Enucleolation and nucleolus transfer in mammalian oocytes and zygotes

Benc, Michal; Fulka, Josef; Strejcek, Frantisek; Morovic, Martin; Murín, Matej; Martinkova, Stanislava; Jettmarová, Dominika; Laurinčík, Jozef

doi:10.1387/ijdb.190002mb

Cited by 8 publications

(8 citation statements)

References 16 publications

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“…In addition, the nucleolus can elevate reaction rates by concentrating rRNA processing factors [ 32 ]. More importantly, dissecting the functions of NPBs in zygotes or early embryos has involved a series of micromanipulations targeting the NPBs, and recent papers have already given thorough descriptions for this [ 7 , 34 ]; it is the liquid-like biophysical properties of NPBs that makes the nucleolus amenable to various micromanipulation procedures. For instance, NLBs isolated from fully grown mouse oocytes can come into close contact with each other and then fuse [ 35 ].…”

Section: Liquid Droplet-like Properties Of Nucleolusmentioning

confidence: 99%

“…For instance, NLBs isolated from fully grown mouse oocytes can come into close contact with each other and then fuse [ 35 ]. Moreover, NLBs in germinal vesicles (GVs) or NPBs in pronuclei can penetrate the nuclear envelope [ 34 ], which also exhibits liquid droplet-like properties. We should bear in mind that causing no irreparable damage to chromosomes is the first prerequisite for nucleolar transplantation approaches.…”

Section: Liquid Droplet-like Properties Of Nucleolusmentioning

confidence: 99%

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Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization

Fu,

Ma,

Liu

2024

Open Biol.

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The nucleolus is the most prominent liquid droplet-like membrane-less organelle in mammalian cells. Unlike the nucleolus in terminally differentiated somatic cells, those in totipotent cells, such as murine zygotes or two-cell embryos, have a unique nucleolar structure known as nucleolus precursor bodies (NPBs). Previously, it was widely accepted that NPBs in zygotes are simply passive repositories of materials that will be gradually used to construct a fully functional nucleolus after zygotic genome activation (ZGA). However, recent research studies have challenged this simplistic view and demonstrated that functions of the NPBs go beyond ribosome biogenesis. In this review, we provide a snapshot of the functions of NPBs in zygotes and early two-cell embryos in mice. We propose that these membrane-less organelles function as a regulatory hub for chromatin organization. On the one hand, NPBs provide the structural platform for centric and pericentric chromatin remodelling. On the other hand, the dynamic changes in nucleolar structure control the release of the pioneer factors (i.e. double homeobox (Dux)). It appears that during transition from totipotency to pluripotency, decline of totipotency and initiation of fully functional nucleolus formation are not independent events but are interconnected. Consequently, it is reasonable to hypothesize that dissecting more unknown functions of NPBs may shed more light on the enigmas of early embryonic development and may ultimately provide novel approaches to improve reprogramming efficiency.

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Section: Liquid Droplet-like Properties Of Nucleolusmentioning

confidence: 99%

Section: Liquid Droplet-like Properties Of Nucleolusmentioning

confidence: 99%

Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization

Fu,

Ma,

Liu

2024

Open Biol.

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“…A powerful tool in studies of heterochromatin structure in mammalian oocytes and zygotes is the so-called “enucleolation”—microsurgical removing of NLBs from mouse GV oocytes and NPBs from the pronuclei (PNs) of zygotes followed by NLB/NPB transfer [ 11 ]. With the help of this micromanipulation technique it was possible to establish that NLBs/NPBs are indispensable for the regulation of MaSat and minor satellite (MiSat) repeats soon after fertilization and serve as major heterochromatin-organizing structure in oocytes and zygotes in the mouse.…”

Section: Chromatin Morphologymentioning

confidence: 99%

“…We discuss the morphological and molecular features of chromatin changes during mammalian oogenesis and embryogenesis, focusing on the characteristic ring structures of heterochromatin, intimately associated with unique nuclear bodies known as the nucleolus-like bodies (NLBs, in oocytes) or the nucleolus precursor bodies (NPBs, in embryos) that are observed in several species, including mouse and human. Both NLBs and NPBs are sometimes referred to as atypical nucleoli (NCLs) [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

Heterochromatin Morphodynamics in Late Oogenesis and Early Embryogenesis of Mammals

Bogolyubova

Bogolyubov

2020

Cells

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During the period of oocyte growth, chromatin undergoes global rearrangements at both morphological and molecular levels. An intriguing feature of oogenesis in some mammalian species is the formation of a heterochromatin ring-shaped structure, called the karyosphere or surrounded “nucleolus”, which is associated with the periphery of the nucleolus-like bodies (NLBs). Morphologically similar heterochromatin structures also form around the nucleolus-precursor bodies (NPBs) in zygotes and persist for several first cleavage divisions in blastomeres. Despite recent progress in our understanding the regulation of gene silencing/expression during early mammalian development, as well as the molecular mechanisms that underlie chromatin condensation and heterochromatin structure, the biological significance of the karyosphere and its counterparts in early embryos is still elusive. We pay attention to both the changes of heterochromatin morphology and to the molecular mechanisms that can affect the configuration and functional activity of chromatin. We briefly discuss how DNA methylation, post-translational histone modifications, alternative histone variants, and some chromatin-associated non-histone proteins may be involved in the formation of peculiar heterochromatin structures intimately associated with NLBs and NPBs, the unique nuclear bodies of oocytes and early embryos.

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“…Several techniques were adapted to increase the efficiency of creation artificial oocytes and their further embryo developmental competence and the resulting produced offspring (Al Jubran et al, 2023;Al Zeidi et al, 2022a,b). The adapted techniques include the recipient cytoplast (Mohammed et al, 2006a,b, Mohammed et al, 2008, 2010, the technique of enucleation (Mohammed et al, 2019), activation method (Montgomery et al, 2022), nucleolus transfer (Benc et al, 2019). The reconstructed "artificial oocytes" seems to be an interesting model for studying meiotic progression of the introduced nuclei or cells, reproductive disorder treatments or for embryonic/somatic cloning.…”

mentioning

confidence: 99%

Do the Mammalian Artificial Oocytes Repair Reproductive Dysfunctions in Mammalian Species?: A Review

Mohammed,

AlGherair,

Al-Suwaiegh

et al. 2024

IJAR

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Artificial oocytes were used of different mammalian species for repairing reproductive dysfunctions. Artificial oocytes are those created in vitro using enucleated germinal vesicle, metaphase I and metaphase II oocytes followed by embryonic cells, somatic cells, pluripotent stem cells and germ cells nuclear transfer. Artificial oocytes are under development, they have the potential to revolutionize reproduction in mammalian species. The potential applications of artificial oocytes include 1) treatment of infertility as premature ovarian failure, ovarian cancer, or other conditions that damage the ovaries, 2) preservation of fertility, 3) creating cloned and transgenic animals. While artificial oocytes have the potential to revolutionize reproductive medicine, there are still a number of challenges that need to be addressed before they can be effectively and safely used in humans including the adapting efficient and safe enucleation techniques. Furthermore, cellular reprogramming is the biggest obstacle for creating artificial oocytes in addition to activation procedures to ensure that artificial oocytes are genetically and epigenetically normal and producing healthy offspring. Several studies are designed to overcome these challenges and there is significant progresses being made. Offspring are obtained in several animals species whereas developed blastocysts were obtained in humans. This review is developed and implemented to discuss the progress in creation of “artificial oocytes” in addition to the factors affecting the developmental competence of reconstructed oocytes.

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Enucleolation and nucleolus transfer in mammalian oocytes and zygotes

Cited by 8 publications

References 16 publications

Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization

Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization

Heterochromatin Morphodynamics in Late Oogenesis and Early Embryogenesis of Mammals

Do the Mammalian Artificial Oocytes Repair Reproductive Dysfunctions in Mammalian Species?: A Review

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