Ratio of the zygote cytoplasm to the paternal genome affects the reprogramming and developmental efficiency of androgenetic embryos

Abstract

Uniparental embryos have uniparental genomes and are very useful models for studying the specific gene expression of parents or for exploring the biological significance of genomic imprinting in mammals. However, the early developmental efficiency of androgenetic embryos is significantly lower than that of parthenogenetic embryos. In addition, oocytes are able to reprogram sperm nuclei after fertilization to guarantee embryonic development by maternally derived reprogramming factors, which accumulate during oogenesis. However, the importance of maternal material in the efficiency of reprogramming the pronucleus of androgenetic embryos is not known. In this study, androgenetic embryos were constructed artificially by pronucleus transfer (PT) or double sperm injection (DS). Compared with DS embryos, PT embryos that were derived from two zygotes contained more maternal material, like 10-11 translocation methylcytosine deoxygenase 3 (Tet3) and histone variant 3.3 (H3.3). Our experiments confirmed the better developmental potential of PT embryos, which had higher blastocyst rates, a stronger expression of pluripotent genes, a lower expression of apoptotic genes, and superior blastocyst quality. Our findings indicate that the aggregation of more maternal materials in the paternal pronucleus facilitate the reprogramming of the paternal genome, improving embryonic development in PT androgenesis. K E Y W O R D Sandrogenetic embryos, maternal materials, paternal pronucleus, reprogramming

Short-interval second ejaculation improves sperm quality, blastocyst formation in oligoasthenozoospermic males in ICSI cycles: a time-lapse sibling oocytes study

“…As stated in a recent study, poor DNA integrity in sperm can cause delayed embryo development, which may be related to the extended time required for oocytes to repair paternal genetic material ( 33 ). Furthermore, from a more microscopic perspective of molecular biology, after the maternal genome controls are transformed during the 8-16 cell stage of human embryos, transcriptional activation of the paternal genome begins to participate in regulating the process of embryonic development ( 35 , 36 ). This may also be one of the reasons why the late embryo and blastocyst development time point in the second ejaculation group was earlier in this study.…”

Longitudinal profiling of human androgenotes through single-cell analysis unveils paternal gene expression dynamics in early embryo development

“…The interplay of maternal and paternal genomes during the first mitotic divisions obscures the analysis of each progenitor’s contributions. Artificially generated uniparental human bioconstructs, also known as parthenogenotes (PG) and androgenotes (AG), have emerged as experimental models with identical genomes to the original oocyte or sperm, respectively, used to create them ( Liao et al , 2020 ). Despite the similar strategies used to generate these bioconstructs in animals and humans ( Xu et al , 2021 ), our previous experience with these uniparental models highlighted shorter cell division cycles in AG compared to PG and biparental human embryos ( Escribá et al , 2016 ).…”