1
|
Fu B, Ma H, Liu D. Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization. Open Biol 2024; 14:230358. [PMID: 38689555 PMCID: PMC11065130 DOI: 10.1098/rsob.230358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/26/2023] [Accepted: 03/15/2024] [Indexed: 05/02/2024] Open
Abstract
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.
Collapse
Affiliation(s)
- Bo Fu
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
| | - Hong Ma
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
| | - Di Liu
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
| |
Collapse
|
2
|
FULKA H, LOI P, PALAZZESE L, BENC M, FULKA, Jr. J. Nucleus reprogramming/remodeling through selective enucleation (SE) of immature oocytes and zygotes: a nucleolus point of view. J Reprod Dev 2022; 68:165-172. [PMID: 35431279 PMCID: PMC9184824 DOI: 10.1262/jrd.2022-004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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.
Collapse
Affiliation(s)
- Helena FULKA
- Institute of Experimental Medicine, Prague, Czech Republic
| | - Pasqualino LOI
- Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - Luca PALAZZESE
- Institute of Genetics and Animal Biotechnology of the Polish Academy of Sciences, 05-552 Jastrzebiec, Poland
| | - Michal BENC
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Slovak Republic
| | | |
Collapse
|
3
|
Benc M, Strejcek F, Morovic M, Bartkova A, Murin M, Gad A, Bonnet-Garnier A, Percinic FP, Laurincik J. Improving the Quality of Oocytes with the Help of Nucleolotransfer Therapy. Pharmaceuticals (Basel) 2021; 14:ph14040328. [PMID: 33918523 PMCID: PMC8066131 DOI: 10.3390/ph14040328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 11/16/2022] Open
Abstract
The nucleolus is an important nucleus sub-organelle found in almost all eukaryotic cells. On the one hand, it is known as a differentiated active site of ribosome biogenesis in somatic cells, but on the other hand, in fully grown oocytes, zygotes, and early embryos (up to the major embryonic genome activation), it is in the form of a particular homogenous and compact structure called a fibrillar sphere. Nowadays, thanks to recent studies, we know many important functions of this, no doubt, interesting membraneless nucleus sub-organelle involved in oocyte maturation, embryonic genome activation, rRNA synthesis, etc. However, many questions are still unexplained and remain a mystery. Our aim is to create a comprehensive overview of the recent knowledge on the fibrillar sphere and envision how this knowledge could be utilized in further research in the field of biotechnology and nucleolotransfer therapy.
Collapse
Affiliation(s)
- Michal Benc
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nabrezie mladeze 91, 94974 Nitra, Slovakia; (M.B.); (M.M.); (A.B.); (J.L.)
| | - Frantisek Strejcek
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nabrezie mladeze 91, 94974 Nitra, Slovakia; (M.B.); (M.M.); (A.B.); (J.L.)
- Correspondence: ; Tel.: +421-037-6408-584
| | - Martin Morovic
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nabrezie mladeze 91, 94974 Nitra, Slovakia; (M.B.); (M.M.); (A.B.); (J.L.)
| | - Alexandra Bartkova
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nabrezie mladeze 91, 94974 Nitra, Slovakia; (M.B.); (M.M.); (A.B.); (J.L.)
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, 27721 Libechov, Czech Republic; (M.M.); (A.G.)
| | - Matej Murin
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, 27721 Libechov, Czech Republic; (M.M.); (A.G.)
| | - Ahmed Gad
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, 27721 Libechov, Czech Republic; (M.M.); (A.G.)
| | - Amelie Bonnet-Garnier
- Université Paris-Saclay, UVSQ, INRAE, BREED, 78350 Jouy-en-Josas, France;
- Ecole Nationale Vétérinaire d’Alfort, BREED, 94700 Maisons-Alfort, France
| | - Florina Popovska Percinic
- Faculty of Veterinary Medicine, St. Cyril and Methodius University in Skopje, 1000 Skopje, North Macedonia;
| | - Jozef Laurincik
- Faculty of Natural Sciences, Constantine the Philosopher University in Nitra, Nabrezie mladeze 91, 94974 Nitra, Slovakia; (M.B.); (M.M.); (A.B.); (J.L.)
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, 27721 Libechov, Czech Republic; (M.M.); (A.G.)
| |
Collapse
|