigenetic reprogramming, nucleus-cytoplasm compatibility, pluripotency state, and for genetic preservation or edition in animals. More than 50 years ago, the first experiences in nuclear transfer began to reveal that factors stored in the cytoplasm of oocytes could reprogram the nucleus of another cell and support the development of an embryo with new genetic information. Furthermore, when the nuclear donor cell is an oocyte, egg, or a zygote, the implementation of these technologies acquires clinical relevance for patients with repeated failures in ART associated with poor oocyte quality or mitochondrial dysfunctions. This review describes the current state, scope, and future perspectives of nuclear transfer techniques currently available for assisting mammal reproduction.

Preimplantation Developmental Competence of Bovine and Porcine Oocytes Activated by Zinc Chelation

“…Moreover, it is an essential step in SCNT and for assisting round spermatid sperm injection. Interestingly, despite the recent advances in the area, the efficiency of SCNT in terms of healthy newborns in mammalian species is still very low, and a better oocyte activation protocol could improve cloning efficiency [ 16 ]. While IVF has been performed successfully in bovine, [ 30 ], ICSI bovine and porcine embryos fail to develop in vitro, and low blastocyst rates are obtained [ 31 ].…”

“…Artificial-induced oocyte activation has a crucial impact on the production of somatic cell nuclear transfer (SCNT) embryos [ 16 ] and for assisting oocyte activation when this phenomenon is not properly triggered by the sperm upon fertilization. Altered sperm-induced Ca signaling at fertilization compromises the blastocyst transcriptome [ 17 ], preimplantation, and post-implantation development [ 18 ], possibly altering epigenetic events and the expression of key cell differentiation transcription factors [ 19 , 20 ].…”

Conservation Mitonuclear Replacement: Facilitated mitochondrial adaptation for a changing world

“…Both iSCNT and MRT involve the transfer of nuclear chromosomes into enucleated cells to create a chimeric embryo. In conservation, iSCNT has long been pursued as a method to clone endangered or extinct species from frozen cell lines by transferring the somatic nucleus of one species into the cytoplasm of a closely‐related species' egg cell (Bolton et al., 2022 ; Gambini et al., 2022 ; Loi et al., 2011 ; Mastromonaco et al., 2014 ). While interspecific cloning has often been unsuccessful, a large degree of the difficulty derives from mitonuclear incompatibility between donor and recipient (Dobler et al., 2014 ; Loi et al., 2011 ; Mastromonaco et al., 2007 ; Wisely et al., 2015 and references therein).…”

Comparison between concentration and type of intracellular cryoprotectants and the presence of sucrose for cryobanks of somatic cells derived from captive Pumas

“…In 2021, the birth of a black‐footed ferret ( Mustela nigripes ) produced by the interspecific somatic cell nuclear transfer (iSCNT) was reported from cells preserved for 30 years (US Fish and Wildlife Service, 2021). These are clear examples of how iSCNT and cryobanks of somatic cells are currently being used to preserve endangered genetics, increase genetic variability in animal populations, and restore genomes lost years ago (Gambini et al, 2022).…”