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Pezic D, Weeks S, Varsally W, Dewari PS, Pollard S, Branco MR, Hadjur S. The N-terminus of Stag1 is required to repress the 2C program by maintaining rRNA expression and nucleolar integrity. Stem Cell Reports 2023; 18:2154-2173. [PMID: 37802073 PMCID: PMC10679541 DOI: 10.1016/j.stemcr.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023] Open
Abstract
Our understanding of how STAG proteins contribute to cell identity and disease have largely been studied from the perspective of chromosome topology and protein-coding gene expression. Here, we show that STAG1 is the dominant paralog in mouse embryonic stem cells (mESCs) and is required for pluripotency. mESCs express a wide diversity of naturally occurring Stag1 isoforms, resulting in complex regulation of both the levels of STAG paralogs and the proportion of their unique terminal ends. Skewing the balance of these isoforms impacts cell identity. We define a novel role for STAG1, in particular its N-terminus, in regulating repeat expression, nucleolar integrity, and repression of the two-cell (2C) state to maintain mESC identity. Our results move beyond protein-coding gene regulation via chromatin loops to new roles for STAG1 in nucleolar structure and function, and offer fresh perspectives on how STAG proteins, known to be cancer targets, contribute to cell identity and disease.
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Affiliation(s)
- Dubravka Pezic
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Samuel Weeks
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Wazeer Varsally
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Pooran S Dewari
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Steven Pollard
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, UK
| | - Suzana Hadjur
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK.
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2
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Abstract
The p-arms of the five human acrocentric chromosomes bear nucleolar organizer regions (NORs) comprising ribosomal gene (rDNA) repeats that are organized in a homogeneous tandem array and transcribed in a telomere-to-centromere direction. Precursor ribosomal RNA transcripts are processed and assembled into ribosomal subunits, the nucleolus being the physical manifestation of this process. I review current understanding of nucleolar chromosome biology and describe current exploration into a role for the NOR chromosomal context. Full DNA sequences for acrocentric p-arms are now emerging, aided by the current revolution in long-read sequencing and genome assembly. Acrocentric p-arms vary from 10.1 to 16.7 Mb, accounting for ∼2.2% of the genome. Bordering rDNA arrays, distal junctions, and proximal junctions are shared among the p-arms, with distal junctions showing evidence of functionality. The remaining p-arm sequences comprise multiple satellite DNA classes and segmental duplications that facilitate recombination between heterologous chromosomes, which is likely also involved in Robertsonian translocations.
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Affiliation(s)
- Brian McStay
- Centre for Chromosome Biology, College of Science and Engineering, University of Galway, Galway, Ireland;
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3
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Talbot DE, Vormezeele BJ, Kimble GC, Wineland DM, Kelpsch DJ, Giedt MS, Tootle TL. Prostaglandins limit nuclear actin to control nucleolar function during oogenesis. Front Cell Dev Biol 2023; 11:1072456. [PMID: 36875757 PMCID: PMC9981675 DOI: 10.3389/fcell.2023.1072456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 02/06/2023] [Indexed: 02/19/2023] Open
Abstract
Prostaglandins (PGs), locally acting lipid signals, regulate female reproduction, including oocyte development. However, the cellular mechanisms of PG action remain largely unknown. One cellular target of PG signaling is the nucleolus. Indeed, across organisms, loss of PGs results in misshapen nucleoli, and changes in nucleolar morphology are indicative of altered nucleolar function. A key role of the nucleolus is to transcribe ribosomal RNA (rRNA) to drive ribosomal biogenesis. Here we take advantage of the robust, in vivo system of Drosophila oogenesis to define the roles and downstream mechanisms whereby PGs regulate the nucleolus. We find that the altered nucleolar morphology due to PG loss is not due to reduced rRNA transcription. Instead, loss of PGs results in increased rRNA transcription and overall protein translation. PGs modulate these nucleolar functions by tightly regulating nuclear actin, which is enriched in the nucleolus. Specifically, we find that loss of PGs results in both increased nucleolar actin and changes in its form. Increasing nuclear actin, by either genetic loss of PG signaling or overexpression of nuclear targeted actin (NLS-actin), results in a round nucleolar morphology. Further, loss of PGs, overexpression of NLS-actin or loss of Exportin 6, all manipulations that increase nuclear actin levels, results in increased RNAPI-dependent transcription. Together these data reveal PGs carefully balance the level and forms of nuclear actin to control the level of nucleolar activity required for producing fertilization competent oocytes.
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Affiliation(s)
| | | | | | | | | | | | - Tina L. Tootle
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA, United States
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4
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Inoue T, Taguchi S, Uemura M, Tsujimoto Y, Kokunai K, Ikawa K, Yamashita Y. The migration speed of nucleolar precursor bodies in pronuclei affects in vitro fertilization-derived human embryo ploidy status and live birth. Reprod Med Biol 2023; 22:e12497. [PMID: 36699958 PMCID: PMC9853468 DOI: 10.1002/rmb2.12497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 12/04/2022] [Accepted: 12/21/2022] [Indexed: 01/22/2023] Open
Abstract
Purpose To study the relationship between clinical outcomes after assisted reproduction and the migration speed of nucleolus precursor bodies (NPBs) in male and female pronuclei (mPN; fPN). Methods NPB migration speed, embryo ploidy status, and live birth (LB) were retrospectively analyzed in IVF-derived zygotes. The central coordinates of the mPN, fPN, and NPBs were noted at multiple timepoints. The migration distance of NPBs between two sequential images was measured to calculate NPB migration speed. Results The NPB migration speeds in mPN and fPN were significantly faster in euploid zygotes than in aneuploid zygotes. In multivariate logistic analysis, NPB migration speed in mPN and the female age were associated with euploidy. The NPB migration speeds in mPN and fPN were also significantly faster in zygotes that led to LB than in zygotes that led to no pregnancy. In a receiver operating characteristic curve analysis of LB by NPB migration speed in mPN, the cut-off value was 3.74 μm/h (AUC: 0.825, 95%CI: 0.688-0.963). When the zygotes were categorized by this cut-off value, there were significantly more LBs in zygotes with migration speed ≥ the cut-off (78.9% vs. 21.1%). Conclusions Zygotes with quickly migrating NPBs demonstrated the developmental potential to become a baby.
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Affiliation(s)
- Taketo Inoue
- Umeda Fertility ClinicOsakaJapan,Department of Emergency, Disaster and Critical Care MedicineHyogo Medical UniversityNishinomiyaJapan
| | | | - Mikiko Uemura
- Department of Rehabilitation, Faculty of Health ScienceKansai University of Welfare SciencesOsakaJapan
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5
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Udagawa O, Kato-Udagawa A, Hirano S. Promyelocytic leukemia nuclear body-like structures can assemble in mouse oocytes. Biol Open 2022; 11:275379. [PMID: 35579421 PMCID: PMC9194678 DOI: 10.1242/bio.059130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/06/2022] [Indexed: 11/29/2022] Open
Abstract
Promyelocytic leukemia (PML) nuclear bodies (PML-NBs), a class of membrane-less cellular organelles, participate in various biological activities. PML-NBs are known as the core-shell-type nuclear body, harboring ‘client’ proteins in their core. Although multiple membrane-less organelles work in the oocyte nucleus, PML-NBs have been predicted to be absent from oocytes. Here, we show that some well-known PML clients (but not endogenous PML) co-localized with small ubiquitin-related modifier (SUMO) protein in the nucleolus and peri-centromeric heterochromatin of maturing oocytes. In oocytes devoid of PML-NBs, endogenous PML protein localized in the vicinity of chromatin. During and after meiotic resumption, PML co-localized with SUMO gathering around chromosomes. To examine the benefit of the PML-NB-free intranuclear milieu in oocytes, we deliberately assembled PML-NBs by microinjecting human PML-encoding plasmids into oocytes. Under conditions of limited SUMO availability, assembled PML-NBs tended to cluster. Upon proteotoxic stress, SUMO delocalized from peri-centromeric heterochromatin and co-localized with SC35 (a marker of nuclear speckles)-positive large compartments, which was disturbed by pre-assembled PML-NBs. These observations suggest that the PML-NB-free intranuclear environment helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics. Summary: PML-NB-free intranuclear environment in the oocyte helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics.
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Affiliation(s)
- Osamu Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Ayaka Kato-Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Seishiro Hirano
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
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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.
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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
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Su G, Wang L, Gao G, Wu S, Yang L, Wu M, Liu X, Yang M, Wei Z, Bai C, Li G. C23 gene regulates the nucleolin structure and biosynthesis of ribosomes in bovine intraspecific and interspecific somatic cell nuclear transfer embryos. FASEB J 2021; 35:e21993. [PMID: 34670005 DOI: 10.1096/fj.202100737rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/15/2021] [Accepted: 10/01/2021] [Indexed: 01/07/2023]
Abstract
Somatic cell nuclear transfer (SCNT) can reprogram differentiated somatic cells to produce individual animals, thus having advantages in animal breeding and chromatin reprogramming. Interspecies SCNT (iSCNT) provides extreme cases of reprogramming failure that can be used to understand the basic biological mechanism of genome reprogramming. It is important to understand the possible mechanisms for the failure of zygotic genome activation (ZGA) in iSCNT embryos in order to improve the efficiency of SCNT embryos. In the present study, we compared the development of bovine-bovine (B-B), ovine-ovine (O-O) SCNT, and ovine-bovine (O-B) iSCNT embryos and found that a developmental block existed in the 8-cell stage in O-B iSCNT embryos. RNA sequencing and q-PCR analysis revealed that the large ribosomal subunit genes (RPL) or the small ribosomal subunit genes (RPS) were expressed at lower levels in the O-B iSCNT embryos. The nucleolin (C23) gene that regulates the ribosomal subunit generation was transcribed at a lower level during embryonic development in O-B iSCNT embryos. In addition, the nucleolin exhibited a clear circular-ring structure in B-B 8-cell stage embryos, whereas this was shell-like or dot-like in the O-B embryos. Furthermore, overexpression of C23 could increase the blastocyst rate of both SCNT and iSCNT embryos and partly rectify the ring-like nucleolin structure and the expression of ribosomal subunit related genes were upregulation, while knockdown of C23 increased the shell-like nucleolin-structure in B-B cloned embryos and downregulated the expression of ribosomal subunit related genes. These results implied that abnormal C23 and ribosome subunit gene expression would lead to the developmental block of iSCNT embryos and ZGA failure. Overexpression of the C23 gene could partly improve the blastocyst development and facilitate the nucleolin structure in bovine preimplantation SCNT embryos.
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Affiliation(s)
- Guanghua Su
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Lina Wang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Guangqi Gao
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China
| | - Shanshan Wu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Lei Yang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Meiling Wu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Xuefei Liu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Miaomiao Yang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Zhuying Wei
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Chunling Bai
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Guangpeng Li
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock (R2BGL), Inner Mongolia University, Hohhot, China
- College of Life Sciences, Inner Mongolia University, Hohhot, China
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Migration speed of nucleolus precursor bodies in human male pronuclei: a novel parameter for predicting live birth. J Assist Reprod Genet 2021; 38:1725-1736. [PMID: 33811586 DOI: 10.1007/s10815-021-02172-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/22/2021] [Indexed: 12/26/2022] Open
Abstract
PURPOSE To study the relationship between the migration speed of nucleolus precursor bodies (NPBs) in male and female pronuclei (mPN; fPN) and human embryo development during assisted reproduction. METHODS The migration speed of 263 NPBs from 47 zygotes was quantitated, and embryonic development was observed until the blastocyst stage. The central coordinates of mPN, fPN, and NPBs were noted at multiple timepoints. Then, the distance traveled by the NPBs between two sequential images was measured, and migration speed was calculated. Additionally, we investigated the relationship between NPB migration speed and ploidy status (N = 33) or live birth/ongoing pregnancy (LB/OP) (N = 60) after assisted reproduction. RESULTS The NPB migration speed in both mPN and fPN was significantly faster in the zygotes that developed into blastocysts (N = 25) than that in the zygotes that arrested (N = 22). The timing of blastulation was negatively correlated with NPB migration speed in the mPN. Faster NPB migration was significantly correlated with LB/OP. In multivariate logistic analysis, NPB migration speed in the mPN was the only morphokinetic parameter associated with LB/OP. In a receiver-operating characteristic curve analysis of LB/OP by the NPB migration speed in the mPN, the cut-off value was 4.56 μm/h. When this cut-off value was applied to blastocysts with preimplantation genetic testing for aneuploidy, 100% of the blastocysts faster than or equal to the cut-off value were euploid. CONCLUSION The NPBs migrated faster in zygotes having the potential to develop into a blastocyst, and eventually into a baby. This predictor could be an attractive marker for non-invasive embryo selection.
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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.
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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.)
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