Vitrification of Pronuclear Zygotes Perturbs Porcine Zygotic Genome Activation

Abstract

Zygotic genome activation (ZGA) plays an essential role in early embryonic development. Vitrification is a common assisted reproductive technology that frequently reduces the developmental competence of embryos. However, the effect of vitrification on porcine ZGA and gene expression during ZGA remains largely unclear. Here, we found that vitrification of pronuclear zygotes derived from parthenogenetic activation (PA) and in vitro fertilization (IVF) resulted in a significant reduction in the rates of 2-cell, 4-cell, and blastocysts, but did not affect the quality of blastocysts. Functional research revealed that RNA polymerase II Inhibitor (α-amanitin) treatment significantly reduced global transcriptional activity and developmental efficiency of both 4-cell and 8-cell embryos, implying an essential role of ZGA in porcine early embryonic development. Furthermore, vitrification did not affect the synthesis of nascent mRNA of 2-cell embryos, but significantly inhibited global transcriptional activity of both 4-cell and 8-cell embryos, suggesting an impaired effect of vitrification on porcine ZGA. Correspondingly, the single-cell analysis showed that vitrification caused the downregulation or upregulation expression of maternal genes in 4-cell embryos, also significantly decreased the expression of zygotic genes. Taken together, these results indicated that vitrification of pronuclear zygotes impairs porcine zygotic genome activation.

The walnut-derived peptide TW-7 improves mouse parthenogenetic embryo development of vitrified MII oocytes potentially by promoting histone lactylation

“…Lactate deprivation resulted in H3K18la loss, thus causing major ZGA failure and 2-cell embryo development arrest in mice and humans [ 36 ]. Besides, the vitrification of porcine zygotes significantly reduced the transcriptional activity of the ZGA genes in 4-cell and 8-cell embryos [ 72 ]. Therefore, we hypothesized that vitrification may down-regulate histone lactylation, and then repress ZGA gene transcription and consequently hamper the embryo development.…”

Zygote cryobanking applied to CRISPR/Cas9 microinjection in mice

“…The developmental stage at which embryos are vitrified has an important effect on post-warming developmental capacity. Impaired blastocyst formation has been reported in mouse [ 28 , 29 ], pig [ 30 ], rabbit [ 31 ] and cow [ 32 ] vitrified zygotes. An increased blastocyst development can be achieved when morulae are subjected to vitrification [ 28 , 33 ].…”

An Interplay between Epigenetics and Translation in Oocyte Maturation and Embryo Development: Assisted Reproduction Perspective

“…Vitrification of bovine oocytes was associated with a significant reduction in the expression profile of three epigenetic-related genes DNMT1, DNMT3B, and HDAC1 [ 252 ]. In vitrified porcine embryos, a greatly reduced expression of epigenetically associated key genes SMYD3, TET2, and HDAC8 led to altered epigenetic reprogramming and decreased blastocyst rates [ 253 ]. The cryoprotective agents present in IVF vitrification media might negatively affect the epigenetic profile in embryos, as dimethylsulfoxide (DMSO) was found to be responsible for the disruption of global DNA methylation and significant decrease of ATP content in vitrified human cardiac tissue [ 254 ].…”