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Skinner MW, Simington CJ, López-Jiménez P, Baran KA, Xu J, Dayani Y, Pryzhkova MV, Page J, Gómez R, Holland AJ, Jordan PW. Spermatocytes have the capacity to segregate chromosomes despite centriole duplication failure. EMBO Rep 2024:10.1038/s44319-024-00187-6. [PMID: 38943004 DOI: 10.1038/s44319-024-00187-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 06/13/2024] [Accepted: 06/14/2024] [Indexed: 06/30/2024] Open
Abstract
Centrosomes are the canonical microtubule organizing centers (MTOCs) of most mammalian cells, including spermatocytes. Centrosomes comprise a centriole pair within a structurally ordered and dynamic pericentriolar matrix (PCM). Unlike in mitosis, where centrioles duplicate once per cycle, centrioles undergo two rounds of duplication during spermatogenesis. The first duplication is during early meiotic prophase I, and the second is during interkinesis. Using mouse mutants and chemical inhibition, we have blocked centriole duplication during spermatogenesis and determined that non-centrosomal MTOCs (ncMTOCs) can mediate chromosome segregation. This mechanism is different from the acentriolar MTOCs that form bipolar spindles in oocytes, which require PCM components, including gamma-tubulin and CEP192. From an in-depth analysis, we identified six microtubule-associated proteins, TPX2, KIF11, NuMA, and CAMSAP1-3, that localized to the non-centrosomal MTOC. These factors contribute to a mechanism that ensures bipolar MTOC formation and chromosome segregation during spermatogenesis when centriole duplication fails. However, despite the successful completion of meiosis and round spermatid formation, centriole inheritance and PLK4 function are required for normal spermiogenesis and flagella assembly, which are critical to ensure fertility.
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Affiliation(s)
- Marnie W Skinner
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Carter J Simington
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Pablo López-Jiménez
- Department of Biology, Autonomous University of Madrid, Madrid, Spain
- MRC Laboratory of Medical Sciences, London, W12 0NN, UK
| | - Kerstin A Baran
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Jingwen Xu
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Yaron Dayani
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Marina V Pryzhkova
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
| | - Jesús Page
- Department of Biology, Autonomous University of Madrid, Madrid, Spain
| | - Rocío Gómez
- Department of Biology, Autonomous University of Madrid, Madrid, Spain
| | - Andrew J Holland
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Philip W Jordan
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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2
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Sahota JS, Thakur RS, Guleria K, Sambyal V. RAD51 and Infertility: A Review and Case-Control Study. Biochem Genet 2024; 62:1216-1230. [PMID: 37563467 DOI: 10.1007/s10528-023-10469-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 07/24/2023] [Indexed: 08/12/2023]
Abstract
RAD51 is a highly conserved recombinase involved in the strand invasion/exchange of double-stranded DNA by homologous single-stranded DNA during homologous recombination repair. Although a majority of existing literature associates RAD51 with the pathogenesis of various types of cancer, recent reports indicate a role of RAD51 in maintenance of fertility. The present study reviews the role of RAD51 and its interacting proteins in spermatogenesis/oogenesis and additionally reports the findings from the molecular genetic screening of RAD51 135 G > C polymorphism in infertile cases and controls. Fifty-nine articles from PubMed and Google Scholar related to the reproductive role of RAD51 were reviewed. For case-control study, the PCR-RFLP method was used to screen the RAD51 135 G > C polymorphism in 201 infertile cases (100 males, 101 females) and 201 age- and gender-matched healthy controls (100 males, 101 females) from Punjab, North-West India. The review of literature shows that RAD51 is indispensable for spermatogenesis and oogenesis in animal models. Reports on the role of RAD51 in human fertility are limited, however it is involved in the pathogenesis of infertility in both males and females. Molecular genetic analyses in the infertile cases and healthy controls showed no statistically significant difference in the genotypic and allelic frequencies for RAD51 135 G > C polymorphism, even after segregation of the cases by type of infertility (primary/secondary). Therefore, the present study concluded that the RAD51 135 G > C polymorphism was neither associated with male nor female infertility in North-West Indians. This is the first report on RAD51 135 G > C polymorphism and infertility.
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Affiliation(s)
- Jatinder Singh Sahota
- Cytogenetics Laboratory, Department of Human Genetics, Guru Nanak Dev University (GNDU), Amritsar, 143005, Punjab, India
| | - Ranveer Singh Thakur
- Cytogenetics Laboratory, Department of Human Genetics, Guru Nanak Dev University (GNDU), Amritsar, 143005, Punjab, India
| | - Kamlesh Guleria
- Cytogenetics Laboratory, Department of Human Genetics, Guru Nanak Dev University (GNDU), Amritsar, 143005, Punjab, India
| | - Vasudha Sambyal
- Cytogenetics Laboratory, Department of Human Genetics, Guru Nanak Dev University (GNDU), Amritsar, 143005, Punjab, India.
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3
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Simerly C, Robertson E, Harrison C, Ward S, George C, Deleon J, Hartnett C, Schatten G. Male meiotic spindle poles are stabilized by TACC3 and cKAP5/chTOG differently from female meiotic or somatic mitotic spindles in mice. Sci Rep 2024; 14:4808. [PMID: 38413710 PMCID: PMC10899211 DOI: 10.1038/s41598-024-55376-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/22/2024] [Indexed: 02/29/2024] Open
Abstract
Transforming acidic acid coiled-coil protein 3 (TACC3) and cytoskeleton associated protein 5 (cKAP5; or colonic hepatic tumor overexpressed gene, chTOG) are vital for spindle assembly and stabilization initiated through TACC3 Aurora-A kinase interaction. Here, TACC3 and cKAP5/chTOG localization with monospecific antibodies is investigated in eGFP-centrin-2- expressing mouse meiotic spermatocytes. Both proteins bind spermatocyte spindle poles but neither kinetochore nor interpolar microtubules, unlike in mitotic mouse fibroblasts or female meiotic oocyte spindles. Spermatocytes do not display a liquid-like spindle domain (LISD), although fusing them into maturing oocytes generates LISD-like TACC3 condensates around sperm chromatin but sparse microtubule assembly. Microtubule inhibitors do not reduce TACC3 and cKAP5/chTOG spindle pole binding. MLN 8237 Aurora-A kinase inhibitor removes TACC3, not cKAP5/chTOG, disrupting spindle organization, chromosome alignment, and impacting spindle pole γ-tubulin intensity. The LISD disruptor 1,6-hexanediol abolished TACC3 in spermatocytes, impacting spindle bipolarity and chromosome organization. Cold microtubule disassembly and rescue experiments in the presence of 1,6-hexanediol reinforce the concept that spermatocyte TACC3 spindle pole presence is not required for spindle pole microtubule assembly. Collectively, meiotic spermatocytes without a LISD localize TACC3 and cKAP5/chTOG exclusively at spindle poles to support meiotic spindle pole stabilization during male meiosis, different from either female meiosis or mitosis.
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Affiliation(s)
- Calvin Simerly
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Emily Robertson
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Caleb Harrison
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Sydney Ward
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Charlize George
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Jasmine Deleon
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Carrie Hartnett
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA
| | - Gerald Schatten
- Departments of Cell Biology, Ob-Gyn-Repro Sci, and Bioengineering, Pittsburgh Development Center of Magee-Womens Research Institute, University of Pittsburgh Medical Center, 204 Craft Avenue, Pittsburgh, PA, 15213, USA.
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4
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Baumann C, Zhang X, Viveiros MM, De La Fuente R. Pericentric major satellite transcription is essential for meiotic chromosome stability and spindle pole organization. Open Biol 2023; 13:230133. [PMID: 37935356 PMCID: PMC10645078 DOI: 10.1098/rsob.230133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 09/28/2023] [Indexed: 11/09/2023] Open
Abstract
In somatic cells, mitotic transcription of major satellite non-coding RNAs is tightly regulated and essential for heterochromatin formation and the maintenance of genome integrity. We recently demonstrated that major satellite transcripts are expressed, and chromatin-bound during mouse oocyte meiosis. Pericentric satellite RNAs are also expressed in human oocytes. However, the specific biological function(s) during oocyte meiosis remain to be established. Here, we use validated locked nucleic acid gapmers for major satellite RNA depletion followed by live cell imaging, and superresolution analysis to determine the role of pericentric non-coding RNAs during female meiosis. Depletion of satellite RNA induces mesoscale changes in pericentric heterochromatin structure leading to chromosome instability, kinetochore attachment errors and abnormal chromosome alignment. Chromosome misalignment is associated with spindle defects, microtubule instability and, unexpectedly, loss of acentriolar microtubule organizing centre (aMTOC) tethering to spindle poles. Pericentrin fragmentation and failure to assemble ring-like aMTOCs with loss of associated polo-like kinase 1 provide critical insight into the mechanisms leading to impaired spindle pole integrity. Inhibition of transcription or RNA splicing phenocopies the chromosome alignment errors and spindle defects, suggesting that pericentric transcription during oocyte meiosis is required to regulate heterochromatin structure, chromosome segregation and maintenance of spindle organization.
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Affiliation(s)
- Claudia Baumann
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-0002, USA
| | - Xiangyu Zhang
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-0002, USA
| | - Maria M Viveiros
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-0002, USA
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA 30602-0002, USA
| | - Rabindranath De La Fuente
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-0002, USA
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA 30602-0002, USA
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5
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Qiao FX, Sun MX, Xu ZR, Liu YC, Chen YZ, Wang HL, Qi ZQ, Xu CL, Liu Y. Chloroacetonitrile exposure induces endoplasmic reticulum stress and affects spindle assembly in mouse oocytes. Food Chem Toxicol 2023; 176:113736. [PMID: 36940772 DOI: 10.1016/j.fct.2023.113736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023]
Abstract
Chloroacetonitrile (CAN) is a halogenated acetonitrile often produced while disinfecting drinking water. Previous studies have shown that maternal exposure to CAN interferes with fetal development; however, the adverse effects on maternal oocytes remain unknown. In this study, in vitro exposure of mouse oocytes to CAN reduced maturation significantly. Transcriptomics analysis showed that CAN altered the expression of multiple oocyte genes, especially those associated with the protein folding process. CAN exposure induced reactive oxygen species production, accompanied by endoplasmic reticulum (ER) stress and increased glucose regulated protein 78, C/EBP homologous protein and activating transcription factor 6 expression. Moreover, our results indicated that spindle morphology was impaired after CAN exposure. CAN disrupted polo-like kinase 1, pericentrin and p-Aurora A distribution, which may be an origin inducer that disrupts spindle assemble. Furthermore, exposure to CAN in vivo impaired follicular development. Taken together, our findings indicate that CAN exposure induces ER stress and affects spindle assembly in mouse oocytes.
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Affiliation(s)
- Feng-Xin Qiao
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China
| | - Ming-Xin Sun
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China
| | - Zhi-Ran Xu
- Translational Medicine Research Center, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, Guangxi, 530011, China
| | - Yue-Cen Liu
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China
| | - Yan-Zhu Chen
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China
| | - Hai-Long Wang
- Department of Basic Medicine, School of Medicine, Xiamen University, Xiamen, Fujian, 361102, China
| | - Zhong-Quan Qi
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China
| | - Chang-Long Xu
- Reproductive Medical Center of Nanning Second People's Hospital, Nanning, Guangxi, 530031, China.
| | - Yu Liu
- Medical College, Guangxi University, Nanning, Guangxi, 530004, China.
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6
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PAK2 is essential for chromosome alignment in metaphase I oocytes. Cell Death Dis 2023; 14:150. [PMID: 36813765 PMCID: PMC9947007 DOI: 10.1038/s41419-023-05585-7] [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: 08/04/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 02/24/2023]
Abstract
As a highly conserved and ubiquitously expressed serine/threonine kinase, p21-activated kinase 2 (PAK2) participates in diverse biologic events. However, its roles in mouse oocyte meiotic maturation remain unclear. The present study revealed that mouse oocytes depleted of Pak2 were unable to completely progress through meiosis and that a majority were arrested at metaphase I. Pak2 depletion thus prompted MI arrest and induced meiotic chromosome alignment defects in mouse oocytes, in part due to a reduction in polo-like kinase (PLK1). We demonstrated that PAK2's interaction with PLK1 protected it from degradation by APC/CCdh1, and that it promoted meiotic progression and bipolar spindle formation. Our data collectively display critical functions for PAK2 in meiotic progression and chromosome alignment in mouse oocytes.
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7
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Gómez R, Viera A, Moreno-Mármol T, Berenguer I, Guajardo-Grence A, Tóth A, Parra MT, Suja JA. Kinase PLK1 regulates the disassembly of the lateral elements and the assembly of the inner centromere during the diakinesis/metaphase I transition in male mouse meiosis. Front Cell Dev Biol 2023; 10:1069946. [PMID: 36733339 PMCID: PMC9887526 DOI: 10.3389/fcell.2022.1069946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/19/2022] [Indexed: 01/15/2023] Open
Abstract
PLK1 is a serine/threonine kinase with crucial roles during mitosis. However, its involvement during mammalian male meiosis remains largely unexplored. By inhibiting the kinase activity of PLK1 using BI 2536 on organotypic cultures of seminiferous tubules, we found that the disassembly of SYCP3 and HORMAD1 from the lateral elements of the synaptonemal complex during diakinesis is impeded. We also found that the normal recruitment of SYCP3 and HORMAD1 to the inner centromere in prometaphase I spermatocytes did not occur. Additionally, we analyzed the participation of PLK1 in the assembly of the inner centromere by studying its implication in the Bub1-H2AT120ph-dependent recruitment of shugoshin SGO2, and the Haspin-H3T3ph-dependent recruitment of Aurora B/C and Borealin. Our results indicated that both pathways are regulated by PLK1. Altogether, our results demonstrate that PLK1 is a master regulator of the late prophase I/metaphase I transition in mouse spermatocytes.
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Affiliation(s)
- Rocío Gómez
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain,*Correspondence: Rocío Gómez, ; José A. Suja,
| | - Alberto Viera
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Tania Moreno-Mármol
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Inés Berenguer
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain,Departamento de Neuropatología Molecular, Centro de Biología Molecular Severo Ochoa, Campus de la Universidad Autónoma de Madrid, Madrid, Spain
| | - Andrea Guajardo-Grence
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain,Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria del Hospital Universitario de La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Attila Tóth
- Institute of Physiological Chemistry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - María Teresa Parra
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - José A. Suja
- Unidad de Biología Celular, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain,*Correspondence: Rocío Gómez, ; José A. Suja,
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8
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Kalous J, Aleshkina D. Multiple Roles of PLK1 in Mitosis and Meiosis. Cells 2023; 12:cells12010187. [PMID: 36611980 PMCID: PMC9818836 DOI: 10.3390/cells12010187] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 01/05/2023] Open
Abstract
Cells are equipped with a diverse network of signaling and regulatory proteins that function as cell cycle regulators and checkpoint proteins to ensure the proper progression of cell division. A key regulator of cell division is polo-like kinase 1 (PLK1), a member of the serine/threonine kinase family that plays an important role in regulating the mitotic and meiotic cell cycle. The phosphorylation of specific substrates mediated by PLK1 controls nuclear envelope breakdown (NEBD), centrosome maturation, proper spindle assembly, chromosome segregation, and cytokinesis. In mammalian oogenesis, PLK1 is essential for resuming meiosis before ovulation and for establishing the meiotic spindle. Among other potential roles, PLK1 regulates the localized translation of spindle-enriched mRNAs by phosphorylating and thereby inhibiting the translational repressor 4E-BP1, a downstream target of the mTOR (mammalian target of rapamycin) pathway. In this review, we summarize the functions of PLK1 in mitosis, meiosis, and cytokinesis and focus on the role of PLK1 in regulating mRNA translation. However, knowledge of the role of PLK1 in the regulation of meiosis remains limited.
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9
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Overexpression of Tfap2a in Mouse Oocytes Impaired Spindle and Chromosome Organization. Int J Mol Sci 2022; 23:ijms232214376. [PMID: 36430853 PMCID: PMC9699359 DOI: 10.3390/ijms232214376] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Transcription factor AP-2-alpha (Tfap2a) is an important sequence-specific DNA-binding protein that can regulate the transcription of multiple genes by collaborating with inducible viral and cellular enhancer elements. In this experiment, the expression, localization, and functions of Tfap2a were investigated in mouse oocytes during maturation. Overexpression via microinjection of Myc-Tfap2a mRNA into the ooplasm, immunofluorescence, and immunoblotting were used to study the role of Tfap2a in mouse oocyte meiosis. According to our results, Tfap2a plays a vital role in mouse oocyte maturation. Levels of Tfap2a in GV oocytes of mice suffering from type 2 diabetes increased considerably. Tfap2a was distributed in both the ooplasm and nucleoplasm, and its level gradually increased as meiosis resumption progressed. The overexpression of Tfap2a loosened the chromatin, accelerated germinal vesicle breakdown (GVBD), and blocked the first polar body extrusion 14 h after maturation in vitro. The width of the metaphase plate at metaphase I stage increased, and the spindle and chromosome organization at metaphase II stage were disrupted in the oocytes by overexpressed Tfap2a. Furthermore, Tfap2a overexpression dramatically boosted the expression of p300 in mouse GV oocytes. Additionally, the levels of pan histone lysine acetylation (Pan Kac), histone H4 lysine 12 acetylation (H4K12ac), and H4 lysine 16 acetylation (H4K16ac), as well as pan histone lysine lactylation (Pan Kla), histone H3 lysine18 lactylation (H3K18la), and H4 lysine12 lactylation (H4K12la), were all increased in GV oocytes after Tfap2a overexpression. Collectively, Tfap2a overexpression upregulated p300, increased the levels of histone acetylation and lactylation, impeded spindle assembly and chromosome alignment, and ultimately hindered mouse oocyte meiosis.
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10
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Mo X, Liu F, Xing C, Shan M, Yao B, Sun Q, Zou Y, Zhang K, Tan J, Sun S, Ren Y. Age‐related SUMOylation of PLK1 is essential to meiosis progression in mouse oocytes. J Cell Physiol 2022; 237:4580-4590. [DOI: 10.1002/jcp.30910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 10/09/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Xiao‐Long Mo
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
| | - Feng Liu
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
| | - Chun‐Hua Xing
- College of Animal Science and Technology Nanjing Agricultural University Nanjing Jiangsu China
| | - Meng‐Meng Shan
- College of Animal Science and Technology Nanjing Agricultural University Nanjing Jiangsu China
| | - Bo Yao
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
| | - Qi‐Qi Sun
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
| | - Yuan‐Jing Zou
- College of Animal Science and Technology Nanjing Agricultural University Nanjing Jiangsu China
| | - Kun‐Huan Zhang
- College of Animal Science and Technology Nanjing Agricultural University Nanjing Jiangsu China
| | - Jun Tan
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
| | - Shao‐Chen Sun
- College of Animal Science and Technology Nanjing Agricultural University Nanjing Jiangsu China
| | - Yan‐Ping Ren
- Department of Histology and Embryology, School of Basic Medicine Zunyi Medical University Zunyi Guizhou China
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11
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Das D, Arur S. Regulation of oocyte maturation: Role of conserved ERK signaling. Mol Reprod Dev 2022; 89:353-374. [PMID: 35908193 PMCID: PMC9492652 DOI: 10.1002/mrd.23637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/12/2022] [Accepted: 07/18/2022] [Indexed: 11/11/2022]
Abstract
During oogenesis, oocytes arrest at meiotic prophase I to acquire competencies for resuming meiosis, fertilization, and early embryonic development. Following this arrested period, oocytes resume meiosis in response to species-specific hormones, a process known as oocyte maturation, that precedes ovulation and fertilization. Involvement of endocrine and autocrine/paracrine factors and signaling events during maintenance of prophase I arrest, and resumption of meiosis is an area of active research. Studies in vertebrate and invertebrate model organisms have delineated the molecular determinants and signaling pathways that regulate oocyte maturation. Cell cycle regulators, such as cyclin-dependent kinase (CDK1), polo-like kinase (PLK1), Wee1/Myt1 kinase, and the phosphatase CDC25 play conserved roles during meiotic resumption. Extracellular signal-regulated kinase (ERK), on the other hand, while activated during oocyte maturation in all species, regulates both species-specific, as well as conserved events among different organisms. In this review, we synthesize the general signaling mechanisms and focus on conserved and distinct functions of ERK signaling pathway during oocyte maturation in mammals, non-mammalian vertebrates, and invertebrates such as Drosophila and Caenorhabditis elegans.
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Affiliation(s)
- Debabrata Das
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Swathi Arur
- Department of Genetics, UT MD Anderson Cancer Center, Houston, TX 77030, USA
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12
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Wellard SR, Skinner MW, Zhao X, Shults C, Jordan PW. PLK1 depletion alters homologous recombination and synaptonemal complex disassembly events during mammalian spermatogenesis. Mol Biol Cell 2022; 33:ar37. [PMID: 35274968 PMCID: PMC9282006 DOI: 10.1091/mbc.e21-03-0115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 02/25/2022] [Accepted: 03/03/2022] [Indexed: 11/11/2022] Open
Abstract
Homologous recombination (HR) is an essential meiotic process that contributes to the genetic variation of offspring and ensures accurate chromosome segregation. Recombination is facilitated by the formation and repair of programmed DNA double-strand breaks. These DNA breaks are repaired via recombination between maternal and paternal homologous chromosomes and a subset result in the formation of crossovers. HR and crossover formation is facilitated by synapsis of homologous chromosomes by a proteinaceous scaffold structure known as the synaptonemal complex (SC). Recent studies in yeast and worms have indicated that polo-like kinases (PLKs) regulate several events during meiosis, including DNA recombination and SC dynamics. Mammals express four active PLKs (PLK1-4), and our previous work assessing localization and kinase function in mouse spermatocytes suggested that PLK1 coordinates nuclear events during meiotic prophase. Therefore, we conditionally mutated Plk1 in early prophase spermatocytes and assessed stages of HR, crossover formation, and SC processes. Plk1 mutation resulted in increased RPA foci and reduced RAD51/DMC1 foci during zygonema, and an increase of both class I and class II crossover events. Furthermore, the disassembly of SC lateral elements was aberrant. Our results highlight the importance of PLK1 in regulating HR and SC disassembly during spermatogenesis.
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Affiliation(s)
- Stephen R. Wellard
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Marnie W. Skinner
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Xueqi Zhao
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Chris Shults
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
| | - Philip W. Jordan
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205
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13
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Dunkley S, Scheffler K, Mogessie B. Cytoskeletal form and function in mammalian oocytes and zygotes. Curr Opin Cell Biol 2022; 75:102073. [PMID: 35364486 DOI: 10.1016/j.ceb.2022.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 11/28/2022]
Abstract
The actin and microtubule cytoskeletons of mammalian oocytes and zygotes exist in distinct forms at various subcellular locations. This enables each cytoskeletal system to perform vastly different functions in time and space within the same cell. In recent years, key discovery enabling tools including light-sensitive microscopy assays have helped to illuminate cytoskeletal form and function in female reproductive cell biology. New findings include unexpected participation of F-actin in oocyte chromosome segregation, oocyte specific modes of spindle self-organization as well as existence of nuclear actin polymers whose functions are only starting to emerge. Functional actin-microtubule interactions have also been identified as an important feature that supports mammalian embryo development. Other advances have revealed reproductive age-related changes in chromosome structure and dynamics that predispose mammalian eggs to aneuploidy.
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Affiliation(s)
- Sam Dunkley
- School of Biochemistry, University of Bristol, BS8 1TD, Bristol, UK
| | | | - Binyam Mogessie
- School of Biochemistry, University of Bristol, BS8 1TD, Bristol, UK; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, 06511, USA.
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14
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Floriot S, Bellutti L, Castille J, Moison P, Messiaen S, Passet B, Boulanger L, Boukadiri A, Tourpin S, Beauvallet C, Vilotte M, Riviere J, Péchoux C, Bertaud M, Vilotte JL, Livera G. CEP250 is Required for Maintaining Centrosome Cohesion in the Germline and Fertility in Male Mice. Front Cell Dev Biol 2022; 9:754054. [PMID: 35127699 PMCID: PMC8809461 DOI: 10.3389/fcell.2021.754054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/24/2021] [Indexed: 12/02/2022] Open
Abstract
Male gametogenesis involves both mitotic divisions to amplify germ cell progenitors that gradually differentiate and meiotic divisions. Centrosomal regulation is essential for both types of divisions, with centrioles remaining tightly paired during the interphase. Here, we generated and characterized the phenotype of mutant mice devoid of Cep250/C-Nap1, a gene encoding for a docking protein for fibers linking centrioles, and characterized their phenotype. The Cep250-/- mice presented with no major defects, apart from male infertility due to a reduction in the spermatogonial pool and the meiotic blockade. Spermatogonial stem cells expressing Zbtb16 were not affected, whereas the differentiating spermatogonia were vastly lost. These cells displayed abnormal γH2AX-staining, accompanied by an increase in the apoptotic rate. The few germ cells that survived at this stage, entered the meiotic prophase I and were arrested at a pachytene-like stage, likely due to synapsis defects and the unrepaired DNA double-strand breaks. In these cells, centrosomes split up precociously, with γ-tubulin foci being separated whereas these were closely associated in wild-type cells. Interestingly, this lack of cohesion was also observed in wild-type female meiocytes, likely explaining the normal fertility of Cep250-/- female mice. Taken together, this study proposes a specific requirement of centrosome cohesion in the male germline, with a crucial role of CEP250 in both differentiating spermatogonia and meiotic spermatocytes.
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Affiliation(s)
- Sandrine Floriot
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Laura Bellutti
- Laboratory of Development of the Gonads, UMRE008 Genetic Stability Stem Cells and Radiations, IRCM/IBFJ CEA, Université de Paris, Université Paris-Saclay, Paris, France
- *Correspondence: Laura Bellutti, ; Gabriel Livera,
| | - Johan Castille
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Pauline Moison
- Laboratory of Development of the Gonads, UMRE008 Genetic Stability Stem Cells and Radiations, IRCM/IBFJ CEA, Université de Paris, Université Paris-Saclay, Paris, France
| | - Sébastien Messiaen
- Laboratory of Development of the Gonads, UMRE008 Genetic Stability Stem Cells and Radiations, IRCM/IBFJ CEA, Université de Paris, Université Paris-Saclay, Paris, France
| | - Bruno Passet
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Laurent Boulanger
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Abdelhak Boukadiri
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Sophie Tourpin
- Laboratory of Development of the Gonads, UMRE008 Genetic Stability Stem Cells and Radiations, IRCM/IBFJ CEA, Université de Paris, Université Paris-Saclay, Paris, France
| | | | - Marthe Vilotte
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Julie Riviere
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Christine Péchoux
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Maud Bertaud
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Jean-Luc Vilotte
- INRAe, AgroParisTech, Université Paris-Saclay, GABI, Jouy-en-Josas, France
| | - Gabriel Livera
- Laboratory of Development of the Gonads, UMRE008 Genetic Stability Stem Cells and Radiations, IRCM/IBFJ CEA, Université de Paris, Université Paris-Saclay, Paris, France
- *Correspondence: Laura Bellutti, ; Gabriel Livera,
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15
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Blengini CS, Schindler K. Acentriolar spindle assembly in mammalian female meiosis and the consequences of its perturbations on human reproduction. Biol Reprod 2021; 106:253-263. [PMID: 34791041 DOI: 10.1093/biolre/ioab210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/26/2021] [Accepted: 11/11/2021] [Indexed: 12/18/2022] Open
Abstract
The purpose of meiosis is to generate developmentally competent, haploid gametes with the correct number of chromosomes. For reasons not completely understood, female meiosis is more prone to chromosome segregation errors than meiosis in males, leading to an abnormal number of chromosomes, or aneuploidy, in gametes. Meiotic spindles are the cellular machinery essential for the proper segregation of chromosomes. One unique feature of spindle structures in female meiosis is spindles poles that lack centrioles. The process of building a meiotic spindle without centrioles is complex and requires precise coordination of different structural components, assembly factors, motor proteins, and signaling molecules at specific times and locations to regulate each step. In this review, we discuss the basics of spindle formation during oocyte meiotic maturation focusing on mouse and human studies. Finally, we review different factors that could alter the process of spindle formation and its stability. We conclude with a discussion of how different assisted reproductive technologies (ART) could affect spindles and the consequences these perturbations may have for subsequent embryo development.
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Affiliation(s)
- Cecilia S Blengini
- Rutgers University, Human Genetics Institute of New Jersey, Piscataway, NJ 08854 USA
| | - Karen Schindler
- Rutgers University, Human Genetics Institute of New Jersey, Piscataway, NJ 08854 USA
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16
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Menon DU, Kirsanov O, Geyer CB, Magnuson T. Mammalian SWI/SNF chromatin remodeler is essential for reductional meiosis in males. Nat Commun 2021; 12:6581. [PMID: 34772938 PMCID: PMC8589837 DOI: 10.1038/s41467-021-26828-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/22/2021] [Indexed: 11/09/2022] Open
Abstract
The mammalian SWI/SNF nucleosome remodeler is essential for spermatogenesis. Here, we identify a role for ARID2, a PBAF (Polybromo - Brg1 Associated Factor)-specific subunit, in meiotic division. Arid2cKO spermatocytes arrest at metaphase-I and are deficient in spindle assembly, kinetochore-associated Polo-like kinase1 (PLK1), and centromeric targeting of Histone H3 threonine3 phosphorylation (H3T3P) and Histone H2A threonine120 phosphorylation (H2AT120P). By determining ARID2 and BRG1 genomic associations, we show that PBAF localizes to centromeres and promoters of genes known to govern spindle assembly and nuclear division in spermatocytes. Consistent with gene ontology of target genes, we also identify a role for ARID2 in centrosome stability. Additionally, misexpression of genes such as Aurkc and Ppp1cc (Pp1γ), known to govern chromosome segregation, potentially compromises the function of the chromosome passenger complex (CPC) and deposition of H3T3P, respectively. Our data support a model where-in PBAF activates genes essential for meiotic cell division.
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Affiliation(s)
- Debashish U Menon
- Department of Genetics, and Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7264, USA
| | - Oleksandr Kirsanov
- Department of Anatomy & Cell Biology at the Brody School of Medicine, East Carolina University, Greenville, NC, 27858, USA
| | - Christopher B Geyer
- Department of Anatomy & Cell Biology at the Brody School of Medicine, East Carolina University, Greenville, NC, 27858, USA
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, 27858, USA
| | - Terry Magnuson
- Department of Genetics, and Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7264, USA.
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17
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Wellard SR, Zhang Y, Shults C, Zhao X, McKay M, Murray SA, Jordan PW. Overlapping roles for PLK1 and Aurora A during meiotic centrosome biogenesis in mouse spermatocytes. EMBO Rep 2021; 22:e51023. [PMID: 33615678 PMCID: PMC8024899 DOI: 10.15252/embr.202051023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/29/2020] [Accepted: 01/21/2021] [Indexed: 01/09/2023] Open
Abstract
The establishment of bipolar spindles during meiotic divisions ensures faithful chromosome segregation to prevent gamete aneuploidy. We analyzed centriole duplication, as well as centrosome maturation and separation during meiosis I and II using mouse spermatocytes. The first round of centriole duplication occurs during early prophase I, and then, centrosomes mature and begin to separate by the end of prophase I to prime formation of bipolar metaphase I spindles. The second round of centriole duplication occurs at late anaphase I, and subsequently, centrosome separation coordinates bipolar segregation of sister chromatids during meiosis II. Using a germ cell-specific conditional knockout strategy, we show that Polo-like kinase 1 and Aurora A kinase are required for centrosome maturation and separation prior to metaphase I, leading to the formation of bipolar metaphase I spindles. Furthermore, we show that PLK1 is required to block the second round of centriole duplication and maturation until anaphase I. Our findings emphasize the importance of maintaining strict spatiotemporal control of cell cycle kinases during meiosis to ensure proficient centrosome biogenesis and, thus, accurate chromosome segregation during spermatogenesis.
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Affiliation(s)
- Stephen R Wellard
- Biochemistry and Molecular Biology DepartmentJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
| | - Yujiao Zhang
- Biochemistry and Molecular Biology DepartmentJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
| | - Chris Shults
- Biochemistry and Molecular Biology DepartmentJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
| | - Xueqi Zhao
- Biochemistry and Molecular Biology DepartmentJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
| | | | | | - Philip W Jordan
- Biochemistry and Molecular Biology DepartmentJohns Hopkins University Bloomberg School of Public HealthBaltimoreMDUSA
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18
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Blengini CS, Ibrahimian P, Vaskovicova M, Drutovic D, Solc P, Schindler K. Aurora kinase A is essential for meiosis in mouse oocytes. PLoS Genet 2021; 17:e1009327. [PMID: 33901174 PMCID: PMC8102010 DOI: 10.1371/journal.pgen.1009327] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 05/06/2021] [Accepted: 04/08/2021] [Indexed: 12/18/2022] Open
Abstract
The Aurora protein kinases are well-established regulators of spindle building and chromosome segregation in mitotic and meiotic cells. In mouse oocytes, there is significant Aurora kinase A (AURKA) compensatory abilities when the other Aurora kinase homologs are deleted. Whether the other homologs, AURKB or AURKC can compensate for loss of AURKA is not known. Using a conditional mouse oocyte knockout model, we demonstrate that this compensation is not reciprocal because female oocyte-specific knockout mice are sterile, and their oocytes fail to complete meiosis I. In determining AURKA-specific functions, we demonstrate that its first meiotic requirement is to activate Polo-like kinase 1 at acentriolar microtubule organizing centers (aMTOCs; meiotic spindle poles). This activation induces fragmentation of the aMTOCs, a step essential for building a bipolar spindle. We also show that AURKA is required for regulating localization of TACC3, another protein required for spindle building. We conclude that AURKA has multiple functions essential to completing MI that are distinct from AURKB and AURKC.
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Affiliation(s)
- Cecilia S. Blengini
- Department of Genetics; Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- Human Genetics Institute of New Jersey; Piscataway, New Jersey, United States of America
| | - Patricia Ibrahimian
- Department of Genetics; Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Michaela Vaskovicova
- Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
| | - David Drutovic
- Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
| | - Petr Solc
- Institute of Animal Physiology and Genetics of the Czech Academy of Sciences, Libechov, Czech Republic
| | - Karen Schindler
- Department of Genetics; Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- Human Genetics Institute of New Jersey; Piscataway, New Jersey, United States of America
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19
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Gómez-Redondo I, Planells B, Cánovas S, Ivanova E, Kelsey G, Gutiérrez-Adán A. Genome-wide DNA methylation dynamics during epigenetic reprogramming in the porcine germline. Clin Epigenetics 2021; 13:27. [PMID: 33536045 PMCID: PMC7860200 DOI: 10.1186/s13148-021-01003-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/04/2021] [Indexed: 01/03/2023] Open
Abstract
Background Prior work in mice has shown that some retrotransposed elements remain substantially methylated during DNA methylation reprogramming of germ cells. In the pig, however, information about this process is scarce. The present study was designed to examine the methylation profiles of porcine germ cells during the time course of epigenetic reprogramming. Results Sows were artificially inseminated, and their fetuses were collected 28, 32, 36, 39, and 42 days later. At each time point, genital ridges were dissected from the mesonephros and germ cells were isolated through magnetic-activated cell sorting using an anti-SSEA-1 antibody, and recovered germ cells were subjected to whole-genome bisulphite sequencing. Methylation levels were quantified using SeqMonk software by performing an unbiased analysis, and persistently methylated regions (PMRs) in each sex were determined to extract those regions showing 50% or more methylation. Most genomic elements underwent a dramatic loss of methylation from day 28 to day 36, when the lowest levels were shown. By day 42, there was evidence for the initiation of genomic re-methylation. We identified a total of 1456 and 1122 PMRs in male and female germ cells, respectively, and large numbers of transposable elements (SINEs, LINEs, and LTRs) were found to be located within these PMRs. Twenty-one percent of the introns located in these PMRs were found to be the first introns of a gene, suggesting their regulatory role in the expression of these genes. Interestingly, most of the identified PMRs were demethylated at the blastocyst stage. Conclusions Our findings indicate that methylation reprogramming in pig germ cells follows the general dynamics shown in mice and human, unveiling genomic elements that behave differently between male and female germ cells.
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Affiliation(s)
| | | | - Sebastián Cánovas
- Physiology of Reproduction Group, Department of Physiology, Universidad de Murcia, Campus Mare Nostrum, Murcia, Spain.,Instituto Murciano de Investigación Biosanitaria, IMIB-Arrixaca-UMU, Murcia, Spain
| | - Elena Ivanova
- Epigenetics Programme, The Babraham Institute, Cambridge, UK
| | - Gavin Kelsey
- Epigenetics Programme, The Babraham Institute, Cambridge, UK.,Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
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