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Milton AM, Marín-Gual L, Lister NC, McIntyre KL, Grady PGS, Laird MK, Bond DM, Hore TA, O'Neill RJ, Pask AJ, Renfree MB, Ruiz-Herrera A, Waters PD. Imprinted X chromosome inactivation in marsupials: The paternal X arrives at the egg with a silent DNA methylation profile. Proc Natl Acad Sci U S A 2024; 121:e2412185121. [PMID: 39190362 PMCID: PMC11388282 DOI: 10.1073/pnas.2412185121] [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: 06/19/2024] [Accepted: 07/22/2024] [Indexed: 08/28/2024] Open
Abstract
X chromosome inactivation (XCI) is an epigenetic process that results in the transcriptional silencing of one X chromosome in the somatic cells of females. This phenomenon is common to both eutherian and marsupial mammals, but there are fundamental differences. In eutherians, the X chosen for silencing is random. DNA methylation on the eutherian inactive X is high at transcription start sites (TSSs) and their flanking regions, resulting in universally high DNA methylation. This contrasts XCI in marsupials where the paternally derived X is always silenced, and in which DNA methylation is low at TSSs and flanking regions. Here, we examined the DNA methylation status of the tammar wallaby X chromosome during spermatogenesis to determine the DNA methylation profile of the paternal X prior to and at fertilization. Whole genome enzymatic methylation sequencing was carried out on enriched flow-sorted populations of premeiotic, meiotic, and postmeiotic cells. We observed that the X displayed a pattern of DNA methylation from spermatogonia to mature sperm that reflected the inactive X in female somatic tissue. Therefore, the paternal X chromosome arrives at the egg with a DNA methylation profile that reflects the transcriptionally silent X in adult female somatic tissue. We present this epigenetic signature as a candidate for the long sought-after imprint for paternal XCI in marsupials.
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Affiliation(s)
- Ashley M Milton
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Laia Marín-Gual
- Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Nicholas C Lister
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Kim L McIntyre
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Patrick G S Grady
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Melanie K Laird
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Donna M Bond
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Timothy A Hore
- Department of Anatomy, University of Otago, Dunedin 9016, New Zealand
| | - Rachel J O'Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Andrew J Pask
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Aurora Ruiz-Herrera
- Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Paul D Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia
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UBR2 of the N-end rule pathway is required for chromosome stability via histone ubiquitylation in spermatocytes and somatic cells. PLoS One 2012; 7:e37414. [PMID: 22616001 PMCID: PMC3355131 DOI: 10.1371/journal.pone.0037414] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Accepted: 04/19/2012] [Indexed: 11/20/2022] Open
Abstract
The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells.
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Gu C, Tong Q, Zheng L, Liang Z, Pu J, Mei H, Hu T, Du Z, Tian F, Zeng F. TSEG-1, a novel member of histone H2A variants, participates in spermatogenesis via promoting apoptosis of spermatogenic cells. Genomics 2010; 95:278-89. [PMID: 20188161 DOI: 10.1016/j.ygeno.2010.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2009] [Revised: 01/06/2010] [Accepted: 02/15/2010] [Indexed: 12/18/2022]
Abstract
A novel variant of histone H2A, named as testis specific expressed gene 1 (TSEG-1, approved symbol: H2afb1), was identified from adult mouse testis. The TSEG-1 gene is 610-bp in length and consists of one exon. TSEG-1 transcript was robustly and exclusively expressed in adult mouse testis, mainly in spermatocytes. In developmental testis, the TSEG-1 transcript was robustly expressed since postnatal day (P) 21, peaked at P30, and gradually decreased in the testis of aging mouse. The surgical cryptorchidism mouse model showed an increase in the TSEG-1 expression, accompanied by enhanced apoptosis of spermatogenic cells. The EGFP-tagged TSEG-1 protein is located in the nuclei of cultured spermatocytes (GC-2spd cells). Transfection of TSEG-1 into GC-2spd cells resulted in suppressed cell viabilities, increased apoptosis, and decreased mitochondrial membrane potential. Intratesticular injection of TSEG-1 resulted in increased apoptosis of spermatogenic cells in vivo. These results suggest that TSEG-1 may participate in the spermatogenesis via regulating the apoptosis of spermatogenic cells.
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Affiliation(s)
- Chaohui Gu
- Department of Surgery, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P R China
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Noguchi J, Ozawa M, Nakai M, Somfai T, Kikuchi K, Kaneko H, Kunieda T. Affected homologous chromosome pairing and phosphorylation of testis specific histone, H2AX, in male meiosis under FKBP6 deficiency. J Reprod Dev 2008; 54:203-7. [PMID: 18408354 DOI: 10.1262/jrd.19158] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A gene for FK506 binding protein 6 (Fkbp6) expresses during a specific stage of male and female meiosis. Disruption of the gene influences male reproduction, i.e. arrests spermatogenesis, but not female reproduction. Using the mouse model (targeted disruption), the role of the gene in homologous chromosome pairing has been demonstrated in a previous study. For further understanding the function of Fkbp6 in chromosome synapsis, we evaluated chromosome pairings during male meiosis in the as/as rat, a spontaneous null mutation, and compared them with those of the mouse model. Electron microscopy of the pachytene nuclei unveiled several types of abnormal chromosome pairing in the rat model, as shown in the mouse previously. The frequencies of aberrant pairings in the knockout mice and mutant rats were 42 of 67 nuclei (62.7%) and 20 out of 74 nuclei (27.0%), respectively. In order to clarify the mechanism of male specific infertility in Fkbp6 deficiency, the localization of gammaH2AX, a marker protein of XY chromosome inactivation during male meiosis, was examined. Immunostaining of gammaH2AX unveiled normal localization of the molecule to XY chromosomes (XY body) in both models, showing the independency of FKBP6 in sex chromosome inactivation. Besides the XY body, focal localization of gammaH2AX was observed in accordance with the unsynapsed chromosomes in both types of null animal. These results indicate the fundamental role of Fkbp6 in homologous chromosome synapsis during male meiosis. In conclusion, male specific infertility under Fkbp6 deficiency remains unsolved.
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Affiliation(s)
- Junko Noguchi
- Reproductive Biology Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Japan.
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Di Agostino S, Botti F, Di Carlo A, Sette C, Geremia R. Meiotic progression of isolated mouse spermatocytes under simulated microgravity. Reproduction 2004; 128:25-32. [PMID: 15232061 DOI: 10.1530/rep.1.00184] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Progression through the prophase of the first meiotic division can be obtained in culture by treatment of mouse spermatocytes with the serine/threonine phosphatase inhibitor okadaic acid. Chromosome condensation during this G2/M transition involves the activation of the MAPK pathway, which causes the activation of Nek2 and the phosphorylation of the chromatin architectural protein Hmga2. In an effort to set up conditions to allow a spontaneous progression of mouse spermatocytes through meiosis, we have investigated the cell-cycle features of these cells cultured for 24 h with a rotary cell culture system in a humidified atmosphere in a thermostatic incubator to simulate a microgravity environment. Morphological analysis of nuclear squashes indicated a 2-fold increase in late-pachytene spermatocytes with highly condensed chromosomes, and a contemporaneous decrease of mid-pachytene cells with less condensed chromatin. Microgravity induced a 2-fold activation of the cyclinB–cdc2 complex, confirming at the molecular level that cell-cycle progression had occurred. Moreover, using immuno-kinase assays with specific substrates we have demonstrated that the meiotic progression obtained under microgravity conditions is accompanied by activation of the Erk1/p90Rsk2 pathway. These data indicated that activation of the MAPK pathway correlates with chromatin condensation even under conditions in which meiotic progression occurs spontaneously and is not induced by a drug. We suggest that culture under microgravity conditions might help to release the block that inhibits isolated spermatocytes from progressing through prophase at unit gravity, and to study the physiological events of germ cell differentiationin vitro.
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Affiliation(s)
- Silvia Di Agostino
- Dipartimento di Sanità Pubblica e Biologia Cellulare, Università di Roma 'Tor Vergata', Via Montpellier 1, 00133, Rome, Italy
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Fernandez-Capetillo O, Mahadevaiah SK, Celeste A, Romanienko PJ, Camerini-Otero RD, Bonner WM, Manova K, Burgoyne P, Nussenzweig A. H2AX is required for chromatin remodeling and inactivation of sex chromosomes in male mouse meiosis. Dev Cell 2003; 4:497-508. [PMID: 12689589 DOI: 10.1016/s1534-5807(03)00093-5] [Citation(s) in RCA: 448] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
During meiotic prophase in male mammals, the X and Y chromosomes condense to form a macrochromatin body, termed the sex, or XY, body, within which X- and Y-linked genes are transcriptionally repressed. The molecular basis and biological function of both sex body formation and meiotic sex chromosome inactivation (MSCI) are unknown. A phosphorylated form of H2AX, a histone H2A variant implicated in DNA repair, accumulates in the sex body in a manner independent of meiotic recombination-associated double-strand breaks. Here we show that the X and Y chromosomes of histone H2AX-deficient spermatocytes fail to condense to form a sex body, do not initiate MSCI, and exhibit severe defects in meiotic pairing. Moreover, other sex body proteins, including macroH2A1.2 and XMR, do not preferentially localize with the sex chromosomes in the absence of H2AX. Thus, H2AX is required for the chromatin remodeling and associated silencing in male meiosis.
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Affiliation(s)
- Oscar Fernandez-Capetillo
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Vigodner M, Lewin LM, Shochat L, Mittelman L, Golan R. Meiosis in the golden hamster: a confocal microscopy and flow cytometric analysis. Mol Reprod Dev 2003; 64:86-95. [PMID: 12420303 DOI: 10.1002/mrd.10212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study, confocal microscopy and flow-cytometry were utilized to follow meiosis in hamster spermatogenesis. Confocal microscopy was used as an analytical tool to observe spermatocytes inside the tubules following meiotic progression consecutively at defined spermatogenic stages. To study spermatocyte differentiation, the structure of the synaptonemal complex was studied in detail at various stages of hamster spermatogenesis using the antibody against SC3 (the protein of axial/lateral element). The synaptonemal complex was observed from the leptotene stage until the first meiotic division with maximal staining in mid-pachytene spermatocytes, suggesting a role for SC3 at this postrecombinational stage. In addition, 3-dimensional (3D) images of synaptonemal complex were observed, providing information about spatial distribution of the chromosomes within the nuclei of spermatocytes at different stages of meiosis. Changes in spermatocyte sizes and DNA condensation allowed assessment of meiosis by flow cytometry. Changes in chromatin condensation at different stages of hamster meiosis were followed, revealing decondensation from early to late pachytene stages. The analysis also allowed a comparing of chromatin status of mitotic and meiotic chromosomes, confirming the less compact structure of the latter, possibly connected to increased transcriptional activity during meiosis.
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Affiliation(s)
- M Vigodner
- Department of Clinical Biochemistry, Sackler Medical School, Tel Aviv University, Ramat Aviv, Israel.
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