Removal of remodeling/reprogramming factors from oocytes and the impact on the full-term development of cloned embryos

Konno, Satoshi; Wakayama, Sayaka; Ito, Daiyu; Kazama, Kousuke; Hirose, Naoki; Ooga, Masatoshi; Wakayama, Teruhiko

doi:10.1242/dev.190777

Cited by 9 publications

(6 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As soon as they enter the M-phase, the condensed chromosomes are removed, and a donor-differentiated cell nuclear material (either G2-stage or condensed chromosomes) is transferred into these cytoplasts. The eventual disadvantage is that some reprogramming (or other) factors may be bound to condensed chromosomes, and are thus removed with the metaphase plate [ 73 ].…”

Section: The Gain Of Remodeling Capacity and The Suitability Of Atypi...mentioning

confidence: 99%

Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view

Fulka

Loi

Palazzese

et al. 2022

Journal of Reproduction and Development

View full text Add to dashboard Cite

It is now approximately 25 years since the sheep Dolly, the first cloned mammal where the somatic cell nucleus from an adult donor was used for transfer, was born. So far, somatic cell nucleus transfer, where G1-phase nuclei are transferred into cytoplasts obtained by enucleation of mature metaphase II (MII) oocytes followed by the activation of the reconstructed cells, is the most efficient approach to reprogram/remodel the differentiated nucleus. In general, in an enucleated oocyte (cytoplast), the nuclear envelope (NE, membrane) of an injected somatic cell nucleus breaks down and chromosomes condense. This condensation phase is followed, after subsequent activation, by chromatin decondensation and formation of a pseudo-pronucleus (i) whose morphology should resemble the natural postfertilization pronuclei (PNs). Thus, the volume of the transferred nuclei increases considerably by incorporating the content released from the germinal vesicles (GVs). In parallel, the transferred nucleus genes must be reset and function similarly as the relevant genes in normal embryo reprogramming. This, among others, covers the relevant epigenetic modifications and the appropriate organization of chromatin in pseudo-pronuclei. While reprogramming in SCNT is often discussed, the remodeling of transferred nuclei is much less studied, particularly in the context of the developmental potential of SCNT embryos. It is now evident that correct reprogramming mirrors appropriate remodeling. At the same time, it is widely accepted that the process of rebuilding the nucleus following SCNT is instrumental to the overall success of this procedure. Thus, in our contribution, we will mostly focus on the remodeling of transferred nuclei. In particular, we discuss the oocyte organelles that are essential for the development of SCNT embryos.

show abstract

Section: The Gain Of Remodeling Capacity and The Suitability Of Atypi...mentioning

confidence: 99%

Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view

Fulka

Loi

Palazzese

et al. 2022

Journal of Reproduction and Development

View full text Add to dashboard Cite

show abstract

“…Thus, any available information concerning the epigenetic aspects of transforming cell line-committed somatic cell nuclei to totipotent gamete-type nuclei has to be derived from animal studies. Despite the fact that the first cloned animal, Dolly the sheep, was born more than 20 years ago (Wilmut et al, 1997), and the birth of cloned offspring has been achieved in 20 animal species, the efficiency of cloning still remains low (Matoba and Chang, 2018;Konno et al, 2020). In the mouse, for instance, only about 30% of embryos generated by somatic cell nuclear transfer develop to blastocysts, and only 1-2% of embryos transferred to surrogate mothers can reach term (Loi et al, 2016).…”

Section: Epigenetic Aspectsmentioning

confidence: 99%

“…This complex machinery of oocyte remodelling/reprogramming factors is tuned up to be maximally efficient with sperm nuclei. A number of data show that this tune-up is far from being optimal for somatic cell nuclear reprogramming, some of the factors involved being present in excess and other in shortage (Konno et al, 2020). In addition, it has to be taken into account that most data concerning somatic cell nuclear remodelling/reprogramming have been derived from animal experiments.…”

Section: Epigenetic Aspectsmentioning

confidence: 99%

Human artificial oocytes from patients’ somatic cells: past, present and future

Mendoza¹,

Mendoza-Tesarik²

2021

Reproduction and Fertility

View full text Add to dashboard Cite

The first attempts at generating functional human oocytes by using transfer of patients’ somatic cell nuclei, as DNA source, into donor enucleated oocytes date back to the early 2000s. After initial attempts, that gave rather encouraging results, the technique was abandoned because of adverse results with this technique in the mouse model. Priority was then given to the use of induced pluripotent stem (iPS) cells, based on excellent results in the mouse, where mature oocytes and live healthy offspring were achieved. However, these results could not be reproduced in humans, and oogenesis with human iPS cells did not continue beyond the stage of oogonium. These data suggest that the use of enucleated donor oocytes will be necessary to achieve fertilizable human oocytes with somatic cell-derived DNA. The main problem of all these techniques is that they have to meet with two, sometimes contradictory, requirements: the haploidisation of somatic cell-derived DNA, on the one hand, and the remodelling/reprogramming of DNA of somatic cell origin, so as to be capable of supporting all stages of preimplantation and postimplantation development and to give rise to all cell types of the future organism. Further research is needed to determine the optimal strategy to cope with these two requirements.

show abstract

“…After enucleation, the ooplasm was washed and cultured in CZB until micro-insemination. In some experiments, the aspirated nuclei were injected into enucleated ooplasms or un-enucleated MII oocytes in CB containing HEPES-buffered CZB (Konno et al, 2020).…”

Section: Enucleation and Injection Of The Nuclei Of Oocytesmentioning

confidence: 99%

Parental Conflicting Role Mediates Regulation of The Chromatin Structure in The Mouse Zygote

Ooga¹,

Inoue²,

Wakayama³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Parental pronuclei (PN) are asymmetrical in several points but the underlying mechanism for this is still unclear. Recently, a theory has been become broadly accepted that sperm are more than mere vehicles to carry the paternal haploid genome into oocytes. Here, in order to reveal the formation mechanisms for parental asymmetrically relaxed chromatin structure in zygotes, we investigated histone mobility in parthenogenetic-, androgenic-, ROSI-, ELSI-, tICSI-, and ICSI-zygotes with several numbers of PNs with the use of zygotic fluorescence recovery after photobleaching, a method previous established by our group. The results showed that sperm played a role to cause chromatin compaction in both parental PNs. Interestingly, during spermiogenesis, male germ cells acquired this ability and its resistance. On the other hand, oocytes harbored chromatin relaxation ability. Furthermore, the chromatin relaxation factor was competed for between PNs. Thus, these results indicated that the parental asymmetrically relaxed chromatin structure was established as a result of a competition between the PNs for the chromatin relaxation factor that opposed the chromatin compaction effect by sperm. Together, it was suggested that parental germ cells cooperated for their just arisen newborn zygotes by playing a distinct role in the regulation of chromatin structure.

show abstract

Removal of remodeling/reprogramming factors from oocytes and the impact on the full-term development of cloned embryos

Cited by 9 publications

References 41 publications

Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view

Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view

Human artificial oocytes from patients’ somatic cells: past, present and future

Parental Conflicting Role Mediates Regulation of The Chromatin Structure in The Mouse Zygote

Contact Info

Product

Resources

About