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Review
. 2023 Jan 28;22(1):e12505.
doi: 10.1002/rmb2.12505. eCollection 2023 Jan-Dec.

Reorganization, specialization, and degradation of oocyte maternal components for early development

Yuhkoh Satouh  1 , Ken Sato  1
Affiliations
Review

Reorganization, specialization, and degradation of oocyte maternal components for early development

Yuhkoh Satouh et al. Reprod Med Biol. .

Abstract

Background: Oocyte components are maternally provided, solely determine oocyte quality, and coordinately determine embryo quality with zygotic gene expression. During oocyte maturation, maternal organelles are drastically reorganized and specialized to support oocyte characteristics. A large number of maternal components are actively degraded after fertilization and gradually replaced by zygotic gene products. The molecular basis and the significance of these processes on oocyte/embryo quality are not fully understood.

Methods: Firstly, recent findings in organelle characteristics of other cells or oocytes from model organisms are introduced for further understanding of oocyte organelle reorganization/specialization. Secondly, recent progress in studies on maternal components degradation and their molecular mechanisms are introduced. Finally, future applications of these advancements for predicting mammalian oocyte/embryo quality are discussed.

Main findings: The significance of cellular surface protein degradation via endocytosis for embryonic development, and involvement of biogenesis of lipid droplets in embryonic quality, were recently reported using mammalian model organisms.

Conclusion: Identifying key oocyte component characteristics and understanding their dynamics may lead to new applications in oocyte/embryo quality prediction and improvement. To implement these multidimensional concepts, development of new technical approaches that allow us to address the complexity and efficient studies using model organisms are required.

Keywords: autophagy; endocytosis; oocyte organelles; oocyte quality; ubiquitin‐proteasome system.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

FIGURE 1
FIGURE 1
Changes of oocyte components during oocyte maturation and embryogenesis. In vivo and in vitro mammalian oocyte growth/maturation and embryonic development depicting corresponding stages of follicular development, oocyte maturation, and embryonic development. The changes of oocyte components prior to MZT are described, and the processes discussed in this review is shown in red letters. During the reorganization and specialization, oocyte components changes its localization and characteristics drastically (indicated by color gradation), and large amounts of oocyte components are actively degraded prior to ZGA. GV, germinal vesicle; GVBD, germinal vesicle breakdown; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilization; IVG, in vitro growth; IVM, in vitro maturation; MII, oocyte stops in metaphase of the second meiosis; MZT, maternal‐zygotic transition; PN, pronuclear; ZGA, zygotic gene activation
FIGURE 2
FIGURE 2
Changes in maternal organelles during oocyte maturation. The dispersed ER network is indicated as a meshed pattern. Arrowheads indicate three peaks (bursts) of mitochondrial ATP production (increase of mitochondrial ATP concentration) during in vitro maturation of mouse oocytes. CG, cortical granule; ER, endoplasmic reticulum; GA, Golgi apparatus
FIGURE 3
FIGURE 3
Oocyte proteolytic systems in early embryogenesis. Relative activities of proteolytic systems at each developmental stage are indicated. These stages are mainly studied in mice. Inhibition outcomes are results from gene deletion, gene suppression, or inhibitor assays. Endocytic activity after the 4‐cell stage was not assayed (partly shown with dotted line). Inhibition results using Pitstop2 are indicated. UPS, ubiquitin‐proteasome system
See this image and copyright information in PMC

References

    1. Secomandi L, Borghesan M, Velarde M, Demaria M. The role of cellular senescence in female reproductive aging and the potential for senotherapeutic interventions. Hum Reprod Update. 2022;28(2):172–89. - PMC - PubMed
    1. Vazquez‐Diez C, FitzHarris G. Causes and consequences of chromosome segregation error in preimplantation embryos. Reproduction. 2018;155(1):R63–76. - PubMed
    1. Hoffmann EK, Lambert IH, Pedersen SF. Physiology of cell volume regulation in vertebrates. Physiol Rev. 2009;89(1):193–277. - PubMed
    1. Tscherner AK, Macaulay AD, Ortman CS, Baltz JM. Initiation of cell volume regulation and unique cell volume regulatory mechanisms in mammalian oocytes and embryos. J Cell Physiol. 2021;236(10):7117–33. - PubMed
    1. Yaniz JL, Soler C, Santolaria P. Computer assisted sperm morphometry in mammals: a review. Anim Reprod Sci. 2015;156:1–12. - PubMed

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